Liquid dispensing device and circulation inspection device

Abstract

Further develop existing technologies. [Solution] The liquid discharge device comprises a liquid discharge head having a row of discharge ports arranged in a first direction for discharging liquid, a pressure chamber communicating with the discharge ports and having a pressure generating element that generates pressure for discharging liquid from the discharge ports, a circulation means for circulating the liquid in the pressure chamber between the outside of the pressure chamber and the outside of the pressure chamber, a drive control unit for controlling the operation of the liquid discharge head and the circulation means, which is capable of performing a discharge pause operation to pause the discharge of liquid from the discharge ports, a circulation operation to circulate the liquid in the pressure chamber communicating with the discharge ports between the outside of the pressure chamber and the outside of the pressure chamber, and a printing operation to discharge liquid multiple times from the same discharge port and print a long inspection pattern on a recording medium in a second direction intersecting the first direction, and a circulation inspection means for inspecting the circulation state of the liquid discharge head based on the length of the inspection pattern in the second direction.

Description

Technical Field

[0001] The present invention relates to a liquid ejection device and a circulation inspection device.

Background Art

[0002] As a recording device for recording characters and images on a recording medium, there is a liquid ejection device including a liquid ejection head provided with a liquid ejection port for ejecting a liquid and a pressure chamber communicating with the liquid ejection port. When the liquid ejection port of the liquid ejection head is exposed to the atmosphere, it is known that the volatile components in the liquid evaporate from the liquid ejection port into the atmosphere over time, and the viscosity of the liquid in the liquid ejection port increases. When the viscosity of the liquid in the liquid ejection port increases, the ejection speed of the ejected liquid droplets slows down during liquid ejection, which may affect the landing accuracy. In particular, when the time during which the liquid is not ejected (hereinafter referred to as the rest time) is long, the increase in the viscosity of the liquid becomes significant, and the liquid ejection port may cause ejection failure.

[0003] The thickening of the liquid can be suppressed by circulating the liquid in the pressure chamber. Patent Document 1 discloses an inspection method for ejecting a liquid from a plurality of linearly arranged liquid ejection ports, printing a linear printing pattern extending in the arrangement direction, and inspecting the state of liquid circulation based on this printing pattern.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] An object of the present invention is to further develop the conventional technology.

Means for Solving the Problems

[0006] To achieve the above object, the liquid ejection device of the present invention is A liquid discharge head having a row of discharge ports arranged in a first direction for discharging liquid, and a pressure chamber communicating with the discharge ports and having a pressure generating element for generating pressure to discharge liquid from the discharge ports, A circulation means for circulating the liquid inside the pressure chamber between the outside of the pressure chamber and the outside of the pressure chamber, A drive control unit that controls the operation of the liquid discharge head and the circulation means, the drive control unit capable of performing a discharge pause operation to pause the discharge of liquid from the discharge port, a circulation operation to circulate the liquid in the pressure chamber communicating with the discharge port between the outside of the pressure chamber and the outside of the pressure chamber, and a printing operation to discharge liquid multiple times from the same discharge port to print a long inspection pattern on a recording medium in a second direction intersecting the first direction, A circulation inspection means for inspecting the circulation state of the liquid discharge head based on the length of the inspection pattern in the second direction, It is characterized by having the following features. [Effects of the Invention]

[0007] According to the present invention, the conventional technology can be further developed. [Brief explanation of the drawing]

[0008] [Figure 1] This is a perspective view showing the liquid dispensing head and the element substrate. [Figure 2] This is a perspective view showing a circulatory inspection device. [Figure 3] This is a flowchart showing the inspection flow for the liquid circulation test of the first embodiment. [Figure 4] This is a diagram showing the inspection pattern of the first embodiment. [Figure 5] This is a flowchart showing the evaluation flow of the inspection pattern in the first embodiment. [Figure 6] This is a schematic diagram of the image processing procedure for the inspection pattern of the first embodiment. [Figure 7] This figure shows the length of the inspection pattern in the first embodiment. [Figure 8] This figure shows the inspection pattern of the second embodiment. [Figure 9] This is a flowchart showing the evaluation flow of the inspection pattern in the third embodiment. [Figure 10] This is an explanatory diagram of the method for calculating the grid coordinates of the inspection pattern in the third embodiment. [Figure 11] This is an explanatory diagram of the method for calculating the amount of distortion in the inspection pattern of the third embodiment. [Modes for carrying out the invention]

[0009] The embodiments for carrying out this invention will be described in detail below with reference to the drawings, based on examples. The dimensions, materials, shapes, and relative arrangements of the components described in these embodiments should be appropriately modified depending on the configuration of the device to which the invention is applied and various conditions. In other words, the scope of this invention is not intended to be limited to the following embodiments. Furthermore, not all combinations of features described in these embodiments are necessarily essential to the solutions of this disclosure.

[0010] (Liquid dispensing head) First, the liquid discharge head, which is the object of inspection for the circulation inspection device according to the present invention, will be described. Figures 1(a) to 1(d) show examples of liquid discharge heads 10 that can be inspected by the circulation inspection device.

[0011] Figure 1(a) is a perspective view showing the liquid ejection head 10. The liquid ejection head 10 comprises an element substrate H that ejects ink as a liquid, and a support member 1 that supports the element substrate H. In the liquid ejection head 10 of this example, one element substrate H is arranged for each support member 1. When viewed in the thickness direction of the element substrate H, the element substrate H and the support member 1 are each rectangular in shape.

[0012] An element substrate H is joined to the support member 1 via an adhesive layer (not shown). The support member 1 is provided with a supply port (not shown) for supplying liquid into the support member 1 and a discharge port (not shown) for discharging liquid from the support member 1, and a flow path for supplying and discharging liquid to and from the element substrate H is formed inside.

[0013] FIG. 1(b) is a perspective view showing a liquid ejection head 10 in a form different from the example shown in FIG. 1(a). In the liquid ejection head 10 of this example, eight element substrates H are linearly arranged with respect to one support member 1, and printing with a wide width can be performed at one time. FIG. 1(c) is a perspective view showing a liquid ejection head 10 in a form different from the examples shown in FIGS. 1(a) and 1(b). In the liquid ejection head 10 of this example, four element substrates H are arranged in a staggered manner with respect to one support member 1. Further, the support member 1 of this example has a shape provided with protruding portions protruding outward with respect to each of two sides of a rectangle, rather than a rectangular shape when viewed in the thickness direction of the element substrate H. As in the configuration examples shown in FIGS. 1(a) to 1(c), the number of element substrates H mounted on the liquid ejection head 10 inspected by the circulation inspection device may be any number.

