Compensation sequence overprinting method based on printing material deformation

Abstract

The invention discloses a compensation sequence overprinting method based on printing material deformation. The compensation sequence overprinting method for a roll-shaped base material printing machine with a plurality of color groups comprises the following steps of: arranging an overprinting color code and a color code detection probe of a color separation printing plate; 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 a printing press overprinting technology, in particular to a compensation sequence overprinting method based on the deformation amount of a printing material. Background Art

[0002] When a multi-color web-fed gravure printing machine is overprinting colors, the usual practice is to set a printing overprint color mark in the vacant area outside one side of the printed image, set a color mark detection probe behind the color separation printing plates of the second color to the last color of the printing machine, set an encoder on the color separation printing plate drive motor, read the number of pulses detected by each color mark probe when the original color overprint color mark and the previous color overprint color mark arrive and leave, calculate the difference between the two pulses at the corresponding position, and obtain the overprint difference between the color where the probe is located and the previous color, and convert the overprint deviation value into an adjustment value to perform registration compensation on the color separation printing plate drive motor. Thereby reducing the overprint deviation and improving the overprint quality. 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 amount. 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 compensating sequential overprinting method based on the deformation amount 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 sequential overprinting method based on the deformation amount of the printing material, the compensating sequential 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] Set overprint color marks on the left and right sides of the images and texts of the 1st to Mth color separation printing plates to be overprinted, respectively; the center lines of the overprint color marks on the left and right sides of each color separation printing plate are 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 overprint color mark distance of the printing plate; set a group of two color mark detection probes behind each color separation printing plate to detect the overprint color marks on the left and right sides of the printing material respectively; set an encoder with a linkage output with the color mark detection probe on the driving motor of each color separation printing plate;

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

[0008] In the multi-color overprint process, the color mark detection probe is used to detect that the 1st to Mth color separation printing plates are printed on both sides of the printing material respectively, and the repeated overprint color marks including the 1st to Mth colors on the left and right sides are printed one by one. The encoder of the printing plate drive 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 respective longitudinal widths of the left and right overprint color marks of the color group of the color separation printing plate where the color mark detection probe is located and the previous color group within the same plate diameter printing width on the printing material, and mark it as the longitudinal detection height of the left and right overprint color marks of the sequential 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 overprint color mark of the previous color group within the same plate diameter printing width on the printing material, and mark it as the longitudinal detection distance between the overprint color marks on the left and right sides of the sequential 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 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;

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

[0013] 3.1) Subtract the longitudinal detection distance between the left and right overprint color marks of the 2nd to Mth color sequential overprint from the plate overprint color mark distance, and the difference is the longitudinal overprint deviation of the left and right sides of the color group relative to the previous color group, and it is marked as the longitudinal overprint deviation of the left and right sides of the sequential overprint of the color;

[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 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 left and right horizontal overprint deviations as the left and right horizontal overprint deviations of the sequential overprint of the color, respectively, and the conversion coefficient is related to the pattern of the overprint color mark;

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

[0016] 4.1) Subtract the left and right plate length detection lengths 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, and multiply the difference by the ratio of the plate overprinting color scale length to the plate diameter circumference of the color printing plate. This value is the equivalent longitudinal deformation of the left and right color scale lengths of the color to the next color, and is marked as the equivalent longitudinal deformation of the left and right color scale lengths of the sequential overprinting of the color;

[0017] 4.2) Subtract the lateral overprint deviations of the left and right color codes of a certain color from each other to obtain the lateral deformation of the left and right overprint color code spacing between the current color group and the previous color group of the printing material, and mark it as the lateral deformation of the left and right color code spacing of the color sequential overprinting.

[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 scale lengths of the previous color from the average value of the longitudinal deviation of the left and right color scales of the sequential overprint of a certain color from the average value of the longitudinal deviation of the left and right color scales of the sequential overprint of the previous color. The result is the longitudinal adjustment value of the sequential overprint of the color.

[0020] 5.2) Subtract half of the lateral deformation of the left and right color mark spacing from the lateral overprint deviation on the left side of the sequential overprint of a certain color, and the result is the lateral adjustment value of the sequential overprint of the color;

[0021] 6) The longitudinal adjustment value of the sequential overprinting from the 2nd to the Mth color and the lateral adjustment value of the sequential overprinting are input as feedback values ​​into the overprinting control program to control the rotation speed of the drive motor of each color separation printing plate and adjust the relative position of each color separation printing plate.

