Curved surface transfer printing compensation method, curved surface transfer printing system and printed matter
By comparing and computing the characteristic point coordinates of the initial pad printing image and the template pattern to generate compensation patterns, the problems of deformation and high cost of printing patterns in curved pad printing equipment are solved, and the cost-effective curved pad printing effect is achieved.
Patent Information
- Application Number
- CN202311592477.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-11-27
- Publication Date
- 2025-05-27
AI Technical Summary
When existing pad printing equipment performs curved surface pad printing, the printing pattern is deformed or skewed due to the deformation of the rubber head when pressing down, and the high-end pad printing equipment is expensive, which limits its wide application.
By identifying and sampling the coordinates of the feature point of the initial pad printing image, and generating compensation patterns based on the coordinate change results between the initial pad printing image and the template pattern, the surface pad printing compensation is completed.
It provides good surface pad printing effect without the need to configure professional surface pad printing function, and is suitable for general pad printing equipment and reduces costs.
Smart Images
Figure CN120039051A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a pad printing method and a pad printing system, and in particular to a curved surface pad printing compensation method, a curved surface pad printing system and a printed product. Background Art
[0002] When general pad printing equipment is used to pad print on the curved surface of a product, the pad printing head will be deformed due to the different contact conditions when it is pressed down from the ink flat steel plate used for pad printing, which will cause the pad printing head to deform or skew the printed pattern. In addition to the above problems caused by the curved surface of the product, the surface concave-convex structure of the product (such as blind convex points and holes) will also aggravate the local deformation of the pad printing head.
[0003] Existing high-end pad printing equipment with curved pad printing technology relies heavily on professional curved pad printing functions, such as being equipped with a stage that can rotate the product itself during the pad printing process. However, high-end pad printing equipment is expensive, and due to cost constraints, manufacturers are unable to afford it and are stuck in the current situation.
[0004] In view of this, there is currently a lack of a pad printing system in the market that can achieve good curved surface pad printing effects without the need for configuring a professional curved surface pad printing function, so relevant industry players are all seeking a solution.
[0005] Therefore, it is necessary to provide a curved surface pad printing compensation method, a curved surface pad printing system and a printed product to solve the above problems. Summary of the invention
[0006] The purpose of the present invention is to provide a curved surface pad printing compensation method and a curved surface pad printing system, which completes the curved surface pad printing compensation by identifying and sampling the coordinates of the feature points of the initial pad printing image, and generating a compensation pattern based on the coordinate change results between the initial pad printing image and the template pattern. In addition to being applicable to general pad printing equipment, it can also provide a good curved surface pad printing effect.
[0007] According to one embodiment of the method aspect of the present invention, a curved pad printing compensation method is provided, which includes an import step, an identification step, a sampling step, a comparison step and a compensation step. The import step includes driving a processor to obtain a template pattern and an initial pad printing image, and the template pattern includes a plurality of sample feature points and a sample feature point coordinate corresponding to each sample feature point. The identification step includes driving the processor to identify the initial pad printing image to generate a plurality of feature points, and each feature point corresponds to each sample feature point. The sampling step includes driving the processor to sample the coordinates of each feature point, and generate a feature point coordinate corresponding to each feature point. The comparison step includes driving the processor to compare the feature point coordinates with the sample feature point coordinates to generate a coordinate change result. The compensation step includes driving the processor to generate a compensation pattern based on the coordinate change result and the template pattern calculation.
[0008] According to the present invention, a printed product is provided which includes a pad-printed pattern compensated by the curved pad-printing compensation method as described in the previous paragraph.
