A nozzle clogging rapid detection device of a print head, printing equipment

Abstract

This application relates to the field of inkjet printing equipment technology, and in particular to a rapid nozzle clogging detection device for a printhead and a printing device. The device includes: an infrared laser generating unit for generating infrared laser; a spot detection unit for detecting the spot signal formed by the infrared laser; a translation mechanism for driving the infrared laser generating unit and the spot detection unit to translate synchronously along the nozzle row arrangement direction so that the path of the infrared laser is adapted to the target nozzle row; and a clogging detection unit for controlling the translation mechanism so that the path of the infrared laser is located in a plane jointly determined by the extension direction of the target nozzle row and the direction perpendicular to the target nozzle row on the ejection side, and the path of the infrared laser is parallel to the extension direction of the target nozzle row. Furthermore, when an ejection command is issued to the printhead to drive the nozzles of the target nozzle row to eject sequentially, the device determines the clogging position and number of clogging points in the target nozzle row based on the spot signal formed on the detection plane.

Description

Technical Field

[0001] This application relates to the field of inkjet printing equipment technology, and in particular to a rapid detection device for nozzle clogging of a printhead and a printing device. Background Technology

[0002] In the field of inkjet printing technology, a printhead typically consists of multiple nozzles arranged in a linear array. During operation, each nozzle ejects ink droplets sequentially according to a preset time sequence to complete the printing task of images or characters. As inkjet printing equipment develops towards higher speeds and higher precision, nozzle clogging has gradually become one of the key factors affecting print quality and equipment stability.

[0003] Existing technologies for detecting nozzle clogging typically include methods based on point-by-point detection of individual nozzles, offline detection methods based on image acquisition, or indirect judgment methods based on print result feedback. For example, some solutions determine whether a nozzle is clogged by observing the ejection state of a single nozzle during printing or by scanning the image on the print medium. However, these methods generally suffer from low detection efficiency and poor real-time performance, especially in printheads with a large number of nozzles, making it difficult to meet the needs of rapid detection.

[0004] Furthermore, while some existing optical detection schemes can observe the light spots formed during the spraying process using optical sensors, due to the spatial distribution characteristics of the nozzle array and the high-speed temporal characteristics of the spraying process, the detection system can usually only perform point-by-point scanning detection on a single nozzle or a local nozzle area. This makes it difficult to cover the complete spraying state information of the entire row of nozzles in a single detection cycle. Clearly, nozzle clogging detection schemes in related technologies generally rely on sequential nozzle-by-nozzle detection or local area scanning detection methods. This requires multiple re-alignment or scanning operations during the detection process, which not only increases detection time but is also susceptible to timing and spatial alignment errors during high-speed nozzle spraying, thus reducing detection accuracy. Simultaneously, the insufficient ability to synchronously acquire the overall state of the nozzle array makes it impossible to quickly determine the location and number of clogging nozzles in the entire row within a single spraying cycle, further limiting the efficiency of nozzle clogging detection. Summary of the Invention

[0005] (a) Technical problems to be solved

[0006] In view of the above-mentioned shortcomings and deficiencies of the prior art, this application provides a rapid detection device for nozzle clogging of printhead and a printing device, which solves the technical problems of low detection efficiency caused by the inability to simultaneously detect the entire row of nozzles in a single spraying process and the need for nozzle-by-nozzle scanning or multiple alignments during the detection process.

[0007] (II) Technical Solution

[0008] To achieve the above objectives, the main technical solutions adopted in this application include:

[0009] In a first aspect, embodiments of this application provide a rapid nozzle clogging detection device for a printhead, comprising: an infrared laser generating unit for generating a parallel infrared laser beam along the extension line of a nozzle row of the printhead; a spot detection unit for detecting a spot signal formed by the infrared laser on a detection plane aligned with the normal direction of the target nozzle row; a translation mechanism for driving the infrared laser generating unit and the spot detection unit to translate synchronously along the nozzle row arrangement direction so that the path of the infrared laser adapts to the target nozzle row; and a clogging detection unit for controlling the translation mechanism so that the path of the infrared laser lies in a plane jointly determined by the extension direction of the target nozzle row and the direction perpendicular to the target nozzle row on the spray side, and the path of the infrared laser is parallel to the extension direction of the target nozzle row; and, when a spray command is issued to the printhead to drive the nozzles of the target nozzle row to spray sequentially according to a first preset spray time interval, determining the clogging position and number of clogging points in the target nozzle row based on the spot signal formed on the detection plane.

[0010] Optionally, in some embodiments of this application, determining the position and number of plugs in the target nozzle row based on the light spot signal formed on the detection plane includes: acquiring a first light spot signal, and determining the position and number of plugs in the target nozzle row based on the first light spot signal; the first light spot signal is acquired at a second preset time interval after the injection command is issued.

[0011] Optionally, in some embodiments of this application, the infrared laser generated by the infrared laser generation unit has a wavelength range of 750nm to 3000nm, the cross-section of the infrared laser is circular or rectangular, and the coverage area of ​​the light spot formed by the infrared laser on the detection plane is greater than the overall distribution range of the ink droplets formed by each nozzle in the target nozzle row on the detection plane, so that the image of the light spot can simultaneously include the imaging of the ink droplets ejected by each nozzle in the target nozzle row.

[0012] Optionally, in some embodiments of this application, the second preset time interval includes: the time from when the printhead receives the ejection command until all ink droplets formed by sequential ejection from each nozzle in the target nozzle row enter the detection area corresponding to the infrared laser path.

[0013] Optionally, in some embodiments of this application, determining the location and number of plugs in the target nozzle row based on the first spot signal specifically includes: extracting the edge information of each ink droplet image in the first spot signal to determine the center position of each ink droplet image; and determining the location and number of plugs in the target nozzle row based on the center position of each ink droplet image in the first spot signal.

[0014] Optionally, in some embodiments of this application, determining the clogging position and number of clogging points in the target nozzle row based on the center position of each ink droplet image in the first spot signal includes: acquiring the actual spacing sequence between the center positions of adjacent ink droplet images from bottom to top in the first spot signal; comparing each actual spacing with a preset normal spacing from bottom to top; determining that there are missing ink droplets in the ink droplet sequence interval corresponding to any actual spacing greater than the preset normal spacing; determining the number of missing ink droplets in the ink droplet sequence interval based on the ratio of the actual spacing to the preset normal spacing, and performing position completion processing in the ink droplet sequence interval to obtain a completed ink droplet sequence; determining the corresponding target nozzle according to the sequence number of the completed ink droplet in the completed ink droplet sequence and the arrangement order of the nozzles in the target nozzle row, and determining that the target nozzle is clogged, so as to obtain the clogging position and number of clogging points in the target nozzle row.

