Printing method and printing system

Abstract

To solve the problem in which, when printing is performed in a plurality of tracks, teaching work for a robot needs to be performed for each path on which a printing head moves, and it is difficult to alleviate a load of an operator.SOLUTION: In a printing method, a plurality of printing patterns aligned side by side with each other is printed, while the position of a printing head with respect to an object is changed by the operation for controlling a control point of a robot along the path stored beforehand. The printing method includes: a first printing step S105 of printing a first printing pattern by an operation of moving a first control point along a path; and a second printing step S107 of printing a second printing pattern aligned with the first printing pattern by an operation of moving a second control point different from the first control point along the path in the first direction where the position with respect to the printing head crosses the path.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a printing method and a printing system. [Background technology]

[0002] Conventionally, three-dimensional object printing systems have been known that combine the movements of multiple movable parts to move an inkjet print head and print on the surface of a three-dimensional object. For example, Patent Document 1 discloses a system that prints on an object using an inkjet print head attached to the arm of a robot. The robot is configured to move the print head along the surface of the object. This allows the print head to move along multiple trajectories to form a desired print image. In this case, it is common to prepare multiple trajectories without changing the control point and move the control point along each trajectory. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-202781 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the system described in Patent Document 1, printing is performed on multiple trajectories, so the robot needs to be taught for each path the print head moves, which makes it difficult to reduce the burden on the worker. [Means for solving the problem]

[0005] A printing method according to an application example of the present invention is a printing method for printing a plurality of printing patterns that are aligned with each other while changing the position of a printing head relative to an object by controlling a control point of a robot along a pre-stored path, and is characterized by including: a first printing step for printing a first printing pattern by moving a first control point along the path; and a second printing step for printing a second printing pattern that is aligned with the first printing pattern by moving a second control point along the path, the second control point being different from the first control point in a first direction in which its position relative to the printing head intersects with the path.

[0006] A printing system according to an application example of the present invention comprises a print head, a robot that changes the relative position of the print head and an object, and a control unit that controls the operation of the print head and the robot, wherein the control unit performs a first printing in which a first print pattern is printed by moving a first control point along a path pre-stored by the robot, and performs a second printing in which a second print pattern is printed so as to be aligned with the first print pattern by moving a second control point, whose position relative to the print head is different from that of the first control point, along the path by the robot in a first direction that intersects with the path. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is an overall view showing the overall configuration of a printing system according to a first embodiment. [Figure 2] FIG. 2 is a plan view showing the print head of FIG. 1. [Figure 3] FIG. 2 is a functional block diagram of the printing system of FIG. [Figure 4] 4 is a flowchart illustrating a printing method according to the first embodiment. [Figure 5] FIG. 4 is a schematic diagram showing the position of a tool point relative to a print head. [Figure 6] FIG. 4 is a schematic diagram showing the position of a tool point relative to a print head. [Figure 7]10 is a part of a program including a command for setting a control point according to the first embodiment. [Figure 8] FIG. 2 is a diagram illustrating the paths of a print head and a tool point in a printing method according to the first embodiment. [Figure 9] FIG. 10 is a diagram illustrating the paths of a print head and a tool point in a printing method according to a second embodiment. [Figure 10] FIG. 4 is a schematic diagram showing the position of a tool point relative to a print head. [Figure 11] FIG. 4 is a schematic diagram showing the position of a tool point relative to a print head. [Figure 12] FIG. 4 is a schematic diagram showing the position of a tool point relative to a print head. [Figure 13] FIG. 10 is a schematic diagram showing the shape of an object according to the third embodiment. [Figure 14] FIG. 10 is a diagram illustrating the paths of a print head and a tool point in a printing method according to a third embodiment. [Figure 15] FIG. 10 is an overall view showing the overall configuration of a printing system according to a fourth embodiment. [Figure 16] FIG. 1 is a diagram showing a specific example of an object. DETAILED DESCRIPTION OF THE INVENTION

[0008] 1. First embodiment A printing system and a printing method according to a first embodiment will be described.

[0009] 1.1.Printing System 1 is an overall view showing the overall configuration of a printing system 1 according to a first embodiment. The printing system 1 includes a robot 2, a print head 3, a control device 4, and a teaching device 5.

[0010] The printing system 1 is a system that prints on the printing surface of the object W1 by moving the print head 3 by controlling the control point of the robot 2 along a pre-stored path CP, thereby changing the relative position between the print head 3 and the object W1.

[0011] The robot 2 is a six-axis vertical articulated robot having six drive axes. The robot 2 has a base 21 fixed to the floor and a robot arm 22 connected to the base 21. The robot arm 22 has six arms 221, 222, 223, 224, 225, and 226 rotatably connected in this order from the base 21 side. The arm 226 forms the tip surface of the robot arm 22.

[0012] However, the configuration of the robot 2 is not particularly limited. For example, the number of arms that the robot arm 22 has is not limited to six. Furthermore, the robot 2 may be a horizontal articulated robot, or a multi-arm robot having multiple robot arms 22. Furthermore, the installation position of the robot 2 may be the ceiling or wall surface of a stand.

