JP4850742B2 - Electrophotographic capsule toner - Google Patents

Description

  The present invention relates to a capsule toner for electrophotography.

  In an image forming apparatus using an electrophotographic system, generally, a charging process, an exposure process, a development process, a transfer process, a fixing process, and a cleaning process are executed to form a desired image on a recording medium. In the charging step, the photosensitive layer on the surface of the photosensitive drum is uniformly charged. In the exposure step, the electrostatic latent image is formed by projecting the signal light of the original image onto the surface of the charged photosensitive drum. In the development step, an electrophotographic toner (hereinafter simply referred to as “toner”) is supplied to the electrostatic latent image on the surface of the photosensitive drum to form a visible image. In the transfer step, the visible image on the surface of the photosensitive drum is transferred to a recording medium such as paper or an overhead projector (OHP) sheet. In the fixing step, the visible image is fixed on the recording medium by heating, pressing, or the like. In the cleaning process, the toner remaining on the surface of the photosensitive drum after the transfer of the visible image is removed by a cleaning blade and cleaned. In an image forming apparatus using such an electrophotographic system, a one-component developer containing toner or a two-component developer containing toner and a carrier is used as a developer.

  Electrophotographic image forming apparatuses can form images with good image quality at high speed and at low cost, and are therefore used in copying machines, printers, facsimiles, and the like. As a result, the demands on image forming apparatuses have become more severe. For example, while reduction of carbon dioxide emissions is required to prevent global warming, reduction of power consumption becomes a major issue in image forming apparatuses.

  In the image forming apparatus, a method is used in which an image is formed mainly by melting and fixing toner on a recording medium using a thermoplastic resin as a binder resin. When such a method is adopted, it is generally necessary to heat the thermoplastic resin to a high temperature of about 100 ° C. or higher when melting the thermoplastic resin. A heating device such as a heater that consumes a large amount of power is used for this heating. Further, the heating device is set so as to continue to generate heat so that the fixing unit can be maintained at a constant temperature and the image formation can be resumed immediately even during the standby time when no image is formed. Depending on the image forming apparatus, there may be several hundred to several thousand images per day.

  Therefore, in the image forming apparatus, the power consumption required for fixing the toner is so large that it cannot be ignored. For this reason, development of toner having a low temperature (fixing temperature) for fixing on a recording medium is underway. Examples of the toner having a low fixing temperature include a toner using a resin material having a low glass transition point and a softening point as a binder resin, and a toner obtained by dispersing a wax having a low fixing temperature in the binder resin.

  However, although these toners are excellent in low-temperature fixability to a recording medium, there is a problem that storage stability is insufficient. For example, if toner having a low fixing temperature is stored in the developing tank for a long time, it melts and adheres to the photoconductor to cause filming, resulting in image defects and a reduction in the useful life of the photoconductor. Further, when a two-component developer is used, filming that adheres to the carrier also occurs, which also causes image defects. Further, toner aggregation (blocking) may occur in the developing tank.

  In order to solve the problem of such a toner having a low fixing temperature, a capsule toner is proposed in which a core layer containing a colorant and a binder resin is coated with a shell layer made of resin fine particles (for example, , See Patent Document 1). The capsule toner disclosed in Patent Document 1 includes a core containing a resin binder and a pigment, dye, or a mixture thereof, and a polymer shell layer. The polymer shell layer contains a polyether component selected from the group consisting of poly (ether urea), poly (ether urethane), poly (ether amide), poly (ether ester) or a mixture thereof. According to the capsule toner disclosed in Patent Document 1, the polymer shell layer contains a soft component such as a polyether component. The aim is to reduce the permeation properties and to eliminate or suppress undesirable leaching and bleeding of the core material.

  However, in the capsule toner disclosed in Patent Document 1, by using a polyether component which is a soft component in the polymer shell layer, the packaging property of the polymer shell layer is improved, while the mechanical strength of the polymer shell layer is improved. When the capsule toner is stirred during storage, the polymer shell layer is broken and the core is easily exposed. Therefore, the storage stability of the capsule toner is low.

  On the other hand, as a toner having excellent durability and storage stability, a toner using a polyether polyol resin as a binder resin has been proposed (for example, see Patent Document 2). In the toner disclosed in Patent Document 2, as a binder resin, a peak top molecular weight Mp is 3000 or more and a number average molecular weight Mn is 2700 or more in a chromatogram measured by gel permeation chromatography of a tetrohydrofuran-soluble component. It is disclosed that a polyether polyol resin is used. The dispersant is used to uniformly disperse the colorant in the toner particles, and modified polyurethane, modified polyacrylate, polyether ester type anionic active agent, and the like are used. According to the toner disclosed in Patent Document 2, toner fusion does not occur during storage, and the durability and storage stability are excellent. The reason for this is not necessarily clear, but it is presumed that the polyether polyol resin is richer in composition and more elastic than the cross-linked polyester resin.

  When a polyether polyol resin is used as the binder resin, the low temperature fixability of the toner can be improved because the softening point Tm of the polyether polyol resin is lower than, for example, the softening point Tm of the cross-linked polyester resin. However, there is a problem that high temperature offset cannot be prevented. The high temperature offset is that the melted toner adheres to a heating roller as a fixing unit. As a result, image defects such as white spots and image fogging are likely to occur in the formed image. Under the present situation where the speed of image formation is increasing, the heating roller is likely to overheat, so that the high temperature offset property is a serious problem.

JP-A-3-144461 JP 2002-91068 A

  The object of the present invention is to achieve both fixing properties and storage stability, and stably form high-quality images without image defects such as white spots and image fogging, without causing blocking or filming. It is an object of the present invention to provide an electrophotographic capsule toner.

The present invention includes a shell layer containing a polyether polyol resin and core particles containing polyester , which is a synthetic resin different from the polyether polyol resin, and has a core / shell type structure,
Including 100 parts by weight of the core particles, 5 parts by weight or more and 25 parts by weight or less of the shell layer,
The polyether polyol resin is an electrophotographic capsule toner having a hydroxyl value of 50 KOH mg / g or more and a glass transition point of 58 ° C. or more and 64 ° C. or less.

  In the present invention, the synthetic resin different from the polyether polyol resin has an acid value of 5 KOHmg / g or more and 200 KOHmg / g or less.

  In the present invention, the polyether polyol resin is an acid addition type polyether polyol resin.

  In the present invention, the polyether polyol resin has a number average molecular weight of 1000 or more and 10,000 or less.

  Moreover, the present invention is characterized in that the synthetic resin of a type different from the polyether polyol resin has a compressive strength larger than that of the polyether polyol resin.

  In addition, the present invention is characterized in that the glass transition point of the core particles is 5 to 30 ° C. lower than the glass transition point of the shell layer.

According to the present invention, in an electrophotographic capsule toner (hereinafter simply referred to as “capsule toner”) including core particles and a shell layer covering the core particle surface, a polyether polyol resin is used as a material constituting at least the shell layer. By using polyester which is a synthetic resin different from polyether polyol resin as the material constituting the core particles, it has both low-temperature fixability and good storage stability, and further, charging stability, adhesion to paper, etc. The number of images that can be formed per unit amount is higher than that of conventional toners, and a capsule toner that can form a high-quality color image that can be fixed with high strength on a recording medium such as paper can be obtained.
By using polyester as the binder resin, the coverage, which is the ratio of the weight of the shell layer in the capsule toner, can be improved. This further improves the fixing strength of the image formed of the capsule toner of the present invention on the recording medium, and is advantageous for reducing the diameter of the capsule toner of the present invention. If the diameter of the capsule toner can be further reduced, the toner consumption can be further reduced. Furthermore, since polyester is excellent in transparency and can give good powder fluidity, low-temperature fixability, secondary color reproducibility and the like to the resulting aggregated particles, it is particularly suitable when, for example, capsule toner is used as a color toner.

Further, since the polyether polyol resin is present only in the surface layer of the capsule toner of the present invention, the softening point of the capsule toner can be designed to be higher than the softening point of the polyether polyol resin. Occurrence can be prevented, and the fixing strength of the image to the recording medium can be increased. Furthermore, according to the present invention, since the fixing temperature of the capsule toner can be lowered, the temperature inside the image forming apparatus is hardly increased, and the amount of heat applied to the capsule toner in the developing tank is reduced. Therefore, charging defects due to the deterioration of the capsule toner, coarsening due to fusion between the toners, filming, blocking, and the like are further reduced, and a high-quality image with good image density and resolution can be stably formed.
Further, the polyether polyol resin has a hydroxyl value of 50 KOH mg / g or more and a glass transition point of 58 ° C. or more and 64 ° C. or less. By using such a polyether polyol resin as the shell layer, the coverage of the shell layer can be improved. In addition, the adhesive strength between the core particles and the shell layer can be increased, and the storage stability and fixability can be improved.
Moreover, since it contains 5 parts by weight or more and 25 parts by weight or less of the shell layer with respect to 100 parts by weight of the core particles, the thickness of the shell layer with respect to the size of the core particles can be within a suitable range. Thereby, the storage stability and the fixing property can be further improved.

  Further, according to the present invention, the synthetic resin different from the polyether polyol resin has an acid value of 5 KOHmg / g or more and 200 KOHmg / g or less. By using such a resin as the core particle, the adhesive strength between the core particle and the shell layer is increased, and the temporal stability and the storage stability can be improved.

  According to the invention, the polyether polyol resin is an acid addition type polyether polyol resin. The acid addition type polyether polyol resin can be produced by reacting a polyether polyol resin with an acid anhydride. It can also be produced by reacting a secondary hydroxyl group of a polyether polyol resin with a lactone and then adding an acid anhydride. Since the acid addition type polyether polyol resin contains a carboxylic acid half ester group in the molecule, it can be easily charged when it is made into a toner. Further, by including an acid addition type polyether polyol resin in the shell layer, a capsule toner can be obtained in which the charging performance is hardly lowered even under high humidity.

  According to the invention, the polyether polyol resin has a number average molecular weight of 1000 or more and 10,000 or less. In the polyether polyol resin having such a number average molecular weight, the softening point Tm and the glass transition point Tg are maintained in a suitable range, and the resin itself has high stability, so that the fixing property and the storage stability are further improved. Therefore, excellent fixability and storage stability are maintained even in the long term.

  According to the present invention, the synthetic resin of a type different from the polyether polyol resin has a compressive strength larger than that of the polyether polyol resin. Therefore, the compressive strength of the shell layer is smaller than the compressive strength of the core particles. When the compressive strength of the shell layer is smaller than the compressive strength of the core particles, the shell layer is easily broken by being pressed by a fixing unit that fixes the capsule toner by heating and pressurizing, and the capsule toner is not easily applied to the recording medium. Low temperature fixability can be improved. This makes it possible to achieve both low-temperature fixability, stability over time, and storage stability.