[0015] Optionally, in some embodiments of this application, determining the clogging position and number of clogging nozzles in the target nozzle row based on the center position of each ink droplet in the first spot signal includes: obtaining the center position of each ink droplet image in the image of the spot corresponding to the first spot signal in the spot image coordinate system corresponding to the detection plane; sorting the center positions of each ink droplet image according to their longitudinal coordinate values ​​from small to large, with the nozzle spray direction as the longitudinal positive direction of the spot image coordinate system, to obtain an ordered ink droplet position sequence; matching the center positions of each ink droplet image in the ink droplet position sequence with the predetermined theoretical spray longitudinal position interval corresponding to each nozzle to determine the nozzle number that has sprayed; wherein, the theoretical spray longitudinal position interval is the expected distribution range of ink droplets corresponding to each nozzle in the spot image coordinate system; determining the clogged nozzles according to the nozzle numbers corresponding to the theoretical spray longitudinal position intervals where the ink droplet image center positions are not matched; and counting the clogged nozzles to obtain the clogging position and number of clogging nozzles in the target nozzle row.

[0016] Optionally, in some embodiments of this application, determining the plug position and number of plugs in the target nozzle row based on the light spot signal formed on the detection plane includes: synchronously starting a timer when the target nozzle row receives the spray command; establishing a correspondence between the nozzle sequence number and the detection time interval based on the nozzle spray sequence and a first preset spray time interval, wherein for the nth nozzle, its corresponding detection time interval is determined to be: [t1+(n-1)t2-0.5t2, t1+(n-1)t2+0.5t2]; where t1 is a pre-acquired delay time and t2 is the first preset spray time interval; during the spray... During nozzle ejection, if the spot detection unit detects an ink droplet spot signal at the center of the spot signal within the detection time interval corresponding to the nth nozzle, the nth nozzle is determined to be a normal nozzle, and its blockage mark is set to normal. If the spot detection unit does not detect an ink droplet spot signal at the center of the spot signal within the corresponding detection time interval, the nth nozzle is determined to be a blocked nozzle, and its blockage mark is set to blocked. After determining all nozzles in the target nozzle row, the number of nozzles marked as blocked is counted to determine the number of blockages, and the blockage position is determined according to the number of the nozzles marked as blocked in the nozzle sequence.

[0017] Optionally, in some embodiments of this application, the method for obtaining the delay time t1 includes: selecting any nozzle in the target nozzle row as a calibration nozzle; sending a jet trigger signal to the calibration nozzle, and using the time of sending the jet trigger signal as the time starting point; recording the time when the spot detection unit detects the appearance of the ink droplet spot signal corresponding to the calibration nozzle at the center of the spot signal as the detection time, and calculating the time difference between the detection time and the time starting point, using the time difference as a delay measurement value; repeating the above measurement process multiple times to obtain multiple delay measurement values; and performing statistical processing on the multiple delay measurement values ​​to obtain an average value or a weighted average value, which is used as the delay time t1.

[0018] On the other hand, this embodiment also provides a printing device, including: a printhead; and a rapid detection device for nozzle clogging of the printhead as described above.

[0019] (III) Beneficial Effects

[0020] The nozzle clogging rapid detection device and printing equipment for the printhead provided in this application embodiment generate parallel infrared lasers by setting an infrared laser generation unit on the extension line of the nozzle row of the printhead, and combining it with a spot detection unit to collect the spot signal formed on the detection plane in real time. This allows the ink droplet spot generated during nozzle ejection to be stably captured in a unified spatial detection plane, thereby providing reliable raw observation data for nozzle status determination. Simultaneously, a translation mechanism drives the infrared laser generation unit and the spot detection unit to synchronously translate along the nozzle row arrangement direction, enabling the infrared laser path to self-adapt to the target nozzle row. Under the control of the clogging detection unit, the infrared laser path is stably located in a plane jointly determined by the extension direction of the target nozzle row and the direction perpendicular to the target nozzle row on the ejection side, and remains parallel to the extension direction of the target nozzle row. This achieves precise alignment between the detection optical path and the spatial structure of the nozzle array, avoiding spot acquisition errors caused by positional offsets.

[0021] Furthermore, after issuing a spray command to the print head to drive the target nozzle row nozzles to spray sequentially according to a first preset spray time interval, by establishing a spatiotemporal correspondence between the nozzle spraying process and the spot signal, the spraying behavior of each nozzle can form a distinguishable spot response sequence within the detection plane. Based on this spot signal, the target nozzle row is analyzed as a whole, thereby simultaneously determining the location and number of clogging nozzles during the unified detection process. Therefore, the embodiments of this application can achieve rapid overall identification of the nozzle status of the target nozzle row through synchronous adaptation of the infrared laser path and the nozzle row structure, as well as the corresponding mapping between the spraying sequence and the spot signal. Compared with the point-by-point scanning or local detection methods in the prior art, this application does not require multiple alignments or repeated scans, and can complete the determination of the clogging location and number of nozzles in the entire row in one spraying process, thereby significantly improving detection efficiency and enhancing the overall accuracy and stability of nozzle clogging detection. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of a rapid nozzle clogging detection device for a printhead according to an embodiment of this application;

[0023] Figure 2 This is a schematic diagram of the first light spot signal when all six nozzles are functioning normally, according to one embodiment of this application;

[0024] Figure 3 This is a schematic diagram of the first light spot signal in the case of blockage of the third nozzle in the target nozzle row according to one embodiment of this application;

[0025] Figure 4 This is a schematic diagram of a printing device according to an embodiment of the present application. Detailed Implementation

[0026] To better explain and facilitate understanding of this application, the following detailed description of the application is provided in conjunction with the accompanying drawings and specific embodiments.

[0027] In related technologies, the detection of printhead nozzle clogging can be mainly categorized into three types:

[0028] The first type is a detection scheme based on sequential nozzle detection or point-to-point scanning. This scheme typically uses a single detection sensor or local optical acquisition structure to perform individual nozzle ejection and point-by-point observation, and determines whether a blockage has occurred based on the ejection result of each individual nozzle. Although this scheme is relatively simple to implement, it requires sequential detection of each nozzle within a nozzle row, making it impossible to simultaneously acquire the ejection status information of the entire row of nozzles during a single ejection. This results in the detection process relying on multiple alignments and repeated scans, which not only leads to low detection efficiency but also easily introduces timing and spatial alignment errors under high-speed ejection conditions, thus affecting the accuracy of blockage location determination.

[0029] The second type is an indirect detection scheme based on printing results or media imaging feedback. This scheme analyzes the image quality or ink droplet distribution on the printing medium to infer whether the nozzle is clogged. However, this scheme relies on feedback after printing is completed, cannot obtain instantaneous information about the nozzle's state during the ejection process in real time, and is greatly affected by the medium's adsorption characteristics, diffusion effects, and environmental factors. This makes it difficult to accurately locate the nozzle clogging position, and it also cannot directly obtain information on the number of clogged nozzles, resulting in a strong detection lag.

[0030] The third type is the spray state recognition scheme based on local optical detection. Although this scheme introduces optical sensors to detect the light spot during the spraying process, due to the large spatial distribution range of the nozzle array, there is a lack of a stable spatial mapping relationship between the detection optical path and the nozzle row. It can usually only observe local areas or individual nozzles, making it difficult to cover the spraying process of the entire row of nozzles. At the same time, during the high-speed sequential spraying process of the nozzles, there is a lack of a unified spatiotemporal correspondence mechanism between the light spot signal and the nozzle number, making it difficult to directly correspond the detection results to the specific nozzle position, thus failing to achieve synchronous determination of the blockage position and number of the entire row of nozzles.

