Control method and 3D object printing apparatus

Abstract

Reduce the time required to create print tracks. [Solution] A control method for controlling the operation of a three-dimensional object printing apparatus having a liquid discharge head for discharging liquid toward a workpiece and a moving mechanism for moving the liquid discharge head, the method comprising: a trajectory information generation step for generating trajectory information relating to the movement trajectory of the moving mechanism moving the liquid discharge head; a correspondence information generation step for generating correspondence information that associates the trajectory information with head information relating to the liquid discharge head and first image information relating to a first image to be printed; a storage step for storing the correspondence information; and a print data generation step for generating print data for printing a second image based on the correspondence information and second image information relating to a second image to be printed.

Description

Technical Field

[0001] The present disclosure relates to a control method and a three-dimensional object printing apparatus.

Background Art

[0002] Conventionally, an apparatus for performing printing on the surface of a three-dimensional workpiece by an inkjet method has been known. For example, in Patent Document 1, while changing the position and orientation of a head by the operation of a robot based on printing path information, ink ejected from nozzles is applied to a workpiece by the operation of the head based on printing data, thereby performing printing on the workpiece. In Patent Document 1, the printing path information is generated based on workpiece data indicating the shape of the workpiece and nozzle surface data indicating the shape of the nozzle surface.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the apparatus described in Patent Document 1, when generating printing path information, it is necessary to associate the movement trajectory of the head, the image information that is the source of the printing data, and the nozzle surface data. Such association imposes a high processing load. Therefore, every time the image to be printed is changed, performing such association causes a problem that the time required for printing increases.

Means for Solving the Problems

[0005] To solve the above problems, one aspect of the control method of the present disclosure is a control method for controlling the operation of a three-dimensional object printing apparatus having a liquid discharge head for discharging liquid toward a workpiece and a moving mechanism for moving the liquid discharge head, the method comprising: a trajectory information generation step of generating trajectory information relating to the movement trajectory of the moving mechanism moving the liquid discharge head; a correspondence information generation step of generating correspondence information that associates the trajectory information with head information relating to the liquid discharge head and first image information relating to a first image to be printed; a storage step of storing the correspondence information; and a print data generation step of generating print data for printing a second image based on the correspondence information and second image information relating to a second image to be printed.

[0006] One embodiment of the three-dimensional object printing apparatus of the present disclosure comprises a liquid discharge head for discharging liquid toward a workpiece, and a moving mechanism for moving the liquid discharge head, wherein the moving mechanism generates trajectory information relating to the movement trajectory of the liquid discharge head, generates correspondence information relating the trajectory information, head information relating to the liquid discharge head, and first image information relating to a first image to be printed, and generates print data for printing the second image based on the correspondence information and second image information relating to a second image to be printed.

[0007] Another aspect of the control method of the present disclosure is a control method for controlling the operation of a three-dimensional object printing apparatus having a liquid discharge head for discharging liquid toward a workpiece and a moving mechanism for moving the liquid discharge head, the method comprising: a trajectory information generation step of generating trajectory information relating to a moving trajectory by which the moving mechanism moves the liquid discharge head; a first printing step of printing a first image; and a second printing step of printing a second image different from the first image, wherein in both the first printing step and the second printing step, the moving mechanism moves the liquid discharge head along the moving trajectory.

[0008] One embodiment of the three-dimensional object printing apparatus of the present disclosure includes a liquid discharge head for discharging liquid toward a workpiece, a moving mechanism for moving the liquid discharge head, a storage unit for storing correspondence information that associates trajectory information relating to the movement trajectory of the moving mechanism for moving the liquid discharge head, head information relating to the liquid discharge head, and first image information relating to a first image to be printed, and generates print data for printing the second image based on the correspondence information and second image information relating to a second image to be printed. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic perspective view showing the three-dimensional object printing apparatus according to the embodiment. [Figure 2] This is a block diagram showing the electrical configuration of a three-dimensional object printing apparatus according to an embodiment. [Figure 3] This is a perspective view showing the general configuration of the head unit. [Figure 4] This diagram shows the flow of the control method according to the embodiment. [Figure 5] This is an explanatory diagram for the generation of a moving trajectory. [Figure 6] This is an explanatory diagram for generating correspondence information. [Figure 7] This is an explanatory diagram of the movement track and printing area. [Figure 8] This figure shows an example of correspondence information. [Figure 9] This is an explanatory diagram of the print data for printing the first image. [Figure 10] This is an explanatory diagram illustrating another example of print data for printing the first image. [Figure 11] This is an explanatory diagram of the print data for printing the second image. [Figure 12] This is an explanatory diagram illustrating another example of print data for printing the second image. [Figure 13] This is an explanatory diagram of print data for multi-color printing. [Modes for carrying out the invention]

[0010] Hereinafter, preferred embodiments according to the present disclosure will be described with reference to the accompanying drawings. Note that in the drawings, the dimensions and scales of each part are appropriately different from the actual ones, and there are also some parts schematically shown for easy understanding. Also, the scope of the present disclosure is not limited to these forms unless there is a description specifically limiting the present disclosure in the following description.

[0011] Hereinafter, for the sake of convenience of explanation, the X-axis, Y-axis, and Z-axis that intersect each other will be appropriately used for the explanation. Also, hereinafter, one direction along the X-axis is the X1 direction, and the direction opposite to the X1 direction is the X2 direction. Similarly, the directions opposite to each other along the Y-axis are the Y1 direction and the Y2 direction. Also, the directions opposite to each other along the Z-axis are the Z1 direction and the Z2 direction.

[0012] Here, the X-axis, Y-axis, and Z-axis correspond to the coordinate axes of the world coordinate system set in the space where the robot 2 described later is installed. Typically, the Z-axis is a vertical axis, and the Z2 direction corresponds to the downward direction in the vertical direction. In this world coordinate system, a base coordinate system based on the position of the base 210 of the robot 2 described later is associated by calibration. Hereinafter, for the sake of convenience, a case where the world coordinate system is used as the robot coordinate system to control the operation of the robot 2 will be exemplified.

[0013] Note that the Z-axis does not have to be a vertical axis. Also, the X-axis, Y-axis, and Z-axis typically intersect each other at right angles, but are not limited to this, and may not intersect at right angles. For example, the X-axis, Y-axis, and Z-axis may intersect each other at an angle within the range of 80° or more and 100° or less.

[0014] 1-1. Outline of the three-dimensional object printing apparatus FIG. 1 is a perspective view showing an outline of a three-dimensional object printing apparatus 1 according to an embodiment. The three-dimensional object printing apparatus 1 is an apparatus that performs printing on the surface of a three-dimensional workpiece W by an inkjet method.

[0015] The workpiece W has a surface WF to be printed. In the example shown in FIG. 1, the workpiece W is a hemisphere, and the surface WF is a convex hemispherical surface. During printing, the workpiece W is supported, if necessary, by, for example, a predetermined installation table, the hand of a robot other than the robot 2 described later, or a structure such as a conveyor. Note that the size, shape, or installation posture of the workpiece W is not limited to the example shown in FIG. 1 and is arbitrary.

[0016] As shown in FIG. 1, the three-dimensional object printing apparatus 1 includes a robot 2, a head unit 3, and a controller 5. The robot 2 is an example of a "moving mechanism". First, these will be briefly described in order below.

[0017] The robot 2 is a robot that changes the position and orientation of the head unit 3 in the world coordinate system and moves the head 3a described later. In the example shown in FIG. 1, the robot 2 is a so-called six-axis vertical articulated robot.

[0018] As shown in FIG. 1, the robot 2 includes a base 210 and an arm 220.

[0019] The base 210 is a pedestal that supports the arm 220. In the example shown in FIG. 1, the base 210 is fixed to an installation surface such as a floor surface or a base facing in the Z1 direction by screwing or the like. Note that the installation surface to which the base 210 is fixed may be a surface facing any direction and is not limited to the example shown in FIG. 1. For example, it may be a surface of a wall, a ceiling, a movable cart, or the like.

[0020] The arm 220 is a six-axis robot arm having a proximal end attached to the base 210 and a distal end that changes its position and orientation three-dimensionally with respect to the proximal end. Specifically, the arm 220 includes arms 221, 222, 223, 224, 225, and 226, also referred to as links, which are connected in this order.

[0021] Arm 221 is connected to the base 210 via joint 230_1 so as to be rotatable around pivot axis O1. Arm 222 is connected to arm 221 via joint 230_2 so as to be rotatable around pivot axis O2. Arm 223 is connected to arm 222 via joint 230_3 so as to be rotatable around pivot axis O3. Arm 224 is connected to arm 223 via joint 230_4 so as to be rotatable around pivot axis O4. Arm 225 is connected to arm 224 via joint 230_5 so as to be rotatable around pivot axis O5. Arm 226 is connected to arm 225 via joint 230_6 so as to be rotatable around pivot axis O6.

[0022] Each of the joints 230_1 to 230_6 is a mechanism that rotatably connects one of two adjacent members from the base 210 and arms 221 to 226 to the other. In the following, each of the joints 230_1 to 230_6 may be referred to as joint 230.

[0023] Although not shown in Figure 1, each of the joints 230_1 to 230_6 is provided with a drive mechanism that rotates one of the two corresponding adjacent members relative to the other. This drive mechanism includes, for example, a motor that generates the driving force for the rotation, a reduction gear that reduces and outputs the driving force, and an encoder such as a rotary encoder that detects the amount of movement, such as the angle of rotation. The assembly of these drive mechanisms for joints 230_1 to 230_6 corresponds to the arm drive mechanism 2a shown in Figure 2, which will be described later.

[0024] The pivot axis O1 is an axis perpendicular to the mounting surface (not shown) to which the base 210 is fixed. The pivot axis O2 is an axis perpendicular to the pivot axis O1. The pivot axis O3 is an axis parallel to the pivot axis O2. The pivot axis O4 is an axis perpendicular to the pivot axis O3. The pivot axis O5 is an axis perpendicular to the pivot axis O4. The pivot axis O6 is an axis perpendicular to the pivot axis O5.

[0025] Furthermore, regarding these pivot axes, "perpendicular" includes not only cases where the angle between the two pivot axes is exactly 90°, but also cases where the angle between the two pivot axes deviates from 90° by approximately ±5°. Similarly, "parallel" includes not only cases where the two pivot axes are exactly parallel, but also cases where one of the two pivot axes is tilted relative to the other by approximately ±5°.

[0026] Of the arms 221-226 of robot 2 described above, the arm 226, which is located at the very end, is fitted with the head unit 3 as an end effector, fixed in place by screws or the like.

[0027] The head unit 3 is an assembly having a head 3a that ejects ink, which is an example of a "liquid," toward the workpiece W. The head 3a is an example of a "liquid ejection head." In this embodiment, the head unit 3 has an energy ejection unit 3c in addition to the head 3a. Details of the head unit 3 will be described later with reference to Figure 3.

