Compensation primary color overprinting method based on printing material deformation

Abstract

The invention discloses a compensation primary color overprinting method based on printing material deformation. The compensation overprinting method for a roll-shaped base material printing machine with a plurality of color groups comprises the following steps that overprinting color codes and color code detection probes of color separation printing plates are arranged; detecting and calculating the positions and mutual distances of the overprinted color codes on the two sides of the printing material; calculating longitudinal and transverse overprinting deviations between the color cells; calculating the longitudinal and transverse deformation of the printing material between the color cells; and calculating the longitudinal and transverse overprinting adjusting quantities of the color cell. Through the steps, the problem of multicolor overprinting after the printing material is deformed is solved.

Description

Technical Field

[0001] The invention relates to printing press overprinting technology, in particular to a compensating base color overprinting method based on the deformation amount of printing material. Background Art

[0002] When a multi-color web-fed gravure printing machine performs color overprinting, the usual practice is to set a printing overprint color mark in the empty area outside one side of the printed image, set a color mark detection probe behind the color separation plates of the second color to the last color of the printing machine, set an encoder on the color separation plate drive motor, read the number of pulses detected by each color mark probe when the real color overprint color mark and the overprint color mark of the previous color arrive and leave, calculate the difference between the two pulses at the corresponding positions, and obtain the registration difference between the color where the probe is located and the previous color, and drive the printing plate motor with a computer to perform registration compensation. However, the existing technology lacks consideration of the deformation of the printing material, and there is no detection and measurement method for the deformation of the printing material, and there is no calculation method for the overwriting adjustment amount of the superimposed deformation. Therefore, for printing materials with large deformation, the current multi-color overprinting method is not applicable. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a method for compensating primary color overprinting based on the deformation of a printing material, so as to solve the problem of multi-color overprinting with deformation of the printing material.

[0004] In order to solve the above technical problems, the technical solution of the present invention is: a compensating primary color overprinting method based on the deformation of the printing material, the compensating overprinting method for a roll substrate printing machine with multiple color groups comprises the following steps:

[0005] 1) Set the overprint color mark and color mark detection probe of the color separation printing plate:

[0006] A left and right overprint color mark is set outside the two sides of the image and text of the 1st to Mth color separation printing plates to be overprinted, respectively. The center line of the overprint color marks on the left and right sides of each color separation printing plate is symmetrical to the longitudinal center line of the printing plate. The longitudinal distances of the overprint color marks of different color separation printing plates are the same and equal to the set plate overprint color mark distance; a group of two color mark detection probes is set behind each color separation printing plate to detect the overprint color marks on the left and right sides of the printing material respectively, and an encoder that can be linked with the color mark detection probe for output is set on the driving motor of each color separation printing plate;

[0007] 2) Detect and calculate the position and mutual distance of the overprint color marks on both sides of the printing material:

[0008] In the multi-color overprinting process, the color mark detection probe is used to detect the color separation plates of the 1st to Mth colors, and the repeated overprint color marks including the left and right sides of the 1st to Mth colors are printed on both sides of the printing material. The encoder corresponding to the color separation plate driving motor is used to record the time when the color mark is in place and leaves, and the built-in program is input to calculate the following parameters:

[0009] 2.1) Detect the width of the left and right overprint color marks of the color group and the first color group of the color separation printing plate where the color mark detection probe is located within the same plate diameter printing width on the printing material, and mark the longitudinal detection height of the left and right overprint color marks of the base color overprint of the color;

[0010] 2.2) Detect the respective longitudinal distances between the color group of the color separation printing plate where the color mark detection probe is located and the left and right overprint color marks of the first color group within the same plate diameter printing width on the printing material, and mark it as the longitudinal detection distance between the left and right color marks of the base color overprint of the color;

[0011] 2.3) Detect the longitudinal distance between the overprint color marks of the color separation printing plates where the color mark detection probes of each group on the printing material are located within two adjacent plate diameter printing widths, and mark them as the plate length detection length on the left and right sides of the color.

[0012] 3) Calculate the vertical and horizontal overprint deviation between color groups:

[0013] 3.1) Subtract the left and right longitudinal detection distances between the color marks of the primary color overprints of the second to the Mth colors from the multiples of the plate overprint color mark length, and the difference is the left and right longitudinal overprint deviation of the color relative to the reference printing color group, and the multiple is the difference between the color sequence and the first color, and is marked as the left and right longitudinal overprint deviation of the primary color overprint of the color; the conversion coefficient is related to the pattern of the overprint color mark;

[0014] 3.2) Subtract the longitudinal detection heights of the two overprint color marks on the left side of each color, and multiply the difference by the conversion coefficient to get the horizontal overprint deviation on the left side; subtract the longitudinal detection heights of the two overprint color marks on the right side of each color, and multiply the difference by the conversion coefficient to get the horizontal overprint deviation on the right side. The two horizontal overprint deviations are respectively marked as the left and right horizontal overprint deviations of the base color overprint of the color.

