JP2011022275A - Method for manufacturing toner for infrared fixing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance the image quality of a fixed image by toner for infrared fixing. <P>SOLUTION: A method for manufacturing the toner for infrared fixing having a colored resin particle 11 containing at least a colorant 13 and a resin coating layer 14 containing at least an infrared absorbent 16 which coats the surface of the colored resin particle 11 includes: an aqueous dispersion solution preparation step of preparing an aqueous dispersion solution containing colored resin particles 11, resin fine particles 15 and infrared-absorbing fine particles; and a filming step of forming the above resin coating layer 14 by heating the aqueous dispersion solution or adding a flocculant to the aqueous dispersion solution, whereby the resin fine particles 15 and the infrared absorbent fine particles are flocculated on the surfaces of the colored resin particles 11 and coat the surfaces. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an infrared fixing toner used in an image forming apparatus using an infrared fixing method.

  In an electrophotographic image forming apparatus, for example, an electrostatic latent image is formed on an image carrier such as a photoconductor, developed with a developer containing toner to form a toner image, and the toner image is formed on a recording sheet such as paper. An image is formed by transferring and fixing (recording medium, recording material).

  As a fixing method for fixing toner on a recording sheet, for example, a hot-pressure fixing method in which a heated roller member is pressed against a recording sheet onto which a toner image has been transferred to melt and fix the toner, or the toner image is transferred. There is known an infrared fixing method in which a recording sheet is irradiated with infrared rays to melt and fix the toner.

  Here, in the hot-pressure fixing method, since the heated roller member comes into contact with the recording sheet, there is a problem that image smearing due to hot offset, paper jam, and the like occur.

  On the other hand, in the infrared fixing method, it is not necessary to bring a heated roller member or the like into contact with the recording sheet, and thus the above problem does not occur. However, in the infrared fixing method, there is a new problem that the color toner has a low infrared absorptance and thus has low energy efficiency.

  On the other hand, the applicant of the present application has applied for a toner in which an infrared absorber is contained in the shell portion of the toner surface layer portion (Patent Document 1). According to this, since the infrared ray absorber on the toner surface layer portion effectively absorbs infrared rays, energy efficiency can be improved even when used in the infrared fixing method.

JP 2007-298582 (published November 15, 2007)

  However, in a toner in which an infrared absorbent is contained in the shell portion, if the infrared absorbent is not uniformly dispersed and is present on the toner surface in a partially aggregated state, the toner is not effective when irradiated with infrared rays. It has been found that there is a problem in that heat is generated uniformly and voids are generated.

  This is presumably because the resin agglomeration (void) occurs on a part of the toner surface due to excessive heat generation in the aggregated portion of the infrared absorbent due to the irradiation of infrared rays.

  In particular, in the case of a color toner, if the infrared absorbent is present on the toner surface in an aggregated state, the transparency of the infrared absorbent is reduced due to the aggregation of the infrared absorbent, so that the saturation and brightness of the obtained fixed image are reduced. I also found that there is.

  The present invention has been made in view of the above-described conventional problems, and its purpose is to suppress the generation of voids, and for infrared fixing capable of exhibiting excellent saturation and lightness even in a color fixed image. Toner and a method for producing the same.

  In order to solve the above problems, the method for producing an infrared fixing toner according to the present invention includes a colored resin particle containing at least a colorant, and a resin coating containing at least an infrared absorber covering the surface of the colored resin particle. A method for producing an infrared fixing toner having a layer, wherein an aqueous dispersion solution preparing step for preparing an aqueous dispersion solution containing colored resin particles, resin fine particles and infrared absorbent fine particles, and heating the aqueous dispersion solution or A film forming step of forming the resin coating layer by adding a flocculant to the aqueous dispersion solution to agglomerate the resin fine particles and the infrared absorbent fine particles on the surface of the colored resin particles to coat the surface. It is characterized by including.

  According to this, colored resin particles, resin fine particles, and infrared absorbent fine particles are dispersed in an aqueous solvent to form an aqueous dispersion solution, and the aqueous dispersion solution is heated or a flocculant is added to the aqueous dispersion solution. The resin fine particles and the infrared absorbent fine particles are aggregated and coated on the surface of the colored resin particles. By uniformly dispersing the resin fine particles and the infrared absorber in the aqueous dispersion solution, the infrared absorber can be uniformly dispersed in the resin coating layer. As a result, it is possible to obtain a toner in which the infrared absorbent fine particles are uniformly dispersed on the surface of the colored resin particles as the toner base particles. In an image using such a toner, no voids are generated, and the color of the image is reduced. An image with excellent brightness and brightness can be obtained.

  In the method for producing an infrared fixing toner according to the present invention, the infrared absorber is preferably a cyanine compound.

  Since the cyanine compound has a maximum absorption peak and a high extinction coefficient (10 × 5 or more) in the wavelength range of 780 nm or more and 1000 nm or less, the cyanine compound is an excellent infrared absorber with high laser light absorption efficiency. Therefore, by using a cyanine compound as an infrared absorber, it is possible to obtain a higher effect of ensuring sufficient fixability and preventing image blanking due to voids in an infrared fixing system.

  In the method for producing an infrared fixing toner according to the present invention, the number average particle diameter of the colored resin particles is preferably 2 μm or more and 10 μm or less.

  According to this, by reducing the diameter of the colored resin particles within the above range, it is possible to obtain a high image density even if the amount of the infrared fixing toner adhering is small, thereby reducing the consumption of the infrared fixing toner. can do. In addition, the infrared fixing toner can stably form a high-definition image over a long period of time.

  In the method for producing an infrared fixing toner according to the present invention, the number average particle diameter of the resin fine particles is preferably 0.05 μm or more and 0.5 μm or less.

  According to this, by reducing the resin fine particles forming the resin coating layer within the above range, it is possible to easily achieve both blocking resistance and fixability of the infrared fixing toner. If it is less than 0.05 μm, it is difficult to uniformly cover the toner surface, for example, the thickness of the coating layer to be formed becomes thin, and the blocking resistance tends to decrease. On the other hand, if it exceeds 0.5 μm, the coating layer becomes thick and the low-temperature fixability tends to be lowered.

  In the method for producing an infrared fixing toner according to the present invention, the resin fine particles include a resin having a carboxylate in a side chain, and are aggregated on the surface of the colored resin particles in the film forming step. It is preferable to include a process of converting the carboxylate of the resin contained in the resin fine particles coated with a carboxylic acid.

  According to this, by using resin fine particles containing a resin having a carboxylate in the side chain, self-dispersibility can be obtained, and an aqueous dispersion can be formed without using a dispersant such as a surfactant. Further, by converting the carboxylate to carboxylic acid after coating, the hydrophobicity of the surface layer of the infrared fixing toner can be increased, and the moisture resistance of the infrared fixing toner can be increased.

  In the method for producing an infrared fixing toner according to the present invention, the treatment for converting the carboxylate into a carboxylic acid is preferably performed by adding an acid.

  As described above, the method for producing an infrared fixing toner according to the present invention includes an aqueous dispersion solution preparation step for preparing an aqueous dispersion solution containing colored resin particles, resin fine particles, and infrared absorbent fine particles, and the aqueous dispersion solution described above. By heating or adding an aggregating agent to the aqueous dispersion, the resin fine particles and the infrared absorbent fine particles are aggregated on the surface of the colored resin particles to coat the surface, thereby forming the resin coating layer. A film forming step.

  Therefore, it is possible to produce an infrared fixing toner that suppresses the generation of voids when irradiated with infrared rays and exhibits excellent saturation and lightness even in a color fixed image.

FIG. 6 is a process diagram illustrating an example of a procedure of a toner manufacturing method according to the present invention. FIG. 2 is a cross-sectional view showing an infrared fixing toner manufactured by the toner manufacturing method shown in FIG. 1. FIG. 3 is a cross-sectional view illustrating an example of a configuration of an image forming apparatus that can use the infrared fixing toner illustrated in FIG. 2. FIG. 4 is a cross-sectional view illustrating a configuration of a developing device provided in the image forming apparatus illustrated in FIG. 3. 3A is a front view of the fixing device included in the image forming apparatus shown in FIG. 3, FIG. 4B is a top view of the fixing device viewed from the I direction shown in FIG. 3A, and FIG. FIG. 2 is a front view of the fixing device as seen from the II direction shown in FIG.

  Hereinafter, it will be as follows if one Embodiment of this invention is described based on FIGS. In the present embodiment, a case where a color toner is manufactured by the infrared fixing toner manufacturing method 1 according to the present invention will be described.

  FIG. 1 is a process diagram showing an example of the procedure of a toner manufacturing method 1 according to the present invention. As shown in FIG. 1, the toner production method 1 includes an aqueous dispersion solution preparation step S1, an aqueous dispersion solution mixing step S2, a colored resin particle forming step S3, a coating layer forming step (film forming step) S4, It includes a filtration washing step S5, a drying step S6, and an external addition step S7.

  2 is a cross-sectional view showing the toner 10 manufactured by the toner manufacturing method 1 shown in FIG. As shown in FIG. 2, the toner 10 has a surface of the colored resin particles 11 containing the binder resin 12 and the colorant 13 by a coating layer (resin coating layer) 14 containing the resin fine particles 15 and the infrared absorber 16. It is covered. Further, in the coating layer 14, the infrared absorbent 16 is uniformly dispersed in the resin fine particles 15. Hereinafter, each step will be described.

(1: Aqueous dispersion solution preparation step S1)
In the aqueous dispersion solution preparation step S1, an aqueous dispersion solution is prepared in which each material for forming the colored resin particles 11 as the core particles is made into particles and dispersed in an aqueous dispersion medium. As shown in FIG. 2, the colored resin particles 11 are particles including a binder resin 12 and a colorant 13. Moreover, you may contain additives (illustration omitted), such as a charge control agent or a mold release agent, as needed.

  The aqueous dispersion medium used for each aqueous dispersion solution is a dispersion medium composed of a liquid containing water as a main component, and may contain a water-soluble organic solvent or the like.

  As the water-soluble organic solvent, butanol, isopropanol, ethanol, butyl cellosolve, ethyl cellosolve, dioxane, tetrahydrofuran, acetone, methyl ethyl ketone and the like can be used. In addition, the water-soluble organic solvent is not essential for producing an aqueous dispersion solution in which the colored resin particles 11 are dispersed, and can be appropriately used as necessary. Hereinafter, a method for preparing each aqueous dispersion solution will be described.

(1-1: Aqueous dispersion solution of binder resin)
The aqueous dispersion solution of the binder resin 12 can be prepared, for example, by melt-emulsifying the binder resin 12 into fine resin particles with a stirrer such as a homogenizer and then dispersing it in an aqueous dispersion medium.

  The number average particle diameter of the binder resin 12 dispersed in the aqueous dispersion solution is preferably 0.01 μm or more and 0.3 μm or less. If it is less than 0.01 μm, the hydrophilicity is too high, so that sufficient moisture resistance cannot be obtained for the obtained toner. On the other hand, if it exceeds 0.3 μm, it is difficult to uniformly disperse the colorant 13 in the colored resin particles 11, and the color reproducibility of the toner is lowered. In particular, when a water-soluble organic solvent is used as the aqueous dispersion medium, it takes time to remove the water-soluble organic solvent when the particle diameter of the binder resin 12 increases. For this reason, from the viewpoint of production efficiency, the number dispersed particle size of the binder resin 12 is preferably 0.3 μm or less.

