A portable printer testing method

Abstract

This invention proposes a portable printer testing method, comprising the following steps: S1, preparing the original print content; S2, printing the prepared original print content one by one onto the same sheet of paper for original print testing, and evaluating the quality of each print, wherein the original print content is not overlapped when printed multiple times on the same sheet; S3, adjusting the original print content to obtain superimposed print content; S4, superimposed print testing, printing the obtained superimposed print content one by one onto the sheet that underwent the original print test, and evaluating the quality of each superimposed print; S5, changing the paper and repeating steps S2 and S4 until the printer print count test is completed. This portable printer testing method effectively saves the amount of paper used during testing by reusing the printing paper multiple times, reducing testing costs and consumable consumption.

Description

Technical Field

[0001] This invention relates to the field of printer technology, and more particularly to a method for testing portable printers. Background Technology

[0002] Before electronic products are released to the market, they need to undergo various tests to maximize the evaluation and discovery of whether the product's functions are complete, whether its performance meets the standards, whether its safety meets the intended use scenarios, and whether its stability and durability meet user needs. This is especially true for printers, which require extensive testing before finalization. Among these tests, durability and stability require stress testing, which assesses whether the printer's performance degrades through prolonged, uninterrupted, repeated printing.

[0003] The patent application CN114226284A, entitled "An Automatic Test Line for a Printer and Its Test Method," discloses an automatic test line for printers. The test line is used to perform various performance tests on the printer. In actual testing, portable printers need to undergo hundreds of thousands of A4-size printing pressure tests after development. If all hundreds of thousands of prints are done using new A4 paper, it will result in a large consumption of A4 paper. This will not only increase testing costs but also undermine my country's advocacy of saving paper and protecting forest resources. Summary of the Invention

[0004] In view of this, the present invention proposes a portable printer testing method that, by performing original printing tests and superimposed printing tests, reuses a single sheet of paper for multiple printing tests, effectively saving the cost required for testing.

[0005] The technical solution of this invention is implemented as follows: This invention provides a portable printer testing method, comprising the following steps:

[0006] S1. Organize the original printed content;

[0007] S2. Print the original printed content one by one onto the same sheet of paper for original printing test, and evaluate the quality of each printed content. The original printed content should not overlap when printed multiple times on the same sheet of paper.

[0008] S3. Adjust the original print content to obtain the superimposed print content;

[0009] S4. Overlay printing test: Print the obtained overlay printing content one by one onto the paper that has undergone the original printing test, and evaluate the quality of each overlay printing content.

[0010] S5. Change the paper and repeat steps S2 and S4 until the printer print count test is completed.

[0011] Based on the above technical solutions, preferably, step S1 includes the following sub-steps:

[0012] S11. Use image processing software to define a working area that is the same size as the paper used for testing;

[0013] S12. Add several layers to the working area, and the size of each layer is the same as the size of the working area;

[0014] S13. Place the content to be printed into each layer, and ensure that there is no overlap when the layers are stacked. The collection of the layers is the original printing content, and each layer corresponds to one printing action.

[0015] More preferably, the printed content placed in each layer includes text, graphics and images, and the printed content is evenly distributed in each layer.

[0016] Based on the above technical solution, preferably, step S2, the quality assessment of the content printed in the original print test includes the following steps:

[0017] S21. Scan the paper to obtain the current image;

[0018] S22. Overlay and merge the original printed content previously printed on the paper with the original printed content printed this time to obtain a comparison image;

[0019] S23. Set the SSIM_RGB threshold and compare the current image with the comparison image using the SSIM_RGB algorithm. If the obtained SSIM_RGB value is higher than the SSIM_RGB threshold, the printing effect is good.

[0020] More preferably, the SSIM_RGB algorithm in step S23 is:

[0021]

[0022] Where SSIM represents structural similarity, x and y are the grayscale images of the two images to be compared, and μ x μ is the average gray value of x. y It is the average gray value of y. It is the gray variance of x. σ is the gray variance of y. xy It is the gray covariance of x and y, and c1 and c2 are constants used to maintain stability;

[0023]

[0024] Among them, V RGBR1 and R2 represent the R component values ​​of the two images being compared, G1 and G2 represent the G component values, and B1 and B2 represent the B component values.

