Clogging detection device for a printer head based on multiple light paths and printing apparatus

Abstract

The application relates to the technical field of printing equipment, in particular to a clogging detection device of a printer nozzle based on multiple light paths and printing equipment. The device comprises a first infrared laser generating unit, a first light spot detection unit, a second infrared laser generating unit for generating a second infrared laser, a second light spot detection unit for detecting a light spot signal formed by the second infrared laser on a second detection plane, a translation mechanism for driving the first infrared laser generating unit and the first light spot detection unit to synchronously translate and driving the second infrared laser generating unit and the second light spot detection unit to synchronously translate, and a clogging detection unit for enabling the intersection of the first infrared laser and the second infrared laser to be located on an extended line of a central axis of a target nozzle through the translation mechanism and acquiring the first light spot signal and the second light spot signal to determine the working state of the target nozzle.

Description

Technical Field

[0001] This application relates to the field of printing equipment technology, and in particular to a clogging detection device for a multi-optical-path printer nozzle and a printing device. Background Technology

[0002] In inkjet printers, the printhead, as the core component for image output, directly determines print quality through the operational status of its internal nozzle array. Over long-term use, nozzles are susceptible to clogging or jetting abnormalities due to factors such as ink drying, impurity buildup, or air bubbles, leading to issues like broken lines, color distortion, or blurriness in the printed image. Therefore, accurately and promptly detecting the nozzle's operational status is a crucial technical challenge for ensuring print quality and reliable equipment operation.

[0003] In existing technologies, methods for detecting the nozzle status of printer printheads mainly include visual inspection methods based on printed test patterns. These visual inspection methods typically involve printing a preset test pattern, followed by analysis of the print result by the user or an image processing algorithm to determine if the nozzle is clogged or misaligned. However, these methods rely on actual print results, resulting in long detection cycles, lack of real-time feedback, and susceptibility to factors such as paper quality, ambient lighting, and image processing accuracy, leading to poor detection stability. Summary of the Invention

[0004] (a) Technical problems to be solved

[0005] In view of the above-mentioned shortcomings and deficiencies of the prior art, this application provides a multi-optical-path printer nozzle clogging detection device and printing equipment, which solves the technical problems of long detection cycle, inability to provide real-time feedback and single detection dimension in the existing nozzle detection scheme.

[0006] (II) Technical Solution

[0007] To achieve the above objectives, the main technical solutions adopted in this application include:

[0008] In a first aspect, embodiments of this application provide a printer nozzle clogging detection device based on multiple optical paths, comprising: a first infrared laser generating unit for generating a first infrared laser, the first infrared laser being parallel to the extension line of the nozzle row of the printhead; a first spot detection unit for detecting a spot signal formed by the first infrared laser on a first detection plane, the first detection plane being aligned with the normal direction of the nozzle row; a second infrared laser generating unit for generating a second infrared laser, the second infrared laser being perpendicular to the first infrared laser in the horizontal direction; a second spot detection unit for detecting a spot signal formed by the second infrared laser on a second detection plane, the second detection plane being perpendicular to the second infrared laser; and a translation mechanism for driving the first infrared laser generating unit and the first spot detection unit to synchronously translate along the array direction of the nozzle row, so that the first infrared laser is adapted to the nozzle row. The target nozzle row, and the drive for the second infrared laser generating unit and the second spot detection unit to synchronously translate along the nozzle arrangement direction in the nozzle row; the blockage detection unit is used to control the movement of the first infrared laser generating unit, the second infrared laser generating unit, the first spot detection unit and the second spot detection unit through the translation mechanism, so that the intersection of the first infrared laser and the second infrared laser is located on the extension line of the central axis of the target nozzle in the target nozzle row, and when a spray command is issued to the target nozzle, acquire the first spot signal and the second spot signal, and determine the working state of the target nozzle based on the first spot signal and the second spot signal, wherein the first spot signal is detected by the first spot detection unit at a preset time interval after the spray command is issued; the second spot signal is detected by the second spot detection unit at a preset time interval after the spray command is issued.

[0009] Optionally, in some embodiments of this application, the preset time interval includes the ejection delay when the printhead receives the ejection command to the target nozzle and the flight time required for the ink droplet to move from the target nozzle to the intersection of the first infrared laser and the second infrared laser.

[0010] Optionally, in some embodiments of this application, the wavelength range of the first infrared laser and the second infrared laser is 750nm to 3000nm, the cross-section of the first infrared laser and the second infrared laser is circular or rectangular, the diameter of the spot image formed by the first infrared laser on the first detection plane is larger than the maximum diameter of the ink droplet ejected from the target nozzle, and the diameter of the spot image formed by the second infrared laser on the second detection plane is larger than the maximum diameter of the ink droplet ejected from the target nozzle.

[0011] Optionally, in some embodiments of this application, the blockage detection unit is further configured to: determine a first intensity difference between the first spot signal and a pre-acquired third spot signal, and a second intensity difference between the second spot signal and a pre-acquired fourth spot signal; determine that the target nozzle is in a normal spraying state when both the first intensity difference and the second intensity difference are greater than a preset threshold; determine that the target nozzle is in a blocked state when both the first intensity difference and the second intensity difference are less than or equal to the preset threshold; determine that the spraying angle of the target nozzle in the straight line direction where the target nozzle row is located is abnormal when the first intensity difference is greater than the preset threshold and the second intensity difference is less than or equal to the preset threshold; determine that the spraying angle of the target nozzle in the direction perpendicular to the straight line where the target nozzle row is located is abnormal when the second intensity difference is greater than the preset threshold and the first intensity difference is less than or equal to the preset threshold; the third spot signal is a spot signal formed by the first infrared laser on the first detection plane when no ink droplets pass through the first infrared laser; the fourth spot signal is a spot signal formed by the second infrared laser on the second detection plane when no ink droplets pass through the second infrared laser.

[0012] Optionally, in some embodiments of this application, the blockage detection unit is further configured to: acquire a corresponding first spot image based on the first spot signal, and acquire a corresponding second spot image based on the second spot signal, and determine whether dark spots appear in the first spot image and the second spot image respectively, wherein the dark spot is a local light intensity reduction area caused by the ink droplet passing through the infrared laser path in the spot image; if dark spots appear in both the first spot image and the second spot image, then the target nozzle is determined to be in a normal spraying state; if no dark spots appear in either the first spot image or the second spot image, then the target nozzle is determined to be in a blocked state; if dark spots appear in the first spot image and no dark spots appear in the second spot image, then the spraying angle of the target nozzle in the direction of the nozzle row is abnormal; if no dark spots appear in the first spot image and dark spots appear in the second spot image, then the spraying angle of the target nozzle in the direction perpendicular to the direction of the target nozzle row is abnormal.

[0013] Optionally, in some embodiments of this application, the blockage detection unit is further configured to, when determining that the target nozzle is in a normal spraying state, determine whether the target nozzle has a spraying direction deviation in the straight line direction of the nozzle row based on the position of the dark spot in the first spot image and a preset first effective detection area of ​​the first spot image. Specifically, the line connecting the projection point of the target nozzle position on the first detection plane and the center position of the first spot image formed by the first infrared laser on the first detection plane is used as the first reference axis. Two boundary rays with an angle not greater than a preset spray deviation angle extend from both sides of the first reference axis. The first effective detection area is the intersection of the area enclosed by the boundary rays and the projection area of ​​the first spot image on the first detection plane. Specifically, if the position of the dark spot in the first spot image is within the preset first effective detection area of ​​the first spot image, it is determined that the target nozzle has no spraying direction deviation in the straight line direction of the nozzle row; if the position of the dark spot in the first spot image is outside the preset first effective detection area of ​​the first spot image, it is determined that the target nozzle has a spraying direction deviation in the straight line direction of the nozzle row.

