JP2021109394A - Molding apparatus and molding method - Google Patents

Abstract

To provide a molding apparatus capable of saving a used amount of a clear ink at the time of formation of each layer and suppressing deterioration of quality of a molded object surface at the time of flattening.SOLUTION: A molding apparatus for molding a molding object by forming and laminating each layer on the basis of a plurality of slice images that show the cross-sectional shape and color arrangement of each layer of the molding object, comprises: color ink discharge position determination means that determines whether or not each of a plurality of color inks for coloring is discharged to each discharge position comprising the layer on the basis of a slice image corresponding to the layer; clear ink discharge position determination means that determines whether or not a clear ink is required to be discharged to each discharge position on the basis of whether or not each color ink for coloring is discharged to each discharge position determined by the color ink discharge position determination means; and layer formation means that causes heads for color inks and a head for a clear ink to discharge each color ink and the clear ink to each discharge position according to determinations by the color ink discharge position determination means and the clear ink discharge position determination means.SELECTED DRAWING: Figure 1

Description

The present invention relates to a modeling apparatus and a modeling method.

Conventionally, a modeling device (3D printer) for modeling a modeled object using an inkjet head is known (see, for example, Patent Document 1). In such a modeling device, for example, a modeled object is modeled by a layered manufacturing method in which a plurality of layers of ink formed by an inkjet head are stacked.

Japanese Unexamined Patent Publication No. 2015-071282

When modeling a modeled object by the additive manufacturing method, it is necessary to make the layered thickness of one layer as uniform as possible so that modeling defects do not occur.

As a method of making the laminated thickness of one layer uniform, for example, after ejecting the color ink, a large and constant amount of clear ink is ejected so as to be equal to or more than the expected laminated thickness regardless of the amount of the ejected color ink. , A method of scraping ink exceeding the expected lamination thickness with a flattening roller can be mentioned.

However, in the case of this method, the ink scraped off by the flattening roller is discarded, so that the larger the scraped amount, the more the cost is wasted. Further, the larger the amount of ink scraped off, the worse the quality of the surface of the modeled object.

Therefore, an object of the present invention is to provide a modeling apparatus and a modeling method capable of solving the above problems.

The modeling apparatus of the present invention forms and laminates each layer as an ink layer based on a plurality of slice images showing the cross-sectional shape and color arrangement of each layer of the modeled object at different positions in a predetermined stacking direction. A color that determines the presence or absence of each of the multiple color inks for coloring at each ejection position that constitutes the layer by quantization processing based on the slice image corresponding to the layer, which is a modeling device that models the modeled object. Clear ink, which is transparent ink, is ejected to each ejection position based on the presence or absence of ejection of each color ink for coloring to each ejection position determined by the ink ejection position determining means and the color ink ejection position determining means. Clear ink ejection position determining means for determining the necessity, a color ink head capable of ejecting each of a plurality of colors of ink, a clear ink head capable of ejecting clear ink, a color ink head and a clear ink head. The head is provided with a layer forming means for forming a layer by ejecting ink of each color and clear ink to each ejection position according to determination by the color ink ejection position determining means and the clear ink ejection position determining means.

The color ink ejection position determining means further determines the dot size of the ink to be ejected, and the clear ink ejection position determining means is a plurality of color inks for coloring each ejection position determined by the color ink ejection position determining means. Based on the presence or absence of ejection and the dot size, the presence or absence of clear ink ejection to each ejection position and the dot size are determined, and the color ink head and the clear ink head each eject ink of a plurality of types of dot sizes. It is possible, and the layer forming means can be applied to the color ink head and the clear ink head to each ejection position, and the ink of each color of dot size according to the determination by the color ink ejection position determining means and the clear ink ejection position determining means. Clear ink may be ejected.

As a result, at each ejection position, clear ink having a dot size corresponding to the dot size of the ejected color ink can be filled.

When the dot size is expressed by a numerical value whose value increases as the dot size increases, the clear ink ejection position determining means determines each color for coloring to be ejected to the ejection position, which is determined by the color ink ejection position determining means. The dot size of the clear ink ejected to the ejection position so that the sum of the sum of the dot size values of the ink and the dot size value of the clear ink ejected to the ejection position is as close as possible to the predetermined reference value. May be determined.

Thereby, the thickness of the formed ink layer can be made uniform.

In the modeling method of the present invention, each layer is formed as an ink layer and laminated based on a plurality of slice images showing the cross-sectional shape and color arrangement of each layer of the modeled object at different positions in a predetermined stacking direction. This is a modeling method for modeling a modeled object, and is a color that determines the presence or absence of ejection of each of the multiple color inks for coloring to each ejection position constituting the layer by quantization processing based on the slice image corresponding to the layer. Clear ink, which is transparent ink, is ejected to each ejection position based on the presence or absence of ejection of each color ink for coloring to each ejection position determined in the ink ejection position determination step and the color ink ejection position determination step. In accordance with the clear ink ejection position determination step for determining the necessity of, and the color ink ejection position determination step and the clear ink ejection position determination step for the color ink head and the clear ink head, each color ink and each color ink A layer forming step of forming a layer by ejecting clear ink is performed.

