Print method, print head unit, and robot system

Abstract

To provide a print method which can modify a print result by a curable ink even if the print result is defective, and to provide a print head unit and a robot system.SOLUTION: In a print method, an ink discharge head and a robot including a robot arm configured to support and move the ink discharge head are used and the ink discharge head discharges a curable ink with the robot causing the ink discharge head to scan to make prints on an object. The print method includes: a step in which the ink discharge head discharges the curable ink toward the object; a step in which the curable ink discharged to the object is inspected and an inspection result is output; a step in which whether or not the inspection result meets the inspection standards is determined; and a step in which the curable ink discharged to the object is cured when the inspection result meets the standards.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a printing method, a print head unit and a robot system. [Background technology]

[0002] 2. Description of the Related Art Three-dimensional object printing devices are known that perform printing on the surface of a three-dimensional object by moving an inkjet print head using a combination of movements of a plurality of movable parts.

[0003] For example, Patent Document 1 discloses a system for inkjet printing on a three-dimensional object, the system comprising a joint-arm robot, a print head, and a piezoelectric actuator disposed between them. The robot is configured to move the print head along the surface of the object, thereby enabling inkjet printing on non-flat areas. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2013-202781 A Summary of the Invention [Problem to be solved by the invention]

[0005] Inkjet printing can also use curable ink. After being ejected onto an object, the curable ink is cured, for example, by being irradiated with ultraviolet light or by being heated. For this reason, it is difficult to remove ink that has completed curing, and there is a problem that even if the print result is defective, it cannot be corrected. Therefore, there is a demand for a printing method that can correct a defective print result in printing performed by a robot ejecting curable ink. [Means for solving the problem]

[0006] A printing method according to an application example of the present invention includes: A printing method using an ink ejection head and a robot having a robot arm that supports and moves the ink ejection head, the method comprising the steps of: scanning the ink ejection head with the ink ejection head ejecting a curable ink to print on an object, the method comprising the steps of: A step of ejecting the curable ink from the ink ejection head toward the target; inspecting the curable ink ejected onto the object and outputting an inspection result; determining whether the inspection result is pass or not; If the test result is a pass, curing the curable ink ejected onto the object; Includes.

[0007] The print head unit according to the application example of the present invention includes: A print head unit that is supported by a robot arm and scans an object to print, A mounting portion that is attached to the robot arm; an ink ejection head that ejects curable ink; an inspection device that inspects the ejected curable ink; a curing device that cures the discharged curable ink; Equipped with.

[0008] A robot system according to an application example of the present invention includes: A robot system that prints on an object, an ink ejection head that ejects curable ink; a robot having a robot arm that supports and moves the ink ejection head; an inspection device that inspects the ejected curable ink; a curing device that cures the discharged curable ink; a control device that controls the operations of the ink ejection head, the robot, the inspection device, and the curing device to perform the printing; Equipped with The control device includes: an inspection result acquisition unit that acquires inspection results output from the inspection device; A determination unit that determines whether the inspection result is pass or not; a curing processing unit that causes the curing device to cure the curable ink when the test result is a pass; has. [Brief description of the drawings]

[0009] [Figure 1] 1 is a perspective view showing an overall configuration of a robot system according to a first embodiment. [Diagram 2] FIG. 2 is a functional block diagram of the robot system shown in FIG. [Diagram 3] FIG. 2 is a plan view showing the print head unit shown in FIG. [Figure 4] 4 is a flowchart illustrating a printing method according to the first embodiment. [Diagram 5] 5 is a diagram for explaining the printing method shown in FIG. 4, and is a diagram for explaining the operation of the robot system in each step shown in FIG. [Figure 6] 5 is a diagram for explaining the printing method shown in FIG. 4, and is a diagram for explaining the operation of the robot system in each step shown in FIG. [Figure 7] 5 is a diagram for explaining the printing method shown in FIG. 4, and is a diagram for explaining the operation of the robot system in each step shown in FIG. [Figure 8] 5 is a diagram for explaining the printing method shown in FIG. 4, and is a diagram for explaining the operation of the robot system in each step shown in FIG. [Figure 9] 5 is a diagram for explaining the printing method shown in FIG. 4, and is a diagram for explaining the operation of the robot system in each step shown in FIG. [Figure 10] FIG. 11 is a side view showing a partial configuration of a robot system according to a second embodiment. [Figure 11]FIG. 11 is a side view showing a partial configuration of a robot system according to a second embodiment. [Figure 12] FIG. 11 is a side view showing a partial configuration of a robot system according to a second embodiment. [Figure 13] 13 is a flowchart illustrating a printing method according to a third embodiment. [Figure 14] 14 is a side view showing a partial configuration of a print head unit and a robot system used in the printing method shown in FIG. 13. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of a printing method, a print head unit, and a robot system according to the present invention will be described in detail with reference to the accompanying drawings.

[0011] 1. First embodiment First, a printing method, a print head unit, and a robot system according to a first embodiment will be described.