[0028] The ink is not particularly limited and includes, for example, an aqueous ink obtained by dissolving a colorant such as a dye or pigment in an aqueous solvent, a curable ink using a curable resin such as an ultraviolet-curable type, and a solvent-based ink obtained by dissolving a colorant such as a dye or pigment in an organic solvent. Among these, curable inks are preferably used. The curable ink is not particularly limited and may be any of the following: thermosetting type, photocuring type, linear curing type, and electron beam curing type, but a photocuring type such as an ultraviolet-curing type is preferred. The ink is not limited to a solution and may also be an ink in which a colorant is dispersed as a dispersed phase in a dispersion medium. Furthermore, the ink is not limited to an ink containing a colorant and may also be an ink containing conductive particles such as metal particles for forming wiring, a clear ink, or a treatment liquid for surface treatment of the workpiece W.

[0029] Controller 5 is a robot controller that controls the movement of robot 2. Computer 7 is a desktop or notebook computer with a program installed, and it controls the movement of head unit 3. The electrical configuration of the 3D object printing apparatus 1 will be described below, including a detailed explanation of controller 5 and computer 7, based on Figure 2.

[0030] 1-2. Electrical configuration of a three-dimensional object printing device Figure 2 is a block diagram showing the electrical configuration of a three-dimensional object printing apparatus 1 according to an embodiment. Figure 2 shows the electrical components among the components of the three-dimensional object printing apparatus 1. As shown in Figure 2, in addition to the components shown in Figure 1, the three-dimensional object printing apparatus 1 includes a control module 6 that is communicatively connected to the controller 5, and a computer 7 that is communicatively connected to the controller 5 and the control module 6. Here, the controller 5, the control module 6, and the computer 7 constitute a control unit 8.

[0031] Furthermore, the electrical components shown in Figure 2 may be divided as appropriate, some of which may be included in other components, or may be integrated with other components. For example, some or all of the functions of the controller 5 or control module 6 may be implemented by the computer 7, or by other external devices such as a PC (personal computer) connected to the controller 5 via a network such as a LAN (Local Area Network) or the Internet.

[0032] The controller 5 has the function of controlling the drive of the robot 2 and the function of generating a signal D3 to synchronize the ink ejection operation of the head unit 3 with the operation of the robot 2.

[0033] The controller 5 includes a memory circuit 5a and a processing circuit 5b.

[0034] The memory circuit 5a stores various programs executed by the processing circuit 5b and various data processed by the processing circuit 5b. The memory circuit 5a includes, for example, one or both of the following semiconductor memories: a volatile memory such as RAM (Random Access Memory) and a non-volatile memory such as ROM (Read Only Memory), EEPROM (Electrically Erasable Programmable Read-Only Memory), or PROM (Programmable ROM). Note that part or all of the memory circuit 5a may be included in the processing circuit 5b.

[0035] The memory circuit 5a stores the orbital information Da.

[0036] Trajectory information Da is information about the movement trajectory RU by which the robot 2 moves the head 3a, and includes information indicating the position and orientation of the head 3a along the path it should move during the execution of a printing operation. Trajectory information Da is expressed, for example, using coordinate values ​​in the work coordinate system, base coordinate system, or world coordinate system, with the workpiece W as the reference point. Trajectory information Da is generated by the processing circuit 7b and input from the processing circuit 7b to the memory circuit 5a. When trajectory information Da is expressed using coordinate values ​​in the work coordinate system, it is converted from work coordinate system coordinate values ​​to base coordinate system or world coordinate system coordinate values ​​before being used to control the movement of the robot 2.

[0037] The processing circuit 5b controls the operation of the robot 2's arm drive mechanism 2a based on the trajectory information Da, and also generates the signal D3. The processing circuit 5b includes, for example, one or more processors such as CPUs (Central Processing Units). The processing circuit 5b may also include a programmable logic device such as an FPGA (field-programmable gate array) instead of a CPU, or in addition to a CPU.

[0038] Here, the arm drive mechanism 2a is an assembly of the drive mechanisms for the aforementioned joints 230_1 to 230_6, and each joint 230 has a motor for driving the joint of the robot 2 and an encoder for detecting the rotation angle of the joint of the robot 2.

[0039] The processing circuit 5b performs inverse kinematics calculations, which convert trajectory information Da into motion variables such as rotation angle and rotation speed of each joint 230 of the robot 2. Then, the processing circuit 5b outputs a control signal Sk1 based on the output D1 from each encoder of the arm drive mechanism 2a so that the actual motion variables such as rotation angle and rotation speed of each joint 230 match the results of the aforementioned calculation based on trajectory information Da. The control signal Sk1 is a signal for controlling the drive of the motors of the arm drive mechanism 2a. Here, the control signal Sk1 is corrected by the processing circuit 5b as needed based on the output from acceleration sensors and distance sensors (not shown).

[0040] Furthermore, the processing circuit 5b generates a signal D3 based on the output D1 from at least one of the multiple encoders of the arm drive mechanism 2a. For example, the processing circuit 5b generates a trigger signal D3 that includes a pulse at a timing when the output D1 from one of the multiple encoders reaches a predetermined value.

[0041] The control module 6 is a circuit that controls the ink ejection operation of the head unit 3 based on the signal D3 output from the controller 5 and the print data Img from the computer 7. The control module 6 includes a timing signal generation circuit 6a, a power supply circuit 6b, a control circuit 6c, and a drive signal generation circuit 6d.

[0042] The timing signal generation circuit 6a generates a timing signal PTS based on signal D3. The timing signal generation circuit 6a is composed of a timer that, for example, starts generating the timing signal PTS when signal D3 is detected.

[0043] The power supply circuit 6b receives power from a commercial power source (not shown) and generates various predetermined potentials. The generated potentials are supplied to the control module 6 and the head unit 3 as appropriate. For example, the power supply circuit 6b generates a power supply potential VHV and an offset potential VBS. The offset potential VBS is supplied to the head unit 3. The power supply potential VHV is supplied to the drive signal generation circuit 6d.

[0044] The control circuit 6c generates a control signal SI, a waveform specification signal dCom, a latch signal LAT, a clock signal CLK, and a change signal CNG based on the timing signal PTS. These signals are synchronized with the timing signal PTS. Of these signals, the waveform specification signal dCom is input to the drive signal generation circuit 6d, and the other signals are input to the switch circuit 3e of the head unit 3.

[0045] The control signal SI is a digital signal used to specify the operating state of the drive element of the head 3a of the head unit 3. Specifically, the control signal SI is a signal used to specify whether or not to supply the drive signal Com, described below, to the drive element based on the print data Img. This specification, for example, specifies whether or not to eject ink from the nozzle corresponding to the drive element, or specifies the amount of ink ejected from the nozzle. The waveform specification signal dCom is a digital signal used to define the waveform of the drive signal Com. The latch signal LAT and the change signal CNG are used in conjunction with the control signal SI to define the timing of ink ejection from the nozzle by defining the driving timing of the drive element. The clock signal CLK is a reference clock signal synchronized with the timing signal PTS.

[0046] The control circuit 6c described above includes, for example, one or more processors such as CPUs. The control circuit 6c may also include a programmable logic device such as an FPGA instead of a CPU, or in addition to a CPU.

[0047] The drive signal generation circuit 6d is a circuit that generates a drive signal Com for driving each drive element of the head 3a of the head unit 3. Specifically, the drive signal generation circuit 6d includes, for example, a DA conversion circuit and an amplification circuit. In the drive signal generation circuit 6d, the DA conversion circuit converts the waveform specification signal dCom from the control circuit 6c from a digital signal to an analog signal, and the amplification circuit amplifies the analog signal using the power supply potential VHV from the power supply circuit 6b to generate the drive signal Com. Here, among the waveforms included in the drive signal Com, the signal of the waveform that is actually supplied to the drive element is the drive pulse PD. The drive pulse PD is supplied from the drive signal generation circuit 6d to the drive element via the switch circuit 3e of the head unit 3.

[0048] Here, the switch circuit 3e is a circuit that includes a switching element that, based on the control signal SI, switches whether or not to supply at least a portion of the waveform included in the drive signal Com as a drive pulse PD.

[0049] Computer 7 has the function of generating orbital information Da, the function of supplying information such as orbital information Da to the controller 5, and the function of supplying information such as print data Img to the control module 6. In addition to these functions, computer 7 in this embodiment also has the function of controlling the drive of the energy emission unit 3c.

[0050] Computer 7 has a memory circuit 7a and a processing circuit 7b. The memory circuit 7a is an example of a "memory unit". In addition, although not shown in the figures, computer 7 has an input device such as a keyboard or mouse that accepts user input. Computer 7 may also have a display device such as a liquid crystal panel that displays information necessary for generating orbit information Da.

[0051] The memory circuit 7a stores various programs executed by the processing circuit 7b and various data processed by the processing circuit 7b. The memory circuit 7a includes, for example, one or both of semiconductor memories, such as volatile memory like RAM and non-volatile memory like ROM, EEPROM, or PROM. Part or all of the memory circuit 7a may be included in the processing circuit 7b.

[0052] The memory circuit 7a stores trajectory information Da, work information Dw, head information Db, first image information Dg1, second image information Dg2, correspondence information Dc, instruction information Dd, print data Img1, Img2, and program PR.

[0053] Work information Dw is data representing the shape of at least a part of the workpiece W. Specifically, work information Dw is 3D data such as STL (Standard Triangulated Language) format that represents the shape of workpiece W using multiple polygons. Work information Dw can be obtained, for example, by converting CAD (computer-aided design) data showing the 3D shape of workpiece W as needed, or by measuring the shape of workpiece W using a known 3D shape measurement method. Work information Dw may be represented using coordinate values ​​of the workpiece coordinate system, or by point cloud data using coordinate values ​​of the base coordinate system or world coordinate system. Furthermore, work information Dw may be represented by mathematical formulas, and the format of work information Dw can be converted as appropriate as needed.

[0054] The head information Db contains information about the head 3a. Specifically, the head information Db is information for representing the multiple nozzles N of the head 3a as virtual objects in the virtual space VS, and includes information such as the model of the head 3a, the number of nozzles N, the nozzle number for identifying each nozzle N, the position of each nozzle N, the ink color, and the position of the tool center point TCP, which will be described later.

[0055] The first image information Dg1 is information relating to the first image G1, which will be printed (described later). More specifically, the first image information Dg1 is information that represents the first image G1 in two dimensions, and is, for example, image data created by image editing software. The data format of the first image information Dg1 is not particularly limited, but may be in the form of a page description language such as PostScript, PDF (Portable Document Format), or XPS (XML Paper Specification), or image data in various vector or raster formats.

[0056] The second image information Dg2 is information relating to the second image G2, which will be printed (described below). More specifically, the second image information Dg2 is information that shows the second image G2, which is different from the first image G1, in two dimensions, and is, for example, image data created by image editing software. The data format of the second image information Dg2 is not particularly limited, but may be in the form of a page description language such as PostScript, PDF (Portable Document Format), or XPS (XML Paper Specification), or image data in various vector or raster formats.

