JP4581448B2 - Inkjet recording device - Google Patents

Description

The present invention relates to an ink jet recording equipment, more particularly, without shortening the life of the recording head, excellent stability ejection of the ink, and relates to an ink jet recording equipment capable of high-speed printing.

  In recent years, with the rapid development of the information industry, various information processing systems have been developed, and recording methods and apparatuses suitable for the information systems have been developed and put into practical use. Among the above recording methods, the inkjet recording method is capable of recording on various recording media, the hardware (device) is relatively inexpensive, is compact, has excellent quietness, and the like. Of course, it has been widely used in so-called home use.

For the recording head constituting the ink jet recording apparatus, metals such as stainless steel, nickel / cobalt alloy, silicon, polysulfone, polyimide, epoxy resin, etc. are used, but the members constituting such a recording head are: Due to contact with ink, the ink deteriorates due to the solvent component in the ink, shortening the life of the recording head, resulting in a problem that ink droplet ejection performance deteriorates.
On the other hand, speeding up of ink jet recording has been demanded, and the ink itself has been demanded to have high-speed drying (high permeability).

On the other hand, a method for preventing the deterioration of the plastic material by defining the free ammonia concentration in the ink composition is disclosed (for example, see Patent Document 1). There is also a method for preventing deterioration of the resin by using an epoxy-based adhesive and containing a desired amount of a water-soluble solvent with a specified inorganic / organic ratio (I / O ratio) in the ink. It is disclosed (for example, see Patent Document 2).
However, although there is a certain effect in either method, there is still room for improvement.
Japanese Patent Laid-Open No. 11-10851 JP 2002-355958 A

Accordingly, an object of the present invention is to shorten the life of the recording head, excellent stability ejection of the ink, and to provide an ink jet recording equipment capable of high-speed printing.

It is desirable to use an organic solvent having a low solubility parameter (SP value) for ink having high-speed drying properties (high permeability) that enables high-speed printing. The SP value is a value representing the magnitude of the polarity per unit volume of one molecule, but it has been found that the tendency to deteriorate the recording head member becomes strong when the SP value is small. In particular, a resin used as an adhesive has a high risk of deterioration due to its low glass transition point.
The present inventors do not deteriorate the resin (adhesive) even when using ink having high-speed drying (high permeability) that enables high-speed printing, that is, an adhesive having excellent liquid contact properties. The inventors have found the relationship between ink and ink and have arrived at the present invention.

That is, the present invention
<1> consists of a plurality of members made of metal and / or resin, and has at least one recording head using a polyimide-based adhesive in the adhesive portion between the members, further, at least, a coloring agent, the following and one water-soluble organic solvent of the group shown in the water, only contains, and the an ink jet recording apparatus using one kind of ink that does not contain a water-soluble organic solvent other than the water-soluble organic solvent the glass transition temperature of the adhesive is 100 to 190 ° C., and the value of the dispersion force term of the one water-soluble organic solvent soluble Kaido parameter (SP value) of 15.8 to 17.1 met Te is an inkjet recording apparatus, wherein the content of water-soluble organic ink of solvents of that is 2 to 10 mass%.
Group: Ethylene glycol monomethyl ether
Ethylene glycol monoethyl ether
Ethylene glycol monobutyl ether
Diethylene glycol monomethyl ether
Diethylene glycol monoethyl ether
Diethylene glycol monobutyl ether
Propylene glycol monobutyl ether
Triethylene glycol monobutyl ether
1,2-hexanediol
Diethylene glycol isobutyl ether
Propylene glycol monoethyl ether <2> The ink jet recording apparatus according to <1>, wherein at least one ink in which the colorant is a pigment is used.
<3> The inkjet recording apparatus according to <2>, wherein the pigment is a self-dispersible pigment.
<4> The inkjet recording apparatus according to <2>, wherein the pigment is dispersed with a resin.
<5> Any one of the above <2> to <4>, wherein a black ink containing a pigment having self-dispersibility and a color ink containing a pigment dispersed by a resin are used. It is an inkjet recording device of description.
<6> The <1>, wherein the metal is at least one selected from stainless steel, a nickel / cobalt alloy, and silicon, and the resin is at least one selected from polyimide, epoxy, and polyurethane. > Is an ink jet recording apparatus .

According to the present invention, since the ink having high-speed drying (high permeability) is used, high-speed printing is possible, and at the same time, the adhesive that is a constituent of the recording head is not deteriorated. head long life, it is possible to provide superior ink jet recording equipment to ejection stability of the ink.

Hereinafter, the present invention will be described in detail.
<Inkjet recording apparatus>
The ink jet recording apparatus of the present invention is characterized in that a specific adhesive is used for the recording head and a desired amount of a specific water-soluble organic solvent is contained in the ink, and the ink does not shorten the life of the recording head. It is a recording apparatus that is excellent in stable discharge performance and capable of high-speed printing. In this section, the details of the ink and recording head characteristic of the present invention will be described first, and then the inkjet recording apparatus will be described.

(Inkjet recording ink)
The ink in the present invention contains at least a colorant, one type of water-soluble organic solvent in the group shown below , and water , and does not contain a water-soluble organic solvent other than the one type of water-soluble organic solvent. .
Group: Ethylene glycol monomethyl ether
Ethylene glycol monoethyl ether
Ethylene glycol monobutyl ether
Diethylene glycol monomethyl ether
Diethylene glycol monoethyl ether
Diethylene glycol monobutyl ether
Propylene glycol monobutyl ether
Triethylene glycol monobutyl ether
1,2-hexanediol
Diethylene glycol isobutyl ether
Propylene glycol monoethyl ether -water -soluble organic solvent-
In the present invention, it is essential that the value of the dispersion force term of the one water-soluble organic solvent soluble Kaido parameters contained in the ink (SP value) is 15.8 to 17.1. When the value of the dispersion force term is less than 15.8, as will be described later, when the adhesive (resin) according to the present invention having a desired glass transition point is used, the resin melts and the recording head deteriorates. Invite. On the other hand, when the value of the dispersion force term exceeds 17.1, the permeability of the ink into the recording medium becomes low, so that high-speed drying cannot be obtained and high-speed printing cannot be realized. The value of the dispersion force term is more preferably 16.0 to 17.0, and particularly preferably 16.5 to 16.8.

