JP6115807B2 - Inkjet recording device - Google Patents

Description

  The present invention relates to an ink jet recording apparatus.

  Conventionally, a printing method using an ink jet recording method is performed by causing ink droplets to fly and adhere onto a recording medium such as paper. In recent years, due to innovative advances in ink jet recording technology, ink jet recording devices using ink jet recording methods have also been used in the field of high-definition image recording (image printing), which previously used photography and offset printing. ing.

  In the ink jet recording apparatus, when moisture and other volatile components contained in the ejected ink are evaporated, the viscosity of the ink increases (thickens). The thickened ink causes clogging at the nozzles and causes ink ejection failure. In recent ink-jet recording, high-definition recording is performed, so the amount of ejected ink droplets is a very small amount of several pL, the diameter of the nozzle that ejects ink is small, and the energy required for ink ejection is also small. ing. Since the nozzle diameter is small and the ink ejection energy is small, the influence of ink clogging due to nozzle clogging is large. In addition, bubbles may be mixed in the nozzles or the ink supply path, resulting in ejection failure. Furthermore, when ink jet recording is performed using paper, fabric, etc., a large amount of fibers and paper dust are generated by a paper feeding operation accompanying recording. Then, these generated substances, as well as surrounding dust and a small amount of ink droplets generated due to ejection adhere to the nozzle formation surface (hereinafter referred to as “nozzle formation surface”) of the print head that ejects ink. There are things to do. When foreign matter such as ink, paper dust, fiber, and dust adheres to the nozzle and the vicinity thereof, normal ejection of the ink is hindered.

  In order to prevent or eliminate the above-described ink thickening, bubble mixing, and ejection failure due to foreign matter adhering to the nozzle surface (nozzle forming surface), an ink jet recording apparatus having a wiper mechanism (recovery mechanism) has been proposed. Yes.

  For example, Patent Document 1 describes an ink jet recording apparatus provided with a cleaning mechanism using a wiping blade. The cited document 1 discloses that fine particles are arranged on the surface of the wiping blade so as to reduce the coefficient of friction between the wiping blade and the head and protect the nozzle surface.

  Patent Document 2 discloses an application for applying a treatment liquid to a recording head or a wiper member as an inkjet recording apparatus that can simultaneously achieve low cost, high weather resistance, high durability, and high reliability while keeping the apparatus compact. An ink jet recording apparatus comprising means is described.

JP 2006-142804 A JP 2009-101630 A

  However, when a wiping blade is used as in Patent Document 1, there is a problem that the cleaning performance is inferior when an uneven nozzle forming surface is cleaned. More specifically, when a wiping blade is used to clean an uneven nozzle forming surface composed of a nozzle plate and a nozzle plate cover, the wiping blade moves while scraping ink outward from the center of the blade. For this reason, ink can be left in the very vicinity of the nozzle, but ink is accumulated around the wiping blade. In particular, since there is a step between the nozzle plate and the nozzle plate cover, scraped ink accumulates. When this deposit grows, it interferes with the lip surface of the cap, causing a problem that it cannot be firmly capped. In addition, in the case of an ink jet recording apparatus that performs recording using an ink containing an inorganic pigment (hereinafter also referred to as “inorganic pigment-containing ink composition”), just using a treatment liquid as in Patent Document 2, There arises a problem that the inorganic pigment damages the liquid-repellent film and is inferior in cleaning properties. Further, if only the treatment liquid is used, it enters into the nozzle together with bubbles and causes the pigment to aggregate to cause ejection failure, or the liquid repellent film cannot be sufficiently protected without considering the pressing force at all. If the liquid repellent film is damaged, ink ejection becomes unstable, and problems such as dot landing are disturbed. FIG. 6A is an example of an undamaged liquid repellent film, and FIG. 6B is an example of a state in which damage is slightly seen but the discharge is not greatly affected. Is an example of a state where the liquid-repellent film is clearly damaged and the discharge is greatly affected. Under specific conditions using ink containing an inorganic pigment, the state shown in FIG. 6C may be reached by repeating the cleaning operation.

  The present invention has been made to solve at least a part of the problems described above, and is excellent in both cleaning properties and liquid repellent film storage stability when recording is performed using an inorganic pigment-containing ink composition. Another object of the present invention is to provide an ink jet recording apparatus.

  The present inventors diligently studied to solve the above problems. As a result, as a function of cleaning (wiping) the nozzle forming surface of the ink jet printer, a wiping mechanism for an absorbent member such as a cloth is provided, and the absorbent member, which is the wiping member, has an effect of allowing the inorganic pigment particles to penetrate inside. In addition, by adopting a structure in which an impregnating liquid having a predetermined surface tension is included in the absorbing member, ink mist, dust, cloth fibers, etc. adhering to the nozzle forming surface can be efficiently removed, and further inorganic The present invention was completed by finding that pigment particles can prevent the nozzle liquid repellent film from being damaged.

That is, the present invention is as follows.
[1]
A recording head having a plurality of nozzles for discharging an ink composition containing an inorganic pigment, a nozzle forming surface having discharge ports of the plurality of nozzles, and a liquid repellent film provided on the nozzle forming surface;
An absorbing member that absorbs the ink composition containing the inorganic pigment attached to the nozzle outlet and the nozzle forming surface;
A drive mechanism having a pressing member for relatively pressing the absorbing member containing an impregnating liquid and the nozzle forming surface;
The drive mechanism moves at least one of the absorbing member and the recording head relative to the other, and performs a cleaning operation for removing the ink composition adhering to the nozzle formation surface by the absorbing member. And
The surface tension of the impregnation solution Ri Der below 45 mN / m,
The content of the impregnating liquid is 30% by mass or more and 200% by mass or less with respect to 100% by mass of the absorbing member .
Inkjet recording device.
[2]
The ink jet recording apparatus according to item [1], wherein the impregnating liquid contains a penetrant.
[3]
The penetrant includes at least one selected from the group consisting of alkanediols having 5 to 8 carbon atoms, glycol ethers, acetylene glycol surfactants, siloxane surfactants, and fluorine surfactants, The inkjet recording apparatus according to item [2].
[4]
The ink jet recording apparatus according to [2] or [3], wherein the content of the penetrant in the impregnating liquid is 1.0% by mass or more and 40% by mass or less.
[5]
The ink jet recording apparatus according to any one of [1] to [4], wherein a content of the impregnating liquid is 30% by mass or more and 100% by mass or less with respect to 100% by mass of the absorbing member.
[6]
A nozzle plate cover that covers at least a part of the nozzle forming surface is provided on the nozzle forming surface,
The absorbent member is a fabric;
The inkjet recording apparatus according to any one of [1] to [5] above.
[7]
The inkjet recording apparatus according to any one of [1] to [6], wherein the absorbing member has a thickness of 0.1 mm to 3 mm.
[8]
The pressing member is covered with an elastic member,
The ink jet recording apparatus according to any one of [1] to [7], wherein the elastic member has a Shore A hardness of 10 to 60.
[9]
The ink jet recording apparatus according to any one of [1] to [8], wherein the ink composition further includes a resin emulsion.

1 is a perspective view of an ink jet recording apparatus according to an embodiment. It is a perspective view of a wiper unit. (A) is a front view of a wiper cassette, (b) is a front view of a wiper cassette with a housing omitted. It is a reference figure which shows the ink adhesion growth degree in a cleaning property test. It is drawing showing a nozzle formation surface. (A)-(c) is the optical microscope photograph of the nozzle vicinity after cleaning.

  DESCRIPTION OF EMBODIMENTS Hereinafter, a mode for carrying out the present invention (hereinafter referred to as “the present embodiment”) will be described in detail. However, the present invention is not limited to this, and various modifications can be made without departing from the gist thereof. Is possible.

[Inkjet recording apparatus]
The ink jet recording apparatus according to the present embodiment includes a plurality of nozzles for discharging an ink composition containing an inorganic pigment, a nozzle forming surface having discharge ports of the plurality of nozzles, and a liquid repellent film provided on the nozzle forming surface. And a recording head having
An absorbing member that absorbs the ink composition containing the inorganic pigment attached to the nozzle outlet and the nozzle forming surface;
A drive mechanism having a pressing member for relatively pressing the absorbing member containing an impregnating liquid and the nozzle forming surface;
The drive mechanism performs a cleaning operation of moving at least one of the absorbing member and the recording head relative to the other and removing the ink composition attached to the nozzle forming surface by the absorbing member. And
The surface tension of the impregnating liquid is 45 mN / m or less.

[1. (Device configuration)
[1-1. (Recording head)
The recording head of the present embodiment has a nozzle forming surface provided with a plurality of nozzles for discharging the inorganic pigment-containing ink composition, and has a liquid repellent film on the nozzle forming surface.