[0022] As an improvement, the printing press is provided with a total of M color groups, each color group includes a color separation printing plate, a color separation printing 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 reading signal 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.

[0023] As an improvement, the Nth color group sequential overprinting longitudinal adjustment amount R Vn And sequential overprint lateral adjustment amount R Cn The calculation formula is as follows:

[0024] R Vn =0.5[ΔL nl +ΔL nr ]-0.5*[ζL e(n-1)l +ζL e(n-1)r ]mm(1)

[0025] R Cn =ΔC nl -0.5*ζC n mm(2)

[0026] When R Vn When the calculated value is positive, the Nth color group driving motor accelerates relative to the (N-1)th color group driving motor, and when it is negative, it decelerates.

[0027] When R Cn When the calculated value is positive, the Nth color separation plate moves to the left, and when it is negative, it moves to the right;

[0028] ΔL nl and ΔL nr The left and right longitudinal overprint deviations of the sequential overprint of the Nth color;

[0029] ΔC nl and ΔC nr The left and right lateral overprint deviations of the sequential overprint of the Nth color;

[0030] zeL e(n-1)l and ζL e(n-1)r is the equivalent longitudinal deformation of the left and right color scale lengths of the sequential overprinting of the (N-1)th color;

[0031] ζC n It is the lateral deformation of the distance between the left and right color labels of the Nth color.

[0032] As an improvement, the calculation formula is as follows:

[0033] ΔL nl =L nl -L e mm (3)

[0034] ΔL nr =L nr -L e mm (4)

[0035] ΔC nl =[H nl -H (n-1)l ]*I mm (5)

[0036] ΔC nr =[H nr -H (n-1)r ]*I mm (6)

[0037] zeL e (n-1)l =ΔS (n-1)l *L e / S P(n-1) mm (7)

[0038] zeL e (n-1)r =ΔS (n-1)r *L e / S P(n-1) mm (8)

[0039] ζC n =ΔC nl -ΔC nrmm (9)

[0040] L nl and L nr are the longitudinal detection distances between the left and right overprint color marks of the sequential overprint of the Nth color;

[0041] H nl , H nr , H (n-1)l and H (n-1)r The vertical detection heights of the overprint color marks on the left and right sides of the sequential overprint of the Nth color respectively;

[0042] ΔS (n-1)l and ΔS (n-1)r is the longitudinal deformation of the left and right plate diameters of the (N-1)th color; I is the conversion coefficient between the center height and width of the bidirectional overprinting color mark. For the wedge mark, I = W / (H B -H T );W is the length of the wedge mark, H B and H T are the heights of the upper and lower bases of the wedge mark respectively;

[0043] L e For the plate overprint color mark distance, set a constant value of 20mm;

[0044] S P(n-1) is the circumference of the printing plate of the (N-1)th color;

[0045] As an improvement, the calculation formula is as follows:

[0046] S P(n-1) =πd+(n-1) *Δd mm ; (10)

[0047] L nl =V n *[t nn1l -t n(n-1)1l ] mm (11)

[0048] L nlr =V n *[t nn1r -t n(n-1)1r ] mm (12)

[0049] H (n-1)l = V n *[t n(n-1)2l -t n(n-1)1l ] mm (13)

[0050] H (n-1)r = V n *[t n(n-1)2r -t n(n-1)1r ] mm (14)

[0051] H nl = V n *[t nn2l -t nn1l ] mm (15)

[0052] H nr = V n *[t nn2r -t nn1r ] mm (16)

[0053] ΔS (n-1)l = S (n-1)l -S P(n-1) mm (17)

[0054] ΔS (n-1)r = S (n-1)r -S P(n-1) mm (18)

[0055] S (n-1)l and S (n-1)r The length of the left and right plates of the (N-1)th color;

[0056] V n It is the linear speed value of the color separation plate when the color mark of the Nth color is detected.

[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, the calculation formula is as follows:

[0061] S (n-1)l = V (n-1) *{[Nt (n-1) (n-1)1l ]-t (n-1) (n-1)1l mm (19)

[0062] S (n-1)r = V (n-1) *{[Nt (n-1) (n-1)1r ]-t (n-1) (n-1)1r mm (20)

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

[0064] As an improvement, the calculation formula is as follows:

[0065] V n =1.5708d n *[t znn2l -t znn 1l ] mm / s (21)

[0066] V (n-1) =1.5708d (n-1) *[t z(n-1) (n-1)2l -t z(n-1) (n-1)1l ] mm / s (22)

[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 left color mark detection probe of the Nth color reads the end of the color marks of the N color groups;

[0072] t znn1l The Z pulse time of the encoder when the left color mark detection probe of the Nth color reads the beginning of the color mark of the N color groups.

