EP0616886A1 - Device for printing one sheet after the other and corresponding printing sheet - Google Patents

Device for printing one sheet after the other and corresponding printing sheet Download PDF

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Publication number
EP0616886A1
EP0616886A1 EP94490010A EP94490010A EP0616886A1 EP 0616886 A1 EP0616886 A1 EP 0616886A1 EP 94490010 A EP94490010 A EP 94490010A EP 94490010 A EP94490010 A EP 94490010A EP 0616886 A1 EP0616886 A1 EP 0616886A1
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EP
European Patent Office
Prior art keywords
plate
cylinder
electronic circuit
sheet
printing
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EP94490010A
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German (de)
French (fr)
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EP0616886B1 (en
Inventor
Jean Pierre Cuir
Gérard Cuir
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Cuir SA
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Cuir Gerard
Cuir Jean Pierre
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41F—PRINTING MACHINES OR PRESSES
    • B41F5/00—Rotary letterpress machines
    • B41F5/24—Rotary letterpress machines for flexographic printing
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41F—PRINTING MACHINES OR PRESSES
    • B41F13/00—Common details of rotary presses or machines
    • B41F13/004—Electric or hydraulic features of drives
    • B41F13/0045—Electric driving devices

Definitions

  • the present invention relates to an installation for sheet-fed printing of the flexographic type, of semi-rigid material such as corrugated cardboard, comprising a screened cylinder, a plate cylinder, a backpressure system and a transfer system. which feeds the sheets one by one between the plate cylinder and the back pressure cylinder. It relates more particularly to an installation of this type which is able to work with plates of different thicknesses.
  • the installations for sheet-by-sheet printing of the invention are intended to be used online, to carry out multi-sheet sheet printing.
  • the linear speed of the transfer system is equal to the linear speed of the plate which is mounted on the plate cylinder, in order to obtain non-slip contact between the sheet and the plate during printing. It is the same for the peripheral linear speed of the back pressure system when it is constituted by a back pressure cylinder.
  • the peripheral linear speed of the screened cylinder be equal to the linear speed of the plate.
  • the various aforementioned components are mechanically dependent and are driven by a single motor. Consequently, the above-mentioned speed equality conditions are only achieved for a given thickness of plate.
  • printers are sometimes required to mount on their installations of stereotypes of thickness different from that envisaged initially. In this case, the print quality deteriorates.
  • the printer must necessarily work with another installation operating with the chosen plate thickness.
  • rotary presses for flexographic printing of a strip of continuous material which in particular comprise a plate cylinder and a main cylinder on which the strip of material which is to be printed is wound, said main cylinder allowing the advancement of the material and also acting as a back-pressure cylinder.
  • a rotary press of this particular type which makes it possible to take into account the thickness of the plate used.
  • This rotary press is equipped with at least two motors which are mechanically independent, and allow the main cylinder to rotate in rotation for the first, and the plate cylinder for the second.
  • the plate cylinder motor is slaved in position relative to the main cylinder which serves as a reference, so that during the time interval when the plate is in contact with the strip of material, the speed of rotation of the cylinder plate holder is such that the linear speed of the plate is equal to the peripheral linear speed of the main cylinder.
  • the development of the plate holder determines the printing step. We can vary this step slightly. For this, it is necessary to vary the speed of rotation of the plate cylinder, during the time interval when the plate is not in contact with the material. This change in speed of rotation of the plate cylinder at each 360 ° rotation of this cylinder is only possible with plate cylinders of low inertia.
  • the greater the length of the plate which is mounted on the periphery of the plate cylinder the greater the speed variation which it will be necessary to communicate to the plate cylinder in order to maintain the distance between two patterns must be large.
  • Sheet-by-sheet printers unlike rotary presses such as that described in document FR 2 553 032 have non-interchangeable plate holders. Their dimensions are important and determine the maximum size of the sheet to be printed. Their inertias are therefore important and the pictures can cover almost the entire development of the picture cylinder.
  • the aim set by the applicant is to propose an improved installation for sheet-by-sheet printing, which overcomes the drawback observed in sheet-fed printers currently known, in that it allows automatic operation and in optimal conditions with plates of varying thickness, whatever the inertia of the plate cylinder or the length of the plate used.
  • the back pressure system can be constituted either by a fixed beam or by a back pressure cylinder. Being a back pressure cylinder, it is also possible that the same motor drives both the transfer system and the back pressure cylinder.
  • the printing rate corresponds to the time interval which separates the introduction of two successive sheets at the entry of the transfer system.
  • the speed of rotation of the plate cylinder depends solely on this printing rate which is entered as an operating parameter in the electronic circuit, and does not depend on the thickness or the length of the plate, unlike the plate cylinder from document FR 2 553 032. Consequently, the speed of rotation of the plate cylinder is not changed, and therefore the printing rate of the sheets, by changing the plate, and in particular by equipping the cylinder plate with a plate of different thickness. So when the printer wants to change the plate, and the plate he wants to mount on the plate holder has a thickness different from that of the previous plate, he just has to enter the electronic control circuit, at the help means input, the new data corresponding to this thickness.
  • the rotation of the plate cylinder is not affected by this change. Automatically the speed of rotation of the screened cylinder will undergo a suitable adjustment so that its peripheral linear speed is equal to the peripheral speed of the new photograph.
  • the speed of rotation of the third motor is automatically adjusted so that the speed of advancement of the sheets is equal to the linear speed of the plate, at least during the time interval when the plate is in contact with a sheet.
  • the first motor drives the plate cylinder with a predefined constant speed of rotation which fixes the printing rate
  • the plate cylinder is equipped with an encoder delivering for the electronic circuit, the reference signal, which is a function of the angular position of the plate cylinder.
  • the first motor is connected to the electronic control circuit which receives the reference signal as an input, and which is capable of controlling the rotation of the first motor in synchronism with said signal and as a function of the rate d 'impression.
  • the reference signal can be a purely electronic signal, which is generated from a clock and whose frequency can be modified.
  • this reference signal can also be the reference signal delivered by an installation of the invention produced according to the first particular embodiment, or be obtained from a other machine in line with installation.
  • the electronic circuit is capable, prior to the launching of sheet-by-sheet printing, of controlling the rotation of the first motor so as to bring the plate cylinder into an initial angular position which depends on a predefined timing parameter.
  • This setting parameter allows you to define the position of the printed pattern on the sheet.
  • the linear speed of the transfer system is strictly equal to the linear speed of the plate.
  • a sheet can slide slightly, and shift relative to the theoretical position it should have had, which induces a bad position of the printed pattern on the sheet.
  • the sheets may have lengths which differ slightly. If the introduction system ensures the synchronism of the front edge of the sheet with the installation and we want the print to be identified with respect to the rear edge, then we find registration errors. The same is true in the opposite case.
  • the embodiment of the installation of the invention also comprises, at the level of the transfer system, at least one location sensor which allows the detection of the passage of the edge d 'a sheet, and which is connected to the electronic circuit.
  • said electronic circuit is able, in synchronism with the reference signal, to control the rotation of the third motor, on the one hand during each time interval T1 where the photograph prints, so that the linear speed of the system transfer is equal to the linear speed of the plate and on the other hand during each time interval T2 where the plate does not print, so that the edge whose passage is detected at a determined distance from the pinch line reaches the level of said line when the plate cylinder is in a predetermined position.
  • the printing is calibrated, that is to say a precise positioning of the printing pattern on the sheet, relative to at the chosen edge.
  • the installation comprises two tracking sensors which are arranged at the level of the transfer system, one for the detection of the front edge, and the other for the detection of the rear edge of each sheet.
  • it also includes means for selecting one or the other sensor, which are connected to the electronic circuit.
  • the printer depending on whether he wishes to position the print pattern on the sheet relative to the front or rear edge of this sheet, chooses the sensor beforehand via the selection means.
  • the installation is also equipped with a device for adjusting the axial distance of the screened cylinder with respect to the plate cylinder, said device being provided with a fifth individual motor connected to the electronic circuit.
  • the electronic circuit is able to control the rotation of the fifth engine so as to bring the screened cylinder to a working position which depends on the thickness E c of the plate, and in which it is applied precisely on the surface of the shot.
  • the electronic circuit is advantageously capable of controlling the rotation of the fifth motor so as to control the movement of the screened cylinder from its position work to a retracting position, and vice versa, respectively whenever the edge of the next sheet is not or is detected again, and synchronously with the reference signal.
  • This allows the snapshot to be inked only when a sheet is available for printing. In practice, this change in position is synchronized so as to be carried out when the screen is facing the area of the plate holder without a plate.
  • the installation of the invention is also equipped with a device for adjusting the distance between the back-pressure system and the plate holder, said device being provided with a sixth individual motor connected to the electronic circuit.
  • the electronic circuit is able to control the rotation of the sixth individual motor so as to bring the back-pressure system into a working position which depends on the thickness E c of the plate and on the thickness of the sheets which must be printed.
  • a printing line for carrying out multiple sheet printing which typically comprises a plurality of installations of the invention, of which the plate cylinders are identical and are fitted with plates of the same thickness E c .
  • all of the motors in each installation are connected to a single electronic circuit.
  • All the plate cylinders of the line being identical, they will be rotated with the same rotation speed for a given printing rate. Clichés also having the same thickness, they will have identical linear speeds.
  • the printing line also includes an upstream machine of the feeder type, for the introduction of the sheets at the entry of the transfer system of the first installation of the printing line, it is necessary that the rate of he introduction of the sheets coincides with the printing rate, which is entered as a parameter in the electronic circuit. It is also necessary for the upstream machine to introduce the sheets by communicating to them a linear speed which is equal to the linear speed of the transfer system of said first installation. Consequently, the upstream machine will preferably also be controlled by the electronic circuit.
  • the printing line of the invention may include an installation produced according to the first particular embodiment mentioned above.
  • the reference signal corresponds to the signal delivered by the encoder of the plate cylinder of said installation.
  • the first motor of this installation then serves as a reference for the synchronization of all the motors of the other installations.
  • the flexographic printing line shown schematically in Figure 1 allows a double sheet printing sheet of a batch of sheets 1 1 a, in particular corrugated cardboard, and of equal length.
  • This particular line printer comprises a feeder 2 which allows the successive introduction at predetermined time intervals, each sheet 1a to the inlet of a first installation 3 of the invention.
  • Each sheet 1a printed by the installation 3 is then introduced into a second device 4 of the invention, which is located directly downstream of the first installation, and after being printed a second time is transferred to a cutter 5 .
  • the inking system 32 consists of a screened cylinder 33 and a rubber cylinder 34 which is tangent thereto.
  • the surface of the screened cylinder has a multitude of cells allowing it to receive the ink which is brought to the rubber cylinder using a pump, not shown.
  • the screened cylinder 33 allows in the course of its rotation an inking of the plate 31, which represents the pattern to be printed.
  • the transfer system 36 allows the transport of each sheet in the direction of the arrow D, from the inlet 37 of the transfer system 36, to the nip line 38 between the back pressure cylinder 35 and the door cylinder - shot 30.
  • the plate cylinder 30, the screen cylinder 33, the transfer system 36 and the back pressure cylinder 35 are each driven in rotation by a individual electronic servo motor, brushless motor type. According to the invention, all these motors are connected to an electronic circuit 7 for their position control.
  • the directions of rotation of the various elements making up the first installation 3 are represented by arrows in FIG. 1.
  • the first installation 3 also includes two sensors 39 a and 39 b of the photoelectric cell type which respectively allow the detection of the passage of the rear edge and the front edge of a sheet 1 a on the transfer system 36, and which are connected to the electronic circuit 7.
  • the second installation 4 is similar to the first installation 3 which has just been described, and is connected in the same way to the electronic circuit 7. Its description will therefore not be repeated. Note, however, that the pictures 31 and 41 can have different lengths. The same is true for transfer systems 36 and 46. However, it is necessary that the distance between the two pinch lines 38 and 48 of the two installations 3 and 4 as well as the distance between the pinch line 38 and the outlet of the feeder 2 are at least equal to the maximum length of the sheets to be printed.
  • the electronic circuit 7 receives as input a reference signal 6, of purely electronic type, for synchronization of the brushless motors of the two installations. It also includes a display screen 9 and input means, such as a keyboard 8, for entering the operating parameters of the two installations 3 and 4, including in particular the thickness E c of the photographs 31 and 41 and the line printing rate.
  • the operation of the printing line is as follows.
  • the printer enters, using the keyboard 8, the thickness E c of the plates 31 and 41 which have been mounted on the plate cylinders 30, 40, as well as the printing rate of the line, c ' that is to say the time interval T which separates the printing of two successive sheets.
  • the electronic circuit 7 automatically controls the rotation of the two plate cylinders 30, 40 in synchronism with the reference signal 6, so that they rotate 360 ° with a constant speed of rotation ⁇ c , during the time interval T.
  • This speed of rotation ⁇ c is therefore a function only of the printing rate which is chosen by l 'printer, and is not changed when changing cliché.
  • the feeder 2 is connected to the electronic circuit 7 which controls it so as to allow synchronous introduction with the reference signal 6, of a sheet 1 a at each time interval T, that is to say at each rotation of 360 ° of the plate cylinders 30.40.
  • the electronic circuit 7 is programmed to automatically slave the position of the brushless motors which rotate the counter-pressure cylinder 35 and the screened cylinder 33, respectively, so that the peripheral linear speed of these cylinders is equal to the linear speed of the plate 31.
  • This speed is a function only of the speed of rotation ⁇ c , of the radius R c of the plate cylinder 30, and of the thickness E c of plate 31.
  • This condition of equality between the speeds is important for the screened cylinder, especially when it is in contact with the plate 31, so as to ensure a uniform inking.
  • this condition of equality is necessary for the back-pressure cylinder 35, when the plate 31 is in contact with a sheet, so as to ensure non-slip contact during printing.
  • the rotation of the plate cylinder 30 can be broken down into two successive time intervals, T1 and T2, during which respectively the plate 31 prints, that is to say is located directly above the pinch line 38, and the plate does not print.
  • the electronic control circuit 7 is programmed to slave the brushless motor driving the transfer system 36 in position so that the linear speed of the transfer system is equal to the linear speed of the photograph 31 during the time interval T1.
  • the control circuit 7 is programmed to effect position and therefore speed corrections of the brushless motor driving the transfer system 36, as will now be described.
  • the printer selects, using the keypad 8, the locating sensor 39 b or 39 a.
  • the front or rear edge of each sheet introduced into the feeder 2 at the entry of the transfer system 36 passes in front of the sensor 39 b or 39 a for a predetermined position of the plate cylinder 30, which depends on the initial setting of this cylinder.
  • the sheets 1 may undergo a slight shift of the transfer system and shift in position with respect to the theoretical position that they should have.
  • the sheets 1 a may have slight differences in length, which the feeder 2 does not take into account in order to synchronize their introduction with respect to the reference signal 6.
  • the electronic circuit 7 compares the position of the plate cylinder 30 with respect to the theoretical position it should have, and controls the position of the motor driving the transfer system, according to the deviation, so as to precisely reposition the sheet 1a relative to the rotation of the plate 31. This correction is performed only during the time interval T2.
  • the control of the motors of the installation 4 by the electronic circuit 7 is similar to that of the motors of the installation 3, which has just been described, and does not will therefore not be repeated. Since the plate cylinders 30 and 40 have the same radius R c , and the same speed of rotation ⁇ c , and since the plates 31 and 41 have the same thickness E c , the linear speed of the plate 41 is equal to the linear speed of the screen 31. Consequently the screened cylinder 43 will have the same peripheral linear speed as the screened cylinder 33. Likewise, the transfer system 46 will have, during the time interval during which the screen 41 prints, the same linear speed as the transfer system 36 during the time period T1.
  • Each installation 3 and 4 also advantageously comprises a device for adjusting the position of the screened cylinder 33, 43, relative to the plate cylinder 30, 40, said device being equipped with an individual motor, of the brushless type controlled by the circuit.
  • electronics 7. Such a device is also well known and has already been described in particular in document FR 2 553 032.
  • the electronic circuit 7 is in this case programmed to bring the screened cylinder very precisely to its working position. 33 or 43 so that the surfaces of the plate cylinder 30 or 40 and the screen cylinder 33 or 43 are distant from the thickness E c .
  • a similar adjustment device can be used to position the back-pressure cylinder 35 or 45 relative to the plate cylinder 30 or 40, depending on the thickness E c of the plate, and the thickness of the sheets 1 a .
  • the electronic circuit 7 is also programmed to control the movement of the screened cylinder 33 or 43 from its working position to a retracting position, and vice versa, in synchronism with the reference signal, and according to the status of the tracking sensor that was selected.
  • This retraction principle applied to the screened cylinder 33 of the first installation 3 is illustrated in FIGS. 2A and 2B.
  • the plate 31 of the plate cylinder 30 is being printed on a sheet 1 a and the screened cylinder 33 is in the working position, and is applied tangentially to the plate 31.
  • the electronic circuit 7 controls the retraction of the cylinder screened 33 so as to bring it into the position illustrated in FIG. 2B. If one refers to Figure 2B, the sheet 1 a is absent, the anilox roller 33 is not in contact with the plate 31.
  • the electronic circuit 7 controls the lowering of the cylinder 33 to bring it into the working position, because a new sheet 1 a has been identified by the location sensor 39 a or 39 b which has been selected.
  • This positioning of the anilox roller 33 must be performed before the front edge 31a of the plate 31 arrives at the anilox cylinder 33.
  • the retraction of the engraved roller, in the absence of one or more sheets, avoids unnecessary inking of the plate which would cause an accumulation of ink, which can be detrimental to printing in that it results in more or less dark printed patterns.
  • the printing line of the invention has the advantage of being able to operate with any type of plate, and in particular with plates of varied thickness, without there being any need to make any modification to it.
  • changing the printing line shots does not change the rotational speed of the printing cylinders, and therefore does not require changing the printing rate.
  • the invention is not limited to the particular printing line which has just been described but covers all the variants thereof.
  • the back-pressure cylinders can be replaced by fixed beams, or be rotated by the motor of the corresponding transfer system.
  • the plate cylinder of one of the installations is equipped with an encoder delivering destination of the electronic circuit 7 a signal which is a function of the angular position of said cylinder, and which acts as a reference signal 6.
  • the motor of the plate cylinder can be a DC motor equipped with a variator speed, the speed of rotation of this motor being adjusted beforehand as a function of the printing rate of the line.

