Stereoscopic object printing apparatus and stereoscopic object printing method

Abstract

The present invention provides a three-dimensional object printing device and a three-dimensional object printing method that enable a printing head and other structural elements to function individually and prevent contact with a workpiece as much as possible when printing is performed on a three-dimensional object. The three-dimensional object printing device has a head unit (300) that includes a head (310) having an ejection surface (F1) provided with a nozzle (N) and that ejects ink from the nozzle (N) toward a three-dimensional workpiece, and an energy ejection section (330) having an ejection surface (F2) that ejects energy capable of hardening the ink; and a robot that changes the relative positions and postures of the workpiece and the head unit (300), and when the direction in which the head (310) ejects ink is set as an ejection direction, the ejection surface (F1) is located on the ejection direction side compared with the ejection surface (F2).

Description

TECHNICAL FIELD

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

[0002] A three-dimensional object printing apparatus that performs printing on a surface of a three-dimensional object by an inkjet method is known. For example, a system described in Patent Literature 1 has a robot and a printing head disposed on the robot, and causes ink droplets to be ejected from the printing head toward a curved surface of a vehicle.

[0003] In Patent Literature 1, a technique is described in which a hardening head disposed on the robot in the vicinity of the printing head is caused to scan in the same manner as the printing head, thereby hardening the ink immediately after printing.

[0004] However, if the hardening head is disposed in the vicinity of the printing head, there is a possibility that the hardening head comes into contact with the workpiece when the printing head is set to a desired position and posture with respect to the three-dimensional workpiece as a printing target. Thus, as the hardening head, a distance measuring unit, and the like, it is necessary to provide a structural element that exerts an action on the workpiece or receives an action from the workpiece in the vicinity of the printing head, and on the other hand, it is also desirable that they each function and that contact with the workpiece is prevented as much as possible. From the viewpoints exemplified above, one of the problems is to appropriately dispose the structural elements such as the hardening head, the distance measuring unit, and the like in the vicinity of the printing head.

[0005] Patent Literature 1: Japanese Patent Application Laid-Open No. 2015-520011 SUMMARY

[0006] A three-dimensional object printing apparatus has: a head unit including a head having an ejection face provided with a nozzle and ejecting a liquid from the nozzle toward a three-dimensional workpiece, and a hardening unit having an emission face that emits energy capable of hardening the liquid; and a moving mechanism that changes a relative position and a posture of the workpiece and the head unit, wherein, when a direction in which the head ejects the liquid is set as an ejection direction, the ejection face is located on a side of the ejection direction compared to the emission face.

[0007] A three-dimensional object printing apparatus has: a head unit including a head having an ejection face provided with a nozzle and ejecting a liquid from the nozzle toward a three-dimensional workpiece, and a distance measuring unit having a measurement face that measures a relative distance from the workpiece; and a moving mechanism that changes a relative position and a posture of the workpiece and the head unit, wherein, when a direction in which the head ejects the liquid is set as an ejection direction, the ejection face is located on a side of the ejection direction compared to the measurement face.

[0008] A stereoscopic object printing method performs printing to a printing region of a stereoscopic workpiece by a head unit, the head unit including: a head including an ejection surface provided with nozzles and ejecting a liquid from the nozzles toward the workpiece; and a hardening unit including an emission surface that emits energy capable of hardening the liquid, in the stereoscopic object printing method, when a direction in which the head ejects the liquid is set as an ejection direction, the ejection surface is located on a side of the ejection direction compared to the emission surface, the workpiece has a protruding portion protruding toward the head unit at a position different from the printing region, and when the ejection surface opposes the printing region and the liquid is ejected from the head, the emission surface overlaps the protruding portion when viewed in the ejection direction. BRIEF DESCRIPTION OF DRAWINGS

[0009] Figure 1 A perspective view showing an outline of a stereoscopic object printing apparatus and a workpiece according to the first embodiment.

[0010] Figure 2 A block diagram showing an electrical structure of a stereoscopic object printing apparatus according to the first embodiment.

[0011] Figure 3 A perspective view showing a structure of a head unit in the first embodiment.

[0012] Figure 4 A plan view showing a structure of a head unit in the first embodiment.

[0013] Figure 5 A side view showing a positional relationship between a head unit and an arm in the first embodiment.

[0014] Figure 6 A flowchart showing a flow of a stereoscopic object printing method according to the first embodiment.

[0015] Figure 7A A side view for explaining setting of a path and a printing operation in the first embodiment.

[0016] Figure 7B A side view for explaining setting of a path and a printing operation in the first embodiment.

[0017] Figure 7C A side view for explaining setting of a path and a printing operation in the first embodiment.

[0018] Figure 8 A perspective view showing an outline of a stereoscopic object printing apparatus and a workpiece according to the second embodiment.

[0019] Figure 9A plan view for explaining the setting of the path and the printing operation in the second embodiment.

[0020] Figure 10 A side view for explaining the setting of the path and the printing operation in the third embodiment. DETAILED DESCRIPTION

[0021] Hereinafter, a preferred embodiment to which the present application pertains will be described with reference to the drawings. In addition, in the drawings, the size or scale of each part is appropriately different from the actual situation, and there are also parts that are schematically shown for easy understanding. Furthermore, as long as there is no description in the following explanation that defines the meaning of the present application, the scope of the present application is not limited to these modes.

[0022] The following explanation is appropriately made using an X axis, a Y axis, and a Z axis that cross each other. Furthermore, one direction along the X axis is referred to as an XI direction, and the direction opposite to the XI direction is referred to as an X2 direction. Likewise, the directions opposite to each other along the Y axis are referred to as a Yl direction and a Y2 direction. Furthermore, the directions opposite to each other along the Z axis are referred to as a Zl direction and a Z2 direction.

[0023] Here, the X axis, the Y axis, and the Z axis are coordinate axes of a basic coordinate system set in a space in which a workpiece W and a base 210 described later are disposed. Typically, the Z axis is an upright axis, and the Z2 direction corresponds to a downward direction in the upright direction. In addition, the Z axis can also be an axis other than an upright axis. Furthermore, although the X axis, the Y axis, and the Z axis are typically orthogonal to each other, they are not limited thereto, and there are cases in which they are not orthogonal. For example, the X axis, the Y axis, and the Z axis can cross each other at an angle in a range of 80° or more and 100° or less.

[0024] 1. First Embodiment

[0025] 1-1. Outline of Stereoscopic Object Printing Device

[0026] Figure 1 A perspective view showing an outline of a stereoscopic object printing device 100 pertaining to the embodiment. The stereoscopic object printing device 100 is a device that performs printing on a surface of a stereoscopic workpiece W by an inkjet method.

[0027] The workpiece W has a face WF that is a printing target. In the example shown in Figure 1 the example shown in FIG. 1, the face WF is a concave curved surface having a plurality of portions with different curvatures. The size, shape, or disposition posture of the workpiece W is not limited to Figure 1 the example shown in FIG. 1, and is in an arbitrary mode.

[0028] In the example shown in FIG. 1, the stereoscopic object printing device 100 is a device that performs printing on the face WF of the workpiece W by an inkjet method. Figure 1In the example shown, the stereoscopic object printing apparatus 100 is an inkjet printer using a vertical multi-joint robot. Specifically, as shown in FIG. 1, the stereoscopic object printing apparatus 100 includes a robot 200, a head unit 300, a liquid supply unit 400, and a controller 600. Figure 1 As shown, the stereoscopic object printing apparatus 100 has the robot 200, the head unit 300, the liquid supply unit 400, and the controller 600. Hereinafter, first, each of the parts of the stereoscopic object printing apparatus 100 will be described in order. Figure 1 Each of the parts of the stereoscopic object printing apparatus 100 shown will be briefly described.

[0029] 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, the robot 200 is a so-called six-axis vertical multi-joint robot. Specifically, the robot 200 has a base 210 and an arm 220. Figure 1 In the example shown, the robot 200 is a so-called six-axis vertical multi-joint robot. Specifically, the robot 200 has a base 210 and an arm 220.

[0030] The base 210 is a table that supports the arm 220. In the example shown, the base 210 is fixed on a setting surface such as a floor surface facing the Zl direction by screwing or the like. Alternatively, the setting surface on which the base 210 is fixed can be a surface facing an arbitrary direction, and is not limited to a surface facing the Zl direction. Figure 1 In the example shown, the base 210 is fixed on a setting surface such as a floor surface facing the Zl direction by screwing or the like. Alternatively, the setting surface on which the base 210 is fixed can be a surface facing an arbitrary direction, and is not limited to a surface facing the Zl direction. Figure 1 In the example shown, the base 210 is fixed on a setting surface such as a floor surface facing the Zl direction by screwing or the like. Alternatively, the setting surface on which the base 210 is fixed can be a surface facing an arbitrary direction, and is not limited to a surface facing the Zl direction.