[0057] Correspondence information Dc is information that associates trajectory information Da, head information Db, and first image information Dg1. Specifically, correspondence information Dc indicates which nozzle N in which pass and shot should be used to print the color information corresponding to which pixel in the first image G1 indicated by the first image information Dg1. Details of correspondence information Dc will be explained later with reference to Figure 8.

[0058] Instruction information Dd is information about user instructions. These instructions are, for example, setting instructions regarding the size of overlapping areas such as the first overlapping area OV1a described later, and are used to adjust these overlapping areas.

[0059] Print data Img1 is print data Img for printing the first image G1 onto the workpiece W, and shows images obtained by dividing the first image G1 according to the print path (path) of the movement trajectory indicated by the trajectory information Da.

[0060] Print data Img2 is print data Img for printing the second image G2 onto the workpiece W, and shows images obtained by dividing the second image G2 according to the print path (path) of the movement trajectory indicated by the trajectory information Da.

[0061] Program PR is a program for executing the control method described later.

[0062] The processing circuit 7b implements the aforementioned functions by executing a program such as program PR. The processing circuit 7b includes, for example, one or more processors such as CPUs. The processing circuit 7b may also include a programmable logic device such as an FPGA instead of a CPU, or in addition to a CPU.

[0063] The processing circuit 7b implements various functions for the control method described later by executing the program PR. Specifically, as will be described in detail later, the processing circuit 7b generates print data Img1 when printing the first image G1 indicated by the first image information Dg1. At this time, the processing circuit 7b generates print data Img1 based on the work information Dw, the first image information Dg1, and the head information Db, and in this generation process, it generates trajectory information Da and correspondence information Dc. The processing circuit 7b also generates print data Img2 when printing the second image G2 indicated by the second image information Dg2. At this time, if the print trajectory indicated by the trajectory information Da is available when printing the second image G2, for example, if the shape of the work W is the same as when printing the first image G1, the processing circuit 7b generates print data Img2 based on the correspondence information Dc and the second image information Dg2 without generating new trajectory information Da.

[0064] Thus, since the correspondence information Dc generated as intermediate data during the generation of the print data Img1 for the first image G1 is used to generate the print data Img2 for the second image G2, it becomes unnecessary to create a movement trajectory RU for each image, and as a result, the time required to create the movement trajectory RU can be reduced. Details of this control method will be explained later with reference to Figures 4 to 13.

[0065] As described above, the robot 2 is driven based on the trajectory information Da, and the head 3a is driven based on the print data Img and signal D3, thereby performing the printing operation. During the printing operation, the robot 2 changes the position and orientation of the head 3a based on the trajectory information Da, and the head 3a ejects ink from the head 3a towards the workpiece W at appropriate timings based on the print data Img and signal D3. As a result, an image based on the print data Img is formed on the workpiece W.

[0066] 1-3. Head Unit Configuration Figure 3 is a perspective view showing the schematic configuration of the head unit 3. For convenience, the following explanation will use the intersecting a-axis, b-axis, and c-axis as appropriate. In the following explanation, one direction along the a-axis is the a1 direction, and the direction opposite to the a1 direction is the a2 direction. Similarly, the opposite directions along the b-axis are the b1 direction and the b2 direction. Also, the opposite directions along the c-axis are the c1 direction and the c2 direction.

[0067] Here, axes a, b, and c correspond to the coordinate axes of the tool coordinate system set in the head unit 3, and their relative position and orientation with respect to the world coordinate system or robot coordinate system changes with the movement of the robot 2 described above. In the example shown in Figure 3, axis c is the axis parallel to the rotation axis O6 described above. Axes a, b, and c are typically orthogonal to each other, but are not limited to this; for example, they may intersect at an angle within the range of 80° to 100°. The tool coordinate system and the base coordinate system or robot coordinate system are associated by calibration.

[0068] In the following, the a-axis may be referred to as the "roll axis," the b-axis as the "pitch axis," and the c-axis as the "yaw axis." Furthermore, rotation around the a-axis may be referred to as "roll," rotation around the b-axis as "pitch," and rotation around the c-axis as "yaw."

[0069] The tool coordinate system is set relative to the tool center point TCP. Therefore, the position and orientation of the head 3a are defined relative to the tool center point TCP. In this embodiment, in the example shown in Figure 3, the tool center point TCP is located in a space at a predetermined distance from the center of the nozzle row NL in the b-axis direction of the head 3a in the ink ejection direction DE. Note that the position of the tool center point TCP is not limited to the example shown in Figure 3, and may be, for example, the center of the nozzle surface FN.

[0070] As described above, the head unit 3 has a head 3a and an energy emission unit 3c. These are supported by a support 3f, indicated by the dashed line in Figure 3. In the example shown in Figure 3, the head unit 3 has one head 3a, but this number is not limited to the example shown in Figure 3 and may be two or more. For example, the head unit 3 may have multiple heads 3a with different ink colors. In addition to the head 3a and the energy emission unit 3c, the head unit 3 may also have, for example, a pressure regulating valve to adjust the pressure of the ink in the head 3a. The energy emission unit 3c may be provided as needed or omitted.

[0071] The support 3f is made of, for example, a metal material and is essentially a rigid body. In Figure 3, the support 3f is shown as a flattened box shape, but the shape of the support 3f is not particularly limited and can be arbitrary.

[0072] The support 3f described above is attached to the arm 226. Therefore, the head 3a and the energy emitter 3c are collectively supported by the arm 226 by the support 3f. As a result, the relative positions of the head 3a and the energy emitter 3c with respect to the arm 226 are fixed. In the example shown in Figure 3, the energy emitter 3c is positioned in the a2 direction relative to the head 3a.

[0073] Head 3a is a liquid ejection head and has a nozzle surface FN and a plurality of nozzles N that open into the nozzle surface FN. The nozzle surface FN is the nozzle surface through which the nozzles N open. In the example shown in Figure 3, the direction normal to the nozzle surface FN, i.e., the direction DE of ink ejection from the nozzles N, is the c2 direction. Strictly speaking, the ejection direction DE and the c2 direction may not be parallel due to the inertia or airflow caused by the movement of the robot 2, but such errors are not considered in this embodiment.

[0074] The multiple nozzles N are divided into a first nozzle row NL1 and a second nozzle row NL2, which are spaced apart from each other in the direction along the a-axis. Each of the first nozzle row NL1 and the second nozzle row NL2 is a set of multiple nozzles N arranged linearly in the nozzle row direction DN, which is the direction along the b-axis. Here, the elements associated with each nozzle N in the first nozzle row NL1 and the elements associated with each nozzle N in the second nozzle row NL2 in the head 3a are configured to be approximately symmetrical with respect to each other in the direction along the a-axis.

[0075] However, the positions of multiple nozzles N in the first nozzle row NL1 and multiple nozzles N in the second nozzle row NL2 along the b-axis may coincide or differ. Also, elements related to each nozzle N in either the first nozzle row NL1 or the second nozzle row NL2 may be omitted. Below, an example is given in which the positions of multiple nozzles N in the first nozzle row NL1 and multiple nozzles N in the second nozzle row NL2 along the b-axis coincide.

[0076] In the following, the entirety of the first nozzle row NL1 and the second nozzle row NL2 may be referred to as nozzle row NL. Nozzle row NL includes the first nozzle row NL1 and the second nozzle row NL2.

[0077] Although not shown, the print head 3a has a piezoelectric element, which is a driving element, and a cavity for containing ink for each nozzle N. Ink is supplied to the print head 3a from an ink tank (not shown). The piezoelectric element changes the pressure in the cavity corresponding to the piezoelectric element, thereby causing ink to be ejected from the nozzle N corresponding to the cavity in the ejection direction DE. Alternatively, instead of the piezoelectric element, a heater that heats the ink in the cavity may be used as the driving element for ejecting ink from the nozzle N.

[0078] The energy emission unit 3c emits energy such as light, heat, electron beams, or radiation to cure or solidify the ink on the workpiece W. For example, if the ink is UV-curable, the energy emission unit 3c is composed of a light-emitting element such as an LED (light-emitting diode) that emits ultraviolet light. The energy emission unit 3c may also have optical components such as lenses to adjust the direction or range of energy emission.

[0079] 1-4. Control Method Figure 4 is a diagram showing the flow of a control method according to an embodiment. This control method is a method for controlling the operation of the three-dimensional object printing apparatus 1, and is realized by the processing circuit 7b executing the program PR described above. As shown in Figure 4, this control method includes a first image information acquisition step S1, a trajectory information generation step S2, a corresponding information generation step S3, a storage step S4, a first print data generation step S5, a first print step S6, decision steps S7, S8, S9, a second image information acquisition step S10, a corresponding information acquisition step S11, an instruction acquisition step S12, an overlapping area adjustment step S13, a second print data generation step S14, a second print step S15, and a decision step S16. The second print data generation step S14 is an example of a "print data generation step".

[0080] In this control method, first, in the first image information acquisition step S1, the processing circuit 7b acquires first image information Dg1. This acquisition is performed, for example, by the processing circuit 7b reading the first image information Dg1 from the memory circuit 7a or the like. In addition to acquiring the first image information Dg1, head information Db, work information Dw, and set values ​​are also acquired in the first image information acquisition step S1. The head information Db and work information Dw are acquired, for example, by the processing circuit 7b reading the head information Db and work information Dw from the memory circuit 7a or the like. The set values ​​include, for example, the set value of the distance PG between the head 3a and the work W, and the set value of the mask pattern. The acquisition of these set values ​​is performed, for example, in response to input from the user. The set values ​​may also be automatically set by the processing circuit 7b according to the known distance PG between the head 3a and the work W, or they may be set by user input. Furthermore, this setting includes a user-specified tolerance range for the difference between the distance PG corresponding to the main dot (described later) and the distance PG of each subdot. This setting may also include information regarding the type of the first image G1, such as line drawings or photographs.

[0081] Following the first image information acquisition step S1, in the trajectory information generation step S2, the processing circuit 7b generates trajectory information Da based on the first image information Dg1, head information Db, workpiece information Dw, and set values ​​acquired in the first image information acquisition step S1. The generated trajectory information Da is stored in the memory circuit 7a. Details of the trajectory information generation step S2 will be explained later with reference to Figure 5.

[0082] Following the trajectory information generation process S2, in the corresponding information generation process S3, the processing circuit 7b generates corresponding information Dc based on the trajectory information Da, the first image information Dg1, the head information Db, and the workpiece information Dw. Details of the corresponding information generation process S3 will be explained later with reference to Figures 6 to 8.

[0083] After the corresponding information generation step S3, in the storage step S4, the processing circuit 7b causes the corresponding information Dc to be stored in the storage circuit 7a.

[0084] Following the storage step S4, in the first print data generation step S5, the processing circuit 7b generates print data Img1 based on the correspondence information Dc and the first image information Dg1. The generated print data Img1 is stored in the storage circuit 7a. Details of the first print data generation step S5 will be explained later with reference to Figures 9 and 10. Note that the first print data generation step S5 may be performed before the storage step S4, or in parallel with the storage step S4, as long as it is performed after the correspondence information generation step S3.

