JP2003137910A - Method for producing colored resin particulate, method for producing aqueous dispersion of the colored resin particulate, the colored resin particulate, ink, recording unit, ink cartridge, ink jet recording unit and method for ink jet recording - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain colored resin particulates imparting an image having water resistance, weatherability, especially abrasion resistance and excellent in dispersion stability, particularly useful as ink colorant and provide a method for producing the colored resin particulates by which the colored resin particulates having a uniform small particle size are easily obtained or a method for producing an aqueous dispersion of the colored resin particulates. SOLUTION: This method for producing the colored resin particulates includes (i) a process in which an aqueous medium is added to an oil phase containing at least a polymerizable unsaturated monomer, an emulsifier and a polymerization initiator and the ingredients are dispersed in the aqueous medium and (ii) a process in which the polymerizable unsaturated monomer is polymerized. The method is to use pigment-dispersed water as the aqueous medium in the process (i) and emulsify by phase transfer emulsification. The colored resin particulates, an ink using the colored resin particulates, an ink jet recording device and the like are disclosed.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a colored resin fine particle which, when contained in an ink, gives an image excellent in water resistance and weather resistance, particularly scratch resistance, and also has excellent dispersion stability. The manufacturing method is related. Further, the present invention relates to a method for producing an aqueous dispersion of colored resin fine particles which, when contained in an ink, gives an image excellent in water resistance and weather resistance, particularly excellent in scratch resistance, and is also excellent in dispersion stability. . Further, the present invention relates to an ink which gives an image excellent in water resistance and weather resistance, particularly scratch resistance, has excellent dispersion stability, and is also excellent in ejection stability from a recording head when used for inkjet recording. . The present invention also relates to an ink jet recording apparatus that gives an image excellent in water resistance and weather resistance, particularly scratch resistance, and an ink cartridge and a recording unit that can be used for the same. Further, the present invention relates to an inkjet recording method capable of obtaining an image excellent in water resistance and weather resistance, particularly scratch resistance.

[0002]

2. Description of the Related Art An ink jet recording method is one in which recording is performed by ejecting ink and adhering the ink to a recording medium such as paper. For example, Japanese Patent Publication No. 61-59911, Japanese Patent Publication No. 61-59912 and Japanese Patent Publication No. 61-5.
According to the ink jet recording method disclosed in Japanese Patent No. 9914, in which an electrothermal converter is used as the ejection energy supply means and thermal energy is applied to ink to generate bubbles to eject droplets, a recording head is provided. High density multi-orifice can be easily realized, and high resolution and high quality images can be recorded at high speed.

By the way, a water-soluble dye, for example, is used as a coloring material in the ink used in the conventional ink jet recording method, and the recorded image by such ink is further improved in water resistance. Is required. Further, water-soluble dyes up to now have insufficient weather resistance, and improvement in weather resistance is also required at the same time.

On the other hand, as a means for improving water resistance and weather resistance, there is a technique of using a pigment as a coloring material and dispersing it in water to prepare an ink. However, it is difficult to achieve both the dispersion stability of the pigment and the ejection stability of the inkjet recording, and the recorded image obtained by the pigment ink has a water-soluble dye ink that is particularly scratch-resistant on plain paper. It is inferior and there is room for improvement.

Many means for improving such problems have been proposed so far. For example, many techniques for adding a resin to a pigment ink have been proposed for the purpose of improving scratch resistance. However, there remains a problem that the viscosity of the ink increases due to the added resin. A technique has been proposed in which resin particles are added for the purpose of suppressing an increase in the viscosity of the ink, but since this ink is in a state in which the resin particles and the pigment are separately dispersed, the scratch resistance of the obtained image is improved. The improvement was inadequate.

On the other hand, a technique of coating the surface of the pigment particles with a resin has been proposed. A number of techniques have been proposed which attempt to improve the adsorptivity of the resin to the pigment by controlling the hydrophobic part and the hydrophilic part of the resin. But,
In this production method, the resin which is not adsorbed to the pigment and remains floating in the system may cause an increase in viscosity or impair the ink ejection property.

As a manufacturing method in which such a free resin does not remain in the ink, a pigment is added from the stage of the monomer before the resin is prepared, and polymerization is performed in the presence of the pigment to coat the pigment particles with the resin. The technology to do is proposed. For example, Japanese Unexamined Patent Publication No. 9-279073 discloses a technique of adding a coloring agent having an affinity to the unsaturated monomer and emulsion-polymerizing the resin to obtain colored resin fine particles.
Japanese Laid-Open Patent Publication No. 1-112512 discloses a technique of adding a pigment to an ethylenically unsaturated monomer and performing emulsion polymerization to obtain an inkjet recording liquid.

[0008]

However, according to the studies by the present inventors, it is very difficult to obtain dispersion stability at the time of emulsifying the unsaturated monomer and the pigment,
At this point, if the dispersion stability was insufficient, it was feared that the obtained dispersion would also have low stability. For example, according to the description of the specification, the colored resin particles described in JP-A-9-279073 described above can be manufactured according to a conventional emulsion polymerization method, and also in Examples. After mixing the monomer and colorant, emulsify the water as it is with the emulsifier added,
It is produced by carrying out emulsion polymerization.

However, according to the studies by the present inventors, in the above-mentioned method, the polymerization proceeds while the mixed solution of the monomer and the colorant is sheared, so that the particle size varies due to the difference in shearing. It was speculated that it would be difficult to obtain colored resin particles having a small particle size and being highly homogenized by this method. Further, Japanese Patent Laid-Open No. 11-12512 discloses that
When emulsion polymerization is carried out for the purpose of obtaining an inkjet ink, a method of forming monomer oil droplets of 0.5 μm or less using a pipeline mixer or the like is described. However, according to the study by the present inventors, it is difficult to narrow the distribution of particle size only by mechanical dispersion, and when a strong mechanical shearing force is given, the particle size is stable over time. It was speculated that the sex would be impaired.

As described above, the inventors of the present invention have studied the conventional techniques, and further improve not only water resistance and weather resistance but also scratch resistance and further dispersion stability and ejection stability in ink jet inks. In order to achieve this, we have come to the conclusion that a new technological development different from the previous one is necessary. On the other hand, as a result of repeated studies by the present inventors, a conventional colored resin that can provide colored resin fine particles that can maximize the advantages of using colored resin fine particles as a coloring material of ink The present invention has been accomplished by finding out a technique capable of solving the problems of the method for producing fine particles.

Therefore, an object of the present invention is to provide a colored resin fine particle which, when applied to an ink, gives an image having water resistance and weather resistance, particularly scratch resistance, and is excellent in dispersion stability.
Another object is to provide an aqueous dispersion of colored resin particles and a method for producing the same. Further, the present invention provides an image having water resistance and weather resistance, particularly scratch resistance, and is excellent in dispersion stability,
It is a point to provide an ink excellent in ejection stability from a recording head when used for inkjet recording. Further, an object of the present invention is an ink jet recording apparatus which gives an image excellent in water resistance and weather resistance, particularly scratch resistance, and an ink cartridge and a recording unit which can be used for the same, further, water resistance and weather resistance, particularly Another object of the present invention is to provide an inkjet recording method capable of obtaining an image having excellent scratch resistance.

