A method and apparatus for cleaning inkjet printheads.

Abstract

This application relates to a method and apparatus for cleaning a printhead for inkjet printing, comprising the following steps: imaging the spraying surface of the printhead; marking the positions of all nozzles and numbering all nozzles; supplying cleaning fluid to the printhead and causing the printhead to spray cleaning fluid for a preset cleaning time; continuing to spray cleaning fluid from the printhead, and sequentially imaging and detecting the spraying state of all nozzles of the printhead; determining whether the spraying state of all nozzles is qualified, and counting and recording the number of unqualified nozzles; if the proportion of unqualified nozzles does not exceed the standard proportion, the printhead cleaning is completed. This application, by using the printhead to spray cleaning fluid to clean the printhead, imaging and detecting the nozzles during spraying to determine whether the cleaning is qualified, and sequentially imaging and detecting the spraying state of the nozzles and recording the number of unqualified nozzles, facilitates rapid processing of unqualified nozzles. Therefore, the cleaning and detection efficiency of the nozzles is high, the cleaning effect is guaranteed, and it meets the needs of inkjet printing processing.

Description

Technical Field

[0001] This application relates to the field of inkjet printing technology, and in particular to a method and apparatus for cleaning printheads for inkjet printing. Background Technology

[0002] Inkjet printing technology, as an additive manufacturing technology, has advantages such as non-contact, large area, no need for photomasks, rapid manufacturing, low cost of finished products, and direct pattern creation on planar / curved substrates. It is the main manufacturing technology for printed electronics that will replace the long process of photolithography / vacuum (development, etching, exposure and cleaning, etc.) and is widely used in display, sensing, chip, energy, aerospace and other fields.

[0003] Inkjet printing typically involves a printhead spraying functional liquid onto the printing surface. Because solutes in the functional liquid can adhere to the printhead's flow channels or nozzle walls, this can cause nozzle blockage and affect print quality. To ensure print quality, the printhead needs to be cleaned regularly.

[0004] In related technologies, a cleaning fluid is supplied to the printhead. By spraying the cleaning fluid, the solutes of the functional fluid in the printhead's flow channels and nozzle walls are carried out, thereby achieving the effect of cleaning the printhead. After cleaning, before using the printhead for printing, the printhead sprays out the functional fluid for printing, and the spraying effect is tested to determine whether the printhead meets the printing requirements.

[0005] However, testing the printhead's cleaning process by spraying functional fluid during a trial print before printing has several drawbacks. First, it wastes the functional fluid, increasing costs. Second, it takes longer to prepare for printing, reducing processing efficiency. Third, if the printhead fails the trial print test, it needs to be cleaned again, severely impacting the printing schedule. Summary of the Invention

[0006] This application provides a method and apparatus for cleaning printheads, which solves the following technical problems in the related art: firstly, it causes waste of functional fluid, resulting in increased costs; secondly, it leads to long printing preparation time, reducing processing efficiency; and thirdly, if the printhead fails the test print test, it needs to be cleaned again, which seriously affects the printing processing progress.

[0007] In a first aspect, a method for cleaning a printhead for inkjet printing is provided, comprising the following steps:

[0008] Image the spray surface of the nozzle;

[0009] Mark the location of all nozzles and number all nozzles;

[0010] Supply cleaning fluid to the nozzle and make the nozzle spray cleaning fluid for a preset cleaning time;

[0011] The nozzle continues to spray cleaning fluid, and the spraying status of all nozzle holes is imaged and detected in turn.

[0012] Determine whether the spraying status of all nozzles is qualified, and count the number of unqualified nozzles and record their numbers.

[0013] If the proportion of unqualified nozzles does not exceed the standard proportion, the nozzle cleaning is completed.

[0014] In some embodiments, if the proportion of defective nozzles exceeds the standard proportion, the nozzle is re-cleaned, and the re-cleaning includes:

[0015] The nozzle sprays cleaning fluid for a preset rewash time.

[0016] Then continue spraying cleaning fluid from the nozzle and perform imaging detection on different defective nozzles;

[0017] Count the number of remaining defective nozzles and record their numbers;

[0018] If the proportion of remaining unqualified nozzles is still greater than the standard proportion, the nozzle will continue to spray cleaning fluid, and imaging detection will be performed on different unqualified nozzles until the proportion of remaining unqualified nozzles does not exceed the standard proportion.

[0019] In some embodiments, the step of continuing to spray cleaning fluid from the nozzle and performing imaging detection on different defective nozzles includes:

[0020] Locate the positions of multiple defective nozzles based on their numbers;

[0021] Based on the location of multiple defective nozzles, imaging detection is performed on multiple defective nozzles sequentially.