[0073] Compared with the prior art, the present invention has the following beneficial effects:

[0074] 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

[0075] Figure 1 This is a schematic diagram of sequential overprinting color mark setting and calculation.

[0076] Figure 2 Schematic diagram of color scale setting and calculation for longitudinal deformation error detection.

[0077] Figure 3 Schematic diagram of a multi-color printing press. DETAILED DESCRIPTION

[0078] The present invention will be further described below in conjunction with the accompanying drawings.

[0079] A compensating sequential 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 of which 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.

[0080] Figure 1 The schematic diagram of sequential overprinting color mark setting and calculation principle shows that 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, they are put into 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 ), (t211r , 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 12 and the right color mark 22 are read by the third color group probe to enter and leave is (t 321l , t 322l ), (t 321r , t 322r ), 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 14 and the right color mark 24 are read by the Nth color group probe to enter and leave is [t n(n-1)1l , t n(n-1)2l ],[t n(n-1)1r , t n(n-1)2r ], 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 );

[0081] Figure 2Schematic 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.

[0082] like Figure 2 , 3 As shown, the compensation sequential overprinting method based on the deformation amount of the printing material includes the following steps:

[0083] 1) Set the overprint color mark and color mark detection probe of the color separation printing plate:

[0084] Overprint color marks 11 to (10+M) and 21 to (20+M) are respectively arranged on the left and right sides of the images and texts of the 1st to Mth color separation printing plates 1 to be overprinted, the center lines of the overprint color marks on the left and right sides of each color separation printing plate are 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 an encoder 2 and a high-speed counter 4 are arranged on the driving motor of each color separation printing plate to output in linkage with the color mark detection probe;

[0085] 2) Detect and calculate the position and mutual distance of the overprinted color marks on both sides of the printing material:

[0086] In the multi-color overprinting process, the color mark detection probe is used to detect that the 1st to Mth color separation printing plates print repeated overprint color marks including the 1st to Mth colors on the left and right sides on both sides of the printing material 7, and the encoder and high-speed counter of the printing plate driving motor are used to record the time when the color mark enters and leaves, and the built-in program is input to calculate the following parameters:

[0087] 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 previous color group within the same plate diameter printing width on the printing material 7, 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 marked as the longitudinal detection height of the overprint color mark on the left and right sides of the sequential overprint of the color;

[0088] 2.2) Detect the time difference between the color group of the color separation plate where the detection probe is located and the overprint color mark of the previous color group in the same plate diameter printing width on the printing material, and multiply it by the motor speed value to obtain the longitudinal distance L between the adjacent color marks on the left and right sides. nl , L nr , and marked as the longitudinal detection distance between the left and right overprint color marks of the sequential overprint of the color;

[0089] 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 left and right plate length detection length of the color;

[0090] 3) Calculate the vertical and horizontal overprint deviation between color groups:

[0091] 3.2) Subtract the longitudinal detection distance between the left and right overprint color marks of the 2nd to Mth color sequence from the overprint color mark length of the printing plate, and the difference is the longitudinal overprint deviation ΔL of the left and right sides of the color group relative to the previous color group. nl , ΔL nr , and marked as the left and right longitudinal overprint deviations of the sequential overprint of the color;

[0092] 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 obtain the horizontal overprint deviation ΔC on the left side. nl ; Subtract the vertical detection heights of the two front and rear overprint color marks on the right side of each color, and multiply the difference by the conversion coefficient to obtain the horizontal overprint deviation ΔC on the right side. nr, marking the left and right horizontal overprint deviations as the left and right horizontal overprint deviations of the sequential overprint of the color respectively;

[0093] 4) Calculate the longitudinal and lateral deformation of the printing material between color groups:

[0094] 4.1) Subtract the left and right plate length detection lengths of a certain 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 , multiply the difference by the ratio of the overprint color scale length to the circumference of the color plate diameter, and the value is the equivalent longitudinal deformation of the left and right color scale lengths of the next color ζL e(n-1)l , ζL e(n-1)r , marked as the equivalent longitudinal deformation of the left and right color scale lengths of the sequential overprinting of the color;

[0095] 4.2) Subtract the lateral overprint deviation of the left and right color marks of a certain color from each other to obtain the lateral deformation ζC of the spacing between the left and right overprint color marks of the printing material between the original color group and the previous color group. n , and marked as the lateral deformation of the left and right color mark spacing of the color sequence overprinting.

