Printer stepping deviation correction method and device based on visual identification

Abstract

The invention provides a printer stepping deviation correction method and device based on visual identification, the device 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 graph with a standard size is printed under two steps; the image acquisition unit is mounted in a printing platform area of printing equipment and is used for acquiring a standard graph printed on the surface of a printing medium at a printing platform and sending the standard graph to the processor unit; the processor unit is used for acquiring image information of the standard graph and identifying actual size data of the standard graph; and the processor unit compares the difference between the actual size data of the standard graph and the standard size data set by the program in the advancing direction of the printing medium, and adjusts the stepping value of the printing equipment according to the difference. According to the method, the printing pattern deformation caused by the extension deformation of the printing medium in the printing process can be corrected, and the printing quality is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of printers, and in particular to a method and device for correcting printer stepping errors based on visual recognition. Background Art

[0002] Inkjet printers are the most common printing devices in the advertising industry. With the development of technology, related technologies are constantly developing and improving.

[0003] In terms of printing efficiency, inkjet printers have developed into a large range of high-speed printers. The reciprocating speed of the printing carriage has been continuously improved, and the printing efficiency has also been continuously improved.

[0004] In terms of printing materials, for paper, the thickness of the material is getting thinner and thinner, and the properties are becoming more sensitive. The inside and outside of the same roll of material may have different ductility.

[0005] In addition, printing materials are constantly developing, such as paper, cloth, silk, UV film, etc.

[0006] Finally, people have higher and higher requirements for printing accuracy, requiring the printed images to be more exquisite and the colors to be richer.

[0007] The impact of these factors not only brings challenges to the hardware configuration of printing equipment, but also requires adjustments in printing technology.

[0008] Among them, as the printing material mentioned above, as the thickness of the roll material becomes thicker, the ductility of the inner and outer roll parts of the same material is different, resulting in inconsistent front and back stretching of the same roll material during the printing process, which ultimately affects the printing quality.

[0009] Currently, the step correction of the printer can only be set according to the known offset. This process mainly relies on manual intervention and requires professionals to continuously adjust and correct the step rhythm of the printer during the printing process. This is not only inconvenient, but also places high demands on the professional quality of the workers.

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

[0011] The purpose of the present invention is to address the deficiencies in the prior art and to provide a method and device for printer step correction based on visual recognition for correcting the step setting value for the printed image deformation problem caused by the stretching deformation of the printing medium, thereby ultimately making the step setting value adapt to the deformation amount of the printing medium, thereby improving the printing quality.

[0012] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a printer step correction method based on visual recognition, including a printing device, an image acquisition unit and a processor unit, which is executed by the following method: When the printing device prints on the print medium in the print platform area, a standard graphic with a standard size is printed on the surface of the print 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, and the first part and the second part are spliced ​​to form the standard graphic; The image acquisition unit is installed in the printing platform area of ​​the printing device to acquire the standard graphics printed on the surface of the printing medium at the printing platform and send it to the processor unit; The processor unit acquires image information of the standard graphic and identifies 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 traveling direction of the printing medium, and adjusts the step value of the printing device according to the difference.

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

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

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

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

[0017] Based on the above, within one stepping distance, the second part of the previous standard graphic and the first part of the next standard graphic are printed.

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

[0019] A printer stepping correction device based on visual recognition, used to execute the printer stepping correction method based on visual recognition; It comprises the printing device, an image acquisition unit and a 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 the waste edges on both sides of the printing medium respectively, and two image acquisition units are provided, which are respectively arranged above the printing platforms on both sides of the printing medium for respectively acquiring images of the standard graphics on the waste edges on both sides of the printing medium.

[0022] The present invention has outstanding substantive features and significant progress compared to the prior art. Specifically, the present invention has the following advantages: When the printing medium has different degrees of extension and deformation due to different humidity levels of the inner and outer rolls, the original step setting value will not match the deformed printing medium, causing deformation of the printed graphics. The present invention prints a standard graphic on the surface of the printing medium while printing the graphics. This standard graphic is completed by splicing the printing jobs under two stepping actions, and then reads the graphic through image recognition to identify the graphic size, and then compares it with the set size of the standard graphic. If there is a difference, it indicates that the printed standard graphic is deformed, which further indicates that the printing medium has undergone tensile deformation and the step setting value has deviated. The step setting value is adjusted according to the difference to eliminate the difference. The dynamic and automatic execution of this process can ensure that the step setting value is always compatible with the deformation of the printing medium, thereby ultimately ensuring the printing effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a principle diagram of the printer step correction method based on visual recognition in the present invention.

