JP2012118396A - Electrophotographic toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographic toner and a production method of the toner excellent in offset resistance of the toner.SOLUTION: The electrophotographic toner comprises a binder resin containing a non-crystalline polyester, a release agent and cyclopentanone, in which the cyclopentanone is included by 5 to 150 ppm. The production method of the electrophotographic toner includes a step of mixing an aqueous dispersion of the noncrystalline polyester containing cyclopentanone with an aqueous dispersion liquid of the release agent, and aggregating particles in the aqueous dispersion liquid to obtain an aqueous dispersion liquid of aggregated particles.

Description

  The present invention relates to an electrophotographic toner used for developing a latent image formed in an electrophotographic method, an electrostatic recording method, an electrostatic printing method, and the like, and a method for producing the same.

  In Patent Document 1, a raw material for toner containing at least a binder resin, a colorant, a charge control agent, and a release agent is dissolved or dispersed in an organic solvent to obtain an oily raw material liquid and the oily raw material liquid. It includes a spray drying / granulating step of forming colored resin particles by mixing or colliding with a compressed inert gas to form a spray flow and then supplying the spray dryer with a mechanism for causing the spray flows to collide with each other. A method for producing a toner is disclosed, and cyclopentanone is exemplified as the organic solvent.

JP 2009-175632 A

The toner is desired to contain a release agent such as polyethylene wax and Fischer-Tropsch wax in order to impart release properties (offset resistance).
On the other hand, a low molecular weight, low softening point polyester exhibits excellent low-temperature fixability, but amorphous polyester and wax have low compatibility, and if the polyester has a low molecular weight, the suppression by viscosity does not work. The dispersibility of the wax also decreases. In particular, when a toner is produced by a method including a step of obtaining an aggregated particle by subjecting an aqueous dispersion of an amorphous polyester and a wax dispersion to an aggregation step, the dispersion share cannot be obtained during melt kneading. The tendency is remarkable. Therefore, even if the polyester is designed to contain a wax at the time of aggregation, the wax may come off from the toner particles when coalescing the aggregated particles.

  In contrast, the inventors of the present invention finely disperse cyclopentanone, which is highly compatible with a release agent (wax), in the toner particles, so that cyclopentanone functions as a compatibilizing agent, It has been found that there is an effect of suppressing the loss of wax at the time of agglomeration and preventing a decrease in offset resistance.

  Patent Document 1 exemplifies cyclopentanone as an organic solvent, but describes that the organic solvent is efficiently distilled off during granulation while spray drying in the process of a spray dryer. .

  An object of the present invention is to provide an electrophotographic toner excellent in offset resistance of the toner and a method for producing the same.

The present invention
[1] An electrophotographic toner comprising an amorphous polyester-containing binder resin, a release agent, and cyclopentanone, wherein the cyclopentanone content is 5 to 150 ppm, and [2] The method for producing an electrophotographic toner according to [1], wherein an aqueous dispersion of an amorphous polyester containing cyclopentanone and an aqueous dispersion of a release agent are mixed, and particles in the aqueous dispersion are mixed. The present invention relates to a method for producing an electrophotographic toner, which comprises a step of agglomerating particles to obtain an aqueous dispersion of aggregated particles.

  The toner for electrophotography of the present invention has an excellent effect of being excellent in offset resistance.

  The electrophotographic toner of the present invention contains a binder resin containing an amorphous polyester, a release agent, and cyclopentanone. The content of cyclopentanone is 5 ppm or more, preferably 10 ppm or more, more preferably 30 ppm or more, and more preferably 50 ppm or more, from the viewpoint of suppressing wax loss and improving offset resistance in the toner of the present invention. If it exceeds 150 ppm, the offset resistance decreases due to cyclopentanone. Therefore, it is 150 ppm or less, preferably 120 ppm or less, and more preferably 100 ppm or less. From these viewpoints, the content of cyclopentanone is 5 to 150 ppm, preferably 10 to 120 ppm, more preferably 30 to 100 ppm, and more preferably 50 to 100 ppm from the viewpoint of improving offset resistance in the toner of the present invention. Is more preferable. Although ppm is a fraction because it is a fraction, in the present invention, as described in the examples, the value obtained by gas chromatography is μg / g.

  Cyclopentanone may be added to the binder resin together with an additive such as a colorant during the production of the toner, and the release of the cyclopentanone into the toner is improved by improving the affinity with the release agent (wax). From the viewpoint of improving the offset resistance of the toner by improving the content of the mold agent, it is preferably contained in advance in the amorphous polyester.

Examples of the method of previously containing cyclopentanone in the amorphous polyester include the following methods (1) to (3).
(1) A method of mixing cyclopentanone together with a carboxylic acid component and an alcohol component during the production of amorphous polyester. In this method, the carboxylic acid component, the alcohol component, and the cyclopentanone may be mixed and then subjected to condensation polymerization, or the cyclopentanone may be mixed during the condensation polymerization reaction between the carboxylic acid component and the alcohol component. .

  In the case of the method (1), the amount of cyclopentanone used is a total of 100 carboxylic acid components and alcohol components from the viewpoint of adjusting the content of cyclopentanone in the toner and improving the offset resistance of the toner. 0.001-0.05 weight part is preferable with respect to a weight part, and 0.005-0.04 weight part is more preferable.

(2) A method of mixing the produced amorphous polyester and cyclopentanone. The amorphous polyester is preferably mixed with cyclopentanone at a softening point or higher.

  In the case of the method (2), the mixing amount of the amorphous polyester and the cyclopentanone is improved in the toner offset resistance by increasing the release agent content in the toner by improving the affinity with the wax. From the viewpoint of improvement, 0.0005 to 0.02 parts by weight is preferable and 0.002 to 0.018 parts by weight is more preferable with respect to 100 parts by weight of amorphous polyester.

(3) Using a carboxylic acid component containing an adipic acid compound and an alcohol component as raw material monomers for an amorphous polyester, and using an adipic acid cyclization catalyst together with an esterification catalyst to produce cyclopentanone from the adipic acid compound A method in which a condensation polymerization reaction is carried out.

  In the method (3), it is known that adipic acid is cyclized and condensed to cyclopentanone by heating at high temperature in the presence of a catalyst such as zeolite, heteropolyacid, and phosphate (special table). 2001-515876). Therefore, in the case of producing an amorphous polyester by polycondensation of an alcohol component and a carboxylic acid component containing an adipic acid compound, the reaction is preferably performed at 200 to 250 ° C. in the presence of a cyclization catalyst. At the same time that adipic acid is cyclized to cyclopentanone, the condensation reaction can proceed, and an amorphous polyester containing cyclopentanone can be obtained efficiently.

  The amount of the cyclization catalyst used is preferably 0.1 to 5 parts by weight and more preferably 0.3 to 3 parts by weight with respect to 100 parts by weight of adipic acid. The reaction temperature is preferably 200 to 250 ° C, more preferably 230 to 250 ° C, from the viewpoint of proceeding the condensation reaction and the cyclization reaction. In addition, an esterification catalyst can be used with a cyclization catalyst, and the preferable ester catalyst amount is the same as that of the below-mentioned.

  Among the methods (1) to (3), the methods (1) and (3) are preferable from the viewpoint of the compatibility of cyclopentanone with an amorphous polyester.

  The binder resin contains an amorphous polyester from the viewpoint of low-temperature fixability of the toner.

  Here, the crystallinity of a resin such as polyester is the crystallinity defined by the ratio of the softening point to the highest endothermic peak temperature measured by a differential scanning calorimeter (DSC), that is, the “softening point / the highest endothermic peak temperature”. Expressed by an index. Generally, when the crystallinity index exceeds 1.4, the resin is amorphous, and when it is less than 0.6, the crystallinity is low and there are many amorphous portions. In the present invention, “crystalline polyester” means a polyester having a crystallinity index of 0.6 to 1.4, preferably 0.9 to 1.2, more preferably 1.0 to 1.2, and “amorphous polyester” means a crystallinity index. Refers to polyesters with a value greater than 1.4 or less than 0.6.

  The “maximum endothermic peak temperature” refers to the temperature of the peak on the highest temperature side among the endothermic peaks observed under the conditions of the measurement methods described in the examples. If the maximum peak temperature is within 20 ° C of the softening point, the maximum peak temperature is the melting point of the crystalline resin (crystalline polyester), and the peak with a difference of more than 20 ° C from the softening point is amorphous polyester glass. The peak is attributed to the transition.

  The crystallinity of the resin can be adjusted by the types and ratios of the raw material monomers, production conditions (for example, reaction temperature, reaction time, cooling rate) and the like.

  In the carboxylic acid component of the amorphous polyester, examples of the dicarboxylic acid compound include oxalic acid, malonic acid, maleic acid, adipic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, sebacic acid, and azelaic acid. Aliphatic dicarboxylic acids; aromatic dicarboxylic acids such as phthalic acid, isophthalic acid and terephthalic acid; alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid; and anhydrides of these acids, alkyl (carbon number 1 to 3) esters, etc. Can be mentioned.

  When an adipic acid compound is used, from the viewpoint of hot offset resistance of the toner, 1 to 25 mol% is preferable, 2 to 20 mol% is more preferable, and 3 to 15 mol% is more preferable. Since the adipic acid compound is considered to be cyclized to cyclopentanone under a specific temperature and catalytic condition as described above, it is preferable because the cyclopentanone does not need to be mixed with the polyester.