[0096] 5) Calculate the vertical and horizontal overprint adjustment of the color group:

[0097] 5.1) Subtract the average value of the longitudinal deformation of the left and right color scales of the sequential overprint of the original color from the average value of the longitudinal overprint deviation of the left and right sides of the sequential overprint of a certain color, and the result is the longitudinal adjustment value R of the sequential overprint of the color. Vn ;

[0098] 5.2) Subtract half of the lateral deformation of the left and right color mark spacing from the lateral overprint deviation of the left side of the sequential overprint of a certain color. The result is the lateral adjustment value R of the sequential overprint of the color. Cn ;

[0099] 6) The longitudinal adjustment value of the sequential overprinting from the 2nd to the Mth color and the lateral adjustment value of the sequential overprinting are input as feedback values ​​into the overprinting control program to control the rotation speed of the drive motor of each color separation printing plate and adjust the relative position of each color separation printing plate.

[0100] Sequential overprint calculation process based on the deformation of the printing material:

[0101] S1: Calculate the V according to formulas (21) and (22) n and V (n-1) The speed value of the plate roller of a color separation plate during color mark detection:

[0102] V n =1.5708d n*[t znn2l -t znn 1l ] mm / s (21)

[0103] V (n-1) =1.5708d (n-1) *[t z(n-1) (n-1)2l -t z(n-1) (n-1)1l ] mm / s (22);

[0104] 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;

[0105] 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;

[0106] [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;

[0107] [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;

[0108] d n and d (n-1) is the actual diameter of the Nth and (N-1)th color separation printing plates.

[0109] d n =d+(n-1)Δd

[0110] d is the nominal diameter of the printing plate, in mm;

[0111] Δd is the incremental increase in the plate diameter of the (N-1)th color, in mm;

[0112] n∈[2,m], m is the number of printing color groups;

[0113] S2: Calculate the longitudinal detection distance between the left and right overprint color marks of the Nth color sequential overprint according to formulas (11) and (12):

[0114] L nl =V n *[t nn1l -t n(n-1)1l ] mm (11)

[0115] L nr =V n *[t nn1r -t n(n-1)1r] mm (12);

[0116] 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;

[0117] [t n(n-1)1l ] and [t n(n-1)1r ] is the time when the left and right overprint color marks of the (N-1)th color group are detected by the color mark probe of the (N-1)th color group;

[0118] S3: Calculate the vertical detection height of the left and right overprint color marks of the sequential overprint of the Nth color according to formulas (13), (14), (15) and (16):

[0119] H (n-1)l = V n *[t n(n-1)2l -t n(n-1)1l ] mm (13)

[0120] H (n-1)r = V n *[t n(n-1)2r -t n(n-1)1r ] mm (14)

[0121] H nl = V n *[t nn2l -t nn1l ] mm (15)

[0122] H nr =V n *[t nn2r -t nn1r ]mm(16);

[0123] [t n(n-1)2l ] and [t n(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 Nth color group leaves and enters;

[0124] [t n(n-1)2r ] and [t n(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 Nth color group leaves and enters;

[0125] 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;

[0126] t nn2r and nn1rThe 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;

[0127] S4: Calculate the left and right longitudinal overprint deviations of the sequential overprint of the Nth color according to formulas (3) and (4):

[0128] ΔL nl =L nl -L e mm (3)

[0129] ΔL nr =L nr -L e mm (4);

[0130] S5: Calculate the left and right lateral overprint deviations of the sequential overprint of the Nth color according to formulas (5) and (6):

[0131] ΔC nl =[H nl -H (n-1)l ]*I mm (5)

[0132] ΔC nr =[H nr -H (n-1)r ]*I mm (6);

[0133] 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;

[0134] S6: Calculate the left and right plate length detection lengths of the (N-1)th color according to formulas (19) and (20):

[0135] S (n-1)l = V (n-1) *{[Nt (n-1) (n-1)1l ]-t (n-1) (n-1)1l mm (19)

[0136] S (n-1)r = V (n-1) *{[Nt (n-1) (n-1)1r ]-t (n-1) (n-1)1r} mm (20);

[0137] [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;

