PVC card green printing process based on water-based ink

Abstract

The invention belongs to the technical field of printing, and provides a PVC card green printing process based on water-based ink, which comprises the following steps: integrating and merging adjacent printing sub-regions in the vertical direction of a printing path to obtain merged sub-regions, and analyzing whether only flat sub-regions or non-flat sub-regions exist in the merged sub-regions or not; if only the flat sub-region exists, ink roller height adjustment does not need to be carried out on the combined sub-region, if only the non-flat sub-region exists, a height adjustment coefficient is obtained, the height of an ink roller is adjusted, printing work is carried out, and if the flat region and the non-flat region exist in the combined sub-region, printing is carried out on the flat region during printing. According to the printing method for the PVC printing card with the uneven surface, the non-flat area is printed to complete the printing work, and after the printing work of the combined sub-area on the PVC printing card is completed, the next combined sub-area is printed according to the preset printing path, so that the printing method for the PVC printing card with the uneven surface is provided.

Description

Technical Field

[0001] The invention belongs to the technical field of printing, in particular to a green printing process for PVC cards based on water-based ink. Background Art

[0002] Green printing technology is an inevitable trend of future development. With the improvement of people's environmental awareness and the increasingly stringent environmental regulations, more and more companies are beginning to adopt green printing technology. Generally, green printing uses water-based ink to print on PVC cards through ink rollers. However, due to the uneven surface flatness of PVC cards, it is very easy to cause blurred patterns or texts after printing.

[0003] In the prior art, green printing generally uses water-based ink to print on PVC cards through ink rollers. However, due to the uneven surface flatness of PVC cards, it is very easy to cause blurred patterns or texts after printing during printing. Therefore, before printing on PVC cards, the surface flatness of PVC cards is first analyzed, and the printing sub-areas with uneven surfaces of PVC cards are selected. The height of the ink roller is adjusted during the printing process, which solves the problem of blurred patterns or texts after printing due to the uneven surface flatness of PVC cards.

[0004] To this end, the present invention provides a green printing process for PVC cards based on water-based ink. Summary of the invention

[0005] In order to make up for the deficiencies of the prior art, at least one technical problem raised in the background technology is solved.

[0006] The technical solution adopted by the present invention to solve its technical problem is:

[0007] A green printing process for PVC cards based on water-based ink, comprising:

[0008] Step 1: Process the printed area on the surface of the PVC printed card to obtain several printed sub-areas, obtain the printed sub-area data, wherein the printed sub-area data includes the printed sub-area thickness, process the printed sub-area thickness, output the thickness difference, and compare the thickness difference with the thickness difference range. If the thickness difference is not within the thickness difference range, that is, the thickness exceeds the range, the sub-area with the thickness exceeding the range is marked as a non-flat area;

[0009] Step 2: Analyze the uneven area to obtain convex areas and concave areas, analyze and process the convex areas and concave areas, output the convexity and concave values ​​and convexity and concave degree values, process the convexity and concave values ​​and convexity and concave degree values, output the surface flatness value, and compare the surface flatness value with the surface flatness threshold. If the surface flatness value is greater than the surface flatness threshold, generate a thickness unevenness signal;

[0010] Step 3: Based on the thickness unevenness signal, multiple groups of previous printing data are obtained, wherein the previous printing data include the ink roller height difference value and the previous thickness difference value, the ink roller height value and the previous thickness deviation value are analyzed and processed to obtain a correlation degree value, and compared with the correlation degree threshold value, if the correlation degree value is greater than or equal to the correlation degree threshold value, an adjustment analysis signal is generated;

[0011] Step 4: Based on the adjustment analysis signal, the merged sub-area is obtained, the merged sub-area is analyzed and processed, the height adjustment coefficient is obtained, and the height of the ink roller is adjusted to complete the printing work on the surface of the PCV printing plate.

