Inspection device and liquid discharge device

Abstract

To provide an inspection device and a liquid discharge device which are capable of reducing computation load, suppressing enlargement of the device, and detecting a discharge surface of a discharge head.SOLUTION: An inspection device inspects the ejection state of liquid ejected from a discharge head having one or more nozzles of a liquid ejection device, comprising an imaging device that captures an image by detecting the ejection state of liquid ejected from the discharge head as a luminance change, and a detection unit that detects a position of a discharge surface of the discharge head in a captured image in which the luminance change is detected by the imaging device by changing a relative position between the discharge head and the imaging device.SELECTED DRAWING: Figure 11

Description

Technical Field

[0001] The present invention relates to an inspection apparatus and a liquid ejection apparatus.

Background Art

[0002] In an inkjet liquid ejection apparatus, in order to eliminate problems with ink ejection from an ink ejection head, techniques for cleaning dirt on nozzles of the ink ejection head are known.

[0003] As a technique for detecting problems with ink ejection from such an ink ejection head, a technique is disclosed in which the droplet state of ink ejected from an ink ejection head is calculated for the speed and flight direction of ink droplets by an optical detection device including a stroboscopic light source and a camera, and cleaning is performed when the values are outside the allowable range (for example, Patent Document 1). When there is an ink liquid pool near the nozzle, the ink near the nozzle thickens due to drying, or thickens due to precipitation of solid components in the ink near the nozzle, the speed of the flying ink droplets becomes slow, the bend becomes large, and the amount tends to change, but after ejecting several drops, it may enter a stable flying state. Therefore, in such a method using a stroboscopic light source, since the average positions of a plurality of ink droplets are photographed to detect the speed, bend, amount, etc., the speed, bend, amount, etc. of the first drop cannot be detected. To solve this, there is a method of photographing at a high frame rate like a high-speed camera and photographing the ejection state from the first drop. However, in a high-speed camera, since the calculation load is high, a large cooling device is required for the camera and the device becomes large. To solve this, there is a method of recording only the moving part in the image, that is, the part where a luminance difference (luminance change) occurs, as a captured image, and photographing at a high frame rate and with a low calculation load. With this method, it is possible to capture the flying state of ink droplets from the first drop with a low calculation load and without the need for a cooling device.

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, when using a camera that records only the portions where a luminance difference (luminance change) occurs as the captured image, unlike a camera using strobe light and a high-speed camera, it is impossible to photograph the ejection surface of the ink ejection head where no luminance difference occurs. Therefore, there is a problem that a reference position for detecting the speed, bending, etc. of ink droplets cannot be recognized.

[0005] The present invention has been made in view of the above circumstances, and an object thereof is to provide an inspection device and a liquid ejection device that can reduce the calculation load, suppress the increase in the size of the device, and detect the ejection surface of the ejection head.

Means for Solving the Problems

[0006] In order to solve the above-described problems and achieve the object, the present invention is an inspection device for inspecting the ejection state of a liquid ejected from an ejection head having one or a plurality of nozzles of a liquid ejection device, including: an imaging device that captures an image by detecting the ejection state of the liquid ejected from the ejection head as a luminance change; and a detection unit that detects the position of the ejection surface of the ejection head in a captured image in which a luminance change is detected by the imaging device by changing the relative position between the ejection head and the imaging device.

Effects of the Invention

[0007] According to the present invention, the calculation load can be reduced, the increase in the size of the device can be suppressed, and the ejection surface of the ejection head can be detected.

Brief Description of the Drawings

[0008]

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Embodiments for Carrying Out the Invention

[0009] Hereinafter, embodiments of the inspection apparatus and the liquid ejection apparatus according to the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited by the following embodiments, and the constituent elements in the following embodiments include those that can be easily conceived by those skilled in the art, those that are substantially the same, and those within the so-called equivalent range. Furthermore, various omissions, substitutions, changes, and combinations of the constituent elements can be made without departing from the gist of the following embodiments.

[0010] (Overall Configuration of Liquid Coating Apparatus) FIG. 1 is a diagram showing an example of the overall configuration of a liquid coating apparatus according to an embodiment. With reference to FIG. 1, the overall configuration of the liquid coating apparatus 1 according to the present embodiment will be described.

[0011] The liquid coating apparatus 1 shown in FIG. 1 is an apparatus (an example of a liquid ejection apparatus) that divides a wide liquid coating area on a road surface or a building wall surface (hereinafter sometimes referred to as a printing surface) into a plurality of printing areas, sequentially moves to each printing area, and divides the printing data for printing on the liquid coating area into a plurality of printing images for printing. FIG. 1(a) is a side view of the liquid coating apparatus 1, and FIG. 1(b) is a plan view of the liquid coating apparatus 1 as viewed from above. Note that "printing" means applying or spraying ink onto the printing surface.

[0012] As shown in FIG. 1, the liquid coating apparatus 1 includes a printing unit 21 and a control unit 22. Note that in the liquid coating apparatus 1, the printing unit 21 and the control unit 22 may each have a separate system configuration.

[0013] The printing unit 21 is a unit for discharging ink while moving to perform printing on the printing surface. Note that the "ink" is a liquid that is applied or sprayed onto the printing surface. As shown in FIG. 1, the printing unit 21 includes a carriage 2, a rail 3, a three-dimensional camera 7, a two-dimensional camera 8, a GNSS (Global Navigation Satellite System) receiver 9, a tire 10, a frame 11, a structure 12, and an inspection device 50.

[0014] The carriage 2 mounts an ink ejection head 2a described later and moves in the main scanning direction (arrow A shown in FIG. 1(b)) along the rail 3. When the rail 3 moves in the sub-scanning direction (arrow B shown in FIG. 1(b)), the carriage 2 moves in the sub-scanning direction. The carriage 2 reciprocates in the main scanning direction along the rail 3 by a head movement mechanism 23 (see FIG. 10 described later) composed of a belt, a pulley, a motor, and the like.

[0015] The rail 3 is a rail member that supports the carriage 2 to move in the main scanning direction and is horizontally supported by the frame 11 so as to be movable in the sub-scanning direction. The rail 3 reciprocates on the frame 11 in the sub-scanning direction orthogonal to the main scanning direction by a rail movement mechanism 24 (see FIG. 10 described later) composed of a belt, a pulley, a motor, and the like.

[0016] That is, the carriage 2 mounted with the ink ejection head 2a can freely move in the front-rear direction (sub-scanning direction) and the left-right direction (main scanning direction) on the plane surrounded by the frame 11 of the liquid application device 1.

[0017] The three-dimensional camera 7 is a three-dimensional shape measurement device for surrounding measurement that is supported by the front part of the frame 11 and images the periphery of the liquid application device 1. Note that the three-dimensional camera 7 may be powered from a battery mounted on itself, or may be powered from the power supply system 5 assuming continuous operation.

[0018] The two-dimensional camera 8 is an imaging device that images the printing surface, the printed image printed on the printing surface, and the vicinity of the printed image. Therefore, the imaging direction of the two-dimensional camera 8 is downward. The two-dimensional camera 8 transmits the captured imaging image to the controller unit 6 described later. Note that the two-dimensional camera 8 may be powered from a battery mounted on itself, or may be powered from the power supply system 5 assuming continuous operation.

