unit

Abstract

To provide a unit that improves platen contamination occurring during printing and bleed marks appearing in a printed image caused by an increase in the amount of pretreatment liquid and white undercoat ink in DTG technology that performs printing by directly discharging aqueous pigment ink onto fabric.SOLUTION: A unit that is attachable to and detachable from a printing apparatus is provided. The unit includes a support to support a printing medium, and the support comprises a water-absorbent material.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a unit. [Background technology]

[0002] In recent years, direct-to-garment (DTG) printing, which involves ejecting aqueous pigment ink directly onto fabric, has become widely used as a printing technique using inkjet technology.

[0003] For example, in order to improve the ease of fabric setting work, a printing device has been proposed that is equipped with a cassette-type platen that includes a fabric holding member, a receiving member, and a printing means, and that allows switching from printing to heat fixing processing simply by inserting and removing the cassette while the printing material (T-shirt) remains set (see Patent Document 1). Summary of the Invention [Problem to be solved by the invention]

[0004] SUMMARY OF THE INVENTION An object of the present invention is to provide a unit that reduces platen stains that occur during printing and bleeding marks that appear on printed images. [Means for solving the problem]

[0005] The unit of the present invention as a means for solving the problem comprises: A unit that is detachable from a printing device, The unit has a support member that supports the print medium, The support member is made of a water-absorbent material. [Effects of the Invention]

[0006] According to the present invention, it is possible to provide a unit that reduces platen stains that occur during printing and bleeding marks that appear on printed images. [Brief explanation of the drawings]

[0007] [Figure 1]FIG. 1 is a schematic explanatory diagram showing an example of a printing method in a conventional DTG printer. [Figure 2] FIG. 10 is a schematic explanatory diagram showing an example of a process by which an exudation mark occurs. [Figure 3A] 1 is an image showing an example of platen contamination that occurs in conventional DTG printing. [Figure 3B] This is an image showing an example of bleeding marks that occur in conventional DTG printing. [Figure 4] FIG. 1 is a schematic explanatory diagram showing an example of a printing method using a unit of the present invention. [Figure 5A] FIG. 2 is a schematic explanatory diagram showing an example of a coupling unit in the unit of the present invention. [Figure 5B] FIG. 2 is a schematic explanatory diagram showing an example of the structure of the pallet bottom in the unit of the present invention. [Figure 5C] FIG. 10 is a schematic explanatory diagram showing another example of the structure of the pallet bottom in the unit of the present invention. [Figure 6] 10A to 10C are schematic explanatory diagrams showing an example of a process in which the occurrence of exudation marks is suppressed by the support member in the unit of the present invention. [Figure 7A] FIG. 3 is a schematic explanatory view showing an example of the shape (slope shape) of a support member in the unit of the present invention. [Figure 7B] FIG. 3 is a schematic explanatory view showing an example of the shape (round shape) of a support member in the unit of the present invention. [Figure 8A] 10 is a schematic explanatory diagram showing an example of a method for attaching a support member to a pallet in the unit of the present invention. FIG. [Figure 8B] 10A and 10B are schematic explanatory views showing another example of a method for attaching a support member to a pallet in the unit of the present invention. [Figure 8C] FIG. 10 is a schematic explanatory diagram showing yet another example of a method for attaching a support member to a pallet in the unit of the present invention. [Figure 9A] 1 is a schematic perspective view showing an example of the structure of a DTG printer incorporating a pretreatment liquid ejection head as a printing apparatus according to the present invention. FIG. [Figure 9B]FIG. 9B is a schematic explanatory diagram showing an example of the DTG printer with a built-in pretreatment liquid ejection head shown in FIG. 9A when viewed from above. [Figure 9C] FIG. 9B is a schematic cross-sectional view of the DTG printer with the built-in pretreatment liquid ejection head of FIG. 9A, showing the stage operation in the printer. [Figure 10A] 1 is a schematic perspective view showing an example of the structure of a media cassette compatible DTG printer as a printing device according to the present invention. [Figure 10B] 10B is a schematic perspective view showing an example of how a cassette is used in the media-loaded cassette-compatible DTG printer of FIG. 10A. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0008] The typical printing method for conventional DTG printers involves applying a pretreatment liquid to the print medium, then applying the printing color ink and thermally fixing it. The pretreatment liquid is applied to the print medium to firmly fix the colorant, helping to fix inks that are difficult to fix to fabric fibers (such as white pigment ink) and to fix inks to polyester fibers, which do not fix pigment inks themselves.

[0009] When the print medium is a color other than white (black, red, blue, green, etc.), the pretreatment liquid and color printing inks tend to be used in larger amounts than when the print medium is white. This is because, when the print medium is a color other than white, a white ink layer (base layer) must be formed by applying only white ink to the print medium after applying the pretreatment liquid and before applying the color printing inks, in order to minimize the impact on the color reproducibility of the printed image. Another factor is that the white ink layer (base layer) is preferably formed thicker than the color printing ink layer to prevent the color of the print medium from showing through and affecting the color reproducibility of the printed image, and to prevent the white ink layer from peeling off due to friction or washing, since white ink is difficult to fix to some print media. As the amount of white ink used increases, the amount of pretreatment liquid applied to the print medium in advance also increases.

[0010] However, with the above-described conventional technology, there is a concern that white ink or pretreatment liquid may seep onto the backside of the print medium during printing, contaminating the platen. This is due to the increased consumption of white ink or pretreatment liquid. When the platen is contaminated with white ink or pretreatment liquid, secondary contamination may occur, such as the white ink or pretreatment liquid on the platen being retransferred and contaminating the backside of the print medium, or being sprayed onto the surface of the print medium during press fixing. While secondary contamination can be avoided by temporarily removing the print medium and cleaning the platen surface immediately after printing, this increases the labor required to clean the platen and reset the print medium, reducing productivity. Furthermore, when the printed image is heat-fixed, the solvents (e.g., glycerin, propanediol, etc.) contained in the pretreatment liquid and inks (white ink and color printing inks) spread toward the surface of the print medium as the water evaporates, causing concerns that they may bleed out and leave marks around the printed image after heating. This occurs because the boiling point of the solvent is higher than the temperature during heat fixation, so the solvent does not evaporate and remains around the printed image. The appearance of bleed-out marks can mar the product's appearance and reduce its quality.

[0011] Here, the problems of platen stains that occur during printing and bleeding marks that appear on printed images in the prior art will be described with reference to FIGS. 1 to 3B. [Figures 1 and 3] Fig. 1 is a schematic explanatory diagram showing an example of a printing method in a conventional DTG printer. Note that Fig. 1 shows an example in which the print medium is other than white. As described above, in conventional DTG printing, a pretreatment liquid, white ink, and color inks are sequentially applied to a print medium 2000 supported on a platen 1000. The pretreatment liquid is ejected from a pretreatment liquid head 3000, the white ink is ejected from a white ink head 4000, and the color inks are ejected from various heads 5000 (5000C, 5000M, 5000Y, and 5000K) corresponding to the color (see FIG. 1a). The white ink forms a white ink layer 4001, and the color inks form color ink layers 5001 corresponding to the color (see FIG. 1b). When the print medium 2000 is removed from the platen 1000, seepage ink 4002, such as the white ink and pretreatment liquid, seeps onto the platen, causing stains (see FIG. 1b'). FIG. 3A shows an example of platen staining that occurs in conventional DTG printing. Next, impermeable paper 6001 is placed on each layer, and the layers are fixed and dried using a heat press 6000 to obtain a printed image (see Figure 1c). The resulting printed image has bleeding marks 7000 around its periphery. Figure 3B shows an example of bleeding marks that occur in conventional DTG printing.

