Liquid dispensing device

Abstract

To provide a liquid discharge device that can handle a discharge failure according to its cause.SOLUTION: The liquid discharge device comprises: a liquid discharge head 20 that makes a plurality of nozzles 28 discharge liquid to perform printing; a camera 21 that can photograph a nozzle surface 29 on which the plurality of nozzles 28 are arranged; a discharge failure sensing part that senses whether discharge failures occur in the plurality of nozzles 28 or not; a maintenance part 22 that executes maintenance of the liquid discharge head 20; a notification part 23 that performs notification; and a control part 24. When the discharge failure sensing part senses the occurrence of discharge failures, the control part 24 makes the camera 21 photograph the nozzles 28 in which the discharge failures are sensed, guesses a cause of the discharge failures from photographed results, and causes at least either of the maintenance or the notification to be performed on the basis of the guessed cause.SELECTED DRAWING: Figure 1

Description

Technical Field

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[0001] The present invention relates to a liquid ejection device such as a printer.

Background Art

[0002] For example, as in Patent Document 1, there is a liquid ejection device that ejects and prints ink, which is an example of a liquid, from a liquid ejection head. The liquid ejection head ejects ink from a nozzle by displacing a diaphragm. The displaced diaphragm undergoes damped vibration. This damped vibration is also called residual vibration. The residual vibration changes in the attenuation rate of the frequency and amplitude when an abnormality occurs in the ejection. The liquid ejection device includes an ejection abnormality detection circuit, which is an example of a ejection defect detection unit that identifies the cause of ejection failure based on the residual vibration.

Prior Art Documents

Patent Documents

[0003] ​​​​​​​​​​​​​​​​​​​​A liquid ejection device that solves the above problems comprises a liquid ejection head that ejects liquid from multiple nozzles to perform printing, a camera capable of imaging the nozzle surface on which the multiple nozzles are provided, an ejection failure detection unit that detects whether or not there is an ejection failure in the multiple nozzles, a maintenance unit that performs maintenance on the liquid ejection head, a notification unit that provides notification, and a control unit. When the ejection failure detection unit detects an ejection failure, the control unit causes the camera to image the nozzle on which the ejection failure was detected, infers the cause of the ejection failure from the imaging result, and performs at least one of the maintenance and notification based on the inferred cause. [Brief explanation of the drawing]

[0006] [Figure 1] This is a schematic diagram of one embodiment of a liquid dispensing device. [Figure 2] This is a schematic cross-sectional view of the liquid dispensing head. [Figure 3] This is a block diagram showing the electrical configuration of a liquid dispensing device. [Figure 4] This figure shows a calculation model for simple harmonic motion assuming residual vibration of the diaphragm. [Figure 5] This is an explanatory diagram illustrating the relationship between liquid viscosity and residual vibration waveforms. [Figure 6] This is an explanatory diagram illustrating the relationship between air bubble inclusion and residual vibration waveforms. [Figure 7] This is a flowchart of the nozzle inspection routine. [Modes for carrying out the invention]

[0007] [Embodiment] <Liquid discharge device> Hereinafter, an embodiment of a liquid dispensing device will be described with reference to the drawings. The liquid dispensing device is an inkjet printer that prints by dispensing ink, which is an example of a liquid, onto a medium such as paper, cloth, vinyl, plastic parts, or metal parts.

[0008] In the drawings, the direction of gravity is indicated by the Z-axis, assuming the liquid dispensing device 11 is placed on a horizontal plane, and the directions along the horizontal plane are indicated by the X-axis and Y-axis. The X-axis, Y-axis, and Z-axis are orthogonal to each other. In the following explanation, the direction parallel to the X-axis is also referred to as the scanning direction X.

[0009] As shown in Figure 1, the liquid dispensing device 11 may include support legs 12, an outer casing 13, a support base 14, a guide shaft 15, a support mechanism 16, a drive mechanism 17, and a carriage 18. The liquid dispensing device 11 also includes a liquid dispensing head 20, a camera 21, a maintenance unit 22, a notification unit 23, and a control unit 24.

[0010] The support legs 12 support the outer casing 13. The liquid dispensing device 11 may have one or more support legs 12. The outer casing 13 may have an opening 26 that allows access to its interior. By opening the opening 26, the user can perform maintenance on the liquid dispensing device 11, such as cleaning or replacing the liquid dispensing head 20.

[0011] The support base 14 supports the medium 27. The medium 27 is transported on the support base 14 in the transport direction by a transport unit (not shown). In this embodiment, the transport direction is parallel to the Y-axis. After printing on the medium 27 on the support base 14, it is discharged outside the outer case 13.

[0012] The liquid dispensing device 11 may be equipped with one or more guide shafts 15. In this embodiment, the guide shaft 15 extends along the X-axis. The guide shaft 15 guides the movement of the carriage 18. The support mechanism 16 supports the guide shaft 15. The support mechanism 16 may also support the guide shaft 15 so that it can move up and down.

[0013] The carriage 18 holds the liquid ejection head 20. The carriage 18 reciprocates along the guide shaft 15 by the drive of the drive mechanism 17. That is, the carriage 18 moves the liquid ejection head 20 along the guide shaft 15 in the scanning direction X and in the direction opposite to the scanning direction X. In other words, the liquid ejection head 20 is movable in the scanning direction X.

[0014] The liquid ejection head 20 ejects liquid from a plurality of nozzles 28 to perform printing. The liquid ejection head 20 has a nozzle surface 29 provided with the plurality of nozzles 28. The liquid ejection head 20 of the present embodiment prints on the medium 27 supported by the support base 14 by ejecting liquid while moving.

[0015] The carriage 18 may hold one or more first liquid containers 31. The plurality of first liquid containers 31 may each contain a different type of liquid. Different types of liquids are, for example, inks having different colors. Liquid may be supplied to the first liquid container 31 from another second liquid container 32 through a supply tube not shown. The second liquid container 32 may be provided, for example, in the same number as the first liquid container 31.

