EP1938972A1 - Offset printing press with adjustment of the cut-off register and corresponding method - Google Patents

Abstract

The press (1) has a control system (25) controlling a passage of paper printing units (7, 9, 11, 13) under pressure configuration. Upper and lower printing groups include a plate cylinder and a print cylinder that are connected with a pressure cylinder. The system controls a paper bandage (3) to be scrolled in a space between the print cylinder and the pressure cylinder. The system controls acceleration of the plate cylinder to modify adjustment of a print-to-cut register between the printing units and a folding machine (23). An independent claim is also included for a method for modifying a print-to-cut register of an offset paper printing press.

Description

• un bâti,
• au moins un groupe d'impression comprenant un cylindre porte-plaque et un cylindre porte-blanchet destiné à coopérer avec un cylindre de pression,
• un mécanisme de support et de déplacement des cylindres grâce auquel l'unité d'impression présente au moins une configuration en-pression, dans laquelle le cylindre porte-blanchet et le cylindre de pression sont appliqués l'un contre l'autre, et une configuration hors-pression, dans laquelle le cylindre porte-blanchet et le cylindre de pression sont écartés l'un de l'autre et délimitent entre eux un espace.

The present invention relates to an offset printing press of the type comprising at least one printing unit of a paper web, a cross-cutting device of the paper web disposed downstream of the printing unit, and the least one control system of the printing unit, the printing unit comprising:

• a frame,
• at least one printing unit comprising a plate cylinder and a blanket cylinder for cooperating with a pressure cylinder,
• a cylinder supporting and moving mechanism by which the printing unit has at least one pressure configuration, in which the blanket cylinder and the pressure cylinder are applied against each other, and a non-pressure configuration, in which the blanket cylinder and the pressure cylinder are spaced from each other and delimit between them a space.

The invention applies, in particular, to shaftless presses, that is to say where the drive of the printing units is provided by respective independent electric motors which are synchronized with each other.

Such an arrangement makes it possible to suppress the common motor and the longitudinal mechanical coupling shaft between the printing units which were used in the state of the art.

In such a press, the cutting device, which usually belongs to a folder, is also provided with a respective independent electric motor.

Such presses are known, particularly documents GB-2 149 149 and EP-699,524 .

As indicated in these documents, the shaftless presses also have advantages related to the settings of the registers, and in particular to the adjustment of the cutting register. This setting can indeed be made without the full-width compensators that were generally interposed between the printing units and the folder.

Since these full-width compensators are eliminated, the adjustment of the cutting register, that is to say of the position of the cross-section with respect to the images printed successively on the strip, is ensured not by modifying the length of the strip between the downstream printing unit and the folder, but by changing the angular positions of the plate cylinders of the printing units.

Thus, during presetting of the press before the execution of a printing job, each plate cylinder is brought into a predetermined angular position making it possible to reach the desired cutting register and thus to ensure that the cross-section is engaged. at the right longitudinal location between all the images successively printed on the paper tape by the printing units.

In these documents, it also corrects the cut register errors that can be detected while the press is in operation and that the paper strip scrolls.

For this purpose, the plate cylinders of the printing units are slowed or accelerated while the paper web is clamped between their blanket cylinders and the corresponding pressure cylinders.

However, such a correction is slow so that the amount of waste paper can be large.

Thus, such a correction of the cutting register can take several minutes if the extent of the correction to be made is important.

This may for example be the case in case of change of path of the paper strip downstream of the printer groups.

An object of the invention is to solve this problem by providing a press of the aforementioned type for changing the setting of the cutting register by limiting the amount of paper wasted.

1. a) passage de l'unité d'impression en configuration hors-pression, la bande de papier défilant alors dans l'espace délimité entre les cylindres porte-blanchet,
2. b) ralentissement ou accélération du cylindre porte-plaque pour modifier le réglage du registre de coupe entre l'unité d'impression et le dispositif de coupe, et
3. c) passage de l'unité d'impression en configuration en-pression.

