JPH0784054B2 - How to select the correction reference color for automatic register adjustment - Google Patents

Description

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

[Conventional technology]

In a multicolor printing machine such as a rotary printing machine, printing paper, blanket, the quality of printing materials such as ink, and the tension applied to the paper, the register between the colors varies according to the change in printing conditions such as ink tack, For the purpose of automatically detecting this and correcting the register error between the respective colors, the method disclosed in Japanese Patent Application Laid-Open No. 58-14751 filed by the applicant of the present application is gradually spreading.

[Problems to be solved by the invention]

However, conventionally, the register mark printed for each color is detected, and the registration error between the colors is obtained based on the detected forces. When the registration error is obtained, the reference color is the first color. Alternatively, the color is fixed to the second color, or a staff member selects a specific color from each color, and the register mark printing status based on this fixedly set color is used as a reference, and the register error amount between the colors is generally determined. As you can see, this fixed color is not the center of the error occurrence distribution situation,
In addition to occasions when more than necessary corrections are made, control time by motor drive is used for register adjustment, so the time required for corrections is long, and every time corrections are made more than necessary, defective paper such as duplicate printing is It occurred in large quantities and was a problem that was uneconomical.

[Means for solving problems]

In order to solve the above problems, the present invention is configured by the following means.

That is, in the method for automatically performing the above-mentioned register adjustment, the register error amount between each of the other colors is determined based on the specific color in each color, and each register error amount is counted to be equal to or less than the allowable error, The specific color is sequentially changed to another color to obtain each register error amount and the count is performed for each individual, and the correction target values based on the register error amount are all within the adjustment allowable range and the count value becomes maximum. At this time, the color used as the specific color is selected as the reference color, and the register adjustment is performed according to the reference color.

[Work]

Therefore, according to the error occurrence distribution status of each color, the correction status is minimum, and the reference color whose correction value is within the adjustment allowable range is automatically selected, and the register adjustment is performed in the direction of focusing. Therefore, the optimum correction is most efficiently performed.

〔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 gives a square wave to a gate circuit (hereinafter referred to as GAT) 23, while a gate pulse generation circuit (hereinafter referred to as GPG) 2 generated based on the operation of the printing machine 2
The GAT23 is controlled by the gate pulse from 4 and the counter (hereinafter, CUT) 26 that counts the clock pulses from the clock pulse generator (CLG) 25 is reset, and the GPG24 is the detection reference point for each color. The gate pulse is generated from the detection start point corresponding to the above and continues to be generated until the detection of the register mark is completed for each color.Therefore, the detection force by LES21 of each register mark is set to GAT23 for each color. It passes and is given to the differentiating circuit (hereinafter, DEF) 27.

Then, DEF27 sends out the differential pulse corresponding to the leading edge or the trailing edge of the register mark for each color, and the latch circuit (hereinafter,
LAT) 28 to hold the count value of CUT26, so that the count value of CUT26 which is reset at the same time as the start of the gate pulse generation of GPG24 and restarts the clock pulse count given from CLG25 is held by LAT28. It indicates the distance between each detection reference point 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 for the second color is held, and thereafter, the same distance for the third color and thereafter is held in sequence, and these are the arithmetic circuit (OPC) 2
Then, the OPC 29 performs the calculation described below 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 color is selected 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 distribution of the first color, the first color, the fourth color, and the fourth color is obtained as shown in FIG. 1 by the deviation of the measured distance from the specified distance.

The OPC29 is composed of a processor (hereinafter, CPU) and memory, and the CPU executes instructions stored in the memory and performs arithmetic processing while accessing the necessary data to the memory. In FIG. 1, for example, first, as a specific color, the registration error amount E _{11 to} E ₁₄ between the first color 1 and each color 1 to 4 as a reference (Note; E ₁₁ =
0) is obtained for each individual, and those having an allowable error x or less determined according to printing conditions are selected from these register error amounts E _{11 to} E ₁₄ and the number is counted to obtain a count value C ₁ , and at the same time, , The registration error amount E ₂₁ , E ₂₂ , E ₂₃ , E ₂₄ (Note; E ₂₂ = 0) by the same judgment with the specific color as the second color · 2, for example.
And the count value C ₂ is obtained by the same count, and the specific color is changed to the third color, the third color, and the fourth color, 4 in sequence, and the respective register error amounts are obtained, and the same After the count values C ₃ and C ₄ are obtained by counting, the correction target value for register adjustment based on each register error amount for each specific color is within the adjustment allowable range W that is restricted by the mechanical conditions of the printing machine. It is determined whether or not the correction target value of each color is within the allowable range W and the count value is maximum, and then the color used as the specific color is selected, and this is used as the reference color. It is supposed to be used as.