[0019] The GNSS receiver 9 is a receiving device that receives a positioning signal for measuring the current position on the earth from positioning satellites based on GNSS (e.g., GPS (Global Positioning System), etc.). The GNSS receiver 9 transmits the received positioning signal to the controller unit 6.

[0020] The tires 10 are members that are attached to the lower part of the frame 11 and rotate by being pushed by an operator or the like to move the printing unit 21. As a result, the liquid application device 1 can be moved in four directions: forward, backward, left, and right.

[0021] The frame 11 is a frame structure that constitutes the base of the printing unit 21 and supports the rail 3, the three-dimensional camera 7, the GNSS receiver 9, the structure 12, etc. from below.

[0022] The structure 12 is a structure formed by assembling pipes or the like that form the outer frame of the printing unit 21. The two-dimensional camera 8 is mounted on the upper surface of the structure 12.

[0023] The inspection device 50 is a device for inspecting the flying state of ink droplets ejected from the ink ejection head 2a (ejection head) of the carriage 2. The configuration of the inspection device 50 will be described later with reference to FIG. 2. Note that the flying state can also be referred to as the ejection state.

[0024] As shown in FIG. 1, the control unit 22 includes an ink supply system 4, a power supply system 5, and a controller unit 6.

[0025] The ink supply system 4 is a unit that supplies ink for printing to the ink ejection head 2a of the carriage 2 via a pipe 4a that is an ink flow path. In this embodiment, the ink supply system 4 is assumed to move following the printing unit 21, but it is not limited to this, and it may be self-propelled independently of the printing unit 21.

[0026] The power supply system 5 is a unit that supplies power for driving the control unit 22, the head movement mechanism 23, the ink ejection head 2a, and the like.

[0027] The controller unit 6 is a control unit for controlling the operation of the liquid application device 1. The controller unit 6 controls, for example, the operations of the head movement mechanism 23, the rail movement mechanism 24, and the ink ejection head 2a, or estimates the position of the liquid application device 1 from the positioning signal received by the GNSS receiver 9. The controller unit 6 uses the captured image captured by the three-dimensional camera 7 mainly for avoiding contact with obstacles and the like using a method such as image correlation, or for estimating the movement amount and posture of the liquid application device 1. Further, the controller unit 6 stores the positioning signal received by the GNSS receiver 9 as odometry information such as the cumulative movement amount of the liquid application device 1. Note that the liquid application device 1 may include a plurality of GNSS receivers 9, and the controller unit 6 may correct the position information from the positioning signals received by the plurality of GNSS receivers 9.

[0028] Note that although the liquid application device 1 shown in FIG. 1 has been described as being moved mainly by being pushed by an operator, it is not limited to this, and the liquid application device 1 may be a self-propelled device provided with a motor or the like capable of controlling the rotation of the tire 10.

[0029] (Configuration of the inspection device) FIG. 2 is a diagram showing an example of the configuration of the inspection apparatus according to the embodiment. FIG. 3 is a diagram for explaining the positional relationship between the inspection apparatus and the maintenance unit in the liquid application apparatus according to the embodiment. With reference to FIGS. 2 and 3, the configuration of the inspection apparatus 50 according to the present embodiment will be described.

[0030] As shown in FIG. 2, the inspection apparatus 50 includes a camera 51, a light source 52, an air discharge receiver 53, and a frame 54.

[0031] As described above, the carriage 2 is supported by the rail 3 so as to be reciprocally movable in the A direction (main scanning direction), and is equipped with an ink discharge head 2a that discharges ink onto the printing surface. The ink discharge head 2a is a thermal (bubble jet) or piezo ink jet head. Note that the nozzles of the ink discharge head 2a may be provided singly or in plurality for a single color or ink material, or may be provided in plurality for each color or ink material. Note that the inspection apparatus 50 may be provided with an encoder that can detect the movement amount and speed of the carriage 2.

[0032] The camera 51 is an imaging device (hereinafter sometimes referred to as an event-based camera) that can record only the portions where a luminance difference (luminance (intensity) change) occurs as data in the captured image. The operation of the camera 51, which is an event-based camera, will be described later with reference to FIGS. 4 to 7. Further, as shown in FIG. 2, the camera 51 includes an optical system 51a that is a telecentric lens that operates so that the principal ray is parallel to the optical axis. The operation of the optical system 51a, which is a telecentric lens, will be described later with reference to FIG. 8. The camera 51 is installed such that at least the ejection surface of the ink discharge head 2a of the carriage 2 enters the angle of view when the carriage 2 moves in the main scanning direction to an inspection position for inspecting the flying state of the ink droplets ejected from the ink discharge head 2a.

[0033] The light source 52 is a light source such as an LED (Light Emitting Diode) that faces the camera 51 and is arranged on the side opposite to the camera 51 with respect to the carriage 2 when the carriage 2 is at the inspection position. That is, the light source 52 irradiates light toward the imaging surface of the camera 51 from behind the ink ejection head 2a and the ink ejected from the ink ejection head 2a. Thereby, it is possible to easily generate a luminance difference in the behavior of the ink in the captured image.

[0034] The empty ejection receiver 53 is a receiving member that is fixed to a position on the frame 54 directly below the ink ejection head 2a of the carriage 2 when the carriage 2 moves to the inspection position and receives the ink ejected for inspection from the ink ejection head 2a.

[0035] The frame 54 is, for example, a U-shaped frame member, and as shown in FIG. 2, it is a frame member that fixes the camera 51, the light source 52, and the empty ejection receiver 53.

[0036] Note that the inspection device 50 may be detachable from the liquid application device 1 as one unit.

[0037] In the inspection device 50 having such a configuration, when inspecting the ejection of ink by the ink ejection head 2a, as described above, the carriage 2 moves to the inspection position and stops. Then, the light source 52 irradiates light, the ink ejection head 2a starts ink ejection for inspection, and the camera 51 starts shooting. As described above, since the light source 52 irradiates light toward the imaging surface of the camera 51 from behind the ink ejection head 2a and the ink ejected from the ink ejection head 2a, ink droplets are imaged as shadows on the camera 51. The reason for imaging the ink droplets as shadows is to create a state where there is light on the entire surface and there is no luminance difference when there are no ink droplets, and when the ink droplets move, they become shadows, generating a large luminance difference, so that the camera 51 can easily detect the ink droplets.

[0038] Further, as shown in FIG. 3, the liquid application device 1 has a maintenance unit 13. The maintenance unit 13 includes, for example, a cleaning device 14 described later for cleaning nozzles on the ejection surface of the ink ejection head 2a.

[0039] The carriage 2 including the ink ejection head 2a is located at a position (standby position) corresponding to the maintenance unit 13 outside the printing area PAR before printing, and moves to an inspection position to inspect the flying state of ink droplets when a printing command is generated. Then, at the inspection position, if the ink ejection state is within the allowable range, the carriage 2 moves onto the printing area PAR to start printing.

[0040] In the example shown in FIG. 3, the maintenance unit 13 and the inspection device 50 are arranged on both sides sandwiching the printing area PAR, but it is not limited thereto, and they may be arranged adjacent to each other.

