Three-dimensional object printing device and three-dimensional object printing method

Abstract

A three-dimensional object printing device comprises: a liquid ejection head having a nozzle surface provided with a plurality of nozzles for ejecting liquid; a moving mechanism which changes the relative position and posture of the liquid ejection head with respect to a three-dimensional workpiece; and a control unit which controls the respective drives of the liquid ejection head and the moving mechanism. The workpiece comprises a first surface and a second surface which forms a convex angle with the first surface. When an axis of a scanning direction of the liquid ejection head relative to the workpiece in a first printing operation for printing on the first surface is set as a first scanning axis and a normal vector of the nozzle surface in the first printing operation is set as a first ejection vector, the control unit controls the drive of the moving mechanism in such a manner that the first ejection vector has a component in a direction toward the second surface along the first scanning axis.

Description

Technical Field

[0001] The invention relates to a three-dimensional object printing device and a three-dimensional object printing method. Background Art

[0002] A three-dimensional printing device for printing on the surface of a three-dimensional object by inkjet is known. For example, the device described in Patent Document 1 has a multi-jointed robot arm and a printing head mounted on the hand of the robot arm. In Patent Document 1, printing is continuously performed on two adjacent sides of the four sides of a quadrangular prism-shaped workpiece. Here, the ink ejection surface of the printing head is maintained in a state of being parallel to and opposite to the side of the workpiece.

[0003] In the device described in Patent Document 1, there is a problem that, since the ink ejection surface is always parallel to the side of the workpiece to be printed, when printing is performed near the angle formed by two adjacent side surfaces of the workpiece, even if only one of the two side surfaces is to be printed, the ink will adhere to the other side surface.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2017-71173 Summary of the invention

[0005] In order to solve the above problems, one method of the three-dimensional object printing device involved in the present invention includes: a liquid ejection head, which has a nozzle surface provided with a plurality of nozzles for ejecting liquid; a moving mechanism, which changes the relative position and posture of the liquid ejection head with respect to the three-dimensional workpiece, the workpiece having a first surface and a second surface that forms a convex angle with the first surface, and when the axis of the scanning direction of the liquid ejection head relative to the workpiece in a first printing action of printing on the first surface is set as a first scanning axis, and the normal vector of the nozzle surface in the first printing action is set as a first ejection vector, the first ejection vector has a component in the direction along the first scanning axis toward the second surface.

[0006] Another embodiment of the three-dimensional object printing device involved in the present invention comprises: a liquid ejection head, which has a nozzle face provided with a plurality of nozzles for ejecting liquid; and a moving mechanism, which changes the relative position and posture of the liquid ejection head with respect to the three-dimensional workpiece, wherein the nozzle face has a nozzle row composed of a plurality of arranged nozzles, a first end in a direction intersecting the arrangement direction of the plurality of nozzles, and a second end on the opposite side of the first end, the workpiece has a first surface, and a second surface that forms a convex angle with the first surface, and the three-dimensional object printing device performs a first printing action, wherein the first printing action is an action of printing on the first surface while the nozzle face is tilted relative to the first surface in such a manner that the distance between the first end and the first surface is greater than the distance between the second end and the first surface, and the distance between the first end and the second surface is less than the distance between the second end and the second surface.

[0007] Another embodiment of the three-dimensional object printing device involved in the present invention comprises: a liquid ejection head, which has a nozzle face provided with a plurality of nozzles for ejecting liquid; and a moving mechanism, which changes the relative position and posture of the liquid ejection head with respect to the three-dimensional workpiece, wherein the nozzle face has a nozzle row composed of a plurality of arranged nozzles, a first end in a direction intersecting the arrangement direction of the plurality of nozzles, and a second end on the opposite side of the first end, and the workpiece has a first surface and a second surface that forms a convex angle with the first surface, and when an axis along a scanning direction of the liquid ejection head relative to the workpiece in a first printing operation for printing on the first surface is set as a first scanning axis, and a normal direction of the nozzle face in the first printing operation is set as a first ejection direction, in the first printing operation, the angle formed by the first scanning axis and the first ejection direction is an acute angle, and the liquid is ejected at a position closer to the angle than the positions of the plurality of nozzles in the direction along the first scanning axis.

[0008] One embodiment of the three-dimensional object printing method involved in the present invention is a three-dimensional printing method that uses a liquid ejection head having a nozzle surface provided with multiple nozzles for ejecting liquid to print a three-dimensional workpiece. In the three-dimensional object printing method, the workpiece has a first surface and a second surface that forms a convex angle with the first surface. When the axis of the scanning direction of the liquid ejection head relative to the workpiece in a first printing action of printing on the first surface is set as a first scanning axis, and the normal vector of the nozzle surface in the first printing action is set as a first ejection vector, the first ejection vector has a component in the direction toward the second surface along the first scanning axis. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is a perspective view schematically showing the three-dimensional object printing apparatus according to the first embodiment.

[0010] Figure 2 It is a block diagram showing the electrical structure of the three-dimensional object printing apparatus according to the first embodiment.

[0011] Figure 3 It is a perspective view showing a schematic structure of the liquid ejecting head unit in the first embodiment.

[0012] Figure 4 It is a cross-sectional view showing a structural example of the liquid ejecting head in the first embodiment.

[0013] Figure 5 It is a plan view showing a structural example of the pressure regulating valve in the first embodiment.

[0014] Figure 6 for Figure 5 AA line section view in.

[0015] Figure 7 This is a diagram for explaining the first printing operation in the first embodiment.

[0016] Figure 8 This is a diagram for explaining the second printing operation in the first embodiment.

[0017] Fig. 9 This is a diagram for explaining the first printing operation in the second embodiment.

[0018] Fig.10 A diagram for explaining the second printing operation in the second embodiment.

[0019] Fig.11 This is a diagram for explaining the third printing operation in the third embodiment.

[0020] Fig.12 A diagram for explaining the first printing operation in Modification 1.

[0021] Fig.13 A diagram for explaining the second printing operation in Modification 1. DETAILED DESCRIPTION

[0022] Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. In addition, in each of the drawings, the size or scale of each part is appropriately different from the actual situation, and there are also parts schematically shown for easy understanding. In addition, in the following description, as long as there is no special description to limit the present invention, the scope of the present invention is not limited to these modes.

[0023] The following description is appropriately performed using the mutually intersecting X-axis, Y-axis, and Z-axis. In addition, a direction along the X-axis is referred to as the X1 direction, and the direction opposite to the X1 direction is referred to as the X2 direction. Similarly, directions opposite to each other along the Y-axis are referred to as the Y1 direction and the Y2 direction. In addition, directions opposite to each other along the Z-axis are referred to as the Z1 direction and the Z2 direction.

[0024] Here, the X-axis, Y-axis, and Z-axis are coordinate axes of a base coordinate system set in a space where a workpiece W and a base 210 described later are provided. Typically, the Z-axis is a vertical axis, and the Z2 direction corresponds to the downward direction in the vertical direction. In addition, the Z-axis may not be a vertical axis. In addition, although the X-axis, Y-axis, and Z-axis are typically orthogonal to each other, this is not limited to this, and there are also non-orthogonal situations. For example, the X-axis, Y-axis, and Z-axis only need to intersect each other at an angle within a range of 80° or more and 100° or less.

[0025] 1. First Implementation

[0026] 1-1. Overview of 3D Object Printing Device

[0027] Figure 1 1 is a perspective view showing an overview of a three-dimensional object printing apparatus 100 according to a first embodiment. The three-dimensional object printing apparatus 100 is a device for printing on a surface of a workpiece W, which is an example of a three-dimensional object, by an inkjet method. The workpiece W has a first surface WF1 and a second surface WF2 that form a corner WC that is bent or curved into a convex shape.

[0028] exist Figure 1 In the example shown, the workpiece W is a rectangular parallelepiped, and the first surface WF1 and the second surface WF2 are orthogonal to each other, and their intersection forms a corner WC. Here, the first surface WF1 is a plane facing the Z1 direction. The second surface WF2 is a plane facing the X1 direction. In addition, the shape of the workpiece W only needs to have two surfaces that form a convex angle as the first surface and the second surface, and is not limited to Figure 1 The shape of the workpiece W may be any shape other than the example shown. Although the details will be described in the modified examples below, for example, the shape of the workpiece W may be a shape in which the angle formed by the first surface WF1 and the second surface WF2 is less than 90°, or a shape in which the angle formed by the first surface WF1 and the second surface WF2 is greater than 90°. In addition, the setting posture of the workpiece W is not limited to Figure 1 The examples shown are arbitrary postures.

[0029] exist Figure 1 In the example shown, the three-dimensional object printing device 100 is an inkjet printer using a vertical multi-joint robot arm. Figure 1As shown, the 3D printing apparatus 100 includes a robot arm 200, a liquid ejection head unit 300, a liquid storage portion 400, a supply channel 500, and a control device 600. First, each component of the 3D printing apparatus 100 will be briefly described in sequence.

[0030] The robot arm 200 is an example of a moving mechanism that changes the position and posture of the liquid ejection head unit 300 relative to the workpiece W. Figure 1 In the example shown, the robot arm 200 is a so-called six-axis vertical multi-joint robot arm. Specifically, the robot arm 200 has a base 210 and an arm 220.

[0031] The base 210 is a base for supporting the arm 220. Figure 1 In the example shown, the base 210 is fixed to a setting surface such as a bottom plate facing the Z1 direction by screwing or the like. In addition, the setting surface to which the base 210 is fixed may be a surface facing any direction, and is not limited to Figure 1 The examples shown may also be surfaces of a wall, a ceiling, a movable flatbed truck, or the like.

[0032] The arm 220 is a six-axis robot arm having a base end mounted on the base 210 and a tip end whose position and posture are three-dimensionally changed relative to the base end. Specifically, the arm 220 has arms 221, 222, 223, 224, 225, and 226, which are connected in this order.