[0085] Following the first print data generation step S5, in the first printing step S6, the processing circuit 7b prints the first image G1 indicated by the first image information Dg1 onto the workpiece W. Details of the first printing step S6 will be explained later with reference to Figures 9 and 10.

[0086] After the first printing process S6, in the decision process S7, the processing circuit 7b determines whether or not to perform the next printing on the new workpiece W. This determination is made, for example, by whether or not the user issues a next printing instruction. The decision process S7 is repeated until it is determined that the next printing should be performed (decision process S7: NO). Therefore, for example, until the user issues a next printing instruction, the 3D object printing device 1 remains in a waiting state for printing. It is preferable that this state is maintained even when the power to the 3D object printing device 1 is turned off.

[0087] If the next printing is to be performed (decision step S7: YES), in decision step S8, the processing circuit 7b determines whether or not to change the movement trajectory RU. This determination is made based, for example, on whether or not the shape of the workpiece W has been changed, or whether or not there is a change instruction from the user. Typically, in decision step S8, if the shape of the workpiece W has been changed, the processing circuit 7b decides to change the movement trajectory RU. On the other hand, in decision step S8, if the shape of the workpiece W has not been changed, the processing circuit 7b decides not to change the movement trajectory RU.

[0088] If the movement trajectory RU is changed (decision step S8: YES), the processing circuit 7b returns to the trajectory information generation step S2. Therefore, the processing from the trajectory information generation step S2 to the decision step S7 described above is executed again. However, in the repeated trajectory information generation step S2, the work information Dw is changed to information about the workpiece W whose shape has been changed, and instead of the first image information Dg1, a third image information showing a third image is used to generate trajectory information Da based on the third image information, head information Db, work information Dw, and set values. The third image may be the same as or different from the first image G1. Also, the set values ​​used to generate the trajectory information Da may be changed as necessary.

[0089] If the movement trajectory RU is not changed (decision step S8: NO), in decision step S9, the processing circuit 7b decides whether or not to change the image to be printed from the first image G1 to the second image G2. This decision is made based, for example, on whether or not there is a change instruction from the user.

[0090] If the image is not changed (decision step S9: NO), the processing circuit 7b returns to the first printing step S6. Therefore, the first image G1 is printed again.

[0091] If the image is to be changed (decision step S9: YES), in the second image information acquisition step S10, the processing circuit 7b acquires the second image information Dg2. This acquisition is performed, for example, by the processing circuit 7b reading the second image information Dg2 from the memory circuit 7a or the like. In addition to acquiring the second image information Dg2, setting values ​​are also acquired in the second image information acquisition step S10. These setting values ​​include, for example, the setting value of the distance PG between the head 3a and the workpiece W, the setting value of the overlapping area such as the first overlapping area OV1a described later, and the setting value of the mask pattern. These setting values ​​are acquired, for example, in response to input from the user. Here, the second image information acquisition step S10 includes an instruction acquisition step S12 related to the user's instructions. The instruction acquisition step S12 acquires these setting values. These setting values ​​may be acquired in response to input from the user, or they may be acquired automatically based on the execution of a predetermined program or the like. Furthermore, this setting includes a user-specified tolerance range for the difference between the distance PG corresponding to the main dot (described later) and the distance PG of each sub-dot. This setting may also include information about the type of the second image G2, such as line drawings or photographs.

[0092] Following the second image information acquisition step S10, in the corresponding information acquisition step S11, the processing circuit 7b acquires the corresponding information Dc. This acquisition is performed by the processing circuit 7b reading the corresponding information Dc from the memory circuit 7a. The corresponding information acquisition step S11 may be performed before the second image information acquisition step S10, or it may be performed in parallel with the second image information acquisition step S10.

[0093] Following the correspondence information acquisition step S11, in the overlapping area adjustment step S13, the processing circuit 7b adjusts the size of the overlapping area, such as the first overlapping area OV1a described later. This adjustment is performed, for example, based on instruction information Dd, so that the distance PG between the nozzle N of the head 3a and the workpiece W is made as small as possible, and the angle θ between the liquid discharge direction DE from the nozzle N of the head 3a and the workpiece W is made as close to 90° as possible.

[0094] After the overlapping area adjustment step S13, in the second print data generation step S14, the processing circuit 7b generates print data Img2 based on the correspondence information Dc and the second image information Dg2. The generated print data Img2 is stored in the storage circuit 7a. Details of the second print data generation step S14 will be explained later with reference to Figures 11 to 13. Note that the overlapping area adjustment step S13 may be included in the second print data generation step S14.

[0095] Following the second print data generation step S14, in the second printing step S15, the processing circuit 7b prints the second image G2 indicated by the second image information Dg2 onto the workpiece W. Details of the second printing step S15 will be explained later with reference to Figures 11 to 13.

[0096] After the second printing process S15, in the decision process S16, the processing circuit 7b determines whether or not to terminate. This decision is made based, for example, on whether or not there is a termination instruction from the user.

[0097] If the process does not terminate (decision step S16: NO), the processing circuit 7b returns to the decision step S7. As a result, the 3D object printing device 1 enters a waiting state for printing until the next printing instruction is given by the user. On the other hand, if the process terminates (decision step S16: YES), the processing circuit 7b terminates the process.

[0098] 1-5. Generation of a Moving Trajectory Figure 5 is an explanatory diagram for the generation of the moving trajectory RU. In Figure 5, the workpiece W in the virtual space VS is shown. In the virtual space VS, a coordinate system is set up with the x, y, and z axes intersecting each other. Here, the x axis corresponds to the X axis, with one direction along the x axis being the x1 direction and the opposite direction being the x2 direction. The y axis corresponds to the Y axis, with opposite directions along the y axis being the y1 and y2 directions. The z axis corresponds to the Z axis, with opposite directions along the z axis being the z1 and z2 directions. Note that the x, y, and z axes are typically orthogonal to each other, but are not limited to this; they can intersect at angles within the range of 80° to 100°.

[0099] In the trajectory information generation process S2, first, as shown in Figure 5, the workpiece W is placed in the virtual space VS based on the workpiece information Dw, and the printing area RP is set based on the first image information Dg1, after which multiple reference paths LM are set. As a method for setting multiple reference paths LM, the contents of U.S. Patent Application Publication No. 2024 / 0269855, published on August 15, 2024 (method for setting multiple candidate paths) are incorporated here by reference.

[0100] Multiple reference paths LM are arranged at intervals along the sub-scanning direction DS, which intersects the main scanning direction DM. The main scanning direction DM is the direction along any one of the multiple reference paths LM. Here, in the virtual space VS, multiple reference points PM are set on the sub-scanning reference line LS along the sub-scanning direction DS on the workpiece W, and multiple reference paths LM are set for each reference point PM. Each of the multiple reference paths LM passes through its corresponding reference point PM and intersects the sub-scanning reference line LS.

[0101] In the trajectory information generation step S2, after multiple reference path LMs are set as described above, a movement trajectory RU suitable for executing a printing operation on the printing area RP is generated using at least one of the multiple reference path LMs. In this embodiment, after three reference path LMs are selected from the multiple reference path LMs, a movement trajectory RU including a first printing trajectory RU-1, a second printing trajectory RU-2, a third printing trajectory RU-3, and a fourth printing trajectory RU-4 is generated using these three reference path LMs.

[0102] More specifically, in the trajectory information generation step S2 of this embodiment, three reference path LMs are selected from among multiple reference path LMs as the minimum number of reference path LMs that can cover the entire printing area RP. Then, for the central reference path LM of these three, the reference path LM is divided into two paths of appropriate length, and then a path for the head 3a to run up and a path for the energy emission unit 3c to pre-cure the ink are added to both ends of each divided path, thereby generating the first printing trajectory RU-1 and the third printing trajectory RU-3. Furthermore, for the reference path LM adjacent to one of the central reference path LMs of these three, a path for the head 3a to run up and a path for the energy emission unit 3c to pre-cure the ink are added to both ends of the reference path LM, thereby generating the second printing trajectory RU-2. Furthermore, for the reference path LM adjacent to the central reference path LM among the three reference paths LM, a path for the head 3a to gain momentum and a path for the preliminary curing of the ink by the energy emission unit 3c are added to both ends of the reference path LM, thereby generating a fourth printing path RU-4.

[0103] Furthermore, one or both of the second print track RU-2 and the fourth print track RU-4 may be print tracks divided in the main scanning direction DM, similar to the first print track RU-1 and the third print track RU-3, by dividing the reference path LM into two paths of appropriate length, and then adding paths for the head 3a's run-up and paths for the ink's pre-curing by the energy emission unit 3c to both ends of each divided path. Also, the first print track RU-1 and the third print track RU-3 may be print tracks that are not divided in the main scanning direction DM, similar to the second print track RU-2 or the fourth print track RU-4. In addition, at least one of the second print track RU-2, the third print track RU-3, and the fourth print track RU-4 may be generated as needed and may be omitted. In addition to the first print track RU-1, the second print track RU-2, the third print track RU-3, and the fourth print track RU-4, other print tracks may be generated.

[0104] Furthermore, when generating the first printing trajectory RU-1, the second printing trajectory RU-2, the third printing trajectory RU-3, and the fourth printing trajectory RU-4, the presence or absence of collision between the head 3a and the workpiece W in each trajectory is determined by simulation based on the set value of the distance PG between the head 3a and the workpiece W and the information indicated by the head information Db, and each trajectory is corrected as appropriate based on the determination result.

[0105] Furthermore, the method for generating the first, second, third, and fourth printed paths RU-1, RU-2, RU-3, and RU-4 paths is incorporated here by reference to the content of U.S. Patent Application Publication No. 2024 / 0269855, published on August 15, 2024 (method for setting multiple candidate paths).

[0106] 1-6. Generation of correspondence information Figure 6 is an explanatory diagram of the generation of correspondence information Dc. The first image G1 indicated by the first image information Dg1 is divided into print paths (paths) for each of the aforementioned first print paths RU-1, second print path RU-2, third print path RU-3, and fourth print path RU-4, and printed on the workpiece W. Therefore, in order to generate print data Img1, it is necessary to identify the correspondence between each nozzle N of the head 3a in the moving path RU and the pixels Px of the first image G1 indicated by the first image information Dg1 for each of the print paths for the first print paths RU-1, second print path RU-2, third print path RU-3, and fourth print path RU-4, as shown in Figure 6. In the correspondence information generation process S3, correspondence information Dc related to such correspondences is generated as intermediate data.

[0107] More specifically, in the corresponding information generation process S3, after the first image G1 indicated by the first image information Dg1 is attached to the printing area RP, for each printing trajectory of the first printing trajectory RU-1, the second printing trajectory RU-2, the third printing trajectory RU-3, and the fourth printing trajectory RU-4, the intersection point between the printing area RP and the virtual line extending in the ejection direction DE from each nozzle N of the head 3a indicated by the head information Db is determined, and the pixel Px corresponding to that intersection point is identified.