[0031] The arm 220 is a six-axis robot arm having a base end installed on the base 210 and a top end that changes the position and posture in three dimensions with respect to the base end. Specifically, the arm 220 has an arm 221, an arm 222, an arm 223, an arm 224, an arm 225, and an arm 226, which are connected in this order.

[0032] The arm 221 is connected to the base 210 via a joint portion 230_1 so as to be able to rotate around a first rotation axis Ol. The arm 222 is connected to the arm 221 via a joint portion 230_2 so as to be able to rotate around a second rotation axis 02. The arm 223 is connected to the arm 222 via a joint portion 230_3 so as to be able to rotate around a third rotation axis 03. The arm 224 is connected to the rotating arm 223 via a joint portion 230_4 so as to be able to rotate around a fourth rotation axis 04. The arm 225 is connected to the arm 224 via a joint portion 230_5 so as to be able to rotate around a fifth rotation axis 05. The arm 226 is connected to the arm 225 via a joint portion 230_6 so as to be able to rotate around a sixth rotation axis 06. In the following, there are cases in which each of the joint portions 230_1 to 230_6 is referred to as a joint portion 230.

[0033] The joint portion 230 is one example of a movable portion. In the example shown, the joint portion 230 is a so-called revolute joint. Figure 1 In the example shown, the number of joint portions 230 is six. In the example shown, the joint portions 230 are each a revolute joint. Figure 1In the example shown, joints 230_1 to 230_6 are mechanisms that connect one of two adjacent arms to the other in a rotatable manner. Although in Figure 1 Although not shown in the diagram, drive mechanisms for rotating one of two adjacent arms relative to the other are provided on joints 230_1 to 230_6, respectively. These drive mechanisms include, for example, a motor that generates a driving force for the rotation, a reducer that slows down and outputs the driving force, and an encoder such as a rotary encoder that measures the amount of motion, such as the angle of rotation. Furthermore, the assembly of these drive mechanisms corresponds to the following... Figure 2 The arm drive mechanism 240 is shown. Furthermore, the encoder corresponds to the one described later. Figure 2 The encoder 241 is shown in the figure.

[0034] The first rotation axis O1 is perpendicular to a mounting surface (not shown) of the fixed base 210. The second rotation axis O2 is perpendicular to the first rotation axis O1. The third rotation axis O3 is parallel to the second rotation axis O2. The fourth rotation axis O4 is perpendicular to the third rotation axis O3. The fifth rotation axis O5 is perpendicular to the fourth rotation axis O4. The sixth rotation axis O6 is perpendicular to the fifth rotation axis O5.

[0035] Furthermore, for these rotation axes, "perpendicular" includes not only the case where the angle between the two rotation axes is strictly 90°, but also the case where the angle between the two rotation axes deviates from 90° within a range of approximately ±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 tilted relative to the other within a range of approximately ±5°.

[0036] At the top of the arm 220, i.e., on the arm 226, a head unit 300 is mounted as an end effector.

[0037] The head unit 300 is a device comprising a head 310, an energy injection unit 330, and a distance measuring unit 360. The head 310 ejects ink, an example of a liquid, toward the workpiece W. The energy injection unit 330 is a hardening unit that hardens the ink ejected from the head 310 onto the workpiece W. The distance measuring unit 360 is a distance measuring unit that measures the distance from the head unit 300 to the workpiece W. In this embodiment, in addition to the head 310, the energy injection unit 330, and the distance measuring unit 360, the head unit 300 also includes a pressure regulating valve 320 that regulates the pressure of the ink supplied to the head 310. Since they are all fixed together on the arm 226, their relative positions and orientations are fixed.

[0038] The stereoscopic object printing apparatus 100 is capable of arbitrarily setting the positional relationship of the head unit 300 and the workpiece W by using a vertical multi-joint robot as a moving mechanism, and is further capable of performing printing on a desired surface of the workpiece W.

[0039] The ink is not particularly limited, and examples thereof include an aqueous ink in which a coloring material such as a dye or a pigment is dissolved in a water-based solvent, a curable ink using a curable resin such as an ultraviolet ray curable type, and a solvent-based ink in which a coloring material such as a dye or a pigment is dissolved in an organic solvent. Among them, a curable ink is preferably used. The curable ink is not particularly limited, and can be, for example, any one of a thermal curable type, a light curable type, a radiation ray curable type, an electron beam curable type, and the like, but is preferably a light curable type such as an ultraviolet ray curable type. In addition, the ink is not limited to a solution, and can be an ink in which a coloring material or the like is dispersed as a dispersed substance in a dispersion medium. Furthermore, the ink is not limited to an ink containing a coloring material, and can be an ink containing conductive particles such as metal particles for forming a wiring or the like as a dispersed substance.

[0040] Although not illustrated in Figure 1 , the head 310 has a head chip inside. The head chip has a piezoelectric element, a chamber that accommodates ink, and a nozzle N that communicates with the chamber. Here, the piezoelectric element is provided for each chamber, and ink is ejected from the nozzle N corresponding to the chamber by changing the pressure of the chamber. Such a head chip is obtained, for example, by adhering a plurality of substrates such as silicon substrates that are appropriately processed by etching or the like, with an adhesive or the like. The nozzle N is formed on a nozzle plate 312 described later. The nozzle plate 312 is one of the substrates that constitute the head chip. In addition, the piezoelectric element corresponds to the piezoelectric element 311 described later. Furthermore, as a driving element for ejecting ink from the nozzle N, a heater that heats the ink in the chamber can be used instead of the piezoelectric element. Figure 2

[0041] The pressure regulating valve 320 is a valve mechanism that opens and closes in accordance with the pressure of the ink inside the head 310. By this opening and closing, the pressure of the ink inside the head 310 is maintained at a negative pressure within a predetermined range. Therefore, stabilization of the meniscus of the ink formed on the nozzle N of the head 310 is achieved. As a result, it is possible to prevent the entry of air bubbles into the nozzle N, or the overflow of ink from the nozzle N.

[0042] In addition, although the number of the head 310 and the pressure regulating valve 320 that the head unit 300 has is one in the example illustrated in Figure 1 , the number is not limited to Figure 1 ​The example shown can also be two or more. Furthermore, the setting position of the pressure regulating valve 320 is not limited to the arm 226, and can be, for example, another arm or a fixed position with respect to the base 210.

[0043] The energy emitting section 330 emits energy such as light, heat, electron beams, or radioactive rays, which hardens the ink, depending on the kind of ink. For example, in the case of ink of an ultraviolet hardening type, the energy is ultraviolet rays. The energy emitting section 330 has a structure corresponding to the kind of energy. For example, in the case of the energy being ultraviolet rays, the energy emitting section 330 includes a light source such as a light emitting element, for example, an LED (light emitting diode), which emits ultraviolet rays. In addition, the energy emitting section 330 can have an optical member or the like, which adjusts the direction or range of emission of the energy, or the like.

[0044] The ink is hardened by irradiation of the energy emitted from the energy emitting section 330. Here, "hardening" is a concept including a case where a hardenable resin such as a thermally hardenable resin or a light hardenable resin is hardened by a reaction such as polymerization, a case where a solid derived from a solute is obtained by removing a solvent from a solution, or a case where a solid derived from a dispersed substance is obtained by removing a dispersing agent from a dispersion liquid.

[0045] Here, the energy emitting section 330 is preferably capable of adjusting the intensity of the energy emitted. In this case, by reducing the intensity of the energy at the time of the printing operation described later, it is possible to reduce clogging of the nozzles, and by increasing the intensity of the energy at the time of the hardening operation described later, it is possible to shorten the time required for hardening or solidification of the ink.

[0046] The distance measuring section 360 measures the distance between the distance measuring section 360 and the workpiece W by emitting an electromagnetic wave, an acoustic wave, or the like toward the workpiece W and detecting the electromagnetic wave, the acoustic wave, or the like reflected by the workpiece W. For example, a laser displacement meter or an ultrasonic sensor can be used as the distance measuring section 360. As another example of the distance measuring section 360, a three-dimensional vision camera can also be used.

[0047] 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.

[0048] The liquid storage section 410 is a container that stores ink. The liquid storage section 410 is, for example, an ink bag that is bag-shaped formed by a thin film having flexibility.

