JP2016128254A - Image forming apparatus and production method of output object - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form an image in which glossiness is suppressed to be a specified value or lower.SOLUTION: There are provided a recording part 14 which discharges a liquid that solidifies under stimulation, an irradiation part 22 for solidifying the liquid discharged from the recording part 14, a drive part 25 for moving the recording part 14, a scan control part 28A which controls the drive part 25 so as to, in an image formation region of 1 where an image is formed, moves the recording part 14 and the irradiation part 22 along a sub-scan direction relative to an image formed object, and makes the recording part 14 scan at a plurality of times along a main scan direction relative to the image formed object, and a mat lamination control part 28C, in a case where a plurality of layers are formed, with an image formed by the scan control part 28A as one layer, an image is formed by scanning for an amount of a plurality of layers along the main scan direction relative to an image formation region of 1, and then, the recording part 14 is moved along the sub-scan direction relative to the image formed object, for performing image formation for the amount of scan frequency thereafter.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an image forming apparatus and an output product production method.

  An image forming method (three-dimensional object forming method) is known in which a three-dimensional image or a three-dimensional object is formed by ejecting ink using an ink jet method, forming a layer by drying or curing, and laminating the layers. . As one of image forming methods using an ink jet method, a method of repeating layer formation, curing, and lamination is known. Hereinafter, the “image” includes a three-dimensional image and a three-dimensional object.

  In this method, for example, a photocurable ink (for example, UV ink) that is cured by irradiating light (such as ultraviolet rays) onto a medium (image-formed object) from a nozzle is ejected and formed on the medium. The UV ink dots are fixed on the medium by irradiating the UV ink dots with light and curing them.

  For example, Patent Document 1 discloses printing by an inkjet printer that receives a page image divided into a plurality of surfaces from a host computer, and prints each surface image by superimposing a solid layer of ink on the same medium one by one. A method is disclosed.

  An image printed using UV ink by a conventional ink jet method has a problem of uneven glossiness that causes uneven glossiness. As one of the factors that cause this gloss nonuniformity, there is a difference in the amount of ink (also referred to as duty) per unit area ejected on the medium.

  That is, a difference in gloss occurs between a high gradation portion and a low gradation portion of the printed image, and gloss unevenness occurs when these are adjacent to each other. For example, in a portion where the gradation value is low (color is light) and the ink shot amount is small (low duty), the glossiness is high, the tone value is high (color is dark), and the ink shot amount is high (high duty). The glossiness is low at the portion.

  For this non-uniform glossiness, Patent Document 2 discloses that color ink and clear ink that are cured by light irradiation are ejected, and the amount of color ink (color duty) and the amount of clear ink that are ejected per unit area (color duty). With respect to the test patterns formed while changing the clear duty), the combination of the color duty and the clear duty when the glossiness reaches a predetermined magnitude is examined based on the glossiness measured for each of a plurality of types of patches. Thus, the relationship between the total amount of the color duty and the clear duty and the glossiness of the image printed by the discharged color ink and the clear ink is obtained, and the glossiness of the image becomes a predetermined value. Disclosed is a printing method for determining a clear duty in an area according to a color duty in an area in the image. It has been.

  This printing method changes the clear duty according to the color duty, and injects clear ink into the low clear duty in the high color duty part and the high clear duty into the high color duty part, and gloss unevenness We are trying to solve the problem.

  In recent years, in a printing method in which layer formation, curing, and lamination are repeated using photocurable ink, a glossy texture image is output with a low glossiness (for example, 60 ° glossiness of 7 or less). There is a demand for that.

  However, as in Patent Document 2, the printing method in which the color ink and the clear ink are applied to the same layer has a problem in that it is difficult to form an image with excellent gloss uniformity while keeping the gloss level low. This point will be described with reference to FIGS. 25 and 26. FIG.

  FIG. 25 is a graph showing the relationship between the ink application amount per unit area and each gloss level (20-degree glossiness, 60-degree glossiness, 85-degree glossiness). The ink application amount per unit area on the horizontal axis indicates a value obtained by multiplying Duty [%], which is the amount of ink per unit area, by an appropriate amount [pl]. As shown in a frame A in FIG. 25, it can be seen that the glossiness increases as the area where the ink application amount per unit area is small. Since the image includes a region where the amount of ink applied per unit region is large and a region where the ink is applied, a portion with high gloss and a portion with low gloss are generated.

  In Patent Document 2, as shown in FIG. 26, uniform gloss is achieved by controlling the clear duty. As indicated by an arrow B in FIG. 26, in the low color duty region, the glossiness can be reduced by using clear ink.

  However, as shown in FIG. 26, since the 60 degree glossiness when the color duty is 100% (maximum) is minimized, the glossiness when the color duty is 100% is uniform to achieve uniform glossiness. I have to make it. That is, with this printing method, the glossiness converges at about 10, and even when the appropriate amount of clear ink is increased, no further reduction in gloss can be achieved. For this reason, with this printing method, it has been impossible to form an image with excellent gloss uniformity while suppressing the gloss level to a low value of a predetermined value or less.

  SUMMARY An advantage of some aspects of the invention is that it provides an image forming apparatus capable of suppressing glossiness to a low value.

