JPH04221642A - Control device of multi-color printer - Google Patents

Abstract

PURPOSE:To obtain a printed matter of high quality without the help of a skilled operator and maintain a printing state in an optimal state always on real time precisely, even if a rotary press is used by devising computerized printing process. CONSTITUTION:Control devices (fuzzy computers) 11, 12 correct a setting signal to a rotary press based on the difference between the integrated value of each color density for each zone which constitutes a picture surface of a printed matter in a running state and a reference value corresponding to the former through a fuzzy logic calculation.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a multicolor printing press, and more particularly to a control device for a multicolor printing press that can accurately maintain the printing conditions of a rotary press at an optimal state at all times and in real time.

0002

[Prior Art] Conventionally, in multicolor printing machines, it has been difficult to quantitatively evaluate the quality of printed matter, and operators have been able to determine the amount of blade opening, ink feed amount, etc. by visual judgment.
Setting values such as water feed amount and printing pressure were adjusted to optimize printing conditions. For this reason, it has been impossible to obtain high-quality printed matter unless a veteran operator is employed.

In recent years, inspection marks are printed in strips outside the image area of printed matter, density data for each color is read from the inspection marks using a density measuring device, and settings are made based on the read density data. People are beginning to adjust values, that is, adjust setting signals, and adjust printing conditions to optimal conditions.

0004

[Problems to be Solved by the Invention] However, in recent years, when applying this type of control method to a rotary press, the printed matter is folded to a certain size before being printed. The printed matter had to be unfolded and set in the density measuring device, which was not easy and was extremely time-consuming. For these reasons, the above-described control method has been applied only to sheet-fed machines. However, even when applied to a sheet-fed press, there is a time lag between the timing when a print sample is taken and the adjustment timing of the setting signal, which may result in over- or under-adjustment of the setting signal. was there.

[0005] As an example of application to a rotary press, the following method is partially adopted. In other words, a densitometer is installed on the rotary press so as to be movable in the direction perpendicular to the running direction of the printed matter (paper width direction), and the density data is measured one inspection mark at a time in synchronization with the rotation of the rotary press. A method of reading is adopted. However, in such a method,
Since the density data of one inspection mark is instantaneously read from a printed matter traveling at high speed, there are problems with accuracy and it is hardly ever put into practical use.

[0006]

[Means for Solving the Problems] The present invention has been proposed to solve the above problems, and it is an object of the present invention to divide each color density into each zone of a running printed matter divided approximately parallel to the flow direction. a density detection means capable of detecting the integrated value of , the integrated value of each color density for each zone constituting one screen of printed matter detected by this density detection means, and the corresponding reference value of each color density for each zone; The control means corrects the setting signal to the multicolor printing machine by correcting the deviation from the multicolor printing press and performing fuzzy logic operations.

[0007]