[0033] The arm 221 is connected to the base 210 via the joint 231 so as to be rotatable around the first rotation axis O1. The arm 222 is connected to the arm 221 via the joint 232 so as to be rotatable around the second rotation axis O2. The arm 223 is connected to the arm 222 via the joint 233 so as to be rotatable around the third rotation axis O3. The arm 224 is connected to the arm 223 via the joint 234 so as to be rotatable around the fourth rotation axis O4. The arm 225 is connected to the arm 224 via the joint 235 so as to be rotatable around the fifth rotation axis O5. The arm 226 is connected to the arm 225 via the joint 236 so as to be rotatable around the sixth rotation axis O6.

[0034] exist Figure 1In the example shown, the joints 231 to 236 are mechanisms for connecting one of the two adjacent arms so that it can rotate relative to the other. Although not shown in the figure, a driving mechanism for rotating one of the two adjacent arms relative to the other is provided on each of the joints 231 to 236. The driving mechanism includes, for example, a motor that generates a driving force for the rotation, a speed reducer that reduces the speed of the driving force and outputs it, and an encoder such as a rotary encoder that detects the angle of the rotation. In addition, the driving mechanism corresponds to the following description. Figure 2 The arm drive mechanism 230 is shown.

[0035] The first rotation axis O1 is an axis perpendicular to the installation surface (not shown) to which the base 210 is fixed. The second rotation axis O2 is an axis perpendicular to the first rotation axis O1. The third rotation axis O3 is an axis parallel to the second rotation axis O2. The fourth rotation axis O4 is an axis perpendicular to the third rotation axis O3. The fifth rotation axis O5 is an axis perpendicular to the fourth rotation axis O4. The sixth rotation axis O6 is an axis perpendicular to the fifth rotation axis O5.

[0036] In addition, for these rotation axes, "perpendicular" includes not only the case where the angle formed by the two rotation axes is strictly 90°, but also the case where the angle formed by the two rotation axes deviates within the range of 90°±5°. Similarly, "parallel" includes not only the case where the two rotation axes are strictly parallel, but also the case where one of the two rotation axes is inclined within the range of ±5° relative to the other.

[0037] The liquid ejection head unit 300 is attached as an end effector to the tip of the above arm 221, that is, to the arm 226.

[0038] The liquid ejection head unit 300 is a mechanism having a liquid ejection head 310 that ejects ink as an example of liquid toward the workpiece W. In the present embodiment, the liquid ejection head unit 300 has, in addition to the liquid ejection head 310, a pressure regulating valve 320 that regulates the pressure of the ink supplied to the liquid ejection head 310, and a displacement sensor 330 that measures the distance from the workpiece W. Since they are fixed together on the arm 226, the relative positions and postures are fixed.

[0039] The liquid ejection head 310 and the pressure regulating valve 320 will be described in detail later. The displacement sensor 330 is, for example, an optical displacement sensor that measures the displacement amount when moving from a certain position to another position. In addition, the displacement sensor 330 only needs to be provided as required, and may also be omitted. Figure 1In the illustrated example, the number of the liquid ejection head 310 and the number of the pressure regulating valve 320 included in the liquid ejection head unit 300 is one, but the number is not limited to one. Figure 1 In the example shown, there may be more than two. In addition, the installation positions of the pressure regulating valve 320 and the displacement sensor 330 are not limited to the arm 226, and may be, for example, on other arms.

[0040] The liquid storage portion 400 is a container for storing ink. The liquid storage portion 400 is, for example, a bag-shaped ink bag formed of a flexible film. The ink stored in the liquid storage portion 400 is, for example, an ink containing a color material such as a dye or a pigment. In addition, the type of ink stored in the liquid storage portion 400 is not limited to ink containing a color material, and for example, it can also be an ink containing a conductive material such as a metal powder. In addition, the ink can also have a curing property such as ultraviolet curing. In the case where the ink has a curing property such as ultraviolet curing, for example, an ultraviolet irradiation mechanism is mounted on the liquid ejection head unit 300.

[0041] exist Figure 1 In the example shown, the liquid storage portion 400 is fixed to a wall, a ceiling, a column, or the like so as to always be located closer to the liquid ejection head 310 in the Z1 direction. That is, the liquid storage portion 400 is located above the moving area of ​​the liquid ejection head 310 in the vertical direction. Therefore, even without using a mechanism such as a pump, ink can be supplied from the liquid storage portion 400 to the liquid ejection head 310 at a predetermined pressure.

[0042] The liquid storage portion 400 may be provided at a position where ink can be supplied from the liquid storage portion 400 to the liquid ejecting head 310 at a predetermined pressure, and may be provided vertically below the liquid ejecting head 310. In this case, for example, ink may be supplied from the liquid storage portion 400 to the liquid ejecting head 310 at a predetermined pressure using a pump.

[0043] The supply flow path 500 is a flow path for supplying ink from the liquid storage portion 400 to the liquid ejection head 310. A pressure regulating valve 320 is provided in the middle of the supply flow path 500. Therefore, even if the positional relationship between the liquid ejection head 310 and the liquid storage portion 400 changes, the pressure fluctuation of the ink in the liquid ejection head 310 can be reduced.

[0044] The supply channel 500 is divided into an upstream channel 510 and a downstream channel 520 by the pressure regulating valve 320. That is, the supply channel 500 includes the upstream channel 510 that connects the liquid storage unit 400 with the pressure regulating valve 320 and the downstream channel 520 that connects the pressure regulating valve 320 with the liquid ejection head 310.

[0045] The upstream flow channel 510 and the downstream flow channel 520 are respectively constituted by the internal space of a tube body, for example. Here, the tube body used in the upstream flow channel 510 is constituted by an elastic material such as a rubber material or an elastomer material, and has flexibility. In this way, by using a flexible tube body to constitute the upstream flow channel 510, changes in the relative positional relationship between the liquid storage portion 400 and the pressure regulating valve 320 are allowed. Therefore, even if the position and posture of the liquid storage portion 400 remain fixed and the position or posture of the liquid ejection head 310 changes, ink can be supplied from the liquid storage portion 400 to the pressure regulating valve 320. On the other hand, the tube body used in the downstream flow channel 520 may not have flexibility. Therefore, the tube body used in the downstream flow channel 520 may be constituted by an elastic material such as a rubber material or an elastomer material, or by a hard material such as a resin material.

[0046] In addition, a part of the upstream flow channel 510 may also be composed of a non-flexible member. In addition, the downstream flow channel 520 is not limited to a structure using a tube. For example, a part or all of the downstream flow channel 520 may be a structure having a distribution flow channel that distributes the ink from the pressure regulating valve 320 to a plurality of locations, or may be formed in an integrated manner with the liquid ejection head 310 or the pressure regulating valve 320.

[0047] The control device 600 is a device that controls the driving of each part of the 3D printing apparatus 100. Here, the control device 600 controls the driving of the liquid ejection head 310 and the robot arm 200. The control device 600 will be described in detail together with the following description of the electrical structure of the 3D printing apparatus 100.

[0048] 1-2. Electrical structure of 3D printing device

[0049] Figure 2 is a block diagram showing the electrical structure of the 3D object printing apparatus 100 according to the first embodiment. Figure 2 , electrical components of the components of the three-dimensional object printing device 100 are shown. Figure 2 As shown, the control device 600 includes a processing circuit 610 , a storage circuit 620 , a power supply circuit 630 , and a drive signal generating circuit 640 .

[0050] In addition, the hardware structure included in the control device 600 described below may be appropriately divided. For example, the arm control unit 612 and the drive signal generating circuit 640 of the control device 600 may be separately provided in different hardware structures. In addition, part or all of the functions of the control device 600 may be implemented by an external device such as a PC (personal computer) connected to the three-dimensional object printing device 100 via a network such as a LAN (Local Area Network) or the Internet.

[0051] The processing circuit 610 has the function of controlling the operation of each part of the three-dimensional object printing device 100 and the function of processing various data. The processing circuit 610 includes, for example, one or more processors such as CPUs (Central Processing Units). In addition, the processing circuit 610 may also include a programmable logic device such as an FPGA (field-programmable gate array) instead of or in addition to the CPU.

[0052] The storage circuit 620 stores various programs such as the program P executed by the processing circuit 610 and various data such as the printing data Img processed by the processing circuit 610. The storage circuit 620 includes, for example, 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) or a semiconductor memory, or both. The printing data Img is supplied from an external device 700 such as a personal computer. In addition, the storage circuit 620 may be configured as a part of the processing circuit 610.

[0053] The power supply circuit 630 receives power from a commercial power supply (not shown) and generates various predetermined potentials. The generated various potentials are appropriately supplied to various parts of the three-dimensional object printing device 100. The power supply circuit 630 generates, for example, a power supply potential VHV and an offset potential VBS. The offset potential VBS is supplied to the liquid ejection head unit 300. In addition, the power supply potential VHV is supplied to the drive signal generation circuit 640.

[0054] The drive signal generating circuit 640 is a circuit for generating a drive signal Com for driving each piezoelectric element 311 of the liquid ejection head 310. Specifically, the drive signal generating circuit 640 has, for example, a DA conversion circuit and an amplifier circuit. In the drive signal generating circuit 640, the waveform designation signal dCom described later from the processing circuit 610 is converted from a digital signal to an analog signal by the DA conversion circuit, and the amplifier circuit amplifies the analog signal using the power supply potential VHV from the power supply circuit 630, thereby generating the drive signal Com. Here, the signal of the waveform actually supplied to the piezoelectric element 311 in the waveform included in the drive signal Com is the drive pulse PD. The drive pulse PD is supplied from the drive signal generating circuit 640 to the piezoelectric element 311 via the drive circuit 340 for driving the piezoelectric element 311. The drive circuit 340 switches whether to supply at least a part of the waveform included in the drive signal Com as the drive pulse PD based on the control signal SI described later.

[0055] In the above control device 600, the processing circuit 610 executes the program P stored in the storage circuit 620 to control the operation of each part of the 3D object printing apparatus 100. Specifically, the processing circuit 610 functions as an information acquisition unit 611, an arm control unit 612, and a discharge control unit 613 by executing the program P.

