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

Abstract

To provide a three-dimensional object printer which enables each of a print head and other components to function and prevents these components from contacting with a workpiece as much as possible when a print is made on a three-dimensional object, and to provide a three-dimensional object print method.SOLUTION: A three-dimensional object printer includes: a head unit 300 including a head 310 which includes a discharge surface F1 provided with nozzles N and discharges an ink from the nozzles N to a three-dimentional workpiece, and an energy emission part 330 including an emission surface F2 which emits energy capable of curing the ink; and a robot which changes relative positions and attitudes of the workpiece and the head unit 300. When a direction in which the head 310 discharges the ink is referred to as a discharge direction, the discharge surface F1 is located at the discharge direction side relative to the emission surface F2.SELECTED DRAWING: Figure 3

Description

[Technical field]

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

[0002] There is known a three-dimensional object printing device that performs printing on the surface of a three-dimensional object by an inkjet method. For example, a system described in Patent Document 1 has a robot and a print head arranged on the robot, and ejects ink droplets from the print head onto the curved surface of a vehicle.

[0003] Patent Document 1 describes a method in which a curing head, which is disposed on a robot adjacent to the print head, is caused to trace in the same direction as the print head, thereby curing the ink immediately after printing. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 2015-520011 Summary of the Invention [Problem to be solved by the invention]

[0005] However, if the curing head is arranged around the print head, there is a risk that the curing head will come into contact with the work when the print head is adjusted to a desired position and posture with respect to the three-dimensional workpiece to be printed. Thus, while it is necessary to provide components such as the curing head and the distance measuring means that act on the workpiece or are acted on by the workpiece near the print head, it is desirable that each of them function and prevent contact with the workpiece as much as possible. From the above-mentioned viewpoints, it has been one of the challenges to appropriately arrange components such as the curing head and the distance measuring means around the print head. [Means for solving the problem]

[0006] The three-dimensional object printing device has a head unit including a head having an ejection surface with a nozzle and ejecting liquid from the nozzle onto a three-dimensional workpiece, and a hardening means having an exit surface that emits energy capable of hardening the liquid, and a moving mechanism that changes the relative position and attitude of the workpiece and the head unit, and when the direction in which the head ejects the liquid is defined as the ejection direction, the ejection surface is located on the ejection direction side of the exit surface.

[0007] The three-dimensional object printing device has a head unit including a head having an ejection surface with nozzles and ejecting liquid from the nozzles onto a three-dimensional workpiece, and a distance measurement means having a measurement surface for measuring the relative distance from the workpiece, and a moving mechanism for changing the relative position and attitude of the workpiece and the head unit, and when the direction in which the head ejects the liquid is defined as the ejection direction, the ejection surface is located on the ejection direction side of the measurement surface.

[0008] The three-dimensional printing method involves printing on a printing area of ​​a work using a head unit that includes a head having an ejection surface with a nozzle and that ejects liquid from the nozzle onto a three-dimensional workpiece, and a curing means having an exit surface that emits energy capable of hardening the liquid, wherein when the direction in which the head ejects the liquid is defined as the ejection direction, the ejection surface is located on the ejection direction side of the exit surface, the workpiece has a protrusion that protrudes toward the head unit at a position different from the printing area, and when the ejection surface is opposed to the printing area and the liquid is ejected from the head, the exit surface overlaps with the protrusion when viewed in the ejection direction. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a perspective view showing an outline of a three-dimensional object printing device and a workpiece according to a first embodiment. [Diagram 2] FIG. 2 is a block diagram showing the electrical configuration of the three-dimensional object printing device according to the first embodiment. [Diagram 3] FIG. 2 is a perspective view showing a configuration of a head unit in the first embodiment. [Figure 4] FIG. 2 is a plan view showing the configuration of a head unit in the first embodiment. [Diagram 5] 4 is a side view showing the positional relationship between a head unit and an arm in the first embodiment. FIG. [Figure 6] 4 is a flowchart showing the flow of a three-dimensional object printing method according to the first embodiment. [Figure 7A] FIG. 4 is a side view for explaining path setting and printing operation in the first embodiment. [Figure 7B] FIG. 4 is a side view for explaining path setting and printing operation in the first embodiment. [Figure 7C] FIG. 4 is a side view for explaining path setting and printing operation in the first embodiment. [Figure 8] FIG. 11 is a perspective view showing an outline of a three-dimensional object printing device and a workpiece according to a second embodiment. [Figure 9] FIG. 11 is a plan view for explaining path setting and printing operation in the second embodiment. [Figure 10] 13A and 13B are side views for explaining path setting and printing operations in the third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. Note that the dimensions or scale of each part in the drawings may differ from the actual dimensions, and some parts are shown diagrammatically to facilitate understanding. Furthermore, the scope of the present invention is not limited to these embodiments unless otherwise specified in the following description to the effect that the present invention is limited thereto.

[0011] In the following description, the mutually intersecting X-axis, Y-axis, and Z-axis are used as appropriate. Furthermore, one 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, the opposite directions along the Y-axis are referred to as the Y1 direction and the Y2 direction. Furthermore, the opposite directions along the Z-axis are referred to as the Z1 direction and the Z2 direction.

[0012] Here, the X-axis, Y-axis, and Z-axis are coordinate axes of a base coordinate system set in a space in which the workpiece W and base 210 described later are installed. Typically, the Z-axis is a vertical axis, and the Z2 direction corresponds to the downward direction in the vertical direction. Note that the Z-axis does not have to be a vertical axis. Also, the X-axis, Y-axis, and Z-axis are typically mutually orthogonal, but are not limited to this, and may not be orthogonal. For example, the X-axis, Y-axis, and Z-axis may intersect each other at an angle within a range of 80° to 100°.

[0013] 1. First embodiment 1-1. Overview of the three-dimensional printing device 1 is a perspective view showing an outline of a three-dimensional object printing apparatus 100 according to an embodiment of the present invention. The three-dimensional object printing apparatus 100 is an apparatus that performs printing on the surface of a three-dimensional workpiece W by an inkjet method.

[0014] The workpiece W has a surface WF to be printed. In the example shown in Fig. 1, the surface WF is a concave curved surface having multiple portions with different curvatures. The size, shape, and installation posture of the workpiece W are not limited to the example shown in Fig. 1 and are arbitrary.

[0015] In the example shown in Fig. 1, the three-dimensional object printing apparatus 100 is an inkjet printer that uses a vertical articulated robot. Specifically, as shown in Fig. 1, the three-dimensional object printing apparatus 100 has a robot 200, a head unit 300, a liquid supply unit 400, and a controller 600. Below, first, each part of the three-dimensional object printing apparatus 100 shown in Fig. 1 will be briefly described in order.

[0016] The robot 200 is a moving mechanism that changes the relative position and posture of the workpiece W and the head unit 300. In the example shown in Fig. 1, the robot 200 is a so-called six-axis vertical articulated robot. Specifically, the robot 200 has a base 210 and an arm 220.

[0017] The base 210 is a platform that supports the arm 220. In the example shown in Fig. 1, the base 210 is fixed to an installation surface such as a floor surface facing the Z1 direction by means of screws or the like. The installation surface to which the base 210 is fixed may be a surface facing any direction and is not limited to the example shown in Fig. 1, and may be, for example, a wall, a ceiling, a surface of a movable dolly, or the like.

[0018] Arm 220 is a six-axis robot arm having a base end attached to base 210 and a tip end that changes its position and posture three-dimensionally relative to the base end. Specifically, arm 220 has arms 221, 222, 223, 224, 225, and 226, which are connected in this order.

[0019] The arm 221 is connected to the base 210 via a joint 230_1 so as to be rotatable around a first rotation axis O1. The arm 222 is connected to the arm 221 via a joint 230_2 so as to be rotatable around a second rotation axis O2. The arm 223 is connected to the arm 222 via a joint 230_3 so as to be rotatable around a third rotation axis O3. The arm 224 is connected to the arm 223 via a joint 230_4 so as to be rotatable around a fourth rotation axis O4. The arm 225 is connected to the arm 224 via a joint 230_5 so as to be rotatable around a fifth rotation axis O5. The arm 226 is connected to the arm 225 via a joint 230_6 so as to be rotatable around a sixth rotation axis O6. In the following, each of the joints 230_1 to 230_6 may be referred to as a joint 230.