[0016] The first liquid container 31 and the second liquid container 32 are, for example, tanks, cartridges or packs that contain liquid. The first liquid container 31 and the second liquid container 32 may be the same or different. The first liquid container 31 may be detachably attached to the carriage 18. The second liquid container 32 is disposed inside or outside the exterior case 13. The second liquid container 32 may be detachably attached.

[0017] The liquid ejection device 11 may include one or more cameras 21. The liquid ejection device 11 of the present embodiment includes two cameras 21. In the present embodiment, one camera 21 is also referred to as the first camera 21f, and the other camera 21 is also referred to as the second camera 21s. The first camera 21f and the second camera 21s are provided sandwiching the support base 14 in the scanning direction X.

[0018] Each camera 21 can image the nozzle surface 29. That is, the first camera 21f can image the nozzle surface 29 of the liquid ejection head 20 located at the first object position P1 shown by the solid line in FIG. 1. The second camera 21s can image the nozzle surface 29 of the liquid ejection head 20 located at the second object position P2 shown by the two-dot chain line in FIG. 1.

[0019] The liquid ejection device 11 may include a moving unit 34 that moves the camera 21. The moving unit 34 may move at least one of the plurality of cameras 21. The moving unit 34 of the present embodiment moves the first camera 21f. The moving unit 34 is movable in a moving direction different from the scanning direction X. The moving direction is, for example, a direction parallel to the Y-axis. The moving unit 34 moves the first camera 21f located at a standby position (not shown) in the moving direction to position it at the imaging position Pi. The imaging position Pi is a position where the nozzle 28 of the liquid ejection head 20 located at the first object position P1, which is an example of the object position, can be imaged.

[0020] The liquid ejection device 11 may include one or more covers 35 that protect the camera 21. The liquid ejection device 11 of the present embodiment includes two covers 35. The cover 35 may be fixed or movable.

[0021] The cover 35 that protects the first camera 21f of the present embodiment is fixed. The cover 35 for the first camera 21f covers at least the lens of the first camera 21f among the first cameras 21f located at the standby position. The first camera 21f moves to the imaging position Pi, and the lens comes off the cover 35.

[0022] The cover 35 that protects the second camera 21s of the present embodiment is movable. The cover 35 for the second camera 21s is movable between a covering position that covers at least the lens of the second camera 21s and an exposing position that exposes the lens. The cover 35 for the second camera 21s may be located at the covering position while the second camera 21s is not performing imaging, and may move to the exposing position when the second camera 21s performs imaging.

[0023] The first camera 21f and the second camera 21s may have different imaging ranges. For example, the first camera 21f may magnify and image a portion of the nozzle surface 29. For example, the second camera 21s may image the entire nozzle surface 29.

[0024] If the imaging range in the scanning direction X is a part of the nozzle surface 29, the control unit 24 may adjust the first subject position P1 and the second subject position P2 so that the nozzle 28 to be imaged is within the imaging range. That is, the first subject position P1 and the second subject position P2 are not limited to positions where the center of the liquid discharge head 20 in the scanning direction X is directly above the center of the camera 21, but may be positions where the centers are offset in the scanning direction X. Specifically, the first subject position P1 may be a position where any nozzle 28 can be imaged by the first camera 21f located at imaging position Pi. The second subject position P2 may be a position where any nozzle 28 can be imaged by the second camera 21s. Any nozzle 28 may be, for example, a nozzle 28 in which a discharge failure of the liquid discharge head 20 has been detected.

[0025] The maintenance unit 22 performs maintenance on the liquid discharge head 20. The maintenance unit 22 may include a wiper 37, a cleaning unit 38, and a cleaning member 39. The cleaning unit 38 may include a cap 40 and a suction pump 41. In this embodiment, the wiper 37, cap 40, and cleaning member 39 are individually movable to a position where they can contact the liquid discharge head 20 and a position where they do not contact the liquid discharge head 20.

[0026] The wiper 37 has, for example, a plate-shaped elastic body. The wiper 37 can wipe the nozzle surface 29 of the liquid discharge head 20 by bringing the elastic body into contact with the nozzle surface 29 as the wiper 37 passes over it. Maintenance by which the wiper 37 wipes the liquid discharge head 20 is also called wiping.

[0027] The cap 40 faces the liquid discharge head 20, which is located in a cleaning position (not shown). In this embodiment, the cleaning position is directly above the cap 40. When the cap 40 rises while the liquid discharge head 20 is in the cleaning position, the cap 40 contacts the nozzle surface 29 so as to surround the nozzle 28. By contacting the liquid discharge head 20, the cap 40 forms a closed space between the liquid discharge head 20 and the cap, through which the nozzle 28 opens. This maintenance, in which the cap 40 contacts the nozzle surface 29 so as to surround the nozzle 28, is also called capping. Capping is performed to prevent the nozzle 28 from drying out when the liquid discharge device 11 is idle or stopped.

[0028] The suction pump 41 reduces the pressure in the closed space formed between the cap 40 and the liquid discharge head 20. This forces the liquid in the liquid discharge head 20 to be discharged through the nozzle 28. Maintenance by which the suction pump 41 discharges the liquid is also called suction cleaning. The cleaning unit 38 is capable of performing suction cleaning, which is an example of cleaning that forcibly discharges liquid from the liquid discharge head 20.

[0029] The cap 40 may receive the liquid discharged from the liquid discharge head 20, which is located in the cleaning position. Maintenance involving the discharge of liquid from the liquid discharge head 20 is also called flushing.

[0030] The cleaning member 39 is capable of cleaning the side surface of the liquid discharge head 20. The cleaning member 39 may have an elastic material such as rubber. The cleaning member 39 may also have an absorbent material capable of absorbing liquid.