  The carboxylic acid component preferably contains an aromatic dicarboxylic acid compound from the viewpoint of the charging rate of the toner. In the carboxylic acid component, the content of the aromatic dicarboxylic acid compound is preferably 30 to 90 mol%, more preferably 40 to 90 mol%, and still more preferably 50 to 85 from the viewpoint of low-temperature fixability and chargeability of the toner. Mol%.

  Examples of the trivalent or higher polyvalent carboxylic acid compounds include 1,2,4-benzenetricarboxylic acid (trimellitic acid), 2,5,7-naphthalenetricarboxylic acid, pyromellitic acid and other aromatic carboxylic acids, and these Derivatives such as acid anhydrides and alkyl (C1-3) esters are exemplified.

  Other carboxylic acid compounds include rosin and rosin modified with fumaric acid, maleic acid, acrylic acid and the like.

  In the present invention, the carboxylic acid component is a trivalent or higher polyvalent carboxylic acid compound, preferably a trimellitic acid compound, more preferably from the viewpoint of adjusting the molecular weight of the resin and enhancing the carrier contamination resistance and storage stability of the toner. It preferably contains trimellitic anhydride. The content of the trivalent or higher polyvalent carboxylic acid compound is preferably 0.1 to 30 mol%, more preferably 1 to 25 mol%, and still more preferably 5 to 25 mol% in the carboxylic acid component.

  The alcohol component of the amorphous polyester (a) is a polyoxypropylene adduct of 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis, from the viewpoint of low-temperature fixability and hot offset resistance of the toner. Aromatic diols such as alkylene oxide adducts of bisphenol A represented by the following formula (I) including polyoxyethylene adducts of (4-hydroxyphenyl) propane are preferred, and 70 to 100 mol% in the alcohol component Preferably, 80-100 mol% is more preferable, and 90-100 mol% is further more preferable.

(In the formula, R ¹ O and OR ¹ are oxyalkylene groups, R ¹ is an ethylene and / or propylene group, x and y indicate the number of added moles of alkylene oxide, and each is a positive number; The average value of the sum of y and y is preferably 1 to 16, more preferably 1 to 8, and even more preferably 1.5 to 4)

  Polyoxypropylene adduct of 2,2-bis (4-hydroxyphenyl) propane and polyoxyethylene adduct of 2,2-bis (4-hydroxyphenyl) propane should be used together from the viewpoint of toner offset resistance. The molar ratio (polyoxypropylene adduct of 2,2-bis (4-hydroxyphenyl) propane / polyoxyethylene adduct of 2,2-bis (4-hydroxyphenyl) propane) is 50/50 to 90/10 is preferable, and 60/40 to 90/10 is more preferable.

  Examples of other alcohol components include aliphatic diols having 2 to 12 carbon atoms; trivalent or higher alcohols such as glycerin, pentaerythritol, and trimethylolpropane.

  Examples of the aliphatic diol having 2 to 12 carbon atoms include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,2-pentanediol, 1,3-pentanediol, 1,4-pentanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1 , 8-octanediol, neopentyl glycol, 2,3-pentanediol, 2,4-pentanediol and the like. Among these, at least one selected from the group consisting of ethylene glycol, 1,2-propanediol, 1,3-propanediol, 2,3-butanediol, and neopentylglycol from the viewpoint of low-temperature fixability of the toner. Is preferred.

  The content of the aliphatic diol having 2 to 12 carbon atoms is preferably 0 to 70 mol%, more preferably 0 to 50 mol%, and more preferably 0 to 30 mol% in the alcohol component from the viewpoint of low-temperature fixability of the toner. Further preferred.

  A monovalent alcohol may be appropriately contained in the alcohol component, and a monovalent carboxylic acid compound may be appropriately contained in the carboxylic acid component from the viewpoint of adjusting the molecular weight of the resin.

  The molar ratio of the alcohol component and the carboxylic acid component (carboxylic acid component / alcohol component), which is the raw material monomer of the amorphous polyester, is preferably 0.50 to 1.10, preferably 0.55 to 0.90, from the viewpoint of fixing properties. More preferably, it is 0.60 to 0.80.

  In the present invention, the above amorphous polyester includes not only polyester but also modified resins thereof.

  Examples of the modified resin include urethane-modified polyester in which polyester is modified with a urethane bond, epoxy-modified polyester in which polyester is modified with an epoxy bond, and a hybrid resin having two or more kinds of resin components including a polyester component. .

  The softening point of the amorphous polyester is preferably 68 to 160 ° C., more preferably 68 to 120 ° C., further preferably 68 to 100 ° C., and still more preferably 68 to 88 ° C., from the viewpoint of low-temperature fixability of the toner. is there.

  In the present invention, it is preferable to use an amorphous polyester (a) having a low softening point and an amorphous polyester (b) having a high softening point from the viewpoint of low-temperature fixability and hot offset property of the toner.

  The softening point of the low-softening point amorphous polyester (a) is preferably 60 to 100 ° C, more preferably 60 to 90 ° C, and further preferably 70 to 85 ° C. The softening point of the amorphous polyester (b) having a high softening point is more than 100 ° C, preferably 160 ° C, more preferably 120 to 160 ° C, more preferably 125 to 155 ° C, more preferably 110 to 140 ° C. 115 ° C to 135 ° C. The difference in softening point between the low softening point amorphous polyester and the high softening point amorphous polyester is preferably 10 to 90 ° C, more preferably 20 to 80 ° C. Weight ratio of amorphous polyester (a) having a low softening point and amorphous polyester (b) having a high softening point (amorphous polyester (a) having a low softening point / amorphous polyester having a high softening point (b) ) Is preferably 90/10 to 60/40, more preferably 85/15 to 70/30.

  The toner of the present invention is separated from the binder resin containing the amorphous polyester (a) having a low softening point from the viewpoint of enhancing the compatibility between the release agent and cyclopentanone and improving the offset resistance of the toner. A toner containing a mold agent and cyclopentanone is preferable. Hereinafter, when it is simply described as amorphous polyester, it means both amorphous polyesters (a) and (b).

  The number average molecular weight of the amorphous polyester (a) is preferably 1000 to 2500, more preferably 1100 to 2000, and further preferably 1200 to 1800, from the viewpoint of low-temperature fixability of the toner. The weight average molecular weight is preferably 3000 to 7000, more preferably 3500 to 6000, and further preferably 3500 to 5500, from the viewpoint of low-temperature fixability of the toner.

  The number average molecular weight of the amorphous polyester (b) is preferably 2600 to 6000, more preferably 2700 to 5000, and further preferably 2800 to 4000 from the viewpoint of offset resistance of the toner. The weight average molecular weight is preferably 100,000 to 2,000,000, and more preferably 200,000 to 1,500,000 from the viewpoint of offset resistance of the toner. The number average molecular weight and the weight average molecular weight of the amorphous polyester are both values obtained by measuring the tetrahydrofuran-soluble content described in the examples.

  The acid value of the amorphous polyester is preferably 5 to 50 mgKOH / g, more preferably 10 to 40 mgKOH / g, and further preferably 15 to 35 mgKOH / g, from the viewpoint of low-temperature fixability of the toner. The hydroxyl value is preferably 20 to 100 mgKOH / g, more preferably 30 to 80 mgKOH / g, and further preferably 35 to 60 mgKOH / g, from the viewpoint of low-temperature fixability of the toner.

  The glass transition point of the amorphous polyester (a) is preferably 35 to 45 ° C., more preferably 37 to 43 ° C., from the viewpoint of low-temperature fixability of the toner. The glass transition point of the amorphous polyester (b) is preferably 50 to 80 ° C., more preferably 55 to 70 ° C., from the viewpoint of offset resistance of the toner.

  The softening point, number average molecular weight, weight average molecular weight, acid value, hydroxyl value, and glass transition point can be adjusted by adjusting the raw material monomer composition, polymerization initiator, molecular weight, catalyst amount, etc., or by selecting reaction conditions. .

  In the production of amorphous polyester, the polycondensation reaction between an alcohol component and a carboxylic acid component can be performed in an inert gas atmosphere in the presence of an esterification catalyst, such as a tin compound or a titanium compound, which will be described later. The final ultimate temperature after temperature rise in the production of amorphous polyester is preferably 180 to 250 ° C, more preferably 190 to 250 ° C.

  As a tin compound used as an esterification catalyst, for example, dibutyltin oxide is known. In the present invention, from the viewpoint of improving dispersibility in polyester, tin having no Sn—C bond is used. Compound (II) is preferred.

  Examples of the tin (II) compound having no Sn—C bond include a tin (II) compound having a Sn—O bond, a tin (II) compound having a Sn—X (X represents a halogen atom) bond, and the like. Preferably, a tin (II) compound having a Sn—O bond is more preferable.