[0012]

The above object can be achieved by the present invention described below. That is, one embodiment of the present invention is
(I) a step of adding an aqueous medium to an oil phase containing at least a polymerizable unsaturated monomer, an emulsifier and a polymerization initiator, and emulsifying the above components in the aqueous medium; and (ii) the polymerizable unsaturated monomer. A method for producing colored resin fine particles, which comprises a step of polymerizing a monomer, wherein in the step (i), water in which a pigment is dispersed is used as an aqueous medium, and emulsification is performed by a phase inversion emulsification method. Is a method for producing fine colored resin particles. That is, in the above aspect, the polymerizable unsaturated monomer, the emulsifier and the polymerization initiator are emulsified in an aqueous medium by a phase inversion emulsification method,
In a method of polymerizing the same to produce resin fine particles, water in which a pigment is dispersed is used as an aqueous phase for phase inversion emulsification in which an oil phase is inverted to an aqueous phase.

Further, as a more preferable embodiment of the above, there is a method of producing colored resin fine particles further containing a coloring agent in the oil phase in the step (i). According to such a method, it is possible to obtain colored resin fine particles containing a higher concentration of colorant, and by using such colored resin fine particles, an ink giving an image of high color density can be obtained.

Another aspect of the present invention is to add an aqueous medium to an oil phase containing (i) a polymerizable unsaturated monomer, an emulsifier and a polymerization initiator, and emulsify the above components in the aqueous medium. And (ii) a step of polymerizing the polymerizable unsaturated monomer, which is a method for producing an aqueous dispersion of colored resin fine particles, wherein in the step (i), water in which a pigment is dispersed as an aqueous medium is used. Is used to perform emulsification by the phase inversion emulsification method. Further, another embodiment of the present invention is to add (i) an aqueous medium consisting of water in which a pigment is dispersed in an oil phase containing a polymerizable unsaturated monomer, an emulsifier and a polymerization initiator, and add the above components to an aqueous solution. A step of emulsifying in a medium by a phase inversion emulsification method; (ii) a step of polymerizing the polymerizable unsaturated monomer; and (iii) an aqueous dispersion of the colored resin fine particles obtained by the steps (i) and (ii). A method for producing colored resin fine particles, which comprises the step of removing water from the body.

Another aspect of the present invention is an ink containing the colored resin fine particles produced by any one of the above-mentioned methods and a liquid medium, and further, the ink is an inkjet. For example, the ink is for use. The dispersion of colored resin fine particles obtained by the method described above is excellent in dispersion stability, and according to the ink using this,
An image with water resistance and weather resistance, especially scratch resistance is obtained,
In addition, the ink has excellent dispersion stability, and when used in inkjet recording, has excellent ejection stability.

According to another aspect of the present invention, there is provided a recording unit characterized by comprising an ink containing portion containing the above ink, and a head portion for discharging the ink. An ink cartridge comprising an ink containing portion containing ink, an ink containing portion containing the above ink, and a recording head for ejecting the ink. An inkjet recording device characterized by the above, and an inkjet recording method characterized by comprising a step of ejecting the above ink by an inkjet method.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail below with reference to preferred embodiments. A method for producing colored resin fine particles according to one aspect of the present invention is a method for obtaining fine particles by emulsifying a polymerizable unsaturated monomer and an emulsifier in an aqueous medium, and then polymerizing the polymerizable unsaturated monomer. However, in the above emulsification step, the first feature is to use a phase inversion emulsification method in which the phase of an oil containing a polymerizable unsaturated monomer is inverted to the aqueous phase, and at that time, a pigment is added. The second feature is that the dispersed water is added to the oil phase to carry out phase inversion emulsification. First, this will be described.

As an emulsification method, generally, an emulsifier is added to water, an oil component is added to the mixture, and the mixture is stirred with a disperser (hereinafter referred to as a direct emulsification method), or an emulsifier is added to the oil component. A method in which this is placed in a large amount of water (hereinafter referred to as a natural emulsification method) and a phase inversion emulsification method are included. The direct emulsification method is a method in which a strong shearing force is applied using a disperser to pulverize and emulsify emulsion particles, and an emulsion can be obtained relatively easily. However, if the emulsion particles are not evenly sheared, the particle size distribution will become wider, and the more time a strong shearing force is applied in order to obtain particles with a small particle size, the longer time stability. Is known to be compromised. Further, the natural emulsification method has an advantage that it is emulsified just by adding it to water, but it requires a high degree of specialized knowledge in selecting an emulsifier and cannot be applied to all substances.

On the other hand, the phase inversion emulsification method used in the present invention is a method of emulsifying by gradually adding water to a liquid oil phase (oils) added with an emulsifier while stirring. When water droplets are added to the oil phase, a W / O type emulsion is initially formed, the viscosity increases as the amount of water increases, and then the phase is changed to the O / W type emulsion. The feature of the phase inversion emulsification method is that it passes through this phase inversion point. In such a phase inversion emulsification method, at the phase inversion point at which the particles and the continuous layer in which the particles are dispersed are replaced with each other, sufficient shearing force is applied to stir to agitate the emulsion so that the particle size distribution is very narrow and uniform. Is obtained. It is also known that the emulsion obtained by the phase inversion emulsification method as described above is particularly excellent in dispersion stability.

The phase inversion emulsification method is generally carried out manually by using a beaker and a stirring rod, but in the present invention, if the stirring at the phase inversion point is more powerful and uniform, Since it is possible to obtain a more uniform emulsion having a small particle size,
It is preferable to use a disperser in the emulsification step. Examples of the disperser used at this time include a three-one motor, a homomixer, and a homogenizer. In this way, by adding mechanical dispersion force to the phase inversion emulsification method,
It is possible to obtain an emulsion having a narrow particle size distribution and a small particle size, which is not obtained by the conventional direct emulsification method, and particularly excellent in dispersion stability.

Further, the second feature of the present invention is to use a pigment dispersion liquid in which a pigment is dispersed in water as an aqueous phase to be added to the oil phase when the above-mentioned phase inversion emulsification is carried out. On the other hand, when the phase inversion emulsification is performed by adding water little by little to the oil phase in which the pigment is previously dispersed in the polymerizable unsaturated monomer, the pigment is added to the polymerizable unsaturated monomer in a high concentration. In order to uniformly disperse at a concentration, an advanced dispersion technique and an expensive dispersion device are required. On the other hand, according to the method of the present invention,
By using a pigment dispersion liquid in which primary particles are obtained by a simple process of uniformly dispersing an aqueous pigment in water, an emulsion having the above-mentioned excellent properties can be obtained.