[0049] In Figure 1In the example shown, the liquid reservoir 410 is fixed to a wall, ceiling, or column in a manner that always positions it further Z1 than the head 310. That is, the liquid reservoir 410 is located higher in the vertical direction than the moving area of ​​the head 310. Therefore, even without using a pump or similar mechanism, ink can be supplied from the liquid reservoir 410 to the head 310 at a predetermined pressure.

[0050] The supply channel 420 is a channel for supplying ink from the liquid reservoir 410 to the head 310. A pressure regulating valve 320 is provided midway through the supply channel 420. Therefore, even if the positional relationship between the head 310 and the liquid reservoir 410 changes, the pressure fluctuation of the ink in the head 310 can be reduced.

[0051] Controller 600 is a robot controller that controls the drive of robot 200. Regarding the functions of controller 600, in... Figure 1 Other structural elements not shown in the diagram and their connections to the controller 600 will be described below.

[0052] 1-2. Electrical Structure of a Three-Dimensional Printing Apparatus

[0053] Figure 2 This is a block diagram illustrating the electrical structure of the three-dimensional printing apparatus 100 according to the first embodiment. Figure 2 The diagram shows the electrical structural elements within the structural elements of the three-dimensional printing apparatus 100. Furthermore, in... Figure 2 The diagram shows an arm drive mechanism 240 including encoders 241_1 to 241_6. The arm drive mechanism 240 is an assembly of the aforementioned drive mechanisms that actuate joints 230_1 to 230_6. Encoders 241_1 to 241_6 are arranged in a manner corresponding to joints 230_1 to 230_6, and the rotation angle and other actuation quantities of joints 230_1 to 230_6 are measured. Furthermore, in the following text, each encoder 241_1 to 241_6 is sometimes referred to as encoder 241.

[0054] like Figure 2 As shown, the stereolithography printing apparatus 100, in addition to the robot 200, head unit 300, and controller 600 described above, also includes 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 going through the computer 700, and can directly transmit the signal D3 described later. Additionally, the electrical structural elements can be appropriately separated, partially included in other structural elements, or integrally formed with other structural elements.

[0055] 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 action of the head 310 with the action of the robot 200. The controller 600 has a storage circuit 610 and a processing circuit 620.

[0056] The storage circuit 610 stores various programs executed by the processing circuit 620 and various data processed by the processing circuit 620.

[0057] The path information Db is stored in the storage circuit 610. Here, the path information Db is information indicating a path through which the head unit 300 should move. For example, the path information Db is indicated using coordinate values of the basic coordinate system. The path information Db is determined based on workpiece information indicating the position and shape of the workpiece W. The workpiece information can be obtained by establishing a correspondence relationship between information such as CAD (computer-aided design) data indicating the three-dimensional shape of the workpiece W and the above-described basic coordinate system. The above-described path information Db is input from the computer 700 to the storage circuit 610.

[0058] The processing circuit 620 controls the actions of the joint sections 230_1 to 230_6 based on the path information Db and generates the signal D3. Specifically, the processing circuit 620 performs an operation of converting the path information Db into action amounts such as the rotation angles and rotation speeds of the joint sections 230_1 to 230_6, that is, inverse kinematics calculation. 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 in such a manner that the actual rotation angles and rotation speeds and the like of the joint sections 230_1 to 230_6 become the above-described operation results. The control signals Sk_1 to Sk_6 correspond to the joint sections 230_1 to 230_6 and control the driving of the motors provided on the corresponding joint sections 230. In addition, 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 will be sometimes referred to as the output D1.

[0059] Further, the processing circuit 620 generates the 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 a timing at which the output D1 from one of the encoders 241_1 to 241_6 becomes a predetermined value.

[0060] The control module 500 is a circuit that controls the ejection operation of the head 310 based on the signal D3 output from the controller 600 and the print data Img from the computer 700. The control module 500 has a timing signal generating circuit 510, a power supply circuit 520, a control circuit 530, and a drive signal generating circuit 540.

[0061] The timing signal generating circuit 510 generates a timing signal PTS with the signal D3 as a trigger. The timing signal PTS is a signal that specifies the timing of the ejection operation of the head 310, and is generated by a timer included in the timing signal generating circuit 510.

[0062] The power supply circuit 520 receives the supply of electric power from a commercial power supply not shown, and generates predetermined various electric potentials. The generated various electric potentials are supplied to each part of the three-dimensional object printing apparatus 100 as appropriate. For example, the power supply circuit 520 generates a power supply potential VHV and a bias potential VBS. The bias potential VBS is supplied to the head unit 300. Further, the power supply potential VHV is supplied to the drive signal generating circuit 540.

[0063] The control circuit 530 generates a control signal SI, a waveform specifying signal dCom, a latch signal LAT, a clock signal CLK, and a switching signal CNG based on the timing signal PTS. These signals are synchronized with the timing signal PTS. The waveform specifying signal dCom among these signals is input to the drive signal generating circuit 540, and the other signals are input to the switch circuit 340 of the head unit 300.

[0064] The control signal SI is a digital signal that is used to specify the operating state of the piezoelectric element 311 possessed by the head 310. The waveform specifying signal dCom is a digital signal that specifies the waveform of the drive signal Com described later. The latch signal LAT and the switching signal CNG are used in conjunction with the control signal SI, and specify the ejection timing of the ink from the nozzle N. The clock signal CLK is a clock signal that becomes a reference synchronized with the timing signal PTS.

[0065] The drive signal generation circuit 540 is a circuit that generates a drive signal Com for driving each piezoelectric element 311 possessed by the head 310. Specifically, the drive signal generation circuit 540 has, for example, a DA conversion circuit and an amplification circuit. In the drive signal generation circuit 540, the waveform designation signal dCom from the control circuit 530 is converted from a digital signal to an analog signal by the DA conversion circuit, and the analog signal is amplified by the amplification circuit using the power supply potential VHV from the power supply circuit 520, thereby generating the drive signal Com. Here, the signal of the waveform included in the drive signal Com, which is actually supplied to the piezoelectric element 311, is a drive pulse PD. The drive pulse PD is supplied from the drive signal generation circuit 540 to the piezoelectric element 311 via the switching circuit 340. The switching 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.

[0066] The computer 700 has a function of supplying the path information Db to the controller 600 and a function of supplying the print data Img to the control module 500. Further, the computer 700 of the present embodiment is electrically connected to the energy emitting portion 330 described above, and outputs a signal D2 that controls driving of the energy emitting portion 330 based on signals from the controller 600 and the control module 500. Further, the computer 700 of the present embodiment is electrically connected to the distance measuring portion 360 described above, and the distance measuring portion 360 outputs the distance information D4 to the computer 700. Alternatively, the controller 600 and the distance measuring portion 360 can be directly connected. The functions of the energy emitting portion 330 and the distance measuring portion 360 will be described below.

[0067] 1-3. Head unit

[0068] Figure 3 A perspective view showing the outline structure of the head unit 300 in the first embodiment.

[0069] The following description is appropriately made using the a-axis, the b-axis, and the c-axis that cross each other. Further, one direction along the a-axis is referred to as an al direction, and a direction opposite to the al direction is referred to as an a2 direction. Similarly, directions opposite to each other along the b-axis are referred to as a bl direction and a b2 direction. Further, directions opposite to each other along the c-axis are referred to as a cl direction and a c2 direction.

[0070] Here, the a-axis, the b-axis, and the c-axis are coordinate axes of a tool coordinate system provided in the head unit 300, and the relative positions and the posture of the above-described X-axis, Y-axis, and Z-axis are changed by the above-described operation of the robot 200. In the present embodiment, the a-axis, the b-axis, and the c-axis are set so that the a-axis is parallel to the X-axis, the b-axis is parallel to the Y-axis, and the c-axis is parallel to the Z-axis. Figure 3In the example shown, the c-axis is an axis parallel to the sixth rotation axis O6 described above. In addition, while the a-axis, the b-axis, and the c-axis are typically orthogonal to each other, they are not limited thereto, and may, for example, intersect at an angle in a range of 80° or more and 100° or less.

[0071] As described above, the head unit 300 has the head 310, the pressure regulating valve 320, the energy emission portion 330, and the distance measurement portion 360. They are supported by the support body 350 shown by a broken line in Figure 3

[0072] The support body 350 is composed of, for example, a metal material or the like, and is a substantially rigid body. In addition, while the support body 350 is in a flat box shape in Figure 3

[0073] The support body 350 described above is mounted on the tip end of the arm 220 described above, that is, the arm 226. Therefore, the positional relationship of the head 310, the pressure regulating valve 320, the energy emission portion 330, and the distance measurement portion 360 with the arm 226 is fixed.

