Printing method and robot system

Abstract

To provide a printing method and a robot system that, when printing a plurality of lines by using a robot, can suppress the occurrence of a printing failure in which blanks and / or overlap between the printed lines is conspicuous.SOLUTION: A printing method for printing a plurality of lines uses a robot which relatively moves an ink ejection head relative to an object along a printing direction, and a detection part for detecting a relative trajectory of the ink eject head relative to the object. The printing method includes: an overlap width setting step of acquiring, by the detection part, an undulation amount of the trajectory in a direction crossing the printing direction, and setting an overlap width of the trajectory in printing the plurality of lines on the basis of the acquired undulation amount; and a printing step for printing the plurality of lines on the object while relatively moving the ink ejection head, so as to generate overlap corresponding to the overlap width in printing the plurality of lines.SELECTED DRAWING: Figure 5

Description

[Technical field]

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

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

[0003] For example, Patent Document 1 discloses a system for printing on a three-dimensional object, the system including a joint arm robot, a print head, a piezoelectric actuator disposed between them, and a detector for detecting the position of the print point. The robot is configured to move the print head along the surface of the object. This allows printing in multiple passes including adjacent print tracks.

[0004] Patent Document 1 also discloses that a piezoelectric actuator moves the print head relative to the robot. Patent Document 1 also discloses that when using this system to perform multi-pass printing while moving the print head on two adjacent print tracks, the actual position of the print point on the first print track is grasped, the deviation between the target position and the actual position is calculated, and a compensation motion is performed on the second print track to eliminate the deviation. This reduces deviation between the print passes, making it possible to print an image without errors. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2013-202781 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, the system described in Patent Document 1 cannot fully eliminate the misalignment between the target position and the actual position due to factors such as vibrations generated in the robot. If the misalignment is not fully eliminated, printing defects such as blank spaces between printing passes or noticeable overlap between printing passes occur. [Means for solving the problem]

[0007] A printing method according to an application example of the present invention includes: A printing method for printing a plurality of lines using an ink ejection head that ejects ink, a robot that moves the ink ejection head relative to an object along a printing direction, and a detection unit that detects a relative trajectory of the ink ejection head with respect to the object, comprising: an overlap width setting step in which the detection unit acquires an amount of undulation of the locus in a direction perpendicular to the printing direction, and sets an overlap width of the locus when printing a plurality of lines based on the acquired amount of undulation; a printing step of printing a plurality of lines on an object while moving the ink ejection head relatively so that an overlap corresponding to the overlap width occurs in printing the plurality of lines; has.

[0008] A robot system according to an application example of the present invention includes: A robotic system for printing multiple lines on an object, comprising: an ink ejection head that ejects ink; a robot having a robot arm that moves the ink ejection head relative to an object in a printing direction; a detection unit that detects a relative trajectory of the ink ejection head with respect to an object; a print control unit that controls the operation of the ink ejection head and the robot; Equipped with The print control unit a swell amount acquisition unit that acquires a swell amount of the locus in a direction perpendicular to the printing direction; an overlap width setting unit that sets an overlap width between the tracks when printing a plurality of lines based on the acquired undulation amount; having The ink ejection head prints a plurality of lines on the target object while the robot moves the ink ejection head relatively so that an overlap corresponding to the overlap width occurs when printing the plurality of lines. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a perspective view showing the overall configuration of a robot system (printing device) according to a first embodiment. [Diagram 2] 2 is a functional block diagram of the printing device shown in FIG. 1. [Diagram 3] 2 is a plan view showing the moving stage and the liquid ejection head shown in FIG. [Figure 4] FIG. 2 is a schematic diagram illustrating an outline of a printing method according to the first embodiment. [Diagram 5] 4 is a flowchart illustrating a printing method according to the first embodiment. [Figure 6] FIG. 6 is a schematic diagram for explaining the printing method shown in FIG. 5. [Figure 7] FIG. 6 is a schematic diagram for explaining the printing method shown in FIG. 5. [Figure 8] FIG. 6 is a schematic diagram for explaining the printing method shown in FIG. 5. [Figure 9] 11 is a graph showing the relationship between the residual error in two directions D1 and D2 and the corresponding overlap width. [Figure 10] 13 is a schematic diagram for explaining a method of thinning out dots in a range OL corresponding to the overlap width. FIG. [Figure 11] 13 is a schematic diagram for explaining a method of thinning out dots in a range OL corresponding to the overlap width. FIG. [Figure 12] 10 is a flowchart illustrating a printing method according to a second embodiment. [Figure 13] 13 is a flowchart illustrating a printing method according to a third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

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

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

[0012] 1.1.Printing device Fig. 1 is a perspective view showing the overall configuration of a robot system (printing device 100) according to the first embodiment. Fig. 2 is a functional block diagram of the printing device 100 shown in Fig. 1. Fig. 3 is a plan view showing a moving stage 300 and a liquid ejection head (ink ejection head) 400 shown in Fig. 1.

[0013] The printing apparatus 100 shown in FIG. 1 includes a robot 200, a liquid ejection head 400, a fixing member 700 that supports and fixes a target object Q, a camera 800, and a control device 900.

[0014] The robot 200 is a six-axis vertical articulated robot having six drive axes. The robot 200 has a base 210 fixed to the floor, a robot arm 220 connected to the base 210, and a moving stage 300 attached to the robot arm 220. The number of drive axes of the robot 200 may be more or less than six. The robot 200 may also be a horizontal articulated robot, or a multi-arm robot having multiple robot arms.

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

[0016] A liquid ejection head 400 is attached to the tip of the arm 226 via a moving stage 300, as shown in Fig. 3. The liquid ejection head 400 shown in Fig. 3 has an ink chamber (not shown), a vibration plate arranged on the wall of the ink chamber, and ink ejection holes 411 connected to the ink chamber, and is configured so that ink in the ink chamber is ejected from the ink ejection holes 411 by vibration of the vibration plate. However, the configuration of the liquid ejection head 400 is not particularly limited.

[0017] The printing apparatus 100 also includes a print controller 420. The liquid ejection head 400 is connected to the print controller 420 as shown in Fig. 2. In the example of Fig. 1, the print controller 420 is attached to the tip of the arm 226 via the moving stage 300, similar to the liquid ejection head 400. The print controller 420 controls the operation of the liquid ejection head 400 based on a control signal output from the control device 900.