  Moreover, according to this invention, the glass transition point of a core particle is 5-30 degreeC lower than the glass transition point of a shell layer. Accordingly, even when the capsule toner is stored in the developing tank for a long time, the capsule toner is prevented from melting, and heat storage stability can be obtained. Moreover, since the glass transition point of the core particles is lower than the glass transition point of the shell layer, the shell layer having a high glass transition point is destroyed by being pressed by a fixing means for fixing the capsule toner by heating and pressing, The core particles having a low glass transition point are easily melted. Thereby, the low-temperature fixability of the capsule toner can be further improved.

  The electrophotographic capsule toner of the present invention (hereinafter simply referred to as “capsule toner”) is a toner having a core / shell type structure in which the surface of core particles is covered with a shell layer.

[Shell layer]
The shell layer contains a polyether polyol resin. As the polyether polyol resin, known ones can be used. For example, a polyether polyol which is a reaction product of an epoxy resin and a compound having active hydrogen having reactivity with an epoxy group (hereinafter referred to as “active hydrogen compound”). Resin. This polyether polyol resin preferably has a number average molecular weight (GPC method) of 1000 to 10,000, more preferably 2000 to 5000.
As an epoxy resin, for example, a general formula

[Wherein, R ₁ and R ₂ may be the same or different and are a hydrogen atom, a methyl group, an ethyl group or a phenyl group, and n is an integer of 0 or more. ]
Can be used (hereinafter referred to as “bisphenol-type epoxy resin (1)”). In the general formula (1), n is preferably 0-2. The number average molecular weight of the bisphenol type epoxy resin (1) by gel permeation (GPC) method is 300 to 1000, preferably 350 to 800. The epoxy equivalent of the bisphenol type epoxy resin (1) is 150 to 500 (g / eq), preferably 170 to 400 (g / eq).

  Examples of the active hydrogen compound include monohydric phenols, dihydric phenols, carboxylic acids, alcohols, and dihydric phenol alkylene oxide adducts (hereinafter referred to as “alkylene oxide adducts”).

Examples of monohydric phenols include phenol, cresol, isopropylphenol, aminophenol, nonylphenol, dodecylphenol, xylenol, p-cumylphenol, p-octylphenol, t-butylphenol, and the like. Monohydric phenols can be used alone or in combination of two or more.
Examples of dihydric phenols include general formula

[In formula, R < ₃ > and R < ₄ > may be same or different and are a hydrogen atom, a methyl group, an ethyl group, or a phenyl group. ]
And a dihydric phenol (hereinafter referred to as “dihydric phenol (2)”). Specific examples of the dihydric phenol (2) include mononuclear dihydric phenols such as hydroquinone and resorcin, 2,2-bis (4-hydroxyphenyl) propane (bisphenol A), 2,2-bis (4 -Hydroxyphenyl) methane (bisphenol F), 2,2-bis (4-hydroxyphenyl) ethane (bisphenol AD) and the like. A dihydric phenol can be used individually by 1 type, or can use 2 or more types together.

Carboxylic acids include, for example, the general formula R ₅ (COOH) _m (3)

[Wherein R ₅ represents an alkyl group having 1 to 20 carbon atoms or a phenyl group. m is an integer of 1-4. ]
(Hereinafter referred to as “carboxylic acid (3)”). In general formula (3), when m is an integer of 1 to 4, reaction control during production is facilitated. M is preferably an integer of 1 to 3.

  Specific examples of the carboxylic acid (3) include, for example, acetic acid, propionic acid, lauric acid, myristic acid, palmitic acid, stearic acid, acrylic acid, oleic acid, arachidic acid, linoleic acid, castor oil fatty acid, tall oil fatty acid, Monovalent carboxylic acids such as benzoic acid, phthalic acid, terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, succinic acid, fumaric acid, adipic acid, maleic acid, sebacic acid, decamethylenedicarboxylic acid, mesaconic acid, citraconic acid, itaconic acid , Glutaconic acid, maconic acid, 1,3-cyclohexanedicarboxylic acid, hexahydrophthalic acid, tetrahydrophthalic acid and other divalent carboxylic acids, 1,2,3-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 1,2,4-cyclohexanetricarboxylic acid, 2,5,7-naphtha Tricarboxylic acid, 1,2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylenecarboxypropane, tetra (methylenecarboxyl) methane, 1, Examples thereof include trivalent or higher polyvalent carboxylic acids such as 2,7,8-octanetetracarboxylic acid. Carboxylic acids can be used alone or in combination of two or more.

Examples of alcohols include general formula R ₆ (OH) _q (4)

[Wherein m is the same as above. R ₆ represents an alkyl group or alkylene group having 1 to 10 carbon atoms. q shows the integer of 1-20. ]
(Hereinafter referred to as “alcohol (4)”). In general formula (4), when q is an integer of 1 to 20, reaction control during production becomes easy. Moreover, q is preferably an integer of 1 to 3.

Specific examples of the alcohol (4) include, for example, methyl alcohol, ethyl alcohol, propyl alcohol, butyl alcohol, t-butyl alcohol, monohydric alcohols such as pentanol, hexanol, heptanol, octanol, ethylene glycol, diethylene glycol, polyethylene glycol 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, neopentyl glycol, 1,4-butenediol and other dihydric alcohols, sorbitol, 1,2,3,6-hexanete Trol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, sucrose, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerin, 2- Mechi Propanetriol, 2-methyl-1,2,4-butane triol, trimethylol propane, trimethylol butane, and polyhydric alcohols such as 1,3,5-trihydroxy methyl benzene. Alcohols can be used alone or in combination of two or more.
Examples of the alkylene oxide adduct include, for example, a general formula

[Wherein, R ₇ and R ₈ may be the same or different and each represents an ethylene group or a propylene group. R ₉ and R ₁₀ may be the same or different and each represents a hydrogen atom, a glycidyl group or an acid anhydride addition group. x and y represent an integer of 1 or more, and x + y is 2 to 10. ]
And an alkylene oxide adduct (hereinafter referred to as “alkylene oxide adduct (5)”).

  Specific examples of the alkylene oxide adduct (5) include, for example, polyoxyethylene- (2,0) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene- (2,2) -2, 2-bis (4-hydroxyphenyl) propane, polyoxypropylene- (1,2) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene- (1,1) -2,2-bis ( 4-hydroxyphenyl) propane, polyoxypropylene- (2,2) -polyoxyethylene- (2,0) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene- (3,3)- 2,2-bis (4-hydroxyphenyl) propane and the like can be mentioned. In the present invention, aromatic diols such as p-xylene glycol and m-xylene glycol can also be used. An alkylene oxide adduct can be used individually by 1 type, or can use 2 or more types together.

  In the present invention, an acid addition type polyether polyol resin can also be used as the polyether polyol resin. The acid addition type polyether polyol resin can be produced by reacting a polyether polyol resin and an acid anhydride. Alternatively, it can be produced by reacting a secondary hydroxyl group of a polyether polyol resin with a lactone and then adding an acid anhydride. The acid addition type polyether polyol resin contains a carboxylic acid half ester group in the molecule. The amount is 2-50 KOHmg / g as an acid value, Preferably it is 5-30 (KOHmg / g). The acid value within this range is preferable in that it can be easily charged without using a large amount of a charge adjusting agent when it is made into a toner. Further, by including an acid addition type polyether polyol resin in the shell layer, a capsule toner can be obtained in which the charging performance is hardly lowered even under high humidity.

  The softening point of acid addition type polyether polyol resin is 80-140 degreeC, Preferably it is 85 to 130 degreeC. When the softening point is within this range, the fixing start temperature can be lowered, which is preferable from the viewpoint of low-temperature fixing. The glass transition point (Tg) of the acid addition type polyether polyol resin is 50 to 90 ° C, preferably 55 to 60 ° C. When the glass transition point (Tg) is in this range, the blocking resistance under high temperature and high humidity is improved. The acid addition type polyether polyol resin has a number average molecular weight (GPC method) of usually about 1000 to 10000, preferably about 2000 to 5000. The weight average molecular weight is usually about 2000 to 80000, preferably about 5000 to 50000. When the average molecular weight is in this range, it is preferable from the viewpoint that the fixing temperature range can be adjusted.

  An acid anhydride is a compound obtained by dehydration condensation of two carboxyl groups of a polybasic acid, such as phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, benzophenone tetracarboxylic anhydride, ethylene glycol bisglycerol tris (anhydrous). Trimellitate), maleic anhydride, succinic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylnadic anhydride, alkenyl succinic anhydride, methylhexahydrophthalic anhydride methylcyclohexenetetracarboxylic acid Anhydride, chlorendic anhydride, tetrabromophthalic anhydride, etc. are mentioned. An acid anhydride can be used individually by 1 type, or can use 2 or more types together. Although the ratio of the acid anhydride to the polyether polyol resin is not particularly limited, it is preferably 1 to 20 parts by weight, more preferably 1 to 10 parts by weight with respect to 100 parts by weight of the polyether polyol resin. Thereby, an acid addition type polyether polyol having an acid value of 2 to 50 KOHmg / g is obtained.

  Examples of lactones include β-propiolactone, dimethylpropiolactone, butyrolactone, γ-valerolactone, γ-caprolactone, γ-caprolactone, γ-laurolactone, γ-palmilactone, and γ-stearo. Examples include lactone, crotraclone, α-angelilactone, β-angelilactone, σ-valerolactone, σ-caprolactone, and ε-caprolactone. Lactones can be used alone or in combination of two or more.

  In the present invention, in the synthesis of the polyether polyol resin and the acid addition type polyether polyol resin, in addition to the above-mentioned essential compounds, bifunctional epoxy resins other than the bisphenol type epoxy resin (1), polyfunctional epoxy resins, etc. One or two or more selected from epoxy resins, dihydric phenols other than dihydric phenol (2), phenolic compounds such as polyhydric phenols, and the like can be used. These epoxy resins and phenol compounds are preferably included in the polyether polyol resin in a total amount of 30% by weight or less based on the total weight of the obtained polyether polyol resin. Moreover, when using these epoxy resins and a phenol compound, it is preferable to use it so that the number average molecular weight of the obtained polyether polyol resin may become 1000-10000, Preferably it is 2000-5000.

  Examples of the bifunctional epoxy resin other than the bisphenol type epoxy resin (1) include diglycidylated etherified diphenols, glycerol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, and polypropylene. Aliphatic bifunctional epoxy resins such as glycol diglycidyl ether, polytetramethylene glycol diglycidyl ether, phthalic acid diglycidyl ester, tetrahydrophthalic acid diglycidyl ester, hexahydrophthalic acid diglycidyl ester, adipic acid diglycidyl ester, diglycidyl p -Diglycidyl esters such as oxybenzoic acid. A bifunctional epoxy resin can be used individually by 1 type, or can use 2 or more types together.