Abstract

The device (3,4) for the flexographic-type printing of sheets of a semi-rigid material, of the corrugated cardboard type, includes: - a plate-carrying cylinder (30, 40) to the periphery of which is fixed a plate (31, 41) of thickness Ec, - a counterpressure system, which is possibly a counterpressure cylinder (35, 45), - an engraved cylinder (33, 43), - and a transfer system (36, 46) to the entrance of which the sheets (1a) are fed one by one. Characteristically, it furthermore comprises: a) three or four motors which are mechanically independent and which drive round respectively the plate-carrying cylinder (30, 40) in the case of the first, the engraved cylinder (33, 43) in the case of the second, the transfer system (36, 46) in the case of the third, and possibly the counterpressure cylinder (35, 45) in the case of the fourth, b) and an electronic circuit (7) which is connected to the second, third and possibly fourth motors, which receives as input a reference signal (6) and which comprises means for entering the operating parameters, including at least the thickness Ec of the plate (31, 41) and the printing speed. The electronic circuit (7) is programmed to control the rotation of the said motors automatically as a function of the thickness Ec and of the printing speed, so as to obtain optimal printing. <IMAGE>

Description

La présente invention concerne une installation pour l'impression feuille à feuille de type flexographique, de matériau semi-rigide tel que du carton ondulé, comportant un cylindre tramé, un cylindre porte-cliché, un système de contre-pression et un système de transfert qui alimente les feuilles une à une entre le cylindre porte-cliché et le cylindre contre-pression. Elle concerne plus particulièrement une installation de ce type qui est apte à travailler avec des clichés de différentes épaisseurs. Les installations pour l'impression feuille à feuille de l'invention sont destinées à être utilisées en ligne, pour réaliser une impression feuille à feuille multiple.The present invention relates to an installation for sheet-fed printing of the flexographic type, of semi-rigid material such as corrugated cardboard, comprising a screened cylinder, a plate cylinder, a backpressure system and a transfer system. which feeds the sheets one by one between the plate cylinder and the back pressure cylinder. It relates more particularly to an installation of this type which is able to work with plates of different thicknesses. The installations for sheet-by-sheet printing of the invention are intended to be used online, to carry out multi-sheet sheet printing.

Pour obtenir une impression de qualité, il est important que dans de telles installations, la vitesse linéaire du système de transfert soit égale à la vitesse linéaire du cliché qui est monté sur le cylindre porte-cliché, afin d'obtenir un contact sans glissement entre la feuille et le cliché lors de l'impression. Il en est de même pour la vitesse linéaire périphérique du système de contre-pression lorsque celui-ci est constitué par un cylindre contre-pression. En outre, afin d'assurer un encrage homogène du cliché à chaque rotation du cylindre porte-cliché, il est également nécessaire que la vitesse linéaire périphérique du cylindre tramé soit égale à la vitesse linéaire du cliché. Dans les installations actuellement connues, les différents composants précités sont dépendants mécaniquement et sont entraînés par un moteur unique. Par conséquent, les conditions d'égalité de vitesse précitées ne sont réalisées que pour une épaisseur donnée de cliché. En pratique, de telles installations sont livrées par les constructeurs avec l'ensemble de leurs composants, qui sont conçus et agencés pour fonctionner avec un type précis de cliché, ayant une épaisseur donnée. Les cylindres porte-cliché sont usinés en tenant compte de l'épaisseur du cliché indiqué par l'imprimeur de manière à avoir un diamètre mesuré sur le cliché, constant pour un type de machine donné.To obtain a quality impression, it is important that in such installations, the linear speed of the transfer system is equal to the linear speed of the plate which is mounted on the plate cylinder, in order to obtain non-slip contact between the sheet and the plate during printing. It is the same for the peripheral linear speed of the back pressure system when it is constituted by a back pressure cylinder. In addition, in order to ensure a uniform inking of the plate at each rotation of the plate cylinder, it is also necessary that the peripheral linear speed of the screened cylinder be equal to the linear speed of the plate. In currently known installations, the various aforementioned components are mechanically dependent and are driven by a single motor. Consequently, the above-mentioned speed equality conditions are only achieved for a given thickness of plate. In practice, such installations are supplied by the manufacturers with all of their components, which are designed and arranged to operate with a specific type of plate, having a given thickness. The plate cylinders are machined taking into account the thickness of the plate indicated by the printer so as to have a diameter measured on the plate, constant for a given type of machine.