(Nozzle forming surface)
The nozzle forming surface is not particularly limited as long as a plurality of nozzles for discharging the inorganic pigment-containing ink composition are provided, and the first nozzle row in which a plurality of nozzles for discharging the inorganic pigment-containing ink composition are arranged, and others And a second nozzle row in which a plurality of nozzles for discharging an ink composition (hereinafter, also referred to as “another ink composition”) containing the above color material is arranged. In this case, the drive mechanism described below moves at least one of the absorbing member and the recording head relative to the other in the arrangement direction of the nozzles in the nozzle row. It is preferable that the second nozzle row is cleaned using a location of an absorbing member different from each other. Thereby, it is possible to prevent the second nozzle row from being cleaned at the portion of the absorbing member to which the inorganic pigment-containing ink composition of the first nozzle row is attached. Thus, it is possible to prevent the inorganic pigment that tends to deteriorate the liquid repellent film from moving to the second nozzle row and deteriorating the liquid repellent film near the second nozzle row. That is, it is possible to prevent the deterioration of the liquid repellent film from being expanded. In the cleaning operation, the second nozzle row may be cleaned after the cleaning operation of the first nozzle row, or both may be cleaned at the same time, but it is preferable to clean both from the viewpoint of cleaning efficiency.

(Liquid repellent film)
The liquid repellent film is disposed on the nozzle forming surface. The liquid repellent film is not particularly limited as long as it has liquid repellency. For example, a metal alkoxide molecular film having liquid repellency is formed, followed by drying treatment, annealing treatment, and the like. can do. The metal alkoxide molecular film may be any film having liquid repellency, but a metal alkoxide monomolecular film or liquid repellent group having a fluorine-containing long-chain polymer group (long-chain RF group) (for example, A monomolecular film of a metal acid salt having a long-chain polymer group containing fluorine) is desirable. Although it does not specifically limit as a metal alkoxide, For example, silicon, titanium, aluminum, and zirconium are generally used as the metal seed | species. Examples of the long chain RF group include a perfluoroalkyl chain and a perfluoropolyether chain. Examples of the alkoxysilane having a long chain RF group include a silane coupling agent having a long chain RF group. The liquid repellent film is not particularly limited, and for example, an SCA (silane coupling agent) film or a film described in Japanese Patent No. 4249495 can be used. A film having water repellency is called a water repellent film.

  The liquid repellent film may be formed by forming a conductive film on a substrate (nozzle plate) on which a nozzle is formed and forming the conductive film on the conductive film. (Plasma Polymerization Silicone film) may be formed and formed on this base film. Through this base film, the silicon material of the nozzle plate and the liquid repellent film can be blended.

  The liquid repellent film preferably has a thickness of 1 nm to 30 nm, more preferably has a thickness of 1 nm to 20 nm, and still more preferably has a thickness of 1 nm to 15 nm. By being in the above range, the nozzle formation surface tends to be more excellent in liquid repellency, the film deterioration is relatively slow, and the liquid repellency can be maintained for a longer period. Moreover, it is excellent in terms of cost and ease of film formation.

(Nozzle plate cover)
The nozzle formation surface is preferably provided with a nozzle plate cover that covers at least a part of the nozzle formation surface. The nozzle plate cover serves to fix the chip on the nozzle forming surface of the head formed by a combination of a plurality of nozzle chips (hereinafter simply referred to as “chips”), or the recording medium is lifted to record on the nozzles. It is provided to fulfill at least one of the roles of preventing the medium from coming into direct contact. And the said nozzle plate cover is provided in the state which protrudes from the nozzle, when it sees from a side surface by covering at least one part of a nozzle formation surface. When the nozzle plate cover is provided, the inorganic pigment-containing ink composition tends to remain at the corner (gap) between the nozzle forming surface and the nozzle plate cover protruding from the nozzle forming surface, and the remaining inorganic pigment-containing ink composition Due to solidification of the inorganic pigment or the like of the product, there may be a problem that the capping operation becomes poor due to insufficient adhesion between the cap and the nozzle surface. The problem becomes particularly noticeable depending on the type of resin contained in the ink composition. Therefore, when the absorbing member to which the impregnating liquid adheres abuts between the nozzle plate cover and the nozzle, the inorganic pigment-containing ink composition deposited in the gap can be removed, and the capping operation is stabilized. And good.

  FIG. 5 is a schematic view showing the nozzle forming surface 37 in the ink jet recording apparatus of the present embodiment. The installation pattern of the nozzle plate cover 35 on the nozzle forming surface 37 is not limited to the following. For example, as shown in FIG. 5A, a pattern in which the nozzle plate cover 35 is provided so as to surround each nozzle row 36. (A nozzle plate cover 35 is also provided between the nozzle rows 36), and a pattern in which the nozzle plate cover 35 is provided around a region where the nozzles exist so as to surround the entire nozzle as shown in FIG. 5B. (No nozzle plate cover is provided between the nozzle rows 36). In FIG. 5, a circle in the nozzle row 36 corresponds to a nozzle.

[1-2. Absorbing member
The absorbing member of the present embodiment is not particularly limited as long as it can absorb the inorganic pigment-containing ink composition attached to the nozzle outlet and the nozzle forming surface and can retain the impregnating liquid. Thereby, when the nozzle forming surface is cleaned, the pigment particles are absorbed into the absorbing member, and the pigment particles do not remain on the surface of the absorbing member. Therefore, the water repellent film is suppressed from being damaged by the pigment particles.

  Although it does not specifically limit as an absorption member, For example, a cloth, sponge, a pulp, etc. are mentioned. Among these, a fabric is preferable. It is easy to bend if it is a fabric, and it is easier to wipe off ink adhering to the nozzle surface, especially when a nozzle plate cover is provided. The cloth is not particularly limited, and examples thereof include those made of cupra, polyester, polyethylene, polypropylene, lyocell, rayon, and the like. At this time, it is preferable that the material of the absorbing member is a non-woven fabric (polyester) or cupra because fuzzing is small, so that it is difficult to suck ink from the nozzle and it is difficult to cause dot omission.

  The thickness of the absorbing member is preferably 0.1 mm or more and 3 mm or less. When the thickness is 0.1 mm or more, it becomes easier to hold the impregnating liquid. When the thickness is 3 mm or less, it becomes a compact absorbent member, the entire cleaning unit can be miniaturized, and the mechanical conveyance of the cleaning member becomes easier.

The areal density of the absorbing member, 0.005 g / cm ² or more 0.15 g / cm ² or less. More preferably, the 0.02 g / cm ² or more 0.13 g / cm ² or less. By being the said range, it becomes easier to hold | maintain an impregnation liquid. Further, in order to retain the impregnating liquid, it is preferable to use a non-woven fabric that can easily design the surface density and thickness of the absorbent member.

(Impregnating liquid)
The absorbing member when performing the cleaning operation contains an impregnating liquid. By containing the impregnating liquid, the pigment particles easily move from the surface of the absorbing member to the inside, and the pigment particles are less likely to remain on the surface of the absorbing member. The impregnating liquid preferably contains a penetrating agent and a humectant. Thereby, the pigment particles are easily absorbed in the absorbing member. The impregnation liquid is not particularly limited as long as it is a liquid that can move the inorganic pigment particles from the surface of the absorbing member to the inside.

  The surface tension of the impregnating liquid is 45 mN / m or less, and preferably 35 mN / m or less. When the surface tension is low, the permeability of the inorganic pigment to the absorbing member becomes good and the wiping property is improved. As a method for measuring the surface tension, a commonly used surface tension meter (for example, surface tension meter CBVP-Z manufactured by Kyowa Interface Science Co., Ltd.) is used and measured at a liquid temperature of 25 ° C. by the Wilhelmy method. A method can be exemplified.

  The content of the impregnating liquid is preferably 10% by mass or more and 200% by mass or less, preferably 10% by mass to 120% by mass or less, and 30% by mass to 100% by mass with respect to 100% by mass of the absorbing member. % Is more preferable. By being 10 mass% or more, it is easy to permeate | transmit an inorganic pigment ink to the inner side of an absorption member, and it can suppress more that a water-repellent film is damaged. Further, by being 200% by mass or less, the remaining of the impregnating liquid on the nozzle forming surface can be further suppressed, and dot omission caused by bubbles entering the nozzle together with the impregnating liquid, or the impregnating liquid itself permeates the nozzle. It is possible to further suppress dot omission due to.

  In addition, the additive (component) that can be contained in the impregnation liquid is not particularly limited, and examples thereof include a resin, an antifoaming agent, a surfactant, water, an organic solvent, and a pH adjusting agent. Each of the above components may be used alone or in combination of two or more, and the content is not particularly limited.

  When the impregnating liquid contains an antifoaming agent, it is possible to effectively prevent the impregnating liquid remaining on the nozzle forming surface after the cleaning process from foaming. The impregnating liquid may contain a large amount of an acidic moisturizing agent such as polyethylene glycol or glycerin. In this case, if the impregnating liquid contains a pH adjuster, the acidic impregnating liquid becomes an ink composition (usually pH 7. Contact with 5 or more basics) can be avoided. As a result, the ink composition can be prevented from shifting to the acidic side, and the storage stability of the ink composition is further maintained.

  In addition, the humectant that can be contained in the impregnating liquid is not particularly limited as long as it is generally usable for inks and the like. The humectant is not particularly limited, and a high-boiling humectant having a boiling point under 1 atm of preferably 180 ° C. or higher, more preferably 200 ° C. or higher can be used. When the boiling point is within the above range, the volatile components in the impregnating liquid can be prevented from volatilizing, and the inorganic pigment-containing ink composition in contact with the impregnating liquid can be reliably wetted and effectively wiped off.