[0108] In the corresponding information generation process S3, when printing the first image G1 such that the areas printed on the workpiece W by ink ejected from adjacent heads 3a do not overlap, pixels Px corresponding to dots made by ink placed on the workpiece W by the heads 3a are defined as "main dots". Main dots are determined, for example, by considering each dot placed on the workpiece W by the heads 3a of each trajectory as a particle and performing mutual exclusion processing between dots within the influence radius. This mutual exclusion search starts from the central nozzle N with the best conditions among the multiple nozzles N of the head 3a and is performed for all dots in all passes. Note that the dot mutual exclusion processing is not limited to processing using particles, but may also be done using, for example, voxel processing. Furthermore, the contents of U.S. Patent Application Publication No. 2024 / 0269855, published on August 15, 2024 (method for setting multiple candidate paths), are incorporated here by reference regarding the dot mutual exclusion processing.

[0109] When printing using only the main dots, errors in the movement of the robot 2 and errors in ink placement from nozzle N onto the workpiece W can easily cause a decrease in image quality, known as white or black streaks, between areas printed on the workpiece W by ink ejected from adjacent heads 3a. One printing method that suppresses this decrease in image quality is printing using POL (partial overlap) processing, which overlaps parts of the areas printed on the workpiece W by ink ejected from adjacent heads 3a.

[0110] Therefore, in the corresponding information generation process S3, when printing the first image G1 by POL processing between the first printing track RU-1 or the third printing track RU-3 and the second and fourth printing tracks RU-2 and RU-4, pixels Px corresponding to dots that are placed in place of the main dots in the area being processed by POL are defined as "subdots".

[0111] Furthermore, in the corresponding information generation process S3, when the first image G1 is printed by POL processing by dividing the path into the main scanning direction DM, such as the first printing path RU-1 and the third printing path RU-3, the dots that are placed in place of the main dots in the POL processed area in the main scanning direction DM are defined as "main scanning POL subdots". Main scanning POL subdots are, for example, dots placed in the path divided by the main scanning direction DM of existing main dots and subdots, and are neither main dots nor subdots of other dots.

[0112] Furthermore, in the correspondence information generation process S3, the correspondence between each nozzle N of the head 3a in the moving trajectory RU and the pixels Px of the first image G1 is determined, as well as the distance PG between each nozzle N and the printing area RP, the angle θ between the liquid discharge direction from each nozzle N and the printing area RP, the distance between the nozzle N and the center of the head 3a, and the distance between the nozzle N and the edge of the printing area RP in the main scanning direction DM. This information is included in the correspondence information Dc. Details of the correspondence information Dc will be explained later with reference to Figure 8.

[0113] Figure 7 is an explanatory diagram of the moving trajectory RU and the printing area RP. In Figure 7, the maximum printing area RP during a printing operation using the first printing trajectory RU-1, the second printing trajectory RU-2, the third printing trajectory RU-3, and the fourth printing trajectory RU-4 is shown unfolded in a plane for easier understanding.

[0114] When performing a printing operation in which the head 3a moves along the first printing trajectory RU-1, ink is applied to the first area RP1 on the workpiece W. That is, the first area RP1 is the area printed by the liquid ejected from the head 3a moving along the first printing trajectory RU-1. When performing a printing operation in which the head 3a moves along the second printing trajectory RU-2, ink is applied to the second area RP2 on the workpiece W. That is, the second area RP2 is the area printed by the liquid ejected from the head 3a moving along the second printing trajectory RU-2. When performing a printing operation in which the head 3a moves along the third printing trajectory RU-3, ink is applied to the third area RP3 on the workpiece W. That is, the third area RP3 is the area printed by the liquid ejected from the head 3a moving along the third printing trajectory RU-3. When performing a printing operation in which the head 3a moves along the fourth printing trajectory RU-4, ink is applied to the fourth area RP4 on the workpiece W. In other words, the fourth region RP4 is the region printed by the liquid ejected from the head 3a as it moves along the fourth printing track RU-4.

[0115] Here, the first printing trajectory RU-1 is the trajectory that moves the head 3a from position PS1 to position PE1. The second printing trajectory RU-2 is the trajectory that moves the head 3a from position PS2 to position PE2 and is adjacent to the first printing trajectory RU-1 in the sub-scanning direction DS. The third printing trajectory RU-3 is the trajectory that moves the head 3a from position PS3 to position PE3 and is adjacent to the first printing trajectory RU-1 in the main scanning direction DM. The fourth printing trajectory RU-4 is the trajectory that moves the head 3a from position PS4 to position PE4 and is adjacent to the first printing trajectory RU-1 in the sub-scanning direction DS on the opposite side from the second printing trajectory RU-2.

[0116] The second region RP2 overlaps with the first region RP1 in the first overlapping region OV1a, and overlaps with the third region RP3 in the third overlapping region OV3a. The first overlapping region OV1a is the region where the first region RP1 and the second region RP2 overlap, and is printable by the subdots of the head 3a moving along the first print trajectory RU-1 and the second print trajectory RU-2. The third overlapping region OV3a is the region where the second region RP2 and the third region RP3 overlap, and is printable by the subdots of the head 3a moving along the second print trajectory RU-2 and the third print trajectory RU-3.

[0117] The first region RP1 and the third region RP3 overlap in the second overlapping region OV2. The second overlapping region OV2 is the region where the first region RP1 and the third region RP3 overlap, and is printable by the main scanning POL subdot of the head 3a moving along the first print trajectory RU-1 and the third print trajectory RU-3.

[0118] The fourth region RP4 overlaps with the first region RP1 in the fourth overlapping region OV1b, and also overlaps with the third region RP3 in the fifth overlapping region OV3b. The fourth overlapping region OV1b is the region where the first region RP1 and the fourth region RP4 overlap, and is printable by the subdots of the head 3a moving along the first print trajectory RU-1 and the fourth print trajectory RU-4. The fifth overlapping region OV3b is the region where the third region RP3 and the fourth region RP4 overlap, and is printable by the subdots of the head 3a moving along the fourth print trajectory RU-4 and the third print trajectory RU-3. In the following, the first overlapping region OV1a, the second overlapping region OV2, the third overlapping region OV3a, the fourth overlapping region OV1b, and the fifth overlapping region OV3b may all be referred to simply as overlapping region OV without distinction.

[0119] In the first print data generation process S5, print data Img1 is generated based on the correspondence information Dc and the first image information Dg1.

[0120] To explain in more detail, in the first print data generation process S5, sub-dots whose difference between the distance PG corresponding to the main dot and the distance PG corresponding to each sub-dot is outside the user-specified tolerance range are excluded. This limits the width of each overlapping region OV, such as the aforementioned first overlapping region OV1a, in order to restrict the use of dots that are likely to cause a decrease in print quality. This tolerance range is acquired as a set value in the aforementioned first image information acquisition process S1. Therefore, the width of each overlapping region OV is adjusted based on this set value.

[0121] Furthermore, in the first print data generation process S5, when POL processing is performed, it is determined whether to use subdots or main dots for each nozzle N, according to the following conditions.

[0122] First, for each dot, the POL occurrence rate in the sub-scanning direction DS and the POL occurrence rate in the main scanning direction DM are calculated. The POL occurrence rate is used to identify subdots. For example, the POL occurrence rate is expressed as a percentage.

[0123] The POL generation rate in the sub-scanning direction DS is calculated based on the distance between the nozzle N and the center of the nozzle surface FN, and increases as this distance increases. Specifically, the POL generation rate for dots ejected from nozzle N located at the center of the nozzle surface FN is set to 0%, and the POL generation rate for dots ejected from nozzle N located at the edge of the nozzle surface FN in the sub-scanning direction DS is set to 100%.

[0124] The rate of POL occurrence in the main scanning direction DM increases towards the edges in the main scanning direction DM. Specifically, the rate of POL occurrence in the main scanning direction DM is set in a region from the edge to the center of the first region RP1 in the main scanning direction DM, for example, up to a certain length, for example, 5 mm, and is set so that the rate of POL occurrence at the dots on one end side of the first region RP1 is 100%, and the rate of POL occurrence at the dots on the other end side of the same region is 0%.

[0125] A table is created for each dot that takes into account the occurrence rate of these POLs. Based on the comparison between the values ​​in this table and the mask values ​​of the POL mask, dots corresponding to values ​​exceeding the mask values ​​are determined to be subdots instead of main dots. In the following, POLs in the sub-scanning direction DS may be referred to as sub-scanning POLs. Similarly, POLs in the main scanning direction DM may be referred to as main scanning POLs.

[0126] Based on the above results, the information indicating where dots should be placed is compiled for each pass, and the print data Img1 is created. This reduces the proportion of dots in the overlapping area OV, enabling smooth gradation changes.

[0127] Figure 8 shows an example of correspondence information Dc. Figure 8 shows an example of correspondence information Dc when POL processing is performed in both the main scanning direction DM and the sub-scanning direction DS.

[0128] As shown in Figure 8, the correspondence information Dc includes pixel information Dc1a, distance information Dc2a, angle information Dc3a, occurrence rate information Dc4a, first overlapping pixel information Dc1b, first distance information Dc2b, first angle information Dc3b, first occurrence rate information Dc4b, second overlapping pixel information Dc1c, second distance information Dc2c, second angle information Dc3c, and second occurrence rate information Dc4c.

[0129] Here, pixel information Dc1a, distance information Dc2a, angle information Dc3a, and occurrence rate information Dc4a are information about the main dot. The first overlapping pixel information Dc1b, first distance information Dc2b, first angle information Dc3b, and first occurrence rate information Dc4b are information about the subdots of the overlapping region OV in the sub-scanning direction DS. The second overlapping pixel information Dc1c, second distance information Dc2c, second angle information Dc3c, and second occurrence rate information Dc4c are information about the subdots of the overlapping region OV in the main scanning direction DM, i.e., information about the main scanning POL subdots. Note that either or both of the information about the subdots of the overlapping region OV in the sub-scanning direction DS and the information about the subdots of the overlapping region OV in the main scanning direction DM may be included in the corresponding information Dc as needed, or may be omitted.

[0130] Pixel information Dc1a is information that shows the correspondence between the nozzle N of the head 3a in the moving trajectory RU and the pixel Px in the printing area RP of the workpiece W. Pixel information Dc1a is information that shows the correspondence between the nozzle N of the head 3a in the moving trajectory RU and the pixel Px in the printing area RP of the workpiece W. In the example shown in Figure 8, pixel information Dc1a includes information indicating the "path number for dotting", the "nozzle number for dotting", the "shot number for dotting", the "image reference position (x coordinate)", and the "image reference position (y coordinate)". The image reference position (x coordinate) is the normalized x coordinate value of the pixel Px of the first image G1 in a two-dimensional xy coordinate system. The image reference position (y coordinate) is the normalized y coordinate value of the pixel Px of the first image G1 in a two-dimensional xy coordinate system.

[0131] Distance information Dc2a is information about the distance PG between the nozzle N of the head 3a and the printing area RP in the moving trajectory RU. Here, distance information Dc2a is associated with a set of "path number to print the dot", "nozzle number to print the dot", and "shot number to print the dot".