[Operation] Therefore, according to the present invention, it is possible to accurately maintain the printing condition in an optimal state in real time, even when various factors are intricately and subtly intertwined with each other, by performing fuzzy logic operations in the control means. becomes. Further, according to the present invention, since the integrated value of each color density is detected for each zone of the printed matter while it is running, there is no need to provide an inspection mark, and accurate density data can be obtained. In addition, concentration data can be read with high accuracy even when driving at high speed.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A control device for a multicolor printing press according to the present invention will be explained in detail below. FIG. 1 is a block diagram showing an embodiment of a control device for this multicolor printing press, which is applied to a rotary offset press. In the figure, 101 is a printed matter printed by a rotary press, 1 and 2 are densitometers placed opposite to each other on the front and back sides of this printed matter 101, and 3 is a direction perpendicular to the running direction of the printed matter 101, that is, the paper width. a moving device capable of moving the densitometers 1 and 2 in the direction; 4 a controller that controls the movement positions of the densitometers 1 and 2 via the moving device 3; 5 and 6 input a start position signal and an end position signal of the picture; In other words, the start position and end position of one screen in the traveling printed matter 101 are input, and the density data detected by densitometers 1 and 2 from the start position to the end position is separated into colors using a filter, and the density of each color is calculated. An integrating circuit that calculates and outputs an integrated value; 7 and 8 are current density registers that store integrated values of each color density for each zone (described later) output from integrating circuits 5 and 6; 9 and 10 are registers 7 and 8; A reference density register 11 stores the reference value of each color density for each zone correspondingly, and reference density register 11 is the integrated value of each color density for each zone stored in the current density register 7 and a reference density register 9.
The deviation from the reference value of each color density for each zone stored in is calculated, and the image area, paper quality, ink characteristics, temperature,
Initial conditions such as humidity and the above deviations are read through the membership function, and fuzzy logical operations are performed to determine each setting signal (blade opening amount, ink feed amount, water feed amount, etc.) for each color to the rotary press. The correction control device 12 calculates the deviation between the integrated value of each color density for each zone currently stored in the density register 8 and the reference value of each color density for each zone stored in the reference density register 10; Initial conditions such as image area, paper quality, ink characteristics, temperature, humidity, etc. and the above deviations of each color printing plate are read through the membership function, fuzzy logical operations are performed, and each setting signal ( This is a control device that adjusts the blade opening amount, ink feed amount, water feed amount, etc.).

[0009] The rotary press has a divided ink supply device for each printing unit of each color, which can independently vary the ink supply amount for each region divided parallel to the flow direction of the printed material 101. . The densitometer 1 has a function of measuring the density of the printed matter 101 for each color. The reference density registers 9 and 10 store in advance the reference value of each color density for each zone constituting one screen on a reference sheet such as a proof sheet or an OK sheet.

Next, the operation of the control device for this multicolor printing press will be explained. First, various conditions such as the image area of each color printing plate, paper quality, ink characteristics, temperature, and humidity are given to the control devices 11 and 12 as initial conditions. Thereby, the control devices 11 and 12 read the above conditions via the membership function. Then, a fuzzy logical operation is performed to generate each setting signal for each color to the rotary press, and this signal is output as each initial setting signal. With each of these initial setting signals, a printing condition of a considerable level, although not the best, can be obtained.

Next, from this printing state, the moving positions of the densitometers 1 and 2 are controlled by the controller 4 via the moving device 3.
control, and starts measuring the density of the printed matter 101 while it is running. In this case, densitometers 1 and 2 are
Each time one screen of No. 01 travels, its movement position is controlled so that it is sequentially positioned at the center of each zone on the printed matter 101 corresponding to each area divided by the divided ink supply device. As a result, when the density measurement in all zones is completed, the integrated value (current value) of each color density for each zone making up one screen of the printed matter 101 is stored in the current density registers 7 and 8. This stored data is sent to control devices 11 and 12 as control signals. Thereafter, in the same manner, the integrated value of each color density for each zone constituting one screen is stored in the current density registers 7 and 8 one after another, and control signals are sent to the control devices 11 and 12 each time. Become. At this time, the density measurement by the densitometers 1 and 2 is performed on the printed matter 101 while running at high speed, but since the integrated value of each color density of one zone is detected while one screen is running, Density data can be read with high accuracy even in the middle of the day.

On the other hand, the reference density registers 9 and 10 store reference values for each color density for each zone constituting one screen on the reference sheet, and this stored data is used as a reference signal to be sent to the control devices 11 and 12. is being sent to. In this embodiment, as shown in FIG. 2, a reference sheet 102 is pasted on an endless belt 13, and while the belt 13 is rotating, densitometers 1' and 2' are attached to the reference sheet 102.
A method is adopted in which the reference sheet 102 is sequentially moved to the center position of each zone of 2 to obtain the reference value of each color density for each zone constituting one screen on the reference sheet 102.