  Examples of the polyfunctional epoxy resin include polyglycidylated polyhydric phenols, glycerol polyglycidyl ether, sorbitol polyglycidyl ether, polyglycerin polyglycidyl ether, pentaerythritol polyglycidyl ether, triglycidyl tris (2-hydroxyethyl) isocyanate. Examples thereof include aliphatic polyfunctional epoxy resins such as nerate and trimethylolpropane polyglycidyl ether, and glycidylamines such as tetraglycidyldiaminodiphenylmethane, triglycidyl m-aminophenol, and tetraglycidyl m-xylylenediamine. A polyfunctional epoxy resin can be used individually by 1 type, or can use 2 or more types together.

  Examples of dihydric phenols other than dihydric phenol (2) include mononuclear dihydric phenols such as hydroquinone and resorcin, 1,4-bis [α- (4-hydroxyphenyl) -α-methylethyl] benzene, and the like. And trinuclear dihydric phenols. Divalent phenols other than the divalent phenol (2) can be used alone or in combination of two or more.

  Examples of the polyhydric phenol include phenol / formalin condensates such as phenol novolac resin and cresol novolac resin, tetra (4-hydroxyphenyl) ethane, 1,1,3-tris (4-hydroxyphenyl) propane, 1,1. , 3-tris (3,5-dimethyl-4-hydroxyphenyl) propane, 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1- [α-methyl- (4′-hydroxyphenyl) ethyl] -4- [α ′, α′-bis (4 ″ -hydroxyphenyl) ethyl] benzene, etc. The polyphenol can be used alone or in combination of two or more. Can be used together.

  The polyether polyol resin and the acid addition type polyether polyol resin can be produced by one-step polymerization and addition reaction (hereinafter referred to as “polyaddition reaction”) using the aforementioned epoxy resin and compound as raw material compounds. The polyaddition reaction is performed in a suitable solvent in the presence of a catalyst. Examples of the catalyst include tertiary metal hydroxides such as sodium hydroxide, potassium hydroxide and lithium hydroxide, alkali metal alcoholates such as sodium methylate, N, N-dimethylbenzylamine, triethylamine, pyridine and the like. Quaternary ammonium salts such as amine, tetramethylammonium chloride, benzyltriethylammonium chloride, organophosphorus compounds such as triphenylphosphine and triethylphosphine, alkali metal salts such as lithium chloride and lithium bromide, boron trifluoride, aluminum chloride And Lewis acids such as tin tetrachloride. Although the usage-amount of a catalyst is not restrict | limited in particular, It is 1-1000 ppm normally with respect to the total weight of a raw material compound, Preferably it is 5-500 ppm. Solvents include aromatic compounds such as xylene and toluene, ketones such as 2-butanone, methyl isobutyl ketone and cyclohexanone, ethers such as ethylene glycol dibutyl ether, diethylene glycol dimethyl ether, tetrahydrofuran, dioxane and anisole, N, Examples include aprotic polar solvents such as N-dimethylformamide, dimethyl sulfoxide, and 1-methyl-2-pyrrolidinone. These solvents can be used alone or in combination of two or more. The amount of the solvent used is not particularly limited, but is 1 to 100%, preferably 5 to 50% of the total weight of the raw material compound. The reaction temperature of the polyaddition reaction is appropriately selected depending on the amount of catalyst, but is usually about 120 to 180 ° C. Although the polyaddition reaction can be generally followed by measuring the epoxy equivalent, softening point, and number average molecular weight by GPC, in the present invention, when the epoxy group substantially disappears, that is, A method in which the reaction end point is the time when the epoxy equivalent is 20000 g / equivalent or more is convenient. The measuring method of epoxy equivalent is as follows.

[Epoxy equivalent]
After putting 0.2 to 5 g of a sample into a 200 ml Erlenmeyer flask, 25 ml of dioxane was added and dissolved. To this was added 25 ml of a 0.2N dioxane solution of hydrochloric acid, which was sealed and mixed well, and then allowed to stand for 30 minutes. Next, 50 ml of a toluene-ethanol mixed solution (1: 1 volume ratio) was added, and a 1/10 N aqueous sodium hydroxide solution was titrated using cresol red as an indicator. Based on the titration result, the epoxy equivalent (g / equivalent) was calculated according to the following formula.
Epoxy equivalent (g / equivalent) = 1000 × W / [(B−S) × N × F]
W: Amount of sample collected (g)
B: Amount of sodium hydroxide aqueous solution required for the blank test (ml)
S: Amount of normal sodium hydroxide aqueous solution required for sample test (ml)
N: Normality of aqueous sodium hydroxide solution F: Potency of aqueous sodium hydroxide solution

  The softening point of such a polyether polyol resin is 80 to 140 ° C, preferably 85 ° C to 130 ° C. When the softening point is within this range, the fixing start temperature can be lowered, which is preferable from the viewpoint of low-temperature fixing.

  Although the glass transition point (Tg) of the polyether polyol resin is 50 to 90 ° C, it is preferably 55 ° C or more and 65 ° C or less. When the glass transition point (Tg) is in this range, the blocking resistance under high temperature and high humidity is improved. When the glass transition point (Tg) is less than 55 ° C., the capsule toners are fused with each other during storage, which may reduce storage stability. On the other hand, when the glass transition point (Tg) exceeds 65 ° C., the adhesive strength with the core particles becomes weak, the coverage cannot be increased, and the storage stability is lowered.

  The polyether polyol resin has a number average molecular weight (GPC method) of usually about 1000 to 10000, preferably about 2000 to 5000. The weight average molecular weight is usually about 2000 to 80000, preferably about 5000 to 50000. When the average molecular weight is in this range, it is preferable from the viewpoint that the fixing temperature range can be adjusted. In addition, the polyether polyol resin having a number average molecular weight of 1000 or more and 10,000 or less maintains the softening point Tm and the glass transition point Tg within suitable ranges, and the resin itself has high stability. It can be further improved, and excellent fixability and storage stability can be maintained over the long term.

  The hydroxyl value of the polyether polyol resin is preferably 50 KOH mg / g or more, and more preferably 50 KOH mg / g or more and 200 KOH mg / g or less. When the hydroxyl value is less than 50 KOHmg / g, the adhesive strength with the core particles becomes weak, the coverage cannot be increased, and the storage stability may be lowered. The acid value of the polyether polyol resin is preferably as small as possible, and is preferably 100 KOHmg / g or less.

The compressive strength of the polyether polyol resin is preferably 0.5 kgf / mm ² or more and 20 kgf / mm ² or less. When the compressive strength of the polyether polyol resin is in such a range, the shell layer is easily broken by being pressed by a fixing unit that fixes the capsule toner by heating and pressurization, and the capsule toner with respect to the recording medium is Low temperature fixability can be improved. When the compressive strength of the polyether polyol resin is less than 0.5 kgf / mm ² , the compressive strength becomes too weak and the storage stability is lowered. When the compressive strength of the polyether polyol resin exceeds 20 kgf / mm ² , the low-temperature fixability deteriorates.

Here, the compressive strength of the resin is a value measured using a micro compression tester MCT-W500 manufactured by Shimadzu Corporation. Specifically, in an environment of 25 ° C., one resin particle as a measurement sample is compressed to a load of 1 gf at a constant load speed, and the load when the particle diameter is deformed by 10% is measured. And the particle size before compression are values calculated by substituting into the following formula. The particle size of the resin particles is a particle size obtained by a micro compression tester.
Compressive strength (kgf / mm ² )
= 2.8 × load (kgf) / {π × particle diameter (mm) × particle diameter (mm)}

  The polyether polyol resin is preferably used in the form of fine particles. The particle size of the fine particles is not particularly limited, but is preferably 30 to 500 nm, more preferably 30 to 250 nm. By using fine particles having such a particle size range, a shell layer having a uniform layer thickness can be formed on the surface of the core particle, and when the toner is fixed, it is contained in the polyether polyol resin and the core particle contained in the shell layer. It is easy to mix with synthetic resin.

  The fine particles of the polyether polyol resin can be produced according to a known method, but are preferably produced by a high pressure homogenizer method in order to obtain fine particles having a uniform shape and a narrow particle size distribution. According to the high-pressure homogenizer method, it is possible to obtain fine particles having a uniform shape, a particle size of nm units, and a narrow particle size distribution. In this specification, the high-pressure homogenizer method is a method of pulverizing or granulating a synthetic resin or the like using a high-pressure homogenizer, and the high-pressure homogenizer is an apparatus that pulverizes particles under pressure.

  As the high-pressure homogenizer, commercially available products, those described in patent literature, and the like can be used. Examples of commercially available high-pressure homogenizers include microfluidizer (trade name, manufactured by Microfluidics), nanomizer (trade name, manufactured by Nanomizer), and optimizer (trade name, manufactured by Sugino Machine Co., Ltd.). Chamber type high pressure homogenizer, high pressure homogenizer (trade name, manufactured by Rannie), high pressure homogenizer (trade name, manufactured by Sanmaru Machinery Co., Ltd.), high pressure homogenizer (trade name, manufactured by Izumi Food Machinery Co., Ltd.), nano 3000 (trade name, manufactured by Migrain Co., Ltd.) and the like. In addition, examples of the high-pressure homogenizer described in the patent literature include those described in International Publication No. 03/059497. Among these, the high-pressure homogenizer described in International Publication No. 03/059497 is preferable. An example of a method for producing resin particles using the high-pressure homogenizer is shown in FIG.

  FIG. 1 is a flowchart schematically showing a method for producing resin particles. The manufacturing method shown in FIG. 1 includes a coarse powder preparation step S1, a slurry preparation step S2, a pulverization step S3, a cooling step S4, and a decompression step S5. Among these steps, the high-pressure homogenizer method using the high-pressure homogenizer described in International Publication No. 03/059497 is each of the pulverization step S3, the cooling step S4, and the decompression step S5. Hereinafter, the manufacturing method of the resin particle shown in FIG. 1 is demonstrated concretely.

[Coarse powder preparation step S1]
In the coarse powder preparation step S1, the polyether polyol resin is coarsely pulverized to obtain a coarse powder. The polyether polyol resin coarse powder can be obtained, for example, by melt-kneading the polyether polyol resin, cooling the resulting melt-kneaded product, and pulverizing the resulting cooled solidified product. The melt-kneaded product of cycloolefin copolymer resin can be produced, for example, by melt-kneading while heating the polyether polyol resin to a temperature equal to or higher than its melting temperature. For melt kneading, a general kneader such as a twin-screw extruder, a three-roller, or a lab blast mill can be used. More specifically, for example, a uniaxial or biaxial extruder such as TEM-100B (trade name, manufactured by Toshiba Machine Co., Ltd.), PCM-65 / 87 (trade name, manufactured by Ikegai Co., Ltd.), knee dicks ( Open roll type products such as trade name, manufactured by Mitsui Mining Co., Ltd.). The melt-kneaded product of cycloolefin copolymer resin is cooled to become a solidified product. The cooled and solidified product is coarsely pulverized by a powder pulverizer such as a cutter mill, a feather mill, or a jet mill to obtain a polyether polyol resin coarse powder. The particle size of the coarse powder is not particularly limited, but is preferably about 450 to 1000 μm, more preferably about 500 to 800 μm.

