JP6997965B2 - Image forming device - Google Patents

Description

The present invention relates to an image forming apparatus.

Inkjet printers have advantages such as low noise, low running cost, and easy color printing, and are widely used as digital signal output devices.
In recent years, low-non-absorbent recording media such as coated paper and plastic films have been used as printed matter to which inkjet is applied, and inks for that purpose have been developed.

However, when inkjet printing is performed on these low / non-absorbent recording media, there is a problem that the ink fixability is poor because permeation drying does not occur. In order to deal with such a problem, a technique for increasing the resin content in the ink is known.

Further, in a liquid ejection device typified by an inkjet printer, foreign matter on the nozzle forming surface causes problems such as ejection failure, so it is necessary to periodically clean the nozzle forming surface. In particular, in the ink containing a large amount of resin as described above, foreign matter is likely to be generated on the nozzle forming surface. As a wiping member used for cleaning the nozzle forming surface, a method of cleaning by combining a sheet-shaped wiping member typified by a non-woven fabric or a woven cloth is already known.

Patent Document 1 describes a wiping member that prevents deterioration of the water-repellent film on the nozzle-forming surface. This wiping member is composed of a first layer that abuts on the nozzle forming surface and a second layer that is provided on the side opposite to the nozzle forming surface with respect to the first layer, and is a first layer that abuts on the nozzle forming surface. The dispersion medium of the droplets on the nozzle forming surface is guided to the second layer by capillarity and absorbed, and the dispersoid is captured in the voids of the first layer. As a result, the dispersoid is not sandwiched between the nozzle forming surface and the wiping member and wiped, so that deterioration of the water repellent film on the nozzle forming surface can be prevented.

However, in the conventional cleaning using a wiping member, the wiping property of the fixed ink formed by drying the ink adhering to the nozzle forming surface is poor, and the water repellent film on the nozzle forming surface due to an increase in the number of wiping times or an increase in wiping pressure. There was a problem of deterioration. In particular, in the case of ink containing a large amount of resin in order to improve the fixability, fixed ink is likely to be generated and the wiping property is poor.
An object of the present invention is to provide an image forming apparatus capable of efficiently wiping the fixed ink formed on the nozzle forming surface of an inkjet head by using a wiping member even if an ink containing a large amount of resin is used. And.

The problem can be solved by using the image forming apparatus of the following (1) according to the present invention as described below.
(1) An image forming apparatus comprising a ejection device for ejecting an ink composition from a nozzle and a wiping member for wiping the ink composition adhering to the nozzle forming surface of the ejection device.
The ink composition contains 6.0% by mass or more of a resin.
The wiping member comprises at least two layers, each having a void.
When the thickness of the first layer from the side in contact with the nozzle forming surface is t1 and the total thickness of the layers other than the first layer is t2, t1 <t2 holds.
An image forming apparatus in which the porosity of the first layer is smaller than the porosity of at least one layer other than the first layer.

INDUSTRIAL APPLICABILITY The present invention provides an image forming apparatus capable of improving the fixability to a recording medium and efficiently wiping the fixed ink formed on the nozzle forming surface of an inkjet head by using a wiping member. Can be done.

FIG. 1 is a diagram illustrating an example of an image forming apparatus. FIG. 2 is a diagram illustrating an example of a configuration of a nozzle plate that is wiped by a wiping member. FIG. 3 is a diagram illustrating a schematic configuration of a cleaning unit of an image forming apparatus. FIG. 4 is a diagram schematically showing an example of a cross section of a sheet-shaped wiping member.

The present invention relates to the image forming apparatus described in (1) above, but since the following (2) to (9) are included as embodiments of the invention, these embodiments will also be described.
(2) The image forming apparatus according to (1) above, wherein the ink composition contains 7.5% by mass or more of the resin.
(3) The image forming apparatus according to (1) or (2) above, wherein the ratio of the resin to the total amount of solid content in the ink composition is 50% by mass or more.
(4) The image forming apparatus according to any one of (1) to (3) above, wherein the porosity of the first layer of the wiping member is 0.60 or more and 0.85 or less.
(5) The image forming apparatus according to any one of (1) to (4) above, wherein the porosity of the first layer of the wiping member is 0.75 or more and 0.80 or less.
(6) The image formation according to any one of (1) to (5) above, wherein the porosity of at least one layer other than the first layer of the wiping member is 0.80 or more and 0.99 or less. Device.
(7) The image forming apparatus according to any one of (1) to (6) above, wherein at least the first layer of the wiping member is made of a non-woven fabric.
(8) The image forming apparatus according to any one of (1) to (7) above, wherein the wiping member has a thickness of 0.1 mm or more and 3 mm or less.
(9) The image forming apparatus according to any one of (1) to (8) above, wherein the resin is a polyurethane resin.

The present invention relates to an image forming apparatus having an ink composition (hereinafter, also referred to as ink) and a wiping member for wiping a nozzle forming surface of an inkjet head, and has the following features.
-The ink composition contains 6.0% by mass or more of the resin.
-The wiping member shall include at least two layers, each of which has a void.
-T1 <t2 holds when the thickness of the first layer from the nozzle forming surface side is t1 and the total thickness of the layers other than the first layer is t2.
-The porosity of the first layer is smaller than the porosity of at least one layer other than the first layer.

First, an image forming apparatus using the wiping member of the present invention will be described.
The image forming apparatus of the present invention has a ejection device for ejecting an ink composition from a nozzle, and a wiping member for wiping the ink composition adhering to the nozzle forming surface of the ejection device.
In the ejection device, the ink ejection head uses a piezoelectric element as a pressure generating means for pressurizing the ink in the ink flow path, and the vibrating plate forming the wall surface of the ink flow path is deformed to change the volume in the ink flow path. A so-called piezo type that discharges ink droplets, or a so-called thermal type that heats ink in the ink flow path using a heat generating resistor to generate bubbles, vibration that forms the wall surface of the ink flow path. An electrostatic type that changes the volume inside the ink flow path and ejects ink droplets by arranging the plate and the electrode facing each other and deforming the vibrating plate by the electrostatic force generated between the vibrating plate and the electrode. Any of the ink ejection heads can be mounted.
Further, in the present invention, the ink may be stored and used in an ink storage container such as an ink cartridge.

The one shown in FIG. 1 is an example of the image forming apparatus, and is provided with a serial type droplet ejection device. This image forming apparatus will be described with reference to FIGS. 1 and 2.
The carriage 3 is movably held by the main guide member 1 and the slave guide members that are laid horizontally on the left and right side plates. Then, the carriage 3 is reciprocated by the main scanning motor 5 in the main scanning direction (carriage moving direction) via the timing belt 8 bridged between the drive pulley 6 and the driven pulley 7.