Examples of tin (II) compounds having Sn-O bonds include tin (II) oxalate, tin (II) acetate, tin (II) octoate, tin (II) 2-ethylhexanoate, and tin (II) laurate. , Tin (II) carboxylate having a carboxylic acid group having 2 to 28 carbon atoms such as tin (II) stearate, tin (II) oleate; octyloxy tin (II), lauroxy tin (II), stearoxy tin (II) ), Alkoxytin (II) having an alkoxy group having 2 to 28 carbon atoms such as oleyloxytin (II); tin (II) oxide; tin (II) sulfate, Sn—X (X represents a halogen atom) Examples of the tin (II) compound having a bond include tin (II) halides such as tin (II) chloride and tin (II) bromide. Among these, from the viewpoint of catalytic ability, (R ² COO) ₂ Sn (wherein R ² represents an alkyl or alkenyl group having 5 to 19 carbon atoms), fatty acid tin (II), (R ³ O) ₂ Sn (where R ³ is carbon 6 ~ 20 alkyl or alkenyl groups Alkoxy tin (II) and tin oxide represented by SnO (II) is preferably represented by the be), (R ² COO), more preferably the fatty acid tin represented by ₂ Sn (II) and tin oxide (II) Further preferred are tin (II) octoate, tin (II) 2-ethylhexanoate, tin (II) stearate and tin (II) oxide.

  As the titanium compound, a titanium compound having a Ti-O bond is preferable, and a compound having an alkoxy group having 1 to 28 carbon atoms, an alkenyloxy group having 2 to 28 carbon atoms, or an acyloxy group having 1 to 28 carbon atoms in total. More preferred.

Specific examples of titanium compounds include titanium diisopropylate bistriethanolamate [Ti (C ₆ H ₁₄ O ₃ N) ₂ (C ₃ H ₇ O) ₂ ], titanium diisopropylate bisdiethanolamate [Ti (C ₄ H ₁₀ O ₂ N) ₂ (C ₃ H ₇ O) ₂ ], titanium dipentylate bistriethanolamate [Ti (C ₆ H ₁₄ O ₃ N) ₂ (C ₅ H ₁₁ O) ₂ ], titanium diety rate bis triethanolaminate _{[Ti (C 6 H 14 O 3} N) 2 (C 2 H 5 O) 2 ], titanium dihydroxy octylate bis triethanolaminate _{[Ti (C 6 H 14 O 3} N) 2 (OHC 8 H ₁₆ O) ₂ ], titanium distearate bistriethanolamate [Ti (C ₆ H ₁₄ O ₃ N) ₂ (C ₁₈ H ₃₇ O) ₂ ], titanium triisopropylate triethanolamate [Ti (C ₆ H ₁₄ O ₃ N) (C ₃ H ₇ O) ₃ ], titanium monopropylate tris (triethanolaminate) [Ti (C ₆ H ₁₄ O ₃ N) ₃ (C ₃ H ₇ O)] and the like, among these, titanium diisopropylate bistri Ethanolaminate, titanium diisopropylate bisdiethanolamate and titanium dipentylate bistriethanolamate are preferred, and these are also available as commercial products of Matsumoto Trading Co., Ltd., for example.

Specific examples of other preferable titanium compounds include tetra-n-butyl titanate [Ti (C ₄ H ₉ O) ₄ ], tetrapropyl titanate [Ti (C ₃ H ₇ O) ₄ ], tetrastearyl titanate [Ti ( C ₁₈ H ₃₇ O) ₄ ], tetramyristyl titanate [Ti (C ₁₄ H ₂₉ O) ₄ ], tetraoctyl titanate [Ti (C ₈ H ₁₇ O) ₄ ], dioctyl dihydroxyoctyl titanate [Ti (C ₈ H ₁₇ O) ₂ (OHC ₈ H ₁₆ O) ₂ ], dimyristyl dioctyl titanate [Ti (C ₁₄ H ₂₉ O) ₂ (C ₈ H ₁₇ O) ₂ ] and the like. Among these, tetrastearyl titanate, tetra Myristyl titanate, tetraoctyl titanate and dioctyl dihydroxy octyl titanate are preferred. These can be obtained, for example, by reacting a titanium halide with a corresponding alcohol, or can be obtained as a commercial product such as Nisso.

  The said tin (II) compound and titanium compound can be used 1 type or in combination of 2 or more types.

  The amount of the esterification catalyst used is preferably 0.01 to 2.0 parts by weight, more preferably 0.1 to 1.5 parts by weight, and still more preferably 0.2 to 1.0 parts by weight with respect to 100 parts by weight of the total amount of the alcohol component and the carboxylic acid component.

  In the present invention, it is preferable from the viewpoint of toner durability that a pyrogallol compound having a benzene ring in which hydrogen atoms bonded to three adjacent carbon atoms are substituted with a hydroxyl group is used as a co-catalyst together with an esterification catalyst.

  Examples of pyrogallol compounds include pyrogallol, gallic acid, gallic acid esters, 2,3,4-trihydroxybenzophenone, benzophenone derivatives such as 2,2 ', 3,4-tetrahydroxybenzophenone, epigallocatechin, epigallocatechin gallate, etc. Catechin derivatives and the like.

  The weight ratio of the pyrogallol compound to the esterification catalyst (pyrogallol compound / esterification catalyst) is preferably from 0.01 to 0.5, more preferably from 0.03 to 0.3, and even more preferably from 0.05 to 0.2, from the viewpoint of storage stability of the toner.

  The binder resin of the toner of the present invention preferably further contains a crystalline polyester.

  The alcohol component which is a raw material monomer of the crystalline polyester preferably contains an aliphatic diol having 6 to 12 carbon atoms from the viewpoint of enhancing the crystallinity of the polyester.

  Examples of the aliphatic diol having 6 to 12 carbon atoms in the present invention include 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, Examples include 1,11-undecanediol, 1,12-dodecanediol, neopentyl glycol, and 1,4-butenediol. Among these, from the viewpoint of low-temperature fixability of the toner, an aliphatic diol having 6 to 12 carbon atoms is preferable, an aliphatic diol having 6 to 8 carbon atoms is more preferable, and from the viewpoint of crystallinity, An α, ω-linear alkanediol having 6 to 12 carbon atoms is preferable, an α, ω-linear alkanediol having 6 to 8 carbon atoms is more preferable, and 1,6 hexanediol is more preferable.

  The content of the aliphatic diol having 6 to 12 carbon atoms is 70 to 100 mol%, preferably 80 to 100 mol%, more preferably in the alcohol component from the viewpoint of further improving the crystallinity of the crystalline polyester. 90 to 100 mol%. The content of one kind of C6-12 α, ω-linear alkanediol in the alcohol component is preferably 70 mol% or more, more preferably 80 to 100 mol%, still more preferably 90 to 100 mol%. The content of 1,6-hexanediol is preferably 70 mol% or more, more preferably 80 to 100 mol%, and still more preferably 90 to 100 mol% in the alcohol component.

  Examples of alcohol components other than aliphatic diols having 6 to 12 carbon atoms include carbon numbers such as ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, and 1,5-pentanediol. Includes aliphatic diols other than 6-12, polyoxypropylene adducts of 2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene adducts of 2,2-bis (4-hydroxyphenyl) propane, etc. Examples include aromatic diols such as alkylene oxide adducts of bisphenol A represented by the following formula (I); trivalent or higher alcohols such as glycerin, pentaerythritol, and trimethylolpropane.

(In the formula, R ¹ O and OR ¹ are oxyalkylene groups, R ¹ is an ethylene and / or propylene group, x and y indicate the number of added moles of alkylene oxide, and each is a positive number; The average value of the sum of y and y is preferably 1 to 16, more preferably 1 to 8, and even more preferably 1.5 to 4)

  The carboxylic acid component of the crystalline polyester preferably contains at least an aliphatic dicarboxylic acid compound having 8 to 12 carbon atoms from the viewpoint of low-temperature fixability of the toner.

  Examples of the aliphatic dicarboxylic acid compound having 8 to 12 carbon atoms include suberic acid, azelaic acid, sebacic acid, 1,10-decanedicarboxylic acid and the like. Among these, from the viewpoint of low-temperature fixability of the toner, an aliphatic dicarboxylic acid compound having 10 to 12 carbon atoms is preferable, and sebacic acid is more preferable.

  The content of the aliphatic dicarboxylic acid compound having 8 to 12 carbon atoms is preferably 70 to 100 mol%, more preferably 90 to 100 mol%, still more preferably 100 mol% in the carboxylic acid component. The content of sebacic acid is preferably 70 to 100 mol%, more preferably 90 to 100 mol%, and still more preferably 100 mol% in the carboxylic acid component.

  Examples of the carboxylic acid component other than the aliphatic dicarboxylic acid compound having 8 to 12 carbon atoms include an aromatic dicarboxylic acid compound, an aliphatic dicarboxylic acid compound having 2 to 7 carbon atoms, and an aromatic polycarboxylic acid compound having 3 or more valences. Although it is mentioned, it is not particularly limited to these.

  Preferred examples of the aromatic dicarboxylic acid compound include aromatic dicarboxylic acids such as phthalic acid, isophthalic acid and terephthalic acid, anhydrides of these acids, and alkyl (C1 to C3) esters thereof.

  Examples of the aliphatic dicarboxylic acid compound having 2 to 7 carbon atoms include oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, adipic acid and the like; anhydrides of these acids and the like And alkyl (carbon number 1 to 3) esters of these acids.

  Examples of the trivalent or higher polyvalent carboxylic acid compounds include 1,2,4-benzenetricarboxylic acid (trimellitic acid), 2,5,7-naphthalenetricarboxylic acid, pyromellitic acid and other aromatic carboxylic acids, and these Derivatives such as acid anhydrides and alkyl (C1-3) esters are exemplified.

