Printing method and robot system

Abstract

The invention provides a printing method and a robot system, which can restrain reduction of printing quality. The printing method performs printing on an object to be printed using a print head provided in a first robot, and vibrates at least one of the print head and the object to be printed so that relative vibration between the print head and the object to be printed becomes small. The printing head and the object to be printed are moved relative to each other while the printing head and the object to be printed are moved relative to each other. In addition, vibration of either the print head or the object to be printed is detected, and the printing is performed while vibrating at least one of the print head and the object to be printed.

Description

Technical Field

[0001] The invention relates to a printing method and a robotic system. Background Art

[0002] The robot system described in Patent Document 1 includes a print head mounted at a front end, and in the robot system, the print head is moved along a print track by operating the robot, and ink is ejected from the print head toward a print object, thereby printing on the print object.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2013-202781

[0004] However, in the robot system of Patent Document 1, when the print head and the printed object vibrate relative to each other, that is, when a relative displacement other than the movement of the print head along the printing track occurs between the print head and the printed object, even if the print head is moved along the printing track, the printing will become blurred, resulting in reduced quality. Summary of the invention

[0005] The printing method of the present invention is a printing method for printing a printing object using a printing head possessed by a first robot, and the printing is performed by vibrating at least one of the printing head and the printing object while moving the printing head and the printing object relative to each other in a manner that reduces the relative vibration between the printing head and the printing object.

[0006] The robot system of the present invention has a first robot, which has a printing head for printing on a printing object. The printing is performed by vibrating at least one of the printing head and the printing object and moving the printing head relative to the printing object in a manner that reduces relative vibration between the printing head and the printing object. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 It is an overall diagram of the robot system according to the first embodiment.

[0008] Figure 2 This is a schematic diagram showing the state of a printing job.

[0009] Figure 3 It is a top view showing the first vibration generating device.

[0010] Figure 4 It is a top view showing the detection element.

[0011] Figure 5 It is a top view showing the second vibration generating device.

[0012] Figure 6 It is a diagram showing the state of vibration transmission.

[0013] Figure 7 It is an overall diagram of a robot system according to a third embodiment.

[0014] Figure 8 It is an overall diagram of a robot system according to a fourth embodiment.

[0015] Description of Reference Numerals

[0016] 1…Robot system; 10…Placing table; 2…Holding device; 2A…Second robot; 20…Holding part; 21…Placing part; 22…Claw; 23…Claw; 28…Second vibration-damping member; 3…First robot; 30…Robot body; 31…Base; 32…Robot arm; 321…Arm; 322…Arm; 323…Arm; 324…Arm; 325…Arm; 326…Arm; 38…First vibration-damping member; 39…Printing head; 4…First vibration-generating device; 40…Base; 400… piezoelectric actuator; 41… first workbench; 42… second workbench; 43… third workbench; 44… fourth workbench; 45… first workbench drive unit; 46… second workbench drive unit; 47… third workbench drive unit; 48… fourth workbench drive unit; 5… first vibrator; 51… housing; 52… acceleration sensor unit; 52x… acceleration sensor; 52y… acceleration sensor; 52z… acceleration sensor; 53… control IC; 54… detection element ; 541…substrate structure; 541a…base; 541b…movable part; 542…quartz vibration element; 542a…vibration beam; 542b…vibration beam; 543…hammer; 6…second vibration generating device; 60…base; 61…first workbench; 62…second workbench; 63…third workbench; 64…fourth workbench; 65…first workbench driving unit; 66…second workbench driving unit; 67…third workbench driving unit; 68…fourth workbench driving unit; 7… 2. Vibration meter; 71…housing; 72…acceleration sensor unit; 72x…acceleration sensor; 72y…acceleration sensor; 72z…acceleration sensor; 73…control IC; 80…robot body; 81…base; 82…robot arm; 9…control device; J1…joint; J2…joint; J3…joint; J4…joint; J5…joint; J6…joint; Q…printing track; V1…vibration; V2…vibration; V3…vibration; V4…vibration; W…printing object. DETAILED DESCRIPTION

[0017] Hereinafter, the printing method and the robot system of the present invention will be described in detail based on the embodiments shown in the drawings.

[0018] First embodiment

[0019] Figure 1 It is an overall diagram of the robot system according to the first embodiment. Figure 2 This is a schematic diagram showing the state of a printing job. Figure 3 It is a top view showing the first vibration generating device. Figure 4 It is a top view showing the detection element. Figure 5 It is a top view showing the second vibration generating device. Figure 6 It is a diagram showing the state of vibration transmission.

