Method for positioning abnormal spray hole in pixel pit printing and ink-jet printer

Abstract

The invention relates to the technical field of ink-jet printing of display screens, in particular to a method for positioning abnormal spray holes in pixel pit printing and an ink-jet printer, and the method comprises the steps that multiple sub-pixel pit images with the same ink droplet defect type on a substrate are acquired, and the ink droplet defect type comprises an ink droplet satellite droplet defect and an ink droplet bridging defect; a plurality of printing spray hole groups corresponding to the plurality of sub-pixel pits are obtained, one sub-pixel pit corresponds to one printing spray hole group, and one printing spray hole group comprises a plurality of spray holes; and if the first spraying holes exist in the multiple printing spraying hole sets, it is determined that the first spraying holes are abnormal spraying holes. According to the method and the device, the abnormal spray hole corresponding to the ink droplet defect of the sub-pixel pit can be positioned.

Description

A method for locating abnormal nozzles in pixel pit printing and an inkjet printer Technical Field

[0001] This application relates to the field of inkjet printing technology for displays, specifically to a method for locating abnormal nozzles in pixel pit printing and an inkjet printer. Background Technology

[0002] Currently, inkjet printing on displays requires print planning (matching the nozzles in the printhead module with the droplets in the pixel pits). This matching process involves filtering the nozzles in the printhead module, which disables some nozzles (i.e., those nozzles whose ink droplet volume, speed, etc., do not meet the requirements) and uses the undisabled nozzles (also known as valid nozzles) for print planning.

[0003] However, due to the instability of nozzles during long-term printing, printing defects (such as satellite drops and droplet bridging) can still exist in sub-pixel pits after print planning. Furthermore, since multiple droplet landing points are often set within sub-pixel pits (e.g., R sub-pixel pits), these droplet landing points are often matched by multiple nozzles. This means that after droplet fusion, it's impossible to directly locate the matching nozzle from the printing defects within the sub-pixel pit. Directly disabling all nozzle groups corresponding to sub-pixel pits with printing defects would result in a large number of disabled nozzles, potentially increasing the number of print passes and reducing printing efficiency.

[0004] Therefore, for the positioning of abnormal nozzles in pixel pit printing, a method for locating abnormal nozzles in pixel pit printing and an inkjet printer are needed. Summary of the Invention

[0005] This application provides a method for locating abnormal nozzles in pixel pit printing and an inkjet printer. This application can locate abnormal nozzles corresponding to ink droplet defects in sub-pixel pits.

[0006] The first aspect of this application discloses a method for locating abnormal nozzles in pixel pit printing. The method includes: acquiring images of multiple sub-pixel pits on a substrate that have the same type of ink droplet defect, the ink droplet defect type including ink droplet satellite defects and ink droplet bridging defects; acquiring multiple printing nozzle groups corresponding to the multiple sub-pixel pits, one sub-pixel pit corresponding to one printing nozzle group, and one printing nozzle group including multiple nozzles; if a first nozzle is present in all of the multiple printing nozzle groups, then the first nozzle is confirmed as an abnormal nozzle.

[0007] In the above scheme, multiple printing nozzle groups corresponding to multiple sub-pixel pits of the same ink droplet defect type are used. If these printing nozzle groups have a common nozzle, that nozzle is likely an abnormal nozzle. Since the defects caused by ink droplets ejected from the abnormal nozzle are generally of the same type after the nozzle becomes abnormal, and there is a one-to-one correspondence between sub-pixel pits and printing nozzle groups, which is determined in the printing planning stage before inkjet printing, the abnormal nozzle in a sub-pixel pit can be cross-identified using the above method.

[0008] In one possible implementation, the plurality of sub-pixel pits include a first sub-pixel pit, which corresponds to a first print nozzle group; the first print nozzle group further includes a second nozzle, which is any nozzle in the first print nozzle group other than the first nozzle; the positioning method further includes: replacing the second nozzle in the first print nozzle group with a backup nozzle to obtain a backup nozzle group; the backup nozzle is a backup nozzle of the second nozzle; performing test printing with the backup nozzle group and obtaining a test print sub-pixel pit image after printing; determining whether there is an ink droplet defect in the first sub-pixel pit in the test print sub-pixel pit image; if there is an ink droplet defect in the first sub-pixel pit in the test print sub-pixel pit image, then determining that the second nozzle is a normal nozzle; if there is no ink droplet defect in the first sub-pixel pit in the test print sub-pixel pit image, then determining that the second nozzle is an abnormal nozzle.

[0009] In the above scheme, for any abnormal nozzles that may exist in the subpixel pits but have not yet been located, test printing is performed by replacing them with backup nozzles. The abnormal nozzles are then located based on the test print results. During this process, each nozzle to be tested (the backup nozzle is a backup of the nozzle to be tested) is replaced with a backup nozzle one by one, and then the abnormal nozzles are located based on the test print results. This method can screen all the nozzles to be tested in the subpixel pits.

[0010] In one possible implementation, when the ink droplet defect type is an ink droplet satellite droplet defect, the positioning method further includes: if the first quantity is less than the second quantity, and the first quantity is not 0, then the second nozzle is confirmed to be an abnormal nozzle; wherein, the first quantity is the number of satellite drops in the test printed sub-pixel pit image, and the second quantity is the number of satellite drops in the first sub-pixel pit.

[0011] The above solution discloses a test print where ink droplet defects exist in the sub-pixel pit image, but these defects differ from those in the first sub-pixel pit. This situation requires a separate discussion of the ink droplet defect type; different types of ink droplet defects result in different defects. In the case of ink droplet satellite defects, the number of ink droplet satellites can be used as a criterion to determine whether the second nozzle is an abnormal nozzle.

[0012] In one possible implementation, when the droplet defect type is a droplet bridging defect, the positioning method further includes: if the first span is less than the second span, and the first span is not 0, then the second nozzle is confirmed to be an abnormal nozzle; wherein, the first span is the span of the bridging droplet area in the test printed sub-pixel pit image in the X-axis direction or the Y-axis direction, the second span is the span of the bridging droplet area in the first sub-pixel pit in the X-axis direction or the Y-axis direction, and both the first span and the second span are spans in the X-axis direction or both are spans in the Y-axis direction.

[0013] In the above scheme, when dealing with ink droplet bridging defects, the span of the bridging ink droplet area in the test printed sub-pixel pit image is judged to determine whether the second nozzle is an abnormal nozzle. Selecting the span of the bridging ink droplet area allows for a qualitative assessment of the effect after the nozzle ejects ink droplets, and the span can be directly obtained through image recognition (e.g., the number of pixels occupied by the ink droplet bridging area in the X-axis or Y-axis direction in the image is used as the span). It should be noted that the comparison between the first span and the second span must be in the same direction (i.e., both in the X-axis direction or both in the Y-axis direction).

