JPH04224946A - Method and device for correcting printing image located slantingly - Google Patents

Abstract

PURPOSE: To obtain a method for bringing all print images to accurate positions by entirely inclining a sheet again straightly after passing printing units or a value obtained from an inclined position of the shet and an angular deviation of the print image of next printing unit. CONSTITUTION: In the case of adjusting a printing machine having four printing units, a sheet B is straightly supplied at the first unit. At a point I, the sheet occupies an inclined position, which is needed to correct an amount of a distance 2X. Thus, a sheet conveying drum 4 is moved upward at an amount of a distance (x). At point II, it must be corrected by a valu of the distance 2y to a reverse side, and hence an additional correction of the distance (y) is superposed, and the drum 4 is adjusted by total amount (z). At point III, i.e., at the third unit, the sheet is not adjusted to be inclined. Accordingly, the drum 4 is moved above by the distance (y). Thus, an online correction is executed.

Description

[Detailed description of the invention]

0001

FIELD OF INDUSTRIAL APPLICATION The present invention relates to a method for correcting angular deviations during the printing of printed images in a multicolor sheet-fed rotary printing machine, the invention being directed to A type in which the sheet transport drum is tilted and the sheet transport drum is inclined with respect to the cylinder means for guiding the sheet during transfer from the sheet transport drum to an adjacent cylinder means for guiding the sheet, and multicolor printing sheets. A device for correcting angular deviations during printing of printed images in a paper rotary printing press, comprising at least three printing sections and a sheet transport drum arranged between the printing sections, One end of the sheet transport drum can be pivoted by means of an inclination adjustment device and has a registration adjustment device for circumferential and lateral registration adjustment on the plate cylinders of the printing section. .

0002

BACKGROUND OF THE INVENTION A device of the above type is known from German Patent Application No. 465 246. When printing multicolored print images on one sheet of paper, it is of great importance to bring the individual, differently colored partial images into exact alignment with one another. For this purpose, as an auxiliary means for correction, devices are used which move the partial images in the circumferential and axial direction of the printing cylinder. A particular problem is that position errors occur due to the rotation of the partial images in the plane relative to the target position. Various attempts have been made to eliminate positional errors of this type by tilting the printing cylinders involved in transporting the printed image relative to each other. This is attempted in offset printing by tilting the plate cylinder. The printing plate is then exclusively developed in a helical manner relative to the blanket cylinder, with the leading and trailing edges lying straight, but with the trailing edge moving laterally. Attempts have therefore been made to rotate the printing plate along the printing cylinder in the plane of extension of the printing plate. This can be done manually or automatically using a plate tensioning device. However, in this case a significantly greater outlay is required for the mounting and control of the printing plate tensioning device. In particular, the operation process is complicated. This is because, in order to tilt, the printing plate must first be relaxed and, after tilting, must be accurately tightened again in its new position. Automation requires complex devices for energy supply and adjustment of the plate tensioning device of the plate cylinder. Such equipment is expensive and prone to errors for continuous operation in practice.

Another arrangement for eliminating the problem is described in German Patent Application No. 465 246. In this case, several printing stations are arranged one after the other in a printing press, and the printing press operates in this case in the gravure printing process. In gravure printing, the printed image is formed by erosion within the plate cylinder. Misalignment of the printed image relative to the plate cylinder is therefore eliminated. In this case as well, the printed image will be tilted. It has therefore been proposed to adapt the position of the sheet to be printed to the position of the printing image on the forme cylinder. This is achieved by adjusting the axis of the sheet transfer drum obliquely relative to the forme cylinder. Such diagonal adjustments can be made both vertically and horizontally. By means of the oblique adjustment, the printed image of a printing unit and the sheet are brought into alignment with each other, so that the printed image is printed in a plane in a precise position relative to the rotational position. The disadvantage of this method is that the circumferential and lateral positions necessarily vary. This is not taken into account in the method. A further disadvantage is that the sheets run through the press at an angle,
With the exception of chance, therefore, registration errors inevitably occur when printing in the next printing section. It is not clear how to take preventive measures against such misregistration.