That is, when the aqueous pigment dispersion liquid, which is easily obtained as described above, is added to the oil phase, the pigment in the pigment dispersion liquid passes through the emulsifier existing in the oil phase before phase inversion. It is taken into the oil phase, and after phase inversion, it is included in the emulsion of the oil phase. As described above, as a means for obtaining colored resin fine particles having a higher color density, it is preferable that the oil phase further contains a coloring agent. That is, according to the method of the present invention, even if the pigment concentration in the oil phase is such that the polymerizable unsaturated monomer can be easily and uniformly dispersed, as described above, the pigment is uniformly dispersed. Since the dispersed pigment dispersion liquid uses the aqueous phase, it is possible to obtain colored resin fine particles of higher concentration by the phase inversion emulsification method.

According to the studies by the present inventors, an emulsion (emulsion) of a polymerizable unsaturated monomer in which a pigment is uniformly encapsulated through the emulsifier obtained as described above, is It was observed that the pigment tended to precipitate in the aqueous phase. Therefore, in the present invention, it is preferable to polymerize the polymerizable unsaturated monomer immediately after emulsification. The emulsion is heated by polymerization using a reactor equipped with a stirrer, a thermometer, a reflux condenser and a nitrogen gas inflow tube as a polymerization device,
Colored resin particles can be easily obtained.

The colored resin fine particles obtained as described above are characterized by having a very narrow particle size distribution and a uniform small particle size, and are also excellent in dispersion stability. The average particle diameter of the colored resin fine particles obtained after the polymerization is 500
It is preferably at most nm, more preferably at most 200 nm. That is, when the average particle diameter of the colored resin fine particles is large, sedimentation easily occurs due to long-term storage, and it becomes difficult to maintain dispersion stability. Further, in order to form colored resin fine particles having an average particle diameter within the above range, the average particle diameter of the polymerizable unsaturated monomer after phase inversion emulsification is 50
It is preferable to control so as to be 0 nm or less, and further preferable to control so as to be 200 nm or less.

The ink using the colored resin fine particles obtained as described above is excellent in dispersion stability and does not cause gelation or precipitation even after long-term storage. Further, since the resin ratio in the ink is high, when used for image formation, an image having water resistance and weather resistance, particularly scratch resistance is provided.

In the method for producing colored resin fine particles according to the embodiment of the present invention, a mixture containing at least a polymerizable unsaturated monomer, an emulsifier and a polymerization initiator is used as the oil phase. A colorant may be further added to the oil phase. Each constituent element will be described below.

(Polymerizable unsaturated monomer) As the polymerizable unsaturated monomer, vinyl aromatic hydrocarbon, (meth) acrylic acid ester, (meth) acrylamide, alkyl-substituted (meth) acrylamide, N- Examples thereof include substituted maleimide, maleic anhydride, (meth) acrylonitrile, methyl vinyl ketone, vinyl acetate, and vinylidene chloride.

Specific examples of vinyl aromatic hydrocarbons include:
For example, styrene, α-methylstyrene, o, m, p-
Examples thereof include, but are not limited to, chlorostyrene, p-ethylstyrene, and divinylbenzene alone or in combination of two or more. Specific examples of the (meth) acrylic acid ester-based monomer include, for example, methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, phenyl acrylate, methyl methacrylate. , Hexyl methacrylate, 2-ethylhexyl methacrylate, β-hydroxyacrylate, γ-
Examples thereof include, but are not limited to, propyl hydroxyacrylate, δ-hydroxybutyl acrylate, β-hydroxymethacrylic acid ethyl ester, ethylene glycol dimethacrylic acid ester, and tetraethylene glycol dimethacrylic acid ester.

These polymerizable unsaturated monomers can be used alone or in combination of two or more. Of course,
In order to improve the properties of the resulting colored resin fine particles depending on the application, a small amount of a water-soluble monomer may be added and polymerized.

Examples of the water-soluble monomer include those having an anionic group such as a sulfonic acid group, a phosphoric acid group and a carboxylic acid group. These acids are alkali metal salts such as sodium salts, ammonium salts, It may be in the form of amine salt or in the form of free acid. Suitable examples thereof are styrene sulfonic acid, sodium styrene sulfonate, 2-acrylamido-2-
Methyl propene sulfonic acid, 2-hydroxymethyl methacryloyl phosphate, 3-chloro-2-hydroxypropyl methacryloyl phosphate, acrylic acid, methacrylic acid, fumaric acid, crotonic acid, tetrahydroterephthalic acid, itaconic acid, maleic acid and the like.

(Emulsifier) Examples of emulsifiers used in the present invention include nonionic, anionic, or those containing both. However, in the phase inversion emulsification method which characterizes the present invention, a large amount of an emulsifier is often used, and therefore, there is a high possibility that the free emulsifier remains in the dispersion of the colored resin fine particles produced. Therefore, in order to reduce the free emulsifier to control the permeability of the recording liquid and further improve the water resistance of the recorded image, it is preferable to use the reactive emulsifier. The reactive emulsifier is an anionic and / or nonionic emulsifier having at least one unsaturated double bond in the molecule. Examples thereof include sulfosuccinic acid ester type and alkylphenol ether type.

Examples of the nonionic reactive emulsifier include those having a polyoxyethylene group in the molecule.
Specifically, "Adecaria Soap NE" (trade name, manufactured by Asahi Denka Co., Ltd.) containing polyoxyethylene allylglycidyl nonylphenyl ether as the main component, "Aqualon RN" containing polyoxyethylene nonylpropenyl ether as the main component (Trade name, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) and the like.

Examples of the anionic reactive emulsifier include sulfonic acid (salt) type, carboxylic acid (salt) type and phosphoric acid ester type. Specifically, "Adecaria Soap SE" (trade name, manufactured by Asahi Denka Co., Ltd.) containing sulfate ester salt of polyoxyethylene allyl glycidyl nonyl phenyl ether as a main component, and sulfate ester salt of polyoxyethylene nonyl propenyl ether are used. "Aqualon HS", "Aqualon BC" (trade name, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), etc. as the main components, and "Eleminol JS-2" and "Eleminol RS-3" having other structures.
0 "(product name Sanyo Chemical Industry Co., Ltd.)," Latemur "
(Manufactured by Kao Corporation), “New Frontier” (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), and the like, but are not limited thereto.

The reactive emulsifiers listed above may be used alone or in combination.
They can be used in combination of one or more kinds, or can be used in combination with a usual emulsifier. The amount of the emulsifier used is 5 to 5 based on the weight of all monomers.
It is preferably 50% by mass, more preferably 10 to 40% by mass. That is, when the amount of the emulsifier used is less than 5% by mass, phase inversion emulsification does not occur stably and phase separation may occur. On the other hand, when it exceeds 50% by mass, the water resistance of the image may be lowered when the image is formed by the ink to which the obtained colored fine particles are applied.

(Polymerization Initiator) As the polymerization initiator, a water-soluble or oil-soluble persulfate, a peroxide, an azo compound, a redox composition in which a reducing agent such as a peroxide and a sulfite is combined is used. Can be used. For example, ammonium persulfate,
Potassium persulfate, sodium persulfate, hydrogen peroxide, t-
Butyl hydroperoxide, t-butyl peroxyl benzoate, 2,2-azobisisobutyronitrile, 2,2-azobis (2-diaminopropane) hydrochloride, 2,2-azobis (2,4-dimethylvaleronitrile) ) And the like. Among them, the polymerization method is preferably carried out by suspension polymerization in which the migration of the monomer does not occur, and therefore a polymerization initiator soluble in the polymerizable unsaturated monomer is suitable.