[0020] The joint 230 is an example of a "movable part". FIG. 1 illustrates an example in which the number of the joints 230 is six. In the example illustrated in FIG. 1, each of the joints 230_1 to 230_6 is a mechanism that rotatably connects one of two adjacent arms to the other. Although not illustrated in FIG. 1, each of the joints 230_1 to 230_6 is provided with a drive mechanism that rotates one of the two adjacent arms to the other. The drive mechanism includes, for example, a motor that generates a drive force for the rotation, a reducer that reduces the speed of the drive force and outputs it, and an encoder such as a rotary encoder that measures an amount of movement such as an angle of the rotation. The assembly of the drive mechanisms corresponds to an arm drive mechanism 240 illustrated in FIG. 2 described later. The encoder corresponds to an encoder 241 illustrated in FIG. 2 described later.

[0021] The first rotation axis O1 is an axis perpendicular to an 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.

[0022] With regard to these rotation axes, "perpendicular" refers not only to the case where the angle between the two rotation axes is exactly 90°, but also to the case where the angle between the two rotation axes is offset within a range of about ±5° from 90°. Similarly, "parallel" refers not only to the case where the two rotation axes are exactly parallel, but also to the case where one of the two rotation axes is inclined relative to the other axis within a range of about ±5°.

[0023] A head unit 300 is attached to the tip of the arm 220, that is, to the arm 226, as an end effector.

[0024] The head unit 300 is a device having a head 310 that ejects ink, which is an example of a liquid, toward the workpiece W, an energy emission unit 330 that is a curing means that cures the ink ejected from the head 310 onto the workpiece W, and a distance measurement unit 360 that is a distance measurement means that measures the distance from the head unit 300 to the workpiece W. In this embodiment, the head unit 300 has a pressure adjustment valve 320 that adjusts the pressure of the ink supplied to the head 310, in addition to the head 310, the energy emission unit 330, and the distance measurement unit 360. These are all fixed to the arm 226, so that the relationship between their positions and attitudes is fixed.

[0025] The three-dimensional object printing apparatus 100 uses a vertical articulated robot as a movement mechanism, so that the positional relationship between the head unit 300 and the workpiece W can be set arbitrarily, and printing can be performed on a desired surface of the workpiece W.

[0026] The ink is not particularly limited, and examples thereof include water-based inks in which a coloring material such as a dye or pigment is dissolved in a water-based solvent, curable inks using a curable resin such as an ultraviolet curable type, and solvent-based inks in which a coloring material such as a dye or pigment is dissolved in an organic solvent. Among them, curable inks are preferably used. The curable ink is not particularly limited, and may be, for example, any of a heat curable type, a photocurable type, a radiation curable type, and an electron beam curable type, but a photocurable type such as an ultraviolet curable type is preferable. The ink is not limited to a solution, and may be an ink in which a coloring material or the like is dispersed as a dispersoid in a dispersion medium. The ink is not limited to an ink containing a coloring material, and may be an ink containing conductive particles such as metal particles for forming wiring or the like as a dispersoid.

[0027] Although not shown in FIG. 1, the head 310 has a head chip inside. The head chip has a piezoelectric element, a cavity that contains ink, and a nozzle N that communicates with the cavity. Here, the piezoelectric element is provided for each cavity, and ink is ejected from the nozzle N corresponding to the cavity by changing the pressure of the cavity. Such a head chip is obtained, for example, by bonding a plurality of substrates such as silicon substrates that have been appropriately processed by etching or the like with an adhesive or the like. The nozzle N is formed in a nozzle plate 312 described later. The nozzle plate 312 is one of the substrates that constitute the head chip. The piezoelectric element corresponds to a piezoelectric element 311 shown in FIG. 2 described later. Also, instead of the piezoelectric element, a heater that heats the ink in the cavity may be used as a driving element for ejecting ink from the nozzle N.

[0028] The pressure regulating valve 320 is a valve mechanism that opens and closes according to the pressure of the ink inside the head 310. This opening and closing maintains the pressure of the ink inside the head 310 at a negative pressure within a predetermined range. This stabilizes the meniscus of the ink formed in the nozzle N of the head 310. As a result, it is possible to prevent air bubbles from entering the nozzle N and ink from overflowing from the nozzle N.

[0029] 1, the head unit 300 has one head 310 and one pressure adjustment valve 320, but the numbers are not limited to the example shown in Fig. 1 and may be two or more. In addition, the installation position of the pressure adjustment valve 320 is not limited to the arm 226 and may be, for example, another arm or the like, or may be in a fixed position relative to the base 210.

[0030] The energy emission unit 330 emits energy capable of curing the ink, such as light, heat, an electron beam, or radiation, depending on the type of ink. For example, if the ink is ultraviolet-curable, the energy is ultraviolet. The energy emission unit 330 has a configuration according to the type of energy. For example, if the energy is ultraviolet, the energy emission unit 330 includes a light source such as a light-emitting element, such as an LED (light emitting diode), that emits ultraviolet light. The energy emission unit 330 may have optical components, such as a lens, for adjusting the emission direction or emission range of the energy.

[0031] The ink is cured by irradiation with energy emitted from the energy emission unit 330. Here, "curing" is a concept that includes the curing of a curable resin such as a thermosetting resin or a photocurable resin by a reaction such as a polymerization reaction, obtaining a solid derived from a solute by removing a solvent from a solution, or obtaining a solid derived from a dispersoid by removing a dispersion medium from a dispersion liquid.

[0032] Here, it is preferable that the intensity of the energy emitted by the energy emission unit 330 is adjustable. In this case, nozzle clogging can be reduced by reducing the intensity of the energy during the printing operation described below, and the time required for curing or solidifying the ink can be shortened by increasing the intensity of the energy during the curing operation described below.

[0033] The distance measurement unit 360 measures the distance between the distance measurement unit 360 and the workpiece W by emitting electromagnetic waves, sound waves, or the like to the workpiece W and detecting the electromagnetic waves or sound waves reflected by the workpiece W. For example, a laser displacement meter or an ultrasonic sensor can be used as the distance measurement unit 360. Another example of the distance measurement unit 360 may be a three-dimensional vision camera.

[0034] The liquid supply unit 400 is a mechanism for supplying ink to the head 310. The liquid supply unit 400 has a liquid storage section 410 and a supply flow path 420.

[0035] The liquid storage unit 410 is a container that stores ink. The liquid storage unit 410 is, for example, a bag-shaped ink pack made of a flexible film.

[0036] 1, the liquid storage unit 410 is fixed to a wall, ceiling, pillar, or the like so that it is always located further in the Z1 direction than the head 310. In other words, the liquid storage unit 410 is located vertically above the movement area of ​​the head 310. For this reason, ink can be supplied from the liquid storage unit 410 to the head 310 with a predetermined pressure without using a mechanism such as a pump.

[0037] The supply flow path 420 is a flow path that supplies ink from the liquid storage section 410 to the head 310. A pressure adjustment valve 320 is provided in the middle of the supply flow path 420. Therefore, even if the positional relationship between the head 310 and the liquid storage section 410 changes, it is possible to reduce fluctuations in the pressure of the ink inside the head 310.

[0038] The controller 600 is a robot controller that controls the driving of the robot 200. The functions of the controller 600 and the connection relationship between the controller 600 and other components not shown in FIG.

[0039] 1-2. Electrical configuration of the 3D printing device FIG. 2 is a block diagram showing an electrical configuration of the three-dimensional object printing apparatus 100 according to the first embodiment. FIG. 2 shows electrical components among the components of the three-dimensional object printing apparatus 100. FIG. 2 also shows an arm driving mechanism 240 including encoders 241_1 to 241_6. The arm driving mechanism 240 is an assembly of the above-mentioned driving mechanisms that operate the joints 230_1 to 230_6. The encoders 241_1 to 241_6 are provided corresponding to the joints 230_1 to 230_6, and measure the movement amounts, such as the rotation angles, of the joints 230_1 to 230_6. In the following, each of the encoders 241_1 to 241_6 may be referred to as the encoder 241.

[0040] As shown in FIG. 2, the three-dimensional object printing device 100 includes the robot 200, head unit 300, and controller 600 described above, as well as a control module 500 and a computer 700. In this embodiment, the computer 700 is communicatively connected to the controller 600 and the control module 500. Furthermore, the controller 600 and the control module 500 are electrically connected without the computer 700, and can directly transmit a signal D3 described later. Note that each electrical component may be appropriately divided, a part of it may be included in another component, or it may be configured integrally with another component.