[0014] In one possible implementation, when the ink droplet defect type is an ink droplet bridging defect, the positioning method further includes: if the first area is smaller than the second area and the first area is not 0, then the second nozzle is confirmed to be an abnormal nozzle; wherein, the first area is the area of ​​the bridging ink droplet region corresponding to the test printed sub-pixel pit image, and the second area is the area of ​​the bridging ink droplet region corresponding to the first sub-pixel pit.

[0015] In the above scheme, when dealing with droplet bridging defects, the area of ​​the bridging droplet region in the test printed sub-pixel pit image is used as the criterion to determine whether the second nozzle is an abnormal nozzle. It should be noted that droplet bridging defects are generally located between two sub-pixel pits, caused by ink droplets overflowing from one or two sub-pixel pits or droplet landing point deviation, etc. Therefore, the first area mentioned above is the test printed sub-pixel pit image obtained after the nozzle under test is replaced by the backup nozzle, including the image around the sub-pixel pit (i.e., the image corresponding to the distance between adjacent sub-pixel pits); the second area mentioned above is the area of ​​the bridging droplet region corresponding to the first sub-pixel pit, which is the area of ​​the bridging droplet region around the first sub-pixel pit (i.e., the distance between adjacent sub-pixel pits).

[0016] In one possible implementation, the plurality of sub-pixel pits include a second sub-pixel pit, which corresponds to a second print nozzle group; the second print nozzle group further includes a third nozzle, which is any nozzle in the second print nozzle group other than the first nozzle; the positioning method further includes: performing an ink droplet observation operation on the third nozzle to obtain ink droplet parameters of the ink droplets ejected by the third nozzle, the ink droplet parameters including ink droplet volume, ink droplet ejection velocity, and ink droplet ejection angle; if the ink droplet parameters of the ink droplets ejected by the third nozzle are not within a preset parameter range, then the third nozzle is confirmed as an abnormal nozzle; the preset parameter range includes a range of ink droplet volume, a range of ink droplet ejection velocity, and a range of ink droplet ejection angle.

[0017] The above scheme discloses another method for determining whether the nozzle to be detected is an abnormal nozzle. After identifying abnormal nozzles in the sub-pixel pits through cross-referencing, ink droplet observation is performed on the third nozzle.

[0018] The specific observation methods for ink droplet observation are familiar to those skilled in the art and will not be described in this manual. By setting preset parameter ranges, each nozzle to be detected is screened individually. This method is applicable to both ink droplet satellite defects and ink droplet bridging defects, but it is more time-consuming than the method used in the backup nozzle example. Furthermore, the preset parameter range must be set based on empirical values; that is, the nozzles corresponding to discrete ink droplets are identified as abnormal nozzles by using the preset parameter range. Additionally, if any ink droplet parameter is outside the preset reference range, the third nozzle can be identified as an abnormal nozzle.

[0019] In one possible implementation, the plurality of sub-pixel pits include a third sub-pixel pit, which corresponds to a third print nozzle group; the third print nozzle group further includes a fourth nozzle, which is any nozzle in the third print nozzle group other than the first nozzle; the positioning method further includes: performing print deviation detection on the fourth nozzle to obtain a deviation value of the fourth nozzle, wherein the deviation value is the X-axis deviation value and Y-axis deviation value of the ink droplet landing point, the X-axis deviation value is the distance between the X-axis coordinate of the ink droplet landing point and a preset X-axis standard coordinate, and the Y-axis deviation value is the distance between the Y-axis coordinate of the ink droplet landing point and a preset Y-axis standard coordinate; if the deviation value of the fourth nozzle is greater than a preset deviation threshold, then the fourth nozzle is determined to be an abnormal nozzle; wherein the preset deviation threshold includes a preset X-axis deviation threshold and a preset Y-axis deviation threshold, and the preset deviation threshold is determined by the discrete ink droplet deviation values ​​in the print deviation value group corresponding to the third print nozzle group.

[0020] The above solution discloses a method for determining whether an nozzle to be tested is an abnormal nozzle by detecting printing deviation. When ink droplets ejected from a nozzle cause defects in sub-pixel pits, the landing point of the ink droplet, equivalent to a preset standard point (also known as a standard coordinate), will generally have a significant deviation (also known as a discrete point); this can be identified through printing deviation detection.

[0021] In one possible implementation, multiple printing nozzle groups are identified when the first nozzle is an abnormal nozzle, and the number of multiple printing nozzle groups is greater than or equal to 3.

[0022] In the above scheme, the aim is to illustrate that in the method of cross-determining abnormal nozzles for sub-pixel pits, when the number of multiple print nozzle groups is greater than or equal to 3, it can be considered that the first nozzle can be completely identified as an abnormal nozzle. That is, when the first nozzle exists in all three print nozzle groups (three sub-pixel pits with the same ink droplet defect type, corresponding to three print nozzle groups), it is considered that the first nozzle can be completely identified as an abnormal nozzle.

[0023] In one possible implementation, the backup nozzle is a non-disabled nozzle, and the backup nozzle of the second nozzle is obtained in any of the following ways: both the backup nozzle and the second nozzle are matched with the ink droplet landing point range of the first sub-pixel pit; the distance between the Y-axis coordinate of the backup nozzle and the Y-axis coordinate of the second nozzle is less than the distance between the Y-axis coordinate of the non-backup nozzle and the Y-axis coordinate of the second nozzle.

[0024] In the above scheme, a nozzle to be detected has one or more backup nozzles. In the pixel pit printing scenario, matching nozzles with droplet points in pixel pits generally takes two forms: one is to consider the droplet distribution, and the other is to consider the total volume of droplets in the sub-pixel pit. For the former, the Y-axis coordinate of the backup nozzle needs to be close to the Y-axis coordinate of the nozzle to be detected (i.e., the nozzle that the backup nozzle will replace), and the backup nozzle is the nozzle closest to the nozzle to be detected among many nozzles; for the latter, the backup nozzle needs to be within the droplet droplet range of the sub-pixel pit.

[0025] The second aspect of this application discloses an inkjet printer, including a processor, a memory, a user interface, and a network interface. The memory is used to store instructions, and both the user interface and the network interface are used to communicate with other devices. The processor is used to execute the instructions stored in the memory to enable the inkjet printer to perform any of the above-described methods for locating abnormal nozzles in pixel pit printing.

