Image forming apparatus, image forming method, and image forming program

Abstract

To provide an image formation apparatus which can express a high-gloss image in a hue like a metallic color.SOLUTION: An image formation apparatus according to an aspect of the present invention comprises: a liquid discharge head which discharges liquid onto a recording medium; an irradiation unit which irradiates the liquid on the recording medium with light; a carriage which is provided with the liquid discharge head and the irradiation unit; and a movement unit which performs a main scanning movement that relatively moves the carriage in the main-scanning direction with respect to the recording medium and a sub-scanning movement that relatively moves the carriage in the sub-scanning direction orthogonal to the main-scanning direction with respect to the recording medium. The liquid contains metallic ink and color ink. The liquid discharge head discharges the color ink to a region where the metallic ink is discharged to the recording medium in the main-scanning movement in the same main-scanning movement. The irradiation unit irradiates the region to which the metallic ink and the color ink are discharged with the light in the same main-scanning movement.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an image forming apparatus, an image forming method, and an image forming program. [Background technology]

[0002] Conventionally, there has been known an image forming device that ejects liquid onto a recording medium while moving the recording medium and a liquid ejection head, which has multiple nozzles arranged as a nozzle row in the sub-scanning direction, relative to each other in both the main scanning direction and the sub-scanning direction perpendicular to the main scanning direction, to form an image on the recording medium.

[0003] Furthermore, a printing method has been disclosed in which, when forming an image by ejecting metallic ink containing ultraviolet-curable metal particles, a leveling process, a pre-curing process, and a main curing process are carried out to improve the brightness of the image (see, for example, Patent Document 1). Summary of the Invention [Problem to be solved by the invention]

[0004] However, the printing method of Patent Document 1 only discloses image formation using metallic ink, and is unable to produce images with high gloss and color such as metallic colors, which are produced by overlapping metallic ink and color ink in a certain area.

[0005] SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming apparatus capable of expressing colorful, high-gloss images such as metallic colors. [Means for solving the problem]

[0006] An image forming apparatus according to one aspect of the present invention includes a liquid ejection head that ejects liquid onto a recording medium, an irradiation unit that irradiates the liquid on the recording medium with light, a carriage provided with the liquid ejection head and the irradiation unit, and a movement unit that performs main scanning movement to move the carriage relatively to the recording medium in a main scanning direction and sub-scanning movement to move the carriage relatively to the recording medium in a sub-scanning direction perpendicular to the main scanning direction, wherein the liquid includes metallic ink and color ink, and the liquid ejection head ejects the color ink onto an area onto which the metallic ink was ejected during the main scanning movement on the recording medium, and the irradiation unit irradiates the light onto the area onto which the metallic ink and the color ink were ejected during the same main scanning movement. the main scanning movement includes movement in both directions, the liquid ejection head includes a metallic ink ejection head that ejects the metallic ink and a color ink ejection head that ejects the color ink; the irradiation unit includes a plurality of irradiation units; and the carriage is provided with the color ink ejection heads and the irradiation units in this order from the side closest to the metallic ink ejection head on both sides of the metallic ink ejection head. . [Effects of the Invention]

[0007] According to the present invention, it is possible to produce a high-gloss image with metallic colors and other colors. [Brief explanation of the drawings]

[0008] [Figure 1] 1A and 1B are diagrams showing an example of the overall configuration of an image forming apparatus according to a first embodiment, in which FIG. 1A is a perspective view seen from the front side of the apparatus, and FIG. 1B is a perspective view seen from the rear side of the apparatus. [Figure 2] 2A and 2B are diagrams illustrating an example of the configuration of a carriage according to the first embodiment. [Figure 3] FIG. 2 is a diagram illustrating an example of the hardware configuration of the image forming apparatus according to the first embodiment. [Figure 4] FIG. 2 is a diagram illustrating an example of the functional configuration of a controller unit according to the first embodiment. [Figure 5] 4 is a flowchart of an example of the operation of the image forming apparatus according to the first embodiment. [Figure 6] 6A to 6D are diagrams showing how an image is formed on a sheet, and are diagrams showing examples of image formation in the first to fourth main scanning movements. [Figure 7]FIG. 10 is a perspective view of another example of the overall configuration of the image forming apparatus according to the embodiment. [Figure 8] FIG. 10 is a diagram illustrating an example of the configuration of a carriage according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following describes the preferred embodiments of the present invention with reference to the accompanying drawings. In the drawings, the same components are designated by the same reference numerals, and redundant explanations may be omitted.

[0010] Furthermore, the embodiments shown below are examples of image forming apparatuses that embody the technical concepts of the present invention, and the present invention is not limited to the embodiments shown below. The dimensions, materials, shapes, relative locations, etc. of the components described below are intended to be illustrative and not to limit the scope of the present invention unless otherwise specified. Furthermore, the sizes and positional relationships of components shown in the drawings may be exaggerated for clarity.

[0011] The image forming apparatus according to the embodiment comprises a liquid ejection head that ejects liquid onto a recording medium, an irradiation unit that irradiates light onto the liquid on the recording medium, a carriage equipped with the liquid ejection head and the irradiation unit, and a moving unit that performs main scanning movement to move the carriage relative to the recording medium in the main scanning direction, and sub-scanning movement to move the carriage relative to the recording medium in a sub-scanning direction perpendicular to the main scanning direction.

[0012] The liquid includes metallic ink and color ink. The metallic ink and color ink are, for example, ultraviolet curable, and the irradiation unit cures the liquid by irradiating it with ultraviolet light.

[0013] In an embodiment, the liquid ejection head ejects color ink onto an area onto which metallic ink has been ejected during a main scanning movement on the recording medium, and the irradiation unit irradiates the area with light during the same main scanning movement. This ensures a long time between the ejection of the metallic ink and the start of curing, enabling the expression of colorful, high-gloss images such as metallic colors.

