JPH08462B2 - Correction reference point setting method for automatic register adjustment - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method of setting a correction reference point when automatically adjusting a registration error between colors of a multicolor printing machine.

[Conventional technology]

In a multi-color printing machine such as a rotary printing machine, the register between each color fluctuates according to the printing material such as printing paper, blanket, ink, etc., and the change in printing conditions such as tension applied to the paper and ink tack. The method disclosed in Japanese Patent Application Laid-Open No. 58-14751 filed by the applicant of the present application is gradually prevailing for the purpose of automatically detecting the error and correcting the registration error between the respective colors.

[Problems to be Solved by the Invention] However, in the related art, the register mark printed for each color is detected, and the register error between the colors is obtained based on the detection output. , The reference color is fixed to the first color or the second color, or a specific color is selected by a person in charge from each color, and the print status of the register mark based on the fixedly set color is used as the reference. When looking at the register error amount in general, this fixedly set color is not the center of the error occurrence distribution situation, and it may be necessary to make corrections and register adjustment Since the control by driving the motor is used, the correction takes a long time, and every time the correction is performed more than necessary, a large amount of defective paper such as duplicate printing occurs, which causes an uneconomical problem.

[Means for solving problems]

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

That is, in the method for automatically performing register adjustment of the above, calculated in each individual misregister amount E ₂ to E _n between the other colors with reference to the specific color in each color, and, from the respective error amount in Positive direction maximum error amount E _max1 and negative direction maximum error amount E _max2
Then, the intermediate value between the maximum error amount E _max1 in the positive direction and the maximum error amount E _{max2 in the} negative direction, that is, (E _max1 + E _max2 ) / 2 is set as the corrected reference rotation E _F, and E _ir = E _i −E _F = 1 to n) determine the correction error amount E _1r to E _nr for each color, the correction error amount E _1r to E _nr
The correction target values S _{D1 to} S _Dn for each color are obtained based on the above, and the register adjustment of each color is performed almost simultaneously according to the correction target values S _{D1 to} S _Dn .

[Action]

Therefore, the middle of the error distribution range is set as the correction reference point according to the error occurrence distribution status of each color, and the correction target value for each color is determined based on this, and these correction target values are set. Since the registration adjustment is made, an average correction is made without making unnecessary corrections.

〔Example〕

Hereinafter, the details of the present invention will be described with reference to the drawings illustrating examples.

FIG. 2 is a block diagram of an electric circuit for obtaining a correction target value. The output of a photoelectric sensor (hereinafter, LES) 21 that detects a register mark printed for each color on paper is output by a waveform shaping circuit (hereinafter, WFC). ) 22 to form a square wave, which is applied to the gate circuit (hereinafter referred to as GAT) 23, while the gate pulse generation circuit (hereinafter referred to as GP) generated based on the operation of the printing machine.
The GAT23 is controlled by the gate pulse from the G) 24, and the counter (hereinafter, CUT) 26 that counts the clock pulses from the clock pulse generator (hereinafter, GLG) 25 is reset, and the GPG 24 detects each color. The gate pulse is generated from the detection start point corresponding to the reference point, and the gate pulse generation is continued until detection of the register mark for each color is completed.
The detection output by 1 passes through the GAT 23 for each color and is given to the differentiating circuit (hereinafter, DEF) 27.

Then, the DEF 27 sends out a differential pulse corresponding to the leading edge or the trailing edge of the register mark for each color and gives it to the latch circuit (hereinafter referred to as LAT) 28, which holds the count value of the CUT 26, so that the gate pulse of the GPG 24 is generated. The count value of CUT26 which is reset at the same time as the start and restarts the counting of the clock pulse given from CLG25 is held by LAT28, and this shows the distance between the detection reference point for each color and the register mark.

The GPG24 sends a clear pulse for each color immediately before the start of detection of each register mark to clear the LAT28. Therefore, the LAT28 first holds the distance between the detection reference point of the first color and the register mark. , The same distance of the second color is held, and thereafter, the same distances of the third color and thereafter are held in sequence.
C) 29 is sequentially given to the OPC 29, and the OPC 29 performs the later-described calculation and outputs the output signal S _D indicating the corrected target value.

FIG. 1 is a diagram showing a situation in which a correction reference point is set as a premise for obtaining a correction target value. The distance between the detection reference point for each color and the register mark is a specified distance if the register error is zero. The registration error distributions of the first color, the first color, the seventh color, and the seventh color are obtained as shown in FIG. 1 by the deviation of the measured distance that reaches the specified distance.