The carriage 3 is equipped with recording heads 4a and 4b (referred to as "recording head 4" when not distinguished) composed of a liquid discharge head. The recording head 4 ejects ink droplets of each color of yellow (Y), cyan (C), magenta (M), and black (K), for example. Further, the recording head 4 has a nozzle 4n composed of a plurality of nozzles arranged in a sub-scanning direction orthogonal to the main scanning direction, and is mounted with the drop ejection direction facing downward.

As shown in FIG. 2, the recording head 4 has two nozzle rows Na and Nb in which a plurality of nozzles 4n are arranged.
As the liquid discharge head constituting the recording head 4, for example, a piezoelectric actuator such as a piezoelectric element or a thermal actuator that utilizes a phase change due to boiling of a liquid film using an electric heat conversion element such as a heat generating resistor can be used. ..

On the other hand, in order to transport the paper 10, the transport belt 12 is provided as a transport means for electrostatically adsorbing the paper and transporting the paper at a position facing the recording head 4. The transport belt 12 is an endless belt and is hung between the transport roller 13 and the tension roller 14.

Then, the transport belt 12 orbits in the sub-scanning direction by rotationally driving the transport roller 13 via the timing belt 17 and the timing pulley 18 by the sub-scanning motor 16. The transport belt 12 is charged (charged) by a charging roller while moving around.

Further, on one side of the carriage 3 in the main scanning direction, a maintenance / recovery mechanism 20 for maintaining / recovering the recording head 4 is arranged on the side of the transport belt 12, and on the other side, the recording head 4 is arranged on the side of the transport belt 12. Empty discharge receivers 21 that perform empty discharge from the air are arranged.
The maintenance / recovery mechanism 20 includes, for example, a cap member 20a that caps the nozzle forming surface (the surface on which the nozzle is formed) of the recording head 4, a mechanism 20b that wipes the nozzle forming surface, and an empty ejection that ejects droplets that do not contribute to image formation. It is composed of receivers and the like.

Further, an encoder scale 23 forming a predetermined pattern is attached between the plates on both sides along the main scanning direction of the carriage 3, and the carriage 3 is an encoder sensor 24 composed of a transmissive photo sensor that reads the pattern of the encoder scale 23. Is provided. These encoder scales 23 and encoder sensors 24 constitute a linear encoder (main scanning encoder) that detects the movement of the carriage 3.

Further, a chord wheel 25 is attached to the shaft of the transport roller 13, and an encoder sensor 26 composed of a transmissive photo sensor for detecting a pattern formed on the chord wheel 25 is provided. These code wheels 25 and an encoder sensor 26 constitute a rotary encoder (secondary scanning encoder) that detects the movement amount and movement position of the transfer belt 12.

In this image forming apparatus configured in this way, the paper 10 is fed from the paper feed tray onto the charged transport belt 12 and is adsorbed, and the paper 10 is conveyed in the sub-scanning direction by the circumferential movement of the transport belt 12. To.
Therefore, by driving the recording head 4 in response to the image signal while moving the carriage 3 in the main scanning direction, ink droplets are ejected onto the stopped paper 10 to record one line. Then, after transporting a predetermined amount of the paper 10, the next line is recorded.
When the recording end signal or the signal that the rear end of the paper 10 reaches the recording area is received, the recording operation is ended and the paper 10 is discharged to the paper ejection tray.

When cleaning the recording head 4, the carriage 3 is moved to the maintenance / recovery mechanism 20 while waiting for printing (recording), and the maintenance / recovery mechanism 20 cleans the carriage 3. Further, the recording head 4 may not move, but the maintenance / recovery mechanism 20 may move to clean the head.
The recording head 4 shown in FIG. 1 has two nozzle rows Na and Nb in which a plurality of nozzles 4n are arranged, respectively, as shown in FIG. One nozzle row Na of the recording head 4a ejects a black (K) droplet, and the other nozzle row Nb ejects a cyan (C) droplet. One nozzle row Na of the recording head 4b ejects magenta (M) droplets, and the other nozzle row Nb ejects yellow (Y) droplets.

As shown in FIG. 3, the mechanism 20b for wiping the nozzle forming surface mainly presses the sheet-shaped wiping member 320, the roller 410 for sending out the sheet-shaped wiping member, and the sent out wiping member 320 against the nozzle forming surface. It is composed of a pressing roller 400 and a winding roller 420 for collecting the wiping member 320 used for wiping. Further, in addition to the sheet-shaped wiping member, a rubber blade or the like for wiping the nozzle forming surface may be provided. The pressing roller 400 can adjust the pressing force by adjusting the distance between the cleaning portion and the nozzle forming surface by using a spring. The pressing member is not limited to the roller, and may be a fixed resin or rubber member. When a rubber blade or the like is provided, a mechanism for bringing the rubber blade or the like into contact with the sheet-shaped wiping member may be provided so that the sheet-shaped wiping member has a cleaning function such as the rubber blade.

After applying a certain amount of cleaning liquid to the wiping member, the cleaning unit and the head move relatively while the wiping member is pressed against the nozzle forming surface to wipe off the foreign matter 500 adhering to the nozzle forming surface. The foreign matter 500 adhering to the nozzle forming surface includes mist ink generated when ink is ejected from the nozzle, ink adhering when ink is sucked from the nozzle for cleaning or the like, mist ink, and ink adhering to a cap member. Examples include fixed ink dried on the nozzle forming surface, paper dust generated from the printed matter, and the like. The cleaning liquid may be contained in the wiping member in advance. Further, depending on the sequence, it may be wiped without applying the cleaning liquid. In particular, when it is assumed that the ink is dried and stuck on the nozzle forming surface due to waiting for a long time, it is desirable to wipe the nozzle forming surface multiple times with a sheet-shaped wiping member containing a cleaning liquid to remove the ink. ..

FIG. 4 schematically shows an example of a cross section of the sheet-shaped wiping member 320.
The sheet-shaped wiping member 320 shown in FIG. 4 is made of a non-woven fabric and has a two-layer structure of a first layer 610 and a second layer 620 from the side in contact with the nozzle forming surface. In addition to this, for example, a three-layer structure in which a film is lined for the purpose of preventing show-through of absorbed ink and improving the strength of the wiping member, and a multi-layer structure in which a plurality of absorption layers having different absorbency are provided in the second and subsequent layers. But it's okay.

The wiping member preferably includes at least two layers each having a void, and is preferably a wiping absorbing member that wipes and absorbs ink. Examples include knitted fabrics and porous bodies. In particular, for the first layer, it is preferable to use a non-woven fabric whose thickness and porosity can be relatively easily controlled. Examples of fiber materials such as non-woven fabrics, woven fabrics, and knitted fabrics include cotton, linen, silk, pulp, nylon, vinylon, polyester, polypropylene, polyethylene, rayon, cupra, acrylic, and polylactic acid. Not only a non-woven fabric made of one type of fiber but also a non-woven fabric in which a plurality of types of fibers are mixed may be used. Examples of the porous body include polyurethane, polyolefin, PVA and the like. As a method for producing a non-woven fabric, for example, wet or dry method, spun bond, melt blown, flash spinning, etc. are used for forming the web, and spun lace, thermal bond, chemical bond, needle punch, etc. are used for bonding the web. Be done.