[0138] [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;

[0139] S7: Calculate the longitudinal deformation of the left and right plate diameters of the (N-1)th color according to formulas (17) and (18):

[0140] ΔS (n-1)l = S (n-1)l -S P(n-1) mm (17)

[0141] ΔS (n-1)r = S (n-1)r -S P(n-1) mm (18);

[0142] S P(n-1) is the circumference of the printing plate of the (N-1)th color, calculated according to formula (10):

[0143] S P(n-1) =πd+(n-1) * Δd mm (10);

[0144] S8: Calculate the equivalent longitudinal deformation of the left and right color scale lengths of the Nth color sequential overprinting according to formulas (7) and (8):

[0145] zeL e (n-1)l =ΔS (n-1)l *L e / S P(n-1) mm (7)

[0146] zeL e (n-1)r =ΔS (n-1)r *L e / S P(n-1) mm (8);

[0147] L e For the plate overprint color mark distance, set a constant, generally 20mm;

[0148] S9: Calculate the lateral deformation of the distance between the left and right color marks of the Nth color according to formula (9) ζC n :

[0149] ζCn =ΔC nl -ΔC nr mm (9);

[0150] S10: Calculate the longitudinal adjustment amount R of the sequential overprinting of the Nth color according to formulas (1) and (2) Vn And sequential overprint lateral adjustment amount R Cn :

[0151] R Vn =0.5*[ΔL nl +ΔL nr ]-0.5*[ζL e(n-1)l +ζL e(n-1)r ]mm(1)

[0152] R Cn =ΔC nl -0.5*ζC n mm(2).

Claims

1. A compensating sequential overprinting method based on deformation of a printing material, characterized in that: A method for compensating sequential overprinting 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: Set overprint color marks on the left and right sides of the images and texts of the 1st to Mth color separation printing plates to be overprinted, respectively; the center lines of the overprint color marks on the left and right sides of each color separation printing plate are 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 overprint color mark distance of the printing plate; set a group of two color mark detection probes behind each color separation printing plate to detect the overprint color marks on the left and right sides of the printing material respectively; set an encoder with a linkage output with the color mark detection probe on the driving motor of each color separation printing plate; 2) Detect and calculate the position and mutual distance of the overprinted color marks on both sides of the printing material: In the multi-color overprint process, the color mark detection probe is used to detect that the 1st to Mth color separation printing plates are printed on both sides of the printing material respectively, and the repeated overprint color marks including the 1st to Mth colors on the left and right sides are printed one by one. The encoder of the printing plate drive 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 respective longitudinal widths of the left and right overprint color marks of the color group of the color separation printing plate where the color mark detection probe is located and the previous color group within the same plate diameter printing width on the printing material, and mark it as the longitudinal detection height of the left and right overprint color marks of the sequential 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 overprint color mark of the previous color group within the same plate diameter printing width on the printing material, and mark it as the longitudinal detection distance between the overprint color marks on the left and right sides of the sequential 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 longitudinal detection distance between the left and right overprint color marks of the 2nd to Mth color sequential overprint from the plate overprint color mark distance, and the difference is the longitudinal overprint deviation of the left and right sides of the color group relative to the previous color group, and it is marked as the longitudinal overprint deviation of the left and right sides of the sequential 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 left and right horizontal overprint deviations as the left and right horizontal overprint deviations of the sequential overprint of the color, respectively, and 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 left and right plate length detection lengths 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, and multiply the difference by the ratio of the plate overprinting color scale length to the plate diameter circumference of the color printing plate. This value is the equivalent longitudinal deformation of the left and right color scale lengths of the color to the next color, and is marked as the equivalent longitudinal deformation of the left and right color scale lengths of the sequential overprinting of the color; 4.2) Subtract the lateral overprint deviations of the left and right color codes of a certain color from each other to obtain the lateral deformation of the left and right overprint color code spacing between the current color group and the previous color group of the printing material, and mark it as the lateral deformation of the left and right color code spacing of the color sequential overprinting. 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 scale lengths of the previous color from the average value of the longitudinal deviation of the left and right color scales of the sequential overprint of a certain color from the average value of the longitudinal deviation of the left and right color scales of the sequential overprint of the previous color. The result is the longitudinal adjustment value of the sequential overprint of the color. 5.2) Subtract half of the lateral deformation of the left and right color mark spacing from the lateral overprint deviation on the left side of the sequential overprint of a certain color, and the result is the lateral adjustment value of the sequential overprint of the color; 6) The longitudinal adjustment value of the sequential overprinting from the 2nd to the Mth color and the lateral adjustment value of the sequential overprinting are input as feedback values ​​into the overprinting control program to control the rotation speed of the drive motor of each color separation printing plate and adjust the relative position of each color separation printing plate.