[0018] The print controller 420 includes, for example, a processor such as one or more CPUs (Central Processing Units), a memory, an external interface, etc. The print controller 420 may include a programmable logic device such as an FPGA (Field Programmable Gate Array) instead of or in addition to a CPU. The print controller 420 may be incorporated in the control device 900.

[0019] As shown in FIG. 3, the moving stage 300 has a base 310 connected to the arm 226, a stage 320 that moves relative to the base 310, and a moving mechanism 330 that moves the stage 320 relative to the base 310. As shown in FIG. 3, when three mutually orthogonal axes are defined as an X-axis, a Y-axis, and a Z-axis, the stage 320 has a Y-stage 320Y that can move in a direction along the Y-axis relative to the base 310, and an X-stage 320X that can move in a direction along the X-axis relative to the Y-stage 320Y. The X-stage 320X and the Y-stage 320Y are linearly guided in the X-axis and Y-axis directions by linear guides (not shown), and can move smoothly. The liquid ejection head 400 is attached to the X-stage 320X.

[0020] The movement mechanism 330 has a Y movement mechanism 330Y that moves the Y stage 320Y in a direction along the Y axis relative to the base 310, and an X movement mechanism 330X that moves the X stage 320X in a direction along the X axis relative to the Y stage 320Y.

[0021] The Y-moving mechanism 330Y and the X-moving mechanism 330X each have a piezoelectric actuator 340 as a driving source. The piezoelectric actuator 340 vibrates by utilizing the expansion and contraction of a piezoelectric element, and moves the X-stage 320X and the Y-stage 320Y by transmitting the vibration. This allows the moving stage 300 to be made smaller and lighter. In addition, the driving accuracy of the moving stage 300 is improved. Furthermore, the piezoelectric actuator 340 is useful in that it does not require an additional brake because of its large holding torque when stopped, and in that the positional stability of the stage 320 when stopped is high. Note that, as the driving source, a mechanism other than the piezoelectric actuator 340, for example, a mechanism combining a rack-and-pinion gear and a rotary motor, or a mechanism combining a ball screw and a rotary motor, may be used.

[0022] The printing apparatus 100 also includes a robot controller 240. The motor M and the encoder E are connected to the robot controller 240. The robot controller 240 controls the operation of the robot 200 based on a control signal output from the control device 900.

[0023] The robot controller 240 has, as its functional units, an arm control unit 242, a moving stage controller 244, and a memory unit 246.

[0024] The arm control unit 242 outputs a control signal that controls the operation of the arm drive mechanism 230, thereby controlling the robot arm 220 to a desired posture.

[0025] The moving stage controller 244 outputs a control signal that controls the operation of the moving stage 300, thereby moving the liquid ejection head 400 to a target position relative to the robot arm 220. Note that the moving stage controller 244 may be independent from the robot controller 240.

[0026] The memory unit 246 stores programs necessary for the operation of the robot controller 240, data necessary for executing the programs, and the like.

[0027] The robot controller 240 includes, for example, one or more processors such as CPUs, a memory, an external interface, etc. Note that the robot controller 240 may include a programmable logic device such as an FPGA instead of or in addition to a CPU.

[0028] The camera 800 is disposed on the arm 225 while facing the tip side of the robot arm 220. By disposing the camera 800 on the robot arm 220 in this manner, it is possible to capture an image of the object Q from a relatively close distance, and a clearer image can be obtained.

[0029] The location of the camera 800 is not particularly limited, and may be, for example, on the arms 221 to 224 and 226, or may be located at a position away from the robot 200. Examples of the camera 800 include a monochrome camera, a color camera, and a spectroscopic camera.

[0030] The control device 900 controls the operations of the robot controller 240, the print controller 420, and the camera 800 to execute printing on the target object Q. The control device 900 has, as functional units, a print control unit 910 and a storage unit 930. The print control unit 910 includes a print data generation unit 912, a swell amount acquisition unit 914, a front / rear amount acquisition unit 916, a correction amount setting unit 918, and an overlap width setting unit 920.

[0031] The print data generation unit 912 generates print data and outputs it to the robot controller 240 and the print controller 420 .

[0032] The swell amount acquiring unit 914 and the front-rear amount acquiring unit 916 acquire the “swell amount” and the “front-rear amount” described below. The swell amount and the front-rear amount are the deviation amounts from the scanning trajectory acquired for the trajectory of the liquid ejection head 400.

[0033] The correction amount setting unit 918 sets the amount (correction amount) by which the liquid ejection head 400 is moved relative to the scanning trajectory based on the amount of swell and the amount of front-back movement.

[0034] The overlap width setting unit 920 sets the overlap width between the trajectories of the liquid ejection head 400 when printing multiple lines, based on the amount of swell and the amount of front and rear movement. Then, the overlap width that has been set is output to the robot controller 240.

[0035] The storage unit 930 stores programs necessary for the operation of the control device 900, data necessary for executing the programs, and the like.

[0036] The control device 900 is, for example, configured as a computer, and has a processor (CPU) for processing information, a memory communicatively connected to the processor, and an external interface. In addition, various programs executable by the processor are stored in the memory, and the processor realizes the above-mentioned functions by reading and executing the various programs stored in the memory.

[0037] The configuration of the robot system (printing apparatus 100) according to the first embodiment has been described above, but the moving stage 300 may not be part of the robot 200, and may be disposed so as to support the target object Q at a position separated from the robot 200. In this case as well, the liquid ejection head 400 can be moved relatively to the target object Q by operating the moving stage 300 supporting the target object Q.

[0038] 1.2.Printing method Next, a description will be given of a printing method according to the first embodiment. In the following description, a method using the printing device 100 described above will be described as an example. The printing method according to the first embodiment is a printing method in which a plurality of lines are printed on an object Q.

[0039] Fig. 4 is a schematic diagram showing an outline of the printing method according to the first embodiment. Fig. 5 is a flowchart for explaining the printing method according to the first embodiment. Figs. 6 to 8 are schematic diagrams for explaining the printing method shown in Fig. 5.

[0040] As shown in FIG. 4, in the printing method according to the first embodiment, multiple lines including a first line L1 and a second line L2 adjacent to each other are printed. A line refers to a path (scanning line) through which the liquid ejection head 400 passes. That is, the first line L1 can be printed by scanning the liquid ejection head 400 in a printing direction D2 by the operation of the robot 200 while ejecting ink from the liquid ejection head 400. In addition, the liquid ejection head 400 is shifted in an orthogonal direction D1 perpendicular to the printing direction D2 by the operation of the robot arm 220. Then, the second line L2 is printed by scanning the liquid ejection head 400 in the printing direction D2 again.

