JP2016137703A - Three-dimensional molding apparatus, three-dimensional molding method and computer program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reproduce a color faithful to object data indicating the shape and the color of an object upon molding the object.SOLUTION: A model Pt0 is formed by discharging liquid droplets of the same color on the basis of the same reference signal from a droplet discharging unit Nc onto a medium (S10). The model Pt0 is subjected to colorimetry to specify a first portion R1 and a second portion R2 having a color with a higher density than that of the first portion (S20). A liquid amount of droplets per unit area discharged from a first type of the droplet discharge part Nc used to form the first portion R1, and a liquid amount of droplets per unit area discharged from a second type of the droplet discharge part Nc used to form the second portion R2 are adjusted to decrease a difference in the density of reproduced colors (S30). A process of forming a planar structure Ps by discharging droplets from the droplet discharge part Nc on the basis of object data indicating the shape and the color of an object is repeated to form a new planar structure Ps on an already formed planar structure Ps to mold the object (S40).SELECTED DRAWING: Figure 2

Description

  The present invention relates to a technique for modeling a three-dimensional object.

  Conventionally, a three-dimensional object is formed by repeating the process of discharging and curing droplets at successive positions on a flat surface to form a plate-like member and then forming a plate-like member thereon. There exists a technique to perform (Patent Document 1). In such a technique, a desired color can be imparted to a three-dimensional object by supplying C (cyan), M (magenta), and Y (yellow) droplets at an appropriate ratio. it can.

JP 2009-12413 A JP 2013-67121 A

  However, due to variations in the amount of each droplet and variations in the landing position of each droplet, there may be a case where a color faithful to the object data representing the shape and color of the object cannot be reproduced when the object is formed.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

(1) According to one aspect of the present invention, there is provided a three-dimensional modeling apparatus that models an object by discharging droplets. The three-dimensional modeling apparatus includes: a plurality of droplet discharge units that can discharge droplets; a support unit that supports a structure constituted by the droplets; A scanning unit capable of relatively moving the plurality of droplet ejection units in a first direction intersecting with the ejection direction, and in a second direction intersecting with the droplet ejection direction and the first direction; A control unit that controls the droplet discharge unit, the support unit, and the scanning unit. The control unit includes: a model forming unit that forms a model by discharging droplets having a predetermined same color based on the same reference signal from the plurality of droplet discharge units; and measuring the model. A colorimetric unit that colorally identifies a first portion of the model and a second portion of the model having a color with a higher density than the first portion; and Of these, the amount of liquid droplets per unit area ejected from the first type of liquid droplet ejecting portion that formed the first portion, and the second portion that formed the second portion of the plurality of liquid droplet ejecting portions. At least one of the liquid volume per unit area discharged from the two types of droplet discharge units is the difference in color density reproduced by the first type and second type droplet discharge units. An adjustment unit that adjusts so as to reduce the shape; and the shape and color of the object from the plurality of droplet discharge units. A plate-like structure is newly formed on the already-formed plate-like structure by repeating the process of forming a plate-like structure by discharging droplets based on the object data. And a modeling part for modeling.
With such an aspect, it is possible to form an object while reproducing a color faithful to object data representing the shape and color of the object.

  The plate-like structure does not need to be constituted only by droplets. That is, the plate-like structure may be constituted by droplets and other components. In addition, the plate-like structure may be configured by a droplet that reacts with another component or is modified by itself to be changed into another substance.

(2) In the three-dimensional modeling apparatus of the above aspect, the adjustment unit is a signal supplied to the first type droplet discharge unit prior to modeling the object, and discharges one droplet. At least one of a signal and a signal supplied to the second type of droplet discharge unit for discharging one droplet is the first type and the second type of droplet discharge unit. It is possible to make an adjustment so that the difference in the discharge amount of one droplet is reduced. With such an aspect, the color faithful to the object data can be reproduced even for a minute region by adjusting the amount of each droplet ejected from each droplet ejection unit.

(3) In the three-dimensional modeling apparatus of the above aspect, the adjustment unit is a signal supplied to the second type droplet discharge unit in the process of modeling the object, and discharges one droplet It is possible to adopt a mode in which the signal is adjusted so as to eject a smaller amount of one droplet. According to such an aspect, it is possible to reduce the difference in the discharge amount of one droplet between the first type and the second type droplet discharge unit while making use of the capability of the first type droplet discharge unit. it can.

(4) In the three-dimensional modeling apparatus of the above aspect, when the adjustment unit is designated to have the same density, a discharge rate that represents a ratio at which droplets are discharged from the first type droplet discharge unit; At least one of a discharge rate representing a ratio at which droplets corresponding to the droplets discharged from the first type droplet discharge unit are discharged from the second type droplet discharge unit is defined as the first type. And a mode in which adjustment is performed so that a difference in color density reproduced by the second type droplet discharge unit is reduced. According to such an aspect, the color faithful to the object data representing the shape and color of the object is reproduced without changing the drive signals supplied to the first and second type droplet discharge units, and the object is Can be shaped.

(5) In the three-dimensional modeling apparatus of the above aspect, the modeling unit is: cross-sectional data generated from the object data, based on cross-sectional data representing the cross-sectional shape of the object and the color of the outer periphery of the cross-section The plate-like structure having the cross-sectional shape is formed by discharging droplets from the plurality of droplet discharge portions; and a plurality of cross-sections of the object that are arranged in a direction perpendicular to the cross-section. About a cross section, it can be set as the aspect which overlaps and forms the said several plate-shaped structure by repeating the process which forms the said plate-shaped structure. And the process of forming the plate-like structure includes: a process of forming a first structure portion including an outer periphery of the cross section by discharging droplets from the plurality of droplet discharge portions according to the adjustment; A second structure surrounded by the first portion of the cross section by discharging droplets having the predetermined color from a plurality of other droplet discharge portions different from the plurality of droplet discharge portions And a process of forming a portion. If it is such an aspect, about the outer periphery of an object, modeling can be performed, reproducing a color faithful to object data. On the other hand, the inside of the object can be suitably shaped according to a request different from the color accuracy.

(6) According to another aspect of the present invention, there is provided a method for modeling an object by discharging droplets. The method includes: (a) forming a model by discharging droplets having a predetermined same color from a plurality of droplet discharge units based on the same reference signal; and (b) the model Measuring a first part of the model and a second part of the model having a color with a higher density than the first part; and (c) the plurality of droplets The amount of liquid droplets per unit area ejected from the first type of liquid droplet ejection part that forms the first part of the ejection part, and the second part of the plurality of liquid droplet ejection parts. At least one of the liquid volume per unit area discharged from the formed second type droplet discharge unit is a color density reproduced by the first type and second type droplet discharge units. And (d) adjusting the shape and shape of the object from the plurality of droplet discharge portions. By repeating the process of forming a plate-like structure by discharging droplets based on the object data representing the color, a plate-like structure is newly formed on the already formed plate-like structure, Forming the object.

  In addition, a process (c) may be performed before a process (d), and may be performed, performing a process (d).

  A plurality of constituent elements of each aspect of the present invention described above are not indispensable, and some or all of the effects described in the present specification are to be solved to solve part or all of the above-described problems. In order to achieve the above, it is possible to appropriately change, delete, replace with another new component, and partially delete the limited contents of some of the plurality of components. In order to solve part or all of the above-described problems or to achieve part or all of the effects described in this specification, technical features included in one embodiment of the present invention described above. A part or all of the technical features included in the other aspects of the present invention described above may be combined to form an independent form of the present invention.

  The present invention can be realized in various forms other than the apparatus. For example, it can be realized in the form of a three-dimensional modeling method, a three-dimensional modeling apparatus control method, a computer program for realizing the control method, a non-temporary recording medium on which the computer program is recorded, or the like.