[0014] Here, metallic refers to something that has a metallic luster.

[0015] Hereinafter, an embodiment will be described using an inkjet image forming apparatus as an example, which forms an image by ejecting ultraviolet-curable ink onto paper. Here, ink is an example of a liquid, and paper is an example of a recording medium. Paper includes various types of paper, such as plain paper and glossy paper. However, the recording medium is not limited to paper, and may be a plastic film, prepreg, silver foil, or the like.

[0016] Furthermore, the terms "image formation," "recording," "printing," "imaging," and "printing" used in the embodiments are all synonymous. Furthermore, the liquid is not particularly limited as long as it has a viscosity and surface tension that allows it to be ejected from a liquid ejection head, but it is preferable that the viscosity of the liquid be 30 mPa s or less at room temperature and normal pressure, or upon heating or cooling.

[0017] More specifically, these include solutions, suspensions, emulsions, and the like containing solvents such as water and organic solvents, colorants such as dyes and pigments, polymerizable compounds, resins, surfactants, and other functionality-imparting materials, biocompatible materials such as DNA, amino acids, proteins, and calcium, edible materials such as natural dyes, and the like, and these can be used for applications such as inkjet inks, surface treatment liquids, liquids for forming components of electronic elements and light-emitting elements, and electronic circuit resist patterns, and material liquids for three-dimensional modeling.

[0018] A liquid ejection head is a functional component that ejects and sprays liquid from a nozzle. Examples of liquid ejection heads include those that use piezoelectric actuators (laminated piezoelectric elements and thin-film piezoelectric elements), thermal actuators that use electrothermal conversion elements such as heating resistors, and electrostatic actuators that consist of a vibration plate and an opposing electrode as energy sources for ejecting liquid.

[0019] In the following description, the main scanning direction is referred to as the X-axis direction, the sub-scanning direction that is approximately perpendicular to the main scanning direction is referred to as the Y-axis direction, and the direction that is perpendicular to both the X-axis direction and the Y-axis direction is referred to as the Z-axis direction. Note that the direction in which the arrow points on the X-axis direction is referred to as the +X direction, and the direction opposite to the +X direction is referred to as the -X direction, the direction in which the arrow points on the Y-axis direction is referred to as the +Y direction, and the direction opposite to the +Y direction is referred to as the -Y direction, and the direction in which the arrow points on the Z-axis direction is referred to as the +Z direction, and the direction opposite to the +Z direction is referred to as the -Z direction. However, these do not limit the orientation of the image forming device, and the orientation of the image forming device is arbitrary.

[0020] [First embodiment] (Example of overall configuration of image forming apparatus 10) First, the overall configuration of an image forming apparatus 10 according to an embodiment will be described. Fig. 1 is a perspective view showing an example of the overall configuration of the image forming apparatus 10. Fig. 1(a) is a perspective view seen from the front side of the apparatus, and Fig. 1(b) is a perspective view seen from the rear side of the apparatus.

[0021] The image forming apparatus 10 includes a carriage 200 and a mounting table 13 on which a paper sheet P is placed. The carriage 200 is provided with an ink ejection head and an irradiation unit. The ink ejection head is an example of a liquid ejection head in which a plurality of nozzles that eject ink onto the paper sheet P are arranged as a nozzle row in the sub-scanning direction.

[0022] The ink ejection head forms an image by ejecting ink from its nozzles. The nozzles are provided to face the mounting table 13. An irradiation unit is also provided to face the mounting table 13. The ink ejection head and irradiation unit will be described in detail later with reference to FIG. 2.

[0023] A guide rod 19 is hung between the left and right side plates 18a, 18b, and the guide rod 19 holds a carriage 200 so that the carriage 200 can move in the X-axis direction. The carriage 200 performs main scanning movement along the guide rod 19, moving relative to the paper P in the main scanning direction.

[0024] The carriage 200, guide rod 19, and side plates 18a and 18b are integrally movable in the Y-axis direction along guide rails 29 provided at the bottom of the mounting table 13. The carriage 200 performs sub-scanning movement along the guide rails 29, moving relative to the recording medium in the sub-scanning direction.

[0025] Furthermore, the carriage 200 is held so as to be movable in the Z direction (up and down direction).

[0026] The image forming apparatus 10 is capable of so-called bidirectional printing, in which images are formed on both the forward path, which is a main scanning movement along the +X direction, and the backward path, which is a main scanning movement along the -X direction.

[0027] (Example of the carriage 200 configuration) Next, the configuration of the carriage 200 will be described with reference to Fig. 2. Fig. 2 is a diagram showing an example of the configuration of the carriage. Fig. 2 is a diagram showing the carriage 200 in Fig. 1 as viewed from the -Z direction side.

[0028] The carriage 200 is a box-shaped member that is open on the -Z direction side. As shown in Figure 2, the carriage 200 is equipped with a metallic ink ejection head 300, color ink ejection heads 301a, 301b, 301c, and 301d, and irradiation units 400a and 400b inside the box-shaped member.

[0029] The color ink ejection heads 301a, 301b, 301c, and 301d have the same configuration except for the color of ink they eject and their positions, and therefore, hereinafter, unless otherwise distinguished, they will be collectively referred to as color ink ejection head 301. Furthermore, the irradiation units 400a and 400b have the same configuration except for their positions, and therefore, hereinafter, unless otherwise distinguished, they will be collectively referred to as irradiation unit 400.

[0030] The metallic ink ejection head 300 and the color ink ejection head 301 have the same configuration except for the type of ink they eject and their positions, but they do not necessarily have to have the same configuration.

