Nozzle position adjusting device, nozzle position adjusting method and program

Abstract

To provide a nozzle position adjusting device that can adjust a position of a nozzle with high accuracy, while stably and efficiently manufacturing an inkjet head.SOLUTION: A nozzle position adjusting device is provided with: a transparent body arranged to oppose to a nozzle surface of an inkjet head having a plurality of nozzles, in which marks are formed at predetermined positions thereof; a photographing device that individually photographs mark images including the marks with a focus put on the mark and nozzle images including the nozzles with a focus put on the nozzles; and a control part that moves the inkjet head so that the marks fit to the nozzles, on the basis of the mark images and the nozzle images.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present disclosure relates to an apparatus, a method, and a program for adjusting a nozzle position of an inkjet head. [Background technology]

[0002] Conventionally, there is known an inkjet image forming apparatus that ejects ink from a plurality of nozzles arranged in an inkjet head onto a recording medium such as paper to form an image on the recording medium. In order to form an image with high precision in an inkjet image forming apparatus, it is necessary to position the plurality of nozzles with high precision. Therefore, in recent years, various methods for positioning the plurality of nozzles with high precision have been proposed.

[0003] For example, Patent Document 1 discloses an inkjet head assembly device that adjusts the position of the head part based on an image of the head part. The assembly device acquires an image of the head part and detects the position of the nozzle from the acquired image of the head part. The assembly device then moves the head part so that the detected nozzle position coincides with a predetermined target position.

[0004] For example, Patent Document 2 discloses an inkjet recording device that aligns a nozzle head using a plate on which an alignment mark is formed. The inkjet recording device simultaneously captures an image of the nozzle head and a transparent plate on which an alignment mark is formed and which is disposed opposite the nozzle head. The inkjet recording device then aligns the nozzles of the nozzle head or the nozzle marks formed on the nozzle head so that they coincide with the alignment mark based on the alignment mark. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 3831936 [Patent Document 2] Patent No. 4195986 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the assembly device described in Patent Document 1, the camera and lens that capture the image of the head and detect the nozzle position may detect a position different from the actual position of the head due to vibrations generated by the equipment driving parts, temperature changes, etc. When the detection position is shifted, even if the detected position matches the target position, the actual position of the head will not match the target position. Therefore, during the manufacture of the inkjet head, it is necessary to adjust the detection position shift using a prototype on which the target position is recorded, which causes a problem that efficient manufacture of the inkjet head is difficult.

[0007] In addition, in the method described in Patent Document 2, in order to focus on both the nozzle and the alignment mark and perform nozzle alignment with high resolution and high precision, it is necessary to increase the magnification of the lens when capturing an image. However, when the magnification of the lens is increased, the depth of field becomes shallow, so that it is required to manufacture the inkjet head with a narrow focusing range of the lens. In this case, the distance between the nozzle head and the transparent plate needs to be very short, and there is a possibility that they will collide with each other and the nozzle head will be damaged. Therefore, there is a problem that it is difficult to stably manufacture the inkjet head.

[0008] The present disclosure has been made in consideration of the problems in the conventional technology described above, and aims to provide a nozzle position adjustment device, a nozzle position adjustment method, and a program that are capable of adjusting the nozzle position with high precision while stably and efficiently manufacturing inkjet heads. [Means for solving the problem]

[0009] The nozzle position adjustment device according to the present disclosure comprises: a transparent body disposed opposite a nozzle surface of an inkjet head having a plurality of nozzles and having marks formed at predetermined positions; an imaging device that captures a mark image including the mark in a state focused on the mark, and a nozzle image including the nozzle in a state focused on the nozzle; a control unit that moves the inkjet head based on the mark image and the nozzle image so that the mark and the nozzle are aligned; Equipped with.

[0010] Further, the nozzle position adjustment method according to the present disclosure includes: capturing a mark image including a mark formed at a predetermined position on a transparent body arranged opposite a nozzle surface of an inkjet head having a plurality of nozzles, while focusing on the mark; capturing a nozzle image including the nozzle while focusing on the nozzle; Based on the mark image and the nozzle image, the inkjet head is moved so that the mark and the nozzle are aligned.

[0011] Furthermore, the program according to the present disclosure includes: The above nozzle position adjustment method is executed by a computer. Effect of the Invention

[0012] According to the present disclosure, it is possible to stably and efficiently manufacture inkjet heads while adjusting nozzle positions with high precision. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a schematic diagram showing an example of the configuration of an inkjet printer equipped with an inkjet head whose nozzle position is adjusted by a nozzle position adjustment device according to the first embodiment. [Diagram 2] FIG. 2 is a block diagram showing the main components of a control system of the inkjet printer of FIG. [Diagram 3]FIG. 3 is a diagram showing a schematic arrangement of inkjet heads in a head module of the inkjet printer of FIG. [Figure 4] FIG. 4 is a perspective view showing an example of the appearance of the inkjet head of FIG. [Diagram 5] FIG. 5 is a schematic cross-sectional view showing an example of the configuration of the nozzle position adjusting device according to the first embodiment. [Figure 6] FIG. 6 is a block diagram showing a main part of a control system of the nozzle position adjusting device of FIG. [Figure 7] FIG. 7 is a functional block diagram showing an example of the configuration of the control unit in FIG. [Figure 8] FIG. 8 is a schematic cross-sectional view showing a state in which the camera unit is focused on a mark in the nozzle position adjustment device 1 of FIG. [Figure 9] FIG. 9 is a schematic diagram showing an example of a mark image. [Figure 10] FIG. 10 is a schematic diagram for explaining irradiation of light by coaxial illumination when capturing an image of a mark. [Figure 11] FIG. 11 is a schematic cross-sectional view showing a state in which a camera unit is focused on a nozzle in the nozzle position adjustment device of FIG. [Figure 12] FIG. 12 is a schematic diagram showing an example of a nozzle image. [Figure 13] FIG. 13 is a schematic diagram for explaining irradiation of light by the ring illumination when imaging the nozzle. [Figure 14] FIG. 14 is a schematic diagram showing an example of a composite image. [Figure 15] FIG. 15 is a schematic diagram for explaining the identification of the endmost nozzle. [Figure 16] FIG. 16 is a flowchart showing an example of the flow of a nozzle position adjustment process performed by the nozzle position adjustment device according to the first embodiment. [Figure 17] FIG. 17 is a schematic diagram showing an example of an arrangement of a plurality of heads in a head module according to the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. The present disclosure is not limited to the following embodiments, and various modifications are possible without departing from the spirit of the present disclosure. In addition, in each drawing, the same reference numerals are used to denote the same or equivalent parts, and this is common throughout the entire specification.

[0015] <Embodiment 1> A first embodiment of the present disclosure will be described with reference to the drawings. The nozzle position adjustment device according to the first embodiment is a device for adjusting the nozzle position of an inkjet head that is applied to an image forming device such as an inkjet printer that forms an image by ejecting ink droplets onto a recording medium such as paper.

[0016] Before describing the nozzle position adjusting device according to the first embodiment, the configuration of an inkjet printer as an image forming apparatus and an inkjet head will be described below.