  Further, the dispersed particle size of the binder resin 12 depends on the content of hydrophilic groups in the binder resin 12, and the dispersed particle size decreases as the content increases. Further, the dispersed particle size of the binder resin 12 also depends on the molecular weight. The smaller the molecular weight, the smaller the dispersed particle size. Therefore, the dispersed particle size of the binder resin 12 in the aqueous dispersion medium can be controlled by changing the content or molecular weight of the hydrophilic group.

  As the binder resin 12, for example, a polyester resin, a crystalline polyester resin, an epoxy, and a self-dispersing resin having a hydrophilic group such as a sulfonic acid, a sulfonate, a carboxylic acid, or a carboxylate in a side chain is used. can do.

  It does not specifically limit as a polyester resin, A well-known thing can be used, For example, the polycondensation product of polybasic acids and polyhydric alcohols can be used.

  Polybasic acids are polybasic acids and derivatives of polybasic acids, such as acid anhydrides or esterified products of polybasic acids.

  Polyhydric alcohols are compounds containing two or more hydroxyl groups, and include both alcohols and phenols.

  As the crystalline polyester resin, those commonly used in this field can be used, and those obtained by condensation polymerization of alcohols and carboxylic acids are particularly preferred.

  As the alcohols, aliphatic diols are preferable. The carbon number of the aliphatic diol is preferably 2 or more and 6 or less, more preferably 4 or more and 6 or less. Specific examples of the aliphatic diol include, for example, ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, neo Pentyl glycol, 1,4-butenediol, and the like can be used. Among these, α, ω-linear alkanediol is preferable, and 1,4-butanediol and 1,6-hexanediol are more preferable.

  The content of the aliphatic diol is not particularly limited and can be appropriately selected from a wide range, but is preferably 80 mol% or more and 100 mol% or less, more preferably 85 mol% or more of all alcohols, It is 100 mol% or less, Most preferably, it is 90 mol% or more and 100 mol% or less.

  Examples of alcohols other than aliphatic diols include polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene (2.2) -2,2-bis (4 -Hydroxyphenyl) propane and other bisphenol A alkylene (2 to 3 carbon atoms) oxide (average added mole number 1 to 10) adducts such as divalent aromatic alcohols, glycerin, pentaerythritol, trimethylolpropane Trihydric or higher alcohols such as can be used. Alcohol can be used individually by 1 type, and may use 2 or more types together.

  As the carboxylic acids, aliphatic dicarboxylic acid compounds are preferable. The number of carbon atoms of the aliphatic dicarboxylic acid compound is preferably 2 or more and 8 or less, more preferably 4 or more and 6 or less. Specific examples of the aliphatic dicarboxylic acid compound include, for example, oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, adipic acid and other aliphatic dicarboxylic acids and aliphatic dicarboxylic acid anhydrides. Products, aliphatic dicarboxylic acid C1-4 alkyl esters, and the like. Of these, aliphatic dicarboxylic acids are preferred. The content of the aliphatic dicarboxylic acid compound is not particularly limited and can be appropriately selected from a wide range, but is preferably 80 mol% or more and 100 mol% or less, more preferably 85 mol% of all carboxylic acids. Above, it is 100 mol% or less, Especially preferably, it is 90 mol% or more and 100 mol% or less.

  Examples of carboxylic acids other than aliphatic dicarboxylic acid compounds include, for example, aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, and terephthalic acid, linear dicarboxylic acids such as sebacic acid, azelaic acid, n-dodecyl succinic acid, and n-dodecenyl succinic acid. Acids, cycloaliphatic dicarboxylic acids such as cyclohexanedicarboxylic acid, trivalent or higher polyvalent carboxylic acids such as trimellitic acid and pyromellitic acid, anhydrides thereof, C1-3 alkyl esters, and the like can be used. Carboxylic acids can be used individually by 1 type, and may use 2 or more types together.

  The polycondensation of alcohols and carboxylic acids can be performed according to a known method, for example, in an inert gas atmosphere, in the presence of an esterification catalyst or a polymerization inhibitor, if necessary, at 120 ° C. The reaction may be performed at 230 ° C. or lower.

  “Crystallinity” means that in the resin, the ratio of the softening temperature to the maximum peak temperature of the heat of fusion (softening temperature / maximum peak temperature of the heat of fusion) is 0.9 or more and 1.1 or less, Preferably, it means 0.98 or more and 1.05 or less.

  In addition, when a resin having a sulfonate salt in the side chain is used as the binder resin 12, when aggregating using a divalent or higher aggregating agent such as magnesium sulfate, via sulfate ions and magnesium ions, An ionic crosslinking structure can be taken. Thereby, since the same effect as the high molecular weight of the resin can be obtained, the hot offset resistance can be improved. For example, in the melt emulsification method, if a resin having a large molecular weight is dispersed from the beginning, the time required for the dispersion becomes long, so that there is a demerit that productivity is lowered. On the other hand, according to the method having an ionic cross-linked structure, a resin having a low molecular weight can be used at the time of emulsification and dispersion, so that both the productivity and the hot offset resistance of the resulting toner can be improved.

  The resin having a sulfonate in the side chain is not particularly limited, but a self-dispersing polyester resin having a sulfonate in the side chain is preferable from the viewpoint of low-temperature fixability.

  Self-dispersing polyester resin having sulfonate in the side chain is a polycondensation of polyhydric alcohols with polycarboxylic acid or polyhydric alcohols, with monomers having sulfonates in the side chain or polyhydric alcohol monomers. Can be obtained. Polycondensation of polyhydric alcohols and carboxylic acids can be performed according to a known method. For example, in an inert gas atmosphere, the reaction may be performed at 120 ° C. or higher and 230 ° C. or lower in the presence of an esterification catalyst or a polymerization inhibitor as necessary.

  Examples of polyhydric alcohols that can be used include aliphatic polyhydric alcohols, alicyclic polyhydric alcohols, and aromatic polyhydric alcohols.

  Examples of aliphatic polyhydric alcohols include ethylene glycol, propylene glycol, 1,3-propanediol, 2,3-butanediol, 1,4-butanediol, 1,5-pentanediol, and 1,6-hexane. Diols, neopentyl glycol, diethylene glycol, dipropylene glycol, 2,2,4-trimethyl-1,3-pentanediol, aliphatic diols such as polyethylene glycol, polypropylene glycol and polytetramethylene glycol, trimethylol Triols such as ethane, trimethylolpropane, glycerin and pentaerythritol, tetraols, and the like can be used.

  Examples of the alicyclic polyhydric alcohols include 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, spiroglycol, hydrogenated bisphenol A, ethylene oxide adduct and propylene oxide adduct of hydrogenated bisphenol A, Tricyclodecanediol, tricyclodecane dimethanol and the like can be used.

  Examples of aromatic polyhydric alcohols include paraxylene glycol, metaxylene glycol, orthoxylene glycol, 1,4-phenylene glycol, ethylene oxide adduct of 1,4-phenylene glycol, bisphenol A, and bisphenol A. Ethylene oxide adducts and propylene oxide adducts can be used.

  Moreover, the alcohol component may contain monoalcohols in polyhydric alcohols. As monoalcohols, aliphatic alcohols, aromatic alcohols and alicyclic alcohols can be used.

  Examples of the polyvalent carboxylic acid include terephthalic acid, isophthalic acid, orthophthalic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, anthracene dipropionic acid, anthracene dicarboxylic acid, diphenic acid, sulfoterephthalic acid, Aromatic dicarboxylic acids such as 5-sulfoisophthalic acid, 4-sulfophthalic acid, 4-sulfonaphthalene-2,7 dicarboxylic acid, 5 (4-sulfophenoxy) isophthalic acid, sulfoterephthalic acid, metal salts and ammonium salts thereof; Aliphatic unsaturated polycarboxylic acids such as succinic acid, adipic acid, azelaic acid, sebacic acid and dodecanedicarboxylic acid, fumaric acid, maleic acid, itaconic acid, mesaconic acid and citraconic acid, phenylene diacrylic Aromatic unsaturation such as acid Valence carboxylic acid, hexahydrophthalic acid, can be used alicyclic dicarboxylic acids such as tetrahydrophthalic acid, trimellitic acid, trimesic acid, and the like trivalent or higher polyvalent carboxylic acids such as pyromellitic acid.

  Moreover, what contains monocarboxylic acids in polyhydric carboxylic acids as an acid component may be sufficient. As monocarboxylic acids, aromatic monocarboxylic acids are preferable. Examples of aromatic monocarboxylic acids include benzoic acid, chlorobenzoic acid, bromobenzoic acid, parahydroxybenzoic acid, naphthalenecarboxylic acid, anthracenecarboxylic acid, 4-methylbenzoic acid, 3-methylbenzoic acid, salicylic acid, and thiosalicylic acid. , Phenylacetic acid, lower alkyl esters thereof, sulfoammonium monoammonium salt, sulfobenzoic acid monosodium salt, cyclohexylaminocarbonylbenzoic acid, n-dodecylaminocarbonylbenzoic acid, tertiarybutylbenzoic acid and tertiarybutylnaphthalenecarboxylic acid Etc. can be used.

  As the monomer having a sulfonate in the side chain, polyvalent carboxylic acids or monocarboxylic acids having an alkali metal sulfonate, ammonium sulfonate or the like in the side chain can be used. For example, 5-sodium sulfoxy There is isophthalic acid. The hydrophilic monomer may be added and polymerized at the same time as other monomers from the start of polymerization, but may be added during the polymerization.

  The ionic group of the toner has a function of imparting water dispersibility to the polyester resin, but when the counter cation is a polyvalent ion, the water dispersibility cannot be sufficiently exhibited. Accordingly, the counter cation of these ionic group-containing monomers in polymerizing the polyester resin is preferably a monovalent cation.

  Moreover, as a metal ion more than bivalence, magnesium chloride other than magnesium sulfate, aluminum sulfate, etc. can be used, for example.

  In consideration of the moisture resistance of the finally obtained toner 10 and the water dispersibility in the production process, the ionic equivalent of the polyester resin is preferably in the range of 10 meq / kg or more and 1000 meq / kg or less, and 20 meq. More preferably, it is in the range of not less than / kg and not more than 100 meq / kg.

  For example, an aqueous dispersion of a self-dispersing polyester resin having a sulfonate salt in a side chain is preheated to, for example, a polyester resin having a sulfonate salt in a side chain and a water-soluble organic solvent at 50 ° C. or more and 200 ° C. or less, respectively However, there is a method of preparing these by mixing them and then adding water. As another method, water is added to a mixed solution of a polyester resin having a sulfonate salt in a side chain and a water-soluble organic solvent, and then heated to 40 ° C. or higher and 120 ° C. or lower and stirred. It may be prepared.

(1-2: Aqueous dispersion of colorant)
As the aqueous dispersion of the colorant 13, a solution obtained by emulsifying and dispersing the colorant 13 together with a surfactant with a stirrer and having a number average particle size of 0.3 μm or less can be used.

  The content of the colorant 13 can be selected from a wide range according to the required toner characteristics, but is preferably 0.1% by weight or more and 20% by weight with respect to 100% by weight of the binder resin 12. Or less, more preferably 0.1 wt% or more and 15 wt% or less. When the content of the colorant 13 is less than 0.1% by weight, it becomes difficult to obtain a sufficient image density. On the other hand, if it exceeds 20% by weight, it becomes difficult to ensure the dispersibility of the colorant 13 in the formed image.

  As the colorant, organic dyes, organic pigments, inorganic dyes, inorganic pigments and the like commonly used in the field of electrophotography can be used, and water-soluble dyes that do not aggregate even when a flocculant is added. Except for this, there is no particular limitation.