[0031] Obviously, the nozzle blockage detection schemes in related technologies generally have problems such as the need to scan point by point during the detection process, the inability to achieve synchronous detection of the entire row of nozzles in a single spraying process, and the lack of a stable correspondence between the light spot signal and the nozzle number. These problems result in low detection efficiency, insufficient positioning accuracy, and difficulty in obtaining complete blockage distribution information.

[0032] To address this, the printhead nozzle clogging rapid detection device provided in this application provides an infrared laser generation unit along the extension line of the nozzle row to generate parallel infrared lasers. A spot detection unit collects the spot signals formed within the detection plane in real time, enabling stable imaging of the ink droplet spots generated during nozzle ejection within a unified detection plane. Simultaneously, a translation mechanism drives the infrared laser generation unit and the spot detection unit to synchronously translate along the nozzle row arrangement direction, spatially adapting the infrared laser path to the target nozzle row. Under the control of the clogging detection unit, the infrared laser path remains stably located within the plane jointly determined by the nozzle row extension direction and its normal direction, maintaining a parallel relationship. This establishes a stable spatial mapping relationship between the nozzle row and the optical detection plane. Furthermore, during the sequential ejection of the target nozzle row nozzles according to a first preset ejection time interval, the nozzle ejection sequence is analyzed in correspondence with the spot signals within the detection plane. This allows the spot responses generated by different nozzles to be distinguished and matched under a unified time reference, thereby completing the analysis of the overall ejection state of the target nozzle row during a single ejection process and simultaneously determining the clogging position and number of nozzles. Therefore, compared with the point-by-point scanning or local detection methods in the prior art, the embodiments of this application can quickly and synchronously detect the entire row of nozzles in one spraying process, without the need for multiple alignments or repeated scanning, so as to quickly determine the location and number of blockages, thereby significantly improving detection efficiency and positioning accuracy, and enhancing the integrity and reliability of detection results.

[0033] To better understand the above technical solutions, exemplary embodiments of this application will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of this application are shown in the drawings, it should be understood that this application can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this application can be understood more clearly and thoroughly, and that the scope of this application can be fully conveyed to those skilled in the art.

[0034] Figure 1 This is a schematic diagram of a rapid nozzle clogging detection device for a printhead according to an embodiment of this application. Figure 1 As shown, the rapid nozzle clogging detection device for the printhead includes:

[0035] Infrared laser generating unit 1 is used to generate a parallel infrared laser 5 on the extension line of the nozzle row of the printhead 3;

[0036] The spot detection unit 2 is used to detect the spot signal formed by the infrared laser 5 on the detection plane that is consistent with the normal direction of the target nozzle row 4;

[0037] A translation mechanism is used to drive the infrared laser generating unit 1 and the spot detection unit 2 to translate synchronously along the nozzle row arrangement direction so that the path of the infrared laser 5 is adapted to the target nozzle row 4;

[0038] The blockage detection unit controls the translation mechanism to ensure that the path of the infrared laser 5 lies in a plane defined by the extension direction of the target nozzle row 4 and the direction perpendicular to the target nozzle row 4 on the spray side, and the path of the infrared laser 5 is parallel to the extension direction of the target nozzle row. When a spray command is sent to the print head 3 to drive the nozzles of the target nozzle row 4 to spray sequentially according to a first preset spray time interval, the unit determines the position and number of blockages in the target nozzle row 4 based on the light spot signal formed on the detection plane.

[0039] In one specific embodiment, taking a nozzle row in an inkjet printer as an example, the nozzle row is composed of multiple nozzles arranged at a linear, uniform spacing. During printing, each nozzle performs an ejection operation sequentially according to a first preset ejection time interval. An infrared laser generation unit 1 is arranged in the extension direction of the nozzle row of the printhead 3 and generates an infrared laser beam 5 parallel to the extension direction of the nozzle row. This infrared laser 5 passes through the nozzle ejection area and forms a stable optical path behind it. At the same time, a spot detection unit 2 is set on a detection plane aligned with the normal direction of the target nozzle row 4. It is used to receive the optical scattering or occlusion changes generated by the ink droplets 6 passing through the infrared laser during nozzle ejection, thereby forming a corresponding spot signal on the detection plane. For example, when the third nozzle normally ejects ink droplets 6 within its corresponding time window, the ink droplets 6 passing through the infrared laser 5 will form a spot response with obvious characteristics on the detection plane; while when a nozzle is clogged, no corresponding ink droplet spot signal will appear within its corresponding time window.

[0040] To ensure that the infrared laser 5 can be precisely aligned with nozzle rows at different positions, this application uses a translation mechanism to drive the infrared laser generation unit 1 and the spot detection unit 2 to move synchronously along the nozzle row arrangement direction, so that the spatial path of the infrared laser 5 can gradually cover the entire nozzle row area. For example, when the print head 3 has multiple nozzle rows or there is a manufacturing deviation in the nozzle row position, the translation mechanism can make fine adjustments in the nozzle row direction, thereby ensuring that the infrared laser 5 is always within the effective detection area of ​​the target nozzle row 4.

[0041] Under the control of the blockage detection unit, the path of the infrared laser 5 is confined within a spatial plane determined by the extension direction of the target nozzle row 4 and the direction perpendicular to the spraying side of the nozzle row, and remains parallel to the extension direction of the nozzle row, thereby constructing a stable spatial geometric relationship and forming a fixed mapping relationship between the nozzle spraying path and the optical detection path, avoiding detection errors caused by angular deviation or spatial offset.

[0042] In the actual detection process, the blockage detection unit sends a command to the print head 3 to drive the nozzles of the target nozzle row 4 to spray sequentially according to the first preset spray time interval. The nozzles trigger the spray action sequentially. Since the nozzle spraying is strictly ordered in time, combined with the fixed spot detection plane, the spraying behavior of each nozzle can be analyzed one-to-one with the spot signal within the corresponding time window. Thus, the status identification of the entire row of nozzles can be completed in one spraying process, and the location distribution and number of blocked nozzles can be finally obtained. Therefore, compared with the detection methods in the prior art that require point-by-point scanning or multiple alignments, this application can simultaneously detect the entire row of nozzles in one spraying process, without repeated scanning or complex image post-processing, and can quickly determine the location and number of blockages. This not only significantly improves the detection efficiency, but also reduces the probability of misjudgment caused by timing deviations and spatial alignment errors, while improving the overall accuracy and stability of nozzle blockage detection.

[0043] Preferably, in some embodiments of this application, determining the position and number of plugs in the target nozzle row 4 based on the light spot signal formed on the detection plane includes:

[0044] The first light spot signal is acquired, and based on the first light spot signal, the position and number of plugs of the target nozzle row 4 are determined; the first light spot signal is acquired at a second preset time interval after the injection command is issued.

[0045] The second preset time interval includes the time from when the printhead 3 receives the ejection command until all the ink droplets 6 formed by the sequential ejection of each nozzle in the target nozzle row 4 enter the detection area corresponding to the path of the infrared laser 5.