[0041] The controller 600 has a function of controlling the driving of the robot 200, and a function of generating a signal D3 for synchronizing the ejection operation of the head 310 with the operation of the robot 200. The controller 600 has a memory circuit 610 and a processing circuit 620.

[0042] The memory circuitry 610 stores various programs executed by the processing circuitry 620 and various data processed by the processing circuitry 620.

[0043] The memory circuit 610 stores path information Db. Here, the path information Db is information indicating a path along which the head unit 300 should move. The path information Db is expressed, for example, using coordinate values ​​of a base coordinate system. The path information Db is determined based on work information indicating the position and shape of the work W. The work information is obtained by associating information such as CAD (computer-aided design) data indicating the three-dimensional shape of the work W with the aforementioned base coordinate system. The above path information Db is input from the computer 700 to the memory circuit 610.

[0044] The processing circuit 620 controls the operation of the joints 230_1 to 230_6 based on the path information Db, and generates a signal D3. Specifically, the processing circuit 620 performs an inverse kinematic calculation, which is a calculation for converting the path information Db into the movement amount such as the rotation angle and the rotation speed of each of the joints 230_1 to 230_6. Then, the processing circuit 620 outputs the control signals Sk_1 to Sk_6 based on the outputs D1_1 to D1_6 from the encoders 241_1 to 241_6 included in the arm driving mechanism 240 of the robot 200 so that the movement amount such as the actual rotation angle and the rotation speed of each of the joints 230_1 to 230_6 becomes the above-mentioned calculation result. The control signals Sk_1 to Sk_6 correspond to the joints 230_1 to 230_6, and control the driving of the motors provided in the corresponding joints 230. The outputs D1_1 to D1_6 correspond to the encoders 241_1 to 241_6. Hereinafter, each of the outputs D1_1 to D1_6 may be referred to as output D1.

[0045] Furthermore, the processing circuit 620 generates a signal D3 based on the output D1 from at least one of the encoders 241_1 to 241_6. For example, the processing circuit 620 generates the signal D3 as a trigger signal at the timing when the output D1 from one of the encoders 241_1 to 241_6 becomes a predetermined value.

[0046] The control module 500 is a circuit that controls the ejection operation of the head 310 based on a signal D3 output from the controller 600 and print data Img from the computer 700. The control module 500 has a timing signal generation circuit 510, a power supply circuit 520, a control circuit 530, and a drive signal generation circuit 540.

[0047] The timing signal generating circuit 510 generates a timing signal PTS using the signal D3 as a trigger. The timing signal PTS is a signal that defines the timing of the ejection operation of the head 310, and is generated by a timer included in the timing signal generating circuit 510.

[0048] The power supply circuit 520 receives power from a commercial power supply (not shown) and generates various predetermined potentials. The generated various potentials are appropriately supplied to each section of the three-dimensional object printing device 100. For example, the power supply circuit 520 generates a power supply potential VHV and an offset potential VBS. The offset potential VBS is supplied to the head unit 300. In addition, the power supply potential VHV is supplied to the drive signal generation circuit 540.

[0049] The control circuit 530 generates a control signal SI, a waveform designation signal dCom, a latch signal LAT, a clock signal CLK, and a change signal CNG based on the timing signal PTS. These signals are synchronized with the timing signal PTS. Of these signals, the waveform designation signal dCom is input to the drive signal generation circuit 540, and the other signals are input to the switch circuit 340 of the head unit 300.

[0050] The control signal SI is a digital signal for specifying the operating state of the piezoelectric element 311 of the head 310. The waveform specification signal dCom is a digital signal for defining the waveform of the drive signal Com, which will be described later. The latch signal LAT and the change signal CNG are used in combination with the control signal SI to define the timing of ink ejection from the nozzle N. The clock signal CLK is a reference clock signal synchronized with the timing signal PTS.

[0051] The drive signal generating circuit 540 is a circuit that generates a drive signal Com for driving each piezoelectric element 311 of the head 310. Specifically, the drive signal generating circuit 540 has, for example, a DA conversion circuit and an amplifier circuit. In the drive signal generating circuit 540, the DA conversion circuit converts the waveform designation signal dCom from the control circuit 530 from a digital signal to an analog signal, and the amplifier circuit amplifies the analog signal using the power supply potential VHV from the power supply circuit 520 to generate the drive signal Com. Here, among the waveforms included in the drive signal Com, a signal of a waveform that is actually supplied to the piezoelectric element 311 is a drive pulse PD. The drive pulse PD is supplied from the drive signal generating circuit 540 to the piezoelectric element 311 via the switch circuit 340. The switch circuit 340 switches whether or not 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.

[0052] The computer 700 has a function of supplying path information Db to the controller 600 and a function of supplying print data Img to the control module 500. The computer 700 of this embodiment is electrically connected to the energy output unit 330 described above, and outputs a signal D2 that controls the driving of the energy output unit 330 based on signals from the controller 600 and the control module 500. The computer 700 of this embodiment is electrically connected to the distance measurement unit 360 described above, and the distance measurement unit 360 outputs distance information D4 to the computer 700. The controller 600 and the distance measurement unit 360 may be directly connected. The functions of the energy output unit 330 and the distance measurement unit 360 will be described later.

[0053] 1-3.Head unit FIG. 3 is a perspective view showing a schematic configuration of a head unit 300 in the first embodiment.

[0054] In the following explanation, the mutually intersecting a-axis, b-axis, and c-axis are used as appropriate. Furthermore, one direction along the a-axis is called the a1 direction, and the direction opposite to the a1 direction is called the a2 direction. Similarly, the opposite directions along the b-axis are called the b1 direction and the b2 direction. Furthermore, the opposite directions along the c-axis are called the c1 direction and the c2 direction.

[0055] Here, the a-axis, b-axis, and c-axis are coordinate axes of a tool coordinate system set in the head unit 300, and the relative position and posture relationships with the X-axis, Y-axis, and Z-axis change due to the operation of the robot 200. In the example shown in Fig. 3, the c-axis is an axis parallel to the sixth rotation axis O6. The a-axis, b-axis, and c-axis are typically perpendicular to each other, but are not limited to this, and may intersect at an angle within a range of 80° to 100°, for example.

[0056] As described above, the head unit 300 has the head 310, the pressure regulating valve 320, the energy emission section 330, and the distance measurement section 360. These are supported by a support 350 indicated by a dashed line in FIG.

[0057] The support 350 is made of, for example, a metal material, and is a substantially rigid body. Although the support 350 has a flat box shape in Fig. 3, the shape of the support 350 is not particularly limited and may be any shape.

[0058] The support 350 is attached to the tip of the arm 220, i.e., to the arm 226. Therefore, the positional relationship between the head 310, the pressure regulating valve 320, the energy emitter 330, and the distance measuring unit 360 and the arm 226 is fixed.

[0059] 3, the pressure regulating valve 320 is positioned in the c1 direction relative to the head 310. The energy output unit 330 is positioned in the a2 direction relative to the head 310. The distance measuring unit 360 is positioned in the a1 direction relative to the head 310. The detailed positional relationship between the head 310, the energy output unit 330, and the distance measuring unit 360 will be described later.

[0060] The supply flow path 420 is divided into an upstream flow path 421 and a downstream flow path 422 by the pressure regulating valve 320. That is, the supply flow path 420 has the upstream flow path 421 that connects the liquid storage section 410 and the pressure regulating valve 320, and the downstream flow path 422 that connects the pressure regulating valve 320 and the head 310.

[0061] FIG. 4 is a plan view showing the configuration of head unit 300 in this embodiment when viewed in the c1 direction.

[0062] As shown in Fig. 3 and Fig. 4, in this embodiment, the head 310 includes a nozzle plate 312, a housing part 313, and a cover member 314. The nozzle plate 312 is a plate-shaped member that constitutes a part of the head chip described above, and is made of silicon (Si) or metal, with a plurality of nozzles N opened therein. The housing part 313 is a member that holds the head chip, and is made of resin or metal, and is provided with an internal flow path that supplies ink to the head chip. The cover member 314 is a metallic member that is formed to surround the nozzle plate 312, and protects the nozzle plate 312.

