JP2571688B2 - Ink supply control method for printing press - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for controlling an ink supply amount of a printing press.

[Conventional technology]

In a printing press, the printing plate surface is divided into multiple zones,
The pattern area of each zone is measured photoelectrically by a measuring device, and the key opening amount corresponding to each zone of the ink fountain is determined according to the pattern area of each zone, whereby each zone is opposed to the ink supply roller. In addition to setting the gap between the key provided for each ink and the ink supply roller, the rotational speed of the ink supply roller is kept constant, and the amount of ink supplied to the printing plate is generally controlled. For the purpose, a "pattern area measuring device" (Japanese Patent Application Laid-Open No.
No. 1008).

[Problems to be solved by the invention]

However, conventionally, the rotation speed of the ink supply roller is set to, for example, 50% of the maximum speed, which is not changed, and only the opening amount of the ink fountain key is changed. When the supply amount is small, the key opening amount is reduced, and fine adjustment is required to further adjust the key opening amount based on this, so that control becomes difficult, and
As the key opening decreases, the film thickness of the ink adhering to the rollers also decreases.
Since the plate side has a tendency to have a large film thickness and the ink fountain side has a tendency to have a small film thickness, reverse trapping occurs in which the ink on the plate side is transferred to the ink fountain side. This leads to problems such as contamination of the ink.

[Means for solving the problem]

In order to solve the above-mentioned problem, the present invention is constituted by the following means.

That is, in the ink supply amount control method for a printing press, which measures the picture area of each of a plurality of divided zones on the printing plate surface and controls the ink supply quantity for each zone according to the picture area, The average area is determined by the pattern area of the image, the average area is determined, the amount of ink supplied by the ink supply roller determined by the rotation amount of the ink supply roller is determined according to the average area, and the pattern area is determined according to the average area. And a key opening amount corresponding to the picture area of each zone using the converting means. The ink supply amount and the key opening amount are calculated based on the ink feed amount and the key opening amount. The amount is controlled.

[Action]

Therefore, according to the present invention, the amount of ink supplied by the ink supply roller (the amount of rotation of the ink supply roller) is determined according to the average area obtained from the image area of each zone, and the pattern area and the ink fountain are determined according to the average area. A key opening amount conversion means (conversion table) is selected, and the key opening amount corresponding to the picture area for each zone is determined for each zone using this conversion means. It can be large.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to the drawings showing examples.

FIG. 2 is a block diagram showing an electric circuit of the picture area measuring device, and a camera (hereinafter, referred to as CAM) 1 for imaging a printing plate surface.
Is converted into a digital signal by an analog-to-digital converter (hereinafter, ADC) 3 including a sampling and holding circuit, after a peak value is corrected in a waveform correction unit (hereinafter, WR) 2, and the measured value and After that, it is stored in a variable memory (hereinafter, RAM) 4.

The contents of the RAM 4 are read by a processor (hereinafter referred to as a CPU) 5 such as a microprocessor connected by a data bus DB and an address bus AB. The image area of each zone where the printing plate is divided in the vertical direction is determined, and the ink supply amount for each zone is determined in accordance with the area. Then, the magnetic card mechanism (hereinafter, referred to as I / F) 6 is provided via an interface (hereinafter, I / F) 6. MC)
7, Printer (hereinafter, PT) 8 and CRT (hereinafter, PT)
CRT) 9.

However, the CAM 1 operates based on a synchronization signal from a control signal generator (hereinafter, CG) 10, the ADC 3 performs a sampling hold and conversion operation based on the same sampling pulse, and the RAM 4 Are supplied with the same address designation signal (AD), and the output of the ADC 3 is sequentially stored.

The CUP 5 performs a predetermined calculation and control operation in accordance with a command stored in a fixed memory (hereinafter, ROM 11), and a switch group (hereinafter, SW) 12 and a keyboard (hereinafter, KB) via the I / F 6 ) Operates according to the command from 13 and I /
A lamp group (hereinafter, PL) 14 is turned on and off via F6 to display an operation status.

In addition, while the start signal is provided from the CPU 5 to the CG 10, when the CAM 1 completes the imaging operation for one printing plate, an end signal is provided from the CG 10 to the CPU 5.
The CPU 5 starts the calculation.

Therefore, finally, the ink supply amount is determined by the rotation amount of the ink supply roller that changes according to the rotation speed of the ink supply roller in the printing press. The opening amount of the ink fountain key is obtained, the recording on the magnetic card is performed by the MC 7, the printout by the PT 8 and the display by the CRT 8 are performed.

Note that the imaging state of the printing plate surface by CAM1, details of each unit such as WR2, and details of arithmetic processing by CPU 5 are as disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 58-201008.

However, the CPU 5 shown in FIG. 2 performs a correction process shown in the flowchart of FIG. 1 when determining the ink feed amount and the ink fountain key opening amount, and records the obtained result on a magnetic card. It is something to do.