  A monovalent alcohol may be appropriately contained in the alcohol component, and a monovalent carboxylic acid compound may be appropriately contained in the carboxylic acid component from the viewpoint of adjusting the molecular weight of the resin.

  The softening point of the crystalline polyester is preferably 50 to 120 ° C., more preferably 55 to 100 ° C., and further preferably 60 to 80 ° C. from the viewpoint of low-temperature fixability of the toner.

  The melting point of the crystalline polyester is preferably 50 to 120 ° C., more preferably 55 to 100 ° C., and further preferably 60 to 80 ° C. from the viewpoint of low-temperature fixability of the toner.

  The number average molecular weight of the crystalline polyester is preferably 1000 or more, more preferably 1500 or more, from the viewpoint of low-temperature fixability of the toner. However, considering the productivity of the crystalline polyester, the number average molecular weight is preferably 6000 or less, more preferably 5000 or less, and further preferably 4500 or less. From the above viewpoint, the number average molecular weight of the crystalline polyester is preferably 1000 to 6000, more preferably 1000 to 5000, and further preferably 1500 to 4500.

  Further, from the same viewpoint as the number average molecular weight, the weight average molecular weight is preferably 3,000 or more, more preferably 5,000 or more, further preferably 8,000 or more, preferably 100,000 or less, more preferably 50,000 or less, and further preferably 30,000. Below, more preferably 20,000 or less. In view of the above, the weight average molecular weight of the crystalline polyester is preferably 3,000 to 100,000, more preferably 5,000 to 50,000, further preferably 5,000 to 30,000, and still more preferably 8,000 to 20,000.

  In the present invention, the number average molecular weight and the weight average molecular weight of the crystalline polyester are both values obtained by measuring the chloroform-soluble content described in the Examples. The number average molecular weight and the weight average molecular weight can be increased by increasing the reaction temperature of polycondensation, increasing the amount of catalyst, using a cocatalyst together, or lengthening the reaction time.

  From the viewpoint of low-temperature fixability of the toner, the molar ratio of the alcohol component, which is a raw material monomer of the crystalline polyester, to the carboxylic acid component (carboxylic acid component / alcohol component) is preferably 1.03 to 1.20, more preferably 1.03 to 1.15, more preferably 1.04 to 1.12 and even more preferably 1.05 to 1.10.

  Also in the production of the crystalline polyester, the condensation polymerization reaction between the alcohol component and the carboxylic acid component can be performed in an inert gas atmosphere in the presence of an esterification catalyst, such as a tin compound or a titanium compound, which will be described later. . The co-catalyst using the esterification catalyst and pyrogallol compound can be used in the same manner as the amorphous polyester.

  The temperature condition in the production of the crystalline polyester is preferably 130 to 250 ° C, and the final temperature after the temperature rise is preferably 180 to 250 ° C, more preferably 190 to 230 ° C.

  In the production of crystalline polyester, from the viewpoint of low-temperature fixability of the toner, the temperature is preferably 130 to 160 ° C., more preferably 130 to 160 ° C., when the theoretical reaction water amount is discharged and the reaction rate is 100%. The polycondensation reaction is preferably carried out until the reaction rate of the polycondensation reaction determined from the discharged reaction water amount is preferably 40% or more, more preferably 50% or more, and even more preferably 60% or more.

  Considering a relatively low temperature of 130 to 160 ° C., the reaction rate is preferably 80% or less, preferably 40 to 80%, more preferably 50 to 80%, and still more preferably 60 to 80%. The polycondensation reaction is preferably performed within the range.

  In the binder resin of the present invention, the weight ratio of the crystalline polyester to the amorphous polyester (amorphous polyester / crystalline polyester) is 95/5 to 50/50 from the viewpoint of improving the low-temperature fixability of the toner. Preferably, 95/5 to 60/40 is more preferable, and 93/7 to 70/30 is more preferable.

  In the present invention, known binder resins other than crystalline polyesters and amorphous polyesters, for example, vinyl resins such as styrene-acrylic resins, epoxy resins, polycarbonates, polyurethanes, etc., as long as the effects of the present invention are not impaired. Although other resins may be used in combination, the total content of the crystalline polyester and the amorphous polyester is preferably 70% by weight or more, more preferably 80% by weight or more, and 90% by weight in the binder resin. % Or more is more preferable, and it is further more preferable that it is substantially 100 weight%.

  The toner of the present invention contains a release agent (wax) from the viewpoint of offset resistance.

  As release agents, low molecular weight polyolefins such as polyethylene, polypropylene and polybutene; silicones having a softening point upon heating; fatty acid amides such as oleic acid amide, erucic acid amide, ricinoleic acid amide, and stearic acid amide; Plant waxes such as uba wax, rice wax, candelilla wax, tree wax and jojoba oil; animal waxes such as beeswax; minerals such as montan wax, paraffin wax, ozokerite, ceresin, microcrystalline wax, and Fischer-Tropsch wax Examples include petroleum wax. Among these, one or more selected from montan wax, paraffin wax, ozokerite, ceresin, microcrystalline wax, and Fischer-Tropsch wax from the viewpoint of good compatibility with cyclopentanone and improving offset resistance of the toner. Mineral and petroleum waxes are preferred. These mold release agents can be used alone or in combination of two or more.

  The melting point of the release agent is preferably 60 to 140 ° C., and more preferably 60 to 100 ° C., from the viewpoints of low-temperature fixability, chargeability, environmental stability and heat-resistant storage stability of the toner.

  The content of the release agent is preferably 1 to 20 parts by weight with respect to 100 parts by weight of amorphous polyester, from the viewpoint of low-temperature fixability, chargeability, environmental stability and heat-resistant storage stability of the toner, and 2 to 15 Part by weight is more preferable, and 3 to 13 parts by weight is further preferable.

  The toner of the present invention further includes a colorant, a charge control agent, a charge control resin, magnetic powder, a fluidity improver, a conductivity modifier, an extender pigment, a reinforcing filler such as a fibrous substance, an antioxidant, and an aging agent. Additives such as an inhibitor and a cleaning property improver may be appropriately contained.

  There is no restriction | limiting in particular as a coloring agent, A well-known coloring agent is mentioned, According to the objective, it can select suitably. Specifically, carbon black, inorganic composite oxide, chrome yellow, hansa yellow, benzidine yellow, selenium yellow, quinoline yellow, permanent orange GTR, pyrazolone orange, vulcan orange, watch young red, permanent red, brilliantamine 3B, Brilliantamine 6B, DuPont Oil Red, Pyrazolone Red, Resol Red, Rhodamine B Lake, Lake Red C, Bengal, Aniline Blue, Ultramarine Blue, Calco Oil Blue, Methylene Blue Chloride, Phthalocyanine Blue, Phthalocyanine Green, Malachite Green Oxalate, etc. Various pigments: acridine, xanthene, azo, benzoquinone, azine, anthraquinone, indico, Indigo dyes, phthalocyanine, aniline black, polymethine, triphenylmethane dyes, diphenylmethane dyes, thiazine, and include various dyes of thiazole, and the like. These can be used alone or in combination of two or more. The content of the colorant is preferably 0.1 to 20 parts by weight and more preferably 1 to 10 parts by weight with respect to 100 parts by weight of the binder resin.

  The charge control agent is not particularly limited, and may contain either a positively chargeable charge control agent or a negatively chargeable charge control agent.

  Examples of positively chargeable charge control agents include nigrosine dyes such as “Nigrosine Base EX”, “Oil Black BS”, “Oil Black SO”, “Bontron N-01”, “Bontron N-07”, “Bontron N-09” ”,“ Bontron N-11 ”(manufactured by Orient Chemical Co., Ltd.), etc .; triphenylmethane dyes containing tertiary amines as side chains, quaternary ammonium salt compounds such as“ Bontron P-51 ”(Orient Chemical) Manufactured by Kogyo Co., Ltd.), cetyltrimethylammonium bromide, “COPY CHARGE PX VP435” (manufactured by Hoechst), etc .; polyamine resin such as “AFP-B” (manufactured by Orient Chemical Co., Ltd.), etc .; , “PLZ-8001” (manufactured by Shikoku Kasei Co., Ltd.) and the like.

  In addition, as a negatively chargeable charge control agent, metal-containing azo dyes such as “Varifirst Black 3804”, “Bontron S-31” (above, manufactured by Orient Chemical Industries), “T-77” (Hodogaya Chemical) Manufactured by Kogyo Co., Ltd.), Bontron S-32, Bontron S-34, Bontron S-36 (above, Orient Chemical Co., Ltd.), Eisenspiron Black TRH (Hodogaya Chemical Co., Ltd.) A metal compound of a benzylic acid compound, such as “LR-147”, “LR-297” (manufactured by Nippon Carlit Co., Ltd.); a metal compound of a salicylic acid compound, such as “Bontron E-81”, “Bontron E- 84, “Bontron E-88”, “E-304” (manufactured by Orient Chemical Co., Ltd.), “TN-105” (manufactured by Hodogaya Chemical Co., Ltd.); copper phthalocyanine dye; quaternary ammonium salt such as “ COPY CHARGE NX VP434 "(Hoechst), nitroimidazole derivative; organometallic compound , For example, "TN105" (commercially available from Hodogaya Chemical Co., Ltd.), and the like.