[0014] FIG. 1(d) is a perspective view showing an enlarged element substrate H. The element substrate H includes a plurality of discharge ports 3 for discharging liquid. The discharge ports 3 are arranged in a row extending along the longitudinal direction of the element substrate H, and altogether constitute four discharge port rows. The four discharge port rows composed of the plurality of discharge ports 3 are respectively referred to as discharge port rows 3a, 3b, 3c, and 3d. In the short direction intersecting (orthogonal in this example) with the longitudinal direction of the element substrate H, the four discharge port rows 3a, 3b, 3c, and 3d are provided side by side in this order. In the following description, the longitudinal direction of the element substrate H, that is, the arrangement direction of the discharge ports 3 is the Y direction, the short direction of the element substrate H, that is, the direction in which the discharge port rows 3a, 3b, 3c, and 3d are arranged ( adjacent) direction is the X direction, and the direction orthogonal to the Y direction and the X direction is the Z direction.

[0015] In this example, 128 ejection ports 3 are arranged in each ejection port row 3a to 3d. However, in FIG. 1(d), for the sake of simplification, the illustration of some of the ejection ports 3 is omitted, and a smaller number of ejection ports 3 than the actual number is depicted. Note that the number of rows of the ejection port rows is not limited to 4 rows and can be any number of rows, and the number of ejection ports 3 arranged in one row of the ejection port rows is not limited to 128 and can be any number.

[0016] The element substrate H further includes a pressure chamber communicating with the ejection port 3, a supply port for supplying liquid to the pressure chamber, and a pressure generating element for generating a pressure for ejecting the liquid. These components are provided inside the element substrate H, and these components are not shown in each figure. In the element substrate H, one pressure chamber is provided corresponding to one ejection port 3. Then, due to the pressure generated by the pressure generating element, the liquid in the pressure chamber is ejected from the ejection port 3.

[0017] For the purpose of suppressing the thickening of the liquid due to the evaporation of the liquid (such as water) from the ejection port 3, the liquid in the pressure chamber is circulated between the inside and the outside of the pressure chamber. That is, the liquid ejection head 10 is configured to be able to circulate the liquid in order to control the viscosity of the internal liquid.

[0018] (Circulation inspection device) Next, a circulation inspection device 20 for inspecting the circulation state of the liquid ejection head 10 will be described. FIG. 2 is a perspective view showing the schematic configuration of the circulation inspection device 20. The circulation inspection device 20 includes a workbench 21, two support columns 22 installed on the workbench 21, and a beam 23 extending horizontally between the two support columns 22. The circulation inspection device 20 further includes a camera 25 as a reading means for reading an inspection pattern, and an image processing unit (image processing device), not shown, for evaluating the inspection pattern read by the camera 25. The liquid ejection head 10 to be inspected and the camera 25 facing downward are attached to the beam 23. The liquid ejection head 10 is installed such that the arrangement direction (Y direction) of the ejection ports 3 is parallel to the extending direction of the beam 23. That is, the workbench 21, the support columns 22, and the beam 23 constitute a support portion for supporting the liquid ejection head 10 and the camera 25.

[0019] A Y-stage 26, which can move in the Y direction between the support columns 22, is mounted on the base plate 21, and an X-stage 27, which can move in the X direction, is mounted on top of the Y-stage 26. The recording medium 28 from which liquid is discharged from the liquid discharge head 10 is fixed by suction on the X-stage 27. During the recording operation (printing operation) of the liquid discharge head 10, the recording medium 28 is moved relative to the liquid discharge head 10 in the X direction. The material and shape of the recording medium 28 are not particularly limited, as long as the inspection pattern for circulation inspection is recorded (printed) without problems.

[0020] The X-stage 27 has a liquid receiving tray 29 fixed to it for receiving liquid discharged from the liquid discharge head 10 that does not land on the recording medium 28. The liquid that does not land on the recording medium 28 is, for example, the liquid discharged in the process described later in step (hereinafter referred to as S) 303.

[0021] When inspecting the circulation state of the liquid discharge head 10, the Y stage 26 is moved below the liquid discharge head 10, and an inspection pattern is printed on the recording medium 28 while the drive of the X stage 27 and the discharge of liquid by the liquid discharge head 10 are synchronized. Then, the Y stage 26 and X stage 27 are driven so that the inspection pattern is positioned below the camera 25. The camera 25 then reads the inspection pattern printed on the recording medium 28, and the image processing device, which acts as an image processing unit, evaluates the read inspection pattern to inspect the circulation state.

[0022] The circulating inspection device 20 includes a drive control unit capable of performing recording operations (printing operations) by the liquid discharge head 10 and image reading operations by the camera 25, and a unit capable of performing processing and evaluation of inspection patterns. The device comprises an image processing unit (image processing device) and a control unit (not shown) which includes an image processing unit. The control unit can be composed of, for example, a processor, memory, storage, etc. In this case, the functions of the control unit are realized by the processor executing a program stored in the memory or storage. Furthermore, the image processing unit for processing the inspection pattern does not have to be incorporated as part of the control unit. The circulating inspection device 20 may also be configured as an independent device, or it may be incorporated as part of the configuration or function of a liquid dispensing device such as a printer.

[0023] The circulation inspection system, which inspects the circulation state of the liquid discharge head 10 using the circulation inspection device 20 described above, will now be explained in several embodiments.

[0024] <First Embodiment> A first embodiment of the inspection system for checking the state of circulation will be described with reference to Figures 3 to 7.

[0025] (Liquid circulation test) First, using the liquid discharge head 10 with the configuration shown in Figure 1(a) as an example, the method for inspecting the circulation state of the liquid in the pressure chamber according to this embodiment will be explained. Figure 3 is a flowchart of the method for inspecting the circulation state of the liquid (inspection flow) according to this embodiment.

[0026] First, in S301, the liquid discharge head 10 to be inspected is mounted on the circulation inspection device 20, and the recording medium 28 is mounted on the X-stage 27.

[0027] Next, in S302, the stages (X stage 27 and Y stage 26) are moved to predetermined initial positions. The initial position is the position where the liquid receiving tray 29, which is fixed to the X stage 27, is positioned directly below the liquid discharge head 10.

[0028] Next, in S303, continuous discharge of droplets from all discharge ports 3 is initiated, and the continuous liquid discharge process is executed. At this time, the droplets discharged from each discharge port 3 are collected in the liquid receiving tray 29 and do not land on the recording medium 28.

[0029] By executing the process in S303, all discharge ports 3 can be brought into a state where they can discharge liquid normally. This is because, even if a discharge port 3 is experiencing discharge problems due to poor liquid circulation, by continuously discharging liquid from the discharge port 3, the viscous liquid inside the discharge port is discharged into the liquid receiving tray 29, and fresh liquid is refilled into the discharge port 3. In other words, by executing S303, only liquid with a viscosity sufficient for normal discharge will be present in the discharge port 3. To put it another way, S303 is a viscosity control process (viscosity adjustment process) that controls (adjusts) the viscosity of the liquid so that low-viscosity liquid is present in the discharge port 3. In other words, the circulation inspection device 20 has a viscosity control means for controlling the viscosity of the liquid inside the liquid discharge head 10. In this embodiment, the control unit that controls the operation of the liquid discharge head 10 functions as the viscosity control means.