[0056] The information acquisition unit 611 acquires various information required for driving the robot arm 200 and the liquid ejection head unit 300. Specifically, the information acquisition unit 611 acquires the print data Img from the external device 700, the information D1 from the encoder included in the arm driving mechanism 230, and the information D2 from the displacement sensor 330. In addition, the information acquisition unit 611 appropriately reads and acquires the information stored in the storage circuit 620, or causes the storage circuit 620 to appropriately store the acquired various information.

[0057] The arm control unit 612 controls the driving of the robot arm 200 based on the information from the information acquisition unit 611. Specifically, the arm control unit 612 generates a control signal Sk based on the three-dimensional shape data of the workpiece W and the information D1 from the arm driving mechanism 230. The control signal Sk controls the driving of the motor included in the arm driving mechanism 230 so that the liquid ejection head 310 is in a desired position and posture. The three-dimensional shape data is included in the printing data Img, for example, or is obtained by measurement using a displacement sensor 330 or the like.

[0058] In addition, the correspondence between the information D1 and the position and posture of the liquid ejection head is obtained in advance through calibration, etc., and is stored in the storage circuit 620. Moreover, the arm control unit 612 obtains information related to the actual position and posture of the liquid ejection head 310 based on the information D1 from the actual arm drive mechanism 230 and the correspondence. On this basis, the control is implemented using the information related to the position and posture. In addition, the arm control unit 612 can also use the information D2 from the displacement sensor 330 to appropriately adjust the control signal Sk so that the distance between the liquid ejection head 310 and the surface of the workpiece W is maintained within a predetermined range.

[0059] In particular, the arm control unit 612 controls the posture of the liquid ejecting head 310 so that printing is performed on the first surface WF1 or the second surface WF2 over a range including the corner WC of the workpiece W.

[0060] The ejection control unit 613 controls the drive of the liquid ejection head unit 300 based on the information from the information acquisition unit 611. Specifically, the ejection control unit 613 generates a control signal SI and a waveform designation signal dCom based on the printing data Img. The control signal SI is a digital signal for designating the operating state of the piezoelectric element 311 described later that is possessed by the liquid ejection head 310. Here, the control signal SI may also include other signals such as a timing signal for specifying the drive timing of the piezoelectric element 311. The timing signal is generated, for example, based on the information D1 from the encoder included in the arm drive mechanism 230. The waveform designation signal dCom is a digital signal for specifying the waveform of the drive signal Com.

[0061] 1-3. Liquid ejection head and pressure regulating valve

[0062] Figure 3 It is a perspective view showing a schematic structure of the liquid ejecting head unit 300 according to the first embodiment.

[0063] The following description is appropriately performed using the mutually intersecting a-axis, b-axis, and c-axis. In addition, a direction along the a-axis is referred to as the a1 direction, and the direction opposite to the a1 direction is referred to as the a2 direction. Similarly, the directions opposite to each other along the b-axis are referred to as the b1 direction and the b2 direction. In addition, the directions opposite to each other along the c-axis are referred to as the c1 direction and the c2 direction.

[0064] Here, the a-axis, b-axis, and c-axis are coordinate axes of the tool coordinate system set in the liquid ejection head unit 300, and their relative positions and postures with the aforementioned X-axis, Y-axis, and Z-axis change according to the movement of the aforementioned robot arm 200. Figure 3In the example shown, the c-axis is parallel to the sixth rotation axis O6 described above. The a-axis, b-axis, and c-axis are typically orthogonal to each other, but are not limited thereto, and may intersect at an angle within a range of 80° to 100°, for example.

[0065] As described above, the liquid ejection head unit 300 has the liquid ejection head 310, the pressure regulating valve 320, and the displacement sensor 330. Figure 3 The support is provided by the support body 350 shown by the double dotted line.

[0066] The support body 350 is made of, for example, a metal material and is a substantially rigid body. Figure 3 The middle support body 350 has a flat box shape, but the shape of the support body 350 is not particularly limited and may be any shape.

[0067] The above-mentioned support body 350 is mounted on the top end of the arm 220, that is, the arm 226. Therefore, the liquid ejection head 310, the pressure regulating valve 320 and the displacement sensor 330 are fixed to the arm 226, respectively.

[0068] exist Figure 3 In the example shown, the pressure regulating valve 320 is located in the c1 direction relative to the liquid ejection head 310. The displacement sensor 330 is located in the a2 direction relative to the liquid ejection head 310.

[0069] In addition, Figure 3 In the illustrated example, a portion of the downstream flow channel 520 of the supply flow channel 500 is constituted by a flow channel member 521. The flow channel member 521 has a flow channel for distributing the ink from the pressure regulating valve 320 to a plurality of locations of the liquid ejection head 310. The flow channel member 521 is, for example, a laminate of a plurality of substrates made of a resin material, and grooves or holes for the flow channel of the ink are appropriately provided on each substrate.

[0070] The liquid ejection head 310 has a nozzle face F and a plurality of nozzles N opening on the nozzle face F. Figure 3 In the example shown, the normal direction of the nozzle surface F is the c2 direction, and the plurality of nozzles N are divided into a first nozzle row L1 and a second nozzle row L2 arranged in a manner spaced apart from each other in the direction along the a-axis. The first nozzle row L1 and the second nozzle row L2 are respectively a set of a plurality of nozzles N arranged in a straight line in the direction along the b-axis. Here, the elements associated with each nozzle N of the first nozzle row L1 and the elements associated with each nozzle N of the second nozzle row L2 in the liquid ejection head 310 are substantially symmetrical structures in the direction along the a-axis.

[0071] However, the positions of the plurality of nozzles N in the first nozzle row L1 and the plurality of nozzles N in the second nozzle row L2 in the direction along the b-axis may be identical to or different from each other. In addition, elements associated with each nozzle N in one of the first nozzle row L1 and the second nozzle row L2 may be omitted. Hereinafter, a structure in which the positions of the plurality of nozzles N in the first nozzle row L1 and the plurality of nozzles N in the second nozzle row L2 in the direction along the b-axis are identical to each other is exemplified.

[0072] Figure 4 2 is a cross-sectional view showing a structural example of the liquid ejection head 310 according to the first embodiment. Figure 4 As shown, the liquid ejection head 310 includes a flow path substrate 312 , a pressure chamber substrate 313 , a nozzle plate 314 , a vibration absorber 315 , a vibration plate 316 , a plurality of piezoelectric elements 311 , a wiring substrate 317 , and a frame portion 318 .

[0073] The flow path substrate 312 and the pressure chamber substrate 313 form a flow path for supplying ink to the plurality of nozzles N. The flow path substrate 312 and the pressure chamber substrate 313 are laminated in this order in the c1 direction. The flow path substrate 312 and the pressure chamber substrate 313 are respectively plate-shaped members that are long and narrow in the direction along the b-axis. The flow path substrate 312 and the pressure chamber substrate 313 are bonded to each other, for example, by an adhesive.

[0074] In the region located closer to the c1 direction than the pressure chamber substrate 313, a vibration plate 316, a wiring substrate 317, a frame portion 318, and a drive circuit 340 are provided. On the other hand, in the region located closer to the c2 direction than the flow path substrate 312, a nozzle plate 314 and a vibration absorber 315 are provided. These elements are schematically plate-like members that are elongated in the direction along the b-axis like the flow path substrate 312 and the pressure chamber substrate 313, and are bonded to each other, for example, by an adhesive.

[0075] The nozzle plate 314 is a plate-shaped member on which a plurality of nozzles N are formed. Each of the plurality of nozzles N is a circular through hole through which ink passes. The nozzle plate 314 is manufactured, for example, by processing a single crystal silicon substrate using semiconductor manufacturing technology using a processing technology such as dry etching or wet etching. However, in the manufacture of the nozzle plate 314, other known methods and materials may be appropriately used.

[0076] Here, the nozzle surface F mentioned above is a surface that expands from the opening at one end in the c2 direction of the nozzle N in a direction perpendicular to the c-axis among the surfaces constituting the outer shape of the liquid ejection head 310. Figure 4In the example shown, the surface of the liquid ejection head 310 facing the c2 direction is the nozzle surface F, and the nozzle surface F includes the surface of the nozzle plate 314 facing the c2 direction. In addition, one end of the nozzle surface F in the a2 direction, that is, the portion of the nozzle surface F located closest to the a2 direction, is the first end E1, and one end of the nozzle surface F in the a1 direction, that is, the portion of the nozzle surface F located closest to the a1 direction, is the second end E2. In this embodiment, the first end E1 and the second end E2 are edges along the b-axis. Between the first end E1 and the second end E2 on the nozzle surface F, the first nozzle array L1 and the second nozzle array L2 described above are provided.

[0077] In addition, in the case of a structure that covers a part of the surface of the nozzle plate 314 facing the c2 direction, the surface of the structure facing the c2 direction can also be understood as a part of the nozzle surface F. As an example of such a structure, a head cover can be cited. The head cover is a structure that covers at least a part of the surface of the laminated body composed of the nozzle plate 314, the vibration absorber 315, the flow channel substrate 312, and the frame part 318, and is fixed to the laminated body by an adhesive. The head cover is formed by bending a plate-like member made of a metal material such as stainless steel. When such a head cover is used, one end of the head cover in the a1 direction can be understood as the first end E1, and one end of the head cover in the a2 direction can be understood as the second end E2. When there is a structure such as a support body 350 described later on the extension line of the nozzle surface F, one end of the structure in the a1 direction can be understood as the first end E1, and one end of the structure in the a2 direction can be understood as the second end E2. In addition, although the outer shape of the nozzle surface F is typically a rectangle, it is not limited to this and may be any outer shape.