[0012] 1.1.Robot System Fig. 1 is a perspective view showing the overall configuration of a robot system 100 according to the first embodiment. Fig. 2 is a functional block diagram of the robot system 100 shown in Fig. 1. Fig. 3 is a plan view showing the print head unit 10 shown in Fig. 1.

[0013] The robot system 100 shown in FIG. 1 comprises a robot 200, a print head unit 10 (the print head unit according to the first embodiment), a fixing member 700 that supports and fixes an object Q, and a control device 900.

[0014] The robot 200 is a six-axis vertical articulated robot having six drive axes. The robot 200 has a base 210 fixed to the floor, a robot arm 220 connected to the base 210, and a moving stage 300 attached to the robot arm 220. The moving stage 300 may be provided as necessary and may be omitted. In that case, the print head unit 10 may be directly attached to the robot arm 220. The robot 200 may have more or fewer drive axes than six. The robot 200 may be a horizontal articulated robot, or a multi-arm robot having multiple robot arms.

[0015] The robot arm 220 is a robotic arm in which a plurality of arms 221, 222, 223, 224, 225, and 226 are rotatably connected, and includes six joints J1 to J6. Among these, the joints J2, J3, and J5 are bending joints, and the joints J1, J4, and J6 are torsion joints. The robot arm 220 is also provided with an arm drive mechanism 230 shown in FIG. 2. The arm drive mechanism 230 is composed of a motor M and an encoder E provided at each of the joints J1, J2, J3, J4, J5, and J6 shown in FIG. 1. The motor M is a drive source that drives each of the joints J1, J2, J3, J4, J5, and J6. The encoder E detects the amount of rotation of the motor M (the rotation angle of the arm).

[0016] 1, the print head unit 10 is attached to the tip of the arm 226 via a moving stage 300. The print head unit 10 shown in FIG. 1 comprises an attachment portion 11, an ink ejection head 400, an inspection device 500, and a curing device 800.

[0017] The mounting unit 11 is connected to the tip of the arm 226 via a moving stage 300. The mounting unit 11 also supports the ink ejection head 400, the inspection device 500, and the curing device 800. Such a mounting unit 11 is configured, for example, by a plate having sufficient rigidity. This allows the ink ejection head 400, the inspection device 500, and the curing device 800 to be connected to the robot arm 220 while maintaining their relative positions. The configuration of the mounting unit 11 is not limited to this.

[0018] 3, the ink ejection head 400 has an ink chamber (not shown), a vibration plate arranged on the wall of the ink chamber, and ink ejection holes 411 connected to the ink chamber, and is configured such that ink in the ink chamber is ejected from the ink ejection holes 411 by vibration of the vibration plate. However, the configuration of the ink ejection head 400 is not particularly limited.

[0019] The ink ejected from the ink ejection head 400 is a curable ink. The curable ink is ink that has the property of undergoing a curing reaction and curing after being ejected in an uncured state. Since the timing of the curing reaction can be selected, the ink can be appropriately fixed on the object Q made of various materials. Examples of the curable ink include ultraviolet curable ink (UV ink) and heat curable ink (resin ink). Of these, the ultraviolet curable ink is an ink that is cured in a short time by irradiating ultraviolet rays, and therefore the range of wetting and spreading is particularly easy to control, making it useful as ink to be ejected from the ink ejection head 400. On the other hand, there are also water-based inks as heat-curable inks. Water-based inks are useful as inks that produce little odor and are easy to handle.

[0020] The robot system 100 also includes a print controller 420. The ink ejection head 400 is connected to the print controller 420 as shown in Fig. 2. In the example of Fig. 1, the print controller 420 is attached to the tip of the arm 226 via the moving stage 300, similar to the ink ejection head 400. The print controller 420 controls the operation of the ink ejection head 400 based on a control signal output from the control device 900.

[0021] The print controller 420 includes, for example, a processor such as one or more CPUs (Central Processing Units), a memory, an external interface, etc. The print controller 420 may include a programmable logic device such as an FPGA (Field Programmable Gate Array) instead of or in addition to a CPU. The print controller 420 may be incorporated in the control device 900.

[0022] 3, the inspection device 500 has an imaging unit 510. The imaging unit 510 captures an image of the ink ejected onto the object Q. The ejected ink can be inspected based on the image captured by the imaging unit 510. In this specification, "inspection" refers to capturing an image of a coating film formed by the ejected ink.

[0023] In this embodiment, the inspection device 500 is included in the print head unit 10, but this is not necessarily required. In that case, the inspection device 500 may be provided, for example, at any position on the robot arm 220, or at a position different from the robot arm 220. Examples of positions different from the robot arm 220 include the ceiling, walls, and supports erected on the floor of the space in which the robot 200 is placed.

[0024] The imaging unit 510 is, for example, a camera. Examples of the camera include a monochrome camera, a color camera, and a spectroscopic camera.