[0015] 4) Calculate the longitudinal and lateral deformation of the printing material between color groups:

[0016] 4.1) Subtract the plate length detection length on the left and right sides of a certain color from the plate diameter circumference of the color printing plate to obtain the longitudinal deformation of the plate diameter circumference of the printing material on the printing material between the current color group and the next color group, multiply the difference by the ratio of the plate overprinting color scale length to the plate diameter circumference of the color printing plate, and the value is the equivalent longitudinal deformation of the color scale length on the left and right sides of the next color of the color, add the equivalent longitudinal deformation of the color scale length on the left and right sides of all the color separation plates before the certain color, and mark it as the cumulative color scale length longitudinal deformation on the left and right sides of the base color overprint of the color;

[0017] 4.2) Subtract the lateral overprint deviations of the left and right color marks of a certain color base color overprint to obtain the lateral deformation of the left and right overprint color mark spacing between the true color group and the first color group of the printing material, and mark it as the lateral deformation of the left and right color mark spacing of the color base color overprint;

[0018] 5) Calculate the vertical and horizontal overprint adjustment of the color group:

[0019] 5.1) Subtract the average value of the longitudinal deformation of the left and right color scales of the base color overprint of the original color from the average value of the longitudinal overprint deviation of the left and right sides of the base color overprint of a certain color, and the result is the longitudinal adjustment value of the base color overprint of the color;

[0020] 5.2) Subtract half of the lateral deformation of the left and right color mark spacing of the primary color overprint from the overprint deviation on the left side of the primary color overprint of the Nth (2≤N) color, and the result is the lateral adjustment value of the primary color overprint of the Nth color;

[0021] 6) The longitudinal adjustment value of the primary color overprinting from the second to the Mth color and the lateral adjustment value of the primary color overprinting are input into the overprinting control program as feedback values ​​to control the rotation speed of the transmission motor of each color separation printing plate and adjust the relative position of each color separation printing plate.

[0022] As an improvement, when the primary color overprinting mode is adopted, the longitudinal adjustment amount R of the primary color overprinting of the first color unit by the Nth color unit is Vn1 And the horizontal adjustment amount R of the base color overprint Cn1 The calculation formula is as follows:

[0023] R Vn1 =0.5* [ΔF nl +ΔF nr ] -0.5 *[∑ζL e (n-1)1l +∑ζL e (n-1)1r ] mm (1)

[0024] R Cn1 =δC nl - 0.5*ζC n1 mm (2)

[0025] When R Vn1 When the calculated value is positive, the Nth color group motor accelerates relative to the 1st color group motor, and when it is negative, it decelerates.

[0026] When R Cn1 When the calculated value is positive, the color plate of the Nth color group moves to the left relative to the color plate of the 1st color group, and when it is negative, it moves to the right;

[0027] ΔF nl and ΔF nrThe left and right longitudinal overprint deviations of the base color overprint of the Nth color;

[0028] δC nl and δC nr The left and right lateral overprint deviations of the base color overprint of the Nth color;

[0029] ∑ζL e(n-1)1l and ∑ζL e(n-1)1r It is the cumulative longitudinal deformation of the color scale length on the left and right sides of the primary color overprint of the (N-1)th color;

[0030] ζC n1 It is the lateral deformation of the distance between the left and right color labels of the Nth color.

[0031] As an improvement, it is calculated according to the following formula:

[0032] ΔF nl = F nl - (n-1)*L e mm (3)

[0033] ΔF nr = F nr - (n-1)*L e mm (4)

[0034] δC nl =[h nl -h 1l ]*I mm (5)

[0035] δC nr =[h nr -h 1r ]*I mm (6)

[0036]

[0037] ζC n1 =δC nl -δC nr mm (9)

[0038] F nl and F nr are the vertical detection distances between the color marks of the primary color overprints on the left and right sides of the Nth color; h nl 、h nr 、h 1l and h 1r The vertical detection heights of the overprint color marks on the left and right sides of the base color overprint of the Nth color respectively;

[0039] zeL e(n-1)l and ζL e(n-1)r It is the equivalent longitudinal deformation of the left and right color scale lengths of the primary color overprint of the (N-1)th color to the Nth color;

[0040] Le is the distance of the color mark of the printing plate, set as a constant, and take 20mm;

[0041] I is the conversion factor between the center height and width of the bidirectional overprint color mark. For the wedge-shaped mark, I=W / (H B -H T );W is the length of the wedge mark, H B and H T Mark the heights of the upper and lower bases of the wedge respectively.

[0042] As an improvement, it is calculated according to the following formula:

[0043] F nl = V n *[t nn1l -t n11l ] mm (10)

[0044] F nr = V n *[t nnlr -t n11r ] mm (11)

[0045] h 1l = V n *[t n12l -t n11l ] mm (12)

[0046] h 1r = V n *[t n12r -t n11r ] mm (13)

[0047] h nl = V n *[t nn2l -t nn1l ] mm (14)

[0048] h nr = V n *[t nn2r -t nn1r ] mm (15)

[0049] zeL e (n-1)l =ΔS (n-1)l *L e / S P(n-1) mm (16)

[0050] zeL e (n-1)r =ΔS (n-1)r *L e / SP(n-1) mm (17)

[0051] ΔS (n-1)l and ΔS (n-1)r S are the longitudinal deformation of the left and right plate diameters of the (N-1)th color respectively; P(n-1) It is the circumference of the printing plate of the (N-1)th color.

[0052] As an improvement, it is calculated according to the following formula:

[0053] S P(n-1) =πd+(n-1)Δd mm (18)

[0054] ΔS (n-1)l =S (n-1)l -S P(n-2) mm (19)

[0055] ΔS (n-1)r =S (n-1)r -S P(n-2) mm (20)

[0056] S (n-1)l and S (n-1)r The length of the left and right sides of the plate length for the (N-1)th color of the base color overprint.