[0009] According to an embodiment of the structural aspect of the present invention, a curved surface pad printing system is provided, comprising a memory, a processor and a printing device. The memory stores a template pattern, and the template pattern comprises a plurality of sample feature points and a sample feature point coordinate corresponding to each sample feature point. The processor is connected to the memory, and the processor is configured to implement an import step, an identification step, a sampling step, a comparison step and a compensation step. The import step comprises obtaining a template pattern and an initial pad printing image. The identification step comprises identifying the initial pad printing image to generate a plurality of feature points, each feature point corresponding to each sample feature point. The sampling step comprises sampling the coordinates of each feature point, and generating a feature point coordinate corresponding to each feature point. The comparison step comprises comparing the feature point coordinates with the sample feature point coordinates to generate a coordinate change result. The compensation step comprises generating a compensation pattern based on the coordinate change result and the template pattern calculation. The printing device is connected to the processor, and is used to pad print a semi-finished product based on the template pattern and the compensation pattern. BRIEF DESCRIPTION OF THE DRAWINGS
[0010] Figure 1 A block diagram of a curved surface pad printing system according to a first embodiment of the present invention is shown;
[0011] Figure 2 A block flow chart of a curved surface pad printing compensation method according to a second embodiment of the present invention is shown;
[0012] Figure 3 Draw Figure 2 A schematic diagram of integrating the template pattern and the initial pad printing image in the import step in the second embodiment;
[0013] Figure 4 Draw Figure 2 A schematic diagram of feature points of an initial pad printing image and sample feature points of a template pattern in a second embodiment;
[0014] Figure 5 Draw Figure 2 The curved surface pad printing compensation method of the second embodiment is based on Figure 4 A schematic diagram of a compensation pattern for performing compensation;
[0015] Figure 6A A top view of a printed product showing a third embodiment of the present invention; and
[0016] Figure 6B A front view of a printed product according to a third embodiment of the present invention is shown.
[0017] Main component symbols:
[0018] 100 Curved Surface Pad Printing System
[0019] 110 Printing equipment
[0020] 120 Memory
[0021] 130 processors
[0022] 140 Image capture device
[0023] 200 Curved surface pad printing compensation method
[0024] 300 Prints
[0025] 310 Pad Printing Pattern
[0026] 320 Non-planar
[0027] S01 Initial printing step
[0028] S02 Initial capture step
[0029] S03 Import Steps
[0030] S04 Identification Steps
[0031] S05 Sampling steps
[0032] S06 Comparison steps
[0033] S07 Compensation Steps
[0034] S071 First operation step
[0035] S072 Second operation step
[0036] S073 The third operation step
[0037] S08 Printing Steps
[0038] S09 Capture Steps
[0039] S10 Compensation result confirmation steps
[0040] S11 Angle Adjustment Steps
[0041] S12 Output Step
[0042] B Initial pad printing image
[0043] C Compensation pattern
[0044] D Pad printing image
[0045] P1 sample feature points
[0046] P2 feature points
[0047] S Template DETAILED DESCRIPTION
[0048] Please also read Figure 1 and Figure 2 ,in Figure 1 A block diagram of a curved surface pad printing system 100 according to a first embodiment of the present invention is shown; and Figure 2 A block flow chart of a curved pad printing compensation method 200 according to a second embodiment of the present invention is shown. The curved pad printing system 100 is configured to implement the curved pad printing compensation method 200 to compensate for the deformation and deflection of the pad printing pattern to obtain a good curved pad printing effect. It must be noted that the curved pad printing compensation method 200 of the present invention is not limited to being implemented by the curved pad printing system 100 of the present invention, and the various components in the curved pad printing system 100 can be arbitrarily integrated into various combinations to perform the functions of the curved pad printing compensation method 200.