[0012] [Figure 2] Figure 2 is a schematic explanatory diagram showing an example of the process by which exudation marks occur, where Figure 2a corresponds to Figure 1b, and Figure 2b corresponds to Figure 1c. Because the image-forming area of the print medium 2000 is dominated by the pigment components of the white ink layer 4001 and the color ink layer 5001, water and solvent components 7001 diffuse toward the periphery of the image-forming area (see Figure 2a). When a heat fixing process is performed in this state, the print medium 2000 is sealed from the top and bottom by the non-penetrating paper 6001 inserted between the print surface to prevent transfer and the lower support 6002 of the heat press machine 6000. This causes water vapor to escape in the planar direction of the print medium 2000, and the solvent components 7001 also move in the planar direction. The heat fixing temperature is set lower than the solvent volatilization temperature to prevent color migration from the print medium (sublimation of the original dye that dyes the print medium, resulting in color transfer). Therefore, only water evaporates. As a result, the solvent components 7001 remain in the print medium 2000, leaving seepage marks 7000.

[0013] Normally, such platen stains need to be cleaned each time they occur. A technique has also been proposed for minimizing platen contamination caused by ink bleed-through by providing a brush-like support member on the platen to support the back of the fabric at points. However, this technique has the problem that ink bleed-through remains on the back of the fabric. Furthermore, because the brush-like support member is not strong enough to withstand the pressing pressure, the media must be removed during heat pressing, which causes further contamination due to the ink bleed-through remaining on the back of the fabric. Furthermore, no improvement in bleeding marks was observed. That is, conventional DTG printers including the one disclosed in Patent Document 1 do not take into consideration the contamination of the platen that occurs during printing and the bleeding marks that appear on the printed image, and there is room for improvement.

[0014] The unit of the present invention is a unit that is detachable from a printing device, and the unit has a support member that supports a print medium, and the support member is made of a water-absorbent material. This configuration can sufficiently resolve various concerns in the prior art. More specifically, it can realize a unit that improves platen contamination that occurs during printing and bleeding marks that appear on printed images.

[0015] The present invention will be described in detail below. The present invention is not limited to the embodiments shown below, but may be modified within the scope of what a person skilled in the art can conceive, such as other embodiments, additions, modifications, or deletions, and any embodiment is within the scope of the present invention as long as it achieves the functions and effects of the present invention.

[0016] (unit) The unit of the present invention is a unit that is detachable from a printing device, and the unit has a support member that supports a print medium, and the support member is made of a water-absorbent material. The unit may include other members as necessary. The printing device is not particularly limited as long as it is a device that prints on a print medium and can be selected appropriately depending on the purpose, and may include, for example, a printer that applies ink and a pretreatment device that applies a pretreatment liquid.

[0017] One embodiment of the unit is a pallet that is detachable from the stage of the printing device. From the viewpoint of enabling a continuous process from printing to fixing, the pallet is preferably detachable from the stage of the printing device (printer and pre-processing device) and the stage of the heat fixing device, and more preferably is placed on the stage of the printing device (printer and pre-processing device) and the stage of the heat fixing device. Another aspect of the unit is a cassette that is detachable from the printing device. From the viewpoint of being able to perform all processes from printing to fixing in one go, the cassette is preferably detachable from the printing device (printer and pre-processing device) and the heat fixing device, and more preferably insertable into the printing device (printer and pre-processing device) and the heat fixing device.

[0018] Here, one embodiment of the present invention will be described with reference to the drawings. However, the use of the present invention is not limited to these embodiments. In each drawing, the same components are given the same reference numerals, and duplicate explanations may be omitted. Furthermore, the number, position, shape, etc. of the following components are not limited to this embodiment, and the number, position, shape, etc. may be any number, position, shape, etc. that is preferable for implementing the present invention.

[0019] [Figure 4] FIG. 4 is a schematic explanatory diagram showing an example of a printing method using the unit of the present invention. The printing apparatus shown in FIG. 4a has a configuration similar to that of the DTG printer shown in FIG. 1a, except that a pallet 9000 having a support member 8000 that supports a print medium 2000 is provided on a platen 1000. A pretreatment liquid, white ink, and color inks are applied in this order to a print medium 2000 supported by a support member 8000 of a pallet 9000. The pretreatment liquid is ejected from a pretreatment liquid head 3000, the white ink is ejected from a white ink head 4000, and the color inks are ejected from various heads 5000 (5000C, 5000M, 5000Y, and 5000K) corresponding to the color (see FIG. 4a). A white ink layer 4001 is formed from the white ink, and a color ink layer 5001 corresponding to the color is formed from the color ink (see FIG. 4b). When the pallet 9000 is removed from the platen 1000 at this time, the platen contamination that occurs in printing methods using conventional DTG printers is not observed (see FIG. 4b'). Next, impermeable paper 6001 is placed on each of the formed layers, and a heat press 6000 is used to fix and dry the image, resulting in a printed image (see Figure 4c). The resulting printed image does not show any bleeding marks 7000, which were observed in printing methods using conventional DTG printers (see Figure 4d).

[0020] The pretreatment liquid head 3000, the white ink head 4000, and the various color-specific heads 5000 serving as ejection means are preferably inkjet-type, but are not particularly limited to these. For example, blade coating, gravure coating, bar coating, roll coating, dip coating, curtain coating, slide coating, die coating, spray coating, and the like can be employed.

[0021] The heating means is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include a heat press, etc. Examples of commercially available heat presses include the product name TP700A 22L (manufactured by Horizon).

[0022] The unit is not particularly limited as long as it has a support member for supporting the print medium and is detachable from the printing device, and can be appropriately selected depending on the purpose. By using a unit with this structure, it is possible to prevent contamination of the platen that occurs when printing an image. In addition, the entire printing process can be performed without the need to load or unload the print medium, improving productivity. The size, shape, material, and structure of the unit are not particularly limited and can be selected appropriately depending on the purpose, as long as they are detachable from the stage of the printing device and do not interfere with the operation of the printing device.

[0023] The unit preferably has a coupling unit that can be attached to and detached from the stage of the printing device, thereby enabling the unit to be easily attached to and detached from the printing device. The connecting unit is not particularly limited as long as it is a member that enables the unit to be attached to and detached from the stage of the printing device, and can be appropriately selected depending on the purpose, and examples thereof include magnets and hook-and-loop fasteners. [Figure 5A] FIG. 5A is a schematic explanatory view showing an example of a coupling unit in the unit of the present invention. Figure 5A shows an example in which a pallet and a platen (platen stage) are fixed together by magnets. If the platen is made of metal, a magnet 9001 can be attached to the bottom of the pallet to form a coupled unit (see Figure 5A(a)). If the platen is made of non-metal, a magnet 9001 can be attached to the bottom of the pallet and metal 9002 can be attached to the platen to form a coupled unit (see Figure 5A(b)). Alternatively, a pair of hook-and-loop fasteners 9003 can be attached to both the pallet and the platen to form a coupled unit (see Figure 5A(c)).