[0057] d is the nominal diameter of the printing plate, in mm;

[0058] Δd is the incremental increase in the plate diameter of the (N-1)th color, in mm;

[0059] n∈[2,m], m is the number of printing color groups.

[0060] As an improvement, it is calculated according to the following formula:

[0061] S (n-1)l =V (n-1) *{[Nt (n-1)(n-1)1l ]-t (n-1)(n-1)1l mm (21)

[0062] S (n-1)r =V (n-1) *{[Nt (n-1)(n-1)1r ]-t (n-1)(n-1)1r mm (22)

[0063] V n and V (n-1) It is the color separation plate speed value when the color mark of the Nth and (N-1th) colors are detected.

[0064] As an improvement, it is calculated according to the following formula:

[0065] V n=1.5708d n *[t znn2l -t znn1l ] mm / s (23)

[0066] V (n-1) =1.5708d (n-1) *[t z(n-1)(n-1)2l -t z(n-1)(n-1)1l ]mm / s (24)

[0067] t n(n-1)1l It is the time value when the left color mark detection probe of the Nth color reads the color mark of the (N-1)th color group entering;

[0068] t n(n-1)2r The time value when the color mark detection probe on the right side of the Nth color reads the color mark of the (N-1)th color group leaves;

[0069] [Nt (n-1)(n-1)1r ] is the time value when the right color mark detection probe of the (N-1)th color reads the color mark of the (N-1)th color group for the second time;

[0070] The meanings of the other time symbols are similar.

[0071] t znn2l The Z pulse moment of the encoder when the color mark detection probe on the left side of the Nth color reads the end of N color marks;

[0072] t znn1l The Z pulse moment of the encoder when the vehicle probe reads the color mark on the left side of the Nth color to the beginning of the Nth color mark.

[0073] As an improvement, the printing press is provided with a total of N color groups, each color group includes a color separation plate, a color separation plate drive motor, an encoder, a color mark detection probe, a high-frequency counter and an operation controller. The high-frequency counter reads the output signals of the color mark detection probe and the encoder and records the signals through pulse signals. The operation controller collects signals, calculates and analyzes the longitudinal and lateral overprint deviations of each two colors through a control program and issues adjustment instructions.

[0074] Compared with the prior art, the present invention has the following beneficial effects:

[0075] Set the overprint color marks on the left and right sides of the color separation printing plate and the color mark detection probes on both sides; detect and calculate the position and mutual distance of the overprint color marks on both sides of the printing material through the preset control program; not only can calculate the longitudinal and transverse overprint deviation between the color groups; but also calculate the longitudinal and transverse deformation of the printing material between the color groups; and then subtract the longitudinal and transverse deformation from the overprint deviation when calculating the longitudinal and transverse overprint adjustment of the color group, so as to improve the overprint accuracy of the printed product; the present invention solves the problem of multi-color overprinting after the printing material is deformed through the above steps. And provide the longitudinal and transverse deformation values ​​to another control program as a control target and input for reducing the deformation of the printed product. BRIEF DESCRIPTION OF THE DRAWINGS

[0076] Figure 1 This is a schematic diagram of the base color overprinting color standard setting and calculation.

[0077] Figure 2 Schematic diagram of color scale setting and calculation for longitudinal deformation error detection.

[0078] Figure 3 Schematic diagram of a multi-color printing press. DETAILED DESCRIPTION

[0079] The present invention will be further described below in conjunction with the accompanying drawings.

[0080] A compensating primary color overprinting method based on the deformation of the printing material, such as Figure 3 As shown, it is realized based on a multi-color group roll substrate printing machine, and the printing machine is provided with a total of M color groups, each color group includes a color separation printing plate 1, a color separation printing plate driving motor and its controller 6, an encoder 2, a color mark detection probe 3, a high-frequency counter 4 and an operation controller 5. Two color mark detection probes 3 are located at opposite positions on both sides of the printing material 7 passing through the color separation printing plate 1, and encoders are installed on the color separation printing plate driving motor shafts of the 1st to Mth color groups; a high-frequency counter and an operation controller are installed in the control circuit of each color group, and the color mark detection probe captures the overprint color marks on both sides of the printing material; the high-frequency counter reads the output signals of the color mark detection probe and the encoder and records the signals through pulse signals, and the operation controller collects signals, calculates and analyzes the longitudinal and lateral overprint deviations of each two colors through the control program and issues adjustment instructions.