[0041] (Regarding the operation of the event-based camera) FIG. 4 is a diagram for explaining the outline of the operation of the event-based camera. FIG. 5 is a diagram for explaining the detection operation of ink droplets in the inspection device according to the embodiment. FIG. 6 is a diagram for explaining the detection operation of the ejection surface of the ink ejection head in the inspection device according to the embodiment. FIG. 7 is a diagram showing an example of a captured image of ink droplets detected in the inspection device according to the embodiment. The operation of the event-based camera (camera 51) will be described with reference to FIGS. 4 to 7.

[0042] An event-based camera detects, as an event, a change in the luminance of light detected for each pixel of an imaging element when the change exceeds a predetermined threshold value, and records the coordinates (X, Y), time, and polarity (whether the luminance changes in the bright direction or the dark direction) of the pixel where the event has occurred as an imaging image. That is, the imaging image can be an image composed of pixel values of three-valued data: plus (luminance change in the bright direction), minus (luminance change in the dark direction), and no data, for each imaging time. Therefore, it is not necessary to perform gray-scale conversion or binarization processing, etc., which are often used in image processing. Thus, since the imaging image contains only data of the coordinates, time, and polarity of the pixels where luminance changes are detected, the computational load of processing can be reduced. As the event-based camera, for example, known cameras disclosed in Japanese Patent Application Laid-Open No. 2020-503752 and Japanese Patent Application Laid-Open No. 2020-505801 can be used.

[0043] For example, in the example shown in FIG. 4, a ball moving on a parabola is captured. However, the imaging image BIM1 captured at the timing of throwing up contains only the data (coordinates, time, polarity) of the pixels corresponding to the part of the ball located on the left side where a luminance change has occurred. The imaging image BIM2 capturing the ball that has reached the highest point of the parabola contains only the data of the pixels corresponding to the part of the ball where a luminance change has occurred. Further, the imaging image BIM3 capturing the ball that is descending contains only the data of the pixels corresponding to the part of the ball where a luminance change has occurred.

[0044] The camera 51, which is an event-based camera capable of the above-described operation, as shown in FIG. 5, when imaging the ink droplets ejected for inspection from the ink ejection head 2a, since the ink droplets are moving and there is a luminance difference (luminance change), they can be imaged. On the other hand, when the carriage 2 mounting the ink ejection head 2a ejects ink droplets for inspection, since it is not moving and is stopped at the inspection position, as shown in FIG. 6(a), the camera 51 cannot image the carriage 2. If the carriage 2 cannot be imaged, the position of the ejection surface of the ink ejection head 2a, which is the reference position for calculating the speed and curvature of the ink droplets, cannot be recognized. Therefore, in the present embodiment, as shown in FIG. 6(b), when the carriage 2 moves to the inspection position, that is, when the carriage 2 moves parallel to the ejection surface of the ink ejection head 2a, the camera 51 images the carriage 2. Note that the moving direction parallel to the ejection surface of the ink ejection head 2a is an example of the "predetermined one direction" of the present invention. Thereby, the position of the ejection surface of the ink ejection head 2a can be detected as an edge that causes a luminance difference, and based on this position, it is possible to calculate the speed and curvature of the ink droplets. Here, the position of the ejection surface of the ink ejection head 2a is the position and angle of the ejection surface of the ink ejection head 2a in the captured image.

[0045] Note that, as shown in FIG. 6(c), even when the carriage 2 is tilted and fixed with respect to the angle of view of the camera 51, by moving the carriage 2 in a predetermined one direction, it is possible to detect the ejection surface of the ink ejection head 2a.

[0046] As described above, after the ejection surface of the ink ejection head 2a is detected when the carriage 2 moves to the inspection position, the ink ejection head 2a ejects ink droplets for inspection, and the camera 51 captures an image of the ink droplets. Here, FIG. 7 shows an example of the ink droplets imaged by the camera 51. FIG. 7(a) shows an imaging image immediately after being ejected from the ejection surface of the ink ejection head 2a, and FIG. 7(b) shows an imaging image in a state where a predetermined time has elapsed from the state of FIG. 7(a). As shown in the imaging images in FIG. 7, the ink droplets can be recognized as an aggregate of pixel values of plus and minus polarities. Further, since the position of the ejection surface is detected, based on the position, the speed of the ink droplets and the bend of the ink droplets with respect to the ejection surface (the inclination with respect to the ejection surface of the trajectory of the ink droplets) can be calculated and compared for each nozzle. Also, it is possible to calculate the amount of ink of the ink droplets from the size of the ink droplets included in the imaging image. Furthermore, it is also possible to count the actual number of droplets of the main droplet, satellite, and mist in the ejection signal for ejecting one drop from the nozzle of the ink ejection head 2a.

[0047] Also, as shown in FIG. 7, the rear end of the flying ink droplet becomes positive polarity, there is no ligament, and it is clearly shown that the ink droplet disappears. Here, the ligament is a tail-like ink portion that extends to the rear end side in the ejection direction after the ejection of the ink droplet. Also, when a ligament is generated when the ink droplet is ejected downward, the ligament stays in place and is on the corresponding pixel, so there is no change in polarity and it does not appear in the imaging image. However, when the ink ejection head 2a ejects while moving in one direction as shown in FIG. 6, since the ink droplet also moves in the moving direction of the ink ejection head 2a, when a ligament is generated, the ligament with the moving direction side of the ink ejection head 2a being negative polarity and the opposite side being positive polarity can be detected in the imaging image.

[0048] (Operation of calculating pixel size) FIG. 8 is a diagram for explaining the operation of a telecentric lens mounted on an event-based camera of an inspection apparatus according to an embodiment. FIG. 9 is a diagram for explaining the operation of calculating the pixel size in the inspection apparatus according to the embodiment. With reference to FIGS. 8 and 9, the operation of the optical system 51a, which is a telecentric lens mounted on the camera 51 of the inspection apparatus 50 according to the present embodiment, and the operation of calculating the pixel size will be described.

[0049] First, as shown in FIG. 8(a), it is assumed that two rectangular parallelepiped objects of the same size are arranged at positions with different depths in the imaging direction of the camera 51. In this case, when imaging is performed using a standard lens having a fixed focal point, as shown in FIG. 8(b), due to the difference in depth, the object in the foreground appears large and the object in the background appears small. Therefore, when the distance from the subject changes, the size of the subject changes, so when an ink droplet is used as the subject, it is impossible to accurately calculate the speed, bend, and amount.

[0050] On the other hand, as described above, the optical system 51a mounted on the camera 51 is a telecentric lens, and the chief ray from the subject is made parallel to the optical axis of the optical system 51a. As a result, as shown in FIG. 8(c), even if the arrangement in the depth direction is different, objects of the same size are imaged as the same size. Therefore, no matter at what depth the ink droplet is imaged, it is possible to calculate the pixel size, which is the actual distance / length corresponding to one pixel in the captured image, and the speed, bend, and amount of the ink droplet can be accurately calculated. Specifically, as shown in FIG. 9, during the discharge inspection operation, the inspection apparatus 50 divides the actual movement amount of the carriage 2 by the number of pixels corresponding to the movement amount of the carriage 2 in the captured image, thereby calculating the pixel size, which is the actual distance / length corresponding to one pixel. If the pixel size of the event-based camera and the magnification of the telecentric lens are known, the pixel size may be calculated by multiplying them.

[0051] (Hardware Configuration of Liquid Coating Apparatus) FIG. 10 is a diagram showing an example of the hardware configuration of the liquid application apparatus according to the embodiment. While referring to FIG. 10, the hardware configuration of the liquid application apparatus 1 according to the present embodiment will be described.