[0030] In S303, liquid was continuously discharged from all discharge ports 3 in order to bring the discharge ports into a state where they could discharge normally, but this embodiment is not limited to this. That is, any process that can bring the discharge ports 3 into a state where they can discharge normally can be used as an alternative to the continuous discharge process in S303. For example, a cap member (not shown) may be attached to the element substrate H to draw air into the element substrate H and release the liquid in the discharge ports 3 to the outside, thereby lowering the viscosity of the liquid in the discharge ports 3 and bringing the discharge ports into a state where they can discharge normally.

[0031] After a predetermined time has elapsed since the start of liquid discharge, in S304, the liquid discharge is stopped, and a period of discharge pause (discharge pause process) begins. During this period (process), all discharge ports 3 During the pause period when no dispensing occurs, the volatile components in the liquid evaporate, causing the liquid in the discharge port to become thicker. In other words, by performing S304, the viscosity of the liquid in the discharge port increases. Therefore, S304 can be described as both a dispensing pause process and a viscosity control process that controls the viscosity of the liquid.

[0032] In this embodiment, the pause time is set to 2 minutes, but this may be changed as appropriate depending on the diameter of the discharge port 3 and the components of the liquid. In addition, to shorten the pause time, air may be blown towards the discharge port 3 using an air blow nozzle to promote the evaporation of volatile components in the liquid. In other words, the circulation inspection device 20 has a discharge pause means for pausing the discharge from the liquid discharge head 10. In this embodiment, the control unit that controls the operation of the liquid discharge head 10 functions as a viscosity control means capable of executing a discharge pause operation to suspend discharge.

[0033] After the pause period has elapsed, in S305, a circulation process is started to circulate the liquid in the pressure chamber connected to the discharge port 3. At this time, if the liquid circulation function is normal, even if the discharge of liquid from the discharge port 3 is paused, the liquid in the pressure chamber connected to the discharge port 3 is circulated with the outside of the pressure chamber, so the degree of viscosity increase of the liquid inside the discharge port 3 is minimal.

[0034] In this embodiment, the circulation process is performed after the discharge pause process, but this method is not limited to this. For example, the viscosity control operation in S303 (viscosity control process) and the discharge pause operation in S304 (discharge pause process) may be performed while the liquid is circulating. As the circulation means for circulating the liquid in the circulation process, for example, a pump can be used. Furthermore, during the circulation operation, the operation of the circulation means is controlled by the control unit.

[0035] The circulation means for circulating the liquid in the pressure chamber may be provided, for example, independently of the liquid discharge head 10 in the circulation inspection device 20, or it may be provided directly on the liquid discharge head 10. However, in order to inspect the liquid discharge head 10 used in a liquid discharge device equipped with an independent circulation means, it is necessary to provide the circulation means in the circulation inspection device 20. When the circulation means is provided in the circulation inspection device 20, it is preferable that it is the same as the circulation means provided in the liquid discharge device in which the liquid discharge head 10 is used. In this description, even if the circulation means is mounted on the liquid discharge head 10, the circulation inspection device 20 will be described as being equipped with a circulation means.

[0036] Next, in S306, the inspection pattern is printed on the recording medium 28. During the inspection pattern printing process, the Y stage 26 and X stage 27 are driven so that the recording medium 28 moves below the liquid discharge head 10. The inspection pattern is printed by discharging liquid from the same discharge port 3 toward the recording medium 28 multiple times while the recording medium 28 moves relative to the liquid discharge head 10 in the X direction. Details of the inspection pattern will be described later.

[0037] Next, in S307, the inspection pattern printed on the recording medium 28 is read. In the inspection pattern reading process, the Y stage 26 and X stage 27 are driven, and the printed inspection pattern is read by the camera 25. Then, in S308, the read inspection pattern is evaluated. In this embodiment, the evaluation result of the inspection pattern is either normal or abnormal.

[0038] In S309, the circulation of the liquid in the pressure chamber is stopped, and then the liquid discharge head 10 is removed from the circulation inspection device 20.

[0039] In S310, the pattern evaluation result from S308 is displayed as normal or abnormal, and the circulation test of the liquid in the pressure chamber is completed. The display of the evaluation result is, for example, by a circulation test device. A monitor may be provided at unit 20, or the control unit may display the results on another terminal. Furthermore, the means of notifying the user of the evaluation results are not limited to monitors, etc. For example, the user may be notified by sound if an abnormality has occurred.

[0040] (Test pattern) Next, the inspection pattern printed in S306 and the inspection pattern evaluation method in S308 will be explained using Figures 4(a) to 7(b). To explain the inspection pattern, first, the nozzle row and impact dot diameter of the liquid discharge head 10 inspected in this embodiment will be described.

[0041] The discharge port array consists of 128 discharge ports 3 arranged at a resolution of 150 dpi. Therefore, the distance between the centers of adjacent discharge ports 3 in the Y direction is approximately 169 micrometers. The diameter of the dots that land on the recording medium 28 may vary depending on the liquid material and the material of the recording medium, but in this embodiment it is approximately 50 micrometers. Therefore, even when liquid is discharged simultaneously from adjacent discharge ports 3, the two landed droplets (landed dots) will not overlap.

[0042] Figures 4(a) and 4(b) are explanatory diagrams of the inspection pattern according to the first embodiment. Figure 4(a) is a schematic diagram of the entire inspection pattern printed using all the ejection ports 3 of the element substrate H. The inspection pattern is a long straight line in the direction that intersects the direction in which the ejection port row 3a extends (Y direction, first direction), that is, in the transport direction of the recording medium (X direction, second direction). Hereafter, such a straight inspection pattern will be referred to as a vertical line. Figure 4(a) shows 128 vertical lines A1 to A128 printed by the ejection port row 3a (each ejection port 3). Similarly, Figure 4(a) shows 128 vertical lines B1 to B128 printed by the ejection port row 3b, 128 vertical lines C1 to C128 printed by the ejection port row 3c, and 128 vertical lines D1 to D128 printed by the ejection port row 3d.

[0043] Vertical line A1 is a vertical line printed by the discharge port 3 located at one end in the Y direction (the starting point of the arrow indicating the Y direction) among the discharge port 3 that make up the discharge port row 3a. Vertical line A128 is a vertical line printed by the discharge port 3 located at the other end in the Y direction (the ending point of the arrow indicating the Y direction) among the discharge port 3 that make up the discharge port row 3a. The inspection pattern (vertical line) is an independent pattern for each discharge port, and is not a pattern formed in a grid shape where vertical and horizontal lines intersect, for example.

[0044] Next, the details of the inspection pattern (vertical lines) will be explained. Figure 4(b) is a schematic diagram of the inspection pattern (vertical lines) printed by one discharge port 3. The inspection pattern shown in Figure 4(b) is an ideal pattern, and in the printing process of S306, the circulating inspection device 20 is driven to print the inspection pattern shown in Figure 4(b). Then, in the printing process of S306, vertical lines A1 to A128 are printed by driving the discharge port row 3a. All discharge ports 3 of the liquid discharge head 10 are driven to print the pattern shown in Figure 4(b).