[0078] On the flow channel substrate 312, a space Ra, a plurality of supply flow channels 312a, a plurality of connecting flow channels 312b, and a supply liquid chamber 312c are provided for the first nozzle column L1 and the second nozzle column L2, respectively. The space Ra is an elongated opening extending in the direction along the b-axis when viewed from above in the direction along the c-axis. The supply flow channel 312a and the connecting flow channel 312b are through holes formed for each nozzle N, respectively. The supply liquid chamber 312c is an elongated space extending in the direction along the b-axis across the plurality of nozzles N, and the space Ra and the plurality of supply flow channels 312a are connected to each other. Each of the plurality of connecting flow channels 312b overlaps with a nozzle N corresponding to the connecting flow channel 312b when viewed from above.

[0079] The pressure chamber substrate 313 is a plate-like component in which a plurality of pressure chambers Cv, called cavities, are formed for the first nozzle column L1 and the second nozzle column L2, respectively. The plurality of pressure chambers Cv are arranged in the direction along the b-axis. Each pressure chamber Cv is a long strip-shaped space formed for each nozzle N and extending in the direction along the a-axis when viewed from above. Similar to the nozzle plate 314 described above, the flow channel substrate 312 and the pressure chamber substrate 313 are manufactured, for example, by processing a single crystal silicon substrate using semiconductor manufacturing technology. However, in the manufacture of each of the flow channel substrate 312 and the pressure chamber substrate 313, other well-known methods and materials may also be appropriately used.

[0080] The pressure chamber Cv is a space located between the flow channel substrate 312 and the vibration plate 316. For each of the first nozzle column L1 and the second nozzle column L2, a plurality of pressure chambers Cv are arranged in the direction along the b-axis. In addition, the pressure chamber Cv is connected to the communication flow channel 312b and the supply flow channel 312a. Therefore, the pressure chamber Cv is connected to the nozzle N via the communication flow channel 312b, and is connected to the space Ra via the supply flow channel 312a and the supply liquid chamber 312c.

[0081] A vibration plate 316 is arranged on the surface of the pressure chamber substrate 313 facing the c2 direction. The vibration plate 316 is a plate-shaped member capable of elastic vibration. The vibration plate 316 has, for example, an elastic film composed of silicon oxide (SiO2) and an insulating film composed of zirconium oxide (ZrO2), and they are laminated together. The elastic film is formed, for example, by thermally oxidizing one surface of a single crystal silicon substrate. The insulating film is formed, for example, by forming a zirconium layer by sputtering and thermally oxidizing the layer.

[0082] On the surface of the vibration plate 316 facing the c1 direction, a plurality of piezoelectric elements 311 corresponding to each nozzle N are arranged for each of the first nozzle column L1 and the second nozzle column L2. Each piezoelectric element 311 is a passive element that is deformed by the supply of the aforementioned drive pulse PD. Each piezoelectric element 311 is in the shape of a strip extending in the direction along the a-axis when viewed from above. The plurality of piezoelectric elements 311 are arranged in the direction along the b-axis in a manner corresponding to the plurality of pressure chambers Cv. When the vibration plate 316 vibrates in a manner linked to the deformation of the piezoelectric element 311, the pressure in the pressure chamber Cv changes, thereby causing the ink to be ejected from the nozzle N toward the c2 direction.

[0083] The frame portion 318 is a housing for storing ink supplied to the plurality of pressure chambers Cv. Figure 4As shown, in the frame portion 318 of the present embodiment, a space Rb is formed for each of the first nozzle column L1 and the second nozzle column L2. The space Rb of the frame portion 318 is connected to the space Ra of the flow path substrate 312. The space formed by the space Ra and the space Rb functions as a liquid storage chamber (liquid reservoir) R for storing the ink supplied to the plurality of pressure chambers Cv. Ink is supplied to the liquid storage chamber R via an inlet 318a formed in the frame portion 318. The ink in the liquid storage chamber R is supplied to the pressure chamber Cv via the supply liquid chamber 312c and each supply flow channel 312a. The vibration absorber 315 is a flexible film (plastic substrate) constituting the wall surface of the liquid storage chamber R, and absorbs the pressure fluctuation of the ink in the liquid storage chamber R.

[0084] The wiring substrate 317 is a plate-shaped member formed with wiring for electrically connecting the drive circuit 340 and the plurality of piezoelectric elements 311. The surface of the wiring substrate 317 facing the c2 direction is bonded to the vibration plate 316 via a plurality of conductive bumps T. On the other hand, the drive circuit 340 is mounted on the surface of the wiring substrate 317 facing the c1 direction.

[0085] The driving circuit 340 is an IC (Integrated Circuit) chip that outputs a driving signal and a reference voltage for driving each piezoelectric element 311. Specifically, the driving circuit 340 switches whether to supply the driving signal Com as a driving pulse PD to each of the plurality of piezoelectric elements 311 based on the control signal SI described above.

[0086] Although not shown in the figure, the end of the external wiring electrically connected to the control device 600 is bonded to the surface of the wiring substrate 317 facing the c1 direction. The external wiring is composed of a connecting component such as FPC (Flexible Printed Circuits) or FFC (Flexible Flat Cable). In addition, the wiring substrate 317 can also be FPC or FFC.

[0087] Figure 5 It is a plan view showing a configuration example of the pressure regulating valve 320 in the first embodiment. Figure 6 for Figure 5AA line cross-sectional view in FIG. The pressure regulating valve 320 is a valve mechanism that opens and closes according to the pressure of the ink in the liquid ejection head 310. By opening and closing, the pressure of the ink in the liquid ejection head 310 is maintained at a negative pressure within a predetermined range. Therefore, the meniscus of the ink formed in the nozzle N of the liquid ejection head 310 is stabilized. As a result, bubbles are prevented from entering the nozzle N or ink is prevented from overflowing from the nozzle N.

[0088] like Figure 6 As shown, the pressure regulating valve 320 includes a flow path member 321 , a sealing member 322 , a sealing member 323 , a valve body 324 , a biasing member 325 , and a biasing member 326 .

[0089] The flow channel component 321 is a structure having a flow channel Q that connects the upstream flow channel 510 and the downstream flow channel 520 in the supply flow channel 500 described above. The flow channel component 321 is made of a resin material such as polypropylene and is formed by injection molding or the like. Figure 5 As shown, a supply port P1 and a discharge port P2 are provided in the flow channel member 321. The supply port P1 and the discharge port P2 are connected via a flow channel Q. The upstream flow channel 510 is connected to the supply port P1. The downstream flow channel 520 is connected to the discharge port P2.

[0090] like Figure 6 As shown, the flow channel Q has an upstream liquid chamber Q1 and a downstream liquid chamber Q2. The upstream liquid chamber Q1 is a space communicating with the supply port P1 described above via a flow channel not shown. On the other hand, the downstream liquid chamber Q2 is a space communicating with the discharge port P2 described above via a flow channel not shown.

[0091] exist Figure 5 as well as Figure 6 In the example shown, the outer shape of the flow channel member 321 is a substantially plate-like shape with the a1 direction or the a2 direction being the thickness direction, and the upstream liquid chamber Q1 and the downstream liquid chamber Q2 are arranged in the thickness direction of the flow channel member 321. Here, a recessed portion 321a for forming the upstream liquid chamber Q1 is provided on the surface of the flow channel member 321 facing the a2 direction. On the other hand, a recessed portion 321b for forming the downstream liquid chamber Q2 is provided on the surface of the flow channel member 321 facing the a1 direction.

[0092] The shapes of the upstream liquid chamber Q1 and the downstream liquid chamber Q2 are circular when viewed from above in the a1 direction or the a2 direction. Figure 6 In the example shown, the area of ​​the downstream liquid chamber Q2 when viewed from above is larger than the area of ​​the upstream liquid chamber Q1 when viewed from above. Figure 5 as well as Figure 6The examples shown may be of any shape or size.

[0093] A valve seat 321c is provided between the upstream liquid chamber Q1 and the downstream liquid chamber Q2 in the flow channel component 321. The valve seat 321c is a partition wall that separates the upstream liquid chamber Q1 and the downstream liquid chamber Q2, and constitutes the bottom of each of the recessed portion 321b and the recessed portion 321a mentioned above. In other words, the valve seat 321c divides the flow channel Q into the upstream liquid chamber Q1 and the downstream liquid chamber Q2. A hole 321d is provided on the valve seat 321c. The hole 321d extends in the a1 direction or the a2 direction, and connects the upstream liquid chamber Q1 with the downstream liquid chamber Q2.

[0094] The sealing member 322 is a member that is joined to the flow channel member 321 by fusion or bonding to block the opening of the recessed portion 321a described above. The sealing member 322 is made of a resin material such as polypropylene (PP) or polyphenylene sulfide (PPS). The sealing member 322 has a portion 322a that constitutes a portion of the wall surface of the upstream liquid chamber Q1. The rigidity of the portion 322a is higher than that of the sealing member 322. Preferably, the portion 322a has a rigidity that is not substantially deformed by the pressure change of the ink in the upstream liquid chamber Q1.

[0095] The sealing member 323 is a sheet-like member that is joined to the flow channel member 321 by fusion or adhesion to block the opening of the recessed portion 321b described above. The sealing member 323 is made of a resin material such as polypropylene (PP) or polyphenylene sulfide (PPS). The sealing member 323 has a flexible portion 323a that is a part of the wall surface of the downstream liquid chamber Q2. The flexible portion 323a has flexibility that is deformed by bending according to the pressure of the ink in the downstream liquid chamber Q2.

[0096] Here, the flexible portion 323a separates the space open to the atmosphere from the downstream liquid chamber Q2, and since the pressure of the ink in the downstream liquid chamber Q2 is lower than the atmospheric pressure, a force toward the downstream liquid chamber Q2 is applied to the flexible portion 323a. Figure 6 In the example shown, a pressure plate 323b is provided at the central portion of the flexible portion 323a. The pressure plate 323b is made of a resin material such as polypropylene (PP) or polyphenylene sulfide (PPS). In addition, the pressure plate 323b may be formed integrally with the flexible portion 323a or may be formed separately from the flexible portion 323a. In addition, the pressure plate 323b only needs to be provided as required, and may be fixed to the valve body 324 or omitted.