[0012] As a further solution of the present invention, the method for obtaining the uneven area is:

[0013] Divide the printing area into equal areas to obtain a number of printing sub-areas;

[0014] Obtain the thickness of the printed sub-area, add up the thickness of all printed sub-areas and take the average value to obtain the average thickness of the sub-areas;

[0015] Subtract the thickness of the printed sub-area from the average thickness of the sub-area to obtain the thickness difference;

[0016] The thickness difference is compared with the thickness difference range as follows:

[0017] If the thickness difference is not within the thickness difference range, that is, the thickness exceeds the range, the sub-region with the thickness exceeding the range is marked as a non-flat region.

[0018] As a further solution of the present invention, the convex area and the concave area are obtained by:

[0019] The thickness difference corresponding to the non-flat area is obtained. If the thickness difference corresponding to the non-flat area is positive, the non-flat area with the positive thickness difference is marked as a convex area. If the thickness difference corresponding to the non-flat area is negative, the non-flat area with the negative thickness difference is marked as a concave area.

[0020] As a further solution of the present invention, the surface flatness value is obtained by:

[0021] Substitute the convexity and concavity value G and the convexity and concavity degree value CD into the formula: The surface flatness value P is calculated, where α and β represent weight coefficients, α is 2.1365, and β is 1.6547.

[0022] As a further solution of the present invention, the method for obtaining the convex and concave values ​​is:

[0023] Count the number of convex areas and the number of concave areas to obtain the number of convex-concave areas, and calculate the ratio of the number of convex-concave areas in the printing area to the total number of printed sub-areas in the printing area to obtain a convex-concave value, which is marked as G;

[0024] The convexity and concavity value is obtained as follows:

[0025] Obtain the thickness difference corresponding to the convex area, add and average the thickness difference corresponding to the convex area, and obtain the convex thickness difference;

[0026] Calculate the ratio of the convex thickness difference value to the end point value of the thickness difference range to obtain the convex thickness difference coefficient;

[0027] Obtain the thickness difference corresponding to the concave area, add the thickness difference corresponding to the concave area to obtain the average value, and take the absolute value to obtain the concave thickness difference;

[0028] The concave thickness difference value is calculated by ratio with the end point value of the thickness difference range to obtain the concave thickness difference coefficient;

[0029] The convex thickness difference coefficient and the concave thickness difference coefficient are added together to obtain the convexity and concaveness value, which is marked as CD.

[0030] As a further solution of the present invention, the relevant sub-regions are obtained by:

[0031] Dividing the previous printing plate area into equal areas to obtain a plurality of previous printing sub-areas;

[0032] Obtaining the previous thickness difference value and the ink roller height difference value corresponding to the previous printing sub-area, and extracting the value of the previous thickness difference value and the ink roller height difference value corresponding to the previous printing sub-area;

[0033] The value of the thickness difference corresponding to the previous printing sub-area and the value of the ink roller height difference are randomly extracted, and the positive and negative values ​​are compared. The process is as follows:

[0034] If the value of the previous thickness difference corresponding to the previous printing sub-region and the value of the ink roller height difference have the same positive and negative values, the previous printing sub-regions with the same positive and negative values ​​are marked as related sub-regions.

[0035] As a further solution of the present invention, the method for obtaining the association degree value is:

[0036] Obtaining the number of relevant sub-regions, calculating the ratio of the number of relevant sub-regions to the total number of previously printed sub-regions, and obtaining a relevant number ratio;

[0037] Based on the relevant sub-region, the value of the previous thickness difference of the relevant sub-region is calculated by ratio with the value of the ink roller height difference to obtain the relevant sub-coefficient;

[0038] All the correlation sub-coefficients are subjected to variance calculation to obtain the correlation coefficient;

[0039] The correlation coefficient is calculated by ratio calculation to obtain the correlation degree value.

[0040] As a further solution of the present invention, the height adjustment coefficient is obtained by:

[0041] If there are only uneven areas in the merged sub-area, the ink roller height needs to be adjusted during printing. The process is as follows:

[0042] All relevant sub-coefficients are added and averaged to obtain the height adjustment coefficient, which is marked as K.