[0020] Figure 1 The robot system 1 shown has: a holding device 2 for holding a printing object W; a first robot 3 for printing the printing object W held by the holding device 2; and a control device 9 for controlling the driving of the holding device 2 and the first robot 3. It should be noted that in the illustrated structure, the holding device 2 and the first robot 3 are both fixed to a mounting table 10, but this is not limited to this, and they can also be fixed to different mounting tables respectively. In addition, at least one of the holding device 2 and the first robot 3 can also be fixed to a place other than the mounting table such as the ground or a wall. In addition, it is also possible that at least one of the first robot 3 and the holding device 2 is not fixed and can be self-supporting. In addition, the printing object W is a bowl-shaped object with a curved printed surface, but the shape of the printing object W is not particularly limited. Below, each part constituting the robot system 1 is described in turn.

[0021] First Robot 3

[0022] The first robot 3 includes: a robot body 30; a print head 39 mounted on the front end of the robot body 30; a first vibration generating device 4 disposed between the robot body 30 and the print head 39; and a first vibrometer 5 for detecting the vibration of the print head 39. It should be noted that, hereinafter, for the sake of convenience, the robot coordinate system set on the base 31 of the robot body 30 is represented by the X-axis, the Y-axis, and the Z-axis, and the tool coordinate system set on the front end of the robot arm 32 is represented by the x-axis, the y-axis, and the z-axis. The tool coordinate system can be converted into the robot coordinate system based on the position and posture of the print head 39 obtained from the output of the encoder provided in each joint J1 to J6.

[0023] The robot body 30 is a six-axis vertical multi-joint robot with six drive axes, and has a base 31 fixed to the mounting table 10 and a robot arm 32 rotatably connected to the base 31. In addition, the robot arm 32 is a structure in which six arms 321, 322, 323, 324, 325, and 326 are rotatably connected in this order from the side of the base 31, and has six joints J1 to J6. Among them, joints J2, J3, and J5 are bending joints, respectively, and joints J1, J4, and J6 are torsion joints, respectively. In addition, motors and encoders are respectively provided at joints J1, J2, J3, J4, J5, and J6, and the motors are driven by servo control of the output of the feedback encoder.

[0024] However, the configuration of the robot body 30 is not particularly limited. For example, the number of arms provided in the robot arm 32 is not limited to six. In addition, the robot body 30 may be a dual-arm robot, a horizontal multi-joint robot (SCARA robot), or the like.

[0025] The print head 39 is disposed at the front end of the robot arm 32, that is, the arm 326. The print head 39 is not particularly limited, but an inkjet head is used in this embodiment. The inkjet head has an ink chamber (not shown), a vibration plate disposed on the wall of the ink chamber, and an ink ejection hole connected to the ink chamber. The ink in the ink chamber is ejected from the ink ejection hole by the vibration of the vibration plate. Then, as shown in FIG. Figure 2 As shown, printing is performed by ejecting ink from the print head 39 onto the printed surface while the print head 39 is moved relative to the printing object W at a predetermined printing trajectory Q and speed by the robot arm 32 .

[0026] The first vibration generating device 4 is disposed between the arm 326 and the print head 39. The first vibration generating device 4 is a device for applying vibration to the print head 39. Figure 3 As shown, the first vibration generating device 4 comprises: a base 40, supported by an arm 326; a first worktable 41, movable in the x-axis direction relative to the base 40; a second worktable 42, movable in the y-axis direction relative to the first worktable 41; a third worktable 43, movable in the z-axis direction relative to the second worktable 42; and a fourth worktable 44, rotatable around the z-axis relative to the third worktable 43, and a printing head 39 is arranged on the fourth worktable 44.

[0027] Therefore, when the first stage 41 moves in the x-axis direction, the print head 39 vibrates in the x-axis direction, when the second stage 42 moves in the y-axis direction, the print head 39 vibrates in the y-axis direction, when the third stage 43 moves in the z-axis direction, the print head 39 vibrates in the z-axis direction, and when the fourth stage 44 rotates around the z-axis, the print head 39 vibrates around the z-axis. By appropriately combining these four vibrations, the print head 39 can be vibrated in various sizes and directions.

[0028] In addition, the first vibration generating device 4 has: a first worktable driving unit 45, which moves the first worktable 41 relative to the base 40; a second worktable driving unit 46, which moves the second worktable 42 relative to the first worktable 41; a third worktable driving unit 47, which moves the third worktable 43 relative to the second worktable 42; and a fourth worktable driving unit 48, which moves the fourth worktable 44 relative to the third worktable 43.

[0029] The first, second, third, and fourth workbench drive units 45, 46, 47, and 48 are respectively equipped with piezoelectric actuators 400 driven by the expansion and contraction of piezoelectric elements caused by energization, and the first, second, third, and fourth workbenches 41, 42, 43, and 44 are moved by transmitting the vibration of the piezoelectric actuators 400 to them. By using the piezoelectric actuators 400, the movement amount and movement speed of the first, second, third, and fourth workbench drive units 45, 46, 47, and 48 can be finely and accurately controlled, and the switching of the movement direction also becomes agile. In addition, the miniaturization and lightweight of the first vibration generating device 4 can also be achieved. Therefore, the increase in the weight of the front end of the robot body 30 can be suppressed, so that the reduction in the driving characteristics such as the responsiveness and vibration reduction of the robot body 30 can be effectively suppressed.