[0052] As shown in FIG. 10, the liquid application apparatus 1 includes a carriage 2, a controller unit 6, a three-dimensional camera 7, a two-dimensional camera 8, a GNSS receiver 9, a cleaning device 14, an operation panel 15, a head movement mechanism 23, a rail movement mechanism 24, and an inspection device 50.

[0053] The carriage 2 is equipped with an ink ejection head 2a that ejects ink onto the printing surface, moves in the main scanning direction along the rail 3 shown in FIG. 1, and moves in the sub-scanning direction as the rail 3 moves in the sub-scanning direction.

[0054] The controller unit 6 includes a CPU (Central Processing Unit) 61, a memory 62, an I / F 63, and a unit control circuit 64.

[0055] The CPU 61 is an arithmetic unit that comprehensively controls the operation of the liquid application apparatus 1. The CPU 61 performs data communication with the memory 62, the I / F 63, and the unit control circuit 64 via a bus. Further, the CPU 61 performs drive control of the head movement mechanism 23, the rail movement mechanism 24, and the ink ejection head 2a via the unit control circuit 64, and estimates the self-position of the liquid application apparatus 1 from the positioning signal received by the GNSS receiver 9.

[0056] The memory 62 is a storage medium such as a ROM (Read Only Memory) or a RAM (Random Access Memory) that stores programs used for driving the CPU 61. Further, the memory 62 is used as a work area for the CPU 61.

[0057] I / F 63 is a communication interface for connecting various external devices 30 such as tablet terminals, smartphones, PCs (Personal Computers), servers, and notebook PCs. In this embodiment, I / F 63 performs data communication with the inspection device 50.

[0058] The unit control circuit 64 is a control circuit that controls the operations of the head movement mechanism 23, the rail movement mechanism 24, and the ink ejection head 2a according to the control by the CPU 61.

[0059] The three-dimensional camera 7 and the two-dimensional camera 8 each transmit the captured image to the CPU 61 of the controller unit 6.

[0060] The GNSS receiver 9 receives a positioning signal for measuring the current position on the earth from positioning satellites based on GNSS (e.g., GPS, etc.) and transmits the positioning signal to the CPU 61 of the controller unit 6.

[0061] The cleaning device 14 is a device that performs cleaning on the ejection surface formed by the nozzles of the ink ejection head 2a according to the control by the CPU 61.

[0062] The operation panel 15 is a device that accepts operations on the liquid application device 1 and displays processing results and the like by the liquid application device 1.

[0063] The head movement mechanism 23 is composed of a belt, a pulley, a motor, etc., and is a mechanism that reciprocates the carriage 2 along the rail 3 in the main scanning direction according to the control by the unit control circuit 64.

[0064] The rail movement mechanism 24 is composed of a belt, a pulley, a motor, etc., and is a mechanism that reciprocates the rail 3 on the frame 11 in the sub-scanning direction orthogonal to the main scanning direction according to the control by the unit control circuit 64. As a result, the carriage 2 supported by the rail 3 reciprocates in the sub-scanning direction.

[0065] As shown in FIG. 10, the inspection apparatus 50 includes a camera 51, a light source 52, and a control circuit 55. The camera 51 and the light source 52 are as described above.

[0066] The control circuit 55 is a control circuit for controlling the operation of the inspection apparatus 50. As shown in FIG. 10, the control circuit 55 includes a CPU 71, a memory 72, an I / F 73, an imaging I / F 74, and a light source driving circuit 75.

[0067] The CPU 71 is an arithmetic unit that comprehensively controls the operation of the inspection apparatus 50. The CPU 71 performs data communication with the memory 72, the I / F 73, the imaging I / F 74, and the light source driving circuit 75 via a bus. Further, the CPU 71 controls the imaging operation of the camera 51 via the imaging I / F 74, and controls the irradiation operation of the light source 52 via the light source driving circuit 75.

[0068] The memory 72 is a storage medium such as a ROM or a RAM that stores programs used for driving the CPU 71. Further, the memory 72 is used as a work area for the CPU 71.

[0069] The I / F 73 is an interface for data communication with the controller unit 6.

[0070] The imaging I / F 74 is an interface for data communication with the camera 51. Specifically, the imaging I / F 74 receives the captured image captured by the camera 51, and transmits a control signal regarding the imaging operation from the CPU 71 to the camera 51.

[0071] The light source driving circuit 75 is a driving circuit that causes the light source 52 to emit light according to the control of the CPU 71.

[0072] Note that the hardware configuration of the liquid application apparatus 1 shown in FIG. 10 is an example, and other constituent devices may be provided. For example, the inspection apparatus 50 may be provided with a display device that displays the inspection result of the discharge inspection operation.

[0073] (Configuration and Operation of Function Blocks of Liquid Coating Device) FIG. 11 is a diagram showing an example of the configuration of function blocks of a liquid coating device according to an embodiment. With reference to FIG. 11, the configuration and operation of the function blocks of the liquid coating device 1 according to the present embodiment will be described.

[0074] As shown in FIG. 11, the control circuit 55 of the inspection device 50 includes a communication unit 101, an inspection control unit 102, a pixel calculation unit 103, a discharge surface detection unit 104 (detection unit), a discharge command unit 105, a discharge calculation unit 106 (calculation unit), a determination unit 107, a cleaning command unit 108, an imaging control unit 109, a light source control unit 110, and a display control unit 111.

[0075] The communication unit 101 is a functional unit that performs data communication with the controller unit 6 via the I / F 73.

[0076] The inspection control unit 102 is a functional unit for controlling the discharge inspection operation in cooperation with the controller unit 6 while transmitting and receiving control signals to and from the controller unit 6 in the execution of the discharge inspection operation. For example, the inspection control unit 102 receives a start signal of the discharge inspection operation from the controller unit 6 via the communication unit 101, and transmits the inspection result of the flying state of the ink droplets to the controller unit 6 via the communication unit 101.

[0077] The pixel calculation unit 103 is a functional unit that calculates the pixel size, which is the actual distance / length corresponding to one pixel, in the captured image of the camera 51 acquired by the imaging control unit 109. Specifically, the pixel calculation unit 103 acquires, from the controller unit 6 via the communication unit 101, the amount of movement to the inspection position of the carriage 2. Next, the pixel calculation unit 103 calculates the number of pixels corresponding to the amount of movement of the carriage 2 in the captured image of the camera 51 acquired by the imaging control unit 109 based on the locus of the ejection surface of the ink ejection head 2a detected by the ejection surface detection unit 104. Then, the pixel calculation unit 103 calculates the pixel size by dividing the acquired amount of movement of the carriage 2 to the inspection position by the calculated number of pixels.

[0078] The ejection surface detection unit 104 is a functional unit that detects the position of the ejection surface of the ink ejection head 2a of the carriage 2 from the captured image captured by the camera 51 of the state where the carriage 2 moves to the inspection position, which is acquired by the imaging control unit 109. Note that the detection operation of the ejection surface is as described above.

[0079] The ejection command unit 105 is a functional unit that transmits a command signal for commanding the ejection of inspection ink droplets to the controller unit 6 via the communication unit 101. The ejection control unit 202 (to be described later) of the controller unit 6 causes the ink ejection head 2a to eject inspection ink droplets a predetermined number of times (for example, 10 times, etc.) via the unit control circuit 64 in response to the command signal.