Therefore, in FIG. 1, assuming that the third color and 3 satisfy the above-mentioned conditions, the register error amount exceeding x is extracted from each register error amount based on this condition, and correspondingly, By setting the correction target value for each color, 1, 2, 4
The correction direction is focused on the third color / third color, and the correction status of the register adjustment is the minimum necessary, optimal, and fastest.

FIG. 3 is a flow chart of the calculation processing status by the CPU in the OPC 29, and in the case of double-sided printing, for example, “Error amounts E _{11 to} E ₁ n of each color are determined with reference to the top first color and stored in memory”.
Performs 101, to which E ₁₁ to E ₁ n each per "Request count · C ₁ things E ₁₁ ~E ₁ n ≦ x" tolerance x the top of decision following ones based on 102 lines of connexion Then, the count value “C ₁ · Store in memory” 103 is performed, and the count value i of the count configured in the CPU to count the number of the specific color as the reference is changed to the second color · 2 by “i ← 2” 104. Set.

Then, as in steps 101 to 103, “Error amount E _ij (i = 1 to n, j = 1 to n) of each color is determined based on the i-th color and stored in memory” 111, “E _ij ≦ x Count things and get Ci ”112, and count value“ Ci, store in memory ”1
After performing step 13, the counter of the specific color number is incremented by "i ← i + 1" 114, and "i = n + 1?" 115 is N (NO).
In the meantime, step 111 and subsequent steps are repeated, and the second color, the third color to the nth color, and n are sequentially used as the specific color, and the same processing is performed for each.

Next, the count values C _{1 to} Cn in the memory are read out, and the “maximum count value / C _max ” is obtained by repeating mutual comparison.
121 is performed, and it is determined whether or not the value is “1” by “C _max = 1?” 122. If N, “C _max is multiple?” 12
Check 3 and when Y (YES), find the specific color m corresponding to each Cmax, and find the error amount E ₁ m when the upper surface first color corresponding to this specific color m is used as the reference. Perform "Store the error amount E ₁ m of the specific color m of each Cmax in the memory" 131a to store in memory, and repeat this comparison of E ₁ m to "E
Performs descending order sequence "131b to ₁ m, the center identified seek E ₁ i the size of the center, which select the middle E ₁ i of" E ₁ m to obtain a specific color i at that time, the corresponding “Determine color i” 131c is performed.
On the other hand, when step 123 is N, C _max is selected.
The specific color i is obtained ”132, and the specific color i when only one C _max is obtained is selected.

When the specific color i is selected by step 131 or 132,
The selected error amount E _{ij of} each color based on the i-th color
-"Read" 133 is performed from the memory, and "E _ij ≤
“Exclusion of x” 134 is performed, and then “correction target value calculation” 141 is performed according to each error amount E _ij exceeding the allowable error x and the current position of the plate cylinder register for each color. “Correction target value | ≦ W?” 142, it is judged whether or not the correction target value of each color is within the adjustment allowable range W, and if it is Y, the optimum reference color i is selected, and step 141 Value is sent as the output signal S _D , and then via “RET” the step 101
Repeat the above.

On the other hand, when the step 142 is N, the selection of the reference color is unsuitable and an uncorrectable color is generated, so that “C _max ←
0'151 clears C _max obtained in step 121 and then returns to step 121, where the next largest count value is obtained as a new C _max , and step 122 and subsequent steps are repeated.

On the other hand, when the step 122 is Y, the “reference color selection process when C _max = 1” 152 is performed as follows.

