JPH04308755A - Method for detecting erroneous mounting of press-plate - Google Patents

Abstract

PURPOSE:To prevent that detecting data becomes impossible to read by contami nation when the erroneous mounting of a press-plate to a plate cylinder in a printing apparatus is automatically detected before the of printing processing. CONSTITUTION:Inherent plate data 7 is preliminarily displayed on the press-plate 5 mounted on a plate cylinder 1 as a code high in a degree of redundancy. This plate data 7 is read before the start of printing to be compared with the set data stored in a control part.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] This invention relates to a printing method such as offset printing or letterpress printing in which a printing plate is attached to a plate cylinder and printing processing is carried out, and in particular a printing method that detects the suitability of a printing plate attached to a plate cylinder. Concerning a method for detecting incorrect mounting of a plate.

0002

[Prior Art] In printing apparatuses such as offset printing and letterpress printing, in which a printing plate is attached to a plate cylinder and printing processing is carried out,
There was no device designed to detect the suitability of the printing plate mounted on the plate cylinder. For this reason, in printing methods using conventional printing devices, the operator visually inspects the printed paper surface during the printing process and determines whether the printing plate mounted on the plate cylinder is appropriate based on the printed content. I was trying to judge.

0003

[Problems to be Solved by the Invention] However, in the above-mentioned conventional printing method, errors in mounting the printing plate on the plate cylinder are discovered after the printing process has started, and if an operator discovers this, the operation cannot be carried out. It is necessary to temporarily stop the printing device inside the printer, reinstall the appropriate printing plate on the plate cylinder, and then restart the printing process, which causes time loss in the printing process.
There was a problem that led to longer work hours. In addition, since loading errors are discovered after the printing process, even if they were discovered, a large amount of wasted paper would be generated, leading to an increase in printing costs. The problem of putting it away arises. For example, in printing processes such as newspaper printing, where several to ten or more systems are installed per factory, and a single system is loaded with hundreds of printing plates, this is especially true. It is easy to erroneously mount the plate, causing major problems such as the delay in working time and the occurrence of paper waste, and the possibility of overlooking mistakes increases.

An object of the present invention is to read data written on the printing plate in advance at a predetermined time after the printing plate is mounted on the plate cylinder and before starting printing, and to determine whether or not the mounted printing plate is suitable based on this data. It is an object of the present invention to provide a method for detecting erroneous mounting of a printing plate, which can prevent delays in working time, occurrence of paper waste, and transportation of erroneous printed matter due to erroneous mounting of a printing plate.

[0005]

[Means for Solving the Problems] The method for detecting incorrect attachment of a printing plate according to claim 1 is characterized in that a code unique to the printing plate and having a high degree of redundancy is previously written at a predetermined position on the printing plate. The printing plate is characterized in that the code is read at a predetermined time after the printing plate is mounted on the plate cylinder, and the suitability of the mounted printing plate is determined based on this code.

[0006] In the method for detecting erroneous mounting of a printing plate, the highly redundant code is a multiplex of unique codes.

[0007] In the method for detecting erroneous mounting of a printing plate, the predetermined time is a time when the plate cylinder rotates at a low speed before printing.

[0008] In the method for detecting erroneous mounting of a printing plate, the predetermined position is a second folded portion of the printing plate.

[0009]

In the method for detecting erroneous attachment of a printing plate according to claim 1, the suitability of the printing plate is determined based on highly redundant codes written on the printing plate. Therefore, even if a part of the code is stained by ink droplets, the contents can be read accurately.

[0010] In the method for detecting incorrect attachment of a printing plate according to claim 2, a highly redundant code formed by multiplexing unique codes is read, and the suitability of the printing plate is determined based on this code. It will be done. Therefore, it becomes easy to construct codes with high redundancy.

In the method for detecting erroneous mounting of a printing plate, the code written on the printing plate is read while the plate cylinder on which the printing plate is mounted rotates at a low speed. Therefore, the code reading accuracy is further improved.

[0012] In the method for detecting incorrect mounting of a printing plate according to claim 4, the suitability of the printing plate is determined by reading the code written on the second fold of the printing plate. Therefore, the possibility of the code being stained is reduced, and the accuracy of code reading is improved.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram showing a schematic configuration of the main parts of a printing apparatus to which a method for detecting erroneous mounting of a printing plate according to an embodiment of the present invention is applied. The plate cylinder 1 is supported by a printing device around a rotation axis. A notch is formed in a part of the circumferential surface of this plate cylinder 1 in the longitudinal direction, and this part is used as a mounting part 3 for a printing plate. That is, after attaching one end of the printing plate 5 to one end surface 4a formed on the mounting portion 3 as shown in FIG. The printing plate 5 is wound around the circumferential surface of the printing cylinder 1 by rotating it. After this,
The other end of the printing plate 5 is fixed to the other end surface 4b.