そして、シート状の不織布等の場合には、上記の「真密度」はシートを形成する繊維の真密度であり、「見掛の密度」はシート状の材料の目付量と厚さから「目付量÷厚さ］で求めることができる。 When the thickness of the first layer from the side in contact with the nozzle forming surface is t1 and the total thickness of the layers other than the first layer is t2, t1 <t2 holds, and the porosity of the first layer is the first. When the porosity of at least one layer other than the first layer is smaller than that of the first layer, the scraping property against the fixed ink is improved, and the wiping property of the fixed ink is improved. Here, the porosity is calculated as follows.

In the case of a sheet-shaped non-woven fabric or the like, the above-mentioned "true density" is the true density of the fibers forming the sheet, and the "apparent density" is the "weighting" from the basis weight and thickness of the sheet-shaped material. Amount ÷ thickness].

The wiping member that wipes the sticking ink has a thin thickness and a small porosity, so that the sticking ink can be easily scraped off. It cannot be retained, resulting in insufficient cleanability with a single layer. Therefore, the effect can be obtained by having a portion capable of retaining the liquid component in the layer other than the first layer and having the relationship of the present invention between the layers of the wiping member.

The porosity of the first layer is preferably 0.60 or more and 0.85 or less, and more preferably 0.75 or more and 0.80 or less. When the porosity of the first layer is 0.60 or more and 0.85 or less, the wiping property of the fixed ink can be improved, and the wiping member does not form a film, and the liquid permeability is good. Can be.
Further, the porosity of at least one layer other than the first layer is preferably 0.80 or more and 0.99 or less. When the porosity of the layers other than the first layer is within the above range, the absorbability of the liquid can be improved. By combining these first layers and layers other than the first layer, it is possible to achieve both the scraping property of the fixed ink and the absorption property of the liquid, and to improve the wiping property. At least one layer other than the first layer having a porosity of 0.80 or more and 0.99 or less is preferably the second layer. It is preferable that the porosity of the first layer is smaller than the porosity of the second layer.

The thickness of the wiping member is preferably 0.1 mm or more and 3 mm or less, and more preferably 0.2 mm or more and 0.7 mm or less. When the thickness of the wiping member is 0.1 mm or more, the saturated water absorption amount of the liquid per area of the wiping member becomes sufficient, and the ink to be wiped can be sufficiently absorbed. Further, since the thickness of the wiping member is 3 mm or less, the liquid component of the ink is suitably transferred from the first layer to the layers other than the first layer, and the liquid component is absorbed by the layers other than the first layer. The effect that can be achieved is not impaired, and the device can be miniaturized.
It is preferable that at least the first layer of the wiping member is made of a non-woven fabric. By using a non-woven fabric, the thickness and porosity can be easily set in a desired numerical range.

<Ink>
Hereinafter, the organic solvent, water, coloring material, resin, additive, etc. used for the ink will be described.

The ink composition in the present invention contains 6.0% by mass or more of a resin. By adding 6.0% by mass or more of the resin, high adhesion to the recording medium can be obtained.

<Resin>
The type of resin contained in the ink is not particularly limited and may be appropriately selected depending on the intended purpose. For example, urethane resin, polyester resin, acrylic resin, vinyl acetate resin, styrene resin, butadiene resin, etc. Examples thereof include resins, styrene-butadiene resins, vinyl chloride resins, acrylic styrene resins, and acrylic silicone resins.
Resin particles made of these resins may be used. It is possible to obtain ink by mixing resin particles with a material such as a coloring material or an organic solvent in the state of a resin emulsion in which water is used as a dispersion medium. As the resin particles, those synthesized as appropriate may be used, or commercially available products may be used. Further, these may be used alone or in combination of two or more kinds of resin particles.

Polyurethane resin is preferable as the type of resin contained in the ink.
Polyurethane resin is a reactive organism of polyisocyanate and polyol. The characteristics of the polyurethane resin are that it exhibits the performances of a soft segment made of a polyol component having a weak cohesive force and a hard segment made of a urethane bond having a strong cohesive force. The soft segment is soft and resistant to deformation of the base material such as stretching and bending. On the other hand, the hard segment has high adhesion to the base material and is excellent in wear resistance.

Examples of the type of polyurethane resin include polyether-based urethane resin, polyester-based urethane resin, polycarbonate-based urethane resin, and the like.
The type of urethane resin particles contained in the ink composition is not particularly limited and may be appropriately selected depending on the intended purpose.

It is possible to obtain a surface treatment composition by mixing resin particles made of these resins with a material such as an organic solvent in the state of a resin emulsion in which water is used as a dispersion medium. As the resin particles, those synthesized as appropriate may be used, or commercially available products may be used.

The amount of the resin added is preferably 7.5% by mass or more with respect to the total amount of the ink composition.
At 7.5% by mass or more, the resin is sufficiently adhered to the recording medium, and high fixability can be obtained even on a permeable recording medium and a low / non-absorbent recording medium.

The resin content is preferably 6.0% by mass or more and 30% by mass or less, more preferably 7.5% by mass or more and 20% by mass or less, based on the total amount of ink from the viewpoint of fixability and storage stability of the ink. preferable.

The volume average particle size of the resin particles is not particularly limited and may be appropriately selected depending on the intended purpose. However, from the viewpoint of obtaining good fixability and high image hardness, 10 nm or more and 1,000 nm or less are preferable. More than 200 nm is more preferable, and 10 nm or more and 100 nm or less is particularly preferable.
The volume average particle size can be measured using, for example, a particle size analyzer (Nanotrack Wave-UT151, manufactured by Microtrac Bell Co., Ltd.).

<Organic solvent>
The organic solvent used in the present invention is not particularly limited, and a water-soluble organic solvent can be used. Examples thereof include ethers such as polyhydric alcohols, polyhydric alcohol alkyl ethers and polyhydric alcohol aryl ethers, nitrogen-containing heterocyclic compounds, amides, amines and sulfur-containing compounds.
Specific examples of polyhydric alcohols include, for example, ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, and 1,4-butane. Diol, 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, 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-butanediol, 1,2,3-butanetriol, 2,2,4-trimethyl- Examples thereof include 1,3-pentanediol and petriol.
Examples of polyhydric alcohol alkyl ethers include ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, and propylene glycol monoethyl ether.
Examples of the polyhydric alcohol aryl ethers include ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether.
Examples of the nitrogen-containing heterocyclic compound include 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, ε-caprolactam, and γ-butyrolactone. Can be mentioned.
Examples of the amides include formamide, N-methylformamide, N, N-dimethylformamide, 3-methoxy-N, N-dimethylpropionamide, 3-butoxy-N, N-dimethylpropionamide and the like.
Examples of amines include monoethanolamine, diethanolamine, triethylamine and the like.
Examples of sulfur-containing compounds include dimethyl sulfoxide, sulfolane, and thiodiethanol.
Examples of other organic solvents include propylene carbonate and ethylene carbonate.
It is preferable to use an organic solvent having a boiling point of 250 ° C. or lower because it not only functions as a wetting agent but also has good drying properties.

