JP5597987B2 - Toner for electrostatic image development - Google Patents

Description

  The present invention relates to an electrostatic charge image developing toner used for developing an electrostatic latent image formed on a photoreceptor in an electrophotographic (including electrostatic printing) image forming apparatus. More specifically, the present invention relates to a toner for developing an electrostatic charge image that contains a fatty acid ester compound that acts as a softening agent and is excellent in fixability, storage stability (blocking resistance), peelability, fine line reproducibility, and the like.

  In an image forming apparatus such as an electrophotographic copying machine or printer in which an electrostatic charge image developing toner is used, there are increasing demands for higher printing speed, lower fixing temperature, and full color. By lowering the fixing temperature of the electrostatic image developing toner, it is possible to cope with high-speed printing and full-color printing, and power consumption can be reduced. On the other hand, when the toner composition is designed so as to lower the fixing temperature of the electrostatic image developing toner, the toner composition is likely to aggregate, and the blocking resistance and peelability (peelability) are reduced.

  For example, in order to obtain a toner for developing an electrostatic image having good low-temperature fixability, a method of incorporating a low softening point material having releasability and releasability such as paraffin wax is known. However, the toner for developing an electrostatic charge image containing such a low softening point substance tends to aggregate during storage, and the blocking resistance is lowered. In addition, in a fixing process of a printer, a fixing roll and a recording medium are used. Can not be peeled off, causing paper jams.

  Conventionally, a fatty acid ester of a polyhydric alcohol is used in the toner in order to obtain a toner for developing an electrostatic image having an excellent balance of low-temperature fixability, blocking resistance and peelability, high fine line reproducibility and capable of high-quality printing. Various methods for incorporating compounds have been proposed.

  For example, Japanese Patent Application Laid-Open No. 2001-147550 (Patent Document 1) discloses that in an electrostatic charge image developing toner containing at least a binder resin, a colorant, and a polyfunctional ester compound, the polyfunctional ester compound is contained in a molecule. An electrostatic charge image developing toner having 5 or more ester bonds, a molecular weight of 2,000 or more, a dissolution amount with respect to 100 g of styrene measured at 35 ° C. of 5 g or more, and an acid value of 2 mgKOH / g or less. It is disclosed. In Examples of Patent Document 1, hexaglycerin tetrastearate tetrabehenate, hexaglycerin tetrastearate dibehenate, pentaerythritol tetrabehenate, and triglycerin pentastearate are shown as polyfunctional ester compounds. ing. However, electrostatic charge image developing toners containing these polyfunctional ester compounds tend to aggregate when placed in a high-temperature atmosphere for a long time, and the anti-blocking property is not sufficient.

  Japanese Patent Application Laid-Open No. 2003-241418 (Patent Document 2) discloses polyglycerol fatty acid esters of two or more fatty acids selected from saturated fatty acids having 8 to 22 carbon atoms and low-temperature fixability for toner. A method for use as an anti-blocking agent is disclosed. However, the electrostatic image developing toner containing a polyglycerin fatty acid ester of two or more fatty acids disclosed in Patent Document 2 is inferior in continuous printing characteristics after being left in a high-temperature atmosphere and does not have sufficient blocking resistance. Absent.

  JP 2006-98745 A (Patent Document 3) discloses a polymerized toner containing an ester of a trivalent or higher alcohol and a fatty acid having 12 to 22 carbon atoms as a release agent. In Examples of Patent Document 3, dipentaerythritol hexamyristate and pentaerythritol tetrastearate are used as the ester. However, the toner for developing an electrostatic charge image containing these fatty acid ester compounds does not have sufficient continuous printing characteristics after being left in a high temperature atmosphere, and further improvement is required. In addition, in the toner for developing an electrostatic charge image containing these fatty acid ester compounds, whitening of the developing roll due to precipitation of the fatty acid ester compounds is observed, and contamination of each part of the apparatus and a tendency to decrease blocking resistance are observed.