[0045] The vertical lines are formed by dispensing 10 times consecutively from the same dispensing port 3. More specifically, the vertical lines are formed when 10 droplets (liquid) that land on the recording medium 28 with each dispensing are connected so that they overlap in the X direction. The fine shape of the vertical lines can vary depending on the transport speed of the recording medium, the dispensing time interval, the amount of liquid dispensed (diameter of the flying droplets), the viscosity of the liquid, and the material of the recording medium. To ensure that adjacent droplets are reliably connected, it is preferable to set the overlap length to be about one-quarter to one-half of the diameter of the droplets, preferably about one-third of the diameter.

[0046] To ensure that one-third of adjacent projectile droplets overlap, the following discharge time interval T is required. This can be achieved by discharging the liquid. If M is the seepage rate, which is determined by the viscosity of the liquid used and the material of the recording medium, V is the transport speed of the recording medium 28, and P is the discharge amount, then the discharge time interval T for continuous discharge is calculated by the following equation 1.

number

[0047] In this embodiment, the discharge volume P = 2 picoliters, the transport speed V of the recording medium 28 = 0.7 meters per second, and the bleeding rate M = 3, so the discharge time interval T = approximately 45 microseconds is used to print vertical lines. To ensure that half the diameter of adjacent droplets overlaps, the discharge time interval T should be approximately 34 microseconds, and to ensure that one-quarter overlaps, the discharge time interval T should be approximately 50 microseconds. Therefore, in this embodiment, the desired vertical lines can be printed by setting the discharge time interval between 34 and 50 microseconds.

[0048] Furthermore, one-third of adjacent droplets overlap, and the length L of the vertical line formed by 10 droplets is calculated using the following equation 2.

number

[0049] Next, the evaluation method for the inspection pattern of S308 will be described. The evaluation of the inspection pattern is performed by image processing of the data obtained by capturing the pattern as an image. Figure 5 is a flowchart of the evaluation flow of the inspection pattern according to the first embodiment. Figures 6(a) to (c) are schematic diagrams of the image processing procedure according to the flowchart of Figure 5, illustrating an example of an inspection pattern printed by the liquid discharged from the discharge port row 3a. The processing of the inspection pattern printed from the discharge port row 3a will be described below, but the processing procedure is the same for the other discharge port rows 3b to 3d. In this embodiment, the image processing unit processes the image of the inspection pattern and functions as a circulation inspection means to inspect the circulation state of the liquid discharge head, but the configuration is not limited to this, and other control units may take on this role.

[0050] First, in S501, the image processing unit sets the area to be image processed from all inspection patterns. In the evaluation of the output row 3a, the inspection patterns to be image processed are the vertical lines A1 to A128. Therefore, the image processing area is an area that completely includes all of the vertical lines A1 to A128 (slightly wider than the entirety of the vertical lines A1 to A128). In Figure 4(a), the image processing area 51 is shown by a dashed line. The image processing area 51 is a rectangular area that encloses all 128 vertical lines A1 to A128.

[0051] Figure 6(a) is a magnified view of an example of the state within the image processing area 51. Reference numerals 61 to 63 in the figure indicate printed vertical lines, reference numeral 64 indicates a single (one-drop) impact dot, and reference numeral 65 indicates foreign matter adhering to the surface of the recording medium. In addition to impact dots, the recording medium may also have foreign matter adhering to it, such as parts of the material constituting the recording medium (for example, fibers if the recording medium is paper) or small dust particles. The details of the presence of a single impact dot 64 will be described later.

[0052] Next, in S502, the image processing unit performs an extraction process to extract clusters of impact dots (dot clusters) within the image processing area 51. As mentioned above, vertical lines A1 to A128 exist within the image processing area 51. These vertical lines A1 to A128 are formed by overlapping impact dots forming clusters, so first all dot clusters are extracted. Figure 6(b) is a schematic diagram of the state after dot clusters have been extracted from the state in Figure 6(a). The symbols 71 to 75 in the figure represent the locations extracted as dot clusters. As shown in Figure 6(b), in addition to the vertical lines 61 to 63, individual impact dots 64 and foreign objects 65 may also be extracted as dot clusters. Therefore, the number of dot clusters extracted in S502 may be greater than the number of vertical lines (128 in this example).

[0053] Next, in S503, the image processing unit performs a sorting process (exclusion process) to select the dot clusters extracted in S502. In S502, individual impact dots 64 and foreign objects 65, which are not vertical lines, are also extracted as dot clusters, so in S503, a process is performed to exclude these dot clusters from the inspection target. Specifically, the image processing unit calculates the area of ​​each dot cluster extracted in S502 and excludes dot clusters that have not reached a predetermined area. In this embodiment, dot clusters that have not reached half (50%) of the expected (ideal) dot cluster area are excluded.

[0054] Figure 6(c) shows the state after processing S503 is completed, compared to Figure 6(b). Dot clusters 74 and 75, which were recognized as dot clusters in processing S502 (the state in Figure 6(b)), are determined to be less than a predetermined area in S503 and are excluded from the dot clusters. Then, only dot clusters 71 to 73 remain in Figure 6(c).

[0055] In this embodiment, the decision of whether or not to inspect a dot cluster was based on its area, but the configuration is not limited to this. For example, the length of the longer side may be used instead of the area of ​​the dot cluster.

[0056] Next, in S504, the image processing unit determines whether the number of dot clusters in the image processing area 51 matches the number of ejector ports 3. When the processing in S503 is completed, all of the dot clusters recognized are vertical lines (inspection patterns). Therefore, if the inspection patterns are printed correctly, there will be 128 dot clusters in the image processing area 51, which is the same number as the number of ejector ports 3 in the ejector port row. If the number of dot clusters is less than 128 (NO in S504), the image processing unit determines that there is an ejector port with ejection defects and terminates the evaluation flow abnormally. Conversely, if the number of dot clusters exceeds 128 (NO in S504), the image processing unit determines that some kind of malfunction has occurred and terminates the evaluation flow abnormally. In the case of abnormal termination, the result output processing in S310 notifies the user that an abnormal termination has occurred, specifically that there is an ejector port with ejection defects. Furthermore, if the number of dot clusters equals the number of discharge ports (=128) (YES in S504), proceed to S505 and continue the evaluation flow.

[0057] Next, in S505, the image processing unit obtains the length of each vertical line within the image processing area 51. The method for obtaining the length of the vertical lines will be explained with reference to an example of an inspection pattern shown in Figures 7(a) and 7(b). Figures 7(a) and 7(b) are explanatory diagrams of the method for obtaining the length of the inspection pattern, and show an example of an inspection pattern different from the example shown in Figures 6(a) to 6(c).

[0058] Figure 7(a) is an example of a magnified view of a portion of the image processing area 51. Figure 7(a) shows three vertical lines 81-83 and a liquid droplet 84 from among the 128 printed vertical lines. All three vertical lines 81-83 are in a state where liquid has landed on the recording medium 28 after being ejected 10 times at time intervals equal to equation 1.