[0017] [Configuration of the inkjet printer 100] Fig. 1 is a schematic diagram showing an example of the configuration of an inkjet printer 100 equipped with an inkjet head 155 whose nozzle positions are adjusted by the nozzle position adjustment device according to the embodiment 1. Fig. 2 is a block diagram showing the main parts of a control system of the inkjet printer 100 of Fig. 1.

[0018] As shown in Figures 1 and 2, the inkjet printer 100 includes a transport section 110, a supply section 120, a discharge section 130, an ink supply section 140, a drawing section 150, a reading section 160, an operation display section 170, an input / output interface 180, and a control section 190.

[0019] The transport unit 110 has a plurality of members related to transport, such as a transport belt 111, a driving roller 112, and a driven roller 113. The transport unit 110 transports the recording medium M by the transport operation of the plurality of members, such as the transport belt 111. Specifically, in the transport unit 110, the transport belt 111 is stretched around the driving roller 112 and the driven roller 113, and is driven by driving the driving roller 112 to rotate. As a result, the recording medium M supplied from the supply unit 120 is transported to the drawing unit 150 while being placed on the transport surface 111a of the transport belt 111, and is transported to the discharge unit 130 after drawing (also referred to as image formation or printing) in the drawing unit 150.

[0020] The recording medium M may be any of various media capable of fixing the ink ejected from the inkjet head 155 described later. The recording medium M may be, for example, a sheet-shaped medium such as paper, cloth (fabric), or resin. The recording medium M is not limited to a sheet-shaped medium, and may be a roll-shaped medium such as paper, cloth, or resin. An example of the resin recording medium M is a PCB (Printed Circuit Board) substrate. When the recording medium M is a PCB (Printed Circuit Board) substrate, drawing by the inkjet printer 100 can be applied to printing solder resist or marking ink on the PCB substrate. Other examples of the recording medium M that may be drawn include the metallic body of an automobile, building materials (exterior walls, roofing materials, tiles, etc.), and cans (metal cans for storing food, beverages, etc.). When the recording medium M is various building materials or various metal products, drawing by the inkjet printer 100 can be applied to painting on the various building materials or various metal products.

[0021] Further, as an example here, the conveying unit 110 that conveys the recording medium M by the conveying belt 111 is illustrated, but the conveying unit 110 is not limited to the conveying belt 111 and may be configured to convey the recording medium M by a drum or roller.

[0022] The supply section 120 has a supply stacking section 121 and a supply conveying section 122. The supply stacking section 121 stacks and stores a plurality of recording media M. The supply conveying section 122 conveys and supplies the recording media M from the supply stacking section 121 to the conveying section 110. The supply stacking section 121 is configured to be able to rise and fall, and when the topmost recording medium M is conveyed to the conveying section 110 by the supply conveying section 122, the supply stacking section 121 rises so that the recording medium M that has become the topmost after the conveying can be conveyed to the supply conveying section 122.

[0023] The discharge section 130 has a discharge stacking section 131 and a discharge conveying section 132. The discharge stacking section 131 stacks and stores a plurality of recording media M. The discharge conveying section 132 conveys the recording media M discharged from the conveying section 110 to the discharge stacking section 131. The discharge stacking section 131 is configured to be capable of rising and lowering, and when the recording media M is conveyed from the discharge conveying section 132 to the discharge stacking section 131, the discharge stacking section 131 descends.

[0024] The supply conveying section 122 and the discharge conveying section 132 each have, for example, a plurality of rollers, and convey the recording medium M by rotating the rollers. The supply conveying section 122 and the discharge conveying section 132 are not limited to rollers, and may be configured with a belt, or may be configured with a combination of rollers and belts.

[0025] When a roll-shaped medium is used as the recording medium M, an unwinding roller on which the roll-shaped medium is stored in a wound state is used instead of the supply stacking unit 121. In this case, a winding roller that winds up the roll-shaped medium is used instead of the discharge stacking unit 131. The roll-shaped medium is transported to the transport unit 110 by rotating the unwinding roller, and is wound up by the winding roller by rotating the winding roller.

[0026] A post-processing device may be provided between the conveying unit 110 and the discharging unit 130 to perform post-processing on the recording medium M on which an image is formed by the drawing unit 150. One example of the post-processing device is a fixing device that fixes ink to the recording medium M. When, for example, an ultraviolet-curable ink is used as the ink, a fixing device is used that irradiates the recording medium M with ultraviolet rays to fix the ink to the recording medium M. When, for example, an aqueous ink or a solvent ink is used as the ink, a fixing device is used that fixes the ink to the recording medium M by a method such as drying. As the post-processing device, a device other than the fixing device, for example, a cutting device that cuts the recording medium M to a desired length, may be used.

[0027] The configurations of the transport section 110, the supply section 120, and the discharge section 130 can be modified in various ways depending on the type of recording medium M to be imaged.

[0028] The ink supply unit 140 is a device that supplies ink to a first sub-tank 152a of the drawing unit 150, which will be described later. The ink supply unit 140 has a main tank 141 and components (e.g., a pump and a valve) related to the supply of ink, which are not shown. The main tank 141 stores ink to be supplied to the first sub-tank 152a at room temperature. The ink supply unit 140 supplies ink from the main tank 141 to the first sub-tank 152a via a flow path 142 using a pump or the like (not shown).

[0029] The heating unit 195 is disposed upstream of the drawing unit 150 in the transport direction T of the recording medium M, and heats the recording medium M transported by the transport belt 111 to a predetermined temperature. The heating unit 195 is connected to the control unit 190 (see FIG. 2) and is controlled by the control unit 190.

[0030] For example, the heating unit 195 has an infrared heater or the like, and when power is supplied to the infrared heater based on a control signal supplied from the control unit 190, the infrared heater is caused to generate heat and heat the recording medium M to a predetermined temperature. Note that depending on the type of ink used, the provision of the heating unit 195 may not be necessary.

[0031] Here, the heating section 195 is disposed on the upper surface side of the conveyor belt 111, but instead of (or in addition to) the heating section 195, a heating section may be provided on the lower surface side of the conveyor belt 111, and the conveyor belt 111 may be heated to heat the recording medium M.

[0032] The drawing unit 150 has a carriage 151, a first sub-tank 152a, a second sub-tank 152b, flow paths 153a, 153b and 153c, a head driving unit 154, and an inkjet head (hereinafter simply referred to as the head) 155 (see FIGS. 1 and 2).

[0033] 1, for the sake of simplicity, ink supply units 140 and drawing units 150 for one color are shown, but the ink supply units 140 and drawing units 150 are arranged according to the number of colors to be used. For example, when four colors, yellow (Y), magenta (M), cyan (C), and black (K), are used, ink supply units 140 and drawing units 150 for four colors are arranged, and the drawing units 150 are arranged so as to be lined up at predetermined intervals along the transport direction T.

[0034] Further, a plurality of second sub-tanks 152b and heads 155 are connected to the downstream side of the first sub-tank 152a, but in FIG. 1, only one of each is shown for the sake of simplicity.

[0035] The carriage 151 is a housing that holds inside it a first sub-tank 152a, a second sub-tank 152b, flow paths 153a, 153b, and 153c, a head drive unit 154, a head 155, and devices and members necessary for image formation.