  Although it does not specifically limit as a high boiling point moisturizer, For example, ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, pentamethylene glycol, trimethylene glycol, 2-butene-1,4-diol, 2-ethyl-1,3 -Hexanediol, 2-methyl-2,4-pentanediol, tripropylene glycol, polyethylene glycol, polypropylene glycol, 1,3-propylene glycol, isopropylene glycol, isobutylene glycol, glycerin, mesoerythritol, pentaerythritol, etc. It is done.

  A moisturizer may be used individually by 1 type, and 2 or more types may be mixed and used for it. The content of the humectant is preferably 10 to 100% by mass with respect to the total mass (100% by mass) of the impregnating liquid. In addition, the content of the humectant being 100% by mass with respect to the total mass of the impregnating liquid indicates that all components of the impregnating liquid are humectants.

  Of the additives that can be contained in the impregnation liquid, the penetrant will be described. Any penetrant can be used without particular limitation as long as it is generally usable for ink or the like. In a solution of 90% by weight of water and 10% by weight of the penetrant, the surface tension of the solution is 45 mN / m or less. Can be employed as a penetrant. The penetrating agent is not particularly limited, but is selected from the group consisting of, for example, alkanediols having 5 to 8 carbon atoms, glycol ethers, acetylene glycol surfactants, siloxane surfactants, and fluorine surfactants. One or more of them. The surface tension can be measured by the method described above.

  Further, the content of the penetrant in the impregnating liquid is preferably 1% by mass or more and 40% by mass or less, and more preferably 3% by mass or more and 25% by mass or less. When the content is 1% by mass or more, the wiping property tends to be superior, and when the content is 40% by mass or less, the penetrant attacks the pigment contained in the ink near the nozzle, and the dispersion stability breaks and aggregates. Can be avoided.

  The alkanediol having 5 to 8 carbon atoms is not particularly limited. For example, 1,2-pentanediol, 1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 1,2 -Heptanediol, 2-ethyl-1,3-hexanediol, 2,2-dimethyl-1,3-propanediol, 2,2-dimethyl-1,3-hexanediol and the like. C5-C8 alkanediols may be used individually by 1 type, or may use 2 or more types together.

  Although it does not specifically limit as glycol ethers, For example, ethylene glycol mono-n-butyl ether, ethylene glycol mono-t-butyl ether, diethylene glycol mono-n-butyl ether, triethylene glycol mono-n-butyl ether, diethylene glycol mono-t- Butyl ether, 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, propylene glycol mono-n-butyl ether, dipropylene glycol Mono-n-butyl ether, dipropylene glycol mono-n-propyl ether, dipropyle Glycol mono-iso-propyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, diethylene glycol ethyl methyl ether, diethylene glycol butyl methyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, dipropylene glycol dimethyl ether, dipropylene glycol diethyl ether, Tripropylene glycol dimethyl ether, ethylene glycol monoisohexyl ether, diethylene glycol monoisohexyl ether, triethylene glycol monoisohexyl ether, ethylene glycol monoisoheptyl ether, diethylene glycol monoisoheptyl ether Ter, triethylene glycol monoisoheptyl ether, ethylene glycol monoisooctyl ether, diethylene glycol monoisooctyl ether, triethylene glycol monoisooctyl ether, ethylene glycol mono-2-ethylhexyl ether, diethylene glycol mono-2-ethylhexyl ether, triethylene Examples include glycol mono-2-ethylhexyl ether, diethylene glycol mono-2-ethylpentyl ether, ethylene glycol mono-2-ethylpentyl ether, ethylene glycol mono-2-methylpentyl ether, and diethylene glycol mono-2-methylpentyl ether. Glycol ethers may be used alone or in combination of two or more.

Although it does not specifically limit as an acetylene glycol type surfactant, For example, the compound etc. which are represented by a following formula are mentioned.
[In Formula (1), 0 ≦ m + n ≦ 50, R ^{1 *} , R ^{2 *} , R ^{3 *} , and R ^{4 *} each independently represents an alkyl group (preferably an alkyl group having 1 to 6 carbon atoms). . ]

  Among the acetylene glycol surfactants represented by the formula (1), 2,4,7,9-tetramethyl-5-decyne-4,7-diol, 3,6-dimethyl-4-octyne- 3,6-diol, 3,5-dimethyl-1-hexyne-3ol and the like can be mentioned. Commercially available products may be used as the acetylene glycol surfactant represented by the formula (1), and specific examples thereof include Surfynol 82, 104, 440, 465, 485, and TG (all are Air Products). and Olfin STG, Olfin E1010 (trade name) (manufactured by Nisshin Chemical Co., Ltd.) and the like. An acetylene glycol type surfactant may be used individually by 1 type, or may use 2 or more types together.

Although it does not specifically limit as a siloxane type surfactant, For example, what is represented by following formula (2) or (3) is mentioned.
[In the formula (2), R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , and R ⁷ are each independently an alkyl group having 1 to 6 carbon atoms, preferably a methyl group. Represent. j and k each independently represent an integer of 1 or more, preferably 1 to 5, more preferably 1 to 4, and still more preferably 1 or 2, and satisfy j = k = 1 or k = j + 1. It is preferable to do. G represents an integer of 0 or more, preferably 1 to 3, and more preferably 1. Further, p and q each represent an integer of 0 or more, preferably 1 to 5. However, p + q is an integer greater than or equal to 1, Preferably p + q is 2-4. ]

As siloxane-type surfactant represented by Formula (2), R < ¹ > -R < ⁷ > represents all methyl groups, j represents 1-2, k represents 1-2, g represents 1-2. A compound in which p represents an integer of 1 to 5 and q is 0 is preferable.

[In Formula (3), R represents a hydrogen atom or a methyl group, a represents an integer of 2 to 18, m represents an integer of 0 to 50, and n represents an integer of 1 to 5. ]

  Although it does not specifically limit as a siloxane type surfactant represented by Formula (3), For example, R represents a hydrogen atom or a methyl group, a represents the integer of 7-11, m is an integer of 30-50. A compound in which n represents an integer of 3 to 5, R represents a hydrogen atom or a methyl group, a represents an integer of 9 to 13, m represents an integer of 2 to 4, and n represents 1 to 2 A compound which is an integer, R represents a hydrogen atom or a methyl group, a represents an integer of 6 to 18, m represents an integer of 0, n is an integer of 1, R represents a hydrogen atom, a Represents an integer of 2 to 5, m represents an integer of 20 to 40, and a compound in which n is an integer of 3 to 5 is preferable.

  Siloxane-based surfactants are commercially available, and commercially available products may be used. For example, Olfin PD-501 (manufactured by Nissin Chemical Industry Co., Ltd.), Olphine PD-570 (Nisshin Chemical Industries Co., Ltd.) Company-made), BYK-347 (manufactured by Big Chemie Co., Ltd.), BYK-348 (manufactured by Big Chemie Co., Ltd.) and the like can be used. The above siloxane-based surfactants may be used alone or in combination of two or more.

  As disclosed in WO2010 / 050618 and WO2011 / 007888, fluorine-based surfactants are known as solvents that exhibit good wettability with respect to low-absorbing and non-absorbing recording media. The fluorosurfactant is not particularly limited, but can be appropriately selected according to the purpose. For example, perfluoroalkyl sulfonate, perfluoroalkyl carboxylate, perfluoroalkyl phosphate, perfluoroalkylethylene. Examples thereof include oxide adducts, perfluoroalkyl betaines, and perfluoroalkylamine oxide compounds.

  In addition to the above, as the fluorosurfactant, those appropriately synthesized may be used, or commercially available products may be used. Examples of commercially available products include S · 144, S · 145 (Asahi Glass Co., Ltd.); FC · 170C, FC · 430, Florard FC4430 (Sumitomo 3M Ltd.); FSO, FSO · 100, FSN, FSN · 100 FS · 300 (manufactured by Dupont); FT · 250, 251 (manufactured by Neos Co., Ltd.) and the like. Among these, FSO, FSO • 100, FSN, FSN • 100, and FS • 300 manufactured by Dupont are preferable. A fluorine-type surfactant may be used individually by 1 type, or may use 2 or more types together.

[1-3. (Drive mechanism)
The drive mechanism of the present embodiment performs a cleaning operation in which at least one of the absorbing member and the recording head is moved relative to the other, and the ink composition attached to the nozzle forming surface is removed by the absorbing member. is there. Those having a pressing member that relatively presses the absorbing member containing the impregnating liquid and the nozzle forming surface at 50 gf or more and 500 gf or less are preferable, and those having a pressing member that presses at 75 gf or more and 300 gf or less are more preferable. When the pressing force is 50 gf or more, the ink wiping property is excellent. Furthermore, even when there is a level difference between the nozzle plate and the nozzle plate cover, it is excellent in preventing or removing ink from adhering and accumulating in the gap. Further, when the pressing force is 500 gf or less, the storage stability of the liquid repellent film is further improved. The drive mechanism is not particularly limited, and for example, the absorbing member and the ink forming surface can be brought into contact with each other by pressing the absorbing member from the side opposite to the side in contact with the nozzle forming surface. Further, the head can be driven to bring the absorbing member into contact with the ink forming surface. The load referred to here is the sum of the loads applied to the nozzle formation surface from the entire drive mechanism.