The control device 11 receives the control signal from the current density register 7 and the reference signal from the reference density register 9, and calculates the deviation between the integrated value of each color density for each zone and the reference value. Read the deviation via the membership function. Then, it performs fuzzy logical operations and corrects each setting signal for each color to the rotary press in real time to the optimum value, that is, so that the deviation between the integrated value of each color density for each zone and the reference value is zero. . The control device 12 is also similar to the control device 11, and receives the control signal from the current density register 8 and the reference signal from the reference density register 10, and calculates the integrated value of each color density for each zone and the reference value. The deviation is taken, fuzzy logic operations are performed, and each setting signal for each color to the rotary press is corrected to the optimum value in real time.

That is, according to the control device for a multicolor printing press according to this embodiment, the control device 1
Fuzzy logic operations are performed in steps 1 and 12, so that the printing condition of the rotary press is always maintained in the optimum condition in real time. In particular, according to this embodiment, it is possible to accurately maintain the printing condition in an optimum state even when various factors are complicated and subtly intertwined with each other in the printing condition. That is,
There are an extremely large number of factors that determine the printing condition, and since the ink supply device passes through many rolls from the ink supply device to the printed material 101, these factors are intricately and subtly intertwined to determine one printing condition, and the correlation between these factors Unless the relationship is accurately understood and the setting signals for each color to be sent to the rotary press are determined, it is not possible to always obtain good printed matter 101. In other words, the integrated values of the color densities for each zone that make up one screen of the printed matter 101, which has a complex mixture of multicolor halftone dots, are related to each other, and it is not easy to control these to the reference value. However, it is not possible to qualitatively determine how the set values (outputs) of the blade opening amount, ink feed amount, water feed amount, etc. for each color to the rotary press change in response to the inputs given to the control devices 11 and 12. , it's not difficult. Therefore, in this embodiment, as many fuzzy rules as possible regarding these inputs and outputs are created and logical operations are performed. At first, it was difficult to obtain accurate output, but by gradually modifying the membership function, we were able to achieve almost ideal control. In this way, in this example,
Since the control devices 11 and 12 adopt a method of performing fuzzy logic operations, that is, use fuzzy computers, it is possible to precisely maintain the printing state in an optimum state.

Furthermore, according to this embodiment, since the integrated value of each color density is detected for each zone constituting one screen of the printed matter 101 while it is running, it is not necessary to provide inspection marks as in the conventional method. Accurate concentration data can be obtained without the need for That is, the correspondence between the density of the inspection mark and the density of halftone dots in the screen is not necessarily accurate, and accuracy can be ensured by obtaining density data directly from the screen. In addition, in this example, a rotary press was explained as an example, but
Application to sheet-fed machines is also possible.

[0016]

[Effects of the Invention] As is clear from the above explanation, according to the present invention, the fuzzy logic operation in the control means
It is possible to accurately maintain the printing condition in real time at the optimum condition even when the printing condition changes in a complex and delicate manner due to various factors, and it is possible to obtain high-quality printed matter without hiring experienced operators. becomes. Further, according to the present invention, since the integrated value of each color density is detected for each zone constituting one screen of a printed matter while it is running, there is no need to provide an inspection mark, and accurate density data can be obtained. Furthermore, density data can be read with high accuracy even when running at high speed, and printing conditions can be maintained in an optimal state in real time without any problems even with a rotary press.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of a control device for a multicolor printing press according to the present invention.

FIG. 2 is a diagram illustrating a method of storing a reference value in a reference density register.

[Explanation of symbols]

101 Printed matter 1 Densitometer 2 Densitometer 3. Mobile device 4 Controller 5 Integration circuit 6 Integration circuit 7 Current concentration register 8 Current concentration register 9.Reference density register 10 Standard density register 11 Control device 12 Control device

Claims (1)

[Claims] 1. A density detecting means capable of detecting the integrated value of each color density for each zone of a running printed matter divided approximately parallel to the flow direction; Multi-color printing in which the deviation between the integrated value of each color density for each zone constituting one screen and the corresponding reference value of each color density for each zone is calculated, and a fuzzy logical operation is performed to print the printed matter. 1. A control device for a multicolor printing press, comprising: control means for modifying a setting signal to the machine.