[0036] The first sub-tank 152a is connected to the downstream side of the main tank 141. The first sub-tank 152a stores ink supplied from the main tank 141 in the carriage 151. The ink in the first sub-tank 152a is supplied to the second sub-tank 152b via a flow path 153a using a pump or the like (not shown) in the carriage 151.

[0037] A plurality of second sub-tanks 152b are connected to the downstream side of the first sub-tank 152a. The second sub-tank 152b stores the ink supplied from the first sub-tank 152a in the carriage 151. The ink in the second sub-tank 152b is supplied to a manifold 156 of the head 155 (described later) via a flow path 153b using a pump or the like (not shown) in the carriage 151. A portion of the ink supplied to the manifold 156 is returned (recovered) to the second sub-tank 152b via a flow path 153c, and can be re-supplied to the manifold 156. That is, the ink circulates between the second sub-tank 152b and the manifold 156 via the flow paths 153b and 153c.

[0038] Based on the control of a control unit 190 (described later), the head driving unit 154 outputs a driving voltage corresponding to the image data of the image to be formed to a piezoelectric element 158 ​​of a head 155 (described later). The driving voltage from the head driving unit 154 drives the piezoelectric element 158, and an amount of ink corresponding to the image data is ejected from a nozzle 159 of the head 155 (described later).

[0039] A plurality of heads 155 are connected to the downstream sides of the plurality of second sub-tanks 152b, respectively. That is, a plurality of second sub-tanks 152b and heads 155 are connected to the downstream sides of the first sub-tanks 152a.

[0040] The head 155 has a manifold 156, individual supply channels 157, piezoelectric elements 158, and nozzles 159. The head 155 has a plurality of nozzles 159, and the individual supply channels 157 and piezoelectric elements 158 are provided in accordance with the number of nozzles 159.

[0041] The manifold 156 communicates with a plurality of individual supply channels 157, and ink supplied to the manifold 156 is supplied to the individual supply channels 157. A part or the whole of the individual supply channel 157 is a chamber having an internal space capable of temporarily storing ink ejected from the nozzle 159. A piezoelectric element 158 ​​is provided on the wall surface of the individual supply channel 157. Moreover, one end of the nozzle 159 communicates with the individual supply channel 157, and the other end is an open end.

[0042] A driving voltage is applied to the piezoelectric element 158 ​​from the head driving unit 154. When the driving voltage from the head driving unit 154 is applied to the piezoelectric element 158, the piezoelectric element 158 ​​deforms in response to the applied driving voltage, and the individual supply flow path 157 deforms. Then, due to the deformation of the individual supply flow path 157, the pressure on the ink in the individual supply flow path 157 that is supplied to the nozzle 159 changes.

[0043] Therefore, when a drive voltage from the head drive unit 154 is applied to the piezoelectric element 158, the piezoelectric element 158 ​​and the individual supply flow path 157 are deformed, causing a pressure change to occur in the ink in the individual supply flow path 157. As a result, the ink in the individual supply flow path 157 is ejected from the nozzle 159. In this manner, an image is formed on the recording medium M by ejecting ink droplets from the nozzle 159.

[0044] In the carriage 151, the head 155 may be configured to be a single-pass (one-pass) type in which an image is formed by one scan, or may be configured to be a scan (multi-pass) type in which an image is formed by multiple scans. In the case of the single-pass type, the carriage 151 is provided with heads 155 in the number equal to the image formation width in the width direction of the recording medium M (direction perpendicular to the conveying direction T of the recording medium M). In this way, a head module 200 having multiple heads 155 is formed.

[0045] Fig. 3 is a diagram showing a schematic arrangement of the inkjet heads 155 in the head module 200 of the inkjet printer 100 in Fig. 1. As shown in Fig. 3, in the head module 200, the multiple heads 155 are arranged in one or multiple rows with their longitudinal directions aligned with the width direction of the recording medium M, and in each head 155, the multiple nozzles 159 are arranged linearly or in a lattice pattern along the longitudinal direction of the head 155.

[0046] 1 and 2, the reading unit 160 is disposed downstream of the drawing unit 150 in the transport direction T of the recording medium M, and reads an image (e.g., a predetermined pattern image) formed on the recording medium M transported by the transport belt 111. The reading unit 160 outputs the reading result of the predetermined pattern image to the control unit 190. The control unit 190 changes the image formation conditions, such as the image formation position and the drive conditions of the head 55, based on the reading result.

[0047] Although not shown, the inkjet printer 100 also includes a maintenance unit that performs maintenance such as cleaning of the head 155 .

[0048] The operation display unit 170 is, for example, a flat panel display such as a liquid crystal display or an organic EL (Electro Luminescence) display with a touch panel. The operation display unit 170 displays an operation menu for the user, information related to image data, and various states of the inkjet printer 100. The operation display unit 170 also includes a plurality of keys and accepts various input operations from the user.

[0049] The input / output interface 180 mediates the transmission and reception of data between the external device 99 and the control unit 190. The input / output interface 180 is configured, for example, by any one of various serial interfaces, various parallel interfaces, or a combination of these.

[0050] The external device 99 is, for example, a personal computer or a facsimile machine, and supplies print jobs, image data, and the like to the control unit 190 via an input / output interface 180 .

[0051] The control unit 190 is connected to the transport unit 110, supply unit 120, discharge unit 130, ink supply unit 140, drawing unit 150, reading unit 160, operation display unit 170, input / output interface 180, heating unit 195, etc. The control unit 190 controls the overall operation of the inkjet printer 100. The transport unit 110, supply unit 120, discharge unit 130, ink supply unit 140, drawing unit 150, reading unit 160, operation display unit 170, input / output interface 180, heating unit 195, etc. are controlled by the control unit 190 to execute predetermined processes.

[0052] For example, the control unit 190 generates a drive signal for an image to be formed based on image data received from the input / output interface 180, and outputs the drive signal to the head 155. The control unit 190 also has a storage unit (not shown). The storage unit stores a print job input from the external device 99 via the input / output interface 180 and image data related to the print job.

[0053] The inkjet printer 100 having the above configuration supplies the recording medium M from the supply section 120 to the transport section 110 under the control of the control section 190, draws on the recording medium M transported to the transport section 110 using the drawing section 150, and transports the recording medium M with the image formed thereon to the discharge section 130.

[0054] [Configuration of inkjet head 155] Next, the configuration of the head 155 will be described. The configuration described here is the configuration of a single head 155. Note that all heads 155 in the inkjet printer 100 may have the same configuration, or the inkjet printer 100 may include heads 155 with a different configuration from the configuration described below.

[0055] Fig. 4 is a perspective view showing an example of the appearance of the inkjet head 155 in Fig. 1. In the following description, the longitudinal direction of the head 155 is defined as the X-axis direction, the lateral direction of the head 155 is defined as the Y-axis direction, and the height direction of the head 155 is defined as the Z-axis direction.

[0056] 4, head 155 includes housing 101 and exterior member 102 that is fitted to housing 101 on the lower surface side of housing 101. Main components of head 155 are housed inside housing 101 and exterior member 102.