  In order to achieve this object, an image forming apparatus according to the present invention is an image forming apparatus that forms an image on an object to be imaged. The image forming apparatus discharges a liquid that is cured by a stimulus, and is discharged by the recording unit. In one image forming region where an image is formed, the recording unit and the curing unit are relative to the image forming object in a curing unit that cures the liquid, a drive unit that moves the recording unit, Formed by the scan control unit and the scan control unit that controls the drive unit to move the recording unit a plurality of times in the main scanning direction relative to the image forming object. In the case where a plurality of layers are formed with the image to be formed as one layer, an image is formed by scanning the number of the plurality of layers in the main scanning direction with respect to one image forming region, and then the recording portion is the image-formed object Siderun relative to Is moved in a direction in which comprises a mat stack controller to perform the image formation of the next number of scanning times, the.

  According to the present invention, the glossiness can be suppressed to a low value.

1 is a schematic configuration diagram of an image processing system. It is a functional block diagram of an image processing system. It is a figure which shows an example of the hardware constitutions of an image processing apparatus. 3 is a schematic diagram illustrating an example of a recording unit of the image forming apparatus. FIG. FIG. 10 is a schematic diagram illustrating another example of a recording unit of the image forming apparatus. FIG. 10 is a schematic diagram illustrating another example of a recording unit of the image forming apparatus. It is explanatory drawing of the nozzle distribution in the case of 2 scan printing. It is explanatory drawing of nozzle distribution in the case of 5 scan printing. It is explanatory drawing which shows the mode of the image formation by 2 scan printing. It is explanatory drawing which shows the mode of the image formation by a normal lamination system. FIG. 5 is an image diagram showing how dots formed in the first to sixteenth scans are landed when three layers are printed by a normal lamination method. It is the enlarged image figure which showed the mode of the lamination | stacking of the dot by a normal lamination system. It is explanatory drawing which shows the mode of the image formation by a mat | matte lamination system. FIG. 6 is an image diagram showing how dots formed in the first to sixteenth scans land when three layers are printed by the mat lamination method. It is the enlarged image figure which showed the mode of the lamination | stacking of the dot by a mat | matte lamination system. 6 is a flowchart illustrating an example of image forming method selection processing. It is a flowchart which shows the detail of the printing process by a mat | matte lamination system. It is a flowchart which shows the detail of the printing process by a normal lamination system. It is the graph which showed the relationship between the number of layers and 60 degree glossiness for every lamination | stacking system. It is the graph which showed the relationship between the number of layers and arithmetic mean roughness for every lamination system. It is a test chart in which a plurality of patches formed while changing the number of layers and the combination of the normal lamination method and the mat lamination method are formed. It is explanatory drawing which shows the combination of the mat | matte lamination | stacking system and normal lamination | stacking system about each patch of FIG. It is a gray scale chart about a black ink drop. It is a schematic diagram at the time of carrying out 3 layer printing using clear ink. It is a graph which shows the relationship between the ink application amount per unit area | region, and glossiness (20 degree, 60 degree | times, 85 degree | times). It is a graph which shows the relationship between color duty and 60 degree | times glossiness.

  Hereinafter, the configuration according to the present invention will be described in detail based on the embodiment shown in FIGS.

  The image forming apparatus according to the present embodiment is an image forming apparatus that forms an image on an object to be imaged (support P), and is a recording unit (recording unit 14) that discharges liquid (droplets 32) that is cured by stimulation. ), A curing unit (irradiation unit 22) that cures the liquid ejected by the recording unit, a driving unit (driving unit 25) that moves the recording unit, and a single image forming region in which an image is formed. And the curing unit are moved in the sub-scanning direction relative to the image forming object, and the driving unit is controlled to scan the recording unit a plurality of times in the main scanning direction relative to the image forming object. When forming a plurality of layers by using the scan control unit (scan control unit 28A) and the image formed by the scan control unit as one layer, the number of layers in the main scanning direction is scanned for one image forming region. After the image is formed, the recording Relatively sub-scan direction to move those having matt laminated controller to perform the image formation of the next number of scanning times (the mat laminated controller 28C), the relative things. In addition, the code | symbol in embodiment and the example of application are shown in a parenthesis.

<Image processing system>
FIG. 1 is a schematic configuration diagram illustrating an example of an image processing system 10. The image processing system 10 includes an image processing device 12 and an image forming device 30. The image processing apparatus 12 and the image forming apparatus 30 are connected to be communicable. Note that the “image forming apparatus” in a broad sense includes any of the image processing system 10 including the image processing apparatus 12 and the image forming apparatus 30, the image processing apparatus 12 alone, and the image forming apparatus 30 alone.

  The image forming apparatus 30 includes a recording unit 14, an operation stage 16, and a driving unit 25. The recording unit 14 is an inkjet carriage including a plurality of heads 18 (recording heads) provided with a plurality of nozzles, and records dots by discharging droplets from the nozzles of the head 18. The nozzles are provided on the surface of the recording unit 14 that faces the operation stage 16.

  The droplets are ink droplets and additional droplets. The ink droplets are ink droplets (color ink) containing a color material used for image formation.

  The additional droplet is a color droplet that does not affect the image. The additional droplet is, for example, white or transparent (clear ink). Further, the additional liquid droplets may have the same color as the support P that is the image forming object. The support P is an image forming object of an image with ink droplets. The support P is, for example, a recording medium. Further, the support P itself may be formed on the operation stage 16 by discharging droplets using an inkjet method or the like.

  The ink droplets and additional droplets are stimulus curable. The stimulus is, for example, light (ultraviolet light, infrared light, etc.), heat, electricity or the like. In the present embodiment, the case where the ink droplet and the additional droplet have ultraviolet curable properties will be described as an example. The ink droplet and the additional droplet are not limited to the form having ultraviolet curable properties.