[0081] Figure 1The schematic diagram of the color mark setting and calculation principle of the base color overprinting is shown in the figure. The figure lists four repeated substrate plate diameter print widths 1 to 4 printed by the color separation printing plate on the printing material. These print widths are not connected end to end in the actual printing material roll. In order to facilitate the explanation of the technical principle, the inventor puts them in one figure for introduction. The substrate plate diameter print width 1 is the color mark information detected by the color mark probe 3 set in the first color group. The substrate plate diameter print width 1 only has the left color mark 11 and the right color mark 21 of the first color group. The time when the left color mark 11 and the right color mark 21 are read by the first color group probe to enter and leave is (t 111l , t 112l ), (t 111r , t 112r ); the substrate plate diameter print width 2 is the color mark information detected by the color mark probe 3 set in the second color group. The substrate plate diameter print width 2 has a left color mark 11 and a right color mark 21 of the first color group, a left color mark 12 and a right color mark 22 of the second color group. The time when the left color mark 11 and the right color mark 21 are read by the second color group probe to enter and leave is (t 211l , t 212l ), (t 211r , t 212r ), the time when the left color mark 12 and the right color mark 22 are read by the second color group probe to enter and leave are (t 221l , t 222l ), (t 221r , t 222r ); the substrate plate diameter print width 3 is the color mark information detected by the color mark probe 3 set in the third color group. The substrate plate diameter print width 3 has a left color mark 11 and a right color mark 21 of the first color group, a left color mark 12 and a right color mark 22 of the second color group, and a left color mark 13 and a right color mark 23 of the third color group. The time when the left color mark 11 and the right color mark 21 are read by the third color group probe to enter and leave is (t 311l , t 312l ), (t 311r , t 312r ), the time when the left color mark 13 and the right color mark 23 are read by the third color group probe to enter and leave are (t 331l , t 332l ), (t 331r , t 332r); the substrate plate diameter print width 4 is the color mark information detected by the color mark probe 3 set in the Nth color group. The substrate plate diameter print width 4 has a left color mark 11 and a right color mark 21 of the first color group, a left color mark 12 and a right color mark 22 of the second color group, a left color mark 13 and a right color mark 23 of the third color group, a left color mark 14 and a right color mark 24 of the (N-1)th color group, and a left color mark 15 and a right color mark 25 of the Nth color group. The time when the left color mark 11 and the right color mark 21 are read by the Nth color group probe to enter and leave is [t n11l , t n12l ],[t n11r , t n12r ], the time when the left color mark 15 and the right color mark 25 are read by the Nth color group probe to enter and leave are (t nn1l , t nn2l ), (t nn1r , t nn2r ).

[0082] Figure 2 Schematic diagram of the position of color mark for detecting longitudinal deformation error, which lists six repeated substrate plate diameter print widths 1 to 6 printed by the color separation printing plate on the printing material, wherein the substrate plate diameter print width 1 and the substrate plate diameter print width 2 are two substrate plate diameter print widths after the color separation printing plate of the first color group connected end to end through the color mark probe of the first color group, the substrate plate diameter print width 3 and the substrate plate diameter print width 4 are two substrate plate diameter print widths after the color separation printing plate of the second color group connected end to end through the color mark probe of the second color group, the substrate plate diameter print width 5 and the substrate plate diameter print width 6 are two substrate plate diameter print widths after the color separation printing plate of the (N-1)th color group connected end to end through the color mark probe of the (N-1)th color group, Figure 2 Medium (t 111l , Nt 111l ) and (t 111r , Nt 111r ) is the time when the color mark probe of the first color group detects the left and right color marks of the first color group within two consecutive printing widths. Figure 2 Medium (t 221l , Nt 221l ) and (t 221r , Nt 221r ) is the time when the color mark probe of the second color group detects the left and right color marks of the second color group within two consecutive printing widths of the plate diameter, Figure 2 In (n-1)(n-1)1l , Nt (n-1)(n-1)1l ] and [t (n-1)(n-1)1r , Nt (n-1)(n-1)1r ] is the time when the color mark probe of the first color group detects the left and right color marks of the first color group within two consecutive plate diameter printing widths.

[0083] like Figure 2 ,3 As shown, the method for compensating primary color overprinting based on the deformation of the printing material includes the following steps:

[0084] 1) Set the overprint color mark and color mark detection probe of the color separation printing plate:

[0085] Left and right overprint color marks 11 to (10+M) and 21 to (20+M) are respectively arranged outside the two sides of the image and text of the 1st to Mth color separation printing plates 1 to be overprinted, the center line of the overprint color marks on the left and right sides of each color separation printing plate is symmetrical to the longitudinal center line of the printing plate, and the longitudinal distances of the overprint color marks of different color separation printing plates are the same and equal to the set overprint color mark distance of the printing plate; a group of two color mark detection probes 3 are arranged behind each color separation printing plate to respectively detect the overprint color marks on the left and right sides of the printing material, and respectively detect the overprint color marks on the left and right sides of the printing material, and an encoder 2 and a high-speed counter 4 that can be linked with the color mark detection probe for output are arranged on the driving motor of each color separation printing plate;

[0086] 2) Detect and calculate the position and mutual distance of the overprint color marks on both sides of the printing material:

[0087] In the multi-color overprinting process, the color mark detection probe is used to detect the color separation plates of the 1st to Mth colors, and the repeated overprint color marks including the left and right sides of the 1st to Mth colors are printed on both sides of the printing material. The encoder corresponding to the color separation plate driving motor is used to record the time when the color mark enters and leaves, and the built-in program is input to calculate the following parameters:

[0088] 2.1) Detect the time values ​​of the color group of the color separation printing plate where the color mark detection probe is located and the left and right overprint color marks of the first color group within the same plate diameter printing width on the printing material, and calculate the longitudinal width h of the four color marks in total, front, back, left and right, by multiplying the time difference and the motor speed. nl 、h nr 、h (n-1)l and h (n-1)r And mark the vertical detection height of the overprint color mark on the left and right sides of the base color overprint of the color;

[0089] 2.2) Detect the time difference between the color group of the color separation printing plate where each group of probes is located and the left and right overprint color marks of the first color group within the same plate diameter printing width on the printing material, and multiply it by the motor speed value to obtain the respective longitudinal distances F between the left and right color marks and the first color mark. nl , F nr And mark the vertical detection distance between the color marks on the left and right sides of the base color overprint of the color;

[0090] 2.3) Detect the time difference when the overprint color marks of the color separation printing plate where the detection probe is located on the printing material enters the two adjacent plate diameter printing widths, and multiply it by the motor speed value to obtain the longitudinal distance S of the same color mark on the left and right sides.(n-1)l and S (n-1)r , and marked as the length of the left and right sides of the color.