[0059] The vertical lines 81 are an example of an inspection pattern formed when liquid was discharged from the discharge port 3 in all 10 discharge operations and all 10 drops landed on the recording medium 28. The length L81 of the vertical lines 81 is approximately the same as the value calculated by equation 2. Since there is some variation in the actual discharge volume and bleeding rate, the actual length L is expected to differ from the calculated value by up to 5 percent.

[0060] The vertical lines 82 represent an example of an inspection pattern formed by the 6 drops from the 5th to the 10th drop, where the 1st to 4th drops did not land on the recording medium during the 10 ejection operations. Therefore, the length L82 of the vertical lines 82 is less than the value calculated by equation 2, and in this embodiment, it is determined to be a defective print.

[0061] If an inspection pattern like vertical lines 82 is formed, it can be said that the first 1-4 drops did not land, and therefore the first four dispensing operations were not performed correctly. However, liquid was dispensed from the dispensing port 3 from the 5th drop onward. Therefore, it can be concluded that there was a problem with liquid circulation, and the thickened liquid remained in the dispensing port 3, but as the dispensing operation was repeated, the thickened liquid moved and normal dispensing became possible. If all 10 drops did not land, it could be concluded that the problem was due to factors other than liquid circulation, such as a blockage in the dispensing port. Therefore, it is determined that there was a problem with liquid circulation in the dispensing port 3 used to print the vertical lines 82.

[0062] As in this example, if there is a problem with liquid circulation, even if normal dispensing is not possible at the beginning of dispensing, it is often possible to achieve normal dispensing by repeating the dispensing process. The number of dispensing cycles required to achieve normal dispensing varies depending on the viscosity of the liquid and the diameter of the dispensing port, but in the configuration of this embodiment, it is determined whether the problem is a liquid circulation problem or a problem other than liquid circulation by performing 10 dispensing operations.

[0063] The vertical line 83 indicates that the 2nd to 10th drops out of the 10 dispensed drops form the vertical line. Since its length L83 is less than the value calculated by formula 2, it is judged as a defective print.

[0064] The droplet 84 is a droplet that was ejected and landed during the initial ejection operation when printing the vertical ruled lines 83. If the ejection speed of the droplets is slower than normal due to a faulty ejection condition, and the ejection direction is also slightly off, some droplets, like droplet 84, may not overlap with other droplets and may not form the vertical ruled lines 83. Such abnormal ejection may occur if the liquid circulation is insufficient, but normal ejection will be possible after repeating the ejection operation.

[0065] Both vertical lines 82 and 83 (and droplets 84) are formed due to poor circulation of the liquid, but the degree of the defect in vertical line 83 is less severe than that of vertical line 82.

[0066] Finally, in S506, the image processing unit determines whether the lengths of all vertical lines A1 to A128 are within a predetermined range. Specifically, it determines whether the lengths of all 128 vertical lines A1 to A128, the same number as the 3 discharge ports in the discharge port row 3a, are within the range of 95-105% of the length calculated by equation 2. If all 128 lines are of the predetermined length, the pattern evaluation flow completes normally. However, if even one vertical line is not of the predetermined length, the process terminates abnormally. In the case of normal termination, the result output process in S310 informs the user that the circulation status is normal, i.e., that circulation is functioning normally. On the other hand, in the case of abnormal termination, the result output process in S310 informs the user that there is a discharge port with a discharge defect. At this time, the degree of the defect and the suspected cause of the defect (such as poor circulation or foreign matter blockage) may also be informed to the user. In this way, the image processing unit, based on the inspection pattern, evaluates the liquid discharge head 1 It functions as a circulation inspection method to check the state of circulation of 0.

[0067] In this embodiment, the length of the vertical lines is determined to be within ±5% of the theoretical value, but the configuration is not limited to this. The setting range may be changed depending on the type of liquid or recording medium and the discharge conditions. Alternatively, the configuration may be such that the determination is made based on whether or not the length of the vertical lines is equal to or greater than a predetermined threshold, without setting an upper limit for the predetermined length.

[0068] In the above explanation, we used outlet row 3a as an example to describe the method for inspecting (evaluating) the liquid circulation function, but the other outlet rows 3b to 3d can be inspected (evaluated) in the same way.

[0069] The liquid circulation function inspection method (circulation inspection system) of the liquid discharge head 10 described above is summarized below. In the liquid circulation function inspection according to this embodiment, liquid droplets are first discharged continuously from all discharge ports 3, and liquid circulation is started after discharge stops. After this state is maintained for a predetermined time, vertical lines are printed as an inspection pattern for each nozzle row, and each vertical line is evaluated. If the liquid circulation is normal, the length of the vertical lines will be a predetermined length, but if there is a circulation problem, the length of the vertical lines will be less than (or more than) the predetermined length. Based on the differences in the formation of such inspection patterns, the state (appearance) of liquid circulation is inspected.

[0070] According to the configuration of this embodiment, each discharge port in the discharge port row continuously discharges liquid to form (print) an independent inspection pattern (vertical ruled line). Therefore, even if the arrangement density of discharge ports in the discharge port row is low, or if the discharged droplets are small and the droplets from adjacent discharge ports do not overlap, making it impossible to print a continuous straight line parallel to the discharge port row, an inspection pattern can still be printed by continuously discharging from the same discharge port. By evaluating the inspection pattern, the state of liquid circulation can be appropriately inspected without misjudging.

[0071] (Second Embodiment) Next, a second embodiment of the circulation inspection system for inspecting the circulation state will be described. The second embodiment differs from the first embodiment in the arrangement of the discharge port 3 of the liquid discharge head 10. Hereinafter, only the differences between the configuration of the second embodiment and the configuration of the first embodiment will be described. Components in the second embodiment that are the same as those in the first embodiment are denoted by the same reference numerals and their descriptions are omitted.

[0072] The liquid discharge head 10 to be inspected in the second embodiment has the same configuration as in the first embodiment, with one element substrate H arranged on one support member 1 as shown in Figure 1(a). However, the liquid discharge head 10 to be inspected in the second embodiment differs from that of the first embodiment in the number and arrangement density of the discharge ports 3.

[0073] In the second embodiment, the arrangement density of the discharge ports 3 is 600 dpi, with 512 discharge ports 3 arranged in one row of discharge ports. Therefore, the distance between the centers of adjacent discharge ports is approximately 42 micrometers. The diameter of the projectile dot is approximately 50 micrometers, similar to the first embodiment. The inspection flow of this embodiment is generally the same as the flows in Figures 3 and 5 described in the first embodiment, but there are differences due to the difference in nozzle arrangement density, which will be explained below.

[0074] In the first embodiment, the inspection pattern was formed by discharging liquid from all the outlets 3 within a single row of outlets, as shown in Figure 4(a). However, in the second embodiment, the density of the outlets 3 is higher compared to the first embodiment. Therefore, if the same discharging operation as in the first embodiment is performed to print the inspection pattern in the second embodiment, the impact dots of adjacent outlets 3 will overlap. As a result, the inspection pattern will be printed as a solid block without gaps. Therefore, it is not possible to inspect each discharge port. In the second embodiment, the discharge timing of the discharge port 3 is controlled so that the inspection pattern is formed with a shift in the transport direction (X direction) of the recording medium 28.