It is explanatory drawing which shows schematic structure of the three-dimensional modeling apparatus as 1st Embodiment of this invention. It is a flowchart explaining the process of modeling of the three-dimensional object in this embodiment. It is explanatory drawing for demonstrating the process in step S20 of FIG. It is explanatory drawing for demonstrating the process in step S30 of FIG. It is explanatory drawing which shows the process at the time of the control part 70 driving the head part 50 according to cross-sectional data in step S44 of FIG. 2, and discharging a hardening liquid to a powder layer. It is explanatory drawing which shows the relationship between each voxel and the hardening liquid in the cross-sectional data corresponding to the uppermost layer of a rectangular parallelepiped in the case of modeling the rectangular parallelepiped as a three-dimensional object. It is a flowchart explaining the process of modeling of the three-dimensional object in 2nd Embodiment. It is a figure which shows the gradation value of the ink color allocated to each voxel, and the discharge rate of a droplet. It is explanatory drawing which shows the method of applying the dither method when the gradation value which should be expressed is 56, and determining the presence or absence of the supply of the droplet to each voxel. It is explanatory drawing which shows schematic structure of the three-dimensional modeling apparatus in 3rd Embodiment.

A. First embodiment:
FIG. 1 is an explanatory diagram showing a schematic configuration of a three-dimensional modeling apparatus as a first embodiment of the present invention. The three-dimensional modeling apparatus 100 includes a modeling unit 10, a powder supply unit 20, a flattening mechanism 30, a powder recovery unit 40, a head unit 50, a curing energy application unit 60, a control unit 70, and a measurement unit. And a color device 80. A computer 200 is connected to the control unit 70. The three-dimensional modeling apparatus 100 and the computer 200 can be combined and understood as a “three-dimensional modeling apparatus” in a broad sense.

  FIG. 1 shows an X direction, a Y direction, and a Z direction orthogonal to each other. The Z direction is a direction along the vertical direction, and the X direction is a direction along the horizontal direction. The Y direction is a direction perpendicular to the Z direction and the X direction.

  The modeling unit 10 includes a container 10c whose upper surface is open, and is a structure for modeling a three-dimensional object inside the container 10c. The modeling unit 10 moves the modeling stage 11 having a flat upper surface along the XY direction, the frame 12 surrounding the modeling stage 11 and standing in the Z direction, and the modeling stage 11 along the Z direction. And an actuator 13. A container 10c is constituted by the modeling stage 11 constituting the bottom surface and the frame body 12 constituting the side surface. When the control unit 70 controls the operation of the actuator 13, the modeling stage 11 can move in the Z direction within the frame 12. The material constituting the three-dimensional object is supplied to the container 10c. In the first embodiment, a photocurable liquid (hereinafter referred to as “curing liquid”) and powder are used as the material of the three-dimensional object.

  The powder supply unit 20 is an apparatus that supplies powder as a material constituting a three-dimensional object into a container 10 c constituted by the modeling stage 11 and the frame body 12. The powder supply unit 20 is configured by, for example, a hopper or a dispenser.

  The flattening mechanism 30 moves the upper surface of the powder in the container 10 c in the horizontal direction (XY direction), thereby flattening the upper surface of the powder in the container 10 c and forming a powder layer on the modeling stage 11. . The flattening mechanism 30 is configured by, for example, a squeegee (a spatula) or a roller. The powder pushed out from the upper surface of the powder in the container 10c by the flattening mechanism 30 is discharged into a powder recovery unit 40 provided adjacent to the container 10c.

  The curable liquid for constituting the three-dimensional object is a mixture of a liquid resin material and a polymerization initiator. The liquid resin material is mainly composed of a monomer and an oligomer to which the monomer is bonded. As the monomer for the resin material, a monomer having a relatively low molecular weight is selected. The number of monomers contained in one oligomer of the resin material is adjusted to about several molecules. Since the monomer and oligomer are adjusted in this way, the viscosity of the curable liquid is low enough to be ejected as droplets from the head unit 50.

  The polymerization initiator becomes an excited state when irradiated with ultraviolet light, and acts on the monomer or oligomer to start polymerization. When the curing liquid is irradiated with ultraviolet light and the polymerization initiator is excited, the monomers of the resin material are polymerized to grow into oligomers, and the oligomers are also polymerized in some places. As a result, the curable liquid quickly cures to become a solid.

  A different type of polymerization initiator from that contained in the curable liquid is attached to the surface of the powder as a material constituting the three-dimensional object. The polymerization initiator attached to the surface of the powder has the property of initiating polymerization by acting on the monomer or oligomer of the curable liquid when in contact with the curable liquid. Therefore, when the curable liquid is supplied to the powder in the container 10c, the curable liquid penetrates into the interior of the powder, and the curable liquid comes into contact with the polymerization initiator on the surface of the powder to be cured. As a result, in the portion where the curable liquid is discharged, the powders are bonded by the cured curable liquid. In addition, when using the powder by which the polymerization initiator adhered to the surface, it is also possible to use the hardening liquid which does not contain a polymerization initiator.

  The head unit 50 of the present embodiment is a so-called piezo drive type droplet discharge head. The head unit 50 is supplied with the above-described curable liquid from a tank 51 connected to the head unit 50. The control unit 70 can adjust the amount of the curable liquid ejected from one nozzle provided in the head unit 50 by controlling the waveform of the voltage of the signal applied to the piezo element.

  The curable liquid supplied to the head unit 50 may be cyan, magenta, or yellow, and may not be colored. The head unit 50 includes a nozzle row of nozzles Nc that discharges droplets of a curable liquid colored cyan, a nozzle row of nozzles Nm that discharges droplets of a curable liquid colored magenta, And a nozzle row of nozzles Ny for discharging droplets of the curable liquid colored with a color and a nozzle row of nozzles Nt for discharging liquid droplets of colorless curable liquid. The numbers of nozzles Nc, Nm, Ny are equal to each other. The number of nozzles Nt is equal to the total number of nozzles Nc, Nm, and Ny.

  The nozzles of each nozzle row are arranged along the Y direction. The nozzle rows Nc, Nm, Ny, Nt are arranged side by side in the X direction. Of the three-dimensional object, a portion formed by combining powder with one or more colored curable liquids has a color corresponding to the color of the one or more curable liquids used. Hereinafter, cyan, magenta, and yellow colors applied to the curable liquid may be referred to as “ink colors”.

  The head unit 50 is movable in the X direction and the Y direction with respect to the container 10c (modeling stage 11) by the scanning unit 52. The movement of the head unit 50 by the scanning unit 52 is also referred to as “scanning”. When the modeling stage 11 in the modeling unit 10 moves in the Z direction, the head unit 50 is relatively movable in the Z direction with respect to the container 10c and the three-dimensional object in the container 10c.

  The curing energy applying unit 60 is an apparatus for applying energy for curing the curable liquid to the curable liquid discharged from the head unit 50. In the present embodiment, the curing energy applying unit 60 is the light emitting device 61. The light emitting device 61 emits ultraviolet rays as curing energy for curing the curable liquid.

  The curing energy applying unit 60 is fixed to the head unit 50 at a position aligned with the head unit 50 in the X direction. When the head unit 50 is moved by the scanning unit 52, the curing energy application unit 60 (light emitting device 61) also moves together with the head unit 50.

  The colorimeter 80 is a colorimetric sensor that can measure the color of an object placed on the modeling stage 11. In the present embodiment, the colorimeter 80 is fixed to the head unit 50 on the side opposite to the curing energy applying unit 60 across the head unit 50 in the X direction. The color measuring device 80 can also be moved in the X direction and the Y direction with respect to the modeling stage 11 by the scanning unit 52. The CPU 210 of the computer 200 can measure the color of the object at each position on the modeling stage 11 using the colorimeter 80 via the control unit 70.

