Battery cell UV jet printing nozzle anomaly detection method

Abstract

The invention discloses a cell UV jet printing nozzle abnormity detection method. The method comprises the following steps: S1, obtaining a test pattern; s2, jet printing a test pattern on the detection paper by a jet printing nozzle; s3, an image acquisition module acquires the pattern printed on the paper; s4, the image recognition module obtains and processes the collected image; s5, judging whether the nozzle is normal or not according to the processed data, if the nozzle is normal, continuing to work, and if the nozzle is abnormal, executing S6; s6, obtaining an abnormal nozzle according to the processed data, and giving an alarm. Based on a machine vision technology, the method comprises the following steps: firstly, editing a test pattern; then collecting a test pattern; and finally, the image identification module carries out algorithm analysis on the test pattern, and judges anomalies such as nozzle hole blocking, inclined spraying, trailing, adhesion and the like. According to the method, the abnormality of the nozzle can be detected before the UV jet printing of the battery cell, the hysteresis quality of judging the state of the nozzle by detecting the appearance defect of the battery cell in the subsequent process is solved, and the material cost of UV ink is saved.

Description

Technical Field

[0001] The invention relates to the field of lithium battery UV inkjet printing, and in particular to a method for detecting abnormalities in a battery cell UV inkjet printing nozzle. Background Art

[0002] In the new energy power battery industry, cell insulation is an important part of battery safety. Currently, cell insulation includes PET blue film, powder coating, UV coating, inkjet printing, etc. Among them, UV inkjet printing (abbreviated as: UV printing) insulation treatment technology has significant advantages in cell surface adhesion, anti-corrosion and consumable loss. Currently, leading power battery companies are testing and applying this insulation process.

[0003] In UV printing technology, the print head is the core component, and factors such as the nozzle status, ink quality, and ambient temperature and humidity will affect the performance of the print head, resulting in abnormalities such as hole blockage, slanted spraying, tailing, and adhesion, which will cause printing defects on the surface of the battery cell, fail to meet insulation requirements, and cause safety risks to the battery cell.

[0004] At present, in the battery cell UV printing production line, the printing quality of the battery cell is judged by manual visual inspection or 3D visual appearance inspection at the end of the battery cell line. This kind of post-process inspection has a lag in the printing operation and cannot promptly feedback abnormalities of the printhead, resulting in waste of UV ink materials. Summary of the invention

[0005] The purpose of the present invention is to provide a method for detecting abnormality of a battery cell UV inkjet printing nozzle, so as to solve the problems raised in the above background technology.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A method for detecting abnormality of a battery cell UV inkjet printing nozzle comprises the following steps:

[0008] S1. Obtain a test pattern;

[0009] S2, the printing head prints a test pattern on the test paper;

[0010] S3, the image acquisition module acquires the pattern printed on the paper;

[0011] S4, the image recognition module obtains the collected image and processes it;

[0012] S5, judging whether the printhead is normal through the processed data, if the printhead is normal, it can continue to work, if the printhead is abnormal, execute S6;

[0013] S6. Obtain abnormal sprinklers based on the processed data and issue an alarm.

[0014] By presetting a test pattern, then the nozzle head acquires the test pattern and performs printing, and detecting the printed pattern can reflect whether the nozzle head is normal, and thus the nozzle head can be quickly detected, avoiding the delay caused by manual detection.

[0015] As a further solution of the present invention: in S1, the test pattern is edited and transmitted to the printing device through the host computer.

[0016] Edit the test pattern for nozzle head abnormality detection in the host computer software of the printing system, without adding additional equipment, reducing the detection cost.

[0017] As a further solution of the present invention: the test pattern is a long line, and the long line at least includes a nozzle position marking line for nozzle hole positioning with a length different from that of other lines, and the remaining long lines are detection lines.

[0018] By setting the test pattern of the long line, the state of the nozzle head can be reflected according to the continuity, length, width, etc. of the printed line. At the same time, by setting a line with a different length as the nozzle hole position marking line, the position of the nozzle head can be positioned through the marking line, and the faulty nozzle head can be accurately detected.