  Further, JP-A-2008-225094 (Patent Document 4) discloses an electrostatic image development in which 90% or more of fatty acid residues have 20 to 25 carbon atoms and a hydroxyl value of 8.0 mgKOH / g or less. Toner is disclosed. Even when placed in a high temperature atmosphere for a long time, it is said to be excellent in durability and blocking resistance. However, since the fatty acid ester compound described in Patent Document 4 has a small residual amount of OH groups and a low polarity, it is difficult to move to the interface between the recording medium and the fixing roll at the time of fixing, so that sufficient peelability can be obtained. Have difficulty.

JP 2001-147550 A JP 2003-241418 A JP 2006-98745 A JP 2008-225094 A

  In recent years, image forming apparatuses such as electrophotographic copying machines and printers are strongly required to be lighter, smaller, and more functional. Further, the integration of the image forming apparatus with other equipment such as a facsimile is being promoted, and a compact design is required to save space. For this reason, it exists in the tendency for the temperature inside an apparatus to become high. Further, image forming apparatuses are increasingly used in areas where the annual average temperature is high.

  For this reason, the toner for developing electrostatic images has excellent blocking resistance even when placed in a high temperature atmosphere for a long time, and has excellent low-temperature fixability and peelability, as well as stable high-definition images. Therefore, it is required to be formed. However, conventional electrostatic image developing toners containing fatty acid ester compounds cannot sufficiently meet these requirements.

  An object of the present invention is to provide a toner for developing an electrostatic charge image that has an excellent balance of low-temperature fixability, blocking resistance and peelability and is capable of high-quality printing.

  More specifically, an object of the present invention is to develop an electrostatic charge image that contains a fatty acid ester compound that acts as a softening agent and is excellent in low-temperature fixability, storage stability (blocking resistance), releasability, and fine line reproducibility. It is to provide a toner.

  As a result of diligent research to solve the above-mentioned problems, the present inventors are a fatty acid ester compound of a polyhydric alcohol mixture containing at least tetrafunctional to octafunctional polyhydric alcohol and a fatty acid, and having a specific composition And an electrostatic charge image developing toner containing a fatty acid ester compound having the above characteristics.

  The fatty acid ester compound used in the present invention plays a role of contributing to toner properties such as peelability and low-temperature fixability. The toner for developing an electrostatic charge image containing the fatty acid ester compound seems to have a remarkably low degree of aggregation and a high limit peeling temperature even when placed in a high temperature atmosphere for a long time. In addition, it is excellent in durability, blocking resistance and peelability, and further has low-temperature fixability, high fine line reproducibility, and can form a high-definition image. The present invention has been completed based on these findings.

According to the present invention, colored resin particles containing a binder resin, a colorant, a charge control agent, and a fatty acid ester compound , or core-shell type coloring in which a shell made of a polymer layer is further formed on the surface of the colored resin particles. In the electrostatic image developing toner containing resin particles, the fatty acid ester compound is:
(A) a fatty acid ester compound of a polyhydric alcohol mixture containing a bifunctional or higher polyhydric alcohol and a fatty acid,
(B) The content ratio of the fatty acid ester compound of a polyfunctional alcohol having 4 or less functional groups is 10% by weight or less,
(C) The content ratio of the fatty acid ester compound of the polyfunctional alcohol having 8 or more functional groups is 15% by weight or more,
(D) 90% by weight or more of the fatty acid residues have 20 to 25 carbon atoms,
(E) the hydroxyl value is 10-20 mg KOH / g, and
Containing 1 to 9 parts by weight of the fatty acid ester compound with respect to 100 parts by weight of the binder resin;
An electrostatic charge image developing toner is provided.

  According to the present invention, an electrostatic charge image developing toner having excellent durability, blocking resistance and peelability, low temperature fixability and high fine line reproducibility even when placed in a high temperature atmosphere for a long time. Is provided. In particular, according to the present invention, it contains a fatty acid ester compound that acts as a softening agent, is excellent in fixability, storage stability, durability, and the like, even when placed in a high temperature atmosphere for a long time. Provided is a toner for developing an electrostatic image in which deterioration of various properties is suppressed.