  In accordance with an instruction from the CPU 210 of the computer 200, the control unit 70 includes the actuator 13, the powder supply unit 20, the flattening mechanism 30, the head unit 50, the curing energy application unit 60, and the colorimeter 80. Control. The control unit 70 can model a three-dimensional object in the container 10 c by controlling each unit of the three-dimensional modeling apparatus 100. The control unit 70 includes a CPU, a memory, and a ROM. The CPU implements a function of printing a model and a function of modeling a three-dimensional object, as will be described later, by loading a computer program stored in the ROM into the memory and executing it. Note that these functions of the control unit 70 may be provided on the computer 200 side.

  The computer 200 includes a CPU 210, a memory, and a ROM. The CPU 210 loads a computer program stored in the ROM into the memory and executes it, thereby realizing a function of generating cross-sectional data, which will be described later, and a function of setting a drive signal for the piezo element according to the color measurement result. Further, the CPU 210 controls and operates the 3D modeling apparatus 100 via the control unit 70.

  FIG. 2 is a flowchart for explaining processing of modeling a three-dimensional object in the present embodiment. In step S10, the CPU 210 of the computer 200 prints the model. More specifically, the CPU 210 controls the powder supply unit 20 and the flattening mechanism 30 via the control unit 70 of the three-dimensional modeling apparatus 100 to form one powder layer in the container 10c. To do. Then, the CPU 210 uses the model data stored in the ROM of the computer 200 to drive the piezo element of one nozzle row of the head unit 50 via the control unit 70, and to powder the curable liquid. Discharge to the body layer. As a result, a model Pt0 is formed on the modeling stage 11 using a single color curable liquid. The nozzle array used to form the model Pt0 can be a nozzle array that discharges any one of cyan, magenta, and yellow droplets. In forming the model Pt0, the same reference signal is supplied to the piezo elements corresponding to the respective nozzles.

  In forming the model in step S10, so-called pseudo band printing as described below is performed. The control unit 70 causes the head unit 50 to scan in the X direction via the scanning unit 52 and ejects droplets from each nozzle of one nozzle array arranged in the Y direction. At that time, the head unit 50 and the curing energy application unit 60 are scanned so that the head unit 50 first passes through each part on the powder layer, and then the curing energy application unit 60 passes. As a result, the curable liquid discharged from the head unit 50 to the powder layer is then cured by being irradiated with ultraviolet rays by the curing energy applying unit 60.

  Thereafter, the control unit 70 moves the head unit 50 along the X direction to a position before starting scanning in the X direction via the scanning unit 52. Then, the control unit 70 scans the head unit 50 in the Y direction via the scanning unit 52. The magnitude of scanning in the Y direction performed during scanning in the X direction is 1 / n (n is an integer of 2 or more) of the pitch of nozzles arranged along the Y direction. And the control part 70 discharges a droplet from each nozzle, making the head part 50 scan again about a X direction.

  In this way, the model Pt0 is printed on the print medium by repeating (n−1) times the scanning in the X direction and the scanning in the Y direction performed while discharging droplets. In the model Pt0 printed by such printing, a certain range in the Y direction (that is, a nozzle pitch range) is printed by droplets ejected from the same nozzle. A functional unit of the CPU 210 of the computer 200 that realizes the process of step S10 is shown as a model forming unit 212 in FIG.

In step S20 of FIG. 2, the CPU 210 uses the colorimeter 80 via the control unit 70 to measure the color at each position of the model Pt0 formed in step S10.
More specifically, using the scanning unit 52, the colorimeter 80 is scanned in the X direction and the Y direction on the model Pt0, and the colorimeter 80 measures the color at each position of the model Pt0. . Then, the CPU 210 has a reference part R0 whose density is within a reference density range including the reference density, a first part R1 whose density is lower than the reference density range, and a second part R2 whose density is higher than the reference density range. And specify. The reference density range can be, for example, a density range of plus or minus 5% (a range of 95% or more and 105% or less of the reference density). Here, “density” is a value obtained by taking the logarithm of reflected light with respect to incident light. Note that the functional unit of the CPU 210 of the computer 200 that implements the process of step S20 is shown in FIG.

  FIG. 3 is an explanatory diagram for explaining the processing in step S20 of FIG. FIG. 3 does not accurately reflect the actual dot size or color density. The left side of FIG. 3 shows an image of a model that should be reproduced by applying the same reference signal to the piezo elements of each nozzle, assuming that the piezo elements of each nozzle and each nozzle are ideal. Di0 is shown. The image Di0 is a rectangular image having a uniform density.

The right side of FIG. 3 shows the density distribution of the model Pt0 reproduced by applying the same reference signal to the piezo elements of the nozzles of the actual head unit 50. Model Pt0 is
It is a rectangular image having a portion R0 whose density is within a reference density range including a reference density, a part R1 whose density is lower than R0, and a part R2 whose density is higher than R0. Even if the model is printed using the same curable liquid based on the same reference signal, the density may vary depending on the region as shown on the right side of FIG. The cause is thought to be as follows.

  Ideally, colored droplets of the curable liquid are ejected from each nozzle along the Z direction (see FIG. 1), and the droplets are evenly arranged in the X direction on the modeling stage 11, In addition, a row of dots Dt0 arranged evenly in the Y direction is formed. However, there are cases where a droplet to be ejected in parallel with the Z direction from a certain nozzle flies in the Y axis + direction. In such a case, the dot row DL2 arranged in the X direction formed by the droplets ejected from the nozzle is formed at a position shifted in the Y axis + direction from the position where it should originally be formed. (See the center in FIG. 3). As a result, the dot row DL2 is formed at a position closer to the adjacent dot row DL1 in the Y axis + direction than the position where it should originally be formed. The dot row DL2 is formed at a position farther from the dot row DL3 in the Y-axis direction than the position where it should originally be formed. The same phenomenon occurs when a droplet to be ejected in parallel with the Z direction from a certain nozzle flies in the Y-axis negative direction (see dot row DL5 in the figure).

  Of the model Pt0 formed in step S10, the density of the portion where the dot rows arranged in the X direction are formed at positions close to each other is high. The density of the portions where the dot rows arranged in the X direction are formed at positions separated from each other is low.

  In the case where a droplet to be ejected in parallel with the Z direction from a certain nozzle flies with a deviation in the X direction, as long as the deviation angle is constant, the density is compared with the case of deviation in the Y direction. Does not affect.

  In addition, there may be a deviation in the amount of droplets ejected from each nozzle due to manufacturing errors of the piezo elements connected to each nozzle. In such a case, the size of the dot row formed by the liquid droplets ejected from each nozzle will deviate from the original size of the dot Dt0. For this reason, in the model formed in step S10, the density of the portion where the dot row arranged in the X direction is formed with dots smaller than the original dot Dt0 is low. The density of the portion where the dot row arranged in the X direction is formed with dots larger than the original dot Dt0 is high.

   In step S30 of FIG. 2, the CPU 210 of the computer 200 determines a signal to be applied to each piezo element so that the difference in the density of the printing result by each nozzle decreases according to the density measurement result in step S20. To do. More specifically, first, the CPU 210 specifies the nozzle that printed the first portion R1 from the position information of the first portion R1 (see FIG. 3) obtained in step S20. Further, the CPU 210 specifies the nozzle that printed the second portion R2 from the position information of the second portion R2 (see FIG. 3) obtained in step S20.

  Then, the CPU 210 determines that the amount of the curable liquid per droplet ejected from the nozzle is smaller than the amount of the curable liquid per droplet ejected by the reference signal in the piezoelectric element corresponding to the nozzle that printed the first portion R1. A drive signal having a drive waveform that increases the number of times is assigned. The CPU 210 determines that the amount of the curable liquid per droplet ejected from the nozzle is smaller than the amount of the curable liquid per droplet ejected by the reference signal in the piezoelectric element corresponding to the nozzle that printed the second portion R2. A drive signal having such a drive waveform is assigned.

