DE102010045036A1 - Device for mounting printing plate on plate cylinder of printing press, has imaging sensor arranged on plate cylinder to detect elongation of pressure plate - Google Patents

Abstract

The device has cylinder channel (1) in which several clamping devices (2.1-2.4) are arranged at the forward and trailing edge. A pressure plate (3) is arranged on lateral surface of the rotatable plate cylinder (4). An adjusting device (6.1-6.4,7.1-7.4) stretches the pressure plate. An imaging sensor (12.1-12.4,13.1-13.4) arranged on plate cylinder detects an elongation of the pressure plate.

Description

The invention relates to a device for fastening a printing plate to a forme cylinder of a printing press according to the preamble of claim 1.

When printing with an offset printing machine, partial color images are successively transferred to a sheet or a web in succession by an elastic elevator. Due to the pressure and the influence of dampening solution, the paper expands to create register differences. In order to reduce the registration errors caused by paper stretch, it is known to stretch or compress printing plates. Because the respective sheet at the end expands more than at the beginning of sheet printing, the printing plates are deformed at the end of the plate. With split rear plate clamping rails, it is possible to deform a printing plate in the range of a few tenths of a millimeter, so that a concave arch elongation can be compensated.

The DE 4235393 A1 describes a register control arrangement in which register deviations are compensated with actuators. To compensate narrower or broader pressures act actuators on split rails of the pressure plate. The rule arrangement processes signals from register mark sensors. When generating actuating signals for the actuators, no measured values are processed that reflect a deformation of a printing plate.

In a printing press after the DE 10 2007 057 455 A1 a pressure plate is deformed by means of actuators in the axial and / or circumferential direction so that register deviations are compensated. The energy for the movement and the signals for controlling the actuators are transmitted by means of Drehübertragern on or from the forme cylinder. The actuators are equipped with a sensor that outputs signals to the position of a driven member, which is coupled via mechanical transmission elements with a plate clamping machine. The respective actuator with the output member and the mechanical transmission elements form a kinematic chain with clearance fits between the links. From the signals of the position sensor of the actuators deformation of the pressure plate can not be determined with sufficient accuracy.

In a device for tensioning and adjusting a printing plate on a plate cylinder after the DE 4223908 C2 sensors are arranged with which it can be checked whether a terminal block is in a starting position. The sensors are not designed to detect a plate strain.

The object of the invention is to develop a device for fastening a printing plate to a forme cylinder of a printing press, with which it is possible to improve the accuracy in measuring a plate strain or plate compression.

The object is achieved with a device having the features of claim 1. Advantageous embodiments emerge from the subclaims.

According to the invention, at least one sensor representing the expansion of the printing plate is arranged on a forme cylinder. If a terminal strip acting on the trailing edge is used to deform the printing plate, the sensor can be arranged fixed in the cylinder and directed onto a surface of the terminal strip. If it is assumed that the edge is held firmly in the terminal strip, then the deformation of the printing plate in the circumferential and / or lateral direction results directly from the position of the clamping strip on the forme cylinder. The deformation of the printing plate, d. H. the amount of stretch or compression may be output to an operator of the printing press on a display device. An arrangement for sensor signal processing can be arranged directly on the forme cylinder, wherein the arrangement can be in communication with a stationary control device of the printing press.

The invention will be explained below with reference to an exemplary embodiment, in which:

1 : a plate cylinder facing a cylinder channel, and

2 : a section through a plate cylinder.

The 1 and 2 show a rotatably mounted plate cylinder of a printing machine with a view of a cylinder channel 1 and in section through a terminal block 2 at the trailing edge of a printing plate 3 , The printing plate 3 lies on the lateral surface of the cylinder body 4 on and is at the leading edge with an across the width of the pressure plate 3 reaching terminal block 5 held. The clamping device on the leading edge is fixedly seated on the cylinder body 4 , For holding, clamping and deforming the printing plate 3 at the trailing edge are four clamping devices with four terminal strips 2.1 to 2.4 intended. By means of actuators 6.1 to 6.4 and 7.1 to 7.4 are the terminal strips 2.1 to 2.4 independently in the lateral direction 8th and in the circumferential direction 9 positionable. Different positioning paths of the terminal strips 2.1 to 2.4 cause an expansion and / or compression of the printing plate 3 at the trailing end in the elastic region. The actuators 6.1 to 6.4 and 7.1 to 7.4 each consist of a drive member and at least one output member, which with the respective terminal block 2.1 to 2.4 is coupled. How closer in 2 shown, z. B. an actuator 7 for adjusting a terminal strip 2 in the circumferential direction 9 from a piezo drive 10 and a lever drive 11 , The clamping device or the terminal strips 2.1 to 2.4 are in the circumferential direction 9 and in the lateral direction 8th guided in swivel joints and / or push joints.