[0046] In detail, during the actual detection process, when the printhead 3 receives the ejection command, the nozzles do not eject simultaneously, but rather sequentially according to a predetermined time sequence. For example, nozzle number 1 starts ejecting at time T0, nozzle number 2 ejects at time T0+t2, and so on (where t2 is the first preset ejection time interval). Since the ink droplets 6 require a certain flight time after being ejected from the nozzles to enter the detection area corresponding to the infrared laser 5 path, there is a certain time delay in the light spot response corresponding to different nozzles. Based on this characteristic, this application does not perform real-time point-by-point detection on each nozzle separately, but introduces a second preset time interval and uniformly collects the first light spot signal at the time corresponding to this time interval. For example, this second preset time interval is defined as the time from when the printhead 3 receives the ejection command until all the ink droplets 6 formed by the sequential ejection of each nozzle in the target nozzle row 4 enter the detection area corresponding to the infrared laser 5 path. After this time point, all the ink droplets 6 ejected by the entire row of nozzles have stably entered the detection area, thereby achieving a fully stable light spot signal on the detection plane.

[0047] For example, when nozzle number 3 is clogged, if the first spot signal is acquired at the time corresponding to the second preset time interval, it can be observed on the detection plane that the ink droplets corresponding to nozzles number 1, 2, and 4 to N all produce normal spot responses, while nozzle number 3 lacks corresponding ink droplet spot characteristic signals within the corresponding time window. By analyzing this global spot distribution, the location of the clogged nozzle (nozzle number 3) and the number of clogged nozzles (at least one clogged nozzle) can be determined at once.

[0048] In another embodiment, when there are many nozzles, due to slight differences in the flight time of ink droplets from different nozzles, if the light spot signal is collected too early, some ink droplets from some nozzles may not have entered the detection area, leading to misjudgment. By introducing a second preset time interval, the collection time is delayed until all ink droplets formed by the spray from all nozzles have entered the detection area corresponding to the infrared laser path, thereby ensuring that the first light spot signal can fully reflect the true spraying state of the entire row of nozzles.

[0049] This application introduces a second preset time interval after the injection command is executed, and uniformly acquires the first spot signal at this time node. This transforms the detection process from sequential detection of each nozzle to full synchronous acquisition of the entire row of nozzles, thus avoiding the timing alignment error problem caused by real-time judgment of each nozzle. Simultaneously, since the second preset time interval covers the complete time process of all nozzle droplets entering the detection area corresponding to the infrared laser path in the target nozzle row, the acquired first spot signal has completeness and consistency, accurately reflecting the injection result of the entire row of nozzles and avoiding missed or false detections caused by differences in droplet flight delay. Therefore, this application, while ensuring the accuracy of the detection results, achieves rapid overall identification of the location and number of plugs in the target nozzle row. Compared with existing point-by-point scanning or multiple sampling methods, it significantly improves detection efficiency and enhances the stability and robustness of the detection results.

[0050] Preferably, in some embodiments of this application, the infrared laser generating unit 1 generates an infrared laser with a wavelength range of 750nm to 3000nm, for example, a near-infrared laser of 1064nm can be selected as the working wavelength. This wavelength range setting makes the infrared laser more stable and less susceptible to visible light interference when passing through air and ink droplet media, thereby improving the sensitivity of the spot detection unit 2 to the recognition of changes in the scattering of ink droplets 6.

[0051] The infrared laser has a circular or rectangular cross-section. For example, in one embodiment, a rectangular beam shaping structure is used to form a rectangular light band of a certain width on the detection plane; in another embodiment, a circular beam output is used, and an approximately circular spot area is formed by a beam expander. The purpose of this cross-section design is to enable the infrared laser to form a continuous coverage area on the detection plane, rather than a discrete dot-like spot, thereby enhancing the ability to simultaneously cover ink droplets from multiple nozzles.

[0052] The infrared laser 5 forms a spot on the detection plane with a coverage area greater than the overall distribution range of ink droplets 6 ejected by each nozzle in the target nozzle row on the detection plane, so that the image of the spot can simultaneously include the image of ink droplets ejected by each nozzle in the target nozzle row 4.

[0053] Specifically, in practical applications, taking a target nozzle row 4 with 15 nozzles as an example, the ink droplets 6 ejected by each nozzle will form imaging trajectories distributed at different spatial positions on the detection plane during flight. Their overall distribution range typically corresponds to the projection range of the nozzle row in space. To ensure that all ink droplets 6 ejected by all nozzles can be effectively captured within the same detection window, this application sets the coverage area of ​​the infrared laser 5's spot on the detection plane to be larger than the overall distribution range of the ink droplets 6. For example, when the 15 nozzles form laterally distributed ink droplet trajectories on the detection plane during ejection, if the infrared laser only covers a local area, ink droplets ejected by edge nozzles (such as nozzle number 1 or 15) may not enter the optical path range, resulting in detection loss. However, by expanding the coverage area of ​​the infrared laser spot to form a continuous light band covering the entire projection area of ​​the nozzle row on the detection plane, all ink droplets ejected by the nozzles can undergo scattering or occlusion changes within the same optical detection area, thus being simultaneously captured in the image of the same spot. For example, when the infrared laser coverage completely covers the entire distribution range of the nozzle row, the ink droplets formed by the ejection of nozzles No. 5, No. 11 and No. 14 will correspond to optical change areas at different spatial positions in the same frame of the light spot image. This allows the light spot image to simultaneously contain the ejection information of all nozzles in the target nozzle row 4, achieving synchronous imaging of the entire row and avoiding detection omissions caused by local occlusion or insufficient coverage.

[0054] In this embodiment of the application, the location and number of plugs in the target nozzle row 4 are determined based on the first light spot signal, specifically including:

[0055] Extract the edge information of each ink droplet image from the first spot signal to determine the center position of each ink droplet image;

[0056] Based on the center position of each ink droplet image in the first light spot signal, the position and number of plugs in the target nozzle row are determined.

[0057] Optionally, in some embodiments of this application, the location and number of plugs in the target nozzle row 4 are determined based on the center position of each ink droplet image in the first light spot signal, including:

[0058] Obtain the actual spacing sequence between the imaging center positions of adjacent ink droplets from bottom to top in the first spot signal;

[0059] Compare each actual spacing with the preset normal spacing sequentially from bottom to top;

[0060] If any actual spacing is greater than the preset normal spacing, it is determined that there are missing ink droplets in the ink droplet sequence interval corresponding to the actual spacing;

[0061] Based on the ratio of the actual spacing to the preset normal spacing, the number of missing ink droplets in the ink droplet sequence interval is determined, and position completion processing is performed in the ink droplet sequence interval to obtain the completed ink droplet sequence.

[0062] Based on the sequence number of the completed ink droplet in the completed ink droplet sequence and the arrangement order of the nozzles in the target nozzle row, the corresponding target nozzle is determined, and the target nozzle is determined to be clogged, so as to obtain the clog position and number of clogs in the target nozzle row.