As the organic solvent, a polyol compound having 8 or more carbon atoms and a glycol ether compound are also preferably used. 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 polyhydric alcohol alkyls such as ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, and propylene glycol monoethyl ether. Ethers; Examples thereof include polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether.

A polyol compound having 8 or more carbon atoms and a glycol ether compound can improve the permeability of ink when paper is used as a recording medium.

The content of the organic solvent in the ink is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 10% by mass or more and 60% by mass or less from the viewpoint of ink drying property and ejection reliability. More preferably, it is 20% by mass or more and 60% by mass or less.

<Water>
The content of water in the ink is not particularly limited and may be appropriately selected depending on the intended purpose, but from the viewpoint of ink drying property and ejection reliability, it is preferably 10% by mass or more and 90% by mass or less, and 20% by mass. % Or more and 60% by mass or less are more preferable.

<Color material>
The coloring material is not particularly limited, and pigments and dyes can be used.
As the pigment, an inorganic pigment or an organic pigment can be used. These may be used alone or in combination of two or more. Further, a mixed crystal may be used as the pigment.
As the pigment, for example, black pigment, yellow pigment, magenta pigment, cyan pigment, white pigment, green pigment, orange pigment, glossy color pigment such as gold or silver, metallic pigment and the like can be used.
As inorganic pigments, carbon black produced by known methods such as contact method, furnace method, thermal method, in addition to titanium oxide, iron oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, cadmium red, and chrome yellow. Can be used.
Examples of organic pigments include azo pigments and polycyclic pigments (for example, phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, indigo pigments, thioindigo pigments, isoindolinone pigments, quinophthalone pigments, etc.). , Dye chelate (for example, basic dye type chelate, acid dye type chelate, etc.), nitro pigment, nitroso pigment, aniline black and the like can be used. Among these pigments, those having a good affinity with a solvent are preferably used. In addition, resin hollow particles and inorganic hollow particles can also be used.
As a specific example of the pigment, for black, carbon black (CI pigment black 7) such as furnace black, lamp black, acetylene black, channel black, or copper, iron (CI pigment black 11) , Metals such as titanium oxide, and organic pigments such as aniline black (CI pigment black 1).
Further, for color, C.I. I. Pigment Yellow 1, 3, 12, 13, 14, 17, 24, 34, 35, 37, 42 (yellow iron oxide), 53, 55, 74, 81, 83, 95, 97, 98, 100, 101, 104 , 108, 109, 110, 117, 120, 138, 150, 153, 155, 180, 185, 213, C.I. I. Pigment Orange 5, 13, 16, 17, 36, 43, 51, C.I. I. Pigment Red 1, 2, 3, 5, 17, 22, 23, 31, 38, 48: 2, 48: 2 (Permanent Red 2B (Ca)), 48: 3, 48: 4, 49: 1, 52: 2, 53: 1, 57: 1 (Brilliant Carmin 6B), 60: 1, 63: 1, 63: 2, 64: 1, 81, 83, 88, 101 (Mengara), 104, 105, 106, 108 ( Cadmium Red), 112, 114, 122 (Quinacridone Magenta), 123, 146, 149, 166, 168, 170, 172, 177, 178, 179, 184, 185, 190, 193, 202, 207, 208, 209, 213, 219, 224, 254, 264, C.I. I. Pigment Violet 1 (Rhodamine Lake), 3, 5: 1, 16, 19, 23, 38, C.I. I. Pigment Blue 1, 2, 15 (phthalocyanine blue), 15: 1, 15: 2, 15: 3, 15: 4 (phthalocyanine blue), 16, 17: 1, 56, 60, 63, C.I. I. Pigment Greens 1, 4, 7, 8, 10, 17, 18, 36, etc.
The dye is not particularly limited, and acid dyes, direct dyes, reactive dyes, and basic dyes can be used, and one type may be used alone or two or more types may be used in combination.
As a dye, for example, C.I. I. Acid Yellow 17, 23, 42, 44, 79, 142, C.I. I. Acid Red 52,80,82,249,254,289, C.I. I. Acid Blue 9,45,249, C.I. I. Acid Black 1,2,24,94, C.I. I. Food Black 1, 2, C.I. I. Direct Yellow 1,12,24,33,50,55,58,86,132,142,144,173, C.I. I. Direct Red 1,4,9,80,81,225,227, C.I. I. Direct Blue 1,2,15,71,86,87,98,165,199,202, C.I. I. Dylekdo Black 19,38,51,71,154,168,171,195, C.I. I. Reactive Red 14, 32, 55, 79, 249, C.I. I. Reactive Black 3, 4, 35 can be mentioned.

The content of the coloring material in the ink is preferably 15% by mass or less from the viewpoint of good fixing property and ejection stability. More preferably, it is 10% by mass or less. The color material content of 0% by mass means that the ink can be used as a clear ink containing no color material.

As a method of dispersing the pigment to obtain an ink, a method of introducing a hydrophilic functional group into the pigment to obtain a self-dispersible pigment, a method of coating the surface of the pigment with a resin and dispersing it, and a method of dispersing using a dispersant are used. The method, etc. can be mentioned.
As a method of introducing a hydrophilic functional group into a pigment to obtain a self-dispersing pigment, for example, a method of adding a functional group such as a sulfone group or a carboxyl group to a pigment (for example, carbon) so that the pigment can be dispersed in water. Can be mentioned.
Examples of the method of coating the surface of the pigment with a resin and dispersing the pigment include a method of encapsulating the pigment in microcapsules so that the pigment can be dispersed in water. This can be rephrased as a resin-coated pigment. In this case, it is not necessary that all the pigments blended in the ink are coated with the resin, and the uncoated pigments and the partially coated pigments are dispersed in the ink as long as the effect of the present invention is not impaired. May be.
Examples of the method of dispersing using a dispersant include a method of dispersing using a known low-molecular-weight dispersant and high-molecular-weight dispersant represented by a surfactant.
As the dispersant, for example, an anionic surfactant, a cationic surfactant, an amphoteric surfactant, a nonionic surfactant and the like can be used depending on the pigment.
As the dispersant, RT-100 (nonionic surfactant) manufactured by Takemoto Oil & Fat Co., Ltd. and a naphthalene sulfonic acid Na formalin condensate can also be suitably used as the dispersant.
The dispersant may be used alone or in combination of two or more.