[0031] The carriage 200 holds the metallic ink ejection head 300, the color ink ejection head 301, and the irradiation unit 400 so that they face the paper P placed on the −Z direction side of the carriage 200.

[0032] The metallic ink ejection head 300 has a piezoelectric element as a pressure generating unit, and contracts in response to a drive signal. The pressure change caused by the contraction causes metallic ink to be ejected in the −Z direction through each nozzle included in the nozzle row 300n.

[0033] The metallic ink according to the embodiment is an ultraviolet-curable ink containing at least a monomer or oligomer, a photopolymerization initiator, and metallic particles. For example, an ink containing a methacrylate-based monomer can be used as the ultraviolet-curable ink. Methacrylate-based monomers have the characteristics of being relatively sensitive to the skin and undergoing a large degree of shrinkage upon curing.

[0034] The ultraviolet curable ink may further contain additives, such as a sensitizer, a dispersant, a leveling agent, and a polymerization inhibitor, which can be selected as appropriate.

[0035] In the embodiment, the metallic particles are aluminum particles having an outer diameter of about 5 μm and a thickness of about 0.1 μm to 0.2 μm, and are flaky or flat particles. However, the present invention is not limited to this, and metal particles other than aluminum can be used, and the shape does not have to be flaky.

[0036] The color ink ejection head 301 has a piezoelectric element as a pressure generating unit, and contracts in response to a drive signal. The pressure change caused by the contraction causes color ink to be ejected in the −Z direction through each nozzle included in the nozzle row 301n.

[0037] The color ink according to the embodiment is an ultraviolet-curable ink containing at least a monomer or oligomer, a photopolymerization initiator, and colored particles. The colored particles are particles of dyes or pigments. The colors of the colored particles are, for example, cyan, magenta, yellow, and black, but are not limited thereto, and can be selected appropriately depending on the application of the image forming apparatus 10.

[0038] The materials constituting the ultraviolet curable ink are not particularly limited to those mentioned above, and various materials can be used as appropriate depending on the application of the image forming apparatus 10. The same applies to the viscosity and surface tension of the ink.

[0039] It is preferable that at least one of the metallic ink and the color ink contains a solvent, as this increases volatility and improves curing efficiency or drying efficiency, and it is also preferable that at least one of the metallic ink and the color ink contains water, as this improves environmental resistance.

[0040] The irradiation unit 400 is an example of an irradiation section that irradiates light onto the metallic ink and color ink on the paper P. The irradiation units 400a and 400b are an example of a plurality of irradiation sections.

[0041] In this embodiment, the irradiation unit 400 irradiates ultraviolet light to cure the metallic ink and color ink on the paper P. The cured metallic ink and color ink adhere to and are fixed on the paper P. For example, a UV (Ultra Violet) lamp can be used as the irradiation unit 400.

[0042] The length of the irradiation unit 400 in the sub-scanning direction is preferably longer than the lengths in the sub-scanning direction of the metallic ink ejection head 300 and the color ink ejection head 301. This allows the metallic ink ejection head 300 or the color ink ejection head 301 to irradiate the entire ink in the sub-scanning direction ejected onto the paper P in one main scanning movement with ultraviolet light.

[0043] As shown in FIG. 2, the carriage 200 is provided with a metallic ink ejection head 300, a color ink ejection head 301, and an irradiation unit 400 aligned in the main scanning direction.

[0044] On the carriage 200, on both sides of the metallic ink ejection head 300, a color ink ejection head 301 and an irradiation unit 400 are provided in this order from the side closest to the metallic ink ejection head 300.

[0045] Specifically, a color ink ejection head 301a, a color ink ejection head 301b, and an irradiation unit 400a are arranged in this order from downstream to upstream on the outgoing path of the main scanning movement on the -X direction side of the metallic ink ejection head 300. Furthermore, a color ink ejection head 301c, a color ink ejection head 301d, and an irradiation unit 400b are arranged in this order from downstream to upstream on the return path of the main scanning movement on the +X direction side of the metallic ink ejection head 300.

[0046] (Example of hardware configuration of image forming apparatus 10) Next, the hardware configuration of the image forming apparatus 10 will be described with reference to Fig. 3. Fig. 3 is a block diagram showing an example of the hardware configuration of the image forming apparatus 10.

[0047] As shown in FIG. 3, the image forming apparatus 10 includes a controller unit 3, a detection group 4, a transport unit 100, a carriage 200, a metallic ink ejection head 300, a color ink ejection head 301, an irradiation unit 400, and a maintenance unit 500.

[0048] Of these, the controller unit 3 includes a unit control circuit 31, a memory 32, a CPU (Central Processing Unit) 33, and an I / F (Interface) .

[0049] The I / F 34 is an interface for connecting the image forming apparatus 10 to an external device, such as a PC (Personal Computer) 2. The image forming apparatus 10 and the PC 26 may be connected in any manner, such as via a network or by directly connecting the two via a communication cable.

[0050] The CPU 33 uses the memory 32 as a working area and controls each unit of the image forming apparatus 10 via the unit control circuit 31. Specifically, the CPU 33 controls each unit based on image data received from the PC 26 and data detected by the detection group 4, and forms an image on the paper P.

[0051] The detection group 4 includes various sensors provided in the image forming apparatus 10, such as an encoder sensor that detects the position of the carriage 200 in the main scanning direction.

[0052] A printer driver is installed in PC 26. The printer driver generates image data to be sent to image forming apparatus 10. The image data includes command data for operating carriage 200 and the like of image forming apparatus 10, and pixel data relating to the image to be formed.

[0053] The transport unit 100 is a unit that includes a transport mechanism for transporting the paper P. The transport unit 100 is also an example of a moving section that performs main scanning movement, which moves the carriage 200 relative to the paper P in the main scanning direction, and sub-scanning movement, which moves the carriage 200 relative to the paper P in the sub-scanning direction. The transport unit 100 includes a guide rod 19, a guide rail 29, etc.