[0057] An inlet 103a and outlets 103b and 103c are arranged on the exterior member 102. The inlet 103a is an ink supply port through which ink is supplied from the outside. The outlets 103b and 103c are ink discharge ports through which ink is discharged to the outside.

[0058] A manifold 156 connected to the inlet 103a is provided inside the exterior member 102. Furthermore, the exterior member 102 is provided with a plurality of mounting holes 104 for mounting the inkjet head 155 to a base plate 200a of the head module 200 (see FIG. 5 for the base plate 200a).

[0059] [Configuration of nozzle position adjustment device 1] Next, the configuration of the nozzle position adjustment device according to the present embodiment 1 will be described. Fig. 5 is a schematic cross-sectional view showing an example of the configuration of the nozzle position adjustment device 1 according to the present embodiment 1. Fig. 6 is a block diagram showing the main parts of a control system of the nozzle position adjustment device 1 of Fig. 5. As shown in Figs. 5 and 6, the nozzle position adjustment device 1 is configured to include an adjustment unit 10, an imaging unit 20, and a control unit 30.

[0060] (Adjustment section 10) In the adjustment unit 10, the head 155 and the base plate 200a of the head module 200 to which the head 155 is attached are arranged, and the adjustment unit 10 adjusts the position of the nozzle 159 provided on the head 155. The adjustment unit 10 has a pedestal 11, a base plate holding unit 12, a head chuck 13, fixing screws 14, a transparent body base 15, and a transparent body 16.

[0061] A base plate 200a of the head module 200 to which the head 155 is attached is placed on the pedestal 11. The base plate holding unit 12 holds the base plate 200a placed on the pedestal 11. Specifically, the base plate holding unit 12 holds the base plate 200a by sandwiching the base plate 200a that is abutted against the pedestal 11 using, for example, a positioning pin (not shown) or the like.

[0062] The head chuck 13 is an adjustment device for adjusting the position of the head 155 arranged on the base plate 200a. The operation of the head chuck 13 is controlled by the control unit 30. By controlling the head chuck 13, the position of the head 155 with respect to the base plate 200a is adjusted. After the position of the head 155 with respect to the base plate 200a is determined, the head 155 is fixed to the base plate 200a with the fixing screws 14 using the driver 19.

[0063] The transparent body base 15 is disposed at a position facing the nozzle surface of the head 155 disposed on the pedestal 11. The transparent body 16 is placed on the transparent body base 15. The transparent body base 15 fixes the placed transparent body 16.

[0064] The transparent body 16 is provided to adjust the position of the head 155. A mark 17 is formed on the transparent body 16, which serves as a reference when adjusting the nozzle 159 of the head 155. The transparent body 16 is accurately positioned in advance using a master head (not shown) that serves as a reference so that the mark 17 is at a predetermined position.

[0065] The mark 17 is formed, for example, at a position corresponding to the endmost nozzle 159 among a plurality of nozzles 159 formed in the head 155. The mark 17 is formed, for example, by depositing a highly reflective metal or the like on the transparent body 16 by sputtering. The mark 17 is formed, for example, in a circular ring shape. Note that the shape of the mark 17 is not limited to this example, and any shape may be used as long as the positional relationship between the mark 17 and the nozzle 159 is clear when aligning the nozzle 159.

[0066] In addition, although details will be described later, in the present embodiment 1, when imaging the nozzle 159 of the head 155, the transparent body 16 needs to have high transparency so that light can be transmitted appropriately. Therefore, it is preferable to use, for example, quartz glass, which has high transparency and a low thermal expansion coefficient, as the transparent body 16.

[0067] Furthermore, it is more preferable that an anti-reflection layer that has been subjected to an anti-reflection treatment to suppress the surface reflection of light is formed on the transparent body 16. This is because the reflection by the transparent body 16 during imaging is reduced, thereby enabling an image with high sharpness to be obtained.

[0068] (Imaging unit 20) The imaging unit 20 individually captures images of the nozzle 159 of the head 155 arranged in the adjustment unit 10 and the mark 17 on the transparent body. The imaging unit 20 has a camera unit 21, an adjustment stage 24, and a vertical movement unit 25.

[0069] The camera unit 21 is an imaging device, and has a lens 22, a coaxial illumination 23a, and a ring illumination 23b. The camera unit 21 captures an image while being focused on the position of the mark 17 of the transparent body 16 or the nozzle 159 of the head 155, and obtains the captured image. The imaging by the camera unit 21 is controlled by the control unit 30.

[0070] Coaxial illumination 23a is an illumination in which a light source is arranged on the optical axis of lens 22 and configured to irradiate light along the optical axis. Coaxial illumination 23a corresponds to the "first illumination" of the present application. Ring illumination 23b is an illumination in which a light source is arranged to surround lens 22 and configured to irradiate light from around the optical axis of lens 22. Ring illumination 23b corresponds to the "second illumination" of the present application.

[0071] The camera unit 21 is placed on the adjustment stage 24. The adjustment stage 24 is provided in order to adjust the position of the camera unit 21 relative to the vertical movement unit 25.

[0072] The vertical moving unit 25 is a moving device on which the camera unit 21 and the adjustment stage 24 are placed, and on which the camera unit 21 can move in a direction perpendicular to the nozzle surface of the head 155 and the transparent body 16. Specifically, the vertical moving unit 25 moves in the up-down direction (Z-axis direction). The operation of the vertical moving unit 25 is controlled by the control unit 30. For example, the vertical moving unit 25 moves the camera unit 21 to the upper end of the vertical moving unit 25 when imaging the nozzle 159 of the head 155 under the control of the control unit 30. Also, the vertical moving unit 25 moves the camera unit 21 to the lower end of the vertical moving unit 25 when imaging the mark 17 of the transparent body 16 under the control of the control unit 30.

[0073] At this time, it is preferable that the vertical moving unit 25 has a high degree of straightness. This is because the higher the accuracy of straightness, the more accurately the vertical moving unit 25 can be moved to a position when it is moved up and down. However, by making the stop positions of the upper and lower ends of the vertical moving unit 25 constant when it is moved, a highly reproducible angle of view can be obtained when the camera unit 21 captures an image at the stop positions. Therefore, as long as the stop position of the vertical moving unit 25 can be set with high accuracy, the accuracy of straightness is not an issue.

[0074] (Control unit 30) The head chuck 13, the camera unit 21, the vertical movement unit 25, etc. are connected to the control unit 30. The control unit 30 comprehensively controls the overall operation of the nozzle position adjustment device 1. The head chuck 13, the camera unit 21, the vertical movement unit 25, etc. are controlled by the control unit 30 to execute predetermined processes.

[0075] The control unit 30 includes a central processing unit (CPU) 31, a random access memory (RAM) 32, a read only memory (ROM) 33, and a storage unit 34.

[0076] The CPU 31 reads out various control programs and setting data stored in the ROM 33, stores them in the RAM 32, and executes the programs to perform various arithmetic processing. The RAM 32 provides a working memory space for the CPU 31 and stores temporary data. The RAM 32 may include a non-volatile memory.