  The fatty acid ester compound used in the present invention is a fatty acid ester compound of a polyhydric alcohol mixture containing a bifunctional or higher polyhydric alcohol and a fatty acid. The fatty acid ester compound is a partial ester compound of a fatty acid having a predetermined hydroxyl value.

In the fatty acid ester compound used in the present invention, the content of the fatty acid ester compound of a polyfunctional alcohol having 4 or less functional groups is 10% by weight or less, preferably 8% by weight or less, more preferably 5% by weight or less, and 8 The content ratio of the fatty acid ester compound of the functional or higher polyhydric alcohol is 15% by weight or more, preferably 18 to 35% by weight, more preferably 20 to 30% by weight. The fatty acid ester compound is a fatty acid ester compound of a pentafunctional to heptofunctional polyhydric alcohol , preferably in a proportion of preferably 15% by weight or more, more preferably 18 to 35% by weight, particularly preferably 20 to 30% by weight. It is desirable to contain.

  In the fatty acid ester compound used in the present invention, 90% by weight or more, preferably 95% by weight or more, more preferably 98% by weight or more of the fatty acid residue has 20 to 25 carbon atoms. The number of carbon atoms of the fatty acid residue is preferably 21 to 24, particularly preferably 22.

  In the present invention, the ratio of each functional fatty acid ester compound and the ratio of the carbon number of the aliphatic residue are analytical values obtained by GC-MS (gas chromatography / mass spectrometry) measurement. The number of functional groups (OH groups) of the starting polyhydric alcohol and the number of carbons of the long-chain fatty acid are indicated by the number of functional groups and the number of carbons of the main component. It is necessary to actually measure these values.

When the fatty acid ester compound used in the present invention has the selected composition, the object of the present invention can be achieved. If the content ratio of the fatty acid ester compound of the polyfunctional alcohol of tetrafunctional or lower is too high or the content ratio of the fatty acid ester compound of the polyfunctional alcohol of 8 functional or higher is too low, the blocking resistance after leaving in a high temperature atmosphere, Peelability and fine line reproducibility are reduced. When the proportion of the fatty acid residue having 20 to 25 carbon atoms in the fatty acid ester compound is too low, the blocking resistance after leaving in a high temperature atmosphere is remarkably deteriorated, or the fine line reproducibility is lowered.

  The hydroxyl value of the fatty acid ester compound used in the present invention is in the range of 10 to 20 mgKOH / g, preferably 11 to 18 mgKOH / g, more preferably 12 to 16 mgKOH / g. When the hydroxyl value of the fatty acid ester compound is too high, when producing a polymerized toner, it has an adverse effect when granulating droplets of the monomer composition containing the fatty acid ester compound in an aqueous dispersion medium. As a result, it becomes difficult to granulate droplet particles having a uniform and stable distribution. As a result, the toner particles tend to aggregate and the blocking resistance is deteriorated. In addition, a toner containing a fatty acid ester compound having a hydroxyl value that is too high becomes unstable in chargeability under high temperature and high humidity, deteriorates reproducibility of fine lines, and makes it difficult to obtain a sufficient image density. On the other hand, if the hydroxyl value of the fatty acid ester compound is too low, the residual amount of OH groups is small and the polarity is low, so that the toner is less likely to move to the interface between the recording medium and the fixing roll during fixing. It becomes difficult to obtain.

  The average molecular weight of the fatty acid ester compound used in the present invention is preferably 2,000 to 6,000, more preferably 2,300 to 4,000, particularly preferably 2,500 to 3,500. If the average molecular weight of the fatty acid ester compound is too high, it is difficult to lower the fixing temperature, and offset resistance becomes insufficient. If the average molecular weight of the fatty acid ester compound is too low, the melting point of the fatty acid ester compound itself becomes low, and the fatty acid ester compound is likely to precipitate (bleed) from the toner during storage of the toner or in a high temperature environment in the toner box of the developing device. As a result, the toner may agglomerate or the bleed-out fatty acid ester compound crystals may grow greatly. If the fatty acid ester compound is deposited during printing, each part of the apparatus is contaminated, which may cause toner filming on the developing roll, the photoreceptor surface, and the like. The average molecular weight of the fatty acid ester compound can be obtained as a standard polystyrene conversion value measured using gel permeation chromatography (GPC). The average molecular weight of the fatty acid ester compound can also be calculated by calculation from the average molecular weight (calculated value) of the polyhydric alcohol used for esterification and the molecular weight of the fatty acid.