[0097] The valve body 324 includes a shaft portion 324a, a flange portion 324b, and a sealing portion 324c. The shaft portion 324a and the flange portion 324b are made of a resin material such as polypropylene (PP) or polyphenylene sulfide (PPS), and are integrally formed by injection molding or the like.

[0098] The shaft portion 324a extends in the a1 direction or the a2 direction and is inserted into the hole 321d. The width of the shaft portion 324a is smaller than the width of the hole 321d. Therefore, the movement of the shaft portion 324a in the a1 direction or the a2 direction is allowed, and a gap that allows the flow of ink is formed between the outer peripheral surface of the shaft portion 324a and the inner peripheral surface of the hole 321d. One end of the shaft portion 324a in the a1 direction is arranged in the downstream side liquid chamber Q2 and contacts the pressure plate 323b. On the other hand, one end of the shaft portion 324a in the a2 direction is arranged in the upstream side liquid chamber Q1.

[0099] The flange portion 324b is provided at one end of the shaft portion 324a in the a2 direction and is arranged in the upstream liquid chamber Q1. The width of the flange portion 324b is larger than the width of the hole 321d and smaller than the width of the upstream liquid chamber Q1 or the recess 321a. By making the width of the flange portion 324b larger than the width of the hole 321d, the sealing portion 324c can be interposed between the flange portion 324b and the valve seat 321c. In addition, by making the width of the flange portion 324b smaller than the width of the recess 321a, the movement of the flange portion 324b in the a1 direction or the a2 direction is allowed, and a gap that allows the flow of ink is formed between the outer peripheral surface of the flange portion 324b and the inner peripheral surface of the recess 321a.

[0100] The sealing portion 324c is arranged on the surface of the flange portion 324b so as to have a portion interposed between the valve seat 321c and the flange portion 324b. The sealing portion 324c is an elastic member and is made of a rubber material or an elastomer material such as a silicon-based or fluorine-based material.

[0101] The urging member 325 is an elastic body that is disposed in the upstream liquid chamber Q1 and urges the valve body 324 toward the valve seat 321c. Figure 6 In the example shown, the urging member 325 is a coil spring and is arranged between the valve body 324 and the sealing member 322 in a state of being compressed and deformed. Figure 6 In the example shown, the width of the coil spring is constant, but it is not limited to this. For example, the width of the coil spring can be expanded from one end toward the other end. In addition, the force applying member 325 only needs to be able to apply force to the valve body 324 toward the valve seat 321c, and is not limited to a coil spring. For example, it can also be a leaf spring.

[0102] The urging member 326 is an elastic body that is disposed in the downstream liquid chamber Q2 and adjusts the ease of the flexible deformation of the flexible portion 323a. Figure 6 In the example shown, the force applying member 326 is a coil spring and is arranged between the valve seat 321c and the pressure receiving plate 323b. Figure 6 In the example shown, the width of the coil spring is constant, but it is not limited to this. For example, the width of the coil spring can also be expanded from one end to the other end. In addition, the force applying member 326 is not limited to a coil spring, and it can also be a leaf spring, etc. In addition, the force applying member 326 only needs to be provided as needed, and can also be omitted.

[0103] In the above pressure regulating valve 320, in a normal state where the pressure of the ink in the downstream liquid chamber Q2 is maintained at a negative pressure within a predetermined range, the seal portion 324c is pressed against the valve seat 321c by the force of the force applying member 325, thereby isolating the upstream liquid chamber Q1 from the downstream liquid chamber Q2. That is, in a normal state, the flow path Q is blocked.

[0104] On the other hand, when the negative pressure of the ink in the downstream liquid chamber Q2 rises to a predetermined level or higher due to the ink ejection performed by the liquid ejection head 310, the negative pressure of the ink in the downstream liquid chamber Q2 rises to a predetermined level or higher. Figure 6 As shown by the double-dashed line in FIG, the pressure receiving plate 323b will displace the valve body 324 by overcoming the force of the force applying member 325 and the force applying member 326 accompanied by the flexible deformation of the flexible portion 323a. As a result, since a gap is formed between the sealing portion 324c and the valve seat 321c, the upstream liquid chamber Q1 and the downstream liquid chamber Q2 are connected through the hole 321d. That is, the flow channel Q is opened.

[0105] When the flow channel Q is opened, the ink from the liquid storage portion 400 is supplied from the upstream liquid chamber Q1 to the downstream liquid chamber Q2 via the hole 321d. Accompanying this supply, the negative pressure of the ink in the downstream liquid chamber Q2 is reduced. As a result, the seal portion 324c is again pressed against the valve seat 321c by the force of the force-applying member 325, thereby causing the upstream liquid chamber Q1 and the downstream liquid chamber Q2 to be isolated. As described above, by opening and closing the pressure regulating valve 320 according to the pressure of the ink in the liquid ejection head 310, the pressure of the ink in the downstream liquid chamber Q2 is maintained at a negative pressure within a predetermined range.

[0106] As described above, the three-dimensional object printing apparatus 100 includes a liquid ejection head 310, a robot arm 200 as an example of a moving mechanism, and a control device 600 as an example of a control unit. Here, the liquid ejection head 310 includes a nozzle face F, on which a plurality of nozzles N for ejecting ink as an example of a liquid are provided. The robot arm 200 changes the relative position and posture of the liquid ejection head 310 with respect to the three-dimensional workpiece W. The control device 600 controls the driving of each of the liquid ejection head 310 and the robot arm 200.

[0107] Here, as described above, the workpiece W has a first surface WF1 and a second surface WF2 that forms a corner WC that is bent or curved into a convex shape with the first surface WF1. The control device 600 performs a first printing operation by printing on the first surface WF1 in order to cover a range including the corner WC or its vicinity. The first printing operation is an operation of printing on the first surface WF1 accompanied by the movement of the liquid ejection head 310 in the direction of the first surface WF1. In addition, the control device 600 performs a second printing operation by printing on the second surface WF2 in order to cover a range including the corner WC or its vicinity. The second printing operation is an operation of printing on the second surface WF2 accompanied by the movement of the liquid ejection head 310 in the direction of the second surface WF2. The first printing operation and the second printing operation are described in detail below.

[0108] 1-4. Operation of 3D Object Printing Device and 3D Object Printing Method

[0109] Figure 7 This is a diagram for explaining the first printing operation in the first embodiment. Figure 8 This is a diagram for explaining the second printing operation in the first embodiment.

[0110] exist Figure 7 , the change in position of the liquid ejection head unit 300 when printing is performed on the first surface WF1 of the workpiece W over a range including the corner WC is shown. Figure 8 , the change in position of the liquid ejection head unit 300 when printing is performed on the second surface WF2 of the workpiece W over a range including the corner WC is shown. Figure 7 as well as Figure 8 In FIG. 1 , the first nozzle array L1 and the second nozzle array L2 are parallel to the Y axis. More specifically, in FIG. Figure 7 In the figure, the c2 direction is orthogonal to the Y axis and is between the X1 direction and the Z2 direction, the a2 direction is orthogonal to the Y axis and is between the X1 direction and the Z1 direction, the b axis is parallel to the Y axis, and in Figure 8In the diagram, the c2 direction is orthogonal to the Y axis and is between the X2 direction and the Z1 direction, the a2 direction is orthogonal to the Y axis and is between the X2 direction and the Z2 direction, and the b axis is parallel to the Y axis. Figure 7 as well as Figure 8 Although the center position of the liquid ejecting head 310 is illustrated as the position of the liquid ejecting head 310 , the position of any portion of the liquid ejecting head 310 may be understood as the position of the liquid ejecting head 310 .

[0111] like Figure 7 As shown, the first printing operation of this embodiment performs printing in the region RE1 of the first surface WF1 by ejecting ink from the liquid ejecting head 310 while moving the liquid ejecting head unit 300 from the position P1 to the position P2 along the first surface WF1 .

[0112] The position P1 is a position of the liquid ejection head 310 where the ink lands at an arbitrary position on the first surface WF1. The position P2 is a position of the liquid ejection head 310 where the ink lands at the corner WC or its vicinity, or a position farther from the position P1 in the X1 direction than the position, and where the ink from the liquid ejection head 310 does not land on the first surface WF1 but passes through an imaginary surface extending along the first surface WF1. Therefore, printing can be performed on the first surface WF1 over a range including the corner WC or its vicinity.

[0113] exist Figure 7 In the example shown, the position P2 is the position of the liquid ejection head 310 where the ink from the liquid ejection head 310 passes through the imaginary plane FV1 extending along the first surface WF1 instead of being ejected onto the first surface WF1. Although the position P2 may be located in the X1 direction relative to the angle WC when viewed along the Z axis, Figure 7 In the example shown, when viewed along the Z-axis, position P2 is located in the X2 direction relative to the corner WC. Therefore, in the first printing operation, when viewed in the direction perpendicular to the first surface WF1, that is, along the Z-axis, the paths of the plurality of nozzles N intersect with the corner WC. Therefore, in a state where the ink from the liquid ejection head 310 does not land on the first surface WF1 but passes through the imaginary surface FV1 extending along the first surface WF1, the moving speed of the liquid ejection head 310 can be gradually reduced, thereby eliminating the need for deceleration during the printing process for the region RE1. Therefore, the variation in the moving speed of the liquid ejection head 310 during the printing process for the region RE1 can be reduced. Reducing this variation has the advantage of easily improving the image quality of the printing for the region RE1.

[0114] In the first printing operation, the control device 600 controls the driving of the robot 200 so that the first ejection vector VD1 has a component DC1 in the direction along the first scanning axis AS1 and toward the second surface WF2. Here, as described above, the first scanning axis AS1 is an axis along the scanning direction DS1 of the liquid ejection head 310 relative to the workpiece W in the first printing operation for printing on the first surface WF1. Typically, the first scanning axis AS1 is an axis parallel to the first surface WF1. The first ejection vector VD1 is a normal vector of the nozzle surface F in the first printing operation. In addition, the direction of the first ejection vector VD1 is an example of a first ejection direction as a normal direction of the nozzle surface F in the first printing operation.