[0025] SSIM_RGB = SSIM + (1 - V) RGB )

[0026] The value of SSIM ranges from 0 to 1 and from 1 to V. RGB The value range is also 0-1, therefore the value range of SSIM_RGB is 0-2.

[0027] Based on the above technical solutions, preferably, the adjustment of the original printed content in step S3 includes at least one of improving the grayscale value or replacing the color of the original printed content.

[0028] In a further preferred embodiment, step S4, which involves evaluating the quality of the printed content of the overlay printing test, is the same as the step of evaluating the quality of the printed content of the original printing test.

[0029] Based on the above technical solutions, preferably, in step S5, the paper replacement includes normal replacement and abnormal replacement. If step S4 is completed, normal replacement is performed.

[0030] More preferably, the print quality evaluation results in steps S2 and S4 are divided into qualified and unqualified. If the evaluation result is unqualified, abnormal paper replacement is performed. The abnormal replacement includes the following steps:

[0031] S51. If the print quality assessment in step S2 or step S4 is unsatisfactory, replace the paper and restart step S2.

[0032] S52. Set up backup printing content. If the printing quality assessment in step S2 or step S4 is still unqualified after step S51, the paper is replaced again and the backup printing content is used for printing test.

[0033] S53. If, after performing step S52, a print quality assessment in step S2 or step S4 is still deemed unqualified, feedback will be sent to the tester.

[0034] More preferably, the SSIM_RGB threshold for the single print content quality assessment of the original print test is greater than the SSIM_RGB threshold for the single print content quality assessment of the superimposed print test.

[0035] The portable printer testing method of the present invention has the following advantages over the prior art:

[0036] (1) By conducting the original printing test and adjusting the original printing content, an overlay printing test can be performed after the original printing test, so that multiple printings can be performed on a single sheet of paper, allowing the paper to be reused multiple times, effectively saving the number of sheets of paper during testing, and reducing testing costs and material consumption; (2) The printing content is divided into different layers that do not overlap, and each layer is printed sequentially during the printing test. Combining the original printing test and the overlay printing test, the number of sheets of paper during testing is further saved, reducing testing costs and material consumption.

[0037] (3) During the original printing test and the superimposed printing test, the printed image is evaluated by an algorithm to determine whether the paper needs to be replaced in advance, and the test is corrected in time to avoid unnecessary waste of paper caused by continuous printing.

[0038] (4) Replace the paper after the first failure of the print test, replace the paper after the second failure and use the spare print content. Feedback is given after the third failure. This can avoid inaccurate test results due to paper or print content problems, avoid unnecessary information feedback, and reduce the labor cost of troubleshooting. Attached Figure Description

[0039] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0040] Figure 1 This is a schematic diagram illustrating the steps of the portable printer testing method of the present invention. Detailed Implementation

[0041] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0042] like Figure 1 As shown, the portable printer testing method of the present invention mainly uses A4 printing paper for printing tests in this embodiment. The paper, printing paper and test paper mentioned below all refer to A4 printing paper. This method includes steps S1-S5.

[0043] Step S1: Organize the original printed content.

[0044] The printer industry typically uses a 5% page coverage rate to assess consumable lifespan. For example, an inkjet printer cartridge rated for 500 pages of printing life is estimated based on each print covering 5% of the A4 paper. Using this concept, the print content can be cleverly designed to ensure that, during stress testing, the first 20 prints using the same A4 paper do not cover the entire page. This involves steps S11-S13.

[0045] Step S11: Use image processing software to define a working area that is the same size as the paper used for testing.

[0046] In image processing software such as Photoshop, design an A4-sized (210mm in the processing software) work area for subsequent generation of print materials. Design the content to be tested for printing, which should include different categories such as Chinese text, English characters, common graphics, and images.

[0047] Step S12: Add several layers to the working area, and the size of each layer is the same as the size of the working area.

[0048] In this embodiment, 20 new layers are added within the A4 working area of ​​Photoshop, and each layer is A4 size.

[0049] Step S13: Place the content to be printed into each layer, and ensure that there is no overlap when the layers are stacked. The collection of the layers is the original content to be printed, and each layer corresponds to one printing action.

[0050] Place the text, characters, graphics, and images into 20 different layers. Manually adjust the content and position of each layer to ensure that when the 20 layers are superimposed and combined into an A4-sized image, there is no overlap. At the same time, the various text, characters, graphics, and images should be evenly distributed into the 20 layers as much as possible.