[0041] As described above, in such a method, vibrations and the like generated in the robot arm 220 can cause the trajectory of the liquid ejection head 400 to shift, resulting in printing defects such as blank spaces between lines or noticeable overlap between lines.

[0042] Therefore, in the printing method according to the first embodiment, the deviation of the trajectory of the liquid ejection head 400 is detected, and the overlap width between the lines is set based on the detection result. The overlap width refers to the width in the orthogonal direction D1 of the range where the first line L1 and the second line L2 overlap. This makes it possible to optimize the overlap width, and even if a blank space occurs between the lines or a change in density occurs due to the overlap between the lines, it is possible to make it less noticeable. As a result, high-quality printing can be performed on the object Q.

[0043] The printing method according to the first embodiment includes an overlap width setting step S100 and a printing step S200, as shown in Fig. 5. Each step will be described below.

[0044] 1.2.1.Overlap width setting process The overlap width setting process S100 includes operations from step S102 to step S118.

[0045] In step S102, an object other than the object to be printed, that is, a temporary object, is prepared as the object Q. This is to avoid the object to be printed being soiled by printing the first pattern P1, which is a test pattern, as shown in FIG. 6. The temporary object may be another object having the same shape as the object to be printed, or may be an object having a coating layer formed on the surface of the object to be printed. Examples of materials constituting the coating layer include paper and resin. This coating layer may be removed after the overlap width setting step S100 is completed.

[0046] Then, in step S102, the print data generating unit 912 of the control device 900 generates print data corresponding to the first pattern P1. Then, the robot controller 240 creates a scanning trajectory T0 of the liquid ejection head 400 corresponding to the print data. Based on the created scanning trajectory T0, the liquid ejection head 400 prints the first pattern P1 in a range corresponding to the first row L1 of the target Q. Note that in this application, the printing in step S102 is also referred to as the "first printing". The first pattern P1 is a pattern in which dots d are arranged at equal intervals in the printing direction D2. Also, in step S102, the robot arm 220 operates so that the liquid ejection head 400 moves along the printing direction D2. Furthermore, in step S102, the moving stage 300 is not operated. In other words, the scanning trajectory T0 is a trajectory of the liquid ejection head 400 scanned only by the robot arm 220. Then, while the robot arm 220 moves the liquid ejection head 400 along the printing direction D2, the liquid ejection head 400 performs printing on the target Q. Such an operation of the robot 200 and the liquid ejection head 400 is referred to as a first pattern printing operation.

[0047] In step S104, the camera 800 detects the first pattern P1 obtained by the first pattern printing operation. Specifically, the camera 800 acquires an image of the first pattern P1. Then, the undulation amount acquisition unit 914 of the control device 900 calculates the position of the dot d from the image acquired by the camera 800. In this way, a relative trajectory T1 of the liquid ejection head 400 with respect to the target Q is detected. In other words, the position of the dot d is regarded as the trajectory T of the liquid ejection head 400. In this specification, the concept including the path of the liquid ejection head 400 created by the robot controller 240 and scanned by the robot 200 and the speed on that path is referred to as a "scanning trajectory". In addition, the concept including the path that the liquid ejection head 400 actually moved and the speed on that path is referred to as a "trajectory".

[0048] Then, in step S104, the waviness amount acquisition unit 914 of the control device 900 acquires at least the amount of deviation in a direction (orthogonal direction D1) perpendicular to the printing direction D2. The amount of deviation in the orthogonal direction D1 refers to the distance between the scanning track T0 and the dot d (trajectory T1) in the orthogonal direction D1 acquired for each dot d, as shown in FIG. 6. For convenience of explanation, in FIG. 6 and other figures of the present application, an upward deviation from the scanning track T0 is regarded as a positive deviation amount, and a downward deviation from the scanning track T0 is regarded as a negative deviation amount. Such an operation of the control device 900 is referred to as a first deviation amount acquisition operation. The amount of deviation acquired from the first pattern P1 is also referred to as an "initial deviation amount."

[0049] 6 includes a total of eight dots d, but the initial deviation in the orthogonal direction D1 and the initial deviation in the printing direction D2 are both 0 mm. In other words, the first pattern P1 shown in FIG 6 indicates that the trajectory T1 of the liquid ejection head 400 coincides with the scanning trajectory T0, which is an ideal state.

[0050] On the other hand, the first pattern P1 shown in FIG. 7 represents a non-ideal state. 7, three dots d are misaligned in the orthogonal direction D1, and five dots d are misaligned in the printing direction D2. Such deviations from the scanning trajectory T0 occur due to various reasons. Examples of such deviations include vibrations generated in the robot 200.

[0051] In this embodiment, the forward / backward amount acquisition unit 916 of the control device 900 also acquires an initial deviation amount in the printing direction D2. The initial deviation amount in the printing direction D2 refers to the distance between the ideal state in the printing direction D2 and the print result acquired for each dot d when the pattern in which dots d are printed at intervals of 1 mm is taken as the ideal state, as shown in FIG. 7. For convenience of explanation, in each figure of the present application, a deviation forward from the ideal state in the printing direction D2 is taken as a positive deviation amount, and a deviation backward is taken as a negative deviation amount. Also, the ideal state in the printing direction D2 in FIG. 6 to FIG. 8 refers to a state in which the dot d is arranged at the intersection of the scanning track T0 and a line perpendicular to it.

[0052] In step S106, the correction amount setting unit 918 of the control device 900 calculates the amount of movement (correction amount) of the liquid ejection head 400 in the direction to reduce the amount of deviation based on the initial deviation amount obtained by the first deviation amount acquisition operation. The correction amount is calculated based on the initial deviation amount. The calculation method may be a method based on an experiment or a simulation, and is not particularly limited. As an example, as shown in FIG. 7, a method of moving the liquid ejection head 400 in the opposite direction by the same amount of movement as the acquired initial deviation amount is exemplified. That is, all of the correction amounts shown in FIG. 7 are values ​​obtained by multiplying the acquired initial deviation amount by -1. The storage unit 930 of the control device 900 stores the correction amount for each scanning line in a state synchronized with the scanning of the liquid ejection head 400, that is, linked to the position of the liquid ejection head 400. Such an operation of the control device 900 is called a correction amount calculation operation.