Cependant les imprimeurs sont parfois amenés à monter sur leurs installations des clichés d'épaisseur différente de celle prévue initialement. Dans ce cas, il s'ensuit une détérioration de la qualité d'impression. Lorsque l'épaisseur de cliché diffère de façon trop importante de celle pour laquelle l'installation est prévue, l'imprimeur doit obligatoirement travailler avec une autre installation fonctionnant avec l'épaisseur de cliché choisi.However, printers are sometimes required to mount on their installations of stereotypes of thickness different from that envisaged initially. In this case, the print quality deteriorates. When the plate thickness differs excessively from that for which the installation is planned, the printer must necessarily work with another installation operating with the chosen plate thickness.

Il existe également des presses rotatives pour l'impression flexographique, d'une bande de matériau continue, qui comportent notamment un cylindre porte-cliché et un cylindre principal sur lequel la bande de matériau qui doit être imprimée est enroulée, ledit cylindre principal permettant l'avancement du matériau et faisant également office de cylindre contre-pression. On connaît déjà, notamment par le document FR 2 553 032, une presse rotative de ce type particulier, qui permet de tenir compte de l'épaisseur de cliché utilisée. Cette presse rotative est équipée d'au moins deux moteurs qui sont indépendants mécaniquement, et permettent d'entraîner en rotation le cylindre principal pour le premier, et le cylindre porte-cliché pour le deuxième. Le moteur du cylindre porte-cliché est asservi en position par rapport au cylindre principal qui sert de référence, de manière à ce que pendant l'intervalle de temps où le cliché est en contact avec la bande de matériau, la vitesse de rotation du cylindre porte-cliché est telle que la vitesse linéaire du cliché est égale à la vitesse linéaire périphérique du cylindre principal. Sur ces machines, le développement du porte-cliché détermine le pas de l'impression. On peut faire varier légèrement ce pas. Pour cela, il est nécessaire de faire varier la vitesse de rotation du cylindre porte-cliché, pendant l'intervalle de temps où le cliché n'est pas en contact avec le matériau. Ce changement de vitesse de rotation du cylindre porte-cliché à chaque rotation de 360° de ce cylindre n'est possible qu'avec des cylindres porte-cliché de faible inertie. En outre, plus la longueur du cliché qui est monté à la périphérie du cylindre porte-cliché est importante, plus la variation de vitesse qu'il faudra communiquer au cylindre porte-cliché pour conserver la distance entre deux motifs devra être importante.There are also rotary presses for flexographic printing of a strip of continuous material, which in particular comprise a plate cylinder and a main cylinder on which the strip of material which is to be printed is wound, said main cylinder allowing the advancement of the material and also acting as a back-pressure cylinder. Already known, in particular from document FR 2 553 032, a rotary press of this particular type, which makes it possible to take into account the thickness of the plate used. This rotary press is equipped with at least two motors which are mechanically independent, and allow the main cylinder to rotate in rotation for the first, and the plate cylinder for the second. The plate cylinder motor is slaved in position relative to the main cylinder which serves as a reference, so that during the time interval when the plate is in contact with the strip of material, the speed of rotation of the cylinder plate holder is such that the linear speed of the plate is equal to the peripheral linear speed of the main cylinder. On these machines, the development of the plate holder determines the printing step. We can vary this step slightly. For this, it is necessary to vary the speed of rotation of the plate cylinder, during the time interval when the plate is not in contact with the material. This change in speed of rotation of the plate cylinder at each 360 ° rotation of this cylinder is only possible with plate cylinders of low inertia. In addition, the greater the length of the plate which is mounted on the periphery of the plate cylinder, the greater the speed variation which it will be necessary to communicate to the plate cylinder in order to maintain the distance between two patterns must be large.

Les imprimeuses feuille à feuille, contrairement aux presses rotatives telles que celle décrite dans le document FR 2 553 032 ont des porte-clichés non interchangeables. Leurs dimensions sont importantes et déterminent le format maximum de la feuille à imprimer. Leurs inerties sont donc importantes et les clichés peuvent couvrir la presque totalité du développement du cylindre porte-cliché.Sheet-by-sheet printers, unlike rotary presses such as that described in document FR 2 553 032 have non-interchangeable plate holders. Their dimensions are important and determine the maximum size of the sheet to be printed. Their inertias are therefore important and the pictures can cover almost the entire development of the picture cylinder.

Le but que s'est fixé le demandeur est de proposer une installation perfectionnée pour l'impression feuille à feuille, qui pallie l'inconvénient constaté dans les imprimeuses feuille à feuille actuellement connues, en ce qu'elle permet un fonctionnement automatique et dans des conditions optimales avec des clichés d'épaisseur variée, quelque soit l'inertie du cylindre porte-cliché ou la longueur du cliché utilisé.The aim set by the applicant is to propose an improved installation for sheet-by-sheet printing, which overcomes the drawback observed in sheet-fed printers currently known, in that it allows automatic operation and in optimal conditions with plates of varying thickness, whatever the inertia of the plate cylinder or the length of the plate used.

Ce but est parfaitement atteint par l'installation de l'invention qui, de manière connue, comporte :

  • un cylindre porte-cliché à la périphérie duquel est fixé un cliché d'épaisseur Ec,
  • un système de contre-pression, qui est éventuellement un cylindre contre-pression,
  • un cylindre tramé,
  • et un système de transfert à l'entrée duquel les feuilles sont introduites une à une et qui amène successivement chaque feuille jusqu'à la ligne de pincement entre le cylindre porte-cliché et le système de contre-pression.
This object is perfectly achieved by the installation of the invention which, in known manner, comprises:
  • a plate cylinder at the periphery of which is fixed a plate of thickness E c ,
  • a back pressure system, which is possibly a back pressure cylinder,
  • a screened cylinder,
  • and a transfer system at the entrance of which the sheets are introduced one by one and which successively brings each sheet to the nip between the plate cylinder and the back pressure system.

De manière caractéristique selon l'invention, l'installation comporte en outre :

  • a) trois ou quatre moteurs qui sont indépendants mécaniquement et qui entraînent en rotation respectivement le cylindre porte-cliché pour le premier, le cylindre tramé pour le deuxième, le système de transfert pour le troisième, et éventuellement le cylindre contre-pression pour le quatrième,
  • b) et un circuit électronique qui est connecté aux deuxième, troisième et éventuellement quatrième moteurs, qui reçoit en entrée un signal de référence et qui comprend des moyens d'entrée des paramètres de fonctionnement, dont au moins l'épaisseur Ec du cliché et la cadence d'impression.

Dans ce cas, le premier moteur entraîne en rotation le cylindre porte-cliché en synchronisme avec le signal de référence de telle sorte que le cylindre porte-cliché effectue un rotation de 360° à vitesse constante pendant l'intervalle de temps correspondant à la cadence d'impression le circuit électronique commande automatiquement la rotation des deuxième, troisième et éventuel quatrième moteurs, à partir du signal de référence et en fonction de l'épaisseur Ec, de telle sorte d'une part que la vitesse linéaire périphérique du cylindre tramé soit égale à la vitesse linéaire du cliché sur le porte-cliché, et d'autre part que la vitesse linéaire du système de transfert et éventuellement la vitesse linéaire périphérique du cylindre contre-pression soient égales à la vitesse linéaire du cliché sur le porte-cliché, pendant au moins l'intervalle de temps T₁ où le cliché imprime.Typically according to the invention, the installation further comprises:
  • a) three or four motors which are mechanically independent and which rotate the plate cylinder respectively for the first, the screen cylinder for the second, the transfer system for the third, and possibly the back pressure cylinder for the fourth ,
  • b) and an electronic circuit which is connected to the second, third and possibly fourth motors, which receives a reference signal as input and which comprises means for entering operating parameters, including at least the thickness E c of the plate and the printing rate.

In this case, the first motor rotates the plate cylinder in synchronism with the reference signal so that the plate cylinder rotates 360 ° at constant speed during the time interval corresponding to the rate the electronic circuit automatically controls the rotation of the second, third and possible fourth motors, from the reference signal and as a function of the thickness E c , so that on the one hand the peripheral linear speed of the screened cylinder is equal to the linear speed of the plate on the plate holder, and on the other hand that the linear speed of the transfer system and possibly the peripheral linear speed of the back-pressure cylinder are equal to the linear speed of the plate on the plate holder stereotype, during at least the time interval T₁ where the stereotype prints.

Le système de contre-pression peut être constitué soit par une poutre fixe, soit par un cylindre contre-pression. S'agissant d'un cylindre contre-pression, il est également possible que le même moteur entraîne à la fois le système de transfert et le cylindre contre-pression.The back pressure system can be constituted either by a fixed beam or by a back pressure cylinder. Being a back pressure cylinder, it is also possible that the same motor drives both the transfer system and the back pressure cylinder.

La cadence d'impression correspond à l'intervalle de temps qui sépare l'introduction de deux feuilles successives à l'entrée du système de transfert. La vitesse de rotation du cylindre porte-cliché dépend uniquement de cette cadence d'impression qui est entrée comme paramètre de fonctionnement dans le circuit électronique, et ne dépend pas de l'épaisseur ou de la longueur du cliché, contrairement au cylindre porte-cliché du document FR 2 553 032. Par conséquent, on ne modifie pas la vitesse de rotation du cylindre porte-cliché, et par là-même la cadence d'impression des feuilles, en changeant de cliché, et notamment en équipant le cylindre porte-cliché avec un cliché d'épaisseur différente. Ainsi lorsque l'imprimeur veut changer de cliché, et que le cliché qu'il souhaite monter sur le porte-cliché présente une épaisseur différente de celle du cliché précédent, il lui suffit d'entrer dans le circuit électronique de commande, à l'aide des moyens d'entrée, la nouvelle donnée correspondant à cette épaisseur. La rotation du cylindre porte-cliché n'est pas modifiée par ce changement. Automatiquement la vitesse de rotation du cylindre tramé va subir un réglage adapté pour que sa vitesse linéaire périphérique soit égale à la vitesse périphérique du nouveau cliché. La vitesse de rotation du troisième moteur est automatiquement réglée de manière à ce que la vitesse d'avancement des feuilles soit égale à la vitesse linéaire du cliché, au moins pendant l'intervalle de temps où le cliché est en contact avec une feuille.The printing rate corresponds to the time interval which separates the introduction of two successive sheets at the entry of the transfer system. The speed of rotation of the plate cylinder depends solely on this printing rate which is entered as an operating parameter in the electronic circuit, and does not depend on the thickness or the length of the plate, unlike the plate cylinder from document FR 2 553 032. Consequently, the speed of rotation of the plate cylinder is not changed, and therefore the printing rate of the sheets, by changing the plate, and in particular by equipping the cylinder plate with a plate of different thickness. So when the printer wants to change the plate, and the plate he wants to mount on the plate holder has a thickness different from that of the previous plate, he just has to enter the electronic control circuit, at the help means input, the new data corresponding to this thickness. The rotation of the plate cylinder is not affected by this change. Automatically the speed of rotation of the screened cylinder will undergo a suitable adjustment so that its peripheral linear speed is equal to the peripheral speed of the new photograph. The speed of rotation of the third motor is automatically adjusted so that the speed of advancement of the sheets is equal to the linear speed of the plate, at least during the time interval when the plate is in contact with a sheet.