[0022] In some embodiments, after imaging the spray surface of the nozzle, a primary screening nozzle is further included, the primary screening nozzle comprising:

[0023] Based on the imaging results of the spray surface, the proportion of defective spray holes to the total number of defective spray holes was determined.

[0024] If the non-compliance rate is less than the preset replacement rate, then the positions of all nozzles are calibrated and all nozzles are numbered; otherwise,

[0025] Replace the nozzle.

[0026] In some embodiments, the step of marking the positions of all nozzles and numbering all nozzles includes:

[0027] Record the spacing of all nozzles along the length of the nozzle head, and record the position of the nozzles at the edge, in order to determine the position of all nozzles;

[0028] Each nozzle is numbered sequentially.

[0029] In some embodiments, determining whether the spray state detection of all nozzles is qualified includes:

[0030] Based on the imaging results of the nozzle's ejection state, determine whether the nozzle is ejecting.

[0031] If the imaging result of the nozzle shows an image of the jet stream, then the nozzle is qualified; otherwise, the nozzle is unqualified.

[0032] In some embodiments, determining whether the spray state detection of all nozzles is qualified includes:

[0033] The diameter of the jet stream is measured based on the imaging results of the jet state of the nozzle;

[0034] If the diameter of the jet stream from the nozzle is within the preset standard diameter range, the nozzle is qualified; otherwise, the nozzle is unqualified.

[0035] In some embodiments, determining whether the spray state detection of all nozzles is qualified includes:

[0036] Based on the imaging results of the jet state of the nozzle, the deflection angle of the jet flow relative to the vertical direction is measured;

[0037] If the deflection angle of the jet stream from the nozzle is within the preset standard angle range, the nozzle is qualified; otherwise, the nozzle is unqualified.

[0038] In some embodiments, the standard ratio includes 5%.

[0039] In some embodiments, the method for cleaning the printhead further includes cleaning the printhead in a cleaning environment;

[0040] The cleaning environment includes an inert gas environment.

[0041] The beneficial effects of the technical solution provided in this application include:

[0042] This application provides a method for cleaning a printhead. The method first determines the location of each nozzle by imaging the spray surface of the printhead, and then conveniently and accurately images the spraying state of each nozzle sequentially. The nozzles are numbered to clearly identify the nozzle number corresponding to each location, facilitating quick location of the corresponding nozzle. During printhead cleaning, the printhead is first sprayed with cleaning fluid for a preset cleaning time. At this point, the printhead completes the first stage of cleaning, and the printhead flow channel and nozzles are basically cleaned. Subsequently, the printhead continues to spray, and during spraying, the spraying state of each nozzle is sequentially imaged and detected, resulting in high detection efficiency for nozzle cleaning.

[0043] Furthermore, as multiple nozzles of the printhead are inspected sequentially, on the one hand, nozzles that are later in the inspection sequence continue to be cleaned to improve the cleaning effect of subsequent nozzles; on the other hand, nozzles that have been imaged and inspected continue to be cleaned. Therefore, even if a nozzle fails the cleaning test, as subsequent nozzles are inspected sequentially, the nozzles that failed the cleaning test continue to be cleaned and are more likely to change from unqualified to qualified. Thus, the actual effect of printhead cleaning is better than the effect of printhead inspection, ensuring the cleaning quality of the printhead and ensuring that the printhead meets printing requirements.

[0044] In addition, since all nozzles are numbered, after nozzle inspection, the location and number of all defective nozzles can be determined, which facilitates the quick location of defective nozzles and their re-cleaning and inspection, thereby improving inspection efficiency and repeat cleaning efficiency.

[0045] Compared to existing technologies, this cleaning method avoids wasting functional fluid during cleaning effect testing, thus saving costs. Furthermore, during printhead cleaning, it facilitates quick and easy identification of unsatisfactory nozzles. After repeated cleaning, it allows for rapid and accurate localization of these unsatisfactory nozzles, improving testing efficiency and shortening preparation time for printing. Moreover, simultaneous cleaning and testing not only enhances testing efficiency but also ensures that the actual cleaning effect is reflected in the testing results, guaranteeing cleaning quality and ensuring the printhead meets printing requirements.

[0046] Secondly, a cleaning device for a printhead is provided, comprising:

[0047] Installation mechanism, the installation mechanism being used to install the nozzle;

[0048] The detection mechanism is used to image and detect the spray surface of the nozzle and to detect the jet stream ejected from the nozzle;

[0049] A motion mechanism that drives the detection mechanism to move relative to the length direction of the nozzle;

[0050] A control system that controls the mounting mechanism, the detection mechanism, and the motion mechanism according to the cleaning method for the inkjet printhead described above.