[0019] As a further solution of the present invention: the test pattern also includes nozzle identifiers for identifying the nozzle numbers of the detection lines. The identifiers are identified according to the binary coding method. The lower left grid of the "field" - shaped symbol is the starting position. Filling the lower left corner with black represents 2^0 = 1, which is the corresponding position of nozzle No. 1. Filling the upper left corner with black represents 2^1 = 2, which is the corresponding position of nozzle No. 2. According to the binary coding rule in sequence, the numbers of multiple rows of nozzles can be identified. While positioning the abnormal nozzle hole position through the detection line, the corresponding nozzle numbers can also be quickly positioned.

[0020] As a further solution of the present invention: in S2, first move the nozzle head to the detection mechanism. The detection mechanism includes a printing paper rotation module and an image acquisition module.

[0021] The image acquisition module is on one side of the printing paper rotating device, without affecting the movement of the nozzle head above the printing paper rotating device; the test pattern on the printing paper can move under the action of the rotating shaft to realize the image acquisition of the test pattern.

[0022] As a further solution of the present invention: the image acquisition module includes an industrial camera, a lens, and a combined bar light source.

[0023] The accuracy requirements can be calculated based on the printing width of the nozzle and the number of nozzle holes in a single row, and then an industrial camera that meets the resolution requirements can be selected; based on the field of view size of the test pattern on the printed paper, a lens that meets the focal length requirements can be selected; through combined strip light source for supplementary lighting to enhance the contrast of the test pattern on the printed paper, the lighting angle that meets the requirements can be obtained.

[0024] As a further solution of the present invention: the image processing in S4 includes detection line processing for determining the position of abnormal nozzle holes and nozzle position identifier processing for determining the position of abnormal nozzles.

[0025] As a further solution of the present invention: the detection line processing includes the following steps:

[0026] S4.1. Perform filtering and denoising, binarization processing, and skew correction on the acquired image;

[0027] S4.2. Extract the contour of the trajectory line through Blob analysis and calculate the minimum bounding rectangle.

[0028] By processing the acquired image, extracting the contour of the trajectory line, and then calculating the minimum bounding rectangle according to the contour of the trajectory line.

[0029] As a further solution of the present invention: the nozzle position identifier processing is based on the principle of template matching. Position identifiers are set at fixed intervals on the detection line, and the position numbers of the nozzles are identified through the position identifiers to achieve rapid positioning of abnormal nozzles; different spraying images are used as position identifiers to number the positions of the nozzles, and the position identifiers are in the shape of a "field" character identified by binary coding.

[0030] By setting position identifiers at fixed intervals below the detection line to identify the position numbers of the nozzles, rapid positioning of abnormal nozzles is achieved.

[0031] As a further solution of the present invention: in S5, it is determined whether the trajectory line is continuous according to the length of the minimum bounding rectangle, and whether the nozzle hole is blocked is determined based on whether the trajectory is continuous; according to the pixel spacing between two adjacent trajectory lines, it is judged whether the nozzle hole is spraying obliquely or sticking; according to the width value of the minimum bounding rectangle, it can be judged whether the ink droplet is trailing.

[0032] Based on the detected data, it can be judged whether the nozzle hole is blocked, whether the nozzle hole is spraying obliquely or sticking, and whether there is trailing.

[0033] As a further solution of the present invention: the image acquisition module is connected to the image recognition module through GigE communication, and the image recognition module is respectively connected to the upper computer of the UV printing system and the alarm unit.

[0034] The image acquisition module quickly transmits the acquired image information to the image recognition module through GigE communication, and processes it through the image recognition module. The processed result is transmitted to the upper computer of the UV printing system and the alarm unit.

[0035] Compared with the prior art, the beneficial effects of the present invention are as follows: Based on machine vision technology, first, edit the test pattern in the software interface of the upper computer of the printing system; then, collect the test pattern through the image acquisition module; finally, the image recognition module performs algorithm analysis on the test pattern to determine abnormalities such as nozzle clogging, skew spraying, trailing, and adhesion. This method can detect nozzle abnormalities before UV printing of the battery cell, solve the lag in judging the nozzle state by detecting the appearance defects of the battery cell in the subsequent process, and save the material cost of UV ink. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a schematic diagram of a test pattern for detecting abnormalities of the UV printing nozzle of the battery cell provided by an embodiment of the present invention.

[0037] Figure 2 It is a flowchart of a method for detecting abnormalities of the UV printing nozzle of the battery cell provided by an embodiment of the present invention.