The color ink ejection position determination step further determines the dot size of the ink to be ejected.
The clear ink ejection position determination step ejects clear ink to each ejection position based on the presence or absence of ejection of each of the multiple color inks for coloring to each ejection position and the dot size determined in the color ink ejection position determination step. The color ink head and the clear ink head can each eject ink of a plurality of types of dot sizes, and the layer forming step is performed on the color ink head and the clear ink head. , Ink and clear ink of each color of dot size according to the determination in the color ink ejection position determination step and the clear ink ejection position determination step may be ejected to each ejection position.

As a result, at each ejection position, clear ink having a dot size corresponding to the dot size of the ejected color ink can be filled.

When the dot size is expressed by a numerical value whose value increases as the dot size increases, the clear ink ejection position determination step is determined in the color ink ejection position determination step for each color to be ejected to the ejection position. The dot size of the clear ink ejected to the ejection position so that the sum of the sum of the dot size values of the ink and the dot size value of the clear ink ejected to the ejection position is as close as possible to the predetermined reference value. May be determined.

Thereby, the thickness of the formed ink layer can be made uniform.

In the modeling apparatus and modeling method of the present invention, the necessity of ejecting clear ink is determined for each ejection position, and the clear ink is ejected accordingly. Therefore, the amount of clear ink used at the time of forming each layer can be saved. At the same time, the amount of ink scraped off during flattening can be reduced, so that deterioration of the quality of the surface of the modeled object can be suppressed.

It is a figure which shows an example of the structure of the modeling apparatus 100 of this invention. It is a figure which shows an example of the modeled object 50 modeled by the modeling apparatus 100. It is a figure which shows an example of the structure of the head part 110. It is a figure which shows an example of the processing flow by a control unit 140. It is a figure explaining the 1st specific example of the ejection position determination method in the clear ink ejection position determination means 143. It is a figure explaining the 2nd specific example of the ejection position determination method in the clear ink ejection position determination means 143. It is a figure explaining the 3rd specific example of the ejection position determination method in the clear ink ejection position determination means 143. It is a figure explaining the 4th specific example of the ejection position determination method in the clear ink ejection position determination means 143. It is another figure explaining the 4th specific example of the ejection position determination method in the clear ink ejection position determination means 143.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description and drawings, the same functional parts are designated by the same reference numerals, and the functional parts once described will be omitted or described to the extent necessary.

FIG. 1 shows an example of the configuration of the modeling apparatus 100 of the present invention. The modeling device 100 is a modeling device (3D printer) that models a three-dimensional modeled object 50 by a layered manufacturing method. The additive manufacturing method referred to here is data indicating the three-dimensional shape and surface color of the modeled object 50 (hereinafter referred to as "modeled object data") in a predetermined lamination direction with the thickness of the ink layer. This is a method of modeling a modeled object 50 by slicing and sequentially forming and laminating each layer as an ink layer based on the slice image of each layer obtained thereby.

FIG. 2 is a diagram showing an example of a modeled object 50 modeled by the modeling apparatus 100, and shows a configuration of an XY cross section which is a cross section of the modeled object 50 orthogonal to the stacking direction (Z direction). .. The structure of the ZX cross section and the ZY cross section of the modeled object 50 perpendicular to the Y direction and the Z direction has the same structure.

The modeled object 50 has at least an internal region 51 and a colored region 52. The modeling apparatus 100 forms the modeled object 50 by sequentially forming and laminating layers of ink having such a cross-sectional structure.

The internal area 51 is an area that constitutes the inside of the modeled object 50. Further, in the present embodiment, the internal region 51 is formed of white ink to provide a region having the function of a light reflection region. The light reflection region is a light reflective region for reflecting light incident from the outside of the modeled object 50 through the colored region 52 or the like. The light reflection region may be formed as another region formed around the internal region 51. In that case, the internal region 51 may be formed by using an ink other than the white ink.

The colored region 52 is a region having a predetermined thickness to be colored with the color ink. The modeling apparatus 100 ejects color inks of each color from each inkjet head of the head portion 110 and lands them around the internal region 51 to form a colored region 52 around the internal region 51 in each layer. At this time, the presence or absence of ejection of color ink of each color to each ejection position constituting the coloring region 52 (each position where the ink ejected from the inkjet head can be landed, which is specified according to the modeling resolution of the modeling apparatus 100). Various colors can be expressed in the colored region 52 by appropriately determining.

Further, if the amount of color ink deposited at each ejection position varies due to the difference in the colors to be expressed, an uneven ink layer is formed, and laminating such layers is a process of forming the model 50. It leads to deterioration of quality and strength. Therefore, in the present invention, by ejecting the clear ink mainly at the ejection position where the color ink is not ejected by the method described later, the layer is flattened and the amount of the clear ink used is suppressed.

In addition, a region other than the internal region 51 and the colored region 52 may be further formed according to the quality or the like required for the modeled object 50. For example, a transparent region (internal clear region) may be formed by ejecting clear ink between the internal region 51 and the colored region 52. By forming the internal clear region, for example, it is possible to prevent the ink from being mixed between the internal region 51 and the colored region 52. Further, a transparent region (external clear region) may be formed by ejecting clear ink around the colored region 52. By forming the outer clear region, for example, the outer surface of the modeled object 50 can be protected.