[0049] exist Figure 1 In the invention, the curved pad printing system 100 comprises a printing device 110, a memory 120, a processor 130 and an image capture device 140, wherein the processor 130 is connected to the printing device 110, the memory 120 and the image capture device 140. The printing device 110 is used to perform pad printing on a semi-finished product according to a template pattern S to produce an initial printed product, and to perform pad printing on the semi-finished product according to a compensation pattern C to produce a compensated printed product. The memory 120 is used to store the template pattern S. The image capture device 140 is used to photograph the initial printed product and the compensated printed product to produce an initial pad printing image B and a pad printing image D respectively. The processor 130 is used to implement the curved pad printing compensation method 200, and can perform curved surface compensation according to the initial pad printing image B to produce the compensation pattern C, and can confirm whether to further adjust the angle of the compensation pattern C according to the pad printing image D, so as to achieve the best compensation effect. In the first embodiment, the memory 120 may be a random access memory (RAM) or other types of dynamic storage devices that can store information and instructions for the processor 130 to execute; the processor 130 may be a processor, a microprocessor, a central processing unit (CPU), a computer, a mobile device processor, a cloud processor or other electronic computing processors; the image capture device 140 may be a camera or a mobile phone camera, but the present invention is not limited thereto.
[0050] Please also read Figures 1 to 3 , Figure 3 Draw Figure 2Schematic diagram of integrating the template pattern S and the initial pad printing image B in the import step S03 in the second embodiment. The curved pad printing compensation method 200 includes an initial printing step S01, an initial capture step S02, an import step S03, an identification step S04, a sampling step S05, a comparison step S06 and a compensation step S07, which are sequentially performed. The initial printing step S01 includes driving the printing device 110 to pad print the semi-finished product according to the template pattern S to generate an initial printed product. The initial capture step S02 includes driving the image capture device 140 to shoot the initial printed product to generate the initial pad printing image B. The import step S03 includes driving the processor 130 to obtain the template pattern S from the memory 120, obtain the initial pad printing image B generated by shooting the initial printed product from the image capture device 140, and drive the processor 130 to integrate the template pattern S with the initial pad printing image B. The template pattern S may be a wireframe or a two-dimensional pattern of a printed pattern, and includes a plurality of sample feature points P1 and a sample feature point coordinate corresponding to each sample feature point P1 ( Figure 3 The sample feature point P1 is not shown).
[0051] Further explanation: Figure 3 In the figure, the initial pad printing image B is the printed pattern “Phone” on the initial printed product, and the template pattern S is the wireframe of the printed pattern “Phone”. In the import step S03, the processor 130 overlays the template pattern S onto the initial pad printing image B and integrates the template pattern S with the initial pad printing image B. At this time, it can be observed that the printed pattern on the initial printed product tends to be skewed compared to the template pattern S.
[0052] Please also read Figures 1 to 4 , Figure 4 Draw Figure 2 Schematic diagram of feature points P2 of the initial pad-printed image B and sample feature points P1 of the template pattern S in the second embodiment. The identification step S04 includes driving the processor 130 to identify the initial pad-printed image B to generate a plurality of feature points P2, and these feature points P2 correspond to the sample feature points P1 of the template pattern S. The sample feature points P1 and the feature points P2 include at least one moving point and at least one fixed point. The at least one moving point can be the vertex of the curve, the point with the maximum curvature change, or the intersection point of the fillet and the straight line in the template pattern S. The at least one fixed point can be the uppermost point or the lowermost point in the template pattern S. In the second embodiment, the number of the sample feature points P1 and the number of the feature points P2 are both 4, but the present invention is not limited thereto.
[0053] Further explanation: Figure 4In the figure, taking the printed pattern "h" as an example, among the sample feature points P1 and P2, the moving point corresponding to the printed pattern "h" is the intersection of the fillet and the straight line at the upper left, and the vertex of the curve at the upper right; the fixed point corresponding to the printed pattern "h" is the lowest point of the template pattern S at the lower right.
[0054] The sampling step S05 includes driving the processor 130 to sample the coordinates of the feature points P2, and generating a feature point coordinate corresponding to each feature point P2. The comparison step S06 includes driving the processor 130 to compare the coordinates of each feature point with the coordinates of each sample feature point to generate a coordinate change result. The compensation step S07 includes driving the processor 130 to generate a compensation pattern C based on the coordinate change result and the template pattern S to complete the curved pad printing compensation. In the second embodiment, the sample feature point coordinates and the feature point coordinates are both two-dimensional coordinates.