[0031] The notification unit 23 provides notification. The notification unit 23 may have a display unit 43 capable of displaying various information. The display unit 43 provides notification by displaying information. The display unit 43 may be a monitor or a touch panel that can be operated. The notification unit 23 may have a speaker 44 capable of emitting sound.

[0032] As shown in Figure 2, the liquid dispensing device 11 may include a supply channel 46. The supply channel 46 connects the first liquid container 31 and the liquid dispensing head 20. The liquid discharge head 20 may have a common liquid chamber 48, a plurality of pressure chambers 49, a plurality of communication passages 50, a plurality of actuators 51, a vibrating plate 52, and a housing chamber 53.

[0033] A supply channel 46 is connected to the common liquid chamber 48. Liquid is supplied to the common liquid chamber 48 from the first liquid container 31 via the supply channel 46. Each pressure chamber 49 is connected to a common liquid chamber 48 via a corresponding connecting passage 50, and also to a corresponding nozzle 28. A portion of the wall surface of the pressure chamber 49 is formed by a diaphragm 52.

[0034] The housing chamber 53 is located in a different position from the common liquid chamber 48. The housing chamber 53 houses the actuator 51. The actuator 51 is mounted on the side of the diaphragm 52 opposite to the portion facing the pressure chamber 49.

[0035] The actuator 51 in this embodiment is composed of a piezoelectric element that contracts when a drive voltage is applied. After the diaphragm 52 is deformed by the contraction of the actuator 51 due to the application of the drive voltage, when the application of the drive voltage to the actuator 51 is released, the liquid in the pressure chamber 49, whose volume has changed, is discharged as droplets from the nozzle 28.

[0036] As shown in Figure 3, the control unit 24 comprehensively controls the components of the liquid dispensing device 11. The control unit 24 includes an interface unit 55, a CPU 56, a memory 57, a control circuit 58, and a drive circuit 59. The interface unit 55 transmits and receives data between the external device, the computer 60, and the liquid dispensing device 11. The drive circuit 59 generates a drive signal to drive the actuator 51.

[0037] The CPU 56 is an arithmetic processing unit. The memory 57 is a storage device that reserves an area for storing the CPU 56's program or a working area, and has memory elements such as RAM and EEPROM. The CPU 56 controls the drive mechanism 17, camera 21, maintenance unit 22, notification unit 23, and liquid discharge head 20, etc., via the control circuit 58 according to the program stored in the memory 57.

[0038] The liquid dispensing device 11 includes a group of detectors 62. The group of detectors 62 is controlled by a control unit 24. The group of detectors 62 monitors the conditions inside the liquid dispensing device 11. The group of detectors 62 outputs the detection results to the control unit 24. The group of detectors 62 may include, for example, a linear encoder for detecting the movement of the carriage 18 and a medium detection sensor for detecting the medium 27.

[0039] The detector group 62 includes a discharge failure detection unit 63. The discharge failure detection unit 63 detects whether or not there is a discharge failure in the multiple nozzles 28. The discharge failure detection unit 63 in this embodiment is a circuit that detects the state inside the pressure chamber 49 by detecting the vibration waveform of the pressure chamber 49. The discharge failure detection unit 63 detects whether or not there is a discharge failure in the multiple nozzles 28 based on the residual vibration of the displaced diaphragm 52. The discharge failure detection unit 63 may also include a piezoelectric element that constitutes the actuator 51.

[0040] Multiple actuators 51 are individually driven by a drive circuit 59, thereby partially displacing the diaphragm 52. The displaced diaphragm 52 causes liquid to be discharged from the nozzle 28 corresponding to the driven actuator 51.

[0041] In other words, when a voltage is applied to the actuator 51 by a signal from the drive circuit 59, the diaphragm 52 bends and deforms. This causes pressure fluctuations in the pressure chamber 49. Due to these fluctuations, the diaphragm 52 vibrates for a while. This vibration is called residual vibration. Detecting the state of the pressure chamber 49 and the nozzle 28 leading to the pressure chamber 49 from the state of residual vibration is called nozzle inspection.

[0042] Figure 4 shows a calculation model of simple harmonic motion assuming residual vibration of the diaphragm 52. When the drive circuit 59 applies a drive signal to the actuator 51, the actuator 51 expands and contracts in accordance with the voltage of the drive signal. The diaphragm 52 flexes in accordance with the expansion and contraction of the actuator 51. As a result, the volume of the pressure chamber 49 expands and then contracts. At this time, the pressure generated inside the pressure chamber 49 causes a portion of the liquid filling the pressure chamber 49 to be discharged as droplets from the nozzle 28.

[0043] During the series of operations of the diaphragm 52 described above, the diaphragm 52 vibrates freely at a natural frequency determined by the flow resistance r, which is due to the shape of the liquid flow path and the viscosity of the liquid, the inertance m, which is due to the weight of the liquid in the flow path, and the compliance C of the diaphragm 52. This free vibration of the diaphragm 52 is the residual vibration.

[0044] The calculation model for the residual vibration of the diaphragm 52 shown in Figure 4 can be expressed in terms of pressure P, inertance m, compliance C, and flow resistance r as described above. When pressure P is applied to the circuit in Figure 4, the step response is calculated for the volume velocity u and the following equation is obtained.

[0045]

number

[0046] Figure 5 is an explanatory diagram illustrating the relationship between liquid viscosity and residual vibration waveform. In Figure 5, the horizontal axis represents time, and the vertical axis represents the magnitude of the residual vibration. For example, when the liquid near nozzle 28 dries, the viscosity of the liquid increases, i.e., it thickens. When the liquid thickens, the flow resistance r increases, so the vibration period and the damping of the residual vibration increase.