  The fatty acid ester compound used in the present invention preferably exhibits a maximum endothermic peak in the region of 50 to 80 ° C. at the time of temperature rise in the DSC curve measured by a differential scanning calorimeter. A fatty acid ester compound having a maximum endothermic peak temperature of 50 to 80 ° C. can contribute to the low-temperature fixability of the toner. The maximum endothermic peak temperature is preferably 55 to 78 ° C, particularly preferably 60 to 75 ° C.

  The fatty acid ester compound used in the present invention can be obtained by esterifying a polyhydric alcohol mixture containing at least tetrafunctional to octafunctional polyhydric alcohol and a fatty acid having 20 to 25 carbon atoms.

  The molecular weight of the polyhydric alcohol is preferably 100 to 1,500, more preferably 200 to 1,000, and particularly preferably 300 to 800. Therefore, the average molecular weight of the polyhydric alcohol mixture is also within the above range. A fatty acid ester compound using a polyhydric alcohol having a molecular weight that is too large tends to reduce the peeling effect of the fatty acid component.

  Examples of the polyhydric alcohol include glycerin dehydration condensate (polycondensate), carbohydrates or dehydration condensate thereof. Among these, glycerin polycondensate (polyglycerin) is preferable. Therefore, the polyhydric alcohol mixture is preferably a glycerin polycondensate mixture having a different degree of polycondensation. Glycerin and polyglycerin can be represented by the following formula.

  When n = 1, the monomer is a glycerin, and the number of hydroxyl groups (number of functional groups) is three. When n = 2, it is a dimer of glycerin, and the number of functional groups thereof is four. As n increases by 1, the number of functional groups increases by one. That is, the number of functional groups = 3 + (n−1). When n = 6, it is a glycerin hexamer, and the number of functional groups thereof is eight.

  When dehydrating polycondensation of glycerin, a mixture of glycerin polycondensates having different degrees of polymerization is obtained. In the present invention, it is preferable to use polyglycerin containing at least a dimer to hexamer glycerin polycondensate mixture as the polyhydric alcohol mixture. This polyglycerin may contain a glycerin monomer and / or a polyglycerin of 7-mer or more.

As the polyglycerin, the fatty acid ester compound finally obtained has a content ratio of a fatty acid ester compound of a polyfunctional alcohol having 4 or less functional groups of 10% by weight or less, preferably 8% by weight or less, more preferably 5% by weight or less. And a polyhydric alcohol having a functional group distribution such that the content of the fatty acid ester compound of the polyhydric alcohol having 8 or more functional groups is 15% by weight or more, preferably 18 to 35% by weight, more preferably 20 to 30% by weight. Use glycerin. Furthermore, in polyglycerin, the content ratio of each fatty acid ester compound of a pentafunctional to 7 functional polyhydric alcohol is 15% by weight or more, more preferably 18 to 35% by weight, and particularly preferably 20 to 30% by weight. It is preferable to have a functional group distribution capable of providing such a fatty acid ester compound. Such polyglycerin is dehydrated and polycondensed under conditions such that the average degree of polycondensation of glycerin is 6 or more, and polycondensation is performed so that the distribution from the diglycerin polycondensate to the decaglycerin polycondensate is broadened. It can be obtained by setting conditions.