[0025] Among these, monochrome cameras and color cameras can capture images that contain at least two-dimensionally distributed brightness information. Brightness information is the brightness value of two-dimensional pixels. By using such images, the position and shape of the ink ejected on the target Q can be inspected.

[0026] In addition, the spectroscopic camera can obtain images that include at least two-dimensional luminance information and color information. Color information is the chromaticity and brightness of a pixel. By using images with such color information, it is possible to inspect not only the position and shape of the ink ejected onto the object Q, but also the color of the ink, i.e., the type of ink.

[0027] 3, the curing device 800 has an ultraviolet ray irradiation unit 810. The ultraviolet ray irradiation unit 810 irradiates ultraviolet rays toward the ink ejected onto the target Q. This allows the ultraviolet ray curable ink to be cured and fixed.

[0028] The curing device 800 may have devices other than the ultraviolet irradiating unit 810. Examples of such devices include a resistance heater and an infrared heater. When using such devices, the ink may be a thermosetting ink.

[0029] In this embodiment, the curing device 800 is included in the print head unit 10, but this is not necessarily required. In that case, the curing device 800 may be provided, for example, at any position on the robot arm 220, or at a position different from the robot arm 220. Examples of positions different from the robot arm 220 include a ceiling, a wall, or a support erected on the floor of the space in which the robot 200 is placed.

[0030] As shown in FIG. 3, the moving stage 300 has a base 310 connected to the arm 226, a stage 320 that moves relative to the base 310, and a moving mechanism 330 that moves the stage 320 relative to the base 310. As shown in FIG. 3, when the three mutually orthogonal axes are the X-axis, the Y-axis, and the Z-axis, the stage 320 has a Y-stage 320Y that can move in the direction along the Y-axis relative to the base 310, and an X-stage 320X that can move in the direction along the X-axis relative to the Y-stage 320Y. The X-stage 320X and the Y-stage 320Y are linearly guided in the X-axis and Y-axis directions by linear guides (not shown), and can move smoothly. The print head unit 10 is attached to the X-stage 320X. The stage 320 may have a rotating stage that can rotate around the Z-axis relative to the base 310.

[0031] The movement mechanism 330 has a Y movement mechanism 330Y that moves the Y stage 320Y in a direction along the Y axis relative to the base 310, and an X movement mechanism 330X that moves the X stage 320X in a direction along the X axis relative to the Y stage 320Y.

[0032] The Y-moving mechanism 330Y and the X-moving mechanism 330X each have a piezoelectric actuator 340 as a driving source. The piezoelectric actuator 340 vibrates by utilizing the expansion and contraction of a piezoelectric element, and the vibration is transmitted to the X-stage 320X and the Y-stage 320Y to move them. In other words, the moving stage 300 is configured to move the print head unit 10 relative to the robot arm 220 by piezoelectric drive. This allows the moving stage 300 to be made smaller and lighter. In addition, the driving accuracy of the moving stage 300 is improved. Furthermore, the piezoelectric actuator 340 is useful in that it does not require an additional brake because of its large holding torque when stopped, and in that the positional stability of the stage 320 when stopped is high. The driving source may be an actuator other than the piezoelectric actuator 340.

[0033] 1 and 2, the robot system 100 also includes a robot controller 600. The motor M and the encoder E are connected to the robot controller 600. The robot controller 600 controls the operation of the robot 200 based on a control signal output from the control device 900.

[0034] The robot controller 600 has, as functional units, an arm control unit 610, a moving stage controller 620, and a memory unit 630.

[0035] The arm control unit 610 outputs a control signal that controls the operation of the arm drive mechanism 230, thereby controlling the robot arm 220 to a desired posture.

[0036] The moving stage controller 620 outputs a control signal that controls the operation of the moving stage 300, thereby moving the print head unit 10 to a target position relative to the robot arm 220. Note that the moving stage controller 620 may be independent from the robot controller 600.

[0037] The memory unit 630 stores programs necessary for processing by the robot controller 600, data necessary for executing the programs, and the like.

[0038] The robot controller 600 includes, for example, one or more processors such as CPUs, a memory, an external interface, etc. Note that the robot controller 600 may include a programmable logic device such as an FPGA instead of or in addition to a CPU.

[0039] The control device 900 controls the operations of the robot controller 600, the print controller 420, the inspection device 500, and the curing device 800 to execute printing on the target object Q. As shown in Fig. 2, the control device 900 has, as functional units, a print control unit 910 and a storage unit 930. The print control unit 910 includes a print data generation unit 912, an inspection result acquisition unit 914, a determination unit 916, and a curing processing unit 918.

[0040] The print data generation unit 912 generates print data and outputs it to the robot controller 600 and the print controller 420. The print data is data constituting characters, images, etc. to be printed on the target Q.