[0030] The first vibration generating device 4 is described above, but the configuration of the first vibration generating device 4 is not particularly limited. For example, the number of workbenches that move relative to the base 40 is not particularly limited, and may be less than three or more than five. In addition, the first, second, third, and fourth workbench drive units 45, 46, 47, and 48 may also be configured using a drive source other than the piezoelectric actuator 400, such as a motor that rotates when energized. In addition, as long as the print head 39 can be vibrated, the configuration of the first vibration generating device 4 is not particularly limited, and may be configured, for example, between the robot body 30 and the mounting table 10.

[0031] The first vibrometer 5 is disposed on the printing head 39 to detect the vibration of the printing head 39. It should be noted that the "vibration" means displacement other than displacement along the printing track Q described later. Such a first vibrometer 5 is a three-axis acceleration sensor, such as Figure 3 As shown, a rectangular parallelepiped housing 51 and an acceleration sensor unit 52 and a control IC 53 accommodated in the housing 51 are provided.

[0032] The size of the housing 51 is not particularly limited, but for example, the width×depth×height is preferably 62.4 mm×46.2 mm×36.2 mm or less. In addition, the weight of the housing 51 is not particularly limited, but for example, it is preferably 100 g or less. As a result, the first vibrator 5 becomes sufficiently small and light, and the degree of freedom of configuration of the first vibrator 5 increases. In addition, the increase in the weight of the front end of the robot body 30 can be suppressed, so that the reduction in the responsiveness, vibration damping, etc. of the robot body 30 can be effectively suppressed.

[0033] The acceleration sensor unit 52 includes an acceleration sensor 52x for detecting acceleration in the x-axis direction, an acceleration sensor 52y for detecting acceleration in the y-axis direction, and an acceleration sensor 52z for detecting acceleration in the z-axis direction. Figure 4 The detection element 54 is shown.

[0034] The detection element 54 has a substrate structure 541 and a quartz vibration element 542 and a hammer 543 fixed to the surface of the substrate structure 541. The substrate structure 541 is formed of a quartz substrate, and has a base 541a and a movable portion 541b extending from the base 541a. In addition, the hammer 543 is arranged at the front end of the movable portion 541b. In addition, the quartz vibration element 542 is a double tuning fork type quartz vibration element formed by a quartz substrate, one end of which is fixed to the base 541a, and the other end is fixed to the movable portion 541b. In addition, although not shown in the figure, each vibration beam 542a, 542b of the quartz vibration element 542 is arranged with a pair of excitation electrodes, and when an AC voltage is applied between these excitation electrodes, the two vibration beams 542a, 542b perform bending vibration in a manner of repeatedly approaching and moving away from each other.

[0035] When acceleration in the thickness direction is applied to such a detection element 54, the movable portion 541b is bent, thereby applying tensile stress or compressive stress to the quartz vibration element 542. The resonance frequency of the quartz vibration element 542 changes according to the magnitude of the applied stress. Therefore, acceleration can be detected based on the change in the resonance frequency of the quartz vibration element 542.

[0036] In the acceleration sensor 52x, the thickness direction of the detection element 54 is consistent with the x-axis direction, in the acceleration sensor 52y, the thickness direction of the detection element 54 is consistent with the y-axis direction, and in the acceleration sensor 52z, the thickness direction of the detection element 54 is consistent with the z-axis direction. Therefore, the accelerations in the x-axis, y-axis, and z-axis directions can be detected by the acceleration sensors 52x, 52y, and 52z, respectively. Here, since the quartz vibration element 542 has excellent frequency-temperature characteristics compared to elements formed of other piezoelectric materials and elements formed of silicon, which is a material commonly used as a sensor element like quartz, temperature compensation can be performed with good accuracy. In addition, since it is a circuit that measures frequency changes, analog elements can be excluded and noise is also small. Therefore, the vibration of the print head 39 can be detected with good accuracy.

[0037] In addition, the control IC 53 is, for example, an MCU (Micro Controller Unit), which has a control circuit for controlling the driving of the acceleration sensor unit 52 and an interface circuit for communicating with the outside. Among them, the control circuit drives the acceleration sensors 52x, 52y, and 52z, and detects the acceleration in each axis direction based on the resonance frequency of the quartz vibration element 542 possessed by the acceleration sensors 52x, 52y, and 52z. On the other hand, the interface circuit sends and receives signals with the control device 9, receives instructions from the control device 9, or outputs the detected acceleration information to the control device 9. Here, the control IC 53 sends and receives signals with the control device 9 wirelessly. As a result, since the lead of the signal line is not required, the installation of the first vibration meter 5 becomes easy, and the degree of freedom of the installation position is also improved. As a wireless communication standard, there is no particular limitation, and Wi-Fi, Bluetooth (registered trademark), etc. can be used, but Bluetooth is used in this embodiment. As a result, power saving can be achieved.