[0132] The angle information Dc3a is information about the angle θ between the direction of liquid discharge from the nozzle N of the head 3a and the printing area RP. Here, the angle information Dc3a is associated with a set of "path number for dotting", "nozzle number for dotting", and "shot number for dotting".

[0133] The occurrence rate information Dc4a is information regarding the occurrence rate of the aforementioned dots for the main dot. In the example shown in Figure 8, the occurrence rate information Dc4a includes information indicating the "occurrence rate of main scan POLs" and the "occurrence rate of sub-scan POLs".

[0134] The first overlapping pixel information Dc1b is information indicating the correspondence between the pixels Px of each overlapping region OV in the first overlapping region OV1a, the third overlapping region OV3a, the fourth overlapping region OV1b, and the fifth overlapping region OV3b, and the nozzle N of the head 3a. In the example shown in Figure 8, the first overlapping pixel information Dc1b, like the pixel information Dc1a, includes information indicating the "path number for dotting," the "nozzle number for dotting," the "shot number for dotting," the "image reference position (x coordinate)," and the "image reference position (y coordinate)."

[0135] The first distance information Dc2b is information regarding the distance PG between the nozzle N of head 3a and each of the overlapping regions OV of the first overlapping region OV1a, the third overlapping region OV3a, the fourth overlapping region OV1b, and the fifth overlapping region OV3b. Here, the first distance information Dc2b is associated with a set of "path number to dock", "nozzle number to dock", and "shot number to dock".

[0136] The first angle information Dc3b is information regarding the angle θ between the liquid discharge direction DE from the nozzle N of the head 3a and each of the overlapping regions OV of the first overlapping region OV1a, the third overlapping region OV3a, the fourth overlapping region OV1b, and the fifth overlapping region OV3b. Here, the first angle information Dc3b is associated with a set of "path number to dot", "nozzle number to dot", and "shot number to dot".

[0137] The first occurrence rate information Dc4b is information regarding the occurrence rate of the aforementioned dots for each subdot. In the example shown in Figure 8, the first occurrence rate information Dc4b includes information indicating the "occurrence rate of main scan POLs" and the "occurrence rate of sub-scan POLs".

[0138] The second overlapping pixel information Dc1c is information indicating the correspondence between pixels in the second overlapping region OV2 and nozzle N of head 3a. In the example shown in Figure 8, the second overlapping pixel information Dc1c, like the pixel information Dc1a, includes information indicating the "path number for dotting," the "nozzle number for dotting," the "shot number for dotting," the "image reference position (x coordinate)," and the "image reference position (y coordinate)."

[0139] The second distance information Dc2c is information about the distance PG between the nozzle N of head 3a and the second overlapping region OV2. Here, the second distance information Dc2c is associated with a set of "path number to dot", "nozzle number to dot", and "shot number to dot".

[0140] The second angle information Dc3c is information about the angle θ between the liquid discharge direction DE from the nozzle N of head 3a and the second overlapping region OV2. Here, the second angle information Dc3c is associated with a set of "path number to dot", "nozzle number to dot", and "shot number to dot".

[0141] The second occurrence rate information Dc4c is information regarding the occurrence rate of the aforementioned dots for the main scan POL subdot. In the example shown in Figure 8, the second occurrence rate information Dc4c includes information indicating the "occurrence rate of main scan POL" and the "occurrence rate of subscan POL".

[0142] The correspondence information Dc described above is stored in the storage circuit 7a in the storage step S4. By using the correspondence relationship indicated by the correspondence information Dc, print data Img can be generated even if the image to be printed is changed. Therefore, in the second print data generation step S14, by using the correspondence relationship indicated by the correspondence information Dc, print data Img2 for printing the second image G2 indicated by the second image information Dg2 is generated without regenerating the trajectory information Da. This reduces the time required to generate print data Img2 compared to the method in which the trajectory information Da is regenerated.

[0143] Furthermore, when performing multi-color printing, it is possible to generate print data for each color for multi-color printing by applying the halftone data of each color, such as CMYK, to the correspondence relationship indicated in the correspondence information Dc.

[0144] Furthermore, when performing POL processing, the dot pattern in the overlapping area OV can be changed by modifying the POL mask. When performing multi-color printing, by using different POL masks for creating the print data for each color, it is possible to generate print data Img2 with reduced printing unevenness.

[0145] Furthermore, since the correspondence information Dc includes information about the distance PG and angle θ, it is possible to suppress image quality degradation by adjusting the size (width) of the overlapping region OV depending on the type of image, etc.

[0146] 1-7. Print data for the first image and the first printing process Figure 9 is an explanatory diagram of print data Img1 for printing the first image G1. Figure 10 is an explanatory diagram of another example of print data Img1 for printing the first image G1. Figures 9 and 10 show the first region RP1 and the third region RP3 of the first image G1. For the sake of explanation, in Figures 9 and 10, the first region RP1 and the third region RP3 of the first image G1 are shown with a gap between them.

[0147] In the first printing process S6, the first image G1 is printed based on the print data Img1. When the first image G1 is printed without POL processing, as shown in Figure 9, image G1a, which corresponds to the first region RP1 of the first image G1, and image G1b, which corresponds to the third region RP3, are printed. Images G1a and G1b are images composed only of main dots. That is, images G1a and G1b are images that do not have overlapping regions OV.

[0148] Furthermore, when the first image G1 is printed after POL processing, as shown in Figure 10, image G1c corresponding to the first region RP1 of the first image G1 and image G1d corresponding to the third region RP3 are printed. Images G1c and G1d are composed of main dots, subdots, and main scan POL subdots. In other words, images G1c and G1d are images that have an overlapping region OV.

[0149] 1-8. Print data for the second image and the second printing process Figure 11 is an explanatory diagram of print data Img2 for printing the second image G2. Figure 12 is an explanatory diagram of another example of print data Img2 for printing the second image G2. Figure 13 is an explanatory diagram of print data Img2 for multicolor printing. Figures 11 and 12 show the first region RP1 and the third region RP3 of the second image G2. Figure 13 shows the third region RP3 of the second image G2. For the sake of explanation, in Figures 11 and 12, the first region RP1 and the third region RP3 of the second image G2 are shown with a gap between them.

[0150] The second print data generation step S14 generates print data Img2 based on the correspondence information Dc and the second image information Dg2. In this way, the correspondence information Dc, which is generated as intermediate data when generating the print data Img1 of the first image G1, is used to generate the print data Img2 of the second image G2. As a result, it is no longer necessary to create a movement trajectory RU for each image, and the time required to create the movement trajectory RU can be reduced.

[0151] Here, by using pixel information Dc1a, the corresponding information Dc can be used to generate the print data Img2 of the second image G2. Furthermore, by using distance information Dc2a, even if the distance PG between each nozzle N of the head 3a and the workpiece W varies greatly depending on the shape of the workpiece W, the print quality can be improved by adjusting the nozzle N used for ejection based on the distance information Dc2a.

[0152] In the second printing process S15, the second image G2 is printed based on the print data Img2. When the second image G2 is printed without POL processing, as shown in Figure 11, image G2a, which corresponds to the first region RP1 of the second image G2, and image G2b, which corresponds to the third region RP3, are printed. Images G2a and G2b are composed only of main dots. That is, images G2a and G2b are images that do not have an overlapping region OV.

[0153] Thus, the second printing process S15 prints a second image G2 that is different from the first image G1. In both the first printing process S6 and the second printing process S15, the robot 2 moves the head 3a along the movement path RU. In this way, even when printing on a new workpiece W, if the shape of the workpiece W does not change, the movement path RU of the head 3a is shared between printing the first image G1 and the second image G2, eliminating the need to create a separate movement path RU for each image, and consequently reducing the time required to create the movement path RU.

[0154] Furthermore, when POL processing is performed to print the second image G2, as shown in Figure 12, image G2c, which corresponds to the first region RP1 of the second image G2, and image G2d, which corresponds to the third region RP3, are printed. Images G2c and G2d are composed of main dots, subdots, and main scan POL subdots. In other words, images G2c and G2d are images that have an overlapping region OV.

[0155] In the second print data generation step S14, based on the correspondence relationship indicated by the first overlapping pixel information Dc1b and the setting value information indicated by the instruction information Dd, the width of each overlapping area OV of the first overlapping area OV1a, third overlapping area OV3a, fourth overlapping area OV1b, and fifth overlapping area OV3b, or the amount of liquid discharged to the overlapping area OV, can be changed according to the type of image to be printed or the instruction by the user. As a result, the print quality of the overlapping area OV can be improved or the print quality of the overlapping area OV can be adjusted according to the user's wishes. For example, if the setting value information includes information about the type of image, such as a line drawing or a photograph, the width of the overlapping area OV can be reduced in the case of a line drawing, and the width of the overlapping area OV can be increased in the case of a photograph.

[0156] Furthermore, by using the first distance information Dc2b, even if the distance PG between each nozzle N of the head 3a and the workpiece W varies greatly depending on the shape of the workpiece W, the print quality can be improved by adjusting the nozzle N used for ejection based on the first distance information Dc2b and the setting value and other information indicated by the instruction information Dd.

[0157] Furthermore, based on the correspondence indicated by the second overlapping pixel information Dc1c and the setting values ​​indicated by the instruction information Dd, the width of the second overlapping region OV2 or the amount of liquid discharged to the second overlapping region OV2 can be changed according to the type of image to be printed or the user's instructions. As a result, the print quality of the second overlapping region OV2 can be improved or adjusted according to the user's wishes.

[0158] In this embodiment, in the overlapping area adjustment step S13, the sizes of the first overlapping area OV1a, the third overlapping area OV3a, the fourth overlapping area OV1b, and the fifth overlapping area OV3b are adjusted. By adjusting the size of these overlapping areas OV for each image, the print quality of the overlapping areas OV can be adjusted according to the user's wishes.

[0159] Furthermore, in the overlapping area adjustment process S13, the sizes of the first overlapping area OV1a, the third overlapping area OV3a, the fourth overlapping area OV1b, and the fifth overlapping area OV3b are adjusted based on the first distance information Dc2b. This reduces the use of nozzles N with large distances PG to these overlapping areas OV, thereby improving the print quality of these overlapping areas OV.

[0160] Furthermore, in the overlapping area adjustment step S13, the sizes of the first overlapping area OV1a, the third overlapping area OV3a, the fourth overlapping area OV1b, and the fifth overlapping area OV3b are adjusted based on the first angle information Dc3b. This reduces the use of nozzles N where the angle θ between the ejection direction DE and these overlapping areas OV is greater than 90°, thereby improving the print quality of these overlapping areas OV. More specifically, for each nozzle N, it is determined whether the angle θ exceeds a threshold, the use of nozzles N where the angle θ exceeds the threshold is restricted, and the width of the overlapping areas OV is narrowed so that the overlapping areas OV are printed with dots from nozzles N where the angle θ is below the threshold, thereby improving the print quality of the overlapping areas OV.