[0014] Optionally, in some embodiments of this application, the blockage detection unit is further configured to, when determining that the target nozzle is in a normal spraying state, determine whether there is a spraying direction deviation in the direction perpendicular to the straight line where the target nozzle and the nozzle row are located, based on the position of the dark spot in the second spot image and a preset second effective detection area of ​​the second spot image. The second reference axis is defined as the line connecting the projection point of the target nozzle position on the second detection plane and the center position of the second spot image formed by the second infrared laser on the second detection plane. Two boundary rays with an angle not greater than a preset spray deviation angle extend from both sides of the second reference axis. The second effective detection area is the intersection of the area enclosed by the boundary rays and the projection area of ​​the second spot image on the second detection plane. Specifically, if the position of the dark spot in the second spot image is within the preset second effective detection area of ​​the second spot image, it is determined that there is no spraying direction deviation in the direction perpendicular to the straight line where the target nozzle and the nozzle row are located; if the position of the dark spot in the second spot image is outside the preset second effective detection area of ​​the second spot image, it is determined that there is a spraying direction deviation in the direction perpendicular to the straight line where the target nozzle and the nozzle row are located.

[0015] Optionally, in some embodiments of this application, the blockage detection unit is further configured to, when determining that the target nozzle is in a normal spraying state, extract image features from the first spot image and the second spot image respectively to obtain first spot image features and second spot image features; input the first spot image features and the second spot image features into a pre-trained image recognition model respectively to obtain a first spray angle and a second spray angle; wherein, the first spray angle is the spray angle of the target nozzle in the direction of the straight line where the nozzle row is located, and the second spray angle is the spray angle of the target nozzle in the direction perpendicular to the straight line where the nozzle row is located; compare the first spray angle and the second spray angle with a preset angle tolerance range respectively, and if the first spray angle is greater than the preset angle tolerance range, the first spray angle is determined to be greater than the preset angle tolerance range. Within the angular tolerance range, it is determined that the target nozzle has a spray direction offset in the straight line direction where the nozzle row is located; when the second spray angle is greater than the preset angular tolerance range, it is determined that the target nozzle has a spray direction offset in the direction perpendicular to the straight line where the nozzle row is located; wherein, the first spot image feature and the second spot image feature both include the center position coordinates, area parameters, and local grayscale decrease amplitude of the dark spot, and the local grayscale decrease amplitude is the difference between the average pixel grayscale value of the dark spot in the corresponding spot image and the average pixel grayscale value of the spot area excluding the dark spot; the image recognition model is pre-trained based on training data, and the training data includes the first spot image feature and the second spot image feature collected under different known spray angle conditions and the corresponding spray angle annotation information.

[0016] Optionally, in some embodiments of this application, the clogging detection unit is further configured to, when determining that the target nozzle is in a normal spraying state, acquire the dark spot features of the first spot image or the second spot image, and determine whether the ink droplet corresponding to the dark spot is rotating based on the dark spot features; the dark spot features include: the roundness of the dark spot outline, the aspect ratio, the smoothness of the dark spot edge, and the skewness of the edge curve; wherein, the skewness of the edge curve of the dark spot is obtained by: fitting the edge curve based on the extracted dark spot edge curve coordinates, and calculating the angle between the edge curve and the reference axis from the nozzle position to the center of the corresponding first spot image or the second spot image, and using the angle as a quantitative value of the skewness of the edge curve.

[0017] Secondly, embodiments of this application provide a printing device, including: a printhead; and the above-described multi-optical-path-based printer printhead clogging detection device.

[0018] (III) Beneficial Effects

[0019] The printer nozzle clogging detection device based on multi-optical paths provided in this application controls a first infrared laser generating unit and a second infrared laser generating unit so that the intersection of the first and second infrared lasers is located on the extended line of the central axis of the target nozzle in the target nozzle row. When a spray command is issued to the target nozzle, a first spot signal and a second spot signal are acquired, thereby determining the working state of the target nozzle based on the first and second spot signals. Since the first and second infrared lasers form a mutually perpendicular multi-optical path cross detection structure in space, the spray response information of the target nozzle in different directions can be acquired simultaneously during the same spray triggering process. Therefore, multiple detections or multi-step analyses are unnecessary, and the presence of a clogging state in the target nozzle can be determined in one step. Furthermore, when ink is sprayed from the target nozzle, the changes in the first and second spot signals can be used to further determine whether the ink spray direction has shifted relative to the extended line of the central axis, thereby identifying whether the ink spray angle is abnormal. Therefore, this application can not only quickly determine the nozzle blockage status, but also simultaneously identify abnormal spray angles during a single detection process. Compared with existing technical solutions that require multiple detections or rely on single-direction signal analysis, it significantly improves detection efficiency and enhances the comprehensiveness and accuracy of detection results. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of a multi-optical-path printer nozzle clogging detection device according to an embodiment of this application;

[0021] Figure 2 This is a schematic diagram showing a dark spot in a first spot image according to an embodiment of this application;

[0022] Figure 3 This is a schematic diagram of a second spot image according to an embodiment of this application when no dark spots appear;

[0023] Figure 4 This is a schematic diagram of a dark spot within a first effective detection area according to an embodiment of this application;

[0024] Figure 5 This is a schematic diagram showing a dark spot not located within the first effective detection area according to an embodiment of this application.

[0025] Figure Labels

[0026] 1: First infrared laser generating unit; 2: First spot detection unit; 3: Second infrared laser generating unit; 4: Second spot detection unit; 5: Print head; 6: Nozzle row; 7: Ink droplet; 8: Dark spot; 9: Projection point of the target nozzle position on the first detection plane; 10: Boundary ray; 11: Center position of the first spot image. Detailed Implementation

[0027] 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.

[0028] In related technologies, detection solutions for printer nozzle clogging and abnormal ejection can be mainly summarized into the following categories:

[0029] The first type is an indirect detection scheme based on print result analysis. This scheme typically controls the print head to output a preset test pattern and then manually observes or performs image processing analysis on the print results to determine whether there is nozzle blockage or ejection abnormality. However, this scheme relies on post-processing analysis of the print results, resulting in a long detection cycle and making real-time detection impossible. Furthermore, the print results are easily affected by factors such as paper quality, ambient lighting, and image processing accuracy. When only a slight nozzle blockage or ejection angle deviation occurs, it is difficult to identify in a timely and accurate manner, easily leading to missed detections or misjudgments. Moreover, it cannot directly reflect the instantaneous state information during the ejection process.

[0030] The second type is a comprehensive detection scheme based on multiple sampling or multi-stage analysis. This scheme improves detection accuracy by sampling the nozzle spraying situation multiple times at different times or locations and combining multiple sets of detection data for comprehensive judgment. However, this type of scheme usually requires multiple triggering of spraying or multiple acquisition of optical signals, making the detection process complex and time-consuming. At the same time, it is difficult to ensure the consistency between different samples, and it is easily affected by environmental disturbances and changes in equipment status, resulting in large data dispersion and thus affecting the reliability of the final judgment result.