  Furthermore, it is preferable that the drive mechanism relatively moves the absorbing member and the recording head at a speed of 1 cm / s or more and 10 cm / s or less. By being in the above range, cleaning properties and storage stability of the liquid repellent film are further improved. The speed of the cleaning operation is a slow speed of about 1/5 to 1/20 as compared with the speed at which the normal recording head moves when recording an image, but is limited to this speed relationship. I don't mean.

  Although a press member is not specifically limited, For example, what was coat | covered with the elastic member is preferable. The Shore A hardness of the elastic member is preferably 10 or more and 60 or less, and more preferably 10 or more and 50 or less. Thereby, a press member and an absorption member bend at the time of a press, and an absorption member can be pushed in with respect to the uneven surface which consists of a nozzle formation surface. In particular, when there is a nozzle plate cover, the absorbing member can be pushed into the corner (gap) between the nozzle forming surface and the nozzle plate cover protruding from the nozzle forming surface, and ink accumulation can be suppressed. Therefore, the cleaning property is further improved.

[2. (Operation of the device)
FIG. 1 is a perspective view of the ink jet recording apparatus of the present embodiment. FIG. 2 is a perspective view of the wiper unit. FIG. 3A is a front view of the wiper cassette, and FIG. 3B is a front view of the wiper cassette with the housing omitted. The printer shown in FIGS. 1 to 3 is configured as described above, and the operation of this printer will be described in detail below. As shown in FIG. 1, a head maintenance device 26 for performing maintenance of the recording head 22 is provided at the home position HP provided on the right side of the recording area in which the recording paper P is conveyed in the frame 12. .

  The head maintenance device 26 includes a wiper cassette 31 on which an absorbing member 30 for wiping ink from the nozzle forming surface of the recording head 22 is mounted, a wiper holder 32 to which the wiper cassette 31 is detachably mounted, and the wiper holder 32. A wiper unit 34 including a moving mechanism 33 that moves the recording head 22 in the nozzle row direction (the recording medium conveyance direction in FIG. 1) is provided. In addition to the wiper unit 34, the head maintenance device 26 has a cap (not shown) provided so as to be able to contact the nozzle forming surface of the recording head 22 so as to surround the nozzle, and the recording head 22 via the cap. A suction pump (not shown) that is driven to suck and discharge ink having increased viscosity from the inside as waste ink may be provided. The drive mechanism according to the present embodiment is a mechanism for pressing the absorbing member containing the impregnating liquid and the nozzle forming surface, and includes at least the pressing member 87 and the bar spring 90 in FIG. Can also be included.

  As shown in FIGS. 3 (a) and 3 (b), it extends horizontally in the front-rear direction, which is the short direction of the casing 80, inside the casing 80 that forms a substantially rectangular box that forms the exterior of the wiper cassette 31. A pair of rollers 81 and 82 having an axis are accommodated at a distance in the left-right direction, which is the longitudinal direction of the housing 80. A long absorbent member 30 for wiping ink from the nozzle forming surface of the recording head 22 is hung between the pair of rollers 81 and 82. Of the pair of rollers 81 and 82, the feeding roller 81 as a first roller provided on the left side closer to the recording area where the recording head 22 performs recording on the recording paper P is a winding roller 81, 82. The used unused absorbing member 30 is fed out. On the other hand, of the pair of rollers 81 and 82, the winding roller 82 as the second roller on the right side that is opposite to the recording area where the recording head 22 performs recording on the recording paper P is: The used absorbent member 30 unwound from the feed roller 81 and used for wiping is wound up. The feeding roller 81 and the take-up roller 82 are located at substantially the same height. A feeding gear is provided at one end portion (front end portion) in the axial direction of the feeding roller 81 exposed to the outside of the housing 80 so as to be integrally rotatable with the feeding roller 81. In addition, winding gears 84 and 85 are provided at both ends in the axial direction of the winding roller 82 exposed to the outside of the casing 80 so as to be rotatable together with the winding roller 82.

  In addition, on the inside of the housing 80, a plurality of (four in this embodiment) rollers 86, 88, 89 and a pressing member 87 are provided on the feeding path of the absorbing member 30 from the feeding roller 81 to the take-up roller 82. Is provided. These rollers 86, 88, 89 and the pressing member 87 extend in the front-rear direction in parallel with the feeding roller 81 and the take-up roller 82, and both end portions in the front-rear direction are provided in the side wall portion of the housing 80. Etc., and is supported rotatably.

  Specifically, a portion of the absorbing member 30 that is fed from the feed roller 81 is wound around the pressing member 87 that is provided obliquely above and to the right of the feed roller 81. The shaft portions 87 a at both ends in the axial direction of the pressing member 87 are supported from below by bar springs 90 fixed to the outer surfaces on both front and rear sides of the housing 80. The bar spring 90 supports the shaft portion 87a of the pressing member 87 from below at an intermediate position in the longitudinal direction. Note that the shaft portion 87 a of the pressing member 87 is inserted back and forth with respect to the bearing hole 91 provided in the housing 80, and is a hole on the upper side of the bearing hole 91 according to the upward biasing force acting from the bar spring 90. It is in close contact with the edge. The shaft portion 87a of the pressing member 87 is supported between the bar spring 90 and the hole edge of the bearing hole 91 so as to be rotatable from both upper and lower sides. The uppermost portion of the circumferential surface of the pressing member 87 is located above the upper surface of the housing 80, and the portion of the absorbing member 30 that is wound around the pressing member 87 projects upward from the upper surface of the housing 80. Yes. Further, the uppermost portion of the circumferential surface of the pressing member 87 is located above the nozzle formation surface of the recording head 22.

  The drive mechanism of this embodiment including at least the bar spring 90 and the pressing member 87 presses the absorbing member 30 containing the impregnating liquid against the nozzle forming surface 22 by the upward biasing force of the bar spring 90 and presses the load. Can be added. The pressing load of this embodiment refers to a spring load. As long as the mechanism for applying the pressing load can press the absorbing member against the nozzle forming surface with a certain load, not only a spring but also rubber may be used, The load may be applied by a method such as applying a load by controlling the mechanical member.

  A relay roller 89 is provided below the pressing member 87 so as to wind a portion of the absorbing member 30 that is fed from the pressing member 87. A sandwiching roller 92 that sandwiches the absorbing member 30 with the relay roller 89 is provided at a position opposite to the relay roller 89 with the absorbing member 30 interposed therebetween. A spring member 93 as an urging member is interposed between the inner surface of the bottom wall of the housing 80 and the sandwiching roller 92. The clamping roller 92 is urged in a direction approaching the relay roller 89 by the spring member 93.

  Note that a relay gear 94 is relayed to the end of the shaft portion 89a on one side (rear side in FIGS. 3A and 3B) in the axial direction exposed to the outside from the side wall portion of the casing 80 in the relay roller 89. It is provided so as to be able to rotate integrally with the roller 89. Further, the shaft portions 92 a at both ends in the axial direction of the sandwiching roller 92 are exposed at the outer ends from the notch groove-shaped bearing portions formed when the elastic piece portions are cut out and formed on the side wall portions of the housing 80. Yes.

  Further, on the feeding path of the absorbing member 30 from the feeding roller 81 to the take-up roller 82, the absorbing member 30 is provided between the feeding roller 81 and the pressing member 87 and between the pressing member 87 and the relay roller 89. There are provided tension rollers 86 and 88 for applying tension. It should be noted that end portions of the shaft portions 86 a and 88 a at both ends in the axial direction of the tension rollers 86 and 88 are exposed to the outside from the circular concave bearing portion provided on the side wall portion of the housing 80.

[Ink composition]
The ink jet recording apparatus of the present embodiment is not particularly limited as long as it uses an inorganic pigment-containing ink composition, and may use another ink composition. Hereinafter, it is included in the inorganic pigment-containing ink composition and other ink compositions of the present embodiment (hereinafter, the inorganic pigment-containing ink composition and other ink compositions are simply referred to as “ink composition”). Or the additive (component) which may be contained is demonstrated.

[1. Color material)
The inorganic pigment-containing ink composition of the present embodiment is not particularly limited as long as it contains an inorganic pigment. In addition, the other ink composition may include a color material, and the color material is selected from pigments and dyes other than inorganic pigments.

(1-1. Pigment)
The inorganic pigment is not particularly limited, and examples thereof include carbon black, iron oxide, titanium oxide, and silica oxide.