[0026] The beneficial effects of this application include: For multiple printing nozzle groups corresponding to multiple sub-pixel pits of the same ink droplet defect type, if these printing nozzle groups share a common nozzle, that nozzle is likely an abnormal nozzle. Since the defects caused by ink droplets ejected from the abnormal nozzle are generally of the same type after nozzle abnormality, and there is a one-to-one correspondence between sub-pixel pits and printing nozzle groups (determined during the printing planning stage before inkjet printing), abnormal nozzles in a sub-pixel pit can be cross-identified using the above method. For possible abnormal nozzles in a sub-pixel pit that have not yet been located, test printing is performed by replacing them with backup nozzles, and the abnormal nozzles are located based on the test printing results. In this process, the nozzles to be detected are replaced one by one with backup nozzles (backup nozzles are backups of the nozzles to be detected), and then the abnormal nozzles are located based on the test printing results. This method can screen all the nozzles to be detected in a sub-pixel pit. For example, a test print of a sub-pixel pit image may contain ink droplet defects, but these defects differ from those in the first sub-pixel pit. This discussion requires a separate examination of the different types of ink droplet defects; the defects vary depending on the type. In the case of satellite droplet defects, the number of satellite droplets can be used as a criterion to determine if the second nozzle is abnormal. For ink droplet bridging defects, the span of the bridging droplet area in the test print sub-pixel image is used to determine if the second nozzle is abnormal. Selecting the span of the bridging droplet area allows for a qualitative assessment of the effect after the nozzle ejects ink droplets. For ink droplet bridging defects, the area of ​​the bridging droplet area in the test print sub-pixel image is used as a criterion to determine if the second nozzle is abnormal. It should be noted that ink droplet bridging defects are generally located between two sub-pixel pits, caused by ink droplets overflowing from one or two sub-pixel pits or by ink droplet landing point deviation. Therefore, the first area mentioned above is the test printed sub-pixel pit image obtained after the nozzle under test is replaced by the backup nozzle, including the image around the sub-pixel pit (i.e., the image corresponding to the distance between adjacent sub-pixel pits). The second area mentioned above is the area of ​​the bridging ink droplet area corresponding to the first sub-pixel pit, which is the area of ​​the bridging ink droplet area around the first sub-pixel pit (i.e., the distance between adjacent sub-pixel pits). After the abnormal nozzles in the sub-pixel pits are determined by cross-referencing, ink droplet observation is performed on the third nozzle. The nozzle under test is judged to be abnormal by printing deviation detection. If the ink droplets ejected by the nozzle cause defects in the sub-pixel pits, then the landing point of the ink droplet, equivalent to a preset standard point (also called standard coordinate), will generally have a significant deviation (also called discrete point). This can be identified by printing deviation detection. Attached Figure Description

[0027] Figure 1 is a schematic flowchart of a method for locating abnormal nozzles in pixel pit printing disclosed in this application; Figure 2 is a schematic diagram of a droplet bridging defect disclosed in this application; Figure 3 is a schematic diagram of another droplet bridging defect disclosed in this application; Figure 4 is a schematic diagram of a droplet satellite droplet defect disclosed in this application; Figure 5 is a schematic diagram of the landing point for droplet printing deviation detection disclosed in this application; Figure 6 is a schematic diagram of an inkjet printer disclosed in this application. Detailed Implementation

[0028] To enable those skilled in the art to better understand the technical solutions in this specification, the technical solutions in the embodiments of this specification will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0029] In the description of the embodiments of this application, the words "for example" or "for instance" are used to indicate examples, illustrations, or explanations. Any embodiment or design that is described as "for example" or "for instance" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or design options. Rather, the use of the words "for example" or "for instance" is intended to present the relevant concepts in a specific manner.

[0030] In the description of the embodiments of this application, the term "multiple" means two or more. For example, multiple systems means two or more systems, and multiple screen terminals means two or more screen terminals. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the indicated technical features. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature. The terms "comprising," "including," "having," and variations thereof all mean "including but not limited to," unless otherwise specifically emphasized.

[0031] In this manual, the ink droplet defects referred to as pixel pits mainly refer to satellite drops and ink droplet bridging defects, excluding ink droplet misprint defects. Ink droplet misprint defects can be resolved through compensatory printing methods, which will not be explained here.

[0032] This specification discloses a method for locating abnormal nozzles in pixel pit printing, the method comprising steps S101-S103.

[0033] Step S101: Obtain images of multiple sub-pixel pits with the same ink droplet defect type on the substrate. The ink droplet defect type includes ink droplet satellite defects and ink droplet bridging defects.

[0034] Step S102: Obtain multiple printing nozzle groups corresponding to multiple sub-pixel pits. One sub-pixel pit corresponds to one printing nozzle group, and one printing nozzle group includes multiple nozzles.

[0035] Step S103: If the first nozzle exists in multiple printing nozzle groups, then the first nozzle is confirmed to be an abnormal nozzle.

[0036] At this point, by considering multiple print nozzle groups corresponding to multiple sub-pixel pits of the same ink droplet defect type, if these print nozzle groups share a common nozzle, that nozzle is likely an abnormal nozzle. Since defects caused by ink droplets ejected from abnormal nozzles are generally of the same type, and since there is a one-to-one correspondence between sub-pixel pits and print nozzle groups—a correspondence determined during the print planning stage before inkjet printing—abnormal nozzles within a sub-pixel pit can be cross-identified using the above method.

[0037] Furthermore, the defect type obtained after identifying and classifying defects in subpixel pit images can be confirmed using methods such as defect feature recognition and similarity comparison; this will not be explained or limited. This specification primarily discusses ink droplet satellite droplet defects and ink droplet bridging defects in subpixel pits; in inkjet printing scenarios involving pixel pits, there are also subpixel pit missing print defects, which can be resolved through compensation printing, and will not be discussed here.

[0038] Furthermore, the aforementioned method of cross-identifying abnormal nozzles for subpixel pits applies to both droplet satellite droplet defects and droplet bridging defects. During the print planning process, the first nozzle in the printhead module is used as a reference, and the nozzles are sorted according to their Y-axis coordinates, sequentially assigning nozzle numbers and coordinates. In this method, locating an abnormal nozzle not only identifies its nozzle number but also determines its coordinates within a specific printhead in the printhead module. In other words, locating an abnormal nozzle in this specification means that its nozzle number and coordinates are simultaneously determined.