[0024] Figure 2 It is a standard graphical schematic diagram after tensile deformation growth in the present invention.

[0025] Figure 3 It is a schematic diagram of a standard figure after the stretching deformation and shortening in the present invention.

[0026] In the figure: 1. Image acquisition unit; 2. Printing platform; 3. Printing medium; 4. Standard graphics; 5. Processor unit. DETAILED DESCRIPTION

[0027] The technical solution of the present invention is further described in detail below through specific implementation methods.

[0028] Example 1 like Figure 1-Figure 3 As shown, a printer step correction method based on visual recognition includes a printing device, an image acquisition unit 1 and a processor unit, and is performed by the following method: When the printing device prints on the printing medium 3 in the area of ​​the printing platform 2, a standard graphic 4 with a standard size is printed 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 ​​to form the standard graphic.

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

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

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

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

[0033] The processor unit 5 acquires image information of the standard graphic 4 and identifies 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 traveling direction of the printing medium, and adjusts the step value of the printing device according to the difference.

[0035] Technical principle description: Take a roll of thin printing paper stored in a relatively humid environment as an example. During the storage process, due to the influence of environmental humidity, the outer roll of the paper will be more humid than the inner roll. During the printing process, since the printing medium needs to be tensioned to ensure flatness, it will deform to a certain extent. Paper with high humidity will deform more than paper with low humidity. This is the premise.

[0036] After paper loading is completed and printing begins, the print medium is stretched and flattened. When passing through the print platform, the print carriage prints a standard graphic, i.e., a square, on the waste edge area of ​​the print medium.

[0037] However, due to the irregular problem that the printing medium has large external deformation and small internal deformation, the printed square will have shorter sides as the deformation of the printing medium decreases, which will be different from the size of the standard graphic. Figure 3 shown.

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

[0039] By comparing the actual size with the standard size set in the program, it is found that the length of the graphic side along the stepping direction is shortened. Then the stepping setting value of the printing device is adjusted and the stepping setting value is reduced synchronously to compensate 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 the situation where the humidity of the outer roll is low and the humidity of the inner roll is high, such as Figure 2 As shown, the step setting value can also be changed from small to large synchronously.

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

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

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

[0044] Example 2 A printer stepping correction device based on visual recognition, used to execute the printer stepping correction method based on visual recognition; It comprises the printing device, an image acquisition unit and a 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 on both sides of the printing medium, and two image acquisition units are provided, which are respectively arranged above the printing platforms on both sides of the printing medium to respectively acquire images of the standard graphics on the waste edges on both sides of the printing medium.

[0046] In this embodiment, the deformation conditions on both sides may be different, indicating that the printing medium itself is offset. At this time, the printing medium itself needs to be corrected. The correction process needs to be notified manually, so an alarm can usually be connected.

[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or some technical features can be replaced by equivalents without departing from the spirit of the technical solution of the present invention, which should be included in the scope of the technical solution for protection of the present invention.

Claims

1. A printer step correction method based on visual recognition, characterized in that: The method comprises a printing device, an image acquisition unit and a processor unit, and is executed by the following method: When the printing device prints on the print medium in the print platform area, a standard graphic with a standard size is printed on the surface of the print 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, and the first part and the second part are spliced ​​to form the standard graphic; The image acquisition unit is installed in the printing platform area of ​​the printing device to acquire the standard graphics printed on the surface of the printing medium at the printing platform and send it to the processor unit; The processor unit acquires image information of the standard graphic and identifies 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 traveling direction of 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 printing position of the standard graphic is located 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 pattern is a pattern having a length dimension in the traveling direction of the printing medium.

4. The printer step correction method based on visual recognition according to claim 3 is characterized in that: The standard pattern is a square or a rectangle or a line segment extending along the traveling direction of the printing medium or two points at a fixed interval along the traveling direction 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 dimension of the standard pattern along the traveling direction of 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: Within one stepping distance, print the second part of the previous standard graphic and the first part of the next standard graphic.

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

8. A printer step correction device based on visual recognition, characterized in that: Used to execute the printer step correction method based on visual recognition as described in any one of claims 1 to 7; It comprises the printing device, an image acquisition unit and a processor unit.

9. The printer stepping 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 stepping correction device based on visual recognition according to claim 8 or 9, characterized in that: Standard graphics are printed on the waste edges on both sides of the printing medium. Two image acquisition units are provided, which are respectively arranged above the printing platforms on both sides of the printing medium to respectively acquire images of the standard graphics on the waste edges on both sides of the printing medium.

Images