FIG. 4 is a flow chart showing the details of step 152. When C _max = 1 the error amount “E
" _1j read" 201 from the memory, and "E _1j are arranged in descending order" 202, each E _1j is sequentially stored in the memory by mutual comparison of each E _1j , and then "S ← n" 211 is used. The number n is used as the operation constant S, and only the integer is used as the reference color number T. The operation of “T = INT {(2S + 1) / 2}” 212 is performed, and the N of “T = 0?” 213 is assumed, and the T-th In big E ₁ j
Error amount Elj calculation based on the unit l corresponding to
Elj = E ₁ l−E ₁ j ...... (1), perform “Exclude Elj ≦ x” 222 from these, as in step 134, and then perform “correction target value calculation” as in step 141. In step 223, as in step 142, “all | corrected target value | ≦ W?” 224 is determined, and if this is Y, the value obtained in step 223 is sent as the output signal S _D , and then via “EXIT”. Move to "RET" in FIG.

On the other hand, when step 224 is N, E ₁ l is set to the minimum E ₁ j and E ₁ j of the size from the _1st to the nth is sequentially set by “arrangement of E _1j ” 231. To the upper position (this conceptual diagram is shown in FIG. 5), the arrangement of the step 202 is changed, S is subtracted by "S ← S-1" 232, and the step 212 transition is repeated until the step 224 changes to Y. If step 213 becomes Y before the above condition is reached, a display signal is sent to the display device omitted in FIG. 2 and "OVER ERROR" 241 is displayed.

Therefore, while Step 224 is N, T is changed by Step 232, and the operation of Step 221 is performed based on the Tth position according to the rank from the highest rank in E _{1j of} the array rank changed by Step 231. The correction target value is determined based on this, and if any color is inappropriate as the reference color, step 213 becomes Y,
It becomes "OVER ERROR".

Further, in FIG. 3, the maximum count value C _max is obtained by step 121, and a specific color whose correction target values are all within the adjustment permissible range W is selected as a reference color by step 142. At 134, E _ij
Since those of ≦ x are excluded, only the color of the error amount exceeding the allowable error x is subjected to the register adjustment, and the minimum necessary correction is optimally and swiftly made. In the case of FIG. It will be similar.

Therefore, compared to the case where one of the colors is fixed as the reference color, the general correction status becomes the minimum necessary, speeding up the register adjustment is realized, and the number of defective papers generated during this period is greatly reduced. .

However, the error amount with each color may be obtained with reference to other colors without first using the first color and 1 as a reference, or the error amount with respect to each other color may be obtained using one of the colors as a reference. It is the same as if only calculating, and calculating each error amount when other colors are used as a reference based on these error amounts, if the detection site by LES21 is selected according to the shape of the register mark, Not only the direction but also the lateral direction can be adjusted in the same manner.

Further, in FIG. 2, the functions of GAT23, CUT26 to LAT28 may be accommodated in the OPC 29 and realized by the CPU, or the OPC 29 may be configured by combining various logic circuits, and In FIGS. 3 and 4,
Depending on the situation, various modifications are possible, such as changing the steps, replacing them with other equivalent ones, or omitting unnecessary ones.

〔The invention's effect〕

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

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention, FIG. 1 is a diagram showing a situation in which a correction reference color is selected, FIG. 2 is a block diagram of an electric circuit, FIGS. 3 and 4 are flowcharts of arithmetic processing, and FIG. [FIG. 3] is an explanatory diagram of arrangement change. 1 to 4 ... 1st color to 4th color, 21 ... LES (photoelectric sensor), 26 ... CUT (counter), 27 ... DEF (differential circuit), 28 ... LAT (latch circuit), 29 ... … OPC (arithmetic circuit), E _{11 to} E ₁₄ , E ₂₁ to ₂₄ … Registration error amount.

Claims (1)

[Claims] 1. A register mark for each color is detected,
In a method of automatically performing register adjustment between the respective colors based on the detected forces, the register error amount between each of the other colors is obtained with reference to a specific color among the respective colors, and the register error amount. Is less than the permissible error amount, the specific color is sequentially changed to another color to obtain each register error amount and the count is performed for each, and when the count value reaches the maximum, A method for selecting a corrected reference color for automatic register adjustment, wherein a color used as a specific color is selected as a reference color and the register adjustment is performed according to the reference color.