  Examples of the colorant 13 for yellow toner include C.I. I. Pigment Yellow 1, 3, 4, 5, 6, 12, 13, 14, 15, 16, 17, 18, 24, 55, 65, 73, 74, 81, 83, 87, 93, 94, 95, 97, 98, 100, 101, 104, 108, 109, 110, 113, 116, 117, 120, 123, 128, 129, 133, 138, 139, 147, 151, 153, 154, 155, 156, 168, 169, 170, 171, 172, 173, 180, 185, etc. can be used. I. Pigment Yellow 17 (disazo), 74 (monoazo), 155 (condensed azo), and 180 (benzimidazolone) are preferable.

  Examples of the magenta toner colorant 13 include C.I. I. Pigment Red 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 14, 15, 17, 18, 22, 23, 31, 37, 38, 41, 42, 48: 1, 48: 2, 48: 3, 48: 4, 49: 1, 49: 2, 50: 1, 52: 1, 52: 2, 53: 1, 53: 3, 54, 57: 1, 58: 4, 60: 1, 63: 1, 63: 2, 64: 1, 65, 66, 67, 68, 81, 83, 88, 90, 90: 1, 112, 114, 115, 122, 123, 133, 144, 146, 147, 149, 150, 151, 166, 168, 170, 171, 172, 174, 175, 176, 177, 178, 179, 185, 187, 188, 189, 190, 193, 194, 202, 208, 209, 214, 216, 220, 221, 224, 242, 243, 243: 1, 245, 246, 247, etc. can be used. I. Pigment Red 48: 1 (barium red), 48: 2 (calcium red), 48: 3 (strontium red), 48: 4 (manganese red), 53: 1 (lake red), 57: 1 (brilliant carmine), 122 (quinacridone magenta) and 209 (dichloroquinacridone red) are preferred.

  As the colorant 13 of the cyan toner, phthalocyanine C.I. I. Pigment Blue 1, 2, 15: 1, 15: 2, 15: 3, 15: 4, 15: 6, 15, 16, 17: 1, 27, 28, 29, 56, 60, 63, etc. In particular, C.I. I. Pigment Blue 15: 3 (phthalocyanine blue G), 15 (phthalocyanine blue R), 16 (metal-free phthalocyanine blue), and 60 (indanthrone blue) are preferable.

  As the black toner colorant 13, carbon black produced by various methods can be used.

  Further, in addition to the colorant 13, a self-dispersing pigment that can be dispersed without adding a surfactant can be used. Examples of self-dispersing pigments include sulfonic acid groups, carboxyl groups and polymers on the pigment surface as disclosed in JP-T-10-510661, JP-T 2000-513396, and JP-T 2003-519709. Are preferably introduced directly onto the pigment surface. Moreover, what coated the pigment surface with a sulfonic acid group, a carboxyl group, a polymer, etc. by the phase inversion emulsification method etc. can be used.

  The self-dispersing pigment has a hydrophilic functional group on the surface of the pigment, and the hydrophilic functional group is preferably an ionic group and / or an ionizable group. Examples of the hydrophilic functional group include a carboxylic acid group, a group having a carboxylate, a sulfonic acid group, a group having a sulfonate, a sulfophenyl group, a group having a benzenesulfonate, a p-sulfophenyl group, p -Use benzenesulfonate group, carboxyphenyl group, benzenecarboxylate group, sulfoamide group, amidosulfate group, quaternary ammonium salt group, derivatives thereof, and mixtures thereof can do. Self-dispersing pigments can be easily dispersed uniformly in water, and pigment aggregates are unlikely to be generated in the resulting toner, and an image with excellent color reproducibility can be obtained.

  The colorant 13 can be used alone or in combination of two or more. Furthermore, when using 2 or more types of coloring agents 13 together, the coloring agents 13 of the same color may be used together, or the coloring agents 13 of a plurality of colors may be used together.

(1-3: Aqueous dispersion of charge control agent)
A charge control agent can be added to the colored resin particles 11 of the present embodiment as necessary. By adding a charge control agent, the charging characteristics of the toner 10 can be controlled. As the aqueous dispersion solution of the charge control agent, it is possible to use a dispersion obtained by stirring the charge control agent together with the dispersant and the surfactant with a stirring device.

  As the aqueous dispersion of the charge control agent, an aqueous dispersion in which the charge control agent is dispersed so that the number average particle diameter of the charge control agent is 0.3 μm or less can be used. In order to obtain a toner having excellent reproducibility, it is preferable to use a charge control agent dispersed in a dispersed particle size of 0.3 μm or less.

  The amount of the charge control agent added is preferably 0.1 parts by weight or more and 10 parts by weight or less, more preferably 0.5 parts by weight with respect to 100 parts by weight of the binder resin 12. The amount is 5 parts by weight or less.

  As a charge control agent for controlling positive charge, an organic compound having a basic nitrogen atom, such as a basic dye, a quaternary ammonium salt, an aminopyrine, a pyrimidine compound, a polynuclear polyamino compound, an aminosilane, or nigrosine base is used. be able to.

  Use oil-soluble dyes such as oil black and spiron black, metal-containing azo dyes, metal salts of naphthenic acid, metal salts of alkyl salicylic acid, fatty acid soaps, resin acid soaps, etc. as charge control agents for controlling negative charges. Can do.

(1-4: Aqueous dispersion solution of release agent)
A release agent can be added to the colored resin particles 11 of the present embodiment as necessary. You may add a mold release agent simultaneously with the charge control agent mentioned above.

  As the aqueous dispersion of the release agent, a dispersion obtained by stirring the release agent together with the dispersant and the surfactant with a stirrer can be used.

  Moreover, as the aqueous dispersion solution of the release agent, an aqueous dispersion solution in which the release agent is dispersed so that the number average particle diameter of the release agent is 0.3 μm or less can be used, but more transparent. In order to obtain a toner having excellent properties and color reproducibility, it is preferable to use a release agent having a dispersed particle diameter of 0.3 μm or less.

  As the mold release agent, known ones can be used. For example, petroleum wax such as paraffin wax and microcrystalline wax, carnauba wax, rice wax, candelilla wax, plant wax such as wood wax, beeswax, whale Animal waxes such as wax, mineral waxes such as montan wax and ozokerite, oil-based synthetic waxes such as fatty acid amides and phenol fatty acid esters, hydrocarbon-based synthetics such as low molecular weight polypropylene wax, low molecular weight polyethylene wax, and Fischer-Tropsch wax Wax, alcohol-based synthetic wax, ester-based synthetic wax and the like can be used. These release agents may be used alone or in combination of two or more.

  When preparing an aqueous dispersion solution of the binder resin 12, an aqueous dispersion solution of the colorant 13, an aqueous dispersion solution of the charge control agent, and an aqueous dispersion solution of the release agent, the dispersion particle diameter is controlled. Therefore, a surfactant may be used as long as the moisture resistance is not affected.

  The surfactant that can be used may be any of a nonionic surfactant, an anionic surfactant, a cationic surfactant, and an amphoteric surfactant. However, when a polyester resin particle having a sulfonate salt in the side chain is agglomerated, when a divalent or higher aggregating agent such as magnesium sulfate or aluminum sulfate is used, a colorant is used in that uniform agglomerated particles are formed. It is preferable that the surfactant used for the mold release agent is substantially free of a cationic surfactant.

  Examples of the nonionic surfactant include polyoxyalkylene alkyl ethers such as polyoxyethylene lauryl ether and polyoxyethylene stearyl ether; polyoxyalkylene alkyl phenol ethers such as polyoxyethylene octylphenol ether and polyoxyethylene nonylphenol ether. Sorbitan fatty acid esters such as sorbitan monolaurate, sorbitan monostearate, sorbitan trioleate; polyoxyalkylene sorbitan fatty acid esters such as polyoxyethylene sorbitan monolaurate; polyoxyethylene monolaurate, polyoxyethylene monostea Polyoxyalkylene fatty acid esters such as oleates; oleic acid monoglyceride, stearic acid monoglyceride Glycerol fatty acid esters such as chloride; polyoxyethylene-polypropylene block copolymers may be used.

  Examples of the anionic surfactant include fatty acid salts such as sodium stearate, sodium oleate and sodium laurate; alkylaryl sulfonates such as sodium dodecylbenzenesulfonate; alkyl sulfate esters such as sodium lauryl sulfate; Alkyl sulfosuccinic acid ester salts such as sodium octyl sulfosuccinate, sodium dioctyl sulfosuccinate, sodium polyoxyethylene lauryl sulfosuccinate and derivatives thereof; polyoxyalkylene alkyl ether sulfates such as sodium polyoxyethylene lauryl ether sulfate; polyoxyethylene Use polyoxyalkylene alkyl aryl ether sulfates such as nonylphenol ether sulfate. It can be.

  Examples of the cationic surfactant include alkylamine salts such as laurylamine acetate; quaternary ammonium salts such as lauryltrimethylammonium chloride and alkylbenzyldimethylammonium chloride; polyoxyethylalkylamine and the like.

  As the amphoteric surfactant, for example, alkylbetaines such as laurylbetaine can be used. Moreover, in amphoteric surfactant, what substituted a part of hydrogen of the alkyl group with the fluorine can be used.

  In addition, in colored resin particle formation process S3 mentioned later, it has a metal ion more than bivalence from the aqueous dispersion mixed solution containing the aqueous dispersion solution of the binder resin 12 which consists of self-dispersing resin which has a sulfonate in a side chain. When the colored resin particles 11 are formed using an aggregating agent, it is desirable from the viewpoint of controlling the uniform particle diameter that the dispersant is substantially free of a cationic surfactant.

(2: Aqueous dispersion solution mixing step S2)
In the aqueous dispersion solution mixing step S2, the aqueous dispersion solution of the binder resin 12 prepared in the aqueous dispersion solution preparation step S1, the aqueous dispersion solution of the colorant 13, the aqueous dispersion solution of the charge control agent, and the aqueous release agent. An aqueous dispersion mixed solution is prepared by mixing with the dispersion solution and stirring.

(3: Colored resin particle forming step S3)
In the colored resin particle forming step S3, an aggregating agent is added to the aqueous dispersion mixed solution mixed in the aqueous dispersed solution mixing step S2 to form an aggregate of the colored resin particles 11. Further, the aqueous dispersion mixed solution is heated to the glass transition point of the binder resin 12 to prepare an aqueous dispersion solution of the colored resin particles 11 that are well-shaped aggregated particles.

  As the aggregating agent, known ones such as an electrolyte or an organic substance having ions can be used, but a polyvalent ion compound capable of forming an ionic crosslinking structure between polymer molecules is preferable because it has an effect of increasing the molecular weight. As the polyvalent ion compound capable of taking an ionic cross-linked structure, polyvalent metal salts such as magnesium sulfate and aluminum sulfate are particularly preferable because they are easily dissolved in water and easily washed with pure water.

  The number average particle diameter of the colored resin particles 11 is preferably in the range of 2 μm or more and 10 μm or less. If it is less than 2 μm, it is difficult to uniformly charge the obtained toner, and image defects are likely to occur. On the other hand, if the particle diameter exceeds 10 μm, the particle diameter of the obtained toner becomes large and satisfactory image quality is difficult to obtain. In particular, in order to achieve the purpose of improving the image quality, those having a number average particle diameter of 2 μm or more and 7 μm or less are more preferable.

  Thus, in the present embodiment, the colored resin particles 11 are formed through the aqueous dispersion solution preparation step S1, the aqueous dispersion solution mixing step S2, and the colored resin particle forming step S3. Specifically, the binder resin 12 is melted and emulsified into fine resin particles with a stirrer such as a homogenizer and dispersed in an aqueous dispersion medium, and then an aqueous dispersion of a colorant, a charge control agent, and a release agent is mixed. The colored resin particles 11 were formed by adding an aggregating agent and aggregating.