The amount of such a polymerization initiator to be used is preferably 0.01 to 10% by mass, more preferably 0.05 to 5% by mass, based on the mass of all the monomers.

In producing the colored resin fine particles according to this embodiment, an oil phase comprising a mixture containing at least the polymerizable unsaturated monomer, the emulsifier and the polymerization initiator as described above is used. In addition to the above, a colorant as described below, and an additive such as an ultraviolet absorber, an antioxidant or a color improving agent may be added.

The present invention is characterized in that the aqueous phase is added to the oil phase constituted as described above to emulsify the components in the oil phase into the aqueous phase by phase inversion emulsification. As a water phase added to the oil phase, a pigment dispersion liquid in which a pigment is dispersed in water is used. The pigment used in this case will be described below.

(Pigment) The pigment to be contained in the water added in the phase inversion emulsification method is not particularly limited as long as it is a pigment that can be uniformly dispersed in water, but a self-dispersion pigment is particularly preferably used. The self-dispersion pigment preferably has ionicity, and examples thereof include those in which a hydrophilic group as shown below is bonded to the surface of the pigment. _{-COOM, -SO 3 M, -PO 3} HM, in -PO ₃ M ₂ above formula, M represents a hydrogen atom, an alkali metal, ammonium or organic ammonium. The hydrophilic group is not limited to the anionic type, and may be a pigment having a cationic group bonded.

The pigment that can be used in the present invention is not particularly limited, but for example, the pigments described below can be preferably used. First, the carbon black used in the black pigment ink is carbon black manufactured by a furnace method or a channel method, and has a primary particle size of 15 to 40.
mμm, specific surface area by BET method is 50 to 300 m ² /
g, a DBP oil absorption amount of 40 to 150 ml / 100 g, a volatile content of 0.5 to 10 mass% and a pH value of 2 to 9 are preferable.

Examples of such devices include No.
2300, No. 900, MCF88, No. 40, N
o. 52, MA7, MA8, No. 2200B (trade name or more, made by Mitsubishi Kasei), RAVEN 1255 (trade name, made in Colombia), REGAL 400R, REGAL 660R, MOGUL
L (trade name or more, manufactured by Kyabot), Color BlackF
W1, Color Black FW18, Color Black S17
0, Color Black S150, Printex 35, Printex
Commercially available products such as U (trade name or more, manufactured by Degussa) can be used. In addition, a new prototype may be used for the present invention.

Examples of pigments used in the yellow ink include CI Pigment Yellow 1 and CI Pigment Ye.
llow 2, CIPigment Yellow 3, CIPigment Ye
llow 13, CIPigment Yellow 16, CIPigment
Yellow 83 and the like can be mentioned.

Examples of pigments used as magenta ink include CI Pigment Red 5 and CI Pigment Red
7, CIPigment Red 12, CIPigment Red 4
8 (Ca), CI Pigment Red 48 (Mn), CI Pigmen
t Red 57 (Ca), CI Pigment Red 112, CI
Pigment Red 122 and the like.

Examples of pigments used as cyan ink include CI Pigment Blue 1 and CI Pigment Blue.
2, CIPigment Blue 3, CIPigment Blue 1
5: 3, CIPigment Blue 16, CIPigment Blue
22, CIVat Blue 4, CIVat Blue 6 and the like. Further, with respect to the coloring materials of any of the above colors, those newly manufactured for the present invention can be used.

In the present invention, in order to produce colored resin particles having a higher pigment concentration, a colorant is further mixed with the polymerizable unsaturated monomer, the emulsifier and the polymerization initiator described above. The oil phase of the composition which was stirred by
It is preferable to add a water phase composed of water containing a pigment to this and perform phase inversion emulsification. As the colorant used in this case, a colorant which can be dissolved or dispersed in an unsaturated monomer is selected, and examples thereof include dyes, pigments, and processed pigments obtained by imparting dispersibility to pigments. The processed pigment referred to here is a self-dispersion pigment in which at least one functional group is bonded to the surface of the pigment directly or through another atomic group, or a pigment coated with a pigment dispersant or a resin. It is a generic term for those that are expected to have additional functions added to the normal pigment manufacturing process. As the pigment, those listed above can be used.

Since the pigment and the processed pigment have excellent weather resistance,
It is particularly preferably used as a colorant to be contained in the oil phase. As the processed pigment that can be used in the present invention, a pigment having dispersibility in the unsaturated monomer used is selected, and for example, a surface treatment for improving dispersibility in the unsaturated monomer is performed. Those used are preferably used. In particular, it is preferable to use a pigment whose surface is previously coated with a water-insoluble resin which has an adsorptivity for the pigment and is compatible with the unsaturated monomer. Specifically, it is called a color chip (trade name: Taihei Chemical Co., Taisei Chemical Co., etc.) obtained by kneading a pigment and a resin under heating with two rolls, or Microlith (trade name: Ciba Specialty Chemicals). Commercially available processed pigments can be used. Further, a pigment obtained by any known method such as a simple coacervation method in which a pigment is dispersed in a resin solution and a poor solvent is added thereto to deposit the resin on the surface of the pigment can be used.

The water-insoluble resin for coating the pigment is freely selected from the adsorptivity to the pigment used and the solubility to the polymerizable unsaturated monomer used, but in particular vinyl chloride resin, Vinyl-based resins such as vinyl acetate resin, vinyl chloride-vinyl acetate copolymer resin, polyvinyl acetal resin, and cellulose-based resins and acrylic-based resins are preferable,
Among them, vinyl chloride-vinyl acetate copolymer resin is most suitable for finely stabilizing the pigment in the polymerizable unsaturated monomer. If desired, two or more water-insoluble resins may be used in combination.

Next, the step of polymerizing the polymerizable unsaturated monomer constituting the method for producing colored resin fine particles according to the embodiment of the present invention will be described. In the polymerization step, for example, an emulsion polymerization method using a pre-emulsification method and a suspension polymerization method can be used. The emulsion polymerization method and the suspension polymerization method are similar in that they use water as a medium, but the emulsion polymerization method uses a polymerization initiator insoluble in the monomer as the polymerization initiator, while the suspension polymerization method uses The difference is that a polymerization initiator that is soluble in the monomer is used. As a result, emulsion polymerization and suspension polymerization follow completely different polymerization mechanisms.

That is, in the suspension polymerization method, the polymerization proceeds in each monomer particle, while in the emulsion polymerization, the polymerization initiator is added to the micelle formed by the emulsifier in the system and a small amount of the monomer. Polymerization is initiated by diffusion, and a monomer is supplied from this to the monomer oil droplets to promote polymerization. In the present invention, uniform fine particles of a polymerizable unsaturated monomer containing a colorant such as a pigment are formed by pre-emulsification using a phase inversion emulsification method, and the particles are polymerized while maintaining their shapes. Thus, it is preferable to obtain colored resin fine particles. Therefore, in the present invention, it is preferable to perform the polymerization step by a suspension polymerization method which is a system in which the monomer does not move from the monomer particles.