[0013] Figure 2 is a plan view showing the print head 3 of Figure 1. In this specification, the three mutually orthogonal axes are referred to as the X-axis, Y-axis, and Z-axis. Furthermore, one direction along the X-axis is referred to as the +X direction, and the direction opposite to the +X direction is referred to as the -X direction. Similarly, opposite directions along the Y-axis are referred to as the +Y direction and the -Y direction. Furthermore, opposite directions along the Z-axis are referred to as the +Z direction and the -Z direction.

[0014] Furthermore, in this embodiment, the X-axis, Y-axis, and Z-axis are coordinate axes referred to as a tool coordinate system, with the origin being a predetermined reference position of the print head 3 attached to the robot 2. As will be described below, the X-axis is the axis along the extension direction of the print head 3, the Y-axis is the axis along the scanning direction of the print head 3, and the Z-axis is the axis along the direction in which the print head 3 and arm 226 are aligned. Furthermore, for the Z-axis, the direction from the print head 3 towards the arm 226 is the +Z direction.

[0015] In this embodiment, scanning refers to the print head 3 moving relatively to the target object W1 while ejecting ink.

[0016] The print head 3 is attached to the tip surface of the arm 226. The tip surface of the arm 226 is the surface to which various end effectors can be attached, and in this embodiment, the print head 3 corresponds to the end effector. The print head 3 may be attached directly to the tip surface of the arm 226, or may be attached via a jig such as an attachment or a moving stage.

[0017] Furthermore, the position at which the print head 3 is attached is not limited to the center position of the tip surface of the arm 226. Furthermore, when viewed in plan from the direction along the Z axis, part of the print head 3 may protrude from the tip surface of the arm 226. Furthermore, when the print head 3 is attached to the arm 226 via a jig, the entire print head 3 may protrude from the tip surface of the arm 226.

[0018] As shown in FIG. 2, the print head 3 has a plurality of nozzles 31 that open in the -Z direction. The plurality of nozzles 31 eject ink onto the printing surface of the target object W1. The plurality of nozzles 31 are arranged at equal intervals along the X axis to form nozzle rows 311 and 312. The nozzle row 311 and the nozzle row 312 are arranged side by side in two rows in the Y axis direction. Therefore, when viewed from the Z direction, the region in which the plurality of nozzles 31 are arranged extends along the X axis direction. Note that, hereinafter, for simplicity of explanation, the print head 3 will be referred to as extending along the X axis direction. Note that the number of nozzle rows is not particularly limited.

[0019] In this embodiment, the print head 3 extends along a first direction, which corresponds to the -X direction. The end of the print head 3 on the -X direction side corresponds to the first end, and the end on the +X direction side, which is the opposite direction to the -X direction, corresponds to the second end.

[0020] Printing is performed by scanning the print head 3 with the robot arm 22, and the scanning print head 3 ejects ink onto the target object W1. The scanning direction of the print head 3 is the Y-axis direction, and the print head 3 moves along the printing surface of the target object W1. In other words, the extension direction and scanning direction of the print head 3 are perpendicular to each other.

[0021] 3, the control device 4 has a robot control unit 41, a print head control unit 42, and a storage unit 43. The control device 4 also corresponds to a control unit.

[0022] The robot control unit 41 controls the operation of the robot 2 based on a program stored in the storage unit 43. More specifically, it controls the control point of the robot arm 22 to pass through a path CP (see FIG. 8) generated by a teaching operation described later. The control point is a point that serves as a reference when the robot 2 operates, and is set as a coordinate on a spatial coordinate axis.

[0023] The print head control unit 42 controls the ejection of ink from the print head 3 based on the program stored in the memory unit 43 and data on the pattern to be printed. More specifically, it controls the ejection of ink in accordance with the movement of the robot 2. Note that in this embodiment, the pattern is a design desired by the worker and is not particularly limited, and may be, for example, letters, numbers, symbols, figures, images, or combinations of these, or a single color.

[0024] The robot control unit 41 and the print head control unit 42 may be provided in a single housing, or may be provided in separate housings.

[0025] The teaching device 5 generates a path CP along which the control points of the robot arm 22 pass, while changing the position and posture of the robot arm 22 through teaching operations performed by an operator. Information about the generated path CP is transmitted to the storage unit 43.

[0026] The control device 4 and the teaching device 5 may be separate or integrated. When they are separate, the teaching device 5 may have some of the above-described functions of the control device 4.

[0027] 1.2.Printing method The following describes each step of the printing method according to the first embodiment. Note that the following description will be given by way of an example in which printing is performed on an object W1 having a flat printing surface by scanning the print head 3 twice using the printing system 1 described above.

[0028] Fig. 4 is a flowchart for explaining the printing method according to the first embodiment. The printing method shown in Fig. 4 includes a first tool point setting step S101, a second tool point setting step S102, a printing path teaching step S103, a step S104 of setting control points to the first tool points, a first printing step S105, a step S106 of setting control points to the second tool points, and a second printing step S107.