[0051] Another embodiment of this application provides a cleaning device for a printhead. Since the cleaning device for a printhead is controlled based on the above-described cleaning method for a printhead, the beneficial effects of the cleaning device for a printhead are the same as those of the above-described cleaning method for a printhead, and will not be repeated here. Attached Figure Description

[0052] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0053] Figure 1 A flowchart illustrating a method for cleaning a printhead provided in an embodiment of this application;

[0054] Figure 2 A schematic diagram showing the jet diameter and standard diameter provided in the embodiments of this application;

[0055] Figure 3 This is a schematic diagram showing that the jet stream has an angle with the vertical direction, as provided in the embodiments of this application. Detailed Implementation

[0056] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0057] This application provides a method and apparatus for cleaning printheads for inkjet printing. The cleaning method involves spraying cleaning fluid onto the printhead, and imaging detection during nozzle ejection to determine if the cleaning is satisfactory. The ejection state of each nozzle is sequentially imaged and the number of any defective nozzles is recorded for further rapid processing. Therefore, the cleaning and detection efficiency is high, the print preparation time is short, and the cleaning effect is guaranteed, meeting the needs of inkjet printing. This application addresses the following technical problems in related technologies: firstly, it leads to waste of functional fluid, increasing costs; secondly, it results in long print preparation times, reducing processing efficiency; and thirdly, if a test print fails, the printhead needs to be cleaned again, severely impacting the printing progress.

[0058] Reference Figure 1 A method for cleaning a printhead for inkjet printing includes the following steps:

[0059] S100, Imaging the spray surface of the nozzle.

[0060] S200, calibrate the position of all nozzles and number all nozzles.

[0061] S300: Supply cleaning fluid to the nozzle and spray the cleaning fluid for a preset cleaning time.

[0062] S400: Continue spraying cleaning fluid from the nozzle, and sequentially perform imaging detection on the spraying status of all nozzle holes.

[0063] S500: Determine whether the spraying status of all nozzles is qualified, and count the number of unqualified nozzles and record the numbers of unqualified nozzles.

[0064] S600: Determine whether the proportion of unqualified nozzles does not exceed the standard proportion.

[0065] S700: If the proportion of unqualified nozzles does not exceed the standard proportion, then the nozzle cleaning is completed.

[0066] S800 If the proportion of unqualified nozzles exceeds the standard proportion, the nozzle re-washing step shall be performed until the proportion of unqualified nozzles does not exceed the standard proportion.

[0067] This setup determines the location of each nozzle by imaging the spray surface of the nozzle, allowing for convenient and precise sequential imaging of the spraying status of each nozzle. The nozzles are also numbered to clearly identify the nozzle number corresponding to each location, facilitating quick identification of the corresponding nozzle. During nozzle cleaning, the nozzle first sprays cleaning fluid for a preset cleaning time, completing the first stage of cleaning, essentially cleaning the nozzle flow channel and nozzles. Spraying continues, and during spraying, the spraying status of each nozzle is sequentially imaged and detected, resulting in high detection efficiency for nozzle cleaning.

[0068] Furthermore, as multiple nozzles of the printhead are inspected sequentially, on the one hand, nozzles that are later in the inspection sequence continue to be cleaned to improve the cleaning effect of subsequent nozzles; on the other hand, nozzles that have been imaged and inspected continue to be cleaned. Therefore, even if a nozzle fails the cleaning test, as subsequent nozzles are inspected sequentially, the nozzles that failed the cleaning test continue to be cleaned and are more likely to change from unqualified to qualified. Thus, the actual effect of printhead cleaning is better than the effect of printhead inspection, ensuring the cleaning quality of the printhead and ensuring that the printhead meets printing requirements.

[0069] In addition, since all nozzles are numbered, after nozzle inspection, the location and number of all defective nozzles can be determined, which facilitates the quick location of defective nozzles and their re-cleaning and inspection, thereby improving inspection efficiency and repeat cleaning efficiency.

[0070] Compared to existing technologies, this cleaning method avoids wasting functional fluid during cleaning effect testing, thus saving costs. Furthermore, during printhead cleaning, it facilitates quick and easy identification of unsatisfactory nozzles. After repeated cleaning, it allows for rapid and accurate localization of these unsatisfactory nozzles, improving testing efficiency and shortening preparation time for printing. Moreover, simultaneous cleaning and testing not only enhances testing efficiency but also ensures that the actual cleaning effect is reflected in the testing results, guaranteeing cleaning quality and ensuring the printhead meets printing requirements.

[0071] Step S100 involves imaging the spray surface of the nozzle. Specifically:

[0072] A high-magnification camera is used to scan and image the spray surface of the nozzle in order to determine the state of the spray surface.