[0080] The ejection calculation unit 106 is a functional unit that calculates the velocity, curvature, curvature comparison value for each nozzle, amount, number of droplets in one ejection signal, and presence or absence of a ligament of the ink droplets ejected from the ink ejection head 2a for inspection, using the captured image of the ink droplets ejected from the ink ejection head 2a for inspection and acquired by the imaging control unit 109, with the position of the ejection surface of the ink ejection head 2a detected by the ejection surface detection unit 104 as a reference. Further, the ejection calculation unit 106 detects the number of ejections of the ink droplets ejected from the ink ejection head 2a for inspection from the captured image. Note that the ejection calculation unit 106 may calculate at least any one of the velocity, curvature, and amount of the ink droplets with the position of the ejection surface of the ink ejection head 2a as a reference.

[0081] The determination unit 107 is a functional unit that makes a determination on the calculation result by the ejection calculation unit 106. Specifically, the determination unit 107 determines whether each of the velocity, curvature, curvature comparison value for each nozzle, amount, number of droplets in one ejection signal, and presence or absence of a ligament of the ink droplets calculated by the ejection calculation unit 106 is within the allowable range. Further, the determination unit 107 determines whether the number of ejections of the ink droplets detected by the ejection calculation unit 106 is correct. Here, the correct number of ejections is the number of ejections of the ink that the ejection control unit 202 of the controller unit 6 has commanded to the ink ejection head 2a.

[0082] The cleaning command unit 108 is a functional unit that transmits a command for cleaning the ejection surface of the ink ejection head 2a by the cleaning device 14 to the controller unit 6 via the communication unit 101.

[0083] The imaging control unit 109 is a functional unit that controls the imaging operation of the camera 51 via the imaging I / F 74.

[0084] The light source control unit 110 is a functional unit that controls the light irradiation operation of the light source 52 via the light source drive circuit 75.

[0085] The display control unit 111 is a functional unit that transmits a display command for causing the operation panel 15 to display predetermined information to the controller unit 6 via the communication unit 101.

[0086] Note that some or all of the communication unit 101, inspection control unit 102, pixel calculation unit 103, ejection surface detection unit 104, ejection command unit 105, ejection calculation unit 106, determination unit 107, cleaning command unit 108, imaging control unit 109, light source control unit 110, and display control unit 111 may be implemented by a hardware circuit (integrated circuit) such as an FPGA (Field-Programmable Gate Array) or ASIC (Application Specific Integrated Circuit), rather than a program that is software.

[0087] Also, each functional unit of the inspection device 50 shown in FIG. 11 conceptually shows the functions and is not limited to such a configuration. For example, a plurality of functional units shown as independent functional units in the inspection device 50 shown in FIG. 11 may be configured as one functional unit. On the other hand, the functions of one functional unit of the inspection device 50 shown in FIG. 11 may be divided into a plurality of functions and configured as a plurality of functional units. Further, each functional unit of the inspection device 50 does not necessarily need to be configured as a clear software module as the blocks shown in FIG. 11, and it is sufficient that the functions of each functional unit are realized as a whole when a program is executed in the inspection device 50.

[0088] As shown in FIG. 11, the controller unit 6 includes a communication unit 201, an ejection control unit 202, a movement control unit 203, and a cleaning control unit 204.

[0089] The communication unit 201 is a functional unit that performs data communication with the inspection device 50 via the I / F 63.

[0090] The ejection control unit 202 is a functional unit that controls the ink ejection operation of the ink ejection head 2a via the unit control circuit 64.

[0091] The movement control unit 203 is a functional unit that controls the reciprocating movement of the carriage 2 equipped with the ink ejection head 2a in the main scanning direction and the sub-scanning direction by controlling the head movement mechanism 23 and the rail movement mechanism 24.

[0092] The cleaning control unit 204 is a functional unit that controls the cleaning operation of the ejection surface of the ink ejection head 2a by the cleaning device 14.

[0093] Note that some or all of the communication unit 201, the ejection control unit 202, the movement control unit 203, and the cleaning control unit 204 may be realized by a hardware circuit (integrated circuit) such as an FPGA or an ASIC, rather than a program that is software.

[0094] Also, each functional unit of the controller unit 6 shown in FIG. 11 conceptually shows the functions and is not limited to such a configuration. For example, a plurality of functional units shown as independent functional units in the controller unit 6 shown in FIG. 11 may be configured as one functional unit. On the other hand, the functions of one functional unit in the controller unit 6 shown in FIG. 11 may be divided into a plurality and configured as a plurality of functional units. Further, each functional unit of the controller unit 6 does not necessarily need to be configured as a clear software module as the block shown in FIG. 11, and it is sufficient that the functions of each functional unit are realized as a whole when a program is executed in the controller unit 6.

[0095] Also, at least some or all of the inspection control unit 102, the pixel calculation unit 103, the ejection surface detection unit 104, the ejection command unit 105, the ejection calculation unit 106, the determination unit 107, the cleaning command unit 108, the imaging control unit 109, the light source control unit 110, and the display control unit 111 of the control circuit 55 may be realized by the controller unit 6.

[0096] (Discharge inspection operation of the liquid application device) FIG. 12 is a flowchart showing an example of the flow of the discharge inspection operation of the liquid application device according to the embodiment. With reference to FIG. 12, the flow of the discharge inspection operation of the liquid application device 1 according to the present embodiment will be described.

[0097] <Step S11> Before starting printing on the printing surface of the print data or the like, the controller unit 6 transmits a start signal for the discharge inspection operation for inspecting the ink droplets discharged by the ink discharge head 2a to the inspection device 50. Then, the inspection control unit 102 of the inspection device 50 receives the start signal via the communication unit 101. Thereby, the inspection device 50 enters the execution state of the discharge inspection operation. Then, the movement control unit 203 of the controller unit 6 moves the carriage 2 in the main scanning direction to an inspection position for inspecting the flying state of the ink droplets discharged from the ink discharge head 2a. Specifically, the movement control unit 203 moves the carriage 2 parallel to the discharge surface of the ink discharge head 2a to the inspection position. Further, the movement control unit 203 transmits the movement amount instructed to move the carriage 2 to the inspection position to the inspection device 50 via the communication unit 201. Then, the pixel calculation unit 103 of the inspection device 50 acquires the movement amount via the communication unit 101. Note that the movement control unit 203 may transmit the actual movement amount detected by an encoder or the like to the inspection device 50 via the communication unit 201 instead of the instructed movement amount. Then, the process proceeds to Step S12.

[0098] <Step S12> The imaging control unit 109 of the inspection device 50 causes the camera 51 to perform imaging by detecting, as a luminance difference, the state during the movement of the carriage 2 to the inspection position, and acquires the captured image. That is, the camera 51 captures a captured image by detecting a luminance difference caused by a change in the relative position between the ink ejection head 2a and the camera 51. Here, detecting a luminance difference means detecting a change in luminance (intensity). At this time, the light source control unit 110 of the inspection device 50 irradiates light from the light source 52 during the imaging by the camera 51. Then, the ejection surface detection unit 104 of the inspection device 50 detects the position of the ejection surface of the ink ejection head 2a of the carriage 2 from the captured image of the state in which the carriage 2 moves to the inspection position, which is acquired by the imaging control unit 109. In the example shown in FIG. 12, the detection of the position of the ejection surface of the ink ejection head 2a by the ejection surface detection unit 104 is assumed to be performed before the ejection of the inspection ink droplets, but it is not limited thereto, and it may be performed after the ejection of the inspection ink droplets. Then, the process proceeds to step S13.