[0063] For example, taking a target nozzle row 4 with 32 nozzles as an example, the infrared laser 5 forms a stable spot area covering the entire row of nozzles on the detection plane. The spot detection unit 2 images and acquires this area to obtain a first spot signal. This first spot signal contains the imaging results of ink droplets 6 formed by each nozzle on the detection plane. Since the ink droplets 6 will scatter, be blocked, or have brightness changes under the action of the infrared laser, each normally ejecting nozzle corresponds to an ink droplet image with obvious edge features. In this embodiment, the first spot signal is first processed to extract the edge information of each ink droplet image. For example, the outline of each ink droplet is obtained through an edge detection algorithm, and then the outline is geometrically fitted to determine the center position of each ink droplet image. Since the nozzle arrangement has a fixed spatial order, these center positions are approximately equally spaced on the detection plane. For example, under normal circumstances, the center positions of the ink droplets formed by the nozzles No. 1 to No. 32 are arranged from bottom to top on the detection plane, and the spacing between adjacent center positions is basically stable and consistent. This spacing can be defined as a preset normal spacing d. This normal spacing reflects the stable imaging pattern under the combined effects of the fixed physical distance between nozzles, the jetting time interval, and the droplet flight speed.

[0064] In actual testing, if nozzle number 12 becomes clogged, the actual distance between the center positions of the ink droplets corresponding to nozzle number 11 and nozzle number 13 in the first light spot signal will significantly increase. For example, a region with an initial adjacent distance of 'd' may now have a distance of approximately 2d or even larger, resulting in an abnormal abrupt change in distance. Based on this, this embodiment calculates the sequence of actual distances between the center positions of each adjacent ink droplet sequentially from bottom to top and compares them one by one with the preset normal distance 'd'. When an actual distance is detected to be significantly greater than 'd', it can be determined that there are missing ink droplets in the corresponding ink droplet sequence interval. For example, when an abnormal distance occurs between nozzles number 11 and 13, it can be inferred that the ink droplet image corresponding to nozzle number 12 is missing.

[0065] Furthermore, this embodiment does not simply mark the missing locations, but rather estimates the number of missing droplets based on the ratio between the actual spacing and the preset normal spacing. For example, when the actual spacing is approximately 2d, it can be inferred that one ink droplet is missing; when the actual spacing is approximately 3d, it can be inferred that two ink droplets are missing, and so on, thereby achieving a quantitative estimate of the number of missing ink droplets.

[0066] After determining the number of missing droplets, this embodiment performs "position completion processing" on the droplet sequence interval. This involves inserting a corresponding number of virtual sequence numbers between droplets 11 and 13, restoring the completed droplet sequence to a complete sequence structure consistent with the actual nozzle arrangement. Subsequently, a one-to-one mapping is performed between the completed sequence numbers and the physical arrangement of the nozzles in the target nozzle row to determine the specific nozzle number that is clogged. For example, in the above case, the completed sequence directly locates nozzle 12 as the missing position, thus determining that nozzle 12 is clogged and counting the number of clogged nozzles as 1.

[0067] This application first extracts the edge information of the ink droplet imaging based on the first spot signal and determines the center position. By introducing the actual spacing sequence between adjacent center positions and comparing it with the preset normal spacing, it can utilize the inherent spatial equidistant characteristics of the nozzle to quickly identify abnormal spacing changes, thereby effectively locating the interval where the missing ink droplet is located. Simultaneously, by calculating the number of missing ink droplets based on the spacing ratio and performing position completion processing, the incomplete sequence caused by clogging is restored to a structurally complete nozzle sequence, thus achieving a precise mapping between the missing position and the actual nozzle number. Therefore, this application can not only accurately determine the location of the clogging nozzle but also achieve quantitative identification of the number of clogging nozzles. Compared with traditional methods based solely on threshold judgment or overall image comparison, it has stronger structural interpretation capabilities and positioning accuracy, while significantly reducing the probability of false detection and false negative detection, and improving the reliability of nozzle clogging detection.

[0068] In another specific embodiment of this application, taking a target nozzle row of 4 as an example with 6 nozzles, the nozzles are numbered sequentially from nozzle 1 to nozzle 6. The infrared laser generation unit forms a stable light spot coverage area within the detection plane, and the light spot detection unit images and acquires this area to obtain a first light spot signal. Based on this first light spot signal, the ink droplet images formed by each nozzle can be extracted, and the edge information of each ink droplet image can be further extracted to determine the center position of each ink droplet image. See also... Figure 2 Under normal circumstances, when all six nozzles are ejecting ink normally, six sequentially arranged ink droplet centers will be formed on the detection plane. Their spatial distribution, from bottom to top along the nozzle arrangement, is P1, P2, P3, P4, P5, and P6, and the actual distance between adjacent center positions is basically the same. This distance can be defined as the preset normal distance d. (See also...) Figure 3 In this embodiment, assuming the third nozzle is clogged, meaning it fails to form effective ink droplets or the droplets do not enter the infrared laser detection area, only five effective ink droplet center positions can be extracted from the first spot signal, namely P1, P2, P4, P5, and P6. In this case, the ink droplet imaging corresponding to the third nozzle is missing, resulting in a break in the spatial distribution continuity.

[0069] Furthermore, the extracted ink droplet center positions are sorted from bottom to top, and the actual spacing sequence between adjacent center positions is calculated. Specifically, the spacing between P2 and P1 is approximately d, which is a normal spacing; while the spacing between P4 and P2 is approximately 2d, significantly larger than the preset normal spacing d, indicating an abnormal spacing interval between P2 and P4; subsequently, the spacing between P5 and P4 returns to d, and the spacing between P6 and P5 is also d. Therefore, it can be determined that there is a missing ink droplet imaging point within the interval between P2 and P4. In this embodiment, based on the ratio between the actual spacing and the preset normal spacing d, the number of missing ink droplets can be further determined. When the actual spacing is approximately 2d, it indicates that one ink droplet imaging point is missing in this interval. Therefore, it can be determined that one ink droplet is missing between P2 and P4, corresponding to the missing ejection result of the third nozzle in the nozzle sequence.

[0070] After determining the number of missing droplets, this embodiment performs completion processing on the droplet sequence by inserting a virtual position P3 between P2 and P4, restoring the complete droplet sequence to the full structure of P1, P2, P3, P4, P5, and P6. Subsequently, this completed sequence is mapped to the physical nozzle arrangement order of the target nozzle row 4, thereby determining that P3 corresponds to the position of the third nozzle. This leads to the determination that the third nozzle is clogged, and the clogged nozzle is identified as the third nozzle, with a clog count of 1.

[0071] As can be seen from the above method, this application obtains the center position of the ink droplet through the first spot signal, and uses the relationship between the actual distance between adjacent center positions and the preset normal distance to identify and estimate the number of missing ink droplets. Combined with sequence completion and nozzle mapping processes, it achieves precise location of the clogged nozzle. In the specific scenario of a third nozzle clogging, this method can clearly and accurately determine the clogging location through the logical chain of spacing anomaly—missing droplet determination—sequence completion—number mapping, avoiding the positioning ambiguity or misjudgment problems caused by relying on overall image comparison in traditional methods, thereby improving the accuracy and reliability of nozzle clogging detection.