[0055] The compensation step S07 further includes a first operation step S071, a second operation step S072, and a third operation step S073. The first operation step S071 includes driving the processor 130 to generate a skew matrix by a linear mapping method according to the coordinate change result. The second operation step S072 includes driving the processor 130 to generate a generalized inverse matrix according to the skew matrix operation. The third operation step S073 includes driving the processor 130 to generate a compensation pattern C according to the generalized inverse matrix and the template pattern S. Specifically, the processor 130 multiplies the generalized inverse matrix and the template pattern S to generate the compensation pattern C.
[0056] To further illustrate, the derivation of the skew matrix and the compensation pattern C is as follows:
[0057] Assume that the number of sample feature points P1 and feature points P2 defined by the template pattern S and the initial pad printing image B is 4. The sample feature point coordinate matrix of the template pattern S and the feature point coordinate matrix of the initial pad printing image B are respectively as follows:
[0058]
[0059]
[0060] Wherein, A is the sample feature point coordinate matrix of the template pattern S; A' is the feature point coordinate matrix of the initial pad printing image B.
[0061] The calculation of the skew matrix is as follows:
[0062] F=A′A T (A′A T ) -1 .
[0063] Among them, F is the skew matrix; AT is the transposed matrix of the sample feature point coordinate matrix.
[0064] The calculation of compensation pattern C is as follows:
[0065] C=F -1 A.
[0066] Among them, C is the compensation pattern; F -1 is the generalized inverse of the skew matrix.
[0067] Please also read Figures 1 to 5 , Figure 5 Draw Figure 2 The curved surface pad printing compensation method 200 of the second embodiment is based on Figure 4 Schematic diagram of compensation pattern C for compensation. Figure 4 The coordinate change results of the initial pad printing image B and the template pattern S are illustrated by way of example.
[0068] In the first operation step S071, the coordinate change result can be operated according to the linear mapping method to generate a skew matrix
[0069] In the second operation step S072, the generalized inverse matrix of the skew matrix is calculated to generate the generalized inverse matrix
[0070]
[0071] In the third operation step S073, the generalized inverse matrix is multiplied by the template pattern S to generate a compensation pattern C. Figure 4 It can be seen that the upper half of the initial pad printing image B is offset to the left and upward compared to the template pattern S. Figure 5 It can be seen that after the compensation calculation, the upper half of the compensation pattern C is slightly biased to the right compared to the initial pad printing image B, thereby achieving a skew compensation effect.
[0072] Please also read Figures 1 to 2 The curved surface pad printing compensation method 200 may further include a printing step S08, a capture step S09, a compensation result confirmation step S10, an angle adjustment step S11, and an output step S12. The printing step S08 and the capture step S09 are sequentially performed after the compensation step S07, and the angle adjustment step S11 and the output step S12 are performed after the compensation result confirmation step S10. The printing step S08 includes driving the printing device 110 to pad print the semi-finished product according to the compensation pattern C to generate a compensated printed product. The capture step S09 includes driving the image capture device 140 to shoot the compensated printed product to generate a pad printing image D.
[0073] The compensation result confirmation step S10 includes driving the processor 130 to measure the degree of skewness of the printed pattern of the pad printing image D, and confirming whether an angle difference between the pad printing image D and the template pattern S is greater than or equal to a threshold value to generate a confirmation result, and outputting the compensation pattern C according to the confirmation result. When the confirmation result is yes, the angle adjustment step S11 is executed, and the angle adjustment step S11 includes driving the processor 130 to rotate and correct the compensation pattern C according to the angle difference, and repeatedly executing the printing step S08, the capturing step S09 and the compensation result confirmation step S10. When the confirmation result is no, the output step S12 is executed to output the compensation pattern C as the final compensation pattern C to complete the curved pad printing compensation.
[0074] It should be noted that the number and position of the sample feature points P1 and P2 will slightly affect the calculation of the skew matrix in the compensation step S07, and there is a possibility that the compensation pattern C is over-compensated or has an angle difference. Therefore, it is necessary to confirm through the compensation result confirmation step S10 to further optimize the compensation pattern C.
