JPS63216744A - Method for controlling supply quantity of ink in printing press - Google Patents

Abstract

PURPOSE:To allow an open amount of ink fountain key to be set large to facilitate a control, by a method wherein, a maximum area is obtained from picture pattern areas per zone, a feed amount of ink is determined, a conversion table is selected with respect to a picture pattern area and an open amount of ink fountain key, and a supply quantity of ink is controlled by the feed amount of ink and the open amount of key. CONSTITUTION:A video signal from a camera 1 photographing a pressplate surface is converted to a digital signal by an analog-digital converter 3 containing a sample and hold circuit to be a measured value after being subjected to the correction of the value of wave height in a waveform correcting part 2, thereafter being stored in a RAM 4. The information of the RAM 4 is read by a CPU 5, and the CPU 5 executes a predetermined operation to obtain a maximum area from picture pattern areas per zone obtained by dividing a pressplate surface. According to the maximum area, a supply quantity of ink per zone is determined and sent through an interface 6 to a magnetic card mechanism 7, a printer 8, and a cathode ray tube 9. Then, the rotation speed of an ink supply roller is determined according to the largest area in the picture pattern areas per zone, and an open amount of ink fountain key is determined by a conversion table corresponding thereto. In this manner, the open amount of key can be set large independently of the variation of the picture pattern area.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for controlling the ink supply amount of a printing press.

[Conventional technology]

In a printing press, the printing plate surface is divided into multiple zones, the image area of each zone is measured photoelectrically using a measuring device, and the key opening amount corresponding to each zone of the ink fountain is determined according to the image area of each zone. Then, by setting the facing gap between the key provided in each zone facing the ink supply roller and the ink supply roller, and keeping the rotational speed of the ink supply roller constant, the printing plate is generally It is designed to control the amount of ink supplied to the area, and for this purpose, the "Picture Area Measuring Device" (I
No. 201008) etc. are used.

[Problem that the invention seeks to solve]

However, in the past, the rotational speed of the ink supply roller was set at the maximum speed of 50 inches, which remained unchanged, and only the ink fountain key device was varied. When the supply amount is small, the key opening amount decreases, and further adjusting the key opening amount based on this requires fine adjustment, which makes control difficult.
Due to the reduction in key spacing, the thickness of the ink that adheres to the roller is also reduced, and the ink supply roller group has a multi-stage configuration.
The film thickness tends to be large on the printing plate side and small on the ink fountain, which causes reverse trapping in which the ink on the printing plate side transfers back to the ink fountain, and the ink sac in the ink sac. This results in problems such as ink staining and gushing.

[Failure to resolve issues]

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

That is, in a printing press ink supply amount control method that measures the pattern area of each zone divided into a plurality of zones on the printing plate surface and controls the ink supply amount for each zone according to the pattern area, the pattern area for each zone is measured. Find the maximum area from among the areas, determine the ink feed amount by the ink supply roller according to this maximum area, select a conversion table between the image area and the ink fountain key device according to the maximum area, and use this conversion table. The key opening amount corresponding to the picture area for each zone is determined individually, and the ink supply amount is controlled depending on the ink feed amount and the key opening.

[Effect]

Therefore, the rotational speed of the ink supply roller is determined according to the maximum area of the pattern area for each zone, and the ink fountain key device is determined based on the corresponding conversion table.
Regardless of the increase or decrease in the picture area, the key opening amount is determined to be large.

〔Example〕

Hereinafter, the present invention will be explained in detail with reference to figures showing examples.

Figure 2 is a block diagram showing the electrical circuit of the pattern area measuring device.
The video signal from the WR undergoes wave height correction in a waveform correction unit (WR) 2, and then passes through an analog-to-digital converter (ADO) including a sampling and holding circuit.
) 3 into a digital signal, which becomes a measured value, and is stored in a variable memory (hereinafter referred to as RAM) 4.

Further, the contents of the RAM 4 are read out by a processor (hereinafter referred to as CPU) 5 such as a microprocessor connected to the data bus DB and address bus AB, and the CPU 5 executes a predetermined operation based on this. , calculate the image area of each zone by dividing the printing plate surface in the vertical direction, determine the corresponding ink supply amount for each zone, and then send it to the magnetic card machine # through the interface (hereinafter referred to as I/F) 6. II (hereinafter referred to as MC) 7, a printer (hereinafter referred to as PT) 8, and a cathode ray tube (hereinafter referred to as CRT) 9.

CAMl is a control signal generator (hereinafter referred to as CG) 1
ADO3 operates based on a synchronization signal from 0, and ADO3 performs sampling hold and conversion operations based on similar sampling pulses, and RAM4 has
A similar addressing signal (AD) is applied, thereby sequentially storing the output of ADO3.

The CPU 5 executes predetermined calculations and control operations according to instructions stored in a fixed memory (hereinafter referred to as ROMI 1), but a switch group (hereinafter referred to as S
W) 12 and a keyboard (hereinafter referred to as KB) 13, the lamp group (hereinafter referred to as PL) 14 blinks through the I/F 6 to display the operating status.