[Slurry preparation step S2]
In the slurry preparation step S2, the polyether polyol resin coarse powder (hereinafter simply referred to as “coarse powder” unless otherwise specified) obtained in the coarse powder preparation step is mixed with a liquid, and the coarse powder is dispersed in the liquid. A coarse powder slurry is prepared. The liquid to be mixed with the coarse powder is not particularly limited as long as it is a liquid that does not dissolve and uniformly disperse the coarse powder, but considering the ease of process control, waste liquid treatment after all the processes, Is preferred, and water containing a dispersion stabilizer is more preferred. The dispersion stabilizer is preferably added to water before the coarse powder is added to water.

  The dispersion stabilizer is not particularly limited, and those commonly used in this field can be used. Among these, a water-soluble polymer dispersion stabilizer is preferable. Examples of the water-soluble polymer dispersion stabilizer include acrylic-based simple substances such as (meth) acrylic acid, α-cyanoacrylic acid, α-cyanomethacrylic acid, itaconic acid, crotonic acid, fumaric acid, maleic acid, maleic anhydride, and the like. Mer, β-hydroxyethyl acrylate, β-hydroxyethyl methacrylate, β-hydroxypropyl acrylate, β-hydroxypropyl methacrylate, γ-hydroxypropyl acrylate, γ-hydroxypropyl methacrylate, 3-chloroacrylate 2-hydroxypropyl, hydroxyl group-containing acrylic monomers such as 3-chloro-2-hydroxypropyl methacrylate, diethylene glycol monoacrylate, diethylene glycol monomethacrylate, glycerol monoacrylate, glycerol monomethacrylate Ester monomers such as oxalic acid esters, vinyl alcohol monomers such as N-methylol acrylamide and N-methylol methacrylamide, ethers with vinyl alcohol, vinyl methyl ether, vinyl ethyl ether, vinyl propyl ether, etc. Vinyl alkyl ether monomers, vinyl alkyl ester monomers such as vinyl acetate, vinyl propionate and vinyl butyrate, aromatic vinyl monomers such as styrene, α-methylstyrene and vinyl toluene, acrylamide and methacrylamide Amide monomers such as diacetone acrylamide and these methylol compounds, nitrile monomers such as acrylonitrile and methacrylonitrile, acid chloride monomers such as acrylic acid chloride and methacrylic acid chloride, vinyl pyridi 1 type selected from vinyl nitrogen-containing heterocyclic monomers such as vinylpyrrolidone, vinylimidazole, and ethyleneimine, and crosslinkable monomers such as ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, allyl methacrylate, and divinylbenzene (Meth) acrylic polymer containing two kinds of hydrophilic monomers, polyoxyethylene, polyoxypropylene, polyoxyethylene alkylamine, polyoxypropylene alkylamine, polyoxyethylene alkylamide, polyoxypropylene alkylamide, poly Polyoxy such as oxyethylene nonyl phenyl ether, polyoxyethylene lauryl phenyl ether, polyoxyethylene stearyl phenyl ester, polyoxyethylene nonyl phenyl ester Cellulose polymers such as ethylene polymer, methyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, polyoxyethylene lauryl phenyl ether sodium sulfate, polyoxyethylene lauryl phenyl ether potassium sulfate, polyoxyethylene nonylphenyl ether sodium sulfate, polyoxyethylene oleyl phenyl Polyoxyalkylene alkyl aryl ether sulfate such as sodium ether sulfate, polyoxyethylene cetyl phenyl ether sodium sulfate, polyoxyethylene lauryl phenyl ether ammonium sulfate, polyoxyethylene nonylphenyl ether ammonium sulfate, polyoxyethylene oleyl phenyl ether ammonium sulfate, polyoxyethylene Lauril -Polyoxyalkylene alkyl ether sulfates such as sodium tersulfate, potassium polyoxyethylene lauryl ether sulfate, sodium polyoxyethylene oleyl ether sulfate, sodium polyoxyethylene cetyl ether sulfate, ammonium polyoxyethylene lauryl ether sulfate, ammonium polyoxyethylene oleyl ether sulfate Etc. A dispersion stabilizer can be used individually by 1 type, or can use 2 or more types together. The addition amount of the dispersion stabilizer is not particularly limited, but is preferably 0.05 to 10% by weight, more preferably 0.1 to 3% by weight, based on the total amount of water and the dispersion stabilizer.

  The coarse powder of the polyether polyol resin and the liquid are mixed using a general mixer, whereby a coarse powder slurry is obtained. Here, the amount of the coarse powder added to the liquid is not particularly limited, but is preferably 3 to 45% by weight, more preferably 5 to 30% by weight, based on the total amount of the coarse powder and the liquid. The mixing of the coarse powder and water may be carried out under heating or cooling, but is usually carried out at room temperature. As the mixer, for example, a Henschel type mixing device such as Henschel mixer (trade name, manufactured by Mitsui Mining Co., Ltd.), Super Mixer (trade name, manufactured by Kawata Co., Ltd.), Mechano Mill (trade name, manufactured by Okada Seiko Co., Ltd.), etc. Ongmill (trade name, manufactured by Hosokawa Micron Corporation), hybridization system (trade name, manufactured by Nara Machinery Co., Ltd.), Cosmo system (trade name, manufactured by Kawasaki Heavy Industries, Ltd.), and the like. The coarse powder slurry thus obtained may be used as it is in the pulverization step S3. However, for example, a general coarse pulverization treatment is performed as a pretreatment, and the particle size of the coarse powder is preferably about 100 μm, more preferably 100 μm or less. You may grind | pulverize. The coarse pulverization process is performed, for example, by passing the coarse powder slurry through a nozzle under high pressure.

[Crushing step S3]
In the pulverization step S3, the coarse powder slurry obtained in the slurry preparation step S2 is passed through a pressure-resistant nozzle under heat and pressure to pulverize the coarse powder into resin fine particles, thereby obtaining a resin fine particle slurry. Although the pressure heating condition of the coarse powder slurry is not particularly limited, it is preferably pressurized to 50 to 250 MPa and heated to 50 ° C. or higher, preferably pressurized to 50 to 250 MPa and heated to 90 ° C. or higher. More preferably, it is particularly preferred to be pressurized to 50 to 250 MPa and heated to 90 to Tm + 25 ° C. (Tm: 1/2 softening temperature of polyether polyol resin by a flow tester, ° C.). If it is less than 50 MPa, the shear energy becomes small, and there is a possibility that sufficient particle size cannot be reduced. If it exceeds 250 MPa, the danger is too great in an actual production line, which is not realistic. The coarse powder slurry is introduced into the pressure-resistant nozzle from the pressure-resistant nozzle inlet at a pressure and temperature in the above-mentioned range.

  As the pressure resistant nozzle, a general pressure resistant nozzle capable of liquid flow can be used, but for example, a multiple nozzle having a plurality of liquid flow passages can be preferably used. The liquid flow passages of the multiple nozzles may be formed concentrically around the axis of the multiple nozzle, or a plurality of liquid flow passages may be formed substantially parallel to the longitudinal direction of the multiple nozzles. As an example of the multi-nozzle, there is one in which one or a plurality of liquid flow passages having an inlet diameter and an outlet diameter of about 0.05 to 0.35 mm and a length of 0.5 to 5 cm are formed, preferably about 1 to 2. It is done. Moreover, what is shown in FIG. 2 is mentioned as a pressure | voltage resistant nozzle.

  FIG. 2 is a cross-sectional view schematically showing the configuration of the pressure-resistant nozzle 1. The pressure-resistant nozzle 1 has a liquid flow passage 2 inside thereof, and the liquid flow passage 2 is bent like a bowl. The configuration of the pressure-resistant nozzle is not limited to this, and the liquid flow path may be formed linearly. The coarse powder slurry enters the flow path from the direction of the arrow 4, the coarse powder is crushed by the back pressure, and is discharged from the pressure-resistant nozzle 1 as resin particles having a smaller diameter. In the pressure-resistant nozzle 1, the inlet diameter and the outlet diameter are formed to be the same size, but the present invention is not limited to this, and the outlet diameter may be formed smaller than the inlet diameter. One pressure-resistant nozzle may be provided, or a plurality of pressure-resistant nozzles may be provided. The slurry discharged from the outlet of the pressure-resistant nozzle contains, for example, resin fine particles having a particle diameter of about 30 nm to 10 μm, and is heated to 60 to Tm + 60 ° C. (Tm is the same as above), and 50 to 200 MPa. Pressurized to the extent.

[Cooling step S4]
In the cooling step S4, the slurry in the heated and pressurized state including the resin fine particles having a reduced diameter obtained in the pulverizing step S3 is cooled. In the cooling step S4, the slurry discharged from the pressure-resistant nozzle in the previous step is cooled. For cooling, any general liquid cooler having a pressure-resistant structure can be used. Among them, a cooler having a large cooling area such as a serpentine cooler is preferable. Further, it is preferable that the cooling gradient is reduced from the inlet of the cooler to the outlet of the cooler (or the cooling capacity is lowered). As a result, the diameter of the resin fine particles can be reduced more efficiently. Moreover, the coarsening by the reattachment of resin fine particles can be prevented, and the yield of the resin fine particles can be improved. The small-sized resin fine particle-containing slurry discharged from the pressure-resistant nozzle in the previous step is introduced into the cooler from the cooler inlet, receives cooling inside the cooler having a cooling gradient, and is discharged from the cooler outlet, for example. . One or a plurality of coolers may be provided.

[Decompression step S5]
In the pressure reducing step S5, the pressure of the pressurized slurry containing the resin fine particles obtained in the cooling step S4 is reduced to a pressure that does not cause bubbling (generation of bubbles). The slurry supplied from the cooling step S4 to the decompression step S5 is in a state of being pressurized to about 5 to 80 MPa. The pressure reduction is preferably performed gradually in steps. For this decompression operation, it is preferable to use a multistage decompression device described in WO 03/059497.

  For the pressurized slurry containing resin fine particles obtained in the cooling step S4, for example, a pressure resistant pipe is provided between the cooling step S4 and the pressure reducing step S5, and a supply pump and a supply valve are provided on the pressure resistant pipe. Is supplied from the cooling step S4 to the decompression step S5 and introduced into the multistage decompression device. The multistage depressurization apparatus is formed so as to communicate with the inlet passage through which the slurry containing resin fine particles and in a pressurized state is introduced into the multistage depressurization apparatus, and the depressurized slurry containing resin fine particles is formed in the multistage depressurization apparatus. An outlet passage that discharges to the outside of the decompression device, and a multistage decompression unit that is provided between the inlet passage and the outlet passage and in which two or more decompression members are connected via a connecting member.