[0024] The unit preferably has a frame at its bottom that fits over the outer edge of the stage of the printing device. In other words, the pallet preferably has a fitting frame at its bottom that fits onto the stage of the printing device.

[0025] [Figure 5B] FIG. 5B is a schematic explanatory view showing an example of the structure of the pallet bottom in the unit of the present invention. Figure 5B shows an example in which the bottom of the pallet has a frame that fits over the outer edge of the platen stage. The area enclosed by a dotted line in Figure 5B indicates the frame. There are no particular restrictions on the size, shape, material, and structure of the frame, and they can be selected appropriately depending on the purpose, as long as they can be fitted into the platen stage.

[0026] The unit preferably has a clamping mechanism that clamps the outer edge of the stage of the printing device.

[0027] [Figure 5C] FIG. 5C is a schematic explanatory view showing another example of the structure of the pallet bottom in the unit of the present invention. Figure 5C shows an example in which the pallet has a clamping mechanism that clamps the outer edge of the stage of the printing device. The area enclosed by a dotted line in Figure 5C shows the clamping mechanism. There are no particular restrictions on the number, size, shape, material, and structure of the clamping mechanism, and they can be selected appropriately depending on the purpose.

[0028] <Supporting member> In the present invention, the support member is made of a water-absorbent material, which can prevent platen stains that occur during printing and the occurrence of bleeding marks on printed images.

[0029] [Figure 6] FIG. 6 is a schematic explanatory diagram showing an example of a process in which the support member in the unit of the present invention suppresses the occurrence of exudation marks. FIG. 6a has a similar configuration to FIG. 2a, except that a support member 8000 for supporting the print medium 2000 is provided. Because the image-forming area of the print-receiving medium 2000 is occupied by the pigment components of the white ink layer 4001 and the color ink layer 5001, water and solvent components 7001 diffuse toward the periphery of the image-forming area (see FIG. 6a). When a heat fixing process is performed in this state, the water-absorbent support member 8000 acts as an escape route (absorber) for the steam, preventing the water and solvent components 7001 from diffusing in the planar direction of the print-receiving medium 2000 (see FIG. 6b). Furthermore, because the support member 8000 absorbs the ink that seeps out from the print-receiving medium 2000, it is possible to prevent contamination of the platen.

[0030] The material of the support member is not particularly limited as long as it contains the water-absorbing material, and can be appropriately selected depending on the purpose, and may contain other materials such as pulp fiber and lime.

[0031] The absorbent material is not particularly limited and can be selected appropriately depending on the purpose. Examples include polyester fabric (absorbency: approximately 1.2 mmL / 100 g), cotton fabric (absorbency: approximately 25 mmL / 100 g), diatomaceous earth (calcined product, absorbency: approximately 100-300 mL / 100 g), volcanic rock (processed product, absorbency: approximately 150-450 mL / 100 g), and superabsorbent polymer (absorbency: approximately 20,000-100,000 mL / 100 g). Diatomaceous earth, volcanic rock, and superabsorbent polymer have significantly higher absorbency than polyester fabric (absorbency: approximately 1.2 mmL / 100 g) and cotton fabric (absorbency: approximately 25 mmL / 100 g), both of which are commonly used for T-shirts. In this specification, "absorbency" refers to the amount of water that can be absorbed per 100 g of material. In addition, polyester fabrics and cotton fabrics can have spaces formed by the knitting method, like towel cloth, so it is possible to adjust the water absorption capacity. However, taking into consideration that the spaces are crushed by a heat press machine as a heating means, it is preferable to use a material that is strong enough to withstand the crushing of spaces even when pressed, or a material whose water absorption capacity cannot be adjusted by the spaces. In addition, the pressing force of the heat press machine (for example, 4 N / cm 2 ) is preferably a material that does not affect the porous structure.

[0032] Among these, highly water-absorbent materials having a water absorption capacity of 100 mL / 100 g or more are preferred. There are no particular restrictions on the highly absorbent material, and it can be selected appropriately depending on the purpose as long as it has the above-mentioned absorbency. However, diatomaceous earth and volcanic rock are preferred, from the viewpoint that when the absorbency decreases due to repeated use of the support member, the absorbency can be restored by polishing and removing the surface layer.

[0033] The water-absorbing material may be a suitably synthesized material or a commercially available product. Examples of such commercially available products that have a water-absorbing function, although not for their original purpose, include diapers and sanitary products containing water-absorbent polymers, and water-absorbing sheets such as dog deodorant sheets (Unicharm Corporation). Among these, sheet-like products that do not have three-dimensional processed parts such as gathers or hooks are preferred.

[0034] The water-absorbent material preferably has heat resistance. In this specification, "heat resistance" refers to the property of not deforming, altering, or losing strength when heated to 230°C. Examples of deformation, alteration, and loss of strength include loss of flatness of the water-absorbent material surface due to blistering or thermal deformation, cracking, peeling, and dissolution of the water-absorbent material, and loss of water absorption. The temperature setting of 230°C for heat resistance is due to the fact that the heat resistance limit of printing media such as cotton fabric and polyester fabric is around 230°C. If the water-absorbing material has heat resistance, the print medium on which an image has been printed can be subjected to heat fixing processing without being removed from the unit, thereby reducing the number of steps and improving productivity.

[0035] The heat-resistant water-absorbent material is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include diatomaceous earth and volcanic rock.

[0036] Diatomaceous earth is a fossilized form of diatoms, a type of phytoplankton, and is composed mainly of SiO (approximately 90%), with AlO, FeO, NaO, etc. Diatomaceous earth is a porous material that has been widely used as an interior wall material, abrasive, and fireproof material. It can withstand temperatures of 1000°C or higher.

[0037] Volcanic rocks are formed when magma suddenly cools and solidifies on or near the surface of the earth, and are primarily composed of SiO2 (45% or more). Depending on the SiO2 ratio, volcanic rocks are classified into basalt (45-52% SiO2), basaltic andesite (52-57% SiO2), andesite (57-63% SiO2), dacite (63-69% SiO2), and rhyolite (69% or more SiO2). The heat-resistant temperatures are 980°C for basalt and 1000°C or higher for andesite.

[0038] In the present invention, by using such heat-resistant absorbent materials, it is possible to prevent deterioration of the support member even when heat pressing is repeated. Note that the support member may be replaced after each heat pressing operation.

[0039] The size and structure of the support member are not particularly limited and can be appropriately selected depending on the purpose.

[0040] The shape of the support member is not particularly limited and can be selected appropriately depending on the purpose, but a plate shape is preferable, and it is more preferable that the end of the support surface of the support member that supports the printing medium is sloped or rounded.

[0041] [Figures 7A to 7B] Figure 7A is a schematic diagram showing an example of the shape (sloped) of a support member in a unit of the present invention. Figure 7B is a schematic diagram showing an example of the shape (rounded) of a support member in a unit of the present invention. The area enclosed by dotted lines in Figures 7A and 7B indicates the edge of the support surface for the print medium. By making the edge of the support surface for the print medium on the support member 8000 sloped or rounded, it is possible to prevent the support member from being thermoplastically deformed and forming press marks due to the heat and stress concentration during heat pressing. This is particularly effective when the support member 8000 is made of synthetic fibers such as polyester fabric.