In addition, a start signal is given from the CPU 5 to the CG 10, and when CAM1 finishes the imaging operation for one printing plate, an end signal is given from the CG 10 to the CPU 5, and the CPU 5 starts calculation in response to this. It becomes.

Therefore, in the end, the ink supply amount depends on the rotation speed of the ink supply roller in the printing machine,
And, it is required as an ink fountain key device for each zone, and is recorded on a magnetic card by MC7.
Printout by PT8 and display by CRT8 are performed.

In addition, the imaging situation of the printing plate surface by CAMI, details of each part such as wR2, details of calculation processing by CPU5, etc.
This is as disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 58-201008.

However, when determining the ink feed amount and ink fountain key device, the CPU 5 in FIG. It is to be recorded.

That is, the picture area for each zone once stored in the RAM 4 is read out (101), and the maximum picture area is determined (Smax) (102). As the area ratio to be
kuSmax≦40(%)? J 112, 1-40<
5r111. ! ≦60(S)? J113, [60<Sm
! LX≦80(96)? J114 is sequentially determined, and depending on these Y (YES), the ink feed amount F and conversion table T are each r F = 10%.
・T=a J 121 , r F=20% ・T=
b J 122, r F=30chi・T=cJ123, "
While setting F=40chi・r=aj124, if all of steps 111 to 114 are N (No),
Define as F=50%・T=a 4125.

In the CPU 5, the counter for counting the zone number configured in the CPU 5 is set as 1=1j131, and the conversion table stored in the ROM 11 is set using the selected conversion table ``Find Kl corresponding to Si using T'' 132. After finding the ink fountain key device Ki corresponding to zone i based on
is checked, and while this is N, a counter is registered according to ``i=i+IJ142'', and steps 132 and subsequent steps are repeated.

In the case of multicolor printing, the process shown in FIG. 1 is performed for each printing plate of each color, and the ink feed amount F1 for each color is recorded in the magnetic card, and K to Kn is recorded in the key snack for each zone. By inserting this into the ink supply amount control device connected to the printing machine, the rotation speed of the ink supply roller is determined for each color unit, and the opening amount for each zone is determined, and this is used as the standard. The amount of ink supplied is automatically controlled.

Fig. 3 shows the custom conversion of the conversion table T, in which multiple curves of a""e are determined according to the relationship between the ink feed amount, key snacking, and ink consumption on the printing plate surface, and each of Q1 is non-linear. Moreover, the number of key snacks K is increased.

Therefore, data indicating the key opening rate in % is stored in each address of the ROM 11 corresponding to the picture area "4S%," and after storing these data for each curve a = a, steps 121 to
125, and according to step 132,
9Si and the corresponding address, ROM11
By reading from , Ki can be determined.

Note that the ink feed amount F may be calculated by the following equation and may be continuously changed.

F=-i Sm, Lx-f, f: ink feed amount before correction Further, the conversion characteristics shown in FIG. 3 can be arbitrarily selected depending on the situation.

Therefore, even if the picture area is small, the opening amount is larger than that of the conventional art, and the setting and control based on this becomes easy.

Further, as the key snacking increases, the film thickness of the ink that adheres to the ink supply roller increases, and the above-mentioned reverse trapping does not occur.

Further, since the maximum area of 5nlI0 is used as a reference, if the picture area of each zone is equal to y, each child is set faithfully to these areas.

The process shown in FIG. 1 may be performed not only in the pattern area measuring device, but also in an ink supply amount control device into which a magnetic card is inserted, and steps 111 to 1
14 and the corresponding settings of the ink feed amount F can be modified in various ways, such as by determining each numerical value according to the conditions.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, even if the picture area of the printing plate is small, the setting of the in-call key device is generally large, and the control thereof is easy, and the ink supply Since the thickness of the ink film that adheres to the roller is also large, reverse trapping does not occur, and each amount is determined based on the maximum area of the pattern area of each zone, so overall high fidelity settings are achieved. This provides a significant effect in controlling the amount of ink supplied to various printing presses.

[Brief explanation of the drawing]

The figures show an embodiment of the present invention, in which Fig. 1 is a flowchart of correction processing, Fig. #g2 is a block diagram showing the electric circuit of the picture area measuring device, and Fig. 3 is a diagram showing the conversion percentage of the 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)

[Claims] In a method for controlling an ink supply amount of a printing press, the ink supply amount control method for a printing press measures the picture area of each zone divided into a plurality of zones on a printing plate surface, and controls the ink supply amount for each zone according to the picture area. Find the maximum area among the picture areas of
The amount of ink fed by the ink supply roller is determined according to the maximum area, and a conversion table between the image area and the ink fountain key opening amount is selected according to the maximum area, and the conversion table for each zone is determined using the conversion table. A method for controlling an ink supply amount of a printing press, characterized in that the key opening amount corresponding to the picture area is determined individually, and the ink supply amount is controlled based on the ink feed amount and the key opening amount.