Printer step correction method and device based on visual recognition

Abstract

The application provides a printer step correction method and device based on visual recognition, which comprises a printing device, an image acquisition unit and a processor unit. When the printing device prints a printing medium in a printing platform area, a standard pattern with a standard size is printed in two steps. The image acquisition unit is installed on the printing platform area of the printing device, used to acquire the standard pattern printed on the surface of the printing medium in the printing platform area and send the standard pattern to the processor unit. The processor unit acquires image information of the standard pattern and identifies actual size data of the standard pattern. The processor unit compares the difference between the actual size data of the standard pattern and the standard size data set by a program in the advancing direction of the printing medium, and adjusts the step value of the printing device according to the difference. The application can correct the step and improve the printing quality by correcting the deformation of the printing pattern caused by the deformation of the printing medium during the printing process.

Description

Technical Field

[0001] This invention relates to the field of printer technology, and more specifically, to a method and apparatus for printer step correction based on visual recognition. Background Technology

[0002] Inkjet printers are the most common printing equipment in the advertising industry, and with the development of technology, related technologies are constantly evolving and progressing.

[0003] In terms of printing efficiency, inkjet printers have evolved into high-speed printers with a wide range of advancements. The reciprocating speed of the printing carriage is constantly increasing, and the printing efficiency is also constantly improving.

[0004] In terms of printing materials, paper is becoming increasingly thinner and its properties are becoming more sensitive. Different degrees of stretch may appear on the inside and outside of the same roll of paper.

[0005] In addition, printing materials are constantly evolving, with a wide range of materials such as paper, cloth, silk, and UV film.

[0006] Finally, people are demanding higher and higher printing precision, requiring more exquisite printed images and richer colors.

[0007] These factors not only pose challenges to the hardware configuration of printing equipment, but also require adjustments to printing technology.

[0008] As mentioned earlier, with the increasing thickness of the printing material roll, the inner and outer roll portions of the same material have different extensibility, resulting in inconsistent stretching of the same roll of material during the printing process, which ultimately affects the printing quality.

[0009] Currently, printer step correction can only be set based on known offsets. This process mainly relies on manual intervention, requiring professionals to continuously adjust and correct the printer's step rhythm during the printing process. This is inconvenient and also demands a high level of professional skill from the workers.

[0010] In order to solve the above problems, people have been seeking an ideal technological solution. Summary of the Invention

[0011] The purpose of this invention is to address the shortcomings of existing technologies by providing a vision-based printer step correction method and apparatus for correcting print image distortion caused by the stretching and deformation of the printing medium, thereby adapting the step setting value to the deformation of the printing medium and improving print quality.

[0012] To achieve the above objectives, the technical solution adopted by this invention is: a printer step-by-step correction method based on visual recognition, comprising a printing device, an image acquisition unit, and a processor unit, which is executed through the following method: When the printing equipment prints on the printing medium in the printing platform area, it prints a standard graphic with standard dimensions on the surface of the printing medium. The standard graphic is printed according to the following strategy: In two adjacent stepping processes, the first stepping stage prints the first part of the standard graphic, and the second stepping stage prints the second part of the standard graphic. The first part and the second part are spliced ​​together to form the standard graphic. The image acquisition unit is installed in the printing platform area of ​​the printing device to acquire standard graphics printed on the surface of the printing medium at the printing platform and send them to the processor unit. The processor unit acquires image information of the standard graphic and identifies the actual size data of the standard graphic; The processor unit compares the difference between the actual size data of the standard graphic and the standard size data set by the program in the direction of travel on the printing medium, and adjusts the step value of the printing device according to the difference.

[0013] Based on the above, the standard graphic is printed in the waste edge area of ​​the printing medium.

[0014] Based on the above, the standard graphic is a graphic that has a length dimension in the direction of travel of the printing medium.

[0015] Based on the above, the standard graphic is a square or rectangle, a line segment extending along the direction of travel of the printing medium, or two points at a fixed interval along the direction of travel of the printing medium.

[0016] Based on the above, the length of the standard graphic along the direction of travel of the printing medium is adapted to the step value of the printing device.

[0017] Based on the above, within a step distance, print the second part of the previous standard graphic and the first part of the next standard graphic.

[0018] Based on the above, the image acquisition unit is located on the downstream side of the printing platform along the direction of travel of the printing medium.

[0019] A printer step correction device based on vision recognition is used to execute the printer step correction method based on vision recognition. It includes the printing device, the image acquisition unit, and the processor unit.

[0020] Based on the above, the image acquisition unit is an industrial camera or a CCD camera.