Dans un premier mode particulier de réalisation, le premier moteur entraîne le cylindre porte-cliché avec une vitesse de rotation constante prédéfinie qui fixe la cadence d'impression, et le cylindre porte-cliché est équipé d'un codeur délivrant pour le circuit électronique, le signal de référence, qui est fonction de la position angulaire du cylindre porte-cliché.In a first particular embodiment, the first motor drives the plate cylinder with a predefined constant speed of rotation which fixes the printing rate, and the plate cylinder is equipped with an encoder delivering for the electronic circuit, the reference signal, which is a function of the angular position of the plate cylinder.

Dans un deuxième mode particulier de réalisation, le premier moteur est connecté au circuit électronique de commande qui reçoit en entrée le signal de référence, et qui est apte à contrôler la rotation du premier moteur en synchronisme avec ledit signal et en fonction de la cadence d'impression. Dans ce cas, le signal de référence peut être un signal purement électronique, qui est généré à partir d'une horloge et dont la fréquence est modifiable. Quand l'installation fait partie d'une ligne d'impression, ce signal de référence peut également être le signal de référence délivré par une installation de l'invention réalisée selon le premier mode particulier de réalisation, ou être obtenu à partir d'une autre machine en ligne avec l'installation.In a second particular embodiment, the first motor is connected to the electronic control circuit which receives the reference signal as an input, and which is capable of controlling the rotation of the first motor in synchronism with said signal and as a function of the rate d 'impression. In this case, the reference signal can be a purely electronic signal, which is generated from a clock and whose frequency can be modified. When the installation is part of a printing line, this reference signal can also be the reference signal delivered by an installation of the invention produced according to the first particular embodiment, or be obtained from a other machine in line with installation.

De préférence, dans le deuxième mode particulier de réalisation, le circuit électronique est apte, préalablement au lancement de l'impression feuille à feuille, à contrôler la rotation du premier moteur de manière à amener le cylindre porte-cliché dans une position angulaire initiale qui dépend d'un paramètre de calage prédéfini. Ce paramètre de calage permet de définir la position du motif imprimé sur la feuille.Preferably, in the second particular embodiment, the electronic circuit is capable, prior to the launching of sheet-by-sheet printing, of controlling the rotation of the first motor so as to bring the plate cylinder into an initial angular position which depends on a predefined timing parameter. This setting parameter allows you to define the position of the printed pattern on the sheet.

En théorie, pour que le motif soit toujours imprimé au bon endroit sur la feuille, il suffit que la vitesse linéaire du système de transfert soit rigoureusement égale à la vitesse linéaire du cliché. En pratique, au cours de son passage sur le système de transfert, une feuille peut glisser légèrement , et se décaler par rapport à la position théorique qu'elle aurait dû avoir, ce qui induit une mauvaise position du motif imprimé sur la feuille. D'autre part, les feuilles peuvent avoir des longueurs qui diffèrent légèrement. Si le système d'introduction assure le synchronisme du bord avant de la feuille avec l'installation et que l'on veut que l'impression soit repérée par rapport au bord arrière, on constate alors des défauts de repérage. Il en est de même dans le cas inverse. Afin de pallier tous ces inconvénients, quelque soit le mode de réalisation de l'installation de l'invention, celle-ci comporte en outre au niveau du système de transfert , au moins un capteur de repérage qui permet la détection du passage du bord d'une feuille, et qui est connecté au circuit électronique. Dans ce cas ledit circuit électronique est apte , en synchronisme avec le signal de référence, à contrôler la rotation du troisième moteur, d'une part pendant chaque intervalle de temps T₁ où le cliché imprime, de telle sorte que la vitesse linéaire du système de transfert soit égale à la vitesse linéaire du cliché et d'autre part pendant chaque intervalle de temps T₂ où le cliché n'imprime pas, de telle sorte que le bord dont on détecte le passage à une distance déterminée de la ligne de pincement arrive au niveau de ladite ligne lorsque le cylindre porte-cliché est dans une position prédéterminée. Selon que l'on détecte le passage du bord avant ou du bord arrière d'une feuille, on effectue un calage de l'impression, c'est-à-dire un positionnement précis du motif d'impression sur la feuille, par rapport au bord choisi.In theory, so that the pattern is always printed in the right place on the sheet, it is sufficient that the linear speed of the transfer system is strictly equal to the linear speed of the plate. In practice, during its passage over the transfer system, a sheet can slide slightly, and shift relative to the theoretical position it should have had, which induces a bad position of the printed pattern on the sheet. On the other hand, the sheets may have lengths which differ slightly. If the introduction system ensures the synchronism of the front edge of the sheet with the installation and we want the print to be identified with respect to the rear edge, then we find registration errors. The same is true in the opposite case. In order to overcome all these drawbacks, whatever the embodiment of the installation of the invention, it also comprises, at the level of the transfer system, at least one location sensor which allows the detection of the passage of the edge d 'a sheet, and which is connected to the electronic circuit. In this case, said electronic circuit is able, in synchronism with the reference signal, to control the rotation of the third motor, on the one hand during each time interval T₁ where the photograph prints, so that the linear speed of the system transfer is equal to the linear speed of the plate and on the other hand during each time interval T₂ where the plate does not print, so that the edge whose passage is detected at a determined distance from the pinch line reaches the level of said line when the plate cylinder is in a predetermined position. Depending on whether the passage of the front edge or the rear edge of a sheet is detected, the printing is calibrated, that is to say a precise positioning of the printing pattern on the sheet, relative to at the chosen edge.

Avantageusement l'installation comporte deux capteurs de repérage qui sont disposés au niveau du système de transfert, l'un pour la détection du bord avant, et l'autre pour la détection du bord arrière de chaque feuille. Dans ce cas elle comprend également des moyens de sélection de l'un ou l'autre capteur, qui sont reliés au circuit électronique. L'imprimeur, selon qu'il souhaite positionner le motif d'impression sur la feuille par rapport au bord avant ou arrière de cette feuille, choisit préalablement le capteur par l'intermédiaire des moyens de sélection.Advantageously, the installation comprises two tracking sensors which are arranged at the level of the transfer system, one for the detection of the front edge, and the other for the detection of the rear edge of each sheet. In this case, it also includes means for selecting one or the other sensor, which are connected to the electronic circuit. The printer, depending on whether he wishes to position the print pattern on the sheet relative to the front or rear edge of this sheet, chooses the sensor beforehand via the selection means.

De préférence, l'installation est également équipée d'un dispositif de réglage de la distance axiale du cylindre tramé par rapport au cylindre porte-cliché, ledit dispositif étant muni d'un cinquième moteur individuel connecté au circuit électronique. Dans ce cas le circuit électronique est apte à contrôler la rotation du cinquième moteur de manière à amener le cylindre tramé jusqu'à une position de travail qui dépend de l'épaisseur Ec du cliché, et dans laquelle il vient s'appliquer précisément sur la surface du cliché.Preferably, the installation is also equipped with a device for adjusting the axial distance of the screened cylinder with respect to the plate cylinder, said device being provided with a fifth individual motor connected to the electronic circuit. In this case, the electronic circuit is able to control the rotation of the fifth engine so as to bring the screened cylinder to a working position which depends on the thickness E c of the plate, and in which it is applied precisely on the surface of the shot.

Dans le cas où l'installation comporte à la fois au moins un capteur de repérage et le dispositif de réglage précité, le circuit électronique est avantageusement apte à contrôler la rotation du cinquième moteur de manière à commander le déplacement du cylindre tramé de sa position de travail jusqu'à une position d'escamotage, et vice et versa, respectivement chaque fois que le bord de la feuille suivante n'est pas ou est de nouveau détecté, et de façon synchrone avec le signal de référence. Cela permet d'encrer le cliché uniquement lorsqu'une feuille se présente pour l'impression. En pratique, ce changement de position est synchronisé de manière à être effectué lorsque le tramé est au regard de la zone du porte-cliché dépourvu de cliché.In the case where the installation includes both at least one location sensor and the aforementioned adjustment device, the electronic circuit is advantageously capable of controlling the rotation of the fifth motor so as to control the movement of the screened cylinder from its position work to a retracting position, and vice versa, respectively whenever the edge of the next sheet is not or is detected again, and synchronously with the reference signal. This allows the snapshot to be inked only when a sheet is available for printing. In practice, this change in position is synchronized so as to be carried out when the screen is facing the area of the plate holder without a plate.

Avantageusement l'installation de l'invention est également équipée d'un dispositif de réglage de la distance entre le système de contre-pression et le porte-cliché, ledit dispositif étant muni d'un sixième moteur individuel connecté au circuit électronique. Dans ce cas, le circuit électronique est apte à contrôler la rotation du sixième moteur individuel de manière à amener le système de contre-pression dans une position de travail qui dépend de l'épaisseur Ec du cliché et de l'épaisseur des feuilles qui doivent être imprimées.Advantageously, the installation of the invention is also equipped with a device for adjusting the distance between the back-pressure system and the plate holder, said device being provided with a sixth individual motor connected to the electronic circuit. In this case, the electronic circuit is able to control the rotation of the sixth individual motor so as to bring the back-pressure system into a working position which depends on the thickness E c of the plate and on the thickness of the sheets which must be printed.