Here, the equation of the solubility parameter (SP value) (Krevelen) used in the present invention is δ = (δd2 + δp2 + δh2) 1/2.
Δd is a dispersion force term, δp is a polar force term, and δh is a hydrogen bond force term. here,
δd = ΣFdi / V
δp = (ΣF2pi) 1/2 / V
δh = (ΣEhi / V) 1/2
Where Fdi is the molar dispersion force contribution term, Fpi is the molar polarity force contribution term, Ehi is the molar hydrogen bond contribution term, and V is the sum of the molar volumes of each atomic group in the compound.
Although the detailed mechanism between the water-soluble organic solvent and the resin deterioration is unknown, it has become clear that the dispersion force term of the SP value correlates with a phenomenon of deteriorating the soft structural portion in the resin.

The water-soluble organic solvent in the present invention, Ru is used include the following. The numerical value in parentheses represents the value of the dispersion force term of the SP value.
Is a water-soluble organic solvent medium, ethylene glycol monomethyl ether (16.0), ethylene glycol monoethyl ether (16.1), ethylene glycol monobutyl ether (16.3), diethylene glycol monomethyl ether (16.5), Diethylene glycol monoethyl ether (16.6), diethylene glycol monobutyl ether (16.6), propylene glycol monobutyl ether (16.0), triethylene glycol monobutyl ether (16.8), 1,2-hexanediol (17.1) ), diethylene glycol isobutyl ether (16.4), with propylene glycol monoethyl ether (15.8), among these, diethylene glycol monomethyl ether (16.5), diethylene glycidyl More preferred are coal monoethyl ether (16.6) and diethylene glycol monobutyl ether (16.6).

In the present invention, used alone the water-soluble organic solvent.

The content of the above Kisui soluble organic solvent, it is essential to 2-10 mass% in the total mass of the ink, more preferably to 4-8% by weight, be 4-6 wt% Particularly preferred. If it is less than 2% by mass, the high-speed drying property may be impaired, and if it exceeds 10% by mass, the viscosity of the ink may increase and ejection stability may be impaired.

-Colorant-
The colorant used in the ink of the present invention may be either a pigment or a dye, but is preferably a pigment. The pigment is more preferably a self-dispersible pigment or a pigment dispersed with a resin.

Self-dispersible pigment A self-dispersible pigment is a pigment that has a hydrophilic functional group on its surface, does not contain a so-called polymer dispersant, and can be dispersed in a solvent itself.
In the present invention, whether or not a pigment is “self-dispersible” is confirmed by the following test.

  First, add the pigment to be measured in water, disperse it without a dispersant using an ultrasonic homogenizer, nanomizer, microfluidizer, ball mill, etc., and dilute with water so that the initial pigment concentration is about 5%. To prepare a dispersion. The initial pigment concentration and 100 g of the dispersion are put into a glass bottle having a diameter of 40 mm and allowed to stand for one day, and then the pigment concentration of the upper layer portion (10% dispersion from the liquid surface in the liquid depth direction) is measured. . When the ratio of the pigment concentration after standing for 1 day to the initial pigment concentration (hereinafter referred to as “self-dispersibility index”) is 98% or more, it was evaluated as “self-dispersibility”.

  At this time, the method for measuring the pigment concentration is not particularly limited, and any method such as a method of measuring the solid content by drying a sample or a method of obtaining the transmittance by diluting to an appropriate concentration may be used. If there is a method of obtaining accurately, it is of course possible to use that method.

  The hydrophilic functional group possessed by the pigment may be any nonionic, anionic or cationic hydrophilic functional group, and in particular, a carboxyl group, a hydroxyl group, a sulfonic acid group, a phosphoric acid group alone or 2 A combination of two or more species is preferable, and among them, a single carboxyl group or a combination of two or more types including a carboxyl group is more preferable.

  When it has a carboxyl group, a sulfonic acid group, or a phosphoric acid group, it can be used as it is in the free acid state, but a case where a part or all of them form a salt is advantageous and preferable in terms of dispersibility. At this time, examples of the substance that forms a salt include various basic substances, and alkali metals, ammonia, or organic onium compounds are preferably used alone or in combination of two or more. The number of hydrophilic functional groups on the pigment surface differs depending on the type of hydrophilic functional group and the type of substance that forms the salt when a salt is formed. 0.8-4 mmol / g is preferable.

  As a pigment into which a hydrophilic functional group is introduced, both inorganic and organic pigments can be used. As the black pigment, carbon black pigments such as furnace black, lamp black, acetylene black, channel black and the like are preferable. , Raven 1080ULTRA, Raven 1060 ULTRA, Raven 790 ULTRA, Raven 780 ULTRA, Raven 760 ULTRA (manufactured by Columbia), Regal 400R, Regal 330R, Regal 660R, Mogu L Black Pearls L, Black Pearls 1300, Monarch 700, Monarch 800, Monarch 880, Monarch 900, Monarch 1000, Monarch 1100, Monarch 1300, Monarch 1400 (manufactured by Cabot Corp.), Color B1, Color Black 18, Color Black FW200, Color Black S150, Color Black S160, Color Black S170, Printex35, PrintexU, PrintexV, Printex140U, Printex140V, Special No. 6, Special Black 5, Special Black 4A, Special Black 4 (manufactured by Degussa), No. 6 25, no. 33, no. 40, no. 47, no. 52, no. 900, no. 2300, MCF-88, MA600, MA7, MA8, MA100 (manufactured by Mitsubishi Chemical Corporation) and the like can be used, but are not limited thereto. Further, magnetic fine particles such as magnetite and ferrite, titanium black and the like may be used as the black pigment.