[0074] In the example shown, the pressure regulating valve 320 is located in the c1 direction with respect to the head 310. The energy emission portion 330 is located in the a2 direction with respect to the head 310. The distance measurement portion 360 is located in the a1 direction with respect to the head 310. In addition, the detailed positional relationship of the head 310, the energy emission portion 330, and the distance measurement portion 360 will be described below. Figure 3 The supply flow passage 420 is divided into an upstream flow passage 421 and a downstream flow passage 422 by the pressure regulating valve 320. That is, the supply flow passage 420 has the upstream flow passage 421 that communicates the liquid reservoir 410 with the pressure regulating valve 320, and the downstream flow passage 422 that communicates the pressure regulating valve 320 with the head 310.

[0075]

[0076] A plan view showing the structure when the head unit 300 in the present embodiment is viewed in the c1 direction. Figure 4 As described above, the head unit 300 has the head 310, the pressure regulating valve 320, the energy emission portion 330, and the distance measurement portion 360. They are supported by the support body 350 shown by a broken line in

[0077] Figure 3 Figure 4 ​​​​As shown, in the present embodiment, the head 310 includes a nozzle plate 312, a frame portion 313, and a cover member 314. The nozzle plate 312 is a plate-shaped member that constitutes a portion of the head chip described above, and is formed of silicon (Si) or a metal, and is provided in a manner that a plurality of nozzles N are opened. The frame portion 313 is a member that holds the head chip, and is formed of a resin or a metal, and has an internal flow path that supplies ink to the head chip provided inside. The cover member 314 is a metal member formed in a manner that surrounds the nozzle plate 312, and protects the nozzle plate 312.

[0078] Here, the head 310 has an ejection face Fl on which the nozzles N are formed. The ejection face Fl is a surface that constitutes a portion of the nozzle plate 312 and its periphery, and is a face that can be visually confirmed when the head 310 is observed from the ink ejection direction side. The ink ejection direction in the present embodiment, that is, the direction in which the head 310 ejects ink, is the c2 direction, and observing from the ink ejection direction side means observing the head 310 in the cl direction. Here, the portion that constitutes the nozzle plate 312 and its periphery means the portion on the c2 direction side on which the nozzle plate 312 is provided when the head 310 is divided in half along the c-axis direction.

[0079] The ejection face Fl can also include a plurality of faces. The ejection face Fl in the present embodiment includes a nozzle face Fll and a cover face F12. The nozzle face Fll is a face of the nozzle plate 312 that has a direction along the c-axis as a normal direction, and ink is ejected from a plurality of nozzles N provided on the nozzle face Fll toward the c2 direction. The cover face F12 is a face that has a direction along the c-axis as a normal direction, and the nozzle face Fll is provided at an opening provided on the cover face F12.

[0080] Here, the positions of the nozzle face Fll and the cover face F12 in the c-axis direction can also be different. Although omitted in Figure 3 the present embodiment, the cover face F12 is located slightly more on the c2 direction side than the nozzle face Fll. According to this positional relationship, the nozzle face Fll is difficult to contact an object, and thus the nozzle face Fll is protected.

[0081] Although the members that constitute the ejection face Fl are the nozzle plate 312 and the cover member 314 in the present embodiment, the members that constitute the ejection face Fl are not limited thereto. For example, in the case where the frame portion 313 is larger than the cover member 314 in the al direction or the a2 direction, the portion that can be visually confirmed when the frame portion 313 is observed in the cl direction is included in the ejection face Fl.

[0082] The plurality of nozzles N are divided into a first nozzle row La and a second nozzle row Lb arranged at intervals from each other in the direction along the a-axis. The first nozzle row La and the second nozzle row Lb are each an example of a "nozzle row" and are each a collection of a plurality of nozzles N arranged in a linear shape in the direction along the b-axis. Therefore, in the following description, the b-axis is sometimes referred to as a nozzle row axis. Here, the elements associated with each nozzle N of the first nozzle row La and the elements associated with each nozzle N of the second nozzle row Lb are structures that are substantially symmetrical to each other in the direction along the a-axis.

[0083] However, the positions of the plurality of nozzles N in the first nozzle row La and the plurality of nozzles N in the second nozzle row Lb in the direction along the b-axis can be identical to each other or different from each other. Furthermore, the elements associated with each nozzle N of one of the first nozzle row La and the second nozzle row Lb can be omitted. Hereinafter, a structure in which the positions of the plurality of nozzles N in the first nozzle row La and the plurality of nozzles N in the second nozzle row Lb in the direction along the b-axis are identical to each other is exemplified.

[0084] The energy emitting portion 330 includes a window portion 331 and a frame portion 332. The frame portion 332 is a box-shaped member formed of metal or the like. The window portion 331 is a member formed of transparent glass or the like and is provided on the c2-direction side face of the frame portion 332.

[0085] Here, the energy emitting portion 330 has an emission face F2 that emits energy. The emission face F2 is a surface of a portion constituting the window portion 331 and its periphery and is a face that can be visually confirmed when the energy emitting portion 330 is viewed from the ejection direction side. Here, the portion constituting the window portion 331 and its periphery refers to a portion on the c2-direction side provided with the window portion 331 when the energy emitting portion 330 is divided in half along the c-axis direction.

[0086] The emission face F2 can also include a plurality of faces. The emission face F2 in the present embodiment is constituted by a window face F21 and a frame face F22. The window face F21 is a face of the window portion 331 exposed to the outside. The frame face F22 is a face of the frame portion 332 that can be visually confirmed when the frame portion 332 is viewed in the c1-direction.

[0087] The energy emitting portion 330 in the present embodiment is an ultraviolet lamp. A UV-LED (Ultraviolet light emitting diode) and a reflector, which are not shown, are arranged inside the frame portion 332, and ultraviolet light emitted from the UV-LED is emitted from the window face F21 in the c2-direction. That is, the c2-direction is the emission direction of the energy. In addition, the ultraviolet lamp generates heat at the time of light emission due to the resistance of the electronic components and the wiring provided inside.

[0088] In the present 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. As other shapes of the window portion 331, for example, it can be a concave lens shape or a convex lens shape, in which case the window surface F21 is curved. The shape of the frame portion 332 is also not similarly limited.

[0089] In addition, the positions of the window surface F21 and the frame surface F22 in the c-axis direction can also be different. Although this is omitted in Figure 3 the frame surface F22 is located slightly more on the c2 direction side than the window surface F21. According to this positional relationship, the window surface F21 is difficult to contact an object, thereby protecting the window surface F21.

[0090] The distance measuring portion 360 includes a window portion 361 and a frame portion 362. The frame portion 362 is a box-shaped member formed of metal, resin, or the like. The window portion 361 is a member formed of transparent glass, resin, or the like, and is provided on the c2 direction side surface of the frame portion 362.

[0091] Here, the distance measuring portion 360 has a measurement surface F3 that measures the relative distance from the workpiece W. The measurement surface F3 is a surface that constitutes a portion of the window portion 361 and its periphery, and is a surface that can be visually confirmed when the distance measuring portion 360 is viewed from the ejection direction side described above. Here, the portion that constitutes 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 measuring portion 360 is divided in half along the c-axis direction.

[0092] The measurement surface F3 can also include a plurality of surfaces. The measurement surface F3 is constituted by a window surface F31 and a frame surface F32. The window surface F31 is a surface of the window portion 361 that is exposed to the outside. The frame surface F32 is a surface of the frame portion 362 that can be visually confirmed when the frame portion 362 is viewed in the c1 direction.

[0093] The distance measuring portion 360 in the present embodiment is a laser displacement meter. A laser light source and a light receiving element, which are not shown, are disposed inside the frame portion 362. Laser light generated from the laser light source is emitted from the window portion 361, is reflected by the surface of an object, is again emitted from the window portion 361, and is detected by the light receiving element. In this way, the laser displacement meter can measure the distance from the surface of the workpiece W in the direction of the distance measuring portion 360 along the c-axis. That is, the c2 direction is the measurement direction of the distance measuring portion 360. In addition, the distance measuring portion 360 generates heat at the time of measurement due to the resistance of the electronic components and wiring provided inside.

[0094] In the present 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. As other shapes of the window portion 361, for example, a concave lens shape or a convex lens shape or the like can be used, in which case the window surface F31 is curved. The shape of the frame portion 362 is also not limited in the same way. In addition, the window portion 361 is sometimes provided in multiple numbers.