[0031] Clearly, in related technologies, neither indirect detection methods based on printing results nor comprehensive detection methods relying on multiple sampling can accurately determine the nozzle clogging status and abnormal spray angle simultaneously in a single detection process. Therefore, the printer nozzle clogging detection device based on multi-optical paths provided in this application controls a first infrared laser generating unit and a second infrared laser generating unit so that the intersection of the first and second infrared lasers is located on the extended line of the central axis of the target nozzle in the target nozzle row. Simultaneously, when a spray command is issued to the target nozzle, the device acquires the first spot signal and the second spot signal. Based on the combined characteristics of the first and second spot signals, it can directly determine whether the target nozzle is clogged in the same detection process. Furthermore, in the case of inkjet spraying, it can further determine whether the inkjet direction has deviated relative to the extended line of the central axis of the target nozzle, thereby identifying whether the inkjet angle is abnormal. Thus, even without multiple detections or multi-stage analysis, a comprehensive determination of the nozzle clogging status and abnormal spray angle can be completed in one go, significantly improving detection efficiency and enhancing the accuracy and reliability of the detection results.

[0032] 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.

[0033] Figure 1 This is a schematic diagram of a multi-optical-path printer head clogging detection device according to an embodiment of this application. Figure 1 As shown, the printer nozzle clogging detection device based on multi-optical paths includes:

[0034] The first infrared laser generating unit 1 is used to generate a first infrared laser, which is parallel to the extension line of the nozzle row of the printhead. For example, in an inkjet printer, the printhead 5 contains multiple nozzle rows 6, and the extension line of the nozzle row 6 is in the X direction. The first infrared laser generating unit 1 can be fixed on the detection bracket so that the first infrared laser emitted by it propagates in the X direction parallel to the extension line of a certain nozzle row 6, thereby forming a direction parallel to the nozzle arrangement direction.

[0035] The first spot detection unit 2 is used to detect the spot signal formed by the first infrared laser on the first detection plane, which is aligned with the normal direction of the nozzle row 6. Specifically, the first detection plane can be set as a YZ plane aligned with the normal direction of the nozzle row 6, such as a linear photodetector array located on the side of the nozzle row 6, used to receive the changes in the projected spot of the first infrared laser in space. When the ink droplet 7 passes through this optical path area during ejection, it will block or scatter the light beam, thereby causing changes in the spot signal.

[0036] The second infrared laser generating unit 3 is used to generate a second infrared laser, which is perpendicular to the first infrared laser in the horizontal direction. For example, the second infrared laser can be emitted along the Y direction to form an orthogonal optical path structure with the first infrared laser propagating along the X direction, thereby constructing a two-dimensional cross detection space.

[0037] The second spot detection unit 4 is used to detect the spot signal formed by the second infrared laser on the second detection plane, which is perpendicular to the second infrared laser. For example, it can be set as an XZ plane perpendicular to the Y-direction beam, used to detect the occlusion change of the ink droplet 7 in another dimension, thereby obtaining the optical response information in the second direction.

[0038] A translation mechanism is used to drive the first infrared laser generating unit 1 and the first spot detection unit 2 to translate synchronously along the array direction of the nozzle row, so that the first infrared laser is adapted to the target nozzle row, and to drive the second infrared laser generating unit 3 and the second spot detection unit 4 to translate synchronously along the nozzle arrangement direction in the nozzle row 6. For example, when there are multiple nozzle rows 6 in the print head 5, the translation mechanism can make the first infrared laser scan different nozzle rows 6. At the same time, the translation mechanism is also used to drive the second infrared laser generating unit and the second spot detection unit to translate synchronously along the nozzle arrangement direction in the nozzle row, so that the second infrared laser can accurately align with the target nozzle position and realize point-by-point detection. In this embodiment, the nozzle row 6 is a linear structure formed by multiple nozzles in the print head arranged along the same straight line direction; the array direction of the nozzle row 6 is the arrangement direction between multiple nozzle rows, and is perpendicular to the arrangement direction of the nozzles in a single nozzle row 6.

[0039] The clogging detection unit controls the movement of the first infrared laser generating unit 1, the second infrared laser generating unit 3, the first spot detection unit 2, and the second spot detection unit 4 via a translation mechanism. This ensures the intersection of the first and second infrared lasers is located on the extended line of the central axis of the target nozzle in the target nozzle row. Upon issuing a spray command to the target nozzle, the unit acquires the first and second spot signals and determines the operating state of the target nozzle based on these signals. The first spot signal is detected by the first spot detection unit at a preset time interval after issuing the spray command; the second spot signal is detected by the second spot detection unit at the same preset time interval. For example, when the ink droplet 7 passes the intersection after being ejected, the first and second spot signals on the first and second detection planes change synchronously. If the nozzle is clogged, the spot signals show no significant change or an abnormal change amplitude. If the spray direction deviates, the first and second spot signals will show inconsistent changes. Finally, the blockage detection unit determines the working state of the target nozzle based on the combined characteristics of the first and second light spot signals, thereby achieving a comprehensive judgment on whether the nozzle is blocked and whether the spraying is normal. Through the above structure and detection method, this embodiment can complete the target nozzle status detection during a single spraying process, improving detection efficiency and enhancing the accuracy and stability of the detection results.

[0040] Optionally, in some embodiments of this application, the preset time interval includes the ejection delay from when the printhead receives the ejection command to when the ink droplet is ejected from the target nozzle, and the flight time required for the ink droplet to move to the intersection of the first infrared laser and the second infrared laser after being ejected from the target nozzle. It should be noted that the preset time interval is a time parameter obtained through pre-calibration measurement under normal operating conditions of the target nozzle. Specifically, under a baseline state where the printhead is unblocked and the ejection direction is normal, the target nozzle is controlled to perform an ejection operation. The ejection delay from when the printhead receives the ejection command to when the ink droplet is actually ejected, and the flight time required for the ink droplet to move to the intersection of the first infrared laser and the second infrared laser after being ejected from the nozzle, are obtained through experimental measurement or calibration. These two values ​​are then superimposed to determine the preset time interval. For example, in one specific embodiment, multiple ejection tests can be performed on the target nozzle during the factory calibration or maintenance calibration phase. The ejection delay and ink droplet flight time are obtained through high-speed sampling or optical measurement, and the average value or statistically stable value is taken as the preset time interval, thereby forming a standard detection timing parameter that matches the characteristics of the printhead.

[0041] Optionally, in some embodiments of this application, the wavelength range of the first and second infrared lasers is 750nm to 3000nm, which covers the near-infrared to mid-far-infrared range. For example, infrared laser light sources such as 850nm, 980nm, 1550nm, or 2000nm can be selected. Taking a specific embodiment as an example, a 1550nm infrared laser is used as the light source for both the first and second infrared laser generating units. It has strong environmental anti-interference capabilities and can maintain stable beam propagation and detection signal output even when there is ink mist, dust, or changes in ambient light inside the printer, thereby improving the stability of the detection system.

[0042] The cross-sections of the first and second infrared lasers are circular or rectangular. For example, when a fiber-coupled laser is used, its output spot is usually an approximately circular Gaussian distribution spot; when a line laser shaping structure or a cylindrical lens beam expanding structure is used, a rectangular spot can be formed to adapt to the linear arrangement structure of the nozzle row, thereby improving the uniformity of coverage of the spray area.