[0077] The ROM 33 stores various control programs and setting data executed by the CPU 31. Note that, instead of the ROM 33, a rewritable non-volatile memory such as an EEPROM (Electrically Erasable Programmable Read Only Memory) or a flash memory may be used.

[0078] The storage unit 34 stores various data and the like used in each part of the nozzle position adjustment device 1. As the storage unit 34, for example, a non-volatile semiconductor memory (so-called flash memory) or an HDD (Hard Disk Drive) is used, and a DRAM (Dynamic Random Access Memory) or the like may also be used in combination.

[0079] Fig. 7 is a functional block diagram showing an example of the configuration of the control unit 30 in Fig. 6. As shown in Fig. 7, the control unit 30 has an image acquisition unit 35, an image generation unit 36, an imaging target identification unit 37, a movement amount calculation unit 38, a movement control unit 39, and a storage unit 34.

[0080] The image acquisition unit 35 acquires a mark image 50 (see FIG. 9) including an image of the mark 17 captured by the camera unit 21, and a nozzle image 60 (see FIG. 12) including an image of the nozzle 159. The image generation unit 36 ​​generates a composite image 70 (see FIG. 14) by combining the mark image 50 and the nozzle image 60 acquired by the image acquisition unit 35.

[0081] The imaging target specifying unit 37 specifies the mark 17 and the nozzle 159, which are the imaging targets, from the composite image 70 generated by the image generating unit 36, based on the feature information previously stored in the storage unit 34. The feature information is information indicating features such as the shape of the mark 17 or the nozzle 159. A specific method for specifying the imaging target will be described later.

[0082] Movement amount calculation unit 38 calculates the amount of movement for matching nozzle 159 with mark 17, based on the amount of deviation of nozzle 159 from mark 17 identified from composite image 70. For example, movement amount calculation unit 38 calculates the amount of movement of nozzle 159, based on position information indicating the positions of identified mark 17 and nozzle 159 within composite image 70.

[0083] The movement control unit 39 controls the vertical movement unit 25 for moving the camera unit 21 when focusing on each of the mark 17 and the nozzle 159. The movement control unit 39 also controls the head chuck 13 for moving the head 155 by the calculated movement amount in order to match the mark 17 and the nozzle 159 included in the composite image 70.

[0084] The storage unit 34 stores various data and the like used in each part of the nozzle position adjustment device 1. For example, the storage unit 34 stores an image captured by the camera unit 21 via the image acquisition unit 35. In addition, for example, the storage unit 34 stores in advance characteristic information for identifying the mark 17 and the nozzle 159 used in the imaging target identification unit 37.

[0085] [Nozzle 159 position adjustment] The adjustment of the position of the nozzle 159 will now be described. Conventionally, the adjustment of the nozzle position has been performed, for example, by aligning the nozzle position with respect to an adjustment mark that is formed in advance on a transparent body that is placed at a precise position. In this case, it is common to simultaneously image the mark and the nozzle, and adjust the nozzle position by moving the head by the amount of deviation of the nozzle from the adjustment mark.

[0086] Here, the alignment of the nozzle is affected by the resolution of the imaging device such as a camera and the magnification of the lens used. For example, in order to perform accurate alignment of the nozzle, a high-resolution imaging device using a high-magnification lens is used. Specifically, for example, when an imaging device with a CMOS size of 4 μm, a pixel count of 5 million pixels, and a lens with a magnification of 8 times are used, the depth of field, which is the focusing range, is about 0.1 mm. This means that in order to simultaneously image the adjustment mark and the nozzle in a focused state, the transparent body on which the adjustment mark is formed and the nozzle need to be positioned within the range of this depth of field (0.1 mm).

[0087] However, if the adjustment mark and the nozzle are arranged so that they are within a depth of field of about 0.1 mm, there is a possibility that the transparent body and the nozzle may come into contact or collide due to variations in product dimensions. From experience, in order to prevent contact or collision between the transparent body and the nozzle, it is necessary to arrange them within a range of about 0.2 mm or more, making the depth of field deeper than in the above example.

[0088] Therefore, the nozzle position adjustment device 1 according to the first embodiment performs a nozzle position adjustment process that can perform accurate alignment while preventing contact or collision between the transparent body 16 and the nozzle 159. In this nozzle position adjustment process, images of the mark 17 and the nozzle 159 formed on the transparent body 16 are individually captured. Then, the nozzle position adjustment device 1 adjusts the position of the nozzle 159 based on a result of combining the individually captured images of the mark 17 and the nozzle 159.

[0089] (Mark 17 image) Fig. 8 is a schematic cross-sectional view showing a state in which the camera unit 21 is focused on the mark 17 in the nozzle position adjustment device 1 of Fig. 5. In the following description, when there is no need to particularly distinguish between the illuminations used, the coaxial illumination 23a and the ring illumination 23b may be simply referred to as "illumination 23".

[0090] When capturing an image of the mark 17 formed on the transparent body 16, first, the vertical movement unit 25 is operated to move the camera unit 21 so that the camera unit 21 focuses on the mark 17. When the illumination 23 is turned on with the camera unit 21 focused on the mark 17, the light from the illumination 23 is reflected by the mark 17 and enters the camera unit 21. As a result, the camera unit 21 obtains a mark image 50 (see FIG. 9) in which the mark 17 is captured.

[0091] Here, when the mark 17 is made of a material with high reflectivity, such as a metal deposited by sputtering, it is preferable to use a coaxial illumination 23a as the illumination 23. This is because the light irradiated to the mark 17 along the optical axis is specularly reflected by the mark 17 and enters the camera unit 21.

[0092] Fig. 10 is a schematic diagram for explaining the irradiation of light by the coaxial lighting 23a when imaging the mark 17. Fig. 10 shows an enlarged view of a part of the adjustment unit 10 (the transparent body 16 and the nozzle 159 of the head 155) and a part of the imaging unit 20 (the camera unit 21) in the nozzle position adjustment device 1. In Fig. 10, the solid arrow indicates the light irradiated from the coaxial lighting 23a, and the dashed arrow indicates the light reflected from the imaging target, etc. The thickness of the arrow also roughly indicates the amount of light.

[0093] 10, when capturing an image of the mark 17, light from the coaxial illumination 23a passes through the lens 22 of the camera unit 21 and is irradiated onto the transparent body 16 and the mark 17 formed on the transparent body 16 along the optical axis of the lens 22. Since the reflectance of the mark 17 is high, most of the light irradiated onto the mark 17 is specularly reflected and enters the camera unit 21.

[0094] Furthermore, the light irradiated to the transparent body 16 is reflected or transmitted depending on the reflectance of the transparent body 16. The light reflected by the transparent body 16 enters the camera unit 21. The light transmitted through the transparent body 16 is reflected by the nozzle 159, and then further transmits through the transparent body 16 to enter the camera unit 21.

[0095] Here, the amount of light reflected from the transparent body 16 is smaller than the amount of light reflected from the mark 17. In addition, the amount of light reflected from the nozzle 159 is also smaller than the amount of light reflected from the mark 17. Therefore, the light reflected from the nozzle 159 and the transparent body 16 can be ignored compared to the light reflected from the mark 17.