  The content of the charge control agent is preferably 0.01 to 10 parts by weight, more preferably 0.01 to 5 parts by weight, and more preferably 0.3 to 3 parts by weight with respect to 100 parts by weight of the binder resin, from the viewpoint of the charge rising property of the toner. More preferably, 0.5 to 3 parts by weight is even more preferable, and 1 to 2 parts by weight is even more preferable.

  The toner of the present invention may be a toner obtained by any conventionally known method such as a melt-kneading method, an emulsion phase inversion method, or a polymerization method, but does not include a step of melt-kneading the toner raw material. The effect of the present invention is more remarkably exhibited in a toner obtained by a method in which the dispersibility of the mold is easily lowered. From such a viewpoint, the toner of the present invention is obtained by a method including a step of obtaining aggregated particles containing a binder resin and a release agent by mixing an aqueous dispersion of the binder resin and an aqueous dispersion of a release agent. It is preferable to use a toner.

  In the toner production method of the present invention, from the viewpoint of offset resistance, an aqueous dispersion of cyclopentanone and amorphous polyester and an aqueous dispersion of a release agent are mixed to aggregate particles in the aqueous dispersion. From the viewpoint of offset resistance by improving the content of the release agent in the toner, and an aqueous dispersion of an amorphous polyester containing cyclopentanone and an aqueous release agent A production method including a step of mixing the dispersion liquid and aggregating particles in the aqueous dispersion liquid is more preferable. The agglomerated particles obtained in the aggregating step preferably further include a step of coalescence in the coalescing step, and the coalesced particles obtained in the coalescing step can be used as toner particles.

  The content of cyclopentanone in the amorphous polyester is 5 to 200 ppm from the viewpoint of improving the offset resistance of the toner by improving the content of the release agent in the toner by improving the affinity with the wax. Is preferable, and 20 to 180 ppm is more preferable.

  As described above, the amorphous polyester (a) containing cyclopentanone includes (1) a method of adding cyclopentanone during the production of the amorphous polyester (a), and (2) the amorphous polyester (a) and It is preferably obtained by a method of mixing with cyclopentanone and (3) a method of cyclizing the adipic acid compound used as a raw material monomer to cyclopentanone.

The toner of the present invention is preferably composed of core-shell particles composed of a core part and a shell part from the viewpoint of suppressing exposure of the release agent to the surface. The release agent is preferably contained in the core part of the core-shell particle from the viewpoint of toner chargeability, environmental stability, and heat-resistant storage stability. The core part contains an amorphous polyester, a release agent, and cyclopentanone. Including core-shell particles is preferred. Furthermore, from the viewpoint of improving the resistance to offset by suppressing wax loss, the core portion contains the amorphous polyester (a) having a low softening point, a release agent and cyclopentanone, and the shell portion has a high softening point. Core-shell particles containing amorphous polyester (b) are preferable, and examples of a suitable method for producing a toner having such core-shell particles include methods including the following steps 1 to 4.
Step 1: An aqueous dispersion of an amorphous polyester (a) containing cyclopentanone and an aqueous dispersion of an aqueous dispersion of a release agent are mixed to agglomerate particles in the aqueous dispersion, thereby aggregating particles. Step 2 for obtaining an aqueous dispersion of A Step 2: Step for obtaining an aqueous dispersion of amorphous polyester (b) Step 3: An aqueous dispersion of aggregated particles A obtained by Step 1 and the amorphous obtained by Step 2 Step 4: Aggregating the aggregated particles B obtained in Step 3 to obtain an aqueous dispersion of the aggregated particles B by mixing the aqueous polyester (b) aqueous dispersion and aggregating the particles in the aqueous dispersion Process

  The content of cyclopentanone in the amorphous polyester (a) is the same as the content of cyclopentanone in the amorphous polyester.

When the amorphous polyester (a) does not contain cyclopentanone, instead of step 1,
Step 1 ': An aqueous dispersion of cyclopentanone and amorphous polyester (a) and an aqueous dispersion of a release agent are mixed, and particles in the aqueous dispersion are agglomerated to obtain an aqueous dispersion of aggregated particles A. It may be a step of obtaining a liquid.

  In step 1 and step 1 ′, the aqueous dispersion of the amorphous polyester (a) and the aqueous dispersion of the release agent are mixed, and the particles in the aqueous dispersion are agglomerated to obtain an aqueous dispersion of the aggregated particles A. This is a step of obtaining a liquid.

  In the case where crystalline polyester is used, in Step 1, an aqueous dispersion of crystalline polyester can be used for mixing.

  When the crystalline polyester is used, the weight ratio of the crystalline polyester and the amorphous polyester (a) (crystalline polyester / amorphous polyester (a)) determines the low-temperature fixability, chargeability, environmental stability and heat resistance of the toner. From the viewpoint of preservability, 5/95 to 40/60 is preferable, 6/94 to 30/70 is more preferable, and 7/93 to 25/75 is further preferable.

  In the present specification, the “aqueous dispersion” may contain a solvent such as an organic solvent, but water is preferably 50% by weight or more, preferably 70% by weight or more, more preferably 90% by weight or more. More preferably, the dispersion medium is an aqueous medium containing 99% by weight or more. Further, hereinafter, when simply described as “resin”, it refers to both crystalline polyester and amorphous polyester.

  The aqueous dispersion of the amorphous polyester (a) is prepared by mixing the amorphous polyester (a), an organic solvent and water, and, if necessary, a neutralizing agent and a surfactant, stirring, and then organically by distillation or the like. It is obtained by removing the solvent. Preferably, the amorphous polyester (a) and, if necessary, a surfactant are dissolved in an organic solvent, and then water, and if necessary, a neutralizing agent, a surfactant and the like are mixed. In addition, when stirring a mixture, arbitrary mixing stirring apparatuses, such as an anchor wing | blade, can be used.

  Examples of the organic solvent include alcohol solvents such as ethanol, isopropanol and isobutanol; ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone and diethyl ketone; ether solvents such as dibutyl ether, tetrahydrofuran and dioxane; It is done. Among these, ethyl acetate and methyl ethyl ketone are preferable from the viewpoint of dispersibility of the crystalline polyester.

  Examples of the neutralizing agent include alkali metals such as lithium hydroxide, sodium hydroxide, and potassium hydroxide; organic bases such as ammonia, trimethylamine, ethylamine, diethylamine, triethylamine, triethanolamine, and tributylamine.

  The amount of the organic solvent mixed with the amorphous polyester (a) is preferably 100 to 1000 parts by weight with respect to 100 parts by weight of the amorphous polyester (a). The amount of water mixed with the amorphous polyester (a) is preferably 100 to 1000 parts by weight with respect to 100 parts by weight of the organic solvent.

  30-90 degreeC is preferable and the temperature at the time of mixing an amorphous polyester (a) and an organic solvent has more preferable 30-60 degreeC.

  The volume median particle size of the amorphous polyester (a) in the aqueous dispersion is preferably 50 to 1000 nm, more preferably 50 to 500 nm, still more preferably 50 to 300 nm, and more preferably 80 to 200 nm, from the viewpoint of uniform aggregation. Is even more preferable. The volume-median particle size can be measured by a laser diffraction type particle size measuring device described later.

  The aqueous dispersion of crystalline polyester can be produced in the same manner as the aqueous dispersion of amorphous polyester (a), and the preferred range is also the same.

  The amount of the release agent contained in the aqueous dispersion of the release agent used for mixing with the aqueous dispersion of the amorphous polyester (a) is the non-existence contained in the aqueous dispersion from the viewpoint of dispersibility in the resin. The amount is preferably 1 to 20 parts by weight, more preferably 2 to 15 parts by weight, and still more preferably 3 to 12 parts by weight with respect to 100 parts by weight of the crystalline polyester (a).

  In addition, additives such as colorants, charge control agents, conductivity modifiers, extender pigments, fibrous fillers, reinforcing fillers, antioxidants, anti-aging agents, etc. can be used when preparing aqueous dispersions of resins. It may be added to the amorphous polyester (a) or the crystalline polyester in advance, or an aqueous dispersion of each additive may be separately prepared and used for mixing with the aqueous dispersion of the amorphous polyester (a). Good.

  In the flocculation step, the solid content concentration in the system is preferably 5 to 50% by weight, more preferably 5 to 30% by weight, and even more preferably 5 to 20% by weight in order to cause uniform flocculation.

  The temperature during the aggregation step is preferably 65 ° C. or less, more preferably 55 ° C. or less, from the viewpoint of uniformly dispersing the particles in the mixed aqueous dispersion, and the fluidity of the medium and the aqueous dispersion of the resin From the viewpoint of the production energy of the liquid, the dispersion treatment is preferably performed at a temperature higher than 0 ° C., more preferably 10 ° C. or higher. From these viewpoints, the particles in the aqueous dispersion are agglomerated by an ordinary method such as stirring at a temperature of preferably about 0 to 65 ° C., more preferably about 10 to 55 ° C. A uniformly dispersed aqueous dispersion can be prepared.

  In the aggregation process, an aggregating agent can be added in order to effectively perform aggregation. As the flocculant, a quaternary salt cationic surfactant, polyethyleneimine, and the like are used in the organic system, and an inorganic metal salt, an inorganic ammonium salt, a divalent or higher metal complex, and the like are used in the inorganic system.