[0043] The diameter of the spot image formed by the first infrared laser on the first detection plane is larger than the maximum diameter of the ink droplet ejected from the target nozzle, and the diameter of the spot image formed by the second infrared laser on the second detection plane is larger than the maximum diameter of the ink droplet ejected from the target nozzle. For example, assuming the maximum diameter of the ink droplet ejected by the target nozzle under normal operating conditions is 20 μm, the diameter of the spot formed by the first infrared laser on the first detection plane can be set to a range of 100 μm to 300 μm, so that even if the ink droplet deviates slightly during flight, it can still fall into the effective detection area of ​​the spot, thereby ensuring that optical obstruction or scattering changes can be stably captured. Similarly, the diameter of the spot image formed by the second infrared laser on the second detection plane is also set to a range larger than the maximum diameter of the ink droplet, for example, also 100 μm to 300 μm, to ensure that the detection in the second direction also has sufficient coverage margin.

[0044] In one specific embodiment, the clogging detection unit is further configured to determine a first intensity difference between the first light spot signal and a pre-acquired third light spot signal, and a second intensity difference between the second light spot signal and a pre-acquired fourth light spot signal. If both the first intensity difference and the second intensity difference are greater than a preset threshold, the target nozzle is determined to be in a normal spraying state. For example, when the target nozzle is in a normal spraying state, the ink droplets fall stably along the central axis, which will simultaneously produce a balanced blocking or scattering effect on the first infrared laser and the second infrared laser, causing both the first intensity difference and the second intensity difference to exceed the preset threshold. This indicates that both optical paths have detected stable ink droplet passage disturbances, thereby determining that the target nozzle is in a normal spraying state.

[0045] In this embodiment, the third spot signal is the spot signal formed by the first infrared laser on the first detection plane when no ink droplets pass through the first infrared laser; the fourth spot signal is the spot signal formed by the second infrared laser on the second detection plane when no ink droplets pass through the second infrared laser. Since both the third and fourth spot signals originate from a reference state without ink droplet interference, the intensity difference calculation has a clear physical reference, thereby improving the stability and consistency of the detection results.

[0046] If both the first intensity difference and the second intensity difference are less than or equal to the preset threshold, the target nozzle is determined to be in a blocked state. For example, when the target nozzle is blocked, since the ink droplets cannot be ejected normally, the first infrared laser and the second infrared laser are no longer interfered with by the ink droplets. The difference between the current spot signal and the reference spot signal is significantly reduced, so that both the first intensity difference and the second intensity difference are less than or equal to the preset threshold, thereby enabling a quick determination that the target nozzle is blocked.

[0047] If the first intensity difference is greater than the preset threshold and the second intensity difference is less than or equal to the preset threshold, it is determined that the spray angle of the target nozzle in the straight line direction where the target nozzle row is located is abnormal.

[0048] If the second intensity difference is greater than the preset threshold and the first intensity difference is less than or equal to the preset threshold, it is determined that the spray angle of the target nozzle in the direction perpendicular to the straight line where the target nozzle row is located is abnormal.

[0049] For example, when the target nozzle has an abnormal spray angle, the ink droplets deviate from the central axis of the target nozzle, resulting in an asymmetry in the influence on the first and second infrared lasers. For instance, when the spray direction is biased towards the straight line of the target nozzle row, the ink droplets mainly pass through the first infrared laser, causing the first intensity difference to be greater than a preset threshold, while the second infrared laser is almost unaffected, with its second intensity difference being less than or equal to the preset threshold, thus indicating an abnormal angle along the nozzle row direction. Conversely, when the spray direction deviates from and is perpendicular to the straight line of the nozzle row, only the second infrared laser is significantly affected, resulting in a second intensity difference greater than the preset threshold and a first intensity difference less than or equal to the preset threshold, thus indicating an abnormal spray angle in the vertical direction.

[0050] For example, suppose a target nozzle in an actual printing device is selected for online detection. First, a baseline acquisition is performed under ink-free conditions. At this time, neither the first nor the second infrared laser is interfered with by ink droplets, forming stable light spots on their respective detection planes, and the third and fourth spot signals are acquired. Assume the light intensity values ​​under this baseline state are: the first baseline light intensity is 100 (units can be grayscale values ​​or photoelectric conversion values), and the second baseline light intensity is 100. Subsequently, a spray command is issued to the target nozzle, and the first and second spot signals are acquired synchronously after a preset time interval. For example, in a normal spray situation, the ink droplet falls stably along the central axis and passes through the first and second infrared lasers in sequence. At this time, both laser beams are blocked or scattered by the ink droplets, resulting in a decrease in light intensity. Assuming the detected first spot signal is 70 and the second spot signal is 72, the corresponding first intensity difference is 30, and the second intensity difference is 28. If the preset threshold is 20, then both intensity differences are greater than the threshold, indicating that both optical paths detect the ink droplet disturbance, thus determining that the target nozzle is in a normal spraying state. Further, in another operating condition, if the target nozzle is clogged, for example, due to impurities inside the nozzle preventing ink droplets from being ejected, then after issuing the spray command, neither the first nor the second infrared laser will be affected by the ink droplets. Assuming the detected first spot signal is 98 and the second spot signal is 99, then the first intensity difference is 2 and the second intensity difference is 1, both less than the preset threshold of 20, thus directly determining that the nozzle is clogged. For another example, in the case of an abnormal spray angle, assuming the target nozzle's spray direction deviates along the straight line of the nozzle row, the ink droplet only passes through the first infrared laser path and does not enter the detection area of ​​the second infrared laser. The detection result might be: the first spot signal is 68 (intensity difference 32), and the second spot signal is 97 (intensity difference 3). Since the first intensity difference is greater than the threshold and the second intensity difference is less than the threshold, it can be determined that the nozzle has an abnormal spray angle in the nozzle row direction. Similarly, if the spray direction deviates to the direction perpendicular to the nozzle, the ink droplet only affects the second infrared laser. For example, if the first spot signal is detected as 96 (difference 4) and the second spot signal is 69 (difference 31), the second intensity difference is greater than the threshold while the first intensity difference is less than the threshold, thus determining that the nozzle has an abnormal spray angle in the vertical direction.

[0051] Based on the above, it can be seen that the embodiments of this application can simultaneously complete the identification of three key states of the target nozzle within a single spray detection cycle, including blockage state identification, angular offset identification along the nozzle row direction, and angular offset identification in the vertical direction. Compared with traditional schemes that require multiple frame sampling or repeated detection, this scheme achieves the technical effect of "one detection, multiple state determination" through spatially orthogonally distributed dual optical path information fusion.

[0052] In another specific embodiment, the blockage detection unit is further configured to acquire a corresponding first spot image based on the first spot signal and a corresponding second spot image based on the second spot signal, and to determine whether dark spots appear in the first spot image and the second spot image respectively. In the spot image, a local low-intensity area is formed by the ink droplet blocking, absorbing, or scattering local infrared light when passing through the infrared laser path, resulting in a significant reduction in light intensity in that area compared to the background reference. The dark spot is a local light intensity reduction area in the spot image caused by the ink droplet passing through the infrared laser path; the dark spot is characterized by a local grayscale reduction or intensity depression in the image. For example, when the background grayscale value of the spot is about 200 (0-255 grayscale range), the grayscale value of the corresponding area after the ink droplet passes through can drop to 120 or even lower, thus forming a clearly identifiable dark spot in the spot image. The clogging detection unit acquires and analyzes two light spot images to detect the existence of such local grayscale reduction areas. When dark spots are detected in both the first and second light spot images, it can be determined that the ink droplet is simultaneously traversing two light paths, thereby confirming that the target nozzle is in a normal spraying state.