  In this embodiment, the colored resin particles 11 are formed by aggregating the binder resin 12 and the colorant 13 dispersed in the aqueous dispersion mixed solution. However, the present invention is not limited to this, and the monomer is not limited to this. The colored resin particles 11 may be formed by suspension polymerization of an aqueous suspension of the binder resin 12 and the colorant 13 included. Further, for example, the colored resin particles 11 are formed by a chemical method such as a melt emulsification method, a polymerization method such as an emulsion polymerization agglomeration method, a pulverization method, and the like, and this is dispersed in an aqueous dispersion medium. May be created. When a dry method such as a pulverization method is used, the charge control agent, the release agent and the like are dispersed in the binder resin 12 using a melt kneader in advance.

  However, from the viewpoint of particle size controllability and production efficiency for small particle size toners and freedom of selection of resin material, the particles are aggregated from an aqueous dispersion liquid mixture composed of a binder resin 12 and a colorant 13 as in the present embodiment. Thus, a method of obtaining an aqueous dispersion solution of the colored resin particles 11 is preferable.

(4: Coating layer forming step S4)
In the coating layer forming step S4, the aqueous dispersion solution of the colored resin particles 11 prepared in the colored resin particle forming step S3, the aqueous dispersion solution of the resin fine particles 15, and the aqueous dispersion solution of the infrared absorber 16 are mixed to be colored. A resin layer 15 and an infrared absorbent 16 are agglomerated and coated on the surface of the resin particle 11 to form a coating layer 14.

  First, the preparation method of the aqueous dispersion solution of the resin fine particles 15 and the aqueous dispersion medium of the infrared absorber 16 used in this step will be described. In addition, the thing similar to what was used by aqueous dispersion solution preparation process S1 mentioned above can be used for the aqueous dispersion medium used for preparation of each aqueous dispersion solution of the resin fine particle 15 and the infrared absorber 16.

(4-1: Aqueous dispersion of resin fine particles)
The aqueous dispersion solution of the resin fine particles 15 can be prepared, for example, by melting and emulsifying the resin fine particles 15 into fine resin particles with a stirring device such as a homogenizer and then dispersing the fine resin particles in an aqueous dispersion medium.

  The resin fine particles 15 are not particularly limited as long as they have an average particle diameter smaller than the number average particle diameter of the colored resin particles 11, but are preferably 0.05 μm or more and 0.5 μm or less. If the number average particle diameter of the resin fine particles 15 is less than 0.05 μm, it is difficult to uniformly cover the toner surface, for example, the thickness of the coating layer 14 to be formed becomes thin, and the blocking resistance tends to decrease. Become. On the other hand, when the thickness exceeds 0.5 μm, the thickness of the coating layer 14 increases, and the low-temperature fixability tends to be lowered.

  The glass transition point of the resin fine particles 15 can usually be 45 ° C. or higher and 75 ° C. or lower. For example, storage stability (aggregation resistance under a high temperature environment) and low temperature fixability can be achieved by using a colored resin particle 11 that is 2 ° C. or more and 10 ° C. or less higher than the glass transition point. .

The softening temperature of the resin fine particles 15 is preferably a softening temperature that can be easily melted by infrared irradiation during image fixing, for example, 60 ° C. or higher and 150 ° C. or lower. Here, the softening temperature of this embodiment uses a flow tester CFT-500 type (manufactured by Shimadzu Corporation), the sample amount is 1 g, the die size is 1.0 × 1.0, and the extrusion load 2 is 0 kgf / cm ^2. The temperature at the time of 1/2 stroke when measuring the temperature rising rate at 6 ° C., the starting temperature at 60 ° C., and the preheating time at 300 seconds was used.

  As the material of the resin fine particles 15, the same material as that of the binder resin 12 described above can be used. However, it is preferable that the resin fine particles 15 do not contain a crosslinking component.

  The aqueous dispersion solution of the resin fine particles 15 is prepared, for example, by dissolving a self-dispersing resin having a carboxylate in the side chain in a water-soluble organic solvent such as butanol, and then injecting it into water and performing phase inversion emulsification. can do. The self-dispersing resin can be obtained by, for example, polycondensation of a polyvalent carboxylic acid and a polyvalent alcohol, and then treating with an amine or an alkali metal hydroxide to remove carboxylic acid remaining unreacted in the resin. It can be obtained by a method of converting to a carboxylate. By imparting hydrophilicity by converting a carboxylic acid into a carboxylate, self-dispersibility in which the resin fine particles 15 themselves are dispersed in an aqueous dispersion medium can be imparted without adding a surfactant. Considering the point of imparting hydrophilicity, the cation of the carboxylate is preferably an alkali metal, and can be obtained by treatment with an alkali metal hydroxide such as sodium hydroxide.

  Since the carboxylate has high hydrophilicity, it can give the resin fine particles 15 self-dispersibility. Furthermore, after forming the aggregated coated particles, the aggregated coated particles are treated with an acid such as hydrochloric acid. By doing so, the carboxylate on the surface of the aggregated coated particles can be returned to the carboxylic acid. As a result, the hydrophobicity of the surface of the aggregated coated particles can be increased, so that the moisture resistance of the obtained toner 10 can be improved. As a specific treatment method, for example, an aqueous dispersion solution of aggregated particles is heated to a temperature of Tg or higher to form stronger aggregated particles, and then pH 2 or higher in a suspension in which the aggregated coated particles are dispersed, A method of adding an aqueous hydrochloric acid solution adjusted to pH 3 or lower is preferred.

  The particle size of the self-dispersing resin dispersed in the aqueous dispersion medium can be controlled by changing the molecular weight of the resin and the carboxylate content in the resin. If the molecular weight of the resin fine particles 15 is reduced, emulsification is facilitated and the dispersed particle size is reduced. If the amount of the carboxylate in the resin fine particles 15 is increased, emulsification is facilitated and the dispersed particle size is reduced. However, if the acid value is too large, the hygroscopicity is increased. As a result, the resulting toner has moisture resistance. That is, the acid value is preferably 5 mgKOH / g or more and 30 mgKOH / g or less in order to cause a decrease in charge amount and a decrease in transfer efficiency in a high humidity environment.

  As a method for increasing the carboxylic acid group contained in the polyester resin, there is a method using a trivalent or higher carboxylic acid monomer. If a trivalent or higher carboxylic acid monomer is added at the initial stage of the polymerization reaction, a cross-linked structure is imparted to the polyester resin and subsequent emulsification and dispersion becomes difficult. As a result, the high molecular weight due to the crosslinking reaction can be minimized and the acid value of the polyester resin can be increased.

  When trivalent or higher polyvalent carboxylic acids such as trimellitic acid, trimesic acid and pyromellitic acid are used together with the above polyvalent carboxylic acids, unreacted carboxylic acid groups are more likely to be contained. If it is introduced at the end of the reaction, it becomes easy to introduce a carboxylic acid group without causing a crosslinking reaction.

  In the process of forming the resin fine particles 15, in addition to the self-dispersing resin having a carboxylate in the side chain, a resin having no self-dispersing property can be simultaneously added. In that case, if the content of the self-dispersing resin having the carboxylate in the resin fine particles 15 in the side chain is 50% by weight or less, it becomes difficult to make a uniform aqueous dispersion solution. The resin content is preferably 50% by weight or more.

(4-2: Aqueous dispersion of infrared absorber)
The aqueous dispersion solution of the infrared absorbent 16 can be prepared, for example, by suspending and dispersing the fine particles of the infrared absorbent 16 in an aqueous dispersion medium.

The infrared absorber 16 preferably has an absorption maximum wavelength λmax in a wavelength range of 780 nm or more and 1000 nm or less. The absorption of visible light by the infrared absorbent 16 is preferably as small as possible in order to suppress the influence on the hue of the toner. Here, “infrared rays” refers to electromagnetic waves having a wavelength of 780 nm to 10 ⁶ nm (1 mm), and “visible rays” refers to electromagnetic waves having a wavelength of 380 nm to less than 780 nm.

  The content of the infrared absorber 16 in the toner 10 is preferably 0.01% by weight or more and 1% by weight or less. When the content of the infrared absorber is less than 0.01% by weight, the amount of heat generated during infrared irradiation is reduced as compared with the case where the content is 0.01% by weight or more. For this reason, the toner is not sufficiently melted, and the fixability may be lowered. On the other hand, when the content of the infrared absorber exceeds 1% by weight, the toner is more likely to be rapidly melted by infrared irradiation than when the content is 1% by weight or less. For this reason, voids are generated due to bumping, causing white spots in the image. In addition, the amount of visible light absorbed by the infrared absorbent 16 is increased, which may reduce the saturation of the image. Therefore, by setting the content of the infrared absorber 16 to not less than 0.01% by weight and not more than 1% by weight, the toner 10 can be sufficiently fixed, and white spots of images and deterioration of saturation can be prevented.

  The number average particle diameter of the infrared absorber 16 is preferably 0.1 μm or more and 0.5 μm or less. If the number average particle diameter of the infrared absorber 16 is less than 0.1 μm or more than 0.5 μm, it becomes difficult to fix the infrared absorbent 16 together with the resin fine particles 15 on the toner surface.

  A conventionally well-known thing can be used as the infrared absorber 16, and if it has absorption in an infrared region, it will not specifically limit. For example, the infrared absorber 16 composed of one or more compounds selected from a cyanine compound, carbon black, a diimonium compound, an aminium compound, a polymethine compound, a phthalocyanine compound, and the like can be used.

  Examples of the cyanine compound include KAYASORB CY-40MC and CYP-4646 (F) (trade name) manufactured by Nippon Kayaku Co., Ltd., NK-4680 (trade name) of Hayashibara Biochemical Laboratories, Ltd., Sumitomo Seika Co., Ltd. SD50-E05N (trade name) manufactured by Co., Ltd. can be used.

  As the diimonium compound, for example, CIR-1085 and CIR-1085F (all are trade names) manufactured by Nippon Carlit Co., Ltd. can be used.

  As the aminium compound, NIR-AM1 (trade name) manufactured by Nagase ChemteX Corporation can be used, for example.

  As the polymethine compound, for example, IRT (trade name) manufactured by Showa Denko KK can be used.

  As the phthalocyanine compound, for example, IR-10A, IR-12 (trade name) manufactured by Nippon Shokubai Co., Ltd. can be used.

  Among these compounds, the cyanine compound has a maximum absorption peak and a high extinction coefficient (10 × 5 or more) in a wavelength range of 780 nm or more and 1000 nm or less, and therefore has high laser light absorption efficiency. It is preferable to use it. By including a cyanine compound as the infrared absorber 16, in the infrared fixing system, it is possible to obtain a higher effect of ensuring sufficient fixability and preventing whiteout of the image due to voids.

  Next, a method for agglomerating and covering the surface of the colored resin particles 11 with the coating layer 14 will be described. The aqueous dispersion solution of the colored resin particles 11, the aqueous dispersion solution of the resin fine particles 15, and the aqueous dispersion solution of the infrared absorber 16 are mixed and stirred. Then, heating or aggregating agent is added in a state where the colored resin particles 11, the resin fine particles 15, and the infrared absorbent 16 are dispersed in the aqueous dispersion solution. Thereby, the fine particles of the resin fine particles 15 and the fine particles of the infrared absorbent 16 are aggregated in a state of being uniformly dispersed in the aqueous dispersion solution, and the surfaces of the colored resin particles 11 are coated to form aggregated coated particles.

  Here, when the aggregated coated particles are formed by heating, the aqueous dispersion mixed solution is heated to 70 ° C., for example. Moreover, when forming the aggregation covering particle | grains with a coagulant | flocculant, the thing similar to the coagulant | flocculant used by colored resin particle formation process S3 can be used.