  The fatty acid ester compound can be obtained by esterifying the polyglycerin and a fatty acid having 20 to 25 carbon atoms. The fatty acid having 20 to 25 carbon atoms is preferably a saturated fatty acid. In that case, it is preferable to use a high-purity saturated fatty acid so that the resulting fatty acid ester compound has the distribution of the number of functional groups as described above. Moreover, the fatty acid ester compound whose 90 weight% or more of a fatty acid residue is a C20-C25 can be obtained by using a C20-C25 high purity saturated fatty acid.

  The fatty acid is a saturated or unsaturated fatty acid having 20 to 25, preferably 22 to 24 carbon atoms, and more preferably a saturated fatty acid. Examples of such fatty acids include saturated higher fatty acids such as icosanoic acid (20 carbon atoms), behenic acid (22 carbon atoms), lignoceric acid (24 carbon atoms); higher unsaturated fatty acids such as erucic acid (22 carbon atoms). ; Among these, behenic acid is particularly preferable.

  When a fatty acid ester compound obtained using a fatty acid having a small number of carbon atoms is used, the durability of the toner for developing an electrostatic image held in a high-temperature atmosphere tends to decrease, and the cohesiveness increases, Whitening. It is preferable that the fatty acid used for the synthesis | combination of the fatty acid ester compound used by this invention is 1 type, and it is more preferable that it is only behenic acid. Conventionally, a fatty acid ester compound synthesized using two types of fatty acids having different carbon numbers has been considered preferable because the crystallinity is lowered and the amount of heat required for melting during toner fixing is reduced. However, when a fatty acid ester compound obtained by using a fatty acid having a carbon number of less than 20 and a fatty acid having a carbon number of 20 or more is used, the durability of the toner for developing an electrostatic charge image held in a high temperature atmosphere tends to decrease. In addition, the cohesiveness is remarkably increased and the developing roll is whitened. Therefore, the fatty acid ester compound used in the present invention requires that 90% by weight or more of the fatty acid residues have 20 to 25 carbon atoms.

  In the fatty acid ester compound used in the present invention, it is necessary to adjust the esterification reaction rate between a polyhydric alcohol such as polyglycerin and a fatty acid so that the hydroxyl value is in the range of 10 to 20 mgKOH / g. . For that purpose, it is preferable to react less than an equivalent amount of fatty acid with respect to the polyhydric alcohol during the esterification reaction and to purify the reaction product.

The proportion of the fatty acid ester compound used is usually 1 to 10 parts by weight, preferably 1.5 to 9 parts by weight, per 100 parts by weight of the toner binder resin (or polymerizable monomer forming the binder resin). More preferably, it is 2 to 8 parts by weight, particularly preferably 3 to 7 parts by weight. In this invention, it is 1-9 weight part. If the use ratio of the fatty acid ester compound is too low, it becomes difficult to obtain a toner having excellent low-temperature fixability and high fine line reproducibility. If the use ratio of the fatty acid ester compound is too high, toner filming on the surface of the photoconductor is likely to occur or precipitate from the toner surface.

  The toner for developing an electrostatic charge image of the present invention is preferably colored resin particles containing a binder resin, a colorant, a charge control agent, and the fatty acid ester compound. The colored resin particles are also called toner particles, and in the case of a polymerized toner, they may be called colored polymer particles. The electrostatic charge image developing toner of the present invention may be core-shell type colored resin particles (capsule toner) in which a shell made of a polymer layer is further formed on the surface of the colored resin particles.

  Examples of the method for producing the electrostatic image developing toner of the present invention include a pulverization method and a polymerization method. Examples of the polymerization method include an emulsion polymerization method, an aggregation method, a dispersion polymerization method, and a suspension polymerization method. According to the polymerization method, micron-order toner particles can be obtained directly with a relatively small particle size distribution. The toner for developing an electrostatic charge image of the present invention is particularly preferably a polymerized toner obtained by a suspension polymerization method from the viewpoint of developer characteristics.