  In the multistage pressure reducing device, examples of the pressure reducing member used for the multistage pressure reducing means include a pipe-shaped member. An example of the connecting member is a ring-shaped seal. A multistage pressure reducing means is configured by connecting a plurality of pipe-shaped members having different inner diameters with a ring-shaped seal. For example, two to four pipe-like members having the same inner diameter are connected from the inlet passage to the outlet passage, and then one pipe-like member having a larger inner diameter than these is connected. Also, by connecting about 1 to 3 pipe-shaped members having a small inner diameter of about 5 to 20%, the slurry containing the resin fine particles flowing through the pipe-shaped member is gradually decompressed, and finally no bubbling occurs. The pressure is reduced to atmospheric pressure. A heat exchanging means using a refrigerant or a heat medium is provided around the multistage pressure reducing means, and cooling or heating may be performed according to the pressure applied to the slurry containing resin particles (hereinafter referred to as “back pressure”). Good. One or more multistage pressure reducing devices may be provided. The slurry containing resin fine particles decompressed in the multistage decompression device is discharged from the outlet passage to the outside of the multistage decompression device.

  In this way, a slurry containing resin fine particles having a particle diameter of about 30 nm to 10 μm is obtained. This slurry can be used as it is in the manufacture of capsule toner described later. Further, the resin fine particles having a reduced diameter isolated from the slurry may be newly slurried. In order to isolate the resin fine particles from the slurry, general separation means such as filtration and centrifugal separation are used. In the above granulation method, the steps from S1 to S5 may be performed only once, or after the steps from S1 to S5 are performed once, the steps from S3 to S5 may be repeated. An apparatus for carrying out the steps of S3 to S5 is commercially available, and examples thereof include NANO3000 (trade name, manufactured by Miki Co., Ltd.).

[Core particles]
The core particle contains a synthetic resin of a different type from the polyether polyol resin. The core particles used in the capsule toner of the present invention contain a binder resin and a colorant, and may further contain a release agent, a charge control agent and the like. The binder resin is a synthetic resin different from the polyether polyol resin, has a relatively good compatibility with the polyether polyol resin, and can be fixed to a recording medium at a low temperature. For example, any conventionally used binder resin for toner can be used. Specific examples include thermoplastics such as polyester, polyether, polyethersulfone, polystyrene, polyacrylic ester, styrene-acrylic acid resin, styrene-methacrylic acid resin, polyvinyl chloride, polyvinyl acetate, and polyvinylidene chloride. Examples thereof include thermosetting resins such as resin, phenol resin, epoxy resin, and polyurethane. Binder resin can be used individually by 1 type, or can use 2 or more types together.

  Among those exemplified above, it is particularly preferable to use polyester. By using polyester as the binder resin, the coverage, which is the ratio of the weight of the shell layer in the capsule toner, can be improved. This further improves the fixing strength of the image formed of the capsule toner of the present invention on the recording medium, and is advantageous for reducing the diameter of the capsule toner of the present invention. If the diameter of the capsule toner can be further reduced, the toner consumption can be further reduced. Furthermore, since polyester is excellent in transparency and can give good powder fluidity, low-temperature fixability, secondary color reproducibility and the like to the resulting aggregated particles, it is particularly suitable when, for example, capsule toner is used as a color toner.

  Furthermore, it is preferable that the synthetic resin of a kind different from the polyether polyol resin has an acid value of 5 KOHmg / g or more and 200 KOHmg / g or less. When the acid value is less than 5 KOH mg / g, the shell strength becomes weak, and when the acid value exceeds 200 KOH mg / g, the environmental resistance decreases.

  Moreover, it is preferable that the synthetic resin of a kind different from the polyether polyol resin has higher compressive strength than the polyether polyol resin. When the compressive strength of a synthetic resin of a type different from the polyether polyol resin is larger than the compressive strength of the polyether polyol resin, the compressive strength of the shell layer can be made smaller than the compressive strength of the core particles. As a result, the shell layer is easily broken when pressed by a fixing unit that fixes the capsule toner by heating and pressing, and the low-temperature fixability of the capsule toner to the recording medium can be improved.

Furthermore, the synthetic resin of a type different from the polyether polyol resin preferably has a compressive strength of 0.5 kgf / mm ² or more and 30 kgf / mm ² or less. When the compressive strength is less than 0.5 kgf / mm ² , the shell strength is insufficient, and when the compressive strength exceeds 30 kgf / mm ² , problems such as photoconductor filming occur, which is not preferable.

  As the colorant, organic dyes, organic pigments, inorganic dyes, inorganic pigments and the like commonly used in the electrophotographic field can be used.

  Examples of the black colorant include carbon black, copper oxide, manganese dioxide, aniline black, activated carbon, nonmagnetic ferrite, magnetic ferrite, and magnetite.

  Examples of yellow colorants include chrome lead, zinc yellow, cadmium yellow, yellow iron oxide, mineral fast yellow, nickel titanium yellow, navel yellow, naphthol yellow S, Hansa yellow G, Hansa yellow 10G, benzidine yellow G, and benzidine. Yellow GR, Quinoline Yellow Lake, Permanent Yellow NCG, Tartrazine Lake, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 13, C.I. I. Pigment yellow 14, C.I. I. Pigment yellow 15, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 94, C.I. I. Pigment yellow 138, and the like.

  Examples of the orange colorant include red chrome yellow, molybdenum orange, permanent orange GTR, pyrazolone orange, vulcan orange, indanthrene brilliant orange RK, benzidine orange G, indanthrene brilliant orange GK, C.I. I. Pigment orange 31, C.I. I. And CI Pigment Orange 43.

  Examples of red colorants include bengara, cadmium red, red lead, mercury sulfide, cadmium, permanent red 4R, risor red, pyrazolone red, watching red, calcium salt, lake red C, lake red D, and brilliant carmine 6B. Eosin Lake, Rhodamine Lake B, Alizarin Lake, Brilliant Carmine 3B, C.I. I. Pigment red 2, C.I. I. Pigment red 3, C.I. I. Pigment red 5, C.I. I. Pigment red 6, C.I. I. Pigment red 7, C.I. I. Pigment red 15, C.I. I. Pigment red 16, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 53: 1, C.I. I. Pigment red 57: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 123, C.I. I. Pigment red 139, C.I. I. Pigment red 144, C.I. I. Pigment red 149, C.I. I. Pigment red 166, C.I. I. Pigment red 177, C.I. I. Pigment red 178, C.I. I. And CI Pigment Red 222.

  Examples of purple colorants include manganese purple, fast violet B, and methyl violet lake.

  Examples of blue colorants include bitumen, cobalt blue, alkali blue lake, Victoria blue lake, phthalocyanine blue, metal-free phthalocyanine blue, phthalocyanine blue partially chlorinated products, first sky blue, induslen blue BC, C.I. I. Pigment blue 15, C.I. I. Pigment blue 15: 2, C.I. I. Pigment blue 15: 3, C.I. I. Pigment blue 16, C.I. I. And CI Pigment Blue 60.

  Examples of the green colorant include chrome green, chromium oxide, pigment green B, micalite green lake, final yellow green G, C.I. I. And CI Pigment Green 7.

  Examples of the white colorant include compounds such as zinc white, titanium oxide, antimony white, and zinc sulfide.

  One colorant can be used alone, or two or more different colorants can be used in combination. Moreover, even if it is the same color, 2 or more types can be used together. The amount of the colorant to be used is not particularly limited, but is preferably 0.1 to 20 parts by weight, more preferably 0.2 to 10 parts by weight with respect to 100 parts by weight of the binder resin.

  As the release agent, those commonly used in this field can be used, for example, petroleum wax such as paraffin wax and derivatives thereof, microcrystalline wax and derivatives thereof, Fischer-Tropsch wax and derivatives thereof, polyolefin wax (polyethylene wax, polypropylene Wax etc.) and derivatives thereof, low molecular weight polypropylin wax and derivatives thereof, hydrocarbon polymer waxes such as polyolefin polymer wax (low molecular weight polyethylene wax etc.) and derivatives thereof, carnauba wax and derivatives thereof, rice wax and derivatives thereof , Candelilla wax and its derivatives, plant wax such as wood wax, animal wax such as beeswax and whale wax, fatty acid amide, phenol fatty acid ester, etc. Oil-based synthetic waxes, long-chain carboxylic acids and their derivatives, long-chain alcohols and derivatives thereof, silicone polymers, such as higher fatty acids. Derivatives include oxides, block copolymers of vinyl monomers and waxes, graft modified products of vinyl monomers and waxes, and the like. The amount of the wax used is not particularly limited and can be appropriately selected from a wide range, but is preferably 0.2 to 20 parts by weight, more preferably 0.5 to 10 parts by weight, particularly preferably 100 parts by weight of the binder resin. 1.0 to 8.0 parts by weight.

  As the charge control agent, those for positive charge control and negative charge control commonly used in this field can be used. Examples of charge control agents for positive charge control include nigrosine dyes, basic dyes, quaternary ammonium salts, quaternary phosphonium salts, aminopyrines, pyrimidine compounds, polynuclear polyamino compounds, aminosilanes, nigrosine dyes and derivatives thereof, triphenylmethane Derivatives, guanidine salts, amidine salts and the like can be mentioned. Charge control agents for controlling negative charges include oil-soluble dyes such as oil black and spiron black, metal-containing azo compounds, azo complex dyes, metal salts of naphthenic acid, metal salts of salicylic acid and its derivatives (metals are metal Chromium, zinc, zirconium, etc.), fatty acid soaps, long-chain alkyl carboxylates, resin acid soaps, and the like. A charge control agent can be used individually by 1 type, or can use 2 or more types together as needed. The use amount of the charge control agent is not particularly limited and can be appropriately selected from a wide range, but is preferably 0.5 to 3 parts by weight with respect to 100 parts by weight of the binder resin.

  The core particles can be manufactured according to a general toner manufacturing method. As a general toner production method, for example, a dry method such as a pulverization method, a suspension polymerization method, an emulsion aggregation method, a dispersion polymerization method, a dissolution suspension method, and a wet emulsion method such as a melt emulsification method are used.

  According to the pulverization method, a binder resin, a colorant, a release agent, a charge control agent and other additives are mixed by a mixer such as a Henschel mixer, a super mixer, a mechano mill, and a Q type mixer, and the resulting raw material mixture is mixed. It is melt-kneaded by a kneader such as a twin-screw kneader, a single-screw kneader, or a continuous two-roll kneader, the resulting kneaded product is cooled and solidified, and the solidified product is pulverized by an air-type pulverizer such as a jet mill. The core particles can be obtained by adjusting the particle size such as classification as required.

  Further, according to the emulsion aggregation method, the binder resin particles are emulsified and dispersed in water, and further, a colorant and fine particles of a release agent, a charge control agent, etc. are dispersed in the aqueous dispersion of the binder resin particles. The core particles can be obtained by adding the aqueous dispersion to the flocculant to form aggregated particles in which the binder resin particles, the colorant and the like are aggregated, and heating the resulting aggregated particles.

