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

Abstract

Provided is an image forming apparatus capable of improving washing fastness even if grayscale is expressed on a fabric. An image forming apparatus 1 according to the present disclosure comprises: a color head 12a that discharges a color ink containing a pigment and a resin; a white head 12b that discharges a white ink containing a pigment and a resin; and a control unit. The control unit causes the color ink to be discharged from the color head 12a onto a fabric, and causes the white ink to be discharged from the white head 12b in a region in which the color ink has been discharged.

Description

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

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

[0002] Patent Document 1 discloses an inkjet printing method for improving the color development property of color ink by discharging white ink and then discharging color ink thereon.

[0003] Japanese Patent Application Laid-Open No. 2016-089288

[0004] In the fabric to which ink is applied, the ink may be peeled off by washing, and there is a problem in washing fastness. As a method for improving the washing fastness, it is conceivable to increase the application amount of the ink containing resin. On the other hand, when expressing grayscale on the fabric, if the application amount of the ink is increased, the color development becomes too strong, and it may be difficult to express grayscale.

[0005] Therefore, an object of the present disclosure is to provide an image forming apparatus, an image forming method, and an image forming program that can improve the washing fastness when expressing grayscale on a fabric.

[0006] To achieve the above object, the image forming apparatus of the present disclosure includes a color head that discharges color ink containing a pigment and a resin, a white head that discharges white ink containing a pigment and a resin, and a control unit. The control unit discharges the color ink from the color head onto the fabric and discharges the white ink from the white head onto the area where the color ink has been discharged.

[0007] The image forming method of the present disclosure includes a control step. The control step discharges color ink containing a pigment and a resin from a color head onto a fabric and discharges white ink containing a pigment and a resin from a white head onto the area where the color ink has been discharged.

[0008] The image forming program of the present disclosure causes a computer of an image forming apparatus, which includes a color head for ejecting color ink containing pigment and resin, and a white head for ejecting white ink containing pigment and resin, to execute a control procedure, wherein the control procedure is characterized by causing the color ink to be ejected from the color head onto the fabric, and causing the white ink to be ejected from the white head onto the area where the color ink has been ejected.

[0009] According to the image forming apparatus, image forming method, and image forming program of this disclosure, wash fastness can be improved even when representing grayscale on a fabric.

[0010] Figure 1 is a schematic perspective view showing the configuration of an example of an image forming apparatus according to the present disclosure. Figure 2 is a plan view showing the internal structure of the image forming apparatus according to the present disclosure in perspective. Figure 3 is a side view showing the internal structure of the image forming apparatus according to the present disclosure in perspective. Figure 4 is a block diagram showing an example of the configuration of the control unit of the image forming apparatus according to the present disclosure. Figure 5 is a flowchart showing an example of a process in the image forming method according to the present disclosure.

[0011] Embodiments of this disclosure will now be described. However, this disclosure is not limited to the embodiments described below. In the following figures, the same parts are denoted by the same reference numerals. Furthermore, unless otherwise specified, the descriptions of each embodiment may be used interchangeably. Furthermore, unless otherwise specified, the configurations of each embodiment are combinable. Also, in the programs of this disclosure described later, the term "procedure" can be read as "process," for example.

[0012] In this disclosure, the term "grayscale" is not limited to a representation of tones from white to black using gradients, but may also refer to a representation of tones of any color other than white and black using gradients. Furthermore, the number of tones is not limited to 256, but may be any number.

[0013] First, we will explain the color ink and white ink used in this disclosure.

[0014] The aforementioned color ink and the aforementioned white ink each contain a pigment and a resin, respectively.