[0004] Furthermore, the Federal Republic of Germany Patent Application No. 34
In the sheet-processing printing machine known from DE 00652A1, three sheet-guiding cylinders are arranged approximately along a plane in the sheet transport path. In order to correct the skew position of the printed image, an intermediate cylinder, called a correction cylinder, is raised or lowered at one end. This results in a tilting of the sheet conveyed between the first cylinder and the third cylinder by an amount twice as large as the displacement of the cylinder end. The first cylinder and the third cylinder each cooperate with a printing section, in which case the first cylinder receives sheets from the first printing section and the third cylinder receives sheets. The second one is tilted at the desired angle.
Hand it over to the printing department.

[0005] In such printing machines, high construction costs are required in order to tilt the sheets. The additional sheet transfer required at the four locations reduces the operating efficiency of the printing press. Furthermore, no indication is given of how the method is carried out in printing presses with more than two printing stations. This means can only be used on two-color printing machines.

[0006]

SUMMARY OF THE INVENTION It is an object of the invention to improve the method and device of the type mentioned at the outset so that even in multicolor printing presses with more than two printing stations the position of all printed images can be maintained. The purpose of the present invention is to make it possible to take this into account when adjusting diagonal register. For this reason, it is desirable to mutually consider the influence of diagonal register adjustment on circumferential register and lateral register as well as the relative positions of different partial images within the printed parts located in front and behind.

[0007]

In order to achieve the above object, the method of the present invention comprises either straightening the sheet again after passing through each printing section or adjusting the skewed position of the sheet for the next printing. The whole is tilted by a value determined from the angular deviation of the printed image of the copy. Advantageously, an adaptation of the sheet position is carried out during transport through the printing machine on the basis of the definition of the relative positions of the print images, so that all print images are placed in the correct position. In order to carry out the method according to the invention, it is provided that the diagonal register adjustment device is provided with a control device for driving the adjustment motor, and the control devices are connected to each other and are connected to each printing plate or printing plate. It is connected to a storage device for receiving position data of the image, and register adjustment devices for circumferential and lateral register adjustment are each connected to a control device via a correction unit.

[0008]

Effects of the Invention: Due to the effects of the printing process on the paper that cause local variations in the relative position of the printed image, individual corrections at any point on the printing machine can be made without causing misregistration of subsequent prints. It will be done. Additionally, diagonal register adjustments do not affect circumferential and lateral registers.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A printing press, for example a sheet-fed offset printing press, comprises a plurality of printing sections, as shown in FIG. Each printing part is 2
They are connected to each other by a sheet transport drum 4 arranged between two impression cylinders 3. During the printing process of sheets,
Depending on the relative position on the forme cylinder 1, the print image is transferred via the blanket cylinder 2 onto the sheet on the associated impression cylinder 3. Registration adjustment device 5 for circumferential and lateral registration for precise registration, i.e. alignment, up to precise superimposition of the printed images
is provided. Furthermore, a tilt register adjustment takes place on the sheet transport drum 4, so that the sheets are received and delivered obliquely during transport. For adjustment of the printing machine up to the actual printing, it is necessary to align the printed images of the different printing units with each other. For this purpose, a test print is carried out in the starting state of the printing machine, by means of which the mutual position of the different printed images is checked with respect to one another. Based on other known techniques, it is also possible to detect the position of the printing plate in the printing station and to ascertain the relative position with a suitable data processing device. In this case, the influence of paper in the printing process is not taken into account. Once the position data of the printing images are obtained relative to each other, the printing plates or printing cylinders of the different printing stations are adjusted laterally and circumferentially accordingly.

The angular position in which the individual print images are located is ascertained, and the sheets of each printing station are aligned accordingly using the oblique register adjustment devices 6, 7, 8.