  The inorganic pigment contained in the inorganic pigment-containing ink composition preferably has an average particle size of 200 nm or more, and more preferably 250 nm or more. Moreover, it is preferable that the upper limit of an average particle diameter is 4 micrometers or less, More preferably, it is 2 micrometers or less. Furthermore, the Mohs hardness of the inorganic pigment is preferably more than 2.0, and more preferably 5 or more. The upper limit of the hardness is preferably 8 or less. The inorganic pigment in the above range is relatively easy to damage the liquid-repellent film, and the liquid-repellent film storage stability is impaired in a normal ink-jet recording apparatus. Even when an inorganic pigment in the range is used, the liquid repellent film storage stability is improved by having the above-described configuration. In addition, the Mohs hardness of the organic pigment is usually 1 or less, and the liquid repellent film storage stability tends to be less than that of the inorganic pigment.

  The inorganic pigment-containing ink composition preferably contains 20% by mass or less of an inorganic pigment. In particular, when the inorganic pigment-containing ink composition is a white ink composition, the inorganic pigment concentration is preferably 5% by mass or more. If it is the said range, the characteristic for which inorganic pigment ink is requested | required will be maintained, and if it is the inkjet recording device of this embodiment, liquid-repellent film preservability is maintained.

  The Mohs hardness is measured by a Mohs hardness meter. The Mohs hardness tester is It was devised by Mohs, and 10 kinds of minerals ranging from soft minerals to harder minerals were put in a box, and the hardness ranking was shown as 1 degree, 2 degrees, ... 10 degrees from the softest one. is there. Standard minerals are as follows (numbers indicate hardness). 1: Kaseki, 2: Gypsum, 3: Boulder stone, 4: Firefly stone, 5: Linkai stone, 6: Seiko stone, 7: Sekiei, 8: Topaz, 9: Corundum, 10: Diamond. When the surface of a mineral sample for which hardness is desired is to be scratched with these minerals, the hardness can be compared by the resistance (whether it is scratched or not). For example, when the calcite is scratched, the hardness of the sample is greater than 3 degrees. If the fluorite is scratched and the fluorite is not scratched, the hardness of the sample is less than 4 degrees. At this time, the hardness of the sample is 3-4 or 3.5. When the scratches are somewhat scratched, the hardness of the sample shows the same level of hardness as the standard mineral used. The hardness of the Mohs hardness tester is just an order, not an absolute value.

  The inorganic pigment satisfying a Mohs hardness exceeding 2.0 is not particularly limited. For example, simple metals such as gold, silver, copper, aluminum, nickel, zinc; cerium oxide, chromium oxide, aluminum oxide, zinc oxide, magnesium oxide , Oxides such as silicon oxide, tin oxide, zirconium oxide, iron oxide and titanium oxide; sulfates such as calcium sulfate, barium sulfate and aluminum sulfate; silicates such as calcium silicate and magnesium silicate; boron nitride, titanium nitride Nitrides such as silicon carbide, titanium carbide, boron carbide, tungsten carbide, zirconium carbide and the like; borides such as zirconium boride and titanium boride and the like. Among these, preferable inorganic pigments include aluminum, aluminum oxide, titanium oxide, zinc oxide, zirconium oxide, silicon oxide and the like. More preferably, titanium oxide, silicon oxide, and aluminum oxide are mentioned. In titanium oxide, the rutile type has a Mohs hardness of about 7 to 7.5, and the anatase type has a range of 6.6 to 6. Rutile titanium oxide is low in production cost, is a preferred crystal system, and can exhibit good whiteness. Therefore, when rutile type titanium dioxide is used, it becomes an ink jet recording apparatus having liquid repellent film storage stability and capable of producing a printed matter with good whiteness at low cost.

  Examples of white inorganic pigments include alkaline earth metal sulfates such as barium sulfate, alkaline earth metal carbonates such as calcium carbonate, silicas such as fine silicate and synthetic silicate, calcium silicate, alumina, and alumina. Examples thereof include metal compounds such as hydrate, titanium oxide, and zinc oxide, and talc and clay. In particular, titanium oxide is known as a white pigment having favorable hiding properties, coloring properties, and dispersed particle sizes.

  Examples of organic pigments include, but are not limited to, quinacridone pigments, quinacridone quinone pigments, dioxazine pigments, phthalocyanine pigments, anthrapyrimidine pigments, ansanthrone pigments, indanthrone pigments, flavanthrone pigments, Examples include perylene pigments, diketopyrrolopyrrole pigments, perinone pigments, quinophthalone pigments, anthraquinone pigments, thioindigo pigments, benzimidazolone pigments, isoindolinone pigments, azomethine pigments, and azo pigments. It is done. Specific examples of the organic pigment include the following.

  Examples of pigments used for cyan ink include C.I. I. Pigment Blue 1, 2, 3, 15, 15: 1, 15: 2, 15: 3, 15: 4, 15: 6, 15:34, 16, 18, 22, 60, 65, 66, C.I. I. Bat Blue 4, 60 and the like. Among them, C.I. I. At least one of Pigment Blue 15: 3 and 15: 4 is preferable.

  Examples of pigments used in magenta ink include C.I. I. Pigment Red 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 14, 15, 16, 17, 18, 19, 21, 22, 23, 30, 31, 32, 37, 38, 40, 41, 42, 48 (Ca), 48 (Mn), 57 (Ca), 57: 1, 88, 112, 114, 122, 123, 144, 146, 149, 150, 166, 168 170, 171, 175, 176, 177, 178, 179, 184, 185, 187, 202, 209, 219, 224, 245, 254, 264, C.I. I. Pigment violet 19, 23, 32, 33, 36, 38, 43, 50 and the like. Among them, C.I. I. Pigment red 122, C.I. I. Pigment red 202, and C.I. I. One or more selected from the group consisting of Pigment Violet 19 is preferred.

  Examples of pigments used in yellow ink include C.I. I. Pigment Yellow 1, 2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 14, 16, 17, 24, 34, 35, 37, 53, 55, 65, 73, 74, 75, 81, 83, 93, 94, 95, 97, 98, 99, 108, 109, 110, 113, 114, 117, 120, 124, 128, 129, 133, 138, 139, 147, 151, 153, 154, 155, 167, 172, 180, 185, 213 and the like. Among them, C.I. I. One or more selected from the group consisting of CI Pigment Yellow 74, 155, and 213 are preferred. In addition, as a pigment used for inks of colors other than the above, such as green ink and orange ink, conventionally known pigments can be used.

  The average particle diameter of the pigments other than the inorganic pigment is preferably 250 nm or less because clogging at the nozzle can be suppressed and ejection stability is further improved. In addition, the average particle diameter in this specification is based on a volume. As a measuring method, for example, it can be measured by a particle size distribution measuring apparatus using a laser diffraction scattering method as a measurement principle. Examples of the particle size distribution measuring apparatus include a particle size distribution meter (for example, Microtrac UPA manufactured by Nikkiso Co., Ltd.) having a dynamic light scattering method as a measurement principle.

(1-2. Dye)
In the present embodiment, a dye can be used as the color material. The dye is not particularly limited, and acid dyes, direct dyes, reactive dyes, and basic dyes can be used.

  The content of the color material is preferably 0.4 to 12% by mass, and more preferably 2 to 5% by mass with respect to the total mass (100% by mass) of the ink composition.

[2. resin〕
The ink that is suitably used in the ink jet recording apparatus of the above-described embodiment and contains an inorganic pigment preferably has the following characteristics (1) or (2) in terms of composition.
(1) The ink composition for ink jet recording contains a first resin having a heat distortion temperature of 10 ° C. or less (hereinafter referred to as “first ink”).
(2) The ink composition for inkjet recording contains the second resin and does not substantially contain glycerin (hereinafter referred to as “second ink”).

  These ink compositions tend to solidify on the nozzle formation surface and the absorbing member and tend to promote damage to the liquid repellent film, but the present invention can satisfactorily prevent this.

  The first ink contains a first resin having a heat distortion temperature of 10 ° C. or lower. Such a resin has a property of firmly adhering to a material having high flexibility and absorbability, such as a fabric. On the other hand, coating and solidification rapidly progress and adhere as a solid matter to the nozzle forming surface, the absorbent material, and the like.

  The second ink substantially does not contain glycerin having a boiling point of 290 ° C. under 1 atm. If the colored ink substantially contains glycerin, the drying property of the ink is greatly reduced. As a result, in various recording media, particularly recording media with non-ink-absorbing properties or low-absorbing properties, not only unevenness of image density but also ink fixing properties cannot be obtained. In addition, since glycerin is not contained, moisture or the like as a main solvent in the ink rapidly volatilizes, and the ratio of the organic solvent in the second ink increases. In this case, the thermal deformation temperature (particularly the film increasing temperature) of the resin is lowered, and solidification by the film is further promoted. Furthermore, it is preferable that substantially no alkyl polyols (excluding the above-mentioned glycerin) having a boiling point of 280 ° C. or higher at 1 atm. In the case of the second ink, in the case of a recording apparatus having a heating mechanism for heating the recording medium conveyed to a position facing the recording head, the ink in the vicinity of the recording head is dried, and the problem becomes more prominent. However, if it is this invention, it can prevent favorably. The heating temperature is preferably 30 ° C. or higher and 80 ° C. or lower from the viewpoints of ink storage stability and recorded image quality. The heating mechanism is not particularly limited, and examples include a heater, a hot air heater, and an infrared heater.