[0095] In addition, the positions of the window surface F31 and the frame surface F32 in the c-axis direction can also be different. Although this is omitted in Figure 3 , the frame surface F32 is located slightly more on the c2 direction side than the window surface F31. According to this positional relationship, the window surface F31 is difficult to contact an object, thereby protecting the window surface F21.

[0096] Next, the positional relationship of the ejection surface F1 of the head 310, the emission surface F2 of the energy emission portion 330, and the measurement surface F3 of the distance measurement portion 360 will be described.

[0097] Figure 5 A side view showing the positional relationship of the head unit 300 according to the present embodiment and the robot 200 is shown, and the head 310, the energy emission portion 330, the distance measurement portion 360, and the support body 350 are shown as viewed in the b-axis direction. As described above, the support body 350 of the head unit 300 is mounted on the tip of the arm 220 described above, that is, the arm 226.

[0098] As shown in Figure 3 and Figure 5 , the ejection surface F1 of the head 310 is located on the c2 direction side than the emission surface F2 of the energy emission portion 330. In other words, the ejection surface F1 is located on the ink ejection direction side than the emission surface F2. In addition, the ejection surface F1 of the head 310 is located on the c2 direction side than the measurement surface F3 of the distance measurement portion 360. In other words, the ejection surface F1 is located on the ink ejection direction side than the measurement surface F3.

[0099] In addition, the emission surface F2 is located between the measurement surface F3 and the ejection surface F1 in the c-axis direction. In addition, 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.

[0100] In Figure 5In this embodiment, the fifth rotation axis O5, which serves as the rotation axis of the joint 230_5 of the arm 220, and the nozzle array axis of the head 310 are substantially parallel. That is, the fifth rotation axis O5 is parallel to the b-axis. This positional relationship between the arm 220 and the head 310 allows for adjustment of rotation around the sixth rotation axis O6 at the joint 230_6, which causes the arm 226 to rotate relative to the arm 225. Here, in this embodiment, the nozzle array axis is formed along the b-axis, and the rotation axis of the joint 230_6 is parallel to the c-axis.

[0101] like Figure 5 As shown, when observed along the nozzle array axis, when the distance between the fifth rotation axis O5 (parallel to the nozzle array axis) and the end point F1a of the ejection surface F1 is set to R, the ejection surface F2 is located inside an imaginary circle C with the fifth rotation axis O5 as its central axis and a radius of R. Similarly, the measuring surface F3 is also located inside the aforementioned imaginary circle C. Here, the end point F1a of the ejection surface F1 refers to the portion of the ejection surface F1 furthest from the fifth rotation axis O5 when observing the head 310 along the nozzle array axis. In other words, when the fifth rotation axis O5 is taken as the starting point, the distance to end point F1a is greater than the distance to the end point of the ejection surface F2 furthest from the fifth rotation axis O5 and the distance to the end point of the measuring surface F3 furthest from the fifth rotation axis O5.

[0102] The energy emission unit 330 and the distance measuring unit 360 can be configured such that the emission surface F2 and the measuring surface F3 are located inside the imaginary circle C, and are not limited to... Figure 5 The position of the energy ejection unit 330 can be adjusted according to its size, such that the ejection surface F2 is located inside the imaginary circle C. For example, it can be positioned in... Figure 5 The position is indicated by the dashed line at 330a. The same applies to the distance measuring unit 360.

[0103] Among the multiple rotation axes of the arm 220 of robot 200, at least one rotation axis is parallel to the nozzle column axis, and the fifth rotation axis O5 is the rotation axis closest to the head unit 300. In the following description, the rotation axis satisfying this condition will sometimes be referred to as the central rotation axis. That is, the imaginary circle C is formed with the central rotation axis as its central axis. Furthermore, "closest" as used here refers to its order in the connection relationship of the arm 220.

[0104] Alternatively, the energy emission section 330 can be tilted. For example, it can be configured as follows: Figure 5 As shown in the dotted line 330b, the energy emission section 330 is tilted so that the emission surface F2 faces the opposite side of the side where the head 310 is located.

[0105] As shown in FIG. 3, the head unit 300 is observed in the c1 direction, the ejection face F2 is located between the measurement face F3 and the ejection face F1 in the a-axis direction, and the width W330 of the ejection face F2 in the a-axis direction is greater than the width W310 of the ejection face F1 in the a-axis direction. Figure 4 As shown in FIG. 3, the head unit 300 is observed in the c1 direction, the ejection face F2 is located between the measurement face F3 and the ejection face F1 in the a-axis direction, and the width W330 of the ejection face F2 in the a-axis direction is greater than the width W310 of the ejection face F1 in the a-axis direction.

[0106] As shown in FIG. 3, the head unit 300 is observed in the c1 direction, the ejection face F2 is located between the measurement face F3 and the ejection face F1 in the a-axis direction, and the width W330 of the ejection face F2 in the a-axis direction is greater than the width W310 of the ejection face F1 in the a-axis direction. Figure 3 As shown in FIG. 3, the head unit 300 is observed in the c1 direction, the ejection face F2 is located between the measurement face F3 and the ejection face F1 in the a-axis direction, and the width W330 of the ejection face F2 in the a-axis direction is greater than the width W310 of the ejection face F1 in the a-axis direction.

[0107] As shown in FIG. 3, the head unit 300 is observed in the c1 direction, the ejection face F2 is located between the measurement face F3 and the ejection face F1 in the a-axis direction, and the width W330 of the ejection face F2 in the a-axis direction is greater than the width W310 of the ejection face F1 in the a-axis direction. Figure 4 As shown in FIG. 3, the head unit 300 is observed in the c1 direction, the ejection face F2 is located between the measurement face F3 and the ejection face F1 in the a-axis direction, and the width W330 of the ejection face F2 in the a-axis direction is greater than the width W310 of the ejection face F1 in the a-axis direction. Figure 4 As shown in FIG. 3, the head unit 300 is observed in the c1 direction, the ejection face F2 is located between the measurement face F3 and the ejection face F1 in the a-axis direction, and the width W330 of the ejection face F2 in the a-axis direction is greater than the width W310 of the ejection face F1 in the a-axis direction.

[0108] As shown in FIG. 3, the head unit 300 is observed in the c1 direction, the ejection face F2 is located between the measurement face F3 and the ejection face F1 in the a-axis direction, and the width W330 of the ejection face F2 in the a-axis direction is greater than the width W310 of the ejection face F1 in the a-axis direction. Figure 4 As shown in FIG. 3, the head unit 300 is observed in the c1 direction, the ejection face F2 is located between the measurement face F3 and the ejection face F1 in the a-axis direction, and the width W330 of the ejection face F2 in the a-axis direction is greater than the width W310 of the ejection face F1 in the a-axis direction.

[0109] AsFigure 4 As shown, when observing the head unit 300 along the c1 direction, the end of the measuring surface F3 on the b1 direction side does not protrude in the b1 direction compared to the end of the ejection surface F1 on the b1 direction side. Similarly, the end of the measuring surface F3 on the b2 direction side does not protrude in the b2 direction compared to the end of the ejection surface F1 on the b2 direction side. That is, in this embodiment, the position of the measuring surface F3 in the b-axis direction is between the end of the ejection surface F1 on the b1 direction side and the end on the b2 direction side. However, the end of the measuring surface F3 on the b2 direction side may also protrude in the b2 direction compared to the end of the ejection surface F1 on the b2 direction side.

[0110] 1-4. Operation of the 3D printing apparatus and 3D printing method

[0111] Figure 6 This is a flowchart illustrating the process of the three-dimensional printing method according to the first embodiment. This three-dimensional printing method is performed using the three-dimensional printing apparatus 100 described above. Figure 6 As shown, the stereoscopic printing apparatus 100 sequentially performs the step of setting the path S110, the step of performing the printing action S120, and the step of performing the hardening action S130.

[0112] Figures 7A to 7C This diagram illustrates the path setting and printing operation in the first embodiment, and is based on... Figures 7A to 7C The position and posture of the head unit 300 are shown in sequence corresponding to the passage of time. In this embodiment, the workpiece W has a concave curved surface, namely surface WF, and surface WF is printed by the stereolithography printing apparatus 100. Figures 7A to 7C The dashed arrow marks represent path RU, and the arrow marks indicate the direction of movement of head unit 300 in path RU. That is, the direction of movement is the direction in which head unit 300 moves relative to workpiece W, and this movement is implemented by robot 200.