[0021] Based on the above, standard graphics are printed on both sides of the waste edges of the printing medium. Two image acquisition units are provided, which are respectively set above the printing platforms on both sides of the printing medium, and are used to acquire images of the standard graphics on both sides of the waste edges of the printing medium.

[0022] This invention has outstanding substantive features and significant progress compared to the prior art. Specifically, this invention has the following advantages: When the printing medium stretches and deforms to different degrees due to varying humidity levels between the inner and outer rolls, the original step setting will not match the deformed printing medium, resulting in a distorted printed image. This invention prints a standard image on the surface of the printing medium simultaneously with the printed image. This standard image is created by stitching together print jobs from two stepping actions. The image is then read using image recognition, and its dimensions are identified and compared with the set dimensions of the standard image. If a difference exists, it indicates that the printed standard image is deformed, further suggesting that the printing medium has undergone stretching deformation and the step setting has deviated. The step setting is adjusted based on this difference to eliminate it. This dynamic and automated process ensures that the step setting always matches the deformation of the printing medium, ultimately guaranteeing the printing effect. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the printer step correction method based on visual recognition in this invention.

[0024] Figure 2 This is a standard graphical schematic diagram of the stretching deformation growth in this invention.

[0025] Figure 3 This is a standard graphic schematic diagram of the shortened shape after stretching deformation in this invention.

[0026] In the diagram: 1. Image acquisition unit; 2. Printing platform; 3. Printing medium; 4. Standard graphic; 5. Processor unit. Detailed Implementation

[0027] The technical solution of the present invention will be further described in detail below through specific embodiments.

[0028] Example 1 like Figures 1-3 As shown, a vision-based printer step correction method includes a printing device, an image acquisition unit 1, and a processor unit, and is executed through the following method: When the printing device prints on the printing medium 3 in the printing platform 2 area, it prints a standard graphic 4 with standard dimensions on the surface of the printing medium 3. The standard graphic is printed according to the following strategy: In two adjacent stepping processes, the first stepping stage prints the first part of the standard graphic, and the second stepping stage prints the second part of the standard graphic. The first part and the second part are spliced ​​together to form the standard graphic.

[0029] In this embodiment, to avoid interfering with the product pattern, the standard graphic 4 is printed on the waste edge area of ​​the printing medium.

[0030] Since the deformation of the printing medium mainly comes from the stretching caused by the printing medium in the direction of travel, the standard graphic 4 needs to be able to reflect the dimensional changes in the direction of travel of the printing medium. Therefore, in this embodiment, a square graphic is selected.

[0031] The image acquisition unit 1 is installed in the printing platform 2 area of ​​the printing device to acquire the standard graphic 4 printed on the surface of the printing medium 3 at the printing platform 2 and send it to the processor unit 5.

[0032] In this embodiment, the image acquisition unit 1 can be a CCD camera. In other embodiments, an industrial camera can also be used, which needs to have sufficient resolution to accurately acquire the size information of the standard graphic.

[0033] The processor unit 5 acquires the image information of the standard graphic 4 and identifies the actual size data of the standard graphic 4.

[0034] The processor unit 5 compares the difference between the actual size data of the standard graphic 4 and the standard size data set by the program in the direction of travel on the printing medium, and adjusts the step value of the printing device according to the difference.

[0035] Technical principle explanation: Taking a roll of thin printing paper stored in a relatively humid environment as an example, during storage, due to the influence of environmental humidity, the outer roll of the paper roll will have a higher humidity than the inner roll. During the printing process, since the printing medium needs to be tensioned to ensure flatness, a certain degree of deformation will occur. Paper with higher humidity will deform more than paper with lower humidity. This is the premise.

[0036] After the paper is loaded and printing begins, the printing medium is stretched and flattened. As it passes the printing platform, the printing carriage prints a standard shape, namely a square, on the waste edge area of ​​the printing medium.

[0037] However, due to the irregularity of the printing medium's outward curl deformation being large and its inward curl deformation being small, the printed square will have shorter sides as the deformation of the printing medium decreases, resulting in a difference in size from the standard graphic. Figure 3 As shown.

[0038] At this time, the image acquisition unit 1 acquires the stretched deformed graphic and sends the deformed graphic to the processor unit. The processor unit obtains the actual size of the deformed graphic through image analysis.

[0039] By comparing the actual size with the standard size set in the program, it was found that the side length of the graphic along the stepping direction was shortened. Then, the stepping setting value of the printing device was adjusted to reduce the stepping setting value synchronously, which compensated for the graphic deformation error caused by the deformation of the printing medium, thereby eliminating the deformation of the printed image.