[0038] The maximum sampling rate of such a first vibrometer 5 is not particularly limited, but is preferably above 1000 Hz. Thus, each acceleration can be acquired at a sufficiently high rate, so that the vibration of the print head 39 can be detected with high precision. In addition, the noise density of the first vibrometer 5 is not particularly limited, but is preferably below 0.2 μG / √Hz. Thus, the noise is sufficiently suppressed, and the vibration of the print head 39, especially the low-frequency vibration, can be detected with high precision. In particular, since the vibration generated in the print head 39 during printing is about several Hz to tens of Hz, this characteristic is more significantly exerted. It should be noted that the noise density is expressed as the average value of the noise density at 25°C and 0.5 Hz to 6 Hz in Typ. value. In addition, the maximum measurement frequency of the first vibrometer 5 is preferably above 460 Hz. Thus, the frequency band of the vibration that may be generated in the print head 39 can be fully covered, so that the vibration of the print head 39 can be detected with high precision.

[0039] The first vibrator 5 has been described above, but the configuration of the first vibrator 5 is not particularly limited as long as the vibration of the print head 39 can be detected. For example, the detection element 54 of the acceleration sensors 52x, 52y, and 52z may be a silicon MEMS. The silicon MEMS may be configured as follows: a fixed electrode and a movable electrode in a comb-shaped manner that are arranged to mesh with each other, and acceleration is detected based on a change in electrostatic capacitance between the fixed electrode and the movable electrode caused by the displacement of the movable electrode relative to the fixed electrode due to the acceleration received. In addition, as long as the vibration of the print head 39 can be detected, the configuration of the first vibrator 5 is not particularly limited, and for example, it may be configured on the fourth workbench 44 of the first vibration generating device 4.

[0040] Holding device 2

[0041] like Figure 1 As shown, the holding device 2 includes a holding portion 20 for holding the print object W, a second vibration generating device 6 for vibrating the holding portion 20 , and a second vibration meter 7 for detecting vibration of the print object W.

[0042] The holding portion 20 includes a placing portion 21 for placing the print object W, and a pair of claws 22 and 23 for clamping and fixing the print object W. However, as long as the print object W can be held, the structure of the holding portion 20 is not particularly limited, and can be appropriately designed according to the shape of the print object W, the position of the printed surface, etc.

[0043] The second vibration generating device 6 is disposed between the holding portion 20 and the mounting table 10. The second vibration generating device 6 is a device for applying vibration to the printing object W. The second vibration generating device 6 has the same structure as the first vibration generating device 4. Figure 5As shown, it has: a base 60 fixed to the mounting table 10; a first worktable 61, which moves in the X-axis direction relative to the base 60; a second worktable 62, which moves in the Y-axis direction relative to the first worktable 61; a third worktable 63, which moves in the Z-axis direction relative to the second worktable 62; a fourth worktable 64, which rotates around the Z-axis relative to the third worktable 63; a first worktable driving unit 65, which moves the first worktable 61 relative to the base 60; a second worktable driving unit 66, which moves the second worktable 62 relative to the first worktable 61; a third worktable driving unit 67, which moves the third worktable 63 relative to the second worktable 62; and a fourth worktable driving unit 68, which moves the fourth worktable 64 relative to the third worktable 63. In addition, a holding unit 20 is arranged on the fourth worktable 64. It should be noted that since these parts are the same as the first vibration generating device 4 described above, their description is omitted.

[0044] The second vibration generating device 6 is described above, but the configuration of the second vibration generating device 6 is not particularly limited. In addition, the second vibration generating device 6 may be configured differently from the first vibration generating device 4. In addition, as long as the printing object W can be vibrated, the configuration of the second vibration generating device 6 is not particularly limited.

[0045] like Figure 2 As shown, the second vibrometer 7 is arranged in the holding portion 20 to detect the vibration of the printing object W. The second vibrometer 7 is the same as the first vibrometer 5 described above. That is, the second vibrometer 7 is a three-axis acceleration sensor, which has a rectangular housing 71 and an acceleration sensor unit 72 and a control IC 73 accommodated in the housing 71. In addition, the acceleration sensor unit 72 has an acceleration sensor 72x for detecting acceleration in the X-axis direction, an acceleration sensor 72y for detecting acceleration in the Y-axis direction, and an acceleration sensor 72z for detecting acceleration in the Z-axis direction. It should be noted that since these parts are the same as the first vibrometer 5 described above, their description is omitted.

[0046] The second vibrometer 7 has been described above, but the configuration of the second vibrometer 7 is not particularly limited as long as the vibration of the printing object W can be detected. In addition, the second vibrometer 7 may be a configuration different from that of the first vibrometer 5. In addition, the configuration of the second vibrometer 7 is not particularly limited as long as the vibration of the printing object W can be detected. For example, the second vibrometer 7 may be directly configured on the printing object W. However, when the second vibrometer 7 is directly configured on the printing object W, the vibration of the printing object W can be detected with better accuracy. However, on the other hand, each time the printing is completed and a new printing object W is set on the holding portion 20, the second vibrometer 7 needs to be replaced and calibrated, etc., resulting in poor workability. Therefore, in the present embodiment, the second vibrometer 7 is configured on the holding portion 20 to achieve a balance between workability and accuracy.