[0015] The pigment is appropriately selected, for example, according to the color of the ink. The pigment is not particularly limited, and examples include carbon black, inorganic pigments, and organic pigments. Examples of carbon black include furnace black, lamp black, acetylene black, and channel black. Examples of inorganic pigments include titanium dioxide, iron oxide-based inorganic pigments, and carbon black-based inorganic pigments. Examples of organic pigments include azo pigments such as azo lakes, insoluble azo pigments, condensed azo pigments, and chelate azo pigments; polycyclic pigments such as phthalocyanine pigments, perylene and perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, thioindigo pigments, isoindolinone pigments, and quinophthalone pigments; dye lake pigments such as basic dye-type lake pigments and acid dye-type lake pigments; nitro pigments; nitroso pigments; aniline black daylight fluorescent pigments; and the like. Other pigments that can be dispersed in the aqueous phase may also be used. Specific examples of these pigments include, for example, C.I. Pigment White 1, 4, 5, 6, 7, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, and 28; C.I. Pigment Black 1, 6, and 7; C.I. Pigment Yellow 1, 2, 3, 12, 13, 14, 15, 16, 17, 55, 74, 78, 150, 151, 154, 180, 185, and 194; C.I. Pigment Orange 31 and 43; C.I. Pigment reds 2, 3, 5, 6, 7, 12, 15, 16, 48, 48:1, 53:1, 57, 57:1, 112, 122, 123, 139, 144, 146, 149, 150, 166, 168, 175, 176, 177, 178, 184, 185, 190, 202, 209, 221, 222, 224 and 238; C.I. Pigment violet 19 and 196; C.I. Pigment blues 1, 2, 3, 15, 15:1, 15:2, 15:3, 15:4, 16, 22 and 60; C.I. Pigment greens 7 and 36; and solid solutions of these pigments are also examples.

[0016] The pigment may be dispersed in a solvent by a resin dispersant (also called a resin-dispersed pigment). The resin dispersant may be, for example, a conventionally known polymer dispersant (also called a pigment dispersion resin or resin dispersant, etc.). In addition, in the aqueous ink of this disclosure, the pigment may be encapsulated by a polymer. The resin dispersant may be, for example, one containing at least one of methacrylic acid and acrylic acid as a monomer, and commercially available products may be used. The resin dispersant may be, for example, a hydrophobic monomer such as styrene, styrene derivatives, vinylnaphthalene, vinylnaphthalene derivatives, or aliphatic alcohol esters of α,β-ethylenically unsaturated carboxylic acids, or a block copolymer, graft copolymer, or random copolymer or a salt thereof, consisting of two or more monomers selected from the group consisting of acrylic acid, acrylic acid derivatives, maleic acid, maleic acid derivatives, itaconic acid, itaconic acid derivatives, fumaric acid, or fumaric acid derivatives. Examples of the aforementioned commercially available products include "Johncryl® 611", "Johncryl® 60", "Johncryl® 586", "Johncryl® 687", "Johncryl® 63", and "Johncryl® HPD296" manufactured by Johnson Polymer Co., Ltd.; "Disperbyk 190" and "Disperbyk 191" manufactured by Bic Chemie; and "Solspers 20000" and "Solspers 27000" manufactured by Zeneca.

[0017] A method for dispersing the pigment using the aforementioned pigment dispersion resin includes, for example, a method of dispersing the pigment using a dispersion apparatus. The dispersion apparatus used for dispersing the pigment is not particularly limited as long as it is a general-purpose dispersion machine, but examples include ball mills, roll mills, sand mills (e.g., high-speed type), etc.

[0018] The pigment may be, for example, a self-dispersing pigment. The self-dispersing pigment is such that, for example, at least one of a hydrophilic functional group such as a carbonyl group, a hydroxyl group, a carboxylic acid group, a sulfonic acid group, a phosphate group, or a salt thereof is introduced into the pigment particles by chemical bonding, either directly or via other groups, so that it can be dispersed in water without the use of a dispersant. The self-dispersing pigment may be one in which the pigment has been treated by the method described in, for example, Japanese Patent Publication No. 8-3498, Japanese Patent Publication No. 2000-513396, Japanese Patent Publication No. 2008-524400, Japanese Patent Publication No. 2009-515007, Japanese Patent Publication No. 2011-515535, etc. The raw material for the self-dispersing pigment may be either an inorganic pigment or an organic pigment. Examples of pigments suitable for the above treatment include carbon black such as "MA8" and "MA100" manufactured by Mitsubishi Chemical Corporation. The self-dispersing pigment may be, for example, a commercially available product. Examples of the aforementioned commercially available products include: "CAB-O-JET® 200", "CAB-O-JET® 250C", "CAB-O-JET® 260M", "CAB-O-JET® 270Y", "CAB-O-JET® 300", "CAB-O-JET® 400", "CAB-O-JET® 450C", "CAB-O-JET® 465M", and "CAB-O-JET® 470Y" from Cabot Corporation; "BONJET® BLACK CW-2" and "BONJET® BLACK CW-3" from Orient Chemical Industries, Ltd.; and "LIOJET® WD BLACK" from Toyo Ink Manufacturing Co., Ltd. Examples include "002C," etc.