[0043] As a further solution of the present invention, the ink roller height adjustment process is as follows:

[0044] Acquire a non-flat region in the merged sub-region, wherein the non-flat region in the merged sub-region includes a convex region and a concave region;

[0045] Count the number of convex and concave regions in the merged sub-regions and compare them. The process is as follows:

[0046] If the number of convex regions in the merged sub-regions is greater than the number of concave regions, then the formula: H t =H d +H d × K, calculate the adjusted ink roller height H t , where H d is the current unadjusted ink roller height;

[0047] If the number of convex regions in the merged sub-region is less than the number of concave regions, then the formula: H t =H d -H d × K, calculate the adjusted ink roller height H t , where H d This is the current unadjusted ink roller height.

[0048] As a further solution of the present invention, if there are flat areas and non-flat areas in the merged sub-area, when printing is performed, printing is first performed according to the printing operation on the flat area, and then the printing operation is completed according to the printing operation on the non-flat area;

[0049] After the printing of the merged sub-areas on the PVC printed card is completed, the next merged sub-area is printed according to the preset printing path.

[0050] The beneficial effects of the present invention are as follows:

[0051] (1) The present invention processes the printed area on the surface of the PVC printed card to obtain several printed sub-areas, obtains the printed sub-area data, and performs analysis and processing to obtain a non-flat area, analyzes the non-flat area to obtain a convex area and a concave area, performs analysis and processing based on the convex area and the concave area, outputs the convex and concave values ​​and the convex and concave degree values, processes the convex and concave values ​​and the convex and concave degree values, and generates a thickness unevenness signal, thereby firstly identifying the non-flat area by analyzing the thickness of the printed sub-area in the PVC printed card area, and further analyzing the non-flat area to distinguish it into a convex area and a concave area, and obtaining the number ratio of the convex area and the concave area in the PVC printed card area, as well as the degree of deviation between the convex area, the concave area and the overall thickness mean of the PVC printed card area, reflecting the flatness of the printed area on the surface of the PVC printed card, and providing data for adjusting the printing parameters of the PVC printed card before printing;

[0052] (2) The present invention obtains multiple sets of previous printing data based on the thickness unevenness signal, wherein the previous printing data includes the ink roller height difference and the thickness difference, analyzes and processes the ink roller height value and the thickness deviation value to obtain a correlation degree value, and compares it with the correlation degree threshold value. If the correlation degree value is greater than or equal to the correlation degree threshold value, an adjustment analysis signal is generated, thereby reflecting the correlation degree between the thickness change of the printing plate area and the ink roller height change during the printing process by analyzing and processing multiple sets of previous printing data, and providing data support for the subsequent adjustment of the ink roller height;

[0053] (3) The present invention is based on the adjustment analysis signal, by integrating and merging adjacent printing sub-areas in the vertical direction of the printing path to obtain a merged sub-area, and analyzing whether there are only flat sub-areas or non-flat sub-areas in the merged sub-area. If there are only flat sub-areas, there is no need to adjust the ink roller height of the merged sub-area. If there are only non-flat sub-areas, the height adjustment coefficient is obtained, and the ink roller height is adjusted to perform printing. If there are flat areas and non-flat areas in the merged sub-area, when printing, first print according to the printing operation of the flat area, and then complete the printing according to the printing operation of the non-flat area. After the printing work of the merged sub-area on the PVC printed card is completed, the next merged sub-area is printed according to the preset printing path, thereby providing a printing method for PVC printed cards with uneven surfaces, solving the problem of blurred patterns or texts after printing due to uneven surface flatness of the PVC card. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] The present invention will be further described below in conjunction with the accompanying drawings.

[0055] Figure 1 This is a flow chart of the steps of Example 1 in a green printing process for PVC cards based on water-based ink of the present invention;

[0056] Figure 2 The invention discloses a flow chart of the steps of adjusting the ink roller height in a PVC card green printing process based on water-based ink. DETAILED DESCRIPTION

[0057] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further explained below in conjunction with specific implementation methods.