  Examples of the inorganic metal salt include metal salts such as sodium sulfate, sodium chloride, calcium chloride, calcium nitrate, barium chloride, magnesium chloride, zinc chloride, aluminum chloride, and aluminum sulfate; polyaluminum chloride, polyaluminum hydroxide, and Examples thereof include inorganic metal salt polymers such as calcium polysulfide. Examples of the inorganic ammonium salt include ammonium sulfate, ammonium chloride, and ammonium nitrate.

  The amount of the flocculant added is preferably 60 parts by weight or less, more preferably 55 parts by weight or less, and even more preferably 50 parts by weight or less with respect to 100 parts by weight of the binder resin from the viewpoint of environmental resistance characteristics of the toner.

  The flocculant is preferably added after being dissolved in an aqueous medium, and it is preferable that the flocculant is sufficiently stirred at the time of addition of the flocculant and after completion of the addition.

  The volume median particle size of the aggregated particles A obtained in step 1 is preferably 1 to 10 μm, more preferably 2 to 8 μm, and more preferably 3 to 7 μm from the viewpoint of uniformly uniting in the subsequent step 3 to produce toner particles. Is more preferable.

  Step 2 is a step of obtaining an aqueous dispersion of amorphous polyester (b). The method for obtaining an aqueous dispersion of amorphous polyester (b) and preferred physical properties are the same as those for the aqueous dispersion of amorphous polyester (a) in Step 1.

  The volume-median particle size of the amorphous polyester (b) in the aqueous dispersion obtained by the step 2 is the volume of the amorphous polyester (a) in the aqueous dispersion from the viewpoint of producing uniform core-shell particles. Similar to the unit particle size, 50 to 1000 nm is preferable, 50 to 500 nm is more preferable, 50 to 300 nm is further preferable, and 80 to 200 nm is still more preferable.

  In step 3, the aqueous dispersion of aggregated particles A obtained in step 1 and the aqueous dispersion of amorphous polyester (B) obtained in step 2 are mixed to aggregate the particles in the aqueous dispersion. This is a step of obtaining an aqueous dispersion of aggregated particles B.

  The amount of the amorphous polyester (b) in the aqueous dispersion to be mixed is preferably 5 to 200 parts by weight, more preferably 10 to 100 parts by weight with respect to 100 parts by weight of the aggregated particles A in the aqueous dispersion. 10 to 50 parts by weight is more preferable.

  The weight ratio of the amorphous polyester (a) to the amorphous polyester (b) in the agglomerated particles B obtained in step 3 is the same as that of the amorphous polyester (a) and the amorphous polyester (b). It is as the weight ratio.

  Aggregated particles B can be formed in the same manner as aggregated particles A in Step 1.

  The volume-median particle size of the aggregated particles B obtained in step 3 is preferably 1 to 10 μm, more preferably 2 to 8 μm, and more preferably 3 to 7 μm from the viewpoint of uniformly coalescing in the subsequent step 4 to produce toner particles. Is more preferable.

  Step 4 is a step of uniting the aggregated particles B obtained in Step 3.

  In step 4, the aggregated particles B obtained in step 3 can be united by heating.

  The temperature in the system in Step 4 is preferably maintained at 40 to 90 ° C., more preferably 50 to 80 ° C., from the viewpoints of the target toner particle size, particle size distribution, shape control and particle fusing property. Is preferred. The stirring speed is preferably a speed at which the aggregated particles do not settle.

  In addition, in order to control further aggregation at the same time, an aggregation terminator may be added.

  As the aggregation terminator, a surfactant is preferably used, and an anionic surfactant is more preferably used. Of the anionic surfactants, it is more preferable to use at least one selected from the group consisting of alkyl ether sulfates, alkyl sulfates, and linear alkylbenzene sulfonates.

  After coalescence, it is preferable to cool once, but from the viewpoint of achieving both low-temperature fixability and storage stability of the toner, the “melting point of crystalline polyester—30 ° C.” to “melting point of crystalline polyester—10 ° C.” In addition, it is preferable to raise the temperature to 40 ° C. to “temporary temperature−10 ° C.”.

  The coalesced particles obtained in the step 4 are appropriately subjected to a solid-liquid separation step such as filtration, a washing step, and a drying step, whereby a toner composed of core-shell particles can be obtained.

  In the washing step, an acid can be used to remove metal ions on the toner surface in order to ensure sufficient charging characteristics and reliability as the toner. When a nonionic surfactant is used, it is preferably removed completely by washing, and washing with an aqueous solution below the cloud point of the nonionic surfactant is preferred. The washing is preferably performed a plurality of times.

  In the drying step, any method such as a vibration type fluidized drying method, a freeze drying method, or a flash jet method can be employed.

  The volume median particle size of the electrophotographic toner of the present invention is preferably 1 to 10 μm, more preferably 2 to 8 μm, and even more preferably 3 to 7 μm, from the viewpoints of high image quality and productivity of the toner.

  Further, the softening point of the toner is preferably 60 to 130 ° C, more preferably 70 to 120 ° C, and further preferably 80 to 140 ° C, from the viewpoints of low-temperature fixability, chargeability, environmental stability and heat-resistant storage stability of the toner. .

  It is preferable that an external additive is added to the toner of the present invention. In particular, since the toner obtained through steps 1 to 4 has low fusibility at the time of external addition treatment, an auxiliary agent such as a fluidizing agent can be easily added to the toner particle surface as an external additive. Examples of the external additive include silica fine particles whose surface is hydrophobized, titanium oxide fine particles, alumina fine particles, cerium oxide fine particles, and inorganic fine particles such as carbon black; polymer fine particles such as polycarbonate, polymethyl methacrylate, and silicone resin, and the like. Fine particles can be used.

  The number average particle diameter of the external additive is preferably 4 to 200 nm, more preferably 8 to 30 nm. The number average particle diameter of the external additive is determined using a scanning electron microscope or a transmission electron microscope.

  The addition amount of the external additive is preferably 0.8 to 5 parts by weight, and 1 to 5 parts by weight with respect to 100 parts by weight of the toner before the treatment with the external additive, from the viewpoint of the environmental stability of the charging degree and the load storage stability. Parts are more preferred, and 1.5 to 3.5 parts by weight are even more preferred. However, when using hydrophobic silica as an external additive, by using 0.8 to 3.5 parts by weight of hydrophobic silica, preferably 1 to 3 parts by weight with respect to 100 parts by weight of toner before processing with the external additive, The desired effect can be obtained.

  The electrophotographic toner of the present invention can be used as a one-component developer or a two-component developer mixed with a carrier.

[Softening point of resin and toner]
Using a flow tester (Shimadzu Corporation, CFT-500D), a 1 g sample is heated at a heating rate of 6 ° C / min, and a 1.96 MPa load is applied by a plunger and extruded from a nozzle with a diameter of 1 mm and a length of 1 mm. . The amount of plunger drop of the flow tester is plotted against the temperature, and the temperature at which half of the sample flows out is taken as the softening point.

[Maximum peak temperature and melting point of resin endotherm]
Using a differential scanning calorimeter (Q-100 Japan, Q-100), weigh 0.01 to 0.02 g of the sample into an aluminum pan and cool it from room temperature to 0 ° C at a rate of 10 ° C / min. Then, it was left still for 1 minute. Thereafter, the measurement was carried out at a heating rate of 50 ° C./min. Of the endothermic peaks observed, the peak temperature on the highest temperature side was defined as the highest endothermic peak temperature. If the maximum peak temperature is within 20 ° C of the softening point, the peak temperature is taken as the melting point.

[Glass transition point of resin and toner]
Using a differential scanning calorimeter (Q-20, Japan, Q-20), weigh 0.01 to 0.02 g of the sample into an aluminum pan, raise the temperature to 200 ° C, and decrease the temperature from that temperature. The sample cooled to 0 ° C at 10 ° C / min is heated at a heating rate of 10 ° C / min, and the maximum slope from the peak rising portion to the peak apex is reached. The temperature at the intersection with the indicated tangent.

[Acid value of the resin]
Measured by the method of JIS K0070. However, only the measurement solvent is changed from the mixed solvent of ethanol and ether specified in JIS K0070 to the mixed solvent of acetone and toluene (acetone: toluene = 1: 1 (volume ratio)).

[Hydroxyl value of the resin]
Measured by the method of JIS K0070.