[0096] In this way, when the mark 17 is imaged using the coaxial illumination 23a, most of the light irradiated onto the mark 17 is specularly reflected by the mark 17. Therefore, the camera unit 21 can obtain a mark image in which the mark 17 is appropriately imaged.

[0097] In addition, when the mark 17 is formed of a diffusely reflecting material, the light diffusely reflected by the mark 17 enters the camera unit 21. Therefore, the illumination 23 to be used is not limited to the coaxial illumination 23a, and the ring illumination 23b may be used.

[0098] (Image of nozzle 159) Fig. 11 is a schematic cross-sectional view showing a state in which the camera unit 21 is focused on the nozzle 159 in the nozzle position adjustment device 1 of Fig. 5. When capturing an image of the nozzle 159 of the head 155, first, the vertical movement unit 25 is operated to move the camera unit 21 so that the camera unit 21 is focused on the nozzle 159. When the illumination 23 is turned on with the camera unit 21 focused on the nozzle 159, the light from the illumination 23 is reflected by the nozzle 159 and enters the camera unit 21. As a result, the camera unit 21 acquires a nozzle image 60 (see Fig. 12) in which the nozzle 159 is captured.

[0099] Here, the lighting 23 that irradiates the nozzle 159 with light needs to be selected to be optimal depending on the material of the nozzle 159. This is because it may be difficult to properly capture the nozzle image 60 depending on the lighting used.

[0100] For example, if the nozzle 159 is made of a material with low reflectance such as resin, the reflectance of the nozzle 159 is lower than the reflectance of the transparent body 16 disposed closer to the camera unit 21 in the Z-axis direction than the nozzle 159. Therefore, if a coaxial illumination 23a is used as the illumination 23, the amount of light reflected from the transparent body 16 will be greater than the amount of light reflected from the nozzle 159. This makes it difficult for the camera unit 21 to properly capture the nozzle image 60.

[0101] 10, when capturing an image of the nozzle 159, light from the coaxial lighting 23a passes through the lens 22 of the camera unit 21 and is irradiated onto the transparent body 16 along the optical axis of the lens 22. The light irradiated onto the transparent body 16 is reflected or transmitted depending on the reflectance of the transparent body 16. The light reflected by the transparent body 16 enters the camera unit 21.

[0102] Furthermore, the light transmitted through the transparent body 16 is reflected by the nozzle 159, and then transmitted through the transparent body 16 to enter the camera unit 21. At this time, the amount of light reflected from the nozzle 159 is smaller than the amount of light reflected from the transparent body 16 because the reflectance of the nozzle 159 is low. Therefore, it is difficult for the camera unit 21 to obtain a nozzle image that properly captures the nozzle 159.

[0103] On the other hand, when ring illumination 23b is used as illumination 23, the light specularly reflected by transparent body 16 does not enter camera unit 21, and only the light reflected by nozzle 159 enters camera unit 21. Therefore, camera unit 21 can properly capture nozzle image 60.

[0104] Fig. 13 is a schematic diagram for explaining the irradiation of light by the ring illumination 23b when imaging the nozzle 159. As in Fig. 10, Fig. 13 shows an enlarged view of a part of the adjustment unit 10 (the transparent body 16 and the nozzle 159 of the head 155) and a part of the imaging unit 20 (the camera unit 21) in the nozzle position adjustment device 1. In Fig. 13, the solid arrow indicates the light irradiated from the ring illumination 23b, and the dashed arrow indicates the light reflected from the imaging target, etc. The thickness of the arrow also roughly indicates the amount of light.

[0105] 13, when imaging the nozzle 159, the light from the ring illumination 23b is irradiated onto the transparent body 16. The light irradiated onto the transparent body 16 is reflected or transmitted according to the reflectance of the transparent body 16, similar to the example shown in FIG. 10. The light transmitted through the transparent body 16 is irradiated onto the nozzle 159.

[0106] The light irradiated to nozzle 159 is diffusely reflected at nozzle 159. Then, of the diffusely reflected light, the reflected light heading toward camera unit 21 passes through transparent body 16 and enters camera unit 21. On the other hand, the light reflected by transparent body 16 is specularly reflected by transparent body 16, but does not enter camera unit 21 because it enters transparent body 16 at a predetermined angle.

[0107] The amount of light reflected from nozzle 159 is smaller than the amount of light emitted from ring illumination 23b. Therefore, it is preferable that exposure of camera unit 21 be controlled by control unit 30 so as to increase the amount of light captured by camera unit 21.

[0108] In this way, when the nozzle 159 is imaged using the ring illumination 23, the light diffusely reflected by the nozzle 159 enters the camera unit 21, and no other light enters the camera unit 21. Therefore, the camera unit 21 can obtain a nozzle image in which the nozzle 159 is appropriately imaged.

[0109] For these reasons, when the nozzle 159 is made of a material such as resin having a lower reflectance than the transparent body 16, it is preferable to use the ring illumination 23b as the illumination 23.

[0110] Furthermore, when the nozzle 159 is formed of a material with high reflectivity such as metal, the reflectivity of the nozzle 159 is higher than the reflectivity of the transparent body 16. Therefore, the amount of light reflected from the nozzle 159 is greater than the amount of light reflected from the transparent body 16. Therefore, even when the coaxial lighting 23a is used as the lighting 23, a sufficient amount of light can be obtained reflected from the nozzle 159. As a result, when the nozzle 159 is formed of a material with high reflectivity, the camera unit 21 can appropriately capture the nozzle image 60 regardless of which lighting 23 is used.

[0111] In this example, the camera unit 21 of the imaging unit 20 is moved when the camera unit 21 is focused on the mark 17 or the nozzle 159 of the transparent body 16. However, the present invention is not limited to this. For example, the transparent body 16 and the head 155 of the adjustment unit 10 may be moved. In this case, however, it is necessary to move not only the transparent body 16 and the head 155 but also the entire adjustment unit 10 including the driver 19, etc., and a moving device or the like for moving the entire adjustment unit 10 is required. Therefore, in consideration of the increase in size of the entire device and the cost involved in manufacturing the moving device, it is preferable to move the camera unit 21 to focus on the imaging target, as described above.

[0112] (Nozzle 159 Alignment) When the mark image 50 and the nozzle image 60 are captured in this manner, in the nozzle position adjustment process, a composite image 70 is generated by combining the captured mark image 50 and nozzle image 60.

[0113] Fig. 14 is a schematic diagram showing an example of a composite image 70. In Fig. 14, the upper diagram shows the composite image 70 in a state in which the mark image 50 in Fig. 9 and the nozzle image 60 in Fig. 12 are combined. The lower diagram in Fig. 14 shows the composite image 70 in a state in which the head 155 has been moved and the nozzle 159 has been aligned.

[0114] 14, the composite image 70 is obtained by superimposing one of the mark image 50 and the nozzle image 60 on the other image. Therefore, the composite image 70 includes both the mark 17 included in the mark image 50 and the nozzle 159 included in the nozzle image 60.

[0115] As shown in the above diagram, before the nozzle 159 is aligned, the head 155 may not be positioned appropriately, and the position of the nozzle 159 may not match the position of the mark 17. Therefore, in the nozzle position adjustment process according to the first embodiment, the head 155 is moved so that the position of the nozzle 159 matches the position of the mark 17.