  A polymerized toner by suspension polymerization suspends a polymerizable monomer composition containing at least a polymerizable monomer, a colorant, a charge control agent, and a fatty acid ester compound in an aqueous dispersion medium containing a dispersion stabilizer. It can be obtained by suspension polymerization. A polymer formed by polymerization of the polymerizable monomer serves as a binder resin. The polymerized toner having a core-shell structure can be produced by a method such as a spray dry method, an interfacial reaction method, an in situ polymerization method, or a phase separation method. In particular, the in situ polymerization method and the phase separation method are preferable because of high production efficiency. Specifically, it is obtained by suspension polymerization of a polymerizable monomer composition containing at least a polymerizable monomer, a colorant, and a fatty acid ester compound in an aqueous dispersion medium containing a dispersion stabilizer. It can be obtained by using the colored resin particles as a core and subjecting the polymerizable monomer for shell to suspension polymerization in the presence of the core. A polymer layer formed by polymerization of the shell monomer is a resin coating layer. The polymerizable monomer composition may contain various additives such as a crosslinkable monomer, a macromonomer, a molecular weight modifier, a general-purpose release agent, a lubricant, and a dispersion aid, as necessary. .

  As the polymerizable monomer, a monovinyl monomer is preferable. Specifically, styrene monomers such as styrene, vinyl toluene, α-methyl styrene; acrylic acid, methacrylic acid; methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, Acrylic acid or methacrylic such as dimethylaminoethyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, dimethylaminoethyl methacrylate, acrylonitrile, methacrylonitrile, acrylamide, methacrylamide Derivatives of acids; Ethylenically unsaturated monoolefins such as ethylene, propylene and butylene; Vinyl halides such as vinyl chloride, vinylidene chloride and vinyl fluoride; Vinyls such as vinyl acetate and vinyl propionate Esters; vinyl ethers such as vinyl methyl ether and vinyl ethyl ether; vinyl ketones such as vinyl methyl ketone and methyl isopropenyl ketone; nitrogen-containing vinyl compounds such as 2-vinyl pyridine, 4-vinyl pyridine and N-vinyl pyrrolidone; . Monovinyl monomers can be used alone or in combination of a plurality of monomers. Of the monovinyl monomers, it is preferable to use a styrene monomer and a (meth) acrylic acid derivative in combination.

  Use of a crosslinkable monomer and / or a crosslinkable polymer together with the polymerizable monomer is effective in improving hot offset resistance. The crosslinkable monomer is a monomer having two or more polymerizable carbon-carbon unsaturated double bonds, and examples thereof include aromatic divinyl compounds such as divinylbenzene, divinylnaphthalene, and derivatives thereof; Diethylenically unsaturated carboxylic acid esters such as methacrylate and diethylene glycol dimethacrylate; (meth) acrylates derived from aliphatic terminal alcohols such as 1,4-butanediol and 1,9-nonanediol; N, N-divinylaniline, di And divinyl compounds such as vinyl ether; compounds having three or more vinyl groups; and the like.

  Examples of the crosslinkable polymer include polyethylene, polypropylene, polyester and polysiloxane-derived (meth) acrylate having two or more hydroxyl groups in the molecule. These crosslinkable monomers and crosslinkable polymers can be used alone or in combination of two or more. The crosslinkable monomer and / or crosslinkable polymer is usually 10 parts by weight or less, preferably 0.01 to 5 parts by weight, more preferably 0.1 to 2 parts per 100 parts by weight of the polymerizable monomer. Used in parts by weight.

  When a macromonomer is used together with a polymerizable monomer, the balance between storage stability, offset prevention property and low-temperature fixability can be improved. A macromonomer is a relatively long linear molecule having a polymerizable functional group (for example, an unsaturated group such as a carbon-carbon double bond) at the end of a molecular chain. As the macromonomer, an oligomer or polymer having a number average molecular weight of usually 1,000 to 30,000 is preferable. When a macromonomer having a small number average molecular weight is used, the surface portion of the toner particles becomes soft and the storage stability is lowered. On the other hand, if a macromonomer having a large number average molecular weight is used, the meltability of the macromonomer is poor and the fixing property of the toner is lowered.