[0042] Taking into consideration the decrease in water absorption and thermal deterioration that may occur with repeated use, the support member is preferably a member that is detachable from the unit and can be replaced or washed. The replaceable support member is not particularly limited and can be appropriately selected depending on the purpose, and for example, an absorbent sheet made of a polymer absorbent and a nonwoven fabric can be suitably used. The molecular absorbent is also called a highly water-absorbent polymer, and is not particularly limited and can be appropriately selected depending on the purpose.

[0043] [Figures 8A to 8C] Fig. 8A is a schematic explanatory diagram showing an example of a method for attaching a support member to a pallet in a unit of the present invention. Fig. 8A shows an example in which a fitting protrusion 9001 for fitting support member 8000 is provided on the contact surface of pallet 9000 with support member 8000. Fig. 8B is a schematic explanatory diagram showing another example of a method for attaching a support member to a pallet in a unit of the present invention. Fig. 8B shows an example in which a fitting recess 9002 for fitting the support member 8000 is provided on the contact surface of the pallet 9000 with the support member 8000. Fig. 8C is a schematic explanatory diagram showing yet another example of a method for attaching a support member to a pallet in a unit of the present invention. Fig. 8C shows an example in which a support member 8001 is fixed to a pallet 9000 by a support member fixing frame 8002. This example is particularly suitable when a water-absorbent sheet is used as the water-absorbent material. According to the attachment method shown in FIGS. 8A to 8C, the support member can be easily attached to and detached from the unit, which is preferable.

[0044] As shown in FIGS. 8A and 8B, the height H of at least a part of the support member 8000 B However, the frame height H of the pallet 9000 in the unit A It is preferable that it is higher than As shown in FIG. 8C, the height H of the support member 8001 and the support member fixing frame 8002 B is the frame height H of the pallet 9000 in the unitA It is preferable that it is higher than In this specification, the "frame height H of the pallet in the unit" A " indicates the distance from the bottom of the pallet 9000 to the top surface of the pallet 9000 as shown in FIGS. 8A to 8C, and "height H of at least a part of the support member" indicates the distance from the bottom of the pallet 9000 to the top surface of the pallet 9000. B " indicates the distance from the bottom of pallet 9000 to the top surface of support member 8000 (support member 8001 or support member fixing frame 8002) as shown in FIGS. 8A to 8C. By doing so, during heat fixation, the contact surface between the heat press surface of the heat press machine (heating device) and the print medium is limited to the area of the print medium supported by the support member, so the heat press process is not performed on non-contact areas. This creates a gap that serves as an escape route for steam, preventing the periphery of the support member from being sealed, and maintaining the water absorbency of the water-absorbing material.

[0045] <Printed media> The printing medium is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include clothing made of cotton, polyester, and blends thereof. In this specification, the terms recording medium, media, and printed material are all synonymous.

[0046] <Ink> The white ink and the color ink are not particularly limited and can be appropriately selected depending on the purpose. However, inks containing an organic solvent, water, a pigment, a resin, and an additive are preferred, and may contain other components as needed. In this specification, "ink" may be simply referred to as "water-based pigment ink."

[0047] <<Organic solvents>> The organic solvent is not particularly limited and can be appropriately selected depending on the purpose, and for example, a water-soluble organic solvent can be used, such as polyhydric alcohols, polyhydric alcohol alkyl ethers, polyhydric alcohols, ethers such as aryl ethers, nitrogen-containing heterocyclic compounds, amides, amines, and sulfur-containing compounds.

[0048] Specific examples of the water-soluble organic solvent include ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 3-methyl-1,3-butanediol, triethylene glycol, polyethylene glycol, polypropylene glycol, 1,2-pentanediol, 1,3-pentanediol, 1,4-pentanediol, 2,4-pentanediol, 1,5-pentanediol, and 1,6-pentanediol. Polyhydric alcohols such as hexanediol, 1,2-hexanediol, 1,6-hexanediol, 1,3-hexanediol, 2,5-hexanediol, 1,5-hexanediol, glycerin, 1,2,6-hexanetriol, 2-ethyl-1,3-hexanediol, ethyl-1,2,4-butanetriol, 1,2,3-butanetriol, 2,2,4-trimethyl-1,3-pentanediol, and petriol, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethyl ether, ethylene glycol monobutyl ether, diethyl ether, ethylene glycol monoethyl ... Examples of the alkyl ether include polyhydric alcohol alkyl ethers such as ethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, and propylene glycol monoethyl ether; polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether; nitrogen-containing heterocyclic compounds such as 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, ε-caprolactam, and γ-butyrolactone; amides such as formamide, N-methylformamide, N,N-dimethylformamide, 3-methoxy-N,N-dimethylpropionamide, and 3-butoxy-N,N-dimethylpropionamide; amines such as monoethanolamine, diethanolamine, and triethylamine; sulfur-containing compounds such as dimethyl sulfoxide, sulfolane, and thiodiethanol; propylene carbonate; and ethylene carbonate. Among these, it is preferable to use an organic solvent having a boiling point of 250° C. or less, since it not only functions as a wetting agent but also provides good drying properties.

[0049] In addition to the above-mentioned compounds, polyol compounds having 8 or more carbon atoms and glycol ether compounds are also preferably used as the water-soluble organic solvent. Specific examples of the polyol compound having 8 or more carbon atoms include 2-ethyl-1,3-hexanediol and 2,2,4-trimethyl-1,3-pentanediol. Specific examples of the glycol ether compound include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol monomethyl ether acetate, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol mono-n-propyl ether, ethylene glycol mono-iso-propyl ether, diethylene glycol mono-iso-propyl ether, ethylene glycol mono-n-butyl ether, ethylene glycol mono-t-butyl ether, diethylene glycol mono-t-butyl ether, triethylene glycol monobutyl ether, 1-methyl-1 polyhydric alcohol alkyl ethers such as glycol ethers such as 2-methoxybutanol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol mono-t-butyl ether, propylene glycol mono-n-propyl ether, propylene glycol mono-iso-propyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol mono-n-propyl ether, and dipropylene glycol mono-iso-propyl ether; and polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether.

[0050] The content of the organic solvent is not particularly limited and can be selected appropriately depending on the purpose. From the viewpoint of the drying property and ejection reliability of the ink, the content of the organic solvent is preferably 10% by mass or more and 60% by mass or less, and more preferably 20% by mass or more and 60% by mass or less, of the total amount of the ink.

[0051] <<Wed>> The water is not particularly limited and can be appropriately selected depending on the purpose. The content of the water is not particularly limited and can be selected appropriately depending on the purpose. From the viewpoint of the drying property and ejection reliability of the ink, the content of the water is preferably 10% by mass or more and 90% by mass or less, and more preferably 20% by mass or more and 60% by mass or less, of the total amount of the ink.

[0052] <<Pigments>> The pigment is not particularly limited and can be appropriately selected depending on the purpose. For example, inorganic pigments or organic pigments can be used. These can be used alone or in combination of two or more. Mixed crystals can also be used.

[0053] Examples of the pigment that can be used include black pigments, yellow pigments, magenta pigments, cyan pigments, white pigments, green pigments, orange pigments, glossy pigments such as gold and silver pigments, and metallic pigments.