[0113] In step S110, a path RU is set as a path through which a representative point inside or in the vicinity of the head unit 300 should move, based on the work information indicating the position and shape of the work W. This representative point in the present embodiment is set on the ejection face Fl, and information about the posture that the ejection face Fl should take is also included in the path RU. In addition, this representative point corresponds to a TCP (Tool Center Point) in teaching of a robot. The path RU and its direction are preferably set so as to follow the face WF, and the posture of the ejection face Fl and the moving direction at the middle of the path RU are changed in correspondence with the face WF at all times. In this way, by setting the path RU, the above-described path information Db is generated by the computer 700. In the present embodiment, the path RU is set in such a manner that the head unit 300 roughly scans the face WF in the direction of Xl.

[0114] Here, the distance between the path RU and the face WF is substantially fixed, and the angle between the normal line of the ejection face Fl of the head 310 and the face WF is substantially fixed. Therefore, the distance L between the ejection face Fl of the head 310 in the normal line direction and the face WF is substantially fixed across the entire region of the path RU. Therefore, it is possible to reduce the error of the landing position of the ink from the head 310 to the face WF. In addition, in the example shown in the figure, the normal line of the ejection face Fl is orthogonal or substantially orthogonal to the face WF. Therefore, it is easier to improve the print quality compared to the case where the normal line of the ejection face Fl is inclined with respect to the face WF. Figures 7A to 7C

[0115] In step S120, printing is performed by causing the head 310 to eject ink toward the face WF of the work W while the head unit 300 is moving along the path RU. At this time, the al direction in the above-described tool coordinate system is oriented in the direction of the path RU. That is, the head 310 moves in a direction orthogonal to both the nozzle row axis and the ejection direction. Also, the distance measuring section 360 is located in front of the head 310 in the moving direction. In addition, the head 310 is located in front of the energy emitting section 330 in the moving direction. In other words, in the printing operation, the measurement face F3 is located on the moving direction side from the ejection face Fl. In addition, the ejection face Fl is located on the moving direction side from the emission face F2.

[0116] In step S120, energy can also be emitted from the energy emitting section 330 while the head unit 300 is moving and the ink is being ejected by the head 310. That is, in the present embodiment, ultraviolet rays can also be irradiated toward the face WF, thereby hardening the ink landed on the face WF.

[0117] ​In step S120, the distance between the head unit 300 and the surface WF is measured by the distance measuring section 360 while the head unit 300 is moved and the ink is ejected by the head 310. That is, in the present embodiment, the distance between the head unit 300 and the surface WF is measured by the distance measuring section 360, and the robot 200 is controlled in such a manner that the above-mentioned distance L is kept constant based on the signal of the distance measuring section 360.

[0118] In step S130, a hardening operation of hardening the ink that is dropped on the surface WF in step S120 is performed. In addition, in the case where the energy is emitted from the energy emitter 330 and the ink is sufficiently hardened and fixed on the surface WF as described above in step S120, step S130 can be omitted. In the hardening operation of step S130, the robot 200 is operated, and the energy is emitted from the energy emitter 330 while the surface WF is scanned with the energy emitter 330. The path in the hardening operation can be the same as or different from the path RU in the printing operation. Furthermore, in step S130, the hardening operation can be performed using a not-illustrated hardening unit that is provided separately from the energy emitter 330.

[0119] The above-described steps S110 to S130 are performed by the stereoscopic object printing apparatus 100, and thus the printing by the ink is completed on the surface WF of the workpiece W.

[0120] Although the case where the head unit 300 has both the energy emitter 330 and the distance measuring section 360 is described in the present embodiment, one of them can be omitted. For example, in the case where the curable ink is not used, the energy emitter 330 can not be provided. For example, in the case where the operation path of the robot 200 is determined in advance, the distance measuring section 360 can not be provided.

[0121] In the three-dimensional object printing apparatus 100 in the present embodiment, the ejection face Fl of the head 310 is located on the c2 direction side compared to the emission face F2 of the energy emission section 330. In other words, the ejection face Fl is located on the side of the ink ejection direction compared to the emission face F2. Therefore, when the relative position and posture of the ejection face Fl with respect to the workpiece W are set to a desired position and posture, it is possible to prevent contact of the emission face F2 with the workpiece W. In particular, when the ejection face Fl and the face WF of the workpiece W are brought close to each other while being opposed to each other, it is possible to bring the ejection face Fl closer to the face WF in the ejection direction compared to the emission face F2. Therefore, it is possible to improve the accuracy of the position at which the ink ejected from the nozzle N of the head 310 lands on the face WF, and thus it is possible to improve the printing quality. Furthermore, since the head unit 300 includes the energy emission section 330 having the emission face F2, it is possible to immediately irradiate energy to the ink that lands on the face WF, and harden the ink.

[0122] In the three-dimensional object printing apparatus 100 in the present embodiment, in the head unit 300, the positional relationship of the ejection face Fl and the emission face F2 with respect to each other is fixed. Therefore, for example, compared to a structure of a head unit in which the positional relationship of the ejection face Fl and the emission face F2 is variable using a linear actuator or the like, it becomes a simple structure, and control also becomes easy.

[0123] In the three-dimensional object printing apparatus 100 in the present embodiment, in a state in which the fifth rotation axis O5 that is the center rotation axis and the nozzle row axis are parallel to each other, when the end portion Fla of the ejection face Fl that is farthest from the fifth rotation axis O5 is set as R, the emission face F2 and the measurement face F3 are located inside an imaginary circle C having the fifth rotation axis O5 as the center and a radius of R when the head 310 is observed in the direction of the nozzle row axis. Therefore, in a printing posture in which the ejection face Fl and the workpiece W are opposed and brought close, when the head unit 300 is rotated around the fifth rotation axis O5, it is possible to prevent the energy emission section 330 and the distance measurement section 360 from interfering with the workpiece W.

[0124] In the three-dimensional object printing apparatus 100 of the present embodiment, the ejection face Fl of the head 310 is located on the c2 direction side compared to the measurement face F3 of the distance measuring portion 360. In other words, the ejection face Fl is located on the side of the ejection direction of the ink compared to the measurement face F3. Therefore, when the relative position and posture of the ejection face Fl with respect to the workpiece W are set to the desired position and posture, it is possible to prevent contact of the measurement face F3 with the workpiece W. In particular, when the ejection face Fl and the face WF of the workpiece W are opposed to each other and are close to each other, it is possible to make the ejection face Fl closer to the face WF in the ejection direction compared to the measurement face F3. Therefore, it is possible to improve the accuracy of the position at which the ink ejected from the nozzle N of the head 310 lands on the face WF, and thus it is possible to improve the printing quality. Furthermore, since the head unit 300 includes the distance measuring unit having the measurement face F3, it is possible to accurately measure the distance between the head unit 300 and the workpiece W.

[0125] In the three-dimensional object printing apparatus 100 of the present embodiment, in the head unit 300, the positional relationship between the ejection face Fl and the measurement face F3 is fixed. Therefore, for example, compared to a head unit in which the positional relationship between the ejection face Fl and the measurement face F3 is variable using a linear actuator or the like, a simple structure is obtained, and control becomes easy.

[0126] In the three-dimensional object printing apparatus 100 of the present embodiment, in the ejection direction, the emission face F2 is located between the measurement face F3 and the ejection face Fl. Therefore, the energy emitted from the emission face F2 is irradiated to the ink landing on the face WF of the workpiece W while maintaining sufficient intensity, and thus it is possible to efficiently harden the ink. In other words, by making the distance between the face WF and the emission face F2 close, it is possible to suppress the attenuation of the energy emitted from the emission face F2 before reaching the face WF compared to the case in which the distance is far. Furthermore, it is possible to reduce the case in which the entire head unit 300 is made to be far from the workpiece W in order to prevent contact of the measurement face F3 with the workpiece W. Therefore, it is possible to improve the accuracy of the position at which the ink ejected from the nozzle N of the head 310 lands on the face WF, and thus it is possible to improve the printing quality. Furthermore, since the energy emitted from the emission face F2 is irradiated to the ink landing on the face WF while maintaining sufficient intensity, it is possible to efficiently harden the ink.

[0127] In the stereolithography printing apparatus 100 of this embodiment, the distance between the injection surface F2 and the ejection surface F1 in the ejection direction is shorter than the distance between the measuring surface F3 and the ejection surface F1. Therefore, when the head unit 300 is brought close to the workpiece W, the distances between the ejection surface F1 and the surface WF, and between the injection surface F2 and the surface WF, are narrower compared to the distances between the measuring surface F3 and the surface WF. Furthermore, the need to move the head unit 300 away from the workpiece W as a whole to prevent the measuring surface F3 from contacting the workpiece W is reduced. Therefore, the accuracy of the position of the ink ejected from the nozzle N of the head 310 landing on the surface WF can be improved, thereby improving the printing quality. In addition, since the energy emitted from the injection surface F2 is irradiated onto the ink landing on the surface WF with sufficient intensity, the ink can be effectively hardened.