[0019] The aforementioned pigment may be a single pigment used alone, or two or more pigments may be used.

[0020] The resin may, for example, be a resin included as a component of a resin emulsion. The resin emulsion is composed of, for example, the resin and a dispersion medium (for example, water). The resin is dispersed in the dispersion medium with a specific particle size, rather than being dissolved.

[0021] Examples of the aforementioned resins include acrylic acid resins, maleic acid ester resins, vinyl acetate resins, carbonate-type resins, polycarbonate-type resins, styrene-type resins, ethylene-type resins, polyethylene-type resins, propylene-type resins, polypropylene-type resins, urethane-type resins, polyurethane-type resins, and copolymer resins thereof. One type of resin may be used, or two or more types of resins may be used.

[0022] The ink may further contain conventionally known additives as needed. Examples of such additives include solvents, crosslinking agents, wetting agents, surfactants, pH adjusters, viscosity modifiers, surface tension modifiers, and antifungal agents.

[0023] <Image Forming Apparatus> Next, an image forming apparatus according to the present disclosure will be described. The image forming apparatus according to the present disclosure may be an integrated type having a color head, a white head, and a control unit inside a single housing, or it may be a system including separate and independent color heads, white heads, and control units.

[0024] Figure 1 shows an example of the configuration of the integrated image forming apparatus. As shown in Figure 1, the image forming apparatus 1 includes an ink set housing 2 and a control unit 5. The housing of the image forming apparatus 1 is also equipped with an ink ejection unit 3, which will be described later. Optionally, it also includes a heating unit 4. The heating unit 4 may be a separate device from the apparatus 1, as shown in Figure 1, or it may be included inside the apparatus 1.

[0025] The image forming apparatus 1 is an inkjet printing apparatus that ejects droplets of the color ink and the white ink from an ink ejection unit 3 onto a fabric. The ink ejection unit 3 is an inkjet head of either a line head or serial head type. In the image forming apparatus 1, the droplets are ejected onto the fabric based on image data to form an image.

[0026] The ink set housing section 2 is capable of housing an ink set. The ink set includes the color ink and the white ink. However, the ink set housing section 2 may include, for example, a color ink set housing section capable of housing the color ink set and a white ink set housing section capable of housing the white ink set, each as a separate configuration.

[0027] The ink ejection unit 3 includes a color head 12a and a white head 12b. The ink ejection unit 3 ejects the color ink and the white ink stored in the ink set storage unit 2 onto the fabric using an inkjet method. The fabric may be, for example, a fabric to which a pretreatment liquid for agglomerating the ink has been applied, or a fabric to which the pretreatment liquid has not been applied. The pretreatment liquid is, for example, a pretreatment liquid applied to the fabric in a region including the ink ejection area before ejecting the pigment-containing ink, and contains the resin. The image forming apparatus 1 is not limited to a configuration in which the ink ejection unit 3 also serves as the color head 12a and the white head 12b. That is, the image forming apparatus 1 may include the color head 12a and the white head 12b as separate components, with a color ink ejection means provided inside the color head 12a and a white ink ejection means provided inside the white head 12b.

[0028] An operation panel 6 having a display device 7 and a button 8 is provided at the front right end of the ink ejection unit 3. The display device 7 is, for example, a liquid crystal display. The button 8 inputs an image formation start signal to the control unit 5. In addition to or instead of the button 8, the display device 7, for example, a touch panel, may receive user input and input an image formation start signal to the control unit 5. The front wall of the housing 9 of the ink ejection unit 3 is provided with an opening 10 through which a platen 31 and the fabric held by the platen 31 can enter and exit. From this point onward, the front, rear, left, and right are as indicated by the arrows in Figure 1.

[0029] Figures 2 and 3 are a plan view and a side view, respectively, showing the internal structure of the image forming apparatus 1 shown in Figure 1. As shown in Figures 2 and 3, the ink ejection section 3 is equipped with an ink head 12 (color head 12a, white head 12b) having an array of inkjet nozzles, and a carriage 13 on which this ink head 12 is mounted. A pair of upper and lower guide rods 14 and 15 are installed in the left-right direction to guide this carriage 13.