[0054] Examples of the inorganic pigment that can be used include titanium oxide, iron oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, cadmium red, and chrome yellow, as well as carbon black produced by known methods such as a contact method, a furnace method, and a thermal method. Examples of the organic pigment that can be used include azo pigments, polycyclic pigments (e.g., phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, indigo pigments, thioindigo pigments, isoindolinone pigments, quinophthalone pigments, etc.), dye chelates (e.g., basic dye chelates, acid dye chelate sugars), nitro pigments, nitroso pigments, aniline black, etc. Among these pigments, those having good affinity with the solvent are preferably used. In addition, resin hollow particles and inorganic hollow particles can also be used.

[0055] Specific examples of the pigment include the following. Examples of black pigments include carbon blacks (CI Pigment Black 7) such as furnace black, lamp black, acetylene black, and channel black; metals such as copper, iron (CI Pigment Black 11), and titanium oxide; and organic pigments such as aniline black (CI Pigment Black 1). Examples of color pigments include CI Pigment Yellow 1, CI Pigment Yellow 3, CI Pigment Yellow 12, CI Pigment Yellow 13, CI Pigment Yellow 14, CI Pigment Yellow 17, CI Pigment Yellow 24, CI Pigment Yellow 34, CI Pigment Yellow 35, CI Pigment Yellow 37, CI Pigment Yellow 42 (yellow iron oxide), CI Pigment Yellow 53, CI Pigment Yellow 55, CI Pigment Yellow 74, C CI Pigment Yellow 81, CI Pigment Yellow 83, CI Pigment Yellow 95, CI Pigment Yellow 97, CI Pigment Yellow 98, CI Pigment Yellow 100, CI Pigment Yellow 101, CI Pigment Yellow 104, CI Pigment Yellow 108, CI Pigment Yellow 109, CI Pigment Yellow 110, CI Pigment Yellow 117, CI Pigment Yellow 120, CI Pigment Yellow 138, CI Pigment Yellow 15 0, CI Pigment Yellow 153, CI Pigment Yellow 155, CI Pigment Yellow 180, CI Pigment Yellow 185, CI Pigment Yellow 213, CI Pigment Orange 5, CI Pigment Orange 13, CI Pigment Orange 16, CI Pigment Orange 17, CI Pigment Orange 36, CI Pigment Orange 43, CI Pigment Orange 51, CI Pigment Red 1, CI Pigment Red 2, CI Pigment Red 3, CI Pigment Red 4, CI Pigment Red 5, CI Pigment Red 17, CI Pigment Red 22, CI Pigment Red 23, CI Pigment Red 31, CI Pigment Red 38, CI Pigment Red 48:2, CI Pigment Red 48:3, CI Pigment Red 48:4, CI Pigment Red 49:1, CI Pigment Red 52:2, CI Pigment Red 53:1, CI Pigment Red 57:1 (Brilliant Carmine 6B), CI Pigment Red 60:1, CIPigment Red 63:1, CI Pigment Red 63:2, CI Pigment Red 64:1, CI Pigment Red 81, CI Pigment Red 83, CI Pigment Red 88, CI Pigment Red 101 (Red Foot), CI Pigment Red 104, CI Pigment Red 105, CI Pigment Red 106, CI Pigment Red 108 (Cadmium Red), CI Pigment Red 112, CI Pigment Red 114, CI Pigment Red 122 (Quinacridone Magenta) ), CI Pigment Red 123, CI Pigment Red 146, CI Pigment Red 149, CI Pigment Red 166, CI Pigment Red 168, CI Pigment Red 170, CI Pigment Red 172, CI Pigment Red 177, CI Pigment Red 178, CI Pigment Red 179, CI Pigment Red 184, CI Pigment Red 185, CI Pigment Red 190, CI Pigment Red 193, CI Pigment Red 202, CI Pigment Red Red 207, CI Pigment Red 208, CI Pigment Red 209, CI Pigment Red 213, CI Pigment Red 219, CI Pigment Red 224, CI Pigment Red 254, CI Pigment Red 264, CI Pigment Violet 1 (Rhodamine Lake), CI Pigment Violet 3, CI Pigment Violet 5:1, CI Pigment Violet 16, CI Pigment Violet 19, CI Pigment Violet 23, CI Pigment Violet 38, CI Pigment Blue 1, CI Pigment Blue 2, CI Pigment Blue 15 (Phthalocyanine Blue), CI Pigment Blue 15:1, CI Pigment Blue 15:2, CI Pigment Blue 15:3, CI Pigment Blue 15:4 (Phthalocyanine Blue), CI Pigment Blue 16, CI Pigment Blue 17:1, CI Pigment Blue 56, CI Pigment Blue 60, CI Pigment Blue 63, CI Pigment Green 1, CI Pigment Green 4, CIPigment Green 7, CI Pigment Green 8, CI Pigment Green 10, CI Pigment Green 17, CI Pigment Green 18, and CI Pigment Green 36.

[0056] The content of the pigment is preferably from 0.1% to 15% by mass, more preferably from 1% to 10% by mass, based on the total amount of the ink, from the viewpoints of improving image density, good fixability, and ejection stability.

[0057] Methods for dispersing pigments to obtain ink include (1) introducing hydrophilic functional groups into the pigment to make it a self-dispersing pigment, (2) coating the surface of the pigment with a resin to disperse it, and (3) using a dispersant to disperse it. As the method (1) of introducing a hydrophilic functional group into a pigment to make it a self-dispersible pigment, for example, a method of adding a functional group such as a sulfone group or a carboxyl group to a pigment (e.g., carbon) to make it dispersible in water can be mentioned. The method (2) of coating the surface of a pigment with a resin and dispersing it includes a method of encapsulating the pigment in microcapsules to make it dispersible in water. A pigment whose surface is coated with a resin and dispersed can be called a resin-coated pigment. When coating the surface of a pigment with a resin and dispersing it, it is not necessary for all of the pigments blended into the ink to be coated with a resin; uncoated or partially coated pigments may be dispersed in the ink as long as the effects of the present invention are not impaired. The (3) method of dispersing using a dispersant includes a method of dispersing using a known low-molecular-weight dispersant or a polymeric dispersant, such as a surfactant. Depending on the pigment, anionic surfactants, cationic surfactants, amphoteric surfactants, nonionic surfactants, etc., can be used as the dispersant. Paionin RT-100 (nonionic surfactant) manufactured by Takemoto Oil & Fat Co., Ltd. and sodium naphthalenesulfonate formalin condensate are also suitable dispersants. The dispersants may be used alone or in combination of two or more.

[0058] - Pigment dispersion - Ink can be obtained by mixing the pigment with water, an organic solvent, etc. Alternatively, ink can be produced by mixing a pigment with other ingredients such as water and a dispersant to form a pigment dispersion, and then mixing the pigment with other ingredients such as water and an organic solvent. The pigment dispersion is obtained by mixing and dispersing water, a pigment, a pigment dispersant, and optionally other components, and adjusting the particle size. A disperser is preferably used for dispersion. Furthermore, it is preferable to filter out coarse particles from the pigment dispersion using a filter, a centrifugal separator, or the like, and degas the pigment dispersion, as necessary.