L'invention a pour autre objet une ligne d'impression pour réaliser une impression feuille à feuille multiple qui de manière caractéristique comporte une pluralité d'installations de l'invention, dont les cylindres porte-cliché sont identiques et sont équipés de clichés de même épaisseur Ec. Dans ce cas, l'ensemble des moteurs de chaque installation est connecté à un unique circuit électronique. Tous les cylindres porte-cliché de la ligne étant identiques, ils seront entrainés en rotation avec la même vitesse de rotation pour une cadence d'impression donnée. Les clichés ayant en outre la même épaisseur, ils auront des vitesses lineaires identiques. Dans le cas où la ligne d'impression comporte également une machine amont du type margeur, pour l'introduction des feuilles à l'entrée du système de transfert de la première installation de la ligne d'impression, il est nécéssaire que la cadence d'introduction des feuilles coincident avec la cadence d'impression, qui est entrée comme paramètre dans le cicuit électronique. Il est également nécessaire que la machine amont introduise les feuilles en leur communiquant une vitesse linéaire qui est égale à la vitesse linéaire du système de transfert de ladite première installation. Par conséquent, la machine amont sera de préférence également pilotée par le circuit électronique.Another subject of the invention is a printing line for carrying out multiple sheet printing which typically comprises a plurality of installations of the invention, of which the plate cylinders are identical and are fitted with plates of the same thickness E c . In this case, all of the motors in each installation are connected to a single electronic circuit. All the plate cylinders of the line being identical, they will be rotated with the same rotation speed for a given printing rate. Clichés also having the same thickness, they will have identical linear speeds. In the case where the printing line also includes an upstream machine of the feeder type, for the introduction of the sheets at the entry of the transfer system of the first installation of the printing line, it is necessary that the rate of he introduction of the sheets coincides with the printing rate, which is entered as a parameter in the electronic circuit. It is also necessary for the upstream machine to introduce the sheets by communicating to them a linear speed which is equal to the linear speed of the transfer system of said first installation. Consequently, the upstream machine will preferably also be controlled by the electronic circuit.

Plus particulièrement, la ligne d'impression de l'invention peut comporter une installation réalisée selon le premier mode particulier de réalisation précité. Dans ce cas, le signal de référence correspond au signal délivré par le codeur du cylindre porte-cliché de ladite installation. Le premier moteur de cette installation sert alors de référence pour la synchronisation de tous les moteurs des autres installations.More particularly, the printing line of the invention may include an installation produced according to the first particular embodiment mentioned above. In this case, the reference signal corresponds to the signal delivered by the encoder of the plate cylinder of said installation. The first motor of this installation then serves as a reference for the synchronization of all the motors of the other installations.

D'autres caractéristiques et avantages de l' invention ressortiront de la description suivante d'un mode particulier de réalisation d'une ligne d'impression flexographique selon l'invention, donnée en référence aux dessins annexés sur lesquels :

  • la figure 1 est une représentation schématique d'une ligne d'impression de l'invention, comportant deux installations pour l'impression flexographique feuille à feuille,
  • et les figure 2A et 2B illustrent le principe d'escamotage du cylindre tramé d'une installation de l'invention.
Other characteristics and advantages of the invention will emerge from the following description of a particular embodiment of a flexographic printing line according to the invention, given with reference to the appended drawings in which:
  • FIG. 1 is a schematic representation of a printing line of the invention, comprising two installations for flexographic printing sheet by sheet,
  • and FIGS. 2A and 2B illustrate the principle of retraction of the screened cylinder of a installation of the invention.

La ligne d'impression flexographique représentée schématiquement à la figure 1, à titre d'exemple non limitatif, permet de réaliser une double impression feuille à feuille d'un lot 1 de feuilles 1a, notamment en carton ondulé, et de longueur identique. Cette ligne particulière d'impression comporte un margeur 2 qui permet l'introduction successive, à intervalles de temps prédéterminés, de chaque feuille 1a à l'entrée d'une première installation 3 de l'invention. Chaque feuille 1a imprimée par l'installation 3 est ensuite introduite dans une deuxième installation 4 de l'invention, qui est située directement en aval de la première installation, puis après avoir été une seconde fois imprimée est transférée jusqu'à une découpeuse 5.The flexographic printing line shown schematically in Figure 1, by way of non-limiting example, allows a double sheet printing sheet of a batch of sheets 1 1 a, in particular corrugated cardboard, and of equal length. This particular line printer comprises a feeder 2 which allows the successive introduction at predetermined time intervals, each sheet 1a to the inlet of a first installation 3 of the invention. Each sheet 1a printed by the installation 3 is then introduced into a second device 4 of the invention, which is located directly downstream of the first installation, and after being printed a second time is transferred to a cutter 5 .

La première installation 3 comporte :

  • un cylindre porte-cliché 30 de rayon Rc, à la périphérie duquel est monté un cliché 31, d'épaisseur Ec,
  • un système d'encrage 32,
  • un cylindre contre-pression 35,
  • un système de transfert 36, du type courroie crantée.
The first installation 3 comprises:
  • a plate cylinder 30 of radius R c , at the periphery of which a plate 31, of thickness E c , is mounted,
  • an inking system 32,
  • a back pressure cylinder 35,
  • a transfer system 36, of the toothed belt type.

Le système d'encrage 32 consiste en un cylindre tramé 33 et un cylindre caoutchouc 34 qui lui est tangent. La surface du cylindre tramé comporte une multitude d'alvéoles lui permettant de recevoir l'encre qui est amenée sur le cylindre de caoutchouc à l'aide d'une pompe non représentée. Le cylindre tramé 33 permet au cours de sa rotation un encrage du cliché 31, qui représente le motif à imprimer.The inking system 32 consists of a screened cylinder 33 and a rubber cylinder 34 which is tangent thereto. The surface of the screened cylinder has a multitude of cells allowing it to receive the ink which is brought to the rubber cylinder using a pump, not shown. The screened cylinder 33 allows in the course of its rotation an inking of the plate 31, which represents the pattern to be printed.

Le système de transfert 36 permet le transport de chaque feuille dans le sens de la flèche D, depuis l'entrée 37 du système de transfert 36, jusqu'à la ligne de pincement 38 entre le cylindre de contre-pression 35 et le cylindre porte-cliché 30.The transfer system 36 allows the transport of each sheet in the direction of the arrow D, from the inlet 37 of the transfer system 36, to the nip line 38 between the back pressure cylinder 35 and the door cylinder - shot 30.

Le cylindre porte-cliché 30, le cylindre tramé 33, le système de transfert 36 et le cylindre contre-pression 35 sont entraînés chacun en rotation par un moteur individuel à asservissement électronique, du type moteur brushless. Conformément à l'invention, tous ces moteurs sont reliés à un circuit électronique 7 pour leur asservissement en position. Les sens de rotation des différents éléments composant la première installation 3 sont représentés par des flèches sur la figure 1.The plate cylinder 30, the screen cylinder 33, the transfer system 36 and the back pressure cylinder 35 are each driven in rotation by a individual electronic servo motor, brushless motor type. According to the invention, all these motors are connected to an electronic circuit 7 for their position control. The directions of rotation of the various elements making up the first installation 3 are represented by arrows in FIG. 1.

La première installation 3 comporte également deux capteurs 39a et 39b du type cellule photo-électrique qui permettent respectivement la détection du passage du bord arrière et du bord avant d'une feuille 1a sur le système de transfert 36, et qui sont connectés au circuit électronique 7.The first installation 3 also includes two sensors 39 a and 39 b of the photoelectric cell type which respectively allow the detection of the passage of the rear edge and the front edge of a sheet 1 a on the transfer system 36, and which are connected to the electronic circuit 7.

La deuxième installation 4 est similaire à la première installation 3 qui vient d'être décrite, et est connecté de la même façon au circuit électronique 7. Sa description ne sera donc pas répétée. On notera cependant que les clichés 31 et 41 peuvent avoir des longueurs différentes. Il en est de même pour les systèmes de transfert 36 et 46. Il est cependant nécessaire que la distance entre les deux lignes de pincement 38 et 48 des deux installations 3 et 4 ainsi que la distance entre la ligne de pincement 38 et la sortie du margeur 2 soient au moins égales à la longueur maximale des feuilles que l'on imprime.The second installation 4 is similar to the first installation 3 which has just been described, and is connected in the same way to the electronic circuit 7. Its description will therefore not be repeated. Note, however, that the pictures 31 and 41 can have different lengths. The same is true for transfer systems 36 and 46. However, it is necessary that the distance between the two pinch lines 38 and 48 of the two installations 3 and 4 as well as the distance between the pinch line 38 and the outlet of the feeder 2 are at least equal to the maximum length of the sheets to be printed.

Le circuit électronique 7 reçoit en entrée un signal de référence 6, de type purement électronique, pour la synchronisation des moteurs brushless des deux installations. Il comprend également un écran de visualisation 9 et des moyens d'entrée, tels qu'un clavier 8, pour la saisie des paramètres de fonctionnement des deux installations 3 et 4, dont notamment l'épaisseur Ec des clichés 31 et 41 et la cadence d'impression de la ligne.The electronic circuit 7 receives as input a reference signal 6, of purely electronic type, for synchronization of the brushless motors of the two installations. It also includes a display screen 9 and input means, such as a keyboard 8, for entering the operating parameters of the two installations 3 and 4, including in particular the thickness E c of the photographs 31 and 41 and the line printing rate.

Le fonctionnement de la ligne d'impression est le suivant. l'imprimeur saisit ,à l'aide du clavier 8, l'épaisseur Ec des clichés 31 et 41 qui ont été montés sur les cylindres porte-cliché 30 ,40, ainsi que la cadence d'impression de la ligne, c'est à dire l'intervalle de temps T qui sépare l'impression de deux feuilles successives. Le circuit électronique 7 commande automatiquement la rotation des deux cylindres porte-cliché 30,40 en synchronisme avec le signal de référence 6, de telle sorte qu'ils effectuent une rotation de 360° avec une vitesse de rotation constante Ωc, pendant l'intervalle de temps T. Cette vitesse de rotation Ωc est donc fonction uniquement de la cadence d'impression qui est choisie par l'imprimeur, et n'est pas modifiée lorsque l'on change de cliché.The operation of the printing line is as follows. the printer enters, using the keyboard 8, the thickness E c of the plates 31 and 41 which have been mounted on the plate cylinders 30, 40, as well as the printing rate of the line, c ' that is to say the time interval T which separates the printing of two successive sheets. The electronic circuit 7 automatically controls the rotation of the two plate cylinders 30, 40 in synchronism with the reference signal 6, so that they rotate 360 ° with a constant speed of rotation Ω c , during the time interval T. This speed of rotation Ω c is therefore a function only of the printing rate which is chosen by l 'printer, and is not changed when changing cliché.

Le margeur 2 est connecté au circuit électronique 7 qui le commande de manière à permettre une introduction synchrone avec le signal de référence 6, d'une feuille 1a à chaque intervalle de temps T, c'est-à-dire à chaque rotation de 360 ° des cylindres porte-cliché 30,40.The feeder 2 is connected to the electronic circuit 7 which controls it so as to allow synchronous introduction with the reference signal 6, of a sheet 1 a at each time interval T, that is to say at each rotation of 360 ° of the plate cylinders 30.40.