[0058] Example 1

[0059] like Figure 1 As shown, a green printing process for PVC cards based on water-based ink according to an embodiment of the present invention includes:

[0060] S1, selecting water-based ink as raw material;

[0061] S2, the PVC cards need to be pre-processed before printing, where the pre-processing includes cleaning, drying and surface flatness testing;

[0062] S3, printing is performed on the surface of the PVC card, and the printed PVC card is dried and cured.

[0063] Example 2

[0064] like Figure 1 As shown, a green printing process for PVC cards based on water-based ink according to an embodiment of the present invention includes:

[0065] Step 1: Process the printed area on the surface of the PVC printed card to obtain several printed sub-areas, obtain the printed sub-area data, wherein the printed sub-area data includes the printed sub-area thickness, process the printed sub-area thickness, output the thickness difference, and compare the thickness difference with the thickness difference range. If the thickness difference is not within the thickness difference range, that is, the thickness exceeds the range, the sub-area with the thickness exceeding the range is marked as a non-flat area;

[0066] In some embodiments, the printing area is divided into equal areas to obtain a plurality of printing sub-areas;

[0067] Obtain the thickness of the printed sub-area, add up the thickness of all printed sub-areas and take the average value to obtain the average thickness of the sub-areas;

[0068] Subtract the thickness of the printed sub-area from the average thickness of the sub-area to obtain the thickness difference;

[0069] The thickness difference is compared with the thickness difference range as follows:

[0070] If the thickness difference is not within the thickness difference range, that is, the thickness exceeds the range, the sub-region with the thickness exceeding the range is marked as a non-flat region;

[0071] If the thickness difference is within the thickness difference range, that is, the thickness is not out of range, the sub-region where the thickness is not out of range is marked as a flat region;

[0072] It should be noted that the non-flat area means: the printed sub-area where the thickness is significantly different from the average thickness of the printed area on the surface of the PVC printed card;

[0073] Step 2: Analyze the uneven area to obtain convex areas and concave areas, analyze and process the convex areas and concave areas, output the convexity and concave values ​​and convexity and concave degree values, process the convexity and concave values ​​and convexity and concave degree values, output the surface flatness value, and compare the surface flatness value with the surface flatness threshold. If the surface flatness value is greater than the surface flatness threshold, generate a thickness unevenness signal;

[0074] Specifically, the thickness difference corresponding to the non-flat area is obtained. If the thickness difference corresponding to the non-flat area is positive, the non-flat area with the positive thickness difference is marked as a convex area. If the thickness difference corresponding to the non-flat area is negative, the non-flat area with the negative thickness difference is marked as a concave area.

[0075] Count the number of convex areas and the number of concave areas to obtain the number of convex-concave areas, and calculate the ratio of the number of convex-concave areas in the printing area to the total number of printed sub-areas in the printing area to obtain a convex-concave value, which is marked as G;

[0076] Obtain the thickness difference corresponding to the convex area, add and average the thickness difference corresponding to the convex area, and obtain the convex thickness difference;

[0077] Calculate the ratio of the convex thickness difference value to the end point value of the thickness difference range to obtain the convex thickness difference coefficient;

[0078] Obtain the thickness difference corresponding to the concave area, add the thickness difference corresponding to the concave area to obtain the average value, and take the absolute value to obtain the concave thickness difference;

[0079] The concave thickness difference value is calculated by ratio with the end point value of the thickness difference range to obtain the concave thickness difference coefficient;

[0080] The convex thickness difference coefficient and the concave thickness difference coefficient are added together to obtain the convexity and concaveness value, which is marked as CD.

[0081] Substitute the convexity and concavity value G and the convexity and concavity degree value CD into the formula: The surface flatness value P is calculated, where α and β represent weight coefficients, α is 2.1365, and β is 1.6547;

[0082] It can be understood that the meaning of the surface flatness value is: the proportion of the number of convex areas and concave areas in the PVC printed card area, and the degree of deviation between the convex areas, concave areas and the average thickness of the overall PVC printed card area, reflects the flatness of the printed area on the surface of the PVC printed card. Specifically, if this value is larger, it means that the thickness difference of each sub-area in the printed area on the surface of the PVC printed card is larger. Conversely, if this value is smaller, it means that the thickness difference of each sub-area in the printed area on the surface of the PVC printed card is smaller.