[0053] If dark spots appear in both the first and second spot images, the target nozzle is determined to be in a normal spraying state. For example, when the target nozzle is in a normal spraying state, ink droplets fall steadily along a preset spraying path and sequentially pass through the detection areas of the first and second infrared lasers, thereby forming identifiable dark spot features in the first and second spot images, respectively. At this time, since ink droplets sequentially pass through both optical paths, dark spots appear in both the first and second spot images, thus determining that the target nozzle is in a normal spraying state.

[0054] If no dark spots appear in either the first or second spot image, the target nozzle is determined to be blocked. For example, when the target nozzle is blocked, since there are no ink droplets inside the nozzle or the ink droplets cannot be ejected normally, the infrared laser path is no longer blocked by matter. Therefore, both the first and second spot images maintain a uniform light intensity distribution and do not show any dark spot areas with reduced local light intensity, thus it can be determined that the target nozzle is blocked.

[0055] Dark spot 8 appears in the first light spot image (see...) Figure 2 And no dark spots appeared in the second spot image (such as...). Figure 3 In the case shown), the spray angle of the target nozzle in the straight line direction of the nozzle row is determined to be abnormal.

[0056] If no dark spots appear in the first spot image but dark spots appear in the second spot image, then it is determined that the spray angle of the target nozzle in the direction perpendicular to the straight line where the target nozzle row is located is abnormal.

[0057] For example, when the spray angle is abnormal, the trajectory of the ink droplet will deviate from the preset center path, causing it to pass through only one of the infrared laser beams. For instance, when the spray direction shifts along the straight line of the nozzle row, the ink droplet only passes through the first infrared laser detection area, resulting in a dark spot in the first spot image. The second spot image, however, does not show a dark spot because the ink droplet has not passed through it, thus indicating an abnormal spray angle along the nozzle row direction. Conversely, when the spray direction shifts perpendicular to the straight line of the nozzle row, the ink droplet only passes through the second infrared laser path, resulting in a dark spot in the second spot image while the first spot image remains clear, indicating an abnormal spray angle in the vertical direction.

[0058] In another specific embodiment, see Figure 4 The clogging detection unit is further configured to, when the target nozzle is determined to be in a normal spraying state, determine whether the target nozzle has a spraying direction deviation in the straight line direction of the nozzle row based on the position of the dark spot 8 in the first spot image and the preset first effective detection area of ​​the first spot image. The line connecting the projection point 9 of the target nozzle position on the first detection plane and the center position 11 of the first spot image formed by the first infrared laser on the first detection plane is used as the first reference axis to characterize the alignment relationship between the ideal spraying path and the optical detection center. Two boundary rays 10 extend from both sides of the first reference axis, with an angle no greater than a preset spraying deviation angle, thereby constructing an allowable deviation angle range centered on the ideal spraying path. The first effective detection area is the intersection of the area surrounded by the boundary rays and the projection area of ​​the first spot image on the first detection plane, used to characterize the reasonable position range where the ink droplet should have a dark spot within the allowable error range of the normal process.

[0059] Among them, see Figure 4 If the position of the dark spot 8 in the first spot image is located within a preset first effective detection area of ​​the first spot image, it is determined that the target nozzle has no spray direction deviation in the straight line direction of the nozzle row. For example, when the target nozzle is working normally, the ink droplet may be slightly deviated during its fall due to fluid disturbances or airflow disturbances, but it should still fall within the spatial range defined by the preset spray deviation angle. In this case, after the ink droplet passes through the first infrared laser, the position of the dark spot 8 formed in the first spot image is still located within the first effective detection area, thus determining that the target nozzle has not undergone significant spray direction deviation in the straight line direction of the nozzle row.

[0060] like Figure 5 As shown, when the position of the dark spot 8 in the first light spot image is outside the preset first effective detection area of ​​the first light spot image, it is determined that the target nozzle has a spray direction deviation in the straight line direction of the nozzle row. For example, if the target nozzle deviates at a large angle or the spray direction deviation is caused by uneven release of local blockage during the spraying process, the ink droplet trajectory will deviate from the first reference axis by a large angle range. For example, when the spray direction deviates at a large angle along the nozzle row direction, the dark spot 8 formed after the ink droplet passes through the first infrared laser will deviate from the boundary of the first effective detection area as a whole and fall outside the area. At this time, it is determined that the position of the dark spot 8 exceeds the tolerance range corresponding to the preset spray deviation angle, thereby determining that the target nozzle has a spray direction deviation in the straight line direction of the nozzle row.

[0061] Based on the above, this embodiment integrates the determination of whether the target nozzle is clogged and the determination of whether the jet direction is deviated into a single ink droplet ejection process: during a single ejection triggering process, whether a blockage is detected by the presence of dark spots in the dual optical paths, the approximate direction of jet direction deviation by the distribution of dark spots in different spot images, and further, the precise determination of whether the jet angle exceeds the tolerance range by the positional relationship of the dark spots relative to the first effective detection area. Thus, only a single ink droplet crossing the detection area is needed to simultaneously acquire multi-dimensional state information, achieving the technical effect of "one ejection, multiple problem determinations." Compared to existing technologies that require multiple ejection samplings, repeated detections, or reliance on complex post-processing algorithms, this application significantly reduces the number of detections and computational complexity by combining spatial geometric constraints with spot image features. This not only significantly improves detection efficiency but also effectively reduces the cumulative errors and inconsistencies caused by multiple samplings, thereby enhancing the overall stability and reliability of the detection system.

[0062] Preferably, in some other embodiments of this application, the blockage detection unit is further configured to, when determining that the target nozzle is in a normal spraying state, determine whether there is a spraying direction deviation in the direction perpendicular to the straight line where the target nozzle and the nozzle row are located, based on the position of the dark spot in the second spot image and the preset second effective detection area of ​​the second spot image. The second reference axis is defined as the line connecting the projection point of the target nozzle position on the second detection plane and the center position of the second spot image formed by the second infrared laser on the second detection plane. Two boundary rays with an angle not greater than a preset spraying deviation angle extend from both sides of the second reference axis. The second effective detection area is the intersection of the area surrounded by the boundary rays and the projection area of ​​the second spot image on the second detection plane.

[0063] Specifically, if the position of the dark spot in the second spot image is located within a preset second effective detection area of ​​the second spot image, it is determined that there is no spray direction deviation in the direction perpendicular to the straight line where the target nozzle is located. For example, when the target nozzle is working normally and the spray is stable, the ink droplet moves along the central axis of the nozzle. Although it may be slightly deflected by airflow disturbance, its deflection angle is usually less than the preset spray deviation angle. Therefore, after passing through the second infrared laser, the position of the dark spot formed in the second spot image is still located within the second effective detection area. Based on this, it can be determined that the target nozzle has not experienced a spray direction deviation in the direction perpendicular to the straight line where the nozzle is located.

[0064] If the dark spot in the second spot image is located outside the preset second effective detection area of ​​the second spot image, it is determined that there is a jetting direction offset in the direction perpendicular to the straight line where the target nozzle is located. For example, due to internal structural deviations, local contamination, or uneven drive, the initial velocity direction of the ink droplets may deviate, causing the ink droplet trajectory to deviate from the second reference axis at a large angle, thus causing the dark spot formed in the second spot image to fall outside the second effective detection area. In this case, by determining that the dark spot has crossed the boundary, it can be determined that there is a jetting direction offset of the target nozzle in the direction perpendicular to the nozzle row.