[0030] A carriage motor 18, consisting of a stepping motor, is provided at the right end of the guide rods 14 and 15 to reciprocate the carriage 13 in the left-right direction. The carriage 13 is connected to a belt (not shown) that runs parallel to the guide rods 14 and 15. The belt is stretched between a pulley (not shown) connected to the carriage motor 18 and a pulley (not shown) provided at the left end of the guide rods 14 and 15. By driving the carriage motor 18, the ink head 12 and the carriage 13 are transported along the guide rods 14 and 15 in the left-right direction (main scanning direction). The carriage 13, the guide rods 14 and 15, the carriage motor 18, the pulleys, and the belt constitute the ink head transport mechanism.

[0031] The ink storage container (ink cartridge) housed in the ink set storage section 2 is connected to the ink head 12 via a supply tube. Figures 1 to 3 show examples where the ink ejection means is an ink head 12 having an inkjet nozzle row, but the ink ejection means may be any means capable of ejecting ink onto the fabric, such as a spray, a stamp for applying ink to the fabric, a brush, a roller, etc. The ink ejection means for ejecting the color ink and the ink ejection means for ejecting the white ink may be the same or different.

[0032] In the center of the ink ejection section 3 in the left-right direction, a pair of left and right guide rails (not shown) are arranged in the front-rear direction to guide the moving member 60 on which the platen 31 is mounted.

[0033] A platen motor 26 is provided between a pair of left and right guide rails near their front ends. A pulley 16 is fixed to the output shaft of the platen motor 26. A pulley 27 is supported at the bottom of the attachment section in front of the platen motor 26. A belt 17 is stretched over pulleys 16 and 27. Pulley 27 has a pulley 24 coaxially above it. A pulley 28 is rotatably supported below the ink ejection section 3. A belt 25 is stretched over pulleys 24 and 28. A moving member 60 is connected to the belt 25. The rotational drive of the platen motor 26 causes pulley 16 to rotate. The rotation of pulley 16 causes pulley 24 to rotate via belt 17. The rotation of pulley 24 is transmitted to belt 25, which transports the moving member 60 in the front-rear direction (sub-scanning direction) along the pair of left and right guide rails. The platen conveying mechanism is comprised of a platen motor 26, a pair of left and right guide rails, pulleys 16, 24, 27, and 28, and a belt 25.

[0034] The heating section 4 is provided with a heating means that heats the color ink and white ink application sections to promote drying. The heating means may be, for example, a non-contact heating means or a contact heating means. Examples of the non-contact heating means include ovens and belt conveyor ovens. Examples of the contact heating means include heat presses.

[0035] Next, the control unit 5 will be described using Figure 4. The control unit 5 is electrically connected via a bus 81 to a central processing unit (for example, a CPU (Central Processing Unit)) 87, a ROM (Read Only Memory) 88, a RAM (Random Access Memory) 89, an input interface 85, and an output interface 90. Buttons 8 and the like are electrically connected to the input interface 85. The output interface 90 is electrically connected to an ink head 12, a carriage motor 18, a platen motor 26, a display device (display) 7, and the like via drive circuits 91 to 94.

[0036] The CPU 87 performs various calculations and processes based on signals input by the button 8 and various programs and data in the ROM 88 and RAM 89. It then transmits data to each component of the ink ejection unit 3 via the output interface 90. The RAM 89 is a read / write volatile memory device that stores the results of various calculations performed by the CPU 87.

[0037] The control unit 5 controls the color head 12a and the white head 12b, in the first step, to discharge the color ink from the color head 12a onto the fabric, and after the first step, in the second step, to discharge the white ink from the white head into the area where the color ink was discharged. The first and second steps may be repeated. Performing the second step after the first step can improve wash fastness while maintaining grayscale representation when grayscale is used. Also, performing the second step after the first step can reduce the amount of white ink used, which is said to require frequent maintenance, thus reducing maintenance time.

[0038] The following are some possible reasons why wash fastness can be improved while maintaining grayscale representation: Increasing the amount of resin-containing ink increases the film density, making it easier for the fibers of the fabric to lie flatter. This reduces shedding of fibers during washing, thus tending to improve wash fastness. On the other hand, when representing grayscale, increasing the amount of white ink increases the color intensity, making it difficult to represent grayscale. Therefore, if the color ink is dispensed onto the fabric before the white ink is dispensed, wash fastness can be improved while maintaining grayscale representation. However, the above principle is merely a hypothesis, and this disclosure is not limited to the above principle.