[0059] The particle size of the pigment in the pigment dispersion is not particularly limited, but in terms of improving the dispersion stability of the pigment and improving the image quality such as ejection stability and image density, the maximum frequency, calculated as the maximum number, is preferably 20 nm or more and 500 nm or less, and more preferably 20 nm or more and 150 nm or less. The particle size of the pigment can be measured using a particle size analyzer (Nanotrac Wave II-UT151, manufactured by Microtrac MRB Co., Ltd.).

[0060] The content of the pigment in the pigment dispersion is not particularly limited and can be appropriately selected depending on the purpose. However, from the viewpoint of obtaining good ejection stability and increasing image density, the content of the pigment in the pigment dispersion is preferably 0.1% by mass or more and 50% by mass or less, and more preferably 0.1% by mass or more and 30% by mass or less, based on the total amount of the pigment dispersion.

[0061] <<Resin>> The resin is not particularly limited and can be appropriately selected depending on the purpose. Examples include urethane resin, polyester resin, acrylic resin, vinyl acetate resin, styrene resin, butadiene resin, styrene-butadiene resin, vinyl chloride resin, acrylic styrene resin, and acrylic silicone resin. Resin particles made of these resins may also be used. Ink can be obtained by mixing the resin particles in the form of a resin emulsion dispersed in water as a dispersion medium with materials such as a colorant and an organic solvent. The resin particles may be appropriately synthesized or commercially available. These resin particles may be used alone or in combination of two or more types of resin particles.

[0062] The volume-average particle size of the resin particles is not particularly limited and can be appropriately selected depending on the purpose, but from the viewpoint of obtaining good fixability and high image hardness, it is preferably 10 nm to 1,000 nm, more preferably 10 nm to 200 nm, and even more preferably 10 nm to 100 nm. The volume-average particle size can be measured, for example, using a particle size analyzer (Nanotrac Wave II-UT151, manufactured by Microtrac MRB Co., Ltd.).

[0063] The content of the resin is not particularly limited and can be selected appropriately depending on the purpose. From the viewpoint of fixability and storage stability of the ink, the content of the resin is preferably 1% by mass or more and 30% by mass or less, and more preferably 5% by mass or more and 20% by mass or less, of the total amount of the ink.

[0064] The particle size of the solid content in the ink is not particularly limited and can be appropriately selected depending on the purpose. However, from the viewpoint of improving ejection stability and image quality such as image density, the maximum frequency of particle sizes of the solid content in the ink, calculated as the maximum number, is preferably 20 nm to 1000 nm, more preferably 20 nm to 150 nm. The solid content includes the resin particles and the pigment particles. The particle size can be measured using a particle size analyzer (Nanotrac Wave II-UT151, manufactured by Microtrac MRB Co., Ltd.).

[0065] <<Additives>> If necessary, additives such as surfactants, antifoaming agents, antiseptic and antifungal agents, antirust agents, and pH adjusters may be added to the ink.

[0066] In addition to the surfactants described above, for example, any of silicone surfactants, fluorosurfactants, acetylene glycol surfactants, amphoteric surfactants (excluding the above), nonionic surfactants (excluding the above), and anionic surfactants (excluding the above) can be used as the surfactant.

[0067] The silicone surfactant is not particularly limited and can be appropriately selected depending on the purpose, but one that does not decompose even at high pH (pH 11 to 14) is preferred. Examples of silicone surfactants that do not decompose even at high pH (pH 11 to 14) include side-chain-modified polydimethylsiloxane, both-end-modified polydimethylsiloxane, one-end-modified polydimethylsiloxane, and side-chain both-end-modified polydimethylsiloxane. Among these, those having a polyoxyethylene group or a polyoxyethylene polyoxypropylene group as a modifying group are preferred from the viewpoints of improving hydrophilicity and increasing solubility in water.

[0068] Such surfactants may be appropriately synthesized or commercially available products, such as those available from BYK-Chemie Co., Ltd., Shin-Etsu Chemical Co., Ltd., Dow Corning Toray Silicone Co., Ltd., Nippon Emulsion Co., Ltd., and Kyoeisha Chemical Co., Ltd.

[0069] As the silicone surfactant, a polyether-modified silicone surfactant can also be used. The polyether-modified silicone surfactant is not particularly limited and can be appropriately selected depending on the purpose. For example, it may be a surfactant in which a polyalkylene oxide structure represented by the following general formula (S-1) is introduced into the Si moiety side chain of dimethylpolysiloxane.

[0070] [ka] (In the general formula (S-1), m, p, a, and b each independently represent an integer, R represents an alkylene group, and R' represents an alkyl group.)

[0071] As the polyether-modified silicone surfactant, commercially available products can be used, for example, under the trade names KF-353, KF-640, KF-642, KF-643, KF-644 (all manufactured by Shin-Etsu Chemical Co., Ltd.), EMALEX-SS-5051 (manufactured by Nihon Emulsion Co., Ltd.), BYK-345, BYK-347, BYK-348, BYK-375, BYK-377 (all manufactured by BYK-Chemie Japan K.K.). ), Silface SAG002, Silface SAG003, Silface SAG005, Silface SAG503A, Silface SAG008 (all manufactured by Nissin Chemical Industry Co., Ltd.), TEGO_Wet_KL245, TEGO_Wet_250, TEGO_Wet_260, TEGO_Wet_265, TEGO_Wet_270, TEGO_Wet_280 (all manufactured by Evonik Japan Co., Ltd.), and the like.

[0072] The fluorosurfactant is not particularly limited and can be appropriately selected depending on the purpose, but from the viewpoint of low foaming properties, perfluoroalkyl sulfonic acid compounds, perfluoroalkyl carboxylic acid compounds, perfluoroalkyl phosphate ester compounds, perfluoroalkyl ethylene oxide adducts, and polyoxyalkylene ether polymer compounds having a perfluoroalkyl ether group on the side chain are preferred. Examples of the perfluoroalkylsulfonic acid compound include perfluoroalkylsulfonic acid and perfluoroalkylsulfonic acid salts. Examples of the perfluoroalkyl carboxylic acid compound include perfluoroalkyl carboxylic acids and perfluoroalkyl carboxylates. Examples of the polyoxyalkylene ether polymer compound having a perfluoroalkyl ether group on the side chain include sulfate ester salts of polyoxyalkylene ether polymers having a perfluoroalkyl ether group on the side chain, and salts of polyoxyalkylene ether polymers having a perfluoroalkyl ether group on the side chain.

[0073] Counter ions of the salts in these fluorosurfactants include, for example, Li, Na, K, NH4, NH3CH2CH2OH, NH2(CH2CH2OH)2, and NH(CH2CH2OH)3.

[0074] Among these, fluorosurfactants represented by the following general formula (F-1) and general formula (F-2) are preferred.

[0075] [ka] In the compound represented by the above general formula (F-1), m is preferably an integer of 0 to 10, and n is preferably an integer of 0 to 40, in order to impart water solubility.

[0076] [ka] In the compound represented by the general formula (F-2), Y is H, C m F 2m+1 (m is an integer from 1 to 6), CH2CH(OH)CH2-C m F 2m+1 (m is an integer between 4 and 6), or C p H 2p+1 (p is an integer from 1 to 19). n is an integer from 1 to 6. a is an integer from 4 to 14.