The modeling device 100 may model the modeled object 50 and, if necessary, form a support layer 60 around it. The support layer 60 is, for example, a laminated structure that supports the modeled object by surrounding the outer circumference of the modeled object 50 being modeled, and is around when the modeled object 50 alone cannot maintain a stable posture. By forming in, it is possible to stabilize the posture of the modeled object 50 during modeling. When the support layer 60 is formed, it is formed together with the modeled object 50 using a known material for the support layer that can be easily removed, and is removed after the modeling of the modeled object 50 is completed.

As shown in FIG. 1, for example, the modeling device 100 includes a head unit 110, a modeling table 120, a scanning drive unit 130, and a control unit 140. However, the modeling device 100 does not necessarily have to be physically integrally configured. For example, one or a plurality of functional units are cut out as separate devices, and information is transmitted and received integrally in wired communication or wireless communication. It may be configured to function.

Further, except for the points described below, the modeling apparatus 100 may have the same or the same configuration as the known modeling apparatus. Specifically, except for the points described below, the modeling apparatus 100 is the same as or similar to a known modeling apparatus that performs modeling by ejecting droplets that are the material of the modeled object 50 using an inkjet head. It may have features. In addition to the configurations shown in the figure, the modeling apparatus 100 may further include various configurations necessary for modeling the modeled object 50, for example.

The head portion 110 is a portion that discharges the material of the modeled object 50 (material for the modeled object). The material of the modeled object 50 is specifically an ink, and more specifically, for example, an ink that cures according to a predetermined condition. The head unit 110 includes a plurality of inkjet heads 111, and ejects predetermined ink from each inkjet head to each ejection position constituting an ink layer in accordance with control by a control unit 140 described later. Each discharge position is determined according to the modeling resolution of the modeling device 100. Then, the ink landed at each ejection position is cured according to a predetermined condition to form an ink layer. In this example, as an ink that cures according to a predetermined condition, an ultraviolet curable ink (UV ink) that cures from a liquid state by irradiation with ultraviolet rays is used.

Further, in addition to the ink used as the material of the modeled object 50, the head portion 110 discharges the ink used as the support material which is the material of the support layer 60, if necessary. As a result, the head portion 110 forms a support layer 60 around the modeled object 50.

The configuration of the head portion 110 will be described in more detail. FIG. 3 shows an example of the configuration of the head portion 110. In this example, the head portion 110 has a plurality of inkjet heads 111, a plurality of ultraviolet light sources 112, and a flattening roller 113. Further, as a plurality of inkjet heads 111, as shown in the figure, there are an inkjet head 111s, an inkjet head 111w, an inkjet head 111y, an inkjet head 111m, an inkjet head 111c, an inkjet head 111k, and an inkjet head 111t. These plurality of inkjet heads 111 are examples of ejection heads, and are arranged, for example, by aligning their positions in the sub-scanning direction and arranging them side by side in the main scanning direction. Further, each inkjet head has a nozzle row in which a plurality of nozzles are arranged in a predetermined nozzle row direction on a surface facing the modeling table 120. Further, in this example, the nozzle row direction is a direction parallel to the sub-scanning direction.

The inkjet head 111s is an inkjet head for a support material that ejects ink used as a support material. As the support material, for example, a known material for the support layer can be preferably used. Further, among the plurality of inkjet heads 111 in the head portion 110, the inkjet heads other than the inkjet heads 111s eject ink which is a material of the modeled object 50. The ink used as the material of the modeled object 50 is an ink that constitutes a part of the modeled object when the modeled object 50 is completed.

The inkjet head 111w is an inkjet head for white ink that ejects white (W color) ink. The white ink is an example of a light-reflecting ink, and is used, for example, when forming a region having a property of reflecting light (light-reflecting region) in the modeled object 50. In the example shown in FIG. 2, the internal region 51, which is a region constituting the interior of the modeled object 50, is formed of white ink so that the internal region 51 functions as a light reflection region.

The inkjet head 111y, the inkjet head 111m, the inkjet head 111c, and the inkjet head 111k are color ink inkjet heads used when modeling the colored region 52 of the modeled object 50. More specifically, the inkjet head 111y ejects yellow (Y color) ink. The inkjet head 111m ejects magenta (M color) ink. The inkjet head 111c ejects cyan (C color) ink. Further, the inkjet head 111k ejects black (K color) ink. Further, in this example, each color of CMYK is an example of a process color used for full-color expression by the subtractive color mixing method.

The inkjet head 111t is a clear ink inkjet head that ejects clear ink. The clear ink is, for example, a clear color ink that is colorless and transparent (T) with respect to visible light. The clear ink is used when modeling the colored region 52 of the modeled object 50 or the like.

For the color ink inkjet head and the clear ink inkjet head, a head (binary head) in which only one type of ejection amount can be set at a normal ejection timing may be adopted, if necessary. A head (multi-value head) that can be set by selecting a plurality of types of discharge amounts (dot size) may be adopted.