[0040] This process is continuously adjusted throughout the printing process. In other embodiments, for situations where the outer roll has low humidity and the inner roll has high humidity, such as... Figure 2 As shown, the step setting value should also be increased synchronously from small to large.

[0041] In other embodiments, the standard graphic is a rectangle, a line segment extending along the printing medium travel direction, or two points at fixed intervals along the printing medium travel direction. It should be noted that since the main thing to know is the dimensional change in the stepping direction, the dimensional data of the stepping direction is required.

[0042] In a preferred embodiment, within a step distance, the second part of the previous standard graphic and the first part of the next standard graphic are printed so that the graphic at the current step distance can be continuously judged.

[0043] In other embodiments, the image acquisition unit is located on the downstream side of the printing platform along the direction of travel of the printing medium. The image on the downstream side is relatively complete and stable, and can better reflect the deformation.

[0044] Example 2 A printer step correction device based on vision recognition is used to execute the printer step correction method based on vision recognition. It includes the printing device, the image acquisition unit, and the processor unit, wherein the image acquisition unit is an industrial camera or a CCD camera.

[0045] In other embodiments, standard graphics are printed on the waste edges of both sides of the printing medium. Two image acquisition units are provided, each located above the printing platform on both sides of the printing medium, for acquiring images of the standard graphics on the waste edges of the printing medium.

[0046] In this embodiment, the deformation on both sides may be different, indicating that the printing medium itself has shifted. At this time, it is necessary to perform a correction operation on the printing medium itself. This correction process needs to be manually executed, so an alarm can usually be connected.

[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them; although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications can still be made to the specific implementation of the present invention or equivalent substitutions can be made to some technical features without departing from the spirit of the technical solutions of the present invention, and all such modifications and substitutions should be covered within the scope of the technical solutions claimed in the present invention.

Claims

1. A printer step correction method based on visual recognition, characterized in that: Including printing equipment, image acquisition unit, and processor unit, it is executed through the following methods: When the printing equipment prints on the printing medium in the printing platform area, it prints a standard graphic with standard dimensions on the surface of the printing medium. The standard graphic is printed according to the following strategy: In two adjacent stepping processes, the first stepping stage prints the first part of the standard graphic, and the second stepping stage prints the second part of the standard graphic. The first part and the second part are spliced ​​together to form the standard graphic. The image acquisition unit is installed in the printing platform area of ​​the printing device to acquire standard graphics printed on the surface of the printing medium at the printing platform and send them to the processor unit. The processor unit acquires image information of the standard graphic and identifies the actual size data of the standard graphic; The processor unit compares the difference between the actual size data of the standard graphic and the standard size data set by the program in the direction of travel on the printing medium, and adjusts the step value of the printing device according to the difference.

2. The printer step correction method based on visual recognition according to claim 1, characterized in that: The standard graphic is printed in the waste edge area of ​​the printing medium.

3. The printer step correction method based on visual recognition according to claim 1 or 2, characterized in that: The standard graphic is a graphic that has a length dimension in the direction of travel of the printing medium.

4. The printer step correction method based on visual recognition according to claim 3, characterized in that: The standard graphic is a square or rectangle, a line segment extending along the direction of travel of the printing medium, or two points at a fixed interval along the direction of travel of the printing medium.

5. The printer step correction method based on visual recognition according to claim 1, 2, or 4, characterized in that: The length of the standard graphic along the direction of travel on the printing medium is adapted to the step value of the printing device.

6. The printer step correction method based on visual recognition according to claim 1, 2, or 4, characterized in that: Print the second part of the previous standard graphic and the first part of the next standard graphic within one step distance.

7. The printer step correction method based on visual recognition according to claim 1, 2, or 4, characterized in that: The image acquisition unit is located on the downstream side of the printing platform along the direction of travel of the printing medium.

8. A printer step-by-step correction device based on vision recognition, characterized in that: Used to perform the printer step correction method based on vision recognition as described in any one of claims 1-7; It includes the printing device, the image acquisition unit, and the processor unit.

9. The printer step-by-step correction device based on visual recognition according to claim 8, characterized in that: The image acquisition unit is an industrial camera or a CCD camera.

10. The printer step-by-step correction device based on vision recognition according to claim 8 or 9, characterized in that: The printing medium has standard graphics printed on both sides of the waste edge. There are two image acquisition units, which are respectively set above the printing platform on both sides of the printing medium, and are used to acquire images of the standard graphics on both sides of the waste edge of the printing medium.

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