[0065] Preferably, in some other embodiments of this application, the blockage detection unit is further configured to, when it is determined that the target nozzle is in a normal spraying state, extract image features from the first spot image and the second spot image respectively to obtain the first spot image features and the second spot image features;

[0066] The first spot image features and the second spot image features are respectively input into a pre-trained image recognition model to obtain the first jet angle and the second jet angle.

[0067] Wherein, the first injection angle is the injection angle of the target nozzle in the direction of the straight line where the nozzle row is located, and the second injection angle is the injection angle of the target nozzle in the direction perpendicular to the straight line where the nozzle row is located;

[0068] The first and second spray angles are compared with preset angle tolerance ranges. If the first spray angle is greater than the preset angle tolerance range, it is determined that the target nozzle has a spray direction deviation in the direction of the nozzle row. If the second spray angle is greater than the preset angle tolerance range, it is determined that the target nozzle has a spray direction deviation in the direction perpendicular to the direction of the nozzle row. For example, in a specific embodiment, assuming the preset angle tolerance range is ±2°, when the first spray angle output by the model is 1.2° and the second spray angle is 0.8°, it can be determined that the nozzle spray is within the normal range. However, when the first spray angle reaches 3.5°, it can be clearly identified that there is a significant deviation in the direction of the nozzle row.

[0069] The first spot image feature and the second spot image feature both include the center position coordinates, area parameters and local gray level decrease of the dark spot. The local gray level decrease is the difference between the average pixel gray level of the dark spot in the corresponding spot image and the average pixel gray level of the spot area other than the dark spot.

[0070] The image recognition model is pre-trained based on training data, which includes the features of the first spot image and the second spot image collected under different known spray angle conditions, as well as the corresponding spray angle annotation information.

[0071] By employing the aforementioned detection method combining image feature extraction and image recognition models, this embodiment, based on the premise that the target nozzle is in a normal spraying state, can simultaneously quantitatively acquire and determine anomalies in two orthogonal spraying directions during a single ink droplet spraying process. Specifically, the first and second spot image features both originate from the spot images formed when the same ink droplet traverses the intersection region of the first and second infrared lasers. Without requiring multiple spraying samples or repeated detections, the model can directly output the first and second spraying angles, thereby acquiring the spraying state information of the target nozzle in both the nozzle row direction and its perpendicular direction in a single operation. Compared to existing detection methods that typically require multiple samplings, directional analysis, or post-processing to reconstruct the spray trajectory, this embodiment, through simultaneous dual-optical-path acquisition and feature fusion, provides multi-dimensional information input simultaneously from a single spraying action, enabling bidirectional quantitative determination of the spraying angle. This significantly reduces the time consumption and number of sprays during the detection process and avoids data inconsistency issues caused by multiple samplings, thereby improving the stability and consistency of the detection results.

[0072] Optionally, in some embodiments of this application, the clogging detection unit is further configured to, when it is determined that the target nozzle is in a normal spraying state, acquire the dark spot features of the first spot image or the second spot image, and determine whether the ink droplet corresponding to the dark spot is rotating based on the dark spot features;

[0073] The features of the dark spot include: the roundness of the dark spot outline, the aspect ratio, the smoothness of the dark spot edge, and the skewness of the edge curve; among them, roundness can be calculated by the relationship between the dark spot area and the perimeter, and is used to measure whether the shape of the dark spot is close to an ideal circle; the aspect ratio can be obtained by the ratio of the major axis to the minor axis of the smallest bounding rectangle of the dark spot, and is used to characterize whether the dark spot has a stretching deformation; the edge smoothness can be evaluated by the curvature change or the degree of high frequency fluctuation of the edge curve, and is used to reflect whether there is irregular disturbance at the ink droplet boundary.

[0074] The degree of skewing of the edge curve of the dark spot is obtained in the following way:

[0075] Based on the extracted edge curve coordinates of the dark spot, the edge curve is fitted, and the angle between the edge curve and the reference axis from the nozzle position to the center of the corresponding first or second spot image is calculated. This angle is then used as a quantitative value for the degree of skewness of the edge curve. The larger the angle, the more significant the deflection of the dark spot morphology relative to the ideal jet direction, thus reflecting the possibility of rotation or attitude instability of the ink droplet during flight. For example, when the target nozzle is jetting normally and the ink droplet attitude is stable, the ink droplet usually maintains an approximately spherical or axisymmetric structure. The dark spot formed after passing through the laser beam path is also nearly circular or a regular ellipse, with high roundness, an aspect ratio close to 1, and a small edge skew angle. However, when the ink droplet rotates or is subjected to asymmetric perturbation during jetting, its shape may be stretched or tilted, causing the dark spot to exhibit obvious asymmetric characteristics, such as an increased aspect ratio, uneven edges, and deviation of the main axis from the reference axis. This significantly increases the degree of skewness of the calculated edge curve, indicating that the ink droplet is rotating.

[0076] This embodiment can simultaneously complete clogging identification, jet angle deviation determination, and ink droplet rotation status analysis with a single ink drop, realizing a full-dimensional detection capability from "whether it is sprayed" to "whether the spray is accurate and whether the ink droplet is rotating", thus improving detection efficiency.

[0077] In this embodiment, determining whether the ink droplet corresponding to the dark spot is rotating based on the dark spot features specifically includes: comparing the dark spot features with the dark spot features in the normal state. The comparison includes: comparing the difference between the roundness of the dark spot outline and the roundness in the normal state with a preset roundness tolerance; comparing the difference between the aspect ratio of the dark spot outline and the aspect ratio in the normal state with a preset aspect ratio tolerance; comparing the difference between the smoothness of the dark spot edge and the smoothness in the normal state with a preset smoothness tolerance; comparing the difference between the skewness of the dark spot edge curve and the skewness in the normal state with a preset skewness tolerance; if the difference of any dark spot feature exceeds the corresponding preset tolerance, it is determined that the ink droplet is rotating; if all dark spot features are within the corresponding preset tolerance range, it is determined that the ink droplet is not rotating.

[0078] In detail, in this embodiment, determining whether the ink droplet corresponding to the dark spot is rotating based on the dark spot feature specifically includes comparing the acquired dark spot feature with the dark spot feature in the normal state, and making a determination based on the comparison result.