[0099] <Step S13> The pixel calculation unit 103 calculates the pixel size, which is the actual distance / length corresponding to one pixel, in the captured image of the camera 51 acquired by the imaging control unit 109. Specifically, the pixel calculation unit 103 calculates the number of pixels corresponding to the movement amount of the carriage 2 in the captured image of the camera 51 acquired by the imaging control unit 109 based on the locus of the ejection surface of the ink ejection head 2a detected by the ejection surface detection unit 104. Then, the pixel calculation unit 103 calculates the pixel size by dividing the acquired movement amount of the carriage 2 to the inspection position by the calculated number of pixels. Note that the pixel size may be calculated in advance by the pixel calculation unit 103. Then, the process proceeds to step S14.

[0100] <Step S14> The ejection command unit 105 of the inspection device 50 transmits a command signal for commanding the ejection of inspection ink droplets to the controller unit 6 via the communication unit 101. The ejection control unit 202 of the controller unit 6 ejects the number of ink droplets for inspection from the ink ejection head 2a of the carriage 2 stopped at the inspection position in accordance with the command signal received by the communication unit 201. Further, the imaging control unit 109 causes the camera 51 to image the ejection state of the ink droplets from the ink ejection head 2a and acquires the captured image. At this time, the light source control unit 110 of the inspection device 50 irradiates light from the light source 52 during the imaging by the camera 51. Then, the process proceeds to step S15.

[0101] <Step S15> The ejection arithmetic unit 106 of the inspection device 50 uses the captured image obtained by the imaging control unit 109 and capturing the ink droplets ejected from the ink ejection head 2a for inspection, and based on the position of the ejection surface of the ink ejection head 2a detected by the ejection surface detection unit 104, calculates the speed, bend, bend comparison value for each nozzle, amount, number of droplets in one ejection signal, and the presence or absence of a ligament of the ink droplets. Then, the process proceeds to step S16.

[0102] <Step S16> Also, the ejection arithmetic unit 106 detects the number of ejections of the ink droplets ejected from the ink ejection head 2a for inspection from the captured image. Then, the process proceeds to step S17.

[0103] <Step S17> The determination unit 107 of the inspection device 50 determines whether the speed, bend, and amount of the ink droplets calculated by the ejection arithmetic unit 106 are within the allowable range. If all of the speed, bend, bend comparison value for each nozzle, amount, number of droplets in one ejection signal, and the presence or absence of a ligament of the ink droplets are within the allowable range (step S17: Yes), the process proceeds to step S18. If at least one of them is outside the allowable range (step S17: No), the process proceeds to step S20.

[0104] <Step S18> Furthermore, the determination unit 107 determines whether the number of ejected ink droplets detected by the ejection calculation unit 106 is correct. If the number of ejections is correct (step S18: Yes), the process proceeds to step S19. If the number of ejections is incorrect (step S18: No), the process proceeds to step S20.

[0105] <Step S19> The inspection control unit 102 transmits, via the communication unit 101, to the controller unit 6 that the inspection result of the flying state of the ink droplets is OK. When the controller unit 6 receives that it is OK, it proceeds to the printing process on the printing surface of the print data. Then, the ejection inspection operation ends.

[0106] <Step S20> Furthermore, the determination unit 107 determines whether the number of cleaning operations by the cleaning device 14 in the ejection inspection operation is within a predetermined number of times (for example, 3 times). If the number of cleaning operations is within the predetermined number of times (step S20: Yes), the process proceeds to step S22. If it exceeds the predetermined number of times (step S20: No), the process proceeds to step S21.

[0107] <Step S21> The inspection control unit 102 transmits, via the communication unit 101, to the controller unit 6 that the inspection result of the flying state of the ink droplets is NG ("Determination NG" in FIG. 12). Then, the controller unit 6 causes the operation panel 15 to display that the inspection result is NG. Note that the display control unit 111 of the inspection device 50 may cause the operation panel 15 to display that the inspection result is NG. Then, the ejection inspection operation ends.

[0108] <Step S22> The cleaning instruction unit 108 of the inspection device 50 transmits an instruction for cleaning the ejection surface of the ink ejection head 2a by the cleaning device 14 to the controller unit 6 via the communication unit 101. Then, the cleaning control unit 204 of the controller unit 6 causes the cleaning device 14 to clean the ink ejection head 2a according to the received cleaning instruction, and then returns to step S11.

[0109] As described above, in the inspection device 50 according to the present embodiment, the camera 51 captures an image by detecting the flying state of the liquid ejected from the ink ejection head 2a as a luminance difference, and the ejection surface detection unit 104 changes the relative position between the ink ejection head 2a and the camera 51 to detect the position of the ejection surface of the ink ejection head 2a in the captured image where the luminance difference is detected by the camera 51. Thereby, the calculation load can be reduced, the increase in size of the inspection device 50 and the liquid application device 1 can be suppressed, and the ejection surface of the ink ejection head 2a can be detected.

[0110] In the above-described embodiment, the configuration applied to the inspection device 50 for the liquid application device 1 that performs printing on a printing surface such as a road or a wall has been described, but the present invention is not limited thereto. For example, the liquid application device 1 may be an inkjet printing device that performs printing on a normal paper medium or the like. Also, in the production process of the liquid application device 1, it is possible to use the inspection device 50 to inspect the flying state of the ink droplets of the ink ejection head.

[0111] (Modification 1) Regarding the liquid application device 1 according to Modification 1 of the present embodiment, the description will be centered on the differences from the liquid application device 1 according to the present embodiment.

[0112] FIG. 13 is a diagram showing an example of the configuration of an inspection device according to Modification 1 of the embodiment. With reference to FIG. 13, the configuration of the liquid application device 1 and the inspection device 50 according to this modification will be described.

[0113] As shown in FIG. 13, the liquid application device 1 according to this modification further includes a vertical rail 16. Note that the other configurations of the liquid application device 1 according to this modification are the same as those of the liquid application device 1 according to the above-described embodiment.

[0114] The vertical rail 16 is a rail member that is supported by the rail 3 and supports the carriage 2 so as to be movable in the height direction (arrow C shown in FIG. 13). That is, the carriage 2 moves in the main scanning direction when the vertical rail 16 is moved in the main scanning direction (arrow A shown in FIG. 13) by the head movement mechanism 23. As a result, the movement control unit 203 can reciprocate the carriage 2 on which the ink ejection head 2a is mounted in the height direction. The movement in the height direction is performed, for example, to make the distance from the ink ejection head 2a to the arrival point of the ink droplets constant when the printing surface is not flat but has irregularities or inclinations.

[0115] In this modification, when the ejection surface detection unit 104 detects the position of the ejection surface of the ink ejection head 2a, the movement control unit 203 moves the carriage 2 in the height direction (that is, the direction perpendicular to the ejection surface). That is, in this case, the camera 51 captures an image by detecting a luminance difference caused by a change in the relative position between the ink ejection head 2a and the camera 51. Note that the movement direction perpendicular to the ejection surface of the ink ejection head 2a is an example of the "predetermined one direction" of the present invention. Also in this case, the position of the ejection surface of the ink ejection head 2a can be detected as an edge that causes a luminance difference, and based on this position, it is possible to calculate the speed and bending of the ink droplets.