  Examples of cyan pigments include C.I. I. Pigment Blue-1, C.I. I. Pigment Blue-2, C.I. I. Pigmet Blue-3, C.I. I. Pigmet Blue-15, C.I. I. Pigment Blue-15: 1, C.I. I. Pigment Blue-15: 3, C.I. I. Pigment Blue-15: 34, C.I. I. Pigment Blue-16, C.I. I. Pigment Blue-22, C.I. I. Pigment Blue-60 and the like, but are not limited thereto.

  Examples of magenta pigments include C.I. I. Pigment Red 5, C.I. I. Pigment Red 7, C.I. I. Pigment Red 12, C.I. I. Pigment Red 48, C.I. I. Pigment Red 48: 1, C.I. I. Pigment Red 57, C.I. I. Pigment Red 112, C.I. I. Pigment Red 122, C.I. I. Pigment Red 123, C.I. I. Pigment Red 146, C.I. I. Pigment Red 168, C.I. I. Pigment Red 184, C.I. I. Pigment Red 202 and the like, but are not limited thereto.

  Examples of yellow pigments include C.I. I. Pigment Yellow-1, C.I. I. Pigment Yellow-2, C.I. I. Pigment Yellow-3, C.I. I. Pigment Yellow-12, C.I. I. Pigment Yellow-13, C.I. I. Pigment Yellow-14, C.I. I. Pigment Yellow-16, C.I. I. Pigment Yellow-17, C.I. I. Pigment Yellow-73, C.I. I. Pigment Yellow-74, C.I. I. Pigment Yellow-75, C.I. I. Pigment Yellow-83, C.I. I. Pigment Yellow-93, C.I. I. Pigment Yellow-95, C.I. I. Pigment Yellow-97, C.I. I. Pigment Yellow-98, C.I. I. Pigment Yellow-114, C.I. I. Pigment Yellow-128, C.I. I. Pigment Yellow-129, C.I. I. Pigment Yellow-151, C.I. I. Pigment Yellow-154 and the like, but are not limited thereto.

In addition, for the present invention, a newly synthesized pigment may be used, or two or more pigments may be mixed and used.
In addition to the three primary color pigments of black and cyan, magenta, and yellow, specific color pigments such as red, green, blue, brown, and white, metallic luster pigments such as gold and silver, colorless extender pigments, and plastic pigments are used. May be. A particularly preferable pigment is carbon black.

  For these pigments, a known method or any of the newly invented methods can be used as a method for introducing a hydrophilic functional group on the surface of the pigment (surface modification treatment). For example, oxidation treatment with oxidizing agents (eg nitric acid, permanganate, dichromate, hypochlorite, ammonium persulfate, hydrogen peroxide, ozone, etc.), treatment with coupling agents such as silane compounds, polymer grafting In addition to known methods such as chemical treatment and plasma treatment, newly developed methods can also be used, and these methods may be combined.

  It is desirable to purify the obtained pigment with the hydrophilic functional group introduced by removing impurities such as the remaining oxidant, other inorganic impurities, and organic impurities. In particular, it is desirable that calcium, iron, and silicon in the ink be 10 ppm or less, preferably 5 ppm or less, respectively. In the present invention, the content of these inorganic impurities was measured by a high frequency inductively coupled plasma emission spectrometry. These impurities can be removed, for example, by washing with water, a reverse osmosis membrane, an ultrafiltration membrane, an ion exchange method or the like, or an adsorption method using activated carbon, zeolite or the like, alone or in combination.

  As the self-dispersible pigment into which these hydrophilic functional groups have been introduced, commercially available self-dispersible hydrophilic treated pigments can be used in addition to those newly prepared for the present invention. Examples of commercially available self-dispersible hydrophilic treatment pigments include MICROJET BLACK CW-1 (manufactured by Orient Chemical Industry Co., Ltd.), MICROJET BLACK CW-2 (manufactured by Orient Chemical Industry Co., Ltd.), CAB-O-JET200 ( Cabot Corporation), CAB-O-JET300 (Cabot Corporation), and the like. All of these commercially available self-dispersible hydrophilic pigments have a self-dispersibility index of 100%.

  The self-dispersible pigment is preferably contained in the range of 2 to 15% by mass with respect to the total mass of the ink, more preferably 3 to 10% by mass, and particularly preferably 4 to 8% by mass. When the pigment content exceeds 15% by mass, the possibility of nozzle clogging increases. On the other hand, if it is less than 2% by mass, the print density may be lowered.

-Pigment dispersed with resin The pigment used in the present invention is preferably also dispersed with resin as described above.
The pigment used for this is the same as the pigment before the introduction of the hydrophilic functional group listed in the description of the “self-dispersible pigment”.

  As the resin used as the pigment dispersant, nonionic compounds, anionic compounds, cationic compounds, amphoteric compounds and the like can be used, for example, copolymers of monomers having an α, β-ethylenically unsaturated group, etc. Can be used.

  Specifically, as a monomer having an α, β-ethylenically unsaturated group, acrylic acid, methacrylic acid, crotonic acid, itaconic acid, itaconic acid monoester, maleic acid, maleic acid monoester, fumaric acid, fumaric acid mono Ester, vinyl sulfonic acid, styrene sulfonic acid, sulfonated vinyl naphthalene, vinyl alcohol, acrylamide, methacryloxyethyl phosphate, bismethacryloxyethyl phosphate, methacryloxyethyl phenyl acid phosphate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, styrene, α -Styrene derivatives such as methylstyrene and vinyltoluene, vinylcyclohexane, vinylnaphthalene, vinylnaphthalene derivatives, alkyl acrylate, acrylic acid Glycol ester, methacrylic acid alkyl esters, methacrylic acid phenyl ester, methacrylic acid cycloalkyl ester, crotonic acid alkyl ester, itaconic acid dialkyl esters, maleic acid dialkyl ester and the like.