[0047] Figure 6 is an explanatory diagram of the relationship between air bubble inclusion and residual vibration waveform. In Figure 6, the horizontal axis represents time, and the vertical axis represents the magnitude of the residual vibration. For example, if air bubbles are introduced into the liquid flow path or the tip of the nozzle 28, the inertance m, which is the weight of the liquid, decreases by the amount of the air bubbles compared to when the nozzle 28 is in a normal state. From equation (2), a decrease in m leads to an increase in angular velocity ω, so the vibration period becomes shorter. That is, the vibration frequency increases.

[0048] Furthermore, if foreign matter such as paper dust adheres to the opening of the nozzle 28, the amount of liquid in the pressure chamber 49 and the seepage will increase compared to normal conditions as seen from the diaphragm 52, which is thought to increase the inertance m. The flow resistance r is thought to increase due to the paper dust fibers adhering to the outlet of the nozzle 28. Therefore, when paper dust adheres to the opening of the nozzle 28, the frequency will be lower than during normal discharge, and the frequency of residual vibration will be higher than in the case of increased liquid viscosity.

[0049] If the liquid becomes thicker, bubbles are introduced, or foreign matter adheres to it, the conditions inside the nozzle 28 and pressure chamber 49 become abnormal, and typically the liquid will no longer be discharged from the nozzle 28. As a result, dead pixels will appear in the image recorded on the medium 27. Even if droplets are discharged from the nozzle 28, the amount of droplets may be small, or the direction of flight of the droplets may be off, causing them to miss the target location. A nozzle 28 that exhibits such discharge defects is called an abnormal nozzle.

[0050] As described above, the residual vibration of the pressure chamber 49 connected to the abnormal nozzle is different from the residual vibration of the pressure chamber 49 connected to the normal nozzle 28. Therefore, the discharge failure detection unit 63 detects the state inside the pressure chamber 49 by detecting the vibration waveform of the pressure chamber 49.

[0051] The discharge failure detection unit 63 may infer whether the condition inside the pressure chamber 49 is normal or abnormal based on the vibration waveform of the diaphragm 52. If the condition inside the pressure chamber 49 is abnormal, the nozzle 28 connected to the pressure chamber 49 is presumed to be an abnormal nozzle causing a discharge failure. The control unit 24 may infer whether the condition inside the pressure chamber 49 is abnormal due to the presence of bubbles or due to increased viscosity of the liquid, based on the vibration waveform of the pressure chamber 49. The control unit 24 may also infer the total volume of bubbles present in the pressure chamber 49 and the nozzle 28 connected to the pressure chamber 49, and the degree of increased viscosity of the liquid in the pressure chamber 49 and the nozzle 28 connected to the pressure chamber 49, based on the vibration waveform of the pressure chamber 49.

[0052] The frequency of the vibration waveform detected when bubbles are present in the liquid-filled pressure chamber 49 and nozzle 28 is higher than the frequency of the vibration waveform detected when bubbles are absent from the liquid-filled pressure chamber 49 and nozzle 28. The frequency of the vibration waveform detected when the pressure chamber 49 and nozzle 28 are filled with air is higher than the frequency of the vibration waveform detected when bubbles are present in the liquid-filled pressure chamber 49 and nozzle 28. The larger the size of the bubbles present in the liquid-filled pressure chamber 49 and nozzle 28, the higher the frequency of the vibration waveform.

[0053] The frequency of the vibration waveform detected when the liquid is thickened is lower than the frequency of the vibration waveform detected when the liquid is not thickened. The greater the degree of liquid thickening, the lower the frequency of the vibration waveform. In other words, the drive waveform when the degree of thickening is small is similar to the vibration waveform when foreign matter is adhering near the opening of the nozzle 28. Therefore, when the cause of the discharge failure is foreign matter on the nozzle surface 29, and when the degree of thickening is small, it is difficult to identify the cause of the discharge failure based on the vibration waveform.

[0054] If a discharge failure is detected by the discharge failure detection unit 63, the control unit 24 causes the camera 21 to image the nozzle 28 where the discharge failure was detected. Specifically, if a discharge failure is detected by the discharge failure detection unit 63, the control unit 24 moves the liquid discharge head 20 to the first subject position P1 or the second subject position P2.

[0055] The control unit 24 may select which of the first subject position P1 and the second subject position P2 to move the liquid discharge head 20 to. For example, the control unit 24 may move the liquid discharge head 20 to the subject position closer to the position of the liquid discharge head 20 when a discharge failure is detected. For example, the control unit 24 may move the liquid discharge head 20 according to the range of the nozzle surface 29 to be imaged. That is, for example, if the entire nozzle surface 29 is to be imaged, the liquid discharge head 20 may be moved to the second subject position P2 and imaged by the second camera 21s. For example, if only a part of the nozzle surface 29 is to be imaged, the liquid discharge head 20 may be moved to the first subject position P1 and imaged by the first camera 21f.

[0056] Camera 21 may image the liquid discharge head 20 while it is stopped at the target position, or it may image the liquid discharge head 20 as it passes through the target position. The first camera 21f may image the liquid discharge head 20 while it is moving.

[0057] When moving the liquid discharge head 20 to the first subject position P1, the control unit 24 moves the first camera 21f, which is located in the standby position, to the imaging position Pi. The control unit 24 may also start moving the first camera 21f to the imaging position Pi while the liquid discharge head 20 is moving to the first subject position P1.

[0058] The control unit 24 infers the cause of the dispensing failure from the imaging results of the camera 21. For example, if there is no problem with the nozzle surface 29, the control unit 24 may infer that the cause of the dispensing failure is due to the viscosity of the liquid. If foreign matter adhering to the nozzle surface 29 is covering the nozzle 28, the control unit 24 may infer that the nozzle 28 is blocked by the foreign matter. If the edge of the foreign matter adhering to the nozzle surface 29 is located on the nozzle 28, the control unit 24 may infer that the foreign matter is stuck in the nozzle 28.