[0116] (Modification 2) The liquid application device 1 according to Modification 2 of the present embodiment will be described centering on the points different from the liquid application device 1 according to the present embodiment.

[0117] FIG. 14 is a diagram showing an example of the configuration of an inspection device according to Modification 2 of the embodiment. The configuration of the inspection device 50a according to this modification will be described with reference to FIG. 14.

[0118] The camera 51 of the inspection apparatus 50a according to this modification example can move, for example, as shown in FIG. 14, in the main scanning direction (arrow A shown in FIG. 14) and the height direction (arrow C shown in FIG. 14). In this case, the camera 51 is moved in the main scanning direction and the height direction by a drive mechanism (not shown).

[0119] In the ejection inspection operation, instead of the imaging control unit 109 causing the camera 51 to image the state during the movement of the carriage 2 to the inspection position as in the above-described embodiment, in this modification example, while the camera 51 moves in a direction parallel or perpendicular to the ejection surface of the ink ejection head 2a, the imaging control unit 109 causes the camera 51 to image. That is, in this case, the camera 51 captures an imaging image by detecting a luminance difference caused by a change in the relative position between the ink ejection head 2a and the camera 51. As a result, the position of the ejection surface of the ink ejection head 2a can be detected as an edge that causes a luminance difference, and based on this position, it becomes possible to calculate the speed and bending of the ink droplets, etc. Note that the operation of the other liquid application apparatus 1 is the same as that of the above-described embodiment.

[0120] (Modification Example 3) Regarding the liquid application apparatus 1 according to Modification Example 3 of the present embodiment, the description will focus on the points that differ from the liquid application apparatus 1 according to the present embodiment.

[0121] FIG. 15 is a diagram showing an example of the configuration of an inspection apparatus according to Modification Example 3 of the embodiment. The configuration of the inspection apparatus 50b according to this modification example will be described with reference to FIG. 15.

[0122] The camera 51 of the inspection apparatus 50b according to this modification example can rotate, for example, as shown in FIG. 15, along a plane parallel to the ejection surface of the ink ejection head 2a, with the ink ejection direction of the ink ejection head 2a of the carriage 2 as the central axis. In this case, the camera 51 is rotationally moved by a drive mechanism (not shown).

[0123] During the ejection inspection operation, instead of the imaging control unit 109 causing the camera 51 to capture images of the carriage 2 moving to the inspection position as in the above-described embodiment, in this modified example, the imaging control unit 109 causes the camera 51 to capture images while the camera 51 rotates along a plane parallel to the ejection surface of the ink ejection head 2a, with the ink ejection direction of the ink ejection head 2a as its central axis. That is, in this case, the camera 51 captures an image by detecting a brightness difference caused by a change in the relative position between the ink ejection head 2a and the camera 51. This makes it possible to detect the position of the ejection surface of the ink ejection head 2a as an edge that generates a brightness difference, and it is possible to calculate the speed and curvature of the ink droplets based on that position. Note that other operations of the liquid application device 1 are the same as those in the above-described embodiment.

[0124] (Variation 4) The liquid application apparatus 1 according to the fourth modification of the present embodiment will be described, focusing on the differences from the liquid application apparatus 1 according to the present embodiment.

[0125] 16 is a diagram illustrating the light emitting operation of the light source in the inspection device according to the fourth modification of the embodiment. The operation of the inspection device 50 according to this modification will be described with reference to FIG.

[0126] In this modification, when detecting the position of the ejection surface of the ink ejection head 2a, the light source control unit 110 of the inspection device 50 causes the light source 52 to emit light at a predetermined lighting ratio (for example, 25%) via the light source drive circuit 75, as shown in Fig. 16. This makes it possible to detect the position of the ejection surface of the ink ejection head 2a as an edge due to the difference in brightness between when the light source 52 is on and when it is off, and it becomes possible to calculate the speed and curvature of the ink droplets based on this position. Note that other operations of the liquid application device 1 are the same as those of the above-described embodiment.

[0127] (Variation 5) The liquid application apparatus 1 according to the fifth modification of the present embodiment will be described, focusing on the differences from the liquid application apparatus 1 according to the present embodiment.

[0128] FIG. 17 is a diagram showing an example of the configuration of an inspection apparatus according to Modification 5 of the embodiment. With reference to FIG. 17, the configuration of the inspection apparatus 50c according to this modification will be described.

[0129] The camera 51 of the inspection apparatus 50c according to this modification is, for example, as shown in FIG. 17, capable of vibrating.

[0130] In the ejection inspection operation, instead of the imaging control unit 109 causing the camera 51 to image the state of the carriage 2 during movement to the inspection position as in the above-described embodiment, in this modification, the imaging control unit 109 causes the camera 51 to image while the camera 51 vibrates. That is, in this case, the camera 51 captures an imaging image by detecting a luminance difference caused by a change in the relative position between the ink ejection head 2a and the camera 51 due to vibration. As a result, the position of the ejection surface of the ink ejection head 2a can be detected as an edge by generating a luminance difference due to vibration, and based on this position, it becomes possible to calculate the speed and curvature of the ink droplets. Note that the operations of the other liquid application apparatuses 1 are the same as those in the above-described embodiment.

[0131] In the above-described embodiment and each modification, when at least one of the functions of the liquid coating apparatus 1 and the inspection apparatus 50, 50a-50c is realized by executing a program, the program is provided in advance in a ROM or the like. Furthermore, in the above-described embodiment and each modification, the program executed by the liquid coating apparatus 1 and the inspection apparatus 50, 50a-50c may be provided by being recorded in an installable or executable file format on a computer-readable recording medium such as a CD-ROM (Compact Disc Read Only Memory), a flexible disk (FD), a CD-R (Compact Disk-Recordable), or a DVD (Digital Versatile Disc). Furthermore, in the above-described embodiment and each modification, the program executed by the liquid coating apparatus 1 and the inspection apparatus 50, 50a-50c may be stored on a computer connected to a network such as the Internet and downloaded via the network. Furthermore, in the above-described embodiment and each modification, the program executed by the liquid coating apparatus 1 and the inspection apparatus 50, 50a-50c may be provided or distributed via a network such as the Internet. Furthermore, in the above-described embodiments and variations, the programs executed by the liquid application device 1 and the inspection devices 50, 50a to 50c are modularly structured to include at least one of the functional units described above, and in actual hardware, the CPU reads and executes the programs from the above-described storage devices, thereby loading and generating the above-described functional units onto the main storage device.