[0063] Here, the head 310 has an ejection surface F1 on which nozzles N are formed. The ejection surface F1 is the surface of the portion constituting the nozzle plate 312 and its periphery, and is a surface that is visible when the head 310 is viewed from the ink ejection direction side. In this embodiment, the ink ejection direction, i.e., the direction in which the head 310 ejects ink, is the c2 direction, and viewing from the ink ejection direction side means viewing the head 310 in the c1 direction. Here, the nozzle plate 312 and its periphery refer to the portion on the c2 direction side where the nozzle plate 312 is provided when the head 310 is divided in half in the c-axis direction.

[0064] The ejection surface F1 may include multiple surfaces. In this embodiment, the ejection surface F1 includes a nozzle surface F11 and a cover surface F12. The nozzle surface F11 is a surface whose normal direction is along the c-axis of the nozzle plate 312, and ink is ejected in the c2 direction from multiple nozzles N provided on the nozzle surface F11. The cover surface F12 is a surface whose normal direction is along the c-axis, and the nozzle surface F11 is provided at an opening provided on the cover surface F12.

[0065] Here, the nozzle surface F11 and the cover surface F12 may be positioned at different positions in the c-axis direction. Although not shown in Fig. 3, the cover surface F12 is positioned slightly toward the c2 direction side of the nozzle surface F11. This positional relationship makes it difficult for objects to come into contact with the nozzle surface F11, and therefore the nozzle surface F11 is protected.

[0066] In this embodiment, the components that configure the ejection surface F1 are the nozzle plate 312 and the cover member 314, but the components that configure the ejection surface F1 are not limited to these. For example, if the housing part 313 is larger than the cover member 314 in the a1 direction or the a2 direction, the part of the housing part 313 that can be seen when viewed in the c1 direction is included in the ejection surface F1.

[0067] The multiple nozzles N are divided into a first nozzle row La and a second nozzle row Lb that are arranged at intervals in the direction along the a-axis. Each of the first nozzle row La and the second nozzle row Lb is an example of a "nozzle row" and is a collection of multiple nozzles N that are linearly arranged in the direction along the b-axis. For this reason, in the following description, the b-axis may be referred to as the nozzle row axis. Here, the elements related to each nozzle N of the first nozzle row La in the head 310 and the elements related to each nozzle N of the second nozzle row Lb are configured to be approximately symmetrical to each other in the direction along the a-axis.

[0068] However, the positions of the multiple nozzles N in the first nozzle row La and the multiple nozzles N in the second nozzle row Lb in the direction along the b-axis may be the same or different. Also, elements related to each nozzle N of one of the first nozzle row La and the second nozzle row Lb may be omitted. In the following, a configuration in which the positions of the multiple nozzles N in the first nozzle row La and the multiple nozzles N in the second nozzle row Lb in the direction along the b-axis are the same will be exemplified.

[0069] The energy output unit 330 includes a window unit 331 and a housing unit 332. The housing unit 332 is a box-shaped member made of metal or the like. The window unit 331 is a member made of transparent glass or the like, and is provided on the surface of the housing unit 332 on the c2 direction side.

[0070] Here, the energy output unit 330 has an output surface F2 from which energy is output. The output surface F2 is a surface that constitutes the window unit 331 and its periphery, and is a surface that is visible when the energy output unit 330 is viewed from the aforementioned ejection direction side. Here, the window unit 331 and its periphery constitute the portion on the c2 direction side where the window unit 331 is provided when the energy output unit 330 is divided in half in the c-axis direction.

[0071] The exit surface F2 may include multiple surfaces. In this embodiment, the exit surface F2 is composed of a window surface F21 and a housing surface F22. The window surface F21 is a surface of the window portion 331 that is exposed to the outside. The housing surface F22 is a surface of the housing portion 332 that is visible when the housing portion 332 is viewed in the c1 direction.

[0072] The energy emission unit 330 in this embodiment is an ultraviolet lamp. A UV-LED (Ultraviolet light emitting diode) and a reflector (not shown) are arranged inside the housing unit 332, and ultraviolet light generated from the UV-LED is emitted in the c2 direction from the window surface F21. In other words, the c2 direction is the energy emission direction. Note that the ultraviolet lamp generates heat when emitting light due to the electrical resistance of the electronic components and wiring provided inside.

[0073] In this embodiment, the window portion 331 is flat, and the normal direction of the window surface F21 is the c2 direction. However, the shape of the window portion 331 is not limited to this. The window portion 331 may have another shape, such as a concave lens shape or a convex lens shape, in which case the window surface F21 is curved. The shape of the housing portion 332 is similarly not limited.

[0074] The window surface F21 and the housing surface F22 may be located at different positions in the c-axis direction. Although not shown in Fig. 3, the housing surface F22 is located slightly toward the c2 direction side of the window surface F21. This positional relationship makes it difficult for objects to come into contact with the window surface F21, and therefore the window surface F21 is protected.

[0075] Distance measurement unit 360 includes a window unit 361 and a housing unit 362. Housing unit 362 is a box-shaped member made of metal, resin, etc. Window unit 361 is a member made of transparent glass, resin, etc., and is provided on the surface of housing unit 362 on the c2 direction side.

[0076] Here, the distance measurement unit 360 has a measurement surface F3 for measuring the relative distance to the workpiece W. The measurement surface F3 is the surface of the portion constituting the window portion 361 and its periphery, and is a surface that is visible when the distance measurement unit 360 is viewed from the above-mentioned discharge direction side. Here, the portion constituting the window portion 361 and its periphery refers to the portion on the c2 direction side where the window portion 361 is provided when the distance measurement unit 360 is divided in half in the c-axis direction.

[0077] The measurement surface F3 may include multiple surfaces. The measurement surface F3 is composed of a window surface F31 and a housing surface F32. The window surface F31 is a surface of the window portion 361 that is exposed to the outside. The housing surface F32 is a surface of the housing portion 362 that is visible when the housing portion 362 is viewed in the c1 direction.

[0078] The distance measuring unit 360 in this embodiment is a laser displacement meter. A laser light source and a light receiving element (not shown) are arranged inside the housing 362. A laser beam generated from the laser light source is emitted from the window 361, reflected by the surface of the object, enters the window 361 again, and is detected by the light receiving element. In this way, the laser displacement meter can measure the distance between the distance measuring unit 360 and the surface of the workpiece W in the direction along the c axis. In other words, the c2 direction is the measurement direction of the distance measuring unit 360. Note that the distance measuring unit 360 generates heat during measurement due to the electrical resistance of the electronic components and wiring provided inside.

[0079] In this embodiment, the window portion 361 is flat, and the normal direction of the window surface F31 is the c2 direction. However, the shape of the window portion 361 is not limited to this. The window portion 361 may have another shape, such as a concave lens shape or a convex lens shape, in which case the window surface F31 is curved. The shape of the housing portion 362 is similarly not limited. Note that a plurality of windows 361 may be provided.

[0080] The window surface F31 and the housing surface F32 may be located at different positions in the c-axis direction. Although not shown in Fig. 3, the housing surface F32 is located slightly toward the c2 direction side of the window surface F31. This positional relationship makes it difficult for an object to come into contact with the window surface F31, and protects the window surface F21.

[0081] Next, the positional relationship between the ejection surface F1 of the head 310, the emission surface F2 of the energy emission unit 330, and the measurement surface F3 of the distance measurement unit 360 will be described.

[0082] 5 is a side view showing the positional relationship between the head unit 300 and the robot 200 according to this embodiment, and shows the head 310, the energy emitter 330, the distance measurement unit 360, and the support 350 when the head unit 300 is viewed in the b-axis direction. As described above, the support 350 of the head unit 300 is attached to the tip of the arm 220 described above, i.e., the arm 226.

[0083] 3 and 5, the ejection surface F1 of the head 310 is located on the c2 direction side of the emission surface F2 of the energy emission unit 330. In other words, the ejection surface F1 is located on the ink ejection direction side of the emission surface F2. In addition, the ejection surface F1 of the head 310 is located on the c2 direction side of the measurement surface F3 of the distance measurement unit 360. In other words, the ejection surface F1 is located on the ink ejection direction side of the measurement surface F3.