[0053] This correction amount may be reflected in the scanning trajectory T0 in the printing process S200 described later, but is preferably reflected in the operation of the moving stage 300 in the printing process S200. In other words, this correction amount may be a control value for correcting the trajectory T1 by reflecting it in the operation of the robot arm 220, but is preferably used as a control value for correcting the trajectory T1 by reflecting it in the operation of the moving stage 300. This allows the trajectory T1 to be corrected more accurately, and ultimately, a good printing result can be obtained. In addition, since it is often difficult to suppress the influence of vibrations and the like in the robot arm 220 depending on the scanning speed, it is useful to perform correction using the moving stage 300.

[0054] In step S108, a temporary object different from the temporary object prepared in step S102 is prepared as the target object Q. Then, in step S108, the robot arm 220 and the moving stage 300 are used to print a second pattern P2 in an area corresponding to the first row L1 of the target object Q. In the present application, the printing in step S108 is also referred to as a "second printing". The second pattern P2 is a pattern in which dots d are arranged at equal intervals in the printing direction D2, and is the same pattern as the first pattern P1. In addition, in step S108, the robot 200 operates so that the liquid ejection head 400 moves along the printing direction D2. In addition, the scanning track T0 created by the robot controller 240 in the second printing is preferably the same as that in the first printing. Furthermore, in step S108, the moving stage 300 operates so that the liquid ejection head 400 moves along the orthogonal direction D1 and the printing direction D2.

[0055] In this embodiment, in step S108, the correction amount calculated in the correction amount calculation operation is reflected in the operation of the moving stage 300. As described above, this correction amount is set for the purpose of correcting deviation from the ideal state caused by causes such as vibrations occurring in the robot 200. In the second printing, the scanning trajectory T0 created by the robot controller 240 is preferably the same as that in the first printing. This increases the probability that deviation from the ideal state caused by the above causes will be the same in the second printing as in the first printing. As a result, if correction is performed using the correction amount calculated in the correction amount calculation operation, the probability that the deviation can be accurately corrected increases. Such an operation of the liquid ejection head 400 is called a second pattern printing operation.

[0056] In step S110, the camera 800 detects the second pattern P2 obtained by the second pattern printing operation. Specifically, the camera 800 acquires an image of the second pattern P2. The control device 900 then calculates the position of the dot d from the image acquired by the camera 800. As a result, the relative trajectory T2 of the liquid ejection head 400 with respect to the target Q is detected.

[0057] Then, in step S110, the waviness amount acquisition unit 914 of the control device 900 acquires the amount of misalignment at least in the orthogonal direction D1. In this embodiment, the amount of misalignment is acquired in both the orthogonal direction D1 and the printing direction D2. Such an operation of the control device 900 is referred to as a second misalignment amount acquisition operation. The amount of misalignment acquired from the second pattern P2 is also referred to as a "corrected misalignment amount." In this embodiment, the corrected misalignment amount in the orthogonal direction D1 is referred to as the "waviness amount," and the corrected misalignment amount in the printing direction D2 is referred to as the "front-rear amount."

[0058] In step S114, the absolute value of the waviness amount (corrected deviation amount in the orthogonal direction D1) is calculated for each dot d in the second pattern P2. Then, as shown in FIG. 8, the calculated absolute values ​​are added up for the entire second pattern P2. The obtained sum of the absolute values ​​is called the residual error in the orthogonal direction D1. Also, in step S114, the absolute value of the front / rear amount (corrected deviation amount in the printing direction D2) is calculated for each dot d in the second pattern P2. Then, as shown in FIG. 8, the calculated absolute values ​​are added up for the entire second pattern P2. The obtained sum of the absolute values ​​is called the residual error in the printing direction D2.

[0059] 8, in step S114, the residual error in the orthogonal direction D1 and the residual error in the print direction D2 are added together to calculate the residual error in the two directions D1 and D2. This residual error is the residual error of the first line L1.

[0060] Such an operation of the control device 900 is called a residual error calculation operation. Note that the calculation of the residual error may be performed as necessary, and may be omitted. In that case, the overlap width, which will be described later, may be set directly based on the amount of swell or the amount of front-rear movement, or a calculation different from the above may be performed on the amount of swell or the amount of front-rear movement, and the overlap width may be set based on the result of the calculation.

[0061] In step S116, the overlap width setting unit 920 of the control device 900 sets the overlap width based on the residual error in the two directions D1 and D2. This overlap width means the overlap width to be set when the second row L2 is overlapped with the first row L1 based on the residual error of the first row L1. Therefore, the storage unit 930 of the control device 900 stores this overlap width in a state linked to the first row L1. Such an operation of the control device 900 is called an overlap width setting operation.

[0062] The method of determining the overlap width based on the residual error in the two directions D1 and D2 is not particularly limited, but an example is a method using the correlation between the residual error in the two directions D1 and D2 and the overlap width shown in Fig. 9. Fig. 9 is a graph showing the relationship between the residual error in the two directions D1 and D2 and the corresponding overlap width. By using the relationship shown in Fig. 9, it is possible to derive an overlap width suitable for the residual error in the two directions D1 and D2. In the example of Fig. 9, it can be seen that if the residual error in the two directions D1 and D2 is 5 mm, the overlap width should be set to 6 mm.

[0063] The relationship shown in FIG. 9 is an upward sloping relationship such that the larger the residual error in the two directions D1 and D2, the wider the overlap width is set. This takes advantage of the phenomenon whereby by widening the overlap width in accordance with the residual error, printing defects become less noticeable even if a residual error is present. In other words, residual error is likely to cause abrupt changes in print density. However, by setting the overlap width wide, it is possible to mitigate the change in print density, making it less noticeable.

[0064] In step S118, the robot arm 220 performs a line feed on the scanning line of the liquid ejection head 400. That is, the liquid ejection head 400 is moved from the position of the first line L1 to the position of the second line L2 along the orthogonal direction D1. The line feed width at this time is usually set equal to the length of the liquid ejection head 400 in the orthogonal direction D1. On the other hand, if the overlap width set in the overlap width setting operation is greater than zero, the line feed width to be set is the normal line feed width minus the overlap width. For example, if the length of the liquid ejection head 400 in the orthogonal direction D1 is 24 mm and the overlap width is 6 mm, the line feed width to be set in step S118 is 18 mm. Such an operation of the robot arm 220 is called a line feed operation.