  Here, “substantially free” in the present specification means not to contain more than the amount that fully exhibits the significance of addition. Speaking quantitatively, it is preferable that glycerin does not contain 1.0 mass% or more with respect to the total mass (100 mass%) of the colored ink, and more preferably does not contain 0.5 mass% or more. It is more preferable not to contain 0.1% by mass or more, even more preferable not to contain 0.05% by mass or more, particularly preferable not to contain 0.01% by mass or more, and not to contain 0.001% by mass or more. Most preferred.

  The heat deformation temperature of the first resin is 10 ° C. or less. Furthermore, it is preferably −10 ° C. or lower, and more preferably −15 ° C. or lower. When the glass transition temperature of the fixing resin is within the above range, the fixability of the pigment in the recorded matter is further improved, and as a result, the abrasion resistance is improved. In addition, although it does not specifically limit about the minimum of heat deformation temperature, It is good in it being -50 degreeC or more.

  The thermal deformation temperature of the second resin is less likely to cause clogging of the head and can improve the abrasion resistance of the recorded matter. Therefore, the lower limit is preferably 40 ° C. or higher, and preferably 60 ° C. or higher. It is more preferable. A preferable upper limit is 100 ° C. or lower.

  Here, the “thermal deformation temperature” in the present specification is a temperature value represented by a glass transition temperature (Tg) or a minimum film forming temperature (MFT). That is, “the thermal deformation temperature is 40 ° C. or higher” means that either Tg or MFT may be 40 ° C. or higher. In addition, since MFT can grasp | ascertain the superiority or inferiority of the redispersibility of resin rather than Tg, it is preferable that the said heat deformation temperature is a temperature value represented by MFT. If the ink composition is excellent in resin redispersibility, the ink composition does not adhere and the head is less likely to be clogged.

  Tg in this specification is described as a value measured by a differential scanning calorimetry method. Further, MFT in this specification is described as a value measured by ISO 2115: 1996 (title: plastic-polymer dispersion-measurement of white point temperature and minimum film forming temperature).

  Although it does not specifically limit as resin, For example, poly (meth) acrylic acid ester or its copolymer, polyacrylonitrile or its copolymer, polycyanoacrylate, polyacrylamide, and poly (meth) acrylic acid etc. ) Acrylic polymer; Polyethylene, polypropylene, polybutene, polyisobutylene, and polystyrene, and their copolymers, and polyolefin polymers such as petroleum resin, coumarone-indene resin, and terpene resin; Polymers, vinyl acetate or vinyl alcohol polymers such as polyvinyl alcohol, polyvinyl acetal, and polyvinyl ether; polyvinyl chloride or copolymers thereof, polyvinylidene chloride, fluororesin, and halogen-containing polymers such as fluoro rubber ; Polybi Nitrogen-containing vinyl polymers such as rucarbazole, polyvinyl pyrrolidone or copolymers thereof, polyvinyl pyridine, and polyvinyl imidazole; diene polymers such as polybutadiene or copolymers thereof, polychloroprene, and polyisoprene (butyl rubber); and Other ring-opening polymerization resins, condensation polymerization resins, natural polymer resins, and the like can be given.

  Commercially available resins include, for example, Hitech E-7525P, Hitech E-2213, Hitech E-9460, Hitech E-9015, Hitech E-4A, Hitech E-5403P, Hitech E-8237 (all trade names, Toho Chemical Co., Ltd.) (TOHO Chemical Industry Co., Ltd.), AQUACER 507, AQUACER 515, AQUACER 840 (all trade names, manufactured by BYK Japan KK), JONCRYL 67, 611, 678 690 (all are trade names, manufactured by BASF) and the like.

  The resin may be anionic, nonionic, or cationic. Among these, nonionicity or anionicity is preferable from the viewpoint of a material suitable for the head. Resin may be used individually by 1 type and may be used in combination of 2 or more type.

  The content of the resin is preferably 1 to 30% by mass, and more preferably 1 to 5% by mass with respect to the total mass (100% by mass) of the ink composition. When content is in the said range, the glossiness and abrasion resistance of the top coat image formed can be made further excellent.

  Examples of the resin that may be contained in the ink composition include a resin dispersant, a resin emulsion, and a wax. Among these, emulsions are preferred because they have good adhesion and abrasion resistance.

(2-1. Resin dispersant)
When the above-described pigment is contained in the ink composition of the present embodiment, the ink composition may include a resin dispersant so that the pigment can be stably dispersed and held in water. When the ink composition contains a pigment dispersed using a resin dispersant such as a water-soluble resin or a water-dispersible resin (hereinafter referred to as “resin-dispersed pigment”), the ink composition adheres to the recording medium. In this case, at least one of the adhesion between the recording medium and the ink composition and the solidified material in the ink composition can be improved. Among the resin dispersants, a water-soluble resin is preferable because of excellent dispersion stability.

(2-2. Resin emulsion)
The ink composition of this embodiment preferably contains a resin emulsion. By forming a resin film, the resin emulsion exhibits an effect of sufficiently fixing the ink composition on the recording medium and improving the abrasion resistance of the image. The recorded matter recorded by using the ink composition containing the resin emulsion due to the above effects is excellent in adhesion and abrasion resistance particularly on a fabric, a non-ink-absorbing or low-absorbing recording medium. Become. On the other hand, solidification of the inorganic pigment tends to be promoted, but the present invention can satisfactorily prevent problems caused by solidification.

  The resin emulsion functioning as a binder is preferably contained in the ink composition in an emulsion state. By including a resin functioning as a binder in the ink composition in an emulsion state, it is easy to adjust the viscosity of the ink composition to an appropriate range in the ink jet recording system, and the storage stability and ejection stability of the ink composition. It will be excellent.

  The resin emulsion is not particularly limited. For example, (meth) acrylic acid, (meth) acrylic ester, acrylonitrile, cyanoacrylate, acrylamide, olefin, styrene, vinyl acetate, vinyl chloride, vinyl alcohol, vinyl ether, vinyl pyrrolidone, Examples thereof include homopolymers or copolymers of vinyl pyridine, vinyl carbazole, vinyl imidazole, and vinylidene chloride, fluororesins, and natural resins. Among them, at least one of (meth) acrylic resin and styrene- (meth) acrylic acid copolymer resin is preferable, and at least one of acrylic resin and styrene-acrylic acid copolymer resin is more preferable, styrene. -Acrylic acid copolymer resin is more preferable. In addition, said copolymer may be any form among a random copolymer, a block copolymer, an alternating copolymer, and a graft copolymer.

  The resin emulsion may be a commercially available product or may be prepared using an emulsion polymerization method or the like as follows. As a method for obtaining the resin in the ink composition in an emulsion state, the above-mentioned water-soluble resin monomer is emulsion-polymerized in water containing a polymerization catalyst and an emulsifier. The polymerization initiator, the emulsifier, and the molecular weight modifier used in the emulsion polymerization can be used according to a conventionally known method.

  The average particle size of the resin emulsion is preferably in the range of 5 nm to 400 nm, more preferably in the range of 20 nm to 300 nm, in order to further improve the storage stability and ejection stability of the ink.

  A resin emulsion may be used individually by 1 type, and may be used in combination of 2 or more type. Among the resins, the content of the resin emulsion is preferably in the range of 0.5 to 15% by mass with respect to the total mass (100% by mass) of the ink composition. When the content is within the above range, the solid content concentration can be lowered, so that the discharge stability can be further improved.

(2-3. Wax)
The ink composition of the present embodiment may contain a wax. By including the wax in the ink composition, the ink composition is more excellent in fixability on a non-ink-absorbing and low-absorbing recording medium. Among the waxes, an emulsion or suspension type is more preferable. Examples of the wax include, but are not limited to, polyethylene wax, paraffin wax, and polypropylene wax. Among them, polyethylene wax described later is preferable.

  When the ink composition contains polyethylene wax, the ink can have excellent abrasion resistance.

  The average particle diameter of the polyethylene wax is preferably in the range of 5 nm to 400 nm, and more preferably in the range of 50 nm to 200 nm, in order to further improve the storage stability and ejection stability of the ink.

  The polyethylene wax content (in terms of solid content) is preferably in the range of 0.1 to 3% by mass and more preferably in the range of 0.3 to 3% by mass with respect to the total mass (100% by mass) of the ink composition. The range of 0.3 to 1.5% by mass is more preferable. When the content is within the above range, the ink composition can be well solidified and fixed on the recording medium, and the storage stability and ejection stability of the ink are further improved.

[3. Antifoam agent
The ink composition of this embodiment may contain an antifoaming agent. More specifically, it is preferable that at least one of the ink composition and the impregnating liquid of the present embodiment includes an antifoaming agent. When the ink composition contains an antifoaming agent, it is possible to prevent foaming, and as a result, it is possible to prevent a problem that bubbles enter the nozzle.