[0039] Furthermore, the aforementioned method of cross-identifying anomalous nozzles in sub-pixel pits cannot locate all anomalous nozzles. For example, there might be anomalous nozzles a and b in sub-pixel pit A, but only anomalous nozzle b in sub-pixel pit B; the above method can only locate anomalous nozzle b, not anomalous nozzle a. Therefore, it is necessary to discuss any anomalous nozzles that may exist in sub-pixel pits but have not yet been located.

[0040] In one example, multiple subpixel pits include a first subpixel pit, which corresponds to a first print nozzle group; the first print nozzle group also includes a second nozzle, which is any nozzle in the first print nozzle group other than the first nozzle; the positioning method further includes: replacing the second nozzle in the first print nozzle group with a backup nozzle to obtain a backup nozzle group; the backup nozzle is a backup nozzle of the second nozzle; performing test printing with the backup nozzle group and obtaining a test print subpixel pit image after printing; determining whether the test print subpixel pit image has ink droplet defects in the first subpixel pit; if the test print subpixel pit image has ink droplet defects in the first subpixel pit, then the second nozzle is determined to be a normal nozzle; if the test print subpixel pit image does not have ink droplet defects in the first subpixel pit, then the second nozzle is determined to be an abnormal nozzle.

[0041] In the example above, for any abnormal nozzles that may exist in the subpixel pits but have not yet been located, test printing is performed by replacing them with backup nozzles. The abnormal nozzles are then located based on the test print results. During this process, each nozzle to be detected (a backup nozzle is a backup of the nozzle to be detected) is replaced with a backup nozzle one by one, and then the abnormal nozzles are located based on the test print results. This method can screen all the nozzles to be detected in the subpixel pits.

[0042] At this point, to determine whether there are ink droplet defects in the test-printed subpixel pit image that are similar to those in the first subpixel pit, methods such as ink droplet defect feature recognition or image difference can be used. No further explanation or limitation is provided. Regardless of the type of ink droplet defect, if the test-printed subpixel pit image contains an ink droplet defect from the first subpixel pit, then the second nozzle can be confirmed as an abnormal nozzle.

[0043] In addition, there are cases where the ink droplet defect of the first sub-pixel pit is absent from the test-printed sub-pixel pit image; and cases where the ink droplet defect of the first sub-pixel pit is present in the test-printed sub-pixel pit image, but the ink droplet defect in the test-printed sub-pixel pit image differs from the ink droplet defect of the first sub-pixel pit. These will be explained separately below.

[0044] In one example, when the ink droplet defect type is an ink droplet satellite droplet defect, the positioning method further includes: if the first quantity is less than the second quantity, and the first quantity is not 0, then the second nozzle is confirmed to be an abnormal nozzle; wherein, the first quantity is the number of satellite drops in the test printed sub-pixel pit image, and the second quantity is the number of satellite drops in the first sub-pixel pit.

[0045] At this point, a test print of a sub-pixel pit image is disclosed, showing ink droplet defects, but these defects differ from those in the first sub-pixel pit. This situation requires a separate discussion of the types of ink droplet defects; different types of ink droplet defects result in different defects. In the case of ink droplet satellite defects, the number of ink droplet satellites can be used as a criterion to determine whether the second nozzle is an abnormal nozzle.

[0046] It should be noted that when the first quantity is 0, it means that there are no satellite droplet numbers in the test printed subpixel pit image. This means that there are no satellite droplet defects in the test printed subpixel pit image, and the second nozzle is determined to be an abnormal nozzle. This is consistent with the solution in the previous example (that is, the above test printed subpixel pit image does not have ink droplet defects in the first subpixel pit, this example), so this situation is excluded in this example.

[0047] In addition, the first quantity is generally not greater than the second quantity; when the first quantity is equal to the second quantity, it means that the nozzle to be tested in this judgment is a normal nozzle, which causes the test printing result after replacement to be the same as the printing result of the first sub-pixel pit (both have ink droplet satellite drop defects).

[0048] Figure 4 illustrates two satellite drops in subpixel pit 220: a solid (solid line) satellite drop 260 and a hollow (dashed line) satellite drop 270. In the test print of the subpixel pit image, there is only one satellite drop, the solid (solid line) satellite drop 260; in the first subpixel pit, there are two satellite drops: the solid (solid line) satellite drop 260 and the hollow (dashed line) satellite drop 270. This indicates that the second nozzle is an abnormal nozzle, meaning that after the second nozzle is replaced by a backup nozzle (normal nozzle), the number of satellite drops decreases (the satellite drop defect is improved); it also indicates that there are other abnormal nozzles in the first print nozzle group corresponding to the first subpixel pit.

[0049] In one example, when the droplet defect type is a droplet bridging defect, the positioning method further includes: if the first span is less than the second span, and the first span is not 0, then the second nozzle is confirmed to be an abnormal nozzle; wherein, the first span is the span of the bridging droplet area in the test printed sub-pixel pit image in the X-axis direction or the Y-axis direction, the second span is the span of the bridging droplet area in the first sub-pixel pit in the X-axis direction or the Y-axis direction, and both the first span and the second span are spans in the X-axis direction or both are spans in the Y-axis direction.

[0050] In this example, when addressing droplet bridging defects, the span of the bridging droplet region in the test print subpixel pit image is assessed to determine if the second nozzle is an abnormal nozzle. Selecting the span of the bridging droplet region allows for a qualitative assessment of the effect after the nozzle ejects the droplets, and the span can be directly obtained through image recognition (e.g., the number of pixels occupied by the bridging droplet region in the X-axis or Y-axis direction in the image is used as the span). It should be noted that the comparison between the first and second spans must be in the same direction (i.e., both in the X-axis direction or both in the Y-axis direction).

[0051] It should be noted that ink droplet bridging defects are generally located between two sub-pixel pits (as shown in Figures 2 and 3, the first sub-pixel pit can be either R sub-pixel pit 210 or G sub-pixel pit 220), caused by ink droplets overflowing from one or two sub-pixel pits or ink droplet landing point deviation. Therefore, the first span mentioned above is the span of the bridging region in the test printed sub-pixel pit image obtained after the nozzle under test is replaced by the backup nozzle, including the image around the sub-pixel pit (i.e., the image corresponding to the distance between adjacent sub-pixel pits); the second span mentioned above is the span of the bridging ink droplet area corresponding to the first sub-pixel pit, which is the span of the bridging ink droplet area around the first sub-pixel pit (i.e., the distance between adjacent sub-pixel pits).