This takes place for the first printing station by means of a known adjustment device 9 at the front end of the feeder 10. For subsequent printing stations, the new required tilt position is determined based on the actual position of the sheet obtained by the tilt position of the respective sheet transport drum 4 and the tilt position of the printing image on the forme cylinder 1. is required. In this case, the required tilt position for the measured position data of the respective printing plate is related to the actual position of the sheet from the previous printing station. In the case of a tilt adjustment such as that carried out by displacement of the sheet transport drum 4, the pivot point is located in the area of the leading edge of the sheet. This has an effect on the circumferential and lateral register of the print. Such influences are calculated from the geometry of the printing section and are used for circumferential and lateral register correction.

The control circuit of the device required for diagonal register adjustment will be explained with reference to FIG. A diagonal register adjustment device 6, 7, 8 is provided on the sheet transport drum 4 for each printing station and is connected to a control device 11, 12, 13. Control device 1
1, 12 and 13 are assigned a storage device 14, which storage device contains the position data obtained by detecting the inclination position of the individual printing plates. The control devices 11, 12, and 13 are connected to each other, and a storage device 14 and a storage device 15 are connected to each other.
The storage device 15 detects the front cover inclination adjustment position. Furthermore, each control device 11, 12, 13 is respectively connected to a respective register adjustment device 5 for circumferential register and lateral register.

FIG. 2 shows how the tilt adjustment of the sheet on the cylinder or drum that guides the sheet is produced. The axis T of the sheet transport drum 4 is normally arranged somewhat below the joining plane E which passes through the axis A of the impression cylinders 3.1, 3.2. To make the drawing easier to read, the cross sections of the impression cylinders 3.1, 3.2 and the sheet transport drum 4 are shown in one horizontal plane. Sheet B is placed on the first impression cylinder 3.1
The upper part has reached the transfer point to the sheet transport drum 4. The reference position of the sheet transport drum is indicated in dash-dotted lines in relation to one end. The adjustment plane V is indicated by a double arrow. Upon movement of the axis T over a distance X towards the downwardly inclined transfer position, the receiving edge of the sheet B is displaced rearwardly by a distance X from the reference position of the sheet transport drum 4. This is indicated below the connection plane E by the dash-dotted horizontal transfer line. When the sheet transport drum 4 rotates, the sheets B are transported by a distance X. Sheet transport drum is 180
°Distance X from the reference delivery position on the other side after rotation
, the displacement increases to 2X on the adjustment side for the position of the second impression cylinder 3.2. For example, distance 2X
In order to correct the tilt position by an amount of , it is only necessary to move the sheet transport drum 4 by a distance X. Of course, all such conditions are associated with a unilateral displacement of the sheet transport drum 4, and also apply to a correction of the adjustment plane V in both directions, with the upward displacement adjustment being related to the adjustment side in the sheet running direction. The tilt correction and the downward displacement adjustment result in a tilt correction on the adjustment side opposite to the direction of sheet travel.

FIG. 3 shows an exemplary embodiment of the adjustment of a printing machine with four printing stations. The position of the supplied sheet B is shown in this case by a solid line, and the printed image associated with the sheet is shown by a dash-dotted line. Sheets B are fed straight into the first printing station. This is because the printed image P is not tilted there. At point I, the sheet occupies a tilted position, which requires a correction in the amount of distance 2X. For this purpose, the sheet transport drum 4 in question must be moved upwards by a distance X. This means that in the next printing station a corresponding correction in the opposite direction of the amount of distance X of the sheet and correspondingly of the distance need to be brought about. At point II, the distance to the opposite side is 2y
Since a correction has to be made in the amount of distance y, an additional return adjustment of the amount of distance y is superimposed, and finally an adjustment of the total amount z of distance x+distance y of the sheet transport drum 4 in question. At point III, ie in the third printing station, the sheets do not have to be tilted. This is because the printed image is precisely located here. In other words, only the distance 2y caused by the previous print portion needs to be removed. The sheet transport drum 4 is therefore moved upwards by a distance y.