[0029] In the first tool point setting step S101, the position of the first tool point TP1 is set in preparation for the first printing step S105. The tool point is a point set at the tip of the tool used by the robot to work, and serves as the reference point for the tool. The tool point is set as a position in the tool coordinate system described above. The tool is a general term for a hand attached to the wrist of a robot, a welding torch, a spot gun, etc., and is also called an end effector. In this embodiment, the print head 3 corresponds to the tool, and the tool point is set at the tip of the print head 3 in the -Z direction.

[0030] 5, the first tool point TP1 is set at the first end of the print head 3, i.e., the end on the -X direction side. More specifically, as shown in FIG. 2, the first tool point TP1 is set at an intermediate position between the nozzle 31 located at the end of the nozzle row 311 in the -X direction and the nozzle 31 located at the end of the nozzle row 312 in the -X direction.

[0031] Specifically, the operator inputs the spatial coordinates of the first tool point TP1 from an input device (not shown). The input spatial coordinates are stored in the storage unit 43. The method of setting the first tool point TP1 is not limited to this, and for example, spatial coordinates registered in advance in the storage unit 43 may be selected.

[0032] In the second tool point setting step S102, the position of the second tool point TP2 is set in preparation for the second printing step S107. As shown in FIG. 6, the second tool point TP2 is set at the second end of the print head 3, i.e., the end on the +X direction side. More specifically, as shown in FIG. 2, the second tool point TP2 is set at an intermediate position between the nozzle 31 located at the end of the nozzle row 311 in the +X direction and the nozzle 31 located at the end of the nozzle row 312 in the +X direction. The method for setting the second tool point TP2 is the same as in the first tool point setting step S101 described above, and therefore a description thereof will be omitted.

[0033] In the printing path teaching step S103, a path CP is generated. The path CP is a path along which the control point of the robot arm 22 passes in the first printing step S105 and the second printing step S107, which will be described later.

[0034] First, the position of control point TP0 is set as the control point to be used for teaching. As shown in FIG. 2, the position of control point TP0 is set at the tip of print head 3 in the -Z direction and the center in the X-axis direction. In other words, the position at which control point TP0 is set is midway between first tool point TP1 and second tool point TP2. The method for setting control point TP0 is the same as the first tool point setting step S101 described above, and so a description thereof will be omitted.

[0035] Next, the worker prepares the print head 3 attached to the tip of the arm 226 and the target object W1 in a fixed state. Then, the worker operates the teaching device 5 to move the robot arm 22 and generate a path CP along which the control point TP0 passes.

[0036] In this embodiment, a first print pattern p1 is printed in the first printing step S105, and a second print pattern p2 is printed in the second printing step S107. These two print patterns p1 and p2 are printed so that they are adjacent in a direction perpendicular to the scanning direction. Therefore, in the printing path teaching step S103, a path CP is generated so that a control point passes through the boundary where the two print patterns p1 and p2 are adjacent to each other. As described above, the scanning direction of the print head 3 is the Y-axis direction, and in this embodiment, the path CP is a path that progresses linearly in the +Y direction.

[0037] The path CP may be generated by a jig attached to the arm 226 instead of the print head 3. If a needle-like protrusion is provided at the tip of the jig and a control point TP0 is set at the tip position of this protrusion, visibility for the operator is improved, making it easier to align the path CP.

[0038] The target object W1 does not have to be the actual object to be printed, but may be a dummy object of the same shape. In this case, a test print can be performed to check the route CP.

[0039] A line indicating the path CP may be drawn on the printing surface of the target object W1. The operator can visually recognize this line and the position of the print head 3, making it easier to create the path CP.

[0040] The worker may also generate the route CP offline using 3D-CAD data of the target object W1. This allows the worker to generate the route CP without using the actual machine, thereby improving work efficiency. The worker may also generate a tentative route CP offline and then modify it using the actual machine to generate the route CP. This allows the generation of a highly accurate route CP.

[0041] The route CP thus generated is stored in the storage unit 43.

[0042] The order in which the first tool point setting step S101, the second tool point setting step S102, and the print path teaching step S103 are performed is not limited. For example, the first tool point setting step S101 and the second tool point setting step S102 may be performed after the print path teaching step S103 is performed.

[0043] In step S104 of setting the control point to the first tool point, the coordinates of the first tool point TP1 are set as the control point of the robot arm 22. In this embodiment, as shown in FIG. 7, this setting is performed using command Cd1 written into the program executed in the first printing step S105. The numbers in parentheses in command Cd1 represent the position information of the first tool point TP1, and from left to right, the coordinates on the X, Y, and Z axes, as well as the angles around the Z, Y, and X axes, are set. This sets the first tool point TP1 set at the first end to pass through the path CP pre-stored in step S103 of teaching the printing path. The control point set here is the control point used in the first printing step S105, which will be described later, and therefore corresponds to the first control point.

[0044] Even if position information is not written in the command, as in command Cd1, it is possible to have a table stored in memory unit 43 called up by executing the program. The table can store information for multiple print heads 3 with different shapes, so even when the print head 3 is replaced, the burden on the worker of rewriting the program can be reduced.