[0083] The surface smoothness value is compared to the surface smoothness threshold as follows:

[0084] If the surface flatness value is greater than the surface flatness threshold, it means that the thickness of the printed sub-areas in the printed area on the surface of the PVC printed card is quite different, and a thickness unevenness signal is generated;

[0085] If the surface flatness value is less than or equal to the surface flatness threshold, it means that the thickness difference of the printed sub-areas in the printed area on the surface of the PVC printed card is small, and a thickness uniformity signal is generated;

[0086] The specific implementation scheme of the embodiment of the present invention is as follows: processing the printed area on the surface of the PVC printed card to obtain several printed sub-areas, obtaining the printed sub-area data, and analyzing and processing to obtain the non-flat area, analyzing the non-flat area to obtain the convex area and the concave area, analyzing and processing the convex area and the concave area, outputting the convex and concave values ​​and the convex and concave degree values, processing the convex and concave values ​​and the convex and concave degree values, and generating a thickness unevenness signal, thereby firstly analyzing the thickness of the printed sub-areas in the PVC printed card area to identify the non-flat area, and further analyzing the non-flat area to distinguish it into the convex area and the concave area, and obtaining the number ratio of the convex area and the concave area in the PVC printed card area, as well as the degree of deviation between the convex area, the concave area and the overall thickness mean of the PVC printed card area, reflecting the flatness of the printed area on the surface of the PVC printed card, and providing data for adjusting the printing parameters of the PVC printed card before printing.

[0087] Example 3

[0088] like Figure 1 - Figure 2 As shown, based on Example 1 and Example 2, a green printing process for PVC cards based on water-based ink described in an embodiment of the present invention includes:

[0089] Step 3: Based on the thickness unevenness signal, multiple groups of previous printing data are obtained, wherein the previous printing data include the ink roller height difference value and the previous thickness difference value, the ink roller height value and the previous thickness deviation value are analyzed and processed to obtain a correlation degree value, and compared with the correlation degree threshold value, if the correlation degree value is greater than or equal to the correlation degree threshold value, an adjustment analysis signal is generated;

[0090] Specifically, the previous printing plate area is divided into equal areas to obtain a plurality of previous printing sub-areas;

[0091] Obtaining the previous thickness difference value and the ink roller height difference value corresponding to the previous printing sub-area, and extracting the value of the previous thickness difference value and the ink roller height difference value corresponding to the previous printing sub-area;

[0092] It should be noted that the ink roller height difference represents the distance difference between the ink roller height during actual printing and the ink roller height during preset printing;

[0093] Specifically, if the actual printing ink roller height is lower than the preset printing ink roller height, the ink roller height difference is a negative number; if the actual printing ink roller height is higher than the preset printing ink roller height, the ink roller height difference is a positive number;

[0094] In the past, the thickness difference value represented the difference between the actual thickness of the printed sub-area on the PVC printed card during actual printing and the overall thickness of the printed sub-area;

[0095] Specifically, if the actual thickness of the printed sub-area on the PVC printed card during actual printing is higher than the overall thickness of the printed sub-area, the previous thickness difference is positive; if the actual thickness of the printed sub-area on the PVC printed card during actual printing is lower than the overall thickness of the printed sub-area, the previous thickness difference is negative;

[0096] The value of the thickness difference corresponding to the previous printing sub-area and the value of the ink roller height difference are randomly extracted, and the positive and negative values ​​are compared. The process is as follows:

[0097] If the value of the previous thickness difference corresponding to the previous printing sub-region and the value of the ink roller height difference have the same positive and negative values, the previous printing sub-regions with the same positive and negative values ​​are marked as related sub-regions;

[0098] If the value of the previous thickness difference corresponding to the previous printing sub-region and the value of the ink roller height difference are different in positive and negative, the previous printing sub-region with different positive and negative is marked as a non-related sub-region;