[0073] This setup allows for a clearer view of the nozzle's spray surface and the condition of each nozzle hole using a high-magnification camera.

[0074] Step S200 involves marking the positions of all nozzles and numbering them. Specifically, this includes steps S210 and S220.

[0075] S210. Record the spacing of all nozzles along the length of the nozzle head, and record the position of the nozzles at the edge, so as to know the position of all nozzles.

[0076] S220. Number each nozzle sequentially.

[0077] This setup, by calibrating the positions of all nozzles, allows for quick and accurate positioning of different nozzles within the imaging field of view during subsequent sequential imaging inspections of their spray patterns, improving both inspection efficiency and accuracy. Furthermore, by numbering all nozzles, the numbers of those that passed cleaning and those that failed can be identified. This facilitates direct location and inspection of the failed nozzles during subsequent re-cleaning processes, further enhancing cleaning inspection efficiency.

[0078] In step S210, the spacing of all nozzles along the length of the nozzle head is recorded, as well as the positions of the nozzles at the edges, to determine the positions of all nozzles. Specifically:

[0079] When using a high-magnification camera to image the spray surface of a nozzle, the distance between the nozzles can be determined based on the movement of the high-magnification camera or the nozzle, thus identifying the position of each nozzle. By moving the high-magnification camera relative to the nozzle along the length of its spray surface, the nozzles located at the edge of the spray surface can be identified.

[0080] This setup, utilizing imaging, makes it easier and more accurate to determine the location of each nozzle, including those at the edges. Subsequent nozzle inspections proceed sequentially along the length of the spray surface, starting with the nozzles at the edges as the first to be inspected, thus reducing the chance of missed detections.

[0081] In step S220, each nozzle is numbered sequentially. Specifically:

[0082] Based on the direction of sequential detection of all nozzles, multiple nozzles are numbered sequentially. That is, the nozzle located at one edge along the length of the spray surface is numbered 1, and subsequent nozzles are numbered 2, 3, 4, and so on. Alternatively, a binary numbering mode can be used to sequentially number the nozzles to facilitate data transmission.

[0083] This setup allows for easy identification of nozzles by numbering the nozzles and then assigning each nozzle a corresponding cleaning pass / fail status during subsequent nozzle cleaning checks. For example, nozzle 1, indicating a pass / fail status, is marked as OK; nozzle 3, indicating a fail / fail status, is marked as NG. The location of the NG nozzles can then be quickly identified using their numbers, thus accelerating the nozzle rewashing process.

[0084] In step S300, cleaning fluid is supplied to the nozzle and the nozzle sprays cleaning fluid for a preset cleaning time. Specifically:

[0085] After supplying cleaning fluid to the nozzle, the nozzle is continuously operated to flush the internal flow channels and nozzle walls with the cleaning fluid, thus cleaning the nozzle. In this embodiment, the cleaning time ranges from 30 seconds to 5 minutes.

[0086] This design effectively flushes out solutes adhering to the nozzle flow channel and nozzle orifice walls by the flow of cleaning fluid inside the nozzle and by spraying the cleaning fluid out.

[0087] In step S400, the nozzle continues to spray cleaning fluid, and the spraying status of all nozzle holes is sequentially imaged and detected. Specifically:

[0088] A high-magnification camera is used to image and detect the jet stream ejected from the nozzle. The imaging results are used to determine whether the jet state of the nozzle is up to standard, so as to determine whether the cleaning of the nozzle is up to standard.

[0089] By determining the position of each nozzle, the required distance for the high-magnification camera to move each time can be known, enabling precise imaging and detection of the spraying state of the next nozzle. This improves the efficiency of detection alignment and reduces the likelihood of missing nozzles.

[0090] This setup, as the printhead sprays cleaning fluid, simultaneously images and detects the spraying status of each nozzle, improving the efficiency of cleaning effect detection. Furthermore, as multiple nozzles are sequentially detected, nozzles later in the detection sequence continue to be cleaned to improve their cleaning effect; simultaneously, nozzles that have already been imaged and detected continue to be cleaned. Therefore, even if a nozzle fails the initial cleaning test, the continued cleaning process as subsequent nozzles are detected makes it easier for those that failed to pass to improve. Thus, the actual cleaning effect of the printhead is better than the detection effect, ensuring the cleaning quality of the printhead and guaranteeing that it meets printing requirements.

[0091] In other embodiments, when testing the cleaning effect of the printhead, the printhead simulates the printing state during operation and sprays cleaning fluid at intervals.

[0092] In this embodiment, the spraying status of multiple nozzles is detected sequentially, and during the spraying interval of the nozzle, the spraying location of the next nozzle to be imaged and detected is moved into the imaging field of view.