[0161] Furthermore, in the overlapping area adjustment process S13, the sizes of the first overlapping area OV1a, the third overlapping area OV3a, the fourth overlapping area OV1b, and the fifth overlapping area OV3b are adjusted based on the instruction information Dd. This allows the print quality of these overlapping areas OV to be adjusted according to the user's wishes.

[0162] Furthermore, when printing the second image G2 in multiple colors, as shown in Figure 13, images G2-C, G2-M, G2-Y, and G2-K, based on the print data Img2 for each color, are sequentially superimposed and printed to produce a multi-colored second image G2. In the example shown in Figure 13, image G2-C is a cyan image, image G2-M is a magenta image, image G2-Y is a yellow image, and image G2-K is a black image. The print data Img2 for images G2-C, G2-M, G2-Y, and G2-K are generated using different POL masks so that their dots do not overlap. Note that the colors and number of colors used in multi-color printing are not limited to cyan, magenta, yellow, and black, but are arbitrary.

[0163] Thus, in the second print data generation step S14, print data Img2 is generated for each liquid color based on the corresponding information Dc. This reduces the time required to generate all color print data Img2 when performing color printing, compared to a method in which print data is created for each color based on the trajectory information Da and the second image information Dg2.

[0164] Here, as mentioned above, in the second print data generation step S14, the print data Img2 is generated by changing the mask pattern for each liquid color. That is, the control method includes a step of generating print data Img2 by changing the mask pattern for each liquid color in each of the first overlapping region OV1a, third overlapping region OV3a, fourth overlapping region OV1b, and fifth overlapping region OV3b. This makes it possible to reduce the overlap of dots of different colors in these overlapping regions OV. As a result, unevenness in these overlapping regions OV can be reduced.

[0165] However, the same mask pattern is used for printing images of the same color across passes. For example, the mask pattern used for the first region RP1 and the mask pattern used for the second region RP2 are the same. This reduces unevenness in the overlapping region OV.

[0166] 2. Variations Each of the above examples can be modified in various ways. Specific examples of modifications that can be applied to each of the aforementioned examples are given below. Two or more of the following examples can be arbitrarily selected and combined as appropriate, provided they do not contradict each other.

[0167] 2-1. Variation 1 In the above-described configuration, an example is given in which the process from the first image information acquisition step S1 to the decision step S16 is executed as a series of steps. However, the configuration is not limited to this configuration, and for example, the corresponding information Dc may be stored in the memory circuit 7a in advance. In this case, if the same movement trajectory RU is used as the movement trajectory RU used when the corresponding information Dc was created, the print data Img is generated using the corresponding information Dc. In this case, for example, the process from the second image information acquisition step S10 to the decision step S16 shown in Figure 2 is performed.

[0168] Furthermore, correspondence information Dc may be generated for each workpiece with a different shape and stored in the memory circuit 7a. For example, when a workpiece is changed to one with a different shape, the correspondence information Dc for that workpiece may be obtained from the memory circuit 7a, and print data may be generated using this correspondence information Dc.

[0169] Furthermore, the correspondence information Dc may be obtained from a source other than the memory circuit 7a. For example, the correspondence information Dc may be obtained from an external server connected to the control unit 8.

[0170] 2-2. Variation 2 In the above-described embodiment, an example is given in which a 6-axis vertical multi-axis robot is used as the moving mechanism for moving the head 3a. However, the embodiment is not limited to this, and the moving mechanism may be, for example, a vertical multi-axis robot other than a 6-axis robot, a horizontal multi-axis robot, or a mechanism that combines a linear motion mechanism that moves the head 3a along the X-axis and a linear motion mechanism that moves the head 3a along the Z-axis. Furthermore, the robot's arm may have a telescopic mechanism or a linear motion mechanism in addition to a joint composed of a rotation mechanism.

[0171] 2-3. Variation 3 In the above-described embodiment, a configuration in which screws or the like are used to fix the head 3a to the robot 2 is exemplified, but the embodiment is not limited to this configuration. For example, the head 3a may be fixed to the robot 2 by gripping it with a gripping mechanism such as a hand attached as an end effector to the robot 2.

[0172] 2-4. Variation 4 The applications of the three-dimensional object printing apparatus described herein are not limited to image printing. For example, a three-dimensional object printing apparatus that dispenses a colorant solution can be used as a manufacturing apparatus for forming color filters for liquid crystal display devices. A three-dimensional object printing apparatus that dispenses a conductive material solution can be used as a manufacturing apparatus for forming wiring and electrodes on a wiring board. Furthermore, a three-dimensional object printing apparatus can also be used as a jet dispenser for applying liquids such as adhesives to a medium.

[0173] 3. Addendum From the above forms and variations, the following characteristics can be understood.

[0174] (Note 1) A first embodiment of the control method of the present disclosure is a control method for controlling the operation of a three-dimensional object printing apparatus having a liquid discharge head for discharging liquid toward a workpiece and a moving mechanism for moving the liquid discharge head, the method comprising: a trajectory information generation step of generating trajectory information relating to the movement trajectory of the moving mechanism moving the liquid discharge head; a correspondence information generation step of generating correspondence information that associates the trajectory information with head information relating to the liquid discharge head and first image information relating to a first image to be printed; a storage step of storing the correspondence information; and a print data generation step of generating print data for printing a second image based on the correspondence information and second image information relating to a second image to be printed.

[0175] In the above embodiment, the correspondence information generated as intermediate data when generating the print data for the first image is used to generate the print data for the second image. This eliminates the need to create a movement trajectory for each image, and as a result, the time required to create the movement trajectory can be reduced.

[0176] (Note 2) In a second embodiment, which is a preferred example of the first embodiment, the correspondence information includes pixel information indicating the correspondence between the nozzle of the liquid discharge head in the moving trajectory and the pixels of the print area of ​​the workpiece. In the above embodiments, the correspondence information can be used to generate print data for the second image. Since the nozzle of the liquid discharge head and the pixels of the print area are associated, the correspondence between the pixels of the corresponding print area and the nozzle of the liquid discharge head can be identified when printing the second image.

[0177] (Note 3) In a third embodiment which is a preferred example of the first or second embodiment, the correspondence information includes distance information relating to the distance between the nozzle of the liquid discharge head and the printing area in the moving trajectory. In the above embodiments, even if the distance between each nozzle of the liquid discharge head and the workpiece varies greatly depending on the shape of the workpiece, the print quality can be improved by adjusting the nozzle used for discharge based on the distance information.

[0178] (Note 4) In a fourth embodiment, which is a preferred example of any of the first to third embodiments, the moving trajectory includes a first printing trajectory and a second printing trajectory adjacent to the first printing trajectory in a sub-scanning direction intersecting the main scanning direction along the first printing trajectory, and the correspondence information includes first overlapping pixel information indicating the correspondence between pixels in a first overlapping region where a first region printed by liquid discharged from the liquid discharge head moving along the first printing trajectory and a second region printed by liquid discharged from the liquid discharge head moving along the second printing trajectory overlap, and the nozzles of the liquid discharge head. In the above embodiments, based on the correspondence between pixels in the first overlapping region and the nozzles of the liquid discharge head, the width of the first overlapping region or the amount of liquid discharged to the first overlapping region can be changed according to the type of image to be printed or instructions from the user. As a result, the print quality of the first overlapping region can be improved or the print quality of the first overlapping region can be adjusted according to the user's wishes.

[0179] (Note 5) In a fifth embodiment, which is a preferred example of the fourth embodiment, the moving trajectory further includes a third printing trajectory adjacent to the first printing trajectory in the main scanning direction along the first printing trajectory, and the correspondence information includes second overlapping pixel information indicating the correspondence between pixels in a second overlapping region where the third region printed by the liquid discharged from the liquid discharge head moving along the third printing trajectory overlaps with the second region, and the nozzle of the liquid discharge head. In the above embodiments, based on the correspondence between pixels in the second overlapping region and the nozzle of the liquid discharge head, the width of the second overlapping region or the amount of liquid discharged to the second overlapping region can be changed according to the type of image to be printed or instructions from the user. As a result, the print quality of the second overlapping region can be improved or the print quality of the second overlapping region can be adjusted according to the user's wishes.

[0180] (Note 6) In the fourth embodiment or a sixth embodiment which is a preferred example of either the fourth embodiment, the process further includes an overlapping area adjustment step for adjusting the size of the first overlapping area. In the above embodiments, the print quality of the first overlapping area can be adjusted according to the user's wishes by adjusting the size of the first overlapping area for each image.

[0181] (Note 7) In the seventh embodiment, which is a preferred example of the sixth embodiment, the correspondence information includes first distance information relating to the distance between the nozzle of the liquid discharge head and the first overlapping region, and in the overlapping region adjustment step, the size of the first overlapping region is adjusted based on the first distance information. In the above embodiments, the print quality of the first overlapping region can be improved by reducing the use of nozzles that are farther from the first overlapping region.

[0182] (Note 8) In the eighth embodiment, which is a preferred example of the sixth or seventh embodiment, the correspondence information further includes first angular information relating to the angle between the liquid discharge direction from the nozzle of the liquid discharge head and the first overlapping region, and in the overlapping region adjustment step, the size of the first overlapping region is adjusted based on the first angular information. In the above embodiments, the print quality of the first overlapping region can be improved by reducing the use of nozzles in which the angle between the discharge direction and the first overlapping region is greater than 90°.

[0183] (Note 9) In the ninth embodiment, which is a preferred example of any of the sixth to eighth embodiments, the method further includes an instruction acquisition step of acquiring instruction information relating to user instructions, wherein in the overlapping area adjustment step, the size of the first overlapping area is adjusted based on the instruction information. In the above embodiments, the print quality of the first overlapping area can be adjusted according to the user's wishes.

[0184] (Note 10) In the tenth embodiment, which is a preferred example of any of the fourth to ninth embodiments, the process includes a step of changing the mask pattern for each liquid color in the first overlapping region to generate print data. In the above embodiments, the overlap of dots of different colors in the first overlapping region can be reduced. As a result, unevenness in the first overlapping region can be reduced.

[0185] (Note 11) In the 11th embodiment, which is a preferred example of any of the first to tenth embodiments, in the print data generation step, print data is generated for each liquid color based on the correspondence information. In the above embodiments, when performing color printing, the time required to generate print data for all colors can be shortened compared to the embodiment in which print data is created for each color based on trajectory information and image information for each color.

[0186] (Note 12) In the twelfth embodiment, which is a preferred example of the eleventh embodiment, the print data generation process is performed by changing the mask pattern for each liquid color to generate the print data. In this embodiment, the overlap of dots of different colors can be reduced. As a result, unevenness in the first overlapping region can be reduced.

[0187] (Note 13) In the 13th embodiment, which is a preferred example of the 12th embodiment, the moving trajectory includes a first printing trajectory and a second printing trajectory adjacent to the first printing trajectory in a sub-scanning direction intersecting the main scanning direction along the first printing trajectory, and the correspondence information includes first overlapping pixel information indicating the correspondence between pixels in a first overlapping region where a first region printed by liquid discharged from the liquid discharge head moving along the first printing trajectory and a second region printed by liquid discharged from the liquid discharge head moving along the second printing trajectory overlap, and the mask pattern used for the first region and the mask pattern used for the second region are the same. In the above embodiment, unevenness in the first overlapping region can be reduced.