  The drive signal assigned to the piezo element corresponding to the nozzle on which the first portion R1 is printed is reproduced when a droplet is ejected by supplying the drive waveform to an ideal piezo element that the head unit 50 should have. The driving signal is such that the density of the printing result is 105% of the reference density. On the other hand, the drive signal assigned to the piezo element corresponding to the nozzle that printed the second portion R2 is when the drive waveform is supplied to the ideal piezo element that the head unit 50 should have and the droplets are ejected. The drive signal is such that the density of the printed result to be reproduced is 95% of the reference density. The drive signal data assigned to the piezoelectric element corresponding to the nozzle that printed the first portion R1 and the drive signal data assigned to the piezoelectric element corresponding to the nozzle that printed the second portion R2 are stored in advance in the ROM of the control unit 70. Can be remembered.

  FIG. 4 is an explanatory diagram for explaining the processing in step S30 of FIG. FIG. 4 does not accurately reflect the actual dot size or color density. On the left side of FIG. 4, assuming that the piezo elements of each nozzle and each nozzle are ideal, they should be reproduced by giving the drive signal assigned in step S30 to the piezo elements of each nozzle. A virtual model image Di1 is shown. In the image Di1, in a portion corresponding to the first portion R1 of the model, a color darker than the reference density (specifically, the density is 105% of the reference density) is reproduced. In the image Di1, in a portion corresponding to the second portion R2 of the model, a lighter color than the reference density (specifically, the density is 95% of the reference density) is reproduced.

  The right side of FIG. 4 is reproduced when it is assumed that the drive signal assigned in step S30 of FIG. 2 is supplied to the piezo elements of each nozzle of the actual head unit 50 and the model is printed again. The concentration distribution of model Pt1 is shown. The model Pt1 has a density that is smaller than the model Pt0 and that is entirely included in the reference density range. This is because, in the model Pt0 formed in step S10, for the piezo element on which the low density portion R1 has been printed, a larger dot Dt1 is formed, and as a result, a drive signal for performing higher density printing. (See dot row DL5 in FIGS. 3 and 4). Further, in the model Pt0, for the piezo element on which the portion R2 with high density was printed, a smaller dot Dt2 was formed, and as a result, a drive signal for performing printing with lower density was assigned (FIG. 3 and the dot row DL1 in FIG. 4).

  Even when there is a deviation in the amount of one droplet ejected from each nozzle due to a manufacturing error of a piezo element connected to each nozzle, and the printed result is shaded, the entire process is performed by the process of step S30. Can be printed with a density within the reference density range. In the model Pt0 formed in step S10, since each dot is small, a drive signal that forms a larger dot is assigned to the piezo element that has printed the portion R1 having a low density, and each dot is large. This is because a drive signal for forming a smaller dot is assigned to the piezo element on which the portion R2 having a high density is printed.

  By the process of step S30, an appropriate drive signal is assigned to the piezo element that discharges the colored liquid droplets of the curable liquid. As a result, the amount of liquid droplets per unit area ejected from the piezoelectric element forming the first portion R1, and the liquid droplets per unit area ejected from the piezoelectric element forming the second portion R2. The amount is adjusted so that the difference in density of colors reproduced by the piezo elements is reduced. A functional unit of the CPU 210 of the computer 200 that implements the process of step S30 is shown as an adjustment unit 216 in FIG.

  The processing in steps S10 to S30 in FIG. 2 is performed for each nozzle row Nc, Nm, Ny that discharges a colored curable liquid. By performing the processing of steps S10 to S30 in FIG. 2, when modeling a three-dimensional object using the three-dimensional modeling apparatus 100, a three-dimensional object is modeled while reproducing a desired color using each ink color. can do.

  In step S40 of FIG. 2, the CPU 210 of the computer 200 controls the 3D modeling apparatus 100 to model a 3D object. First, in step S42, the CPU 210 obtains a plurality of plate-like structures obtained by slicing the shape of the three-dimensional object from the three-dimensional data representing the shape of the three-dimensional object according to the Z-direction modeling resolution (for example, 600 dpi). Data along the X and Y directions is generated. This data is called “cross-sectional data”.

  The three-dimensional data representing the shape of the three-dimensional object is data representing the shape of the three-dimensional object and the color of the surface. The cross-sectional data has a predetermined modeling resolution (for example, 1200 dpi × 1200 dpi × 1200 dpi) in the X direction, the Y direction, and the Z direction. The cross-section data is data representing the shape of the three-dimensional object and the color of the outer periphery in a predetermined cross section (XY plane). The cross-sectional data has a predetermined modeling resolution (for example, 600 dpi × 600 dpi) in the X direction and the Y direction.

  In generating the cross-sectional data, the CPU 210 determines, based on the three-dimensional data, from the resolution of the three-dimensional data (for example, 1200 dpi × 1200 dpi × 1200 dpi in each of the XYZ directions) according to the performance of the three-dimensional modeling apparatus 100 ( For example, resolution conversion is performed at 600 dpi × 600 dpi × 600 dpi in each direction of XYZ. Note that a virtual element of a rectangular parallelepiped or a cube that partitions the inside of the three-dimensional space determined according to the resolution in the X direction, the Y direction, and the YZ direction is referred to as “voxel”.

  Further, the CPU 210 uses the color information (for example, represented by the basic colors of red, green, and blue) that the three-dimensional data has on the surface of the three-dimensional object to the ink color (for example, the three-dimensional modeling apparatus 100). , Cyan, magenta, yellow). In addition to the outermost voxel, the CPU 210 also gives the color information obtained in this manner to the voxel inside the outermost layer voxel.

  In step S42, the cross-sectional data stores ink color gradation values for each element determined according to a predetermined modeling resolution in the X and Y directions (for example, 600 dpi × 600 dpi in each of the XY directions). Represented by two-dimensional raster data. The gradation value stored in each element represents the amount of the curable liquid ejected to the XY coordinates corresponding to that element.

  In step S44 of FIG. 2, the CPU 210 controls the powder supply unit 20 and the flattening mechanism 30 via the control unit 70 of the three-dimensional modeling apparatus 100 to form a powder layer in the container 10c. And CPU210 drives the head part 50 via the control part 70 according to cross-sectional data, and discharges hardening liquid to a powder layer.

  More specifically, the control unit 70 scans the head unit 50 in the X direction via the scanning unit 52, and gives cyan, magenta, or yellow color from each nozzle of each nozzle row according to the cross-sectional data. The curable liquid or colorless curable liquid is discharged. At that time, the head unit 50 and the curing energy application unit 60 are scanned by the control unit 70 so that the head unit 50 first passes through each part on the powder layer, and then the curing energy application unit 60 passes. The

  Thereafter, the control unit 70 moves the head unit 50 along the X direction to a position before starting scanning in the X direction via the scanning unit 52. When the scanning in the X direction is completed, the control unit 70 causes the head unit 50 to scan in the Y direction via the scanning unit 52. And the control part 70 discharges a droplet from each nozzle, making the head part 50 scan again about a X direction. In this way, by repeating the scanning in the X direction and the scanning in the Y direction performed while discharging droplets, it corresponds to the cross-sectional data for one layer in the powder layer in the container 10c. A plate-like structure Ps is formed (see FIG. 1). The plate-like structure Ps constituted by droplets is supported by the modeling stage 11.

  In step S46, the CPU 210 determines whether or not the plate-like structure Ps has been formed according to all the cross-sectional data corresponding to the three-dimensional data representing the shape of the three-dimensional object. When the plate-like structure Ps is not formed according to all the cross-sectional data corresponding to the three-dimensional data representing the shape of the three-dimensional object (step S46: No), the process proceeds to step S48.

  In step S48, the CPU 210 drives the actuator 13 via the control unit 70 to lower the modeling stage 11 downward in the Z direction by a stacking pitch corresponding to the modeling resolution in the Z direction (for example, 600 dpi) ( (See FIG. 1). Thereafter, the process returns to step S44, and the same process is repeated. That is, the control unit 70 forms a new powder layer on the plate-like structure Ps already formed on the modeling stage 11 (see FIG. 1).