[0041] The inspection result acquisition unit 914 controls the operation of the inspection device 500, and causes the inspection device 500 to capture an image of the ink immediately after it has been ejected onto the printing surface Q1 of the object Q. Then, the obtained image is output and acquired as the inspection result.

[0042] The determination unit 916 determines whether the test result acquired by the test result acquisition unit 914 passes or fails. For example, when the test result is an image including two-dimensional luminance information, the method of determining whether the test result passes or fails is to determine whether a pattern formed by the position and shape of the ejected ink matches a pattern included in a preregistered template image, that is, a pass criterion. In this determination, the pass or fail is determined based on a known template matching technique.

[0043] Also, in the case where the inspection result is an image including color information, a method of judging whether or not the chromaticity and brightness consisting of the hue and saturation of the ejected ink meets a preregistered pass standard can be used. Specifically, for example, a method of judging whether or not the difference (color difference ΔE) between the color information included in the inspection result and the reference color is within a predetermined range in the L*a*b* color system can be used. Then, when the color difference ΔE is within the predetermined range, the judging unit 916 judges that the pass standard is met and that the result is pass, and when it is not within the predetermined range, it judges that the pass standard is not met and that the result is fail (fail). By using the color information in this way, it is possible to perform a pass / fail judgment based on not only the position and shape of the ejected ink but also the color of the ink. As a result, it is possible to suppress the occurrence of color defects in the print result.

[0044] The curing processing unit 918 controls the curing of the coating film by the curing device 800. If the judgment by the judgment unit 916 is a pass, the curing device 800 irradiates ultraviolet light to cure the ink being inspected. On the other hand, if the judgment by the judgment unit 916 is a fail, the curing device 800 does not irradiate ultraviolet light.

[0045] The storage unit 930 stores programs necessary for the operation of the control device 900, data necessary for executing the programs, and the like.

[0046] The control device 900 is, for example, configured as a computer, and includes a processor (CPU) for processing information, a memory communicatively connected to the processor, and an external interface. In addition, various programs executable by the processor are stored in the memory, and the processor realizes the above-mentioned functions by reading and executing the various programs stored in the memory. Note that the control device 900 may include a programmable logic device such as an FPGA instead of or in addition to the CPU.

[0047] The configuration of the robot system 100 according to the first embodiment has been described above, but the moving stage 300 may be attached to a position away from the robot arm 220, for example to a fixed member 700, and support the target object Q. In this case, the moving stage 300 may be configured to finely adjust the position of the target object Q in synchronization with the operation of the robot arm 220. The moving stage 300 may also have a function of moving the print head unit 10 so as to cancel out wobble of the robot arm 220 in, for example, an orthogonal direction D2 orthogonal to a printing direction D1, which will be described later.

[0048] 1.2.Printing method Next, a description will be given of a printing method according to the first embodiment. In the following description, a method using the above-described robot system 100 will be described as an example.

[0049] Fig. 4 is a flowchart for explaining the printing method according to the first embodiment. Fig. 5 to Fig. 9 are diagrams for explaining the printing method shown in Fig. 4, and are diagrams for explaining the operation of the robot system 100 in each step shown in Fig. 4.

[0050] In the printing method according to the first embodiment, the robot 200 scans the print head unit 10 in a printing direction D1 relative to the object Q while the ink ejection head 400 ejects ink 40 to print on the object Q.

[0051] 4 includes an ink ejection step S102, an inspection step S104, a determination step S106, an ink removal step S108, and a curing step S 110. Each step will be described below in order.

[0052] 1.2.1. Ink ejection step In the ink ejection step S102, the print data generation unit 912 of the print control unit 910 acquires the shape, size, etc. of the printing surface Q1 of the target object Q. Then, the operating conditions of the robot 200 on the printing surface Q1 are determined. The operating conditions are not particularly limited, but may include, for example, the attitude, movement path, acceleration, deceleration, and maximum speed of the robot arm 220 on the printing surface Q1, as well as the movement amount and movement speed of the moving stage 300. These operating conditions are set by the print data generation unit 912 based on information previously input to the print control unit 910 and image data input as appropriate.

[0053] Next, in the ink ejection step S102, the print data generated by the print data generation unit 912 is output to the robot controller 600 and the print controller 420. The robot controller 600 controls the operation of the robot 200 based on the print data. The print controller 420 controls the operation of the ink ejection head 400 based on the print data. Then, while the robot 200 scans the print head unit 10 in the print direction D1, the ink ejection head 400 ejects the ink 40 toward the print surface Q1, as shown in FIG. 5. The ejected ink 40 lands in a range (predetermined range) set in the print data, forming a coating film 42. The "predetermined range" here refers to a minimum unit area in which the coating film 42 is formed and then inspected and cured in a step described later. The formation of the coating film 42 and the inspection and curing in a step described later are repeated for each predetermined range, thereby finally obtaining the desired print result.