[0038] Figure 3 It is a structural diagram of a system for detecting abnormalities of the UV printing nozzle of the battery cell provided by an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0039] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0040] Please refer to Figure 1-3 , in an embodiment of the present invention, a method for detecting abnormalities of the UV printing nozzle of a battery cell includes the following steps:

[0041] S1. Obtain a test pattern, edit the test pattern and transmit the test pattern to the printing device through the upper computer. Edit the test pattern for detecting nozzle abnormalities in the software of the upper computer of the printing system, without adding additional equipment, reducing the detection cost. The test pattern is a long line, and the long line at least includes a nozzle position marking line for nozzle positioning that is different in length from other lines, and the remaining long lines are detection lines. In addition, the test pattern also includes a nozzle identifier for identifying the nozzle number of the detection line, and the "field" - shaped identifier is encoded in binary.

[0042] In this embodiment, the printing nozzle generally consists of multiple rows of nozzles, and each row of nozzles is composed of a certain number of spray holes. There are differences in the number of spray holes of nozzles from different manufacturers.

[0043] As Figure 1 shown is a printing nozzle with 4 rows of nozzles. Among them, the inkjet trajectory lines of each row of nozzles are parallel detection lines, and the detection lines are arranged according to a certain length and interval. Specifically, 5 detection lines form a group, 4 detection lines have the same length, and the 5th detection line extends beyond the others by a certain length for positioning the spray holes. The 5th line can be quickly located and counted through visual processing means. By comparing with the starting position of the detection line, the position number of the current spray hole can be calculated. Through the detection line design as Figure 1 shown, the position of the abnormal spray hole can be quickly located. As Figure 1 shown, the nozzle identifier is used to identify the nozzle serial number of the detection line. The identifier is identified according to the binary coding method. The lower left grid of the "field" - shaped symbol is the starting position. Filling the lower left corner with black represents 2^0 = 1, which is the corresponding position of nozzle No. 1. Filling the upper left corner with black represents 2^1 = 2, which is the corresponding position of nozzle No. 2. According to the binary coding rule in sequence, the serial numbers of multiple rows of nozzles can be identified. While locating the position of the abnormal spray hole through the detection line, the corresponding nozzle serial number can also be quickly located.

[0044] S2. The printing nozzle sprays a test pattern on the detection paper. In this embodiment, the nozzle is moved to the detection mechanism. The detection mechanism includes a printing paper rotation module and an image acquisition module. The image acquisition module is on one side of the printing paper rotating device and does not affect the movement of the nozzle above the printing paper rotating device; the test pattern on the printing paper can move under the action of the rotating shaft to realize the image acquisition of the test pattern. After each spraying, the detection paper will be moved under the image acquisition module through the rotating mechanism to realize the acquisition of the test pattern, and a blank area is left on the other side of the printing paper to wait for the next spraying.

[0045] S3. The image acquisition module acquires the pattern sprayed on the paper. The image acquisition module includes an industrial camera, a lens, and a combined strip light source. The accuracy requirement can be calculated through the parameters of the printing width of the nozzle and the number of spray holes in a single row, and then an industrial camera that meets the resolution requirement can be selected; through the field - of - view size of the test pattern on the printing paper, a lens that meets the focal - length requirement can be selected; by using the combined strip light source for supplementary lighting to enhance the contrast of the test pattern on the printing paper, the lighting angle that meets the requirements can be obtained.

[0046] S4. The image recognition module acquires and processes the captured images. The image acquisition module is connected to the image recognition module through GigE communication. The image recognition module is respectively connected to the upper computer of the UV inkjet printing system and the alarm unit. The image acquisition module quickly transmits the acquired image information to the image recognition module through GigE communication and processes it through the image recognition module. The processed results are transmitted to the upper computer of the UV inkjet printing system and the alarm unit. Image processing includes detection line processing and nozzle position identifier processing.

[0047] The detection line processing includes the following steps:

[0048] S4.1. Perform filtering and denoising, binarization processing, and skew correction on the acquired images;

[0049] S4.2. Implement the contour extraction of the trajectory line through blob analysis and calculate the minimum bounding rectangle.

[0050] By processing the acquired images, extract the contour of the trajectory line, and then calculate the minimum bounding rectangle according to the trajectory line contour.