For this purpose, the subject of the invention is a printing press of the aforementioned type, characterized in that the control system is adapted to control, while the paper web is in scrolling, the execution of steps of:

1. a) passing the printing unit into a non-pressure configuration, the paper strip then traveling in the space defined between the blanket cylinders,
2. b) slowing or accelerating the plate cylinder to change the setting of the cutting register between the printing unit and the cutting device, and
3. c) switching from the printing unit to the pressure configuration.

• le système de pilotage est adapté pour comparer l'amplitude d'une modification du réglage du registre de coupe à effectuer à une valeur seuil et commander, alors que la bande de papier est en défilement et en fonction du résultat de la comparaison, soit l'exécution des étapes a), b) et c), soit l'exécution de l'étape b).
• la presse comprend au moins un capteur de détection de marques de repérage imprimées sur la bande par l'unité d'impression, et le système de pilotage est adapté pour déterminer à partir d'un signal fourni par le capteur de détection une modification du réglage du registre de coupe à effectuer,
• le système de pilotage comprend un dispositif de saisie d'une modification du réglage du registre de coupe à effectuer,
• le cylindre de pression est formé par le cylindre porte-blanchet d'un autre groupe d'impression de l'unité d'impression,
• l'unité d'impression comprend un système d'encrage et un système d'humidification, et le système de pilotage est adapté pour commander l'exécution :
  • entre les étapes a) et b), d'une étape a1) de désactivation des systèmes d'encrage et d'humidification, et
  • entre les étapes b) et c), d'une étape b1) de réactivation des systèmes d'encrage et d'humidification ;
• chaque unité d'impression comprend au moins un moteur électrique d'entraînement respectif distinct du moteur d'entraînement du dispositif de coupe ;
• dans la configuration hors-pression, l'espace est adapté pour permettre à la bande de défiler librement sans toucher les cylindres porte-blanchet ; et
• le dispositif de coupe appartient à une plieuse.

According to particular embodiments, the press may comprise one or more of the following characteristics, taken in isolation or in any technically possible combination:

• the control system is adapted to compare the amplitude of a modification of the setting of the cutting register to be made to a threshold value and to control, while the paper strip is in scrolling and according to the result of the comparison, ie the execution of steps a), b) and c), that is the execution of step b).
• the press comprises at least one registration mark detection sensor printed on the web by the printing unit, and the control system is adapted to determine from a signal provided by the detection sensor a modification of the setting the cut register to perform,
• the control system comprises an input device for a modification of the adjustment of the cutting register to be performed,
• the pressure cylinder is formed by the blanket cylinder of another printing unit of the printing unit,
• the printing unit comprises an inking system and a humidification system, and the control system is adapted to control the execution:
  • between steps a) and b), a step a1) of deactivation of the inking and humidification systems, and
  • between steps b) and c), a step b1) of reactivation of the inking and humidification systems;
• each printing unit comprises at least one respective driving electric motor separate from the driving motor of the cutting device;
• in the non-pressure configuration, the space is adapted to allow the tape to freely move without touching the blanket cylinders; and
• the cutting device belongs to a folder.

1. a) passage de l'unité d'impression en configuration hors-pression, la bande de papier défilant alors dans l'espace délimité entre les cylindres porte-blanchet,
2. b) ralentissement ou accélération du cylindre porte-plaque pour modifier le réglage du registre de coupe entre l'unité d'impression et le dispositif de coupe, et
3. c) passage de l'unité d'impression en configuration en-pression.

The invention also has a method for modifying the cutting register of a printing press, characterized in that the printing press is a press as defined above and in that the method comprises steps of:

1. a) passing the printing unit into a non-pressure configuration, the paper strip then traveling in the space defined between the blanket cylinders,
2. b) slowing or accelerating the plate cylinder to change the setting of the cutting register between the printing unit and the cutting device, and
3. c) switching from the printing unit to the pressure configuration.