[Number average molecular weight and weight average molecular weight of the resin]
The molecular weight distribution is measured by the gel permeation chromatography (GPC) method according to the following method to determine the weight average molecular weight and the number average molecular weight.
(1) Preparation of sample solution A crystalline polyester sample is dissolved in chloroform at 25 ° C so that the concentration is 0.5 g / 100 ml. Next, this solution is filtered using a Terumo syringe 2.5 ml (ss-O2Lz) equipped with a fluororesin filter (manufactured by ADVANTEC, DISMIC-25JP) having a pore size of 0.2 μm to remove insoluble components to obtain a sample solution. When amorphous polyester is used, tetrahydrofuran is used instead of chloroform.
(2) Molecular weight measurement Chloroform (when crystalline polyester is used as a sample) or tetrahydrofuran (when amorphous polyester is used as a sample) as an eluent at a flow rate of 1 ml per minute using the following measuring apparatus and analytical column. Pour and stabilize the column in a constant temperature bath at 40 ° C. Measurement is performed by injecting 100 μl of the sample solution. The molecular weight of the sample is calculated based on a calibration curve prepared in advance. At this time, several types of monodisperse polystyrene (A-500 (5.0 × 10 ² ), A-1000 (1.01 × 10 ³ ), A-2500 (2.63 × 10 ³ ), A- 5000 (5.97 × 10 ³ ), F-1 (1.02 × 10 ⁴ ), F-2 (1.81 × 10 ⁴ ), F-4 (3.97 × 10 ⁴ ), F-10 (9.64 × 10 ⁴ ), F- 20 (1.90 × 10 ⁵ ), F-40 (4.27 × 10 ⁵ ), F-80 (7.06 × 10 ⁵ ), F-128 (1.09 × 10 ⁶ )) prepared as standard samples are used.
Measuring device: HLC-8220GPC (manufactured by Tosoh Corporation)
Analytical column: GMHXL + G3000HXL (manufactured by Tosoh Corporation)

[Content of cyclopentanone in polyester and toner]
A calibration curve using standard cyclopentanone (manufactured by Aldrich Co., Ltd.) is prepared using tetrahydrofuran (THF) as a solvent and toluene as an internal standard.
Next, 50 mg of polyester was dissolved in 3 g of tetrahydrofuran containing 3 g of internal standard (25 ° C.), and this solution was added to 2.5 ml of a Terumo syringe (ss- O2Lz) to remove insoluble components by filtration and use as a sample solution. Cyclopentanone is quantified by gas chromatography under the following conditions.
The amount of cyclopentanone in the toner is measured in the same manner except that the polyester is replaced with a toner. The cyclopentanone content in the polyester or toner was converted so as to be the cyclopentanone content in the total amount of polyester or toner including insoluble components.

<Gas chromatography measurement conditions>
(1) GC-conditions
Column: HP-1 Methyl Siloxane: 30m × 250μm × 1μm
Injection volume: 1μl
Oven program: 50 ℃ for 4min., 5 ℃ / min to 90 ℃
Runtime: 12min.
Heater: 250 ℃
Split ration: 50: 1
(2) MS information
Solvent delay: 4.00min.
EM Relative Voltage: 200V

[Melting point of release agent]
Using a differential scanning calorimeter (Q Instrument Japan, Q-20), the temperature was raised to 200 ° C, and the sample cooled to 0 ° C at a rate of 10 ° C / min was raised from that temperature. The temperature is raised at a rate of 10 ° C./min, and the maximum peak temperature of heat of fusion is taken as the melting point.

[Volume Median Particle Size (D ₅₀ )]
Using a laser diffraction particle size analyzer (SALD-2000J, manufactured by Shimadzu Corporation), add distilled water to the measurement cell and measure the volume-median particle size (D ₅₀ ) at a concentration where the absorbance is in the proper range. To do.

[Volume-median particle diameter of toner (D ₅₀ )]
Measuring machine: Coulter Multisizer II (Beckman Coulter, Inc.)
Aperture diameter: 50μm
Analysis software: Coulter Multisizer AccuComp version 1.19 (Beckman Coulter)
Electrolyte: Isoton II (Beckman Coulter, Inc.)
Dispersion: Emulgen 109P (manufactured by Kao Corporation, polyoxyethylene lauryl ether, HLB: 13.6) 5% electrolyte dispersion condition: 10 mg of measurement sample is added to 5 ml of dispersion, and dispersed for 1 minute with an ultrasonic disperser. Then, 25 ml of the electrolytic solution is added, and further dispersed with an ultrasonic disperser for 1 minute.
Measurement conditions: Add 100 ml of electrolyte and dispersion in a beaker, measure 30,000 particles at a concentration that can measure the particle size of 30,000 particles in 20 seconds, and determine the volume-median particle size ( determine the D _50).

Amorphous polyester production example 1 [resins AA to AF]
After stirring BPA-PO, BPA-EO, isophthalic acid, cyclopentanone (resins AB to AF), 40 g of tin (II) 2-ethylhexanoate and 3 g of gallic acid at 100 ° C., as shown in Table 1. The temperature was raised to 230 ° C. at 10 ° C./min, and the reaction was further performed at 230 ° C. for 5 hours. After the reaction, the temperature was lowered to 190 ° C., trimellitic anhydride was added, and the reaction was continued until the softening point shown in Table 1 was reached, thereby obtaining an amorphous polyester.

Production Example 2 of Amorphous Polyester [Resin AG]
After mixing 2g of BPA-PO, BPA-EO, adipic acid and sodium phosphate shown in Table 1 for 1 hour at 250 ° C, the temperature was lowered to 180 ° C and isophthalic acid, tin 2-ethylhexanoate (II) 40 g and 3 g of gallic acid were added, the temperature was raised to 230 ° C., and the reaction was further performed at 230 ° C. for 5 hours. After the reaction, the temperature was lowered to 190 ° C., trimellitic anhydride was added, and the reaction was continued until the softening point shown in Table 1 was reached, thereby obtaining an amorphous polyester.

Production Example 3 of Amorphous Polyester [Resin AH]
BPA-PO, BPA-EO, adipic acid, isophthalic acid, 40 g of tin (II) 2-ethylhexanoate and 3 g of gallic acid are added in the amounts shown in Table 1, and the temperature is raised to 230 ° C. Time reaction was performed. After the reaction, the temperature was lowered to 190 ° C., trimellitic anhydride was added, and the reaction was continued until the softening point shown in Table 1 was reached, thereby obtaining an amorphous polyester.

Production Example 4 of Amorphous Polyester [Resin B]
BPA-PO, BPA-EO, isophthalic acid, 40 g of tin (II) 2-ethylhexanoate and 3 g of gallic acid were added in the amounts shown in Table 1 and reacted at 230 ° C. for 5 hours. After the reaction, the temperature was lowered to 190 ° C., trimellitic anhydride was added and reacted for 1 hour, then the temperature was raised to 210 ° C. and the reaction was further continued for 1 hour. Thereafter, the reaction was carried out at 30 kPa until the softening point shown in Table 1 was reached, thereby obtaining an amorphous polyester.

Production Example 1 of Crystalline Polyester [Resin A-1]
Into a 10L four-necked flask equipped with a nitrogen inlet tube, dehydration tube, stirrer and thermocouple, the raw material monomer of the blending amount shown in Table 2 was placed, heated to 140 ° C and reacted for 6 hours (reaction The reaction was carried out while raising the temperature up to 200 ° C. at a rate of 10 ° C./hour. After reacting to a reaction rate of 80% at 200 ° C., 20 g of tin (II) 2-ethylhexanoate was added, and the reaction was further carried out at 200 ° C. for 2 hours. The reaction was further performed at 8 kPa for 2 hours to obtain a crystalline polyester.

Examples 1-7 and Comparative Examples 1-3
(Preparation of aqueous dispersion of amorphous polyester)
600 g of methyl ethyl ketone is put into a 5 L container equipped with a stirrer, reflux condenser, dropping funnel, thermometer and nitrogen introducing tube, and 200 g of amorphous polyester for core shown in Table 3 is added at 35 ° C. and dissolved. It was. 5% aqueous potassium hydroxide solution was added to the resulting solution to neutralize it to a degree of neutralization of 80 mol%, followed by addition of 2500 g of ion-exchanged water, followed by reduced pressure at a stirring speed of 250 r / min. Then, methyl ethyl ketone was distilled off at 70 ° C. to 30 ppm or less. The solid content concentration of the aqueous dispersion of amorphous polyester was measured, and ion-exchanged water was added so that the solid content concentration was 10% by weight to obtain an aqueous dispersion of resin. The volume-median particle size (D ₅₀ ) of the amorphous polyester fine particles was 150 nm. An aqueous dispersion of amorphous polyester for shell (resin B) was prepared in the same manner.

(Preparation of aqueous dispersion of crystalline polyester)
600 g of methyl ethyl ketone is put into a 5 L container equipped with a stirrer, reflux condenser, dropping funnel, thermometer and nitrogen introduction tube, and 200 g of crystalline polyester shown in Table 3 is added at 70 ° C. to dissolve the crystalline polyester. I let you. 5% aqueous potassium hydroxide solution was added to the resulting solution to neutralize it to a degree of neutralization of 80 mol%, followed by the addition of 2500 g of ion-exchanged water, followed by reduced pressure at a stirring speed of 250 r / min. Then, methyl ethyl ketone was distilled off at 70 ° C. to 30 ppm or less. The solid content concentration of the obtained crystalline polyester aqueous dispersion was measured, and ion-exchanged water was added so that the solid content concentration was 10% by weight to obtain a crystalline polyester dispersion.

[Preparation of aqueous dispersion of colorant]
Copper phthalocyanine (manufactured by Dainichi Seika Kogyo Co., Ltd., model number: “ECB-301”) 50 g, nonionic surfactant (manufactured by Kao Corporation, trade name: “Emulgen (registered trademark) 150”) 5 g and ion exchange 200 g of water was mixed, copper phthalocyanine was dispersed, and dispersed for 10 minutes using a homogenizer to obtain an aqueous dispersion of a colorant containing fine colorant particles. The volume median particle size (D ₅₀ ) of the colorant fine particles was 120 nm.