The plurality of ultraviolet light sources 112 are light sources (UV light sources) for curing the ink, and generate ultraviolet rays for curing the ultraviolet curable ink. Further, in this example, each of the plurality of ultraviolet light sources 112 is arranged on one end side and the other end side of the head portion 110 in the main scanning direction so as to sandwich an array of inkjet heads between them. As the ultraviolet light source 112, for example, a UV LED (ultraviolet LED) or the like can be preferably used. It is also conceivable to use a metal halide lamp, a mercury lamp, or the like as the ultraviolet light source 112.

The flattening roller 113 is a flattening means for flattening a layer of ink formed by ink ejected from each inkjet head. The flattening roller 113 flattens the ink layer by contacting the surface of the ink layer and removing a part of the ink before curing in a predetermined scanning cycle (for example, during the main scanning operation). , Adjust the thickness of the ink layer to a preset thickness.

By using the head portion 110 having the above configuration, the ink layer constituting the modeled object 50 can be appropriately formed. Further, by forming a plurality of layers of ink in layers, the modeled object 50 can be appropriately modeled.

The modeling table 120 is a trapezoidal member that supports the modeling object 50 being modeled, is arranged at a position facing the inkjet head in the head portion 110, and the modeled object 50 and the support layer 60 being modeled are placed on the upper surface. do. Further, in this example, the modeling table 120 has a configuration in which at least the upper surface can be moved in the stacking direction (Z direction in the drawing), and is driven by the scanning drive unit 130 to model the modeled object 50. At least the upper surface is moved as the process progresses. The laminating direction is the direction in which the ink layers are laminated in the additive manufacturing method. Further, in this example, the stacking direction is a direction orthogonal to the main scanning direction (Y direction in the drawing) and the sub scanning direction (X direction in the drawing) set in advance in the modeling apparatus 100.

The scanning drive unit 130 is a drive unit that causes the head unit 110 to perform a scanning operation that moves relative to the modeled object 50 being modeled. In this case, moving relative to the modeled object 50 being modeled means, for example, moving relative to the modeling table 120. Further, having the head portion 110 perform a scanning operation means, for example, causing the inkjet head of the head portion 110 to perform a scanning operation. Further, in this example, the scanning drive unit 130 causes the head unit 110 to perform a main scanning operation (Y scanning), a sub-scanning operation (X scanning), and a stacking direction scanning (Z scanning) as scanning operations.

The main scanning operation is an operation of ejecting ink while moving in the main scanning direction relative to the modeled object 50 being modeled. The sub-scanning operation is an operation of moving relative to the modeled object 50 being modeled in the sub-scanning direction orthogonal to the main scanning direction. The sub-scanning operation can also be considered as an operation of moving relative to the modeling table 120 in the sub-scanning direction by a preset feed amount. Further, the stacking direction scanning is an operation of moving the head portion 110 in the stacking direction relative to the modeled object 50 being modeled. The scanning drive unit 130 adjusts the relative position of the inkjet head with respect to the modeled object 50 being modeled in the stacking direction by causing the head unit 110 to scan in the stacking direction in accordance with the progress of the modeling operation. With such a configuration, the modeled object 50 can be appropriately modeled by the additive manufacturing method.

The control unit 140 has a configuration including a processor and the like, generates a slice image, determines an ejection position for landing each ink ejected by each inkjet head, and ejects each ink to each ejection position by each inkjet head. Perform control and so on.

The control unit 140 includes a slice image generating means 141, a color ink ejection position determining means 142, a clear ink ejection position determining means 143, and a layer forming means 144. The processing performed by each of these means can be realized by the processor. Specifically, each process can be realized by a processor that operates based on information such as a program and a memory that stores information such as a program in which the contents of each process are described. In the processor, for example, the function of each means may be realized by individual hardware, or the function of each means may be realized by integrated hardware. As the processor, various processors such as a CPU, GPU, and DSP can be used. As the memory, for example, a semiconductor memory such as SRAM or DRAM, a magnetic storage device such as a hard disk device, an optical storage device, or the like can be used. The memory stores instructions that can be read by a computer, and when the instructions are executed by the processor, processing of each means of the control unit 140 is realized.

Subsequently, the processing carried out by each means included in the control unit 140 will be described. The processing flow is shown in FIG.

Prior to executing the forming operation of the modeled object 50, the slice image generating means 141 generates a plurality of slice images showing the cross-sectional shape and color scheme of each layer of the modeled object 50 at different positions in a predetermined stacking direction. After converting to the resolution and color system according to the modeling device 100, the plates are separated for each color represented by the ink of each color used in the modeling device 100 (S1: slice image generation step).

Specifically, first, the modeled object data indicating the modeled object 50 is input (S1-1). The modeled object data is data showing the three-dimensional shape of the modeled object 50, the color of the surface, the orientation at the time of modeling, and the like. In the modeled object data, the surface color may be represented by an arbitrary color system such as an RGB color system or a CMYK color system that does not depend on the modeling device 100.