[0059] The control unit 24 may also infer the state of the liquid discharge head 20 from the imaging results. For example, the nozzle surface 29 may become dirty due to mist, which is a mist of liquid, adhering to it, or due to liquid splashing around the nozzle 28 caused by air bubbles mixed into the nozzle 28. The control unit 24 may also infer from the imaging results whether or not the nozzle surface 29 is dirty. The control unit 24 may also infer from the imaging results whether or not there are dents, scratches, or marks on the nozzle surface 29 where the cap 40 has made contact.

[0060] Next, the nozzle inspection routine will be explained with reference to the flowchart shown in Figure 7. The nozzle inspection routine is executed when multiple actuators 51 are driven.

[0061] As shown in Figure 7, in step S101, the control unit 24 causes the discharge defect detection unit 63 to perform a nozzle inspection. That is, the discharge defect detection unit 63 detects whether or not there is a discharge defect in the multiple nozzles 28 based on the residual vibration of the diaphragm 52.

[0062] In step S102, the control unit 24 determines whether or not there is a nozzle 28 with a discharge defect. If there is no nozzle 28 with a discharge defect, step S102 becomes NO, and the control unit 24 terminates the process. If there is a nozzle 28 with a discharge defect, step S102 becomes YES, and the control unit 24 proceeds to step S103.

[0063] In step S103, the control unit 24 determines whether the number of times a discharge defect has been detected since the nozzle inspection routine was executed exceeds a threshold number. The threshold number is a preset number of 1 or more. If the number of detections exceeds the threshold number, step S103 becomes YES, and the control unit 24 proceeds to step S104. In step S104, the control unit 24 has the notification unit 23 issue a notification and terminate the process.

[0064] If the number of detections is less than or equal to the threshold number, step S103 becomes NO, and the control unit 24 proceeds to step S105. In step S105, the control unit 24 determines whether the cause of the dispensing failure is increased viscosity of the liquid or the inclusion of air bubbles.

[0065] If the cause of the discharge failure is thickening of the liquid or the inclusion of air bubbles, step S105 becomes YES, and the control unit 24 proceeds to step S106. In step S106, the control unit 24 causes the cleaning unit 38 to perform suction cleaning. In step S107, the control unit 24 causes the wiper 37 to perform wiping. Subsequently, the control unit 24 proceeds to step S101. In step S101, the control unit 24 may cause the liquid discharge head 20 to perform flushing and perform a nozzle inspection based on the residual vibrations associated with the flushing.

[0066] In step S105, if the cause of the dispensing failure is neither increased liquid viscosity nor the inclusion of air bubbles, step S105 becomes NO, and the control unit 24 proceeds to step S108. In step S108, the control unit 24 causes the camera 21 to image the nozzle 28 where the dispensing failure was detected.

[0067] In step S109, the control unit 24 determines whether or not a foreign object is stuck in the nozzle 28. If a foreign object is stuck in the nozzle 28, step S109 becomes YES, and the control unit 24 proceeds to step S110. In step S110, the control unit 24 causes the wiper 37 to perform wiping. Subsequently, the control unit 24 proceeds to step S106. In step S109, for example, if the foreign object is covering the nozzle 28, step S109 becomes NO, and the control unit 24 proceeds to step S106.

[0068] <Operation of the Embodiment> The operation of this embodiment will now be described. The ejection failure detection unit 63 may detect ejection failures based on residual vibrations when liquid is ejected for printing or flushing. The ejection failure detection unit 63 may also detect ejection failures based on residual vibrations when liquid is ejected regardless of printing and flushing, or it may detect ejection failures based on residual vibrations when the diaphragm 52 vibrates to prevent liquid ejection.

[0069] If a ejection failure is detected by the ejection failure detection unit 63, the control unit 24 causes the camera 21 to image the nozzle 28 that has been detected as having an ejection failure. If an ejection failure is detected during printing, the control unit 24 may cause the camera 21 to image the nozzle 28 that has been detected as having an ejection failure after printing is completed. For example, the control unit 24 may cause the camera 21 to image after one command to execute printing has been completed. The control unit 24 may cause the camera 21 to image after printing on one medium 27 has been completed. The control unit 24 may cause the camera 21 to image when the liquid ejection head 20 turns around after printing performed by the liquid ejection head 20 in one direction has been completed. The control unit 24 may change the timing of the camera 21 to image depending on whether the printing performed by the nozzle 28 that has been detected as having an ejection failure can be compensated for by other nozzles 28. That is, if the printing cannot be compensated for by other nozzles 28, the camera 21 may be caused to image when the liquid ejection head 20 turns around. If printing can be supplemented by other nozzles 28, the camera 21 may be allowed to take an image after one command has finished.

[0070] The control unit 24 infers the cause of the ejection failure from the imaging results and performs at least one of maintenance and notification based on the inferred cause. If the cause of the discharge failure, as inferred from the imaging results, is suspected to be foreign matter covering the nozzle 28, the control unit 24 may perform suction cleaning, wiping, and flushing as maintenance. The control unit 24 may also perform a nozzle inspection based on the residual vibration of the diaphragm 52 resulting from the flushing.

[0071] If the cause of the discharge failure, as inferred from the imaging results, is suspected to be a foreign object lodged in the nozzle 28, the control unit 24 may perform maintenance by wiping, followed by suction cleaning, wiping, and flushing. The control unit 24 may also perform a nozzle inspection based on the residual vibration of the diaphragm 52 accompanying the flushing.

[0072] The control unit 24 may instruct the notification unit 23 to notify if the cause cannot be eliminated even after performing maintenance a predetermined number of times. The control unit 24 may also instruct the display unit 43 to display the notification. The control unit 24 may instruct the notification unit 23 to notify at least one of the following: the cause of the discharge failure, maintenance options, and recommended actions to eliminate the cause. The control unit 24 may also instruct the notification unit 23 to notify the number and location of the nozzles 28 with discharge failures.