  An irradiation unit 22 is provided on the surface of the recording unit 14 facing the operation stage 16. The irradiation unit 22 irradiates the support P with light having a wavelength that cures the ink droplets and additional droplets ejected from the nozzles. The irradiation unit 22 irradiates ultraviolet rays, for example.

  The operation stage 16 holds the support P. The drive unit 25 moves the recording unit 14 and the operation stage 16 in the vertical direction (the arrow Z direction in FIG. 1), the main scanning direction X perpendicular to the vertical direction Z, and the sub-direction perpendicular to the vertical direction Z and the main scanning direction X. It is moved relatively in the scanning direction Y. In the present embodiment, the plane composed of the main scanning direction X and the sub-scanning direction Y corresponds to the XY plane along the surface facing the recording unit 14 in the operation stage 16.

  The drive unit 25 includes a first drive unit 23 and a second drive unit 24. The first drive unit 23 moves the recording unit 14 in the vertical direction Z, the main scanning direction X, and the sub-scanning direction Y. The second drive unit 24 moves the operation stage 16 in the vertical direction Z, the main scanning direction X, and the sub-scanning direction Y. The image forming apparatus 30 may be configured to include one of the first drive unit 23 and the second drive unit 24.

  FIG. 2 is a functional block diagram of the image processing system 10. The image forming apparatus 30 includes a recording unit 14, a driving unit 25, and an irradiation unit 22.

  The image processing device 12 includes a main control unit 13 and a recording control unit 28. The main control unit 13 is a computer that includes a CPU (Central Processing Unit) and the like, and controls the entire image processing apparatus 12. Note that the main control unit 13 may be configured by other than a general-purpose CPU. For example, the main control unit 13 may be configured with a circuit or the like. The recording control unit 28 is also a computer configured to include a CPU (Central Processing Unit) and the like, similarly to the main control unit 13, and even if it is the same computer as the main control unit 13, it is provided separately. May be.

  The main control unit 13 includes a data reception unit 12A, a data creation unit 12B, a data output unit 12C, and a determination unit 12D. A part or all of the data reception unit 12A, the data creation unit 12B, the data output unit 12C, the determination unit 12D, and the recording control unit 28 is realized by causing a processing device such as a CPU to execute a program, that is, by software. Alternatively, it may be realized by hardware such as an IC (Integrated Circuit), or may be realized by using software and hardware in combination.

  The data receiving unit 12A receives image data. The image data is information such as the shape and color of the image to be formed. The data receiving unit 12 </ b> A may acquire image data from an external device via a communication unit, or may acquire image data from a storage unit provided in the image processing device 12.

  The data creating unit 12B performs predetermined data processing such as mask processing on the image data received by the data receiving unit 12A.

  The data output unit 12C outputs the image data created by the data creation unit 12B to the image forming apparatus 30.

  Based on the image data created by the data output unit 12C, the recording control unit 28 ejects the liquid droplets 32 corresponding to each pixel from the head 18, so that the recording unit 14, the driving unit 25, And controls the irradiation unit 22.

  The recording control unit 28 includes a scan control unit 28A, a normal stacking control unit 28B, and a mat stacking control unit 28C, and performs control to form an image by a multi-scan method, a normal stacking method, and a mat stacking method, which will be described later. Further, a patch forming unit 28D for forming a test chart to be described later is provided.

  The determination unit 12D determines which of the normal lamination method and the mat lamination method is used for printing based on information input to the determination unit 12D.

  In the present embodiment, the image processing system 10 includes an image processing apparatus 12 and an image forming apparatus 30 that are communicably connected. The image processing apparatus 12 is included in the image forming apparatus 30. May be. Further, in the configuration in which the image processing system 10 includes the image processing apparatus 12 and the image forming apparatus 30 (FIG. 2), the image forming apparatus 30 includes the recording control unit 28, and the recording control unit 28 includes the image processing apparatus 12. Image data may be received from the data output unit 12C.

  Next, the hardware configuration of the image processing apparatus 12 will be described. FIG. 3 shows an example of a block diagram showing the hardware configuration of the image processing apparatus 12. The image processing apparatus 12 includes an input unit 130 for inputting data, a display unit 131 such as a display, a communication unit 132 for performing data communication, a CPU 133 as a control unit that controls the entire apparatus, and a CPU 133. The RAM 134 is used as a work area, and the recording unit 135 stores various programs for operating the CPU 133.

  Examples of the input unit 130 include a keyboard having cursor keys, numeric input keys, various function keys, and the like. Examples of the input unit 130 include a mouse and a slice pad for performing key selection on the display screen of the display unit 131, and the like. This is a user interface for a user to give an operation instruction to the CPU 133 or to input data.

  Examples of the display unit 131 include a CRT and an LCD, and display is performed according to display data input from the CPU 133. The communication unit 132 is for data communication with the outside, and is for data communication with the image forming apparatus 30 through a predetermined communication interface.

  The CPU 133 is a central control unit that controls the entire apparatus according to a program stored in the recording unit 135, and the input unit 130, the display unit 131, the communication unit 132, the RAM 134, and the recording unit 135 are connected to the CPU 133. It controls data communication, reading of application programs by accessing the memory, reading / writing of various data, data / command input, display, and the like.

  Further, the CPU 133 sends image data for forming an image to the image forming apparatus 30 via the communication unit 132 based on the image data input from the input unit 130 or the image data stored in the recording unit 135. To do.

  The RAM 134 includes a work memory that stores designated programs, input instructions, input data, processing results, and the like, and a display memory that temporarily stores display data to be displayed on the display screen of the display unit 131.