In the conventional suspension polymerization method, a stabilizer such as polyvinyl alcohol was added in order to keep the monomer in a stable dispersed state, and the polymerization was carried out while vigorously stirring to disperse the monomer. Therefore, it has been generally known that polydisperse particles having a large particle size can be obtained as compared with emulsion polymerization. On the other hand, by using the method of the present invention, stable and uniform polymerizable unsaturated monomer particles having a small particle size can be formed by pre-emulsification using the phase inversion emulsification method. It is speculated that the suspension-polymerized particles also have a uniform and small particle size.

The average particle diameter of the colored resin fine particles obtained after polymerization is preferably 500 nm or less, more preferably 200 nm or less. As for the particle size distribution, 10% cumulative value is 25 nm or more, 90%
Those having a cumulative value of 1100 nm or less are preferably used. Here, the average particle diameter in the present invention is obtained by a cumulant analysis method in which the scattering intensity distribution due to the fine particles detected by the dynamic light scattering method is applied to a normal distribution to calculate the average particle diameter.

The particle size distribution is obtained from the frequency distribution when the scattering intensity detected by the same measurement method is analyzed by the Marquart analysis method of the histogram method, and is 10% when the scattering intensity is accumulated from the small particle size side. And the particle size distribution of fine particles is calculated from the particle size at 90%. These measurements were made by Otsuka Electronics Co., Ltd., electrophoretic light scattering photometer ELS-8000.
An apparatus capable of measuring the particle size distribution by a dynamic light scattering method such as the above can be preferably used, and the above-mentioned analysis processing can be processed by the attached software.

When the average particle size and the particle size distribution are within the above ranges, the dispersion stability of the colored resin fine particles is improved, and the colored resin fine particles do not easily agglomerate or settle even when stored for a long period under low temperature and high temperature environments. . Further, since the particles have a uniform particle size, when used as an ink for inkjet recording, clogging in the inkjet device is small, and the ejection property is good. In order to form colored resin fine particles having an average particle diameter within the above range, the average particle diameter of the monomer particles after phase inversion emulsification is preferably 500 nm or less, and more preferably 200 nm or less. preferable.

The colored resin fine particles produced according to the present invention as described above have good water resistance, and the ink image using this has good weather resistance, particularly good scratch resistance, and dispersion stability. Since it is also excellent, it can be suitably used as various recording inks. In particular, since it has good dispersibility in water, it is suitable as a constituent material of an aqueous inkjet recording ink.

It is to be noted that what is directly obtained by the above-mentioned method is that the colored resin fine particles are dispersed in an aqueous medium to be exact, and in the present invention, this is referred to as an aqueous dispersion of colored resin fine particles. When an ink is produced by using the colored resin fine particles according to the present invention, the colored resin fine particle water dispersion may be used as it is, depending on the composition of the ink to be obtained. Water is removed from the aqueous dispersion by a conventional method (for example, distillation, centrifugation, filtration, spray drying, etc.) and taken out as colored resin fine particles, and then dispersed again in an appropriate solvent such as an aqueous medium or an oily medium. It may be made into ink.

The ink using the colored resin fine particles of the present invention is constituted by the colored resin fine particles held in a dispersed state in an aqueous medium or an oily medium, and the aqueous medium contains at least water. Is preferred. In that case, the proportion of water in the total mass of the ink is, for example, 20 to 95% by mass, particularly 40 to 95% by mass, and further preferably 60 to 95% by mass.

In the aqueous medium, water may contain a water-soluble organic solvent as described below. Specific water-soluble organic solvents include, for example, methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol, and the like having 1 to 1 carbon atoms.
4, alkyl alcohols, amides such as dimethylformamide and dimethylacetamide, ketones such as acetone, ethers such as tetrahydrofuran and dioxane,
Polyalkylene glycols such as polyethylene glycol and polypropylene glycol, alkylene groups such as ethylene glycol, propylene glycol, butylene glycol, triethylene glycol, 1,2,6-hexanetriol, thiodiglycol, hexylene glycol and diethylene glycol Lower alkyl ethers of polyhydric alcohols such as alkylene glycols having 2 to 6 carbon atoms, glycerin, ethylene glycol monomethyl (or ethyl) ether, diethylene glycol monomethyl (or ethyl) ether, N-methyl-2-pyrrolidone , 1,3-dimethyl-2-imidazolidinone, sulfolane, dimethyl sulfoxide, 2
Examples include cyclic amide compounds such as -pyrrolidone and ε-caprolactam, and imide compounds such as succinimide.

The thus obtained water-based ink according to the present invention is suitably used in an ink jet recording method for recording an image by ejecting the ink from a recording head by thermal energy or mechanical energy and adhering it to a recording medium. . When the ink according to this aspect is particularly suitable for ink jet recording, the surface tension of the ink at 25 ° C. is 15 to 60 dyn / c.
m, further 20 to 50 dyn / cm, viscosity 15 cP
It is preferably below 10 cP, especially below 5 cP. The pH range is preferably 3 to 11, and more preferably 3.5 to 10.

Further, the ink using the colored resin fine particles according to the present invention may be constituted by maintaining the colored resin fine particles in a dispersed state in an oily medium. Alcohols (for example, alcohols such as ethanol, n-propanol, isopropanol, n-butanol, amyl alcohol, benzyl alcohol, cyclohexanol and the like, monoalkyl ethers of glycols such as ethylene glycol monomethyl ether and diethylene glycol monoethyl ether, and ethylene. It is preferable to use glycol monoacetates such as glycol monoacetate and propylene glycol monoacetate, and glycols such as ethylene glycol and diethylene glycol. Ink, for example, it is preferable to use the continuous type ink jet.

In the ink according to the present embodiment described above, in addition to the colored resin fine particles obtained as described above,
It may be configured by adding various additives such as a surfactant, a pH adjuster, and an antifungal agent. The recording medium used in the recording method using the ink according to the present aspect is not particularly limited, and for example, it is specially adjusted for plain paper such as copy paper and bond paper, or for inkjet recording. Examples include coated paper, glossy paper and OHP film.

The ink according to the present invention is particularly suitable for use in an ink jet recording system in which droplets are ejected by the action of thermal energy for recording, but it is also used for other ink jet recording methods and general writing instruments. It goes without saying that you can do it.

A recording apparatus suitable for recording using the ink of the present invention is an apparatus for applying thermal energy corresponding to a recording signal to the ink in the chamber of the recording head and generating a droplet by the energy. To be An example of the structure of the recording head, which is the main part, is shown in FIGS. 1, 2 and 3. The head 13 is made of glass, ceramics, a plastic plate, or the like having a groove 14 through which ink passes, and a heating head 15 having a heating resistor used for heat-sensitive recording (a head is shown in the drawing, but is not limited to this. It is not a thing) and is obtained by adhering. The heat generating head 15 has a good heat dissipation property such as a protective film 16 made of silicon oxide, aluminum electrodes 17-1 and 17-2, a heat generating resistor layer 18 made of nichrome, a heat storage layer 19 and alumina. It consists of a substrate 20.