[0073] The control unit 24 may also provide notification of factors causing dispensing failure, such as increased liquid viscosity, inclusion of air bubbles, adhesion of foreign matter, or damage to the nozzle 28. The control unit 24 may notify the user of at least one of the following maintenance options and recommended actions: suction cleaning, wiping, flushing, cleaning of the liquid discharge head 20 by the user, cleaning of the nozzle 28 by the user, or replacement of the liquid discharge head 20.

[0074] <Effects of the Embodiment> The effects of this embodiment will now be explained. (1) When a discharge failure is detected by the discharge failure detection unit 63, the control unit 24 causes the camera 21 to image the nozzle 28 where the discharge failure was detected. Therefore, even if the cause of the discharge failure is a factor with low detection accuracy by the discharge failure detection unit 63, the cause can be inferred based on the image captured by the camera 21. Thus, the accuracy of identifying the cause can be improved, and appropriate measures can be taken to address the cause of the discharge failure.

[0075] (2) The discharge failure detection unit 63 detects whether or not there is a discharge failure based on the residual vibration of the diaphragm 52. Therefore, the configuration can be simplified compared to, for example, a case where a sensor is provided to detect the discharged liquid.

[0076] (3) The maintenance unit 22 has a cleaning unit 38. The cleaning unit 38 performs cleaning by forcibly discharging liquid from the liquid discharge head 20. Therefore, if the cause of the discharge failure can be removed by discharging the liquid, the condition of the nozzle 28 can be restored by performing cleaning.

[0077] (4) The notification unit 23 has a display unit 43. The display unit 43 displays information based on the cause of the dispensing failure. Therefore, it can inform the user that a dispensing failure has occurred.

[0078] (5) The control unit 24 causes the notification unit 23 to notify the user of the cause of the dispensing failure. Therefore, the user can be informed of the cause of the dispensing failure. (6) The control unit 24 notifies the notification unit 23 of the maintenance options. Therefore, the user can select the maintenance to be performed when a dispensing failure occurs.

[0079] (7) The control unit 24 notifies the notification unit 23 of the recommended operation. Therefore, when a dispensing failure occurs, it is possible to make it easier for the user to select an appropriate operation for the dispensing failure.

[0080] (8) If the ejection failure detection unit 63 detects an ejection failure during printing, the control unit 24 causes the camera 21 to take an image after printing is completed. Therefore, the decrease in throughput can be suppressed compared to when the camera 21 takes an image in the middle of printing.

[0081] (9) The moving unit 34 moves the camera 21. As a result, the camera 21 can be moved to a position where it can image the nozzle 28 where the ejection failure has occurred, and images necessary for inferring the cause of the ejection failure can be easily captured.

[0082] (10) The control unit 24 starts moving the first camera 21f while the liquid discharge head 20 is moving to the first subject position P1. Therefore, compared to the case where the first camera 21f starts moving after the liquid discharge head 20 has been moved to the first subject position P1, the time from when a discharge failure is detected until the first camera 21f takes an image can be shortened.

[0083] (11) If the cause of the dispensing failure cannot be eliminated by maintenance, the control unit 24 will have the notification unit 23 notify the user. Thus, the user can be asked to take action.

[0084] [Example of changes] This embodiment can be implemented with the following modifications. This embodiment and the following modifications can be combined with each other to the extent that they do not contradict each other technically.

[0085] The liquid dispensing device 11 may also be provided with a receiving section for receiving the liquid discharged by flushing, separate from the cap 40. The liquid dispensing device 11 may separately include a moisturizing cap that caps the liquid dispensing head 20 when the liquid dispensing device 11 is idle or stopped, and a suction cap that performs suction cleaning.

[0086] The liquid dispensing device 11 may include a cleaning unit that pressurizes the liquid in the liquid dispensing head 20. The cleaning unit may perform pressurized cleaning, which is an example of cleaning that forcibly discharges the liquid from the liquid dispensing head 20. The cap 40 may receive the liquid discharged from the nozzle 28 in conjunction with the pressurized cleaning.

[0087] The cleaning unit 38 may be equipped with a valve that restricts the flow of liquid in the supply channel 46 or the liquid discharge head 20. The cleaning unit 38 may perform choke cleaning, which is an example of cleaning in which the liquid is forcefully discharged by reducing the pressure in the closed space formed by the cap 40 while the liquid flow is restricted, and then releasing the liquid flow.

[0088] The control unit 24 may perform a combination of different cleaning methods. For example, the control unit 24 may perform suction cleaning as the first cleaning, and if the discharge problem is not resolved, perform choke cleaning as the second cleaning.

[0089] The control unit 24 may instruct the maintenance unit 22 to perform wiping as maintenance based on the suspected cause. The control unit 24 may also instruct the maintenance unit 24 to perform wiping if it infers from the imaging results of the camera 21 that the cause of the ejection failure is a foreign object.

[0090] The control unit 24 may, after inferring the cause of the dispensing failure from the imaging results of the camera 21, issue a notification without performing maintenance. For example, if the liquid dispensing head 20 is in a condition that cannot be restored by maintenance, the control unit 24 may ask the user to take action. If the liquid dispensing head 20 is in a condition that cannot be fixed by cleaning, such as dents or scratches, the control unit 24 may issue a notification to replace the liquid dispensing head 20.

[0091] The control unit 24 may perform maintenance and notification together. The control unit 24 may perform maintenance and also notify that a dispensing malfunction has occurred and that maintenance is being performed.

[0092] The control unit 24 may perform maintenance after issuing a notification. The control unit 24 may also issue a notification that a dispensing malfunction has occurred, and perform maintenance after obtaining the user's consent.

[0093] The liquid dispensing device 11 may include a plurality of movable parts 34. The movable parts 34 may move the corresponding cameras 21 individually. The control unit 24 may start moving the first camera 21f after moving the liquid discharge head 20 to the first subject position P1.