[0039] The ejection of ink onto a fabric using the image forming apparatus of the present disclosure is carried out, for example, as follows. First, as the first step, the control unit 5 ejects (applies) the color ink onto the fabric. Specifically, while transporting the ink head 12 and the platen 31 by the ink head transport mechanism and the platen transport mechanism, an image is printed on the image forming area of ​​the fabric using the color ink.

[0040] In the first step, the control unit 5 may eject the color ink from the color head 12a in a concentration of, for example, 1.8 mg / cm² or more, or 3.7 mg / cm² or more, or in a concentration of 5.6 mg / cm² or less, or 4.7 mg / cm² or less.

[0041] Furthermore, in the first step, the control unit 5 may discharge, for example, 1.5 times or more, or 2.0 times or more, the amount of color ink from the color head 12a. Discharging 1.5 times or more of the color ink compared to the white ink improves, for example, wash fastness.

[0042] In the first step, the control unit 5 may eject the color ink from the color head 12a to form a color ink layer such that the color difference (ΔE) with the color of the fabric is 12 or less, or 6 or less. The color ink layer refers to, for example, the layer of color ink that has dried on the fabric. When the color difference is 12 or less, for example, the difference in color between the color of the fabric and the color of the area where the color ink has been ejected, as seen by the human eye, becomes smaller. Furthermore, when the color difference is 6 or less, for example, the difference in color between the color of the fabric and the color of the area where the color ink has been ejected, as seen by the human eye, becomes even smaller. In other words, the "uniformity of hue of the white ink printed surface," which will be described later, is improved.

[0043] Note that the state where the hue of the white ink printed surface is uniform means, for example, a state where the hue of the printed surface formed by discharging only the white ink onto the fabric is close to the hue of the printed surface formed by further discharging the white ink after discharging the color ink onto the fabric. More specifically, the state where the hue of the white ink printed surface is uniform means, for example, a state where the color difference (ΔE) between the color of the printed surface formed by discharging only the white ink onto the fabric and the color of the printed surface formed by further discharging the white ink after discharging the color ink onto the fabric is 12 or less, or 6 or less. When the chroma difference is 12 or less, for example, the color difference of the white ink printed surface when viewed by the human eye becomes small. Further, when the color difference is 6 or less, for example, the color difference of the white ink printed surface when viewed by the human eye becomes even smaller. Note that the color difference (ΔE) is calculated by, for example, the following formula (4). Color difference (ΔE) = { (a1* - a2*)2 + (b1* - b2*)2}1 / 2... (4) a1*: a* value of the printed surface formed by discharging only the white ink onto the fabric a2*: a* value of the printed surface formed by discharging the color ink and the white ink onto the fabric b1*: b* value of the printed surface formed by discharging only the white ink onto the fabric b2*: b* value of the printed surface formed by discharging the color ink and the white ink onto the fabric

[0044] Next, as the second step, the white ink containing the pigment and the resin is discharged onto the area where the color ink has been discharged. Specifically, while the ink head 12 and the platen 31 are being transported by the ink head transport mechanism and the platen transport mechanism, an image is printed using the white ink onto the area where the color ink has been discharged.

[0045] In the second step, the control unit 5 may cause the white ink of, for example, 1.8 mg / cm2 to 7.3 mg / cm2 to be discharged from the white head 12b.

[0046] In the second step, the control unit 5 may cause the white ink to be discharged from the white head 12b so as to form a grayscale image.

[0047] After the first step, the control unit 5 may execute the second step. The interval time between each step may be, for example, 6 seconds or more in order to reduce bleeding between the color ink ejected in the first step and the white ink described in the second step.

[0048] At least one of the ROM 88 and the RAM 89 of the control unit 5 stores various image data created by software and various data for each type of fabric such as T-shirts. When the operator instructs to perform printing, the image data is transmitted to the ink heads 12 (color head 12a and white head 12b) via the output interface 90, and color ink is ejected from the color head 12a and white ink is ejected from the white head 12b based on the image data, and printing on the fabric held by the platen 31 is performed.

[0049] In addition, after the first step and the second step, the control unit 5 may perform control to eject the color ink from the color head 12a to at least a part of the region where the white ink has been ejected in the third step.