Subsequently, the slice image generating means 141 generates a plurality of slice images showing the cross-sectional shape and color scheme of each layer of the modeled object 50 at different positions in the predetermined stacking direction based on the modeled object data (S1-). 2). Specifically, the modeled object data is sliced in the stacking direction with the thickness of the ink layer, the cross-sectional shape and the surface color are extracted from each sliced portion, and the surface color is colored to have a predetermined thickness. A slice image showing the cross-sectional shape of the internal region 51 and the colored region 52, the color scheme of the colored region 52, and the like is generated by processing such as providing the region 52 around the internal region 51. Each slice image corresponds to each of a plurality of layers of ink formed during the modeling of the modeled object.

Subsequently, when the resolution of the slice image is different from the modeling resolution of the modeling device 100, the slice image generating means 141 converts it to the modeling resolution of the modeling device 100 (S1-3).

Further, when the color expressed in the colored region 52 of the slice image is a color that does not depend on the modeling device 100, the slice image generating means 141 converts the color into a color that matches the color ink of each color used in the modeling device 100. Do (S1-4).

Specifically, for example, first, for the color expressed in the coloring region 52 of the slice image in a format independent of the modeling apparatus 100, color conversion to the Lab color system is performed based on the input profile prepared in advance. .. The input profile referred to here is, for example, an ICC profile that associates the colors used in the modeled object data with the color space of the Lab color system. Using this, for example, the color represented in the model data in the RGB color system or the CMYK color system is converted into the color expressed in the Lab color system.

After performing the color conversion to the Lab color system, the slice image generation means 141 is used in the modeling device 100 by using the device profile prepared in advance according to the characteristics of the modeling device 100 (depending on the modeling device 100). ) Perform color conversion according to the color of the color ink. The device profile referred to here is, for example, an ICC profile that associates the color space of the Lab color system with the color of the color ink used in the modeling apparatus 100. Using this, the color expressed in the Lab color system is converted into the color of the color ink used in the modeling apparatus 100 (for example, the color of the CMYK color system).

In addition, when considering simply generating modeling execution data based on modeling object data, it is also possible to perform color conversion by a simpler method without performing color conversion using a profile such as an ICC profile. Conceivable. That is, for example, it is conceivable to formally convert a color represented by the RGB color system in the modeled object data into a color represented by the CMYK color system according to a certain conversion formula or the like.

However, when the color conversion is performed by such a simple method, it may be difficult to appropriately express a desired color in the modeled object 50. For example, when modeling a three-dimensional model 50, the color gamut (gamut) that can be expressed by a combination of inks of the same color is usually smaller than that when printing a two-dimensional image. Therefore, if color conversion is performed by a simple method without using an ICC profile or the like, color crushing or the like is likely to occur. Therefore, by performing color conversion using a device profile or the like that matches the ink to be used, color conversion can be appropriately performed with higher accuracy.

Subsequently, the slice image generation means 141 separates the slice image of each layer after performing these processes for each color represented by the ink of each color (S1-5).

Specifically, when each pixel of the colored region 52 of the sliced image is represented by, for example, a CMYK color system, the separation plate corresponds to the ink of each color of C, M, Y, and K4. Generate a sheet of separation slice image. Further, since at least the internal region 51 is formed in white, a separation slice image corresponding to the white ink is generated. Further, when the support layer 60 is formed, a separation slice image corresponding to the ink used as the support material is generated.

The color ink ejection position determining means 142 determines whether or not each of the plurality of colors of ink for coloring is ejected to each ejection position constituting the ink layer by quantization processing based on the slice image corresponding to the ink layer. (S2: Color ink ejection position determination step). Specifically, each ink layer constituting the modeled object 50 is subjected to a quantization process on each of the divided slice images corresponding to the inks of each of the separated colors.

The quantization process here means that for each pixel constituting the separation slice image, the gradation of light and shade of the color expressed in multiple gradations is reduced by using, for example, the error diffusion method or the dither method. It is a process to convert to.

Further, the less gradation referred to here is when the inkjet head for color ink provided in the head unit 110 is a head (binary head) in which only one type of ejection amount can be set at a normal ejection timing. Is two gradations corresponding to with and without ejection. In this case, the separation slice image in which each pixel is expressed in multiple gradations is converted into a separation slice image in which each pixel is expressed in two gradations.

On the other hand, when the color ink inkjet head included in the head unit 110 is a head (multi-valued head) in which a plurality of types of ejection amounts (dot sizes) can be selected and set, for example, large, medium, and small dots If the size can be selected, the smaller gradations are four gradations corresponding to with ejection (large dot size), with ejection (medium dot size), with ejection (small dot size), and without ejection. Therefore, in this case, a separation slice image in which each pixel is represented by multiple gradations, for example, each pixel has two gradations (that is, for each of large dot size, medium dot size, and small dot size). Convert to 3 separation slice images represented by (with and without dots).

The order shown in the processing flow of the slice image generation means 141 in FIG. 4 is not limited to this, and the included processing contents may be appropriately changed within an executable range.

The clear ink ejection position determining means 143 is a clear ink that is transparent ink to each ejection position based on the presence or absence of ejection of each color ink for coloring at each ejection position determined by the color ink ejection position determining means 142. (S3: Clear ink ejection position determination step).