[0047] Control device 9

[0048] The control device 9 controls the driving of the first robot 3 and the holding device 2. The control device 9 is constituted by, for example, a computer, and has a processor (CPU) for processing information, a memory connected to the processor in a communicable manner, and an external interface for connecting to an external device. The memory stores various programs that can be executed by the processor, and the processor can read and execute the programs stored in the memory.

[0049] The configuration of the robot system 1 has been described above. Next, a printing method for printing on a printing object W using the robot system 1 will be described.

[0050] Printing method

[0051] As described above, printing using the robot system 1 is performed by moving the print head 39 along the printed surface of the printing object W at a predetermined printing track Q and speed while ejecting ink from the print head 39 to the printed surface. However, during printing, when relative vibration occurs between the print head 39 and the printing object W, that is, when displacement other than the movement of the print head 39 along the printing track Q occurs between the print head 39 and the printing object W, the actual track of the print head 39 relative to the printing object W deviates from the printing track Q, resulting in reduced printing quality. It should be noted that the relative vibration between the print head 39 and the printing object W is also referred to as "relative vibration" below.

[0052] Relative vibration occurs, for example, as follows. Figure 6As shown, the vibration V1 is generated in the printing head 39 by driving the robot body 30. Then, the vibration V1 is transmitted to the mounting table 10 via the robot body 30, thereby generating a vibration V2 in the mounting table 10, and further, the vibration V2 is transmitted to the holding device 2, thereby generating a vibration V3 in the holding device 2. Then, a vibration V4 in which the vibrations V2 and V3 are superimposed is generated in the printing object W. In this way, different vibrations V1 and V4 are generated between the printing head 39 and the printing object W, and relative vibration occurs.

[0053] Therefore, in the printing method using the robot system 1, the relative vibration is detected, and printing is performed while vibrating at least one of the robot arm 32, the print head 39, and the printing object W in a manner that reduces the detected relative vibration, preferably in a manner that eliminates it. As a result, compared with the case where the robot arm 32 is not vibrated, the deviation between the actual track of the print head 39 relative to the printing object W and the printing track Q is reduced, and the printing object W can be printed with high precision. Therefore, the reduction in printing quality can be effectively suppressed. It should be noted that "detecting relative vibration" means finding the direction and magnitude of the relative vibration.

[0054] The control device 9 obtains the relative vibration based on the difference between the vibration V1 of the print head 39 and the vibration V4 of the print object W. Specifically, in the robot system 1, the vibration V1 of the print head 39 is obtained using the first vibrometer 5, the vibration V4 of the print object W is obtained using the second vibrometer 7, and the relative vibration is obtained based on the difference between the obtained vibrations V1 and V4. According to such a method, the relative vibration can be easily detected. In particular, since the first vibrometer 5 is arranged on the print head 39 and the second vibrometer 7 is arranged on the holding portion 20, the relative vibration can be detected with good accuracy. However, the detection method of the relative vibration is not particularly limited.

[0055] In addition, the control device 9 drives at least one of the mechanical arm 32, the first vibration generating device 4, and the second vibration generating device 6 to apply a cancelling vibration to at least one of the print head 39 and the printing object W so that the relative vibration becomes smaller or preferably disappears. The "cancelling vibration" is not particularly limited as long as it can cancel at least a part of the relative vibration, but is preferably a vibration in the opposite phase to the relative vibration. Thus, in theory, all the relative vibrations are canceled, and the relative vibrations disappear. Therefore, the reduction in printing quality can be more effectively suppressed.

[0056] The methods for applying cancelling vibrations include: (a) driving the robot arm 32 to apply cancelling vibrations to the print head 39; (b) driving the first vibration generating device 4 to apply cancelling vibrations to the print head 39; (c) driving the second vibration generating device 6 to apply cancelling vibrations to the printing object W; (d) driving the robot arm 32 and the first vibration generating device 4 to apply cancelling vibrations to the print head 39; (e) driving the robot arm 32 and the second vibration generating device 6 to apply cancelling vibrations between the print head 39 and the printing object W; (f) driving the first vibration generating device 4 and the second vibration generating device 6 to apply cancelling vibrations between the print head 39 and the printing object W; (g) driving all of the robot arm 32, the first vibration generating device 4 and the second vibration generating device 6 to apply cancelling vibrations between the print head 39 and the printing object W. One of these methods can be selected for execution. In the cases (e) to (g) above, the print head 39 and the print object W may be vibrated so that the vibrations of the print head 39 and the print object W are combined to cancel each other out.