<Pigment dispersion>
It is possible to obtain an ink by mixing a material such as water or an organic solvent with a pigment. It is also possible to produce an ink by mixing a material such as water or an organic solvent with a pigment dispersion obtained by mixing a pigment and other water or a dispersant.
The pigment dispersion is obtained by mixing and dispersing water, a pigment, a pigment dispersant, and other components as necessary, and adjusting the particle size. It is good to use a disperser for dispersion.
The particle size of the pigment in the pigment dispersion is not particularly limited, but the maximum frequency is 20 nm or more in terms of the maximum number because the dispersion stability of the pigment is good and the image quality such as ejection stability and image density is also high. It is preferably 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 (Nanotrack Wave-UT151, manufactured by Microtrac Bell Co., Ltd.).
The content of the pigment in the pigment dispersion is not particularly limited and may be appropriately selected depending on the intended purpose, but is 0.1% by mass from the viewpoint of obtaining good ejection stability and increasing the image density. 50% by mass or more is preferable, and 0.1% by mass or more and 30% by mass or less is more preferable.
It is preferable to degas the pigment dispersion by filtering the coarse particles with a filter, a centrifuge, or the like, if necessary.

The particle size of the solid content in the ink is not particularly limited and can be appropriately selected depending on the intended purpose. From the viewpoint of improving image quality such as ejection stability and image density, the maximum frequency of the particle size of the solid content in the ink is preferably 20 nm or more and 1000 nm or less in terms of the maximum number, and more preferably 20 nm or more and 150 nm or less. The solid content includes resin particles, pigment particles, and the like. The particle size can be measured using a particle size analyzer (Nanotrack Wave-UT151, manufactured by Microtrac Bell Co., Ltd.).

<Additives>
If necessary, a surfactant, an antifoaming agent, an antiseptic / antifungal agent, a rust preventive agent, a pH adjuster and the like may be added to the ink.

<Surfactant>
As the surfactant, any of a silicone-based surfactant, a fluorine-based surfactant, an amphoteric surfactant, a nonionic surfactant, and an anionic surfactant can be used.
The silicone-based surfactant is not particularly limited and may be appropriately selected depending on the intended purpose. Of these, those that do not decompose even at high pH are preferable. Examples of the silicone-based surfactant include side chain modified polydimethylsiloxane, double-ended modified polydimethylsiloxane, single-ended modified polydimethylsiloxane, and side chain double-ended modified polydimethylsiloxane. Those having a polyoxyethylene group and a polyoxyethylene polyoxypropylene group as the modifying group are particularly preferable because they exhibit good properties as an aqueous surfactant. Further, as the silicone-based surfactant, a polyether-modified silicone-based surfactant can also be used, and examples thereof include compounds in which a polyalkylene oxide structure is introduced into the Si portion side chain of dimethylsiloxane.
Examples of the fluorine-based surfactant include a perfluoroalkyl sulfonic acid compound, a perfluoroalkyl carboxylic acid compound, a perfluoroalkyl phosphate ester compound, a perfluoroalkyl ethylene oxide adduct, and a perfluoroalkyl ether group in the side chain. Polyoxyalkylene ether polymer compounds are particularly preferred because they have low foaming properties. Examples of the perfluoroalkyl sulfonic acid compound include perfluoroalkyl sulfonic acid and perfluoroalkyl sulfonic acid salt. Examples of the perfluoroalkylcarboxylic acid compound include perfluoroalkylcarboxylic acid and perfluoroalkylcarboxylic acid salt. Examples of the polyoxyalkylene ether polymer compound having a perfluoroalkyl ether group in the side chain include a sulfate ester salt of a polyoxyalkylene ether polymer having a perfluoroalkyl ether group in the side chain and a poly having a perfluoroalkyl ether group in the side chain. Examples thereof include salts of oxyalkylene ether polymers. The counter ions of the salts in these fluorine-based surfactants include Li, Na, K, NH ₄ , NH ₃ CH ₂ CH ₂ OH, NH ₂ (CH ₂ CH ₂ OH) ₂ , and NH (CH ₂ CH ₂ OH). ₃ etc. can be mentioned.
Examples of the amphoteric tenside include laurylaminopropionate, lauryl dimethyl betaine, stearyl dimethyl betaine, and lauryl dihydroxyethyl betaine.
Examples of the nonionic surfactant include polyoxyethylene alkyl phenyl ether, polyoxyethylene alkyl ester, polyoxyethylene alkyl amine, polyoxyethylene alkyl amide, polyoxyethylene propylene block polymer, sorbitan fatty acid ester, and polyoxyethylene sorbitan. Examples thereof include a fatty acid ester and an ethylene oxide adduct of acetylene alcohol.
Examples of the anionic surfactant include polyoxyethylene alkyl ether acetate, dodecylbenzene sulfonate, lauryl salt, polyoxyethylene alkyl ether sulfate salt and the like.
These may be used alone or in combination of two or more.

（但し、一般式（Ｓ－１）式中、ｍ、ｎ、ａ、及びｂは、それぞれ独立に、整数を表わし、Ｒは、アルキレン基を表し、Ｒ’は、アルキル基を表す。）
上記のポリエーテル変性シリコーン系界面活性剤としては、市販品を用いることができ、例えば、ＫＦ－６１８、ＫＦ－６４２、ＫＦ－６４３（信越化学工業株式会社）、ＥＭＡＬＥＸ－ＳＳ－５６０２、ＳＳ－１９０６ＥＸ（日本エマルジョン株式会社）、ＦＺ－２１０５、ＦＺ－２１１８、ＦＺ－２１５４、ＦＺ－２１６１、ＦＺ－２１６２、ＦＺ－２１６３、ＦＺ－２１６４（東レ・ダウコーニング・シリコーン株式会社）、ＢＹＫ－３３、ＢＹＫ－３８７（ビックケミー株式会社）、ＴＳＦ４４４０、ＴＳＦ４４５２、ＴＳＦ４４５３（東芝シリコン株式会社）などが挙げられる。 The silicone-based surfactant is not particularly limited and may be appropriately selected depending on the intended purpose. For example, side-chain modified polydimethylsiloxane, double-ended modified polydimethylsiloxane, one-ended modified polydimethylsiloxane, side chain. Examples thereof include both-terminal modified polydimethylsiloxane, and a polyether-modified silicone-based surfactant having a polyoxyethylene group and a polyoxyethylene polyoxypropylene group as modifying groups is particularly preferable because it exhibits good properties as an aqueous surfactant. ..
As such a surfactant, an appropriately synthesized one may be used, or a commercially available product may be used. As commercially available products, for example, they can be obtained from Big Chemie Co., Ltd., Shin-Etsu Chemical Co., Ltd., Toray Dow Corning Silicone Co., Ltd., Nippon Emulsion Co., Ltd., Kyoeisha Chemical Co., Ltd., and the like.
The above-mentioned polyether-modified silicone-based surfactant is not particularly limited and may be appropriately selected depending on the intended purpose. For example, a polyalkylene oxide structure represented by the general formula (S-1) is dimethylpoly. Examples thereof include those introduced into the Si part side chain of siloxane.