[0050] Furthermore, for example, after the first step, the second step, and the third step, a heat treatment step for drying the color ink and the white ink may be performed. The heat treatment step may be performed by, for example, the heat treatment unit 4, and may be performed by non-contact heating means such as an oven or a belt conveyor oven, or may be performed by contact heating means such as a heat press machine.

[0051] <Image forming method> Next, the image forming method of the present disclosure will be described based on FIG. 5. FIG. 5 is a flowchart showing an example of the steps in the image forming method of the present disclosure. The image forming method of the present disclosure includes a control step as described above.

[0052] In the control step, the color ink is ejected from the color head 12a onto the fabric (S11). Next, in the control step, the white ink is ejected from the white head onto the region where the color ink has been ejected (S12). The control step is performed by, for example, the control unit 5 in the image forming apparatus of the present disclosure.

[0053] The image forming method disclosed herein may be carried out, for example, using the image forming apparatus shown in Figures 1 to 4 above. The control step may control, for example, the first step, the second step, and the third step.

[0054] The image forming method of the present disclosure may further include, for example, a heat treatment step (not shown) after the first and second steps, in which the ink is heat-fixed to the fabric. The heat treatment step is as described above.

[0055] <Image Forming Program>

[0056] This disclosure also provides a program for image formation. The program of this disclosure is a program that causes an image forming apparatus, which is a computer, to execute each step of the image forming method of this disclosure as a procedure. In this disclosure, "procedure" may be read as "process". Furthermore, the program of this embodiment may be recorded on a computer-readable recording medium, for example. The recording medium is not particularly limited and includes, for example, read-only memory (ROM), hard disk (HD), optical disc, etc.

[0057] The image forming program disclosed herein may be recorded, for example, on a computer-readable recording medium. The recording medium is, for example, a non-transitory computer-readable storage medium. The recording medium is not particularly limited and includes, for example, random access memory (RAM), read-only memory (ROM), hard disk (HD), flash memory (e.g., USB flash memory, SD / SDHC card, etc.), optical disc (e.g., CD-R / CD-RW, DVD-R / DVD-RW, BD-R / BD-RE, etc.), magneto-optical disk (MO), floppy disk (FD), etc. The program disclosed herein (for example, also referred to as a programming product or program product) may also be distributed, for example, from an external computer. The “distribution” may be, for example, distribution via a communication network or distribution via a wired connected device. The program disclosed herein may be installed and executed on the distributed device, or it may be executed without being installed.

[0058] Next, embodiments of this disclosure will be described together with comparative examples. However, this disclosure is not limited to or restricted by the embodiments and comparative examples described below.

[0059] [Examples 1-19 and Comparative Examples 1-4] Samples for Examples 1-19 and Comparative Examples 1-4 were prepared based on the conditions described in Table 1. Specifically, they were prepared by the following method.

[0060] <Pretreatment Process> First, a pretreatment solution was applied to the fabric (GILDAN, product number: GILDAN® Ultra cotton, material: 100% cotton) listed in Table 1 by spray application. The pretreatment solution used was a pretreatment solution containing resin, etc. (Brother Industries, Ltd., product number: GCX-4P) diluted to three times its original volume. The diluted pretreatment solution was applied to the image-forming surface of the T-shirt at a rate of 40 g per 14 x 16 inch using an automatic pretreatment application device (PRINTSYSTEM, product name: THE CUBE). Subsequently, pretreatment fixing was performed on the pretreatment solution application area using a heat press (STAHLS' Hotronix, product name: AIR FUSION IQ®). Pretreatment fixing was performed by heat treatment at a set temperature of 185°C and a set pressure of 31 psi for 35 seconds.

[0061] <Color Printing Process> Next, using a garment printer (Brother Industries, Ltd., model number: GTX-pro), color inks containing pigment, wetting agent, resin, and surfactant (Brother Industries, Ltd., model numbers: GCX-4M-1, GCX-4C-1, GCX-4K-1) were ejected into the area where the aforementioned pretreatment solution had been applied. The ejection amounts of the color inks are shown in Table 1.

[0062] <White Printing Process> Next, 90 seconds or more after the application of the color ink, white ink (manufactured by Brother Industries, Ltd., part number: GCX-4W), containing pigment, wetting agent, resin, and surfactant, was ejected using the garment printer described above into the area where the color ink had been ejected. The amount of white ink ejected is shown in Table 1.