[0075] Figure 8 is an explanatory diagram of the inspection pattern according to the second embodiment. Figure 8 shows the inspection pattern (vertical lines A1 to A512) printed using the ejection port 3 of the ejection port row 3a of the element substrate H. Although not shown, below the vertical lines A1 to A512 in Figure 8 (upstream side in the transport direction of the recording medium 28), the inspection patterns printed using ejection port rows 3b, 3c, and 3d follow. The inspection pattern and the like will be explained below using ejection port row 3a as an example, but the same applies to the other ejection port rows 3b to 3d.

[0076] The inspection pattern formed by discharging liquid from each outlet 3 is a vertical grid line, similar to that in the first embodiment. In the second embodiment, instead of discharging from all outlets 3 within the same row of outlets at the same time, all outlets 3 are divided into four groups: the first group, the second group, the third group, and the fourth group, and discharging is performed at different times for each group. In other words, in the first embodiment, all inspection patterns in the row of outlets 3a were in the same position in the X direction and lined up in a row in the Y direction, but in the second embodiment, the inspection patterns in the row of outlets 3a are printed with a shift in the X direction.

[0077] The first group includes discharge ports 3 every four ports starting from the discharge port 3 at one end of the discharge port row 3a. That is, the first group includes the 1+4n (n=0, 1, ..., 127)th discharge port 3 from one end of the discharge port row 3a. Similarly, group 2 includes discharge ports 3 every four ports starting from the second discharge port 3 from one end of the discharge port row 3a, i.e., the 2+4n (n=0, 1, ..., 127)th discharge port 3 from one end of the discharge port row 3a. The third group includes discharge ports 3 every four ports starting from the third discharge port 3 from one end of the discharge port row 3a, i.e., the 3+4n (n=0, 1, ..., 127)th discharge port 3 from one end of the discharge port row 3a. The fourth group includes discharge ports 3 every four ports starting from the fourth discharge port 3 from one end of the discharge port row 3a, i.e., the 4+4n (n=0, 1, ..., 127)th discharge port 3 from one end of the discharge port row 3a. By staggering the discharge timing for each group in this way, it is possible to print an inspection pattern in which the impact dots from adjacent discharge ports 3 do not overlap.

[0078] The time difference between groups in terms of discharge timing is set to 14 times the discharge time interval T calculated by formula 1. In other words, the discharge timing for group 2 is 14T after the discharge timing for group 1. The discharge timing for group 3 is 28T after the discharge timing for group 1. The discharge timing for group 4 is 42T after the discharge timing for group 1. As a result, the gap between groups (for example, the gap in the X direction between vertical lines A1 and A2) is the length of four droplets that make up the vertical lines.

[0079] Furthermore, the number of groups is not limited to 4; it may be 8 or 16. Also, the number of groups can be reduced depending on the arrangement density of the discharge ports 3. Moreover, instead of forming the inspection pattern in the order of the first group, second group, third group, and fourth group, the inspection pattern may be formed in the order of the first group, third group, second group, and fourth group, for example.

[0080] In the second embodiment, the evaluation flow of the inspection pattern is generally the same as that of the first embodiment shown in Figure 5. However, in setting the image processing area in S501, it is necessary to set an image processing area 52 that is wider than the image processing area 51 set in the first embodiment. This is because the image processing area 52 is designed so that all impact dots (vertical lines A1 to A512) that are ejected from all the ejection ports 3 of the ejection port row 3a and land on the surface are subject to image processing.

[0081] The processing from S502 onward is carried out for each group in the same manner as in the first embodiment. In S506, the evaluation flow completes normally if the length of all (512) vertical lines is within the predetermined length (within the predetermined range), and the evaluation flow terminates abnormally if even one vertical line is not of the predetermined length.

[0082] Based on the above, in the case of a configuration where the arrangement density of the discharge ports 3 is high, as in the second embodiment, and discharging liquid simultaneously from all discharge ports in the row of discharge ports may result in solid printing, it is preferable to group the discharge ports and stagger the timing for each group. This ensures that the inspection patterns (vertical lines) printed (formed) by different discharge ports do not overlap, and independent inspection patterns corresponding to each discharge port are printed (formed). Therefore, the state of liquid circulation can be appropriately inspected at each discharge port.

[0083] (Third embodiment) Next, a third embodiment of the circulation inspection system for inspecting the circulation state will be described. The third embodiment differs from the first embodiment in that the evaluation flow of the inspection pattern includes a twist inspection step for inspecting the amount of twist. Below, only the differences in the configuration of the third embodiment from the configurations of the first and second embodiments will be described. Components in the configuration of the second embodiment that are the same as those in the configuration of the first or second embodiment will be denoted by the same reference numerals and their description will be omitted.

[0084] The liquid dispensing head 10 to be inspected in the third embodiment is the same as in the second embodiment. That is, it has the configuration shown in Figure 1(a), with an array density of 600 dpi for the dispensing ports 3, and 512 dispensing ports 3 arranged in one row of dispensing ports. The inspection flow in the third embodiment is the same as the flow shown in Figure 3 described in the first embodiment, but the evaluation flow of the inspection pattern has several processes added to the flow shown in Figure 5. Therefore, the additional processes in the evaluation flow of the inspection pattern will be described below.

[0085] Figure 9 is a flowchart showing the evaluation flow of the inspection pattern according to the third embodiment. In the third embodiment, following the process of inspecting the state of liquid circulation described in the first embodiment, a process of inspecting the amount of distortion at the point of impact is added. Since S501 to S506 are the same as in the first embodiment, their explanation is omitted, and the explanation will be given from S507 onwards. Also, since the inspection method for the amount of distortion is the same for each discharge port row 3a to 3d, the following explanation will use discharge port row 3a as an example, and the explanation for the other discharge port rows 3b to 3d will be omitted.

[0086] The process up to S506 determines whether the length of all 512 inspection patterns (vertical lines) shown in Figure 8 is within a predetermined length (within a predetermined range). In the third embodiment, if it is determined in S506 that the length of all inspection patterns is within the predetermined length, the evaluation flow continues and proceeds to the twist inspection process from S507 onwards.

[0087] In S507, the image processing unit calculates and obtains the centroid (vertical line centroid) of each vertical line A1 to A512 by image processing. Figures 10(a) to (d) are explanatory diagrams of the grid coordinate inspection method used for inspecting the amount of distortion according to the third embodiment. Figures 10(a) to (d) show the centroids g1 to g512, which indicate the centroid positions of each vertical line A1 to A512. The centroid is located approximately at the center in the X and Y directions of the corresponding vertical line.

[0088] Figure 10(a) is a schematic diagram showing the state after the vertical line centroid acquisition process of S507 has been executed. The example shown in Figure 10(a) is an example in which vertical lines A1 to A512 are printed in the ideal position. In this case, four columns of centroids are formed, aligned in the Y direction. These columns are offset from each other in the Y direction. From a different perspective, 128 columns are formed, extending diagonally in the X direction, composed of the four centroids.