Based on the adjustment process carried out as described above,
All printing images are matched taking into account the adjustment of the sheet in the case of a tilting of the printing plate or of the printing image formed on the printing plate. If a deviation in the relative position of the printed image occurs during the actual printing, the printing process can be easily controlled.
Online corrections will be made.

The control device 11 of the diagonal register adjustment device 6 is shown in FIG.
It is shown in detail in . The control devices 12, 13 are designed accordingly.

The control device 11 has an actual value input section 16 and a setpoint value input section 17. Actual value input 16 is connected to a preceding control device or zero adjustment device or, in the exemplary embodiment, to a storage device 15 for the tilt position of the front cover. The target value input section 17 is connected to a storage device 14 for position data of the print images of the respective printing section. A conversion unit 18 is connected behind the target value input section 17, and the conversion unit calculates the required tilt position from the position data of the print image. This tilt position data is passed within the control device 11 to an adder 19, which is connected to the actual value input 16 of the control device 11. Addition device 19 generates adjustment commands for the necessary correction values for the respective printing section. This adjustment command is evaluated accordingly in the second conversion unit 20 and passed to the actual value output 21 . From the actual value output 21, the data are passed to the diagonal register adjustment device 6 of the first sheet transport drum 4, to the correction value unit 22 for the register adjustment device 5, and to the control device 12 of the next printing station. The data are then further processed accordingly.

As is clear from the circuit diagrams of FIGS. 1 and 4,
The adjusting device consists of an adjusting eccentric, an adjusting gear for the cylinder journal of the sheet transport drum 4, a motor control and a position value storage for the setpoint and actual values of the register adjusting device. The setpoint value and actual value are associated by means of evaluation electronics for converting and adding adjustment values. The entire device is simple to construct and can be implemented easily afterwards.

FIG. 5 shows a mechanical transmission for carrying out the above-mentioned continuous adjustment. A first eccentric 24 and a second eccentric 25 are attached to the journal 23 of each sheet transport drum 4.
are located inside and outside each other and are supported. The first eccentric 24 has a drive lever 26 which is connected to a drive 27 which can be driven by a motor or which can be operated manually. The drive 27 is fixed to the frame in the first printing section, but is connected to the drive lever 28 of the second eccentric 25 in the subsequent printing section. The second eccentric body 25 is provided with a drive lever 30, and the drive part 31 of the drive lever is connected to the drive lever 26 of the first eccentric body 24.
is supported by When adjusting the first eccentric body 24,
The second eccentric 25 is adjusted together. Subsequent corrections of the printing section are effected by actuation of the drive 31 of the second eccentric 25. The return of the corrected values for the next printing section is automatically brought about by a reverse movement of the drive levers 26 and 28. This is because the drive lever 28, which is connected to the drive lever 26 of the next printing station, carries out the same adjustment movement in the opposite direction.

[Brief explanation of the drawing]

FIG. 1: Schematic diagram of a printing machine according to the invention

[Figure 2] Schematic diagram of the principle of adjusting the inclination of sheets by adjusting the inclination of the sheet transport drum

[Figure 3] Development principle diagram of diagonal register adjustment by sheet tilt adjustment

[Figure 4] Circuit diagram of the control device of the diagonal register adjustment device

[Figure 5]
Mechanical control transmission side view

[Explanation of symbols]

1 plate cylinder, 2 blanket cylinder, 3 impression cylinder,
4 sheet conveyance drum, 5 register adjustment device,
6, 7, 8, diagonal register adjustment device, 9 adjustment device, 11, 12, 13 control device, 14,
15 storage device, 16 actual value input section, 1
7 target value input section, 18 conversion unit, 19
Addition device, 20 Conversion unit, 21 Actual value output section, 22 Correction value unit, 23
journal, 24, 25 eccentric body, 26 drive lever, 27 drive section, 28 drive lever, 30 drive lever, 31 drive section

Claims (5)