[0045] In the first printing step S105, the printing system 1 performs the first printing, i.e., the first printing, according to the program. Specifically, when the program is executed, the robot arm 22 moves the first control point along the path CP. This movement of the robot arm 22 causes the print head 3 to scan. Because the first tool point TP1 is set as the first control point, as shown in FIG. 8, the first end of the print head 3 moves in the +Y direction along the path CP, and the center of the print head 3 in the extension direction passes through the path r11. In this way, the first print pattern p1 is printed on the +X side of the path CP.

[0046] Next, in step S106 of setting a control point to a second tool point, the control point of the robot arm 22 is set to the coordinates of the second tool point TP2. In this embodiment, as shown in FIG. 7, this setting is performed using command Cd2 written into the program executed in the second printing step S107. Similar to command Cd1, the number in parentheses in command Cd2 is the position information of the second tool point TP2. This sets the second tool point TP2, which is set at the second end, to pass through the path CP pre-stored in the printing path teaching step S103. The control point set here is the control point used in the second printing step S107, which will be described later, and therefore corresponds to the second control point. Other aspects are the same as in step S104 of setting a control point to a first tool point, so further description will be omitted.

[0047] In the second printing step S107, the printing system 1 performs a second printing, i.e., a second print, according to the program. Specifically, when the program is executed, the robot arm 22 moves the second control point along the path CP. This movement of the robot arm 22 causes the print head 3 to scan. Because the second tool point TP2 is set as the second control point, as shown in FIG. 8, the second end of the print head 3 moves in the +Y direction along the path CP, and the center of the print head 3 in the extension direction passes through the path r12. In this way, a second print pattern p2 aligned with the first print pattern p1 is printed on the -X side of the path CP.

[0048] In addition, the movement speed of the first control point when it is moved along the path CP in the first printing process S105 and the movement speed of the second control point when it is moved along the path CP in the second printing process S107 are both constant and equal to each other.

[0049] Furthermore, in the first printing step S105 and the second printing step S107, the time intervals at which the print head 3 ejects ink during scanning are constant and the same for both steps.

[0050] By performing the above steps, the first print pattern p1 and the second print pattern p2 are printed side by side. In other words, the two print patterns p1 and p2 are side by side. The print head 3 scans two paths, path r11 and path r12, but the first control point in the first printing step S105 and the second control point in the second printing step S107 pass through the same path CP. In other words, only one path CP needs to be generated in advance during teaching, which reduces the burden on the operator during teaching work.

[0051] The direction in which the print head 3 scans, i.e., the direction of the path CP, and the direction in which the print head 3 extends, i.e., the first direction, are perpendicular to each other. This makes the width of the print head 3 maximum when viewed from the direction of the path CP, allowing printing to be performed over a wide area.

[0052] Furthermore, the extension direction of the print head 3 is along the X-axis, and a first control point is set at a first end in the direction in which the print head 3 extends, and a second control point is set at a second end in the opposite direction to the extension direction. This allows the first print pattern p1 and the second print pattern p2 to be printed adjacent to each other. In other words, the overlap width and separation distance between the two print patterns p1 and p2 printed side by side can be reduced. This allows for highly accurate and aesthetically pleasing printing.

[0053] 2, in a plan view from the direction in which the arm 226 and print head 3 are aligned, the first tool point TP1, which is the first control point, and the second tool point TP2, which is the second control point, overlap on the tip surface of the arm 226 to which the print head 3 is attached. In other words, the first control point and the second control point are close to the center of the tip surface of the arm 226. This prevents minute vibrations caused by the operation of the robot arm 22 from being amplified and transmitted to the print head 3. In this way, the effect on the positional accuracy of the print head 3 can be reduced, enabling accurate printing in the first printing process S105 and the second printing process S107.

[0054] Furthermore, in this embodiment, an example has been described in which a first control point is set at one end of the direction in which the print head 3 extends, and a second control point is set at the other end, but this is not limiting, and for example, the first control point and the second control point may be positioned differently in the direction in which the print head 3 extends. This makes it possible to change the relative positions of the first print pattern p1 and second print pattern p2 to be printed.

[0055] For example, suppose the first tool point TP1 is set to a position 5 mm on the +X side from the position shown in FIG. 5. That is, this position is shifted 5 mm toward the center in the direction in which the print head 3 extends from the first end of this embodiment. In this case, the operator sets the second tool point TP2 to a position 5 mm on the +X side from the position shown in FIG. 6. In this way, as in the above-described embodiment, the first print pattern p1 and the second print pattern p2 can be printed adjacent to each other. In other words, the position of the second tool point TP2 needs only to be shifted in the same direction and by the same distance as the first tool point TP1.

[0056] By applying this, the operator can adjust the overlap width or separation distance of two print patterns p1 and p2 printed side by side by changing the shift distance. In other words, by setting the first control point and the second control point at different positions in the first direction, the two print patterns can be printed side by side.

[0057] Furthermore, in this embodiment, the direction in which the print head 3 extends is described as being along the X-axis, but this is not limited thereto and the print head 3 may be inclined relative to the X-axis. In other words, the first direction may be inclined relative to the path CP. This reduces the width of the print head 3 when viewed from the direction of the path CP, making it possible to avoid the print head 3 colliding with an obstacle or the like. In this way, the path CP and the first direction may be orthogonal or inclined, as long as the path CP and the first direction intersect.