(However, in the general formula (S-1), m, n, a, and b each independently represent an integer, R represents an alkylene group, and R'represents an alkyl group.)
Commercially available products can be used as the above-mentioned polyether-modified silicone-based surfactant, for example, KF-618, KF-642, KF-643 (Shinetsu Chemical Industry Co., Ltd.), EMALEX-SS-5602, SS- 1906EX (Nippon Emulsion Co., Ltd.), FZ-2105, FZ-2118, FZ-2154, FZ-2161, FZ-2162, FZ-2163, FZ-2164 (Toray Dow Corning Silicone Co., Ltd.), BYK-33, BYK-387 (Big Chemie Co., Ltd.), TSF4440, TSF4452, TSF4453 (Toshiba Silicon Co., Ltd.) and the like can be mentioned.

上記一般式（Ｆ－１）で表される化合物において、水溶性を付与するためにｍは０～１０の整数が好ましく、ｎは０～４０の整数が好ましい。

上記一般式（Ｆ－２）で表される化合物において、ＹはＨ、又はＣ_ｍＦ_２ｍ＋１でｍは１～６の整数、又はＣＨ_２ＣＨ（ＯＨ）ＣＨ_２－Ｃ_ｍＦ_２ｍ＋１でｍは４～６の整数、又はＣ_ｐＨ_２ｐ＋１でｐは１～１９の整数である。ｎは１～６の整数である。ａは４～１４の整数である。
上記のフッ素系界面活性剤としては市販品を使用してもよい。この市販品としては、例えば、サーフロンＳ－１１１、Ｓ－１１２、Ｓ－１１３、Ｓ－１２１、Ｓ－１３１、Ｓ－１３２、Ｓ－１４１、Ｓ－１４５（いずれも、旭硝子株式会社製）；フルラードＦＣ－９３、ＦＣ－９５、ＦＣ－９８、ＦＣ－１２９、ＦＣ－１３５、ＦＣ－１７０Ｃ、ＦＣ－４３０、ＦＣ－４３１（いずれも、住友スリーエム株式会社製）；メガファックＦ－４７０、Ｆ－１４０５、Ｆ－４７４（いずれも、大日本インキ化学工業株式会社製）；ゾニール（Ｚｏｎｙｌ）ＴＢＳ、ＦＳＰ、ＦＳＡ、ＦＳＮ－１００、ＦＳＮ、ＦＳＯ－１００、ＦＳＯ、ＦＳ－３００、ＵＲ、キャプストーンＦＳ－３０、ＦＳ－３１、ＦＳ－３１００、ＦＳ－３４、ＦＳ－３５（いずれも、Ｃｈｅｍｏｕｒｓ社製）；ＦＴ－１１０、ＦＴ－２５０、ＦＴ－２５１、ＦＴ－４００Ｓ、ＦＴ－１５０、ＦＴ－４００ＳＷ（いずれも、株式会社ネオス社製）、ポリフォックスＰＦ－１３６Ａ，ＰＦ－１５６Ａ、ＰＦ－１５１Ｎ、ＰＦ－１５４、ＰＦ－１５９（オムノバ社製）、ユニダインＤＳＮ－４０３Ｎ（ダイキン工業株式会社製）などが挙げられ、これらの中でも、良好な印字品質、特に発色性、紙に対する浸透性、濡れ性、均染性が著しく向上する点から、Ｃｈｅｍｏｕｒｓ社製のＦＳ－３１００、ＦＳ－３４、ＦＳ－３００、株式会社ネオス製のＦＴ－１１０、ＦＴ－２５０、ＦＴ－２５１、ＦＴ－４００Ｓ、ＦＴ－１５０、ＦＴ－４００ＳＷ、オムノバ社製のポリフォックスＰＦ－１５１Ｎ及びダイキン工業株式会社製のユニダインＤＳＮ－４０３Ｎが特に好ましい。 As the fluorine-based surfactant, a compound having 2 to 16 carbon atoms substituted with fluorine is preferable, and a compound having 4 to 16 carbon atoms substituted with fluorine is more preferable.
Examples of the fluorine-based surfactant include a perfluoroalkyl phosphate ester compound, a perfluoroalkylethylene oxide adduct, and a polyoxyalkylene ether polymer compound having a perfluoroalkyl ether group in the side chain. Among these, the polyoxyalkylene ether polymer compound having a perfluoroalkyl ether group in the side chain is preferable because it has less foaming property, and is particularly a fluorine-based compound represented by the general formula (F-1) and the general formula (F-2). Surfactants are preferred.

In the compound represented by the 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.

In the compound represented by the above general formula (F-2), Y is H or C _m F _{2 m + 1} and m is an integer of 1 to 6, or CH ₂ CH (OH) CH ₂ -C _m F _{2 m + 1} and m is An integer of 4 to 6 or an integer of C _p H _{2p + 1} and p is an integer of 1 to 19. n is an integer of 1 to 6. a is an integer of 4 to 14.
Commercially available products may be used as the above-mentioned fluorine-based surfactant. Examples of this commercially available product include Surflon S-111, S-112, S-113, S-121, S-131, S-132, S-141, and S-145 (all manufactured by Asahi Glass Co., Ltd.); Full Lard FC-93, FC-95, FC-98, FC-129, FC-135, FC-170C, FC-430, FC-431 (all manufactured by Sumitomo 3M Co., Ltd.); Megafuck F-470, F -1405, F-474 (all manufactured by Dainippon Ink and Chemicals Co., Ltd.); Zonyl TBS, FSP, FSA, FSN-100, FSN, FSO-100, FSO, FS-300, UR, Capstone FS-30, FS-31, FS-3100, FS-34, FS-35 (all manufactured by The Chemours Company); FT-110, FT-250, FT-251, FT-400S, FT-150, FT- 400SW (all manufactured by Neos Co., Ltd.), Polyfox PF-136A, PF-156A, PF-151N, PF-154, PF-159 (manufactured by Omniova), Unidyne DSN-403N (manufactured by Daikin Industries Co., Ltd.) Among these, FS-3100, FS-34, FS- of The Chemours Co., Ltd. from the viewpoint of remarkably improving good print quality, particularly color development, permeability to paper, wettability, and leveling property. 300, FT-110, FT-250, FT-251, FT-400S, FT-150, FT-400SW manufactured by Neos Co., Ltd., Polyfox PF-151N manufactured by Omninova, and Unidyne DSN-manufactured by Daikin Industries Co., Ltd. 403N is particularly preferable.