A first specific example of a method for determining the necessity of discharging clear ink will be described with reference to FIG. In each of FIGS. 5 (a) and 5 (b), the pixels Pc1, Pc2 at the same position in the separation slice image divided into four sheets corresponding to each of the four color inks c1, c2, c3, and c4. Pc3 and Pc4 are extracted, and the presence or absence of ejection of color ink of each color to the ejection position corresponding to the pixel position can be identified by coloring the pixels Pc1, Pc2, Pc3, Pc4 with black or white. Specifically, white indicates that there is no ejection of color ink to the corresponding ejection position, and black indicates that there is ejection.

Assuming that the maximum number of color inks ejected to one ejection position is one, it is cleared at the position where any color ink (here, color ink c1) is ejected as illustrated in FIG. 5 (a). At the ejection position where no ink is ejected and no color ink of any color is ejected as illustrated in FIG. 5 (b), the clear ink t is adjusted so that the position where the color ink is ejected and the thickness of the layer are matched. By determining that the ink is ejected, the thickness of the ink layer can be made uniform.

A second specific example of the method for determining whether or not the clear ink needs to be ejected will be described with reference to FIG. Similar to FIGS. 5 (a) and 5 (b), FIGS. 6 (a), 6 (b), and (c) are divided into four plates corresponding to each of the four color inks c1, c2, c3, and c4. Pixels Pc1, Pc2, Pc3, Pc4 at the same position in the separated slice image are extracted, and the presence or absence of ejection of color ink of each color to the ejection position corresponding to the pixel position is determined by the pixels Pc1, Pc2, Pc3, Pc4. It is made identifiable by the black or white coloring of.

In the example of FIG. 5, it is assumed that the maximum number of color inks ejected to one ejection position is one, but in the CMYK color system, for example, two colors are ejected to one ejection position depending on the color to be expressed. In some cases. At this time, assuming that the clear ink inkjet head is a binary head, the clear ink is cleared at the ejection position where the two color inks (here, the color inks c1 and c3) are ejected as illustrated in FIG. 6A. By ejecting clear ink t at the ejection position where only one color ink (color ink c1 in this case) is ejected without ejecting ink as illustrated in FIG. 6B, the thickness of the layer Can be matched with the ejection position where the two color inks are ejected. On the other hand, as illustrated in FIG. 6 (c), at the ejection position where no color ink of any color is ejected, only the same amount of clear ink t as in the case of FIG. 6 (b) can be ejected, and two colors are ejected. The thickness of the layer is insufficient with respect to the ejection position where the color ink of. However, even if the thickness is insufficient for some of the ejection positions in this way, for example, when the flattening roller 113 flattens the ink layer at a predetermined scanning cycle, the ink layer is excessively ejected to other ejection positions. It has been experimentally confirmed that the shortage is almost completely compensated by the inflow of ink. Therefore, when a maximum of two colors of color ink are ejected to one ejection position, the clear ink inkjet head is a binary head by determining the clear ink ejection position by the method illustrated in FIG. However, it is possible to make the thickness of the ink layer uniform.

A third specific example of the method for determining the necessity of discharging clear ink will be described with reference to FIG. 7. 7 (a), (b), and (c) correspond to the four color inks c1, c2, c3, and c4, respectively, as in FIGS. 6 (a), (b), and (c). Pixels Pc1, Pc2, Pc3, and Pc4 at the same position in the separation slice image divided into sheets are extracted, and the presence or absence of ejection of color ink of each color to the ejection position corresponding to the pixel position is determined by the pixels Pc1, Pc2. , Pc3, Pc4 can be identified by coloring black or white.

In the example of FIG. 6, the case where the color ink ejected to one ejection position has a maximum of two colors and the clear ink inkjet head is a binary head has been described, but FIG. 7 shows the case where the clear ink is used. This is an example of a case where the inkjet head is a multi-value head. In this case, as illustrated in FIG. 7 (a), the clear ink is not ejected to the ejection position where the two color inks (color inks c1 and c3 in this case) are ejected, and is illustrated in FIG. 7 (b). As shown in FIG. 7 (c), the same amount of clear ink tS as the color ink inkjet head is ejected to the ejection position where only one color ink (color ink c1 in this case) is ejected. As described above, by ejecting twice the amount of clear ink tM as the clear ink tS at the ejection position where no color ink of any color is ejected, the thickness of the ink layer can be made uniform.