[0054] The maintenance unit 500 has a maintenance and recovery mechanism for maintaining and recovering the ejection functions of the metallic ink ejection head 300 and the color ink ejection head 301. The maintenance and recovery mechanism includes a cap for covering the nozzle surface to protect the nozzles from drying out during periods when the image forming apparatus 10 is not forming images.

[0055] This cap includes a moisturizing cap that has the sole function of covering the nozzle surface and protecting it from drying out, and a suction cap that, in addition to the moisturizing cap function, is connected to a suction pump and sucks up thickened ink from the metallic ink ejection head 300 and color ink ejection head 301.

[0056] (Example of controller unit 3 functional configuration) Next, a description will be given of the functional configuration of the controller unit 3 included in the image forming apparatus 10. Fig. 4 is a block diagram showing an example of the functional configuration of the controller unit 3. As shown in Fig. 4, the controller unit 3 has an image processing unit 12 and a control unit 30.

[0057] The image processing unit 12 includes a data receiving unit 121 , a data generating unit 122 , and a data output unit 123 .

[0058] The data receiving unit 121 receives image data from the PC 26. The image data includes information such as the pattern or color of the image to be formed. The data generating unit 122 performs predetermined data processing such as CMYK conversion processing, gradation reduction processing, and image conversion processing on the image data received by the data receiving unit 121, and generates recording data for forming an image on paper P based on the image data. The data output unit 123 outputs the generated recording data to the control unit 30.

[0059] The control unit 30 includes a discharge control unit 14, a print mode receiving unit 21, an irradiation driving unit 22, a first driving unit 23, a second driving unit 24, and a formation control unit 25.

[0060] The ejection control unit 14 ejects ink from the metallic ink ejection head 300 and the color ink ejection head 301 based on the recording data. The print mode receiving unit 21 receives information related to the print mode. The print mode is information indicating color or monochrome printing, single-sided or double-sided printing of the paper P, etc.

[0061] The irradiation driver 22 drives the irradiation unit 400 to irradiate ultraviolet light.

[0062] The first drive unit 23 moves the carriage 200 in the sub-scanning direction, thereby moving the carriage 200 and the paper P relative to each other in the sub-scanning direction. The second drive unit 24 moves the carriage 200 in the main scanning direction, thereby moving the carriage 200 and the paper P relative to each other in the main scanning direction.

[0063] The formation control unit 25 receives recording data from the image processing unit 12, and controls the ejection control unit 14, the irradiation driving unit 22, the first driving unit 23, and the second driving unit 24 to eject ink corresponding to each pixel of the recording data from the metallic ink ejection head 300 and the color ink ejection head 301 according to the received recording data.

[0064] <Example of operation of image forming apparatus 10> Next, the operation of the image forming apparatus 10 will be described with reference to Fig. 5. Fig. 5 is a flowchart showing the operation of the image forming apparatus 10. Fig. 5 shows the operation triggered by the timing at which the image forming apparatus 10 receives image data from the PC 26, forms recording data, and then starts image formation control.

[0065] First, in step S51, the formation control unit 25 moves the carriage 200 in the sub-scanning direction and stops it at an initial position for recording an image.

[0066] Next, in step S52, the formation control unit 25 drives the lifting mechanism to move the carriage 200 to a height suitable for ink ejection by the metallic ink ejection head 300 and the color ink ejection head 301. The height refers to a position along the Z direction.

[0067] This height is, for example, a height at which the gap between the metallic ink ejection head 300 and the color ink ejection head 301 and the paper P is 1 mm. It is preferable that the formation control unit 25 controls the driving of the lifting mechanism based on a detection signal from a height sensor that detects the height of the metallic ink ejection head 300 and the color ink ejection head 301.

[0068] Subsequently, in step S53, the formation control unit 25 initializes the number of times n to n=1.

[0069] Subsequently, in step S54, the formation control unit 25 moves the carriage 200 in the outward direction as the first main scanning movement.

[0070] During the first main scanning movement, in step S55, the metallic ink ejection head 300 ejects metallic ink onto a first area of ​​the paper P. In this case, the metallic ink ejection head 300 corresponds to the outward path metallic ink ejection head.

[0071] Furthermore, during the first main scanning movement, the color ink ejection heads 301a and 301b eject color ink onto a first area of ​​the paper P in step S56.

[0072] Furthermore, during the first main scanning movement, in step S57, the irradiation unit 400 irradiates ultraviolet light onto the metallic ink and color ink ejected onto the first area of ​​the paper P. As a result, the metallic ink and color ink ejected onto the first area of ​​the paper P are cured and fixed to the paper P.

[0073] After the start of formation control, the irradiation unit 400a keeps the UV lamp on and continues to irradiate ultraviolet rays. When the irradiation unit 400a faces the metallic ink and color ink ejected onto the first region of the paper P, the metallic ink and color ink are irradiated with ultraviolet rays. The irradiation unit 400a facing the metallic ink and color ink ejected onto the first region of the paper P means that the first region and the irradiation unit 400a overlap in the direction in which the paper P is viewed in a plane.

[0074] However, the irradiation unit 400 may be controlled to turn on the UV lamp only when the irradiation unit 400 faces the metallic ink and color ink ejected onto the first area of ​​the paper P, and to turn off the UV lamp at other times.

[0075] These points also apply to the subsequent irradiation of ultraviolet light by the irradiation unit 400a.

[0076] On the carriage 200, on the −X direction side of the metallic ink ejection head 300, a color ink ejection head 301a, a color ink ejection head 301b, and an irradiation unit 400a are provided in this order from the downstream side to the upstream side of the outgoing path in the main scanning movement.