[0065] When only the initial deviation amount in the orthogonal direction D1 is obtained, step S114 may be omitted, and the overlap width may be calculated from only the residual error in the orthogonal direction D1 in step S116. In this case, the overlap width may be set based on a new graph in which the horizontal axis of the graph shown in FIG. 9 is the residual error in the orthogonal direction D1.

[0066] In step S120, it is determined whether or not it is necessary to set an overlap width for a new scan line. In other words, it is determined whether or not the overlap width settings have been completed up to the final scan line in the case of printing multiple lines. If the settings have not been completed, the process returns to step S102. If the settings have been completed, the process proceeds to the printing step S200.

[0067] When returning to step S102, in steps S102 to S118 for the second time, the residual error of the second line L2 is found, and the overlap width is set based on that. By repeating this operation up to the final scanning line, it is possible to set overlap widths for all scanning lines. Based on the overlap widths set in this manner, printing can be performed with an appropriate overlap width in the printing step S200, which will be described later.

[0068] 1.2.2.Printing process In the printing step S200, the liquid ejection head 400 prints multiple lines on the object Q while the robot arm 220 and the moving stage 300 relatively move the liquid ejection head 400 so that an overlap occurs according to the overlap width set in the overlap width setting step S100. That is, the control device 900 controls the operation of the robot 200 so that the scanning lines are overlapped based on the overlap width stored in association with each scanning line. In addition, the control device 900 controls the operation of the moving stage 300 so that the position of the liquid ejection head 400 is corrected for each scanning line based on the correction amount stored in association with the position of the liquid ejection head 400. This allows the scanning lines to be overlapped with an appropriate overlap width according to the residual error between each line. Therefore, high-quality printing can be performed without generating blank spaces between each line or noticeable changes in print density. In particular, this printing method is a method that can print even if the object Q is a three-dimensional object. When printing on a three-dimensional object, the posture of the robot arm 220 varies greatly depending on the position of the scanning line, and the vibration of the robot arm 220 also changes. Therefore, as in this embodiment, by experimentally finding an appropriate overlap width for each scanning line and printing multiple lines based on that, the effect on the printing result can be suppressed even if the vibration of the robot arm 220 changes.

[0069] In addition, in this embodiment, residual errors are reduced by the moving stage 300, and as a result, the overlap width can be reduced. Furthermore, the moving stage 300 can correct the position of the liquid ejection head 400 with higher accuracy and at higher speed than the robot arm 220. As a result, higher quality printing can be performed at higher speed.

[0070] When printing is performed in the printing step S200, the overlap width setting unit 920 may modify the print data in the range corresponding to the overlap width. This function is, for example, a function for modifying the print data so as to thin out dots in the range corresponding to the overlap width. This makes it possible to prevent the print density in the range corresponding to the overlap width from becoming excessively high.

[0071] 10 and 11 are schematic diagrams for explaining a method of thinning out dots in a range OL corresponding to the overlap width. In Fig. 10 and Fig. 11, an example is shown in which dots da constituting the scanning line LA and dots db constituting the scanning line LB are thinned out in a range OL where adjacent scanning lines LA and LB overlap each other.

[0072] In Fig. 10, the dots da and db are thinned out in a comb-like pattern in the range OL corresponding to the overlap width. In other words, in the range OL shown in Fig. 10, the comb-like set of dots da and the comb-like set of dots db are interdigitated. This prevents excessive increases in print density in the range OL.

[0073] Also, in FIG. 11, the dots da and db are thinned out based on the tone distribution in the range OL corresponding to the overlap width. The tone distribution is a process of dispersing dots so that they do not visually have a specific frequency. That is, in the range OL shown in FIG. 11, a set of dots da thinned out based on the tone distribution and a set of dots db thinned out based on the tone distribution are interlocked with each other. This prevents excessive increases in print density in the range OL. In addition, the tone distribution makes print defects caused by residual errors less noticeable than other thinning methods. Therefore, even if the residual errors cannot be sufficiently suppressed, print defects can be made less noticeable without securing an overlap width larger than necessary. As a result, high-quality printing can be performed without significantly reducing the print speed.

[0074] 2. Second embodiment Next, a printing method according to a second embodiment will be described. FIG. 12 is a flowchart illustrating a printing method according to the second embodiment.

[0075] The second embodiment will be described below, focusing on the differences from the first embodiment and omitting the description of the similarities. Note that in FIG. 12, the same reference numerals are used for the same configurations as the first embodiment.

[0076] The printing method according to the second embodiment is similar to the printing method according to the first embodiment, except that the method of calculating the "waviness amount" and "front-rear amount" for setting the overlap width is different.

[0077] In the first embodiment described above, in the overlap width setting step S100, the initial deviation amount and the corrected deviation amount are sequentially obtained, and then the corrected deviation amount is regarded as the "waviness amount" and the "front-rear amount." Then, the overlap width is set based on the residual error calculated from the waviness amount and the front-rear amount.

[0078] In contrast to this, in this embodiment, the initial deviation amount is regarded as the "waviness amount" and the "front-rear amount."

[0079] Specifically, in the printing method shown in FIG. 12, steps S108 and S110 relating to printing the second pattern P2 shown in FIG. 5 are omitted.

[0080] Meanwhile, in step S104, the initial deviation amount in the orthogonal direction D1 is set as the "waviness amount," and the initial deviation amount in the printing direction D2 is set as the "front-rear amount." Then, in step S114, the absolute value of this waviness amount and the absolute value of the front-rear amount are calculated, and are added together to calculate the residual error in the orthogonal direction D1 and the residual error in the printing direction D2. In the second embodiment as described above, the same effects as in the first embodiment can be obtained.

[0081] In addition, in the second embodiment, since printing and detection of the second pattern P2 can be omitted, the number of steps required to set the overlap width can be reduced, and the overlap width can be set in a shorter time.

[0082] 3. Third embodiment Next, a printing method according to a third embodiment will be described. FIG. 13 is a flowchart illustrating a printing method according to the third embodiment.

[0083] The third embodiment will be described below, focusing on the differences from the first embodiment and omitting the description of the similarities. In FIG. 13, the same reference numerals are used for the same configurations as the first embodiment.

[0084] The printing method according to the third embodiment is similar to the printing methods according to the first and second embodiments, except that the method of calculating the "waviness amount" and "front-rear amount" for setting the overlap width is different.