(Preparation of aqueous dispersion of release agent)
<Releasing agent A> (Examples and comparative examples other than Example 7)
Paraffin wax (manufactured by Nippon Seiwa Co., Ltd., trade name: “HNP-9”, melting point: 75 ° C.) 50 g, cationic surfactant (manufactured by Kao Corporation, trade name: “Sanisol (registered trademark) B50” ) 5g and 200g of ion-exchanged water were heated to 95 ° C, and the homogenizer was used to disperse the paraffin wax, followed by dispersion with a pressure discharge homogenizer, and the aqueous dispersion of the release agent containing the release agent fine particles. A liquid was obtained. The volume median particle size (D ₅₀ ) of the release agent fine particles was 550 nm.

<Releasing agent B> (Example 7)
Fischer-Tropsch Wax (Nippon Seiwa Co., Ltd., trade name: “FT-0070”, melting point: 72 ° C.) 50 g, cationic surfactant (Kao Co., Ltd., trade name: “Sanisol (registered trademark) B50 ”) 5 g and 200 g of ion-exchanged water were heated to 95 ° C., the paraffin wax was dispersed using a homogenizer, and then dispersed with a pressure discharge type homogenizer, and a release agent aqueous system containing release agent fine particles. A dispersion was obtained. The volume median particle size (D ₅₀ ) of the release agent fine particles was 550 nm.

(Preparation of charge control agent dispersion)
Charge control agent (Orient Chemical Industries, Ltd., trade name: “Bontron E-84”) 50 g, Nonionic surfactant (Kao Corporation, trade name: “Emulgen (registered trademark) 150”) 5 g And 200 g of ion-exchanged water were mixed and dispersed using a glass bead for 10 minutes using a sand grinder to obtain an aqueous dispersion of a charge control agent containing charge control agent fine particles. The volume median particle size (D ₅₀ ) of the charge control agent fine particles was 500 nm.

Examples 1-5, 7 and Comparative Examples 1-3
[Toner Preparation]
880 g of aqueous dispersion of core resin (aqueous dispersion of amorphous polyester / aqueous dispersion of crystalline polyester (weight ratio) = 9/1), 20 g of aqueous dispersion of colorant, aqueous dispersion of release agent 40 g, 4 g of aqueous dispersion of charge control agent, and 1.5 g of cationic surfactant (Sanisol B50, trade name, manufactured by Kao Corporation) at 100 r / min with a Kai-type stirrer in a round stainless steel flask After stirring and dispersing, the flask was heated to 48 ° C. with stirring in a heating oil bath. Furthermore, it was kept at 48 ° C. for 1 hour to form aggregated particles. At this time, the volume-median particle size of the aggregated particles was 5.1 μm. Thereafter, 200 g of an aqueous dispersion of an amorphous polyester for a shell was added and dispersed by stirring at 60 ° C. to obtain aggregated particles having an encapsulated core-shell structure. At this time, the volume median particle size of the aggregated particles was 5.4 μm.

After adding 3 g of an anionic surfactant (Perex SS-L, trade name, manufactured by Kao Corporation, sodium alkyldiphenyl ether disulfonate) to the aggregated particle dispersion in which the core-shell aggregated particles are formed, the mixture is refluxed to the stainless steel flask. A tube was attached, and the mixture was heated to 80 ° C. at a rate of 0.1 ° C./min while continuing stirring, and held for 2 hours to coalesce the aggregated particles. Then, it cooled to 30 degreeC, hold | maintained for 20 minutes, heated up to 50 degreeC, and hold | maintained for 2 hours. Thereafter, the mixture was cooled again, the coalesced particles were filtered, thoroughly washed with ion exchange water, and then dried to obtain toner particles. The obtained toner particles were core-shell particles composed of a core portion and a shell portion, and the volume-median particle size (D ₅₀ ) thereof was about 5.0 μm.

  Furthermore, hydrophobic silica “NAX-50” (trade name, manufactured by Nippon Aerosil Co., Ltd., number average particle diameter 40 nm) 2.0 parts by weight, hydrophobic silica “R972” (trade name, Japan) with respect to 100 parts by weight of toner particles. Aerosil Co., Ltd., number average particle diameter 16 nm) 1.5 parts by weight, 10 L Henschel mixer (Mitsui Mining Co., Ltd.) equipped with ST (upper blade) -A0 (lower blade) type stirring blade The mixture was stirred for 2 minutes at 3000 r / min for external addition to obtain a toner.

Example 6
[Toner Preparation]
880 g of aqueous dispersion of core resin (aqueous dispersion of amorphous polyester / aqueous dispersion of crystalline polyester (weight ratio) = 9/1), 20 g of aqueous dispersion of colorant, aqueous dispersion of release agent 40 g, 4 g of an aqueous dispersion of a charge control agent, 1.5 g of a cationic surfactant (Sanisol B50, trade name, manufactured by Kao Corporation), and 0.3 g of cyclopentanone in a round stainless steel flask After mixing and dispersing with stirring at 100 r / min with a stirrer, the flask was heated to 48 ° C. with stirring in an oil bath for heating. Furthermore, it was kept at 48 ° C. for 1 hour to form aggregated particles. At this time, the volume-median particle size of the aggregated particles was 5.1 μm. Thereafter, 200 g of an aqueous dispersion of an amorphous polyester for shell was added, and the mixture was stirred and dispersed at 60 ° C. to obtain aggregated particles having an encapsulated core-shell structure. Was 5.4 μm.

  Thereafter, in the same manner as in Example 1, from the coalescence and fusion of the core-shell aggregated particles to the external addition treatment, a toner was obtained.

[Measurement of content of release agent in toner]
Using DSC (Q-100, manufactured by TA Instruments), the temperature of the release agent used in the toner was raised from 0 ° C to 150 ° C at 5 ° C / min, and the endothermic amount of the release agent was measured. .
The value of (endothermic amount of release agent) × (theoretical weight ratio of release agent in core-shell particles (excluding surfactant and external additive)) and the theoretical value of endothermic amount of release agent To do.
The obtained toner was heated from 0 ° C. to 200 ° C. at 5 ° C./min, then rapidly cooled to 100 ° C./min to 0 ° C., and then heated from 0 ° C. to 150 ° C. at 5 ° C./min. The endothermic amount of the release agent was measured. This value is taken as an actual measurement value.
Based on the measured value and the theoretical value of the endothermic amount of the release agent, the content of the release agent in the toner was evaluated according to the following evaluation criteria. The results are shown in Table 3.

〔Evaluation criteria〕
The ratio between the measured value and the theoretical value of the endotherm of the release agent [actual value / theoretical value x 100] (%)
A: 90% or more B: 80% or more, less than 90% C: 60% or more, less than 80% D: less than 60% Ratio of the measured value and the theoretical value of the endotherm of the release agent [actual value / theoretical value × 100 ] (%) Is closer to 100%, indicating that the release agent is incorporated into the toner as theoretically.

Test example (offset resistance)
Toner was mounted on a copier “AR-505” (manufactured by Sharp) and an image was printed without fixing (printing area: 2 cm × 12 cm, adhesion amount: 0.5 mg / cm ² ). The fixing machine of the copying machine was fixed offline at 300 mm / sec while the fixing temperature was increased from 70 ° C. to 200 ° C. in steps of 5 ° C. in order. As the fixing paper, “CopyBond SF-70NA” (manufactured by Sharp Corporation, 75 g / m ² ) was used. The offset resistance was evaluated according to the following evaluation criteria. The results are shown in Table 3.

〔Evaluation criteria〕
The temperature at which hot offset is observed is
A: 200 ° C or higher (no hot offset observed even at 200 ° C)
B: 190 ° C or higher and lower than 200 ° C C: 170 ° C or higher and lower than 190 ° C D: Less than 170 ° C

  From the above results, it can be seen that the toners of Examples 1 to 7 have better offset resistance than Comparative Examples 1 to 3.

  The toner for electrophotography of the present invention is suitably used for developing a latent image formed in electrophotography, electrostatic recording method, electrostatic printing method and the like.

Claims (6)

  An electrophotographic toner comprising a binder resin containing amorphous polyester, a release agent, and cyclopentanone, wherein the content of cyclopentanone is 5 to 150 ppm.   2. The electrophotographic toner according to claim 1, wherein the release agent is at least one mineral / petroleum wax selected from montan wax, paraffin wax, ozokerite, ceresin, microcrystalline wax, and Fischer-Tropsch wax. The amorphous polyester has the formula (I):

(In the formula, R ¹ O and OR ¹ are oxyalkylene groups, R ¹ is an ethylene and / or propylene group, x and y indicate the number of added moles of alkylene oxide, and each is a positive number; The average value of the sum of y and y is 1-16.)
The electrophotographic toner according to claim 1, which is a polyester obtained by polycondensation of an alcohol component and a carboxylic acid component containing 70 to 100 mol% of an alkylene oxide adduct of bisphenol A represented by the formula:   The toner for electrophotography according to claim 1, wherein the toner comprises core-shell particles composed of a core part and a shell part, and the core part contains amorphous polyester, a release agent, and cyclopentanone.   5. The electrophotographic apparatus according to claim 4, wherein the softening point of the amorphous polyester contained in the core part is 68 to 100 ° C., and the shell part contains amorphous polyester having a softening point of more than 100 ° C. and 160 ° C. or less. toner.   6. The method for producing an electrophotographic toner according to claim 1, wherein an aqueous dispersion of an amorphous polyester containing cyclopentanone and an aqueous dispersion of a release agent are mixed to form an aqueous dispersion. A method for producing an electrophotographic toner, comprising a step of aggregating particles therein to obtain an aqueous dispersion of aggregated particles.