• le procédé comprend une étape préalable de comparaison de l'amplitude d'une modification du réglage du registre de coupe est en défilement et en fonction du résultat de la comparaison, soit l'exécution des étapes a), b) et c), soit l'exécution de l'étape b) ; et
• l'unité d'impression de la presse d'impression comprend un système d'encrage et un système d'humidification, et le procédé comprend :
  • entre les étapes a) et b), une étape a1) de désactivation des systèmes d'encrage et d'humidification, et
  • entre les étapes b) et c), une étape b1) de réactivation des systèmes d'encrage et d'humidification.

According to particular embodiments, the method may comprise one or more of the following characteristics, taken in isolation or in any technically possible combination:

• the method comprises a preliminary step of comparing the amplitude of a modification of the setting of the cutting register is scrolling and depending on the result of the comparison, or the execution of steps a), b) and c), or the execution of step b); and
• the printing unit of the printing press comprises an inking system and a humidification system, and the method comprises:
  • between steps a) and b), a step a1) of deactivation of the inking and humidification systems, and
  • between steps b) and c), a step b1) of reactivation of the inking and humidification systems.

• la figure 1 est une vue schématique d'une presse d'impression offset selon l'invention,
• la figure 2 est une vue schématique d'une unité d'impression de la presse de la figure 1, l'unité d'impression étant en configuration en-pression,
• la figure 3 est une vue analogue à la figure 2, l'unité d'impression étant en configuration hors-pression, et
• la figure 4 est un ordinogramme illustrant les étapes d'un procédé de correction du registre de coupe mis en oeuvre par la presse de la figure 1.

The invention will be better understood on reading the description which follows, given solely by way of example, and with reference to the appended drawings, in which:

• the figure 1 is a schematic view of an offset printing press according to the invention,
• the figure 2 is a schematic view of a printing unit of the press of the figure 1 the printing unit being in an in-press configuration,
• the figure 3 is a view similar to the figure 2 the printing unit being in an off-press configuration, and
• the figure 4 is a flow chart illustrating the steps of a method of correcting the cutting register implemented by the press of the figure 1 .

The figure 1 illustrates an offset printing press 1 which comprises mainly, and successively along the running direction of the web 3, a unwinder 5, printing units 7, 9, 11 and 13, partial width compensators 15 and 17 for adjusting the respective cutting registers of strips 19 and 21 cut longitudinally in the strip 3, and a folder 23.

In the example shown, the press 1 does not include a dryer / cooler, but this may be the case in some variants.

In some variants also, the press 1 may not include partial width compensators 15 and 17.

In the example shown also, the press 1 comprises four printing units 7, 9, 11 and 13, but this number may be different, especially if the press is a so-called Auto Transfer press (registered trademark).

Recall that in such a press, some printing units can perform a print job, while others can be prepared for a subsequent print job.

The cylinders of the printing units 7, 9, 11 and 13, the compensators 19 and 21 and the folder 23, which are in contact with the band 3 and which are motorized, drive the paper strip 3 to it scrolls from the unwinder 5 to the folder 23.

The press may also include other tape drive devices 3, such as rollers.

All the functional elements mentioned above, and in particular the printing units 7, 9, 11 and 13, are controlled by a computer control system 25 which is on the one hand connected to these various functional elements and which is other part connected, in the example shown, to a sensor 27. This sensor 27 is a marking mark detection sensor printed on the strip 3 by the units 7, 9, 11 and 13 to regulate the registers, as this will be described later.

In some variants, the press 1 may not include a sensor 27.

The structures of the printing units of the units 7, 9, 11 and 13 are similar and only that of the unit 7 will be described later with reference to the Figures 2 and 3 .

The printing unit 7 comprises two printing groups, namely an upper printing unit 29 and a lower printing unit 31. Each group 29, 31 comprises a plate cylinder 33, which can carry one or several plates and a blanket cylinder 35, which can carry one or more blankets. The blanket cylinder 35 of the lower printing unit 31 acts as a pressure cylinder for the upper printing unit 29 and vice versa. The printing unit 7 is therefore a blanket against blanket printing unit.

Preferably, the press 1 is a shaftless press, that is to say that all the printing units 7, 9, 11 and 13 and the folder 23 each have at least one respective independent electric drive motor 37 .