[0057] According to such a method, at least a part of the relative vibration disappears due to the offsetting vibration, and the relative vibration becomes smaller than when the offsetting vibration is not applied. As a result, the deviation of the print head 39 from the actual track of the printing object W and the printing track Q is reduced, and the reduction in printing quality can be effectively suppressed. In particular, since the printing object W can be stationary when only the printing head 39 is offset by the vibration as in (a), (b), and (d), the deviation and separation of the printing object W relative to the holding device 2 can be suppressed. On the other hand, since when only the printing object W is vibrated as in (c), the print head 39 can be prevented from performing any movement other than moving along the printing track Q, the driving of the first robot 3 becomes smooth. Therefore, in either case, the reduction in printing quality can be effectively suppressed.

[0058] In addition, when two or more of the mechanical arm 32, the first vibration generating device 4 and the second vibration generating device 6 including the mechanical arm 32 are used to apply canceling vibrations as in (d), (e) and (g), it is preferably set as follows. Relative vibrations include low-frequency relative vibrations less than a specified frequency and high-frequency relative vibrations exceeding a specified frequency. It should be noted that the specified frequency is not particularly limited, but is, for example, about 10 Hz. In addition, compared with the first and second vibration generating devices 4 and 6, the mechanical arm 32 is heavy and has correspondingly poor responsiveness.

[0059] Therefore, in (d), low-frequency cancelling vibrations that cancel low-frequency relative vibrations are applied to the print head 39 by driving the robot 32, and high-frequency cancelling vibrations that cancel high-frequency relative vibrations are applied to the print head 39 by driving the first vibration generating device 4. Since the low-frequency cancelling vibrations and the high-frequency cancelling vibrations become cancelling vibrations when they are combined, the relative vibrations are reduced as a whole. Similarly, in (e), low-frequency cancelling vibrations are applied to the print head 39 by driving the robot 32, and high-frequency cancelling vibrations are applied to the printed object W by driving the second vibration generating device 6. In addition, in (g), low-frequency cancelling vibrations are applied to the print head 39 by driving the robot 32, and high-frequency cancelling vibrations are applied between the print head 39 and the printed object W by driving the first and second vibration generating devices 4 and 6. In this way, by sharing the frequency bands of the cancelling vibrations generated by the robot 32 and the first and second vibration generating devices 4 and 6, it is possible to apply highly accurate cancelling vibrations without placing excessive burdens on each part.

[0060] In addition, when two or more of the robot arm 32, the first vibration generating device 4, and the second vibration generating device 6 are used to apply the cancelling vibration as in (d) to (g), the direction of the vibration can also be shared. When (f) is used as a representative example, for example, the first vibration generating device 4 can be driven to apply the first cancelling vibration to the print head 39 to cancel the vibration components in the X-axis and Y-axis directions of the relative vibration, and the second vibration generating device 6 can be driven to apply the second cancelling vibration to the printed object W to cancel the vibration component in the Z-axis direction of the cancelling vibration. This method is effective when the vibration components that can be generated by the first and second vibration generating devices 4 and 6 are different and the cancelling vibration cannot be generated by only one side. In addition, for example, the size of the vibration can also be shared. When (f) is also used as a representative example, for example, the first vibration generating device 4 can be used to apply the first cancelling vibration of 1 / 2 of the relative vibration to the print head 39, and the second vibration generating device 6 can be used to apply the second cancelling vibration of the remaining 1 / 2 of the relative vibration to the printed object W. This method is effective when the outputs of the first and second vibration generating devices 4 and 6 are insufficient and canceling vibration cannot be generated by only one of them.

[0061] Next, the timing of detecting the relative vibration is described. For example, the relative vibration can also be detected by performing a test run of the print head 39 before printing. Specifically, before printing, ink is not ejected from the print head 39, but the print head 39 is moved at the same printing track Q and speed as in actual printing, and the relative vibration at this time is detected, and the offset vibration is determined based on the detected relative vibration. Then, while applying the determined offset vibration between the print head 39 and the printing object W by any of the aforementioned methods, actual printing is performed. That is, while applying the offset vibration between the print head 39 and the printing object W and ejecting ink from the print head 39, the print head 39 is moved along the printing track Q at a specified speed, thereby printing the printing object W. According to such a method, since the offset vibration can be determined in advance, the control of the robot system 1 becomes easy.

[0062] In addition, relative vibration can also be detected during printing. Specifically, when the print head 39 starts to move along the print track Q at a specified speed for printing, the detection of relative vibration begins, and each time the latest relative vibration is detected, a canceling vibration that cancels it is determined, and the determined canceling vibration is applied between the print head 39 and the printing object W by any of the aforementioned methods. That is, the relative vibration is detected in real time during printing, and the result is fed back to the canceling vibration. In this way, according to the method of detecting relative vibration while printing, the printing operation efficiency is improved because there is no need for a prior trial run for detecting relative vibration.