[0099] Obtaining the number of relevant sub-regions, calculating the ratio of the number of relevant sub-regions to the total number of previously printed sub-regions, and obtaining a relevant number ratio;

[0100] Based on the relevant sub-region, the value of the previous thickness difference of the relevant sub-region is calculated by ratio with the value of the ink roller height difference to obtain the relevant sub-coefficient;

[0101] All the correlation sub-coefficients are subjected to variance calculation to obtain the correlation coefficient;

[0102] Calculate the ratio of the relevant quantity ratio and the correlation coefficient to obtain the correlation degree value;

[0103] It can be understood that the meaning of the correlation degree value is: reflecting the correlation degree between the change in thickness of the printing plate area and the change in the height of the ink roller during the printing process. Specifically, if this value is larger, it means that the correlation degree between the change in thickness of the printing plate area and the change in the height of the ink roller during the printing process is larger. On the contrary, if this value is smaller, it means that the correlation degree between the change in thickness of the printing plate area and the change in the height of the ink roller during the printing process is smaller.

[0104] The correlation value is compared with the correlation threshold, and the process is as follows:

[0105] If the correlation value is greater than or equal to the correlation threshold, it means that the correlation between the thickness change of the printing plate area and the height change of the ink roller during the printing process is relatively large, and an adjustment analysis signal is generated;

[0106] If the correlation value is less than the correlation threshold, it means that the correlation between the thickness change of the printing plate area and the height change of the ink roller during the printing process is small, and an adjustment non-analysis signal is generated;

[0107] The specific implementation scheme of the embodiment of the present invention is: based on the thickness unevenness signal, multiple groups of previous printing data are obtained, wherein the previous printing data include the ink roller height difference and the thickness difference, the ink roller height value and the thickness deviation value are analyzed and processed to obtain a correlation degree value, and compared with the correlation degree threshold value, if the correlation degree value is greater than or equal to the correlation degree threshold value, an adjustment analysis signal is generated, thereby reflecting the correlation degree between the thickness change of the printing plate area and the ink roller height change during the printing process by analyzing and processing multiple groups of previous printing data, thereby providing data support for the subsequent adjustment of the ink roller height.

[0108] Example 4

[0109] like Figure 1 - Figure 2 As shown, based on Example 1, Example 2 and Example 3, a green printing process for PVC cards based on water-based ink described in an embodiment of the present invention includes:

[0110] Step 4: Based on the adjustment analysis signal, the merged sub-area is obtained, the merged sub-area is analyzed and processed, the height adjustment coefficient is obtained, and the height of the ink roller is adjusted to complete the printing work on the surface of the PCV printing plate;

[0111] In some embodiments, when the adjustment analysis signal is generated, adjacent printing sub-regions in a vertical direction of the preset printing path are integrated and merged to obtain a merged sub-region;

[0112] It should be noted that there are non-flat areas (convex areas and concave areas) and flat areas in the merged sub-area, and the total number of printed sub-areas in the merged sub-area is an odd number;

[0113] If there is only a flat area in the merged sub-area, there is no need to adjust the ink roller height during printing;

[0114] If there are only uneven areas in the merged sub-area, the ink roller height needs to be adjusted during printing. The process is as follows:

[0115] All relevant sub-coefficients are added and averaged to obtain the height adjustment coefficient, which is marked as K;

[0116] Acquire a non-flat region in the merged sub-region, wherein the non-flat region in the merged sub-region includes a convex region and a concave region;

[0117] Count the number of convex and concave regions in the merged sub-regions and compare them. The process is as follows:

[0118] If the number of convex regions in the merged sub-regions is greater than the number of concave regions, then the formula: H t =H d +H d × K, calculate the adjusted ink roller height H t , where H d is the current unadjusted ink roller height;

[0119] If the number of convex regions in the merged sub-region is less than the number of concave regions, then the formula: H t =H d -H d × K, calculate the adjusted ink roller height H t , where H d is the current unadjusted ink roller height;