As shown in FIG. 1, one end surface 4 of the plate cylinder 1
A reading sensor 6 is installed so as to face this end surface 4a when a is in a horizontal state. This reading sensor 6
reads the unique plate data 7 written on the printing plate 5. This plate data 7 is written on the second fold section 5b of the printing plate 5. This version data 7 is, for example, barcode data,
It consists of data such as the date and number of pages to be printed, and allows the image content of the printing plate to be specified.

FIG. 3 shows an example of the structure of data written on the printing plate. A total of 25 data are displayed.
Although the data is 6 bits, about 30 bits of the data specify the image content as described above, and the rest are redundant bits. This redundant bit determines whether the data read by the reading sensor has been contaminated by ink droplets or the like. A known method can be used to create this redundant bit.

FIG. 4 is a diagram showing how the main parts of the printing plate are attached in the printing apparatus. The printing plate 5 is on the back side 4c of the plate cylinder 1
The first folded portion 5a of the printing plate 5 is placed opposite to the first folded portion 5a of the printing plate 5, the back side of the second folded portion 5b is placed opposite to one end surface 4a of the plate cylinder 1, and the back surface of the image portion 5c of the printing plate 5 is placed on the circumferential surface of the plate cylinder 1. to face each other. As a result, when one end surface 4a of the plate cylinder 1 is located in a horizontal state, the plate data 7 written on the second folded portion 5b of the printing plate 5 faces the reading sensor 6.

Note that by providing a shutter on the reading sensor 6 and opening this shutter at the timing of reading the plate data 7, the reading sensor 6 is prevented from being soiled with ink, etc., and the plate data 7 can be read accurately at all times. It may be possible to do so.

Further, the unique plate data 7 written on the printing plate 5 can be written by multiplexing code data having the same content, as shown in FIG. 4(A), for example. By multiplexing and writing a predetermined number of 2-bit data in which dark areas are set to 1 and bright areas to 0, even if part of the plate data is stained by ink droplets, etc., the dark areas will be displayed. Since it does not change to a bright area, for example, data i,
In a case like j, it can be recognized that the data in the lower two rows are stained, and it is possible to judge whether or not the printing plate 5 is appropriate based on the content written in the top row.

FIG. 6 is a block diagram of the main parts of the control section of the printing apparatus. A reading sensor 6, a motor driver 18, a key controller 19, and a display driver 20 are connected to the CPU 11 via interface circuits 14 to 17.
is connected. The motor driver 18 is the CPU 11
The motor 21 is driven based on drive data output from the motor. This motor 21 is connected to the plate cylinder 1 via a drive mechanism (not shown).
Rotate.

A key panel 22 provided at the operation section of the device is connected to the key controller 19. This key panel 22 includes, for example, a printing switch 24 for instructing the start of printing processing, a printing switch 24 for instructing the start of printing processing, and a printing switch 24 for instructing the printing plate 5 to be mounted on the printing cylinder 1.
Fine movement switch 2 that is operated when rotating the
5 etc. are provided. The key controller 19 inputs data to the CPU 11 via the interface 16 in accordance with the switches operated on the key panel 22.

A display 23 is connected to the display driver 20 . This display 23 is provided in the operation section of the printing apparatus together with the key panel 22, and displays messages to the operator. The display driver 20 is a CPU
The display device 23 is driven based on the display data output from the display device 11.

The CPU 11 centrally controls the input/output devices described above according to a program written in the ROM 12 in advance. Data input and output during this period is stored in a predetermined memory area of the RAM 13. For example, memory area M
Setting data to be compared with plate data written on the printing plate 5 is stored in A1. This setting data is key panel 2
The initial value is the value inputted in advance by the key operation in step 2, and the data is updated every time the printing plate is replaced.

FIG. 7 is a flowchart showing the processing procedure of the control section. The CPU 11 reads switch operations on the key panel 22 (n1) and performs processing according to the operated switch. When the print switch 24 is operated, the motor 21 is driven (n2, n3), and after the motor 21 is driven, when one end surface 4a of the plate cylinder 1 reaches a reading position where it is in a horizontal state, the reading sensor 6 is used to drive the motor 21 (n2, n3). Read the version data (n4, n5).