  Examples of the antifoaming agent include, but are not limited to, a silicon-based antifoaming agent, a polyether-based antifoaming agent, a fatty acid ester-based antifoaming agent, and an acetylene glycol-based antifoaming agent. Among these, a silicon-based antifoaming agent and an acetylene glycol-based antifoaming agent are preferable because they are excellent in ability to appropriately maintain surface tension and interfacial tension and hardly generate bubbles. Moreover, as for the HLB value based on the Griffin method of an antifoamer, 5 or less is more preferable.

[4. Surfactant]
The ink composition of the present embodiment may contain a surfactant (excluding those listed as the antifoaming agent described above. That is, the ink composition is limited to those having an HLB value of more than 5 by the Griffin method). Examples of the surfactant include, but are not limited to, nonionic surfactants. The nonionic surfactant has an action of spreading the ink uniformly on the recording medium. Therefore, when ink jet recording is performed using an ink containing a nonionic surfactant, a high-definition image with almost no bleeding can be obtained. Examples of such nonionic surfactants include, but are not limited to, silicon-based, polyoxyethylene alkyl ether-based, polyoxypropylene alkyl ether-based, polycyclic phenyl ether-based, sorbitan derivatives, and fluorine-based interfaces. Examples of the surfactant include silicon surfactants.

  Silicon-based surfactants are superior to other nonionic surfactants in their ability to uniformly spread ink so as not to cause bleeding on the recording medium.

  Although it does not specifically limit as a silicon-type surfactant, A polysiloxane type compound is mentioned preferably. Although it does not specifically limit as the said polysiloxane type compound, For example, polyether modified organosiloxane is mentioned. Although it does not specifically limit as a commercial item of the said polyether modified organosiloxane, For example, BYK-306, BYK-307, BYK-333, BYK-341, BYK-345, BYK-346, BYK-348, BYK-349 (Product name, manufactured by BYK), KF-351A, KF-352A, KF-353, KF-354L, KF-355A, KF-615A, KF-945, KF-640, KF-642, KF-643, KF-6020, X-22-4515, KF-6011, KF-6012, KF-6015, KF-6017 (all trade names, manufactured by Shin-Etsu Chemical Co., Ltd.), etc. It is done.

  Surfactant may be used individually by 1 type, and 2 or more types may be mixed and used for it. The surfactant content is further improved in the storage stability and ejection stability of the ink. Therefore, the content of the surfactant is from 0.1% by mass to 3% by mass with respect to the total mass (100% by mass) of the ink. A range is preferable.

[5. water〕
The ink composition of this embodiment may contain water. In particular, when the ink is a water-based ink, water is a main medium of the ink, and becomes a component that evaporates and scatters when the recording medium is heated in ink jet recording.

  Examples of water include water from which ionic impurities have been removed as much as possible, such as pure water such as ion exchange water, ultrafiltration water, reverse osmosis water, and distilled water, and ultrapure water. Further, when water sterilized by ultraviolet irradiation or addition of hydrogen peroxide is used, generation of mold and bacteria can be prevented when the pigment dispersion and ink using the same are stored for a long period of time.

  The water content is not particularly limited, and may be appropriately determined as necessary.

[6. Organic solvent〕
The ink composition of this embodiment may contain a volatile water-soluble organic solvent. Although it does not specifically limit as an organic solvent, For example, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, 1,3-propanediol, 1,2-butanediol, 1,2-pentanediol, 1 , 2-hexanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 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-n-butyl ether, triethylene glycol mono-n-butyl ether Diethylene glycol mono-t-butyl ether, 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, propylene glycol mono-n- Butyl ether, dipropylene glycol mono-n-butyl ether, dipropylene glycol mono-n-propyl ether, dipropylene glycol mono-iso-propyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, diethylene glycol ethyl methyl ether, diethylene glycol butyl methyl Ete , Triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, dipropylene glycol dimethyl ether, dipropylene glycol diethyl ether, tripropylene glycol dimethyl ether, methanol, ethanol, n-propyl alcohol, iso-propyl alcohol, n-butanol, 2-butanol, tert Alcohols or glycols such as butanol, iso-butanol, n-pentanol, 2-pentanol, 3-pentanol, and tert-pentanol, N, N-dimethylformamide, N, N-dimethylacetamide, 2 -Pyrrolidone, N-methyl-2-pyrrolidone, 2-oxazolidone, 1,3-dimethyl-2-imidazolidinone, dimethyl sulfoxide, sulfo Orchid and 1,1,3,3-tetramethylurea.

  An organic solvent may be used individually by 1 type, and may be used in combination of 2 or more type. The content of the organic solvent is not particularly limited and may be appropriately determined as necessary.

[7. pH adjuster]
The ink composition of this embodiment may contain a pH adjuster. Examples of the pH adjuster include inorganic alkalis such as sodium hydroxide and potassium hydroxide, ammonia, diethanolamine, triethanolamine, triisopropanolamine, morpholine, potassium dihydrogen phosphate, and disodium hydrogen phosphate.

  A pH adjuster may be used individually by 1 type, and may be used in combination of 2 or more type. The content of the pH adjuster is not particularly limited, and may be appropriately determined as necessary.

[8. Other ingredients
In addition to the above components, the ink composition of the present embodiment may further contain an antiseptic / fungicide, a rust inhibitor, a chelating agent, and the like.

[9. Method for producing ink composition]
The ink composition of the present embodiment can be obtained by mixing the above-described components (materials) in an arbitrary order, performing filtration or the like as necessary, and removing impurities. Here, it is preferable to prepare the pigment in a state of being uniformly dispersed in a solvent before mixing, because the handling becomes simple.

  As a method for mixing each material, a method in which materials are sequentially added to a container equipped with a stirring device such as a mechanical stirrer or a magnetic stirrer and stirred and mixed is preferably used. As a filtration method, for example, centrifugal filtration or filter filtration can be performed as necessary.

[10. Surface tension of ink composition]
The surface tension of the ink composition is not particularly limited, but is preferably 15 to 35 mN / m. As a result, it is possible to ensure the permeability of the ink composition to the absorbing member and the ability to prevent bleeding when recording, and the ink wiping property during the cleaning operation is improved. As described above, a method of measuring the surface tension of the ink composition using a generally used surface tension meter (for example, a surface tension meter CBVP-Z manufactured by Kyowa Interface Science Co., Ltd.) can be exemplified. Further, the difference between the surface tension of the ink composition and the surface tension of the impregnating liquid preferably has a relationship of 10 mN / m or less. This can prevent the surface tension of the ink composition from being extremely lowered when both are mixed in the vicinity of the nozzle.

  Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples. The present invention is not limited in any way by the following examples.

[1. Ink composition material]
The main materials for the ink compositions used in the following examples and comparative examples are as follows.
[Color material]
・ C. I. Pigment Black 7 (carbon black, average particle size 100 nm, Mohs hardness 1-2)
〔Organic solvent〕
・ 1,2-hexanediol ・ 2-pyrrolidone ・ propylene glycol (resin emulsion)
-Styrene-acrylic acid copolymer resin emulsion (Tg 85 ° C, average particle size 140 nm)
[Polyethylene wax]
・ AQUACER 515 (trade name, manufactured by BYK)
[Silicon surfactant]
・ BYK348 (Brand name, manufactured by BYK)
[Acetylene glycol antifoaming agent]
・ Surfinol DF110D (trade name, HLB value = 3, manufactured by Nissin Chemical Industry Co., Ltd.)
[PH adjuster]
・ Triethanolamine (Measuring method of average particle size)
The average particle diameter was measured in accordance with the trade name “Microtrac UPA” of Nikkiso Co., Ltd.
[Measurement method of Tg]
The Tg was measured using a product name “DSC-6200R” manufactured by SII Nano Technologies, Inc. using a dried emulsion as a sample.

[2. Preparation of pigment dispersion for ink composition]
Water-soluble resin (methacrylic acid / butyl acrylate / styrene / hydroxyethyl acrylate copolymerized at a mass ratio of 25/50/15/10, weight average molecular weight 12,000) 40 parts by mass, potassium hydroxide 7 parts by mass , 23 parts by mass of water and 30 parts by mass of triethylene glycol mono-n-butyl ether were added and heated at 80 ° C. with stirring to prepare an aqueous resin solution.

  To 1.75 kg of the above-mentioned aqueous resin solution (solid content: 43%), 3.0 kg of a coloring material and 10.25 kg of water were blended, and the mixture was stirred with a mixing stirrer and premixed to obtain a mixed solution. The above mixed solution was dispersed by a multi-pass method using a horizontal type bead mill equipped with a multi-disc type impeller having an effective volume of 1.5 liters filled with 85% of 0.5 mm zirconia beads. Specifically, two passes were performed at a bead peripheral speed of 8 m / sec and a discharge amount of 30 liters per hour, to obtain a pigment dispersion mixed liquid having an average particle diameter of 325 nm. Next, the pigment dispersion mixture was circulated and dispersed using a horizontal annular bead mill having an effective volume of 1.5 liters filled with 95% of 0.05 mm zirconia beads. A screen of 0.015 mm is used, a dispersion of 10 kg of pigment dispersion is performed for 4 hours at a circulation rate of 300 liters / hour at a peripheral speed of beads of 10 m / second, a solid content of 20%, and a water-soluble resin. A 5% aqueous pigment dispersion was obtained.