[0072] Optionally, in some other embodiments of this application, the location and number of clogging points in the target nozzle row 4 are determined based on the center position of each ink droplet in the first light spot signal, including:

[0073] In the coordinate system of the light spot image corresponding to the detection plane, obtain the center position of each ink droplet image in the image of the light spot corresponding to the first light spot signal;

[0074] Using the nozzle ejection direction as the positive longitudinal direction of the light spot image coordinate system, the imaging center positions of each ink droplet are sorted in ascending order of their longitudinal coordinate values ​​to obtain an ordered sequence of ink droplet positions.

[0075] The imaging center position of each ink droplet in the ink droplet position sequence is matched with the theoretical jet longitudinal position interval corresponding to each nozzle in a pre-determined manner to determine the nozzle number that has already been ejected.

[0076] Wherein, the theoretical jet longitudinal position range is the expected distribution range of ink droplets corresponding to each nozzle in the coordinate system of the light spot image;

[0077] The clogged nozzles are identified based on the nozzle numbers corresponding to the theoretical jet longitudinal position intervals where the ink droplet imaging center position is not matched.

[0078] The blocked nozzles are statistically analyzed to obtain the location and number of plugs in the target nozzle row 4.

[0079] In detail, taking a target nozzle row of 4 with 6 nozzles as an example, a two-dimensional image coordinate system is established in the image of the light spot corresponding to the detection plane. The vertical direction is consistent with the nozzle spray direction and is defined as the positive vertical direction, while the horizontal direction corresponds to the nozzle arrangement direction. The infrared laser generation unit 1 forms a stable light spot coverage area, and the light spot detection unit 2 acquires the first light spot signal and generates an image of the light spot. In the image of the light spot, each ink droplet formed by the normal nozzle spray corresponds to an imaging area with clear edge features, and its center position coordinates can be extracted by image processing methods.

[0080] In this embodiment, the first spot signal is first processed to extract the center position (x, y) of each ink droplet image in the spot image coordinate system. Then, using the nozzle ejection direction as the positive longitudinal direction, all ink droplet image center positions are sorted in ascending order of their longitudinal coordinate y-values, thus obtaining an ordered sequence of ink droplet positions. For example, when all six nozzles are ejecting normally, six center position points can be obtained, with their longitudinal distribution showing a bottom-up sequential arrangement. Furthermore, to predict the correspondence between the nozzles and the image space, this embodiment pre-establishes the theoretical ejection longitudinal position interval for each nozzle. This theoretical ejection longitudinal position interval is the expected distribution range of ink droplets in the spot image coordinate system, pre-calculated based on nozzle structural parameters, ejection time intervals, and ink droplet flight speed. For example, the first nozzle corresponds to interval A1, the second nozzle to interval A2, and so on up to the sixth nozzle to interval A6, with each interval being sequentially or approximately continuously distributed longitudinally.

[0081] In actual testing, by sequentially matching the sorted droplet center positions with each theoretical jetting longitudinal position interval, it can be determined which nozzles successfully completed jetting. For example, if at least one droplet center position falls within a certain theoretical interval, the nozzle is considered to have jetted normally; if no droplet center position is matched within a certain theoretical interval, the nozzle is considered to be clogged or not dispensing ink. For instance, in the case of a clogged nozzle 3, only the droplet center positions corresponding to nozzles 1, 2, 4, 5, and 6 can be extracted from the image of the light spot. Among them, the droplet center point is present in interval A1 corresponding to nozzle 1, in interval A2 corresponding to nozzle 2, but there is no droplet center position in interval A3 corresponding to nozzle 3, while droplet center points are present in intervals A4 to A6 corresponding to nozzles 4 to 6. Therefore, it can be directly determined that nozzle 3 did not match any droplet imaging center position, thus indicating that nozzle 3 is clogged.

[0082] Finally, by statistically analyzing the nozzle numbers corresponding to all theoretical jet longitudinal position intervals that did not match the ink droplet imaging center position, the set of clogged nozzles can be obtained. For example, in this embodiment, only the interval A3 corresponding to the 3rd nozzle was not successfully matched, therefore the clogged position is the 3rd nozzle, and the number of clogged nozzles is 1.

[0083] In the above manner, this application first extracts the center position of the ink droplet in the coordinate system of the light spot image, and sorts them with the nozzle spray direction as the longitudinal positive direction, so that the original optical signal is structured into an ordered data sequence with spatial order relationship, thereby providing a basis for subsequent matching analysis.

[0084] Furthermore, by introducing the theoretical jetting longitudinal position intervals corresponding to each nozzle, the physical structural parameters of the nozzles are pre-bound to the spatial distribution intervals of the image. This transforms the detection process from post-event image analysis to matching judgment based on prior intervals, significantly improving the stability and interpretability of nozzle recognition. Simultaneously, by identifying the theoretical jetting longitudinal position intervals that do not match the center position of the ink droplet, direct location of clogged nozzles is achieved, avoiding the error accumulation problems caused by reliance on spacing calculations or complex image reconstruction in traditional methods. This makes the clog judgment logic more direct and clear. Therefore, this application can quickly complete nozzle jetting state recognition during a single spot image acquisition process and accurately output the clog position and number of clogs, offering advantages such as accurate positioning, strong robustness, and simple engineering implementation.

[0085] Preferably, in some embodiments of this application, determining the position and number of plugs in the target nozzle row based on the light spot signal formed on the detection plane includes:

[0086] When the injection command is received at the target nozzle row, a timer is started synchronously;

[0087] Based on the nozzle spraying sequence and the first preset spraying time interval, a correspondence between the nozzle number and the detection time interval is established. For the nth nozzle, its corresponding detection time interval is determined as: [t1+(n-1)t2-0.5t2, t1+(n-1)t2+0.5t2]; where t1 is the pre-acquired delay time and t2 is the first preset spraying time interval.

[0088] During nozzle ejection, if the spot detection unit detects an ink droplet spot signal at the center of the spot signal within the detection time interval corresponding to the nth nozzle, the nth nozzle is determined to be a normal nozzle and its clogging mark is set to normal.

[0089] If the spot detection unit does not detect an ink droplet spot signal at the center of the spot signal within the corresponding detection time interval, the nth nozzle is determined to be a clogged nozzle and its clog mark is set to clogged.

[0090] After determining the number of nozzles in the target nozzle row, count the number of nozzles marked as blocked to determine the number of plugs, and determine the location of the plugs based on the number of the nozzles marked as blocked in the nozzle sequence.

[0091] For example, taking a target nozzle row 4 with 6 nozzles as an example, the nozzles are numbered sequentially from nozzle 1 to nozzle 6. The infrared laser generation unit 1 generates a parallel infrared laser along the extension line of the nozzle row, and the spot detection unit 2 is used to collect the spot signal in a detection plane that is consistent with the normal direction of the nozzle row. When the print head 3 receives the ejection command, the blockage detection unit synchronously starts the timer, and uses this moment as the time base t0. At the same time, combined with the pre-acquired delay time t1 and the first preset ejection time interval t2, a one-to-one correspondence between the nozzle number and the detection time interval is established.