[0051] After setting 20 layers, there is still a large amount of empty area in the A4 image that is not covered by text, characters, graphics, or images, resulting in a single layer covering far less than 5% of the image area. In this case, divide the empty area graphics into 20 equal parts and place them into 20 layers respectively. It should be noted that the empty area graphics are not connected to the original text, characters, graphics, or images placed in the layers.

[0052] Each of the 20 layers outputs 20 images, labeled p1, p2, ..., p20. The content coverage of each image is approximately 5%. The set of 20 images output by each of the 20 layers is the original printed content.

[0053] It should be noted that the original printed test images contain both black and white and color content. The black and white content should be selected with a lower grayscale value, and the color content should be selected with a lighter color. This selection is for the preparation of overlay printing tests.

[0054] Step S2: Print the original printed content one by one onto the same sheet of paper for original printing test, and evaluate the quality of each printed content. The original printed content should not overlap when printed multiple times on the same sheet of paper.

[0055] The initial print test is defined as the first 20 print tests on new A4 paper. During this stage, all printed content is not superimposed, meaning that the printed areas on the paper are not repeated. This step requires a scanner for auxiliary testing to scan the paper after each print to form the current image, which is used to evaluate the quality of each print.

[0056] Specifically, the quality assessment of the content printed in the original print test includes steps S21-S23.

[0057] Step S21: Scan the paper to obtain the current image.

[0058] After a single print, the scanner scans the contents of the paper to obtain the current image.

[0059] Step S22: Overlay and merge the original printed content previously printed on the paper with the original printed content printed this time to obtain a comparison image.

[0060] If the scanned content contains only one print test content, that is, after the first print on the A4 paper, then p1 in step S13 above is the comparison image. If the scanned A4 paper contains more than one print content, such as three prints, then the p1, p2, and p3 images output in step S13 are superimposed and merged to generate a new image p123, which is used as the comparison image.

[0061] It should be noted that the current image obtained from scanning (including multiple printouts) can be directly superimposed on the image from step S13 for comparison; alternatively, the previous printouts can be removed from the current image obtained from scanning, leaving only the printouts from the current printout, and then compared and analyzed with the single image from step S13.

[0062] Step S23: Set the SSIM_RGB threshold and compare the current image with the comparison image using the SSIM_RGB algorithm. If the obtained SSIM_RGB value is higher than the SSIM_RGB threshold, the printing effect is good.

[0063] Specifically, the SSIM_RGB algorithm is as follows:

[0064]

[0065] Where SSIM represents structural similarity, x and y are the grayscale images of the two images to be compared, and μ x μ is the average gray value of x. y It is the average gray value of y. It is the gray variance of x. σ is the gray variance of y. xy Let c1 be the gray covariance of x and y, where c1 = (k1L). 2 c2 = (k2L) 2 SSIM is a constant used to maintain stability. L is the dynamic range of pixel values. k1 = 0.01, k2 = 0.03. The range of structural similarity is 0-1. When two images are exactly the same, the value of SSIM is equal to 1.

[0066] Traditional SSIM performs a full-scale comparison of images. This invention adapts the SSIM algorithm by adding arbitrarily selected 10 pixels from both images for local verification. The difference between the RGB values ​​(each component ranging from 0 to 255) of corresponding pixels in the two images is then calculated. The formula for calculating this difference is as follows:

[0067]

[0068] Among them, V RGB R1 and R2 represent the R component values ​​of the two images being compared, G1 and G2 represent the G component values, and B1 and B2 represent the B component values. The sum of the differences is divided by 255 × 3 to achieve normalization. For example, if the pixel values ​​of corresponding points in two images are (120, 30, 75) and (130, 40, 70) respectively, then their V... RGB =0.033.

[0069] The SSIM_RGB algorithm designed in this invention combines the two above, and the formula is as follows:

[0070] SSIM_RGB = SSIM + (1 - V) RGB )

[0071] The value of SSIM ranges from 0 to 1 and from 1 to V. RGB The value range is also 0-1, therefore the value range of SSIM_RGB is 0-2.

[0072] It should be noted that since the value range of SSIM_RGB is 0-2, in this embodiment, the SSIM_RGB threshold can be selected as 1.95.