  As described above, the resin particles 15 and the infrared absorber 16 are agglomerated and coated on the surfaces of the colored resin particles 11 in the aqueous dispersion medium, so that the infrared absorber 16 is uniformly dispersed among the resin particles 15. Agglomerated coated particles having a surface layer in a dry state can be formed.

  In addition, by heating or adding an aggregating agent while stirring the aqueous dispersion, the surface of the colored resin particles can be efficiently coated with a coating layer in which the infrared absorbent is uniformly dispersed.

  Next, the aqueous dispersion medium of the aggregated coated particles is heated to the glass transition point of the resin fine particles 15. Thus, the coating layer 14 is formed by fixing the fine particles of the resin fine particles 15 on the surface of the colored resin particles 11 in a state where the infrared absorbent 16 is uniformly dispersed, and the aggregated coated particles having a uniform shape are formed. Can do. Further, it is possible to obtain the toner 10 in which the coating layer 14 is difficult to peel off in a developing tank of an image forming apparatus described later.

  Finally, a precipitate of agglomerated coated particles can be obtained by applying a hydrophobic treatment by adding dilute hydrochloric acid.

  The coating layer 14 preferably has a thickness of 0.05 μm or more and 0.5 μm or less. If the film thickness is less than 0.05 μm, the storage stability cannot be sufficiently improved, while if it exceeds 0.5 μm, the low-temperature fixability deteriorates.

  The thickness of the coating layer 14 can be controlled by adjusting the particle diameters of the colored resin particles 11 and the resin fine particles 15 to be mixed and the mixing ratio of the colored resin particles 11 and the resin fine particles 15. The coating layer 14 is not limited to one layer, and two or more types of resin fine particles having different glass transition points or softening points can be coated.

  When a self-dispersing resin coating having a carboxylate in the side chain is used for the resin fine particles 15, the hydrophobicity of the toner 10 can be obtained by converting the carboxylate in the side chain of the resin fine particles 15 into a carboxylic acid. Moisture resistance). The method of converting the carboxylate in the side chain into a carboxylic acid can be performed by adding an acid during or after aggregation. As a specific treatment method, for example, an aqueous dispersion solution of aggregated coated particles is heated to a temperature equal to or higher than the glass transition temperature to form stronger aggregated coated particles, and then a suspension in which the aggregated coated particles are dispersed. In addition, there is a method of adding an aqueous hydrochloric acid solution adjusted to pH 2 or more and 3 or less.

(5: Filtration washing step S5)
In the filtration washing step S5, the aggregated coated particle precipitate formed in the coating layer forming step S4 is purified by filtration and then washed with pure water.

  The cleaning with pure water is performed to remove unnecessary components such as impurities that affect the chargeability of the toner 10. The washing method is not particularly limited, and may be performed in a batch manner or in a continuous manner.

  The toner 10 is preferably washed until the supernatant has a conductivity of 50 μS / cm or less, and the pure water used for the washing preferably has a conductivity of 20 μS / cm or less. Such pure water can be obtained by a known method. For example, an activated carbon method, an ion exchange method, a distillation method, a reverse osmosis method, or the like can be used. A plurality of methods may be combined. In the cleaning, the temperature of the pure water is preferably 10 ° C. or higher and 80 ° C. or lower.

(6: Drying step S6)
In the drying step S6, unnecessary components of the toner 10 are removed in the cleaning step S5, and then the toner 10 is dried under reduced pressure conditions. Thereby, the toner 10 shown in FIG. 2 can be obtained.

  As shown in FIG. 2, since the infrared absorbent 16 is uniformly dispersed in the coating layer 14 of the toner 10, unlike the conventional toner, the uneven heat generation of the toner due to the aggregation of the infrared absorbent 16 is prevented. can do. Thereby, according to the toner 10, generation of voids can be suppressed, and a fixed image exhibiting excellent saturation and lightness can be realized even with color toners.

  As described above, according to the toner manufacturing method 1 according to the present embodiment, the surface of the colored resin particles 11 is agglomerated and coated with the fine particles of the resin fine particles 15 and the fine particles of the infrared absorbent 16 in the aqueous dispersion medium. Thus, the coating layer 14 in which the infrared absorbent 16 is uniformly dispersed is formed. As a result, it is possible to manufacture the toner 10 that does not generate voids and has high image saturation and brightness during infrared fixing.

  When the coating layer 14 having a softening temperature higher than that of the colored resin particles 11 is formed, blocking of the toner 10 during storage and non-uniform charging performance due to shape deformation can be prevented. For this reason, the coating layer 14 is effective in improving the toner blocking resistance, durability, shape stability during storage, and the like.

  Further, when the coating layer 14 having a softening temperature lower than that of the colored resin particles 11 by about 10 ° C. or more and about 30 ° C. or less is formed, both low-temperature fixability and hot offset resistance can be achieved. That is, when the amount of infrared irradiation is not sufficient at the time of fixing, the low softening point coating layer 14 existing on the toner surface is melted, so that the adhesion between the toner 10 and the paper surface necessary for fixing the toner 10 is achieved. Can give power. On the other hand, when the amount of infrared irradiation is large at the time of fixing, the colored resin particles 11 having a high softening point present in the toner 10 can contribute to hot offset resistance.

(7: External addition step S7)
In the external addition step S7, an external additive is added as necessary to improve the fluidity of the produced toner 10. Therefore, in the external addition step S7, the toner 10 and the external additive are mixed using an air stirrer such as a Henschel mixer, and the externally added toner 10 is created. In addition, since the toners 10 obtained in the drying step S6 adhere to each other and form a gentle aggregation, it is desirable that the toners 10 be previously pulverized with a Henschel mixer or the like.

  The external additive is not particularly limited, and generally used silica, titanium oxide, aluminum oxide having a number average particle diameter of 0.007 μm or more and 0.02 μm or less, and a silane coupling agent or titanium coupling thereof. Inorganic fine particles that have been surface-treated with an agent and silicone oil can be used.

  Further, since the surface of the toner 10 obtained in the present embodiment is relatively smooth, the second outer surface having a number average particle diameter of 0.03 μm or more is provided for the purpose of improving transferability and cleaning properties and preventing aggregation. It is desirable to use an additive in combination. As the second external additive, for example, silica having a number average particle size of 0.03 μm or more, titanium oxide, aluminum oxide, and these were surface-treated with a silane coupling agent, a titanium coupling agent, and silicone oil. In addition to inorganic fine particles, fatty acid metal salts, zinc stearate, calcium stearate, lead stearate, zinc oxide powder, vinylidene fluoride fine particles, fluorine resin fine particles such as polytetrafluoroethylene fine particles, and the like can be used.

  The amount of the external additive to be added is desirably in the range of 0.3 to 3 parts by weight with respect to 100 parts by weight of the toner 10. If it is less than 0.3 part by weight, the effect of improving the fluidity cannot be obtained, and if it exceeds 3 parts by weight, the fixability is lowered.

  Further, abrasive fine particles may be added to the toner 10. Specifically, fine abrasive particles such as strontium titanate, cerium oxide, silicon carbide, and magnetite can be added. These abrasive fine particles may be treated with a coupling agent such as a silane coupling agent or a titanium coupling agent, silicone oil, or other organic compounds.

  As the number particle diameter of the abrasive fine particles, those having a particle size of 0.04 or more and 2 μm or less can be used. Further, when the amount of the abrasive fine particles added is too large, the surface of the electrostatic latent image carrier and the developer carrier surface wears quickly, so the amount added is 2 parts by weight or less with respect to 100 parts by weight of the toner 10. preferable.

  A known emulsifier or disperser can be used as the stirrer used in the infrared fixing toner manufacturing method 1 according to the present embodiment. Specifically, Ultra Turrax (trade name: manufactured by IKA Japan Co., Ltd.), Polytron homogenizer (trade name: manufactured by Kinematica Co., Ltd.) and TK Auto Homo Mixer (trade name: manufactured by Tokushu Kika Kogyo Co., Ltd.) Batch type emulsifier, Ebara Milder (trade name: manufactured by Ebara Manufacturing Co., Ltd.), TK Pipeline Homomixer (trade name: manufactured by Tokushu Kika Kogyo Co., Ltd.), TK Homomic Line Flow (trade name: Special Machine) Chemical Industry Co., Ltd.), Fillmix (trade name: Special Machine Chemical Industry Co., Ltd.), colloid mill (trade name: Shinko Pantech Co., Ltd.), Thrasher (trade name: Mitsui Miike Chemical Industries, Ltd.) ), Trigonal wet milling machine (trade name: manufactured by Mitsui Miike Chemical Co., Ltd.), Cavitron (trade name: manufactured by Eurotech Co., Ltd.) and Fine Flow Mill (trade name: Taiheiyo Kiko Co., Ltd.) ) Continuous emulsification machine such as, Claire mix: manufactured (trade name M Technique Co., Ltd.) and fill mix: the like can be used (trade name Kika Kogyo Co., Ltd.). The emulsifier and the disperser preferably have a heat retaining means.

  Next, an image forming apparatus that can use the toner 10 will be described. FIG. 3 is a cross-sectional view showing an example of the configuration of an image forming apparatus that can use the infrared fixing toner manufactured by the toner manufacturing method according to the present embodiment. The image forming apparatus 100 is a multifunction machine having both a copying function, a printer function, and a facsimile function, and forms a full-color or monochrome image on the recording sheet P in accordance with transmitted image information. That is, the image forming apparatus 100 has three types of print modes, ie, a copy mode (copy mode), a printer mode, and a FAX mode. Operation input from an operation unit (not shown), a personal computer, a portable terminal device, Each print mode is selected by a control unit (not shown) according to reception of a print job from an external device using an information recording storage medium or a memory device.

  As shown in FIG. 3, the image forming apparatus 100 includes a toner image forming unit 52, a transfer unit 53, a fixing device 54, a recording sheet supply unit 55, and a discharge unit 56. Each member constituting the toner image forming unit 52 and some of the members included in the transfer unit 53 include black (b), cyan (c), magenta (m), and yellow (y ), A total of four are provided, one for each color. Here, the members provided according to the colors are distinguished from each other by attaching an alphabet representing each color to the end of the reference symbol, and when referring collectively, only the reference symbol is used.

  The toner image forming unit 52 includes a photosensitive drum 61, a charging device 62, an exposure unit 63, a developing device 64, and a cleaning unit 65. The toner image forming means 52 forms an electrostatic latent image on the surface of the photosensitive drum 61 that has been uniformly charged by the charging device 62 by irradiating light corresponding to image information from the exposure unit 63. A toner image is formed by supplying toner from the developing device 64. After the toner image is transferred to the intermediate transfer belt 75 of the transfer unit 53, the toner remaining on the surface of the photosensitive drum 61 is removed by the cleaning unit 65. In the toner image forming means 52, this series of toner image forming operations is repeatedly executed.

  The charging device 62, the developing device 64, and the cleaning unit 65 are arranged in the order of description in the rotation direction of the photosensitive drum 61. The charging device 62 is disposed below the cleaning unit 65 in the vertical direction.

  The photosensitive drum 61 is a component that is responsible for forming a latent image by charging and exposure. Although it is an insulative part, it exhibits electrical conductivity when irradiated with light, and forms an electrical image called an electrostatic latent image on its surface.

  The photosensitive drum 61 is supported by driving means (not shown) so as to be rotatable around an axis, and includes a conductive substrate (not shown) and a photosensitive layer formed on the surface thereof.