[0092] Specifically, for the nth nozzle, its corresponding detection time interval is defined as: [t1+(n-1)t2-0.5t2, t1+(n-1)t2+0.5t2]. For example, the time interval for the first nozzle is [t1-0.5t2, t1+0.5t2], the time interval for the second nozzle is [t1+0.5t2, t1+1.5t2], and so on, with the time interval for the sixth nozzle being [t1+4.5t2, t1+5.5t2]. This time interval is set to cover the main time fluctuation range from ink droplet ejection to entry into the infrared laser detection area, thereby ensuring the consistency between the detection timing and the actual ejection process. In the actual detection process, the example of the third nozzle becoming clogged will be used for illustration. After the injection command is executed, the first nozzle ejects ink droplets 6 within its corresponding time interval. When these droplets 6 enter the infrared laser path, the spot detection unit 2 detects a significant change in the center of the ink droplet spot signal within the time interval corresponding to the first nozzle. Therefore, the first nozzle is determined to be a normal nozzle and marked as normal. Similarly, the second nozzle also detects the center of the ink droplet spot signal within its corresponding time interval and is thus also determined to be normal.

[0093] When entering the detection time interval corresponding to the third nozzle, if the third nozzle is clogged and fails to eject ink droplets 6, or if the ejected ink droplets do not enter the detection area, the spot detection unit does not detect any change in the center of the spot signal with ink droplet characteristics within this time interval. Therefore, the third nozzle is determined to be a clogged nozzle, and its blockage mark is set to clogged. Subsequently, the fourth, fifth, and sixth nozzles complete ejection and generate valid ink droplet spot signals in their respective detection time intervals, and are therefore all marked as normal nozzles. This completes the individual determination of each of the six nozzles. After all nozzles have been detected, the blockage marking results are statistically analyzed. It is found that only the third nozzle is marked as clogged, therefore the number of blockages is 1. Furthermore, the location of the blockage can be determined as the third nozzle based on its number in the nozzle sequence.

[0094] In this embodiment, the method for obtaining the delay time t1 includes:

[0095] Select any nozzle in row 4 of the target nozzles as the calibration nozzle;

[0096] Send a jet trigger signal to the calibration nozzle, and use the time of sending the jet trigger signal as the time starting point;

[0097] The moment when the spot detection unit detects the appearance of the ink droplet spot signal corresponding to the calibration nozzle at the center of the spot signal is recorded as the detection moment, and the time difference between the detection moment and the time start point is calculated, and the time difference is used as a delay measurement value.

[0098] Repeat the above measurement process multiple times to obtain multiple delayed measurement values;

[0099] The multiple delay measurements are statistically processed to obtain an average or weighted average, which is used as the delay time t1.

[0100] In one specific embodiment, taking six nozzles as an example, to improve the timing matching accuracy between the ejection time and the spot detection, this embodiment calibrates and obtains the delay time t1. Specifically, any one of the six nozzles is selected as the calibration nozzle, for example, the second nozzle is selected as the calibration target. During the calibration process, the control system sends a single ejection trigger signal to the second nozzle, and the sending time of this trigger signal is defined as the time start point t0. After the ejection trigger, the second nozzle completes the ink droplet ejection. The ink droplet flies in space and enters the detection optical path area formed by the infrared laser generation unit. When the ink droplet passes through the infrared laser path, it will generate a significant change in the center of the spot signal on the detection plane corresponding to the spot detection unit. The time t1' when the center of the spot signal first appears corresponding to the ink droplet ejected by the second nozzle is recorded, and the time difference Δt1 = t1' - t0 between this time and the time start point t0 is calculated. This time difference is used as a delay measurement value. This time difference reflects the comprehensive delay between the nozzle triggering ejection and the ink droplet actually entering the optical detection area, including factors such as ejection response delay, ink droplet flight time, and optical detection response time. To improve the stability and representativeness of the delay time t1, this embodiment repeats the above measurement process multiple times, for example, performing 20 or 50 independent injection and detection operations consecutively, recording the corresponding delay measurement value each time. Since a single measurement may be affected by airflow disturbances, minor injection fluctuations, or detection noise, there may be some dispersion among the multiple measurement values. Subsequently, statistical processing is performed on the multiple delay measurement values, for example, using an arithmetic mean or a weighted average after removing extreme values, to obtain a stable delay time t1. For example, averaging the remaining data after removing the maximum and minimum values ​​can further reduce the impact of abnormal measurements on the results, making the obtained t1 more reliable.

[0101] The printhead nozzle clogging rapid detection device provided in this application embodiment generates parallel infrared lasers by setting an infrared laser generation unit on the extension line of the nozzle row, and uses a spot detection unit to collect the spot signals formed in the detection plane in real time, so that the ink droplet spots generated during the nozzle ejection process can be stably imaged in a unified detection plane. At the same time, the infrared laser generation unit and the spot detection unit are driven to translate synchronously along the nozzle row arrangement direction by a translation mechanism, so that the infrared laser path is spatially adapted to the target nozzle row, and under the control of the clogging detection unit, the infrared laser path is stably located in the plane jointly determined by the extension direction of the nozzle row and its normal direction and maintains a parallel relationship, thereby establishing a stable spatial mapping relationship between the nozzle row and the optical detection plane. Furthermore, during the process of driving the nozzles of the target nozzle row to eject sequentially according to a first preset ejection time interval, the nozzle ejection sequence is analyzed in correspondence with the spot signals in the detection plane, so that the spot responses generated by different nozzles can be distinguished and matched under a unified time reference, thereby completing the analysis of the overall ejection state of the target nozzle row in a single ejection process, and thus simultaneously determining the clogging position and number of clogging. Therefore, compared with the point-by-point scanning or local detection methods in the prior art, the embodiments of this application can quickly and synchronously detect the entire row of nozzles in one spraying process, without the need for multiple alignments or repeated scanning, so as to quickly determine the location and number of blockages, thereby significantly improving detection efficiency and positioning accuracy, and enhancing the integrity and reliability of detection results.

[0102] On the other hand, see Figure 4 This embodiment also provides a printing device, including: a printhead and a rapid nozzle clogging detection device for the printhead described in the above embodiment.

[0103] In actual operation, this printing device integrates the infrared laser generation unit, spot detection unit, and blockage detection unit with the print head, enabling the nozzle ejection process and optical detection process to be completed synchronously within the same system. This allows for rapid online detection of the target nozzle row. Specifically, during printing, while driving the target nozzle row to perform one ejection action, a rapid nozzle blockage detection process is simultaneously initiated. Infrared lasers provide uniform optical coverage of the ink droplets ejected from the nozzle row, and the spot detection unit acquires the spot signals corresponding to the entire row of nozzles within the same detection window. Because each nozzle completes its ejection action sequentially within the same ejection cycle and enters the detection area under a unified detection time reference, complete imaging information of the entire row of nozzles can be acquired synchronously during a single ejection. Based on this, the blockage detection unit can determine the status of all nozzles in the target nozzle row at once, directly identifying the location and number of blockages, based on the spot signals within the same frame or time window. For example, for a nozzle row containing 6 or 32 nozzles, only one ejection and one spot acquisition process are needed to complete the full detection of the entire row of nozzles, eliminating the need for repeated scanning or multiple alignment operations for each nozzle.