[0052] At this point, when the first span is 0, that is, when the span of the bridging ink droplet area in the test printed subpixel pit image is 0 in the X-axis or Y-axis direction, it means that there is no bridging defect in the test printed subpixel pit image. It can be determined that the second nozzle is an abnormal nozzle. However, this is consistent with the previous example (that is, the above test printed subpixel pit image does not have ink droplet defects in the first subpixel pit, this example), so this case is excluded in this example.

[0053] In addition, the first span is generally not greater than the second span; and when the first span is equal to the second span, it indicates that the nozzle to be tested in this judgment is a normal nozzle, resulting in the test printing result after replacement being the same as the printing result of the first sub-pixel pit (both have ink droplet bridging defects).

[0054] Figures 2 and 3 are examples. Figure 2 illustrates the bridging droplet area 240 corresponding to the first sub-pixel pit, and shows that the span of the bridging droplet area 240 along the X-axis is Xa, and the span along the Y-axis is Ya; the R sub-pixel pit 210, G sub-pixel pit 220, and B sub-pixel pit 230 together form the pixel pit 200. Figure 3 illustrates the bridging droplet area 250 of the test printed sub-pixel pit image, and shows that the span of the bridging droplet area 250 along the X-axis is Xb, and the span along the Y-axis is Yb. Here, Xa = Xb, but Ya > Yb, which confirms that the second nozzle is an abnormal nozzle; this can be understood as the bridging droplet area being improved because the second nozzle, being an abnormal nozzle, was replaced by a backup nozzle (normal nozzle).

[0055] In one example, when the droplet defect type is a droplet bridging defect, the positioning method further includes: if the first area is smaller than the second area and the first area is not 0, then the second nozzle is confirmed to be an abnormal nozzle; wherein, the first area is the area of ​​the bridging droplet region corresponding to the test printed sub-pixel pit image, and the second area is the area of ​​the bridging droplet region corresponding to the first sub-pixel pit.

[0056] In this example, when dealing with ink droplet bridging defects, the area of ​​the bridging ink droplet region in the test printed subpixel pit image is used as the criterion to determine whether the second nozzle is an abnormal nozzle.

[0057] It should be noted that ink droplet bridging defects are generally located between two sub-pixel pits, caused by ink droplets overflowing from one or two sub-pixel pits or ink droplet landing point deviations. Therefore, the first area mentioned above is the area of ​​the bridging region in the test printed sub-pixel pit image obtained after the nozzle under test is replaced by the backup nozzle, including the image around the sub-pixel pit (i.e., the image corresponding to the distance between adjacent sub-pixel pits). The second area mentioned above is the area of ​​the bridging ink droplet area corresponding to the first sub-pixel pit, which is the area of ​​the bridging ink droplet area around the first sub-pixel pit (i.e., the distance between adjacent sub-pixel pits).

[0058] At this point, the area of ​​the bridging ink droplet region can be obtained through image recognition or by measuring the number of image pixels occupied, without further explanation or limitation. When the first area is 0, that is, when the area of ​​the bridging ink droplet region in the test printed subpixel pit image is 0, it means that there is no bridging defect in the test printed subpixel pit image, and it can be determined that the second nozzle is an abnormal nozzle. However, this is consistent with the previous example (that is, the above test printed subpixel pit image does not have ink droplet defects in the first subpixel pit, this example), so this situation is excluded in this example.

[0059] Furthermore, the first area is generally not larger than the second area; and when the first area is equal to the second area, it indicates that the nozzle to be tested in this judgment is a normal nozzle, resulting in the test printing result after replacement being the same as the printing result of the first sub-pixel pit (both have ink droplet bridging defects).

[0060] As illustrated in Figures 2 and 3 above. The area of ​​the bridging droplet region 250 corresponding to the test printed subpixel pit image is the first area, and the area of ​​the bridging droplet region 240 corresponding to the first subpixel pit is the second area. Clearly, the first area is smaller than the second area, thus determining the second nozzle as an abnormal nozzle. This can be understood as the bridging droplet region being "improved" after the second nozzle is replaced as a backup nozzle for the normal nozzle. This also indicates that there are other abnormal nozzles to be detected in the first nozzle group corresponding to the first subpixel pit.

[0061] In one example, multiple sub-pixel pits include a second sub-pixel pit, which corresponds to a second print nozzle group; the second print nozzle group also includes a third nozzle, which is any nozzle in the second print nozzle group other than the first nozzle; the positioning method further includes: performing an ink droplet observation operation on the third nozzle to obtain the ink droplet parameters ejected by the third nozzle, the ink droplet parameters including ink droplet volume, ink droplet ejection speed, and ink droplet ejection angle; if the ink droplet parameters ejected by the third nozzle are not within a preset parameter range, then the third nozzle is confirmed as an abnormal nozzle; the preset parameter range includes the ink droplet volume range, the ink droplet ejection speed range, and the ink droplet ejection angle range.

[0062] This example discloses another method for determining whether an nozzle to be detected is an abnormal nozzle. After identifying abnormal nozzles in the sub-pixel pits through the above cross-identification, ink droplet observation is performed on the third nozzle.

[0063] The specific observation methods for ink droplet observation are familiar to those skilled in the art and will not be described in this manual. By setting preset parameter ranges, each nozzle to be detected is screened individually. This method is applicable to both ink droplet satellite defects and ink droplet bridging defects, but it is more time-consuming than the method used in the backup nozzle example. Furthermore, the preset parameter range must be set based on empirical values; that is, the nozzles corresponding to discrete ink droplets are identified as abnormal nozzles by using the preset parameter range. Additionally, if any ink droplet parameter is outside the preset reference range, the third nozzle can be identified as an abnormal nozzle.

[0064] It should be noted that during the print planning process, droplet observation is also used to screen the nozzles of the printhead module. This droplet screening identifies and disables abnormal nozzles (preventing them from participating in subsequent print planning). However, the range of droplet screening parameters during print planning is completely different from the preset parameter range in the example above. Print planning filters based on printing requirements (printing speed, printing frequency, etc.); while the preset parameter range in the example above filters relatively discrete nozzles (those corresponding to discrete droplets) from the nozzles after print planning, resulting in a more detailed and precise screening.