[0089] Next, in S508, the image processing unit calculates the centroid coordinates of the centroids g1 to g512 of the vertical lines and the grid coordinates indicating the ideal positions of the centroids g1 to g512. The vertical lines A1 to A512 that are actually printed are not all printed in ideal positions. This is because the printing position (the position where the liquid lands on the recording medium) varies to some extent due to various factors such as the direction of liquid discharge and the accuracy of the formation of the discharge port 3. Therefore, in the third embodiment, in addition to checking the state of liquid circulation, the amount of distortion, which represents the variation in printing position, is also checked. The grid coordinates calculated in S508 are used as the basis for calculating the amount of distortion, and the amount of distortion corresponds to the amount of deviation between the centroid coordinates and the grid coordinates.

[0090] The method for calculating grid coordinates will be explained in detail. First, the centroids g1 to g512 are grouped in groups of four from one end in the Y direction, i.e., g1 to g4, g5 to g8, ..., g509 to g512. This grouping of centroids g1 to g512 into groups of four centroids aligned linearly in a direction intersecting the X and Y directions is called the first grouping. Figure 10(b) is a schematic diagram showing the state after the first grouping has been performed. Then, each group divided by the first grouping is called a diagonal group m0 to m127. Each diagonal group m0 to m127 is composed of four centroids aligned linearly in the lower right direction in Figure 10(b).

[0091] The diagonal group m0 located on the far left (one end in the Y direction) of Figure 10(b) includes centroids g1 to g4. The diagonal group m1 adjacent to the right of diagonal group m0 includes centroids g5 to g8. The diagonal group m127 located on the far right (the other end in the Y direction) of Figure 10(b) includes centroids g509 to g512. Hereafter, the numerical values ​​0 to 127 assigned to the diagonal group symbols m0 to m127 may be referred to as the diagonal group numbers.

[0092] Next, the centers of gravity g1 to g512 are grouped into four groups according to their position in the X direction. This grouping, which divides the centers of gravity g1 to g512 into 128 groups aligned linearly in the Y direction, is called the second grouping. Figure 10(c) is a schematic diagram showing the state after the second grouping has been performed. The groups divided by the first grouping are then designated as horizontal groups n0 to n3. Hereafter, the numerical values ​​0 to 3 assigned to the horizontal group symbols n0 to n3 may also be referred to as horizontal group numbers.

[0093] Next, the coordinates of the centroids g1 to g512 are calculated. For the sake of explanation, in Figures 10(a) to (c), the centroids g1 to g512 of the vertical lines are represented as centroid e(m,n). m is the number of the diagonal group mentioned above, and n is the number of the horizontal group. Figure 10(d) shows the centroids g1 to g127 expressed in the form e(m,n). For example, centroid g1 is represented as e(0,0) because its diagonal group number is 0 and its horizontal group number is 0, and centroid g512 is represented as e(127,3) because its diagonal group number is 127 and its horizontal group number is 3.

[0094] Figure 10(d) shows the grid 40 formed by connecting the centroids of adjacent vertical lines A1 to A512 when they are formed in their ideal positions. In other words, the intersections of grid 40 (grid intersections) indicate the ideal positions of the centroids. The reference position of grid 40 is the grid intersection closest to the centroid e(0,0) of vertical line A1, and this grid intersection is denoted as k(0,0). The X coordinate Xk(0,0) and Y coordinate Yk(0,0) of the grid intersection k(0,0) can be calculated using the following equations 3 and 4.

number

number

[0095] Then, if we let the X coordinate of the grid intersection k(m,n) of diagonal group number m and horizontal group number n be Xk(m,n) and the Y coordinate be Yk(m,n), the X and Y coordinates of each grid intersection can be calculated using the following equations 5 and 6.

number

number

[0096] Following the above procedure, in S508, the image processing unit calculates and obtains the centroid coordinates of the centroids g1 to g512 of each vertical grid line A1 to A512, and the intersection coordinates of the grid 40 that represent the ideal positions of the centroids g1 to g512.

[0097] Next, in S509, the image processing unit calculates the amount of distortion of each vertical line centroid from the coordinates of each intersection point of the grid 40 and the coordinates of each vertical line centroid. Figure 11 is an explanatory diagram of the method for calculating the amount of distortion, and is a schematic diagram showing a part of the grid 40 and an enlarged view of the vertical line centroids.

[0098] The amount of distortion of the centroid of a vertical line is expressed by the X-direction distance and Y-direction distance between the centroid e(m,n) of a vertical line having the same diagonal group number m and horizontal group number n and the grid intersection k(m,n). For example, the amount of distortion of the centroid e(1,2) of vertical line A7 can be found by subtracting the coordinates of the grid intersection k(1,2) from the coordinates of the centroid e(1,2). Specifically, if the X-coordinate of the centroid e(m,n) is Xe(m,n) and the Y-coordinate is Ye(m,n), then the amount of distortion of the centroid e(1,2) is calculated as |Xe(1,2)-Xk(1,2)| and |Ye(1,2)-Yk(1,2)|.

[0099] Finally, in S510, the image processing unit determines whether the amount of distortion at the centroid of each vertical line is below a predetermined amount. The predetermined amount is a quantity (threshold) related to print quality, and in this embodiment, it is set to 40 micrometers. In the third embodiment, if both the amount of distortion (shift) in the X direction and the amount of distortion (shift) in the Y direction are below the predetermined amount, it is determined that there is no problem. Therefore, the evaluation flow terminates normally if the amount of distortion in the X and Y directions of the centroids g1 to g512 of all vertical lines A1 to A512 is below the predetermined amount. On the other hand, if the amount of distortion in one or more lines exceeds the predetermined amount, the evaluation flow terminates abnormally.

[0100] Furthermore, in the event of an abnormal termination, the system may be configured to notify the user, for example, which outlet 3 had a deviation in the centroid of the vertical lines formed on it that exceeded a predetermined value. Alternatively, the numerical values ​​for each twist amount may be sent together to a separate external terminal. Furthermore, instead of calculating the twist amounts for the X and Y directions separately, the shortest distance between the centroid e(m,n) and the grid intersection k(m,n) may be calculated as the twist amount and used for the determination.

[0101] Thus, according to the configuration of the third embodiment, the amount of distortion can be inspected using an inspection pattern printed to check the state of liquid circulation. This allows for simultaneous inspection of the circulation state and the amount of distortion, even when it is necessary to inspect the amount of distortion, without printing a separate pattern for distortion inspection. Therefore, this leads to a reduction in ink consumption and a shortening of inspection time.