[0077] The fluorosurfactant is preferably a compound having 2 to 16 fluorine-substituted carbon atoms, more preferably a compound having 4 to 16 fluorine-substituted carbon atoms.

[0078] The fluorosurfactant may be a commercially available product, for example, Surflon S-242, Surflon S-243, Surflon S-420, Surflon S-431 (all manufactured by AGC Seimi Chemical Co., Ltd.), Megafac F-251, Megafac F-430, Megafac F-444, Megafac F-477, Megafac F-552, Megafac F-553, Megafac F-554 (all manufactured by DIC Corporation), CAPSTONE FS-10, CAPSTONE FS-30, CAPSTONE FS-31, CAPSTONE FS-34, CAPSTONE FS-35, CAPSTONE FS-51, CAPSTONE FS-60, CAPSTONE FS-61, CAPSTONE FS-63, CAPSTONE FS-64, CAPSTONE FS-65, CAPSTONE FS-66, CAPSTONE FS-67, CAPSTONE FS-69, CAPSTONE FS-70, CAPSTONE FS-71, CAPSTONE FS-72, CAPSTONE FS-73, CAPSTONE FS-74, CAPSTONE FS-75, CAPSTONE FS-76, CAPSTONE FS-77, CAPSTONE FS-78, CAPSTONE FS-79, CAPSTONE FS-80, CAPSTONE FS-81, CAPSTONE FS-82, CAPSTONE FS-83, CAPSTONE FS-84, CAPSTONE FS-85, CAPSTONE FS-86, CAPSTONE FS-87, CAPSTONE FS-88, CAPSTONE FS-89, CAPSTONE FS-90, CAPSTONE FS-91, CAPSTONE FS-92, CAPSTONE FS-3100 (all manufactured by DuPont); Ftergent 212M, Ftergent 215M, Ftergent 250, Ftergent 251, Ftergent 222F, Ftergent 245F (all manufactured by Neos Corporation), Polyfox PF-136A, Polyfox PF-156A, Polyfox PF-151N (all manufactured by Kitamura Chemical Industries Co., Ltd.) etc. Among these, CAPSTONE FS-3100 and CAPSTON FS-34 manufactured by Chemours Corporation, Ftergent 250 and Ftergent 251 manufactured by Neos Corporation, and Polyfox PF-151N manufactured by Kitamura Chemical Industries Co., Ltd. are preferred in terms of achieving good print quality, particularly significant improvements in color development, paper penetration, wettability, and dye leveling.

[0079] The acetylene glycol surfactant is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include nonionic surfactants with a central acetylene group and a symmetrical structure. These surfactants are environmentally friendly as "wetting agents that do not foam easily."

[0080] The acetylene glycol surfactant may be a commercially available product. Examples of commercially available acetylene glycol surfactants include, by trade name, Surfynol 104E, Surfynol 420, Surfynol 440, Surfynol 465, Surfynol SE, Surfynol SE-F, Surfynol PSA-336, Surfynol DF110D, Surfynol DF58, Olfine E1004, Olfine E1010, Olfine E1020, Olfine PD-001, Olfine PD-002W, Olfine PD-004, Olfine PD-005, Olfine EXP.4001, Olfine EXP.4200, Olfine EXP.4123, and Olfine EXP.4300 (all manufactured by Nissin Chemical Industry Co., Ltd.).

[0081] The amphoteric surfactant is not particularly limited and can be appropriately selected depending on the purpose. Examples thereof include lauryl aminopropionate, lauryl dimethyl betaine, stearyl dimethyl betaine, and lauryl dihydroxyethyl betaine.

[0082] The nonionic surfactant is not particularly limited and can be appropriately selected depending on the purpose. Examples thereof include polyoxyethylene alkylphenyl ethers, polyoxyethylene alkyl esters, polyoxyethylene alkylamines, polyoxyethylene alkylamides, polyoxyethylene propylene block polymers, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, and ethylene oxide adducts of acetylene alcohol.

[0083] The anionic surfactant is not particularly limited and can be appropriately selected depending on the purpose. Examples thereof include polyoxyethylene alkyl ether acetates, dodecylbenzenesulfonates, laurates, and polyoxyethylene alkyl ether sulfates.

[0084] The content of the surfactant is not particularly limited and can be appropriately selected depending on the purpose. However, from the viewpoint of achieving excellent wettability and ejection stability and improving image quality, the content is preferably 0.001% by mass or more and 5% by mass or less, and more preferably 0.05% by mass or more and 5% by mass or less, relative to the total amount of the ink.

[0085] -Antifoaming agent- The surfactant used as the other component can be used as a defoaming agent. The defoaming agent is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include silicone-based defoaming agents, polyether-based defoaming agents, fatty acid ester-based defoaming agents, etc. Among these, silicone-based defoaming agents are preferred because of their excellent foam-breaking effect. These may be used alone or in combination of two or more.

[0086] - pH adjuster - The pH adjuster is not particularly limited and can be appropriately selected depending on the purpose as long as it can adjust the pH to 7 or higher, and examples thereof include amines such as diethanolamine and triethanolamine.

[0087] -Preservative and fungicidal agent- The antiseptic and antifungal agent is not particularly limited and can be appropriately selected depending on the purpose, and examples thereof include 1,2-benzisothiazolin-3-one.

[0088] -Rust inhibitor- The rust inhibitor is not particularly limited and can be appropriately selected depending on the purpose. Examples thereof include acid sulfites and sodium thiosulfate.

[0089] The content of the surfactant is not particularly limited and can be appropriately selected depending on the purpose. However, from the viewpoint of achieving excellent wettability and ejection stability and improving image quality, the content is preferably from 0.001% by mass to 5% by mass, and more preferably from 0.05% by mass to 5% by mass, relative to the total amount of the ink.

[0090] Examples of qualitative and quantitative methods for the organic solvent, resin, colorant, and other components contained in the ink include gas chromatography mass spectrometry (GC-MS), etc. Examples of measuring devices using gas chromatography mass spectrometry (GC-MS) include the GCMS-QP2020NX (manufactured by Shimadzu Corporation). The water content of the ink can be measured by general methods such as quantifying the volatile components using gas chromatography-mass spectrometry (GC-MS) or measuring mass fluctuations using thermogravimetry-differential thermal analysis (TG-DTA).

[0091] The physical properties of the ink are not particularly limited and can be appropriately selected depending on the purpose. For example, it is preferable that the viscosity, surface tension, pH, etc. are within the following ranges. The viscosity of the ink at 25°C is preferably 5 mPa·s or more and 30 mPa·s or less, and more preferably 5 mPa·s or more and 25 mPa·s or less, in order to improve print density and character quality and obtain good ejection properties. Here, viscosity can be measured using, for example, a rotational viscometer (RE85L manufactured by Toki Sangyo Co., Ltd.). Measurement conditions include 25°C, a standard cone rotor (1°34' x R24), a sample liquid volume of 1.2 mL, a rotation speed of 50 rpm, and 3 minutes. The surface tension of the ink is preferably 35 mN / m or less, and more preferably 32 mN / m or less at 25° C., in order to ensure that the ink is suitably leveled on the recording medium and the drying time of the ink is shortened. The pH of the ink is preferably 7 to 12, and more preferably 8 to 11, from the viewpoint of preventing corrosion of metal members that come into contact with the ink.

