JP2971601B2 - How to detect incorrect mounting of printing plate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing method in which a printing plate is mounted on a plate cylinder such as offset printing or letterpress printing to perform a printing process, and more particularly to a printing method for detecting the suitability of a printing plate mounted on a plate cylinder. The present invention relates to a method for detecting an incorrectly mounted plate.

[0002]

2. Description of the Related Art In a printing apparatus, such as offset printing or letterpress printing, in which a printing plate is mounted on a plate cylinder to execute a printing process,
There is no device that detects the suitability of a printing plate mounted on a plate cylinder. For this reason, in the printing method using the conventional printing apparatus, the operator visually checks the printed paper surface during execution of the printing process, and determines whether the printing plate mounted on the plate cylinder is appropriate based on the print content. I was trying to judge.

[0003]

However, in the above-mentioned conventional printing method, an error in mounting the printing plate on the plate cylinder is found after the start of the printing process. The printing device inside must be temporarily stopped, and the printing process must be restarted after the proper printing plate is mounted again on the plate cylinder, resulting in time loss in the printing process,
There has been a problem that the operation is lengthened. In addition, since a mounting error is found after the printing process, even if it can be found, a large amount of waste paper occurs, causing a problem that increases the printing cost. There is a problem of getting rid of. For example, in a printing process such as a newspaper printing process in which several to several tens of systems are installed per factory, and hundreds of printing plates are attached to a single system, especially printing is performed. Misplacement of the plate is likely to occur, and the above-mentioned delay in the operation time and the occurrence of waste paper become a serious problem, and the possibility of overlooking the mistake increases.

SUMMARY OF THE INVENTION It is an object of the present invention to read a part of an image formed on a printing plate at a predetermined time after the printing plate is mounted on a plate cylinder and before printing is started, and based on the contents, read the mounted printing plate. It is an object of the present invention to provide a printing plate erroneous mounting detection method capable of preventing the delay of work time due to erroneous mounting of a printing plate, the occurrence of wasted paper, and the conveyance of erroneous printed matter by judging the suitability of printing plates. .

[0005]

According to a first aspect of the present invention, there is provided a method for detecting an incorrect mounting of a printing plate, comprising the steps of: detecting a printing surface of the printing plate at a predetermined time before starting printing after the printing plate is mounted on the plate cylinder; The extraneous characters including the data updated for each printing plate written in the margin are read, and the read extraneous characters are compared with the setting data to determine whether the attached printing plate is appropriate. to update the configuration data when it is determined that the printing plate is suitable, it prohibits the start of printing when the mounted printing plate is found not suitable, these readings, the determination, updating and
The prohibition is performed automatically .

According to a second aspect of the present invention, the predetermined time is a time when the plate cylinder is rotated at a low speed before printing.

[0007]

According to the method for detecting erroneous mounting of a printing plate described in claim 1, margin characters are read from the printing surface of the printing plate mounted on the plate cylinder at a predetermined time before the start of printing, and the margin characters are read into the setting data.
Then, a determination is made as to whether the printing plate mounted on the plate cylinder is appropriate. And when the printing plate mounted on the plate cylinder is suitable
To update the setting data. On the other hand, when it is determined that the printing plate mounted on the plate cylinder is not suitable, printing is prohibited. The margin characters are constituted by data unique to the image formed on the printing surface of the plate, such as date and number of plates, in addition to data such as the number of pages updated for each plate . The contents of the image formed on the printing plate can be known from the contents of the margin characters. Therefore, by comparing the margin characters read from the plate mounted on the plate cylinder with the margin characters of the image content to be printed next, it is determined whether the plate mounted on the plate cylinder is an appropriate plate. Can be determined. Further, when a proper printing plate is not mounted on the plate cylinder, the start of printing is prohibited, so that no waste paper occurs.

[0010] According to the printing plate erroneous mounting detection method, margin characters are read from the printing plate mounted on the plate cylinder while the plate cylinder is rotating at a low speed before printing. Therefore, the margin characters are read at a low moving speed of the printing surface of the printing plate, and the margin characters can be accurately read.

[0009]

FIG. 1 is a diagram showing a schematic configuration of a main part of a printing apparatus to which a printing plate erroneous mounting detection method according to an embodiment of the present invention is applied. The plate cylinder 1 is supported by a printing device about a rotation axis. A part of the peripheral surface of the plate cylinder 1 is formed with a notch in the longitudinal direction, and this part is used as a plate mounting portion 3. 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. 2, the plate cylinder 1 is pulled while pulling the other end of the printing plate 5 forward. Then, the printing plate 5 is wound around the peripheral surface of the plate cylinder 1. After this,
The other end of the printing plate 5 is fixed to the other end face 4b.

As shown in FIG. 1, a reading sensor 6 is provided so as to face the peripheral surface of the plate cylinder 1. The reading sensor 6 reads out the margin characters 7 of the image formed on the printing plate 5. The margin character 7 is written, for example, on the margin of a newspaper, and is constituted by data such as the date and the number of pages to be printed, and can specify the image content of the printing plate.

By providing a shutter on the reading sensor 6 and opening the shutter at the timing of reading the margin characters 7, the reading sensor 6 is prevented from being stained with ink or the like, and the margin characters 7 are always accurately read. You may be able to do it.