[0058] In this embodiment, the printing surface is described as a flat surface, but this is not limited to this and may be the side surface or inner surface of a cylinder. In this case, the path CP may be set in a direction perpendicular to the central axis of the cylinder or column.

[0059] The shape of the target object may also be, for example, a sphere. That is, the surface to be printed may be a sphere. In this case, the path CP may be set on the great circle of the sphere. Note that the great circle is the circle with the largest circumference.

[0060] The printing method according to the first embodiment has been described above. As previously mentioned, this printing method prints multiple print patterns p1 and p2 aligned with each other while changing the position of the print head 3 relative to the target object W1 by controlling the control point of the robot 2 along a pre-stored path. The printing method includes a first printing step S105 in which a first control point is moved along the path CP to print a first print pattern p1, and a second printing step S107 in which a second control point, different from the first control point in a first direction in which its position relative to the print head 3 intersects with the path CP, is moved along the path CP to print a second print pattern p2 aligned with the first print pattern. As a result, the first control point in the first printing step S105 and the second control point in the second printing step S107 follow the same path CP, so that advance teaching of a single path CP is sufficient. This reduces the amount of teaching work required and the burden on the operator.

[0061] As described above, the printing system 1 according to the first embodiment includes a print head 3, a robot 2 that changes the relative position of the print head 3 and the target object W1, and a control device 4 that controls the operation of the print head 3 and the robot 2. The control device 4 performs a first printing operation to print a first print pattern p1 by moving a first control point along a path CP stored in advance by the robot 2. The control device 4 then performs a second printing operation to print a second print pattern p2 aligned with the first print pattern p1 by moving a second control point, which is different from the first control point in a first direction and whose position relative to the print head 3 intersects with the path CP, along the path CP by the robot 2. As a result, the first control point in the first printing process S105 and the second control point in the second printing process S107 follow the same path CP, so that advance teaching of a single path CP is sufficient. This reduces the amount of teaching work required and the burden on the operator.

[0062] 2. Second embodiment A printing method according to the second embodiment will be described. As this embodiment, an example will be described in which the printing system 1 described above is used to print on an object W1 having a flat printing surface by scanning the print head 3 three times, as shown in FIG. 9. The following explanation will focus on differences from the first embodiment described above, and a description of similar matters will be omitted. Note that in the drawings of this embodiment, the same reference numerals are used to designate components similar to those in the previously described embodiment.

[0063] First, we will explain how to set the tool points, which serve as reference points for scanning the print head 3. This explanation corresponds to the first tool point setting step S101 and the second tool point setting step S102 in the first embodiment. In this embodiment, printing is performed three times, so three tool points are set: a third tool point TP3, a fourth tool point TP4, and a fifth tool point TP5.

[0064] 10, the third tool point TP3 is set at a position shifted in the -X direction from the first end of the print head 3. The shifted distance is half the distance from the first end to the second end.

[0065] As shown in FIG. 11, the fourth tool point TP4 is set at the center position of the width of the print head 3 in the X direction.

[0066] 12, the fifth tool point TP5 is set at a position shifted in the +X direction from the second end of the print head 3. The shifted distance is half the distance from the first end to the second end.

[0067] Next, the path CP will be described with reference to Fig. 9. This description corresponds to the printing path teaching step S103 in the first embodiment.

[0068] In the printing process described below, the print head 3 scans three times in the Y-axis direction, printing the third print pattern p3, the fourth print pattern p4, and the fifth print pattern p5 side by side in that order in the X-axis direction. Therefore, the path CP is a path that progresses linearly in the +Y direction from the center position in the X-axis direction of the fourth print pattern p4.

[0069] Next, the setting of the control points of the robot arm 22 and the printing process will be described with reference to Fig. 9. This description corresponds to the step S104 of setting the control points to the first tool points, the first printing step S105, the step S106 of setting the control points to the second tool points, and the second printing step S107 in the first embodiment.

[0070] In preparation for the first printing, the control point of the robot arm 22 is set to the coordinates of the third tool point TP3. The control point set here is called the first control point because it is the control point used in the first printing process.

[0071] In the first printing process, the robot arm 22 moves the first control point along the path CP. The operation of the robot arm 22 causes the print head 3 to scan. Because the third tool point TP3 is set as the first control point, as shown in FIG. 9, the print head 3 moves in the +Y direction while remaining spaced apart from the path CP in the +X direction. The center of the extension direction of the print head 3 passes through the path r21. In this way, the third print pattern p3 is printed at a position away from the path CP on the +X side.

[0072] In preparation for the second printing, the control point of the robot arm 22 is set to the coordinates of the fourth tool point TP4. The control point set here is called the second control point because it is the control point used in the second printing process.

[0073] In the second printing process, the robot arm 22 moves the second control point along the path CP. The operation of the robot arm 22 causes the print head 3 to scan. Because the fourth tool point TP4 is set as the second control point, the center of the print head 3 in the extension direction moves in the +Y direction along the path CP, as shown in FIG. 9. In other words, the path r22 through which the center of the print head 3 in the extension direction passes coincides with the path CP. In this way, the fourth print pattern p4 is printed, aligned in the -X direction with respect to the third print pattern p3.