  The recording unit 135 stores various programs and data such as an OS program executable by the CPU 133 (for example, an operating system Windows (registered trademark) of Microsoft Corporation) and a printer driver corresponding to the image forming apparatus 30. As the recording unit 135, for example, an optical, magnetic, or electrical recording medium such as a hard disk, a CD-ROM, or a DVD-ROM can be used.

  Various programs are stored in the recording unit 135 in a data format readable by the CPU 133. The various programs may be recorded in advance in the recording unit 135 or may be downloaded via a communication line such as the Internet and stored in the recording unit 135.

<Image forming apparatus>
Next, details of the image forming apparatus 30 will be described. The image forming apparatus 30 forms an image by an optical modeling method that discharges ink (photocurable ink) of a photocurable resin and irradiates light to cure the photocurable resin.

(Recording part)
As shown in FIG. 4, the recording unit 14 in the image forming apparatus 30 is a carriage in which a plurality of nozzles 19 are arranged in a predetermined direction. Each nozzle 19 ejects an ink droplet, an additional droplet, or a mixed liquid of an ink droplet and an additional droplet as the droplet 32. The configuration for discharging the nozzle 19 and droplets is the same as that of a known ink jet system.

  In the present embodiment, the heads 18K, 18C, 18M, 18Y, 18W, and 18T (the head 18 when not distinguished) are arranged in a predetermined direction. Each head 18 has nozzles 19K, 19C, 19M, 19Y, 19W, and 19T (nozzles 19 when not distinguished) that discharge ink droplets. Nozzle 19K is a black ink droplet, nozzle 19C is a cyan ink droplet, nozzle 19M is a magenta ink droplet, nozzle 19Y is a yellow ink droplet, nozzle 19W is a white additional droplet, and nozzle 19T is a transparent additional droplet. Discharge.

  By ejecting the droplet 32 from the nozzle 19, dots 34 corresponding to the droplet 32 are formed on the support P, and the image 17 is formed. In addition, the droplets 32 are stacked and discharged, so that the dots 34 are stacked and the three-dimensional image 17 is formed.

  In the present embodiment, irradiation units 22 are provided at both ends in the arrangement direction of the heads 18K, 18C, 18M, 18Y, 18W, and 18T. By irradiating light from the irradiation unit 22 to the droplets 32 discharged from each nozzle 19, the droplets 32 are cured.

  The irradiation unit 22 is preferably arranged in the vicinity of the nozzle 19. By disposing the irradiation unit 22 in the vicinity of the nozzle 19, it is possible to shorten the curing time from when the droplet 32 ejected from the nozzle 19 adheres to the support P side until it cures. For this reason, a higher definition image can be formed.

  In addition, the number of the irradiation parts 22 and the installation position of the irradiation parts 22 are not limited to the form shown in FIG. For example, as shown in FIG. 5, the irradiation unit 22 may be provided at a position downstream of the recording unit 14 in the main scanning direction X.

  FIG. 4 shows a case where each of the heads 18 discharges one color (one type) of droplets 32. However, the present invention is not limited to this. For example, as shown in FIG. The head 18 may include two or more nozzles 19. Further, the nozzle 19 may eject a mixed droplet of a plurality of types of droplets 32. Further, the color of ink ejected from the recording unit 14 is not limited to black, cyan, magenta, and yellow. Further, the types of droplets 32 ejected from the recording unit 14 are not limited to six types (black, cyan, magenta, yellow, white, and transparent).

  Further, as shown in FIG. 1, in the image forming apparatus 30, the recording unit 14 and the support P are moved relative to each other while discharging the droplets 32 from the nozzles 19 of the recording unit 14. It is possible to form dots 34 by the droplets 32 or to stack the dots 34 thereon. The support P may be planar or may be a three-dimensional shape with irregularities.

(Image formation method)
A printing method (also referred to as an image forming method) by the image forming apparatus 30 will be described. The image forming apparatus 30 according to the present embodiment can perform image formation by a multi-scan method under the control of the scan control unit 28A. Further, the image forming apparatus 30 can perform image formation by a mat stacking method, which will be described later, under the control of the mat stacking control unit 28C. Further, it is preferable that image formation by a mat lamination method, which will be described later, can be performed under the control of the normal lamination control unit 28B. Each image forming method will be described below.

[Multi-scan method]
First, the multi-scan method will be described. As an image forming method of an ink jet image forming apparatus, an image is formed by performing multiple times of main scanning (scanning) with the same or different nozzle groups on the same region (image forming region) of the support P. Multi-scan printing (multi-pass printing) is known. By performing main scanning a plurality of times on the same region of the support P, it is possible to form an image with high resolution. Hereinafter, printing with n main scans on the same region of the support P is referred to as n-scan printing.

  Further, in multi-scan printing, a mask process for equally distributing the nozzles 19 for the number of scans is performed. 7 and 8 are schematic views of the head 18 having 12 nozzles. Note that the number of nozzles is generally 1000 nozzles or more, such as 1280 nozzles, but here, an example of 12 nozzles will be described to simplify the description.

  As shown in FIG. 7, when an image is formed by two-scan printing using a head 18 having twelve nozzles 19, six nozzles are used in one scan because the number of nozzles is 12 / the number of scans is 2 = 6. Will be used. Therefore, for example, in the first scan, mask processing is performed so that an image is formed using the six nozzles 19 of the nozzle group 20a and in the second scan, the six nozzles 19 of the nozzle group 20b.