2. A method for compensating sequential overprinting based on deformation of a 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.

3. The method for compensating sequential overprinting based on deformation of printing materials according to claim 1, characterized in that: The Nth color group sequential overprinting longitudinal adjustment amount R Vn And sequential overprint lateral adjustment amount R Cn The calculation formula is as follows: R Vn =0.5[ΔL nl +ΔL nr ]-0.5*[ζL e(n-1)l +ζL e(n-1)r ]mm (1) R Cn =ΔC nl -0.5*ζC n mm (2) When R Vn When the calculated value is positive, the Nth color group driving motor accelerates relative to the (N-1)th color group driving motor, and when it is negative, it decelerates. When R Cn When the calculated value is positive, the Nth color separation plate moves to the left, and when it is negative, it moves to the right; ΔL nl and ΔL nr The left and right longitudinal overprint deviations of the sequential overprint of the Nth color; ΔC nl and ΔC nr The left and right lateral overprint deviations of the sequential overprint of the Nth color; zeL e(n-1)l and ζL e(n-1)r is the equivalent longitudinal deformation of the left and right color scale lengths of the sequential overprinting of the (N-1)th color; ζC n It is the lateral deformation of the distance between the left and right color labels of the Nth color.

4. The method for compensating sequential overprinting based on deformation of printing material according to claim 3, characterized in that: ΔL nl =L nl -L e mm (3) ΔL nr =L nr -L e mm (4) ΔC nl =[H nl -H (n-1)l ]*Imm (5) ΔC nr =[H nr -H (n-1)r ]*Imm (6) ζL e(n-1)l =ΔS (n-1)l *L e / S P(n-1) mm (7) ζL e(n-1)r =ΔS (n-1)r *L e / S P(n-1) mm (8) ζC n =ΔC nl -ΔC nr mm (9) L nl and L nr The vertical detection distance between the left and right overprint color marks of the sequential overprint of the Nth color; H nl , H nr , H (n-1)l and H (n-1)r The vertical detection heights of the overprint color marks on the left and right sides of the sequential overprint of the Nth color respectively; ΔS (n-1)l and ΔS (n-1)r is the longitudinal deformation of the left and right plate diameters of the (N-1)th color; I is the conversion factor between the center height and width of the bidirectional overprinting color mark. For the wedge mark, I = W / (H B -H T );W is the length of the wedge mark, H B and H T L are the heights of the upper and lower bases of the wedge mark respectively; e For the plate overprint color mark distance, set a constant value of 20mm; S P(n-1) It is the circumference of the printing plate of the (N-1)th color.

5. The method for compensating sequential overprinting based on deformation of printing materials according to claim 4, characterized in that: S P(n-1) =πd+(n-1)*Δdmm (10) L nl =V n *[t nn1l -t n(n-1)1l ]mm (11) L nlr =V n *[t nn1r -t n(n-1)1r ]mm (12) H (n-1)l =V n *[t n(n-1)2l -t n(n-1)1l ]mm (13) H (n-1)r =V n *[t n(n-1)2r -t n(n-1)1r ]mm (14) H nl =V n *[t nn2l -t nn1l ]mm (15) H nr =V n *[t nn2r -t nn1r ]mm (16) ΔS (n-1)l =S (n-1)l -S P(n-1) mm (17) ΔS (n-1)r =S (n-1)r -S P(n-1) mm (18) S (n-1)l and S (n-1)r The length of the left and right plates of the (N-1)th color; V n It is the linear speed value of the color separation printing plate when the color mark of the Nth color is detected. 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 sequential 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 (19) S (n-1)r =V (n-1) *{[Nt (n-1)(n-1)1r ]-t (n-1)(n-1)1r }mm (20) V (n-1) It is the linear speed value of the color separation printing plate when the color mark of the (N-1)th color is detected.

7. The method for compensating sequential 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 (21) V (n-1) =1.5708d (n-1) *[t z(n-1)(n-1)2l -t z(n-1)(n-1)1l ]mm / s (22) 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 left color mark detection probe of the Nth color reads the end of N color marks; t znn1l It is 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.

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