[0075] Please also read Figure 1 , Figure 2 , Figure 6A as well as Figure 6B ,in Figure 6A A top view of a printed product 300 showing a third embodiment of the present invention; and Figure 6B A front view of a printed product 300 according to a third embodiment of the present invention is shown. The printed product 300 is printed with a pad printing pattern 310, and a portion of the pad printing pattern 310 is located at or adjacent to a non-planar portion 320 of the printed product 300, and the non-planar portion 320 is a curved surface, a convex point, or a hole structure. In the third embodiment, the printed product 300 is a compensated printed product produced by pad printing a semi-finished product according to the compensation pattern C by the printing device 110 after compensation by the curved surface pad printing compensation method 200 in the first and second embodiments.
[0076] From the above embodiments, it can be seen that the present invention has the following advantages: First, by calculating the coordinate change result between the initial pad printing image and the template pattern to generate a compensation pattern, it is possible to quickly achieve compensation for the curved pad printing and provide a good curved pad printing effect. Second, by using the compensation pattern to improve the problem of curved pad printing deformation and deflection, it can be applied to general pad printing equipment without the need to configure a professional curved pad printing function, thereby greatly saving costs.
[0077] Although the present invention has been disclosed in the form of an implementation method as above, it is not intended to limit the present invention. Any technician in this field should be able to make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the invention should be based on the scope defined by the attached claims.
Claims
1. A method for compensating for curved surface pad printing, the method for compensating for curved surface pad printing comprises: An importing step, the importing step includes driving a processor to obtain a template pattern and an initial pad printing image, the template pattern includes a plurality of sample feature points and a sample feature point coordinate corresponding to each of the sample feature points; An identifying step, the identifying step includes driving the processor to identify the initial pad printing image to generate a plurality of feature points, the feature points corresponding to the sample feature points; A sampling step, the sampling step includes driving the processor to perform coordinate sampling on the feature points to generate a feature point coordinate corresponding to the feature points; A comparing step, the comparing step includes driving the processor to compare the feature point coordinate and the sample feature point coordinate to generate a coordinate change result; and A compensating step, the compensating step includes driving the processor to calculate and generate a compensation pattern according to the coordinate change result and the template pattern.
2. The method for compensating for curved surface pad printing according to claim 1, wherein the compensating step further comprises: A first calculating step, the first calculating step includes driving the processor to generate a skew matrix by linear mapping calculation according to the coordinate change result; A second calculating step, the second calculating step includes driving the processor to calculate and generate a generalized inverse matrix according to the skew matrix; and A third calculating step, the third calculating step includes driving the processor to generate the compensation pattern according to the generalized inverse matrix and the template pattern.
3. The method for compensating for curved surface pad printing according to claim 2, wherein in the third calculating step, the processor multiplies the generalized inverse matrix by the template pattern to generate the compensation pattern.
4. The method for compensating for curved surface pad printing according to claim 1, wherein the sample feature points and the feature points include at least one moving point and at least one fixed point; wherein, The at least one moving point may be a curve vertex, a point with the largest curvature change or an intersection point of a fillet and a straight line in the template pattern, and the at least one fixed point may be the uppermost point or the lowermost point in the template pattern.
5. The method for compensating for curved surface pad printing according to claim 1, wherein the importing step further includes driving the processor to integrate the template pattern and the initial pad printing image.
6. The method for compensating for curved surface pad printing according to claim 1, the method for compensating for curved surface pad printing further comprises: A printing step, the printing step includes driving a printing device to pad print a semi-finished product according to the compensation pattern to generate a compensated printed product; and An extracting step, the extracting step includes driving an image capturing device to capture the compensated printed product to generate a pad printing image.