  A copolymer obtained by copolymerizing a single monomer or a plurality of monomers having the α, β-ethylenically unsaturated group is used as a dispersant. Specifically, polyvinyl alcohol, polyvinyl pyrrolidone, styrene-styrene sulfonic acid copolymer, styrene-maleic acid copolymer, styrene-methacrylic acid copolymer, styrene-acrylic acid copolymer, vinyl naphthalene-maleic acid copolymer. Polymer, vinyl naphthalene-methacrylic acid copolymer, vinyl naphthalene-acrylic acid copolymer, alkyl acrylate ester-acrylic acid copolymer, alkyl methacrylate-methacrylic acid, styrene-alkyl methacrylate-methacrylic acid copolymer Examples thereof include a polymer, a styrene-alkyl acrylate ester-acrylic acid copolymer, a styrene-methacrylic acid phenyl ester-methacrylic acid copolymer, and a styrene-methacrylic acid cyclohexyl ester-methacrylic acid copolymer.

  The resins as listed above added to the ink preferably have a mass average molecular weight in the range of 2000 to 15000. When the molecular weight of the polymer substance is less than 2,000, the pigment dispersibility may be lowered. On the other hand, when the molecular weight is more than 15,000, the viscosity of the ink may be increased and the dischargeability may be deteriorated. In addition, the more preferable mass average molecular weight of resin exists in the range of 3500-10000.

In the case of using a pigment dispersed by a resin, the content of the pigment in the ink is preferably in the range of 2 to 15% by mass for the same reason as in the case of the “self-dispersible resin”, and 3 to 10% by mass. Is more preferable, and 4 to 8% by mass is particularly preferable.
The content of the resin (dispersant) in the ink is preferably in the range of 0.1 to 3% by mass. When the addition amount exceeds 3% by mass, the ink viscosity increases, and the ink ejection characteristics may become unstable. On the other hand, when the addition amount is less than 0.1% by mass, the dispersion stability of the pigment may be lowered. Furthermore, the range of 0.15-2.5 mass% is more preferable, and the range of 0.2-2 mass% is especially preferable.

  Furthermore, in the case of an ink jet recording apparatus using black ink and color ink, it is particularly preferable to use black ink containing a self-dispersible pigment and color ink containing a pigment dispersed by a resin. . The color ink may be one using one color from cyan, magenta, yellow ink or the like, or may be one using a plurality of colors.

-Dye When using a dye as a coloring agent, a well-known thing or the newly synthesize | combined thing can be used, and it can also use together with the said pigment. Among these, a direct dye or an acid dye that can obtain a vivid color is preferable. Specific examples include the following:

Although it does not specifically limit as dye, Preferably it is a water-soluble dye. Examples of water-soluble dyes include acid dyes and direct dyes such as C.I. I. Direct Black-2, -4, -9, -11, -17, -19, -22, -32, -80, -151, -154, -168, -171, -194, -195, C.I. I. Food Black-1, -2, C.I. I. Acid Black-1, -2, -7, -16, -24, -26, -28, -31, -48, -52, -63, -107, -112, -118, -119, -121, -156, -172, -194, -208, C.I. I. Direct Blue-1, -2, -6, -8, -22, -34, -70, -71, -76, -78, -86, -112, -142, -165, -199, -200, -201, -202, -203, -207, -218, -236, -287, -307, C.I. I. Direct Red-1, -2, -4, -8, -9, -11, -13, -15, -20, -28, -31, -33, -37, -39, -51, -59, -62, -63, -73, -75, -80, -81, -83, -87, -90, -94, -95, -99, -101, -110, -189, -227, C.I. I. Direct violet-2, -5, -9, -12, -18, -25, -37, -43, -66, -72, -76, -84, -92, -107, C.I. I. Direct Yellow-1, -2, -4, -8, -11, -12, -26, -27, -28, -33, -34, -41, -44, -48, -58, -86, -87, -88, -132, -135, -142, -144, -173, C.I. I. Acid Red-1, -4, -8, -13, -14, -15, -18, -21, -26, -35, -37, -52, -110, -144. -180, -249, -257, C.I. I. Acid Yellow-1, -3, -4, -7, -11, -12, -13, -14, -18, -19, -23, -25, -34, -38, -41, -42, -44, -53, -55, -61, -71, -76, -78, -79, -122 and the like.
Particularly preferred dyes are C.I. I. Food Black-2, C.I. I. Direct black-154, -168, -195.

  When the dye is used, the content in the ink is preferably 0.1 to 10% by mass, more preferably 0.5 to 8% by mass, and particularly preferably 0.8 to 6% by mass. When the content is more than 10% by mass, clogging at the tip of the recording head tends to occur, and when the content is less than 0.1% by mass, a sufficient image density cannot be obtained.

-Other ingredients-

  Further, the ink in the present invention may contain an antioxidant, an antifungal agent, a conductive agent, an ultraviolet absorber, a chelating agent, and the like as necessary. As these additives, all conventionally known additives can be used. For example, as a chelating agent, ethylenediaminetetraacetic acid (EDTA), iminodiacetic acid (IDA), ethylenediamine-di (o-hydroxyphenylacetic acid) (EDDDHA). ), Nitrilotriacetic acid (NTA), dihydroxyethylglycine (DHEG), trans-1,2-cyclohexanediaminetetraacetic acid (CyDTA), diethylenetriamine-N, N, N ′, N ″, N ″ -pentaacetic acid (DTPA) Glycol ether diamine-N, N, N ′, N′-tetraacetic acid (GEDTA) and the like.

  Further, a surfactant can be added in order to adjust the surface tension of the ink in the present invention. As the surfactant, nonionic and anionic surfactants that do not easily affect the dispersion state of the pigment are preferable. Nonionic surfactants include, for example, polyoxyethylene nonyl phenyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene dodecyl phenyl ether, polyoxyethylene alkyl ether, polyoxyethylene fatty acid ester, sorbitan fatty acid ester, polyoxyethylene sorbitan Fatty acid esters, fatty acid alkylolamides, acetylene alcohol ethylene oxide adducts, polyethylene glycol polypropylene glycol block copolymers, glycerin ester polyoxyethylene ethers, sorbitol ester polyoxyethylene ethers, and the like can be used.