[0074] In preparation for the third printing, the control point of the robot arm 22 is set to the coordinates of the fifth tool point TP5. The control point set here is called the third control point because it is the control point used in the third printing process. The third control point is a control point different from the first and second control points.

[0075] In the third printing process, the robot arm 22 moves the third control point along the path CP. The third printing process corresponds to the third printing process. The operation of the robot arm 22 causes the print head 3 to scan. Because the fifth tool point TP5 is set as the third control point, as shown in FIG. 9, the print head 3 moves in the +Y direction while remaining spaced apart from the path CP in the -X direction. The center of the print head 3 in the extension direction passes through the path r23. In this way, the fifth print pattern p5 is printed at a position away from the path CP on the -X side. The fifth print pattern p5 is aligned in the -X direction with respect to the fourth print pattern p4.

[0076] The printing method according to the second embodiment has been described above. With this printing method, the first control point, the second control point, and the third control point are set at different positions in the first direction, even though the control points follow a single path CP. This allows the three print patterns p3, p4, and p5 to be printed side by side. That is, the third print pattern p3 and the fourth print pattern p4 are side by side, the fourth print pattern p4 and the fifth print pattern p5 are side by side, and the three print patterns p3, p4, and p5 are side by side. This means that printing can be performed over a wider area without increasing the burden on the operator performing the teaching work. Note that the three print patterns in this embodiment have been described as the third print pattern p3, the fourth print pattern p4, and the fifth print pattern p5, but these are examples of the first print pattern, the second print pattern, and the third print pattern, respectively.

[0077] As described above, the fourth tool point TP4 is set at the center position of the width in the X direction of the print head 3. The third tool point TP3 is set at a position shifted in the -X direction from the first end of the print head 3, and the fifth tool point TP5 is set at a position shifted in the +X direction from the second end of the print head 3, with the shifted distances here being half the distance from the first end to the second end. In this way, the three print patterns p3, p4, and p5 can be printed adjacent to each other.

[0078] Although an example in which the number of scans is three has been described, this embodiment can also make the number of scans four or more by appropriately adjusting the position of the tool point.

[0079] 3. Third embodiment A printing method according to the third embodiment will be described. In this embodiment, an example will be described in which the printing system 1 described above is used to perform two scans of the print head 3 to print on an object W2 whose printing surface is the side surface of a cone. The following description will focus on differences from the first embodiment described above, and a description of similar points will be omitted. Note that in the drawings of this embodiment, the same reference numerals are used to designate components similar to those in the previously described embodiment.

[0080] As shown in Figure 13, the target object W2 is conical, and the surface to be printed is its side. The direction in which the print head 3 scans is around the central axis Ar of the cone. The two print patterns p6 and p7 (see Figure 14) are printed so that they are adjacent in the direction in which the generatrix of the cone extends.

[0081] Each step will now be described using Figure 4. As with the first embodiment, the printing method according to this embodiment includes a first tool point setting step S101, a second tool point setting step S102, a printing path teaching step S103, a control point setting step S104 for the first tool point, a first printing step S105, a control point setting step S106 for the second tool point, and a second printing step S107.

[0082] The first tool point setting step S101 and the second tool point setting step S102 are the same as those in the first embodiment, and therefore the description thereof will be omitted.

[0083] The printing path teaching step S103 will now be described. First, as in the first embodiment, the position of the control point TP0 is set at the center in the X-axis direction at the tip of the print head 3 in the -Z direction, as shown in FIG.

[0084] Next, the worker generates a path CP. In this embodiment, as described below, a sixth print pattern p6 is printed in the first printing process S105, and a seventh print pattern p7 is printed in the second printing process S107. These two print patterns p6 and p7 are printed so that they are adjacent in the direction in which the generatrix extends, as described above. Therefore, in the printing path teaching process S103, a path CP is generated so that a control point passes through the boundary where these two print patterns p6 and p7 are adjacent. The direction of the path CP is the direction around the central axis Ar of the cone, and in this embodiment, it is the counterclockwise direction when viewed from the +X side, that is, the apex side of the cone.

[0085] In this embodiment, the orientation of the print head 3 when printing in the first printing step S105 and second printing step S107, which will be described later, is also taught. This orientation includes maintaining the distance between the print head 3 and the surface to be printed, i.e., moving the print head 3 relative to the surface to be printed along the surface. This orientation also includes the direction in which ink is ejected being perpendicular to the surface to be printed. This orientation also includes the direction in which the print head 3 extends being along the generatrix of the cone.

[0086] Step S104 of setting the control point as the first tool point is the same as in the first embodiment, and therefore a description thereof will be omitted.

[0087] 14 is a diagram showing the printing surface of object W2 laid out on a plane. For convenience, the scanning direction of print head 3 is defined as the Y-axis direction, and the extending direction of print head 3 is defined as the X-axis direction. The direction of the apex of the cone is defined as the +X-direction.