  The charging device 62 is a device that charges the surface of the photosensitive drum 61 to a predetermined polarity and potential. As the charging device 62, a charging brush type charger, a charger type charger, a sawtooth type charger, an ion generator, or the like can be used. In this embodiment, the charging device 62 faces the photosensitive drum 61 and is arranged with a gap from the surface of the photosensitive drum 61 along the longitudinal direction of the photosensitive drum 61, but is not limited thereto. For example, a charging roller may be used as the charging device 62, and the charging roller may be disposed so that the charging roller and the photosensitive drum 61 are in pressure contact with each other, or a contact charging type charger such as a charging brush or a magnetic brush may be used. Good.

  The exposure unit 63 separates image information into light of each color b, c, m, and y in the unit, and the surface of the photosensitive drum 61 charged to a uniform potential by the charging device 62 is irradiated with light of each color. It is an apparatus that exposes and forms an electrostatic latent image on its surface.

  The exposure unit 63 is arranged so that the emitted light of each color passes between the charging device 62 and the developing device 64 and is irradiated on the surface of the photosensitive drum 61. As the exposure unit 63, for example, a laser scanning unit including a laser irradiation unit and a plurality of reflection mirrors can be used. In addition, a unit in which an LED (Light Emitting Diode) array, a liquid crystal shutter, and a light source are appropriately combined may be used.

  FIG. 4 is a cross-sectional view illustrating a configuration of the developing device 64 of the image forming apparatus 100. The developing device 64 is a device that develops an electrostatic latent image into a toner image using a one-component developer or a two-component developer containing toner.

  Since the developing device 64 performs development using the developer containing the toner capable of maintaining stable charging characteristics in a high humidity environment, a stable and high-quality toner image is formed on the photosensitive drum 61. can do.

  The developing device 64 includes a developing tank 70 and a toner hopper 71. The developing tank 70 is disposed so as to face the surface of the photosensitive drum 61, and supplies the toner accommodated therein to the surface of the photosensitive drum 61. The developing tank 70 accommodates roller members such as a developing roller 72, a supply roller 73, and a stirring roller 74 or a screw member, and supports each member so as to be rotatable. There is an opening on the side of the developing tank 70 facing the photosensitive drum 61, and a developing roller 72 is provided at a position facing the photosensitive drum 61 through the opening.

  The developing roller 72 is a roller-like member that supplies toner to the electrostatic latent image on the surface of the photosensitive drum 61 at the pressure contact portion or the closest portion to the photosensitive drum 61. A potential having a polarity opposite to the charging potential of the toner is applied to the surface of the developing roller 72 as a developing bias voltage (hereinafter referred to as “developing bias”). As a result, the toner on the surface of the developing roller 72 is smoothly supplied. Further, the toner supply amount (toner adhesion amount) can be controlled by changing the developing bias value.

  The supply roller 73 is a roller-like member provided facing the developing roller 72 and supplies toner to the periphery of the developing roller 72.

  The stirring roller 74 is a roller-like member provided facing the supply roller 73, and supplies the toner newly supplied from the toner hopper 71 into the developing tank 70 to the periphery of the supply roller 73.

  The toner hopper 71 is provided so that a toner replenishing port provided at a lower portion in the vertical direction and a toner receiving port provided at an upper portion in the vertical direction of the developing tank 70 communicate with each other. Replenish. Note that the developing device may be configured to directly replenish toner from each color toner cartridge without using the toner hopper 71.

  The cleaning unit 65 is a device that removes the toner remaining on the surface of the photosensitive drum 61 after the toner image is transferred to the recording sheet P and cleans the surface of the photosensitive drum 61. For the cleaning unit 65, for example, a plate-like member such as a cleaning blade is used. In the image forming apparatus 100 of the present embodiment, an organic photoreceptor is mainly used as the photoreceptor drum 61. Since the surface of the organic photosensitive drum is mainly composed of a resin component, ozone generated by corona discharge of the charging device is chemically acted and the surface is likely to deteriorate. However, the deteriorated surface portion is worn due to the rubbing action by the cleaning unit 65 and is gradually but surely removed. Therefore, the problem of surface deterioration due to ozone or the like is solved, and the charged potential can be stably maintained over a long period of time. In the present embodiment, the cleaning unit 65 is provided, but the cleaning unit 65 may not be provided.

  The transfer unit 53 is disposed above the photosensitive drum 61, and includes an intermediate transfer belt 75, a driving roller 76, a driven roller 77, an intermediate transfer roller 78 (b, c, m, y), and a transfer belt cleaning unit. 79 and a transfer roller 80. In the transfer unit 53, the toner image is transferred to the intermediate transfer belt 75 at the press contact portion between the photosensitive drum 61 and the intermediate transfer roller 78. The transferred toner image is conveyed to the pressure contact portion between the transfer roller 80 and the drive roller 76 by the intermediate transfer belt 75 and transferred to the recording sheet P.

  The intermediate transfer belt 75 is an endless belt member that is stretched by a driving roller 76 and a driven roller 77 to form a loop-shaped movement path, and rotates in the direction of arrow Y. The intermediate transfer roller 78 is disposed to face the photosensitive drum 61 with the intermediate transfer belt 75 interposed therebetween. When the intermediate transfer belt 75 passes through the photosensitive drum 61 in contact, a potential having a polarity opposite to the charging polarity of the toner on the drum surface is applied as a transfer bias from the intermediate transfer roller 78, and the toner image is transferred to the photosensitive drum. 61 is transferred onto the intermediate transfer belt 75 from the surface.

  In the case of a full-color image, each color toner image formed on each photoconductor drum 61 is sequentially transferred onto the intermediate transfer belt 75 to form a full-color toner image. The driving roller 76 is provided so as to be rotatable about its axis by driving means (not shown), and the intermediate transfer belt 75 is rotated in the direction of arrow Y by the rotation. The driven roller 77 is provided so as to be driven to rotate following the rotation of the driving roller 76, and applies a constant tension to the intermediate transfer belt 75 so as not to be loosened. The intermediate transfer roller 78 is provided in pressure contact with the photosensitive drum 61 via the intermediate transfer belt 75 and rotatable about its axis by a driving means (not shown). Further, as described above, the intermediate transfer roller 78 is connected to a power source (not shown) for applying a transfer bias, and transfers the toner image on the surface of the photosensitive drum 61 to the intermediate transfer belt 75.

  The transfer belt cleaning unit 79 is provided so as to face the driven roller 77 through the intermediate transfer belt 75 and to contact the outer peripheral surface of the intermediate transfer belt 75. Since the toner adhering to the intermediate transfer belt 75 due to contact with the photosensitive drum 61 causes the back surface of the recording sheet P to be contaminated, the toner on the surface of the intermediate transfer belt 75 is removed and collected by the transfer belt cleaning unit 79. .

  The transfer roller 80 is provided so as to be in pressure contact with the drive roller 76 via the intermediate transfer belt 75 and to be rotatable about an axis by drive means (not shown). At the pressure contact portion (transfer nip portion) between the transfer roller 80 and the drive roller 76, the toner image carried and conveyed by the intermediate transfer belt 75 is transferred to the recording sheet P fed from the recording sheet supply means 55 described later. Transcribed. The recording sheet P to which the toner image has been transferred is fed to the fixing device 54 by the recording sheet supply means 55.

  The fixing device 54 is a sheet conveying device 90 that conveys the recording sheet P holding the toner image, and a fixing device that heats the toner on the recording sheet P conveyed by the sheet conveying device 90 and is not in contact with the recording sheet P. A laser device 95 is provided. 5A to 5C show a more detailed configuration of the fixing device 54. FIG. 5A is a front view of the fixing device 54, FIG. 5B is a top view of the fixing device 54 viewed from the direction I in FIG. 5A, and FIG. FIG. 6 is a front view of the fixing device 54 as viewed from the II direction in FIG.

  The sheet conveying device 90 includes an endless belt 91, and a driving roller 92 and a driven roller 93 that rotatably transfer the endless belt 91. The driving roller 92 and the driven roller 93 are arranged side by side in the horizontal direction, and the endless belt 91 spanned between them conveys the recording sheet P in the horizontal direction. The endless belt 91 can be made of a heat resistant resin such as polyimide, for example.

  On the other hand, the laser device 95 includes a laser light source 96 that generates laser light, and a rotary polygon mirror 97 that reflects the laser light emitted from the laser light source 96 and performs scanning exposure on the endless belt 91. The rotary polygon mirror 97 is formed of, for example, a regular hexahedron, and rotates at a constant speed in the arrow Z direction shown in FIG. A collimator lens, a cylinder lens, or the like can be provided in the optical path between the laser light source 96 and the rotary polygon mirror 97. Further, an fθ lens, a folding mirror, a reflection mirror, or the like can be provided between the rotary polygon mirror 97 and the endless belt 91.

The laser device 95 irradiates the toner on the recording sheet P with laser light, so that the toner can be fixed to the recording sheet P by a non-contact method. The laser device 95 can irradiate the toner forming portion on the recording sheet P with high-intensity laser light in a short time. The laser light source 96 of the laser device 95 is preferably light having a wavelength of 780 nm or more and 1000 nm or less. As the intensity of the laser, it is preferable fixing exposure energy is in the range of 1.5 W / cm ² or more 630 W / cm ² or less. When the fixing exposure energy is less than 1.5 W / cm ² , the toner is not sufficiently melted by the laser irradiation, so that the fixing rate decreases. When the fixing exposure energy exceeds 630 W / cm ² , the toner or the recording sheet is irradiated by the laser irradiation. Since the P is burnt, the fixing rate is lowered.

  The recording sheet supply means 55 includes an automatic paper feed tray 85, a pickup roller 86, a transport roller 87, a registration roller 88, and a manual paper feed tray 89. The automatic paper feed tray 85 is a container-like member that is provided in the lower part of the image forming apparatus 100 in the vertical direction and stores the recording sheet P. The recording sheet P includes plain paper, color copy paper, overhead projector sheet, postcard and the like. The pickup roller 86 takes out the recording sheets P stored in the automatic paper feed tray 85 one by one and feeds them to the paper conveyance path. The conveyance rollers 87 are a pair of roller members provided so as to be in pressure contact with each other, and convey the recording sheet P toward the registration rollers 88. The registration rollers 88 are a pair of roller members provided so as to be pressed against each other, and the toner image carried on the intermediate transfer belt 75 is conveyed to the transfer nip portion of the recording sheet P fed from the conveyance roller 87. In synchronism with this, the sheet is fed to the transfer nip portion. The manual paper feed tray 89 is a device that takes the recording sheet P into the image forming apparatus 100 by manual operation, and the recording sheet P taken from the manual paper feed tray 89 passes through the paper conveyance path by the conveyance roller 87. Then, it is fed to the registration roller 88. According to the recording sheet supply means 55, the toner image carried on the intermediate transfer belt 75 is conveyed to the transfer nip portion of the recording sheet P supplied one by one from the automatic paper feed tray 85 or the manual paper feed tray 89. The paper is fed to the transfer nip portion in synchronization with the transfer.

  The discharge unit 56 includes a conveyance roller 87, a discharge roller 98, and a discharge tray 99. The conveyance roller 87 is provided on the downstream side of the fixing device 54 in the paper conveyance direction, and conveys the recording sheet P on which the image is fixed by the fixing device 54 toward the discharge roller 98. The recording sheet P on which the image is fixed is discharged by a discharge roller 98 to a discharge tray 99 provided on the upper surface in the vertical direction of the image forming apparatus 100, and a series of image forming operations by the image forming apparatus 100 is completed.