[0063] <Heat Treatment Process> After the white printing process, the color ink and the white ink were heat-fixed to the printed area of ​​the T-shirt using a dryer (manufactured by ADELCO, product name: Drawer Drying Cabinet, product number: DDC-3A) set to 160°C. The heating time for the heat fixing was 3.5 minutes.

[0064] For the samples of Examples 1 to 19 and Comparative Examples 1 to 4, (a) the color difference between the fabric and the color ink ejection area, (b) wash fastness, (c) the color development increase rate, and (d) the uniformity of the hue of the white ink printed surface were evaluated by the following methods.

[0065] (a) Color difference between the fabric and the color ink ejection area The color difference between the fabric and the color ink ejection area after the aforementioned color printing process was measured using a CIE1976L*a*b* color space scale colorimeter (X-Rite PANTONE, part number: X-Rite eXact).

[0066] (b) Wash fastness The samples after the ink drying process described above were washed and dried under the following conditions: • Washing machine: MWI74140JB2 (manufactured by MAYTAG) Simultaneous washing weight: 1800 g to 2200 g Washing mode Washing program: Cotton, 60℃ Variable spin: 1400 Detergent used: Attack® synthetic laundry detergent (manufactured by Kao Corporation) • Tumble dryer: NH-D603 (manufactured by Panasonic Holdings Corporation) Course: Standard Heater: Strong

[0067] For each of the samples, both the sample after the aforementioned ink drying process (hereinafter referred to as the "color printing + white printing" sample) and the sample after the white printing process without the aforementioned color printing process, followed by the aforementioned ink drying process (hereinafter referred to as the "white printing" sample), the image-forming area was observed at 20x magnification using an optical microscope (Keyence Corporation, model number: VHX-7000). The percentage of uncoated area (the proportion of area without ink) in the observation field was calculated using the image recognition function of the optical microscope, and the coating retention rate was calculated using the following formula (1): Coating retention rate (%) = 100 - Percentage of uncoated area (%) ... (1)

[0068] From the calculated coating retention rate, the change in coating retention rate was determined using the following formula (2), and this was used as an index for evaluating wash fastness. Change in coating retention rate (%) = Coating retention rate of the "color printing + white printing" sample - Coating retention rate of the "white printing" sample ... (2)

[0069] Observation and image recognition using an optical microscope were performed under the following conditions: • Illumination settings: Ring illumination (setting value 7, transmitted illumination 0) • Automatic area measurement function extraction method: Brightness (standard) Brightness threshold range: -30 to 0 Brightness uniformity processing: None

[0070] (c) Color Increase Rate The L* values ​​of the image-forming areas were measured for the aforementioned "color printing + white printing" sample and the aforementioned "white printing" sample using a CIE1976 L*a*b* color space scale colorimeter (X-Rite PANTONE, part number: X-Rite eXact). From the measured values, the color increase rate ΔL was calculated using the following formula (3): ΔL = L1* - L2* ... (3) L1*: L* value of the "color printing + white printing" sample L2*: L* value of the "white printing" sample

[0071] (d) Uniformity of hue of white ink printed surface For the aforementioned "color printing + white printing" sample and "white printing" sample, the a* and b* values ​​of the image-forming area were measured using a CIE1976L*a*b* color space scale colorimeter (X-Rite PANTONE, part number: X-Rite eXact). From the measured values, the color difference (ΔE) was calculated using the following formula (4), and the color difference (ΔE) was used as the criterion for judging the uniformity of hue of the white ink printed surface. Color difference (ΔE) = {(a1* - a2*)² + (b1* - b2*)²}¹ / ² ... (4) a1*: a* value of the "white printing" sample a2*: a* value of the "color printing + white printing" sample b1*: b* value of the "white printing" sample b2*: b* value of the "color printing + white printing" sample

[0072] The evaluation results for Examples 1 to 19 and Comparative Examples 1 to 4 are shown in Table 1.