[0063] The robot system 1 has been described above. As described above, the printing method performed using such a robot system 1 is a printing method for printing the printing object W using the printing head 39 provided in the first robot 3, and printing is performed by relatively moving the printing head 39 and the printing object W while vibrating at least one of the printing head 39 and the printing object W in a manner that reduces the relative vibration between the printing head 39 and the printing object W. According to such a printing method, since the relative vibration between the printing head 39 and the printing object W is suppressed, the deviation between the actual track of the printing head 39 relative to the printing object W and the printing track Q is reduced, and the printing object W can be printed with high precision. Therefore, it is possible to effectively suppress the reduction of printing quality.

[0064] In addition, as described above, in the printing method, the vibration of either the print head 39 or the print object W is detected, and printing is performed while vibrating at least one of the print head 39 and the print object W. Thus, vibration that can reduce relative vibration can be more reliably applied to the print head 39 and the print object W.

[0065] As described above, in the printing method, the relative vibration is detected by separately detecting the vibration of the print head 39 and the vibration of the printing object W. This makes it possible to easily detect the relative vibration.

[0066] As described above, in the printing method, the first vibration meter 5 for detecting the vibration of the print head 39 and the second vibration meter 7 for detecting the vibration of the printing object W are provided. Thus, since the vibration of the print head 39 and the vibration of the printing object W can be detected with high accuracy, the relative vibration can be detected with high accuracy.

[0067] As described above, in the printing method, the first vibrator 5 includes the quartz vibrator element 542. Although not shown, the second vibrator 7 also includes the same quartz vibrator element as the quartz vibrator element 542. Thus, the vibrations of the print head 39 and the printing object W can be detected with high accuracy.

[0068] As described above, in the printing method, the relative vibration may be reduced by vibrating only the print head 39 of the print object W. According to such a method, since the print object W can be made still, the deviation of the print object W can be suppressed.

[0069] As described above, in the printing method, the relative vibration can be reduced by vibrating only the print head 39 and the print object W. According to such a method, the print head 39 can be stationary during the vibration reduction operation, so the first robot 3 can be driven more smoothly.

[0070] In addition, as described above, in the printing method, printing is performed while detecting relative vibration. Thus, since the relative vibration can be detected in real time during printing and the result can be fed back, the relative vibration during printing can be reduced more reliably.

[0071] In addition, as described above, in the printing method, printing may be performed after the relative vibration is detected. According to such a method, since the relative vibration detection is only performed once before printing, control becomes easy.

[0072] In addition, as described above, the robot system 1 includes the first robot 3, and the first robot 3 includes the print head 39 for printing on the printing object W. The printing is performed by relatively moving the print head 39 and the printing object W while vibrating at least one of the print head 39 and the printing object W so as to reduce the relative vibration between the print head 39 and the printing object W. According to such a configuration, since the relative vibration between the print head 39 and the printing object W is suppressed, the deviation between the actual trajectory of the print head 39 with respect to the printing object W and the printing trajectory Q is reduced, and the printing object W can be printed with high precision. Therefore, it is possible to effectively suppress the reduction of printing quality.

[0073] Second embodiment

[0074] Except for the printing method, the robot system 1 involved in this embodiment is the same as the robot system 1 of the first embodiment described above. It should be noted that in the following description, the robot system 1 of this embodiment is described mainly with respect to the differences from the first embodiment described above, and the description of the same matters is omitted.

[0075] In the printing method of the present embodiment, the relative vibration is not detected, and the vibration of the print head 39 is offset by driving the first vibration generating device 4, and the vibration of the printing object W is offset by driving the second vibration generating device 6. Specifically, the control device 9 detects the vibration of the print head 39, that is, the print head vibration, using the first vibration meter 5, and applies the print head offset vibration that offsets the print head vibration to the print head 39 using the first vibration generating device 4. Thus, the vibration of the print head 39 can be reduced. Similarly, the control device 9 detects the vibration of the printing object W, that is, the printing object vibration, using the second vibration meter 7, and applies the printing object offset vibration that offsets the printing object vibration to the printing object W using the second vibration generating device 6. Thus, the vibration of the printing object W can be reduced. In this way, by reducing the vibration of the print head 39 and the printing object W respectively, the relative vibration is reduced. Alternatively, the vibration of one of the print head 39 and the printing object W can be detected, and the offset vibration that offsets the detected vibration can be applied to the other. Thus, the relative vibration is reduced. According to such a method, even if the relative vibration is not detected, the relative vibration can be reduced more reliably.

[0076] According to the second embodiment as described above, it is possible to achieve the same effects as those of the first embodiment described above.

[0077] Third embodiment

[0078] Figure 7 It is an overall diagram of a robot system according to a third embodiment.

[0079] The robot system 1 of this embodiment is the same as the robot system 1 of the first embodiment described above, except that the first and second vibration-generating devices 4 and 6 are replaced with the first and second vibration-damping components 38 and 28. It should be noted that in the following description, the robot system 1 of this embodiment is described mainly with respect to the differences from the first embodiment described above, and the description of the same matters is omitted. In addition, in the figures of this embodiment, the same reference numerals are given to the same components as those of the above embodiment.