[0092] <Pretreatment liquid> The pretreatment liquid is not particularly limited and can be appropriately selected depending on the purpose. For example, it preferably contains a flocculant, an organic solvent, and water, and may also contain a surfactant, an antifoaming agent, a pH adjuster, an antiseptic / fungal agent, an antirust agent, and the like as needed. The organic solvent, surfactant, antifoaming agent, pH adjuster, antiseptic and antifungal agent, and antirust agent can be the same materials as those used in the ink, and other materials used in known treatment liquids can also be used.

[0093] The flocculant is not particularly limited and can be appropriately selected depending on the purpose. Examples thereof include water-soluble cationic polymers, acids, and polyvalent metal salts.

[0094] Here, an embodiment of a printing apparatus according to the present invention will be described with reference to the drawings, although the present invention is not limited to this embodiment.

[0095] [Figures 9A to 9C] FIG. 9A is a schematic perspective view showing an example of the structure of a DTG printer incorporating a pretreatment liquid ejection head as a printing apparatus according to the present invention. FIG. 9B is a schematic explanatory diagram showing an example of the DTG printer with a built-in pretreatment liquid ejection head shown in FIG. 9A when viewed from above. FIG. 9C is a schematic cross-sectional view of the DTG printer incorporating the pretreatment liquid ejection head of FIG. 9A, showing the stage operation in the printer. The DTG printer 1 with a built-in pretreatment liquid ejection head is a device that has a pretreatment liquid ejection carriage 9B separate from the printing ink ejection carriage 9A, and is capable of sequentially ejecting pretreatment liquid and printing an image with ink by temporarily pulling back the platen stage 3 on which the print medium is set to the back of the device and then carrying out the printing operation while transporting the platen toward the front of the device. The pretreatment liquid ejection carriage 9B and the printing ink ejection carriage 9A eject the pretreatment liquid and the printing ink while scanning in a direction perpendicular to the transport direction of the platen stage 3, using guide rods 11 as support members. The scanning / ejection control of the pretreatment liquid ejection carriage 9A and the printing ink ejection carriage 9B is performed by generating an ejection waveform in the head drive circuit 12 while the encoder sensor 21 reads the scale on an encoder sheet (not shown). In addition to the components described above, the DTG printer 1 with a built-in pretreatment liquid ejection head may also include a printer side panel 2, a stage feed unit cover (accordion sheet) 4, an operation panel 5, pretreatment liquid / ink cartridges 6, an ink ejection carriage unit cover 7, a pretreatment liquid ejection carriage unit cover 8, a printer back panel 50, and a stage feed belt 51.

[0096] [Figures 10A to 10B] FIG. 10A is a schematic perspective view showing an example of the structure of a media cassette compatible DTG printer as a printing device according to the present invention. FIG. 10B is a schematic perspective view showing an example of how the cassette is used in the media-loaded cassette compatible DTG printer of FIG. 10A. The media-loaded cassette-compatible DTG printer 80 is a device that uses print media loaded into a cassette-like unit 200. This device uses a cassette-like unit 200 instead of a plate-like platen stage like those in Figures 9A-9B, and the cassette is pulled back to the back of the device, and printing is performed on the media while the cassette is transported to the front of the device.

[0097] The unit 200 has a cassette base 201, which is a base member, and a support member 300, which supports the print medium in a flat state. The cassette base 201 has an outer periphery cover 202, which is an outer periphery cover member.

[0098] The unit 200 is provided with a convex portion 212 and a groove portion 211 that fit into the concave portion of the stage 111. The device body 100 constitutes a means for fixing the unit 200 and the stage 111 together after the unit 200 is slid and set on the stage 111 via the concave portion and the convex portion 212 of the stage 111. When the unit 200 holding the print medium on the support member 300 is to be mounted on the stage 111 of the device main body 100, the unit 200 is slid onto the stage 111 from the direction of arrow C and mounted.

[0099] As shown in Figure 10B, by preparing a pre-processing device 70 and a fixing device 60 with the same slot shape, the process can be carried out with a simple slot-in / out operation, without having to remove and re-install the print media loaded in the cassette.

[0100] The present invention includes, for example, the following aspects. <1> A unit that is detachable from a printing device, The unit has a support member that supports the print medium, The support member is a unit characterized by being made of a water-absorbent material. <2> The support member is made of a heat-resistant, water-absorbent material. <1> It is a unit described in <3> The support member is detachable from the unit. <1> or the above <2> It is a unit described in <4> The water-absorbing material includes diatomaceous earth. <1> From the above <3> The unit is any one of the units described above. <5> The water-absorbent material includes volcanic rock. <1> From the above <4> The unit is any one of the units described above. <6> The support member is an absorbent sheet made of a polymer absorbent and a nonwoven fabric. <1> From the above <5> The unit is any one of the units described above. <7> The height of at least a part of the support member is higher than the height of the frame of the unit. <1> From the above <6> The unit is any one of the units described above. <8> The edge of the support surface of the support member for supporting the print medium is sloped or rounded. <1> From the above <7> The unit is any one of the units described above. <9> a coupling unit that is detachable from the stage of the printing device; <1> From the above <8> The unit is any one of the units described above. <10> The printer has a frame at the bottom that is fitted over the outer edge of the stage of the printing device. <1> From the above <9> The unit is any one of the units described above. <11> a clamping mechanism for clamping the outer edge of the stage of the printing device; <1> From the above <10> The unit is any one of the units described above.

[0101] <1> from <11> The unit described in any one of the above can solve the problems in the prior art and achieve the object of the present invention. [Explanation of symbols]

[0102] 1000 platen 2000 Printed Media 3000 Pre-treatment liquid head 4000 White ink head 4001 White ink layer 4002 Bleeding Ink 5000 color ink head 5001 color ink layer 6000 Heat Press Machine 6001 Non-permeable paper 6002 Lower cradle 7000 seepage marks 7001 Solvent components 8000 Support Member 9000 pallets [Prior art documents] [Patent documents]

[0103] [Patent Document 1] Patent Publication No. 2021-185041

Claims

1. A unit that is detachable from a printing device, The unit has a support member that supports the print medium, The support member is made of a water-absorbent material.

2. 10. The unit of claim 1, wherein the support member is made of a heat-resistant, water-absorbent material.

3. The unit according to claim 1 or 2, wherein the support member is detachable from the unit.

4. 3. The unit of claim 1 or 2, wherein the water-absorbent material comprises diatomaceous earth.

5. 3. The unit of claim 1 or 2, wherein the absorbent material comprises volcanic rock.

6. 3. The unit according to claim 1, wherein the support member is an absorbent sheet made of a polymer absorbent and a nonwoven fabric.

7. 3. The unit according to claim 1, wherein the height of at least a portion of the support member is greater than the height of the frame of the unit.

8. The unit according to claim 1 or 2, wherein the edge of the support surface of the support member for supporting the print medium is sloped or rounded.

9. The unit according to claim 1 or 2, further comprising a coupling unit that is detachable from a stage of the printing device.

10. The unit according to claim 1 or 2, further comprising a frame at the bottom that is adapted to cover the outer edge of the stage of the printing device.

11. The unit according to claim 1 or 2, further comprising a clamping mechanism that clamps an outer edge of the stage of the printing device.

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