[0084] Furthermore, the emission surface F2 is located between the measurement surface F3 and the ejection surface F1 in the c-axis direction. Furthermore, the distance between the emission surface F2 and the ejection surface F1 in the c-axis direction is shorter than the distance between the emission surface F2 and the measurement surface F3 in the c-axis direction.

[0085] In Fig. 5, the fifth rotation axis O5, which is the rotation axis of the joint 230_5 of the arm 220, is in a positional relationship substantially parallel to the nozzle row axis of the head 310 described above. In other words, the fifth rotation axis O5 is parallel to the b-axis. Such a positional relationship between the arm 220 and the head 310 is possible by adjusting the rotation about the sixth rotation axis O6 at the joint 230_6, which rotates the arm 226 relative to the arm 225. Here, in this embodiment, the nozzle row axis is formed along the b-axis, and the rotation axis of the joint 230_6 is parallel to the c-axis.

[0086] As shown in FIG. 5, when the distance between the fifth rotation axis O5 parallel to the nozzle row axis and the end F1a of the ejection surface F1 is R, the emission surface F2 is located inside a virtual circle C with the fifth rotation axis O5 as the center axis and a radius of R. Similarly, the measurement surface F3 is located inside the virtual circle C. Here, the end F1a of the ejection surface F1 refers to the part of the ejection surface F1 that is the furthest from the fifth rotation axis O5 when the head 310 is viewed in the nozzle row axis direction. In other words, when the fifth rotation axis O5 is taken as the starting point, the distance to the end F1a is greater than the distance to the end of the emission surface F2 that is the furthest from the fifth rotation axis O5 and the distance to the end of the measurement surface F3 that is the furthest from the fifth rotation axis O5.

[0087] The energy emitting unit 330 and the distance measuring unit 360 may be arranged so that the emission surface F2 and the measurement surface F3 are located inside the imaginary circle C, and are not limited to the positions shown in Fig. 5. In other words, the position of the energy emitting unit 330 may be adjusted according to the dimensions so that the emission surface F2 is located inside the imaginary circle C, and it may be arranged at the position 330a shown by the dashed line in Fig. 5, for example. The same applies to the distance measuring unit 360.

[0088] The multiple rotation axes of the arm 220 of the robot 200 include at least one rotation axis that can be parallel to the nozzle row axis, and the fifth rotation axis O5 is the rotation axis that is closest to the head unit 300. A rotation axis that satisfies these conditions may be referred to as a central rotation axis below. In other words, the imaginary circle C is formed with the central rotation axis as its central axis. Note that "close" here refers to the order in the connection relationship of the arm 220.

[0089] The energy emitter 330 may be tilted. For example, the energy emitter 330 may be tilted so that the emission surface F2 faces the side opposite to the side where the head 310 is located, as in the posture 330b shown by the dashed line in FIG.

[0090] 4, when the head unit 300 is viewed in the c1 direction, the ejection surface F1 is located between the emission surface F2 and the measurement surface F3 in the a-axis direction, i.e., in the direction perpendicular to both the nozzle row axis and the ejection direction. The width W310 of the ejection surface F1 in the a-axis direction is narrower than the width W330 of the emission surface F2 in the a-axis direction. Furthermore, the width W310 of the ejection surface F1 is narrower than the width W331 of the window surface F21.

[0091] 3, when the head unit 300 is viewed in the c-axis direction, the downstream flow path 422 is located between the energy output unit 330 and the distance measurement unit 360. In other words, the downstream flow path 422 is sandwiched between the energy output unit 330 and the distance measurement unit 360 in the a-axis direction.

[0092] As shown in FIG. 4, when the head unit 300 is viewed in the c1 direction, the end of the b1 direction of the emission surface F2 does not protrude in the b1 direction beyond the end of the b1 direction of the ejection surface F1. In this embodiment, the end of the b1 direction of the ejection surface F1 is provided at the same position in the b1 direction as the end of the b1 direction of the emission surface F2. The end of the b2 direction of the emission surface F2 may protrude in the b2 direction beyond the end of the b2 direction of the ejection surface F1, or may not protrude. In FIG. 4, the end of the b2 direction of the emission surface F2 protrudes in the b2 direction beyond the end of the b2 direction of the ejection surface F1. With this configuration, the energy emission unit 330 can cure a wide range of ink at once in the curing operation described later. However, since the end of the emission surface F2 protruding in the b2 direction may interfere with the workpiece W, the end of the emission surface F2 on the b2 direction side may be designed not to protrude in the b2 direction beyond the end of the ejection surface F1 on the b2 direction side as necessary.

[0093] As shown in FIG. 4, among the multiple nozzles N provided on the nozzle surface F11, the ejection nozzles that eject ink during printing and contribute to image formation are not provided at a position that protrudes outward in the b-axis direction from between the end on the b1 direction side and the end on the b2 direction side of the window surface F21 of the energy emission unit 330. In other words, the ejection nozzles are located between the end on the b1 direction side and the end on the b2 direction side of the window surface F21. Note that the multiple nozzles N provided on the nozzle surface F11 may include dummy nozzles that do not eject ink during printing and do not contribute to image formation. Such dummy nozzles do not have to be located between the end on the b1 direction side and the end on the b2 direction side of the window surface F21.

[0094] As shown in FIG. 4, when the head unit 300 is viewed in the c1 direction, the end of the measurement surface F3 on the b1 side does not protrude in the b1 direction further than the end of the ejection surface F1 on the b1 side. Similarly, the end of the measurement surface F3 on the b2 side does not protrude in the b2 direction further than the end of the ejection surface F1 on the b2 side. That is, in this embodiment, the position of the measurement surface F3 in the b-axis direction is between the end of the ejection surface F1 on the b1 side and the end of the ejection surface F1 on the b2 side. However, the end of the measurement surface F3 on the b2 side may protrude in the b2 direction further than the end of the ejection surface F1 on the b2 side.

[0095] 1-4. Operation of the three-dimensional object printing device and three-dimensional object printing method Fig. 6 is a flowchart showing the flow of the three-dimensional object printing method according to the first embodiment. The three-dimensional object printing method is performed using the above-mentioned three-dimensional object printing apparatus 100. As shown in Fig. 6, the three-dimensional object printing apparatus 100 executes, in this order, step S110 for setting a path, step S120 for performing a printing operation, and step S130 for performing a curing operation.

[0096] 7A to 7C are diagrams for explaining the path setting and printing operation in the first embodiment, and the positions and postures of the head unit 300 over time are shown in the order of FIGS. 7A to 7C. The workpiece W in this embodiment has a surface WF that is a concave curved surface, and printing is performed on the surface WF by the three-dimensional object printing apparatus 100. The dashed arrows in FIGS. 7A to 7C indicate the path RU, and the arrows indicate the movement direction of the head unit 300 on the path RU. In other words, this movement direction is the direction in which the head unit 300 moves relatively along the workpiece W, and this movement is performed by the robot 200.

[0097] In step S110, a route RU is set as a route along which a representative point inside or in the vicinity of the head unit 300 should move, based on work information indicating the position and shape of the work W. In this embodiment, the representative point is set on the ejection surface F1, and the route RU also includes information regarding the attitude of the ejection surface F1. The representative point corresponds to a TCP (Tool Center Point) in robot teaching. It is preferable that the route RU and its direction are set along the surface WF, and the attitude and moving direction of the ejection surface F1 change from time to time along the route RU in response to the surface WF. By setting the route RU in this manner, the computer 700 generates the above-mentioned route information Db. In this embodiment, the route RU is set so that the head unit 300 scans the surface WF approximately in the X1 direction.

[0098] Here, the distance between the path RU and the surface WF is substantially constant, and the angle between the normal to the ejection surface F1 of the head 310 and the surface WF is substantially constant. Therefore, the distance L between the ejection surface F1 and the surface WF in the normal direction of the ejection surface F1 is substantially constant over the entire area of ​​the path RU. This makes it possible to reduce the error in the landing position of the ink from the head 310 to the surface WF. Also, in the example shown in FIGS. 7A to 7C, the normal to the ejection surface F1 is orthogonal or substantially orthogonal to the surface WF. This makes it easier to improve print quality compared to when the normal to the ejection surface F1 is inclined with respect to the surface WF.