  Examples of anionic surfactants include alkylbenzene sulfonates, alkylphenyl sulfonates, alkylnaphthalene sulfonates, higher fatty acid salts, sulfate esters of higher fatty acid esters, sulfonates, and higher alkyl sulfosuccinates. Can be used.

  Further, as the amphoteric surfactant, betaine, sulfobetaine, sulfate betaine, imidazoline and the like can be used. In addition, silicone surfactants such as polysiloxane polyoxyethylene adducts, fluorine surfactants such as oxyethylene perfluoroalkyl ether, biosurfactants such as splicrisporic acid, rhamnolipid, and lysolecithin can also be used.

  When the surfactant is included, it is preferable to select at least one from a nonionic surfactant and an anionic surfactant.

  In addition, as a method of adjusting the surface tension of the ink, there is a method of containing a polyhydric alcohol, a monohydric alcohol, or the like in addition to the inclusion of the surfactant. The total content of the compounds in the ink is preferably in the range of 0.01 to 3.0% by mass, more preferably in the range of 0.03 to 2.0% by mass, and 0.05 More preferably, it is in the range of -1.5% by mass. In particular, when the surfactant is used alone, the content is preferably in the range of 0.3 to 1.5% by mass.

  The surface tension of the ink adjusted by the above method is preferably adjusted in the range of 20 to 37 mN / m, more preferably in the range of 25 to 37 mN / m. When the surface tension is less than 20 mN / m, the ink permeability to the recording paper is too fast, the show-through density increases, and the suitability for double-sided printing may deteriorate. On the other hand, if it is larger than 37 mN / m, the ink permeability to the recording paper becomes slow, so that the drying property is deteriorated, and it becomes impossible to cope with high-speed printing, and the productivity may be lowered.

  In addition to methyl cellulose, ethyl cellulose and derivatives thereof, glycerins and polyglycerin and polyethylene oxide and polypropylene oxide adducts thereof, and addition of polysaccharides and derivatives thereof as viscosity modifiers in the ink of the present invention is also a preferred embodiment. . Examples of the viscosity modifier include glucose, fructose, mannitol, D-sorbitol, dextran, xanthan gum, curdlan, cycloamylose, maltitol and derivatives thereof.

  The viscosity of the ink in the invention is preferably in the range of 1 to 8 mPa · s (cP) at 20 ° C., more preferably in the range of 2 to 5 mPa · s (cP). If it is greater than 8 mPa · s (cP), the ejection becomes unstable, which is not desirable. On the other hand, the case of less than 1 mPa · s (cP) is not desirable because ejection stability cannot be obtained.

  The ink of the present invention can be adjusted for pH as necessary. Examples of components for adjusting pH include potassium hydroxide, sodium hydroxide, lithium hydroxide, ammonium hydroxide, triethanolamine, diethanolamine, ethanolamine, 2-amino-2-methyl-1-propanol, ammonia, and phosphoric acid. Ammonium, potassium phosphate, sodium phosphate, lithium phosphate, sodium sulfate, acetate, lactate, benzoate, acetic acid, hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, propionic acid, P-toluenesulfonic acid, etc. . Alternatively, a general pH buffer can be used.

  Although not particularly limited, the pH range of the ink in the present invention is preferably about 3 to 11, more preferably about 4.5 to 9.5. In addition, in an ink having an anionic free radical on the pigment surface, the pH is preferably about 6 to 11, more preferably about 6 to 9.5, and still more preferably about 7.5 to 9.0. On the other hand, in an ink having a cationic free radical on the pigment surface, the pH is preferably about 4.5 to 8.0, more preferably about 4.5 to 7.0.

-Preparation method of ink-
An example of the ink preparation method is shown below.
When the ink used in the ink jet recording apparatus of the present invention is an ink using a pigment dispersed with the resin, for example, a predetermined amount of the pigment is added to an aqueous solution containing a predetermined amount of the resin (dispersant). Then, after sufficiently stirring, disperse using a disperser, remove coarse particles by centrifugation or the like, add the predetermined water-soluble organic solvent, the additive, etc., stir and mix, and then filter. Can be obtained by going. At this time, it is also possible to use a method in which a concentrated dispersion of pigment is prepared in advance and diluted when preparing ink. In addition, a pigment pulverization step may be provided before the dispersion step. Alternatively, after mixing a predetermined water-soluble organic solvent, water, and a dispersant, a pigment may be added and dispersed using a disperser.

  A commercially available dispersing machine can be used. For example, colloid mill, flow jet mill, slasher mill, high speed disperser, ball mill, attritor, sand mill, sand grinder, ultra fine mill, Eiger motor mill, dyno mill, pearl mill, agitator mill, cobol mill, 3 rolls, 2 rolls Examples thereof include a roll, an extruder, a kneader, a microfluidizer, a laboratory homogenizer, and an ultrasonic homogenizer. These may be used alone or in combination of two or more. In order to prevent mixing of inorganic impurities, it is preferable to use a dispersion method that does not use a dispersion medium. In that case, it is preferable to use a microfluidizer, an ultrasonic homogenizer, or the like.

  On the other hand, in the case of an ink using the self-dispersible pigment as the pigment, for example, the surface modification treatment is performed on the pigment, the obtained pigment is added to water, and the mixture is sufficiently stirred. It can be obtained by dispersing with the same disperser as described above, removing coarse particles by centrifugation or the like, then adding a predetermined solvent, additive, etc., stirring, mixing, and filtering.

(Inkjet recording head)
-Structure of recording head The ink jet recording head in the present invention is composed of a plurality of members made of metal and / or resin, and satisfies the point that a polyimide-based adhesive is used for an adhesive portion between at least one member. Any known recording head may be used.
Here, FIG. 1 schematically shows an example of an ink jet recording head that can be used in the present invention.