[0115] As described above, the control device 600 performs the first printing operation of printing on the first surface WF1 in a state where the nozzle surface F is tilted relative to the first surface WF1. That is, in the first printing operation, the angle θ1 formed by the first scanning axis AS1 and the direction of the first ejection vector VD1 is an acute angle, and the ink is ejected at a position closer to the angle WC than the positions of the plurality of nozzles N in the direction along the first scanning axis AS1.

[0116] Here, if Figure 7 As shown, the nozzle surface F includes a first nozzle row L1 and a second nozzle row L2 as an example of nozzles composed of a plurality of arranged nozzles N, a first end E1 in a direction intersecting the arrangement direction of the plurality of nozzles N, and a second end E2 on the opposite side to the first end E1. In addition, in the first printing operation, a distance L11 between the first end E1 and the first surface WF1 is greater than a distance L12 between the second end E2 and the first surface WF1, and a distance L21 between the first end E1 and the second surface WF2 is smaller than a distance L22 between the second end E2 and the second surface WF2.

[0117] In such a first printing operation, even when the first surface WF1 is printed over a range including the corner WC or its vicinity, the second surface WF2 always becomes the back side of the first surface WF1 when viewed from the first nozzle array L1 or the second nozzle array L2 in the direction of the first ejection vector VD1. Therefore, it is possible to prevent or reduce the ink ejected from the first nozzle array L1 or the second nozzle array L2 from adhering to the second surface WF2 when printing on the first surface WF1. As a result, it is possible to print on the first surface WF1 over a range including the corner WC or its vicinity while reducing the situation where the second surface WF2 is stained with unnecessary ink. In addition, by reducing the ink adhering to the second surface WF2 when printing on the first surface WF1, it is also possible to easily improve the image quality of the printing on the second surface WF2 described later.

[0118] Here, if Figure 7 As shown, the control device 600 controls the driving of the robot arm 200 in the first printing operation so that A2≤WG×tanθ1 is satisfied when the distance between the second end E2 and the first nozzle array L1 or the second nozzle array L2 is set to A2, the distance between the first nozzle array L1 and the first surface WF1 or the distance between the second nozzle array L2 and the first surface WF1 in the normal direction of the nozzle surface F is set to WG, and the angle between the normal direction of the nozzle surface F and the first surface WF1 is set to θ1°. Therefore, the second end E2 of the liquid ejection head 310 located at the position closest to the first surface WF1 is prevented from contacting the first surface WF1 during the first printing operation.

[0119] In addition, if Figure 7 As shown in FIG. 1 , when the angle between the first surface WF1 and the second surface WF2 is θc°, in the first printing operation, the angle θ1° is smaller than (180-θc)°. Figure 7 In the example shown, since θc is 90°, θ1 is smaller than 90°. That is, θ1 is an acute angle. In this way, by making the angle θ1° smaller than (180-θc)° and becoming an acute angle, in the first printing operation, when viewed from the first nozzle array L1 or the second nozzle array L2 in the direction of the first ejection vector VD1, the second surface WF2 always becomes the back side of the first surface WF1. In addition, when θc is smaller than 90° and when θc is greater than 90°, the angle θ1° is also smaller than (180-θc)° and becomes an acute angle.

[0120] In the present embodiment, the control device 600 moves the liquid ejection head 310 in the first printing operation relative to the workpiece W in a direction close to the second surface WF2. Therefore, when printing on the second surface WF2 is performed after printing on the first surface WF1 as in the present embodiment, the movement path of the liquid ejection head 310 can be shortened compared to the operation of moving the liquid ejection head 310 relative to the workpiece W in a direction away from the second surface WF2.

[0121] On the other hand, Figure 8 As shown, the second printing operation of this embodiment performs printing on the region RE2 of the second surface WF2 by ejecting ink from the liquid ejecting head 310 while moving the liquid ejecting head unit 300 from the position P3 to the position P4 along the second surface WF2.

[0122] Position P4 is a position of the liquid ejection head 310 at which the printing position to be printed by the liquid ejection head 310 is an arbitrary position on the second surface WF2. Position P3 is a position of the liquid ejection head 310 at which the printing position to be printed by the liquid ejection head 310 is at a corner WC or its vicinity, or a position farther from position P4 along the Z1 direction than this position, and a position of the liquid ejection head 310 at which the ink from the liquid ejection head 310 is not ejected onto the second surface WF2 but passes through an imaginary surface extending along the second surface WF2. Therefore, printing can be performed on the second surface WF2 across a range including the corner WC or its vicinity. In the present embodiment, printing is performed on the region RE including the region RE1 and the region RE2 by performing both the first printing operation and the second printing operation. Here, printing can be performed between the region RE1 and the region RE2 without forming a completely unprinted region.

[0123] exist Figure 8 In the example shown, the position P3 is the position of the liquid ejection head 310 where the ink from the liquid ejection head 310 passes through the imaginary plane FV2 extending along the second surface WF2 instead of being ejected onto the second surface WF2. Although the position P3 may be located in the Z1 direction relative to the angle WC when viewed along the X-axis direction, Figure 7 In the example shown, when viewed along the direction of the X-axis, the position P3 is located in the Z2 direction relative to the corner WC. Therefore, in the second printing operation, when viewed in the direction perpendicular to the second surface WF2, that is, along the direction of the X-axis, the paths of the plurality of nozzles N intersect with the corner WC. Therefore, in a state where the ink from the liquid ejection head 310 does not land on the first surface WF1 but passes through the imaginary surface FV2 extending along the first surface WF1, the moving speed of the liquid ejection head 310 can be gradually increased and accelerated, so that there is no need to accelerate during the printing process for the area RE2. Therefore, the variation of the moving speed of the liquid ejection head 310 during the printing process for the area RE2 can be reduced. Reducing this variation has the advantage of easily improving the image quality of the printing for the area RE2.

[0124] In the second printing operation, the control device 600 controls the driving of the robot 200 so that the second ejection vector VD2 has a component DC2 in the direction along the second scanning axis AS2 and toward the first surface WF1. Here, the second scanning axis AS2 is an axis along the scanning direction DS2 of the liquid ejection head 310 relative to the workpiece W in the second printing operation for printing the second surface WF2. Typically, the second scanning axis AS2 is an axis parallel to the second surface WF2. In addition, the second ejection vector VD2 is a normal vector of the nozzle surface F in the second printing operation. In addition, the direction of the second ejection vector VD2 is an example of a second ejection direction as a normal direction of the nozzle surface F in the second printing operation.

[0125] As described above, the control device 600 performs the second printing operation of printing on the second surface WF2 in a state where the nozzle surface F is tilted relative to the second surface WF2. That is, in the second printing operation, the angle θ2 formed by the second scanning axis AS2 and the direction of the second ejection vector VD2 is an acute angle, and the ink is ejected at a position closer to the angle WC than the positions of the plurality of nozzles N in the direction along the second scanning axis AS2.

[0126] Here, if Figure 8 As shown, in the second printing operation, the distance L21 between the first end E1 and the second surface WF2 is smaller than the distance L22 between the second end E2 and the second surface WF2, and the distance L11 between the first end E1 and the first surface WF1 is larger than the distance L12 between the second end E2 and the first surface WF1.

[0127] In such a second printing operation, even when the second surface WF2 is printed over a range including the corner WC or its vicinity, the first surface WF1 always becomes the back side of the second surface WF2 when viewed from the first nozzle array L1 or the second nozzle array L2 in the direction of the second ejection vector VD2. Therefore, it is possible to prevent or reduce the ink ejected from the first nozzle array L1 or the second nozzle array L2 from adhering to the first surface WF1 when printing on the second surface WF2. As a result, it is possible to print on the second surface WF2 over a range including the corner WC or its vicinity while reducing the situation where the first surface WF1 is stained with unnecessary ink. In addition, by reducing the ink adhering to the first surface WF1 when printing on the second surface WF2, it is also possible to easily improve the image quality of the printing on the first surface WF1 as described above.

[0128] In the present embodiment, the control device 600 moves the liquid ejection head 310 relative to the workpiece W in a direction away from the first surface WF1 in the second printing operation. Therefore, in the case where the printing of the second surface WF2 is performed after the printing of the first surface WF1 as in the present embodiment, the first surface WF1 and the second surface WF2 can be printed by continuously moving the liquid ejection head 310 along the first surface WF1 and the second surface WF2 in sequence. Therefore, compared with the operation of relatively moving the liquid ejection head 310 relative to the workpiece W in a direction close to the first surface WF1, the moving path of the liquid ejection head 310 can be shortened. In addition, in the present embodiment, the position of the liquid ejection head 310 is moved from position P2 to position P3 after the first printing operation and before the second printing operation. At this time, the posture of the liquid ejection head 310 is changed in the manner described above.

[0129] In this embodiment, the control device 600 adjusts the angle between the first scanning axis AS1 and the first ejection vector VD1 or the first scanning axis AS1 and the second ejection vector VD2 so that the angle θ1 between the first scanning axis AS1 and the first ejection vector VD1 and the angle θ2 between the second scanning axis AS2 and the second ejection vector VD2 are equal to each other. That is, the inclination angle θa of the nozzle surface F relative to the first surface WF1 in the first printing operation and the inclination angle θb of the nozzle surface F relative to the second surface WF2 in the second printing operation are equal to each other. Therefore, printing can be performed under the same or similar conditions in the first printing operation and the second printing operation, so that the adjustment of image quality and the like is relatively easy.

[0130] 2. Second Implementation

[0131] In the following exemplary embodiments, elements having the same functions or effects as those of the first embodiment are denoted by the same reference numerals as those used in the first embodiment, and detailed descriptions thereof are appropriately omitted.