[0091] 3) Calculate the vertical and horizontal overprint deviation between color groups:

[0092] 3.1) Subtract the left and right longitudinal detection distances between the color marks of the primary color overprints from the second color to the Mth color from the multiples of the overprint color mark length of the printing plate, and the difference is the left and right longitudinal overprint deviation ΔF of the color relative to the reference printing color group. nl , ΔF nr , the multiple is the difference between the color ranking and the first color, and is marked as the left and right vertical overprint deviation of the base color overprint of the color;

[0093] 3.2) Subtract the vertical detection heights of the two front and back overprint color marks on the left side of each color, and multiply the difference by the conversion coefficient to get the horizontal overprint deviation δC on the left side. nl ; Subtract the vertical detection heights of the two overprint color marks on the right side of each color, and multiply the difference by the conversion coefficient to get the horizontal overprint deviation δC on the right side. nr , and mark the two horizontal overprint deviations as the left and right horizontal overprint deviations of the base color overprint of the color.

[0094] 4) Calculate the longitudinal and lateral deformation of the printing material between color groups:

[0095] 4.1) Subtract the plate length detection length on the left and right sides of a color from the plate diameter circumference of the color to obtain the longitudinal deformation ΔS of the plate diameter circumference of the printing material on the printing material between the current color group and the next color group. (n-1)l , ΔS (n-1)r The difference is multiplied by the ratio of the color scale length of the printing plate to the circumference of the printing plate diameter of the color. This value is the equivalent longitudinal deformation of the color scale length on the left and right sides of the next color ζL e(n-1)l , ζL e(n-1)r , add up the equivalent longitudinal deformation of the color scale lengths on the left and right sides of all the color separation plates before a certain color, and mark it as the cumulative longitudinal deformation of the color scale lengths on the left and right sides of the base color overprint of the color ∑ζL e(n-1)l ,∑ζL e(n-1)r ;

[0096] 4.2) Subtract the lateral overprint deviation of the left and right color marks of a certain base color overprint to obtain the lateral deformation ζC of the spacing between the left and right overprint color marks of the printing material between the true color group and the first color group. n1 , and marked as the lateral deformation of the left and right color mark spacing of the base color overprint;

[0097] 5) Calculate the vertical and horizontal overprint adjustment of the color group:

[0098] 5.1) Subtract the average value of the longitudinal deformation of the left and right color scales of the base color overprint of the original color from the average value of the longitudinal overprint deviation of the left and right sides of the base color overprint of a certain color, and the result is the longitudinal adjustment value R of the base color overprint of the color. Vn1 ;

[0099] 5.2) Subtract half of the horizontal deformation of the left and right color mark spacing of the primary color overprint from the overprint deviation on the left side of the Nth (2≤N) primary color overprint. The result is the horizontal adjustment value R of the primary color overprint of the Nth color. Cn1 ;

[0100] 6) The longitudinal adjustment value of the primary color overprinting from the second to the Mth color and the lateral adjustment value of the primary color overprinting are input into the overprinting control program as feedback values ​​to control the rotation speed of the transmission motor of each color separation printing plate and adjust the relative position of each color separation printing plate.

[0101] The calculation process of base color overprinting based on the deformation of the printing material:

[0102] S1: Calculate the V according to formulas (23) and (24) n and V (n-1) Speed ​​value of each plate roller at the time of color mark detection:

[0103] V n =1.5708d n *[t znn2l -t znn 1l ] mm / s (23)

[0104] V (n-1) =1.5708d (n-1) *[t z(n-1) (n-1)2l -t z(n-1) (n-1)1l ] mm / s (24)

[0105] t znn2l The Z pulse moment of the encoder when the left color mark detection probe of the Nth color reads the end of N color marks;

[0106] t znn1l The Z pulse moment of the encoder when the left color mark detection probe of the Nth color reads the beginning of N color marks;

[0107] [t z(n-1)(n-1)2l ] is the Z pulse moment of the encoder when the left color mark detection probe of the Nth color finishes reading (N-1) color marks;

[0108] [t z(n-1)(n-1)1l ] is the Z pulse moment of the encoder when the left color mark detection probe of the Nth color starts to read the (N-1)th color mark;

[0109] d n and d (n-1) is the actual diameter of the Nth and (N-1)th color separation printing plates.