[0088] In the first printing step S105, the printing system 1 performs the first printing in accordance with the program. Specifically, when the program is executed, the robot arm 22 operates so that the first control point follows the path CP. The operation of the robot arm 22 causes the print head 3 to scan. Because the first tool point TP1 is set as the first control point, as shown in FIG. 14, the first end of the print head 3 moves in the +Y direction along the path CP, and the center of the print head 3 in the extension direction passes through the path r31. In this way, the sixth print pattern p6 is printed on the +X side of the path CP.

[0089] If the movement distance of the first end relative to the target object W2 is d2 and the movement distance of the second end is d1, when the sixth print pattern p6 is viewed in a plane, the movement distance d2 is greater than the movement distance d1. This is because the first end and second end move in an arc-shaped path centered on the +X side as the print head 3 scans while maintaining the aforementioned posture.

[0090] Step S106 of setting the control points as second tool points is the same as in the first embodiment, and therefore a description thereof will be omitted.

[0091] In the second printing step S107, the printing system 1 performs a second printing in accordance with the program. Specifically, when the program is executed, the robot arm 22 operates so that the second control point follows the path CP. The operation of the robot arm 22 causes the print head 3 to scan. Because the second tool point TP2 is set as the second control point, as shown in FIG. 14, the second end of the print head 3 moves in the +Y direction along the path CP, and the center of the print head 3 in the extension direction passes through the path r32. In this way, the seventh print pattern p7 is printed on the -X side of the path CP.

[0092] 14, when the seventh print pattern p7 is viewed in a plane, the movement distance of the first end relative to the target W2 is d4, and the movement distance of the second end is d3. This is for the same reason as the sixth print pattern p6.

[0093] By performing the above steps, the sixth print pattern p6 and the seventh print pattern p7 are printed adjacent to each other, even if the target object W2 is conical. The print head 3 scans two paths, path r31 and path r32, but the first control point in the first printing step S105 and the second control point in the second printing step S107 pass through the same path CP. This means that only one path CP needs to be generated in advance, reducing the burden on the operator during the teaching process. Furthermore, because the sixth print pattern p6 and the seventh print pattern p7 are printed adjacent to each other, the travel distance d3 relative to the second end of the target object W2 in the second printing step S107 is equal to the travel distance d2 relative to the first end of the target object W2 in the first printing step S105. This also reduces the misalignment between the print start and end positions of the two adjacent print patterns p6 and p7.

[0094] Furthermore, in this embodiment, the case where the surface to be printed is the side surface of a cone has been described, but this is not limited thereto. The surface to be printed may be flat and the path CP may be curved, i.e., the path along which the print head 3 moves relative to the target object W1 may be curved. In other words, the first end and the second end may move along an arc-shaped path. For example, this may be the case when printing a label on a DVD disc and the print head 3 scans around the central axis of rotation of the DVD disc.

[0095] The speed at which the first control point moves along the path CP and the speed at which the second control point moves along the path CP are equal to each other. This eliminates the need to adjust the time intervals at which ink is ejected. This allows desired printing to be performed without adding unnecessary settings, reducing the burden on the operator.

[0096] In this embodiment, the term "cone" includes not only a right circular cone but also an oblique circular cone and a truncated circular cone. The surface to be printed may be the entire side surface of the cone or a part of it.

[0097] In this embodiment, an example has been described in which two print patterns p6 and p7 are printed side by side, but it is possible to print three print patterns side by side by setting the tool points TP3, TP4, and TP5 in the second embodiment described above. Also, by appropriately adjusting the positions of the tool points, it is possible to increase the number of scans to four or more times.

[0098] 4. Fourth embodiment A printing system 10 according to a fourth embodiment will be described. The following description will focus on differences from the first embodiment, and a description of similar matters will be omitted. Note that in the drawings of this embodiment, the same reference numerals are used to designate the same components as those in the previously described embodiment.

[0099] 15 is an overall view showing the overall configuration of a printing system 10 according to a fourth embodiment. The printing system 10 includes a robot 2, a print head 3, a control device 4, and a teaching device 5. In the printing system 10, the print head 3 is located at a position distant from the robot 2, and the robot 2 performs printing while moving the target object W1.

[0100] The robot 2 has an arm 226 that is a distal end arm, and a hand 11 provided on the distal end surface of the arm 226. The hand 11 grasps an object W1. The hand 11 may be attached directly to the arm 226, or may be attached via a jig such as an attachment or a moving stage. The hand 11 may grasp the object W1 directly, or may grasp a jig attached to the object W1.

[0101] The print head 3 is fixed to a print head support base 12 installed on the floor or the like. The direction in which the print head 3 ejects ink is not particularly limited and may be, for example, vertically downward or horizontally. The print head 3 may be attached directly to the print head support base 12, or may be attached via a movable stage. The print head support base 12 may have a mechanism that can change the orientation of the print head 3, such as a goniostage or tilt stage.

[0102] This configuration reduces the amount of movement of the print head 3 during printing, making it easier to route and position the tubes (not shown) that connect the ink storage unit (not shown) and the print head 3 around the robot 2. This reduces the burden on the worker before printing begins. Also, vibrations generated by the robot 2 are less likely to be transmitted to the print head 3, allowing for more accurate or aesthetically pleasing printing.