[0065] In one example, multiple sub-pixel pits include a third sub-pixel pit, which corresponds to a third print nozzle group; the third print nozzle group also includes a fourth nozzle, which is any nozzle in the third print nozzle group other than the first nozzle; the positioning method further includes: performing print deviation detection on the fourth nozzle to obtain a deviation value of the fourth nozzle, wherein the deviation value is the X-axis deviation value and Y-axis deviation value of the ink droplet landing point, the X-axis deviation value is the distance between the X-axis coordinate of the ink droplet landing point and a preset X-axis standard coordinate, and the Y-axis deviation value is the distance between the Y-axis coordinate of the ink droplet landing point and a preset Y-axis standard coordinate; if the deviation value of the fourth nozzle is greater than a preset deviation threshold, then the fourth nozzle is determined to be an abnormal nozzle; wherein, the preset deviation threshold includes a preset X-axis deviation threshold and a preset Y-axis deviation threshold, and the preset deviation threshold is determined by the discrete ink droplet deviation values ​​in the print deviation value group corresponding to the third print nozzle group.

[0066] At this point, a method for determining whether an nozzle to be inspected is an abnormal nozzle by detecting printing deviation is disclosed. If the ink droplets ejected from the nozzle cause defects in the sub-pixel pits, then the landing point of the ink droplets, equivalent to a preset standard point (also known as a standard coordinate), will generally have a significant deviation (also known as a discrete point); this can be identified through printing deviation detection.

[0067] At this point, the printing deviation of the nozzle includes both X-axis and Y-axis deviation values. If either the X-axis or Y-axis deviation exceeds the corresponding preset deviation threshold, it is considered an abnormal nozzle. This method is applicable to both droplet satellite droplet defects and droplet bridging defects. While more time-consuming than the method in the backup nozzle example, it is more efficient than judging multiple parameters in the droplet observation example. Furthermore, the preset deviation range must be set based on empirical values; that is, the nozzle corresponding to discrete droplets is identified as an abnormal nozzle by using the preset deviation range.

[0068] Figure 5 illustrates the baselines for the X-axis and Y-axis coordinates of the standard landing point 300. The discrete landing point 320 along the Y-axis has a Y-axis deviation value Ys that is discrete among many landing points (also known as having a large or maximum Y-axis offset). Therefore, a Y-axis deviation threshold can be set to filter out the discrete landing point 320 along the Y-axis, and the nozzle corresponding to the discrete landing point 320 in the Y-axis direction is identified as an abnormal nozzle. Similarly, the discrete landing point 310 along the X-axis has an X-axis deviation value Xs that is discrete among many landing points (also known as having a large or maximum X-axis offset). Therefore, an X-axis offset threshold can be set to filter out the discrete landing point 310 along the X-axis, and the nozzle corresponding to the discrete landing point 310 in the X-axis direction is identified as an abnormal nozzle. Of course, a discrete landing point can also be discrete in both the X-axis and Y-axis directions; in this case, the nozzle corresponding to that discrete landing point can also be identified as an abnormal nozzle.

[0069] In one example, multiple print nozzle groups are identified when the first nozzle is an abnormal nozzle, and the number of multiple print nozzle groups is greater than or equal to 3.

[0070] In this context, to illustrate the method for cross-identifying abnormal nozzles in subpixel pits, when the number of multiple print nozzle groups is greater than or equal to 3, it can be considered that the first nozzle can be completely identified as an abnormal nozzle. That is, when the first nozzle exists in all three print nozzle groups (three subpixel pits with the same droplet defect type, corresponding to three print nozzle groups) (the other nozzles are different), it is considered that the first nozzle can be completely identified as an abnormal nozzle.

[0071] Furthermore, when the number of multiple print nozzle groups is less than 3, i.e., the number of multiple print nozzle groups is 2, it is also possible to confirm that the first nozzle is an abnormal nozzle. This number limit is greater than or equal to 3, which is suitable for scenarios with higher requirements for abnormal nozzle positioning (e.g., in the case of printing large-size substrates, where the number of nozzles printed in the printhead module is limited).

[0072] In one example, the backup nozzle is a non-disabled nozzle, and the backup nozzle of the second nozzle is obtained in any of the following ways: both the backup nozzle and the second nozzle match the ink droplet landing point range of the first sub-pixel pit; the distance between the Y-axis coordinate of the backup nozzle and the Y-axis coordinate of the second nozzle is less than the distance between the Y-axis coordinate of the non-backup nozzle and the Y-axis coordinate of the second nozzle.

[0073] At this point, a nozzle to be detected has one or more backup nozzles. In pixel pit printing scenarios, matching nozzles with droplet points in pixel pits generally involves two methods: one considers the droplet distribution, and the other considers the total volume of droplets in the sub-pixel pit. For the former, the Y-axis coordinate of the backup nozzle needs to be close to the Y-axis coordinate of the nozzle to be detected (i.e., the nozzle the backup nozzle will replace). The backup nozzle is the nozzle closest to the nozzle to be detected among all the nozzles. For the latter, the backup nozzle needs to be within the droplet droplet range of the sub-pixel pit. No specific instructions or restrictions are given regarding the selection of backup nozzles.

[0074] This specification also discloses an inkjet printer, including a processor, a memory, a user interface, and a network interface. The memory is used to store instructions, and both the user interface and the network interface are used to communicate with other devices. The processor is used to execute the instructions stored in the memory to enable the inkjet printer to perform any of the above-described methods for locating abnormal nozzles in pixel pit printing.

[0075] Specifically, a method for locating abnormal nozzles in pixel pit printing includes: acquiring images of multiple sub-pixel pits on a substrate that have the same type of ink droplet defect, the ink droplet defect type including ink droplet satellite defects and ink droplet bridging defects; acquiring multiple printing nozzle groups corresponding to the multiple sub-pixel pits, one sub-pixel pit corresponding to one printing nozzle group, and one printing nozzle group including multiple nozzles; if a first nozzle exists in all of the multiple printing nozzle groups, then the first nozzle is identified as an abnormal nozzle.

[0076] In one example, multiple subpixel pits include a first subpixel pit, which corresponds to a first print nozzle group; the first print nozzle group also includes a second nozzle, which is any nozzle in the first print nozzle group other than the first nozzle; the positioning method further includes: replacing the second nozzle in the first print nozzle group with a backup nozzle to obtain a backup nozzle group; the backup nozzle is a backup nozzle of the second nozzle; performing test printing with the backup nozzle group and obtaining a test print subpixel pit image after printing; determining whether the test print subpixel pit image has ink droplet defects in the first subpixel pit; if the test print subpixel pit image has ink droplet defects in the first subpixel pit, then the second nozzle is determined to be a normal nozzle; if the test print subpixel pit image does not have ink droplet defects in the first subpixel pit, then the second nozzle is determined to be an abnormal nozzle.

[0077] In one example, when the ink droplet defect type is an ink droplet satellite droplet defect, the positioning method further includes: if the first quantity is less than the second quantity, and the first quantity is not 0, then the second nozzle is confirmed to be an abnormal nozzle; wherein, the first quantity is the number of satellite drops in the test printed sub-pixel pit image, and the second quantity is the number of satellite drops in the first sub-pixel pit.