The content of the surfactant in the ink is not particularly limited and may be appropriately selected depending on the intended purpose. However, from the viewpoint of excellent wettability and ejection stability and improvement in image quality, 0.001 mass is used. % Or more and 5% by mass or less are preferable, and 0.05% by mass or more and 5% by mass or less are more preferable.

<Defoamer>
The defoaming agent is not particularly limited, and examples thereof include a silicone-based defoaming agent, a polyether-based defoaming agent, and a fatty acid ester-based defoaming agent. These may be used alone or in combination of two or more. Among these, a silicone-based defoaming agent is preferable because it has an excellent defoaming effect.

<Preservatives and fungicides>
The antiseptic and antifungal agent is not particularly limited, and examples thereof include 1,2-benzisothiazolin-3-one and the like.

<Rust inhibitor>
The rust preventive is not particularly limited, and examples thereof include acidic sulfites and sodium thiosulfate.

<pH adjuster>
The pH adjusting agent is not particularly limited as long as the pH can be adjusted to 7 or more, and examples thereof include amines such as diethanolamine and triethanolamine.

The physical characteristics of the ink are not particularly limited and may be appropriately selected depending on the intended purpose. For example, the viscosity, surface tension, pH and the like are preferably in the following ranges.
The viscosity of the ink at 25 ° C. is preferably 5 mPa · s or more and 30 mPa · s or less, preferably 5 mPa · s or more and 25 mPa · s or less, from the viewpoint of improving the print density and character quality and obtaining good ejection properties. More preferred. Here, for the viscosity, for example, a rotary viscometer (RE-80L manufactured by Toki Sangyo Co., Ltd.) can be used. As the measurement conditions, it is possible to measure at 25 ° C. with a standard cone rotor (1 ° 34'× 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. from the viewpoint that the ink is preferably 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 the metal member that comes into contact with the liquid.

This recording device can include not only a portion for ejecting ink but also a device called a pretreatment device, a posttreatment device, and the like.
As one aspect of the pretreatment apparatus and the posttreatment apparatus, it has a pretreatment liquid and a posttreatment liquid as in the case of inks such as black (K), cyan (C), magenta (M), and yellow (Y). There is an embodiment in which a liquid accommodating portion and a liquid discharge head are added, and a pretreatment liquid or a posttreatment liquid is discharged by an inkjet recording method.
As another aspect of the pretreatment device and the posttreatment device, there is a mode in which a pretreatment device and a posttreatment device by, for example, a blade coating method, a roll coating method, and a spray coating method are provided other than the inkjet recording method.

<Pretreatment liquid>
The pretreatment liquid contains a flocculant, an organic solvent, and water, and may contain a surfactant, an antifoaming agent, a pH adjuster, an antiseptic / antifungal agent, an anticorrosive agent, and the like, if necessary.
As the organic solvent, surfactant, defoaming agent, pH adjuster, antiseptic and antifungal agent, and rust preventive, the same materials as those used for ink can be used, and other materials used for known treatment liquids can be used. ..
The type of flocculant is not particularly limited, and examples thereof include water-soluble cationic polymers, acids, and polyvalent metal salts.

<Post-treatment liquid>
The post-treatment liquid is not particularly limited as long as it is possible to form a transparent layer. The post-treatment liquid is obtained by selecting and mixing organic solvents, water, resins, surfactants, defoamers, pH adjusters, antiseptic and antifungal agents, rust preventives and the like, if necessary. Further, the post-treatment liquid may be applied to the entire recording area formed on the recording medium, or may be applied only to the area where the ink image is formed.

<Recording medium>
The recording medium is not particularly limited, and plain paper, glossy paper, special paper, cloth, or the like can be used, but good image formation is possible even if a non-permeable base material is used.
The impermeable base material is a base material having a surface having a low water permeability and absorbability, and includes a material that does not open to the outside even if there are many cavities inside, and more quantitatively, A substrate having a water absorption of 10 mL / m ² or less from the start of contact to 30 msec ^1/2 in the Bristow method.
As the impermeable substrate, for example, a plastic film such as a vinyl chloride resin film, a polyethylene terephthalate (PET) film, polypropylene, polyethylene, or a polycarbonate film can be preferably used.

The recording medium is not limited to that used as a general recording medium, and wallpaper, flooring, building materials such as tiles, cloth for clothing such as T-shirts, textiles, leather and the like can be appropriately used. Further, ceramics, glass, metal, or the like can be used by adjusting the configuration of the path for transporting the recording medium.

<Recorded material>
The ink recording material of the present invention comprises an image formed by using the ink of the present invention on a recording medium.
It can be recorded by an inkjet recording device and an inkjet recording method to obtain a recorded material.

The use of the ink of the present invention is not particularly limited and may be appropriately selected depending on the intended purpose, and can be applied to, for example, printed matter, paints, coating materials, base materials and the like. Further, it can be used not only as an ink to form two-dimensional characters and images, but also as a three-dimensional modeling material for forming a three-dimensional stereoscopic image (three-dimensional model).
As the three-dimensional modeling apparatus for modeling the three-dimensional object, a known one can be used, and is not particularly limited, but for example, an apparatus provided with ink accommodating means, supply means, ejection means, drying means and the like is used. be able to. The three-dimensional model includes a three-dimensional model obtained by overcoating with ink. Further, a molded product obtained by processing a structure in which ink is applied on a base material such as a recording medium is also included. The molded product is, for example, a recorded material or structure formed in a sheet shape or a film shape, which has been subjected to molding processing such as heat stretching or punching. It is suitably used for molding after decorating the surface of electronic devices, meters of cameras, panels of operation parts, and the like.

Further, in the terms of the present invention, image formation, recording, printing, printing, etc. are all synonymous.

Recording media, media, and printed matter are all synonymous.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.

[Ink preparation]
<Adjustment of pigment dispersion>
Mix 25 g of titanium oxide STR-100W (manufactured by Sakai Chemical Industry Co., Ltd.), 5 g of pigment dispersant TEGO Dispers651 (manufactured by Ebonic), and 70 g of water, and use a bead mill (Research Lab, manufactured by Symmal Enterprises Co., Ltd.) to 0. .3 mmΦ zirconia beads were dispersed at a filling rate of 60% at 8 m / s for 5 minutes to obtain a white pigment dispersion having a volume average particle size of 285 nm.