[0094] The control unit 24 may start moving the first camera 21f to the imaging position Pi, and then start moving the liquid discharge head 20 to the first subject position P1. The camera 21 may move in a direction parallel to the Z-axis. For example, if a foreign object is attached to the nozzle surface 29 in a way that it hangs down, imaging while moving along the Z-axis makes it easier to detect the foreign object.

[0095] The control unit 24 may infer the cause of the ejection failure from multiple images captured by the camera 21, or it may infer the cause from some of the images. The discharge failure detection unit 63 may be a sensor that detects the liquid discharged from the nozzle 28. The sensor may be an electrode sensor having an electrode that detects contact with the discharged liquid, or an optical sensor that detects the liquid using light.

[0096] The liquid dispensing device 11 may be a liquid dispensing device that sprays or dispenses liquids other than ink. The state of the liquid dispensed from the liquid dispensing device as minute droplets may include granular, teardrop-shaped, or thread-like forms. The liquid referred to here may be any material that can be dispensed from the liquid dispensing device. For example, the liquid may be any state in which a substance is in the liquid phase, and may include highly or low viscosity liquids, sols, gel water, other inorganic solvents, organic solvents, solutions, liquid resins, liquid metals, and other fluids. The liquid may include not only liquids as a state of matter, but also functional material particles consisting of solids such as pigments and metal particles dissolved, dispersed, or mixed in a solvent. Typical examples of liquids include inks and liquid crystals as described in the above embodiments. Here, ink refers to general water-based inks and oil-based inks, as well as various liquid compositions such as gel inks and hot-melt inks. Specific examples of liquid dispensing devices include devices that dispense liquids containing materials such as electrode materials and colorants in the form of dispersion or dissolution, used in the manufacture of liquid crystal displays, electroluminescent displays, surface-emitting displays, and color filters. Liquid dispensing devices may also be devices that dispense bio-organic substances used in biochip manufacturing, devices that dispense liquid samples used as precision pipettes, printing devices, microdispensers, etc. Liquid dispensing devices may also be devices that dispense lubricating oil to precision machinery such as watches and cameras with pinpoint accuracy, or devices that dispense transparent resin liquids such as ultraviolet-curing resins onto substrates to form minute hemispherical lenses, optical lenses, etc. used in optical communication elements. Liquid dispensing devices may also be devices that dispense etching solutions such as acids or alkalis to etch substrates.

[0097] The technical concepts and their effects that can be understood from the embodiments and modifications described above are described below. (A) The liquid ejection device comprises a liquid ejection head that ejects liquid from a plurality of nozzles to perform printing, a camera capable of imaging the nozzle surface on which the plurality of nozzles are provided, an ejection failure detection unit that detects whether or not there is an ejection failure in the plurality of nozzles, a maintenance unit that performs maintenance on the liquid ejection head, a notification unit that provides notification, and a control unit. When the ejection failure detection unit detects the ejection failure, the control unit causes the camera to image the nozzle on which the ejection failure was detected, infers the cause of the ejection failure from the imaging result, and performs at least one of the maintenance and notification based on the inferred cause.

[0098] In this configuration, when a discharge failure is detected by the discharge failure detection unit, the control unit causes the camera to capture an image of the nozzle where the discharge failure was detected. Therefore, even if the cause of the discharge failure is due to a low detection accuracy by the discharge failure detection unit, the cause can be inferred based on the camera's image. Consequently, the accuracy of identifying the cause can be improved, and appropriate countermeasures can be taken for the cause of the discharge failure.

[0099] (B) In a liquid dispensing device, the liquid dispensing head has a plurality of actuators and a vibrating plate, the plurality of actuators are individually driven by a drive circuit to partially displace the vibrating plate, the displaced vibrating plate discharges the liquid from the nozzles corresponding to the driven actuators, and the dispensing failure detection unit may detect whether or not there is a dispensing failure in the plurality of nozzles based on the residual vibration of the displaced vibrating plate.

[0100] In this configuration, the dispensing failure detection unit detects the presence or absence of a dispensing failure based on the residual vibration of the diaphragm. Therefore, the configuration can be simplified compared to, for example, a case where a sensor is provided to detect the dispensed liquid.

[0101] (C) In a liquid dispensing device, the maintenance unit has a cleaning unit capable of performing cleaning that forcibly discharges the liquid from the liquid dispensing head, and the control unit may have the cleaning performed as maintenance.

[0102] In this configuration, the maintenance unit includes a cleaning unit. The cleaning unit performs cleaning by forcibly draining liquid from the liquid discharge head. Therefore, if the cause of the discharge failure can be removed by draining the liquid, the nozzle condition can be restored by performing the cleaning.

[0103] (D) In ​​a liquid dispensing device, the notification unit has a display unit capable of displaying various information, and the control unit may cause the display unit to display information as notification. In this configuration, the notification unit has a display unit. The display unit displays information based on the cause of the dispensing failure. Therefore, it can inform the user that a dispensing failure has occurred.

[0104] (E) In a liquid dispensing device, the control unit may cause the notification unit to notify the factor. With this configuration, the control unit notifies the notification unit of the cause of the dispensing failure. Therefore, the user can be informed of the cause of the dispensing failure.

[0105] (F) In a liquid dispensing device, the control unit may have the notification unit notify the maintenance options. In this configuration, the control unit notifies the notification unit of the maintenance options. Therefore, the user can select the maintenance to be performed when a dispensing malfunction occurs.

[0106] (G) In a liquid dispensing device, the control unit may cause the notification unit to notify the notification unit of recommended actions to eliminate the factors. In this configuration, the control unit notifies the notification unit of the recommended operation. Therefore, when a dispensing malfunction occurs, it becomes easier for the user to select the appropriate operation for the malfunction.

[0107] (H) In the liquid dispensing device, if a dispensing defect is detected during printing, the control unit may, after the printing is completed, have the camera capture an image of the nozzle in which the dispensing defect was detected.