[0085] In the first and second embodiments described above, the dots d contained in each of the first pattern P1 and the second pattern P2 printed by the liquid ejection head 400 are detected, and the amount of waviness and the amount of front-rear movement are calculated based on the positions of the dots d.

[0086] In contrast to this, in this embodiment, the liquid ejection head 400 itself is detected by the camera 800, and the amount of swell and the amount of front-rear movement are obtained based on the position.

[0087] Specifically, the printing method shown in Fig. 13 omits steps S102, S104, S106, S108, and S110 shown in Fig. 5. On the other hand, the printing method shown in Fig. 13 includes steps S121, S122, and S124.

[0088] 13 is similar to step S102 in the first embodiment in that a pattern is printed, but is different from the first embodiment in that any pattern may be used. Note that step S121 has the advantage that ink does not need to be ejected from the liquid ejection head 400. That is, in step S121 shown in FIG. 13, the robot arm 220 may scan the liquid ejection head 400 along the scanning trajectory T0 created by the robot controller 240. Such an operation of the robot 200 and the liquid ejection head 400 is called a head movement operation.

[0089] In step S122, the camera 800 detects the liquid ejection head 400 itself performing the head movement operation. Therefore, it is preferable to place the camera 800 at a position away from the robot 200. Then, the swell amount acquisition unit 914 of the control device 900 detects a relative trajectory T1 of the liquid ejection head 400 with respect to the target object Q.

[0090] In step S122, the waviness amount acquisition unit 914 of the control device 900 acquires the distance between the scanning trajectory T0 and the trajectory T1 in the orthogonal direction D1 as the initial deviation amount in the orthogonal direction D1. In this embodiment, the distance between the scanning trajectory T0 and the trajectory T1 in the orthogonal direction D1 detected at a certain time period is used as the initial deviation amount in the orthogonal direction D1. The certain time period may be, for example, a time period in which the distance period for acquiring the initial deviation amount is about 1 mm.

[0091] Furthermore, the front-rear amount acquisition unit 916 of the control device 900 also acquires the initial amount of deviation in the printing direction D2. In this embodiment, the distance between the ideal state and the actual position in the printing direction D2, detected at a constant time period, is used as the initial amount of deviation in the printing direction D2. Such an operation of the control device 900 is called a deviation amount acquisition operation.

[0092] In step S124, the correction amount setting unit 918 of the control device 900 calculates a correction amount based on the initial misalignment amount obtained by the misalignment amount acquisition operation. Then, in step S124, the calculated correction amount is reflected in the operation of the moving stage 300 in real time. This allows the moving stage 300 to move the liquid ejection head 400 in real time in a direction that reduces the initial misalignment amount. As a result, the trajectory T1 is corrected in real time. Such an operation of the control device 900 is called a correction amount calculation operation.

[0093] In step S114 of this embodiment, the camera 800 detects the corrected trajectory T1. Then, the control device 900 acquires the amount of deviation between the scanning trajectory T0 and the corrected trajectory T1. In this embodiment, the amount of deviation in the orthogonal direction D1 is the "waviness amount," and the amount of deviation in the printing direction D2 is the "front-rear amount." Other than this, this is the same as step S114 in the first embodiment. Also, steps S116 and after are the same as in the first embodiment.

[0094] In the third embodiment as described above, the same effects as in the first embodiment can be obtained. In the third embodiment, the overlap width can be set in the overlap width setting step S100 without actually performing printing. This eliminates the need to prepare a virtual object as a target, and makes it possible to set the overlap width using an object that is actually to be printed.

[0095] 4. Effects of each embodiment As described above, the printing method according to the embodiment is a printing method for printing multiple lines using the liquid ejection head 400 that ejects ink, the robot 200 that moves the liquid ejection head 400 relative to the object Q along the printing direction, and the camera 800 (detection unit) that detects the relative trajectory of the liquid ejection head 400 relative to the object Q, and includes an overlap width setting step S100 and a printing step S200. In the overlap width setting step S100, the camera 800 (detection unit) acquires the amount of undulation of the trajectory in the orthogonal direction D1 (direction orthogonal to the printing direction D2), and sets the overlap width of the trajectory when printing multiple lines based on the acquired amount of undulation. In the printing step S200, the liquid ejection head 400 prints multiple lines on the object Q while moving relatively so that an overlap according to the overlap width occurs in printing the multiple lines.

[0096] With this configuration, the overlap width of the trajectory when printing multiple lines is set based on the amount of undulation of the trajectory of the liquid ejection head 400, so that even if the robot 200 is subject to vibration or the like, it is possible to prevent printing defects such as noticeable gaps or overlaps between lines.

[0097] In addition, the overlap width setting process S100 may be a process in which the camera 800 (detection unit) acquires the front-to-back amount of the trajectory in the printing direction D2, and sets the overlap width of the trajectory when printing multiple lines based on the acquired amount of swell and front-to-back amount.

[0098] According to this configuration, the overlap width of the tracks when printing multiple lines is set taking into account not only the amount of swell but also the amount of front and back movement, thereby making it possible to further reduce the occurrence of printing defects.

[0099] In addition, it is preferable that the object Q when performing the overlap width setting step S100 and the object Q when performing the printing step S200 are different objects. This makes it possible to prevent the object to be printed from being soiled in the overlap width setting step S100.

[0100] Moreover, the overlap width setting step S100 of the printing method according to the first embodiment includes a first pattern printing operation (step S102), a first deviation amount acquisition operation (step S104), a correction amount calculation operation (step S106), a second pattern printing operation (step S108), a second deviation amount acquisition operation (step S110), and an overlap width setting operation (step S116). In the first pattern printing operation, the robot 200 relatively moves the liquid ejection head 400 along the printing direction D2, while the liquid ejection head 400 prints the first pattern P1 on the target Q. In the first deviation amount acquisition operation, the camera 800 (detection unit) detects the first pattern P1, and acquires the deviation amount of the first pattern P1 in the orthogonal direction D1 (direction orthogonal to the printing direction D2) based on the detection result. In the correction amount calculation operation, the amount of relative movement of the liquid ejection head 400 in a direction to reduce the amount of deviation is calculated as the correction amount based on the amount of deviation acquired from the first pattern P1. In the second pattern printing operation, the robot 200 relatively moves the liquid ejection head 400 along the printing direction D2, and while relatively moving the liquid ejection head 400 in the orthogonal direction D1 based on the correction amount, the liquid ejection head 400 prints the second pattern P2 on the target Q. In the second deviation amount acquisition operation, the camera 800 detects the second pattern P2, and acquires the deviation amount of the second pattern P2 in the orthogonal direction D1 based on the detection result. In the overlap width setting operation, the deviation amount acquired from the second pattern P2 is set as the amount of waviness, and the overlap width is set based on the amount of waviness.