[0110] d n =d+(n-1)*Δd

[0111] d is the nominal diameter of the printing plate, in mm;

[0112] Δd is the incremental increase in the plate diameter of the (N-1)th color, in mm;

[0113] n∈[2,m], m is the number of printing color groups;

[0114] S2: Calculate the longitudinal detection distance between the color marks on the left and right sides of the Nth color base color overprint according to formulas (10) and (11):

[0115] F nl = V n *[t nn1l -t n11l ] mm (10)

[0116] F nr = V n *[t nnlr -t n11r ] mm (11);

[0117] t nn1l and t nn1r The time when the left and right overprint color marks of the Nth color enter as detected by the color mark probe of the Nth color group;

[0118] t n11l and t n11r The time when the left and right overprint color marks of the first color detected by the color mark probe of the Nth color group enter;

[0119] S3: Calculate the vertical detection height of the overprint color mark on the left and right sides of the Nth color base color overprint according to formulas (12), (13), (14) and (15):

[0120] h 1l = V n *[t n12l -t n11l ] mm (12)

[0121] h 1r = V n *[t n12r -t n11r ] mm (13)

[0122] h nl = Vn *[t nn2l -t nn1l ] mm (14)

[0123] h nr = V n *[t nn2r -t nn1r ] mm (15)

[0124] t n12l and n11l The time when the left overprint color mark of the first color detected by the color mark probe of the Nth color group leaves and enters;

[0125] t n12r and n11r The time when the right overprint color mark of the first color detected by the color mark probe of the Nth color group leaves and enters;

[0126] t nn2l and nn1l The time when the left overprint color mark of the Nth color detected by the color mark probe of the Nth color group leaves and enters;

[0127] t nn2r and nn1r The time when the right overprint color mark of the Nth color detected by the color mark probe of the Nth color group leaves and enters;

[0128] S4: Calculate the left and right longitudinal overprint deviations of the primary color overprint of the Nth color according to formulas (3) and (4):

[0129] ΔF nl =F nl -(n-1)* L e mm (3)

[0130] ΔF nr =F nr - (n-1)*L e mm (4);

[0131] S5: Calculate the left and right lateral overprint deviations of the base color overprint of the Nth color according to formulas (5) and (6):

[0132] δC nl =[h nl -h 1l ]*I mm (5)

[0133] δC nr =[h nr -h 1r ]*I mm (6);

[0134] I is the conversion factor between the center height and width of the bidirectional overprint color mark. For the wedge-shaped mark, I=W / (H B -H T );W is the length of the wedge mark, H B and H T They are the heights of the upper and lower bases of the wedge-shaped mark respectively; different values ​​are used for other types of bidirectional overprint color marks;

[0135] S6: Calculate the left and right plate length detection lengths of the (N-1)th color of the base color overprint according to formulas (21) and (22):

[0136] S (n-1)l = V (n-1) *{[Nt (n-1) (n-1)1l ]-t (n-1) (n-1)1l mm (21)

[0137] S (n-1)r = V (n-1) *{[Nt (n-1) (n-1)1r ]-t (n-1) (n-1)1r} mm (22);

[0138] [t (n-1)(n-1)1l ] and [Nt (n-1)(n-1)1l ] is the time when the left overprint color mark of the (N-1)th color detected by the color mark probe of the (N-1)th color group enters into two adjacent plate diameter printing widths for the first and second time;

[0139] [t (n-1)(n-1)1r ] and [Nt (n-1)(n-1)1r ] is the time when the right overprint color mark of the (N-1)th color detected by the color mark probe of the (N-1)th color group enters into two adjacent plate diameter printing widths for the first and second time;

[0140] S7: Calculate the longitudinal deformation of the left and right plate diameters of the (N-1)th color according to formulas (19) and (20):

[0141] ΔS (n-1)l = S (n-1)l -S P(n-1) mm (19)

[0142] ΔS (n-1)r = S (n-1)r -S P(n-1) mm (20);

[0143] S P(n-1) =πd+(n-1) Δd mm ; (18)

[0144] d is the nominal diameter of the printing plate, mm;

[0145] Δd is the incremental increase in the plate diameter of the (N-1)th color, in mm;

[0146] n∈[2,m], m is the number of printing color groups;

[0147] S8: Calculate the equivalent longitudinal deformation of the left and right color scale lengths of the Nth color relative to the (N-1)th base color overprint according to formulas (16) and (17):

[0148] zeL e (n-1)l =ΔS (n-1)l *L e / S P(n-1) mm (16)

[0149] zeL e (n-1)r =ΔS (n-1)r *L e / S P(n-1) mm (17);

[0150] Le is the distance of the color mark of the printing plate, set as a constant, and take 20mm;

[0151] S9: Calculate the cumulative longitudinal deformation of the color scale length on the left and right sides of the Nth color of the base color overprint according to formulas (7) and (8):

[0152]

[0153] S10: Calculate the lateral deformation ζC of the left and right color mark spacing of the Nth color in the base color overprinting according to formula (9) n1 :

[0154] ζC n1 =δC nl -δC nr mm (9);

[0155] S11: Calculate the vertical adjustment amount R of the primary color overprint of the Nth color according to formulas (1) and (2): Vn And sequential overprint lateral adjustment amount R Cn , calculated using the following formula:

[0156] R Vn1 =0.5*[ΔF nl +ΔF nr ]-0.5*[∑ζL e(n-1)1l +∑ζL e(n-1)1r ]mm(1)

[0157] R Cn1 =δC nl-0.5*ζC n1 mm(2);

[0158] When R Vn1 When the calculated value is positive, the Nth color group motor accelerates relative to the 1st color group motor, and when it is negative, it decelerates.

[0159] When R Cn1 When the calculated value is positive, the Nth color group color plate moves to the left relative to the 1st color group color plate, and when it is negative, it moves to the right.