[Claims] 1. A method for correcting angular deviations during printing of printed images in a multicolor sheet-fed rotary printing press, comprising:
The sheet is tilted before it passes through the printing section and the sheet transport drum is tilted against the cylinder means for guiding the sheet during transfer from the sheet transport drum to the adjacent cylinder means for guiding the sheet. In the case of tilting type, the sheet is placed in each printing section (1
, 2, 3) or straighten again after passing through the sheet (B) and the next printing section (1, 2, 3).
A method for correcting an obliquely located printed image, characterized by tilting the entire printed image by a value determined from the angular deviation of the printed image. 2. The position of the printing plate or the printing image is determined in relation to the rotational position in the extension plane of the printing image, with the sheet transport drum being inclined relative to the impression cylinder, and the position data being converted from a zero value. Starting from the sheet transport drum (4), it is converted into an adjustment value as a correction value for the inclination of the sheet transport drum (4) and is
, 3) from the new position defined by the first modification value of the sheet (B) in relation to the subsequent printing units (1, 2, 3)
), the resulting tilt position of the sheet transport drum of
determining a new adjustment value as a return adjustment value on the basis of consideration of the correction value known from , and transmitting it to the oblique register adjustment device (6, 7, 8) as an adjustment value for the inclination of the sheet transport drum (4); 2. The method as claimed in claim 1, wherein the circumferential and lateral displacements due to the tilted position are then determined and sent as correction values to a register adjustment device (5) for circumferential and lateral register adjustment. 3. A device for correcting angular deviations during printing of printed images in a multicolor sheet-fed rotary printing press, comprising:
It has at least three printing stations and a sheet transport drum arranged between the printing stations, one end of which can be pivoted by means of a tilt adjustment device, and a plate cylinder of the printing station. In the type having a register adjustment device for circumferential register adjustment and lateral register adjustment at the diagonal register adjustment device (6, 7, 8), a control device (11 , 12, 13) are provided, the control devices (11, 12, 13) being connected to each other and to a storage device (14) for receiving position data of the respective printing plate or printed image. The register adjustment device (5) for circumferential register adjustment and lateral register adjustment is connected to the control device (11, 1) via the correction unit (22), respectively.
2, 13) for the correction of obliquely located printed images. 4. The control device (11, 12, 13) has a setpoint value input (17) for the position data, an actual value input (16) for the adjustment data of the preceding printing station, and the respective printing Actual value output (21) for the adjustment data of the section
The target value input section (17) is equipped with a conversion unit (
18) is assigned, an addition unit (19) is assigned to the output of the conversion unit (18) and the actual value input (16), and the output of the addition unit (19) is connected to another conversion unit ( 20) to the actual value output, the setpoint value input (17) is connected to the storage device (14) for position data, and the actual value input (16) is connected to the preceding control device ( 15, 11, 12) or the actual value input part of the control device (12, 13) of the subsequent printing section, which is connected to the actual value output part of the zero adjustment device, and the actual value output part is connected to the actual value output part of the zero adjustment device, the diagonal register adjustment device (6) 4. The device according to claim 3, wherein the device is connected to an actual value input of the register adjustment device (5) and to an actual value input of the correction unit (22) of the register adjustment device (5). 5. A device for correcting angular deviations during printing of printed images in a multicolor sheet-fed rotary printing press, comprising:
It has at least three impression cylinders and a sheet transport drum arranged between the impression cylinders, one end of which can be pivoted by means of an inclination adjustment device, and a plate cylinder in the printing section. In the type having a register adjustment device for circumferential register adjustment and lateral register adjustment, the diagonal register adjustment device is configured as a mechanical overlap type transmission device, and the The input part of the device includes a first tilt adjustment member (24) for pivoting the sheet transport drum (4).
), and the first
A second inclination adjustment element (25) for further pivoting of the sheet transport drum (4) is arranged on the inclination adjustment element (24) of the second inclination adjustment element (25). for the correction of obliquely located printed images, characterized in that a drive (28) is provided which produces a drive movement for the first tilt adjustment member (24) of the subsequent printing unit; equipment.