The ink 21 is a discharge orifice (fine hole).
22 is filled, and the meniscus 23 is generated by the pressure P.
Is formed. FIG. 4 shows an example of an ink jet recording apparatus incorporating the head as described above. In FIG. 4, 61 is a blade as a wiping member,
One end thereof is held by the blade holding member to become a fixed end, which is in the form of a cantilever. Blade 61
Is arranged at a position adjacent to the recording area of the recording head, and in the case of the example shown in FIG. 4, is held in a protruding form in the movement path of the recording head. Reference numeral 62 denotes a cap, which is disposed at a home position adjacent to the blade 61, and has a configuration in which it moves in a direction perpendicular to the moving direction of the recording head and comes into contact with the ejection surface to perform capping. Furthermore,
Reference numeral 63 denotes an ink absorber provided adjacent to the blade 61, and like the blade 61, is held in a form protruding in the moving path of the recording head.

The blade 61, the cap 62, and the absorber 63 constitute an ejection recovery unit 64, and the ejection recovery unit 64 removes water, dust, and dust from the ink ejection port surface by the blade 61 and the absorber 63. Done. Reference numeral 65 denotes a recording head having ejection energy generating means for ejecting ink to a recording material facing the ejection port surface where the ejection ports are arranged to perform recording, and 66 denotes a recording head 65 in which the recording head 65 is mounted. It is a carriage for moving the. The carriage 66 slidably engages with the guide shaft 67, and a part of the carriage 66 is connected to a belt 69 driven by a motor 68 (not shown). As a result, the carriage 66 can move along the guide shaft 67, and the recording head 65 can move the recording area and its adjacent area.

Reference numeral 51 is a paper feed section for inserting a recording material, and 52 is a paper feed roller driven by a motor (not shown). With these configurations, the recording material is fed to a position facing the ejection opening surface of the recording head, and as recording progresses, the recording material is ejected to the ejection unit provided with the ejection roller 53. In the above configuration, when the recording head 65 returns to the home position after recording is completed, the cap 62 of the head recovery unit 64 is retracted from the movement path of the recording head 65, but the blade 61 is projected in the movement path. As a result, the ejection port surface of the recording head 65 is wiped.
When the cap 62 comes into contact with the ejection surface of the recording head 65 to perform capping, the cap 62 moves so as to project into the moving path of the recording head.

When the recording head 65 moves from the home position to the recording start position, the cap 62 and the blade 61 are in the same position as the above-mentioned position during wiping. As a result, even during this movement, the ejection port surface of the recording head 65 is wiped. The above-mentioned movement of the recording head to the home position is performed not only at the end of recording and at the time of ejection recovery, but also at the home position adjacent to the recording area at a predetermined interval while the recording head moves in the recording area for recording. Then, with this movement, the wiping is performed.

FIG. 5 is a cross-sectional view showing an example of an ink cartridge 45 in which the head is provided with an ink supply member, for example, an ink storage portion which stores ink supplied via a tube. Here, reference numeral 40 is an ink containing portion containing the supply ink, for example, an ink bag, and a rubber stopper 42 is provided at the tip thereof. By inserting a needle (not shown) into this stopper 42, the ink in the ink bag 40 can be supplied to the head. Reference numeral 44 is an ink absorber that receives waste ink.

The ink jet recording apparatus used in the present invention is not limited to the one in which the head and the ink cartridge are separated as described above, and one in which they are integrated as shown in FIG. 6 is also preferable. Used. In FIG. 6, reference numeral 70 denotes a recording unit, in which an ink containing portion containing ink, for example, an ink absorber is contained, and the ink in the ink absorber has a head portion having a plurality of orifices. The ink is ejected from 71 as an ink droplet. Reference numeral 72 denotes an atmosphere communication port for communicating the inside of the recording unit with the atmosphere. The recording unit 70 is used in place of the recording head 65 shown in FIG. 4, and is detachable from the carriage 66.

[0069]

EXAMPLES Next, the present invention will be specifically described with reference to Examples and Comparative Examples. The present invention is not limited to these. In the text, “part” and “%” are based on mass unless otherwise specified.

[Examples 1 to 3 and Comparative Example 1 Preparation and Evaluation Results of Colored Resin Fine Particle Aqueous Dispersion] (Preparation of Colored Resin Fine Particle Aqueous Dispersion) <Example 1: Preparation of Colored Resin Fine Particle Aqueous Dispersion A> Dissolve 4 parts of reactive emulsifier "Aqualon BC-20" (trade name, manufactured by Daiichi Pharmaceutical Co., Ltd.) in a mixed solution of 4 parts of styrene which is a polymerizable unsaturated monomer and 6 parts of 2-ethylhexyl acrylate. Further, 2,2- as a polymerization initiator was added to this solution.
0.14 parts of azobisisobutyronitrile was added and stirred to obtain a polymerizable unsaturated monomer mixture liquid containing the above components. On the other hand, 5 parts of a self-dispersion pigment (trade name of "CAB-O-JET200", a self-dispersion carbon black manufactured by Cabot Corporation), 3 parts of a 5% sodium hydroxide aqueous solution, and 12 parts of water.
In addition to the parts, the self-dispersion pigment was stirred with a high-speed shearing stirrer until it was dispersed in the state of primary particles to prepare an aqueous pigment dispersion liquid to be added during phase inversion emulsification.

Next, the polymerizable unsaturated monomer mixture solution obtained above was heated to a liquid temperature of 40 ° C. and stirred with a homogenizer at an addition rate of 0.2 part per minute to obtain the above. Pigment dispersion was added. When 20 parts of the pigment dispersion is added, the phase inversion point from the oil phase to the water phase is reached, but in order to obtain an emulsion having a uniform small particle size with a very narrow particle size distribution, at least a phase inversion point is used with a homogenizer. At the point of time, the mixture was stirred so that a sufficient shearing force was applied.

Next, 66 parts of water was added for dilution to obtain about 100 parts of an emulsion containing the pigment in the emulsion. Next, this emulsion was transferred to a reactor equipped with a stirrer, a thermometer, a reflux condenser and a nitrogen gas inflow tube, and polymerization was carried out under the following conditions. That is, while the liquid temperature was raised to 75 ° C., it was kept under a nitrogen stream, and after the temperature was raised, the inflow of nitrogen gas was stopped and the polymerization was carried out for 24 hours to obtain a colored resin fine particle water dispersion A.