[0102] This embodiment includes the following configuration. (Composition 1) A liquid discharge head having a row of discharge ports arranged in a first direction for discharging liquid, and a pressure chamber communicating with the discharge ports and having a pressure generating element for generating pressure to discharge liquid from the discharge ports, A circulation means for circulating the liquid inside the pressure chamber between the outside of the pressure chamber and the outside of the pressure chamber, A drive control unit that controls the operation of the liquid discharge head and the circulation means, the drive control unit capable of performing a discharge pause operation to pause the discharge of liquid from the discharge port, a circulation operation to circulate the liquid in the pressure chamber communicating with the discharge port between the outside of the pressure chamber and the outside of the pressure chamber, and a printing operation to discharge liquid multiple times from the same discharge port to print a long inspection pattern on a recording medium in a second direction intersecting the first direction, A circulation inspection means for inspecting the circulation state of the liquid discharge head based on the length of the inspection pattern in the second direction, A liquid dispensing device characterized by comprising the following features. (Configuration 2) The inspection pattern is formed when a plurality of droplets formed by the liquid discharged from the discharge port hitting the recording medium overlap each other in the second direction. A liquid dispensing device as described in Configuration 1. (Composition 3) The inspection pattern is formed such that one-quarter to one-half of the diameter of the impact droplet overlaps with an adjacent impact droplet. The liquid dispensing device described in Configuration 2. (Composition 4) If the length of the second direction of the inspection pattern is shorter than a predetermined threshold, the user is notified that the circulation is poor. A liquid dispensing device according to any one of configurations 1 to 3. (Composition 5) The circulation inspection means inspects the circulation state of the liquid discharge head based on the length of the inspection pattern in the second direction, as well as the number of inspection patterns printed on the recording medium. A liquid dispensing device according to any one of configurations 1 to 4. (Composition 6) The drive control unit performs a viscosity control operation to control the viscosity of the liquid inside the discharge port before the discharge pause operation. A liquid dispensing device according to any one of configurations 1 to 5. (Composition 7) In the aforementioned printing operation, liquid is discharged from all the discharge ports constituting the discharge port row at approximately the same timing. A liquid dispensing device according to any one of the configurations 1 to 6. (Composition 8) In the printing operation, liquid is discharged at different timings from two adjacent discharge ports in the first direction. A liquid dispensing device according to any one of the configurations 1 to 6. (Composition 9) The circulation inspection means is capable of performing a wobble inspection to check the amount of wobble at the point of impact of the liquid from the discharge port based on the inspection pattern. A liquid dispensing device according to any one of configurations 1 to 8. (Composition 10) In the aforementioned twist inspection, the amount of twist is inspected based on the center of gravity position of the inspection pattern. The liquid dispensing device described in configuration 9. (Composition 11) A support portion for a liquid discharge head having a row of discharge ports arranged in a first direction for discharging liquid, and a pressure chamber communicating with the discharge ports and having a pressure generating element that generates pressure for discharging liquid from the discharge ports, A drive control unit for controlling the operation of the liquid discharge head supported by the support portion, the drive control unit capable of performing a discharge pause operation to pause the discharge of liquid from the discharge port, a circulation operation to circulate the liquid in the pressure chamber communicating with the discharge port between the outside of the pressure chamber and the outside of the pressure chamber, and a printing operation to discharge liquid multiple times from the same discharge port to print a long inspection pattern on a recording medium in a second direction intersecting the first direction, A circulation inspection means for inspecting the circulation state of the liquid discharge head based on the length of the inspection pattern in the second direction, A circulating inspection device characterized by being equipped with the following features. (Composition 12) The system further includes notification means for informing the user that the circulation is poor if the length of the second direction of the inspection pattern is shorter than a predetermined threshold. The circulatory inspection device described in configuration 11. [Explanation of symbols]

[0103] 3…Discharge port, 10…Liquid dispensing head, 28…Recording medium

Claims

1. A liquid discharge head having a row of discharge ports arranged in a first direction for discharging liquid, and a pressure chamber communicating with the discharge ports and having a pressure generating element for generating pressure to discharge liquid from the discharge ports, A circulation means for circulating the liquid inside the pressure chamber between the outside of the pressure chamber and the outside of the pressure chamber, A drive control unit that controls the operation of the liquid discharge head and the circulation means, the drive control unit capable of performing a discharge pause operation to pause the discharge of liquid from the discharge port, a circulation operation to circulate the liquid in the pressure chamber communicating with the discharge port between the outside of the pressure chamber and the outside of the pressure chamber, and a printing operation to discharge liquid multiple times from the same discharge port to print a long inspection pattern on a recording medium in a second direction intersecting the first direction, A circulation inspection means for inspecting the circulation state of the liquid discharge head based on the length of the inspection pattern in the second direction, A liquid dispensing device characterized by comprising the following features.

2. The inspection pattern is formed when a plurality of droplets formed by the liquid discharged from the discharge port hitting the recording medium overlap each other in the second direction. The liquid dispensing device according to claim 1.

3. The inspection pattern is formed such that one-quarter to one-half of the diameter of the impact droplet overlaps with an adjacent impact droplet. The liquid dispensing device according to claim 2.

4. If the length of the second direction of the inspection pattern is shorter than a predetermined threshold, the user is notified that the circulation is poor. The liquid dispensing device according to claim 1.

5. The circulation inspection means inspects the circulation state of the liquid discharge head based on the length of the inspection pattern in the second direction, as well as the number of inspection patterns printed on the recording medium. The liquid dispensing device according to claim 1.

6. The drive control unit performs a viscosity control operation to control the viscosity of the liquid inside the discharge port before the discharge pause operation. The liquid dispensing device according to claim 1.

7. In the aforementioned printing operation, liquid is discharged from all the discharge ports constituting the discharge port row at approximately the same timing. The liquid dispensing device according to claim 1.

8. In the printing operation, liquid is discharged at different timings from two adjacent discharge ports in the first direction. The liquid dispensing device according to claim 1.

9. The circulation inspection means is capable of performing a wobble inspection to check the amount of wobble at the point of impact of the liquid from the discharge port based on the inspection pattern. The liquid dispensing device according to claim 1.

10. In the aforementioned twist inspection, the amount of twist is inspected based on the center of gravity position of the inspection pattern. The liquid dispensing device according to claim 9.

11. A support portion for a liquid discharge head having a row of discharge ports arranged in a first direction for discharging liquid, and a pressure chamber communicating with the discharge ports and having a pressure generating element that generates pressure for discharging liquid from the discharge ports, A drive control unit for controlling the operation of the liquid discharge head supported by the support portion, the drive control unit capable of performing a discharge pause operation to pause the discharge of liquid from the discharge port, a circulation operation to circulate the liquid in the pressure chamber communicating with the discharge port between the outside of the pressure chamber and the outside of the pressure chamber, and a printing operation to discharge liquid multiple times from the same discharge port to print a long inspection pattern on a recording medium in a second direction intersecting the first direction, A circulation inspection means for inspecting the circulation state of the liquid discharge head based on the length of the inspection pattern in the second direction, A circulating inspection device characterized by being equipped with the following features.

12. The system further includes notification means for notifying the user that the circulation is poor if the length of the second direction of the inspection pattern is shorter than a predetermined threshold. The circulation inspection device according to claim 11.

Images