[0120] If there are flat areas and non-flat areas in the merged sub-area, when printing is performed, printing is first performed according to the printing operation on the flat area, and then the printing operation is completed according to the printing operation on the non-flat area;

[0121] After the printing of the merged sub-area on the PVC printed card is completed, the next merged sub-area is printed according to the preset printing path;

[0122] The specific implementation scheme of the embodiment of the present invention is as follows: based on the adjustment analysis signal, adjacent printing sub-areas in the vertical direction of the printing path are integrated and merged to obtain a merged sub-area, and it is analyzed whether there are only flat sub-areas or non-flat sub-areas in the merged sub-area. If there are only flat sub-areas, there is no need to adjust the ink roller height of the merged sub-area. If there are only non-flat sub-areas, a height adjustment coefficient is obtained, and the ink roller height is adjusted to perform printing. If there are flat areas and non-flat areas in the merged sub-area, when printing, firstly print according to the printing operation of the flat area, and then complete the printing according to the printing operation of the non-flat area. After the printing work of the merged sub-area on the PVC printed card is completed, the next merged sub-area is printed according to the preset printing path, thereby providing a printing method for PVC printed cards with uneven surfaces, and solving the problem of blurred patterns or texts after printing due to the uneven flatness of the surface of the PVC card.

[0123] The above shows and describes the basic principles, main features and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A green printing process for PVC cards based on water-based ink, characterized by: include: Step 1: Process the printed area on the surface of the PVC printed card to obtain several printed sub-areas, obtain the printed sub-area data, wherein the printed sub-area data includes the printed sub-area thickness, process the printed sub-area thickness, output the thickness difference, and compare the thickness difference with the thickness difference range. If the thickness difference is not within the thickness difference range, that is, the thickness exceeds the range, the sub-area with the thickness exceeding the range is marked as a non-flat area; Step 2: Analyze the uneven area to obtain convex areas and concave areas, analyze and process the convex areas and concave areas, output the convexity and concave values ​​and convexity and concave degree values, process the convexity and concave values ​​and convexity and concave degree values, output the surface flatness value, and compare the surface flatness value with the surface flatness threshold. If the surface flatness value is greater than the surface flatness threshold, generate a thickness unevenness signal; Step 3: Based on the thickness unevenness signal, multiple groups of previous printing data are obtained, wherein the previous printing data include the ink roller height difference value and the previous thickness difference value, the ink roller height value and the previous thickness deviation value are analyzed and processed to obtain a correlation degree value, and compared with the correlation degree threshold value, if the correlation degree value is greater than or equal to the correlation degree threshold value, an adjustment analysis signal is generated; Step 4: Based on the adjustment analysis signal, the merged sub-area is obtained, the merged sub-area is analyzed and processed, the height adjustment coefficient is obtained, and the height of the ink roller is adjusted to complete the printing work on the surface of the PCV printing plate.

2. The green printing process for PVC cards based on water-based ink according to claim 1, characterized in that: The method for obtaining the non-flat area is: Divide the printing area into equal areas to obtain a number of printing sub-areas; Obtain the thickness of the printed sub-area, add up the thickness of all printed sub-areas and take the average value to obtain the average thickness of the sub-areas; Subtract the thickness of the printed sub-area from the average thickness of the sub-area to obtain the thickness difference; The thickness difference is compared with the thickness difference range as follows: If the thickness difference is not within the thickness difference range, that is, the thickness exceeds the range, the sub-region with the thickness exceeding the range is marked as a non-flat region.

3. The green printing process for PVC cards based on water-based ink according to claim 2 is characterized in that: The convex area and concave area are obtained as follows: The thickness difference corresponding to the non-flat area is obtained. If the thickness difference corresponding to the non-flat area is positive, the non-flat area with the positive thickness difference is marked as a convex area. If the thickness difference corresponding to the non-flat area is negative, the non-flat area with the negative thickness difference is marked as a concave area.

4. The green printing process for PVC cards based on water-based ink according to claim 1 is characterized in that: The surface flatness value is obtained as follows: Substitute the convexity and concavity value G and the convexity and concavity degree value CD into the formula: The surface flatness value P is calculated, where α and β represent weight coefficients, α is 2.1365, and β is 1.6547.