<Preparation of urethane resin emulsion>
In a reaction vessel containing a stirrer, a reflux condenser, and a thermometer, 1,500 g of polylite OD-X-2420 (polyester polyol manufactured by DIC Corporation), 220 g of 2,2-dimethylolpropionic acid (DMPA), and 1,347 g of N-methylpyrrolidone (NMP) was charged under a nitrogen atmosphere and heated to 60 ° C. to dissolve DMPA. Next, 1,445 g of 4,4'-dicyclohexylmethane diisocyanate and 2.6 g of dibutyltin dilaurylate (catalyst) were added and heated to 90 ° C., and a urethanization reaction was carried out over 5 hours to obtain an isocyanate-terminated urethane prepolymer. Obtained. The reaction mixture was cooled to 80 ° C., and 4,340 g of triethylamine was added and mixed, and 4,340 g was extracted from the mixture and added to a mixed solution of 5,400 g of water and 15 g of triethylamine under strong stirring. Next, 1,500 g of ice was added, 626 g of a 35% by mass 2-methyl-1,5-pentanediamine aqueous solution was added, a chain extension reaction was carried out, and the solvent was distilled off so that the solid content concentration became 30% by mass. Then, the obtained resin emulsion was dispersed and treated with a paint conditioner (manufactured by Red Devil Co., Ltd., the speed can be adjusted in the range of 50 to 1,425 rpm) to obtain a urethane resin emulsion having a solid content concentration of 40.0% by mass.

<Adjustment of acrylic resin emulsion>
Boncoat CF-6140 (manufactured by DIC) was used as the acrylic resin emulsion.

<Ink adjustment method>
The ink was prepared by mixing and stirring with the formulation as shown in Table 1 (the unit of the numerical value is mass%) and filtering with a 0.5 μm polypropylene filter.
The following surfactants were used.
FS-300 (DuPont Fluorosurfactant)
Proxel LV (manufactured by Lonza Japan) was used as a preservative.

(Examples 1 to 32, comparative examples 1 to 5)
The white ink produced above and the wiping member shown in Table 2 were combined with an image forming device having an ejection device for ejecting ink from a nozzle and a wiping member, and the following evaluation was performed. As the wiping member shown in Table 2, a sheet-like material containing at least two layers each having a void was used. The fiber used in the first layer is a non-woven fabric.

[evaluation]
<Wipeability>
Using Ricoh MH5440 as an inkjet head, 0.1 ml of the white ink prepared above was dropped onto the nozzle plate of the head and then left to stand for 15 hours to prepare a nozzle plate to which the ink was fixed.
Using the wiping member and ink shown in Table 2 below, 20 μl / cm ² of a cleaning solution having the following composition was applied to the wiping member, and then the surface of the nozzle plate was wiped off. The conditions for wiping were a pressing force of 3 N and a wiping speed of 50 mm / s.
[Composition of cleaning solution]
・ 3-Methoxy-3-methyl-1-butanol (manufactured by Kuraray Co., Ltd.) 20% by mass
-Polyether-modified silicone surfactant (trade name: WET270, manufactured by Evonik Degussa Japan Co., Ltd.) 1% by mass
・ Remaining amount of ion-exchanged water

(Evaluation methods)
The nozzle plate after wiping was visually discriminated, and the number of wiping times from which the fixed ink was removed was evaluated. In the following evaluation criteria, Δ or more is a practical range, ○ is preferable, and ⊚ is even more preferable.
(Evaluation criteria)
⊚: Adhering ink on the nozzle plate was removed by cleaning 5 times.
◯: The stuck ink on the nozzle plate was removed by cleaning 7 times.
Δ: Adhering ink on the nozzle plate was removed by cleaning 10 times or less.
X: Adhering ink remains after cleaning 10 times.

<Adhesion>
Using the white ink shown in Table 2, a solid image formed on a PVC film recording medium was subjected to a grid peeling test using a cloth adhesive tape (123LW-50, manufactured by Nichiban Co., Ltd.), and the test squares were 100. The number of remaining cells was counted, and the "adhesion" to the recording medium was evaluated based on the following evaluation criteria. If the evaluation is Δ or higher, it is within a practical range, with ◯ being preferable and ⊚ being even more preferable.
(Evaluation criteria)
⊚: Number of remaining cells is 98 or more ○: Number of remaining cells is 90 or more and less than 98 Δ: Number of remaining cells is 70 or more and less than 90 ×: Number of remaining cells is less than 70

From the comparison between Examples and Comparative Example 1, it can be seen that when the amount of the resin in the ink is less than 6.0% by mass, the adhesion to the recording medium is deteriorated.
From the comparison between Examples, Comparative Examples 2, and Comparative Examples 4 to 5, it can be seen that when the porosity of the first layer is larger than the porosity of the second layer, the wiping property of the fixed ink is deteriorated.
From the comparison between Examples and Comparative Example 3, it can be seen that when the thickness of the first layer is larger than the total thickness of the layers other than the first layer, the wiping property of the fixed ink is deteriorated.

1 Main guide member 3 Carriage 4, 4a, 4b Recording head 4n Nozzle 5 Main scanning motor 6 Drive pulley 7 Driven pulley 8 Timing belt 10 Paper 12 Conveying belt 13 Conveying roller 14 Tension roller 16 Sub-scanning motor 17 Timing belt 18 Timing pulley 20 Maintenance / recovery mechanism 21 Empty discharge receiver 20a Cap member 20b Mechanism for wiping the nozzle forming surface 23 Encoder scale 24 Encoder sensor 25 Code wheel 26 Encoder sensor 320 Wiping member 400 Pushing roller 410 Roller 420 Winding roller 500 Foreign matter 610 First layer 620 Second layer Na, Nb Nozzle row

Japanese Unexamined Patent Publication No. 2014-188900

Claims (9)

An image forming apparatus comprising a ejection device for ejecting an ink composition from a nozzle and a wiping member for wiping the ink composition adhering to the nozzle forming surface of the ejection device.
The ink composition contains 6.0% by mass or more of a resin.
The wiping member comprises at least two layers, each having a void.
When the thickness of the first layer from the side in contact with the nozzle forming surface is t1 and the total thickness of the layers other than the first layer is t2, t1 <t2 holds.
An image forming apparatus in which the porosity of the first layer is smaller than the porosity of at least one layer other than the first layer. The image forming apparatus according to claim 1, wherein the ink composition contains 7.5% by mass or more of the resin. The image forming apparatus according to claim 1 or 2, wherein the ratio of the resin to the total amount of solid content in the ink composition is 50% by mass or more. The image forming apparatus according to any one of claims 1 to 3, wherein the porosity of the first layer of the wiping member is 0.60 or more and 0.85 or less. The image forming apparatus according to any one of claims 1 to 4, wherein the porosity of the first layer of the wiping member is 0.75 or more and 0.80 or less. The image forming apparatus according to any one of claims 1 to 5, wherein the porosity of at least one layer other than the first layer of the wiping member is 0.80 or more and 0.99 or less. The image forming apparatus according to any one of claims 1 to 6, wherein at least the first layer of the wiping member is made of a non-woven fabric. The image forming apparatus according to any one of claims 1 to 7, wherein the wiping member has a thickness of 0.1 mm or more and 3 mm or less. The image forming apparatus according to any one of claims 1 to 8, wherein the resin is a polyurethane resin.

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