[0054] 1.2.2. Inspection steps In the inspection step S104, the ink 40 discharged onto the printing surface Q1, that is, the coating film 42 formed on the printing surface Q1, is inspected. Specifically, as shown in FIG. 6, the inspection device 500 captures an image of the coating film 42. The inspection result acquisition unit 914 of the control device 900 acquires the obtained image as the inspection result. Since the inspection device 500 is incorporated in the print head unit 10, the coating film 42 can be inspected for each predetermined range. This allows the size of the image for inspection to be small, and the inspection device 500 can be simplified. This allows the inspection step S104 and the judgment step S106 to be performed at high speed. In addition, since the waiting time for the inspection can be prevented from becoming long, it is possible to prevent the coating film 42 from undergoing unintended changes such as spreading.

[0055] Note that instead of performing the inspection immediately after forming the coating film 42 in a predetermined range, the coating film 42 may be formed in a predetermined range over multiple units, and then the multiple units of the coating film 42 may be inspected together. The predetermined range of the coating film 42 is not particularly limited, and is set in consideration of, for example, the inspection range of the inspection device 500, the drying time of the ink 40, etc.

[0056] 1.2.3. Judgment step In the determination step S106, the determination unit 916 of the control device 900 determines whether or not the inspection result is pass based on the pass criterion.

[0057] If the inspection result is pass, the process proceeds to the curing step S110. On the other hand, if the inspection result is no, that is, not pass, the process proceeds to the ink removal step S108. This makes it possible to prevent the coating film 42 that has failed the inspection (the coating film 42 with printing defects) from proceeding directly to the curing step S110 described below. As a result, it is possible to reduce the man-hours and costs required for preparing a new target object Q, while ultimately obtaining a print result with fewer defects.

[0058] 1.2.4. Ink removal step In the ink removal step S108, the ink 40 discharged onto the printing surface Q1, i.e., the coating film 42, is removed. This makes it possible to regenerate the object Q and prevent the object Q from being wasted. Since the coating film 42 is made of uncured ink 40, it can be removed by various removal methods. Examples of methods for removing the coating film 42 include wiping, blotting, washing, etc.

[0059] After removing the coating film 42, the process returns to the ink ejection step S102 and printing is resumed. In this case, in the ink ejection step S102 after printing is resumed, the print data is set so that printing is resumed from the portion removed in the ink removal step S108.

[0060] 1.2.5. Curing step In the curing step S110, if the inspection result is a pass, a curing process is performed on the coating film 42 that was the subject of the inspection by irradiating it with ultraviolet rays UV, as shown in FIG. 7. This causes the coating film 42 to cure, and a cured film 44 shown in FIG. 8 is obtained. In this manner, a cured film 44 that faithfully reflects the printing data is obtained. According to the printing method as described above, it is possible to prevent the occurrence of a cured film 44 with printing defects. As a result, it is possible to obtain a print result with the desired shape.

[0061] The coating film 42 is cured for each predetermined area. This reduces the irradiation area of ​​the ultraviolet ray UV, which allows the curing device 800 to be made smaller. In addition, the waiting time for curing can be prevented from becoming long, which can prevent the coating film 42 from changing in an unintended manner, such as spreading out.

[0062] It should be noted that rather than inspecting a predetermined area of ​​the coating film 42 and then curing it immediately after, it is also possible to inspect multiple units of the coating film 42 in a predetermined area and then cure the multiple units of the coating film 42 together.

[0063] By repeating the formation of the cured film 44 by the printing method as described above, the cured film 44 can be made continuous, as shown in Fig. 9. This makes it possible to obtain a cured film 46 that reflects the printing data.

[0064] 3, the ink ejection head 400, the inspection device 500, and the curing device 800 are arranged in this order, and are scanned as a unit by the robot 200. Therefore, when the print head unit 10 is scanned in the printing direction D1 immediately after the coating film 42 is formed by the ink ejection head 400, the inspection device 500 and the curing device 800 move sequentially over the coating film 42. This allows the ejection of the ink 40, the inspection of the coating film 42, and the curing of the coating film 42 to be performed continuously. As a result, the continuous occurrence of printing defects is suppressed, and highly accurate printing results can be obtained efficiently.

[0065] 2. Second embodiment Next, a print head unit and a robot system according to a second embodiment will be described.

[0066] 10 to 12 are side views showing a partial configuration of a robot system 100 according to the second embodiment.

[0067] The second embodiment will be described below, focusing on the differences from the first embodiment and omitting the description of the similarities. Note that in Figures 10 to 12, the same reference numerals are used for the same configurations as the first embodiment.

[0068] The robot system 100 according to the second embodiment is similar to the robot system 100 according to the first embodiment, except that the ink ejection head 400, the inspection device 500, and the curing device 800 are attached to different robots 200A, 200B, and 200C.

[0069] In the second embodiment, first, as shown in Fig. 10, ink 40 is discharged from an ink discharge head 400 attached to a robot 200A. Then, a coating film 42 is formed on a printing surface Q1.