[0051] The nozzle position identifier processing is based on the template matching principle. Position identifiers are set at fixed intervals on the detection line. The position numbers of the nozzles are identified through the position identifiers to achieve the rapid positioning of abnormal nozzles; different spraying images are used as position identifiers to number the positions of the nozzles. The position identifiers are in the shape of a "field" character identified by binary coding.

[0052] S5. Judge whether the nozzle is normal based on the processed data. If the nozzle is normal, it can continue to work. If the nozzle is abnormal, execute S6;

[0053] Judge whether the trajectory line is continuous according to the length of the minimum bounding rectangle, and judge whether the spray holes are blocked based on whether the trajectory is continuous; judge whether the spray holes are misaligned or adhered according to the pixel spacing between two adjacent trajectory lines; judge whether the ink drops are trailing based on the width value of the minimum bounding rectangle.

[0054] S6. Obtain the abnormal nozzle based on the processed data and issue an alarm.

[0055] If the image recognition module detects normally, the software interface prompts that the inkjet printing system can perform inkjet printing operations. If the detection is abnormal, the alarm module displays the abnormal type of the nozzle and the corresponding nozzle and spray hole positions. This method can detect the nozzle state before the UV inkjet printing of the battery cell, solve the lag in judging the nozzle state by the appearance defect detection of the battery cell in the subsequent process, and save the material cost of UV ink.

[0056] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0057] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A method for detecting abnormality of a battery cell UV inkjet printing head, characterized in that: It includes the following steps: S1. Obtain a test pattern; S2. The inkjet printhead jets the test pattern on the detection paper; S3. The image acquisition module acquires the pattern jetted on the paper; S4. The image recognition module obtains the acquired image and processes it; S5. Determine whether the printhead is normal based on the processed data. If the printhead is normal, it can continue to work. If the printhead is abnormal, execute S6; S6. Obtain the abnormal printhead according to the processed data and issue an alarm.

2. The method for detecting abnormality of a battery cell UV inkjet printing head according to claim 1, characterized in that: In S1, the test pattern is edited and transmitted to the inkjet device through the host computer.

3. The method for detecting abnormality of a battery cell UV inkjet printing head according to claim 1, characterized in that: The test pattern is a long line, and the long line at least includes a nozzle position marking line for nozzle positioning with a length different from that of other lines, and the remaining long lines are detection lines.

4. The method for detecting abnormality of a battery cell UV inkjet printing head according to claim 1, characterized in that: In S2, first move the printhead to the detection mechanism, and the detection mechanism includes a printing paper rotation module and an image acquisition module.

5. The method for detecting abnormality of a battery cell UV inkjet printing head according to claim 1, characterized in that: The image acquisition module includes an industrial camera, a lens, and a combined bar light source.

6. The method for detecting abnormality of a battery cell UV inkjet printing head according to claim 3, characterized in that: The image processing in S4 includes detection line processing for determining the position of abnormal nozzles and nozzle position identifier processing for determining the position of abnormal nozzles.

7. A method for detecting abnormality of a battery cell UV inkjet printing head according to claim 6, characterized in that: The detection line processing includes the following steps: S4.

1. Perform filtering and denoising, binarization processing, and skew correction on the acquired image; S4.

2. Extract the contour of the trajectory line through Blob analysis and calculate the minimum circumscribed rectangle.

8. The method for detecting abnormality of a battery cell UV inkjet printing head according to claim 6, characterized in that: The nozzle position identifier processing is based on the template matching principle. Position identifiers are set at fixed intervals of the detection line, and the position numbers of the nozzles are identified through the position identifiers to achieve rapid positioning of abnormal nozzles; different spraying images are used as position identifiers to number the positions of the nozzles, and the position identifiers are in the shape of a "field" character identified by binary coding.

9. The method for detecting abnormality of a battery cell UV inkjet printing head according to claim 7, characterized in that: In S5, it is determined whether the trajectory line is continuous according to the length of the minimum circumscribed rectangle, and whether the nozzle is blocked is determined by whether the trajectory is continuous; according to the pixel spacing between two adjacent trajectory lines, it is judged whether the nozzle is squirting obliquely or sticking; according to the width value of the minimum circumscribed rectangle, it can be judged whether the ink droplet is trailing.

10. The method for detecting abnormality of a battery cell UV inkjet printing head according to claim 1, characterized in that: The image acquisition module is connected to the image recognition module through GigE communication, and the image recognition module is respectively connected to the host computer of the UV inkjet system and the alarm unit.

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