[0080] like Figure 7 As shown, in the robot system 1 of the present embodiment, the first vibration generating device 4 is omitted from the first robot 3, and instead, a first vibration damping member 38 is arranged between the arm 326 and the print head 39. In addition, the second vibration generating device 6 is omitted from the holding device 2, and instead, a second vibration damping member 28 is arranged between the mounting table 10 and the holding portion 20. The first and second vibration damping members 38 and 28 are made of, for example, a rubber material, and can absorb at least a part, preferably all, of the high-frequency relative vibration included in the relative vibration. In addition, the low-frequency relative vibration included in the relative vibration that cannot be absorbed by the first and second vibration damping members 38 and 28 is offset by applying a low-frequency offset vibration to the print head 39 using the robot arm 32. According to such a configuration, for example, since it becomes a simple configuration compared with the first embodiment described above, its control becomes easy.

[0081] According to the third embodiment, the same effects as those of the first embodiment can be achieved.

[0082] Fourth embodiment

[0083] Figure 8 It is an overall diagram of a robot system according to a fourth embodiment.

[0084] The robot system 1 involved in this embodiment is the same as the robot system 1 of the first embodiment described above, except that the structure of the holding device 2 is different. It should be noted that in the following description, the robot system 1 of this embodiment is mainly described with the difference from the first embodiment described above, and the description of the same matters is omitted. In addition, in the figures of this embodiment, the same reference numerals are marked for the same structures as those in the above embodiment.

[0085] like Figure 8 As shown, the holding device 2 is a second robot 2A having a robot body 80 , a holding portion 20 disposed at the front end of the robot body 80 , a second vibration generating device 6 disposed between the robot body 80 and the holding portion 20 , and a second vibrometer 7 disposed on the holding portion 20 .

[0086] In addition, the robot body 80 is a six-axis vertical multi-joint robot, and has the same structure as the robot body 30 of the first robot 3. That is, the robot body 80 has a base 81 fixed to the mounting table 10 and a robot arm 82 rotatably connected to the base 81. In addition, a holding part 20 is arranged at the front end of the robot arm 82, a second vibration generating device 6 is arranged between the robot arm 82 and the holding part 20, and a second vibration meter 7 is arranged on the holding part 20. According to such a structure, since the position and posture of the printing object W can be changed by driving the second robot 2A, the printed surface of the printing object W can be set to a position and posture that is easy for the first robot 3 to print. Therefore, printing becomes easy.

[0087] As described above, in this embodiment, there is a holding device 2 for holding the printing object W, and the holding device 2 is the second robot 2A. According to such a configuration, since the position and posture of the printing object W can be changed by driving the second robot 2A, the printed surface of the printing object W can be set to a position and posture that is easy for the first robot 3 to print. Therefore, printing becomes easy.

[0088] According to the fourth embodiment, it is possible to achieve the same effects as those of the first embodiment described above.

[0089] The printing method and the robot system of the present invention are described above based on the illustrated embodiments, but the present invention is not limited thereto, and the configuration and process of each part can be replaced with any configuration and process having the same function. In addition, other arbitrary configurations and processes can also be added to the present invention. In addition, the various embodiments can also be appropriately combined.

Claims

1. A printing method, characterized in that: A printing method for printing a printing object using a printing head provided by a first robot. The printing is performed by relatively moving the print head and the print object while vibrating at least one of the print head and the print object so that relative vibration between the print head and the print object is reduced.

2. The printing method according to claim 1, characterized in that: The printing is performed while detecting vibration of one of the print head and the print object and vibrating at least one of the print head and the print object.

3. The printing method according to claim 1, characterized in that: The relative vibration is detected by detecting the vibration of the print head and the vibration of the printing object respectively.

4. The printing method according to claim 3, characterized in that: A first vibrometer for detecting vibration of the print head and a second vibrometer for detecting vibration of the printing object are provided.

5. The printing method according to claim 4, characterized in that: The first vibrator and the second vibrator each include a quartz crystal vibrator element.

6. The printing method according to claim 1, characterized in that: The relative vibration is reduced by vibrating only the print head out of the print head and the print object.

7. The printing method according to claim 1, characterized in that: The relative vibration is reduced by vibrating only the printing object out of the printing head and the printing object.

8. The printing method according to claim 7, characterized in that: A holding device for holding the printing object is provided, The holding device is a second robot.

9. The printing method according to claim 2 or 3, characterized in that: The printing is performed while detecting the relative vibration.

10. The printing method according to claim 2 or 3, characterized in that: The printing is performed after the relative vibration is detected.

11. A robot system, characterized in that: have: a first robot including a printing head for printing on a printing object; The printing is performed by relatively moving the print head and the print object while vibrating at least one of the print head and the print object so that relative vibration between the print head and the print object is reduced.

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