S'agissant d'une impression feuille à feuille, il est très important que le motif imprimé sur chaque feuille soit toujours situé à la même distance soit du bord avant, soit du bord arrière de ladite feuille. Cette distance est encore appelée distance de calage. Pour régler la distance de calage de chaque installation 3, 4, il est nécessaire, préalablement au commencement de l'impression d'effectuer un positionnement précis de chaque cylindre porte-cliché 30, 40. Ce positionnement est commandé par le circuit électronique 7 en fonction d'un paramètre de calage qui est entré par l'imprimeur à l'aide du clavier 8, et qui peut être affiché sur un écran 9.As it is a sheet-by-sheet printing, it is very important that the pattern printed on each sheet is always located at the same distance either from the front edge or from the rear edge of said sheet. This distance is also called stall distance. To adjust the setting distance of each installation 3, 4, it is necessary, prior to the start of printing, to perform a precise positioning of each plate cylinder 30, 40. This positioning is controlled by the electronic circuit 7 in function of a setting parameter which is entered by the printer using the keyboard 8, and which can be displayed on a screen 9.

Le circuit électronique 7 est programmé pour asservir automatiquement la position des moteurs brushless qui entraînent en rotation respectivement le cylindre contre-pression 35 et le cylindre tramé 33, de manière à ce que la vitesse linéaire périphérique de ces cylindres soit égale à la vitesse linéaire du cliché 31. Cette vitesse est fonction uniquement de la vitesse de rotation Ωc, du rayon Rc du cylindre porte-cliché 30, et de l'épaisseur Ec du cliché 31. Cette condition d'égalité entre les vitesses, est importante pour le cylindre tramé, surtout lorsqu'il est en contact avec le cliché 31, de manière à en assurer un encrage homogène. De même, cette condition d'égalité est nécessaire pour le cylindre contre-pression 35, lorsque le cliché 31 est en contact avec une feuille, de manière à assurer un contact sans glissement au cours de l'impression.The electronic circuit 7 is programmed to automatically slave the position of the brushless motors which rotate the counter-pressure cylinder 35 and the screened cylinder 33, respectively, so that the peripheral linear speed of these cylinders is equal to the linear speed of the plate 31. This speed is a function only of the speed of rotation Ω c , of the radius R c of the plate cylinder 30, and of the thickness E c of plate 31. This condition of equality between the speeds is important for the screened cylinder, especially when it is in contact with the plate 31, so as to ensure a uniform inking. Likewise, this condition of equality is necessary for the back-pressure cylinder 35, when the plate 31 is in contact with a sheet, so as to ensure non-slip contact during printing.

La rotation du cylindre porte-cliché 30 peut se décomposer en deux intervalles de temps successifs, T₁ et T₂, pendant lesquels respectivement le cliché 31 imprime, c'est-à-dire est situé à l'aplomb de la ligne de pincement 38, et le cliché n'imprime pas. Le circuit électronique de commande 7 est programmé pour asservir en position le moteur brushless entraînant le système de transfert 36 de manière à ce que la vitesse linéaire du système de transfert soit égale à la vitesse linéaire du cliché 31 pendant l'intervalle de temps T₁. Pendant l'intervalle de temps T₂, le circuit de commande 7 est programmé pour effectuer des corrections de position et par là même de vitesse du moteur brushless entraînant le système de transfert 36, tel que cela va être à présent décrit.The rotation of the plate cylinder 30 can be broken down into two successive time intervals, T₁ and T₂, during which respectively the plate 31 prints, that is to say is located directly above the pinch line 38, and the plate does not print. The electronic control circuit 7 is programmed to slave the brushless motor driving the transfer system 36 in position so that the linear speed of the transfer system is equal to the linear speed of the photograph 31 during the time interval T₁. During the time interval T₂, the control circuit 7 is programmed to effect position and therefore speed corrections of the brushless motor driving the transfer system 36, as will now be described.

Selon que l'impression doit être repérée par rapport au bord avant ou au bord arrière d'une feuille 1a, l'imprimeur sélectionne, à l'aide du clavier 8, le capteur de repérage 39b ou 39a. En théorie, le bord avant ou arrière de chaque feuille introduite dans le margeur 2 à l'entrée du système de transfert 36 passe devant le capteur 39b ou 39a pour une position prédéterminée du cylindre porte-cliché 30, qui dépend du calage initial de ce cylindre. En pratique, il peut arriver que les feuilles 1a subissent un léger glissement sur le système de transfert et se décalent en position par rapport à la position théorique qu'elles devraient avoir. En outre, les feuilles 1a peuvent présenter de légères différences de longueur, dont le margeur 2 ne tient pas compte pour synchroniser leur introduction par rapport au signal de référence 6. Pour pallier ces inconvénients, à chaque fois que le capteur de repérage 39b ou 39a qui a été sélectionné détecte le passage du bord avant ou arrière d'une feuille, le circuit électronique 7 compare la position du cylindre porte-cliché 30 par rapport à la position théorique qu'il devrait avoir, et asservit la position du moteur entraînant le système de transfert, en fonction de l'écart constaté, de manière à repositionner précisément la feuille 1a par rapport à la rotation du cliché 31. Cette correction est effectuée uniquement pendant l'intervalle de temps T₂.Depending on whether printing is to be identified with respect to the front edge or rear edge of a sheet 1a, the printer selects, using the keypad 8, the locating sensor 39 b or 39 a. In theory, the front or rear edge of each sheet introduced into the feeder 2 at the entry of the transfer system 36 passes in front of the sensor 39 b or 39 a for a predetermined position of the plate cylinder 30, which depends on the initial setting of this cylinder. In practice, it may happen that the sheets 1 to undergo a slight shift of the transfer system and shift in position with respect to the theoretical position that they should have. In addition, the sheets 1 a may have slight differences in length, which the feeder 2 does not take into account in order to synchronize their introduction with respect to the reference signal 6. To overcome these drawbacks, each time that the tracking sensor 39 b or 39 a which has been selected detects the passage of the front or rear edge of a sheet, the electronic circuit 7 compares the position of the plate cylinder 30 with respect to the theoretical position it should have, and controls the position of the motor driving the transfer system, according to the deviation, so as to precisely reposition the sheet 1a relative to the rotation of the plate 31. This correction is performed only during the time interval T₂.

L'asservissement des moteurs de l'installation 4 par le circuit électronique 7 est similaire à celui des moteurs de l'installation 3, qui vient d'être décrit, et ne sera donc pas répété. Etant donné que les cylindres porte-cliché 30 et 40 ont le même rayon Rc, et la même vitesse de rotation Ωc, et que les clichés 31 et 41 ont la même épaisseur Ec, la vitesse linéaire du cliché 41 est égale à la vitesse linéaire du cliché 31. Par conséquent le cylindre tramé 43 aura la même vitesse linéaire périphérique que le cylindre tramé 33. De même , le système de transfert 46 aura pendant l'intervalle de temps au cours duquel le cliché 41 imprime, la même vitesse linéaire que le système de transfert 36 pendant la période de temps T₁.The control of the motors of the installation 4 by the electronic circuit 7 is similar to that of the motors of the installation 3, which has just been described, and does not will therefore not be repeated. Since the plate cylinders 30 and 40 have the same radius R c , and the same speed of rotation Ω c , and since the plates 31 and 41 have the same thickness E c , the linear speed of the plate 41 is equal to the linear speed of the screen 31. Consequently the screened cylinder 43 will have the same peripheral linear speed as the screened cylinder 33. Likewise, the transfer system 46 will have, during the time interval during which the screen 41 prints, the same linear speed as the transfer system 36 during the time period T₁.

Pour que chaque feuille introduite par le margeur 2 se positionne correctement sur le système de transfert 36, il est nécessaire que la vitesse qui lui est communiquée par le margeur au moment de son introduction soit sensiblement égale à la vitesse linéaire du système de transfert.So that each sheet introduced by the feeder 2 is positioned correctly on the transfer system 36, it is necessary that the speed communicated to it by the feeder at the time of its introduction is substantially equal to the linear speed of the transfer system.

Chaque installation 3 et 4 comprend également avantageusement un dispositif de réglage de la position du cylindre tramé 33, 43, par rapport au cylindre porte-cliché 30, 40, ledit dispositif étant équipé d'un moteur individuel, de type brushless piloté par le circuit électronique 7. Un tel dispositif est par ailleurs bien connu et a déjà été décrit notamment dans le document FR 2 553 032. Le circuit électronique 7 est dans ce cas programmé pour amener de façon très précise jusqu'à sa position de travail le cylindre tramé 33 ou 43 de manière à ce que les surfaces du cylindre porte-cliché 30 ou 40 et du cylindre tramé 33 ou 43 soient distantes de l'épaisseur Ec. Un dispositif de réglage similaire peut être utilisé pour réaliser un positionnement du cylindre contre-pression 35 ou 45 par rapport au cylindre porte-cliché 30 ou 40, en fonction de l'épaisseur Ec du cliché, et de l'épaisseur des feuilles 1a.Each installation 3 and 4 also advantageously comprises a device for adjusting the position of the screened cylinder 33, 43, relative to the plate cylinder 30, 40, said device being equipped with an individual motor, of the brushless type controlled by the circuit. electronics 7. Such a device is also well known and has already been described in particular in document FR 2 553 032. The electronic circuit 7 is in this case programmed to bring the screened cylinder very precisely to its working position. 33 or 43 so that the surfaces of the plate cylinder 30 or 40 and the screen cylinder 33 or 43 are distant from the thickness E c . A similar adjustment device can be used to position the back-pressure cylinder 35 or 45 relative to the plate cylinder 30 or 40, depending on the thickness E c of the plate, and the thickness of the sheets 1 a .

De préférence le circuit électronique 7 est également programmé pour commander le déplacement du cylindre tramé 33 ou 43 de sa position de travail jusqu'à une position d'escamotage, et vice versa, en synchronisme avec le signal de référence, et en fonction de l'état du capteur de repérage qui était sélectionné. Ce principe d'escamotage appliqué au cylindre tramé 33 de la première installation 3 est illustré aux figures 2A et 2B.Preferably the electronic circuit 7 is also programmed to control the movement of the screened cylinder 33 or 43 from its working position to a retracting position, and vice versa, in synchronism with the reference signal, and according to the status of the tracking sensor that was selected. This retraction principle applied to the screened cylinder 33 of the first installation 3 is illustrated in FIGS. 2A and 2B.