[0116] In the nozzle position adjustment process, when moving the head 155, first, the mark 17 and the nozzle 159 are identified from the composite image 70. The mark 17 and the nozzle 159 are identified based on characteristic information previously stored in the storage unit 34. Specifically, for example, when an image having characteristics common to the characteristic information of the mark 17 and the nozzle 159 stored in the storage unit 34 exists in the composite image 70, the mark 17 and the nozzle 159 are identified.

[0117] Here, as described above, the mark 17 on the transparent body 16 is formed at a position corresponding to the endmost nozzle 159 among the multiple nozzles 159 provided in the head 155. Therefore, when identifying the nozzle 159, the endmost nozzle 159 among the multiple nozzles 159 is identified.

[0118] The endmost nozzle 159 is identified, for example, based on features related to the arrangement of the multiple nozzles 159. Specifically, the endmost nozzle 159 is identified using the feature that the multiple nozzles 159 are arranged at equal intervals.

[0119] When a plurality of nozzles 159 in the composite image 70 are identified as described above, it is determined for each nozzle 159 whether or not the nozzle 159 exists at a position spaced apart by a nozzle pitch, which is the interval between adjacent nozzles 159 in the X-axis direction. The nozzle pitch at this time may be stored in advance in the storage unit 34, for example. Then, when it is determined that no nozzle 159 exists at a position spaced apart by the nozzle pitch, the nozzle 159 is determined to be the nozzle 159 at the end.

[0120] Fig. 15 is a schematic diagram for explaining the identification of the endmost nozzle 159. As shown in Fig. 15, the multiple nozzles 159 in the head 155 are arranged in the X-axis direction at a predetermined nozzle pitch, and some of the multiple nozzles 159 are included within the imaging range.

[0121] 15, the image of head 155 including nozzles 159a to 159c is captured, and nozzles 159b and 159c are included within the captured image range. In this case, nozzle 159b included within the captured image range is adjacent to nozzle 159c within the captured image range in the X-axis direction. Note that nozzle 159b is also adjacent to nozzle 159a on the opposite side in the X-axis direction, but the position away from nozzle 159a by the nozzle pitch is outside the captured image range, and therefore the adjacent nozzles 159 are not determined.

[0122] On the other hand, nozzle 159c is adjacent to nozzle 159b in the X-axis direction, but there is no nozzle 159 at a position that is the nozzle pitch away on the opposite side in the X-axis direction. Therefore, in this example, nozzle 159c is determined to be the nozzle 159 at the end.

[0123] Next, when the mark 17 and the nozzle 159 at the extreme end are identified, the positions of the identified mark 17 and nozzle 159 are identified. The positions of the mark 17 and the nozzle 159 are identified based on position information, which is information relating to their respective positions within the composite image 70.

[0124] The position information may be, for example, coordinates in the X-axis direction and the Y-axis direction in the composite image 70. That is, the positions of the mark 17 and the nozzle 159 in this case are specified by the coordinates in the X-axis direction and the Y-axis direction in the composite image 70.

[0125] Once the positions of the mark 17 and the nozzle 159 have been specified, the amount of movement of the head 155 is then calculated based on the coordinates of the specified mark 17 and nozzle 159 in the composite image 70. Specifically, the difference values ​​between the coordinates of the mark 17 and the nozzle 159 in the X-axis direction and the Y-axis direction are calculated based on the coordinates of the mark 17. These difference values ​​become the amount of movement of the head 155 in each of the X-axis direction and the Y-axis direction.

[0126] Finally, the head chuck 13 is operated to move the head 155 by the calculated movement amount, so that the position of the nozzle 159 coincides with the position of the mark 17, as shown in the lower diagram of Fig. 14. This allows the head 155 to be positioned in an appropriate position.

[0127] [Nozzle position adjustment process] FIG. 16 is a flowchart showing an example of the flow of the nozzle position adjustment process performed by the nozzle position adjustment device 1 according to the first embodiment.

[0128] In step S1, the movement control unit 39 of the control unit 30 controls the vertical movement unit 25 to move the camera unit 21 so as to focus on the mark 17 formed on the transparent body 16. As a result, the camera unit 21 captures an image of the transparent body 16 in a state focused on the mark 17, and obtains the mark image 50.

[0129] In step S2, the image acquisition unit 35 acquires the mark image 50 captured by the camera unit 21. The image acquisition unit 35 supplies the acquired mark image 50 to the image generation unit 36, and also causes the storage unit 34 to store the mark image 50.

[0130] In step S3, movement control unit 39 controls vertical movement unit 25 to move camera unit 21 so as to focus on nozzles 159 of head 155. As a result, camera unit 21 captures an image of the nozzle surface of head 155 while focused on nozzles 159, and acquires nozzle image 60.

[0131] In step S4, the image acquisition unit 35 acquires the nozzle image 60 captured by the camera unit 21. The image acquisition unit 35 supplies the acquired nozzle image 60 to the image generation unit 36, and also causes the storage unit 34 to store it.

[0132] The order of the processes in steps S1 and S2 and the processes in steps S3 and S4 may be interchanged.

[0133] In step S5, the image generating unit 36 ​​superimposes one of the received mark image 50 and nozzle image 60 on the other image to generate a composite image 70.

[0134] In step S6, the imaging target specifying section 37 specifies the mark 17 and the nozzle 159 at the end from the composite image 70 generated by the image generating section 36. In this case, the imaging target specifying section 37 reads out the characteristic information from the storage section 34, and judges whether or not an image having a characteristic common to the read characteristic information is present in the composite image 70. Then, the imaging target specifying section 37 specifies the mark 17 and the nozzle 159 when an image having a characteristic common to the characteristic information is present in the composite image 70.

[0135] In step S7, the movement amount calculation unit 38 specifies the positions of the specified mark 17 and nozzle 159 in the composite image 70. Then, the movement amount calculation unit 38 calculates the movement amount of the head 155 based on the position information of the mark 17 and the nozzle 159.

[0136] In step S8, the movement control unit 39 controls the head chuck 13 so as to move the head 155 by the movement amount calculated by the movement amount calculation unit 38. This causes the head 155 to move, and the nozzle 159 is placed at an appropriate position.

[0137] As described above, the nozzle position adjustment device 1 according to the first embodiment generates a composite image 70 by combining a mark image 50 obtained by focusing on the mark 17 on the transparent body 16 and capturing an image of the mark, and a nozzle image 60 obtained by focusing on the nozzle 159 and capturing an image of the nozzle 159. Then, based on the generated composite image 70, the nozzle position adjustment device 1 moves the head 155 so that the mark 17 and the nozzle 159 coincide with each other.

[0138] As a result, a composite image 70 indicating the positional relationship between the mark 17 and the nozzle 159 is generated without bringing the transparent body 16 close to the nozzle 159. In addition, the amount of movement of the head 155 is derived from the positional relationship between the mark 17 and the nozzle 159. Therefore, the position of the nozzle 159 can be adjusted with high precision while the inkjet head 155 can be manufactured stably and efficiently.