  If the number of nozzles is not divisible by the number of scans, an unused nozzle may be provided and a divisible number of nozzles may be used. At this time, the number of unused nozzles is set to a minimum number. Therefore, for example, as shown in FIG. 8, when an image is formed by 5-scan printing using a head 18 having 12 nozzles 19, the number of nozzles is 12 / the number of scans is 5 = 2. In this scan, two nozzles are used, and the two nozzles become unused nozzles 19n. For example, in the first scan, the two nozzles 19 in the nozzle group 20a, in the second scan, the two nozzles 19 in the nozzle group 20b, in the third scan, the two nozzles 19 in the nozzle group 20c, in the fourth scan, the nozzles In the second nozzle 19 and the fifth scan of the group 20d, an image is formed using the two nozzles 19 of the nozzle group 20e.

  FIGS. 9A to 9E are explanatory views showing the state of image formation by two-scan printing, showing the recording unit 14 and the support P from above in the vertical direction Z. FIG. As shown in FIG. 9A, in the first scan, the recording unit 14 moves relative to the support P in the main scanning direction X. Then, an image 17a1 is formed on the support P as shown in FIG. This image 17a1 is a state in which one scan is completed among the images formed by two scans.

  Next, as shown in FIG. 9C, the recording unit 14 returns to the original position in the main scanning direction X relative to the support P and moves in the sub-scanning direction Y. Then, as shown in FIG. 9D, the second scan image 17a2 is formed in the left region, and the first scan image 17b1 is formed in the right region. When the image 17a2 is formed, the image formation in this area is completed. The image 17b1 is a state in which one scan is completed among images formed by two scans. The image 17b1 is formed by the nozzle group of the first scan on which the image 17a1 is formed.

  Next, as shown in FIG. 9E, the recording unit 14 returns to the original position in the main scanning direction X relative to the support P, and moves in the sub-scanning direction Y to perform two scans in the right region. The image of the eye image 17b2 is formed. When the image 17b2 is formed, the image formation in this area is completed, and the formation of the image 17 is completed.

  In the two-scan printing shown in FIG. 9, the images 17a1 and 17b1 are images formed by the nozzle group assigned to the first scan, and the images 17a2 and 17b2 are formed by the nozzle group assigned to the second scan. It becomes an image.

  In the example of FIG. 9, to simplify the description, an example of multi-scan printing in which an image formed in the first scan and an image formed in the second scan are superimposed to form one image is shown. However, in the multi-scan printing and the normal stacking method and the mat stacking method described below, the dots 34 land on the small regions that are subdivided in the same region for each scan, thereby causing the image 17. Needless to say, the one formed by is included.

[Normal lamination method]
The image forming apparatus 30 according to the present embodiment is preferably capable of image formation by the normal stacking method under the control of the normal stacking control unit 28B. The normal lamination method is a method of forming an image by repeating the multi-scan printing described so far for a predetermined number of layers (for example, three layers).

  A normal lamination method in which each layer is formed by 16-scan printing will be described with reference to FIG. FIG. 10A is a schematic diagram of the head 18 in which a mask is set for the first to sixteenth scans for 16-scan printing. The nozzle group 20a is formed in the first scan, the nozzle group 20b is formed in the second scan,..., And the nozzle group 20p is formed in the sixteenth scan.

  In the normal lamination method, as shown in FIG. 10B, the image 17a1 is formed by the nozzle group 20a in the first scan. Next, as shown in FIG. 10C, movement in the sub-scanning direction Y (hereinafter also referred to as line feed) is performed, and in the second scan, an image 17a2 is formed by the nozzle group 20b, and an image 17b1 ( 1st scan) is formed.

  When the 16th scan is reached, an image 17a16 is formed by the nozzle group 20p as shown in FIG. 10D, and the image formation in this region is completed. At this time, an image 17p1 (first scan) is formed, and when the sixteenth scan is completed in this region, the image is completed.

  With the series of operations shown in FIGS. 10B to 10D, a one-layer image is formed. That is, when three layers are printed by the normal lamination method, after the formation of the first layer image, the state again returns to the state of FIG. 10B, and the second layer image is formed on the already formed first layer image. I will do it.

That is, the image forming operation of the normal lamination method is
(1st scan → line feed → 2nd scan → line feed →... → 16 scans) × number of stacked layers.

  FIG. 11 is an image diagram showing how dots 34 are stacked by droplets 32 ejected in the first to sixteenth scans when three layers are printed by the normal stacking method.

  As shown in FIG. 11, in the normal stacking method, the dots 34 land on the 1st to 16th scans as indicated by the encircled numbers 1 to 16 in the figure to form the first layer. Next, dots 34 with circled numbers 1 to 16 in the figure land and form the second layer, then dots 34 with circled numbers 1 to 16 in the figure land and form the third layer Is done.

  FIG. 12 is an example of an enlarged image diagram showing a state of dot 34 lamination in the normal lamination method. The image forming apparatus 30 often prints with a dot diameter larger than the distance between adjacent dots. For this reason, in the case of the normal lamination method, as shown in FIG. 12, for example, a portion (overlapping portion O) where the dot 34 landed in the second scan overlaps on the dot 34 landed in the first scan occurs.

  According to this normal lamination method, as shown in Patent Document 2, for each layer, it is possible to form an image with excellent gloss uniformity by controlling the amounts of color ink and clear ink. However, there is a limit to keeping the gloss level low. This is due to the fact that the surface of the image cannot be roughened as shown in FIGS.

[Matte lamination method]
Therefore, the image forming apparatus 30 according to the present embodiment performs image formation by the mat lamination method under the control of the mat lamination control unit 28C.