[0077] Therefore, during the first main scanning movement, which is the outward main scanning movement, the metallic ink ejection head 300 ejects metallic ink, and the color ink ejection heads 301a and 301b eject color inks, in that order, onto the first region. After that, when the irradiation unit 400a faces the metallic ink and color ink ejected onto the first region, ultraviolet light is irradiated.

[0078] The metallic ink ejection head 300 ejects metallic ink before the color ink ejection head 301 ejects color ink. Therefore, during the first main scanning movement, the time from ejection of the metallic ink ejected onto the first region of the paper P to the start of hardening is ensured to be longer than the time from ejection of the color ink to the start of hardening.

[0079] After the first main scanning movement is completed, the formation control unit 25 stops the carriage 200.

[0080] Subsequently, in step S58, the formation control unit 25 moves the carriage 200 in the backward direction as the second main scanning movement.

[0081] During the second main scanning movement, in step S59, the metallic ink ejection head 300 ejects metallic ink onto the first area of ​​the paper P. The metallic ink ejection head 300 corresponds to the metallic ink ejection head for the return pass.

[0082] Furthermore, during the second main scanning movement, the color ink ejection head 301 ejects color ink onto the first area of ​​the paper P in step S60.

[0083] Furthermore, during the second main scanning movement, in step S61, the irradiation unit 400 irradiates ultraviolet light onto the metallic ink and color ink ejected onto the first area of ​​the paper P. As a result, the metallic ink and color ink ejected onto the first area of ​​the paper P are cured and fixed to the paper P, and an image is formed on the first area of ​​the paper P.

[0084] On the carriage 200, on the +X direction side of the metallic ink ejection head 300, a color ink ejection head 301c, a color ink ejection head 301d, and an irradiation unit 400b are provided in this order from the downstream side to the upstream side on the return path of the main scanning movement.

[0085] Therefore, during the second main scanning movement, which is the return path main scanning movement, the metallic ink ejection head 300 ejects metallic ink, and the color ink ejection heads 301c and 301d eject color inks, in that order, onto the first region. After that, the irradiation unit 400b can irradiate ultraviolet light onto the metallic ink and color ink ejected onto the first region.

[0086] The metallic ink ejection head 300 ejects metallic ink before the color ink ejection head 301 ejects color ink. Therefore, during the second main scanning movement, the time from ejection of the metallic ink to the start of curing is longer than the time from ejection of the color ink to the start of curing.

[0087] Note that the first main scanning movement does not have to be the first main scanning movement, but simply refers to the main scanning movement in which metallic ink is ejected.Similarly, the second main scanning movement does not have to be the second main scanning movement, but simply refers to the main scanning movement in which ultraviolet light is irradiated onto the metallic ink after the first main scanning movement.

[0088] After the second main scanning movement is completed, the formation control unit 25 stops the carriage 200.

[0089] Subsequently, in step S62, the formation control unit 25 determines whether or not to end the operation. The formation control unit 25 can determine the end of the operation by, for example, determining whether or not the number of main scanning movements has reached a predetermined number.

[0090] If it is determined in step S62 that the process is to be ended (step S62, Yes), the formation control unit 25 ends the formation control.

[0091] On the other hand, if it is determined not to end (step S62, No), in step S63, the formation control unit 25 moves the carriage 200 in the sub-scanning direction by a predetermined sub-scanning width. This sub-scanning width is approximately equal to the length of the nozzle rows 300n and 301n along the sub-scanning direction.

[0092] Next, in step S64, the formation control unit 25 adds 1 to the number of times n. Thereafter, the formation control unit 25 performs the operations from step S54 onwards again. However, while the above description of the operations from steps S54 to S61 showed the case where n=1, from n=2 onwards, the number of times number (nth time) of the main scanning movement and the area number (nth area) increase according to the number of times n. Note that in this embodiment, since images are formed in the same area by the main scanning movement in the forward and backward passes, the number of times number of the main scanning movement is (n×2−1) on the forward pass and (n×2) on the backward pass according to the number of times n.

[0093] Thereafter, the image forming apparatus 10 can form an image in a predetermined area on the paper P by performing forward and backward main scanning movements and sub-scanning movements until the formation of the image on the paper P is completed.

[0094] FIG. 6 is a diagram showing the state of image formation on paper P, and FIGS. 6(a) to 6(d) are diagrams showing an example of image formation in the first to fourth main scanning movements.

[0095] First, the carriage 200 performs a first main scanning movement in the outward direction. During this movement, the metallic ink ejection head 300 ejects metallic ink, and the color ink ejection heads 301a and 301b eject color inks, in that order, onto the first region 61. Thereafter, the irradiation unit 400a irradiates the first region 61 with ultraviolet light. As a result, an image 61a is formed in the first region 61 by the first main scanning movement, as shown in FIG. 6(a).

[0096] Next, the carriage 200 performs a second main scanning movement in the backward direction. During this movement, the metallic ink ejection head 300 ejects metallic ink, and the color ink ejection heads 301c and 301d eject color inks, in that order, onto the first region 61. Thereafter, the irradiation unit 400b irradiates the first region 61 with ultraviolet light.

[0097] 6(b), an image 61b is formed in the first region 61 by the second main scanning movement. The color ink ejection head 301 may eject color ink onto the metallic ink ejected in the first region 61, or may eject color ink to complement the region in the first region 61 where metallic ink has not been ejected.