The terminal strips 2.1 to 2.4 own in the lateral direction 8th and in the direction of rotation 9 Indicator surfaces, on the non-contact distance sensors 12.1 to 12.4 and 13.1 to 13.4 are directed. The with the cylinder-fixed sensors 12.1 to 12.4 and 13.1 to 13.4 detected distance changes correspond to the positioning paths of the terminal strips 2.1 to 2.4 in side direction 8th and in the direction of rotation 9 , Because the trailing edge of the printing plate 3 firmly under the terminal strips 2.1 to 2.4 sits, the positioning corresponds to the degree of stretching or compression of the pressure plate in the lateral direction 8th or in the circumferential direction 9 in the area of the respective terminal block 2.1 to 2.4 , The distance sensors 12.1 to 12.4 and 13.1 to 13.4 are over a bus line 14 with a signal processing circuit 15 connected in the channel 1 is arranged. The actuators 6.1 to 6.4 and 7.1 to 7.4 are with a control circuit 16 connected. About rotary joints 17 . 18 lead signal lines 19 and control lines 20 to a control unit 21 for the printing press. The control unit 21 contains a computer in which programs run, the signals of the distance sensors 12 . 13 process, the actuating signals for the actuators 6 . 7 generate and the amounts and directions of deformation of the printing plate 3 on a display unit 22 output.

The invention is not limited to the illustrated embodiment. It is alternatively possible to provide deformation sensors which are directly on the pressure plate 3 are directed. The signals of the sensors 12 . 13 can by radio to the controller 21 be transmitted. The sensors designed as distance sensors 12 . 13 may include optical, capacitive or inductive transducers.

LIST OF REFERENCE NUMBERS

1

cylinder gap

2

terminal block

3

printing plate

4

cylinder body

5

terminal block

6, 7

actuator

8th

lateral direction

9

circumferentially

10

piezo drive

11

lever drive

12, 13

distance sensor

14

bus line

15

Signal processing circuit

16

control circuit

17, 18

Rotary joint

19

signal line

20

control line

21

control unit

22

display unit

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 4235393 A1 [0003]
• DE 102007057455 A1 [0004]
• DE 4223908 C2 [0005]

Claims (8)

Device for fastening a printing plate to a forme cylinder of a printing machine, with at least one cylinder channel ( 1 ) arranged clamping devices ( 2 . 5 ) for the leading and trailing edge of the bearing on the bearing surface of the rotatable forme cylinder ( 4 ) resting pressure plate ( 3 ), and with at least one adjusting device ( 6 . 7 ) for stretching the printing plate ( 3 ), characterized in that on the forme cylinder ( 4 ) an elongation of the printing plate ( 3 ) reproducing sensor ( 12 . 13 ) is arranged. Device according to claim 1, characterized in that the sensor ( 12 . 13 ) for detecting the position of the trailing edge of the printing plate ( 3 ) attacking terminal block ( 2 ) in lateral direction ( 8th ) and / or in the circumferential direction ( 9 ) Is arranged fixed to the cylinder. Device according to claim 2, characterized in that on the terminal strip ( 2 ) at least one indicator surface is formed, to which the respective sensor ( 12 . 13 ). Device according to claim 1, characterized in that the sensor ( 12 . 13 ) with a stretch reproducing display device ( 22 ). Device according to claim 1, characterized in that the sensor ( 12 . 13 ) with one on the forme cylinder ( 4 ) arranged evaluation circuit ( 15 ) connected is. Device according to claim 5, characterized in that the evaluation circuit ( 15 ) with a control device ( 21 ) is connected to the printing press. Device according to claim 5, characterized in that the adjusting device comprises at least one actuator ( 6 . 7 ) which is connected to at least one terminal strip ( 2 ) for the trailing edge, and that the control device ( 21 ) with the actuator ( 6 . 7 ) connected is. Device according to claim 7, characterized in that the adjusting device is a lever mechanism ( 11 ) contains.

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