[0079] The dark spot characteristics in the normal state are standard characteristic parameters obtained in advance through calibration experiments under the condition that the nozzle is working normally and the ink droplets are not rotating. These parameters include normal state roundness, normal state aspect ratio, normal state smoothness, and normal state skewness. The preset roundness tolerance, preset aspect ratio tolerance, preset smoothness tolerance, and preset skewness tolerance are allowable deviation ranges preset according to the actual equipment accuracy and printing requirements. Specific comparison methods include:

[0080] First, the difference between the roundness of the dark spot contour and the roundness in the normal state is compared with a preset roundness tolerance. For example, the normal roundness is 0.95, and the preset roundness tolerance is ±0.05; if the actual detected roundness of the dark spot is 0.88, the difference is 0.07, which is greater than the preset roundness tolerance of 0.05, thus the roundness feature is determined to be abnormal. Second, the difference between the aspect ratio of the dark spot contour and the aspect ratio in the normal state is compared with a preset aspect ratio tolerance. For example, the normal aspect ratio is 1.05, and the preset aspect ratio tolerance is ±0.10; if the actual detected aspect ratio is 1.22, the difference is 0.17, which is greater than the preset aspect ratio tolerance, thus the aspect ratio feature is determined to be abnormal. Third, the difference between the smoothness of the dark spot edge and the smoothness in the normal state is compared with a preset smoothness tolerance. For example, the smoothness parameter in the normal state is 5, and the preset smoothness tolerance is ±3. If the detected value is 10, the difference is 5, which is greater than the tolerance of 3, so the smoothness feature is judged to be abnormal. In addition, the difference between the skewness of the dark spot edge curve and the skewness in the normal state is compared with the preset skewness tolerance. For example, the skewness in the normal state is 0.5°, and the preset skewness tolerance is ±2°. If the detected value is 4°, the difference is 3.5°, which exceeds the preset skewness tolerance range, so the skewness feature is judged to be abnormal. In the above comparison process, as long as the difference of any dark spot feature exceeds the corresponding preset tolerance range, it can be determined that the ink droplet of the specified nozzle is rotating. That is to say, this embodiment adopts the judgment logic of "any feature exceeding the tolerance determines rotation", thereby improving the sensitivity to ink droplet posture abnormalities. Conversely, when all dark spot features are within the corresponding preset tolerance range, that is, when the roundness, aspect ratio, edge smoothness, and edge curve skewness of the dark spot outline do not exceed their respective tolerance ranges, it is judged that the ink droplet of the specified nozzle is not rotating. Through the aforementioned multi-feature comparison mechanism, a comprehensive determination of whether an ink droplet is rotating is achieved, rather than relying solely on a single feature, thereby improving the accuracy and reliability of the judgment. Since rotating ink droplets may exhibit different morphological changes under different operating conditions—for example, reduced roundness with little change in aspect ratio, or increased skewness with minimal change in roundness—the use of multi-parameter parallel comparison effectively avoids missed or false judgments. Simultaneously, this judgment is still based on the first light spot image, which originates from a single spraying action of the designated nozzle. Therefore, in a single spraying action, not only can it be determined whether the nozzle is clogged and whether there is a spray direction deviation, but it can also further determine whether the ink droplet is rotating, achieving multi-dimensional synchronous detection of the nozzle's operating state without the need for multiple sprays or additional detection devices.

[0081] Optionally, in some embodiments of this application, the clogging detection unit is further used to dynamically correct the preset time interval based on the peak occurrence times of the first and second spot signals obtained during multiple historical ejection processes, thereby achieving adaptive adjustment according to the actual flight state of the ink droplets. Specifically, after the printhead sends an ejection command to the target nozzle, the target nozzle ejects ink droplets, which fly along a preset path to the intersection of the first and second infrared lasers. The clogging detection unit collects the spot signals in real time through the first and second spot detection units and records the peak occurrence time of the spot signal during each ejection process. The peak value of the spot signal refers to the point of maximum change in light intensity caused by the infrared light being blocked, absorbed, or scattered when the ink droplet passes through the optical path, usually manifested as the lowest point or the maximum drop value on the spot signal curve. Based on the spot peak data from multiple ejections, the clogging detection unit calculates the average value and standard deviation of the peak occurrence times and compares them with the originally set preset time interval. If a systematic deviation is detected between the average peak occurrence time and the original preset time interval, or if the peak occurrence time fluctuates beyond a preset threshold, the clogging detection unit dynamically adjusts the preset time interval to more closely approximate the actual arrival time of the ink droplets in the detection area. For example, assuming the original preset time interval is 10 milliseconds (i.e., the sampling time interval from the issuance of the ejection command to the detection of the spot signal is 10 milliseconds), and during 20 consecutive ejections, the average occurrence time of the first spot signal peak is 11 milliseconds, and the average occurrence time of the second spot signal peak is 11.2 milliseconds, the clogging detection unit determines that the actual peak is approximately 1 to 1.2 milliseconds later than the original preset time. Therefore, it dynamically adjusts the preset time interval to 11 milliseconds to ensure accurate acquisition of the spot signal as the ink droplets pass through the optical path in the next ejection detection. This adaptive mechanism not only corrects for average deviations but also responds in real time to changes in ink droplet flight time caused by variations in ink viscosity, temperature fluctuations, or nozzle aging. For example, when the ink temperature rises and the viscosity decreases, the droplet flight speed increases and the peak time will appear earlier; the clogging detection unit can automatically shorten the preset time interval based on historical data to keep the spot signal acquisition synchronized with the droplet arrival time, thereby avoiding misjudgment of nozzle status caused by time deviation.

[0082] In addition, this application embodiment also provides a printing device, including: a printhead, and a multi-optical-path printer printhead clogging detection device similar to the one described in the above embodiment.

[0083] The printing device of this application, by setting up a first infrared laser generation unit, a second infrared laser generation unit, and corresponding spot detection units, and combining them with a translation mechanism, enables two orthogonal infrared laser beams to simultaneously detect at the intersection of the target nozzle, achieving multi-dimensional information acquisition of the same ejection event. During the same ejection triggering process, the working state of the target nozzle can be simultaneously determined based on the first and second spot signals, including clogging status, normal ejection status, and ejection angle anomalies in the straight line direction of the nozzle row and the direction perpendicular to the nozzle row. Furthermore, it can acquire various detection results such as ejection offset, ejection angle values, and droplet rotation characteristics. Thus, it achieves simultaneous analysis of the same droplet behavior through multi-optical path collaboration within a single ejection command and a single detection window, enabling "one-time detection, multi-dimensional output," significantly improving the efficiency and information integrity of printhead clogging detection and ejection status identification.

[0084] 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.

[0085] 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.

[0086] 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.

[0087] 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 clogging detection device for a printer printhead based on a multi-optical path, characterized in that, include: A first infrared laser generating unit is used to generate a first infrared laser, which is parallel to the extension line of the nozzle row of the print head. The first spot detection unit is used to detect the spot signal formed by the first infrared laser on the first detection plane, and the first detection plane is aligned with the normal direction of the nozzle row. The second infrared laser generating unit is used to generate a second infrared laser, which is perpendicular to the first infrared laser in the horizontal direction. The second spot detection unit is used to detect the spot signal formed by the second infrared laser on the second detection plane, which is perpendicular to the second infrared laser. The translation mechanism is used to drive the first infrared laser generating unit and the first spot detection unit to translate synchronously along the array direction of the nozzle row so that the first infrared laser is adapted to the target nozzle row, and to drive the second infrared laser generating unit and the second spot detection unit to translate synchronously along the nozzle arrangement direction in the nozzle row. The blockage detection unit is used to control the movement of the first infrared laser generating unit, the second infrared laser generating unit, the first spot detection unit, and the second spot detection unit via a translation mechanism, so that the intersection of the first infrared laser and the second infrared laser is located on the extension line of the central axis of the target nozzle in the target nozzle row. When a spray command is issued to the target nozzle, the unit acquires the first spot signal and the second spot signal, and determines the working state of the target nozzle based on the first spot signal and the second spot signal. The first spot signal is detected by the first spot detection unit at a preset time interval after the spray command is issued; the second spot signal is detected by the second spot detection unit at a preset time interval after the spray command is issued.