A la figure 2A, le cliché 31 du cylindre porte-cliché 30 est en cours d'impression sur une feuille 1a et le cylindre tramé 33 est en position de travail, et vient s'appliquer tangentiellement au cliché 31. On a représenté en pointillés l'emplacement théorique de la feuille suivante 1'a qui est absente. Lorsque le bord arrière 31b du cliché 31 arrive au niveau du cylindre tramé 33 et que le capteur de repérage 39a ou 39b qui a été sélectionné n'a pas détecté la feuille suivante, le circuit électronique 7 commande l'escamotage du cylindre tramé 33 de manière à l'amener dans la position illustrée à la figure 2B. Si l'on se réfère à la figure 2B, la feuille 1a étant absente, le cylindre tramé 33 n'est pas en contact avec le cliché 31. Au moment où le bord arrière 31b du cliché 31 arrive au niveau du cylindre tramé 33, le circuit électronique 7 commande l'abaissement du cylindre 33 pour l'amener en position de travail, car une nouvelle feuille 1a a été repérée par le capteur de repérage 39a ou 39b qui a été sélectionné. Ce positionnement du cylindre tramé 33 doit être effectué avant que le bord avant 31a du cliché 31 arrive au niveau du cylindre tramé 33. L'escamotage du cylindre tramé, en cas d'absence d'une ou plusieurs feuilles, permet d'éviter un encrage inutile du cliché qui provoquerait une accumulation d'encre, qui peut être préjudiciable à l'impression en ce qu'elle aboutit à des motifs imprimés plus ou moins foncés.In FIG. 2A, the plate 31 of the plate cylinder 30 is being printed on a sheet 1 a and the screened cylinder 33 is in the working position, and is applied tangentially to the plate 31. There is shown in dotted the theoretical location of the next sheet 1 'is absent. When the rear edge 31 b of the plate 31 arrives at the screened cylinder 33 and the location sensor 39 a or 39 b which has been selected has not detected the next sheet, the electronic circuit 7 controls the retraction of the cylinder screened 33 so as to bring it into the position illustrated in FIG. 2B. If one refers to Figure 2B, the sheet 1 a is absent, the anilox roller 33 is not in contact with the plate 31. When the trailing edge 31b of the plate 31 arrives at the anilox roller 33, the electronic circuit 7 controls the lowering of the cylinder 33 to bring it into the working position, because a new sheet 1 a has been identified by the location sensor 39 a or 39 b which has been selected. This positioning of the anilox roller 33 must be performed before the front edge 31a of the plate 31 arrives at the anilox cylinder 33. The retraction of the engraved roller, in the absence of one or more sheets, avoids unnecessary inking of the plate which would cause an accumulation of ink, which can be detrimental to printing in that it results in more or less dark printed patterns.

La ligne d'impression de l'invention présente l'avantage de pouvoir fonctionner avec tout type de clichés, et notamment avec des clichés d'épaisseur variée, sans qu'il y ait nécessité de lui apporter une quelconque modification. De plus, le changement des clichés de la ligne d'impression ne modifie pas la vitesse de rotation des cylindres porte-cliché, et par là-même ne nécessite pas de modification de la cadence d'impression.The printing line of the invention has the advantage of being able to operate with any type of plate, and in particular with plates of varied thickness, without there being any need to make any modification to it. In addition, changing the printing line shots does not change the rotational speed of the printing cylinders, and therefore does not require changing the printing rate.

L'invention n'est pas limitée à la ligne d'impression particulière qui vient d'être décrite mais en couvre toutes les variantes. Les cylindres contre-pression peuvent être remplacés par des poutres fixes, ou être entraînés en rotation par le moteur du système de transfert correspondant. il est également possible que le cylindre porte-cliché de l'une des installations soit équipé d'un codeur délivrant à destination du circuit électronique 7 un signal qui est fonction de la position angulaire dudit cylindre, et qui fait office de signal de référence 6. Dans ce cas, le moteur du cylindre porte-cliché peut être un moteur à courant continu équipé d'un variateur de vitesse, la vitesse de rotation de ce moteur étant réglée préalablement en fonction de la cadence d'impression de la ligne.The invention is not limited to the particular printing line which has just been described but covers all the variants thereof. The back-pressure cylinders can be replaced by fixed beams, or be rotated by the motor of the corresponding transfer system. it is also possible that the plate cylinder of one of the installations is equipped with an encoder delivering destination of the electronic circuit 7 a signal which is a function of the angular position of said cylinder, and which acts as a reference signal 6. In this case, the motor of the plate cylinder can be a DC motor equipped with a variator speed, the speed of rotation of this motor being adjusted beforehand as a function of the printing rate of the line.

Claims (11)

Installation (3,4) pour l'impression feuille à feuille comportant : - un cylindre porte-cliché (30,40) à la périphérie duquel est fixé un cliché (31,41) d'épaisseur Ec, - un système de contre-pression, qui est éventuellement un cylindre contre-pression (35,45) - un cylindre tramé (33,43), - et un système de transfert (36,46) à l'entrée duquel les feuilles (1a) sont introduites une à une et qui amène successivement chaque feuille (1a) jusqu'à la ligne de pincement (38,48) entre le cylindre porte-cliché (30,40) et le cylindre contre-pression (35,45), caractérisée en ce qu'elle comprend en outre : a) trois ou quatre moteurs qui sont indépendants mécaniquement et qui entraînent en rotation respectivement le cylindre porte-cliché (30,40) pour le premier, le cylindre tramé (33,43) pour le deuxième, le système de transfert (36,46) pour le troisième, et éventuellement le cylindre contre-pression (35,45) pour le quatrième, b) et un circuit électronique (7) qui est connecté aux deuxième, troisième et éventuellement quatrième moteurs, qui reçoit en entrée un signal de référence (6) et qui comprend des moyens d'entrée des paramètres de fonctionnement, dont au moins l'épaisseur Ec du cliché (31,41) et la cadence d'impression,
en ce que le premier moteur entraîne en rotation le cylindre porte-cliché (30,40) en synchronisme avec le signal de référence (6), de telle sorte que le cylindre porte-cliché effectue un rotation de 360° à vitesse constante pendant l'intervalle de temps corrrespondant à la cadence d'impression, et en ce que le circuit électronique (7) commande automatiquement la rotation des deuxième, troisième et éventuel quatrième moteurs, à partir du signal de référence (6) et en fonction de l'épaisseur Ec, de telle sorte d'une part que la vitesse linéaire périphérique du cylindre tramé (33,43) soit égale à la vitesse linéaire du cliché (31,41) sur le cylindre porte-cliché (30,40), et d'autre part que la vitesse linéaire du système de transfert (36,46) et éventuellement la vitesse linéaire périphérique du cylindre contre-pression (35,45) soient égales à la vitesse linéaire du cliché (31,41) sur le cylindre porte-cliché (30,40), pendant au moins l'intervalle de temps T₁ où le cliché imprime. Installation (3,4) for sheet-by-sheet printing comprising: - a plate cylinder (30,40) at the periphery of which is fixed a plate (31,41) of thickness E c , - a back pressure system, which is possibly a back pressure cylinder (35,45) - a screened cylinder (33,43), - And a transfer system (36,46) at the entrance of which the sheets (1 a ) are introduced one by one and which successively brings each sheet (1 a ) to the pinch line (38,48) between the plate cylinder (30.40) and the back-pressure cylinder (35.45), characterized in that it further comprises: a) three or four motors which are mechanically independent and which rotate the plate cylinder (30,40) for the first, the screen cylinder (33,43) for the second, the transfer system (36,46) ) for the third, and possibly the back-pressure cylinder (35,45) for the fourth, b) and an electronic circuit (7) which is connected to the second, third and possibly fourth motors, which receives as input a reference signal (6) and which comprises means for inputting operating parameters, at least of which thickness E c of the plate (31.41) and the printing rate,
in that the first motor rotates the plate cylinder (30,40) in synchronism with the reference signal (6), so that the plate cylinder rotates 360 ° at constant speed during l 'time interval corresponding to the printing rate, and in that the electronic circuit (7) automatically controls the rotation of the second, third and possible fourth motors, from the reference signal (6) and according to the thickness E c , so on the one hand that the peripheral linear speed of the screen cylinder (33,43) is equal to the linear speed of the plate (31,41) on the plate cylinder (30,40), and on the other hand that the linear speed of the system of transfer (36,46) and possibly the peripheral linear speed of the back-pressure cylinder (35,45) are equal to the linear speed of the plate (31,41) on the plate cylinder (30,40), for at least the time interval T₁ where the plate prints. Installation selon la revendication 1 caractérisée en ce que le premier moteur entraîne le cylindre porte-cliché avec une vitesse de rotation constante prédéfinie et le cylindre porte-cliché est équipé d'un codeur délivrant, pour le circuit électronique (7), le signal de référence (6) qui est fonction de la position angulaire du cylindre porte-cliché.Installation according to claim 1 characterized in that the first motor drives the plate cylinder with a predefined constant speed of rotation and the plate cylinder is equipped with an encoder delivering, for the electronic circuit (7), the signal reference (6) which is a function of the angular position of the plate cylinder. Installation selon la revendication 1 caractérisée en ce que le premier moteur est connecté au circuit électronique (7) qui reçoit en entrée le signal de référence (6) et qui est apte à contrôler la rotation du premier moteur en synchronisme avec ledit signal.Installation according to claim 1 characterized in that the first motor is connected to the electronic circuit (7) which receives as input the reference signal (6) and which is capable of controlling the rotation of the first motor in synchronism with said signal. Installation selon la revendications 3 caractérisée en ce que le circuit électronique (7) est apte, préalablement au lancement de l'impression feuille à feuille, à contrôler la rotation du premier moteur de manière à amener le cylindre porte-cliché (40) dans une position angulaire initiale qui dépend d'un paramètre de calage prédéfini.Installation according to claims 3 characterized in that the electronic circuit (7) is able, before launching the sheet-by-sheet printing, to control the rotation of the first motor so as to bring the plate cylinder (40) into a initial angular position which depends on a predefined setting parameter. Installation (3) selon l'une quelconque des revendications 1 à 4 caractérisée en ce qu'elle comprend en outre, au niveau du système de transfert (36), au moins un capteur de repérage du passage du bord d'une feuille qui est connecté au circuit électronique (7), et en ce que ledit circuit électronique (7) est en outre apte, en synchronisme avec le signal de référence (6), à contrôler la rotation du troisième moteur, d'une part pendant chaque intervalle de temps T₁ où le cliché (31) imprime, de telle sorte que la vitesse linéaire du système de transfert soit égale à la vitesse linéaire du cliché, et d'autre part pendant chaque intervalle de temps T₂ où le cliché n'imprime pas, de telle sorte que le bord dont on détecte le passage à une distance déterminée de la ligne de pincement (38) arrive au niveau de ladite ligne lorsque le cylindre porte-cliché (40) est dans une position prédéterminée .Installation (3) according to any one of claims 1 to 4 characterized in that it further comprises, at the transfer system (36), at least one sensor for tracking the passage of the edge of a sheet which is connected to the electronic circuit (7), and in that said electronic circuit (7) is further able, in synchronism with the reference signal (6), to control the rotation of the third motor, on the one hand during each interval of time T₁ where the plate (31) prints, so that the linear speed of the transfer system is equal to the linear speed of the plate, and on the other hand during each time interval T₂ where the plate does not print, of such that the edge, the passage of which at a determined distance from the nip (38) is detected, arrives at the level of said line when the plate cylinder (40) is in a predetermined position. Installation selon la revendication 5 caractérisée en ce qu'elle comprend deux capteurs de repérage qui sont disposés au niveau du système de transfert, l'un (39b) pour la détection du bord avant, et l'autre (39a) pour la détection du bord arrière de chaque feuille (1a), et des moyens de sélection de l'un ou l'autre capteurs, qui sont reliés au circuit électronique (7).Installation according to claim 5 characterized in that it comprises two tracking sensors which are arranged at the level of the transfer system, one (39 b ) for the detection of the front edge, and the other (39 a ) for the detection of the trailing edge of each sheet (1 a), and means for selecting one or the other sensors, which are connected to the electronic circuit (7). Installation selon l'une quelconque des revendications 1 à 6 caractérisée en ce qu'elle est équipée d'un dispositif de réglage de la distance axiale du cylindre tramé (33,43) , par rapport au cylindre porte-cliché (30,40), ledit dispositif étant muni d'un cinquième moteur individuel connecté au circuit électronique (7), lequel est apte à contrôler ledit cinquième moteur individuel de manière à amener le cylindre tramé (33,43) jusqu'à une position de travail qui dépend de l'épaisseur Ec du cliché, et dans laquelle il vient s'appliquer précisément sur la surface du cliché (31,41).Installation according to any one of claims 1 to 6 characterized in that it is equipped with a device for adjusting the axial distance of the screened cylinder (33,43), relative to the plate cylinder (30,40) , said device being provided with a fifth individual motor connected to the electronic circuit (7), which is capable of controlling said fifth individual motor so as to bring the screened cylinder (33,43) to a working position which depends on the thickness E c of the plate, and in which it comes to be applied precisely on the surface of the plate (31,41). Installation selon les revendications 5 et 7 caractérisée en ce que le circuit électronique (7) est apte à contrôler la rotation du cinquième moteur individuel de manière à commander le déplacement du cylindre tramé (33,43) de sa position de travail jusqu'à une position d'escamotage et vice versa respectivement chaque fois que le bord de la feuille suivante n'est pas ou est de nouveau détecté, et de façon synchrone avec le signal de référence (6) de manière à assurer ce déplacement pendant que le cylindre tramé est en regard de la zone du porte-cliché dépourvu de cliché.Installation according to claims 5 and 7 characterized in that the electronic circuit (7) is capable of controlling the rotation of the fifth individual motor so as to control the movement of the screened cylinder (33,43) from its working position to a retraction position and vice versa respectively each time the edge of the next sheet is not or is detected again, and synchronously with the reference signal (6) so as to ensure this movement while the screened cylinder is opposite the area of the plate holder without a plate. Installation selon l'une quelconque des revendications 1 à 8 caractérisée en ce qu'elle est équipée d'un dispositif de réglage de la distance entre le système de contre-pression et le cylindre porte-cliché (30,40) du système de contre-pression, ledit dispositif étant muni d'un sixième moteur individuel connecté au circuit électronique (7), qui est apte à en contrôler la rotation de manière à amener le système de contre-pression dans une position de travail qui dépend de l'épaisseur Ec du cliché et de l'épaisseur des feuilles qui doivent être imprimées.Installation according to any one of Claims 1 to 8, characterized in that it is equipped with a device for adjusting the distance between the counter-pressure system and the plate-holding cylinder (30,40) of the counter system. pressure, said device being provided with a sixth individual motor connected to the electronic circuit (7), which is capable of controlling its rotation so as to bring the back-pressure system into a working position which depends on the thickness E c of the plate and the thickness of the sheets to be printed. Ligne d'impression pour impression feuille à feuille multiple caractérisée en ce qu'elle comporte une pluralité d'installations (3,4) visées à l'une quelconque des revendications 1 à 9, dont les cylindres porte-cliché sont identiques et sont équipés de clichés de même épaisseur Ec, et en ce que l'ensemble des moteurs de chaque installation est connecté à un unique circuit électronique (7).Printing line for multi-sheet printing, characterized in that it comprises a plurality of installations (3, 4) referred to in any one of claims 1 to 9, the plate cylinders of which are identical and are fitted with plates of the same thickness E c , and in that all the motors in each installation are connected to a single electronic circuit (7). Ligne d'impression selon la revendication 10 caractérisée en ce qu'elle comporte une installation visée à la revendication 2, et en ce que le signal de référence (6) reçu par le circuit électronique (7) correspond au signal délivré par le codeur du cylindre porte-cliché de ladite installation.Printing line according to claim 10 characterized in that it comprises an installation referred to in claim 2, and in that the reference signal (6) received by the electronic circuit (7) corresponds to the signal delivered by the encoder of the plate cylinder of said installation.
EP94490010A 1993-03-26 1994-03-22 Device for printing one sheet after the other and corresponding printing sheet Expired - Lifetime EP0616886B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR9303707 1993-03-26
FR9303707A FR2702998B1 (en) 1993-03-26 1993-03-26 Installation for sheet-by-sheet printing and corresponding printing line.