[0098] Next, the carriage 200 performs a sub-main scanning movement, and then performs a main scanning movement in the outgoing path as a third main scanning movement. During this movement, the metallic ink ejection head 300 ejects metallic ink, and the color ink ejection heads 301a and 301b eject color inks, in that order, onto the second region 62. The second region 62 is an area located downstream in the sub-scanning direction (toward the +Y direction) from the first region 61 by the sub-scanning width. Thereafter, the irradiation unit 400a irradiates the second region 62 with ultraviolet light. As a result, an image 61c is formed in the second region 62 by the third main scanning movement, as shown in FIG. 6(c).

[0099] Next, the carriage 200 performs a fourth main scanning movement in the backward direction. During this movement, the metallic ink ejection head 300 ejects metallic ink, and the color ink ejection heads 301c and 301d eject color inks, in that order, onto the second region 62. Thereafter, the irradiation unit 400b irradiates the second region 62 with ultraviolet light.

[0100] As a result, an image 61d is formed in the second region 62 by the fourth main scanning movement, as shown in FIG. 6(d).

[0101] In this way, image formation is repeated in each area with each main scanning movement, and an image is formed in a predetermined area of ​​the paper P.

[0102] (Operations and Effects of Image Forming Apparatus 10) Next, the effects of the image forming apparatus 10 will be described.

[0103] When forming images using inks such as metallic inks containing metal particles, it is important to improve the glossiness of the metallic ink. In particular, UV-curable inks tend to become thick, and the glossiness varies depending on the thickness, so there is room for improvement in glossiness.

[0104] As a result of extensive research by the inventors into the glossiness of such metallic ink, it was found that the glossiness of the image can be improved by extending the time between the ejection of the metallic ink and the irradiation of light by the irradiation unit 400. The reason for this is presumed to be as follows.

[0105] If the metallic ink is irradiated with light immediately after it lands on the medium, the metallic ink will harden immediately after it lands on the paper P. On the other hand, if the time between when the metallic ink lands on the paper P and when it is irradiated with light is lengthened, the metallic ink will wet and spread on the paper P before it hardens. As a result, the ink film thickness becomes thinner, and the numerous metal foil flakes contained in the metallic ink tend to be oriented parallel to the medium. Furthermore, the numerous metal foil flakes oriented parallel to the medium tend to reflect light in the same direction without scattering it, improving the glossiness of the image.

[0106] Therefore, the image forming apparatus 10 according to this embodiment includes an ink ejection head (liquid ejection head) that ejects ink (liquid) onto paper P (recording medium), an irradiation unit 400 (irradiation section) that irradiates the ink on the paper P with ultraviolet light (light), and a carriage 200 that is provided with the ink ejection head and irradiation unit 400. The image forming apparatus 10 also includes a transport unit 100 (movement section) that performs main scanning movement to move the carriage 200 relative to the paper P in the main scanning direction, and sub-scanning movement to move the carriage 200 relative to the paper P in a sub-scanning direction perpendicular to the main scanning direction.

[0107] The ink includes metallic ink and color ink. The ink ejection head ejects color ink during the same main scanning movement onto an area of ​​the paper P onto which the metallic ink has been ejected, and the irradiation unit 400 irradiates the area onto which the metallic ink and color ink have been ejected with ultraviolet light during the same main scanning movement.

[0108] This allows the ink ejection head to eject the metallic ink before ejecting the color ink, ensuring a longer time between ejection of the metallic ink and the start of hardening during main scanning compared to the time between ejection of the color ink and the start of hardening. As a result, the glossiness of images formed using the metallic ink is improved, enabling the expression of colorful, high-gloss images like metallic colors.

[0109] Furthermore, in this embodiment, in order to ensure a long time from the ejection of the metallic ink until the start of curing, the speed of the carriage 200 is not slowed down, and the carriage 200 is not stopped. As a result, it is possible to increase the glossiness of the image while ensuring high productivity in image formation.

[0110] In this embodiment, the main scanning movement includes movement in both the forward and backward directions, the liquid ejection head includes a metallic ink ejection head 300 that ejects metallic ink and color ink ejection heads 301a, 301b, 301c, and 301d that eject color ink, and the irradiation unit 400 includes irradiation units 400a and 400b (multiple irradiation sections).

[0111] On both sides of the metallic ink ejection head 300, the carriage 200 is provided with a color ink ejection head 301a, a color ink ejection head 301b, and an irradiation unit 400a, in that order from the side closest to the metallic ink ejection head 300, and also with a color ink ejection head 301c, a color ink ejection head 301d, and an irradiation unit 400b, in that order.

[0112] This allows the metallic ink and color ink to harden for each image formation in the forward and backward directions during main scanning movement, and the metallic ink and color ink are layered to ensure the amount of ink on the paper P, thereby increasing the glossiness of the image and ensuring high productivity in image formation.

[0113] In this embodiment, an example is shown in which metallic ink and color ink are formed in the same area on the forward and return passes, but images may be formed in different areas that are offset in the sub-scanning direction on the forward and return passes. In this case, too, curing that can increase the glossiness of the image and ensure high productivity can be achieved.

[0114] Furthermore, in this embodiment, a configuration using ultraviolet curable ink has been exemplified, but the present invention is not limited to this. For example, ink that is cured by light energy such as infrared light or thermal energy may be used, but from the viewpoint of curing efficiency, it is preferable to use ultraviolet curable ink.

[0115] In addition, in this embodiment, the operation of the image forming apparatus in which the carriage is moved in both the main scanning direction and the sub-scanning direction is exemplified, but this is not limiting. For example, it is also possible to configure the carriage to move in the main scanning direction and the paper P to move in the sub-scanning direction.

[0116] 7 is a perspective view showing another example of the configuration of such an image forming apparatus, in which the image forming apparatus is partially seen through from diagonally above.

[0117] 7, image forming apparatus 10a includes apparatus main body 101, feeding device 102, and winding device 103. Feeding device 102 is a medium supplying device that supplies rolled sheet-like paper P located below apparatus main body 101. The rolled paper P is an example of a recording medium.