[0101] According to this configuration, it is possible to experimentally find an appropriate overlap width for each scanning line, and print multiple lines using that overlap width. This makes it possible to suppress the effect on the print result even if the vibration of the robot 200 changes for each scanning line. In addition, in the first embodiment, the overlap width is set based on the position of the dot d included in the second pattern P2 after the correction amount is reflected. In other words, since the overlap width is set based on the corrected trajectory T2, it is possible to prevent the overlap width from becoming excessively wide, and it is possible to perform higher quality printing at a higher speed.

[0102] Moreover, the overlap width setting step S100 of the printing method according to the second embodiment is a step including a first pattern printing operation (step S102), a first deviation amount acquisition operation (step S104), and an overlap width setting operation (step S116). In the first pattern printing operation, the liquid ejection head 400 prints a first pattern P1 on the target Q while the robot 200 relatively moves the liquid ejection head 400 along the printing direction D2. In the first deviation amount acquisition operation, the camera 800 (detection unit) detects the first pattern P1, and acquires the deviation amount of the first pattern P1 in the orthogonal direction D1 (direction orthogonal to the printing direction D2) based on the detection result. In the overlap width setting operation, the deviation amount acquired from the first pattern P1 is set as the waviness amount, and the overlap width is set based on the waviness amount.

[0103] With this configuration, it is possible to experimentally find an appropriate overlap width for each scanning line and print multiple lines based on that. This makes it possible to suppress the effect on the print result even if the vibration of the robot 200 changes for each scanning line. Furthermore, in the second embodiment, compared to the first embodiment, the printing and detection of the second pattern P2 can be omitted, so the number of steps required to set the overlap width can be reduced, and the overlap width can be set in a shorter time.

[0104] Moreover, the overlap width setting step S100 of the printing method according to the third embodiment is a step including a head moving operation (step S121), a misalignment amount obtaining operation (step S122), and an overlap width setting operation (step S116). In the head moving operation, the robot 200 moves the liquid ejection head 400 along the printing direction D2. In the misalignment amount obtaining operation, the camera 800 (detection unit) detects the trajectory T1 of the liquid ejection head 400, and obtains the misalignment amount in the orthogonal direction D1 (direction orthogonal to the printing direction D2) of the trajectory T1 based on the detection result. In the overlap width setting operation, the misalignment amount obtained from the trajectory T1 is set as the waviness amount, and the overlap width is set based on this waviness amount.

[0105] According to such a configuration, it is possible to experimentally find an appropriate overlap width for each scanning line, and print multiple lines using that overlap width. This makes it possible to suppress the effect on the print result even if the vibration of the robot 200 changes for each scanning line. Also, in the third embodiment, the overlap width can be set from the image of the liquid ejection head 400 without actually performing printing. Therefore, it is not necessary to prepare a virtual object as the target object Q, and it becomes possible to set the overlap width using the object that will actually be printed.

[0106] In addition, in the printing step S200, it is preferable that the liquid ejection head 400 thins out dots in the range OL corresponding to the overlap width and prints multiple lines, thereby preventing an excessive increase in print density in the range OL.

[0107] The robot system (printing device 100) according to the embodiment is an apparatus that prints a plurality of lines on an object Q, and includes a liquid ejection head 400, a robot 200, a camera 800 (detection unit), and a print control unit 910. The liquid ejection head 400 ejects ink (liquid) onto the object Q. The robot 200 has a robot arm 220 that moves the liquid ejection head 400 relative to the object Q along a print direction D2. The camera 800 detects the relative trajectory of the liquid ejection head 400 relative to the object Q. The print control unit 910 controls the operation of the liquid ejection head 400 and the robot 200. The print control unit 910 also includes a swell amount acquisition unit 914 and an overlap width setting unit 920. The swell amount acquisition unit 914 acquires the swell amount of the trajectory in the orthogonal direction D1 (direction perpendicular to the print direction D2). An overlap width setting unit 920 sets the overlap width between the tracks when printing multiple lines, based on the acquired amount of undulation.

[0108] In the printing device 100, the liquid ejection head 400 prints multiple lines on the target Q while the robot 200 moves the liquid ejection head 400 relatively so that overlapping occurs according to the overlapping width when printing multiple lines.

[0109] With this configuration, the overlap width of the trajectory when printing multiple lines is set based on the amount of undulation of the trajectory of the liquid ejection head 400, so that even if the robot 200 is subject to vibration or the like, it is possible to prevent printing defects such as noticeable gaps or overlaps between lines.

[0110] Moreover, the robot 200 preferably has a moving stage 300. The moving stage 300 is provided between the robot arm 220 and the liquid ejection head 400, and moves the liquid ejection head 400 relative to the robot arm 220 in an orthogonal direction D1 (a direction orthogonal to the printing direction D2).

[0111] With this configuration, the moving stage 300 can correct the position of the liquid ejection head 400 with higher accuracy and at higher speed than the robot arm 220. As a result, printing can be performed at higher speed and with higher quality.

[0112] The print control unit 910 preferably also has a front-rear amount acquisition unit 916 that acquires the front-rear amount of the trajectory in the print direction D2.

[0113] With this configuration, the print control unit 910 can set the overlap width taking into account not only the amount of waviness but also the amount of front and rear movement, which can further reduce the occurrence of printing defects.

[0114] Moreover, it is preferable that the print control unit 910 controls the operation of the liquid ejection head 400 so as to thin out dots in a range OL corresponding to the overlap width. With this configuration, an excessive increase in print density in the range OL is suppressed.