Thus, each printing unit can have a single respective electric motor, which drives the two printing units 29 and 31. It is also possible to provide a respective drive motor for each printing unit 29 and 31. In this case, for each printing unit, the motor can, for example, drive the blanket cylinder 35 through the plate cylinder 33 of the printing unit in question.

It is furthermore possible to provide a respective drive motor for each cylinder 33, 35 of each printing unit 29, 31.

More generally, all the drive modes of the printing units used in the shaftless presses can be used here.

The printing unit 7 of the Figures 2 and 3 comprises a mechanism 39 for supporting and moving the cylinders 33 and 35, which mechanism 39 is carried by the frame 41 of the unit 7. Typically, this frame 41 comprises two side walls between which the plate cylinders 33 and holder blanket 35 are arranged.

In the example shown, the displacement mechanism 39 comprises arms 43 for receiving the plate cylinders 33 and arms 45 for receiving the blanket cylinders 35. An arm 43 is disposed at each end of a cylinder 33 and an arm 45 is disposed at each end of a cylinder 35. The cylinders 33 and 35 can be journalled in the arms 43 and 45 about their axes in the arms 43 and 45.

The arms 43 and 45 are hinged to the frame 41 to enable them to pivot relative to the frame parallel to the axes of the plate cylinders 33 and blanket holder 35.

Furthermore, the displacement mechanism 39 comprises actuators, for example pneumatic cylinders, for manipulating the arms 43 and 45.

Thanks to the support and displacement mechanism 39, the printing unit 7 has an in-press configuration illustrated by the figure 2 and at least one off-pressure configuration illustrated by the figure 3 .

In the pressurized configuration, the plate cylinders 33 and the blanket holder 35 are pressed against each other and the paper web 3 can thus be clamped between the two blanket cylinders 35 to be printed.

In the pressureless configuration, the printing units 29 and 31 have been moved so that the blanket cylinders 35 are spaced from each other and delimit between them a space 47 in which the band 3 can pass. freely. In some variants, this space 47 is large enough for the strip 3 to pass through without touching the blanket cylinders 35. However, it will be observed that this feature is not essential.

To achieve this configuration, the upper arms 43 and 45 have for example pivoted upwards and the lower arms 43 and 45 have for example pivoted downwards.

In the non-pressure configuration shown, the plate cylinder 33 and the blanket cylinder 35 of the same printing unit are in contact with each other, but this is not necessarily the case. Thus, the printing unit 7 may also have in addition to or in place of the off-pressure configuration of the figure 3 , out-of-pressure configurations in which the plate cylinders 33 and blanket carriers 35 of groups 29 and 31 are spaced from each other. Similarly, the mechanism 39 for supporting and moving cylinders 33 and 35 may have a structure other than that described above and can for example, allow a passage from one configuration to another by moving only some of the cylinders.

Also conventionally, an inking system 49 and a humidification system 51 are associated with each printing unit 29, 31. For the sake of simplification, such systems 49 and 51 have only been shown for the group lower print 31 on the figure 2 .

All the functional equipment of a printing unit, such as inking systems 49, humidification system 51, the support and displacement mechanism 39 and the drive motor (s) 37 are controlled by the steering system 25.

In conventional manner, during printing, the units 7, 9, 11 and 13 are in the pressure configuration. The cylinders of the printing units 29 and 31 are rotated about their respective axes and the web 3 is scrolled. The plates carried by the plate cylinders 33 of the printing units 7, 9, 11 and 13 are moistened and then inked by the inking systems 49 and humidification 51. These plates transfer the ink from their printers to the blankets carried by the cylinders 35, which in turn decal the ink on the strip 3 which is thus printed on both sides. Thus, the blanket cylinders 35 each print, because of their rotation about their respective axes, successively the same image on the strip 3.

After the printing unit 13, the paper web 3 is cut longitudinally to form ribbons 19 and 21 of partial widths. These strips 19 and 21 are, in the example shown, superimposed and cut transversely in the folder 23 between the successive images printed on the strip 3.