[0118] The feeding device 102 holds a roll 112 with paper wound around a hollow shaft 115. The winding device 103 is provided with a hollow shaft 114 for winding up the paper, and the roll 112 is wound up around this hollow shaft 114. The feeding device 102 and the winding device 103 may be configured integrally with the device main body 101 rather than being separate entities.

[0119] The feeding device 102 supplies paper P into the device main body 101. Inside the device main body 101, an image forming unit 104 is arranged, which forms an image on paper P supplied in the transport direction indicated by the arrow B. The image forming unit 104 has guide members, a guide rod 1 and a guide stay 2, suspended between both side plates, and these guide rod 1 and guide stay 2 support a carriage 200 so that it can move in the main scanning direction indicated by the arrow A. A winding device 103 winds up the paper P on which an image has been formed.

[0120] A main scanning motor 8, which is a drive source for reciprocating the carriage 200, is disposed on one side in the main scanning direction. A timing belt 11 is wound around a drive pulley 9 that is rotationally driven by the main scanning motor 8 and a driven pulley 20 that is disposed on the other side in the main scanning direction. A belt holding portion of the carriage 200 is fixed to the timing belt 11, and the carriage 200 is reciprocated in the main scanning direction by driving the main scanning motor 8.

[0121] Even with such a configuration of the image forming apparatus 10a, by applying the carriage 200 shown in FIG. 2, the same effects as those of the image forming apparatus 10 described above can be obtained.

[0122] In the above-described embodiment, a configuration in which the carriage 200 moves in both the main scanning direction and the sub-scanning direction, and a configuration in which the carriage moves in the main scanning direction and the paper P moves in the sub-scanning direction are exemplified, but the present invention is not limited to these. As long as the paper P and the carriage can move relative to each other, a configuration in which the paper P moves in both the main scanning direction and the sub-scanning direction, or a configuration in which the paper P moves in the main scanning direction and the carriage moves in the sub-scanning direction, are also possible.

[0123] [Second embodiment] Next, an image forming apparatus 10b according to a second embodiment will be described. Note that the same components as those described in the first embodiment are given the same part numbers, and duplicated descriptions will be omitted where appropriate.

[0124] The image forming apparatus 10b is capable of bidirectional printing, forming images by main scanning movements in both outbound and inbound directions. The overall configuration of the image forming apparatus 10b can be applied to the image forming apparatus 10 or the image forming apparatus 10a described above. The image forming apparatus 10b differs from the image forming apparatus 10 or the image forming apparatus 10a in the arrangement of the ink ejection heads on the carriage.

[0125] Fig. 8 is a diagram showing an example of the configuration of a carriage 200b included in the image forming apparatus 10b. As shown in Fig. 8, the carriage 200b includes metallic ink ejection heads 300a and 300b that eject metallic ink, and color ink ejection heads 301a, 301b, 301c, and 301d that eject color inks.

[0126] On the carriage 200b, the metallic ink ejection head 300a, the color ink ejection head 301a, the color ink ejection head 301b, and the irradiation unit 400a are arranged in this order from downstream to upstream on the outgoing path of the main scanning movement, while the metallic ink ejection head 300b, the color ink ejection head 301c, the color ink ejection head 301d, and the irradiation unit 400b are arranged in this order from downstream to upstream on the return path of the main scanning movement.

[0127] This arrangement allows the ink ejection head in the image forming device 10b to eject the metallic ink before ejecting the color ink, ensuring a longer time between ejection of the metallic ink and the start of curing than the time between ejection of the color ink and the start of curing during main scanning movement, thereby improving the glossiness of images formed using the metallic ink.

[0128] Furthermore, in this embodiment, the distance between the metallic ink ejection head and the irradiation unit in the main scanning direction is longer than in the arrangement of the metallic ink ejection head, color ink ejection head, and irradiation unit on the carriage 200 shown in the first embodiment. This ensures a longer time between the ejection of metallic ink by the metallic ink ejection head and the irradiation of ultraviolet light, thereby improving the glossiness of images formed using metallic ink.

[0129] Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to such specific embodiments, and various modifications and changes are possible within the scope of the gist of the embodiments of the present invention described in the claims.

[0130] The embodiments also include an image forming method. For example, the image forming method includes the steps of: ejecting a liquid onto a recording medium using a liquid ejection head; irradiating the liquid on the recording medium with light using an irradiation unit; performing a main scanning movement in which a carriage equipped with the liquid ejection head and the irradiation unit moves relative to the recording medium in a main scanning direction; and performing a sub-scanning movement in which the carriage moves relative to the recording medium in a sub-scanning direction perpendicular to the main scanning direction. The liquid includes metallic ink and color ink. The liquid ejection head ejects the color ink onto an area of ​​the recording medium onto which the metallic ink was ejected during the main scanning movement, and the irradiation unit irradiates the area with light during the main scanning movement. Such an image forming method can achieve the same effects as the image forming apparatus described above. Note that such an image forming method may be implemented using a CPU, a circuit such as an LSI, an IC card, or a standalone module.

[0131] The embodiments also include an image forming program. For example, the image forming program causes a computer to execute a process of: ejecting a liquid onto a recording medium using a liquid ejection head; irradiating the liquid on the recording medium with light using an irradiation unit; performing a main scanning movement in which a carriage equipped with the liquid ejection head and the irradiation unit moves relatively to the recording medium in a main scanning direction; and a sub-scanning movement in which the carriage moves relatively to the recording medium in a sub-scanning direction perpendicular to the main scanning direction, wherein the liquid includes metallic ink and color ink; and the liquid ejection head ejects the color ink onto an area of ​​the recording medium onto which the metallic ink was ejected during the main scanning movement, during the same main scanning movement; and the irradiation unit irradiates the area with light during the same main scanning movement. Such an image forming program can achieve the same effect as the image forming apparatus described above.