[0093] This setup simulates the spraying state of the nozzle during operation, making the cleaning results more reliable. Furthermore, switching between different nozzles during the spray interval allows for simultaneous switching of detection positions while spraying, thus improving detection efficiency.

[0094] In step S500, the spraying status of all nozzles is determined to be qualified, and the number of unqualified nozzles is counted and their numbers are recorded. Specifically:

[0095] The spray state of the nozzle includes one or more of the following: whether the nozzle is spraying, the diameter of the spray stream, and the angle of the spray stream relative to the vertical direction. In this embodiment, the spray state of the nozzle includes whether the nozzle is spraying, the diameter of the spray stream, and the angle of the spray stream relative to the vertical direction. That is, all three of these requirements must be met for the nozzle to be deemed to have passed the cleaning test.

[0096] After determining whether the nozzles have passed the cleaning test, the numbers of the unqualified nozzles are recorded simultaneously, and the total number of unqualified nozzles is counted.

[0097] This setup allows for the determination of the percentage of defective nozzles by counting the total number of defective nozzles, facilitating subsequent assessment of whether the overall nozzle cleaning process is satisfactory. Recording the numbers of defective nozzles also allows for quick location of them when re-cleaning the nozzles, improving inspection efficiency.

[0098] The determination of whether the spraying status of all nozzles is qualified includes:

[0099] Based on the imaging results of the nozzle's spray pattern, determine whether the nozzle is spraying.

[0100] If the imaging result of the nozzle shows an image of the jet stream, then the nozzle is qualified; otherwise, the nozzle is unqualified.

[0101] With this setup, the nozzle positions are clearly marked, allowing the spraying area of ​​the nozzle to be inspected to be moved into the imaging field of view. If the nozzle does not spray at this point, it indicates that the nozzle is blocked and has not been properly cleaned. Therefore, even if the nozzle does not spray, there will be no missed detection of the nozzle cleaning effect.

[0102] Reference Figure 2 The determination of whether the spray status of all nozzles is qualified includes:

[0103] The diameter of the jet stream is measured based on the imaging results of the jet state of the nozzle.

[0104] If the deviation between the jet diameter and the standard diameter of the nozzle is within the preset standard diameter deviation range, the nozzle is qualified; otherwise, the nozzle is unqualified.

[0105] Specifically, under normal conditions, the diameter of the jet stream is the standard diameter. The standard diameter can also be determined based on the standard parameters of the nozzle. Alternatively, it can be obtained by measuring the diameters of the jet streams from multiple unclogging nozzles and taking the average value.

[0106] The deviation between the jet diameter and the standard diameter of the nozzle is calculated as follows: the jet diameter is d, the standard diameter is D, and the deviation between the jet diameter and the standard diameter is a = (dD) / D*100%.

[0107] In this embodiment, the standard diameter deviation range includes ±5%. That is, if the deviation of the jet diameter from the standard diameter is not within ±5%, the jet is unqualified. If the deviation of the jet diameter from the standard diameter is within ±5%, the jet is qualified.

[0108] This setup allows for easy measurement of the jet stream diameter through imaging. If the jet stream diameter is too large, it may indicate nozzle damage; if it is too small, it may suggest partial blockage. Measuring the jet stream diameter allows for detection of partial nozzle blockage, thus improving the accuracy of nozzle cleaning status assessment.

[0109] Reference Figure 3 The determination of whether the spray status of all nozzles is qualified includes:

[0110] Based on the imaging results of the jet's ejection state, the angle of deviation of the jet stream relative to the vertical direction is measured.

[0111] If the deflection angle of the jet flow of the nozzle hole is within the preset standard angle range, the nozzle hole is qualified; otherwise, the nozzle hole is unqualified.

[0112] Specifically, by analyzing the image of the jet flow ejected from the nozzle hole, the deflection angle between the center line of the jet flow and the vertical direction is measured. In this embodiment, the standard angle range includes not greater than 10 degrees. When the deflection angle between the center line of the jet flow and the vertical direction is greater than 10 degrees, the cleaning of the nozzle hole is unqualified. When the deflection angle between the center line of the jet flow and the vertical direction is less than or equal to 10 degrees, the cleaning of the nozzle hole is qualified.

[0113] With this setting, when the nozzle hole is partially blocked, the ejection direction of the jet flow ejected from the nozzle hole will change. Therefore, it is possible to judge whether the nozzle hole is cleaned qualified according to the ejection direction of the jet flow.

[0114] In this embodiment, the nozzle hole needs to eject a jet flow, and the deviation between the diameter of the jet flow of the nozzle hole and the standard diameter is within ±5%, and the deflection angle between the center line of the jet flow and the vertical direction is less than or equal to 10 degrees. At this time, the cleaning of the nozzle hole is qualified.