During printing, the sensor 27 transmits detection mark detection signals printed on the strip 3 by the units 7, 9, 11 and 13. From these signals, and in a conventional manner, the control system 25 detects possible cutting register and circumferential register errors, that is to say the longitudinal component of the color register. The system corrects these register errors by increasing or decreasing the drive speeds of the plate cylinders 33 of the cylinders of the units 7, 9, 11 and 13.

The system 25 thus implements regulating loops of cutting and circumferential registers.

The compensators 15 and 17 furthermore make it possible to adjust the cutting register of each of the ribbons 19 and 21. Indeed, these registers can not be adjusted independently of one another by rotation of the cylinders of the printing units 7, 9, 11 and 13.

While the band 3 is scrolling, it is possible that, following a change of work, that is to say products to print, or the path of the band 3, correction of the cut register is necessary.

On the figure 1 only one paper web path 3 has been shown. In practice, however, the press 1 may comprise, in addition to the folder 23, other cutting devices or additional modules, such as a perforation group, a subculture group, etc.

The band 3 can then borrow conventionally one of several paths depending on the elements to be crossed or bypass.

In case of modification of the path of the band 3, the correction of the cutting register to be performed may be important. This correction will be ensured by a slowdown or a temporary acceleration of the plate cylinders 33 of the printing units 7, 9, 11 and 13.

The operator may also be required to initiate a modification of the setting of the cutting register by acceleration or deceleration of the cylinders of the printing units 7, 9, 11 and 13, for example if he visually detects a register error.

In each of these two examples, and in order to trigger the modification of the adjustment of the cutting register, the operator actuates an input device of the cutting register modification to be performed, for example a key of a console 53 of the system 25 .

The system 25 then controls the execution of the method illustrated by the flow chart of the figure 4 .

In a first step 55, the amplitude of the requested modification is compared with a threshold value. If the amplitude of the requested change is less than this threshold value then step 57 is performed.

This is a conventional step of modifying the cutting register, performed by acceleration or deceleration of the cylinders of printing units 7, 9, 11 to 13, and in particular plate cylinders 33. The paper strip 3 is therefore always pinched between the blanket cylinders 35 and continues to scroll, as when printing.

If, on the other hand, the amplitude of the requested change is greater than the threshold value, which will be the case, for example, during a change of band path 3, steps 61, 63, 65, 67 and 69 are performed.

In step 61, the control loops of the cut register and the circumferential register are deactivated.

In step 63, the inking 49 and fountain 51 are deactivated and then the printing units 7, 9, 11 and 13 go into an off-press configuration. The paper web 3 is no longer pinched between the blanket cylinders 35.

In step 65, the correction of the cutting register is performed by slowing down or accelerating the cylinders of the printing units, and in particular the plate cylinders 33. The strip 3 no longer being in contact with the blanket cylinders 35 , this slowing down or this acceleration has no effect on the paper web 3. The slowing down or the acceleration can be much greater than in step 57 or in the state of the art, without risking for as much to break the band 3 or without risk of causing a jam in the folder 23. The actual modification step 65 of the cut register can therefore be very short, even for a high amplitude change.

In step 67, the printing units 7, 9, 11 and 13 are put back into the pressure configuration and the inking 49 and wetting 51 systems are reactivated.

In step 69, the control loops of the various registers are reactivated.

Thus, when a large correction of the cutting register is requested, this correction is performed while the printing units are in the non-pressure configuration, which makes it possible to reduce the time necessary to make this correction, and which limits So the paper waste.

Such a method may advantageously be implemented on presses 1 which are not adapted to ensure a pre-adjustment of the cutting register and / or which do not provide regulation of the cutting register.

In general, steps 63 and 67 do not necessarily imply activation and deactivation of inking 49 and wetting systems 51.

Similarly, the printing units do not necessarily have the structure described above and may comprise a number of printing group (s) different from that described above, possibly arranged around a central pressure cylinder and common . It can thus be structures in Y, U, H, ....

In general, the folder 23 may for example be replaced by a simple cutting device.

In addition, the amplitude of a cutting register correction to be performed can be, in certain variants, determined automatically from a signal supplied by the sensor 27.