  Specific examples of the macromonomer include styrene, a styrene derivative, a methacrylic acid ester, an acrylic acid ester, acrylonitrile, a methacrylonitrile, a polymer obtained by polymerizing two or more kinds alone, and a macromonomer having a polysiloxane skeleton. Etc. Among the macromonomers, a polymer having a glass transition temperature higher than the glass transition temperature of the binder resin is preferable, and a copolymer macromonomer or polymethacrylic acid ester macromonomer of styrene and methacrylic acid ester and / or acrylic acid ester is particularly preferable. Is preferred. When using a macromonomer, the blending ratio is usually 0.01 to 10 parts by weight, preferably 0.03 to 5 parts by weight, more preferably 0.05 to 100 parts by weight with respect to 100 parts by weight of the polymerizable monomer. 1 part by weight. When the proportion of the macromonomer used is too high, the fixability tends to decrease.

  As the colorant, various pigments and dyes used in the field of toner such as carbon black and titanium white can be used. Examples of the black colorant include carbon black and nigrosine-based dyes and pigments; magnetic particles such as cobalt, nickel, iron tetroxide, manganese iron oxide, zinc iron oxide, and nickel iron oxide. When carbon black is used, it is preferable to use carbon black having a primary particle size of 20 to 40 nm because good image quality can be obtained and the safety of the toner to the environment is enhanced.

  As a color toner colorant, a yellow colorant, a magenta colorant, a cyan colorant, or the like can be used. Examples of the yellow colorant include C.I. I. Pigment Yellow 3, 12, 13, 14, 15, 17, 62, 65, 73, 83, 90, 93, 97, 120, 138, 155, 180, 181; Nephthol Yellow S, Hansa Yellow G, C.I. I. Examples thereof include bat yellow.

  Examples of the magenta colorant include azo pigments and condensed polycyclic pigments. More specifically, for example, C.I. I. Pigment Red 48, 57, 58, 60, 63, 64, 68, 81, 83, 87, 88, 89, 90, 112, 114, 122, 123, 144, 146, 149, 163, 170, 184, 185, 187, 202, 206, 207, 209, 251; C.I. I. Pigment violet 19 and the like.

  Examples of cyan colorants include copper phthalocyanine compounds and derivatives thereof, anthraquinone compounds, and the like. I. Pigment blue 2, 3, 6, 15, 15: 1, 15: 2, 15: 3, 15: 4, 16, 17, 60; phthalocyanine blue, C.I. I. Bat Blue, C.I. I. Acid blue and so on. The colorant is generally used in a proportion of 0.1 to 50 parts by weight, preferably 1 to 20 parts by weight, with respect to 100 parts by weight of the binder resin or the polymerizable monomer forming the binder resin.

  Examples of the molecular weight modifier include mercaptans such as t-dodecyl mercaptan, n-dodecyl mercaptan and n-octyl mercaptan; halogenated hydrocarbons such as carbon tetrachloride and carbon tetrabromide; These molecular weight modifiers can be added before or during polymerization. The molecular weight modifier is usually used in a proportion of 0.01 to 10 parts by weight, preferably 0.1 to 5 parts by weight, with respect to 100 parts by weight of the polymerizable monomer.

  For uniform dispersion of the colorant, lubricants such as fatty acids such as oleic acid and stearic acid, fatty acid metal salts composed of fatty acids and metals such as Na, K, Ca, Mg and Zn; silane or titanium coupling agents Dispersion aids such as: can be used. The lubricant and the dispersant are usually used in a ratio of about 1/1000 to 1/1 based on the weight of the colorant.