  As shown in FIG. 1, the inkjet recording head 110 includes a substrate 140 on which an ink supply port 144 is formed in the longitudinal direction. One surface of the substrate 140 is covered with an insulating layer 142, and the heating resistor element 124 is provided on the other surface. The heating resistor element 124 is housed in the first ink chamber 162 formed by the first adhesive portion 160. In addition, a second ink chamber 164 formed by a partition wall 128 and a second adhesive portion 166 is provided in the upper portion of the first ink chamber 162. The first ink chamber 162 and the second ink chamber 164 are combined to form an ink chamber 122. An ink discharge port 120 is formed in the orifice plate 126 corresponding to the ink chamber 122. In the orifice plate 126, a reinforcing wall 130 standing toward the ink supply port 144 is extended along the ink supply port 144.

  Here, an ink droplet ejection mechanism will be described. After ink in an ink tank (not shown) is filled from the ink supply port 144 into the ink chamber 122 and the ink discharge port 120, the heating resistor element 124 is heated, and the ink filled in the ink chamber 122 is boiled by this heat generation. Ink droplets are ejected from the ink ejection port 120 by the pressure of bubbles generated in the ink. After the ink droplet is ejected, the ink chamber 122 and the ink ejection port 120 are filled with ink again to prepare for the ejection of the next ink droplet.

  In the recording head shown in FIG. 1, examples of materials used for the respective members include silicon for the substrate 140, epoxy for the partition wall 128, and stainless steel for the orifice plate 126, and a first adhesive portion between the substrate 140 and the partition 128. 160 and the second adhesive portion 166 between the partition wall 128 and the orifice plate 126 may be configured using an adhesive. Of course, the present invention is not limited to these configurations, and may satisfy the requirements of the recording head in the present invention. Preferably, the material of the metal member is stainless steel, nickel / cobalt alloy, silicon, resin member. Examples of the material include polyimide, epoxy, and polyurethane. Furthermore, it is preferable to use at least one of these materials.

In addition, the recording head used in the present invention is not limited to the thermal ink jet method described with reference to FIG. 1. For example, a so-called charge control method in which ink is ejected using electrostatic attraction, and the vibration pressure of the piezo element is set. A recording head that employs any known method such as a so-called pressure pulse method that ejects ink by using it may be used.
Next, the adhesive will be described.

· In the adhesives present invention, the ink jet recording head, it is essential to use a polyimide-based adhesive having a glass transition point of 100 to 190 ° C.. Use of the ink in the present invention, which uses a polyimide-based adhesive having a glass transition point in the range of 100 to 190 ° C. and contains a desired amount of a water-soluble solvent having a dispersion force term value in a desired range of the solubility parameter. As a result, it is possible to prevent the deterioration of the adhesive and to realize an ink jet recording apparatus that does not shorten the life of the head. Also, if the glass transition point is high, abnormalities such as warpage tend to occur at the time of curing of the adhesive, and high-precision bonding cannot be realized, and there is a concern about the impact on the ejection stability of ink droplets. However, the adhesive in the present invention having a glass transition point in the range of 100 to 190 ° C. has no problem. When the glass transition point is low, it is advantageous for an adhesion-only process, but it is often not preferable in consideration of a process for combining other members constituting the head.
In addition, as for the glass transition point of an adhesive agent, 120-190 degreeC is more preferable.

As the adhesive used in the present invention is not particularly limited as long as it satisfies the above requirements, polyimide-based adhesive is used. Polyimide adhesives have the advantage of having an aromatic rigid structure and excellent heat resistance. Especially, the thermal expansion coefficient is close to that of metal, and when used as an adhesive with metal, deformation due to heating is suppressed. High-precision joining is possible.

  In addition, the polyimide adhesive which can be used for this invention has the following structures.

  In the general formula (1), X represents at least one selected from the following compounds (2) to (6).

  In the general formula (1), Y represents a mixture of at least one selected from the following compounds (7) to (8) and the following compound (9).

Wherein, R ₁ is a divalent hydrocarbon group having 1 to 6 carbon atoms, also, n is an integer of from 1 to 20. Adhesives having different glass transition points can be obtained by appropriately combining these constituent units.

(Inkjet recording device)
Hereinafter, an embodiment of an ink jet recording apparatus of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and redundant description is omitted.
FIG. 2 is a perspective view showing an external configuration of an embodiment of the ink jet recording apparatus according to the present invention. FIG. 3 is a perspective view showing the basic internal configuration of the ink jet recording apparatus of FIG. The ink jet recording apparatus 100 of the present embodiment has a configuration that operates based on the ink jet recording method of the present invention described later and records an image. That is, as shown in FIGS. 2 and 3, the inkjet recording apparatus 100 mainly includes an external cover 6, a tray 7 on which a predetermined amount of recording paper 1 such as plain paper can be placed, and the recording paper 1 as an inkjet recording apparatus. The image forming apparatus 100 includes a conveyance roller (conveyance unit) 2 for conveying the sheet 100 inside one by one, and an image recording unit 8 (image recording unit) that records an image by ejecting ink onto the surface of the recording paper 1. .

  The conveyance rollers 2 are a pair of rollers rotatably disposed in the ink jet recording apparatus 100, sandwiching the recording paper 1 set on the tray 7 and one sheet of a predetermined amount of recording paper 1 at a predetermined timing. Each time it is transported into the apparatus 100.

  The image recording unit 8 records an image with ink on the surface of the recording paper 1. The image recording unit 8 mainly includes a recording head 3, an ink tank unit 5, a power supply signal cable 9, a carriage 10, a guide rod 11, a timing belt 12, a drive pulley 13, and a maintenance unit 14. ing.