  On the other hand, when the plate-like structure Ps is formed according to all the cross-sectional data corresponding to the three-dimensional data representing the shape of the three-dimensional object in step S46 of FIG. 2 (step S46: Yes), the CPU 210 performs processing. Exit. In addition, the function part of CPU210 of the computer 200 which implement | achieves the process of step S44-S48 is shown in FIG. The modeling unit 218 implements the processes of steps S44 to S48 together with the control unit 70 of the three-dimensional modeling apparatus 100.

  FIG. 5 is an explanatory diagram showing processing when the control unit 70 drives the head unit 50 according to the cross-sectional data and discharges the curable liquid onto the powder layer in step S44 of FIG. FIG. 5 is a diagram showing a state in plan view of the plate-like structure Ps formed according to the cross-sectional data. In step S44 of FIG. 2, the CPU 210 uses the color information on the outer periphery of the cross-sectional data for the voxel VL1 that forms the outermost two-layer structural portion P1 of the plate-like structure Ps represented by the cross-sectional data. Accordingly, one or more curable liquids of cyan, magenta, and yellow are discharged from the nozzles Nc, Nm, and Ny to form the plate-like structure Ps. For the voxel VL2 constituting the inner structure portion P2 surrounded by the outermost two layers of the structure portion P1 in the plate-like structure Ps represented by the cross-sectional data, the CPU 210 supplies a transparent hardening liquid from the nozzle Nt. By discharging, a plate-like structure Ps is formed.

  Of the plate-like structure Ps represented by the cross-sectional data, when discharging the curable liquid to the outermost two layers of voxels VL1, the control unit 70 causes each piezo to discharge the colored curable liquid. The drive signal assigned in step S30 is supplied to the element.

  On the other hand, when the CPU 210 discharges the curable liquid to the other voxel VL2 surrounded by the two outermost voxels VL1 in the plate-like structure Ps represented by the cross-sectional data, the colorless curable liquid A drive signal that is not adjusted in steps S10 to S30 is supplied to each piezo element that discharges. For each piezo element that discharges a colorless curable liquid, adjustment is performed separately from the adjustment in steps S10 to S30 so that the height in the Z direction at each position of the plate-like structure Ps approaches uniformly. It may be done.

  FIG. 6 is an explanatory diagram showing the relationship between each voxel and the curable liquid in the cross-sectional data corresponding to the uppermost layer of the rectangular parallelepiped when modeling a rectangular parallelepiped as a three-dimensional object. In step S44 of FIG. 2, as described above, the CPU 210 determines the outermost two-layer voxel VL1 of the plate-like structure Ps represented by the cross-sectional data according to the color information of the outer periphery of the cross-sectional data. , Cyan, magenta and yellow curable liquids are discharged to form a plate-like structure Ps. For this reason, the CPU 210 applies cyan to the cross-section data corresponding to the uppermost layer of the rectangular parallelepiped and the voxel VL1 of the cross-section data corresponding to the layer below it according to the color information of the outer periphery of the cross-section data. , Magenta and yellow curable liquids are ejected to form a plate-like structure Ps. At that time, the control unit 70 supplies the drive signal assigned in step S30 to each piezo element that discharges the colored curable liquid. The same applies to the case where the curable liquid is discharged to each voxel of the cross-sectional data corresponding to the lowermost layer of the rectangular parallelepiped as the three-dimensional object and the cross-sectional data corresponding to the layer above it.

  According to the present embodiment described above, liquid droplets having respective ink colors can be obtained even when there are variations in the amount of droplets and variations in the landing positions of the droplets in the droplet ejection unit that ejects droplets. By using the droplets, it is possible to form a three-dimensional object having a surface with a color as originally assumed with little unevenness in density.

  The three-dimensional modeling apparatus 100 and the computer 200 in the present embodiment correspond to the “three-dimensional modeling apparatus” in [Means for Solving the Problems]. The nozzles Nc, Nm, and Ny and the piezo elements corresponding to the nozzles correspond to the “droplet discharge unit”. The modeling stage 11 corresponds to a “support portion”. The X direction corresponds to the “first direction”. The Y direction corresponds to the “second direction”. The CPU 210 of the computer 200 and the control unit 70 of the 3D modeling apparatus 100 correspond to a “control unit”.

B. Second embodiment:
FIG. 7 is a flowchart for explaining processing of modeling a three-dimensional object in the second embodiment. In the second embodiment, the head unit 50 can eject large, medium, and small droplets having different amounts from each nozzle. As a result, in the process of step S45 of FIG. 7 instead of the process of step S44 of FIG. 2, droplets of three stages having different amounts are ejected into the voxels.

  In the second embodiment, the process of step S30 in FIG. 2 of the first embodiment is not performed. Then, a process of step S43 is performed instead of the process of step S42 of FIG. In step S43, in the process corresponding to the generation of the cross-sectional data in step S42 of FIG. 2, the droplet discharge rate assigned to the gradation value of the density of each color is changed for each nozzle, thereby Adjustments are made to reduce the density difference. Other points of the second embodiment are the same as those of the first embodiment.

  FIG. 8 is a diagram showing the ink color gradation value and the droplet discharge rate assigned to each voxel in the process of step S45 of FIG. The horizontal axis GV0 is the gradation value of the ink color to be expressed in a certain voxel, and the vertical axis is the ejection rate (shown on the left) of either large or medium droplets and the corresponding level data value (shown on the right). It is. Here, the “ejection rate” is a command value representing a ratio (probability) at which droplets should be ejected from the piezo element and the nozzle as the droplet ejection unit.

  In FIG. 8, the discharge rates of small droplets, medium droplets, and large droplets with respect to the gradation value of the ink color to be expressed are represented by a one-dot chain line Ds, a two-dot chain line Dm, and a solid line Dl, respectively. For example, when expressing a region having a gradation value of 56, only small droplets are supplied to 87.5% of the voxels in that region. When a region having a gradation value of 128 is expressed, only medium droplets are supplied to 100% of the voxels of the region. When the gradation value is 96, small droplets are supplied to 50% of the voxels in the region, and medium droplets are supplied to 50% of the voxels.

  FIG. 9 is an explanatory diagram showing a method for determining whether or not to supply a droplet to each voxel by applying the dither method when the gradation value to be expressed is 56. FIG. Here, the processing content will be described assuming cross-sectional data (see FIG. 6) corresponding to the top surface of the rectangular parallelepiped. In the dither method, first, a target voxel group to be subjected to data conversion is selected from voxels of cross-sectional data. Here, it is assumed that 16 voxels of 4 rows × 4 columns in the cross-sectional data corresponding to the uppermost surface of the rectangular parallelepiped are sequentially selected. Then, data conversion using the dither matrix DM is sequentially performed on the selected target voxel group.

  For example, when expressing a region having a gradation value of 56 as shown at the left end in FIG. 9, only small droplets are supplied to 87.5% of the voxels of the region as described above (see FIG. 8). . In FIG. 9, the discharge rate of small droplets is shown in the second panel from the left. In the newly created level data Lds for small droplets, the gradation value of the small droplets is 223, which is 87.5% of the maximum value 255. Level data Lds for small droplets is shown in the center of FIG.

  Then, a dither matrix is applied to the generated level data Lds for small droplets. The dither matrix DM has a threshold value for each element for determining whether or not to supply droplets. If the gradation value of the corresponding voxel is equal to or greater than the threshold value of the dither matrix DM, a droplet is supplied to that voxel. If the gradation value of the corresponding voxel is less than the threshold value, no droplet is supplied to that voxel. In the present embodiment, the gradation value of each color has a value from 0 to 255, and the dither matrix DM is a 4 × 4 matrix corresponding to the target voxel group. Therefore, each threshold value included in the dither matrix DM is a value that equally divides the range of gradation values 0 to 255 into 16 from 15 to 255. When the gradation value of each element of the level data Lds for small droplets is compared with the threshold value of the corresponding dither matrix DM and the presence / absence of supply of droplets in each voxel is determined, the droplets The supply state is as shown at the right end of FIG.