  Further, according to the melt emulsification method, a kneaded product of a toner material containing a binder resin, a colorant, a release agent, a charge control agent and other additives is heated under pressure and in the presence of a dispersant in water. By performing granulation by applying a shearing force and a collision force, a toner having a narrow particle size distribution and a uniform particle size and shape can be obtained. As an apparatus for applying a shearing force and a collision force in this melt emulsification method, a high-speed rotating dispersion granulator including a rotating rotor, a plurality of tracking screens, and a fixed screen can be used.

  FIG. 3 is a top view schematically showing the configuration of the high-speed rotational dispersion granulator 11. FIG. 4 is a perspective view schematically showing the configuration of the follow-up screen 14 that is a component of the high-speed rotary dispersion granulator 11. The high-speed rotary dispersion granulator 11 includes a cylindrical pressure vessel 12 (hereinafter sometimes simply referred to as “pressure vessel 12”), a rotating rotor 13, follow-up screens 14 and 15, and a fixed screen 16.

  The cylindrical pressure resistant container 12 is a sealable container-like member having an inner space 12a composed of an outer wall 12b and both surfaces in a thickness direction (not shown). A heating means (not shown) is disposed in the vicinity of the pressure vessel 12. The pressure vessel 12 is connected to a pressurizing means (not shown), an aqueous dispersion supply pipe containing a kneaded mixture of toner raw materials, an aqueous dispersion discharge pipe containing toner particles after granulation, and the like. Furthermore, the pressure vessel 12 includes a pressure regulating valve (not shown).

  The rotary rotor 13 is supported on one or both surfaces in the thickness direction of the pressure vessel 12 in the internal space 12a of the pressure vessel 12, and has the same axis as the pressure vessel 12 and is driven by a driving means (not shown). The stirring member includes a rotating shaft 13 a provided to be rotatable in the direction of the reference numeral 18, and an integrated stirring blade 13 b extending from the peripheral surface of the rotating shaft 13 a in the radial direction of the pressure-resistant vessel 12. The peripheral speed of the rotary rotor 13 is not particularly limited, but is preferably 30 to 60 m / s. When this is converted into the number of rotations per minute of the rotary rotor 13, it is about 9600-19000 rpm.

  The follow-up screen 14 has the same axis as the pressure vessel 12 around the rotary rotor 13 and is provided so as to be able to follow the rotational drive of the rotary rotor 13, and a plurality of slits 17 capable of liquid flow are provided on the peripheral wall 14 a. It is a formed cylindrical or bowl-shaped member. Another tracking screen 15 has the same configuration as the tracking screen 14 except that it is provided around the tracking screen 14.

  The fixed screen 16 is provided around the follow-up screen 15 so as to have the same axis as the cylindrical pressure-resistant container 12, and a plurality of slits capable of liquid flow are formed on the peripheral wall in the same manner as the follow-up screens 14 and 15. It is a cylindrical or bowl-shaped member. Since the fixed screen 16 is supported on one or both surfaces in the thickness direction of the pressure vessel 12, the fixed screen 16 does not rotate following the rotation of the rotary rotor 13.

  According to the high-speed rotary dispersion granulator 11, while the internal space 12a of the pressure vessel 12 is filled with an aqueous dispersion of a dispersant containing a kneaded product of toner raw material, while heating and pressurizing to a predetermined temperature and pressure, The rotary rotor 13 is driven to rotate, and the follower screens 14 and 15 are caused to follow and rotate. The kneaded material of the toner material is given a centrifugal force by the rotation of the rotary rotor 13 and the follower screens 14 and 15, and flows in the direction from the vicinity of the axial center of the pressure-resistant container 12 toward the container outer wall 12b. Then, a shearing force is applied when passing through the liquid flow slit 17 of the following screens 14 and 15, and it collides with the fixed screen 16, or passes through the liquid flow slit (not shown) of the fixed screen 16 and the outer wall of the container. Colliding with 12b, a collision force is applied.

  As described above, the kneaded material of the toner material is repeatedly given shearing force and collision force, and the kneaded material is granulated into fine particles. A high-speed rotational dispersion granulator is described in, for example, Japanese Patent Application Laid-Open No. 2004-8898. Moreover, as a high-speed rotation dispersion type granulator, for example, a foam-less mixer (trade name, manufactured by Miki Co., Ltd.) can be used.

  Among various production methods such as the above pulverization method, suspension polymerization method, emulsion aggregation method, dispersion polymerization method, dissolution suspension method, and melt emulsification method, the core particles can be easily reduced in diameter. Since the particle size distribution width can be narrowed and the selection range of the resin is wide, the melt emulsification method, the emulsion aggregation method and the dissolution suspension method are preferable, and the melt emulsification method is particularly preferable. The particle diameter of the core particles is not particularly limited, but considering the covering of the shell layer, the volume average particle diameter is preferably 3 to 8 μm, more preferably 3 to 6 μm. Here, the volume average particle diameter is a condition using a Coulter Counter TA-III (trade name, manufactured by Coulter, Inc.), aperture diameter: 100 μm, measurement target particle diameter: 2 to 40 μm on the basis of number, and measurement particle number: 50000 count. Is measured.

  The glass transition point of the core particles is preferably 40 to 70 ° C, more preferably 50 to 60 ° C. The softening point of the core particles is preferably 80 to 140 ° C, more preferably 85 to 130 ° C.

  Moreover, it is preferable to set so that the glass transition point of a core particle may be 5-30 degreeC lower than the glass transition point of a shell layer. If it is less than 5 ° C., there is no clear difference between the melting characteristics of the core particles and the melting characteristics of the shell layer, and the low-temperature fixability and the storage stability may be insufficient in the capsule toner of the present invention. . If the difference between the two exceeds 30 ° C., it becomes difficult for the two particles to melt at the interface between the core particles and the shell layer, thereby enhancing the adhesion between the two, and the shell layer is easily peeled off from the core particles. This reduces the durability of the capsule toner. The glass transition point of the core particles can be adjusted to a desired value by appropriately selecting the type of the release agent, the amount of the release agent used, and the like when the type includes a binder resin and a release agent.

[Capsule toner]
The capsule toner of the present invention can be produced by coating a core polyol with a polyether polyol resin to form a shell layer. The coating of the polyether polyol resin on the core particles can be performed according to a known method such as a mechanofusion method, a fluidized bed coating method, or a wet coating method.

  According to the mechano-fusion method, for example, after the polyether polyol resin fine particles are electrostatically adsorbed on the surface of the core particles, the core particle surfaces are heated and pressurized by mechanical impact, and a part of the fine particles of the polyether polyol resin is obtained. Alternatively, the capsule toner of the present invention is manufactured by melting the whole amount to form a film to form a shell layer. To implement the mechanofusion method, various commercially available mechanofusion devices can be used.

  Further, according to the fluidized bed coating method, the capsule toner of the present invention is formed by forming a fluidized bed of core particles and spraying a solution of polyether polyol resin or a dispersion of polyether polyol resin fine particles into the fluidized bed. Manufactured. In order to carry out the fluidized bed coating method, for example, a fluidized bed type coating apparatus can be used.

  Examples of the wet coating method include a spray drying method, a dipping method, and a fluidized bed method. According to the spray drying method, the capsule toner of the present invention is manufactured by spray-coating a solution of the polyether polyol resin on the surface of the core particles and drying the solvent contained in the solution to form a shell layer. According to the fluidized bed method, the core particles are raised to an equilibrium height by the rising pressurized gas flow, and then the operation of spraying the polyether polyol resin solution before the core particles fall is repeated, A shell layer is formed, and the capsule toner of the present invention is manufactured. In order to carry out the wet coating method, for example, a spray coating apparatus such as a coatmizer jet coaching system (trade name, manufactured by Freund Sangyo Co., Ltd.), a spray drying apparatus such as Granurex (trade name, manufactured by Freund Sangyo Co., Ltd.), a dispa A spray coating apparatus such as a coat (trade name, manufactured by Nissin Engineering Co., Ltd.), a spray dryer or the like can be used.

  In addition, an aqueous magnesium sulfate solution or the like is added to an aqueous dispersion of core particles, polyether polyol resin particles, the same dispersion stabilizer as described above, and an appropriate surfactant (preferably anionic surfactant) with stirring. The capsule toner of the present invention in which the core particle surface is coated with the polyether polyol resin particles can also be obtained by (preferably dropping). The capsule toner can be easily isolated from the reaction system by general isolation and purification methods such as filtration, washing with pure water, and vacuum drying. The capsule toner may be produced by a method other than the above, for example, an in-situ polymerization method or a coacervation method.

  The content ratio of the shell layer in the capsule toner of the present invention is not particularly limited, but considering the compatibility between low temperature fixability and storage stability in the obtained capsule toner, the fixing strength to the recording medium, etc., the amount is 100 parts by weight of the core particles. The shell layer preferably contains 1 to 30 parts by weight, more preferably 1 to 10 parts by weight. When the shell layer is less than 1 part by weight, a portion where the core particles are not sufficiently covered by the shell layer is generated, which may hinder the charging stability and storage stability of the capsule toner. When the shell layer exceeds 30 parts by weight, the amount of the polyether polyol resin, which is the main component of the shell layer, becomes excessive, and the low-temperature fixability is impaired, and the fixing strength of the toner image composed of the capsule toner to the recording medium May be insufficient.

  The capsule toner of the present invention is adjusted so that its volume average particle diameter is preferably 4 to 10 μm, more preferably 5 to 7 μm. The particle size of the capsule toner can be adjusted by appropriately selecting the particle size of the core particles, the coating amount of the shell layer, and the like. The capsule toner of the present invention can be set to a non-offset temperature range of 130 to 190 ° C. and a fixing temperature of 150 to 160 ° C., for example. The conventional general toner has a non-offset temperature range of 150 to 210 ° C. and a fixing temperature of about 170 ° C. Therefore, the capsule toner of the present invention has a fixing temperature lower by about 10 to 20 ° C. than the general toner. It will be a thing.

  In the capsule toner of the present invention, a polyether polyol resin is used as a material constituting at least the shell layer, and a synthetic resin different from the polyether polyol resin is used as a material constituting the core particles. As a result, it has both low-temperature fixability and good storage stability, and also has excellent charging stability, adhesion to paper, etc., and the number of images that can be formed per unit amount is greater than that of conventional toners. A capsule toner capable of forming a high-quality color image that can be fixed to a medium with high strength is obtained.

  Further, since the polyether polyol resin is present only in the surface layer of the capsule toner of the present invention, the softening point of the capsule toner can be designed to be higher than the softening point of the polyether polyol resin. Occurrence can be prevented, and the fixing strength of the image to the recording medium can be increased. Furthermore, according to the present invention, since the fixing temperature of the capsule toner can be lowered, the temperature inside the image forming apparatus is hardly increased, and the amount of heat applied to the capsule toner in the developing tank is reduced. Therefore, charging defects due to the deterioration of the capsule toner, coarsening due to fusion between the toners, filming, blocking, and the like are further reduced, and a high-quality image with good image density and resolution can be stably formed.