  The ink tank unit 5 includes ink tank units 52, 54, 56, and 58 in which different colors of ink are stored so as to be ejected. Here, the recording head 3 and the ink tank unit 5 are a black ink recording head and a black ink ink tank that eject (eject) black ink, and a color ink recording head and color ink that eject (eject) color ink. And an ink tank.

  Further, as shown in FIG. 3, a power feeding signal cable 9 and an ink tank unit 5 are connected to the recording head 3, and when external image recording information is input from the power feeding signal cable 9 to the recording head 3, recording is performed. The head 3 sucks a predetermined amount of ink from each ink tank based on the image recording information and discharges the ink onto the surface of the recording paper. The power supply signal cable 9 also has a role of supplying power necessary for driving the recording head 3 to the recording head 3 in addition to the image recording information.

  The recording head 3 is arranged and held on a carriage 10, and the carriage 10 is connected to a guide rod 11 and a timing belt 12 connected to a driving pulley 13. With such a configuration, the recording head 3 extends along the guide rod 11 and is parallel to the surface of the recording paper 1 on which the powder is dispersed, and with respect to the conveyance direction X (sub-scanning direction) of the recording paper 1. It is also possible to move in the vertical direction Y (main scanning direction). That is, when the driving pulley 13 is rotated at a predetermined timing based on the image recording information, the carriage 10 on which the recording head 3 is mounted is driven along the guide rod 11 via the timing belt 12, that is, the carriage 10 reciprocates in the direction Y (main scanning direction) perpendicular to the conveyance direction X (sub-scanning direction) of the recording paper 1, thereby recording an image in a predetermined area on the surface of the recording paper 1.

  The ink jet recording apparatus 100 includes a control unit (not shown) that adjusts the drive timing of the recording head 3 and the drive timing of the carriage 10 based on image recording information. Thereby, an image based on the image recording information can be continuously recorded in a predetermined area on the surface of the recording paper 1 conveyed at a predetermined speed along the conveyance direction X.

  The maintenance unit 14 is connected to a decompression device (not shown) through the tube 15. Further, the maintenance unit 14 is connected to the nozzle portion of the recording head 3 and has a function of sucking ink from the nozzles of the recording head 3 by reducing the pressure inside the nozzles of the recording head 3. By providing this maintenance unit 14, if necessary, excess ink adhering to the nozzles during operation of the inkjet recording apparatus 100 is removed, or evaporation of ink from the nozzles is suppressed when the operation is stopped. be able to.

<Inkjet recording method>
The inkjet recording method of the present invention comprises a plurality of members made of metal and / or resin, and at least a colorant and a water-soluble substance from a recording head using an adhesive at an adhesive portion between at least one member. An ink jet recording method for recording an image by discharging an ink containing an organic solvent and water onto a recording medium, the glass transition point of the adhesive, the solubility parameter (SP value) of the water-soluble organic solvent ) And the content of the water-soluble organic solvent in the ink are specific values. Further, preferable conditions of the ink to be used and other conditions are also as described in the above-described ink jet recording apparatus of the present invention.

  Any conventionally known transport means, ink jet recording head, and image signal input means in the ink jet recording method of the present invention can be used. The effect of the invention is exhibited without any limitation. In other words, any so-called ink jet recording method can achieve excellent ink ejection stability without shortening the life of the recording head, and can perform high-speed printing.

An ink-jet recording method having a function of accelerating print fixing by heating a recording medium and ink at 50 ° C. to 200 ° C. at the time of printing or before and after printing can be used, or plain paper, glossy paper, special paper In addition to direct printing on cloth, film, OHP, etc., printing is performed on an intermediate body such as an intermediate drum or belt, and an ink image is prepared on the intermediate body and then transferred and recorded on paper, cloth, film, etc. It may be a method.
In addition to the ink used in the present invention, the present invention can also be applied to a so-called two-component ink jet recording system in which colorless or light ink is used and mixed with the ink of the present invention on paper.

EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to these Examples. In the examples, “parts” represents “parts by mass” unless otherwise specified. Of the examples shown below, Examples 4, 47 to 52, 71 to 76, 95 to 100, and 119 to 124 using epoxy adhesives are shown as reference examples.

<Evaluation of adhesive>
Example 1
With an adhesive having a glass transition point (Tg) of 100 ° C., two stainless steel plates (one of which has a hole for observation of the adhesive surface on one side) were laminated and cured. The shape change of the bonded members after curing was observed.
○: No abnormality is found ×: Abnormality such as warping

As the adhesive having a Tg of 100 ° C., in the general formula (1), X is the compound (5), Y is the compound (7), and R ₁ in the compound (9) has 3 carbon atoms, n = 1 A polyimide-based adhesive having a mass ratio of compound (7) :( 9) of 15:35 was used.

-Examples 2-4, Comparative Example 1-
The adhesive was evaluated in the same manner as in Example 1 except that the adhesive used in Example 1 was changed to that shown in Table 1, respectively.
The results are shown in Table 1.

In Example 2, as an adhesive having a Tg of 120 ° C., in the general formula (1), X is the compound (5), Y is the compound (8), and the carbon number of R ₁ in the compound (9) is 3, n = 1, and a polyimide-based adhesive having a mass ratio of the compound (8) :( 9) of 15:35 was used.

In Example 3, as an adhesive having a Tg of 190 ° C., in the general formula (1), X is the compound (5), Y is the compound (8), and R ₁ in the compound (9) has 3 carbon atoms, A polyimide-based adhesive in which n = 1 and the mass ratio of the compound (8) :( 9) was 20:30 was used.

  In Example 4, as an adhesive having a Tg of 130 ° C., 100 parts of a bisphenol A-diglycidyl ether epoxy resin (main agent) and 20 parts of a 1: 1 mixture (curing agent) of phenylphosphonic acid and o-phenylenediamine were added. A mixed epoxy adhesive was used.

In Comparative Example 1, as an adhesive having a Tg of 240 ° C., in the general formula (1), X is the compound (5), Y is the compound (8), and R ₁ in the compound (9) has 3 carbon atoms, A polyimide-based adhesive in which n = 1 and the mass ratio of the compound (8) :( 9) was 35:15 was used.