[0099] In step S120, while the head unit 300 moves along the path RU, the head 310 ejects ink toward the surface WF of the workpiece W, thereby performing printing. At this time, the a1 direction in the above-mentioned tool coordinate system faces the direction of the path RU. That is, the head 310 moves in a direction perpendicular to both the nozzle row axis and the ejection direction. The distance measurement unit 360 is located forward of the head 310 in the movement direction. Also, the head 310 is located forward of the energy emission unit 330 in the movement direction. In other words, in the printing operation, the measurement surface F3 is located on the movement direction side of the ejection surface F1. Also, the ejection surface F1 is located on the movement direction side of the emission surface F2.

[0100] In step S120, energy can be emitted from the energy emission unit 330 at the same time as the head unit 300 moves and the head 310 ejects ink. That is, in this embodiment, ultraviolet light can be irradiated onto the surface WF to harden the ink that has landed on the surface WF.

[0101] In step S120, simultaneously with the movement of the head unit 300 and the ejection of ink by the head 310, the distance between the head unit 300 and the surface WF can also be measured by the distance measurement unit 360. That is, in this embodiment, the distance between the head unit 300 and the surface WF can be measured by the distance measurement unit 360, and based on a signal from the distance measurement unit 360, the robot 200 can also be controlled to keep the aforementioned distance L constant.

[0102] In step S130, a curing operation is performed to cure the ink that has landed on the surface WF in step S120. Note that in step S120, if energy is emitted from the energy emission unit 330 as described above and the ink is sufficiently cured and fixed on the surface WF, step S130 can be omitted. In the curing operation in step S130, the robot 200 is operated to emit energy from the energy emission unit 330 while scanning the surface WF with the energy emission unit 330. The path in the curing operation may be the same as or different from the path RU in the printing operation. Also, in step S130, the curing operation can be performed using a curing means (not shown) provided separately from the energy emission unit 330.

[0103] By the three-dimensional object printing apparatus 100 executing steps S110 to S130 described above, printing on the surface WF of the workpiece W with ink is completed.

[0104] In this embodiment, the head unit 300 has both the energy emission unit 330 and the distance measurement unit 360, but one of them may be omitted. For example, if curable ink is not used, the energy emission unit 330 may not be provided. For example, if the movement path of the robot 200 is determined in advance, the distance measurement unit 360 may not be provided.

[0105] In the three-dimensional object printing device 100 in this embodiment, the ejection surface F1 of the head 310 is located on the c2 direction side of the exit surface F2 of the energy emission unit 330. In other words, the ejection surface F1 is located on the ink ejection direction side of the exit surface F2. Therefore, when the relative position and posture of the ejection surface F1 with respect to the workpiece W is set to a desired position and posture, it is possible to prevent contact between the exit surface F2 and the workpiece W. In particular, when the ejection surface F1 and the surface WF of the workpiece W are brought closer to each other while facing each other, the ejection surface F1 can be brought closer to the surface WF than the exit surface F2 in the ejection direction. Therefore, it is possible to improve the accuracy of the position where the ink ejected from the nozzle N of the head 310 lands on the surface WF, and to improve the printing quality. In addition, since the head unit 300 includes the energy emission unit 330 having the exit surface F2, it is possible to immediately irradiate energy to the ink that has landed on the surface WF and harden the ink.

[0106] In the three-dimensional object printing device 100 of this embodiment, the positional relationship between the ejection surface F1 and the emission surface F2 is fixed in the head unit 300. This results in a simpler configuration and easier control compared to a head unit configuration in which the positional relationship between the ejection surface F1 and the emission surface F2 is variable using, for example, a linear actuator.

[0107] In the three-dimensional object printing device 100 in this embodiment, when the head 310 is viewed in the nozzle row axis direction in a state in which the fifth rotation axis O5, which is the central rotation axis, and the nozzle row axis are parallel to each other, if the distance between the end F1a of the ejection surface F1 that is farthest from the fifth rotation axis O5 and the fifth rotation axis O5 is R, the ejection surface F2 and the measurement surface F3 are located inside a virtual circle C with a radius of R centered on the fifth rotation axis O5. Therefore, in a printing posture in which the ejection surface F1 and the workpiece W are brought close to each other in opposition, when the head unit 300 is rotated around the fifth rotation axis O5, it is possible to prevent the energy ejection unit 330 and the distance measurement unit 360 from interfering with the workpiece W.

[0108] In the three-dimensional object printing device 100 in this embodiment, the ejection surface F1 of the head 310 is located on the c2 direction side of the measurement surface F3 of the distance measurement unit 360. In other words, the ejection surface F1 is located on the ink ejection direction side of the measurement surface F3. Therefore, when the relative position and posture of the ejection surface F1 with respect to the workpiece W is set to a desired position and posture, it is possible to prevent contact between the measurement surface F3 and the workpiece W. In particular, when the ejection surface F1 and the surface WF of the workpiece W are brought closer to each other while facing each other, the ejection surface F1 can be brought closer to the surface WF than the measurement surface F3 in the ejection direction. Therefore, it is possible to improve the accuracy of the position where the ink ejected from the nozzle N of the head 310 lands on the surface WF, and to improve the printing quality. In addition, since the head unit 300 includes a distance detection means having the measurement surface F3, it is possible to accurately measure the distance between the head unit 300 and the workpiece W.

[0109] In the three-dimensional object printing apparatus 100 of this embodiment, the positional relationship between the ejection surface F1 and the measurement surface F3 is fixed in the head unit 300. This results in a simpler configuration and easier control compared to a head unit configuration in which the positional relationship between the ejection surface F1 and the measurement surface F3 is variable using, for example, a linear actuator.

[0110] In the three-dimensional object printing device 100 in this embodiment, the emission surface F2 is located between the measurement surface F3 and the ejection surface F1 in the ejection direction. Therefore, since the energy emitted from the emission surface F2 is irradiated to the ink that has landed on the surface WF of the workpiece W while maintaining a sufficient intensity, it is possible to efficiently harden the ink. In other words, by shortening the distance between the surface WF and the emission surface F2, it is possible to suppress the attenuation of the energy emitted from the emission surface F2 before it reaches the surface WF, compared to the case where the distance is increased. In addition, the number of cases where it is necessary to separate the entire head unit 300 from the workpiece W to prevent contact between the measurement surface F3 and the workpiece W is reduced. Therefore, it is possible to improve the accuracy of the position where the ink ejected from the nozzle N of the head 310 lands on the surface WF, and to improve the printing quality. In addition, since the energy emitted from the emission surface F2 is irradiated to the ink that has landed on the surface WF while maintaining a sufficient intensity, it is possible to efficiently harden the ink.

[0111] In the three-dimensional object printing apparatus 100 in this embodiment, the distance between the emission surface F2 and the ejection surface F1 in the ejection direction is shorter than the distance between the measurement surface F3 and the ejection surface F1. Therefore, when the head unit 300 is brought closer to the workpiece W, the distance between the ejection surface F1 and the surface WF and the distance between the emission surface F2 and the surface WF can be narrowed compared to the distance between the measurement surface F3 and the surface WF. In addition, the number of cases where it is necessary to separate the entire head unit 300 from the workpiece W to prevent contact between the measurement surface F3 and the workpiece W is reduced. Therefore, it is possible to improve the accuracy of the position where the ink ejected from the nozzle N of the head 310 lands on the surface WF and improve the printing quality. In addition, since the energy emitted from the emission surface F2 is irradiated to the ink that has landed on the surface WF while maintaining a sufficient intensity, it is possible to efficiently harden the ink.

[0112] In the printing operation, in the three-dimensional object printing device 100, a plurality of nozzles N are provided along the nozzle row axis on the discharge surface F1, and in the a-axis direction perpendicular to both the nozzle row axis and the discharge direction, the discharge surface F1 is located between the emission surface F2 and the measurement surface F3. In addition, it is possible to simultaneously perform the following: moving the head unit 300 by the robot 200, discharging ink from the head 310 onto the surface WF of the workpiece W, and emitting energy from the energy emission unit 330.

[0113] As shown in FIG. 7A to FIG. 7C, the three-dimensional object printing device 100 moves the head unit 300 in the a-axis direction perpendicular to both the nozzle row axis and the ejection direction. During this printing operation, the measurement surface F3 is located on the movement direction side of the ejection surface F1, so the measurement surface F3 scans the area of ​​the surface WF before the ejection surface F1. Therefore, the measurement surface F3 scans the area of ​​the surface WF to measure the distance between the area and the head unit 300, and then the ejection surface F1 scans the area of ​​the surface WF to eject ink from the head 310. At this time, the distance L can be controlled to be kept constant based on the distance measurement result. In addition, it is possible to prevent the area of ​​the surface WF from contacting the ejection surface F1. Furthermore, it is possible to complete the distance measurement and ink ejection in a series of operations.