[0132] Fig. 9 This is a diagram for explaining the first printing operation in the second embodiment. Fig.10 This is a diagram for explaining the second printing operation in the second embodiment. This embodiment is the same as the first embodiment described above except that the posture of the liquid ejection head 310 in the second printing operation is different and a recovery mechanism 800 is provided.

[0133] In this embodiment, during the period between the first printing operation and the second printing operation, the posture of the liquid ejection head 310 is rotated 180° around the central axis along the normal line of the nozzle surface F. Therefore, Fig.10The posture of the liquid ejection head 310 in the second printing operation shown is relative to Fig. 9 The posture of the liquid ejection head 310 in the first printing operation shown differs by 180° around the central axis.

[0134] As described above, the control device 600 sets the first end E1 to a position closer to the second surface WF2 than the second end E2 in the first printing operation. In addition, the control device 600 sets the first end E1 to a position closer to the first surface WF1 than the second end E2 in the second printing operation. In this way, by making the posture of the liquid ejection head 310 different around the central axis along the normal line of the nozzle surface F in the first printing operation and the second printing operation, the distance WG can be shortened when there is a structure such as a displacement sensor 330 near the first end E1 of the liquid ejection head 310. Therefore, it is easy to improve the printing quality in both the first printing operation and the second printing operation. In contrast, when the second end E2 is set to a position closer to the second surface WF2 than the first end E1 in the first printing operation, the distance WG needs to be extended to prevent the displacement sensor 330 from contacting the first surface WF1. Likewise, when the second end E2 is positioned closer to the first surface WF1 than the first end E1 in the second printing operation, the distance WG needs to be extended to prevent the displacement sensor 330 from contacting the second surface WF2 .

[0135] The recovery mechanism 800 is a mechanism for recovering ink droplets that float without landing on the surface of the workpiece W, among the ink ejected from the liquid ejection head 310. Fig. 9 as well as Fig.10 In the example shown, the recovery mechanism 800 has a pipe 810 for sucking the ink droplets. A suction mechanism (not shown) is connected to the pipe 810, and the suction mechanism generates an airflow to suck the ink droplets into the pipe 810. In addition, the shape of the pipe 810 is not limited to Fig. 9 as well as Fig.10 In addition, the structure of the recovery mechanism 800 only needs to be able to recover the ink droplets, and is not limited to a structure that sucks the ink into the pipe 810. For example, it can be a structure that uses an adsorption component that adsorbs by an adsorption force such as electrostatic force, or a structure that uses a component that only attaches and absorbs the ink droplets.

[0136] like Fig. 9As shown, in the first printing operation, the duct 810 is arranged along the second surface WF2 to recover the ink droplets that are not sprayed on the first surface WF1 but float over the imaginary surface FV1. In this way, by using the recovery mechanism 800 to recover the ink droplets that are not sprayed on the workpiece W but are scattered, it is not only more difficult for the ink droplets in the first printing operation to adhere to the second surface WF2, but also prevents unnecessary ink droplets from adhering to various parts or peripheral parts of the three-dimensional object printing device 100. Similarly, as Fig.10 As shown, in the second printing operation, the duct 810 is arranged along the first surface WF1 to recover ink droplets that do not land on the second surface WF2 but float over the imaginary surface FV2.

[0137] Here, the recovery mechanism 800 is movable, and the position and posture of the pipe 810 in the first printing operation are different from the position and posture of the pipe 810 in the second printing operation. In this way, by moving the recovery mechanism 800 according to the printing area formed by the liquid ejection head 310, it is possible to effectively recover the ink droplets that are not sprayed on the workpiece W but scattered by using the recovery mechanism 800 while preventing the recovery mechanism 800 from being enlarged. The movement of the recovery mechanism 800 is not particularly limited, for example, it can be implemented by fixing the pipe 810 to the liquid ejection head 310, or by using a mechanism such as an actuator that moves the pipe 810 by a mechanism different from the robot 200. In addition, the position or posture of the recovery mechanism 800 can also be changed in the first printing operation or the second printing operation according to the change in the position or posture of the liquid ejection head 310.

[0138] 3. Third Implementation

[0139] In the following exemplary embodiments, elements having the same functions or effects as those of the first embodiment are given the same reference numerals as those used in the first embodiment, and detailed descriptions thereof are appropriately omitted.

[0140] Fig.11 1 is a diagram for explaining the third printing operation of the third embodiment. In this embodiment, except that printing on the first face WF1 is performed using not only the first printing operation but also the third printing operation, everything is the same as the first embodiment described above.

[0141] like Fig.11 As shown, in the third printing operation, the liquid ejection head unit 300 is moved from the position P0 to the position P1a along the first surface WF1 to eject ink from the liquid ejection head 310 , thereby performing printing on the area RE1 including the area of ​​the first surface WF1 .

[0142] Position P0 is a position farther from second surface WF2 than position P1a. Position P1a is a position that overlaps position P1 when viewed from above with respect to first surface WF1 and is farther from first surface WF1 than position P1.

[0143] In the third printing operation, the control device 600 controls the driving of the robot arm 200 so that the nozzle plane F is parallel to the first plane WF1. Fig.11 , a scanning direction DS3 is illustrated as an example of a moving direction of the liquid ejection head 310 relative to the workpiece W in the third printing operation.

[0144] As described above, the control device 600 performs the third printing operation for printing on the first surface WF1 without tilting the nozzle surface F relative to the first surface WF1. In the third printing operation, the distance L11 between the first end E1 and the first surface WF1 and the distance L12 between the second end E2 and the first surface WF1 are equal. That is, in the third printing operation, the third ejection vector VD3, which is the normal vector of the nozzle surface F, and the normal vector of the first surface WF1 are parallel to or consistent with each other. Therefore, in the third printing operation, since the direction of the ink ejected from the liquid ejection head 310 is orthogonal to the first surface WF1, it is easy to improve the printing quality even if the printing speed is increased compared to the first printing operation. Therefore, by using the first printing operation and the third printing operation at the same time, it is possible to perform high-quality printing on the first surface WF1 at high speed across a range including the corner WC.

[0145] Furthermore, when the distance D between the liquid ejection head 310 and the second surface WF2 is greater than or equal to the predetermined distance Dth when printing is performed on the first surface WF1, the control device 600 performs the third printing operation. Furthermore, when the distance D is less than the predetermined distance Dth, the control device 600 performs the first printing operation. In this way, the first printing operation and the third printing operation are switched according to whether the distance D is greater than or equal to the predetermined distance Dth, so that the first printing operation and the third printing operation can be continuously performed.

[0146] Here, it is preferred to reduce the difference between the distance WG in the first printing operation and the distance WG in the third printing operation, and it is more preferred to make the distance WG in the first printing operation and the distance WG in the third printing operation equal to each other. In this case, compared with a case where this is not the case, it is easy to make the image quality and the like consistent in the first printing operation and the third printing operation.

[0147] exist Fig.11In the example shown, the posture of the liquid ejection head 310 and the distance WG are changed at a position where the distance D becomes the predetermined distance Dth. However, in the first printing operation, the posture of the liquid ejection head 310 and the distance WG may be changed continuously or stepwise at a position where the distance D is smaller than the predetermined distance Dth.

[0148] In addition, although the third printing operation is illustrated in the present embodiment as printing on the first surface WF1, the second surface WF2 may be printed without tilting the nozzle surface F relative to the second surface WF2. In this case, the normal vector of the nozzle surface F and the normal vector of the second surface WF2 are parallel to or coincide with each other. In this case, the second printing operation and the third printing operation are switched according to the distance between the liquid ejection head 310 and the first surface WF1.

[0149] 4. Modifications

[0150] The above-mentioned methods can be modified in various ways. In the following, specific modified methods applicable to the above-mentioned methods are illustrated. In addition, two or more methods arbitrarily selected from the following examples can be appropriately combined within the scope of non-contradiction.

[0151] 4-1. Modification 1

[0152] Fig.12 A diagram for explaining the first printing operation in Modification 1. Fig.13 2 is a diagram for explaining the second printing operation in Modification 1. Modification 1 is the same as the first embodiment except that the moving direction of the liquid ejection head 310 is opposite to that of the first embodiment.

[0153] In variation 1, if Fig.12 As shown, the control device 600 moves the liquid ejection head 310 relative to the workpiece W in the direction away from the second surface WF2, that is, in the X2 direction, during the first printing operation. Fig.13 As shown, the control device 600 moves the liquid ejection head 310 in the direction close to the first surface WF1, that is, the X1 direction, relative to the workpiece W in the second printing operation. When the first printing operation is performed after the second printing operation, the liquid ejection head 310 is moved in such a direction, so that the first surface WF1 and the second surface WF2 can be printed continuously. The above modification 1 can also obtain the same effect as the first embodiment described above.

[0154] In addition, in the second to third embodiments, the moving direction of the liquid ejection head 310 in each of the first printing operation, the second printing operation, and the angle adjustment operation may be set to the direction opposite to the above-described direction.

[0155] In addition, the first printing action in variant example 1 and the second printing action in the first embodiment may be combined, and the first printing action in the first embodiment and the second printing action in variant example 1 may be combined. Furthermore, the rotation action of any one of the second to fourth embodiments or the third printing action may be appropriately combined with any of the above combinations.

[0156] 4-2. Modification 2

[0157] Although the above-mentioned method illustrates the case where the first surface and the second surface are expanded in mutually orthogonal directions, the first surface and the second surface are not limited to this case. For example, they only need to be expanded in mutually intersecting directions within a range of 45° to 135°, preferably within a range of 60° to 120°. In addition, although the above-mentioned method illustrates the case where the first surface and the second surface are each a plane, it is not limited to this. For example, the first surface or the second surface can be bent or curved smoothly as a whole, or fine concave and convex can be provided on the first surface or the second surface. The height of the convex part or the depth of the concave part in the concave and convex is, for example, smaller than the distance WG described above. The first surface or the second surface having the concave and convex can also be understood as a surface that is approximately flat.