<Evaluation of ink permeability>
-Example 5
First, a black ink for ink jet recording was prepared with the following composition.
Carbon black (CaboJet 300 / colorant manufactured by Cabot Corporation) 5 parts 1,2-hexanediol (water-soluble organic solvent) 10 parts Nonionic surfactant 1 part Glycerin 10 parts Water Total balance 100 parts Inkjet printer PM-970C (Seiko) Epson Co., Ltd.) is used to perform solid printing at a resolution of 720 × 360 dpi on plain paper (manufactured by Fuji Xerox Co., Ltd./multi-ace paper), and another plain paper is placed on the printing section at a weight of 100 g / cm ² The time when transfer was stopped was measured.
○: No transfer within 2 seconds Δ: No transfer within 2 seconds ×: Transfer occurs even after 2 seconds have passed Note that Table 2 shows the dispersion power of the SP value of the water-soluble organic solvent used in this example. The term (δd) and other values (SP value, δp, δh) are shown.

-Examples 6-10, Comparative Examples 2-5
Ink permeability was evaluated in the same manner as in Example 5 except that the water-soluble organic solvents used in Example 5 were changed to those shown in Table 3, respectively. In Comparative Example 2, the content of the water-soluble organic solvent (glycerin) is 20 parts.

-Examples 11-28, Comparative Examples 6-17-
Ink permeability was evaluated in the same manner as described above except that the contents of the water-soluble organic solvents used in Examples 5 to 10 and Comparative Examples 2 to 5 were changed to the amounts shown in Table 3, respectively. In Comparative Examples 6, 10, and 14, the content of the water-soluble organic solvent (glycerin) is 18 parts, 14 parts, and 12 parts, respectively.
The results are shown in Table 3.

In Table 2 and Tables 3-7 below,
DEGmEE: diethylene glycol monoethyl ether TEGmBE: triethylene glycol monobutyl ether DEGmBE: diethylene glycol monobutyl ether DEGiBE: diethylene glycol isobutyl ether PGmEE: propylene glycol monoethyl ether DEG: diethylene glycol TEG: triethylene glycol PGmME: propylene glycol monomethyl ether

<Degradation evaluation of adhesive>
-Example 29-
In the ink prepared in Example 5, a member (similar to the member prepared in Example 1) obtained by bonding two stainless steel plates with a polyimide adhesive having a glass transition point (Tg) of 100 ° C. And heated at 70 ° C. for 300 hours. The state of the adhesive after heating was observed.
◎: No abnormality is observed. ○: The surface is rough but does not peel. Δ: The surface is discolored but does not peel.

-Examples 30-124, Comparative Examples 18-121-
Example 29, except that the conditions of the water-soluble organic solvent used in Example 29, its content, and the adhesive for bonding two stainless steel plates were changed to those shown in Tables 4 to 7, respectively. Ink permeability was evaluated in the same manner as described above. The content when glycerin is used as the water-soluble organic solvent is as described in the table.
The results are shown in Tables 4-7.

  Even when the colorant was changed from carbon black to CI pigment yellow 128 (acrylic-styrene copolymer emulsion dispersion), there was no difference in the results.

  From the results of adhesive evaluation, ink permeability evaluation, and adhesive deterioration evaluation performed in this example, the ink used in the present invention has high-speed drying (high permeability), and high-speed printing is possible. In addition, it was found that the adhesive that is a constituent of the recording head has no problem of occurrence of abnormality such as warpage during curing, and at the same time, deterioration due to contact with ink can be effectively prevented. From these, according to the present invention, it can be said that it is possible to provide an ink jet recording apparatus having a long recording head life, excellent ink ejection stability, and capable of high-speed printing, and an ink jet recording method using the same. .

1 is a partial cross-sectional perspective view schematically showing an ink jet recording head according to an embodiment of the present invention. 1 is a perspective view illustrating an external configuration of an embodiment of an ink jet recording apparatus according to the present invention. FIG. 3 is a perspective view showing an internal basic configuration of the ink jet recording apparatus of FIG. 2.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Recording paper 2 Conveyance roller 3 Recording head 5 Ink tank unit 6 External cover 7 Tray 8 Image recording part 9 Power supply signal cable 10 Carriage 11 Guide rod 12 Timing belt 13 Drive pulley 14 Maintenance unit 15 Tube 52, 54, 56, 58 Ink Tank unit 100 Inkjet recording apparatus 110 Inkjet recording head 120 Ink discharge port 122 Ink chamber 124 Heating resistance element 126 Orifice plate 128 Partition 130 Reinforcing wall 140 Substrate 142 Insulating layer 144 Ink supply port 160 First adhesive portion 162 First ink chamber 164 First 2 ink chamber 166 2nd adhesion part

Claims (1)

It is composed of a plurality of members made of metal and / or resin, and has a recording head using a polyimide-based adhesive in the adhesive portion between the at least one member, shown further, at least, a coloring agent, the following and one water-soluble organic solvent of the group, and water, only contains, and the an ink jet recording apparatus using one kind of ink that does not contain a water-soluble organic solvent other than the water-soluble organic solvent, the adhesive the glass transition point of the agent is the 100 to 190 ° C., and the a value of dispersion force term of one water-soluble organic solvent soluble Kaido parameter (SP value) of 15.8 to 17.1, its an ink jet recording apparatus amount contained in the water-soluble organic inks of the solvent, characterized in that 2 to 10 wt%.
Group: Ethylene glycol monomethyl ether
Ethylene glycol monoethyl ether
Ethylene glycol monobutyl ether
Diethylene glycol monomethyl ether
Diethylene glycol monoethyl ether
Diethylene glycol monobutyl ether
Propylene glycol monobutyl ether
Triethylene glycol monobutyl ether
1,2-hexanediol
Diethylene glycol isobutyl ether
Propylene glycol monoethyl ether

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