  Similar processing is performed for medium droplets and large droplets. Note that when expressing a region having a gradation value of 56, only small droplets are supplied as described above (see FIG. 8). For this reason, the discharge rate of each of the medium droplet and the large droplet is 0, and the gradation values of the elements of the medium droplet level data Ldm and the large droplet level data Ldl are all 0. As a result, the medium droplet and the large droplet are not supplied to any voxel in the region having the gradation value of 56.

  The color of the cross-sectional data represented by the C, M, and Y gradation values (0 to 255) for each voxel is thus determined by whether or not the large, medium, and small droplets of C, M, and Y are supplied. It is converted into the represented data and used to generate the plate-like structure Ps (see step S45 in FIG. 7). In the second embodiment, in step S40, the plate-like structure Ps is formed by performing pseudo band printing. In the above, the processing content has been described assuming the cross-sectional data corresponding to the uppermost surface of the rectangular parallelepiped, but the same processing is performed on the voxels for two layers in the outer peripheral portion with respect to the other cross-sectional data (see FIG. 5). ).

  In the second embodiment, prior to the process of converting the ink color gradation value shown in FIG. 8 into the droplet discharge rate, the CPU 210 performs the following steps in step S43 of FIG. Adjust the key value.

  In the plate-like structure Ps formed by performing the pseudo band printing, the gradation corresponding to the first portion R1 (see FIG. 3) in which the density in step S20 is lower than the reference density range is the ink color gradation. The value is converted in advance by a coefficient larger than 1 (for example, 1.05). The gradation value before this conversion processing is represented by GV1 in FIG.

  In the plate-like structure Ps, the region corresponding to the first portion R1 and the region corresponding to the second portion R2 can be specified as follows. That is, the nozzle for printing each region of the plate-like structure Ps in the modeling of the plate-like structure Ps (step S45 in FIG. 7) is specified in advance. Then, it is determined whether or not each of these nozzles corresponds to the nozzle that printed the first portion R1 in step S10. Further, it is determined whether or not each of the nozzles corresponds to the nozzle that printed the second portion R2 in step S10. In this way, in step S43 of FIG. 7, the region corresponding to the first portion R1 and the region corresponding to the second portion R2 in the plate-like structure Ps can be specified in advance.

  If the gradation value GV1 before conversion is 243, for example, as a result of the above-described gradation value conversion processing, the large, medium, and small droplets corresponding to the case where the gradation value GV0 is 255 in step S45. The droplets are discharged at a frequency of That is, a large droplet is recorded in a 100% voxel with a gradation value of 243. As a result, when the plate-like structure Ps is formed according to the gradation value before conversion, the droplet discharge rate is adjusted for the portion where the density is lower than the reference density range (see R1 in FIG. 3). And higher concentrations are reproduced.

  Similarly, in the plate-like structure Ps formed by performing the pseudo band printing, the region corresponding to the second portion R2 (see FIG. 3) whose density in step S20 is higher than the reference density range is ink color. Are previously multiplied by a coefficient less than 1 (for example, 0.95). The gradation value before conversion is represented by GV2 in FIG. If the gradation value GV2 before conversion is, for example, 255 as a result of the above conversion processing, the liquid has a frequency of large, medium, and small droplets corresponding to the case where the gradation value GV0 is 242 in step S45. Droplet ejection is performed. As a result, when the plate-like structure Ps is formed in accordance with the gradation value before conversion, the droplet discharge rate is the portion where the density is higher than the reference density range (see R2 in FIG. 3). Adjusted to reproduce lower density.

  In step S43 of FIG. 7, when the same density is specified as a result of the above processing, the ratio of droplets (for example, small droplets) ejected from the piezo element forming the first portion R1 And a discharge rate that represents a rate at which a droplet corresponding to the droplet (for example, a small droplet corresponding to the small droplet) is discharged from the piezo element that has formed the second portion R2. The adjustment is made so that the difference in color density reproduced by each piezoelectric element is reduced. The adjustment unit 216 as a functional unit of the CPU 210 performs the processing described above.

  Thereafter, in step S45 in FIG. 7, a plate-like structure Ps is formed by ejecting large, medium, and small droplets according to the cross-sectional data generated in step S43 for each ink color (see FIG. 1).

  Even in the second embodiment described above, even when there are variations in the amount of droplets and variations in the landing positions of the droplets in the droplet ejection unit that ejects the droplets, the liquid having each ink color Drops can be used to shape a three-dimensional object having a color on the surface as originally expected.

C. Third embodiment:
FIG. 10 is an explanatory diagram illustrating a schematic configuration of the three-dimensional modeling apparatus according to the third embodiment. The three-dimensional modeling apparatus 100 according to the first and second embodiments models a three-dimensional object by discharging a curable liquid to the powder supplied into the modeling unit 10. On the other hand, the three-dimensional modeling apparatus 100a of the third embodiment models a three-dimensional object only with a curable liquid containing resin without using powder. In the third embodiment, data processing such as generation of cross-sectional data generated by the CPU 210 of the computer 200 and the control unit 70 of the three-dimensional modeling apparatus 100a, and generation of ON / OFF data of droplets generated from the cross-sectional data. Is the same process as that of the first embodiment.

  The three-dimensional modeling apparatus 100a includes a modeling unit 10, a head unit 50, a curing energy applying unit 60, a control unit 70, and a colorimeter 80. The modeling unit 10 includes a modeling stage 11, a frame body 12, and an actuator 13 as in the first embodiment. However, the frame 12 may be omitted. A tank 51 is connected to the head unit 50. The curing energy applying unit 60 is a light emitting device 61 fixed to the head unit 50 so as to be aligned with the head unit 50 in the X direction.

  The three-dimensional modeling apparatus 100a has a configuration in which the powder supply unit 20, the flattening mechanism 30, and the powder recovery unit 40 are omitted from the three-dimensional modeling apparatus 100 of the first embodiment. Other points of the 3D modeling apparatus 100a are the same as the 3D modeling apparatus 100 of the first embodiment. Even in such a three-dimensional modeling apparatus 100a, a three-dimensional object can be modeled by the same process as the three-dimensional modeling apparatus 100 of the first embodiment, except for the process of forming a powder layer.

  In the third embodiment, it is possible to form a three-dimensional object using a support material. The support material in the present embodiment is a liquid that cures with a curing energy equivalent to the curing energy for curing the curing liquid. After curing, it can be dissolved by exposure to water or a predetermined solution and easily removed. Material. If the support material is discharged toward the outside of the outline of the three-dimensional object, when forming an object with a shape having a larger cross-sectional area in the upper layer than the lower layer, the large area is Can support.

  In the three-dimensional modeling apparatus 100 of the third embodiment, the head unit 50 is provided with nozzles for discharging the curable liquid and the support material, and the head unit 50 includes a tank containing the curable liquid. The tank containing the support material is connected. In the present embodiment, the head unit 50 ejects the support material in the same scan as the scan for ejecting the curable liquid. The head unit 50 can also eject the support material in a scan different from the scan for ejecting the curable liquid.

  Also in such an aspect, printing with less shading unevenness can be performed by the processing of steps S10 to S30 in FIG. 2 of the first embodiment.

D. Variations:
D1. Modification 1:
In the above-described embodiment, the nozzles that discharge one color of the curable liquid are one row of nozzles arranged along the Y direction. However, the nozzles that discharge one color of the curable liquid may be two or more nozzles. Moreover, the nozzle which discharges the curable liquid of one color can also be set as the aspect arrange | positioned zigzag (zigzag) along the Y direction. That is, the nozzle that discharges one color of the curable liquid may include a plurality of nozzles arranged at different positions in a direction different from the direction of the operation performed while discharging the droplets.