That is, the picture area for each zone once stored in the RAM 4 “S _{1 to} S _n · read” 101 is performed, and the average picture area “Determine S _a ” 102 based on these is performed, and then the solid area of the picture is obtained. As area ratio S _{a (P) with} “0 ≦ S _{a (P)}
≦ 20 (%)? 111 ”,“ 20 ≦ S _{a (P)} ≦ 40 (%)? ”112,
“40 ≦ S _{a (P)} ≦ 60 (%)?” 113 “60 ≦ S _{a (P)} ≦ 80 (%)
? "114", and these Y
(YES) Ink feed amount F and conversion table T
And “F = 10% · T = a” 121 and “F = 20% · T =
b ”122,“ F = 30% · T = c ”123,“ F = 40% · T =
On the other hand, if all of the steps 111 to 114 are N (NO), it is determined as “F = 50% · T = e” 125.

Then, the counter for the zone number counted configured into CPU5 and excisional by "i = 1" 131, "obtaining a K _i corresponding to S _{i (P)} with a T" conversion table selected by 132, in ROM11 after having determined the corresponding ink fountain key Hirakiryou K _i and zone i based on the conversion table stored into,
"I = n + 1?" 141 is checked, and while this is N, "i = n + 1?"
= I + 1 "142, the counter is incremented, and step 132 and subsequent steps are repeated.

In the case of multicolor printing, performs the processing of FIG. 1 for each plate for each color, ink feed rate F of each color into the magnetic card, and, the key Hirakiryou K ₁ ~K _n for each zone records By inserting this into an ink supply control device connected to the printing press, the rotation speed (rotation amount) of the ink supply roller is determined for each color unit, and the key opening amount for each zone is determined. Automatic control of the ink supply amount is performed based on this.

FIG. 3 shows the conversion characteristics of the conversion table T, in which a plurality of curves a to e are defined according to the relationship between the ink feed amount and the key opening amount and the pattern area ratio of the printing plate surface, each of which is non-linear. In addition, the key opening amount K is increased with an increase in the picture area ratio S _(P) .

Therefore, data indicating the key opening K is stored in each address of the ROM 11 corresponding to the pattern area ratio S _(P) , and these are stored for each of the curves a to e, and according to the selection of steps 121 to 125, Further, by specifying the address corresponding to Si _(P) in step 132 and reading out from the ROM 11,
_i can be found.

The ink feed amount F may be calculated by the following equation, and may be continuously changed.

F, Ink feed amount before correction Further, the conversion characteristics in FIG. 3 can be arbitrarily selected depending on the situation.

Therefore, even with a small picture area, the key opening amount becomes larger than before, and setting and control based on the key opening amount become easy.

In addition, as the key opening increases, the thickness of the ink adhering to the ink supply roller increases, and the above-described reverse trapping does not occur.

Furthermore, since the average area Sa is used as _a reference, even if there is a partial increase or decrease in the picture area of each zone, the influence of this is eliminated.

However, the processing of FIG. 1 may be performed not only by the picture area measuring device but also by the ink supply amount control device into which the magnetic card is inserted. The setting status of the ink feed amount F according to the condition may be such that each numerical value may be determined according to the conditions,
Various modifications are possible.

〔The invention's effect〕

As is apparent from the above description, according to the present invention, even when the pattern area of the printing plate is small, the setting of the ink fountain key opening amount is generally large, and the control thereof is facilitated, and the ink supply roller can be easily controlled. Since the ink film thickness to be attached also becomes large, reverse trapping does not occur, and since each amount is determined based on the average area according to the picture area of each zone, the influence of partial increase or decrease of the picture area is eliminated. In addition, a remarkable effect can be obtained in controlling the ink supply amount of various printing machines.

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention, FIG. 1 is a flowchart of a correction process, FIG. 2 is a block diagram showing an electric circuit of a picture area measuring device, and FIG. 3 is a diagram showing conversion characteristics of a conversion table. . 1 CAM (camera), 3 ADC (analog / digital converter), 4 RAM (variable memory), 5 CPU (processor), 7 MC (magnetic card mechanism), 11… ROM
(Fixed memory).

Claims (1)

(57) [Claims] An ink supply amount control method for a printing press, comprising: measuring a picture area of each of a plurality of divided zones on a printing plate surface; and controlling an ink supply quantity of each of the zones according to the picture area. The average area is determined from the picture area of each zone, the amount of ink supplied by the ink supply roller determined by the rotation amount of the ink supply roller is determined according to the average area, and the picture area and the ink fountain are determined according to the average area. A key opening amount conversion means is selected, and using this conversion means, a key opening amount corresponding to the picture area of each zone is obtained individually, and the ink supply amount is controlled by the ink feed amount and the key opening amount. A method for controlling an ink supply amount of a printing press, characterized by performing the following.