Note that the OPC29 is composed of a processor (hereinafter, CPU), memory, etc., and executes the instructions stored in the memory by the CPU.
Is executed and the arithmetic processing is performed while accessing the required data to the memory. In FIG. 1, the first color · 1 is used as the specific color and the first color · 1 is used as a reference. Register error amount E _{2 to} E ₇ between other colors and 2 to ₇
For each individual, and the maximum positive error amount Emax ₁
And the maximum negative direction error amount Emax ₂ as E ₅ and E ₆ , By the calculation of, the middle of E ₅ and E ₆ is obtained as the corrected reference point E _F.

Therefore, if the correction target value for each color and 1 to 7 is calculated according to the correction reference point E _F , the correction direction will be focused on the center correction reference point E _F , and the correction status of the register adjustment will be the fastest. Become.

FIG. 3 is a flow chart of the arithmetic processing status by the CPU in the OPC 29, and in the case of double-sided printing, for example, “Error amount E _{2 to} En of each color is determined with reference to the first upper surface color and stored in memory”.
101, perform “determine the maximum positive direction error amount E _max1 ” from E _{2 to} En 102, and similarly, perform the “negative direction maximum error amount E _max2
From the finding "103 rows of connexion, (1) calculated by performs calculation" 111 to "E _{F of, E ir = E i -E F} (i = 1~n) using the same ... (2) after "to obtain a correction amount of error E _1r to E _nr" 112 was row summer by the operation of, after the "corrected target value calculation" 113 for each color was rows summer based on this, step 101 after through the "RET" Is repeated.

The correction target value is determined according to the measured distance between the detection reference point for each color and the register mark, and this correction target value is sent as an output signal S _D (S _{D1 to} S _Dn ) for each color, Since the motors for adjusting the register of the plate cylinder are applied almost at the same time, the register adjustments of the respective colors are performed almost simultaneously in the direction of focusing on the corrected reference point E _{F in} FIG.

Therefore, the correction amount of the register adjustment is the maximum in the fifth color, the fifth color, and the sixth color, but the correction amount is averaged in general, and the correction amount is larger than that when the first color is set to 1 as a reference. The maximum correction amount is reduced, registration adjustment is speeded up, and the number of defective sheets generated during this period is greatly reduced.

However, it is also possible to determine the amount of error with each color based on other colors without using the first color and 1 as a specific color, and if the detection site by LES21 is selected according to the shape of the register mark, it is only in the vertical direction. Instead, the register adjustment in the left-right direction can be similarly performed.

Further, in FIG. 2, the functions of GAT23, CUT26 to LAT28 may be accommodated in the OPC 29 and realized by a CPU, or the OPC 29 may be configured by combining various logic circuits, and the like. Can be freely transformed.

〔The invention's effect〕

As is apparent from the above description, according to the present invention, the correction amount of the register adjustment is averaged, the register adjustment is not performed more than necessary, and the time required is shortened, so that the generation amount of defective paper is significantly reduced. A remarkable effect can be obtained in register adjustment used for various multicolor printing.

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention. FIG. 1 is a diagram of a situation in which a correction reference point is set, FIG. 2 is a block diagram of an electric circuit, and FIG. 3 is a flow chart of arithmetic processing. 1 to 7 ... 1st color to 7th color, 21 ... LES (photoelectric sensor), 26 ... CUT (counter), 27 ... DEF (differential circuit), 28 ... LAT (latch circuit), 29 ... … OPC (arithmetic circuit), E _{1 to} E ₇ …… Registration error amount, E _F …… Correction reference point.

Claims (1)

[Claims] 1. A register mark for each color is detected,
A method of automatically performing register adjustment between each on the basis of the detection output color, determined the in parentheses misregister amount E ₂ to E _n between the other colors specific color as a reference in each color, and Then, the positive direction maximum error amount E _max1 and the negative direction maximum error amount E _max2 are obtained from the respective error amounts, and the intermediate value between the positive direction maximum error amount E _max1 and the negative direction maximum error amount E _max2 , that is, (E _max1 + E _max2 ) / 2 as the correction reference point E _F, and E _ir = E _i −E _F (i = 1 to n) to obtain the correction error amount E _{ir to} En _r for each color, and the correction error amount E _{ir to} En _r The correction target values S _{D1 to} S _Dn for each color are obtained based on the above, and the registration standard of the automatic register adjustment is characterized in that the register adjustments of the respective colors are performed almost simultaneously according to the correction target values S _{D1 to} S _Dn. Point setting method.