[0128] In the printing operation, in the three-dimensional printing apparatus 100, multiple nozzles N are arranged on the ejection surface F1 along the nozzle array axis. In the a-axis direction, which is orthogonal to both the nozzle array axis and the ejection direction, the ejection surface F1 is located between the injection surface F2 and the measurement surface F3. Furthermore, the operation of moving the head unit 300 via the robot 200, the operation of ejecting ink from the head 310 onto the surface WF of the workpiece W, and the operation of ejecting energy from the energy ejection unit 330 can be performed simultaneously.

[0129] like Figures 7A to 7C As shown, the three-dimensional printing apparatus 100 moves the head unit 300 in the a-axis direction, which is orthogonal to both the nozzle row axis and the ejection direction. Since the measuring surface F3 is located on the moving direction side compared to the ejection surface F1 during this printing operation, the measuring surface F3 scans the area of ​​the surface WF first compared to the ejection surface F1. Therefore, the distance between this area and the head unit 300 can be measured by first scanning the area of ​​the surface WF with the measuring surface F3, and then the area of ​​the surface WF can be scanned with the ejection surface F1, and ink can be ejected from the head 310. At this time, control can be performed by keeping the distance L constant based on the distance measurement result. Furthermore, it is possible to prevent the area of ​​the surface WF from contacting the ejection surface F1. In addition, distance measurement and ink ejection can be completed through a series of actions.

[0130] like Figures 7A to 7CAs illustrated, the three-dimensional object printing apparatus 100 moves the head unit 300 in the a-axis direction orthogonal to both the nozzle row axis and the ejection direction. Since the ejection face Fl is located on the moving direction side compared to the emission face F2 at the time of the printing operation, the ejection face Fl scans the area on the face WF first compared to the emission face F2. Therefore, it is possible to first eject ink from the head 310 for the area of the face WF, and next to bring the emission face F2 close to the area of the workpiece W on which the ink is ejected. Therefore, it is possible to complete the ejection of ink and the hardening of the ink by the irradiation energy by a series of operations.

[0131] When the head unit 300 is observed 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 measuring section 360 and the energy emission section 330, which generate heat by driving. Therefore, heat generated from the distance measuring section 360 and the energy emission section 330 is conducted to the downstream flow path 422 located therebetween, so that the ink in the flow path is heated, thereby reducing the viscosity of the ink. Therefore, it is possible to suppress the occurrence of ejection failure due to clogging of ink in the head 310 and the downstream flow path 422.

[0132] In the three-dimensional object printing apparatus 100 of the present embodiment, the width W310 of the ejection face Fl in the a-axis direction orthogonal to both the nozzle row axis and the ejection direction is narrower than the width W330 of the emission face F2 in the a-axis direction. Therefore, for example, it is also easy to bring the ejection face Fl close to a recess or the like of the workpiece W. Further, since the width W330 of the emission face F2 in the moving direction is wide, the emission face F2 takes a long time to scan the face WF on the workpiece W at the time of the printing operation. Therefore, it is possible to irradiate sufficient energy to the ink ejected on the face WF after the ink is ejected from the head 310 to harden the ink.

[0133] In the three-dimensional object printing apparatus 100 of the present embodiment, the energy emission section 330 can also be inclinedly arranged in a manner that the emission face F2 faces the side opposite to the side where the head 310 is located. According to this three-dimensional object printing apparatus 100, the energy emitted from the emission face F2 is difficult to be emitted to the ejection face Fl. Therefore, it is possible to prevent the occurrence of ejection failure in which the energy is irradiated to the ink adhering to the ejection face Fl or the ink forming a meniscus in the nozzle N to harden the ink.

[0134] 2. Second Embodiment

[0135] Hereinafter, a second embodiment of the present application will be described. In the following illustrated mode, the same symbols as those used in the description of the first embodiment are used for elements that function similarly to those of the first embodiment, and the respective detailed descriptions are appropriately omitted.

[0136] Figure 8 A perspective view showing an outline of the three-dimensional object printing apparatus 100 and the workpiece W according to the second embodiment. The structure of the three-dimensional object printing apparatus 100 according to the present embodiment is the same as that of the first embodiment. The workpiece W according to the present embodiment has a protruding portion WP protruding in the Zl direction, and a face WF serving as a printing region is disposed so as to abut the Y2 direction side of the protruding portion WP. The protruding portion WP extends along the X axis. The size, shape, or disposition posture of the workpiece W is not limited to those shown in the example, and can be set in an arbitrary manner. Figure 8

[0137] Figure 9 A plan view for explaining the setting of the path and the printing operation in the second embodiment. The head unit 300 in the path RU according to the present embodiment is set in a posture in which the b 1 direction of the tool coordinate system is opposed to the protruding portion WP while the ejection face Fl is opposed to the face WF at the Zl direction side of the workpiece W. Further, the moving direction in the path RU is the Xl direction of the base coordinate system, and the al direction of the tool coordinate system is parallel to the Xl direction. The printing operation is implemented by moving on the path RU by the operation of the robot 200, and by causing the head 310 to eject ink toward the face WF of the workpiece W while the head unit 300 moves along the path RU.

[0138] When the head unit 300 is viewed in the c2 direction, the end portion of the b 1 direction side of the ejection face F2 does not protrude in the b 1 direction as compared to the end portion of the b 1 direction side of the ejection face Fl. In the present embodiment, the end portion of the b 1 direction side of the ejection face Fl and the end portion of the b 1 direction side of the ejection face F2 are disposed at the same position in the b 1 direction. According to this structure of the head unit 300, it is possible to prevent the ejection face F2 from interfering with the protruding portion WP when printing is performed on the region of the face WF that abuts the protruding portion WP. In addition, the end portion of the b 1 direction side of the ejection face Fl can also be disposed at the b 1 direction side as compared to the end portion of the b 1 direction side of the ejection face F2.

[0139] Further, it can also be configured such that, when the head unit 300 is viewed in the c2 direction, the end portion of the b 2 direction side of the ejection face F2 protrudes in the b 2 direction as compared to the end portion of the b 2 direction side of the ejection face Fl. This is because the end portion of the b 2 direction side is not opposed to the protruding portion WP, and thus does not interfere. However, when there is another protruding portion or the like of the workpiece W disposed at the b 2 direction side, the end portion of the b 2 direction side of the ejection face F2 can also be disposed so as to not protrude in the b 2 direction as compared to the end portion of the b 2 direction side of the ejection face Fl.

[0140] ​Further, in the present embodiment, when the head unit 300 is observed along the c2 direction, the end portion in the b-axis direction of the measurement surface F3 does not protrude outward compared to the end portion in the b-axis direction of the ejection surface Fl. Alternatively, the end portion in the b-axis direction of the measurement surface F3 and the end portion in the b-axis direction of the ejection surface Fl can also be disposed at the same position in the b-axis direction. Regardless of which approach is taken, the end portion in the b-axis direction of the measurement surface F3 need only not protrude in the bl direction or the b2 direction compared to the end portion in the b-axis direction of the ejection surface Fl, but it is further preferable that the end portion in the b-axis direction of the measurement surface F3 not protrude in both the bl direction and the b2 direction compared to the end portion in the b-axis direction of the ejection surface Fl. According to this structure of the head unit 300, it is possible to prevent the measurement surface F3 from interfering with the protrusion WP when printing is performed on the region of the surface WF that adjoins the protrusion WP. In addition, it is preferable that the direction in which the end portion does not protrude in the b-axis direction compared to the end portion of the ejection surface Fl be consistent for the ejection surface F2 and the measurement surface F3.

[0141] 3. Third Embodiment

[0142] The third embodiment of the present application will be described below. In the following illustrated mode, the same symbols as used in the description of the first embodiment are used for elements that function and function identically to the first embodiment, and the respective detailed descriptions are appropriately omitted.

[0143] Figure 10 A side view showing an outline of the head unit 300 and the workpiece W according to the third embodiment. The structure of the three-dimensional object printing apparatus 100 in the present embodiment is the same as that of the first embodiment. The workpiece W in the present embodiment has a protrusion WP that protrudes in the Zl direction, and the surface WF that is the printing region is disposed so as to adjoin the Xl direction side of the protrusion WP. The protrusion WP extends along the Y axis. The size, shape, or disposition posture of the workpiece W is not limited to that shown in the example, and can be any. Figure 10 The example shown is arbitrary.