[0158] When the first surface or the second surface is gently curved or bent, in order to keep the distance WG constant, the movement of the liquid ejection head 310 in the first printing operation and the second printing operation adopts a trajectory that is curved or bent according to the curvature or curvature of the first surface or the second surface. In this case, the first scanning axis and the second scanning axis can be understood as axes along the direction in which the sum of the movement amounts in the curved or bent trajectory is the largest.

[0159] 4-3. Modification 3

[0160] Although the structure of a vertical multi-axis robot using six axes is illustrated as a moving mechanism in the above-described method, it is not limited to this structure. The moving mechanism only needs to be able to change the relative position and posture of the liquid ejection head relative to the workpiece in three dimensions. Therefore, the moving mechanism may be, for example, a vertical multi-axis robot other than a six-axis robot, or a horizontal multi-axis robot. In addition, the movable part of the robot is not limited to a rotating mechanism, and may be, for example, a telescopic mechanism, etc. In addition, although the moving mechanism of the structure that moves the liquid ejection head is illustrated in the above-described method, it is not limited to this structure, and may be, for example, a structure in which the position of the liquid ejection head is fixed, and the moving mechanism moves the workpiece, thereby changing the relative position and posture of the workpiece in three dimensions relative to the liquid ejection head.

[0161] 4-4. Modification 4

[0162] In the above-described embodiment, a configuration in which printing is performed using one type of ink is exemplified. However, the present invention is not limited to this configuration, and can be applied to a configuration in which printing is performed using two or more types of inks.

[0163] 4-5. Modification 5

[0164] The use of the 3D printing device of the present invention is not limited to printing. For example, the 3D printing device that ejects a solution of a color material is used as a manufacturing device for forming a color filter of a liquid crystal display device. In addition, the 3D printing device that ejects a solution of a conductive material is used as a manufacturing device for forming wiring or electrodes of a wiring substrate.

[0165] Explanation of symbols

[0166] 100…3D printing device; 200…robot arm (moving mechanism); 310…liquid ejection head; 330…displacement sensor; 800…recovery mechanism; 810…pipeline; AS1…first scanning axis; AS2…second scanning axis; D…distance; DC1…component; DC2…component; DS1…scanning direction; DS2…scanning direction; DS3…scanning direction; Dth…predetermined distance; E1…first end; E2…second end; F…nozzle surface; FV1…imaginary surface; FV2…imaginary surface Surface; L1…first nozzle row; L11…distance; L12…distance; L2…second nozzle row; L21…distance; L22…distance; N…nozzle; RE…area; RE1…area; RE2…area; VD1…first ejection vector; VD2…second ejection vector; VD3…third ejection vector; W…workpiece; WC…angle; WF1…first surface; WF2…second surface; WG…distance; θ1…angle; θ2…angle; θa…inclination angle; θb…inclination angle; θc…angle.

Claims

1. A three-dimensional object printing device, characterized in that: have: a liquid ejection head having a nozzle face provided with a plurality of nozzles for ejecting liquid; a moving mechanism that changes the relative position and posture of the liquid ejection head with respect to a workpiece, wherein the workpiece has a first surface and a second surface that forms a curved or convex angle with the first surface, When the axis along the scanning direction of the liquid ejection head relative to the workpiece in the first printing operation for printing on the first surface is set as the first scanning axis, and the normal vector of the nozzle surface in the first printing operation is set as the first ejection vector, The first ejection vector has a component in a direction along the first scanning axis toward the second surface. When printing is performed on the first side, When the distance between the liquid ejection head and the second surface is greater than a predetermined distance, a third printing operation is performed, wherein the third printing operation is an operation of printing on the first surface or the second surface in a state where the normal vector of the nozzle surface and the normal vector of the first surface, or the normal vector of the nozzle surface and the normal vector of the second surface are parallel to or consistent with each other, When the distance between the liquid ejection head and the second surface is less than a predetermined distance, the first printing action is performed.

2. The three-dimensional object printing device according to claim 1, characterized in that: In the first printing operation, when viewed in a direction perpendicular to the first surface, a path along which the plurality of nozzles move along the first scanning axis intersects the corner.

3. The three-dimensional object printing device according to claim 1 or 2, characterized in that: In the first printing operation, the liquid ejection head moves relative to the workpiece in a direction approaching the second surface.

4. The three-dimensional object printing device according to claim 1 or 2, characterized in that: In the first printing operation, the liquid ejection head moves relative to the workpiece in a direction away from the second surface.

5. The three-dimensional object printing device according to claim 1, wherein: When the axis along the scanning direction of the liquid ejection head relative to the workpiece in the second printing operation for printing on the second surface is set as the second scanning axis, and the normal vector of the nozzle surface in the second printing operation is set as the second ejection vector, The second ejection vector has a component in a direction along the second scanning axis and toward the first surface.

6. The three-dimensional object printing device according to claim 5, characterized in that: In the second printing operation, when viewed in a direction perpendicular to the second surface, a path along which the plurality of nozzles move along the second scanning axis intersects the corner.

7. The three-dimensional object printing device according to claim 5, characterized in that: The nozzle surface has a nozzle row composed of a plurality of arranged nozzles, a first end in a direction intersecting with the arrangement direction of the plurality of nozzles, and a second end opposite to the first end. In the first printing operation, the first end is located closer to the second surface than the second end. In the second printing operation, the first end is located closer to the first surface than the second end.

8. The three-dimensional object printing device according to claim 5, characterized in that: An angle formed by the first scanning axis and the first ejection vector and an angle formed by the second scanning axis and the second ejection vector are equal to each other.

9. The three-dimensional object printing device according to claim 1, wherein: The nozzle surface has a nozzle row composed of a plurality of arranged nozzles, a first end in a direction intersecting with the arrangement direction of the plurality of nozzles, and a second end opposite to the first end. In the first printing operation, When the first end is set to a position closer to the second surface than the second end, the distance between the second end and the nozzle array is set to A2, the distance between the nozzle array and the first surface in the normal direction of the nozzle surface is set to WG, and the angle between the normal direction of the nozzle surface and the first surface is set to θ1, Satisfies A2≤WG×tanθ1.

10. A three-dimensional object printing device, characterized in that: have: a liquid ejection head having a nozzle face provided with a plurality of nozzles for ejecting liquid; a moving mechanism that changes the relative position and posture of the liquid ejection head with respect to a workpiece, wherein the workpiece has a first surface and a second surface that forms a curved or convex angle with the first surface, The nozzle surface has a nozzle row composed of a plurality of arranged nozzles, a first end in a direction intersecting with the arrangement direction of the plurality of nozzles, and a second end opposite to the first end. The three-dimensional object printing device performs a first printing operation, wherein the first printing operation is an operation of printing on the first surface while the nozzle surface is tilted relative to the first surface in such a manner that a distance between the first end and the first surface is greater than a distance between the second end and the first surface, and a distance between the first end and the second surface is less than a distance between the second end and the second surface. When printing is performed on the first side, When the distance between the liquid ejection head and the second surface is greater than a predetermined distance, a third printing operation is performed, wherein the third printing operation is an operation of printing on the first surface or the second surface in a state where the normal vector of the nozzle surface and the normal vector of the first surface, or the normal vector of the nozzle surface and the normal vector of the second surface are parallel to or consistent with each other, When the distance between the liquid ejection head and the second surface is less than a predetermined distance, the first printing action is performed.

11. A three-dimensional object printing device, characterized in that: have: a liquid ejection head having a nozzle face provided with a plurality of nozzles for ejecting liquid; a moving mechanism that changes the relative position and posture of the liquid ejection head with respect to a workpiece, wherein the workpiece has a first surface and a second surface that forms a curved or convex angle with the first surface, The nozzle surface has a nozzle row composed of a plurality of arranged nozzles, a first end in a direction intersecting with the arrangement direction of the plurality of nozzles, and a second end opposite to the first end. When an axis along a scanning direction of the liquid ejection head relative to the workpiece in a first printing operation for printing on the first surface is set as a first scanning axis, and a normal direction of the nozzle surface in the first printing operation is set as a first ejection direction, In the first printing operation, the angle formed by the first scanning axis and the first ejection direction is an acute angle, and the liquid is ejected at a position closer to the angle than the positions of the plurality of nozzles in the direction along the first scanning axis. When printing is performed on the first side, When the distance between the liquid ejection head and the second surface is greater than a predetermined distance, a third printing operation is performed, wherein the third printing operation is an operation of printing on the first surface or the second surface in a state where the normal vector of the nozzle surface and the normal vector of the first surface, or the normal vector of the nozzle surface and the normal vector of the second surface are parallel to or consistent with each other, When the distance between the liquid ejection head and the second surface is less than a predetermined distance, the first printing action is performed.

12. The three-dimensional object printing device according to claim 10 or 11, characterized in that: The three-dimensional object printing device performs a second printing action, which is an action of printing on the second surface with the nozzle surface tilted relative to the second surface in such a manner that the distance between the first end and the second surface is smaller than the distance between the second end and the second surface, and the distance between the first end and the first surface is larger than the distance between the second end and the first surface.

13. A three-dimensional object printing method, characterized in that: Printing is performed on a workpiece using a liquid ejection head, the liquid ejection head having a nozzle face provided with a plurality of nozzles for ejecting liquid, the workpiece having a first face and a second face forming a curved or convex angle with the first face, In the three-dimensional object printing method, When the axis along the scanning direction of the liquid ejection head relative to the workpiece in the first printing operation for printing on the first surface is set as the first scanning axis, and the normal vector of the nozzle surface in the first printing operation is set as the first ejection vector, The first ejection vector has a component in a direction along the first scanning axis toward the second surface. When printing is performed on the first side, When the distance between the liquid ejection head and the second surface is greater than a predetermined distance, a third printing operation is performed, wherein the third printing operation is an operation of printing on the first surface or the second surface in a state where the normal vector of the nozzle surface and the normal vector of the first surface, or the normal vector of the nozzle surface and the normal vector of the second surface are parallel to or consistent with each other, When the distance between the liquid ejection head and the second surface is less than a predetermined distance, the first printing action is performed.

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