[0115] With this setting, by imaging and detecting various ejection states of the nozzle hole, it is ensured that the nozzle hole is cleaned in place, so as to ensure the quality of the nozzle used for inkjet printing and ensure the quality of inkjet printing.

[0116] In other embodiments, it is also possible to meet only one of the conditions that the deviation between the diameter of the jet flow of the nozzle hole and the standard diameter is within ±5% and the deflection angle between the center line of the jet flow and the vertical direction is less than or equal to 10 degrees, which indicates that the nozzle hole is cleaned in place.

[0117] Among them, in step S600, it is judged whether the proportion of unqualified nozzle holes does not exceed the standard proportion. Specifically:

[0118] According to the total number of unqualified nozzle holes and the total number of nozzle holes, the proportion of unqualified nozzle holes can be obtained. In this embodiment, the standard proportion includes 5%. In other embodiments, the standard proportion can also include 1%, 2%, 3%, 4%, 6%, 7%, 8%, 9%, 10%...

[0119] Among them, in step S700, if the proportion of unqualified nozzle holes does not exceed the standard proportion, the cleaning of the nozzle is completed. Specifically:

[0120] When the proportion of unqualified nozzle holes is less than or equal to the standard proportion, at this time, the cleaning of the nozzle is qualified, and the cleaning of the nozzle is completed at this time. The cleaned nozzle meets the requirements of inkjet printing.

[0121] Among them, in step S800, if the proportion of unqualified nozzle holes exceeds the standard proportion, the nozzle re-cleaning step is performed until the proportion of unqualified nozzle holes does not exceed the standard proportion. Specifically:

[0122] When the proportion of defective nozzles exceeds the standard proportion, the excessive number of defective nozzles can negatively impact the printing process. In this case, a printhead re-cleaning step should be performed until the proportion of defective nozzles does not exceed the standard proportion.

[0123] Specifically: The nozzle rewashing process includes steps S810-S840.

[0124] S810, causes the nozzle to spray cleaning fluid for a preset rewash time.

[0125] S820, then continue spraying cleaning fluid from the nozzle and perform imaging detection on different defective nozzles.

[0126] S830. Count the number of remaining defective nozzles and record their numbers.

[0127] S840. Determine whether the percentage of remaining unqualified nozzles does not exceed the standard percentage.

[0128] Based on the determination of the proportion of unqualified nozzles, there are two possible scenarios.

[0129] 1. If the proportion of remaining unqualified nozzles does not exceed the standard proportion, the nozzle is considered cleaned.

[0130] 2. If the proportion of remaining unqualified nozzles is still greater than the standard proportion, the nozzle will continue to spray cleaning fluid, and imaging detection will be performed on different unqualified nozzles until the proportion of remaining unqualified nozzles does not exceed the standard proportion.

[0131] This setup, by re-washing the nozzles and extending the cleaning time, thoroughly rinses the nozzle flow channels and orifice walls, removing solutes adhering to them. After re-washing, since the numbers of the defective nozzles are known, the qualified nozzles can be skipped, and the defective nozzles can be directly inspected, improving inspection efficiency.

[0132] In step S810, the nozzle sprays cleaning fluid for a preset rewash time. Specifically:

[0133] The rewash time ranges from 30 seconds to 5 minutes. The nozzles can spray continuously or in short bursts.

[0134] In step S820, the nozzle continues to spray cleaning fluid, and imaging detection is performed on different defective nozzles. Specifically:

[0135] The nozzle continues to spray cleaning fluid, and a high-magnification camera sequentially images and inspects the spraying status of any defective nozzles. The imaging inspection of defective nozzles specifically includes:

[0136] Locate the positions of multiple defective nozzles based on their numbers.

[0137] Based on the location of multiple defective nozzles, imaging detection is performed on multiple defective nozzles sequentially.

[0138] With this setup, the position of each nozzle is marked and corresponds to its number. The nozzle position can be matched by the number, which facilitates the quick location of defective nozzles. A high-magnification camera can be used to image the defective nozzles directly, enabling rapid and accurate imaging and detection of defective nozzles after rewashing, thus improving cleaning and inspection efficiency.

[0139] Specifically, step S830 involves counting the number of remaining defective nozzles and recording their numbers.

[0140] After rewashing the printhead and re-inspecting the defective nozzles, continue to record the numbers of the remaining defective nozzles and count their quantity. This is to determine whether the printhead was thoroughly cleaned after rewashing, and to facilitate rapid location and inspection of the remaining defective nozzles after rewashing the printhead.

[0141] In step S840, it is determined whether the proportion of the remaining unqualified nozzles does not exceed the standard proportion.