  Note that the image forming apparatus 100 of this embodiment includes a control unit (not shown). For example, the control unit is provided in an upper part of the internal space of the image forming apparatus 100 and includes a storage unit, a calculation unit, and a control unit. In the storage unit of the control means, various setting values via an operation panel (not shown) arranged on the upper surface of the image forming apparatus 100, detection from sensors (not shown) arranged at various locations inside the image forming apparatus 100, etc. As a result, image information from an external device is input. In addition, programs for executing various means are written. Examples of the various means include a recording sheet determination means, an adhesion amount control means, and a fixing condition control means. As the storage unit, those commonly used in this field can be used. For example, a read only memory (ROM), a random access memory (RAM), a hard disk drive (HDD), or the like can be used.

  The external device can be an electric / electronic device that can form or acquire image information and can be electrically connected to the image forming apparatus 100. For example, a computer, a digital camera, a television receiver, A video recorder, a DVD (Digital Versatile Disc) recorder, an HDDVD (High-Definition Digital Versatile Disc), a Blu-ray disc recorder, a facsimile device, a portable terminal device, and the like can be used. The arithmetic unit takes out various data (image formation command, detection result, image information, etc.) written in the storage unit and programs of various means, and performs various determinations. The control unit sends a control signal to the corresponding device according to the determination result of the calculation unit, and performs operation control. The control unit and the calculation unit include a processing circuit realized by a microcomputer, a microprocessor, or the like provided with a central processing unit (CPU). The control means includes a main power supply together with the processing circuit described above, and the power supply supplies power not only to the control means but also to each device in the image forming apparatus 100.

  According to the image forming apparatus 100 as described above, by irradiating the toner 10 on the recording sheet P with laser light, the toner 10 can be fixed on the recording sheet P by a non-contact method. As a result, it is possible to prevent image stains or paper jams due to hot offset. Furthermore, the use of the toner 10 prevents the generation of voids because the toner does not heat non-uniformly when irradiated with infrared rays. Thereby, an image having excellent saturation and lightness can be fixed on the recording sheet P.

  In the present embodiment, the image forming apparatus 100 that forms a color image has been described. However, the present invention is not limited to this, and an image forming apparatus that forms a monochrome image may be used.

  The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and the embodiments can be obtained by appropriately combining technical means disclosed in different embodiments. The form is also included in the technical scope of the present invention.

  Moreover, in this specification, glass transition temperature (Tg), melting | fusing point (Tm), and flow softening temperature (Tf) are defined as follows.

[Glass transition temperature (Tg)]
Using a differential scanning calorimeter (trade name: DSC220, manufactured by Seiko Denshi Kogyo Co., Ltd.), according to Japanese Industrial Standard (JIS) K7121-1987, 1 g of a sample is heated at a heating rate of 10 ° C. per minute and a DSC curve is measured. did. Draw the endothermic peak corresponding to the glass transition of the obtained DSC curve at a point where the slope is maximum with respect to the straight line that extends the base line on the high temperature side to the low temperature side and the curve from the rising part of the peak to the vertex. The temperature at the intersection with the tangent was determined as the glass transition temperature (Tg).

[Melting point (Tm)]
Using a differential scanning calorimeter (trade name: Diamond DSC, manufactured by Perkin Elmer Japan Co., Ltd.), according to Japanese Industrial Standard (JIS) K7121-1987, 0.01 g of a sample was obtained at a temperature of 20 ° C. to 200 ° C. per minute at 10 ° C. The temperature was raised at a rate of 50 ° C. per minute from 200 ° C. to 20 ° C., and then heated again at a rate of 10 ° C. per minute from 20 ° C. to 200 ° C. About the peak of the heat of fusion of the DSC curve obtained, the peak vertex temperature was calculated | required as melting | fusing point (Tm).

[Flow softening temperature (Tf)]
Using a flow characteristic evaluation apparatus (trade name: Flow Tester CFT-100C, manufactured by Shimadzu Corporation), a load of 10 kgf / cm 2 (9.8 × 105 Pa) was applied to give 1 g of a sample (nozzle diameter 1 mm, length 1 mm). The sample was heated at a temperature elevation rate of 6 ° C. per minute, and the temperature at which half of the sample flowed out of the die was determined to obtain the flow softening temperature (Tf).

  In this example, an infrared fixing toner was actually manufactured by the toner manufacturing method according to the present invention, and a comparative experiment was performed.

(1: Aqueous dispersion solution preparation step S1)
(1-1: Aqueous dispersion solution of binder resin)
First, an aqueous dispersion solution of a binder resin was synthesized by the following method. In an autoclave equipped with a thermometer and a stirrer, 113 parts by weight of dimethyl terephthalate, 75 parts by weight of dimethyl isophthalate, 6 parts by weight of 5-sodiumsulfodimethylisophthalate, 97 parts by weight of ethylene glycol, propylene glycol Is added to 0.1 parts by weight of tetrabutoxy titanate as a catalyst, and the mixture is stirred for 120 minutes while being heated to 150 ° C. or higher and 230 ° C. or lower. Then, it heated to 250 degreeC, the pressure of the reaction system was pressure-reduced to 1 mmHg or more and 10 mmHg or less, it stirred for about 1 hour, and it was made to react further, and the polyester resin which is binder resin was obtained.

  The obtained polyester resin had a number average molecular weight of 5700, a glass transition point of 64 ° C., a sodium sulfonate group equivalent: 89 meq / kg, an acid value: 2.2 mgKOH / g, and a reduced viscosity: 0.332. The molecular weight is determined by GPC (gel permeation chromatography), the glass transition point is determined by DSC (differential scanning calorimeter), the sodium sulfonate group equivalent is determined by sulfur, the acid value is determined by acid-base titration, and the reduced viscosity is 0.01 g of the polyester resin was dissolved in 250 cc of a mixed solvent of phenol / tetrachloroethane (weight ratio 6: 4), and measured using an Ostwald viscometer at a measurement temperature of 30 ° C.

  Furthermore, 100 parts by weight of the polyester resin obtained by the above synthesis method and 75 parts by weight of butyl cellosolve were added to a four-necked 10 liter separable flask equipped with a thermometer, a condenser and a stirring blade, and stirred at 70 ° C. And dissolved.

  Next, after adding 500 weight part of 70 degreeC ionic water and making it disperse | distribute to water, it distilled and distilled until the fraction temperature reached 100 degreeC with the flask for distillation. Thereafter, pure water was added to adjust the solid content concentration to 30% to obtain an aqueous dispersion of the binder resin. The number average particle size of the binder resin present in the obtained aqueous dispersion of the binder resin was 0.1 μm.

(1-2: Aqueous dispersion of colorant)
Next, an aqueous dispersion solution of the colorant was synthesized by the following method. 50 parts by weight of a cyan pigment (manufactured by BASF: Eupolene Blue 69-1501), 5 parts by weight of an anionic surfactant (Neogen R, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), and 223 parts by weight of ion-exchanged water Dispersion was carried out with a homogenizer (manufactured by Polytron, PT3000) for 20 minutes, and further dispersed with an ultrasonic homogenizer to obtain an aqueous dispersion of a colorant having a number average particle size of 0.2 μm.

(1-3: Aqueous dispersion solution of release agent)
Next, an aqueous dispersion solution of the release agent was synthesized by the following method. 50 parts by weight of paraffin wax (manufactured by Nippon Seiwa Co., Ltd., HNP10, melting point 72 ° C.), 5 parts by weight of an anionic surfactant (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., Neogen R), and 161 parts by weight of ion-exchanged water And a homogenizer (PT3000, manufactured by Polytron) while being heated to 95 ° C. to obtain an aqueous dispersion solution of a release agent having a number average particle diameter of 0.3 μm.

(2: Aqueous dispersion solution mixing step S2)
Next, the aqueous dispersion solution of the binder resin, the aqueous dispersion solution of the colorant, and the aqueous dispersion solution of the release agent obtained in the aqueous dispersion solution preparation step S1 have a solid content concentration of 90% by weight, 5%, respectively. The aqueous dispersion mixed liquid was obtained by mixing so as to be 5% by weight and 5% by weight.

(3: Colored resin particle forming step S3)
Next, while stirring the aqueous dispersion mixed solution obtained in the aqueous dispersion mixing step S2 with a homogenizer (manufactured by Polytron, PT3000: rotation speed 2000 rpm), a 0.1 wt% magnesium sulfate aqueous solution as a flocculant is dropped. did. Thereafter, the aqueous dispersion mixture was stirred for 1 hour to obtain an aqueous dispersion of colored resin particles in which colored resin particles having a number average particle size of 5.6 μm were dispersed.

(4: Coating layer forming step S4)
Next, an aqueous dispersion solution of fine resin particles and an aqueous dispersion solution of an infrared absorber to be mixed with the aqueous dispersion solution of colored resin particles obtained in the colored resin particle formation step S3 were prepared by the following method.

(4-1: Aqueous dispersion of resin fine particles)
A method for preparing an aqueous dispersion of resin fine particles is as follows. In an autoclave equipped with a thermometer and a stirrer, 137 parts by weight of dimethyl terephthalate, 55 parts by weight of dimethyl isophthalate, 68 parts by weight of ethylene glycol, and an average molecular weight of ethylene oxide adduct of bisphenol A 350) 75 parts by weight and 0.1 part by weight of tetrabutoxy titanate were charged, and the ester exchange reaction was performed by heating at 150 ° C. or higher and 220 ° C. or lower for 180 minutes.

  Next, after raising the temperature to 240 ° C., the pressure of the system was gradually reduced to 30 mm after 30 minutes, and the reaction was continued for 70 minutes. Thereafter, the inside of the autoclave was replaced with nitrogen gas to obtain atmospheric pressure. While maintaining the temperature at 200 ° C., 2 parts by weight of trimellitic anhydride was added, and the reaction was performed for 70 minutes to obtain a copolyester resin. The obtained copolyester resin had a glass transition point of 64 ° C., an acid value of 21.4 mgKOH / g, and a number average molecular weight of 3800.

  Furthermore, 48 parts by weight of butanol, 12 parts by weight of methyl ethyl ketone, and 20 parts by weight of isopropanol were added to 100 parts by weight of the obtained polyester resin, and dissolved at 70 ° C.

  Next, an aqueous solution of sodium hydroxide is added so that the acid value of the copolymerized polyester is equal, and the mixture is stirred for 30 minutes while maintaining 70 ° C. Then, 300 parts by weight of water at 70 ° C is added, and An aqueous fine dispersion was obtained. The obtained copolyester aqueous dispersion is placed in a distillation flask and distilled until the fraction temperature reaches 100 ° C., then cooled, the solid content is adjusted with deionized water, and finally, resin fine particles. As a result, an aqueous dispersion solution of a self-dispersing polyester resin having a solid content concentration of 30% was removed. The number average particle diameter of the resin fine particles present in the obtained aqueous dispersion of resin fine particles was 0.03 μm.

(4-2: Aqueous dispersion of infrared absorber)
The preparation method of the aqueous dispersion of the infrared absorber is as follows. An infrared absorbent (NK-4680, manufactured by Hayashibara Biochemical Laboratories) was prepared, and the infrared absorbent NK-4680 was suspended and dispersed in water to prepare an aqueous dispersion medium of infrared absorbent fine particles. 10 parts by weight of an infrared absorber (NK-4680, manufactured by Hayashibara Biochemical Laboratories), 5 parts by weight of an anionic surfactant (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., Neogen R), and 223 parts by weight of ion-exchanged water Were dispersed for 20 minutes with a homogenizer (manufactured by Polytron, PT3000), and further dispersed with an ultrasonic homogenizer to obtain an aqueous dispersion of an infrared absorbent having a particle size of 0.2 μm.