  A mat lamination method in which each layer is formed by 16 scan printing will be described with reference to FIG. Here, three-layer printing will be described. In the case of the mat lamination method, unlike the normal lamination method, the layers are not sequentially formed as in the first layer, the second layer,... This will be described using the concept of the number of layers in the system.

  FIG. 13A is a schematic diagram of the head 18 in which a mask is set for the first to sixteenth scans for 16-scan printing. An image is formed using the nozzle group 20a in the first scan, the nozzle group 20b in the second scan,..., And the nozzle group 20p in the 16th scan, which is the same as that shown in FIG. .

  In the mat lamination method, as shown in FIG. 13B, the image 17a1 (1) is formed by the nozzle group 20a in the first scan. (N) indicates an image in the nth layer.

  Next, as shown in FIG. 13C, line feed is not performed, the second main scan (second scan) is performed as it is, and an image 17a1 (2) is formed by the nozzle group 20a.

  Next, as shown in FIG. 13D, line feed is not performed, the third main scan (third scan) is performed as it is, and an image 17a1 (3) is formed by the nozzle group 20a.

  Next, as shown in FIG. 13E, a line feed is made, and in the second scan, an image 17a2 (1) is formed by the nozzle group 20b. At this time, the image 17b1 (1) is formed by the nozzle group 20a in the region where the images 17a1 (1) to (3) are formed. Thereafter, the image is completed up to the 16th scan.

That is, the image forming operation of the mat lamination method is
First scan × number of stacks → second scan × number of stacks ... → 16 scans × number of stacks. In the mat lamination method, an image is not formed for each layer, but images for a plurality of layers are formed in a three-dimensional manner. In the case of one layer, the mat lamination method and the normal lamination method image formation are performed in exactly the same procedure, so the mat lamination method is applied to the case of two or more layers.

  FIG. 14 is an image diagram showing a state in which dots 34 are stacked by droplets 32 ejected in the first to sixteenth scans when three layers are printed by the mat stacking method.

  As shown in FIG. 14, in the mat lamination method, dots 34 ((1) to (3) of circled numbers 1) of each layer (1) to (3) for the first scan, and then each layer ( Dots 34 (1) to (3) (circled numeral 2 (1) to (3)) and dots 34 (circled numeral 3 (1) to (3) of each layer (1) to (3) for the third scan) 3)),..., And dots 34 (circled numeral 16 (1) to (3)) of each layer (1) to (3) are formed for the 16th scan.

  FIG. 15 is an example of an enlarged image diagram showing a state of dot 34 lamination in the mat lamination method. As described above, the image forming apparatus 30 often prints with a dot diameter larger than the distance between adjacent dots.

  Also in this case, as shown in FIG. 15A, the dots 34 (circled numeral 1 (1) to (3)) of the respective layers (1) to (3) are stacked and formed for the first scan. As shown in FIGS. 15B and 15C, when printing is performed at a position adjacent to the stacked dots 34 (the layers (1) to (3) in the fourth scan), the ink is lowered by gravity. drop down. Therefore, as shown in FIG. 15D, the ink G does not overlap the stacked dots 34, and the groove G between the adjacent dots can be deepened. The mat lamination method increases the proportion of the groove G and diffuses and reflects light, so that image formation with reduced glossiness is possible.

(Glossiness by image forming method)
The image forming apparatus 30 is capable of image formation of both an image forming method using a mat stacking method and an image forming method using a normal stacking method. It is preferable that either the method or the mat lamination method is selected and executed. For example, in a mode in which the gloss level is equal to or less than a predetermined value (low gloss mode), the mat lamination method is selected, and in the other modes, the normal printing method is selected.

  FIG. 16 is a flowchart illustrating an example of image forming method selection processing. First, the data receiving unit 12A of the main control unit 13 receives image data (S101). Next, the gloss level for printing the image data received by the data receiving unit 12A is designated by the user (S102). The gloss level designation process is not particularly limited. For example, a selection screen that allows the user to select the gloss level is displayed on the display unit 131 of the image processing apparatus 12, and input from the user input unit 130 is performed. Anything can be accepted. In the glossiness designation process (S102), before the data receiving unit 12A receives the image data, the glossiness data is added to the image data, and the image data including the glossiness information is received. You may send to the part 12A.

  Next, the determination unit 12D sets the image forming method to the mat lamination method or the normal lamination method based on the glossiness selected in the glossiness designation process (S102) and a predetermined value (threshold value) set in advance. (S103).

  When the selected gloss level is equal to or less than the predetermined value (S103: Yes), the determination unit 12D selects printing using the mat lamination method (S104). On the other hand, when the selected glossiness exceeds a predetermined value (S103: No), it is selected to print by the normal lamination method (S107).

  Next, the data creation unit 12B performs image processing on the image data based on the selected printing method (S105, S108). In the case of the mat lamination method, the data creation unit 12B rearranges the image data so that the liquid droplets 32 are ejected from the nozzles 19 in the ejection order of the mat lamination method described above. Image data for ejecting the droplets 32 from the nozzles 19 is created in the order of ejection in the stacked system.

  Next, the data output unit 12 </ b> C outputs the image data subjected to image processing by the data creation unit 12 </ b> B to the image forming apparatus 30. Further, the recording control unit 28 controls the recording unit 14, the driving unit 25, and the irradiation unit 22 of the image forming apparatus 30 according to the selected method (S 106, S 109).

  FIG. 17 is a flowchart showing details of the printing process (S106 in FIG. 16) by the mat lamination method.