Publications (2)

Publication Number Publication Date
EP0616886A1 true EP0616886A1 (en) 1994-09-28
EP0616886B1 EP0616886B1 (en) 1995-06-21

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US (1) US5385091A (en)
EP (1) EP0616886B1 (en)
CN (1) CN1099337A (en)
DE (1) DE69400007T2 (en)
ES (1) ES2076845T3 (en)
FR (1) FR2702998B1 (en)

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DE19510677A1 (en) * 1995-03-27 1996-10-02 Alexander Dipl In Muehlhaeuser Rotary printing machine with round printing head
WO2001034397A1 (en) * 1999-11-07 2001-05-17 Indigo N.V. Tandem printing system with fine paper-position correction
EP1364783A2 (en) * 2002-05-20 2003-11-26 Maria Teresa Cintio High-speed printing machine with flexo printing matrix for sheets transported via a continuous suction belt conveyor
EP1500504A2 (en) 2003-07-24 2005-01-26 Robert Bürkle GmbH Apparatus for printing flat articles produced from wood-fibre material
US6851672B1 (en) 2000-04-18 2005-02-08 Hewlett-Packard Indigo B.V. Sheet transport position and jam monitor
US6912952B1 (en) 1998-05-24 2005-07-05 Hewlett-Packard Indigo B.V. Duplex printing system
EP2085221A1 (en) * 2008-01-29 2009-08-05 Koenig & Bauer AG Drive for a sheet fed printing press
WO2013060416A3 (en) * 2011-10-24 2013-07-25 Bobst Mex Sa Setup method and arrangement for a printing machine
WO2014108324A1 (en) * 2013-01-11 2014-07-17 Bobst Lyon Method of control for controlling a transformation machine, transformation machine and computer program for carrying out such a method of control

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US5615609A (en) * 1995-08-21 1997-04-01 The Lawrence Paper Company System and method for controlling AC motor driven multi-unit printing press
NL1005525C2 (en) * 1997-03-13 1998-09-15 Multi Print Systems M P S B V Printing machine with interchangeable ink applicators.
DE19714402A1 (en) * 1997-04-08 1998-10-15 Lemo Maschb Gmbh Flexo printing machine with several inking units
EP0913254A1 (en) * 1997-07-09 1999-05-06 The Langston Corporation Apparatus for printing corrugated board
JP2000502969A (en) 1997-07-09 2000-03-14 ザ ラングストン コーポレイション Equipment for printing on cardboard
DE19742461C2 (en) * 1997-09-26 2001-05-10 Heidelberger Druckmasch Ag Device for driving a sheet-fed printing machine with a multi-motor drive
US6059705A (en) * 1997-10-17 2000-05-09 United Container Machinery, Inc. Method and apparatus for registering processing heads
US6418847B1 (en) * 1999-10-20 2002-07-16 Ward Holding Company Printing machine with plate thickness compensation
ES2163376B1 (en) * 2000-05-25 2003-02-16 Comexi Sa PERFECTING INTRODUCED IN FLEXOGRAPHIC PRINTER MACHINES.
US6705222B2 (en) * 2001-03-09 2004-03-16 Ward, Inc. Dual registration control system
US8066848B2 (en) * 2007-11-02 2011-11-29 The Procter & Gamble Company Absorbent paper product having printed indicia with a wide color palette
NL2032263B1 (en) * 2022-05-16 2023-11-24 Canon Production Printing Holding Bv Flexographic printing assembly for same-sized plate rollers

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DE4031964A1 (en) * 1990-10-09 1992-04-23 Lehmacher & Sohn Masch Rotary printing machine applying small additional images - has basic block and counter pressure piece moving in opposing directions at same peripheral speed

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19510677A1 (en) * 1995-03-27 1996-10-02 Alexander Dipl In Muehlhaeuser Rotary printing machine with round printing head
US6912952B1 (en) 1998-05-24 2005-07-05 Hewlett-Packard Indigo B.V. Duplex printing system
WO2001034397A1 (en) * 1999-11-07 2001-05-17 Indigo N.V. Tandem printing system with fine paper-position correction
US6823786B1 (en) 1999-11-07 2004-11-30 Hewlett-Packard Indigo B.V. Tandem printing system with fine paper-position correction
US6851672B1 (en) 2000-04-18 2005-02-08 Hewlett-Packard Indigo B.V. Sheet transport position and jam monitor
EP1364783A3 (en) * 2002-05-20 2004-12-15 Maria Teresa Cintio High-speed printing machine with flexo printing matrix for sheets transported via a continuous suction belt conveyor
EP1364783A2 (en) * 2002-05-20 2003-11-26 Maria Teresa Cintio High-speed printing machine with flexo printing matrix for sheets transported via a continuous suction belt conveyor
EP1500504A2 (en) 2003-07-24 2005-01-26 Robert Bürkle GmbH Apparatus for printing flat articles produced from wood-fibre material
EP1500504A3 (en) * 2003-07-24 2008-01-23 Robert Bürkle GmbH Apparatus for printing flat articles produced from wood-fibre material
EP2085221A1 (en) * 2008-01-29 2009-08-05 Koenig & Bauer AG Drive for a sheet fed printing press
WO2013060416A3 (en) * 2011-10-24 2013-07-25 Bobst Mex Sa Setup method and arrangement for a printing machine
US9895873B2 (en) 2011-10-24 2018-02-20 Bobst Mex Sa Adjustment method and arrangement for a printing machine
WO2014108324A1 (en) * 2013-01-11 2014-07-17 Bobst Lyon Method of control for controlling a transformation machine, transformation machine and computer program for carrying out such a method of control
FR3000917A1 (en) * 2013-01-11 2014-07-18 Bobst Lyon CONTROL METHOD FOR CONTROLLING A TRANSFORMING MACHINE, TRANSFORMING MACHINE AND COMPUTER PROGRAM FOR CARRYING OUT SUCH A CONTROL METHOD
US9989953B2 (en) 2013-01-11 2018-06-05 Bobst Lyon Visual interface and control of converting machine operations

Also Published As

Publication number Publication date
FR2702998B1 (en) 1995-06-16
US5385091A (en) 1995-01-31
CN1099337A (en) 1995-03-01
DE69400007T2 (en) 1995-12-14
FR2702998A1 (en) 1994-09-30
EP0616886B1 (en) 1995-06-21
DE69400007D1 (en) 1995-07-27
ES2076845T3 (en) 1995-11-01

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