[0073]

[0074] As shown in Table 1, Examples 1 to 19 showed improved wash fastness compared to the comparative example in which the same amount of white ink was applied without the application of color ink. In particular, Examples 2 to 4, 6 to 8, 10 to 12, and 14 to 19, in which 3.7 mg / cm2 or more of color ink was applied, showed a significant improvement in wash fastness. Furthermore, Examples 2 to 4, in which 1.5 times or more the amount of color ink as white ink was applied, showed an even greater improvement in wash fastness. Examples 1 to 16, in which a color ink layer with a color difference of 12 or less from the fabric color was formed, showed good hue uniformity of the white ink printed surface. In addition, Examples 1 to 13, in which a color ink layer with a color difference of 6 or less from the fabric color was formed, showed particularly good hue uniformity of the white ink printed surface.

[0075] All or part of this disclosure may also be described as follows, but is not limited to: (Note 1) An image forming apparatus comprising: a color head for ejecting color ink containing a pigment and a resin; a white head for ejecting white ink containing a pigment and a resin; and a control unit, wherein the control unit ejects the color ink from the color head onto a fabric, and ejects the white ink from the white head onto the area where the color ink has been ejected. (Note 2) The image forming apparatus according to Note 1, wherein the control unit ejects 3.7 mg / cm² or more of the color ink from the color head. (Note 3) The image forming apparatus according to Note 2, wherein the control unit ejects 1.5 times or more the amount of the color ink compared to the white ink from the color head. (Note 4) The image forming apparatus according to any one of Notes 1 to 3, wherein the control unit ejects the color ink from the color head to form a color ink layer with a color difference of 12 or less from the color of the fabric. (Note 5) The image forming apparatus according to Note 4, wherein the control unit ejects the color ink from the color head to form a color ink layer having a color difference of 6 or less from the color of the fabric. (Note 6) The image forming apparatus according to any one of Notes 1 to 5, wherein the control unit further ejects the color ink from the color head to at least a portion of the area where the white ink has been ejected. (Note 9) An image forming method comprising a control step, wherein the control step ejects color ink containing pigment and resin from the color head onto the fabric, and ejects white ink containing pigment and resin from the white head onto the area where the color ink has been ejected. (Note 10) An image forming apparatus comprising a color head for ejecting color ink containing pigment and resin, and a white head for ejecting white ink containing pigment and resin, wherein the computer of the image forming apparatus is made to execute a control procedure, the control procedure being characterized by: ejecting the color ink from the color head onto the fabric, and ejecting the white ink from the white head onto the area where the color ink has been ejected.

[0076] As described above, the image forming apparatus, image forming method, and image forming program of this disclosure can improve wash fastness even when representing grayscale on a fabric.

[0077] 1. Image forming apparatus 2. Ink set housing 3. Ink ejection unit 4. Heating unit 5. Control unit 6. Opening 7. Display device 8. Button 9. Housing 10. Opening

Claims

1. An image forming apparatus comprising: a color head for ejecting color ink containing pigment and resin; a white head for ejecting white ink containing pigment and resin; and a control unit, wherein the control unit causes the color ink to be ejected from the color head onto a fabric, and causes the white ink to be ejected from the white head onto the area where the color ink has been ejected.

2. The image forming apparatus according to claim 1, wherein the control unit ejects 3.7 mg / cm² or more of the color ink from the color head.

3. The image forming apparatus according to claim 2, wherein the control unit discharges 1.5 times or more the amount of the color ink from the color head.

4. The image forming apparatus according to any one of claims 1 to 3, wherein the control unit ejects the color ink from the color head to form a color ink layer having a color difference of 12 or less from the color of the fabric.

5. The image forming apparatus according to claim 4, wherein the control unit ejects the color ink from the color head to form a color ink layer with a color difference of 6 or less from the color of the fabric.

6. The image forming apparatus according to any one of claims 1 to 3, wherein the control unit further causes the color ink to be ejected from the color head to at least a portion of the area where the white ink has been ejected.

7. An image forming method comprising a control step, the control step being characterized by: discharging a color ink containing pigment and resin from a color head onto a fabric; and discharging a white ink containing pigment and resin from a white head onto the area where the color ink has been dispensed.

8. An image forming program comprising an image forming apparatus having a color head for ejecting color ink containing pigment and resin, and a white head for ejecting white ink containing pigment and resin, wherein the computer of the image forming apparatus is instructed to execute a control procedure, the control procedure being characterized by: ejecting the color ink from the color head onto a fabric, and ejecting the white ink from the white head onto the area where the color ink has been ejected.

Images