[0132] The aspects of the present invention are as follows. <1> An inspection device that inspects the ejection state of liquid ejected from an ejection head having one or more nozzles of a liquid ejection device, an imaging device that captures an image by detecting a discharge state of the liquid discharged from the discharge head as a change in brightness; a detection unit that detects the position of the ejection surface of the ejection head in a captured image in which a luminance change is detected by the imaging device by changing the relative position between the ejection head and the imaging device; This is an inspection device equipped with the above. <2> a calculation unit that calculates at least one of the speed, deflection, deflection comparison value for each nozzle, amount, number of droplets per ejection signal, and presence or absence of ligaments of droplets ejected from the ejection head using an image captured by the imaging device in the ejection state and the position of the ejection surface detected by the detection unit as a reference. <1> The inspection device is described in <3> The detection unit detects the position of the ejection surface at the same timing as the ejection of liquid from the ejection head. <2> The inspection device is described in <4> the ejection head is movable in at least one predetermined direction; the detection unit detects the position of the ejection surface in an image captured by the imaging device while the ejection head is moving in the one direction. <1> ~ <3> 10. The inspection device according to claim 9, wherein: <5> the ejection head is movable parallel to the ejection surface, The detection unit detects the position of the ejection surface in an image captured by the imaging device while the ejection head is moving parallel to the ejection surface. <4> 2 is an inspection device according to the first embodiment. <6> the ejection head is movable perpendicular to the ejection surface; The detection unit detects the position of the ejection surface in an image captured by the imaging device while the ejection head is moving perpendicular to the ejection surface. <4> 2 is an inspection device according to the first embodiment. <7> the imaging device is movable in at least one predetermined direction; the detection unit detects the position of the ejection surface in an image captured by the imaging device while the imaging device is moving in the one direction. <1> ~ <3> 10. The inspection device according to claim 9, wherein: <8> the imaging device is capable of rotationally moving along a plane parallel to the ejection surface, with the ejection direction of the liquid from the ejection head as a central axis; The detection unit detects the position of the ejection surface in an image captured by the imaging device while the imaging device is rotating. <1> ~ <3> 10. The inspection device according to claim 9, wherein: <9> the imaging device is capable of vibrating; The detection unit detects the position of the ejection surface in an image captured by the imaging device while the imaging device is vibrating. <1> ~ <3> 10. The inspection device according to claim 9, wherein: <10> a light source that faces the imaging device and is disposed on the opposite side of the ejection head from the imaging device when the ejection head is imaged by the imaging device; The light source emits light when an image is captured by the imaging device. <1> ~ <9> 10. The inspection device according to claim 9, wherein: <11> The light source irradiates light at a predetermined lighting ratio when an image is captured by the imaging device for detecting the position of the ejection surface by the detection unit. <10> 2 is an inspection device according to the first embodiment. <12> The imaging device captures an image through a telecentric lens. <1> ~ <11> 10. The inspection device according to claim 9, wherein: <13> The method further includes a discharge receiver fixed to a position directly below the discharge head when the discharge state of the liquid discharged from the discharge head is inspected. <1> ~ <12> 10. The inspection device according to claim 9, wherein: <14> the ejection head for ejecting liquid; The aforementioned <1> ~ <13> an inspection device according to any one of the preceding claims; The liquid ejection device is provided with: [Explanation of symbols]

[0133] 1 Liquid application device 2 carriages 2a Ink ejection head 3 Rail 4 Ink supply system 4a Pipe 5 Power Supply System 6 Controller Unit 7 Three-Dimensional Camera 8 Two-Dimensional Camera 9 GNSS Receiver 10 Tire 11 Frame 12 Structure 13 Maintenance Section 14 Cleaning Device 15 Operation Panel 16 Vertical Rail 21 Printing Unit 22 Control Unit 23 Head Movement Mechanism 24 Rail Movement Mechanism 50, 50a - 50c Inspection Device 51 Camera 51a Optical System 52 Light Source 53 Air Ejection Receiver 54 Frame 55 Control Circuit 61 CPU 62 Memory 63 I / F 64 Unit Control Circuit 71 CPU 72 Memory 73 I / F 74 Imaging I / F 75 Light Source Drive Circuit 101 Communication Section 102 Inspection Control Section 103 Pixel Calculation Section 104 Ejection Surface Detection Section 105 Ejection Command Section 106 Ejection Calculation Section 107 Judgment Section 108 Cleaning Command Section 109 Imaging Control Section 110 Light Source Control Section 111 Display Control Section 201 Communication Section 202 Ejection Control Section 203 Movement Control Section 204 Cleaning control unit BIM1~BIM3 captured images PAR print area [Prior art documents] [Patent documents]

[0134] [Patent Document 1] Japanese Patent Application Publication No. 10-206624

Claims

1. An inspection device for inspecting the ejection state of a liquid ejected from a ejection head having one or more nozzles of a liquid ejection device, comprising: an imaging device that images by detecting the ejection state of the liquid ejected from the ejection head as a luminance change; a detection unit that detects the position of the ejection surface of the ejection head in an imaging image in which a luminance change is detected by the imaging device by changing the relative position between the ejection head and the imaging device; An inspection device comprising:

2. Using the imaging image captured by the imaging device for the ejection state, based on the position of the ejection surface detected by the detection unit, at least one of the speed, bend, bend comparison value for each nozzle, amount, number of droplets in one ejection signal, and presence or absence of a ligament of the droplets ejected from the ejection head A calculation unit for calculating, further comprising the inspection device according to claim 1.

3. The inspection device according to claim 2, wherein the detection unit detects the position of the ejection surface at the same timing as the ejection of the liquid from the ejection head.

4. The ejection head is movable at least in a predetermined one direction, The inspection device according to any one of claims 1 to 3, wherein the detection unit detects the position of the ejection surface in an imaging image captured by the imaging device while the ejection head is moving in the one direction.

5. The ejection head is movable parallel to the ejection surface, The inspection device according to claim 4, wherein the detection unit detects the position of the ejection surface in an imaging image captured by the imaging device while the ejection head is moving parallel to the ejection surface.

6. The ejection head is movable perpendicular to the ejection surface, The inspection device according to claim 4, wherein the detection unit detects the position of the ejection surface in an imaging image captured by the imaging device while the ejection head is moving perpendicular to the ejection surface.

7. The imaging device is movable at least in a predetermined one direction, The inspection device according to any one of claims 1 to 3, wherein the detection unit detects the position of the ejection surface in an imaging image captured by the imaging device while the imaging device is moving in the one direction.

8. The imaging device is capable of rotational movement around the liquid ejection direction of the ejection head as a central axis along a plane parallel to the ejection surface. The inspection device according to any one of claims 1 to 3, wherein the detection unit detects the position of the ejection surface in a captured image captured by the imaging device while the imaging device is rotationally moving.

9. The imaging device is vibratable, The inspection device according to any one of claims 1 to 3, wherein the detection unit detects the position of the ejection surface in a captured image captured by the imaging device while the imaging device is vibrating.

10. The inspection device further includes a light source that faces the imaging device and is disposed on the side opposite to the imaging device with respect to the ejection head when the ejection head is imaged by the imaging device, The inspection device according to any one of claims 1 to 3, wherein the light source irradiates light when imaged by the imaging device.

11. The inspection device according to claim 10, wherein the light source irradiates light at a predetermined lighting ratio when imaged by the imaging device for detecting the position of the ejection surface by the detection unit.

12. The inspection device according to any one of claims 1 to 3, wherein the imaging device images through a telecentric lens.

13. The inspection device according to any one of claims 1 to 3, further comprising a discharge receiver fixed at a position directly below the discharge head when the discharge state of the liquid discharged from the discharge head is inspected.

14. The liquid and the discharge head for discharging the liquid, The inspection device according to any one of claims 1 to 3, A liquid discharge device comprising the same.

Images