2. The printer nozzle clogging detection device based on multi-optical paths according to claim 1, characterized in that, The preset time interval includes the ejection delay when the printhead receives the ejection command to the target nozzle and the time required for the ink droplet to travel from the target nozzle to the intersection of the first infrared laser and the second infrared laser.

3. The clogging detection device for printer nozzles based on multi-optical paths according to claim 2, characterized in that, The wavelength range of the first infrared laser and the second infrared laser is 750nm to 3000nm. The cross-section of the first infrared laser and the second infrared laser is circular or rectangular. The diameter of the spot image formed by the first infrared laser on the first detection plane is larger than the maximum diameter of the ink droplet ejected from the target nozzle. The diameter of the spot image formed by the second infrared laser on the second detection plane is larger than the maximum diameter of the ink droplet ejected from the target nozzle.

4. The clogging detection device for a printer printhead based on multiple optical paths according to any one of claims 1-3, characterized in that, The blockage detection unit is further configured to determine a first intensity difference between the first spot signal and a pre-acquired third spot signal, and a second intensity difference between the second spot signal and a pre-acquired fourth spot signal; and determine that the target nozzle is in a normal spraying state when both the first intensity difference and the second intensity difference are greater than a preset threshold. If both the first intensity difference and the second intensity difference are less than or equal to the preset threshold, the target nozzle is determined to be in a blocked state. If the first intensity difference is greater than the preset threshold and the second intensity difference is less than or equal to the preset threshold, it is determined that the spray angle of the target nozzle in the straight line direction where the target nozzle row is located is abnormal. If the second intensity difference is greater than the preset threshold and the first intensity difference is less than or equal to the preset threshold, it is determined that the spray angle of the target nozzle in the direction perpendicular to the straight line where the target nozzle row is located is abnormal. The third spot signal is the spot signal formed on the first detection plane by the first infrared laser when no ink droplet passes through the first infrared laser; The fourth spot signal is the spot signal formed on the second detection plane by the second infrared laser when no ink droplet passes through the second infrared laser.

5. The clogging detection device for a printer printhead based on multiple optical paths according to any one of claims 1-3, characterized in that, The blockage detection unit is further configured to acquire a corresponding first spot image based on the first spot signal, and acquire a corresponding second spot image based on the second spot signal, and determine whether dark spots appear in the first spot image and the second spot image respectively. The dark spot is a local light intensity reduction area caused by the ink droplet passing through the infrared laser path in the spot image. If dark spots appear in both the first and second spot images, then the target nozzle is determined to be in a normal spraying state. If no dark spots appear in either the first or second spot image, then the target nozzle is determined to be blocked. If a dark spot appears in the first spot image and no dark spot appears in the second spot image, then it is determined that the spray angle of the target nozzle in the straight line direction where the nozzle row is located is abnormal. If no dark spots appear in the first spot image but dark spots appear in the second spot image, then it is determined that the spray angle of the target nozzle in the direction perpendicular to the straight line where the target nozzle row is located is abnormal.

6. The clogging detection device for a printer nozzle based on a multi-optical path according to claim 5, characterized in that, The blockage detection unit is further configured to, when determining that the target nozzle is in a normal spraying state, determine whether the target nozzle has a spraying direction deviation in the straight line direction where the nozzle row is located, based on the position of the dark spot in the first spot image and the preset first effective detection area of ​​the first spot image. The first reference axis is defined as the line connecting the projection point of the target nozzle position on the first detection plane and the center position of the first spot image formed by the first infrared laser on the first detection plane. Two boundary rays extend from both sides of the first reference axis at an angle not greater than a preset spraying deviation angle with respect to the first reference axis. The first effective detection area is the intersection of the area surrounded by the boundary rays and the projection area of ​​the first spot image on the first detection plane. Wherein, if the position of the dark spot in the first spot image is located within a preset first effective detection area of ​​the first spot image, it is determined that the target nozzle does not have a spray direction offset in the straight line direction of the nozzle row; If the dark spot is located outside the preset first effective detection area of ​​the first spot image, it is determined that the target nozzle has a spray direction offset in the straight line direction of the nozzle row.

7. The clogging detection device for a printer printhead based on a multi-optical path according to claim 5, characterized in that, The blockage detection unit is further configured to, when determining that the target nozzle is in a normal spraying state, determine whether there is a spraying direction deviation in the direction perpendicular to the straight line where the target nozzle and the nozzle row are located, based on the position of the dark spot in the second spot image and the preset second effective detection area of ​​the second spot image. The second reference axis is defined as the line connecting the projection point of the target nozzle position on the second detection plane and the center position of the second spot image formed by the second infrared laser on the second detection plane. Two boundary rays with an angle not greater than a preset spray deviation angle extend from both sides of the second reference axis. The second effective detection area is the intersection of the area surrounded by the boundary rays and the projection area of ​​the second spot image on the second detection plane. Wherein, if the position of the dark spot in the second spot image is located within a preset second effective detection area of ​​the second spot image, it is determined that there is no spray direction deviation in the direction perpendicular to the straight line where the target nozzle is located; If the dark spot is located outside the preset second effective detection area of ​​the second spot image, it is determined that there is a spray direction offset in the direction perpendicular to the straight line where the target nozzle is located.

8. The clogging detection device for a printer nozzle based on a multi-optical path according to claim 5, characterized in that, The blockage detection unit is further configured to, when it is determined that the target nozzle is in a normal spraying state, extract image features from the first spot image and the second spot image respectively to obtain the first spot image features and the second spot image features. The first spot image features and the second spot image features are respectively input into a pre-trained image recognition model to obtain the first jet angle and the second jet angle. Wherein, the first injection angle is the injection angle of the target nozzle in the direction of the straight line where the nozzle row is located, and the second injection angle is the injection angle of the target nozzle in the direction perpendicular to the straight line where the nozzle row is located; The first injection angle and the second injection angle are compared with a preset angle tolerance range. If the first injection angle is greater than the preset angle tolerance range, it is determined that the target nozzle has an injection direction deviation in the direction of the straight line where the nozzle row is located. If the second injection angle is greater than the preset angle tolerance range, it is determined that the target nozzle has an injection direction deviation in the direction perpendicular to the straight line where the nozzle row is located. The first spot image feature and the second spot image feature both include the center position coordinates, area parameters and local gray level decrease of the dark spot. The local gray level decrease is the difference between the average pixel gray level of the dark spot in the corresponding spot image and the average pixel gray level of the spot area other than the dark spot. The image recognition model is pre-trained based on training data, which includes the features of the first spot image and the second spot image collected under different known spray angle conditions, as well as the corresponding spray angle annotation information.

9. The clogging detection device for a printer nozzle based on a multi-optical path according to claim 5, characterized in that, The clogging detection unit is further configured to, when determining that the target nozzle is in a normal spraying state, acquire the dark spot features of the first spot image or the second spot image, and determine whether the ink droplet corresponding to the dark spot is rotating based on the dark spot features; The features of the dark spot include: the roundness of the dark spot outline, the aspect ratio, the smoothness of the dark spot edge, and the skewness of the edge curve. The degree of skewing of the edge curve of the dark spot is obtained in the following way: Based on the extracted dark spot edge curve coordinates, the edge curve is fitted, and the angle between the edge curve and the reference axis from the nozzle position to the center of the corresponding first spot image or second spot image is calculated. The angle is then used as a quantified value of the skewness of the edge curve.

10. A printing device, characterized in that, include: Print head; The clogging detection device for a printer printhead based on multiple optical paths according to any one of claims 1-9.

Images