[0078] In one example, when the droplet defect type is a droplet bridging defect, the positioning method further includes: if the first span is less than the second span, and the first span is not 0, then the second nozzle is confirmed to be an abnormal nozzle; wherein, the first span is the span of the bridging droplet area in the test printed sub-pixel pit image in the X-axis direction or the Y-axis direction, the second span is the span of the bridging droplet area in the first sub-pixel pit in the X-axis direction or the Y-axis direction, and both the first span and the second span are spans in the X-axis direction or both are spans in the Y-axis direction.

[0079] In one example, when the droplet defect type is a droplet bridging defect, the positioning method further includes: if the first area is smaller than the second area and the first area is not 0, then the second nozzle is confirmed to be an abnormal nozzle; wherein, the first area is the area of ​​the bridging droplet region corresponding to the test printed sub-pixel pit image, and the second area is the area of ​​the bridging droplet region corresponding to the first sub-pixel pit.

[0080] In one example, multiple sub-pixel pits include a second sub-pixel pit, which corresponds to a second print nozzle group; the second print nozzle group also includes a third nozzle, which is any nozzle in the second print nozzle group other than the first nozzle; the positioning method further includes: performing an ink droplet observation operation on the third nozzle to obtain the ink droplet parameters ejected by the third nozzle, the ink droplet parameters including ink droplet volume, ink droplet ejection speed, and ink droplet ejection angle; if the ink droplet parameters ejected by the third nozzle are not within a preset parameter range, then the third nozzle is confirmed as an abnormal nozzle; the preset parameter range includes the ink droplet volume range, the ink droplet ejection speed range, and the ink droplet ejection angle range.

[0081] In one example, multiple sub-pixel pits include a third sub-pixel pit, which corresponds to a third print nozzle group; the third print nozzle group also includes a fourth nozzle, which is any nozzle in the third print nozzle group other than the first nozzle; the positioning method further includes: performing print deviation detection on the fourth nozzle to obtain a deviation value of the fourth nozzle, wherein the deviation value is the X-axis deviation value and Y-axis deviation value of the ink droplet landing point, the X-axis deviation value is the distance between the X-axis coordinate of the ink droplet landing point and a preset X-axis standard coordinate, and the Y-axis deviation value is the distance between the Y-axis coordinate of the ink droplet landing point and a preset Y-axis standard coordinate; if the deviation value of the fourth nozzle is greater than a preset deviation threshold, then the fourth nozzle is determined to be an abnormal nozzle; wherein, the preset deviation threshold includes a preset X-axis deviation threshold and a preset Y-axis deviation threshold, and the preset deviation threshold is determined by the discrete ink droplet deviation values ​​in the print deviation value group corresponding to the third print nozzle group.

[0082] In one example, multiple print nozzle groups are identified when the first nozzle is an abnormal nozzle, and the number of multiple print nozzle groups is greater than or equal to 3.

[0083] In one example, the backup nozzle is a non-disabled nozzle, and the backup nozzle of the second nozzle is obtained in any of the following ways: both the backup nozzle and the second nozzle match the ink droplet landing point range of the first sub-pixel pit; the distance between the Y-axis coordinate of the backup nozzle and the Y-axis coordinate of the second nozzle is less than the distance between the Y-axis coordinate of the non-backup nozzle and the Y-axis coordinate of the second nozzle.

[0084] It should be noted that the above embodiments of the apparatus are only illustrated by the division of the above functional modules. In practical applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above. In addition, the apparatus and method embodiments provided in the above embodiments belong to the same concept, and the specific implementation process can be found in the method embodiments, which will not be repeated here.

[0085] The specification also discloses a computer-readable storage medium storing instructions that, when executed, perform the method described above.

[0086] This embodiment also discloses an electronic device, which may be an inkjet printer, to perform the above-described method. Referring to FIG6, the electronic device may include: at least one processor 601, at least one communication bus 602, a display 603, a network interface 604, and at least one memory 605.

[0087] The communication bus 602 is used to enable communication between these components.

[0088] The display 603 may include a display screen and a camera.

[0089] The network interface 604 may optionally include a standard wired interface or a wireless interface (such as a Wi-Fi interface).

[0090] The processor 601 may include one or more processing cores. The processor 601 connects to various parts of the server using various interfaces and lines, and performs various server functions and processes data by running or executing instructions, programs, code sets, or instruction sets stored in the memory 605, and by calling data stored in the memory 605. Optionally, the processor 601 may be implemented using at least one hardware form of Digital Signal Processing (DSP), Field-Programmable Gate Array (FPGA), or Programmable Logic Array (PLA). The processor 601 may integrate one or a combination of several of the following: Central Processing Unit (CPU), Graphics Processing Unit (GPU), and modem. The CPU primarily handles the operating system, user interface, and applications; the GPU is responsible for rendering and drawing the content required for display; and the modem handles wireless communication. It is understood that the modem may also not be integrated into the processor 601 and may be implemented as a separate chip.

[0091] The memory 605 may include random access memory (RAM) or read-only memory. Optionally, the memory 605 may include a non-transitory computer-readable storage medium. The memory 605 may be used to store instructions, programs, code, code sets, or instruction sets. The memory 605 may include a program storage area and a data storage area. The program storage area may store instructions for implementing an operating system, instructions for at least one function (such as touch functionality, sound playback functionality, image playback functionality, etc.), instructions for implementing the various method embodiments described above, etc.; the data storage area may store data involved in the various method embodiments described above, etc. Optionally, the memory 605 may also be at least one storage device located remotely from the aforementioned processor 601. As shown in the figure, the memory 605, as a computer storage medium, may include an operating system, a network communication module, and application programs for a display module.

[0092] In the electronic device shown in Figure 6, the display 603 is mainly used to provide an input interface for the user and to obtain the user input data; while the processor 601 can be used to call the application program stored in the memory 605. When executed by one or more processors 601, the electronic device performs one or more methods as described in the above embodiments.

[0093] It should be noted that, for the sake of simplicity, the foregoing method embodiments are all described as a series of actions. However, those skilled in the art should understand that this application is not limited to the described order of actions, as some steps may be performed in other orders or simultaneously according to this application. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and modules involved are not necessarily essential to this application.

[0094] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0095] In the several embodiments provided in this application, it should be understood that the disclosed apparatus can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the shown or discussed mutual couplings or direct couplings or communication connections may be through some service interfaces; indirect couplings or communication connections between apparatuses or units may be electrical or other forms.