Claims

1. A method for compensating primary color overprinting based on deformation of a printing material, characterized in that: A compensating overprinting method for a web-based printing press having multiple color groups comprises the following steps: 1) Set the overprint color mark and color mark detection probe of the color separation printing plate: A left and right overprint color mark is set outside the two sides of the image and text of the 1st to Mth color separation printing plates to be overprinted, respectively. The center line of the overprint color marks on the left and right sides of each color separation printing plate is symmetrical to the longitudinal center line of the printing plate. The longitudinal distances of the overprint color marks of different color separation printing plates are the same and equal to the set plate overprint color mark distance; a group of two color mark detection probes is set behind each color separation printing plate to detect the overprint color marks on the left and right sides of the printing material respectively, and an encoder that can be linked with the color mark detection probe for output is set on the driving motor of each color separation printing plate; 2) Detect and calculate the position and mutual distance of the overprint color marks on both sides of the printing material: In the multi-color overprinting process, the color mark detection probe is used to detect the color separation plates of the 1st to Mth colors, and the repeated overprint color marks including the left and right sides of the 1st to Mth colors are printed on both sides of the printing material. The encoder corresponding to the color separation plate driving motor is used to record the time when the color mark is in place and leaves, and the built-in program is input to calculate the following parameters: 2.1) Detect the width of the left and right overprint color marks of the color group and the first color group of the color separation printing plate where the color mark detection probe is located within the same plate diameter printing width on the printing material, and mark the longitudinal detection height of the left and right overprint color marks of the base color overprint of the color; 2.2) Detect the respective longitudinal distances between the color group of the color separation printing plate where the color mark detection probe is located and the left and right overprint color marks of the first color group within the same plate diameter printing width on the printing material, and mark it as the longitudinal detection distance between the left and right color marks of the base color overprint of the color; 2.3) Detect the longitudinal distance between the overprint color marks of the color separation printing plates where the color mark detection probes of each group of color marks on the printing material are located within two adjacent plate diameter printing widths, and mark them as the plate length detection length on the left and right sides of the color. 3) Calculate the vertical and horizontal overprint deviation between color groups: 3.1) Subtract the left and right longitudinal detection distances between the color marks of the primary color overprints of the second to the Mth colors from the multiples of the plate overprint color mark length, and the difference is the left and right longitudinal overprint deviation of the color relative to the reference printing color group, and the multiple is the difference between the color ranking and the first color, and it is marked as the left and right longitudinal overprint deviation of the primary color overprint of the color; 3.2) Subtract the longitudinal detection heights of the two overprint color marks on the left side of each color, and multiply the difference by the conversion coefficient to obtain the horizontal overprint deviation on the left side; subtract the longitudinal detection heights of the two overprint color marks on the right side of each color, and multiply the difference by the conversion coefficient to obtain the horizontal overprint deviation on the right side, and mark the two horizontal overprint deviations as the left and right horizontal overprint deviations of the base color overprint of the color respectively; the conversion coefficient is related to the pattern of the overprint color mark; 4) Calculate the longitudinal and lateral deformation of the printing material between color groups: 4.1) Subtract the plate length detection length on the left and right sides of a certain color from the plate diameter circumference of the color printing plate to obtain the longitudinal deformation of the plate diameter circumference of the printing material on the printing material between the current color group and the next color group, multiply the difference by the ratio of the plate overprinting color scale length to the plate diameter circumference of the color printing plate, and the value is the equivalent longitudinal deformation of the color scale length on the left and right sides of the next color of the color, add the equivalent longitudinal deformation of the color scale length on the left and right sides of all the color separation plates before the certain color, and mark it as the cumulative color scale length longitudinal deformation on the left and right sides of the base color overprint of the color; 4.2) Subtract the lateral overprint deviations of the left and right color marks of a certain color base color overprint to obtain the lateral deformation of the left and right overprint color mark spacing between the true color group and the first color group of the printing material, and mark it as the lateral deformation of the left and right color mark spacing of the color base color overprint; 5) Calculate the vertical and horizontal overprint adjustment of the color group: 5.1) Subtract the average value of the longitudinal deformation of the left and right color scales of the base color overprint of the original color from the average value of the longitudinal overprint deviation of the left and right sides of the base color overprint of a certain color, and the result is the longitudinal adjustment value of the base color overprint of the color; 5.2) Subtract half of the lateral deformation of the left and right color mark spacing of the primary color overprint from the overprint deviation on the left side of the primary color overprint of the Nth (2≤M) color, and the result is the lateral adjustment value of the primary color overprint of the Nth color; 6) The longitudinal adjustment value of the primary color overprinting from the second to the Mth color and the lateral adjustment value of the primary color overprinting are input into the overprinting control program as feedback values ​​to control the rotation speed of the transmission motor of each color separation printing plate and adjust the relative position of each color separation printing plate.