[0108] In this configuration, if the ejection defect detection unit detects an ejection defect during printing, the control unit will have the camera capture an image after printing is complete. Therefore, the decrease in throughput can be suppressed compared to when the camera captures an image during printing.

[0109] (I) The liquid dispensing device may further include a movable part that can move the camera. In this configuration, the moving unit moves the camera. Therefore, the camera can be moved to a position where it can image the nozzle where the ejection failure has occurred, and images necessary for inferring the cause of the ejection failure can be easily captured.

[0110] (J) In a liquid dispensing device, the liquid dispensing head is movable in the scanning direction, the moving unit is capable of moving the camera in a direction different from the scanning direction, the camera located at the imaging position is capable of imaging the nozzle of the liquid dispensing head located at the subject position where the dispensing failure has been detected, and when the dispensing failure detection unit detects the dispensing failure, the control unit may start moving the camera to the imaging position while the liquid dispensing head is moving to the subject position.

[0111] In this configuration, the control unit starts moving the camera while the liquid discharge head is moving to the subject position. Therefore, compared to the case where the camera starts moving after the liquid discharge head has moved to the subject position, the time from when a discharge failure is detected until the camera takes an image can be shortened.

[0112] (K) In a liquid dispensing device, if the control unit cannot eliminate the cause even after performing the maintenance a predetermined number of times, it may cause the notification unit to give the notification. With this configuration, if the cause of the dispensing failure cannot be eliminated through maintenance, the control unit will have the notification unit issue a notification. Therefore, the user can be asked to take action. [Explanation of symbols]

[0113] 11...Liquid dispensing device, 12...Support legs, 13...Outer case, 14...Support base, 15...Guide shaft, 16...Support mechanism, 17...Drive mechanism, 18...Carriage, 20...Liquid dispensing head, 21...Camera, 21f...First camera, 21s...Second camera, 22...Maintenance unit, 23...Notification unit, 24...Control unit, 26...Opening / closing unit, 27...Media, 28...Nozzle, 29...Nozzle surface, 31...First liquid container, 32...Second liquid container, 34...Moving unit, 35...Cover, 37...Wiper, 38...Cleaning 39...Cleaning component, 40...Cap, 41...Suction pump, 43...Display unit, 44...Speaker, 46...Supply channel, 48...Common liquid chamber, 49...Pressure chamber, 50...Connecting passage, 51...Actuator, 52...Diaphragm, 53...Housing chamber, 55...Interface unit, 56...CPU, 57...Memory, 58...Control circuit, 59...Drive circuit, 60...Computer, 62...Detector group, 63...Discharge failure detection unit, P1...First subject position, P2...Second subject position, Pi...Imaging position, X...Scanning direction.

Claims

1. A liquid ejection head that prints by ejecting liquid from multiple nozzles, A camera capable of imaging the nozzle surface on which the plurality of nozzles are provided, A discharge failure detection unit that detects whether or not there is a discharge failure in the plurality of nozzles, A maintenance unit for performing maintenance on the liquid discharge head, The news department that provides the information, Control unit and Equipped with, If the discharge failure detection unit detects the discharge failure, the control unit will... The nozzle, which was detected as good, is imaged by the camera, and the cause of the discharge failure is determined from the imaging results. Based on the factors inferred, at least one of the maintenance and notification Make it run, The control unit has determined that the suspected cause is a dent or scratch on the nozzle surface that cannot be addressed by cleaning. In this case, the cause is a dent or scratch on the nozzle surface, and the liquid discharge head is replaced. To provide the aforementioned notification that this is the recommended action, A liquid dispensing device characterized by the following features.

2. The liquid discharge head has a plurality of actuators and a vibrating plate, The plurality of actuators are individually driven by a drive circuit to move the diaphragm Partially displace, The displaced diaphragm moves forward from the nozzle corresponding to the driven actuator. Discharge the liquid, The discharge failure detection unit detects the residual vibration of the displaced diaphragm and the plurality of nozzles Liquid dispensing apparatus according to claim 1, characterized by detecting the presence or absence of the aforementioned dispensing failure. 。

3. The maintenance unit forcibly discharges the liquid from the liquid discharge head. It has a cleaning unit capable of performing cleaning, The control unit is characterized by performing the cleaning as maintenance. The liquid dispensing device according to claim 1 or claim 2.

4. The aforementioned notification unit has a display unit capable of displaying various types of information, The control unit is characterized in that it causes the display unit to display the notification. A liquid dispensing device according to any one of claims 3.

5. The control unit is characterized by causing the notification unit to notify the maintenance options. A liquid dispensing device according to any one of claims 1 to 4.

6. The control unit has the notification unit notify it of recommended actions to eliminate the factor. A liquid dispensing device as described in any one of claims 1 to 5.

7. If the ejection failure is detected during printing, the control unit will, after the printing is completed, The nozzle in which the discharge failure was detected is captured by the camera, characterized in that the nozzle is imaged. A liquid dispensing device according to any one of claims 1 to 6.

8. Claims 1 to 7 further characterized by comprising a movable part that allows the camera to move. A liquid dispensing device as described in any one of the items.

9. The liquid dispensing head is movable in the scanning direction, The moving unit is capable of moving the camera in a direction different from the scanning direction. The camera located at the imaging position captures the discharge of the liquid discharge head located at the subject position. The nozzle in which a defect has been detected can be imaged, If the discharge failure detection unit detects the discharge failure, the control unit will... While the output head is moving to the subject position, the movement of the camera to the imaging position is opened. The liquid dispensing device according to claim 8, characterized by starting the process.

10. The control unit can eliminate the factor even if the maintenance is performed a predetermined number of times. If not, the notification unit is made to perform the notification, as is the case of claims 1 to 9. A liquid dispensing device as described in any one of the items.

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