The amount of rotation of the motor 21 is detected by a sensor not shown, and n is determined based on the detection result of this sensor.
The reading timing in step 5 is determined. The read data is also subjected to processing such as removing redundant bits.

Next, the setting data stored in the memory area MA1 of the RAM 13 is read out (n6), and the version data and the setting data are compared. If both data match in this comparison, update the settings data and perform RA.
Store in memory area MA1 of M13 (n7, n8),
The paper is fed and a predetermined amount of printing is executed (n9). On the other hand, if the printing plate data and setting data do not match, the motor 21 is stopped (n7→n10), and the display 23 indicates that the printing plate is incorrectly installed.

Through the above processing, the plate data written on the second fold 5b of the printing plate 5 mounted on the plate cylinder 1 is read and compared with the data stored in the control section. In this comparison, print processing is executed only if the two match, and if they do not match, print processing is not started.

[0027] Also, by processing n3 to n5, motor 2
The plate data is read when the plate cylinder 1 reaches the reading position for the first time after being driven. When the printing plate is attached, the plate cylinder rotates at a low speed because it is manually rotated, and after the plate is attached, the rotation speed is gradually increased until printing starts.

Therefore, when the plate cylinder 1 reaches the reading position for the first time after the motor 21 starts driving, it is still rotating at a sufficiently low speed, and the plate data can be easily read by the reading sensor 6. Also, version data 7
Since it is written on the second folded portion 5b of the printing plate 5, it will not be easily stained by ink or the like.

[0029]

[Effects of the Invention] According to the method for detecting incorrect mounting of a printing plate as described in claim 1, data written on the printing plate in advance is read at a predetermined time after the printing plate is mounted on the plate cylinder and before printing starts. By determining the suitability of the installed printing plates based on this data, it is possible to prevent delays in work time, occurrence of paper waste, and transportation of incorrect printed matter due to incorrect installation of printing plates. When automatically determining the suitability of a printing plate mounted on a plate cylinder before the printing process begins, it is possible to reduce the probability that plate data will become unreadable due to contamination due to ink splashes, etc., and to improve data reading accuracy. You can improve your performance.

According to the method for detecting erroneous mounting of a printing plate, highly redundant data to be written on the printing plate can be easily constructed.

According to the method for detecting erroneous mounting of a printing plate, data is read when the plate cylinder rotates at a low speed, so that highly redundant data can be read more accurately.

[0032] According to the method for detecting incorrect mounting of a printing plate as described in claim 4, since data is written on the second fold of the printing plate, data is prevented from being soiled by ink splashes, etc., and the data can be read accurately. be able to.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing the configuration of a main part of a printing apparatus to which a method for detecting incorrect mounting of a printing plate according to an embodiment of the present invention is applied.

FIG. 2 is a perspective view showing a state in which a printing plate is attached to a plate cylinder in the printing apparatus.

FIG. 3 is a diagram illustrating the configuration of an example of plate data written on a printing plate to which the incorrect mounting detection method according to the embodiment of the present invention is applied.

FIG. 4 is an enlarged view of main parts showing how a printing plate is attached to a plate cylinder in the printing apparatus.

FIG. 5 is a diagram showing the configuration of plate data written on a printing plate according to another embodiment of the present invention.

FIG. 6 is a block diagram of a control unit of the printing apparatus.

FIG. 7 is a flowchart showing a processing procedure of a control unit of the printing apparatus.

[Explanation of symbols]

1-Print cylinder 5-Printing plate 5b-Second folding part 6-Reading sensor 7-edition data

Claims (4)

[Claims] Claim 1: A code that is unique to the printing plate and has a high degree of redundancy is written in advance at a predetermined position on the printing plate, and the code is read at a predetermined time after the printing plate is mounted on the plate cylinder, and the code is read. 1. A method for detecting incorrect mounting of a printing plate, characterized in that the suitability of the mounted printing plate is determined based on the suitability of the mounted printing plate. 2. The method for detecting incorrect attachment of a printing plate according to claim 1, wherein the code having a high degree of redundancy is a multiplexed code. 3. The method for detecting incorrect mounting of a printing plate according to claim 1, wherein the predetermined time is a time when the plate cylinder rotates at a low speed before printing. 4. The method for detecting incorrect mounting of a printing plate according to claim 1, wherein the predetermined position is a second folded portion of the printing plate.