7. The method for compensating for curved surface pad printing according to claim 6, the method for compensating for curved surface pad printing further comprises: A compensation result confirmation step, the compensation result confirmation step includes driving the processor to confirm whether an angle difference between the pad printing image and the template pattern is greater than or equal to a threshold value to generate a confirmation result, and output the compensation pattern according to the confirmation result; wherein, when the confirmation result is negative, output the compensation pattern to complete the compensation for curved surface pad printing.
8. The method for compensating for curved surface pad printing according to claim 7, wherein when the confirmation result is positive, the method for compensating for curved surface pad printing further Comprising: An angle adjustment step, which includes driving the processor to rotate and correct the compensation pattern according to the angle difference, and repeatedly executing the printing step, the capturing step, and the compensation result confirmation step.
9. The curved surface pad printing compensation method according to claim 1, the curved surface pad printing compensation method further Comprising: An initial printing step, which includes driving a printing device to pad print a semi-finished product according to the template pattern to generate an initial printed product; And An initial capturing step, which includes driving an image capturing device to capture the initial printed product to generate the initial pad printing image.
10. A printed product with a pad printing pattern compensated by the curved surface pad printing compensation method according to any one of claims 1 to 9.
11. The printed product according to claim 10, wherein part of the pad printing pattern is located at or adjacent to a non-planar part of the printed product.
12. A curved surface pad printing system, the curved surface pad printing system Comprising: A memory that stores a template pattern, the template pattern includes a plurality of sample feature points and a sample feature point coordinate corresponding to each of the sample feature points; A processor, the processor is connected to the memory, and the processor is configured to perform operations including the following steps: An importing step, which includes obtaining the template pattern and an initial pad printing image; An identifying step, which includes identifying the initial pad printing image to generate a plurality of feature points, and these feature points correspond to the sample feature points; A sampling step, which includes sampling the coordinates of these feature points to generate a feature point coordinate corresponding to these feature points; A comparing step, which includes comparing the feature point coordinate and the sample feature point coordinate to generate a coordinate change result; and A compensating step, which includes calculating and generating a compensation pattern according to the coordinate change result and the template pattern; and A printing device, the printing device is connected to the processor and is used to pad print a semi-finished product according to the template pattern and the compensation pattern.
13. The curved surface pad printing system according to claim 12, wherein the compensating step further Comprising: A first calculation step, which includes generating a skew matrix by linear mapping calculation according to the coordinate change result; A second calculation step, which includes calculating and generating a generalized inverse matrix according to the skew matrix; and A third calculation step, which includes generating the compensation pattern according to the generalized inverse matrix and the template pattern.
14. The curved surface pad printing system according to claim 13, wherein in the third calculation step, the processor multiplies the generalized inverse matrix and the template pattern to generate the compensation pattern.
15. The curved surface pad printing system according to claim 12, wherein the sample feature points and the feature points include at least one moving point and at least one fixed point; Wherein, The at least one moving point can be a curve vertex, a point with the largest curvature change, or an intersection point of a fillet and a straight line in the template pattern, and the at least one fixed point can be the uppermost point or the lowermost point in the template pattern.
16. The curved surface pad printing system according to claim 12, wherein the importing step further includes integrating the template pattern with the initial pad printing image.
17. The curved surface pad printing system according to claim 12, the curved surface pad printing system further comprises: An image capturing device, which is connected to the processor and is used for photographing an initial printed product and a compensated printed product generated by pad printing of the printing device to respectively generate the initial pad printing image and a pad printing image.
18. The curved surface pad printing system according to claim 17, wherein the processor further performs operations including the following steps: A compensation result confirmation step, which includes confirming whether an angle difference between the pad printing image and the template pattern is greater than or equal to a threshold value to generate a confirmation result, and outputting the compensated pattern according to the confirmation result; wherein, when the confirmation result is negative, output the compensated pattern to complete the curved surface pad printing compensation.
19. The curved surface pad printing system according to claim 18, wherein when the confirmation result is positive, the processor further performs operations including the following steps: An angle adjustment step, which includes rotating and correcting the compensated pattern according to the angle difference.