D2. Modification 2:
In the above embodiment, the modeling stage 11 does not move in the X direction and the Y direction, and the head unit 50 including a nozzle and a piezoelectric element as a droplet discharge unit is moved by the scanning unit 52. Further, in the Z direction, the head unit 50 does not move, and the modeling stage 11 as a support unit moves by the actuator 13. However, it is also possible to adopt a mode in which the droplet discharge section moves in three directions that intersect each other. And it can also be set as the aspect which a support part moves about three directions which mutually cross | intersect. Further, it is possible to adopt a mode in which the support portion moves in two directions intersecting each other and the droplet discharge portion moves in one direction intersecting these two directions.

  In the above-described embodiment, the head unit 50 including a nozzle and a piezoelectric element as a droplet discharge unit and the modeling stage 11 as a support unit are moved in X, Y, and Z directions orthogonal to each other. However, the direction in which the droplet discharge unit and the support unit relatively move does not have to be orthogonal. However, it is preferable that the directions intersect each other.

D3. Modification 3:
In the above embodiment, the colorimeter 80 is fixed to the head unit 50 including a nozzle as a droplet discharge unit and a piezo element, and is moved by the scanning unit 52 together with the head unit 50. However, the colorimeter may be provided separately from the droplet discharge unit. However, it is preferable to be configured to be able to move in the same one or more directions as the one or more movement directions of the droplet discharge unit with respect to the support unit. The colorimeter may not be provided as a part of the three-dimensional modeling apparatus. However, the color of the model can be measured, and information on the first part of the model and the second part of the model having a color whose density is higher than that of the first part can be provided to the control unit of the three-dimensional modeling apparatus. It is preferable to be configured as described above.

D4. Modification 4:
In the above embodiment, the light emitting device 61 as the curing energy applying unit 60 is provided on one side in the X direction with respect to the head unit 50. However, the light emitting device 61 as the curing energy applying unit 60 can be provided on both sides in the X direction with respect to the head unit 50. In such an aspect, the colorimeter 80 may be provided on the opposite side of the head unit 50 with the curing energy application unit 60 interposed therebetween, and is independent of the head unit 50 and the curing energy application unit 60. May be provided.

D5. Modification 5:
In the above embodiment, the model Pt0 is formed by one layer of powder and the curable liquid. However, the model that is the object of colorimetry can also be formed in other manners. That is, the model may be formed by discharging the curable liquid onto a sheet-like member such as paper or a resin sheet disposed on the modeling stage 11. In such an embodiment, the sheet preferably has a color (for example, white) different from the color of the curable liquid.

D6. Modification 6:
In the above embodiment, the model is formed by pseudo band printing in step S10 of FIGS. However, the model may be formed by other printing methods. However, the model is preferably generated by the same scanning method as the printing method used in generating the plate-like structure performed according to the cross-sectional data.

D7. Modification 7:
In the above embodiment, the liquid volume of the ejected droplets is adjusted for a piezo element having a print result density of greater than 105% of the reference density and a piezo element having a print result density of less than 95% of the reference density. . However, the droplet discharge unit that is the target of adjusting the liquid amount of the discharged droplets can be selected along other criteria. For example, a droplet discharge unit in which the density of the printing result is greater than 103% of the reference density can be adjusted. It is also possible to adjust a droplet discharge portion whose density of the printing result is smaller than 97% of the reference density. That is, at least one of a droplet discharge unit having a high print result density and a droplet discharge unit having a low print result density among a plurality of droplet discharge units having different print result densities is used. be able to.

D8. Modification 8:
In the first embodiment, different drive signals are assigned to the piezo elements that form darker or lighter color areas than the reference density based on drive signal data stored in the ROM of the control unit 70. ing. However, a signal for discharging one droplet to be supplied to the first type droplet discharge unit and one droplet to be supplied to the second type droplet discharge unit for performing darker printing are discharged. When adjusting the signal for the purpose, other methods may be employed. For example, when generating a drive signal to be supplied to the first type and second type droplet discharge units, by changing the drive voltage to be applied while using the common drive waveform data, It is also possible to generate different drive signals by making the fluctuation range larger or smaller than the other.

D9. Modification 9:
In the above embodiment, the amount of liquid droplets per unit area ejected from the liquid droplet ejection part that forms the first portion R1, and the unit that is ejected from the liquid droplet ejection part that forms the second portion R2. Both the amount of liquid droplets per area are adjusted. However, the amount of liquid droplets per unit area ejected from the liquid droplet ejection part that forms the first portion R1 is adjusted, and the amount per unit area ejected from the liquid droplet ejection part that forms the second portion R2 is adjusted. It is also possible to adopt a mode in which the liquid amount of the liquid droplets is not adjusted. Further, the unit area discharged from the droplet discharge portion forming the second portion R2 without adjusting the liquid volume per unit area discharged from the droplet discharge portion forming the first portion R1. It is also possible to adopt a mode in which the amount of liquid droplets per hit is adjusted.

D10. Modification 10:
In the first embodiment, step S30, which is a step of adjusting so as to reduce the color density difference of the printing result, is performed before step S40, which is a step of modeling an object. However, the step of adjusting the density difference of the color of the printing result to be reduced may be performed between the processes of modeling the object. For example, it is possible to adopt a mode in which a series of processes of adjusting the cross-sectional data so as to reduce the color density difference of the printing result and then modeling the object are repeatedly performed.

D11. Modification 11:
In the above-described embodiment, a colored liquid droplet of the curable liquid is supplied to the outermost surface of the three-dimensional object to be modeled and one voxel on the innermost surface. And the droplet of the hardening liquid which is not colored is supplied to the voxel inside the three-dimensional object to be modeled. However, it is also possible to supply a colored liquid droplet of the curable liquid to the inside of the three-dimensional object to be shaped. The three-dimensional object formed in this way also has a color and a pattern on the cut surface when cut.

D12. Modification 12:
In the modeling of the three-dimensional object in the second embodiment, pseudo band printing is performed (see step S45 in FIG. 7). However, for example, in the first and third embodiments, pseudo band printing can be performed, and so-called interlaced printing can also be performed. In each embodiment, multipass printing can also be performed.

  In “interlace printing”, in one direction of scanning, a new droplet is supplied while supplying the droplet to the voxel line in the gap between the already supplied droplets arranged in the scanning direction. For the region, this is a printing method in which droplets are newly supplied to every other or several voxel lines arranged in the scanning direction. “Multi-pass printing” is a printing method in which a plurality of voxels in a line of voxels arranged in one scanning direction are shared by different droplet discharge units and supplied with droplets.

D13. Modification 13:
In the second embodiment, three types of large, medium, and small droplets can be ejected from the piezo element and the nozzle as the droplet ejection unit. However, the number of types of droplets that can be ejected from the droplet ejection unit may be one, or four or five. In addition, the three-dimensional modeling apparatus can also include droplet discharge units having different types and sizes of droplets that can be discharged.

D14. Other:
The present invention is not limited to the above-described embodiments, examples, and modifications, and can be realized with various configurations without departing from the spirit thereof. For example, the technical features in the embodiments, examples, and modifications corresponding to the technical features in each embodiment described in the summary section of the invention are to solve some or all of the above-described problems, or In order to achieve part or all of the above effects, replacement or combination can be performed as appropriate. Further, if the technical feature is not described as essential in the present specification, it can be deleted as appropriate.