[0070] Next, the inspection device 500 attached to the robot 200B is moved onto the coating film 42. Then, as shown in FIG.

[0071] Next, it is determined whether the inspection result is pass or not, and if the inspection result is pass, the curing device 800 attached to the robot 200C is moved onto the coating film 42. Then, as shown in Fig. 12, the coating film 42 is cured by the curing device 800. As a result, a cured film 44 similar to that shown in Fig. 8 is obtained. In the second embodiment as described above, the same effects as in the first embodiment can be obtained.

[0072] Furthermore, in the second embodiment, the timing of inspecting the coating film 42 and the timing of curing the coating film 42 can be freely adjusted. Therefore, for example, it is possible to wait for the ejected ink 40 to wet and spread before inspecting or curing it. This makes it possible to inspect or curing the ink 40 according to the characteristics of the ink 40, and to form a higher quality cured film 44.

[0073] Furthermore, any two of the ink ejection head 400, the inspection device 500, and the curing device 800 may be attached to one robot, and the remaining one may be attached to another robot.

[0074] 3. Third embodiment Next, a printing method, a print head unit, and a robot system according to a third embodiment will be described.

[0075] Fig. 13 is a flowchart illustrating a printing method according to the third embodiment. Fig. 14 is a side view showing a partial configuration of a print head unit 10 and a robot system 100 used in the printing method shown in Fig. 13.

[0076] The third embodiment will be described below, focusing on the differences from the first embodiment and omitting the description of the similarities. Note that in Fig. 13 and Fig. 14, the same reference numerals are used for the same configurations as the first embodiment.

[0077] The printing method according to the third embodiment is similar to the printing method according to the first embodiment, except that it includes a temporary curing step S120. Moreover, the print head unit 10 and robot system 100 according to the third embodiment are similar to the print head unit 10 and robot system 100 according to the first embodiment, except that they are provided with a temporary curing device 850.

[0078] The printing method shown in Fig. 13 includes a provisional curing step S120 provided between the ink ejection step S102 and the inspection step S104 in addition to the steps shown in Fig. 4. In the provisional curing step S120, the ink 40 ejected onto the printing surface Q1, i.e., the coating film 42 formed on the printing surface Q1, is provisionally cured. The provisional curing is performed using a provisional curing device 850 shown in Fig. 14.

[0079] The provisionally cured device 850 shown in FIG. 14 is similar to the curing device 800 shown in FIG. 3, except that the cumulative light amount of the ultraviolet light to be irradiated is set to be less than the cumulative light amount of the ultraviolet light irradiated by the curing device 800. Since the cumulative light amount of the ultraviolet light is set to be less, even if the provisionally cured device 850 irradiates the coating film 42 with ultraviolet light, the coating film 42 does not harden and remains in a provisionally cured (semi-cured) state. The provisionally cured coating film 42 can be removed in the ink removal step S108. The provisionally cured coating film 42 is less likely to spread when wet compared to the coating film 42 immediately after its formation. Therefore, the provisionally cured coating film 42 accurately reflects the landing position of the ink 40 and has a desired shape.

[0080] In the print head unit 10 shown in FIG. 14, the ink ejection head 400, the provisional curing device 850, the inspection device 500, and the curing device 800 are arranged in this order, and are scanned as a unit by the robot 200. Therefore, when the print head unit 10 is scanned in the printing direction D1 immediately after the coating film 42 is formed by the ink ejection head 400, the provisional curing device 850, the inspection device 500, and the curing device 800 move sequentially above the coating film 42. This allows the ejection of the ink 40, the provisional curing of the coating film 42, the inspection of the coating film 42, and the curing of the coating film 42 to be performed continuously. As a result, the cured film 44 with high accuracy can be continuously formed, and a highly accurate printing result can be obtained. In the third embodiment as described above, the same effects as in the first embodiment can be obtained.

[0081] 4. Effects of each embodiment As described above, the printing method according to the embodiment uses the ink ejection head 400 and the robot 200, and while the robot 200 scans the ink ejection head 400, the ink ejection head 400 ejects the ink 40 (curable ink) to print on the object Q. The robot 200 includes a robot arm 220 that supports and moves the ink ejection head 400. The printing method includes an ink ejection step S102, an inspection step S104, a determination step S106, and a curing step S110. In the ink ejection step S102, the ink ejection head 400 ejects the ink 40 toward the object Q. In the inspection step S104, the ink 40 ejected on the object Q is inspected, and the inspection result is output. In the determination step S106, it is determined whether the inspection result is pass or not. In the curing step S110, if the inspection result is pass, the ink 40 ejected on the object Q is cured.

[0082] With this configuration, even if the print result using the curable ink 40 is defective, it can be inspected before the coating film 42 is cured and corrected as necessary. This makes it possible to avoid discarding the object Q due to poor print results, reducing man-hours and costs while obtaining print results with fewer defects. As a result, it is possible to efficiently perform highly accurate printing on the object Q.