[0073] During the initial print test, two A4 test sheets can be prepared and labeled as a and b respectively. A4 sheets a and b are printed alternately for testing. When a is printed, b is placed in the scanner to scan the content on the b sheet; similarly, when b is printed, a is scanned. This operation allows the printer to perform the initial print test uninterruptedly, effectively improving the testing efficiency.

[0074] Meanwhile, the initial printing test phase ends after the A4 printing test paper has undergone 20 printing tests.

[0075] Step S3: Adjust the original print content to obtain the superimposed print content.

[0076] Adjusting the original printed content, including at least one of increasing the grayscale value or replacing the color of the original printed content.

[0077] Specifically, for the 20 print content layers prepared in step S13, if the content is in grayscale color space (black and white), the grayscale value of the content is increased, and text, characters, graphics, and images with the same shape, the same position, and higher grayscale value are regenerated. If the content is in RGB space (color), a darker color is selected to cover it.

[0078] Step S4: Overlay printing test. Print the obtained overlay printing content one by one onto the paper that has undergone the original printing test, and evaluate the quality of each overlay printing content.

[0079] The overlay printing test is defined as follows: after the A4 test paper has undergone the initial printing test and the content has filled the A4 paper, the paper is reused to reduce the consumption of pressure test paper. Tests show that the A4 paper after the initial printing can still be used 20 times, provided the pressure test proceeds normally. The overlay printing content obtained in step S3 is the content required for the overlay printing test.

[0080] The steps for quality assessment of the overlay test printouts are similar to those for the original printouts. Specifically, an auxiliary inkjet printer is required. This auxiliary printer should undergo rigorous testing to ensure the printouts are complete and the colors are accurate (or consistent with the colors printed by the portable sheet printer being tested). Using the auxiliary inkjet printer, first print the original test content p1, p2, ..., p20. Then, print the overlay test content p21, p22, ..., p220 on the A4 test paper containing the original test content. Simultaneously, scan the printed test content as images, denoted as pt21, p22, ..., p220. For each image sequence t22,…,pt220, the first two images from pt21,pt22,…,pt220 are merged to generate pc2, the first three images are merged to generate pc3, and so on, until the final merged image sequence pc1,pc2,…,pc20 is obtained, where pc1 is the first image, i.e., pt21. The scan results of each print in the overlay printing test are compared with the images corresponding to the numerical numbers of each print sequence in pc1,pc2,…,pc20 using SSIM_RGB value analysis. If the values ​​are higher than the SSIM_RGB threshold, it indicates that the test result of this overlay printing test is qualified.

[0081] In addition to the methods mentioned above, the printed content can also be directly overlaid onto the image formed by combining 20 layers of the original printed content, with each overlay corresponding to a comparison image.

[0082] However, since overlay printing tests require covering the original print with a new layer of printed content, the SSIM_RGB threshold for overlay printing test evaluation can be appropriately reduced. In other words, the SSIM_RGB threshold for evaluating the quality of a single print in the original print test should preferably be greater than the SSIM_RGB threshold for evaluating the quality of a single print in the overlay printing test. Specifically, in this embodiment, the SSIM_RGB threshold for overlay printing test evaluation can be selected as 1.90.

[0083] Step S5: Change the paper and repeat steps S2 and S4 until the printer print count test is completed.

[0084] In this step, paper replacement includes normal replacement and abnormal replacement. If steps S2 and S4 are completed, normal replacement is performed; otherwise, paper replacement is required in advance. That is, after the original print test and the overlay print test, the paper can be replaced normally after 40 prints. If the paper falls below the SSIM_RGB threshold during the printing process, it needs to be replaced in advance. Regardless of whether the paper is replaced normally or not, if the printer completes the required number of prints, the test is considered complete.

[0085] Specifically, the print quality evaluation results in steps S2 and S4 are divided into qualified and unqualified. If the print quality is lower than the corresponding SSIM_RGB threshold in the corresponding print test step, the evaluation result is unqualified and abnormal paper replacement is required. The abnormal replacement includes steps S51-S53.

[0086] Step S51: If the print quality assessment in either step S2 or step S4 is unsatisfactory, replace the paper and restart step S2.

[0087] If the print quality is deemed unacceptable during the print test, replace the paper and repeat the original print test.

[0088] Step S52: Set up backup printing content. If the print quality assessment in step S2 or step S4 is still unqualified after step S51, change the paper again and use the backup printing content for printing test.