[0142] Specifically, after comparing the proportion of remaining substandard nozzles with the standard proportion, two situations emerge:

[0143] 1. If the proportion of remaining unqualified nozzles does not exceed the standard proportion, the nozzle is considered cleaned.

[0144] Therefore, if the proportion of defective nozzles after re-washing does not exceed the standard proportion, the printhead cleaning is complete and meets the printing processing requirements.

[0145] 2. If the proportion of remaining unqualified nozzles is still greater than the standard proportion, the nozzle will continue to spray cleaning fluid, and imaging detection will be performed on different unqualified nozzles until the proportion of remaining unqualified nozzles does not exceed the standard proportion.

[0146] Therefore, if the nozzle is still not cleaned properly after the re-washing, it will be re-washed again. After each re-washing, the corresponding unqualified nozzles are inspected, resulting in high inspection efficiency.

[0147] Optionally, the cleaning method for the inkjet printhead further includes step S900 and a primary screening printhead, wherein the primary screening printhead specifically includes:

[0148] Based on the imaging results of the spray surface, the proportion of defective spray holes out of the total number of defective spray holes was determined.

[0149] If the non-compliance rate is less than the preset replacement rate, then the positions of all nozzles are calibrated and all nozzles are numbered; otherwise,

[0150] Replace the nozzle.

[0151] With this setting, if the total number of unqualified nozzles in the initial screening is too high, it indicates that the nozzle does not need to be cleaned, thus avoiding wasting the time required for cleaning.

[0152] Specifically, after the high-magnification camera images the spray surface of the nozzle, the imaging results of the nozzle position can be used to preliminarily determine the clogging status of the nozzle. After processing all the clogging nozzles, the total number of unqualified nozzles in the initial screening can be obtained.

[0153] The replacement ratio ranges from 20% to 60%, and in this embodiment, the replacement ratio includes 30%.

[0154] When the total number of defective nozzles is greater than or equal to the replacement ratio of the total number of nozzles, the cleaning of the nozzles should be abandoned and other nozzles should be replaced.

[0155] When the proportion of the total number of defective nozzles to the total number of nozzles is less than the replacement ratio, step S200 can be performed to mark the position of all nozzles and number all nozzles.

[0156] The cleaning method for the printhead also includes cleaning the printhead in a cleaning environment. The cleaning environment includes an inert gas environment. In this embodiment, the inert gas environment includes a nitrogen environment.

[0157] This setup controls the cleaning environment to prevent external contamination of the nozzles. It also prevents residual functional liquid inside the nozzles from evaporating and polluting the surrounding environment during cleaning.

[0158] This application provides a method for cleaning a printhead. The method first determines the location of each nozzle by imaging the spray surface of the printhead, and then conveniently and accurately images the spraying state of each nozzle sequentially. The nozzles are numbered to clearly identify the nozzle number corresponding to each location, facilitating quick location of the corresponding nozzle. During printhead cleaning, the printhead is first sprayed with cleaning fluid for a preset cleaning time. At this point, the printhead completes the first stage of cleaning, and the printhead flow channel and nozzles are basically cleaned. Subsequently, the printhead continues to spray, and during spraying, the spraying state of each nozzle is sequentially imaged and detected, resulting in high detection efficiency for nozzle cleaning.

[0159] Furthermore, as multiple nozzles of the printhead are inspected sequentially, on the one hand, nozzles that are later in the inspection sequence continue to be cleaned to improve the cleaning effect of subsequent nozzles; on the other hand, nozzles that have been imaged and inspected continue to be cleaned. Therefore, even if a nozzle fails the cleaning test, as subsequent nozzles are inspected sequentially, the nozzles that failed the cleaning test continue to be cleaned and are more likely to change from unqualified to qualified. Thus, the actual effect of printhead cleaning is better than the effect of printhead inspection, ensuring the cleaning quality of the printhead and ensuring that the printhead meets printing requirements.

[0160] In addition, since all nozzles are numbered, after nozzle inspection, the location and number of all defective nozzles can be determined, which facilitates the quick location of defective nozzles and their re-cleaning and inspection, thereby improving inspection efficiency and repeat cleaning efficiency.

[0161] Compared to existing technologies, this cleaning method avoids wasting functional fluid during cleaning effect testing, thus saving costs. Furthermore, during printhead cleaning, it facilitates quick and easy identification of unsatisfactory nozzles. After repeated cleaning, it allows for rapid and accurate localization of these unsatisfactory nozzles, improving testing efficiency and shortening preparation time for printing. Moreover, simultaneous cleaning and testing not only enhances testing efficiency but also ensures that the actual cleaning effect is reflected in the testing results, guaranteeing cleaning quality and ensuring the printhead meets printing requirements.