  The capsule toner of the present invention may be subjected to surface modification using an external additive. As the external additive, known ones can be used, and examples thereof include silica, titanium oxide and the like surface-treated with silica, titanium oxide, silicone resin, silane coupling agent and the like. Further, the amount of the external additive used is preferably 1 to 10 parts by weight with respect to 100 parts by weight of the toner.

  The toner of the present invention can be used as a one-component developer or a two-component developer. When used as a one-component developer, a carrier is not used, only toner is used, a blade and a fur brush are used, a toner is frictionally charged by a developing sleeve, and the toner is attached onto the sleeve to form an image. . When used as a two-component developer, the capsule toner of the present invention is used together with a carrier. As the carrier, a known carrier can be used, and examples thereof include a single or composite ferrite composed of iron, copper, zinc, nickel, cobalt, manganese, chromium and the like and a carrier core particle whose surface is coated with a coating substance. Known coating materials can be used, such as polytetrafluoroethylene, monochlorotrifluoroethylene polymer, polyvinylidene fluoride, silicone resin, polyester resin, metal compound of ditertiary butylsalicylic acid, styrene resin, acrylic resin , Polyacid, polyvinyllar, nigrosine, aminoacrylate resin, basic dye, basic dye lake, silica fine powder, alumina fine powder, and the like, which are preferably selected according to the toner component. Moreover, a coating substance can be used individually by 1 type, or can use 2 or more types together. The average particle diameter of the carrier is preferably 10 to 100 μm, more preferably 20 to 50 μm.

(Example)
Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples. In the following, “parts” and “%” mean “parts by weight” and “% by weight” unless otherwise specified. The number average molecular weight (Mn), weight average molecular weight (Mw), glass transition point (Tg), softening point, acid value, hydroxyl value, volume average particle size, and coefficient of variation (CV value) in Examples and Comparative Examples are: Measurement was performed as follows.

[Measurement of number average molecular weight (Mn) and weight average molecular weight (Mw) by GPC]
A sample solution was prepared by dissolving 180 mg of a sample in 10 ml of tetrahydrofuran. 25 μl of this sample solution was injected into the column, and the retention time was measured under the following conditions. Moreover, the average molecular weight (Mn, Mw) of the resin sample was calculated | required in polystyrene conversion from the calibration curve which measured and prepared the retention time previously using polystyrene with a known average molecular weight as a standard substance.
Column: Guard column + GLR400M + GLR400M + GLR400 (all manufactured by Hitachi, Ltd.)
Column temperature: 40 ° C
Mobile phase (flow rate): Tetrahydrofuran (1 ml / min)
Peak detection method: UV (254 nm)

[Glass transition point (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 (carboxyl group-containing resin or water-soluble resin) is added at each temperature increase rate. The DSC curve was measured by heating at 10 ° C. for minutes. 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 point (Tg).

[Softening point]
The softening point was measured using a flow characteristic evaluation apparatus (trade name: Flow Tester CFT-100C, manufactured by Shimadzu Corporation). In a flow characteristic evaluation apparatus (flow tester CFT-100C), a load of 20 kgf / cm ² (9.8 × 10 ⁵ Pa) is applied, and 1 g of a sample is set to be extruded from a die (nozzle, diameter 1 mm, length 1 mm). Then, the temperature was increased at a heating rate of 6 ° C. per minute, and the temperature at which half of the sample flowed out from the die was determined and used as the softening point.

[Acid value]
The acid value (KOH mg / g) was determined by dissolving 1 g of a sample in 50 ml of tetrahydrofuran and titrating with a 0.1 N potassium hydroxide-ethanol solution (manufactured by Kishida Chemical Co., Ltd.) to obtain 0.1 N hydroxide required for neutralization. It calculated from the quantity of the potassium-ethanol solution. An automatic potentiometric titrator (trade name: AT-510, manufactured by Kyoto Electronics Co., Ltd.) was used for titration, and # 100-C172 (trade name: manufactured by Kyoto Electronics Industry Co., Ltd.) was used for electrodes.

[Hydroxyl value]
The hydroxyl value (KOHmg / g) is in accordance with Japanese Industrial Standard (JIS) K1557-1970, 1 g of a sample is dissolved in 50 ml of phthalic anhydride, and titrated with a 0.5N sodium hydroxide solution and required for neutralization. Calculated from the amount of 0.5N sodium hydroxide solution. An automatic potentiometric titrator (trade name: AT-510, manufactured by Kyoto Electronics Co., Ltd.) was used for titration, and # 100-C172 (trade name: manufactured by Kyoto Electronics Industry Co., Ltd.) was used for electrodes.

[Volume average particle diameter and coefficient of variation (CV value)]
The volume average particle diameter of the toner particles was calculated from the results of measurement using Coulter Multisizer III (trade name, manufactured by Coulter, Inc.). The number of measured particles was 50,000 counts, and the aperture diameter was 100 μm. The coefficient of variation (CV value) was calculated from the following formula based on the volume average particle size obtained from the measured particle size and its standard deviation.
Coefficient of variation = standard deviation / volume average particle size

(Synthesis Example 1)
[Synthesis example of polyether polyol fine particles for shell]
A 500 ml separable flask equipped with a stirrer, a thermometer, a nitrogen inlet, and a cooling tube was added to a low molecular weight bisphenol A type liquid epoxy resin (trade name: Epomic R140P, manufactured by Mitsui Chemicals, epoxy equivalent 188 g / equivalent, viscosity. (13500 mPa · s) 156.1 g, polymer bisphenol A type liquid epoxy resin (trade name: Epomic R309R, manufactured by Mitsui Chemicals, epoxy equivalent 2630 g / equivalent) 15.0 g, bisphenol A 60.3 g, benzoic acid 23.6 g , 45.0 g of phthalic anhydride adduct of bisphenol A-added propylene oxide (trade name: KB-280, Mitsui Chemicals, Inc.) and 33.3 g of xylene were charged, and the temperature was raised under a nitrogen atmosphere. 50% tetramethylammonium chloride aqueous solution (catalyst) at 120 ° C. μl was added. When the temperature was further raised and the internal temperature reached 160 ° C., the reaction was started in the solution. The mixture was stirred while maintaining an internal temperature of 160 ° C., reacted for 1 hour, 120 μl of 50% tetramethylammonium chloride aqueous solution (catalyst) was added, and xylene concentration under reduced pressure was started. Further, the pressure was reduced to 10 mmHg over about 1 hour while maintaining the temperature at 160 ° C. During the reaction, the residual amount of the epoxy group was measured every predetermined time. As a result, the epoxy equivalent showed 20000 g / equivalent or more in about 6 hours, and it was confirmed that the epoxy group substantially disappeared. At this point (7 hours after the start of the reaction), 9.1 g of acid anhydride hexahydrophthalic anhydride (trade name: Ricacid MH-700, manufactured by Shin Nippon Rika Co., Ltd.) was added, and the acid value was measured every hour. As a result, the acid value was stabilized at 8.5 KOH mg / g in about 4 hours, and thus the molten acid addition polyether polyol resin thus formed was taken out from the flask. Softening point of the obtained acid addition polyether polyol resin: 116 ° C., glass transition point: 64 ° C., acid value: 8.5 KOH mg / g, hydroxyl value: 65 KOH mg / g, number average molecular weight (Mn): 3370, weight average Molecular weight (Mw): 15260, Mw / Mn: 4.5.

  100 parts of the above polyether polyol resin was coarsely pulverized with a cutter mill (trade name: VM-16, manufactured by Orient Co., Ltd.) to prepare a coarse powder having a particle size of 500 to 800 μm. 100 parts of a coarse powder are mixed in an aqueous solution obtained by dissolving 1 part of a polymeric dispersant (trade name: John Grill 51, manufactured by Johnson Polymer Co., Ltd.) and 1 part of sodium dodecylbenzenesulfonate in 490 parts of deionized water. A coarse powder aqueous slurry was prepared. This aqueous slurry was pretreated by passing it through a nozzle having an inner diameter of 0.3 mm under a pressure of 50 MPa, and the particle size of the coarse powder in the aqueous slurry was adjusted to 100 μm or less.

  The coarse powder aqueous slurry obtained above was pressurized and heated to 150 MPa and 130 ° C., and supplied from the pressure-resistant piping to a pressure-resistant nozzle attached to the outlet of the pressure-resistant piping. The pressure-resistant nozzle is a pressure-resistant multiple nozzle having a length of 0.5 cm formed such that two liquid flow holes having a hole diameter of 0.143 mm are substantially parallel in the longitudinal direction of the nozzle. The temperature of the aqueous slurry at the nozzle inlet was 130 ° C. and the back pressure was 210 MPa. The temperature of the aqueous slurry at the nozzle outlet was 170 ° C. and the back pressure was 42 MPa. The aqueous slurry discharged from the pressure nozzle was introduced into a serpentine cooler connected to the outlet of the pressure nozzle and cooled. The temperature of the aqueous slurry at the cooler outlet was 20 ° C., and the back pressure was 1 MPa. The aqueous slurry discharged from the cooler outlet was introduced into a multistage pressure reducing device connected to the cooler outlet, and decompressed. The multistage pressure reducing device is formed by connecting five metal pipe-shaped members having different inner diameters with ring-shaped seals. The inner diameters of the five metal pipe members were changed stepwise from 0.5 mm to 1 mm. From the aqueous slurry discharged from the multistage pressure reducing device, polyether polyol resin fine particles A for shells having a particle size of 45 to 155 nm were obtained.

(Synthesis Example 2)
An acid-added polyether polyol resin was obtained in the same manner as in Synthesis Example 1 except that the reaction time was 50 minutes. This acid addition polyether polyol resin has a softening point: 115 ° C., a glass transition point: 62 ° C., an acid value: 15.0 KOH mg / g, a hydroxyl value: 53 KOH mg / g, a number average molecular weight (Mn): 3065, and a weight average molecular weight. (Mw): 4040, Mw / Mn: 4.6. Moreover, it carried out similarly to the synthesis example 1, and obtained the polyether polyol resin fine particle B for shells with a particle size of 45-121 nm.

  Synthesis Examples 3 to 9 (corresponding to the polyether polyol resin fine particles C, D, E, F, G, H, and I for shells) were also produced by the same method. The physical property values are shown in Table 1.