[0083] Moreover, the ink 40 (curable ink) is preferably ink that is cured by exposure to ultraviolet light UV.

[0084] UV-curable ink is an ink that cures in a short time when irradiated with UV rays, and therefore the range of wetting and spreading is particularly easy to control.

[0085] Furthermore, the above-mentioned inspection result may include a two-dimensional image obtained by capturing an image of the ink 40 (curable ink) ejected onto the object Q. In this case, it is preferable that the judgment step S106 (a step for judging whether the inspection result is pass or not) includes a process for judging whether the two-dimensional image satisfies a pass criterion and determining that the image is pass if the criterion is satisfied.

[0086] The two-dimensional image can be used to inspect the position and shape of the ink 40 ejected onto the object Q. Therefore, template matching can be performed on the pattern formed by the position and shape of the ink 40. This makes it possible to more easily and accurately determine whether the inspection result is pass or fail.

[0087] Furthermore, the above-mentioned inspection result may include color information acquired from the ink 40 (curable ink) ejected onto the object Q. In this case, the judgment step S106 (a step for judging whether the inspection result is pass or not) preferably includes a process for judging whether the color information satisfies a pass criterion and determining that the color information is pass if it is satisfied.

[0088] The color information can include in the inspection results the color of the ink 40 ejected onto the target object Q. This can prevent color defects from occurring in the print results.

[0089] If the above-mentioned test result is negative, the method may include an ink removal step S108 for removing the ink 40 (curable ink) ejected onto the target Q.

[0090] According to this configuration, it is possible to remove the rejected ink 40 and regenerate the object Q. This makes it possible to prevent the object Q from being wasted unnecessarily.

[0091] Furthermore, the printing method according to the embodiment includes, as necessary, a provisional curing step S120. The provisional curing step S120 is performed before the inspection step S104 (a step of outputting the inspection result), and provisionally cures the ink 40 (curable ink) ejected onto the target Q.

[0092] According to this configuration, a provisionally cured coating film 42 is obtained that is less likely to spread when wet compared to the coating film 42 immediately after formation. The provisionally cured coating film 42 accurately reflects the landing position of the ink 40 and has the desired shape. The provisionally cured coating film 42 can be removed in the ink removal step S108.

[0093] Moreover, the print head unit 10 according to the embodiment is supported by a robot arm 220 and scans an object Q to perform printing. The print head unit 10 comprises an attachment unit 11, an ink ejection head 400, an inspection device 500, and a curing device 800. The attachment unit 11 is attached to the robot arm 220. The ink ejection head 400 ejects ink 40 (curable ink). The inspection device 500 inspects the ejected ink 40. The curing device 800 cures the ejected ink 40.

[0094] With this configuration, a print head unit 10 can be obtained that can be applied to a printing method in which, even if the print result using the ink 40 is defective, the coating film 42 is inspected before being cured and corrected as necessary. This makes it possible to avoid discarding the object Q due to print defects, and to obtain print results with fewer defects while reducing labor and costs. As a result, it is possible to efficiently perform printing on the object Q with high precision.

[0095] Moreover, it is preferable that the ink ejection head 400, the inspection device 500, and the curing device 800 are arranged in this order.

[0096] Such print head units 10 are scanned as a unit, so that it is possible to continuously eject the ink 40, inspect the coating film 42, and harden the coating film 42. This makes it possible to continuously form a highly accurate hardened film 44, thereby obtaining highly accurate printing results.

[0097] The robot system 100 according to the embodiment is a robot system that performs printing on an object Q, and includes an ink ejection head 400, a robot 200, an inspection device 500, a curing device 800, and a control device 900. The ink ejection head 400 ejects ink 40 (curable ink). The robot 200 includes a robot arm 220 that supports and moves the ink ejection head 400. The inspection device 500 inspects the ejected ink 40. The curing device 800 cures the ejected ink 40. The control device 900 controls the operations of the ink ejection head 400, the robot 200, the inspection device 500, and the curing device 800 to perform printing. The control device 900 also includes an inspection result acquisition unit 914, a determination unit 916, and a curing processing unit 918. The inspection result acquisition unit 914 acquires the inspection result output from the inspection device 500. The determination unit 916 determines whether the inspection result is acceptable or not. If the test result is a pass, the curing processing unit 918 causes the curing device 800 to cure the ink 40 .

[0098] With this configuration, it is possible to realize a robot system 100 that can inspect the printing result using the ink 40, which is a curable ink, before curing the coating film 42, and correct it as necessary, even if the printing result is defective. By using such a robot system 100, it is possible to avoid discarding the object Q due to printing defects, and to obtain printing results with fewer defects while reducing labor and costs. Furthermore, it is possible to efficiently perform printing on the object Q with high accuracy.