  Next, the aqueous dispersion solution of the colored resin particles obtained in the colored resin particle formation step S3, the aqueous dispersion solution of the resin fine particles prepared by the above-described method, and the aqueous dispersion solution of the infrared absorber have a solid content concentration of 100 respectively. Parts by weight, 10 parts by weight, and 0.5 parts by weight, 0.1% by weight aqueous magnesium sulfate solution as a flocculant was dropped little by little, and the mixture was stirred for 1 hour to form agglomerated coated particles. .

  Next, the aqueous dispersion containing the agglomerated coated particles is heated to 75 ° C. and stirred for 30 minutes, and then the aqueous dispersion is heated to 90 ° C. and stirring is further continued for 30 minutes. A well-organized agglomerated coated particle was formed.

(5: Filtration washing step S5)
Next, the supernatant liquid of the aqueous dispersion containing the aggregated coated particles was exchanged with pure water three times, and then a hydrochloric acid aqueous solution having a pH of 2 was added. Thereafter, the agglomerated coated particles were washed twice with pure water and filtered to take out wet cake-like agglomerated coated particles of the toner 10.

  In addition, the water of electrical conductivity 0.5 microsiemens / cm prepared using the ultrapure water manufacturing apparatus (The ADVANTEC company_made: Ultra Pure Water System CPW-102) was used for the pure water used for washing | cleaning.

(6: Drying step S6)
Next, the wet cake-like agglomerated coated particles of the toner taken out using a vacuum dryer were dried to produce the toner of Example 1 having a number average particle diameter of 6 μm. The particle diameter of the toner of Example 1 was measured using Coulter Multisizer II (manufactured by Coulter). Further, when the dispersion state of the colorant 13 and the release agent and the infrared absorber 16 of the obtained toner is observed using a transmission electron microscope, non-uniform aggregation and aggregates of 0.3 μm or more are not observed. It was confirmed that the dispersion was uniform.

(7: External addition step S7)
Next, 0.7 parts by weight of hydrophobic silica fine particles having an average primary particle diameter of 12 nm and 1.2 parts by weight of hydrophobized titanium oxide fine particles having an average primary particle diameter of 30 nm are added to 100 parts by weight of the obtained toner of Example 1. The toner was externally added using a Henschel mixer for 3 minutes at a peripheral speed of 40 m / sec.

  The externally added toner obtained through the above steps and a silicon-coated ferrite carrier having an average particle diameter of 40 μm are mixed by a ball mill, and two components having a toner concentration of 8 wt% and a charge amount of 28.5 μc / g. A developer was prepared.

  Further, a toner as a comparative example was manufactured by the following method. 100 parts by weight of a polyester resin used in the production of the toner of Example 1, 0.5 parts by weight of an infrared absorber (NK-4680, manufactured by Hayashibara Biochemical Laboratories), and a cyan pigment (manufactured by BASF: Eupolene Blue 69- 1501) and 5 parts by weight of paraffin wax (manufactured by Nippon Seiwa Co., Ltd., HNP10, melting point: 72 ° C.) were mixed for 3 minutes with a Henschel mixer at a peripheral speed of 40 m / sec to obtain a raw material mixture. .

  The obtained raw material mixture was melt-kneaded and dispersed using a twin-screw extruder (trade name: PCM-30, manufactured by Ikegai Co., Ltd.) to prepare a resin kneaded product. The operating conditions of the twin screw extruder were a cylinder set temperature of 110 ° C., a barrel rotation speed of 300 revolutions per minute (300 rpm), and a raw material supply speed of 20 kg / hour. The obtained toner kneaded product was cooled with a cooling belt and then coarsely pulverized with a speed mill having a φ2 mm screen.

  The resulting coarsely crushed material is pulverized with a jet type pulverizer (trade name: IDS-2, manufactured by Nippon Pneumatic Industry Co., Ltd.), and further finely divided with an elbow jet classifier (trade name, manufactured by Nittetsu Mining Co., Ltd.). The toner of Comparative Example 1 having a number average particle diameter of 6 μm was obtained by removing the coarse powder.

  In addition, toner particles having a number average particle diameter of 6 μm were prepared in the same manner as in Comparative Example 1 except that no infrared absorber (NK-4680, manufactured by Hayashibara Biochemical Laboratories) was added as the toner of Comparative Example 2. The toner of Comparative Example 2 was obtained by externally adding 0.5 part by weight of an infrared absorber (NK-4680, manufactured by Hayashibara Biochemical Laboratories). As an external addition condition, the mixture was stirred for 3 minutes at a peripheral speed of 40 m / sec using a Henschel mixer.

  In Table 1, for the two-component developer using the toner of Example 1 and the two-component developer using each toner of Comparative Examples 1 and 2, fixability, storage stability, presence or absence of voids, The result of evaluating the presence or absence of streaks and fog, and aging is shown. The evaluation method for each evaluation item is as follows.

(Fixability)
A fixing device of a commercial copying machine (trade name: MX-2700, manufactured by Sharp Corporation) is used as a fixing device 54 shown in FIGS. 5 (a) to 5 (c) under the following conditions. Fixing was performed using a semiconductor laser.

  In this experiment, the semiconductor laser wavelength was set to 808 nm, the output was set to 30 W, and the scan speed was set to 7100 mm / s.

  The DC bias value of the bias voltage applied to the developer carrying member was appropriately changed according to the charge amount of the toner in each developer, and was adjusted so that the image density of the solid image became a specified value. Further, the toner consumption amount due to visible image formation was detected by a toner density sensor as a change in toner density. Since the consumed toner is replenished from the toner hopper until the specified toner concentration is reached, the respective toner concentrations in the two-component developer in the developing unit are kept substantially constant.

  By changing the laser output value in the range of 10 W or more and 30 W or less, the temperature in the vicinity of the fixing surface was changed every 5 ° C. within the range of 100 to 180 ° C., and image samples were obtained.

  The image fixability was evaluated as follows. First, the surface of the fixed image sample is rubbed three times with a sand eraser loaded with a load of 1 kg in a Gakushin fastness tester, and the optical reflection density (image density) before and after rubbing is measured by a reflection densitometer (manufactured by Macbeth). ). Next, the fixing rate (%) was calculated by the following formula, the fixing temperature when the fixing rate exceeded 70% was determined, and evaluated according to the following criteria.

Fixing rate (%) = [(Image density after rubbing) / (Image density before rubbing)] × 100
In Table 1, when the fixing temperature is less than 120 ° C. and the fixing property is very good, the fixing temperature is 120 ° C. or more and less than 140 ° C., the fixing property is good, and the image fixing rate is problematic. ◯ when there is no extent, Δ when the fixing temperature is 140 ° C. or higher and lower than 160 ° C., and the fixing rate of the image is within the practical range, and the fixing temperature is 160 ° C. or higher. The case where the fixing property was insufficient was evaluated in four stages, with x being the case.

(Storage stability)
10 g of each toner added up to the external additive is placed in a glass bottle and allowed to stand for 48 hours in an environment at a temperature of 60 ° C., then the toner in the glass bottle is visually observed, and the storage stability is evaluated by the amount of toner aggregated. did.

  In Table 1, when there is no agglomerated toner and storage stability is good, ○, when agglomerated toner is scattered, but when there is no problem in practical use, Δ, when a large amount of agglomerated toner is present, storage stability The evaluation was made in three stages, with x being insufficient.

(With or without voids)
Next, the presence or absence of voids in the image sample after fixing was visually observed. In Table 1, a case where almost no white spots are observed in the sample image portion, a case where one or two white portions are generated in the sample image portion, and a case where three or more white portions are generated in the sample image portion. The evaluation was made in three stages, with x being the case.

(Stripes, presence of fogging)
The fixed image after fixing is visually observed for the presence of streaks and fog. Table 1 shows that there are almost no streaks or fog in the sample image area, and one or two streaks or fog occurs in the sample image area. The evaluation was made in three stages, where Δ was the case where the mark was made and Δ was the case where three or more streaks or fogging occurred in the sample image portion.

(aging)
20,000 images having a printing rate of 10% were continuously printed. The DC bias value of the bias voltage applied to the developer carrying member was appropriately changed according to the charge amount of the toner in each developer, and was adjusted so that the image density of the solid image became a specified value. The toner consumption amount due to visible image formation is detected by a toner density sensor as a change in toner density. Since the consumed toner is replenished from the toner hopper until the specified toner concentration is reached, the toner concentration in the two-component developer inside the developing unit is kept substantially constant.

  Compare the sample image portion of each toner at the beginning of printing with the sample fixing portion at the time of printing 20,000 sheets. If the fixing property or image quality does not change, ○. And evaluated in two stages.

  As shown in Table 1, the toner of Example 1 was able to obtain the best results in all evaluations, and no defect was found in the aging test for 20,000 sheets. This is because, in the toner of Example 1, since the infrared absorber is uniformly dispersed on the toner surface, energy efficiency is high, and voids due to uneven heat generation of the toner due to aggregation of the infrared absorber are generated. This is thought to be because there was not.

  On the other hand, the toners of Comparative Examples 1 and 2 were the same as Example 1 only in the storage stability of the toner, but in other evaluations, the dispersibility of the infrared absorber was poor, and voids due to aggregation, etc. Only the lowest-ranked evaluation was obtained due to the influence of. Further, in the aging test of 20,000 sheets, the fixing property and the image quality were inferior. Compared with the toner of Example 1, the toners of Comparative Examples 1 and 2 have a lower number of infrared absorbers present on the toner surface, and the dispersibility of the infrared absorbers is lower, so that the energy efficiency is higher. This is considered to be because voids were generated due to non-uniform heat generation due to aggregation of the infrared absorber.

  The present invention can be used for an infrared fixing type fixing device used in an electrophotographic image forming apparatus and an image forming apparatus provided with the fixing device.

DESCRIPTION OF SYMBOLS 1 Manufacturing method of infrared fixing toner 10 Toner 11 Colored resin particle 12 Binder resin 13 Colorant 14 Coating layer (resin coating layer)
15 resin fine particles 16 infrared absorber 100 image forming apparatus P recording sheet S1 aqueous dispersion solution preparation step S2 aqueous dispersion solution mixing step S3 colored resin particle forming step S4 coating layer forming step (film forming step)
S5 Filtration washing process S6 Drying process S7 External addition process

Claims (6)

A method for producing an infrared fixing toner comprising: colored resin particles containing at least a colorant; and a resin coating layer containing at least an infrared absorber for coating the surface of the colored resin particles,
An aqueous dispersion preparation step for preparing an aqueous dispersion containing colored resin particles, resin fine particles, and infrared absorbent fine particles;
By heating the aqueous dispersion or adding an aggregating agent to the aqueous dispersion, the resin fine particles and the infrared absorbent fine particles are aggregated on the surface of the colored resin particles to cover the surface, and the resin And a film forming step of forming a coating layer.   2. The method for producing an infrared fixing toner according to claim 1, wherein the infrared absorber is a cyanine compound. The method for producing an infrared fixing toner according to claim 1, wherein the number average particle diameter of the colored resin particles is 2 μm or more and 10 μm or less.
Is preferred.   4. The method for producing an infrared fixing toner according to claim 3, wherein the resin fine particles have a number average particle diameter of 0.05 μm or more and 0.5 μm or less. The resin fine particles include a resin having a carboxylate in the side chain,
The film-forming step includes a process of converting the carboxylate of the resin contained in the resin fine particles that are aggregated and coated on the surface of the colored resin particles into a carboxylic acid. 5. The method for producing an infrared fixing toner according to any one of 1 to 4.   6. The method for producing an infrared fixing toner according to claim 5, wherein the treatment for converting the carboxylate into the carboxylic acid is performed by adding an acid.

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