[0089] If the first print test fails, the paper should be replaced and the print test repeated. If the second print test fails, the paper should be replaced and a print test should be performed using spare print content. Spare print content includes new original print content and new overlaid print content. For specific steps on preparing spare print content, please refer to step S1.

[0090] In this embodiment, step S51 is the second printing test after the first failure.

[0091] Step S53: If, after performing step S52, a print quality assessment in step S2 or step S4 is still deemed unqualified, feedback is sent to the tester.

[0092] If any issues persist during the original print test and overlay print test using the spare print content, the issue needs to be reported to the tester for inspection and troubleshooting.

[0093] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method of testing a portable printer, characterized by, The method comprises the following steps: S1, arranging original printing content; The step S1 comprises the following sub-steps: S11, defining a working area with the same size as the paper used for testing by using picture processing software; S12, adding several layers in the working area, and the size of each layer is the same as the working area; S13, putting the printing content to be printed into each layer respectively, and ensuring that there is no overlap when each layer is superimposed, and the obtained set of each layer is the original printing content, and each layer corresponds to a printing action; S2, printing the arranged original printing content on the same paper one by one by the printer to perform original printing test, and performing quality evaluation on the content printed each time, wherein the original printing content is printed multiple times on the same paper without overlapping; S3, adjusting the original printing content to obtain superimposed printing content; S4, superimposed printing test, printing the obtained superimposed printing content on the paper that has undergone original printing test one by one by the printer, and performing quality evaluation on the content printed each time; S5, replacing the paper and repeating steps S2 and S4 until the printer printing test is completed; In step S2, the quality evaluation on the content printed each time in the original printing test comprises the following steps: S21, scanning the paper to obtain a current image; S22, superimposing and merging the original printing content printed on the paper before and the original printing content printed this time to obtain a comparison image; S23, setting an SSIM_RGB threshold value, and comparing the current image with the comparison image by using SSIM_RGB algorithm, if the obtained SSIM_RGB value is higher than the SSIM_RGB threshold value, the printing effect is good; The SSIM_RGB algorithm in step S23 is: where SSIM is the structural similarity, x and y are the gray images of two images to be compared, μ x is the average value of the gray scale of x, μ y is the average value of the gray scale of y, is the variance of the gray scale of x, is the variance of the gray scale of y, σ xy is the covariance of the gray scale of x and y, and c1 and c2 are constants for maintaining stability. where V RGB is the difference of RGB, R1 and R2 represent the R component values of the two images, G1 and G2 are the G component values, and B1 and B2 are the B component values; SSIM RGB = SSIM + (1 - V RGB ) wherein SSIM has a value ranging from 0 to 1, 1-V RGB The value range is also 0-1, and the value range of SSIM_RGB is 0-2.

2. The portable printer testing method of claim 1, wherein, The printing content put into each layer includes text and images, and the printing content is uniformly distributed in each layer.

3. The portable printer testing method of claim 1, wherein, In step S3, the adjustment of the original printing content comprises at least one of the following: increasing the gray value of the original printing content or replacing the color of the original printing content.

4. The portable printer testing method of claim 1, wherein, In step S4, the quality evaluation on the content printed each time in the superimposed printing test is the same as the quality evaluation on the content printed each time in the original printing test.

5. The portable printer testing method of claim 1, wherein, In step S5, the replacement of the paper includes normal replacement and abnormal replacement, if step S4 is completed, the normal replacement is performed.

6. The portable printer testing method of claim 5, wherein, The printing quality evaluation results in steps S2 and S4 are divided into qualified and unqualified, if the evaluation result is unqualified, the abnormal replacement of the paper is performed, and the abnormal replacement comprises the following steps: S51, if the printing quality evaluation in step S2 or step S4 is unqualified, the paper is replaced and step S2 is restarted; S52, setting backup printing content, if the printing quality evaluation in step S2 or step S4 is still unqualified after step S51 is performed, the paper is replaced again, and the backup printing content is used for printing test; S53, if the printing quality evaluation in step S2 or step S4 is still unqualified after step S52 is performed, the feedback is given to the tester.

7. The portable printer testing method of claim 4, wherein, The SSIM RGB threshold of the original print test single-print content quality assessment is greater than the SSIM RGB threshold of the superimposed print test single-print content quality assessment.

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