A fourth specific example of the method for determining the necessity of discharging clear ink will be described with reference to FIGS. 8 and 9. 8 (a), (b), (c) and 9 (a), (b), (c) show, for example, when both the color ink inkjet head and the clear ink inkjet head are multi-valued heads. In the case where ink can be ejected with three types (for example, 1x, 2x, 3x) of ink ejection amount (dot size) for each inkjet head, each of the four color inks c1, c2, c3, and c4 Pel Pc1S (dot size S of color ink c1 (1x dot size, the same applies hereinafter)) and Pc2S (color ink) at the same position in the separation slice image divided into a total of 12 sheets corresponding to 3 types of dot sizes. c2 dot size S), Pc3S (color ink c3 dot size S), Pc4S (color ink c4 dot size S), Pc1M (color ink c1 dot size M (double dot size, the same applies hereinafter)), Pc2M (dot size M of color ink c2), Pc3M (dot size M of color ink c3), Pc4M (dot size M of color ink c4), Pc1L (dot size L of color ink c1 (three times the dot size, below) (Same as above)), Pc2L (dot size L of color ink c2), Pc3L (dot size L of color ink c3), and Pc4L (dot size L of color ink c4) are extracted and transferred to the ejection position corresponding to the pixel. The presence or absence of ejection of color ink of each color and each dot size is indicated by black or white in two gradations of pixels Pc1S, Pc2S, Pc3S, Pc4S, Pc1M, Pc2M, Pc3M, Pc4M, Pc1L, Pc2L, Pc3L, and Pc4L. It is identifiable based on the coloring.

In this case, when the dot size is expressed by a numerical value whose value increases as the dot size increases, the dot size of each color ink ejected to the ejection position determined by the color ink ejection position determining means 142. The dot size of the clear ink discharged to the discharge position is determined so that the sum of the sum of the values of and the dot size value of the clear ink discharged to the discharge position is as close as possible to a predetermined reference value. Thereby, the thickness of the formed ink layer can be made uniform.

FIG. 8 is an example when the predetermined reference value is 3. When the dot sizes S, M, and L are represented by, for example, numerical values 1, 2, and 3, in the example of FIG. 8A, the color ink c1 having a dot size of 1 and the color ink c3 having a dot size of 2 are ejected. The total dot size is 3 because it is ejected to the position. Therefore, since the dot size has reached a predetermined reference value only with the color ink, it is determined that the clear ink is not ejected.

Further, in the example of FIG. 8B, since the color ink c1 having a dot size of 3 is ejected to the ejection position, the total dot size is 3. Therefore, since the dot size has reached a predetermined reference value only with the color ink, it is determined that the clear ink is not ejected.

Further, in the example of FIG. 8C, since the color ink is not ejected at the ejection position, the total dot size is 0. Therefore, in this case, it is determined that the clear ink having a dot size of 3 is ejected.

On the other hand, FIG. 9 shows an example when the predetermined reference value is 6. When the dot sizes S, M, and L are represented by numerical values 1, 2, and 3, in the example of FIG. 9A, the color ink c1 having a dot size of 3 and the color ink c3 having a dot size of 3 are ejected positions. The total dot size is 6 because it is discharged to. Therefore, since the dot size has reached a predetermined reference value only with the color ink, it is determined that the clear ink is not ejected.

Further, in the example of FIG. 9B, since the color ink c1 having a dot size of 3 is ejected to the ejection position, the total dot size is 3. Therefore, in this case, it is determined that the clear ink having a dot size of 3 is ejected.

Further, in the example of FIG. 9C, since the color ink is not ejected at the ejection position, the total dot size is 0. Therefore, in this case, it is desirable to eject clear ink having a dot size of 6, but since the maximum dot size that can be ejected by the clear ink inkjet head here is 3, the dot size is 6 with respect to the ejection position. The thickness of the layer is insufficient. However, even if the thickness is insufficient for some of the ejection positions in this way, for example, when the flattening roller 113 flattens the ink layer at a predetermined scanning cycle, the ink layer is excessively ejected to other ejection positions. It has been experimentally confirmed that the shortage is almost completely compensated by the inflow of ink. Therefore, in this case, the dot size of the clear ink may be determined to be 3. If the clear ink inkjet head included in the head unit 110 can adopt the multipath method, it is a technique to eject clear ink having a dot size of 3 at the same ejection position twice, for example, on the outward route and the return route. It is possible. That is, according to this method, clear ink having a dot size of 6 can be ejected to make the thickness of the ink layer uniform.

In the clear ink ejection position determining means 143, the necessity of ejecting clear ink to each ejection position determined as described above is expressed, for example, in two gradations (that is, with ejection and without ejection) for each pixel. A slice image for clear ink is generated for each layer. When the clear ink inkjet head is a multi-value head, a slice image for clear ink is generated for each dot size.

The layer forming means 144 ejects each of the separation slice images of each color after the quantization process generated by the color ink ejection position determining means 142 and the clear ink slice images generated by the clear ink ejection position determining means 143. Information on the presence / absence of ejection of coloring ink to the position and the necessity of ejection of clear ink is read, and the head unit 110 and the scanning drive unit 130 are controlled according to the information to provide the color ink head and the clear ink head for each color. (S4: Layer formation step). As a result, each ink layer can be formed in sequence, and the modeled object 50 can be modeled by laminating the formed layers.

Since the modeling apparatus 100 of the present invention described above determines the necessity of ejecting clear ink for each ejection position and ejects clear ink according to the determination, the amount of clear ink used at the time of forming each layer can be saved. At the same time, the amount of ink scraped off during flattening can be reduced, so that deterioration of the quality of the surface of the modeled object can be suppressed.