Claims (12)

Offset printing press (1) of the type comprising at least one paper strip printing unit (3, 7, 9, 11, 13), a paper web cross cutting device (23) (3) disposed downstream of the printing unit, and at least one control system (25) of the printing unit, the printing unit (7, 9, 11, 13) comprising: a frame (41), at least one printing unit (29, 31) comprising a plate cylinder (33) and a blanket cylinder (35) intended to cooperate with a pressure cylinder (35), a mechanism (39) for supporting and moving the cylinders (33, 35) by which the printing unit (7, 9, 11, 13) has at least one pressure configuration, in which the cylinder the blanket (35) and the pressure cylinder (35) are applied against each other, and an off-pressure configuration, in which the blanket cylinder (35) and the pressure cylinder are spaced apart. the other and delimit between them a space (47), characterized in that the control system (25) is adapted to control, while the paper web (3) is scrolling, the execution of steps of: a) passing the printing unit (7, 9, 11, 13) in an off-press configuration, the paper web (3) then traveling in the space (47) delimited between the blanket cylinder (35); ) and the pressure cylinder (35), b) slowing or accelerating the plate cylinder (33) to change the setting of the cutting register between the printing unit (7, 9, 11, 13) and the cutting device (23), c) passing the printing unit (7, 9, 11, 13) in pressurized configuration. Press according to claim 1, wherein the control system (25) is adapted to compare the amplitude of a modification of the setting of the cutting register to be made to a threshold value and to control, while the paper web (3) is scrolling and depending on the result of the comparison, the execution of steps a), b) and c), or the execution of step b). A press according to claim 1 or 2, the press comprising at least one registration mark detection sensor (27) printed on the web (3) by the printing unit (7, 9, 11, 13), and the control system (25) being adapted to determine from a signal provided by the detection sensor (27) a modification of the adjustment of the cutting register to be performed. Press according to one of the preceding claims, wherein the control system (25) comprises a device for capturing a modification of the adjustment of the cutting register to be performed. Press according to one of the preceding claims, wherein the pressure cylinder (35) is formed by the blanket cylinder (35) of another printing unit (31) of the printing unit. Press according to one of the preceding claims, wherein each printing unit (7, 9, 11, 13) comprises an inking system (49) and a humidification system (51), and in which the printing system control (25) is adapted to control the execution: between steps a) and b), a step a1) of deactivation of the inking (49) and humidification (51) systems, and - Between steps b) and c), a step b1) reactivation of the inking systems (49) and humidification (51). Press according to one of the preceding claims, wherein each printing unit (7, 9, 11, 13) comprises at least one respective electric drive motor (37) separate from the driving motor of the cutting device (23). ). Press according to claim 7, wherein, in the non-pressure configuration, the space (47) is adapted to allow the web (3) to move freely without touching the blanket cylinder (35) and the pressure cylinder (35). Press according to one of the preceding claims, wherein the cutting device belongs to a folder (23). A method of modifying the cutting register of a printing press, characterized in that the printing press is a press according to one of the preceding claims and in that the method comprises steps of: a) passing the printing unit (7, 9, 11, 13) in an off-press configuration, the paper web (3) then traveling in the space (47) delimited between the blanket cylinder (35); ) and the pressure cylinder (35), b) slowing or accelerating the plate cylinder (33) to change the setting of the cutting register between the printing unit (7, 9, 11, 13) and the cutting device (23), c) passing the printing unit (7, 9, 11, 13) in pressurized configuration. Method according to claim 10, the method comprising a preliminary step of comparing the amplitude of a modification of the setting of the cutting register to be made to a threshold value in order to control, while the paper strip (3) is in scrolling and depending on the result of the comparison, the execution of steps a), b) and c), or the execution of step b). A method according to claim 10 or 11, wherein each printing unit (7, 9, 11, 13) of the printing press comprises an inking system (49) and a humidification system (51), and wherein the process comprises: between steps a) and b), a step a1) of deactivation of the inking (49) and wetting (51) systems, and - Between steps b) and c), a step b1) of reactivation of the inking systems (49) and humidification (51).

Images