[0096] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0097] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0098] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage device (CMD). Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a memory 605 and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this application. The aforementioned memory 605 includes various media capable of storing program code, such as a USB flash drive, external hard drive, magnetic disk, or optical disk.

[0099] The above are merely exemplary embodiments of this disclosure and should not be construed as limiting the scope of this disclosure. Any equivalent changes and modifications made in accordance with the teachings of this disclosure shall still fall within the scope of this disclosure. Those skilled in the art will readily conceive of other embodiments of this disclosure upon considering the specification and the disclosure of practical truth. This application is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not described in this disclosure. The specification and embodiments are considered exemplary only, and the scope and spirit of this disclosure are defined by the claims.

Claims

1. A method for locating abnormal nozzles in pixel pit printing, characterized in that, The positioning method includes: acquiring images of multiple sub-pixel pits on a substrate that have the same type of ink droplet defect, wherein the ink droplet defect type includes ink droplet satellite droplet defects and ink droplet bridging defects; acquiring multiple printing nozzle groups corresponding to the multiple sub-pixel pits, wherein one sub-pixel pit corresponds to one printing nozzle group, and one printing nozzle group includes multiple nozzles; if a first nozzle is present in all of the multiple printing nozzle groups, then the first nozzle is confirmed to be an abnormal nozzle.

2. The positioning method according to claim 1, characterized in that, The multiple sub-pixel pits include a first sub-pixel pit, which corresponds to a first print nozzle group; the first print nozzle group also includes a second nozzle, which is any nozzle in the first print nozzle group other than the first nozzle; the positioning method further includes: replacing the second nozzle in the first print nozzle group with a backup nozzle to obtain a backup nozzle group; the backup nozzle is a backup nozzle of the second nozzle; performing test printing with the backup nozzle group and obtaining a test print sub-pixel pit image after printing; determining whether the test print sub-pixel pit image has an ink droplet defect in the first sub-pixel pit; if the test print sub-pixel pit image has an ink droplet defect in the first sub-pixel pit, then the second nozzle is determined to be a normal nozzle; if the test print sub-pixel pit image does not have an ink droplet defect in the first sub-pixel pit, then the second nozzle is determined to be an abnormal nozzle.

3. The positioning method according to claim 2, characterized in that, When the ink droplet defect type is ink droplet satellite droplet defect, the positioning method further includes: if the first quantity is less than the second quantity, and the first quantity is not 0, then the second nozzle is confirmed to be an abnormal nozzle; wherein, the first quantity is the number of satellite drops in the test printed sub-pixel pit image, and the second quantity is the number of satellite drops in the first sub-pixel pit.

4. The positioning method according to claim 2, characterized in that, When the droplet defect type is a droplet bridging defect, the positioning method further includes: if the first span is less than the second span, and the first span is not 0, then the second nozzle is confirmed to be an abnormal nozzle; wherein, the first span is the span of the bridging droplet area in the test printed sub-pixel pit image in the X-axis direction or the Y-axis direction, the second span is the span of the bridging droplet area in the first sub-pixel pit in the X-axis direction or the Y-axis direction, and both the first span and the second span are spans in the X-axis direction or both are spans in the Y-axis direction.

5. The positioning method according to claim 2, characterized in that, When the ink droplet defect type is an ink droplet bridging defect, the positioning method further includes: if the first area is smaller than the second area and the first area is not 0, then the second nozzle is confirmed to be an abnormal nozzle; wherein, the first area is the area of ​​the bridging ink droplet region corresponding to the test printed sub-pixel pit image, and the second area is the area of ​​the bridging ink droplet region corresponding to the first sub-pixel pit.

6. The positioning method according to claim 1, characterized in that, The multiple sub-pixel pits include a second sub-pixel pit, which corresponds to a second print nozzle group; the second print nozzle group also includes a third nozzle, which is any nozzle in the second print nozzle group other than the first nozzle; the positioning method further includes: performing an ink droplet observation operation on the third nozzle to obtain the ink droplet parameters ejected by the third nozzle, the ink droplet parameters including ink droplet volume, ink droplet ejection velocity, and ink droplet ejection angle; if the ink droplet parameters ejected by the third nozzle are not within a preset parameter range, the third nozzle is confirmed as an abnormal nozzle; the preset parameter range includes the ink droplet volume range, the ink droplet ejection velocity range, and the ink droplet ejection angle range.

7. The positioning method according to claim 1 or 6, characterized in that, The multiple sub-pixel pits include a third sub-pixel pit, which corresponds to a third print nozzle group; the third print nozzle group also includes a fourth nozzle, which is any nozzle in the third print nozzle group other than the first nozzle; the positioning method further includes: performing print deviation detection on the fourth nozzle to obtain the deviation value of the fourth nozzle, wherein the deviation value is the X-axis deviation value and Y-axis deviation value of the ink droplet landing point, the X-axis deviation value is the distance between the X-axis coordinate of the ink droplet landing point and the preset X-axis standard coordinate, and the Y-axis deviation value is the distance between the Y-axis coordinate of the ink droplet landing point and the preset Y-axis standard coordinate; if the deviation value of the fourth nozzle is greater than a preset deviation threshold, then the fourth nozzle is determined to be an abnormal nozzle; wherein, the preset deviation threshold includes a preset X-axis deviation threshold and a preset Y-axis deviation threshold, and the preset deviation threshold is determined by the discrete ink droplet deviation values ​​in the print deviation value group corresponding to the third print nozzle group.

8. The positioning method according to claim 1, characterized in that, When the first nozzle is identified as an abnormal nozzle, there are multiple printing nozzle groups, and the number of multiple printing nozzle groups is greater than or equal to 3.

9. The positioning method according to claim 2, characterized in that, The backup nozzle is a non-disabled nozzle, and the backup nozzle of the second nozzle can be obtained in any of the following ways: both the backup nozzle and the second nozzle match the droplet landing range of the first sub-pixel pit; the distance between the Y-axis coordinate of the backup nozzle and the Y-axis coordinate of the second nozzle is less than the distance between the Y-axis coordinate of the non-backup nozzle and the Y-axis coordinate of the second nozzle.

10. An inkjet printer, characterized in that, It includes a processor, a memory, a user interface, and a network interface. The memory is used to store instructions, and both the user interface and the network interface are used to communicate with other devices. The processor is used to execute the instructions stored in the memory so that the inkjet printer performs the positioning method for abnormal nozzles in pixel pit printing as described in any one of claims 1-9.

Images