2. The method for compensating primary color overprinting based on deformation of printing material according to claim 1, characterized in that: When the primary color overprinting mode is adopted, the longitudinal adjustment amount R of the primary color overprinting of the first color unit by the Nth color unit Vn1 And the horizontal adjustment amount R of the base color overprint Cn1 The calculation formula is as follows: R Vn1 =0.5*[ΔF nl +ΔF nr ]-0.5*[∑ζL e(n-1)1l +∑ζL e(n-1)1r ] mm (1) R Cn1 =δC nl -0.5*ζC n1 mm (2) When R Vn1 When the calculated value is positive, the Nth color group motor accelerates relative to the 1st color group motor, and when it is negative, it decelerates. When R Cn1 When the calculated value is positive, the color plate of the Nth color group moves to the left relative to the color plate of the 1st color group, and when it is negative, it moves to the right; ΔF nl and ΔF nr The left and right longitudinal overprint deviations of the base color overprint of the Nth color; δC nl and δC nr The left and right lateral overprint deviations of the base color overprint of the Nth color; ∑ζL e(n-1)1l and ∑ζL e(n-1)1r It is the cumulative longitudinal deformation of the color scale length on the left and right sides of the primary color overprint of the (N-1)th color; ζC n1 It is the lateral deformation of the distance between the left and right color labels of the Nth color.

3. The method for compensating primary color overprinting based on deformation of printing material according to claim 2, characterized in that: ΔF nl =F nl -(n-1)*L e mm (3) ΔF nr =F nr -(n-1)*L e mm (4) δC nl =[h nl -h 1l ]*I mm (5) δC nr =[h nr -h 1r ]*I mm (6) ζC n1 =δC nl -δC nr mm (9) F nl and F nr The vertical detection distance between the color marks of the primary color overprints on the left and right sides of the Nth color; h nl 、h nr 、h 1l and h 1r The vertical detection heights of the overprint color marks on the left and right sides of the base color overprint of the Nth color respectively; zeL e(n-1)l and ζL e(n-1)r It is the equivalent longitudinal deformation of the left and right color scale lengths of the primary color overprint of the (N-1)th color to the Nth color; Le is the distance of the color mark of the printing plate, set as a constant, and take 20mm; I is the conversion factor between the center height and width of the bidirectional overprint color mark. For the wedge-shaped mark, I=W / (H B -H T );W is the length of the wedge mark, H B and H T Mark the heights of the upper and lower bases of the wedge respectively.

4. The method for compensating primary color overprinting based on deformation of printing material according to claim 3, characterized in that: F nl =V n *[t nn1l -t n11l ] mm (10) F nr =V n *[t nnlr -t n11r ] mm (11) h 1l =V n *[t n12l -t n11l ] mm (12) h 1r =V n *[t n12r -t n11r ] mm (13) h nl =V n *[t nn2l -t nn1l ] mm (14) h nr =V n *[t nn2r -t nn1r ] mm (15) ζL e(n-1)l =ΔS (n-1)l *L e / S P(n-1) mm (16) ζL e(n-1)r =ΔS (n-1)r *L e / S P(n-1) mm (17) ΔS (n-1)l and ΔS (n-1)r are the longitudinal deformation of the plate diameter circumference on the left and right sides of the (N-1)th color respectively; S P(n-1) It is the circumference of the printing plate of the (N-1)th color.

5. The method for compensating primary color overprinting based on deformation of printing material according to claim 4, characterized in that: S P(n-1) =πd+(n-1)*Δd mm (18) ΔS (n-1)l =S (n-1)l -S P(n-1) mm (19) ΔS (n-1)r =S (n-1)r -S P(n-1) mm (20) S (n-1)l and S (n-1)r The length of the left and right sides of the plate length for the (N-1)th color of the base color overprint. d is the nominal diameter of the printing plate, in mm; Δd is the incremental increase in the plate diameter of the (N-1)th color, in mm; n∈[2,m], m is the number of printing color groups.

6. The method for compensating primary color overprinting based on deformation of printing material according to claim 5, characterized in that: S (n-1)l =V (n-1) *{[Nt (n-1)(n-1)1l ]-t (n-1)(n-1)1l } mm (21) S (n-1)r =V (n-1) *{[Nt (n-1)(n-1)1r ]-t (n-1)(n-1)1r } mm (22) V n and V (n-1) It is the color separation plate speed value when the color mark of the Nth and (N-1th) colors are detected.

7. The method for compensating primary color overprinting based on deformation of printing material according to claim 6, characterized in that: V n =1.5708d n *[t znn2l -t znn1l ] mm / s (23) V (n-1) =1.5708d (n-1) *[t z(n-1)(n-1)2l -t z(n-1)(n-1)1l ] mm / s (24) t n(n-1)1l It is the time value when the left color mark detection probe of the Nth color reads the color mark of the (N-1)th color group entering; t n(n-1)2r The time value when the color mark detection probe on the right side of the Nth color reads the color mark of the (N-1)th color group leaves; [Nt (n-1)(n-1)1r ] is the time value when the right color mark detection probe of the (N-1)th color reads the color mark of the (N-1)th color group for the second time; The meanings of the other time symbols are similar. t znn2l The Z pulse moment of the encoder when the color mark detection probe on the left side of the Nth color reads the end of N color marks; t znn1l The Z pulse moment of the encoder when the vehicle probe reads the color mark on the left side of the Nth color to the beginning of the Nth color mark.

8. The method for compensating primary color overprinting based on deformation of printing material according to claim 1, characterized in that: The printing press is equipped with a total of M color groups, each of which includes a color separation plate, a color separation plate drive motor, an encoder, a color mark detection probe, a high-frequency counter and an operation controller. The high-frequency counter reads the output signals of the color mark detection probe and the encoder and records the signal reading time through a pulse signal. The operation controller collects signals, calculates and analyzes the longitudinal and lateral overprint deviations of each two colors through a control program and issues adjustment instructions.

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