[0114] As shown in Figs. 7A to 7C, the three-dimensional object printing device 100 moves the head unit 300 in the a-axis direction perpendicular to both the nozzle row axis and the ejection direction. During this printing operation, the ejection surface F1 is located closer to the movement direction than the emission surface F2, so the ejection surface F1 scans the area on the surface WF before the emission surface F2. For this reason, first, ink is ejected from the head 310 to the relevant area on the surface WF, and then the emission surface F2 can be brought close to the relevant area of ​​the workpiece W on which the ink has landed. Therefore, it is possible to complete the ejection of ink and the curing of the ink by irradiation of energy in a series of operations.

[0115] When the head unit 300 is viewed from the ejection direction side, the downstream flow path 422, which is a part of the supply flow path 420 that supplies ink to the head 310, is located between the distance measurement unit 360 and the energy emission unit 330, and the distance measurement unit 360 and the energy emission unit 330 generate heat when driven. Therefore, the heat generated from the distance measurement unit 360 and the energy emission unit 330 is transmitted to the downstream flow path 422 located between them, the ink in the flow path is heated, and the viscosity of the ink decreases. Therefore, ejection defects caused by clogging of ink in the head 310 or the downstream flow path 422 can be suppressed.

[0116] In the three-dimensional object printing device 100 in this embodiment, the width W310 of the ejection surface F1 in the a-axis direction perpendicular to both the nozzle row axis and the ejection direction is narrower than the width W330 of the exit surface F2 in the a-axis direction. This makes it easier to bring the ejection surface F1 close to, for example, a recess in the workpiece W. In addition, since the width W330 of the exit surface F2 in the movement direction is wide, the time that the exit surface F2 scans the surface WF on the workpiece W during the printing operation becomes longer. Therefore, after the ink is ejected from the head 310, the ink that has landed on the surface WF can be irradiated with sufficient energy to harden the ink.

[0117] In the three-dimensional object printing device 100 of this embodiment, the energy emission unit 330 may be tilted so that the emission surface F2 faces the side opposite to the side where the head 310 is located. With this three-dimensional object printing device 100, the energy emitted from the emission surface F2 is unlikely to be incident on the ejection surface F1. Therefore, it is possible to prevent the ink adhering to the ejection surface F1 or the ink forming the meniscus in the nozzle N from being irradiated with energy, hardening the ink, and causing ejection defects.

[0118] 2. Second embodiment A second embodiment of the present invention will be described below. In the following example, for elements having the same actions and functions as those in the first embodiment, the reference numerals used in the description of the first embodiment will be used and detailed descriptions of each will be omitted as appropriate.

[0119] FIG. 8 is a perspective view showing an outline of a three-dimensional object printing apparatus 100 and a workpiece W according to the second embodiment. The configuration of the three-dimensional object printing apparatus 100 in this embodiment is the same as that in the first embodiment. The workpiece W in this embodiment has a protruding portion WP protruding in the Z1 direction, and the surface WF that becomes the printing area is located adjacent to the Y2 direction side of the protruding portion WP. The protruding portion WP extends along the X axis. The size, shape, or installation posture of the workpiece W is not limited to the example shown in FIG. 8, and is arbitrary.

[0120] 9 is a plan view for explaining the setting of the path and the printing operation in the second embodiment. In this embodiment, the head unit 300 in the path RU is oriented so that the ejection surface F1 faces the surface WF on the Z1 direction side of the workpiece W, and the b1 direction of the tool coordinate system faces the protrusion WP. The movement direction in the path RU is the X1 direction of the base coordinate system, and the a1 direction of the tool coordinate system is parallel to the X1 direction. While moving on the path RU by the operation of the robot 200, the head unit 300 moves along the path RU, and the head 310 ejects ink toward the surface WF of the workpiece W, thereby performing a printing operation.

[0121] When the head unit 300 is viewed in the c2 direction, the end of the emission surface F2 on the b1 side does not protrude in the b1 direction further than the end of the ejection surface F1 on the b1 side. In this embodiment, the end of the ejection surface F1 on the b1 side is provided at the same position in the b1 direction as the end of the emission surface F2 on the b1 side. With this configuration of the head unit 300, it is possible to prevent the emission surface F2 from interfering with the protrusion WP when printing is performed on an area of ​​the surface WF adjacent to the protrusion WP. Note that the end of the ejection surface F1 on the b1 side may be provided in the b1 direction further than the end of the emission surface F2 on the b1 side.

[0122] Furthermore, when the head unit 300 is viewed in the c2 direction, the end of the emission surface F2 on the b2 side may protrude in the b2 direction further than the end of the ejection surface F1 on the b2 side. This is because the end on the b2 side does not face the protrusion WP, and therefore no interference occurs. However, if another protrusion of the workpiece W is provided on the b2 side, the end of the emission surface F2 on the b2 side may be provided so as not to protrude in the b2 direction further than the end of the ejection surface F1 on the b2 side.

[0123] In addition, in this embodiment, when the head unit 300 is viewed in the c2 direction, the end of the measurement surface F3 in the b-axis direction does not protrude outward from the end of the ejection surface F1 in the b-axis direction. Alternatively, the end of the measurement surface F3 in the b-axis direction may be provided at the same position in the b-axis direction as the end of the ejection surface F1 in the b-axis direction. In any case, it is sufficient that the end of the measurement surface F3 in the b-axis direction does not protrude beyond the end of the ejection surface F1 in the b-axis direction in the b1 direction or the b2 direction, but it is preferable that the end of the measurement surface F3 in the b-axis direction does not protrude beyond the end of the ejection surface F1 in the b-axis direction in both the b1 direction and the b2 direction. According to such a configuration of the head unit 300, when printing is performed on an area of ​​the surface WF adjacent to the protruding portion WP, it is possible to prevent the measurement surface F3 from interfering with the protruding portion WP. It is preferable that the direction in which the end of the measurement surface F3 does not protrude beyond the end of the ejection surface F1 in the b-axis direction is aligned with the emission surface F2 and the measurement surface F3.

[0124] 3. Third embodiment The third embodiment of the present invention will be described below. In the following exemplary embodiment, for elements having the same actions and functions as those in the first embodiment, the reference numerals used in the description of the first embodiment will be used and detailed descriptions of each will be omitted as appropriate.

[0125] FIG. 10 is a side view showing an outline of the head unit 300 and the workpiece W according to the third embodiment. The configuration of the three-dimensional object printing apparatus 100 in this embodiment is the same as that in the first embodiment. The workpiece W in this embodiment has a protruding portion WP protruding in the Z1 direction, and the surface WF that becomes the printing area is located adjacent to the X1 direction side of the protruding portion WP. The protruding portion WP extends along the Y axis. The size, shape, or installation posture of the workpiece W is not limited to the example shown in FIG. 10 and is arbitrary.

[0126] 10, the head unit 300 in the path RU in this embodiment is oriented so that the ejection surface F1 faces the surface WF on the Z1 direction side of the workpiece W, the a2 direction faces the protrusion WP, and the a1 direction faces the surface WF. The movement direction of the head unit 300 in the path RU is the X1 direction of the base coordinate system, and the a-axis of the tool coordinate system is parallel to the X-axis. While moving on the path RU by the operation of the robot 200, the head unit 300 moves along the path RU, and the head 310 ejects ink toward the surface WF of the workpiece W, thereby performing a printing operation.

[0127] In the three-dimensional object printing method of this embodiment, when ink is ejected from the head 310 by making the ejection surface F1 face the surface WF, the ejection surface F2 overlaps with the protrusion WP when viewed in the ejection direction. Here, the ejection direction is the c2 direction. At this time, as shown in FIG. 10, at least a part of the protrusion WP is located between the ejection surface F1 and the ejection surface F2 in the c-axis direction.