  The mat lamination control unit 28C causes the recording unit 14 to eject the droplet 32 at a predetermined position, and causes the irradiation unit 22 to irradiate the ejected droplet 32 (dot 34) to cure it (S201).

  The mat lamination control unit 28C confirms whether n layers are stacked and printed at a predetermined position after the dots 34 are cured (S202). When the predetermined number of layers (n layers) are not overprinted (S202: No), the process returns to S201. On the other hand, when n layers are overlaid (S202: Yes), the mat lamination control unit 28C determines whether printing is completed (S203).

  When there is no image data to be printed (S203: Yes), the mat lamination control unit 28C ends printing. On the other hand, when there is image data to be printed (S203: No), the mat stack control unit 28C controls the recording unit 14 or the operation stage 16 to relatively move in the sub-scanning direction (S204). After moving in the sub-scanning direction, the process returns to S201, and printing is started again by the recording unit 14.

  FIG. 18 is a flowchart showing details of the printing process (S109 in FIG. 16) by the normal lamination method.

  The normal stacking control unit 28B causes the recording unit 14 to eject the droplet 32 at a predetermined position, and causes the irradiation unit 22 to irradiate the ejected droplet 32 (dot 34) to cure it (S301).

  The normal stacking control unit 28B confirms whether a single-layer image is formed after the dots 34 are cured (S302). When the image of one layer is not formed (S302: No), the normal stacking control unit 28B controls the recording unit 14 or the operation stage 16 to relatively move in the sub-scanning direction (S303). After the recording unit 14 or the operation stage 16 is relatively moved in the sub-scanning direction, the process returns to S301.

  When an image of one layer is formed (S302: Yes), the normal stack control unit 28B determines whether or not printing of a plurality of layers is completed (S304). When printing of a plurality of layers is completed (S304: Yes), normal laminated printing is completed.

  When printing of a plurality of layers has not been completed (S304: No), the normal stacking control unit 28B controls the recording unit 14 or the operation stage 16 to relatively move in the sub-scanning direction (S305). At this time, the normal stacking control unit 28B moves the recording unit 14 or the operation stage 16 to the image formation start position. After moving the recording unit 14 or the operation stage 16, the process returns to S301.

  FIG. 19 is a graph showing the relationship between the number of layers and the 60-degree glossiness for each lamination method. As described above, in the case of a single layer, the image formation in the mat lamination method and the normal lamination method have exactly the same procedure, and therefore have the same value as illustrated.

  And as shown in FIG. 19, when it is set as two or more layers, according to the mat | stacking system, it turns out that 60 degree glossiness can be suppressed to a low value. In the measurement example of FIG. 19, it can be seen that the normal lamination method is 8 or less for two layers and 7 or less for three layers, whereas the mat lamination method can be 4 or less for two layers and 3 or less for three layers.

  FIG. 20 is a graph showing the relationship between the number of layers and the arithmetic average roughness Ra for each lamination method. In the case of a single layer, the same value is obtained as shown for the above reason.

  As shown in FIG. 20, when the number of layers is two or more, the arithmetic average roughness Ra increases as the number of layers increases in the mat lamination method. Since the glossiness is in a trade-off relationship with the arithmetic average roughness Ra, it can be seen from the graph shown in FIG. 20 that the glossiness can be suppressed to a low value according to the mat lamination method.

  Thus, it can be seen that the image formed by the mat lamination method has a roughened surface portion by deepening the groove between the adjacent dots than the image formed by the normal lamination method. Thereby, it is possible to form an image with low glossiness.

  Further, when forming an image composed of three or more layers, an image is formed by the mat lamination method for a predetermined number of layers from the uppermost layer among the plurality of layers, and an image is formed by the normal lamination method for the remaining layers. Even in this case, it is possible to form an image with a low glossiness by roughening the surface portion.

  In the description so far, the example in which the image data rearrangement process is performed in order to change the dot order is described. However, in the case of a solid image, the mat lamination method is used without rearranging the image data. An image can be formed.

(Gloss uniformity control)
Hereinafter, a description will be given of performing image formation with a glossiness desired by the user by combining image formation by the mat lamination method and image formation by the normal lamination method.

  The image processing apparatus 12 according to the present embodiment preferably includes a patch forming unit 28D. The patch forming unit 28D prints a test chart on which a plurality of patches are formed while changing the number of layers and the combination of the normal stacking method and the mat stacking method.

  FIG. 21 shows a stack type test chart. FIG. 22 is an explanatory diagram showing how the patches indicated by the circled numerals 1 to 15 in FIG. 21 are formed by combining image formation by the mat lamination method and image formation by the normal lamination method. .

  The test chart shown in FIG. 21 is a patch in which images of 1 to 5 layers are formed using only black ink droplets, and each layer is formed by a combination of the image forming methods shown in FIG. It is. In FIG. 21, although the density appears to be different, each patch is a solid image printed using only black ink droplets, and is actually a patch having the same gradation value but different number of layers and glossiness. .

  It is possible to measure the glossiness of each patch for each patch shown in FIG. 21 and select a combination of image forming methods according to the glossiness desired by the user.

  By forming the test chart shown in FIG. 21 for each ink color, it is possible to measure the glossiness of each ink color by combining image lamination methods when forming a multi-layer image. A relationship can be sought. Therefore, an image can be formed by selecting an optimal combination of the number of layers and the image forming method in accordance with the glossiness desired by the user.

  FIG. 23 shows a grayscale chart for black ink droplets. The patch forming unit 28D prints a gray scale chart in which a plurality of patches formed while changing the amount of color ink (color duty) and the amount of clear ink (clear duty) discharged per unit volume are formed. Here, an example is shown in which black ink droplets and clear ink are used. The reference for determining the color duty and clear duty at this time is the amount of each ink per unit volume in a plurality of layers.