[0188] (Note 14) A 14th embodiment, which is a preferred example of a three-dimensional object printing apparatus of the present disclosure, comprises a liquid discharge head for discharging liquid toward a workpiece, and a moving mechanism for moving the liquid discharge head, wherein the moving mechanism generates trajectory information relating to the movement trajectory of the liquid discharge head, generates correspondence information relating the trajectory information, head information relating to the liquid discharge head, and first image information relating to a first image to be printed, and generates print data for printing the second image based on the correspondence information and second image information relating to a second image to be printed.

[0189] In the above embodiment, the correspondence information generated as intermediate data when generating the print data for the first image is used to generate the print data for the second image. This eliminates the need to create a movement trajectory for each image, and as a result, the time required to create the movement trajectory can be reduced.

[0190] (Note 15) A 15th aspect, which is another preferred example of a control method of the present disclosure, is a control method for controlling the operation of a three-dimensional object printing apparatus having a liquid discharge head for discharging liquid toward a workpiece and a moving mechanism for moving the liquid discharge head, comprising: a trajectory information generation step of generating trajectory information relating to a moving trajectory by which the moving mechanism moves the liquid discharge head; a first printing step of printing a first image; and a second printing step of printing a second image different from the first image, wherein in both the first printing step and the second printing step, the moving mechanism moves the liquid discharge head along the moving trajectory.

[0191] In the above embodiment, the movement trajectory of the liquid discharge head is shared between printing the first image and printing the second image, eliminating the need to create a separate movement trajectory for each image. As a result, the time required to create the movement trajectory can be reduced.

[0192] (Note 16) A 16th embodiment, which is a preferred example of a three-dimensional object printing apparatus of the present disclosure, comprises a liquid discharge head for discharging liquid toward a workpiece, a moving mechanism for moving the liquid discharge head, a storage unit for storing correspondence information that associates trajectory information relating to the movement trajectory of the movement mechanism for moving the liquid discharge head, head information relating to the liquid discharge head, and first image information relating to a first image to be printed, and generates print data for printing the second image based on the correspondence information and second image information relating to a second image to be printed.

[0193] In the above embodiment, the correspondence information generated as intermediate data when generating the print data for the first image is used to generate the print data for the second image. This eliminates the need to create a movement trajectory for each image, and as a result, the time required to create the movement trajectory can be reduced. [Explanation of symbols]

[0194] 1...3D object printing device, 2...Robot, 2a...Arm drive mechanism, 3...Head unit, 3a...Head, 3c...Energy emitter, 3e...Switch circuit, 3f...Support, 5...Controller, 5a...Memory circuit, 5b...Processing circuit, 6...Control module, 6a...Timing signal generation circuit, 6b...Power supply circuit, 6c...Control circuit, 6d...Drive signal generation circuit, 7...Computer, 7a...Memory circuit, 7b...Processing circuit, 8...Control unit, 210...Base, 220...Arm, 221...Arm, 222...Arm, 223...Arm, 224...Arm, 225...Arm, 226...Arm, 230 ...joint, 230_1...joint, 230_2...joint, 230_3...joint, 230_4...joint, 230_5...joint, 230_6...joint, CLK...clock signal, CNG...change signal, Com...drive signal, D1...output, D3...signal, DE...discharge direction, DM...main scanning direction, DN...nozzle row direction, DS...sub-scanning direction, Da...trajectory information, Db...head information, Dc...correspondence information, Dc1a...pixel information, Dc1b...first overlapping pixel information, Dc1c...second overlapping pixel information, Dc2a...distance information, Dc2b...first distance information, Dc2c...second distance information, Dc3a...angle information, Dc3b...second 1. Angle information, Dc3c...2nd angle information, Dc4a...Occurrence rate information, Dc4b...1st occurrence rate information, Dc4c...2nd occurrence rate information, Dd...Instruction information, Dg1...1st image information, Dg2...2nd image information, Dw...Work information, FN...Nozzle surface, G1...1st image, G1a...Image, G1b...Image, G1c...Image, G1d...Image, G2...2nd image, G2-C...Image, G2-K...Image, G2-M...Image, G2-Y...Image, G2a...Image, G2b...Image, G2c...Image, G2d...Image, Img...Print data, Img1...Print data, Img2...Print data, LAT...Latch signal LM...Reference path, LS...Sub-scan reference line, N...Nozzle, NL...Nozzle row, NL1...First nozzle row, NL2...Second nozzle row, O1...Rotation axis, O2...Rotation axis, O3...Rotation axis, O4...Rotation axis, O5...Rotation axis, O6...Rotation axis, OV...Overlap region, OV1a...First overlap region, OV1b...Fourth overlap region, OV2...Second overlap region, OV3a...Third overlap region, OV3b...Fifth overlap region, PD...Drive pulse, PE1...Position, PE2...Position, PE3...Position, PE4...Position, PG...Distance, PM...Reference point, PR...Program, PS1...Position, PS2...Position, PS3...Position, PS4...Position,PTS...timing signal, Px...pixel, RP...printing area, RP1...first area, RP2...second area, RP3...third area, RP4...fourth area, RU...movement trajectory, RU-1...first printing trajectory, RU-2...second printing trajectory, RU- 3...Third printing trajectory, RU-4...Fourth printing trajectory, S1...First image information acquisition process, S2...Trajectory information generation process, S3...Corresponding information generation process, S4...Storage process, S5...First print data generation process, S6...First printing process, S7...Judgment process S8...Decision process, S9...Decision process, S10...Second image information acquisition process, S11...Correspondence information acquisition process, S12...Instruction acquisition process, S13...Overlap area adjustment process, S14...Second print data generation process, S15...Second print process, S16...Decision process, SI...Control signal, Sk1...Control signal, TCP...Tool center point, VBS...Offset potential, VHV...Power supply potential, VS...Virtual space, W...Workpiece, WF...Face, dCom...Waveform specification signal, θ...Angle.

Claims

1. A control method for controlling the operation of a three-dimensional object printing apparatus having a liquid discharge head that discharges liquid toward a workpiece, and a moving mechanism that moves the liquid discharge head, A trajectory information generation step generates trajectory information relating to the movement trajectory of the moving mechanism that moves the liquid discharge head, A correspondence information generation step generates correspondence information that associates the aforementioned trajectory information, head information relating to the liquid ejection head, and first image information relating to the first image to be printed. A storage step for storing the aforementioned correspondence information, The process includes a print data generation step that generates print data for printing the second image based on the correspondence information and second image information relating to the second image to be printed, A control method characterized by the following:

2. The correspondence information includes pixel information that shows the correspondence between the nozzle of the liquid discharge head in the moving trajectory and the pixels of the print area of ​​the workpiece. The control method according to feature 1.

3. The correspondence information includes distance information relating to the distance between the nozzle of the liquid discharge head and the printing area in the moving trajectory. The control method according to feature 2.

4. The aforementioned moving trajectory is, The first printing track and, A second printing track adjacent to the first printing track in a sub-scanning direction that intersects the main scanning direction along the first printing track, The correspondence information includes first overlapping pixel information that shows the correspondence between pixels in the first overlapping region where a first region printed by liquid ejected from the liquid ejection head moving along the first printing trajectory and a second region printed by liquid ejected from the liquid ejection head moving along the second printing trajectory overlap, and the nozzle of the liquid ejection head. The control method according to feature 3.

5. The aforementioned moving trajectory is, The system further includes a third printing track adjacent to the first printing track in the main scanning direction along the first printing track, The correspondence information includes second overlapping pixel information that shows the correspondence between pixels in a second overlapping region where the third region printed by the liquid ejected from the liquid ejection head moving along the third printing trajectory and the second region overlap, and the nozzle of the liquid ejection head. The control method according to feature 4.

6. The process further includes an overlapping region adjustment step for adjusting the size of the first overlapping region, The control method according to feature 4.

7. The correspondence information includes first distance information relating to the distance between the nozzle of the liquid discharge head and the first overlapping region, In the overlapping region adjustment step, the size of the first overlapping region is adjusted based on the first distance information. The control method according to feature 6.

8. The correspondence information further includes first angular information relating to the angle between the direction of liquid discharge from the nozzle of the liquid discharge head and the first overlapping region, In the overlapping region adjustment step, the size of the first overlapping region is adjusted based on the first angle information. The control method according to feature 6.

9. The process further includes an instruction acquisition step for acquiring instruction information related to user instructions, In the overlapping region adjustment step, the size of the first overlapping region is adjusted based on the instruction information. The control method according to feature 6.

10. The first overlapping region includes a step of changing the mask pattern for each liquid color to generate print data, The control method according to feature 4.

11. In the print data generation process, print data is generated for each liquid color based on the corresponding information. The control method according to feature 1.

12. In the print data generation process, the mask pattern is changed for each liquid color to generate the print data. The control method according to feature 11.

13. The aforementioned moving trajectory is, The first printing track and, A second printing track adjacent to the first printing track in a sub-scanning direction that intersects the main scanning direction along the first printing track, The correspondence information includes first overlapping pixel information that shows the correspondence between pixels in the first overlapping region where a first region printed by liquid discharged from the liquid discharge head moving along the first printing trajectory and a second region printed by liquid discharged from the liquid discharge head moving along the second printing trajectory overlap, and the nozzles of the liquid discharge head. The mask pattern used in the first region and the mask pattern used in the second region are the same. The control method according to feature 12.

14. A liquid dispensing head that dispenses liquid towards the workpiece, It has a moving mechanism for moving the liquid discharge head, The moving mechanism generates trajectory information relating to the movement path of the liquid discharge head, Correspondence information is generated by associating the aforementioned trajectory information, head information relating to the liquid ejection head, and first image information relating to the first image to be printed. Based on the correspondence information and the second image information relating to the second image to be printed, print data for printing the second image is generated. A three-dimensional object printing apparatus characterized by the following features.

15. A control method for controlling the operation of a three-dimensional object printing apparatus having a liquid discharge head that discharges liquid toward a workpiece, and a moving mechanism that moves the liquid discharge head, A trajectory information generation step generates trajectory information relating to the movement trajectory of the moving mechanism that moves the liquid discharge head, The first printing process involves printing the first image, The process includes a second printing step of printing a second image different from the first image, In both the first printing step and the second printing step, the moving mechanism moves the liquid discharge head along the moving trajectory. A control method characterized by the following:

16. A liquid dispensing head that dispenses liquid towards the workpiece, A moving mechanism for moving the liquid discharge head, The device has a storage unit that stores correspondence information relating to the movement path of the moving mechanism that moves the liquid ejection head, head information relating to the liquid ejection head, and first image information relating to the first image to be printed. Based on the correspondence information and the second image information relating to the second image to be printed, print data for printing the second image is generated. A three-dimensional object printing apparatus characterized by the following features.

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