[0115] Although the printing method and robot system of the present invention have been described above based on the illustrated embodiment, the printing method and robot system of the present invention are not limited to the embodiment. For example, the printing method of the present invention may be one in which any process or operation for any purpose is added to the embodiment. Furthermore, the robot system of the present invention may be one in which each part of the embodiment is replaced with an arbitrary configuration having the same function, or one in which any component is added to the embodiment. [Explanation of symbols]

[0116] 100...printing device (robot system), 200...robot, 210...base, 220...robot arm, 221...arm, 222...arm, 223...arm, 224...arm, 225...arm, 226...arm, 230...arm drive mechanism, 240...robot controller, 242...arm control section, 244...movement stage controller, 246...storage section, 300...movement stage, 310...base, 320...stage, 320X...X stage, 320Y...Y stage, 330...movement mechanism, 330X...X movement mechanism, 330Y...Y movement mechanism, 340...piezoelectric actuator, 400...liquid ejection head (ink ejection head), 411...ink ejection hole, 420...print controller, 700...fixed member, 800...camera, 900...control device, 910...print control section, 912...print data generation section, 914...ridge a correction amount acquisition unit, 916... a front-rear amount acquisition unit, 918... a correction amount setting unit, 920... an overlap width setting unit, 930... a memory unit, D1... an orthogonal direction, D2... a printing direction, E... an encoder, J1... a joint, J2... a joint, J3... a joint, J4... a joint, J5... a joint, J6... a joint, L1... a first line, L2... a second line, LA... a scanning line, LB... a scanning line, M... a motor, OL... a range, P1... a first pattern, P2... a second pattern, Q... an object, S 100...width setting process, S102...step, S104...step, S106...step, S108...step, S110...step, S114...step, S116...step, S118...step, S120...step, S121...step, S122...step, S124...step, S200...printing process, T0...scanning trajectory, T1...locus, T2...locus, d...dot, da...dot, db...dot

Claims

1. A liquid ejection head that ejects liquid, and a printing method for printing a liquid onto an object by moving the liquid ejection head along a printing direction. a robot that moves the liquid ejection head relative to the object; and a relative trajectory of the liquid ejection head relative to the object. A printing method for printing multiple lines using a detection unit that detects The detection unit acquires the amount of waviness of the locus in a direction perpendicular to the printing direction, Based on the amount of undulation thus determined, the overlap width of the locus when printing multiple lines is set. an overlap width setting step; The liquid ejection head is configured to overlap the ink droplets in accordance with the overlap width when printing multiple lines. a printing step in which the printer prints multiple lines on the target object while the printer moves relative to the target object; A printing method comprising:

2. The overlap width setting step includes the step of: and based on the acquired swell amount and front-back amount, 2. The printing method according to claim 1, further comprising the step of setting the overlap width of the recording locus.

3. The object when the overlap width setting step is performed and before the printing step is performed 2. The printing method according to claim 1, wherein the objects are different objects.

4. The overlap width setting step includes: While the robot relatively moves the liquid ejection head along the printing direction, a first pattern printing operation in which the liquid ejection head prints a first pattern on an object; The detection unit detects the first pattern, and based on the detection result, a first deviation amount acquisition operation for acquiring a deviation amount in a direction perpendicular to the printing direction; Based on the amount of deviation acquired from the first pattern, a correction amount calculation operation for calculating an amount of relative movement of the liquid ejection head as a correction amount; the robot relatively moves the liquid ejection head along the printing direction; and The liquid ejection head is relatively moved in a direction perpendicular to the printing direction based on the correction amount. a second pattern printing step in which the liquid ejection head prints a second pattern on the object while moving the liquid ejection head; Action and The detection unit detects the second pattern, and based on the detection result, a second deviation amount acquisition operation for acquiring a deviation amount in a direction perpendicular to the printing direction; The deviation amount acquired from the second pattern is set as the amount of waviness, and a calculation is performed based on the amount of waviness. an overlap width setting operation for setting the overlap width; The printing method according to claim 1 , comprising the steps of:

5. The overlap width setting step includes: While the robot relatively moves the liquid ejection head along the printing direction, a first pattern printing operation in which the liquid ejection head prints a first pattern on an object; The detection unit detects the first pattern, and based on the detection result, a first deviation amount acquisition operation for acquiring a deviation amount in a direction perpendicular to the printing direction; The deviation amount acquired from the first pattern is set as the amount of waviness, and a calculation is performed based on the amount of waviness. an overlap width setting operation for setting the overlap width; The printing method according to claim 1 , comprising the steps of:

6. The overlap width setting step includes: The robot moves the liquid ejection head relatively along the printing direction. Movement and The detection unit detects the trajectory of the liquid ejection head, and based on the detection result, a misalignment amount acquisition operation for acquiring a misalignment amount in a direction perpendicular to the printing direction; The deviation amount acquired from the trajectory is set as the swell amount, and based on the swell amount, an overlap width setting operation for setting an overlap width; The printing method according to claim 1 , comprising the steps of:

7. A step of thinning out dots in a range corresponding to the overlap width, The printing method according to any one of claims 1 to 6.

8. thinning out dots in a range corresponding to the overlap width based on gradation dispersion; The printing method according to claim 7.

9. In the overlap width setting step, when the swell amount is a first swell amount, the overlap width is set to a first When the swell amount is a second swell amount that is greater than the first swell amount, setting the overlapping width to a second overlapping width that is wider than the first overlapping width; The printing method according to any one of claims 1 to 6.

10. A step of determining a line feed width of a scanning line of the liquid ejection head in accordance with the overlap width. The printing method according to any one of claims 1 to 6.

11. A robotic system for printing multiple lines on an object, a liquid ejection head that ejects liquid; A robotic actuator that moves the liquid ejection head relative to the object in the printing direction. a robot having a robot arm; a detection unit that detects a relative trajectory of the liquid ejection head with respect to an object; a print control unit that controls the operation of the liquid ejection head and the robot; Equipped with The print control unit a swell amount acquisition unit that acquires the swell amount of the locus in a direction perpendicular to the printing direction; 、 Based on the acquired amount of undulation, the overlap width between the loci when printing multiple lines is determined. an overlap width setting unit that sets and The robot moves forward so that overlapping occurs according to the overlap width when printing multiple lines. While the liquid ejection head is relatively moved, the liquid ejection head prints a plurality of lines on the target. A robot system that performs printing.

12. A liquid ejection head that ejects liquid; a robot that moves the liquid ejection head relative to an object in a printing direction; 、 a detection unit that detects a relative trajectory of the liquid ejection head with respect to an object, The detection unit acquires the amount of waviness of the locus in a direction perpendicular to the printing direction, based on the amount of undulation thus determined, an overlap width of the locus when printing a plurality of lines is set; The liquid ejection head is configured to overlap the ink droplets in accordance with the overlap width when printing multiple lines. The printer moves relative to the object, printing multiple lines on the object. A printing device characterized by:

Images