DESCRIPTION OF SYMBOLS 10 ... Modeling part 10c ... Container 11 ... Modeling stage 12 ... Frame 13 ... Actuator 20 ... Powder supply part 30 ... Flattening mechanism 40 ... Powder collection part 50 ... Head part 51 ... Tank 52 ... Scanning part 60 ... Curing energy Giving unit 61 ... Light emitting device 70 ... Control unit 80 ... Colorimeter 100 ... Three-dimensional modeling device 100a ... Three-dimensional modeling device 200 ... Computer 210 ... CPU
212 ... Model forming unit 214 ... Color measuring unit 216 ... Adjusting unit 218 ... Modeling unit DL1 to DL5 ... Dot row DM ... Dither matrix Di0 ... Image reproduced by applying the same reference signal to the piezo element Di1 ... Adjusted drive Image to be reproduced by giving a signal Dl ... Recording rate of large droplets Dm ... Recording rate of medium droplets Ds ... Recording rate of small droplets GV0 ... Tone value GV1 ... Tone value before conversion GV2 ... Conversion Previous gradation value Ldl ... Level data Ldm ... Level data Lds ... Level data Nc ... Nozzle ejecting cyan droplets Nm ... Nozzle ejecting magenta droplets Nt ... Nozzle ejecting colorless droplets Ny ... Yellow Nozzle P1... The outermost two-layer structure portion P2. The inner structure portion Pt0... Model formed in step S10 Pt1. Later virtual model R0 ... reference part R1 ... first part R2 ... second part Ps ... plate-like structure VL1 ... voxel of structure part P1 of two outermost layers VL2 ... inside of structure part P2 Voxel

Claims (11)

A three-dimensional modeling apparatus that models an object by discharging droplets,
A plurality of droplet discharge portions each capable of discharging droplets;
A support for supporting the structure constituted by the droplets;
Relative to the support portion, the plurality of droplet discharge portions in a first direction intersecting with the droplet discharge direction, and in a second direction intersecting with the droplet discharge direction and the first direction. A scanning unit that can be moved automatically,
A control unit for controlling the droplet discharge unit, the support unit, and the scanning unit,
The controller is
A model forming unit that forms a model by discharging droplets having a predetermined same color based on the same reference signal from the plurality of droplet discharge units;
A colorimetric unit that performs colorimetry on the model and identifies a first part of the model and a second part of the model having a color with a higher density than the first part;
The amount of liquid droplets per unit area ejected from the first type of liquid droplet ejecting section that has formed the first portion of the plurality of liquid droplet ejecting sections, and of the plurality of liquid droplet ejecting sections, At least one of the amount of liquid droplets per unit area discharged from the second type droplet discharge unit forming the second part is reproduced by the first type and second type droplet discharge units. An adjustment unit to adjust so that the difference in density of the colors to be reduced is reduced,
A plate-like structure already formed by repeating the process of discharging a droplet from the plurality of droplet discharge units based on object data representing the shape and color of the object and forming a plate-like structure. A three-dimensional modeling apparatus comprising: a modeling unit that newly forms a plate-like structure on the model and models the object. The three-dimensional modeling apparatus according to claim 1,
The adjustment unit is a signal to be supplied to the first type droplet discharge unit, which is a signal for discharging one droplet, and the second type droplet discharge unit, prior to the modeling of the object. At least one of the signals for discharging one droplet and the difference in the discharge amount of one droplet of the first-type and second-type droplet discharge portions. A three-dimensional modeling device that adjusts so that there are fewer. The three-dimensional modeling apparatus according to claim 2,
The adjustment unit supplies a signal for supplying one droplet to the second type droplet discharge unit in the process of shaping the object, and a signal for discharging one droplet with a smaller amount. A three-dimensional modeling device that adjusts so as to discharge. The three-dimensional modeling apparatus according to claim 1,
When the same density is specified, the adjustment unit discharges from the first type droplet discharge unit, and a discharge rate that represents a ratio of droplets discharged from the first type droplet discharge unit. At least one of the discharge rate representing the rate at which the droplets corresponding to the droplets are discharged from the second type droplet discharge unit is reproduced by the first type and second type droplet discharge units. A three-dimensional modeling apparatus that adjusts so that the difference in the density of the colors to be reduced. The three-dimensional modeling apparatus according to any one of claims 1 to 4,
The modeling part is
Cross section data generated from the object data, and by discharging droplets from the plurality of droplet discharge units based on the cross section data representing the shape of the cross section of the object and the color of the outer periphery of the cross section, Forming the plate-like structure having the cross-sectional shape;
By repeating the process of forming the plate-like structure for a plurality of cross-sections of the object that are arranged in a direction perpendicular to the cross-section, a plurality of the plate-like structures are formed,
The process of forming the plate-like structure is as follows:
A process of forming a first structure portion including an outer periphery of the cross section by discharging droplets from the plurality of droplet discharge portions according to the adjustment;
A second liquid droplet surrounded by the first portion of the cross section is ejected from a plurality of droplet ejection sections different from the plurality of droplet ejection sections. A three-dimensional modeling apparatus comprising: a process for forming a structural portion. A method of modeling an object by discharging droplets,
(A) forming a model by discharging droplets having a predetermined same color from a plurality of droplet discharge units based on the same reference signal;
(B) measuring the model to identify a first portion of the model and a second portion of the model having a color with a higher density than the first portion;
(C) The amount of liquid droplets per unit area ejected from the first type of liquid droplet ejection section that forms the first portion of the plurality of liquid droplet ejection sections, and the plurality of liquid droplet ejection sections At least one of the amount of liquid droplets per unit area ejected from the second type liquid droplet ejecting portion forming the second part is the first type and second type liquid droplet ejection. A step of adjusting so as to reduce the difference in color density reproduced by the part,
(D) A plate already formed by repeating a process of discharging droplets from the plurality of droplet discharge units based on object data representing the shape and color of an object to form a plate-like structure. Forming a plate-like structure on the structure and forming the object. The method of claim 6, comprising:
The step (c)
(C1) Prior to the step (d), a signal to be supplied to the first type droplet discharge unit, which is a signal for discharging one droplet, and to the second type droplet discharge unit At least one of the supplied signal and the signal for discharging one droplet is small in the difference in the discharge amount of one droplet of the first type and the second type droplet discharge unit. The modeling method including the process of adjusting so that it may become. The method of claim 7, comprising:
In the step (c1), a signal to be supplied to the second type droplet discharge unit in the process of modeling the object, and a signal for discharging one droplet, A modeling method including the process of adjusting so that a droplet may be discharged. The method of claim 6, comprising:
The step (c)
When the same density is designated, the discharge rate representing the ratio of droplets discharged from the first type droplet discharge unit and the droplets discharged from the first type droplet discharge unit At least one of the discharge rate representing the rate at which the corresponding droplets are discharged from the second type droplet discharge unit is a color density reproduced by the first type and second type droplet discharge units. A modeling method including the process of adjusting so that a difference may become small. A method according to any one of claims 6 to 9, comprising
The step (d)
(D1) The liquid droplets are ejected from the plurality of liquid droplet ejection sections based on the cross-sectional data generated from the object data and representing the cross-sectional shape of the object and the color of the outer periphery of the cross-section. A step of forming the plate-like structure having the shape of the cross section;
(D2) forming a plurality of the plate-like structures in a stacked manner by repeating the step (d1) for different cross-sections of the object that are arranged in a direction perpendicular to the cross-section. Prepared,
The step (d1)
Forming a first structure portion including an outer periphery of the cross section by discharging droplets from the plurality of droplet discharge portions according to the adjustment in the step (c);
A second liquid droplet surrounded by the first portion of the cross section is ejected from a plurality of droplet ejection sections different from the plurality of droplet ejection sections. Forming a structural portion. A computer program for modeling an object by controlling a 3D modeling apparatus using a computer and discharging droplets,
A function of forming a model by discharging droplets having a predetermined same color from a plurality of droplet discharge units based on the same reference signal;
A function of measuring the model color to identify a first part of the model and a second part of the model having a color with a higher density than the first part;
The amount of liquid droplets per unit area ejected from the first type of liquid droplet ejecting section that has formed the first portion of the plurality of liquid droplet ejecting sections, and of the plurality of liquid droplet ejecting sections, At least one of the amount of liquid droplets per unit area discharged from the second type droplet discharge unit forming the second part is reproduced by the first type and second type droplet discharge units. A function to adjust so that the difference in the density of the colors to be reduced is reduced,
A plate-like structure already formed by repeating the process of discharging a droplet from the plurality of droplet discharge units based on object data representing the shape and color of the object and forming a plate-like structure. A computer program for causing a computer to realize a function of forming a new plate-like structure on the object and shaping the object.

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