  The gray scale chart shown in FIG. 23 is output using a predetermined number of stacks and combinations of the stack methods selected from the test chart of FIG. 21, and the glossiness of each patch is measured using each patch of the gray scale chart. Then, a combination of the color duty and the clear duty that achieves the user-desired glossiness can be selected so that the user-desired glossiness is obtained.

  FIG. 24 is a schematic diagram when three-layer printing is performed using clear ink. The dots 34k are dots of black ink droplets, and the dots 34t are dots of ink droplets of clear ink. As shown in FIG. 24, by laminating the color ink on the outermost layer and the clear ink on the lower layer portion, for example, a low density region can be formed as shown by L in the figure, A uniform surface shape can be obtained regardless of the concentration.

  In this way, it is possible to adjust the glossiness of the entire image by further ejecting a predetermined amount of clear ink in addition to the color ink for each area (portion) of the image, thereby forming an image with high gloss uniformity. Become.

  According to the present embodiment described above, in an image forming apparatus that discharges ink that is cured by light irradiation and cures the ink by light irradiation to form an image on an image forming object, by stacking dots. By adopting a printing method (matte lamination method) for roughening the printing surface, the glossiness can be suppressed to a low value of a predetermined value or less (for example, 60 ° glossiness is 7 or less).

  Further, by adjusting the duty of the color ink and the clear ink, it is possible to form an image with excellent gloss uniformity while suppressing the glossiness to a low value below a predetermined value.

  The above-described embodiment is a preferred embodiment of the present invention, but is not limited thereto, and various modifications can be made without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 10 Image processing system 12 Image processing apparatus 12A Data reception part 12B Data preparation part 12C Data output part 12D Judgment part 13 Main control part 14 Recording part 16 Operation | movement stage 17 Image 18 Head 19 Nozzle 20 Nozzle group 22 Irradiation part 23 1st drive part 24 second drive unit 25 drive unit 28 recording control unit 28A scan control unit 28B normal stacking control unit 28C mat stacking control unit 28D patch forming unit 30 image forming apparatus 32 droplet 34 dot

JP 2000-318140 A JP 2012-254613 A

Claims (10)

An image forming apparatus for forming an image on an image forming object,
A recording unit that ejects liquid that hardens upon stimulation;
A curing unit that cures the liquid ejected by the recording unit;
A drive unit for moving the recording unit;
In one image forming area where an image is formed, the recording unit and the curing unit are moved in the sub-scanning direction relative to the image forming object, and the recording unit is moved with respect to the image forming object. A scanning control unit that controls the driving unit so as to scan a plurality of times relatively in the main scanning direction;
When forming an image formed by the scan control unit as one layer and forming a plurality of layers, after forming an image by scanning the number of layers in one main image forming region in the main scanning direction, the recording unit A mat stack control unit that moves the image forming object relative to the image forming object in the sub-scanning direction to perform image formation for the next number of scans;
An image forming apparatus comprising:   Normally, when an image formed by the scan control unit is a single layer and an image composed of a plurality of layers is formed, the image is formed by sequentially performing the image forming operation of one layer by the scan control unit for the number of layers. The image forming apparatus according to claim 1, further comprising a stacking control unit.   When forming a multi-layer image, when the low gloss mode is set, the mat stack control unit forms an image, and when setting another mode, the normal stack control unit sets the image. The image forming apparatus according to claim 2, wherein an image is formed.   When forming an image consisting of a plurality of layers, an image is formed by the mat lamination control unit for a predetermined number of layers from the uppermost layer, and an image is formed by the normal lamination control unit for the remaining layers. The image forming apparatus according to claim 2.   For each color of the liquid, multiple types of patches are formed while changing the number of layers by combining one or more image formations by the normal lamination control unit and / or two or more layer image formations by the mat lamination control unit. The image forming apparatus according to claim 2, further comprising a patch forming unit that performs the operation. The liquid includes clear ink;
The patch forming unit is a color duty that is the amount of color ink ejected per unit volume and a clear ink amount that is ejected per unit volume for a combination of a predetermined number of layers and a predetermined image forming method. The image forming apparatus according to claim 5, wherein a plurality of types of patches are formed while changing the clear duty.   The image forming apparatus according to claim 1, wherein an image having three layers is formed.   8. The scan control unit according to claim 1, wherein a value obtained by dividing the number of nozzles provided in the recording unit by the number of scans in the main scanning direction is used as the number of nozzles used in one scan. An image forming apparatus according to claim 1.   9. The image forming apparatus according to claim 8, wherein the scan control unit sets the number of nozzles corresponding to the remainder when the number of nozzles included in the recording unit is divided by the number of scans in the main scanning direction as unused nozzles. apparatus. An image forming operation for discharging the liquid that is cured by stimulation is performed and the liquid is cured, and a recording unit that discharges the liquid is scanned in the main scanning direction in all image forming regions, and then an image is formed in the sub-scanning direction. When an image formed by repeating an image forming operation to be scanned is a single layer, a method for producing an output product that forms an image of a plurality of layers on an image forming product,
Moving the recording unit in the main scanning direction relative to the image forming object in one image forming region where an image is formed, and discharging and curing the liquid by the number of layers;
Scanning the number of layers to form an image, and then moving the recording unit in the sub-scanning direction relative to the image forming object to form an image for the next number of scans;
A method of producing an output product characterized by