[0099] The printing method, print head unit, and robot system of the present invention have been described above based on the illustrated embodiments, but the printing method, print head unit, and robot system of the present invention are not limited to the above embodiments. For example, the printing method of the present invention may be one in which any desired process or operation is added to the above embodiments. Furthermore, the print head unit and robot system of the present invention may be one in which the parts of the above embodiments are replaced with any configuration having the same function, or any configuration may be added to the above embodiments. [Explanation of symbols]

[0100] 10...print head unit, 11...mounting portion, 40...ink, 42...coating film, 44...cured film, 46...cured film, 100...robot system, 200...robot, 200A...robot, 200B...robot, 200C...robot, 210...base, 220...robot arm, 221...arm, 222...arm, 223...arm, 224...arm, 225...arm, 226...arm, 230...arm drive mechanism, 300...moving stage, 310...base, 320...stage, 320X...X stage, 320Y...Y stage, 330...moving mechanism, 330X...X moving mechanism, 330Y...Y moving mechanism, 340...piezoelectric actuator, 400...ink ejection head, 411...ink ejection hole, 420...print controller, 500...inspection device, 510...imaging unit , 600... robot controller, 610... arm control unit, 620... moving stage controller, 630... memory unit, 700... fixing member, 800... curing device, 810... ultraviolet irradiation unit, 850... temporary curing device, 900... control device, 910... print control unit, 912... print data generation unit, 914... inspection result acquisition unit, 916... judgment unit, 918... curing processing unit, 930... memory unit, D1... print direction, D2... orthogonal direction, E... encoder, J1... joint, J2... joint, J3... joint, J4... joint, J5... joint, J6... joint, M... motor, Q... object, Q1... printing surface, S102... ink ejection step, S104... inspection step, S106... judgment step, S108... ink removal step, S110... curing step, S120... temporary curing step, UV... ultraviolet light

Claims

1. A printing method that uses an ink ejection head and a robot equipped with a robotic arm for supporting and moving the ink ejection head, wherein the robot scans the ink ejection head, causing the ink ejection head to eject curable ink and print on an object, The steps include: the ink ejection head ejecting the curable ink toward the object; The steps include: inspecting the curable ink dispensed onto the object and outputting the inspection result; A step of determining whether the aforementioned test result is a pass or fail, If the inspection result is satisfactory, the step of curing the curable ink dispensed onto the object, A printing method characterized by including the following.

2. The printing method according to claim 1, wherein the curable ink is an ink that hardens upon irradiation with ultraviolet light.

3. The inspection results include a two-dimensional image obtained by imaging the curable ink dispensed onto the object, The printing method according to claim 1 or 2, wherein the step of determining whether the inspection result is acceptable includes a process of determining whether the two-dimensional image meets the acceptance criteria, and if so, determining that it is acceptable.

4. The printing method according to claim 3, wherein the step of determining whether the inspection result is acceptable includes a process of determining whether the pattern consisting of the position or shape of the ejected curable ink included in the two-dimensional image matches a pre-registered pattern.

5. The inspection results include color information obtained from the curable ink dispensed onto the object, The printing method according to claim 1 or 2, wherein the step of determining whether the inspection result is acceptable includes a process of determining whether the color information meets the acceptance criteria, and if so, determining that it is acceptable.

6. The printing method according to claim 5, wherein the step of determining whether the inspection result is acceptable includes a process of determining whether the color difference between the color information and the reference color is within a predetermined range.

7. The printing method according to claim 1 or 2, wherein in the step of determining whether the inspection result is acceptable or not, if the inspection result is determined to be unacceptable, the curable ink discharged onto the object is not cured.

8. The printing method according to claim 1 or 2, further comprising the step of removing the curable ink discharged onto the object if, in the step of determining whether the inspection result is acceptable or not, the inspection result is determined to be unacceptable.

9. The printing method according to claim 1 or 2, wherein the inspection step and the curing step are repeatedly performed for each predetermined range set in the print data.

10. The printing method according to claim 1 or 2, further comprising the step of pre-curing the curable ink dispensed onto the object before the step of outputting the inspection results.

11. A print head unit supported by a robotic arm that performs printing by scanning an object, A mounting part that is attached to the robot arm, An ink ejection head that ejects curable ink, An inspection device for inspecting the discharged curable ink, A curing device for curing the dispensed curable ink, A print head unit characterized by having the following features.

12. The print head unit according to claim 11, wherein the ink ejection head, the inspection device, and the curing device are arranged in this order.

13. A robotic system that prints on an object, An ink ejection head that ejects curable ink, A robot equipped with a robotic arm that supports and moves the ink ejection head, An inspection device for inspecting the discharged curable ink, A curing device for curing the dispensed curable ink, A control device that controls the operation of the ink ejection head, the robot, the inspection device, and the curing device to perform the printing, Equipped with, The control device is An inspection result acquisition unit that acquires the inspection results output from the aforementioned inspection device, A determination unit that determines whether the inspection result is a pass or fail, If the inspection result is satisfactory, a curing processing unit is provided to cause the curing device to cure the curable ink, A robot system characterized by having the following features.

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