[0104] In the description of this application, it should be understood that 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 number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0105] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; 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 of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0106] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first and second features are in direct contact, or that they are in indirect contact through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0107] In the description of this specification, the terms "one embodiment," "some embodiments," "embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0108] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make modifications, alterations, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A rapid detection device for nozzle clogging in a printhead, characterized in that, include: An infrared laser generating unit is used to generate a parallel infrared laser beam along the extension line of the nozzle row of the printhead. A spot detection unit is used to detect the spot signal formed by the infrared laser on a detection plane that is aligned with the normal direction of the target nozzle. A translation mechanism is used to drive the infrared laser generating unit and the spot detection unit to translate synchronously along the nozzle row arrangement direction so that the path of the infrared laser is adapted to the target nozzle row. The blockage detection unit controls the translation mechanism to ensure that the path of the infrared laser is located in a plane jointly determined by the extension direction of the target nozzle row and the direction perpendicular to the target nozzle row on the spray side, and the path of the infrared laser is parallel to the extension direction of the target nozzle row. When a spray command is issued to the print head to drive the nozzles of the target nozzle row to spray sequentially according to a first preset spray time interval, the unit determines the position and number of blockages in the target nozzle row based on the light spot signal formed on the detection plane.

2. The rapid detection device for nozzle clogging of the printhead according to claim 1, characterized in that, Based on the light spot signal formed on the detection plane, determine the location and number of plugs in the target nozzle row, including: The first light spot signal is acquired, and based on the first light spot signal, the position and number of plugs in the target nozzle row are determined; the first light spot signal is acquired at a second preset time interval after the injection command is issued.

3. The rapid detection device for nozzle clogging of the printhead according to claim 2, characterized in that, The infrared laser generating unit generates an infrared laser with a wavelength range of 750nm to 3000nm. The cross-section of the infrared laser is circular or rectangular. The coverage area of ​​the light spot formed by the infrared laser on the detection plane is greater than the overall distribution range of the ink droplets ejected by each nozzle in the target nozzle row on the detection plane, so that the image of the light spot can simultaneously include the imaging of the ink droplets ejected by each nozzle in the target nozzle row.

4. The rapid detection device for nozzle clogging of the printhead according to claim 3, characterized in that, The second preset time interval includes the time from when the printhead receives the ejection command until all ink droplets formed by the sequential ejection of each nozzle in the target nozzle row enter the detection area corresponding to the infrared laser path.

5. The rapid detection device for nozzle clogging of the printhead according to claim 4, characterized in that, Based on the first light spot signal, the location and number of plugs in the target nozzle row are determined, specifically including: Extract the edge information of each ink droplet image from the first spot signal to determine the center position of each ink droplet image; Based on the center position of each ink droplet image in the first light spot signal, the position and number of plugs in the target nozzle row are determined.

6. The rapid detection device for nozzle clogging of the printhead according to claim 5, characterized in that, Based on the center position of each ink droplet image in the first light spot signal, the location and number of clogging nozzles in the target nozzle row are determined, including: Obtain the actual spacing sequence between the imaging center positions of adjacent ink droplets from bottom to top in the first spot signal; Compare each actual spacing with the preset normal spacing sequentially from bottom to top; If any actual spacing is greater than the preset normal spacing, it is determined that there are missing ink droplets in the ink droplet sequence interval corresponding to the actual spacing; Based on the ratio of the actual spacing to the preset normal spacing, the number of missing ink droplets in the ink droplet sequence interval is determined, and position completion processing is performed in the ink droplet sequence interval to obtain the completed ink droplet sequence. Based on the sequence number of the completed ink droplet in the completed ink droplet sequence and the arrangement order of the nozzles in the target nozzle row, the corresponding target nozzle is determined, and the target nozzle is determined to be clogged, so as to obtain the clog position and number of clogs in the target nozzle row.

7. The rapid detection device for nozzle clogging of the printhead according to claim 5, characterized in that, Based on the center position of each ink droplet in the first light spot signal, the location and number of clogging nozzles in the target nozzle row are determined, including: In the coordinate system of the light spot image corresponding to the detection plane, obtain the center position of each ink droplet image in the image of the light spot corresponding to the first light spot signal; Using the nozzle ejection direction as the positive longitudinal direction of the light spot image coordinate system, the imaging center positions of each ink droplet are sorted in ascending order of their longitudinal coordinate values ​​to obtain an ordered sequence of ink droplet positions. The imaging center position of each ink droplet in the ink droplet position sequence is matched with the theoretical jet longitudinal position interval corresponding to each nozzle in the pre-determined sequence to determine the nozzle number that has been jetted. Wherein, the theoretical jet longitudinal position range is the expected distribution range of ink droplets corresponding to each nozzle in the coordinate system of the light spot image; The clogged nozzles are identified based on the nozzle numbers corresponding to the theoretical jet longitudinal position ranges where the ink droplet imaging center position is not matched. The blocked nozzles are statistically analyzed to obtain the location and number of blockages in the target nozzle row.

8. The rapid detection device for nozzle clogging of the printhead according to claim 1, characterized in that, Based on the light spot signal formed on the detection plane, determine the location and number of plugs in the target nozzle row, including: When the injection command is received at the target nozzle row, a timer is started synchronously; Based on the nozzle spraying sequence and the first preset spraying time interval, a correspondence between the nozzle number and the detection time interval is established. For the nth nozzle, its corresponding detection time interval is determined as: [t1+(n-1)t2-0.5t2, t1+(n-1)t2+0.5t2]; where t1 is the pre-acquired delay time and t2 is the first preset spraying time interval. During nozzle ejection, if the spot detection unit detects an ink droplet spot signal at the center of the spot signal within the detection time interval corresponding to the nth nozzle, the nth nozzle is determined to be a normal nozzle and its clogging mark is set to normal. If the spot detection unit does not detect an ink droplet spot signal at the center of the spot signal within the corresponding detection time interval, the nth nozzle is determined to be a clogged nozzle and its clog mark is set to clogged. After determining the number of nozzles in the target nozzle row, count the number of nozzles marked as blocked to determine the number of plugs, and determine the location of the plugs based on the number of the nozzles marked as blocked in the nozzle sequence.

9. The rapid detection device for nozzle clogging of the printhead according to claim 8, characterized in that, The methods for obtaining the delay time t1 include: Select any nozzle from the target nozzle row as the calibration nozzle; Send a jet trigger signal to the calibration nozzle, and use the time of sending the jet trigger signal as the time starting point; The moment when the spot detection unit detects the appearance of the ink droplet spot signal corresponding to the calibration nozzle at the center of the spot signal is recorded as the detection moment, and the time difference between the detection moment and the time start point is calculated, and the time difference is used as a delay measurement value. Repeat the above measurement process multiple times to obtain multiple delayed measurement values; The multiple delay measurements are statistically processed to obtain an average or weighted average, which is used as the delay time t1.

10. A printing device, characterized in that, include: Print head; The rapid detection device for nozzle clogging of the printhead according to any one of claims 1-9.

Images