[0103] 5. Specific examples of the subject matter An example of the target object in the embodiment of the present application is the exterior of a robot arm of a SCARA robot 100 shown in Fig. 16. An example will be described in which a print pattern p is printed on a print target surface 120 of the exterior.

[0104] Figure 16 shows arm 110, one of the multiple arms of SCARA robot 100. In Figure 16, the Za axis is an axis parallel to the rotation axis J of arm 110. The printing target surface 120 is part of the exterior of arm 110, and includes part of the side of a cone with its apex at the top of the drawing. The width of printing pattern p printed on printing target surface 120 in the Za axis direction is greater than its width in the direction in which print head 3 extends.

[0105] The printing system 1, 10 or printing method according to the present embodiment can print a print pattern p on the print target surface 120 on the exterior of the arm 110. The print pattern p is printed by two scans with the direction in which the print head 3 extends aligned with the Za axis direction. The two print patterns printed by the two scans are adjacent to each other in the Za axis direction and form the print pattern p.

[0106] As described above, since the print pattern p needs to be printed by performing two or more scans, the SCARA robot 100 is suitable as the target object in the present embodiment. Furthermore, since the print target surface 120 includes part of the side surface of a cone as described above, the SCARA robot 100 is even more suitable as the target object W2 in the third embodiment.

[0107] The print pattern p printed in this manner can be used as a substitute for a sticker. Conventionally, robots shipped from manufacturers often have stickers affixed to them, such as warnings for users or stickers indicating the robot's specifications. The work of affixing these stickers is often performed manually, and automation has not progressed. However, by utilizing the present embodiment, this affixing work can be eliminated, making it possible to reduce the manufacturing cost of the SCARA robot 100.

[0108] Although a SCARA robot (horizontal articulated robot) has been described as a specific example of the target object, the present invention is not limited to this and may be applied to various robots, such as a vertical articulated robot, a parallel link robot, or a human collaborative robot.

[0109] While the printing method and printing system have been described above based on the illustrated embodiment, the present invention is not limited to this. For example, the printing method according to this embodiment may be obtained by adding any desired process to the embodiment. Furthermore, the printing system according to this embodiment may be obtained by replacing each part of the embodiment with any component having the same function, or by adding any component to the embodiment. [Explanation of symbols]

[0110] 1, 10...printing system, 2...robot, 3...print head, 4...control device, 5...teaching device, 11...hand, 12...print head support base, 21...base, 22...robot arm, 31...nozzle, 41...robot control unit, 42...print head control unit, 43...memory unit, 100...scalar robot, 110...arm, 120...printing surface, 221 to 226...arm, 311, 312...nozzle array, Ar...central axis, Cd1, Cd2...command, CP...path, d1 to d4...movement distance Separation, J... rotation axis, p, p1 to p7... printing pattern, r11 to r32... path of print head, S101... first tool point setting process, S102... second tool point setting process, S103... printing path teaching process, S104... process of setting control point to first tool point, S105... first printing process, S106... process of setting control point to second tool point, S107... second printing process, TP0... control point, TP1 to TP5... tool points, W1, W2... object.

Claims

1. A printing method for printing a plurality of print patterns that are arranged side by side while changing the position of a print head relative to an object by controlling a control point of a robot along a pre-stored path, comprising: a first printing step of printing a first print pattern by moving a first control point along the path; a second printing step of printing a second print pattern aligned with the first print pattern by moving a second control point, which is different from the first control point in a first direction in which its position relative to the print head intersects with the path, along the path.

2. The printing method according to claim 1 , wherein the first direction is a direction perpendicular to the path.

3. the print head extends along the first direction, the first control point is set to a first end portion on the first direction side, The printing method according to claim 1 , wherein the second control point is set at a second end on a side opposite to the first direction.

4. 3. The printing method according to claim 1, further comprising a third printing step of printing a third print pattern aligned with the second print pattern by moving a third control point, the third control point having a position relative to the print head different from the first control point and the second control point in the first direction, along the path.

5. 3. The printing method according to claim 1, wherein the print head is attached to a tip surface of an arm of the robot, and the first control point and the second control point overlap with the tip surface in a planar view from a direction in which the arm and the print head are aligned.

6. In the first printing step, a moving distance of the object is greater at the first end than at the second end, The printing method according to claim 3 , wherein a moving distance of the second end portion relative to the object in the second printing step is equal to a moving distance of the first end portion relative to the object in the first printing step.

7. a moving speed of the first control point when the first control point is moved along the path in the first printing step; The printing method according to claim 6 , wherein in the second printing step, the second control points are moved along the path at constant speeds equal to each other.

8. A print head; a robot that changes the relative position of the print head and an object; a control unit that controls the operation of the print head and the robot, The control unit performing a first printing in which a first print pattern is printed by an operation of moving a first control point along a path stored in advance by the robot; A printing system characterized by performing a second printing in which a second print pattern is printed so as to be aligned with the first print pattern by moving a second control point, which is different from the first control point in a first direction whose position relative to the print head intersects with the path, along the path by the robot.

9. The printing system according to claim 8 , wherein the robot changes the relative position by moving the object.

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