[0128] According to the three-dimensional object printing method described above, the number of cases where it is necessary to separate the entire head unit 300 from the workpiece W to prevent contact between the emission surface F2 and the workpiece W is reduced. In particular, even if the printing area of ​​the workpiece W is adjacent to the protruding portion WP, it is possible to bring the ejection surface F1 close to the printing area of ​​the workpiece W while preventing contact between the emission surface F2 and the workpiece W. Therefore, it is possible to increase the accuracy of the position where the ink ejected from the nozzle N of the head 310 lands on the surface WF, thereby improving the printing quality. [Explanation of symbols]

[0129] 100...three-dimensional object printing device, 200...robot, 210...base, 220, 221, 222, 223, 224, 225, 226...arm, 230...joint portion, 240...arm drive mechanism, 241...encoder, 300...head unit, 310...head, 311...piezoelectric element, 312...nozzle plate, 313...casing portion, 314...cover member, 320...pressure regulating valve, 330...energy emission portion, 331...window portion, 332...casing portion, 340...switch circuit, 350...support, 360...distance measurement portion, 361...window portion, 362...casing portion, 400...liquid supply unit, 410...liquid storage portion, 420...supply flow path, 421...upstream flow path, 422...downstream flow path, 500...control module module, 510...timing signal generating circuit, 520...power supply circuit, 530...control circuit, 540...drive signal generating circuit, 600...controller, 610...memory circuit, 620...processing circuit, 700...computer, C...virtual circle, F1...ejection surface, F2...emission surface, F3...measurement surface, F11...nozzle surface, F12...cover surface, F21...window surface, F22...casing surface, F31...window surface, F32...casing surface, La...first nozzle row, Lb...second nozzle row, N...nozzle, O1...first rotating shaft, O2...second rotating shaft, O3...third rotating shaft, O4...fourth rotating shaft, O5...fifth rotating shaft, O6...sixth rotating shaft, RU...path, W...work, W310, W330, W331...width, WF...surface, WP...protrusion.

Claims

1. The nozzle is provided on a discharge surface, and liquid is discharged from the nozzle onto a three-dimensional workpiece. a head for applying the energy to the liquid, and a curing means having an emission surface for emitting energy capable of curing the liquid; A head unit including: a moving mechanism for changing the relative position and attitude of the work and the head unit; , If the direction in which the head ejects the liquid is defined as an ejection direction, the ejection surface is located on the ejection direction side of the exit surface, In the head unit, the positional relationship between the ejection surface and the emission surface is fixed. It has been said that A three-dimensional object printing device.

2. The curing means includes a housing portion and a window portion through which the energy is emitted, The lower surface of the housing part in the ejection direction is is also located on the discharge direction side, 2. The three-dimensional object printing apparatus according to claim 1 .

3. A plurality of nozzles are provided on the ejection surface along a nozzle row axis, The moving mechanism includes a plurality of rotation axes including a rotation axis that can be parallel to the nozzle row axis. R, Among the rotation axes that can be parallel to the nozzle row axis, the rotation axis that is closest to the head unit The head is rotated in a state where the central rotation axis and the nozzle row axis are parallel to each other. When viewed along the Zuru column axis, Among the ends of the ejection surface, an end farthest from the central rotation axis and a distance between the end and the central rotation axis If the distance is R, then The emission surface is located inside a virtual circle having a radius R and centered on the central rotation axis.

3. The three-dimensional object printing device according to claim 1 or 2.

4. The head unit is a distance measuring device having a measuring surface for measuring a relative distance to the workpiece. The method further includes: The ejection surface is located on the ejection direction side of the measurement surface. The three-dimensional object printing device according to any one of claims 1 to 3.

5. In the head unit, the positional relationship between the ejection surface and the measurement surface is fixed. It has been 5. The three-dimensional object printing apparatus according to claim 4.

6. The head unit is a distance measuring device having a measurement surface for measuring a relative distance to the workpiece. The method further includes: the ejection surface is located on the ejection direction side of the measurement surface, A plurality of nozzles are provided on the ejection surface along a nozzle row axis, The moving mechanism includes a plurality of rotation axes including a rotation axis that can be parallel to the nozzle row axis. R, Among the rotation axes that can be parallel to the nozzle row axis, the rotation axis that is closest to the head unit The head is rotated in a state where the central rotation axis and the nozzle row axis are parallel to each other. When viewed along the Zuru column axis, Among the ends of the ejection surface, an end farthest from the central rotation axis and a distance between the end and the central rotation axis If the distance is R, then the exit surface is located inside a virtual circle having a radius R and centered on the central rotation axis, The measurement surface is located inside the virtual circle.

3. The three-dimensional object printing device according to claim 1 or 2.

7. In the ejection direction, the emission surface is located between the measurement surface and the ejection surface. The three-dimensional object printing device according to any one of claims 4 to 6.

8. In a direction perpendicular to both the scanning direction in which the head unit is scanned and the ejection direction The ejection surface is located between the emission surface and the measurement surface. The three-dimensional object printing device according to any one of claims 4 to 7.

9. The nozzle is provided on a discharge surface, and liquid is discharged from the nozzle onto a three-dimensional workpiece. a head for applying the energy to the liquid, and a curing means having an emission surface for emitting energy capable of curing the liquid; A head unit including a distance measuring means having a measuring surface for measuring a relative distance to the workpiece. Knit and a moving mechanism for changing the relative position and attitude of the work and the head unit; , If the direction in which the head ejects the liquid is defined as an ejection direction, the ejection surface is located on the ejection direction side of the exit surface, the ejection surface is located on the ejection direction side of the measurement surface, When the head unit is viewed from the ejection direction side, At least a part of the flow path for supplying the liquid to the head includes the distance measuring means and the Located between the hardening means and The distance measuring means and the hardening means generate heat when driven. A three-dimensional object printing device.

10. In a direction perpendicular to both the scanning direction in which the head unit is scanned and the ejection direction wherein the width of the ejection surface is narrower than the width of the emission surface, The three-dimensional object printing device according to any one of claims 1 to 7 and 9. .

11. The nozzle is provided on a discharge surface, and liquid is discharged from the nozzle onto a three-dimensional workpiece. a head for applying the energy to the liquid, and a curing means having an emission surface for emitting energy capable of curing the liquid; A head unit including: a moving mechanism for changing the relative position and attitude of the work and the head unit; , If the direction in which the head ejects the liquid is defined as an ejection direction, the ejection surface is located on the ejection direction side of the exit surface, In a direction perpendicular to both the scanning direction in which the head unit is scanned and the ejection direction wherein the width of the ejection surface is narrower than the width of the emission surface, A three-dimensional object printing device.

12. The nozzle is provided on a discharge surface, and liquid is discharged from the nozzle onto a three-dimensional workpiece. a head for applying the energy to the liquid, and a curing means having an emission surface for emitting energy capable of curing the liquid; A head unit including: a moving mechanism for changing the relative position and attitude of the work and the head unit; , If the direction in which the head ejects the liquid is defined as an ejection direction, the ejection surface is located on the ejection direction side of the exit surface, The emission surface is inclined so as to face the side opposite to the side where the head is located. A three-dimensional object printing device.

13. At least one side of the scanning direction in which the head unit is scanned is The end does not protrude beyond the end of the ejection surface. The structure according to any one of claims 1 to 7, 9, 11 and 12. Physical printing device.

14. At least one side of the measurement surface in the scanning direction in which the head unit is scanned The end does not protrude beyond the end of the ejection surface. The three-dimensional object printing device according to any one of claims 4 to 9.

15. The moving mechanism is a multi-joint robot having multiple joints. The three-dimensional object printing device according to any one of claims 1 to 14.

16. The nozzle is provided on a discharge surface, and liquid is discharged from the nozzle onto a three-dimensional workpiece. a head for applying the energy to the liquid, and a curing means having an emission surface for emitting energy capable of curing the liquid; A three-dimensional printing method for printing on a printing area of ​​the work by a head unit having 1. A method comprising: When the direction in which the head ejects the liquid is defined as an ejection direction, the ejection surface is the exit surface. is located on the discharge direction side of the The workpiece is provided with a protrusion protruding toward the head unit at a position different from the printing area. Having a department, When the ejection surface faces the printing area and the liquid is ejected from the head, The emission surface overlaps with the protrusion when viewed in the ejection direction. A three-dimensional object printing method.

17. When the ejection surface is opposed to the printing area and the liquid is ejected from the head, In the ejection direction, at least a part of the protrusion is located between the ejection surface and the emission surface. Located between The method for printing a three-dimensional object according to claim 16 .

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