FIG. 3 is a block diagram of a main part of the control unit of the printing apparatus. The reading sensor 6, the motor driver 18, the key controller 19, and the display driver 20 are provided to the CPU 11 via the interface circuits 14 to 17.
Is connected. The motor driver 18 is the CPU 11
The motor 21 is driven based on the drive data output from. The motor 21 is connected to the plate cylinder 1 via a driving mechanism (not shown).
To rotate.

The key controller 19 is connected to a key panel 22 provided on an operation unit of the apparatus. The key panel 22 includes, for example, a print switch 24 for instructing the start of a printing process, and the plate cylinder 1 when the plate 5 is mounted on the plate cylinder 1.
Fine movement switch 2 which is operated when rotating the motor little by little
5 and the like are provided. The key controller 19 inputs data to the CPU 11 via the interface 16 in accordance with a switch operated on the key panel 22.

A display 23 is connected to the display driver 20. The display 23 is provided on the operation unit of the printing apparatus together with the key panel 22, and displays a message or the like for an operator. The display driver 20 is a CPU
The display 23 is driven based on the display data output from the display 11.

The CPU 11 totally controls the input / output devices according to a program written in the ROM 12 in advance.
Data input and output during this time is stored in a predetermined memory area of the RAM 13. For example, the memory area M
A1 stores setting data to be compared with the margin characters 7 written on the printing plate 5. This setting data is data that is updated each time a printing plate is exchanged, with a value previously input by a key operation on the key panel 22 as an initial value.

FIG. 4 is a flowchart showing a processing procedure of the control unit. The CPU 11 reads a switch operation on the key panel 22 (n1) and performs a process according to the operated switch. When the print switch 24 is operated, the motor 21 is driven (n2, n3), and when the reading sensor 6 faces the margin character 7 of the printing plate, the margin character is read using the reading sensor 6 (n4, n5). . Motor 21
Is detected by a sensor (not shown), and the reading timing at n5 is determined according to the detection result of this sensor.

Next, the setting data stored in the memory area MA1 of the RAM 13 is read (n6), and the margin character data and the setting data are compared. If the two data match in this comparison, the contents of the setting data are updated and stored in the memory area MA1 of the RAM 13 (n7, n
8) The paper is fed and a predetermined amount of printing is executed (n)
9). On the other hand, if the margin characters do not match the setting data, the motor 21 is stopped (n7 → n10), and the display 23
Will indicate that the printing plate has been incorrectly installed.

By the above processing, the margin characters are read out of the image formed on the printing plate 5 mounted on the plate cylinder 1, and
The data is compared with the data stored in the control unit. The printing process is executed only when both match in this comparison,
If they do not match, the printing process is not started.

Further, by the processing of n3 to n5, the motor 2
When the printing drum 1 reaches the reading position for the first time after the drive of the first drive, the margin characters are read. When a printing plate is mounted, the plate cylinder rotates at a low speed due to manual rotation, and thereafter gradually increases the rotation speed. Therefore, when the plate cylinder 1 reaches the reading position for the first time after the drive of the motor 21 is started, the plate cylinder 1 is still rotating at a sufficiently low speed, so that the reading sensor 6 can easily read the margin characters.

[0020]

According to the method for detecting erroneous mounting of a printing plate according to the first aspect, the printing process is started by using a part of an image formed on the printing plate to determine whether the printing plate mounted on the plate cylinder is appropriate. It can be automatically determined beforehand, and the print process that has been started once is not invalidated, and it is possible to prevent the printing process from being prolonged, generating a large amount of waste paper, and transporting erroneously printed materials. it can. In addition, there is no need for the operator to check the paper surface after the start of the printing process, and there is an advantage that labor can be saved for the operator. In addition, the setting data used to judge
Many settings for each printing plate
There is no need to input data in advance,
Force work can be done easily.

According to the printing plate erroneous mounting detection method, margin characters written on the printing plate can be accurately read, and erroneous mounting of the printing plate can be reliably detected.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a configuration of a main part of a printing apparatus to which a printing plate erroneous mounting detection method 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 mounted on a plate cylinder in the printing apparatus.

FIG. 3 is a block diagram of a control unit of the printing apparatus.

FIG. 4 is a flowchart illustrating a processing procedure of a control unit of the printing apparatus.

[Explanation of symbols]

 1-plate cylinder 5-printing plate 6-reading sensor 7-margin characters

──────────────────────────────────────────────────続 き Continued on front page (51) Int.Cl. ⁶ Identification code FI B41F 33/14 G

Claims (1)

(57) [Claims] At a predetermined time before printing is started after the printing plate is mounted on the plate cylinder, margin characters including data updated for each printing plate written outside the printing surface of the printing plate at a predetermined time are read and read. A comparison is made between the margin characters and the setting data to determine the suitability of the attached printing plate, and when it is determined that the attached printing plate is appropriate, the setting data is updated, and the attached printing plate is updated. prohibits the start of printing when is determined not to be suitable, this
A method for detecting erroneous mounting of a printing plate , wherein reading, determination, updating and prohibition thereof are automatically performed .