[0139] In this example, it has been described that the amount of movement of the head 155 is calculated based on the position information of the mark 17 and the nozzle 159 contained in the composite image obtained by combining the mark image and the nozzle image, but it is not necessary to generate a composite image. For example, the position of the mark 17 may be specified from the mark image, and the position of the nozzle 159 may be specified from the nozzle image, and the amount of movement of the head 155 may be calculated based on the respective specified position information.

[0140] <Embodiment 2> Next, a description will be given of the present embodiment 2. In the present embodiment 2, the same reference numerals are given to the parts common to the embodiment 1, and detailed description will be omitted.

[0141] Generally, the heads 155 are arranged in a line or a grid in the head module 200. The heads 155 are arranged in this manner mainly to increase the printing width of the head module 200 and improve the resolution.

[0142] Here, in order to improve the resolution, it is necessary to line up the multiple heads 155 with the nozzle positions shifted by a specified dimension. In this case, it is not enough to simply shift the multiple heads 155 by a specified dimension, but it is necessary to take into consideration the actual printing length of the heads 155. This is because if there is a large difference in the printing length of each of the multiple heads 155, the dimensions at the ends will not match, resulting in printing defects.

[0143] Therefore, in the second embodiment, a plurality of heads 155 are arranged in consideration of the difference in the printing length.

[0144] Fig. 17 is a schematic diagram showing an example of the arrangement of a plurality of heads 155 in a head module 200 according to the second embodiment. Fig. 17 shows a state in which a first inkjet head (hereinafter referred to as "first head") 155a and a second inkjet head (hereinafter referred to as "second head") 155b are arranged with a predetermined distance between them. In this example, the printing length L1 of the first head 155a and the printing length L2 of the second head 155b are different dimensions.

[0145] 17, the first head 155a has a plurality of nozzles 159 including nozzles 159A1 and 159A2 on both ends. The second head 155b has a plurality of nozzles 159 including nozzles 159B1 and 159B2 on both ends.

[0146] In such a head module 200, in order to arrange the first head 155a and the second head 155b taking into consideration the difference in printing length, it is desirable to equalize the amount of misalignment of the nozzles 159 at both ends of each head 155. Specifically, the first head 155a and the second head 155b are arranged so that the amount of misalignment La between nozzle 159A1 and nozzle 159B1 and the amount of misalignment Lb between nozzle 159A2 and nozzle 159B2 are equal.

[0147] In this case, the amount of misalignment Lc of the second head 155b relative to the first head 155a is calculated based on formula (1). In formula (1), "L" represents the desired amount of head misalignment of the second head 155b relative to the first head 155a. Lc = L - ((L2 - L1) / 2) (1)

[0148] In this manner, the printing length L1 of the first head 155a and the printing length L2 of the second head 155b are measured, and the desired head misalignment amount L is set, whereby the misalignment amount Lc of the second head 155b relative to the first head 155a is calculated. The misalignment amount Lc at this time takes into consideration the difference in printing length among the multiple heads 155. Then, the coordinates indicating the position of the second head 155b are determined based on the calculated misalignment amount Lc. As a result, the coordinates of the nozzles 155 of the second head 155b are determined.

[0149] As described above, in the second embodiment, the multiple heads 155 are arranged in the head module 200 taking into consideration the difference in printing length between them. Therefore, printing misalignment due to the difference in printing length between the multiple heads 155 can be suppressed. [Explanation of symbols]

[0150] 1 Nozzle position adjustment device 10 Adjustment part 11 Pedestal 12 Base plate holder 13 Head chuck 14 Fixing screw 15 Transparent base 16 Transparent body 17 Marks 19 Driver 20 Imaging unit 21 Camera Division 22 Lens 23a coaxial lighting 23b Ring lighting 24 Adjustment stage 25 Vertical moving part 30 Control section 31 CPU 32 RAM 33 ROM 34 Storage section 35 Image acquisition unit 36 Image Generation Unit 37 Imaging target identification unit 38 Travel amount calculation section 39 Movement control section 50 Mark Images 60 Nozzle Images 70 Composite Images 100 Inkjet Printer 101 Case 102 Exterior materials 103a Inlet 103b, 103c Outlet 104 Mounting hole 155 Inkjet head 155a First inkjet head 155b Second inkjet head 159, 159a, 159b, 159c nozzles 200 Head Module 200a Base plate

Claims

1. a transparent body disposed opposite a nozzle surface of an inkjet head having a plurality of nozzles and having marks formed at predetermined positions; an imaging device that captures a mark image including the mark in a state focused on the mark, and a nozzle image including the nozzle in a state focused on the nozzle; a control unit that moves the inkjet head based on the mark image and the nozzle image so that the mark and the nozzle are aligned; Equipped Nozzle position adjustment device.

2. The control unit is generating a composite image by combining the mark image and the nozzle image; Based on the generated composite image, the inkjet head is moved so that the mark and the nozzle are aligned. The nozzle position adjustment device according to claim 1 .

3. The imaging device includes: The mark image is captured using a first illumination that irradiates light along an optical axis of a lens. The nozzle position adjustment device according to claim 1 .

4. The imaging device includes: A light source is disposed so as to surround the optical axis of the lens, and the nozzle image is captured using a second illumination that irradiates light from the periphery of the optical axis. The nozzle position adjustment device according to claim 1 .

5. The imaging device further includes a moving unit that moves the imaging device in a direction perpendicular to the nozzle surface and the transparent body so as to focus on the mark and the nozzle separately. The nozzle position adjustment device according to claim 1 .

6. The control unit is Identifying a position of the mark included in the mark image and a position of the nozzle included in the nozzle image; A movement amount of the inkjet head is calculated based on the identified positions of the mark and the nozzle. The nozzle position adjustment device according to claim 1 .

7. The inkjet head further includes an adjustment device for adjusting a position of the inkjet head. The control unit is The adjustment device is controlled so as to move the inkjet head by the calculated movement amount. The nozzle position adjustment device according to claim 6.

8. The mark is The nozzles are formed at positions corresponding to the outermost nozzles of the plurality of nozzles, The control unit is The inkjet head is moved so that the endmost nozzle and the mark are aligned. The nozzle position adjustment device according to claim 1 .

9. The control unit is The outermost nozzle is identified based on an interval between adjacent nozzles among the plurality of nozzles. The nozzle position adjustment device according to claim 8.

10. The transparent body is The nozzle surface is located at a distance of 0.2 mm or more. The nozzle position adjustment device according to claim 1 .

11. The transparent body is An anti-reflection layer is formed to suppress surface reflection of light The nozzle position adjustment device according to claim 1 .

12. The transparent body is Made of quartz glass The nozzle position adjustment device according to claim 1 .

13. capturing a mark image including a mark formed at a predetermined position on a transparent body arranged opposite a nozzle surface of an inkjet head having a plurality of nozzles, while focusing on the mark; capturing a nozzle image including the nozzle while focusing on the nozzle; The inkjet head is moved based on the mark image and the nozzle image so that the mark and the nozzle are aligned. How to adjust the nozzle position.

14. A program for causing a computer to execute the nozzle position adjustment method according to claim 13.

Images