[0132] Furthermore, all ordinal numbers, quantitative numbers, and other figures used in the description of the embodiments are merely examples for specifically explaining the technology of the present invention, and the present invention is not limited to the exemplified figures. Furthermore, the connection relationships between the components are merely examples for specifically explaining the technology of the present invention, and the connection relationships for realizing the functions of the present invention are not limited to these.

[0133] The division of blocks in the functional block diagram is an example, and multiple blocks may be realized as a single block, one block may be divided into multiple blocks, and / or some functions may be moved to another block.Furthermore, the functions of multiple blocks having similar functions may be processed in parallel or in time-sharing by a single piece of hardware or software.

[0134] Furthermore, each function of the above-described embodiments can be realized by one or more processing circuits. Here, the term "processing circuit" in this specification includes a processor programmed to perform each function by software, such as a processor implemented by an electronic circuit, as well as devices such as an ASIC (Application Specific Integrated Circuit), a DSP (Digital Signal Processor), an FPGA (Field Programmable Gate Array), and conventional circuit modules designed to perform each of the above-described functions. [Explanation of symbols]

[0135] 3 Controller Unit 10, 10a, 10b Image forming device 12 Image processing section 13 Mounting table 14 Discharge control section 18a, 18b side plate 19 Guide rod 21 Print mode reception unit 22 Irradiation drive unit 23 First drive unit 24 Second drive unit 25 Formation Control Department 29 Guide rail 61 1st area Images 61a, 61b, 61c, and 61d 62 Second area 100 Transport unit (an example of a moving part) 200 carriages 300, 300a, 300b metallic ink ejection head 301, 301a, 301b, 301c, 301d Color ink ejection heads 400a, 400b irradiation unit (an example of an irradiation unit) 300n, 301n nozzle rows [Prior art documents] [Patent documents]

[0136] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-230626

Claims

1. a liquid ejection head that ejects liquid onto a recording medium; an irradiation unit that irradiates the liquid on the recording medium with light; a carriage provided with the liquid ejection head and the irradiation unit; a moving unit that performs main scanning movement to move the carriage relative to the recording medium in a main scanning direction, and sub-scanning movement to move the carriage relative to the recording medium in a sub-scanning direction perpendicular to the main scanning direction, the liquid includes a metallic ink and a color ink, the liquid ejection head ejects the color ink onto an area onto which the metallic ink has been ejected during the main scanning movement of the recording medium, during the same main scanning movement; the irradiation unit irradiates the light onto the area onto which the metallic ink and the color ink are ejected during the same main scanning movement; the main scanning movement includes movement in both a forward and a backward direction, the liquid ejection heads include a metallic ink ejection head that ejects the metallic ink and a color ink ejection head that ejects the color inks, The irradiation unit includes a plurality of irradiation units, The image forming apparatus is characterized in that the carriage is provided with the color ink ejection heads and the irradiation unit on both sides of the metallic ink ejection head, in that order from the side closest to the metallic ink ejection head.

2. 2. The image forming apparatus according to claim 1, wherein the metallic ink and the color ink are both ultraviolet curable.

3. 3. The image forming apparatus according to claim 1, wherein at least one of the metallic ink and the color ink contains a solvent.

4. 4. The image forming apparatus according to claim 1, wherein at least one of the metallic ink and the color ink contains water.

5. ejecting the liquid from a liquid ejection head onto a recording medium; irradiating the liquid on the recording medium with light by an irradiation unit; a main scanning movement in which a carriage provided with the liquid ejection head and the irradiation unit is moved relative to the recording medium in a main scanning direction, and a sub-scanning movement in which the carriage is moved relative to the recording medium in a sub-scanning direction perpendicular to the main scanning direction, the liquid includes a metallic ink and a color ink, the liquid ejection head ejects the color ink onto an area onto which the metallic ink has been ejected during the main scanning movement of the recording medium, during the same main scanning movement; the irradiation unit irradiates the light onto the area onto which the metallic ink and the color ink are ejected during the same main scanning movement; the main scanning movement includes movement in both a forward and a backward direction, the liquid ejection heads include a metallic ink ejection head that ejects the metallic ink and a color ink ejection head that ejects the color inks, The irradiation unit includes a plurality of irradiation units, The image forming method according to the present invention, wherein the carriage is provided with the color ink ejection heads and the irradiation unit on both sides of the metallic ink ejection head in this order from the side closest to the metallic ink ejection head.

6. A liquid is ejected onto a recording medium by a liquid ejection head, an irradiation unit irradiating the liquid on the recording medium with light; causing a computer to execute a process of performing a main scanning movement in which a carriage provided with the liquid ejection head and the irradiation unit is moved relative to the recording medium in a main scanning direction, and a sub-scanning movement in which the carriage is moved relative to the recording medium in a sub-scanning direction perpendicular to the main scanning direction; the liquid includes a metallic ink and a color ink, the liquid ejection head ejects the color ink onto an area onto which the metallic ink has been ejected during the main scanning movement of the recording medium, during the same main scanning movement; the irradiation unit irradiates the light onto the area onto which the metallic ink and the color ink are ejected during the same main scanning movement; the main scanning movement includes movement in both a forward and a backward direction, the liquid ejection heads include a metallic ink ejection head that ejects the metallic ink and a color ink ejection head that ejects the color inks, The irradiation unit includes a plurality of irradiation units, The image forming program is characterized in that the carriage is provided with the color ink ejection head and the irradiation unit on both sides of the metallic ink ejection head, in that order from the side closest to the metallic ink ejection head.

Images