<Example 2: Preparation of colored resin fine particle water dispersion B> 4 parts of a reactive emulsifier "Aqualon BC-20" (trade name, manufactured by Daiichi Pharmaceutical Co., Ltd.) was added with a polymerizable unsaturated monomer. It was dissolved in a mixed solution of 4 parts of methyl methacrylate and 6 parts of 2-ethylhexyl acrylate, and 0.1% of 2,2-azobisisobutyronitrile was added to this solution as a polymerization initiator.
4 parts were added and stirred to obtain a polymerizable unsaturated monomer mixture liquid containing the above components. On the other hand, a self-dispersion pigment (Cabot's self-dispersion carbon black CAB-O-JET20
0) 5 parts of 5% aqueous sodium hydroxide solution of 3 parts was added to 16 parts of water, and the mixture was stirred with a high-speed shearing stirrer until the self-dispersion pigment was dispersed in the form of primary particles. A pigment dispersion liquid of was prepared.

Next, the polymerizable unsaturated monomer mixture liquid obtained above was heated to a liquid temperature of 40 ° C. and stirred at the homogenizer to obtain the above at an addition rate of 0.2 parts per minute. The pigment dispersion was added. Although the phase inversion point from the oil phase to the aqueous phase is reached when 24 parts of the pigment dispersion is added, in order to obtain an emulsion having a uniform small particle size with a very narrow particle size distribution, at least a phase inversion point of a homogenizer is used. At this point, stirring was performed so that sufficient shearing force was applied.

Next, 61 parts of water was added for dilution to obtain about 100 parts of an emulsion containing the pigment in the emulsion. Next, this emulsion was transferred to a reactor equipped with a stirrer, a thermometer, a reflux condenser and a nitrogen gas inflow tube, and polymerization was carried out under the following conditions. That is, while the liquid temperature was raised to 75 ° C., it was kept under a nitrogen stream, and after the temperature was raised, the inflow of nitrogen gas was stopped and the polymerization was carried out for 24 hours to obtain a colored resin fine particle water dispersion B.

<Example 3: Preparation of aqueous dispersion C of fine colored resin particles> 4 parts of a reactive emulsifier "Aqualon HS-20" (trade name, manufactured by Daiichi Pharmaceutical Co., Ltd.) was added with a polymerizable unsaturated monomer. 4 parts of styrene and 2-ethylhexyl acrylate 6
Part of the mixture solution, 0.14 parts of 2,2-azobisisobutyronitrile as a polymerization initiator is added to the solution, and carbon black and a vinyl chloride / vinyl acetate copolymer are further added. Processed pigment "MICROLITH Black C
-K "(Product name: Pigment concentration 50%: Ciba Special
5 parts of Chemicals Co., Ltd. was added and stirred to obtain a polymerizable unsaturated monomer mixture liquid containing the above components.

On the other hand, a self-dispersion type pigment (a self-dispersion type carbon black "CAB-O-JET20" manufactured by Cabot Co., Ltd.
"0" brand name) 5 parts, 5 parts of 5% sodium hydroxide aqueous solution are added to 12 parts of water, and the mixture is stirred with a high-speed shearing stirrer until the self-dispersion pigment is dispersed in the state of primary particles. An aqueous pigment dispersion liquid to be added was prepared.

Next, the polymerizable unsaturated monomer mixture solution obtained above was heated to a liquid temperature of 40 ° C. and stirred with a homogenizer at an addition rate of 0.2 parts per minute to obtain the above-mentioned mixture. Pigment dispersion was added. When 20 parts of the pigment dispersion is added, the phase inversion point from the oil phase to the water phase is reached, but in order to obtain a uniform small particle size emulsion having a very narrow particle size distribution, at least a phase inversion point of a homogenizer is used. At this point, stirring was performed so that sufficient shearing force was applied.

Next, 61 parts of water was added for dilution to obtain about 100 parts of an emulsion containing the pigment in the emulsion. Next, this emulsion was transferred to a reactor equipped with a stirrer, a thermometer, a reflux condenser and a nitrogen gas inflow tube, and polymerization was carried out under the following conditions. That is, while the liquid temperature was raised to 75 ° C., it was kept under a nitrogen stream, and after the temperature was raised, the inflow of nitrogen gas was stopped and the polymerization was carried out for 24 hours to obtain a colored resin fine particle water dispersion C.

Comparative Example 1: Preparation of colored resin fine particle water dispersion D> A polymer dispersant "Disperbyk 161" (in a mixture of 4 parts of styrene and 6 parts of 2-ethylhexyl acrylate as a polymerizable unsaturated monomer) 1 part of the product name BICCHEM Japan Co., Ltd. (in terms of solid content) was dissolved,
As a coloring agent, 5 parts of REGAL 400R (trade name, manufactured by Cabot Corporation) and 10 parts of glass beads having a diameter of 0.5 mm are added, and the mixture is dispersed in a sand mill for 16 hours. After removing the glass beads, 0.14 parts of 2,2-azobisisobutyronitrile as a polymerization initiator was mixed to obtain a colorant solution.

As an emulsifier, a reactive emulsifier "Aqualon H"
S-20 "(trade name, manufactured by Daiichi Pharmaceutical Co., Ltd.)
The above colorant solution is added to 4 parts of the solution and stirred with a homomixer to obtain an emulsion. The obtained emulsion is placed in a polymerization device (a polymerization device equipped with a stirrer, a reflux condenser and a nitrogen gas inflow pipe), heated to 75 ° C. under a nitrogen stream and polymerized for 24 hours to disperse the colored resin fine particles in water. Body D is obtained.

(Evaluation Results of Colored Resin Fine Particle Water Dispersion) Each of the colored resin fine particle water dispersions obtained above was evaluated according to the following evaluation methods and criteria for the following evaluation items. The evaluation results are shown in Table 1 below.

Particle size The average particle size of the colored resin fine particle water dispersions A to D obtained above was measured by a dynamic light scattering method using "ELS-8000" (trade name, manufactured by Otsuka Electronics Co., Ltd.). It was measured at. Moreover, the average particle diameter was evaluated as a cumulant average value.

Storage stability Each of the colored resin fine particle water dispersions A to D obtained above is respectively
The container was sealed in a Teflon (registered trademark) container and stored at 60 ° C. for 2 months, and the presence or absence of gelation and sediment was visually evaluated. The evaluation results are classified as follows. A: Almost no gelation or sedimentation. ◯: A slight gelation or sediment was observed, but there was no problem in implementation. X: Gelation and sediment were severe.

[0085]

[Examples 4 to 6 and Comparative Example 2 Ink Preparation and Evaluation Results] (Preparation of Ink) Ink Preparation Ink of Examples 4 to 6 was prepared using the colored resin fine particle aqueous dispersions A to C. . To 5 parts of glycerin, 2 parts of ethylene glycol, 2 parts of trimethylolpropane, 1 part of acetylenol EH, 90 parts of the colored resin fine particle water dispersions A to C are respectively added.
And added with stirring. This was filtered to obtain the inks of Examples 4-6. An ink of Comparative Example 2 was prepared in the same manner as in Examples 4 to 6 except that the aqueous dispersion D of colored resin particles was used.

(Evaluation Result of Ink) Each of the inks obtained above was evaluated for the following evaluation items by the following evaluation methods and criteria. The evaluation results are shown in Table 2 below.