[0162] Another embodiment of this application provides a cleaning device for a printhead, comprising:

[0163] The mounting mechanism is used to install the nozzles;

[0164] Testing agencies are used to image and inspect the spray surface of nozzles and to inspect the jet stream ejected from the nozzles.

[0165] The motion mechanism drives the detection mechanism to move relative to the length of the nozzle.

[0166] The control system controls the mounting mechanism, detection mechanism, and motion mechanism according to the above-described method for cleaning the printhead.

[0167] Another embodiment of this application provides a cleaning device for a printhead. Since the cleaning device for a printhead is controlled based on the above-described cleaning method for a printhead, the beneficial effects of the cleaning device for a printhead are the same as those of the above-described cleaning method for a printhead, and will not be repeated here.

[0168] In the description of this application, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0169] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0170] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for cleaning a printhead for inkjet printing, characterized in that, It includes the following steps: Image the spray surface of the nozzle; Mark the location of all nozzles and number all nozzles; Supply cleaning fluid to the nozzle and make the nozzle spray cleaning fluid for a preset cleaning time; The nozzle continues to spray cleaning fluid, and the spraying status of all nozzle holes is imaged and detected in turn. Determine whether the spraying status of all nozzles is qualified, and count the number of unqualified nozzles and record their numbers. If the proportion of unqualified nozzles does not exceed the standard proportion, the nozzle cleaning is completed. If the proportion of defective nozzles exceeds the standard proportion, the nozzle is rewashed. The rewashing includes: spraying cleaning fluid into the nozzle for a preset rewashing time; then continuing to spray cleaning fluid into the nozzle and performing imaging detection on different defective nozzles; counting the number of remaining defective nozzles and recording their numbers; if the proportion of remaining defective nozzles is still greater than the standard proportion, the process of continuing to spray cleaning fluid into the nozzle and performing imaging detection on different defective nozzles is repeated until the proportion of remaining defective nozzles does not exceed the standard proportion. The step of continuing to spray cleaning fluid from the nozzle and performing imaging detection on different defective nozzles includes: locating the positions of multiple defective nozzles according to their numbers; and sequentially performing imaging detection on the multiple defective nozzles according to their positions.

2. The method for cleaning a printhead according to claim 1, characterized in that, After imaging the spray surface of the nozzle, a primary screening nozzle is also included, which includes: Based on the imaging results of the spray surface, the proportion of defective spray holes to the total number of defective spray holes was determined. If the non-compliance ratio is less than the preset replacement ratio, then the positions of all nozzles are calibrated and all nozzles are numbered. Otherwise, replace the nozzle.

3. The method for cleaning a printhead according to claim 1, characterized in that, The process of marking the positions of all nozzles and numbering all nozzles includes: Record the spacing of all nozzles along the length of the nozzle head, and record the position of the nozzles at the edge, in order to determine the position of all nozzles; Each nozzle is numbered sequentially.

4. The method for cleaning a printhead according to claim 1, characterized in that, The determination of whether the spray status detection of all nozzles is qualified includes: Based on the imaging results of the nozzle's ejection state, determine whether the nozzle is ejecting. If the imaging result of the nozzle shows an image of the jet stream, then the nozzle is qualified; otherwise, the nozzle is unqualified.

5. The method for cleaning a printhead according to claim 4, characterized in that, The determination of whether the spray status detection of all nozzles is qualified includes: The diameter of the jet stream is measured based on the imaging results of the jet state of the nozzle; If the diameter of the jet stream from the nozzle is within the preset standard diameter range, the nozzle is qualified; otherwise, the nozzle is unqualified.

6. The method for cleaning a printhead according to claim 1, 4, or 5, characterized in that, The determination of whether the spray status detection of all nozzles is qualified includes: Based on the imaging results of the jet state of the nozzle, the deflection angle of the jet flow relative to the vertical direction is measured; If the deflection angle of the jet stream from the nozzle is within the preset standard angle range, the nozzle is qualified; otherwise, the nozzle is unqualified.

7. The method for cleaning a printhead according to claim 1, characterized in that, The standard ratio includes 5%.

8. The method for cleaning a printhead according to claim 1, characterized in that, This also includes cleaning the nozzles in a cleaning environment; The cleaning environment includes an inert gas environment.

9. A cleaning device for a printhead used in inkjet printing, characterized in that, include: Installation mechanism, the installation mechanism being used to install the nozzle; The detection mechanism is used to image and detect the spray surface of the nozzle and to detect the jet stream ejected from the nozzle; A motion mechanism that drives the detection mechanism to move relative to the length direction of the nozzle; A control system that controls the mounting mechanism, the detection mechanism, and the motion mechanism according to the cleaning method for the printhead according to any one of claims 1 to 8.

Images