The present invention is not limited to the above embodiments. The above-described embodiment is an example, and any object having substantially the same configuration as the technical idea described in the claims of the present invention and exhibiting the same effect and effect is the present invention. It is included in the technical scope of the invention. That is, it can be appropriately changed within the scope of the technical idea expressed in the present invention, and the form in which such a change or improvement is added is also included in the technical scope of the present invention.

50 ... Modeled object 51 ... Internal area 52 ... Colored area 60 ... Support layer 100 ... Modeling device 110 ... Head unit 111 ... Multiple inkjet heads 112 ... Ultraviolet light source 113 ... Flattening roller 120 ... Modeling table 130 ... Scanning drive unit 140 ... Control unit 141 ... Slice image generation means 142 ... Color ink ejection position determining means 143 ... Clear ink ejection position determining means 144 ... Layer forming means c1 to c4, c1S, c1M, c1L, c3M, c3L ... Color inks Pc1 to Pc4, Pc1S ~ Pc4S, Pc1M ~ Pc4M, Pc1L ~ Pc4L ... Pixel tS, tM, tL ... Clear ink

Claims (6)

Based on a plurality of slice images showing the cross-sectional shape and color scheme of each layer of the modeled object at different positions in a predetermined stacking direction, each layer is formed as an ink layer and laminated to form the modeled object. It ’s a device,
Based on the slice image corresponding to the layer, a color ink ejection position determining means for determining the presence or absence of ejection of each of a plurality of colors of ink for coloring to each ejection position constituting the layer by quantization processing.
Based on the presence or absence of ejection of each color ink for coloring to each ejection position determined by the color ink ejection position determining means, the necessity of ejecting clear ink, which is a transparent ink, to each ejection position is determined. Clear ink ejection position determining means to determine,
A color ink head capable of ejecting each of the plurality of color inks,
A clear ink head capable of ejecting the clear ink and
The layer is formed by ejecting ink of each color and clear ink to the ejection positions of the color ink and the clear ink head according to the determination by the color ink ejection position determining means and the clear ink ejection position determining means. And the layer forming means to form
A modeling device equipped with. The color ink ejection position determining means further determines the dot size of the ink to be ejected.
The clear ink ejection position determining means is determined by the color ink ejection position determining means to each ejection position based on the presence or absence of ejection of each of the plurality of colors of ink for coloring to each ejection position and the dot size. Determine the presence or absence of clear ink ejection and the dot size,
The color ink head and the clear ink head can each eject ink having a plurality of types of dot sizes.
The layer forming means is applied to the color ink head and the clear ink head to each of the ejection positions, and of each color of dot size according to the determination by the color ink ejection position determining means and the clear ink ejection position determining means. The modeling apparatus according to claim 1, wherein ink and clear ink are discharged. When the dot size is expressed by a numerical value whose value increases as the dot size increases, the clear ink ejection position determining means is colored to be ejected to the ejection position determined by the color ink ejection position determining means. The sum of the sum of the dot size values of the inks of each color for use and the dot size value of the clear ink ejected to the ejection position is ejected to the ejection position so as to be as close as possible to a predetermined reference value. The modeling apparatus according to claim 2, wherein the dot size of the clear ink is determined. Based on a plurality of slice images showing the cross-sectional shape and color scheme of each layer of the modeled object at different positions in a predetermined stacking direction, each layer is formed as an ink layer and laminated to form the modeled object. It ’s a method,
Based on the slice image corresponding to the layer, a color ink ejection position determination step of determining the presence or absence of ejection of each of the plurality of color inks for coloring to each ejection position constituting the layer by quantization processing.
Whether or not clear ink, which is a transparent ink, needs to be ejected to each ejection position is determined based on the presence or absence of ejection of each color ink for coloring to each ejection position determined in the color ink ejection position determination step. Clear ink ejection position determination step to determine and
The layer is formed by ejecting ink of each color and clear ink to each ejection position according to the determination in the color ink ejection position determination step and the clear ink ejection position determination step on the color ink head and the clear ink head. Layer formation steps and
The modeling method to execute. In the color ink ejection position determination step, the dot size of the ink to be ejected is further determined.
The clear ink ejection position determination step is performed on each ejection position based on the presence or absence of ejection of each of the plurality of color inks for coloring to each ejection position and the dot size determined in the color ink ejection position determination step. Determine the presence or absence of clear ink ejection and the dot size,
The color ink head and the clear ink head can each eject ink having a plurality of types of dot sizes.
The layer forming step is performed on the color ink head and the clear ink head to each of the ejection positions, and of each color of dot size according to the determination in the color ink ejection position determination step and the clear ink ejection position determination step. The modeling method according to claim 4, wherein ink and clear ink are discharged. When the dot size is expressed by a numerical value whose value increases as the dot size increases, the clear ink ejection position determination step is the coloring determined in the color ink ejection position determination step and ejected to the ejection position. The sum of the sum of the dot size values of the inks of each color for use and the dot size value of the clear ink ejected to the ejection position is ejected to the ejection position so as to be as close as possible to a predetermined reference value. The modeling method according to claim 5, wherein the dot size of the clear ink is determined.

Images