[3. Preparation of ink composition]
The pigment dispersion prepared above was prepared in such an amount that the colorant would be 2.5% by mass. To this pigment dispersion, each component other than the coloring material shown in the following Table 1 was added so as to have the content (unit: mass%) shown in the following Table 1 to prepare an ink composition (total 100.0). mass%). The ink composition was prepared by putting each component in a container, stirring and mixing with a magnetic stirrer for 2 hours, and filtering through a membrane filter having a pore size of 5 μm to remove foreign matters (impurities) such as dust and coarse particles. For the water-soluble resin, an amount corresponding to one-fourth of the content of each colorant is added to the ink. Further, the surface tension of the ink composition was measured at a liquid temperature of 25 ° C. by the Wilhelmy method using a surface tension meter (manufactured by Kyowa Interface Science Co., Ltd., surface tension meter CBVP-Z, etc.).

[4. Material for impregnating solution]
The main materials for the impregnating liquid used in the following examples and comparative examples are as follows.
(Penetration agent)
Acetylene glycol surfactant (trade name Olfin E1010, manufactured by Nissin Chemical Industry Co., Ltd.)
・ Triethylene glycol monobutyl ether ・ 1,2-hexanediol (humectant)
・ Polyethylene glycol (weight average molecular weight 200)

[5. Preparation of impregnating solution]
Each component shown in the following Table 2 was added so that it might become content (unit: mass%) of the following Table 2, and the impregnation liquid was prepared (total 100.0 mass%). The impregnating solution was prepared by putting each component in a container, stirring and mixing with a magnetic stirrer for 2 hours, and filtering through a membrane filter having a pore size of 5 μm to remove impurities such as dust and coarse particles. The surface tension of the impregnating liquid was measured at a liquid temperature of 25 ° C. by the Wilhelmy method using a surface tension meter (manufactured by Kyowa Interface Science Co., Ltd., surface tension meter CBVP-Z, etc.). The “degree of decrease in surface tension” refers to the surface tension measured by a similar method after preparing a 10% by mass aqueous solution of each material (water content is 90% by mass). In addition, the surface power of water is about 72 mN / m.

[6. Inkjet recording]
A printer PX-H10000 (manufactured by Seiko Epson Corporation) was used (hereinafter referred to as “PX-H10000 modified machine”). The modified part is that a print head provided with a silicon nozzle plate with a water-repellent film and a nozzle plate cover as shown in FIG. 5A, an absorbing member, an elastic member, and a drive mechanism are provided.

A silicon nozzle plate made of single crystal silicon was used. On the nozzle formation surface, a silicon oxide film (SiO ₂ film) formed by a CVD method was formed by introducing SiCl ₄ and water vapor into a chemical vapor deposition (CVD) reactor. The thickness of the SiO ₂ film was 50 nm. Further, an oxygen plasma treatment is performed, and then a water repellent film (thickness 10 nm) is formed on the SiO ₂ film by performing chemical vapor deposition (CVD) using C ₈ F ₁₇ C ₂ H ₄ SiCl ₃ . A silicon nozzle plate with a water repellent film was produced.

A non-woven cupra [density 0.01 (g / cm ² ), cloth thickness 0.4 mm] was used as the absorbent member. A roller having a Shore A hardness of 30 was used as the elastic member. The Shore A hardness is measured by preparing a sheet-like sample by press-molding the outer layer of a foam-molded roller or a thermoplastic elastomer before foam-molding at a temperature of 200 ° C., and the sheet-like sample is subjected to ATSM D-2240. The measurement was performed in accordance with the measurement method specified in 1. In Comparative Example 2, a rubber blade was used instead of the absorbing member and the elastic member.

  The drive mechanism presses the absorbing member with a predetermined load from the side opposite to the side that contacts the nozzle forming surface of the recording head with a predetermined load to bring the absorbing member and the recording head into contact with each other. Thus, the mechanism is configured to perform a cleaning operation for removing the ink composition attached to the nozzle forming surface by the absorbing member.

[7. Examples 1 to 3, 5, 6, Reference Example 4, Comparative Examples 1 to 2]
[7-1. (Cleanability test)
Using a PX-H10000 remodeling machine, printing was performed for 20 minutes using the ink composition shown in Table 1, and then a cleaning operation was performed as shown in Table 3. The cycle was repeated 50 times as one cycle. Thereafter, the degree of ink adhesion growth on the nozzle forming surface was visually observed. A reference diagram showing the degree of ink adhesion growth is shown in FIG.
A: Ink attachment amount is 0.1 mm or less B: Ink attachment amount is more than 0.1 mm and 0.3 mm or less C: Ink attachment amount is more than 0.3 mm and 0.6 mm or less D: Ink attachment amount is more than 0.6 mm Many

[7-2. (Liquid repellent film storage stability test)
Using a PX-H10000 remodeling machine, a suction operation for sucking ink in the head using a suction pump was performed, and then a cleaning operation was performed as shown in Table 3. This cycle was repeated once and repeated 12,000 times. Then, the state of the liquid-repellent film near the nozzle was evaluated with an optical microscope (Union Optical Co., Ltd., high-precision non-contact level difference measuring instrument “Hismet II” DH2). The cleaning operation was performed along the nozzle arrangement direction in each nozzle row, and (Bk, W) corresponding to the first nozzle row and (C, M, Y) corresponding to the second nozzle row were simultaneously cleaned.
A: Level at which liquid-repellent film peeling cannot be observed substantially B: Level at which liquid-repellent film is slightly peeled and discolored, but does not affect ejection C: Liquid-repellent film on the nozzle edge is peeled off, affecting ejection Level D: Level at which the liquid repellent film on the entire surface of the nozzle peels off and the discharge is greatly affected

  From the above results, it was found that when the surface tension of the impregnating liquid is too high, both the cleaning property and the liquid repellent film storage property are inferior (Comparative Example 1). It was also found that the rubber blade was extremely inferior in cleaning properties (Comparative Example 2). In comparison with this, it has been clarified that the ink jet recording apparatus (each example) having the configuration of the present invention is excellent in both of the liquid repellent film storage property and the cleaning property.

  P ... recording paper, HP ... home position, 12 ... frame, 22 ... recording head, 26 ... head maintenance device, 30 ... absorbing member, 31 ... wiper cassette, 32 ... wiper holder, 33 ... moving mechanism, 34 ... wiper unit, 35 ... Nozzle plate cover, 36 ... Nozzle row, 37 ... Nozzle forming surface, 80 ... Housing, 81 ... Feeding roller as first roller, 82 ... Winding roller as second roller, 84 ... Power transmission gear Winding gear as 85, winding gear as power transmission gear, 86 ... tension roller, 86a ... shaft, 87 ... pressing member, 87a ... shaft, 88 ... tension roller, 88a ... shaft, 89 ... winding Relay roller as a hanging roller, 89a ... shaft, 90 ... bar spring, 91 ... bearing hole, 92 ... clamping low Chromatography, 92a ... shaft portion, the spring member as 93 ... urging member, 94 ... intermediate gear.

Claims (9)

A recording head having a plurality of nozzles for discharging an ink composition containing an inorganic pigment, a nozzle forming surface having discharge ports of the plurality of nozzles, and a liquid repellent film provided on the nozzle forming surface;
An absorbing member that absorbs the ink composition containing the inorganic pigment attached to the nozzle outlet and the nozzle forming surface;
A drive mechanism having a pressing member for relatively pressing the absorbing member containing an impregnating liquid and the nozzle forming surface;
The drive mechanism moves at least one of the absorbing member and the recording head relative to the other, and performs a cleaning operation for removing the ink composition adhering to the nozzle formation surface by the absorbing member. And
The surface tension of the impregnation solution Ri Der below 45 mN / m,
The content of the impregnating liquid is 30% by mass or more and 200% by mass or less with respect to 100% by mass of the absorbing member .
Inkjet recording device.   The inkjet recording apparatus according to claim 1, wherein the impregnating liquid contains a penetrant.   The penetrant includes at least one selected from the group consisting of alkanediols having 5 to 8 carbon atoms, glycol ethers, acetylene glycol surfactants, siloxane surfactants, and fluorine surfactants, The ink jet recording apparatus according to claim 2.   4. The inkjet recording apparatus according to claim 2, wherein the content of the penetrant in the impregnating liquid is 1.0% by mass or more and 40% by mass or less. The inkjet recording apparatus according to any one of claims 1 to 4, wherein a content of the impregnating liquid is 30% by mass or more and 100% by mass or less with respect to 100% by mass of the absorbing member. A nozzle plate cover that covers at least a part of the nozzle forming surface is provided on the nozzle forming surface,
The absorbent member is a fabric;
The ink jet recording apparatus according to claim 1.   The ink jet recording apparatus according to claim 1, wherein the absorbing member has a thickness of 0.1 mm or more and 3 mm or less. The pressing member is covered with an elastic member,
The inkjet recording apparatus according to claim 1, wherein the elastic member has a Shore A hardness of 10 or more and 60 or less.   The ink jet recording apparatus according to claim 1, wherein the ink composition further includes a resin emulsion.