Example 1
[Example of core particle production]
8 parts of carbon black particles (colorant, trade name; NIPX60, manufactured by Degussa), 5 parts of ester wax particles (release agent, trade name: WEP-5, manufactured by NOF Corporation, melting point 82 ° C.), polyester (binding) Adhesive resin, softening point (Tm) 125 ° C., glass transition point (Tg) 58 ° C., 90 parts, and charge control agent (trade name: TRH, Hodogaya Chemical Co., Ltd.) 2 parts are mixed. Mixing was performed using a machine (trade name: Henschel mixer, manufactured by Mitsui Mining Co., Ltd.) to obtain a raw material mixture. The obtained raw material mixture is a temperature (Tm + 15 ° C.) that is 15 ° C. higher than the softening point (Tm) of the binder resin in a biaxial extrusion kneader (trade name: PCM30, manufactured by Ikegai Co., Ltd.). The mixture was kneaded at 140 ° C. to obtain a kneaded product. The screw of the biaxial extrusion kneader has an outer dimension D of 30 mm, a length dimension L in the rotation axis direction of 1 m, and a ratio (L / D) of the length dimension L to the outer dimension D of 33. A screw was used.

  Also, ion-exchanged water (conductivity 8 μS / cm) and styrene-acrylic acid copolymer ammonium salt (dispersant, trade name: Jonkrill 52, manufactured by Johnson Polymer Co., Ltd.) so that the solid content concentration becomes 2% by weight. And 2% aqueous solution of the dispersant was prepared.

  100 parts of the kneaded product obtained above and 400 parts of a 20% aqueous solution of a dispersing agent were placed in a metal cylindrical pressure-resistant container (high-speed rotating dispersion granulator equipped with a pressure control valve, heating means and rotor-stator stirring means. , Trade name: foamless mixer, manufactured by Miki Co., Ltd.), rotation speed of rotating rotor (outer diameter 30 mm): 10000 rpm, granulation temperature: 150 ° C., granulation pressure: 0.17 MPa for 10 minutes Granulation was performed to prepare fine particles of the kneaded material of the toner raw material.

  In the cylindrical pressure vessel, heating was stopped while maintaining the rotational speed of the rotating rotor at 10,000 rpm, and cooling was performed until the temperature of the aqueous dispersion of the dispersant containing fine particles reached 20 ° C. After cooling, the aqueous dispersion of the dispersant containing fine particles is taken out from the cylindrical pressure vessel, filtered to separate the fine particles, and dried in a vacuum dryer at a temperature of 50 ° C. for 8 hours, and the volume average particle size Core particles having a size of 5.3 μm and a coefficient of variation (CV value) of 22 were obtained.

[Manufacture of capsule toner]
An aqueous slurry is prepared by mixing 100 parts of core particles and 15 parts of the polyether polyol resin fine particles A obtained in Synthesis Example 1 in an aqueous solution in which 1 part of sodium dodecylbenzenesulfonate is dissolved in 500 parts of deionized water. did. While stirring at 2000 rpm with a homogenizer, a 0.1 wt% magnesium sulfate aqueous solution was added dropwise to this aqueous slurry little by little. Thereafter, when this mixture was stirred for 1 hour, the polyether polyol resin fine particles on the surface of the core particles were dispersed. Aggregation was observed. The aqueous slurry containing the aggregated particles was stirred at a temperature of 81 ° C. for 2 hours to form toner particles that are aggregated particles having a uniform particle size and shape in the aqueous slurry. The toner particles isolated from the aqueous slurry by filtration are washed three times with pure water (conductivity 0.5 μS / cm) and then dried by a vacuum dryer, and the capsule toner has a volume average particle diameter of 6.2 μm and a coefficient of variation of 24. Manufactured. Pure water was prepared from tap water using an ultrapure water production apparatus (trade name: Ultra Pure Water System CPW-102, manufactured by ADVANTEC). The conductivity of water was measured using a Lacom tester (trade name: EC-PHCON10, manufactured by AS ONE Corporation). 100 parts of the obtained toner is externally treated by treating 1.5 parts of silica fine particles (trade name: RX-200, manufactured by Nippon Aerosil Co., Ltd.) with a silane coupling agent using a Henschel mixer. The capsule toner of Example 1 was produced.

(Example 2)
A capsule toner of Example 2 was produced in the same manner as in Example 1 except that the polyether polyol resin fine particle B for shell of Synthesis Example 2 was used as the polyether polyol resin fine particle for shell.

(Example 3)
A capsule toner of Example 3 was produced in the same manner as in Example 1 except that the polyether polyol resin fine particle C for shell of Synthesis Example 3 was used as the polyether polyol resin fine particle for shell.

Example 4
A capsule toner of Example 4 was produced in the same manner as in Example 1 except that the polyether polyol resin fine particle D for shell of Synthesis Example 4 was used as the polyether polyol resin fine particle for shell.

(Example 5)
A capsule toner of Example 5 was produced in the same manner as in Example 1 except that the polyether polyol resin fine particles A for shells were changed to 5 parts.

(Example 6)
A capsule toner of Example 6 was produced in the same manner as in Example 1 except that the polyether polyol resin fine particles A for shells were changed to 25 parts.

(Comparative Example 1)
A capsule toner of Comparative Example 1 was produced in the same manner as in Example 1 except that the polyether polyol resin fine particles E for shell of Synthesis Example 5 were used as the polyether polyol resin fine particles for shell.

(Comparative Example 2)
A capsule toner of Comparative Example 2 was produced in the same manner as in Example 1 except that the polyether polyol resin fine particle F for shell of Synthesis Example 6 was used as the polyether polyol resin fine particle for shell.

(Comparative Example 3)
A capsule toner of Comparative Example 3 was produced in the same manner as in Example 1 except that the polyether polyol resin fine particle G for shell of Synthesis Example 7 was used as the polyether polyol resin fine particle for shell.

(Comparative Example 4)
A capsule toner of Comparative Example 4 was produced in the same manner as in Example 1 except that the polyether polyol resin fine particles H for shell of Synthesis Example 8 were used as the polyether polyol resin fine particles for shell.

(Comparative Example 5)
A capsule toner of Comparative Example 5 was produced in the same manner as in Example 1 except that the polyether polyol resin fine particle I for shell of Synthesis Example 9 was used as the polyether polyol resin fine particle for shell.

(Comparative Example 6)
Core particles were produced in the same manner as in Example 1, and this was used as the toner of Comparative Example 6.

(Comparative Example 7)
A capsule toner of Comparative Example 7 was produced in the same manner as in Example 1 except that the polyether polyol resin fine particles A for shell were changed to 0.5 part.

(Comparative Example 8)
A capsule toner of Comparative Example 8 was produced in the same manner as in Example 1 except that the polyether polyol resin fine particles A for shell were changed to 45 parts.

(Comparative Example 9)
A capsule toner of Comparative Example 9 was produced in the same manner as in Example 1 except that a methyl polymethacrylate resin was used instead of the polyether polyol resin fine particles A for shell.

  The toners obtained in Examples and Comparative Examples were evaluated for fixability and storage stability as follows.

Using the above toner and developer, evaluation was performed with an actual machine. The evaluation conditions and evaluation results are shown below. As a machine for evaluation, a digital full-color multifunction machine (manufactured by Sharp Corporation: AR-C150) was used, and the toner adhesion amount on the solid image portion on the fixing paper was 0 under normal temperature and normal humidity (20 ° C., humidity 60%). Evaluation was performed under development conditions of 0.5 mg / cm ² . For the image density, the optical density of the evaluation image was measured using a spectrocolorimetric densitometer (manufactured by Japan Planographic Printing Equipment Co., Ltd .: X-Rite 938).

[Fixability]
Using an evaluation machine (AR-C150) with the oil application mechanism of the fixing unit removed, the toner fixability was evaluated at a roll speed of 224 mm / s. Further, the determination was made based on the following criteria based on the fixing range obtained by subtracting the temperature at which the cold offset occurred from the temperature at which the hot offset occurred.
○: Good. The fixing range width is larger than 70 ° C.
Δ: No problem in actual use. The fixing range width is 50 ° C. or higher and 70 ° C. or lower.
X: Defect. Fixing range width is less than 50 ° C.

[Storage stability]
After 100 g of toner was sealed in a plastic container and allowed to stand at 50 ° C. for 48 hours, the toner was taken out and passed through a # 100 mesh sieve. The weight of the toner remaining on the sieve was measured, and the remaining amount, which is the ratio of this weight to the total toner weight, was determined and evaluated according to the following criteria. A lower numerical value indicates that the toner does not block and the storage stability is better.
○: Good. The remaining amount is less than 10%.
Δ: No problem in actual use. The remaining amount is 10% or more and less than 15%.
X: Defect. The remaining amount is 15% or more.

  The above evaluation results are shown in Table 2. In Table 2, in the column of shell, the alphabet attached after the polyether polyol resin fine particles for shell is described. As the shell, those other than the polyether polyol resin are described as “others”. The shell ratio is the weight (%) of the shell with respect to 100 parts by weight of the core particles.

  The capsule toners of Examples 1 to 6 had both low-temperature fixability and good storage stability, and were excellent in charge stability and adhesion to paper. In addition, the number of images that can be formed per unit amount is greater than that of conventional toners, and high-quality color images can be formed in which toner is fixed at high strength on a recording medium such as paper.

It is a flowchart which shows the manufacturing method of a resin particle roughly. 2 is a cross-sectional view schematically showing a configuration of a pressure-resistant nozzle 1. FIG. 1 is a top view schematically showing a configuration of a high-speed rotary dispersion granulator 11. FIG. It is a perspective view which shows typically the structure of the tracking screen 14 which is a structural member of the high-speed rotation dispersion type granulator 11. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pressure-resistant nozzle 2 Liquid flow passage 3 Collision wall 4 Arrow 11 High-speed rotation dispersion granulator 12 Cylindrical pressure-resistant container 12a Internal space 12b Outer wall 13 Rotating rotor 13a Rotating shaft 13b Stirring blades 14, 15 Following screen 16 Fixed screen 17 Liquid Flowing slit 18 arrow

Claims (6)

Including a shell layer containing a polyether polyol resin, and core particles containing polyester , which is a synthetic resin different from the polyether polyol resin, and having a core / shell type structure,
Including 100 parts by weight of the core particles, 5 parts by weight or more and 25 parts by weight or less of the shell layer,
The polyether polyol resin has a hydroxyl value of 50 KOH mg / g or more and a glass transition point of 58 ° C. or more and 64 ° C. or less, and an electrophotographic capsule toner. 2. The electrophotographic capsule toner according to claim 1, wherein the synthetic resin of a type different from the polyether polyol resin has an acid value of 5 KOH mg / g or more and 200 KOH mg / g or less. Polyether polyol resin, electrophotographic encapsulated toner according to claim 1 or 2, characterized in that an acid addition polyether polyol resin. Polyether polyol resin, a capsule toner for electrophotography according to any one of claims 1-3, wherein the number-average molecular weight of 1,000 to 10,000. The capsule toner for electrophotography according to any one of claims 1 to 4 , wherein the synthetic resin of a type different from the polyether polyol resin has a compressive strength higher than that of the polyether polyol resin. The capsule toner for electrophotography according to any one of claims 1 to 5 , wherein the glass transition point of the core particles is 5 to 30 ° C lower than the glass transition point of the shell layer.

Images