5. The green printing process for PVC cards based on water-based ink according to claim 1 is characterized in that: The way to obtain the convex and concave values ​​is: Count the number of convex areas and the number of concave areas to obtain the number of convex-concave areas, and calculate the ratio of the number of convex-concave areas in the printing area to the total number of printed sub-areas in the printing area to obtain a convex-concave value, which is marked as G; The convexity and concavity value is obtained as follows: Obtain the thickness difference corresponding to the convex area, add and average the thickness difference corresponding to the convex area, and obtain the convex thickness difference; Calculate the ratio of the convex thickness difference value to the end point value of the thickness difference range to obtain the convex thickness difference coefficient; Obtain the thickness difference corresponding to the concave area, add the thickness difference corresponding to the concave area to obtain the average value, and take the absolute value to obtain the concave thickness difference; The concave thickness difference value is calculated by ratio with the end point value of the thickness difference range to obtain the concave thickness difference coefficient; The convex thickness difference coefficient and the concave thickness difference coefficient are added together to obtain the convexity and concaveness value, which is marked as CD.

6. The green printing process for PVC cards based on water-based ink according to claim 1 is characterized by: The relevant sub-areas are obtained as follows: Dividing the previous printing plate area into equal areas to obtain a plurality of previous printing sub-areas; Obtaining the previous thickness difference value and the ink roller height difference value corresponding to the previous printing sub-area, and extracting the value of the previous thickness difference value and the ink roller height difference value corresponding to the previous printing sub-area; The value of the thickness difference corresponding to the previous printing sub-area and the value of the ink roller height difference are randomly extracted, and the positive and negative values ​​are compared. The process is as follows: If the value of the previous thickness difference corresponding to the previous printing sub-region and the value of the ink roller height difference have the same positive and negative values, the previous printing sub-regions with the same positive and negative values ​​are marked as related sub-regions.

7. The intelligent construction method based on digital twin according to claim 6, characterized in that: The way to obtain the correlation value is: Obtaining the number of relevant sub-regions, calculating the ratio of the number of relevant sub-regions to the total number of previously printed sub-regions, and obtaining a relevant number ratio; Based on the relevant sub-region, the value of the previous thickness difference of the relevant sub-region is calculated by ratio with the value of the ink roller height difference to obtain the relevant sub-coefficient; All the correlation sub-coefficients are subjected to variance calculation to obtain the correlation coefficient; The correlation coefficient is calculated by ratio calculation to obtain the correlation degree value.

8. The green printing process for PVC cards based on water-based ink according to claim 1 is characterized by: The height adjustment coefficient is obtained as follows: If there are only uneven areas in the merged sub-area, the ink roller height needs to be adjusted during printing. The process is as follows: All relevant sub-coefficients are added and averaged to obtain the height adjustment coefficient, which is marked as K.

9. The green printing process for PVC cards based on water-based ink according to claim 8, characterized in that: The ink roller height adjustment process is as follows: Acquire a non-flat region in the merged sub-region, wherein the non-flat region in the merged sub-region includes a convex region and a concave region; Count the number of convex and concave regions in the merged sub-regions and compare them. The process is as follows: If the number of convex regions in the merged sub-region is greater than the number of concave regions, then the formula: H t =H d +H d × K, calculate the adjusted ink roller height H t , where H d is the current unadjusted ink roller height; If the number of convex regions in the merged sub-region is less than the number of concave regions, then the formula: H t =H d -H d × K, calculate the adjusted ink roller height H t , where H d This is the current unadjusted ink roller height.

10. The green printing process for PVC cards based on water-based ink according to claim 1, characterized in that: If there are flat areas and non-flat areas in the merged sub-area, when printing is performed, printing is first performed according to the printing operation on the flat area, and then the printing operation is completed according to the printing operation on the non-flat area; After the printing of the merged sub-areas on the PVC printed card is completed, the next merged sub-area is printed according to the preset printing path.

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