Storage Stability Each ink was sealed in a Teflon container and stored at 60 ° C. for 2 months, and the presence or absence of gelation or sediment was visually evaluated. The evaluation results are classified as follows. A: Almost no gelation or sedimentation. ◯: A slight gelation or sediment was observed, but there was no problem in implementation. X: Gelation and sediment were severe.

The four types of inks with improved ejection stability were filled in the ink tank of the BJ cartridge BC-21 mounted on the color BJ printer (trade name: BJC-420J; manufactured by Canon Inc.). Set the cartridge to BJC-420J, BJC-420J plain paper, 360 x 360
Printing was performed on recording paper (BJ-electrophotographic co-paper Canon PB paper; manufactured by Canon Inc.) in dpi and HQ modes. A 1-dot vertical line was printed on the recording paper at the beginning of use of the BC-21 cartridge. Further, the text was printed until the BC-21 cartridge was used up, and a 1-dot vertical line was printed on another recording paper using the cartridge just before use.

These recording papers were visually observed from a distance of 25 cm, and the print result by the cartridge at the beginning of use and the print result by the cartridge at the end of the use were evaluated according to the following criteria. A: There is no difference between the two. ◯: Although a dot landing deviation was recognized in a part of the vertical line printed by the cartridge just before the end of use, it can be recognized as a straight line. X: The dot landing deviation was clearly recognized on the vertical line printed by the cartridge just before the end of use, and the vertical line was misaligned.

[0091]

[0092]

As described above, according to the present invention, a coloring resin useful as a coloring material of an ink which gives an image having water resistance and weather resistance, particularly scratch resistance, and is excellent in dispersion stability. Microparticles can be provided. Particularly, according to the present invention, it is possible to provide colored resin fine particles useful as a coloring material for ink jet recording ink. Further, according to the present invention, there is provided a method for producing colored resin particles or an aqueous dispersion of colored resin particles, in which colored resin particles having a high color density and a uniform small particle diameter can be easily obtained.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a head portion of an inkjet recording apparatus.

FIG. 2 is a cross-sectional view of a head portion of an inkjet recording device.

FIG. 3 is an external perspective view of a head portion of the inkjet recording apparatus.

FIG. 4 is a perspective view showing an example of an inkjet recording apparatus.

FIG. 5 is a vertical sectional view of an ink cartridge.

FIG. 6 is a perspective view of a recording unit.

[Explanation of symbols]

13: Head 14: groove 15: Heating head 16: Protective film 17-1, 17-2: Aluminum electrodes 18: Heating resistor layer 19: Heat storage layer 20: substrate 21: Ink 22: Discharge orifice (fine hole) 23: Meniscus 25: Recording material 28: Heating head 40: Ink bag 42: Stopper 44: Ink absorber 45: Ink cartridge 51: Paper feed section 52: Paper feed roller 53: Paper ejection roller 61: Wiping member 62: Cap 63: Ink absorber 64: Head recovery unit 65: recording head 66: Carriage 67: Guide shaft 68: Motor 69: Drive belt 70: Recording unit 71: Head part 72: Air communication port

Continued front page    (72) Inventor Hideyuki Takai             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation (72) Inventor Masaaki Hiro             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation (72) Inventor Makiko Endo             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation F-term (reference) 2C056 EA13 FA03 FB02 FC02                 2H086 BA53 BA54 BA55 BA59                 4J011 JA06 JB09 JB11 JB26                 4J039 AB02 AD02 AD04 AD05 AD08                       AD09 AD10 AD11 AD12 AD14                       AD23 BD02 BE01 CA06 EA34                       EA36 EA38 EA41 EA44 EA46                       GA24

Claims (20)

[Claims] 1. (i) At least a polymerizable unsaturated monomer,
Colored resin fine particles having a step of adding an aqueous medium to an oil phase containing an emulsifier and a polymerization initiator, and emulsifying the above components in the aqueous medium; and (ii) polymerizing the polymerizable unsaturated monomer. The method for producing
In, using water in which the pigment is dispersed as an aqueous medium,
A method for producing colored resin fine particles, which comprises emulsifying by a phase inversion emulsification method. 2. The method for producing colored resin fine particles according to claim 1, further comprising a colorant in the oil phase in the step (i). 3. The method for producing colored resin fine particles according to claim 2, wherein the colorant is a pigment. 4. The method for producing colored resin fine particles according to claim 2, wherein the colorant is a pigment previously coated with a water-insoluble resin. 5. The method for producing colored colored resin fine particles according to claim 4, wherein the water-insoluble resin is at least one resin selected from a vinyl resin, a cellulose resin and an acrylic resin. 6. The method for producing colored resin fine particles according to claim 4, wherein the water-insoluble resin is a vinyl chloride-vinyl acetate copolymer. 7. The method for producing colored resin fine particles according to claim 1, wherein the emulsifier is a reactive emulsifier. 8. The polymerization initiator is an oil-soluble polymerization initiator soluble in a polymerizable unsaturated monomer, and the step (i
The method for producing colored resin fine particles according to claim 1, wherein the suspension polymerization method is used in i). 9. (i) A step of adding an aqueous medium to an oil phase containing a polymerizable unsaturated monomer, an emulsifier and a polymerization initiator, and emulsifying the above components in the aqueous medium; and (ii) the above polymerization. A process for producing a colored resin fine particle water dispersion, which comprises a step of polymerizing a polyunsaturated monomer, wherein in the step (i), water in which a pigment is dispersed is used as an aqueous medium, and a phase inversion emulsification method is used. A method for producing an aqueous dispersion of colored resin fine particles, which comprises emulsifying. 10. (i) An aqueous medium comprising water in which a pigment is dispersed in an oil phase containing a polymerizable unsaturated monomer, an emulsifier and a polymerization initiator is added, and the above components are phase-inverted into the aqueous medium. Emulsifying by an emulsification method; (ii) polymerizing the polymerizable unsaturated monomer; and (iii) removing water from the colored resin fine particle water dispersion obtained by the steps (i) and (ii). A method for producing colored resin fine particles, which comprises: 11. Colored resin fine particles produced by the method according to claim 10. 12. An ink comprising a colored resin fine particle produced by the method according to any one of claims 1 to 8 and a liquid medium. 13. The ink according to claim 12, wherein the liquid medium is an aqueous medium. 14. The ink according to claim 12, wherein the liquid medium is an oil medium. 15. A water-based ink comprising an aqueous dispersion of colored resin fine particles produced by the method according to claim 9. 16. The ink according to claim 12, wherein the ink is for inkjet. 17. A recording unit, comprising: an ink containing portion containing the ink according to claim 16; and a head portion for ejecting the ink. 18. An ink cartridge comprising an ink containing portion containing the ink according to any one of claims 12 to 16. 19. An ink jet recording apparatus comprising: an ink containing portion containing the ink according to claim 16; and a recording head for ejecting the ink. 20. An ink jet recording method comprising a step of ejecting the ink according to claim 16 using an ink jet method.