[0144] As shown in Figure 10 the present embodiment, the head unit 300 in the path RU is disposed so as to have the a2 direction on the protrusion WP side and the al direction on the surface WF side while the ejection surface Fl opposes the surface WF on the Zl direction side of the workpiece W. Further, the direction of movement of the head unit 300 in the path RU is the Xl direction of the basic coordinate system, and the a axis of the tool coordinate system is parallel to the X axis. By moving on the path RU using the action of the robot 200, and by causing the head 310 to eject ink toward the surface WF of the workpiece W while the head unit 300 moves along the path RU, a printing action is performed.

[0145] In the three-dimensional object printing method in the present embodiment, the emission surface F2 overlaps the protruding portion WP when viewed in the ejection direction while the ejection surface F1 opposes the surface WF and ink is ejected from the head 310. Here, the ejection direction is the c2 direction. Further, as shown in FIG. 37, at least a portion of the protruding portion WP is positioned between the ejection surface F1 and the emission surface F2 in the c-axis direction. Figure 10

[0146] According to the three-dimensional object printing method described above, the need for moving the head unit 300 as a whole away from the workpiece W in order to prevent the emission surface F2 from contacting the workpiece W is reduced. In particular, even in the case where the printing region of the workpiece W is adjacent to the protruding portion WP, the ejection surface F1 can be brought close to the printing region of the workpiece W while preventing the emission surface F2 from contacting the workpiece W. Thus, the accuracy of the position at which the ink ejected from the nozzle N of the head 310 lands on the surface WF can be improved, and thus the printing quality can be improved.

[0147] Symbol explanation

[0148] 100... three-dimensional object printing apparatus; 200... robot; 210... base; 220, 221, 222, 223, 224, 225, 226... arm; 230... joint portion; 240... arm driving mechanism; 241... encoder; 300... head unit; 310... head; 311... piezoelectric element; 312... nozzle plate; 313... frame portion; 314... cover member; 320... pressure regulating valve; 330... energy emission portion; 331... window portion; 332... frame portion; 340... switching circuit; 350... support body; 360... distance measuring portion; 361... window portion; 362... frame portion; 400... liquid supply unit; 410... liquid storage portion; 420... supply flow passage; 421... upstream flow passage; 422... downstream flow passage; 500... control module; 510... timing signal generating circuit; 520... power supply circuit; 530... control circuit; 540... drive signal generating circuit; 600... controller; 610... storage circuit; 620... processing circuit; 700... computer; C... imaginary circle; F1... ejection surface; F2... emission surface; F3... measurement surface; F11... nozzle surface; F12... cover surface; F21... window surface; F22... frame surface; F31... window surface; F32... frame surface; La... first nozzle row; Lb... second nozzle row; N... nozzle; O1... first rotation axis; O2... second rotation axis; O3... third rotation axis; O4... fourth rotation axis; O5... fifth rotation axis; O6... sixth rotation axis; RU... route; W... workpiece; W310, W330, W331... width; WF... surface; WP... protruding portion.​

Claims

1. A stereolithography apparatus characterized by, Having: a head unit including a head and a hardening unit, the head having an ejection surface provided with nozzles and ejecting a liquid toward a three-dimensional workpiece from the nozzles, the hardening unit having an emission surface that emits energy capable of hardening the liquid; a moving mechanism that changes a relative position and posture of the workpiece and the head unit, when a direction in which the head ejects the liquid is set as an ejection direction, the ejection surface is located on a side closer to the ejection direction than the emission surface, a plurality of nozzles are provided on the ejection surface along a nozzle row axis, a plurality of rotation axes are included in the moving mechanism, the plurality of rotation axes including a rotation axis that is parallel to the nozzle row axis, in a state in which a rotation axis closest to the head unit among the rotation axes that are parallel to the nozzle row axis, that is, a center rotation axis, is parallel to the nozzle row axis, when the head is observed in a direction along the nozzle row axis, when a distance between an end of the ejection surface that is farthest from the center rotation axis and the center rotation axis is set as R, the emission surface is located on an inner side of an imaginary circle having the center rotation axis as a center and a radius of R.

2. The three-dimensional object printing apparatus according to claim 1, wherein in the head unit, a positional relationship of the ejection surface and the emission surface with respect to each other is fixed.

3. The three-dimensional object printing apparatus according to claim 1, wherein the head unit further includes a distance measuring unit having a measurement surface that measures a relative distance to the workpiece, the ejection surface is located on a side closer to the ejection direction than the measurement surface.

4. A stereolithography apparatus characterized by comprising: Having: a head unit including a head and a distance measuring unit, the head having an ejection surface provided with nozzles and ejecting a liquid toward a three-dimensional workpiece from the nozzles, the distance measuring unit having a measurement surface that measures a relative distance to the workpiece; a moving mechanism that changes a relative position and posture of the workpiece and the head unit, when a direction in which the head ejects the liquid is set as an ejection direction, the ejection surface is located on a side closer to the ejection direction than the measurement surface, a plurality of nozzles are provided on the ejection surface along a nozzle row axis, a plurality of rotation axes are included in the moving mechanism, the plurality of rotation axes including a rotation axis that is parallel to the nozzle row axis, in a state in which a rotation axis closest to the head unit among the rotation axes that are parallel to the nozzle row axis, that is, a center rotation axis, is parallel to the nozzle row axis, when the head is observed in a direction along the nozzle row axis, when a distance between an end of the ejection surface that is farthest from the center rotation axis and the center rotation axis is set as R, the measurement surface is located on an inner side of an imaginary circle having the center rotation axis as a center and a radius of R.

5. The three-dimensional object printing apparatus according to claim 4, wherein in the head unit, a positional relationship of the ejection surface and the measurement surface with respect to each other is fixed.

6. The three-dimensional object printing apparatus according to claim 4, wherein the head unit further includes a hardening unit having an emission surface that irradiates energy capable of hardening the liquid, the emission surface is located on a side closer to the ejection direction than the measurement surface. The ejection surface is located on the side of the ejection direction compared to the emission surface.

7. The apparatus according to claim 3 or 6, wherein In the ejection direction, the emission surface is located between the measurement surface and the ejection surface.

8. The apparatus according to claim 3 or 6, wherein In the ejection direction, the distance from the emission surface is shorter than the distance from the measurement surface.

9. The apparatus according to claim 3 or 6, wherein On the ejection surface, a plurality of nozzles are arranged along a nozzle row axis, In a direction orthogonal to both the nozzle row axis and the ejection direction, The ejection surface is located between the emission surface and the measurement surface.

10. The apparatus according to claim 3 or 6, wherein When the head unit is viewed from the side of the ejection direction, at least a portion of a flow path that supplies the liquid to the head is located between the distance measurement unit and the hardening unit, The distance measurement unit and the hardening unit generate heat by driving.

11. The apparatus according to claim 1 or 6, wherein On the ejection surface, a plurality of nozzles are arranged along a nozzle row axis, In a direction orthogonal to both the nozzle row axis and the ejection direction, the width of the ejection surface is narrower than the width of the emission surface.

12. The apparatus according to claim 1 or 6, wherein The emission surface is obliquely arranged toward the side opposite to the side toward which the head is located.

13. The apparatus according to claim 1 or 6, wherein On the ejection surface, a plurality of nozzles are arranged along a nozzle row axis, At at least one side in the direction along the nozzle row axis, the end of the emission surface does not protrude from the end of the ejection surface.

14. The apparatus according to claim 4, wherein On the ejection surface, a plurality of nozzles are arranged along a nozzle row axis, At at least one side in the direction along the nozzle row axis, the end of the measurement surface does not protrude from the end of the ejection surface.

15. The apparatus according to claim 1 or 4, wherein The movement mechanism is a multi-joint robot having a plurality of joints.

16. A three-dimensional object printing method, wherein Printing is performed on a printing region of a three-dimensional workpiece by a head unit of the three-dimensional object printing apparatus according to claim 1, In the three-dimensional object printing method, The workpiece has a protruding portion protruding toward the head unit side at a position different from the printing region, When the ejection surface is opposed to the printing region and the liquid is ejected from the head, the emission surface overlaps the protruding portion when viewed in the ejection direction.

17. The three-dimensional object printing method according to claim 16, wherein When the ejection surface is opposed to the printing region and the liquid is ejected from the head, In the ejection direction, at least a portion of the protruding portion is located between the ejection surface and the emission surface.

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