  In order to improve the chargeability of the toner, it is preferable to use various positively or negatively chargeable charge control agents. Examples of the charge control agent include Bontron N01 (manufactured by Orient Chemical Co., Ltd.), Nigrosine Base EX (manufactured by Orient Chemical Co., Ltd.), Spiron Black TRH (manufactured by Hodogaya Chemical Co., Ltd.), and T-77 (manufactured). Tsuchiya Chemical Industry Co., Ltd.), Bontron S-34 (Orient Chemical Industry Co., Ltd.), Bontron E-81 (Orient Chemical Industry Co., Ltd.), Bontron E-84 (Orient Chemical Industry Co., Ltd.), Bontron E- 89 (manufactured by Orient Chemical Co., Ltd.), Bontron F-21 (manufactured by Orient Chemical Co., Ltd.), COPY CHRGE NX VP434 (manufactured by Clariant Japan Co., Ltd.), COPY CHRGE NEG VP2036 (manufactured by Clariant Japan Co., Ltd.), TNS-4 -1 (Hodogaya Chemical Co., Ltd. made , TNS-4-2 (manufactured by Hodogaya Chemical Co., Ltd.), LR-147 (manufactured by Nippon Carlit Co., Ltd.) and the like; JP-A-11-15192, JP-A-3-175456, Quaternary ammonium (salt) group-containing copolymers described in, for example, Kaihei 3-243954, and sulfones described in JP-A-3-243594, JP-A-1-217464, JP-A-3-15858, and the like. Charge control resins such as acid (salt) group-containing copolymers can be used. It is preferable to use a charge control resin. Examples of commercially available products include FCA-592P (manufactured by Fujikura Kasei Co., Ltd.). The charge control agent is usually used in a proportion of 0.01 to 10 parts by weight, preferably 0.1 to 7 parts by weight, with respect to 100 parts by weight of the binder resin or the polymerizable monomer forming the binder resin. .

  Since the fatty acid ester compound used in the present invention acts as a softening agent, it is not necessary to use other softening agents. However, if desired, for the purpose of improving low-temperature fixability, the melting point is 50 to 90. A hydrocarbon compound at 0 ° C. can be further contained. Examples of such hydrocarbon compounds include polyolefin waxes such as low molecular weight polyethylene, low molecular weight polypropylene, and low molecular weight polybutylene; natural waxes such as candelilla, carnauba, rice, wood wax, and jojoba; paraffin wax, microcrystalline wax And petroleum waxes such as petrolatum; and the like, but petroleum waxes are preferred. Various commercially available products can be used as the petroleum wax. For example, PW150 (trade name: paraffin wax), PW140 (trade name: paraffin wax), PW155 (trade name: paraffin wax, manufactured by Nippon Seiki Co., Ltd.) ), HNP-11 (trade name; paraffin wax), HNP-5 (trade name; paraffin wax), Hi-Mic-1045 (trade name; microcrystalline wax), Hi-Mic-2045 (trade name; microcrystalline wax) ) And the like. The hydrocarbon compound has a melting point of 50 to 90 ° C, preferably 55 to 85 ° C, and more preferably 60 to 80 ° C. When the melting point is lower than 50 ° C., the storage stability may be lowered, and when the melting point exceeds 90 ° C., the fixing temperature is increased and the fixing property may be deteriorated. When the hydrocarbon compound is further contained, it is preferably 1 to 10 parts by weight, more preferably 2 to 8 parts by weight with respect to 100 parts by weight of the binder resin. If the content of the hydrocarbon compound is too large, the storage stability may be lowered, and if the content of the hydrocarbon compound is too small, the fixing temperature becomes high and the fixability may be deteriorated.

  As the polymerization initiator, a radical polymerization initiator is preferably used. Specifically, persulfates such as potassium persulfate and ammonium persulfate; 4,4′-azobis (4-cyanovaleric acid), 2,2′-azobis (2-amidinopropane) dihydrochloride, 2,2 '-Azobis-2-methyl-N-1,1-bis (hydroxymethyl) -2-hydroxyethylpropioamide, 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2'-azo Azo compounds such as bisisobutyronitrile and 1,1'-azobis (1-cyclohexanecarbonitrile); isobutyryl peroxide, 2,4-dichlorobenzoyl peroxide, 3,5,5'-trimethylhexanoyl Diacyl peroxides such as peroxides; bis (4-t-butylcyclohexyl) peroxydicarbonate, di-n-propylperoxydi- -Bonate, di-isopropyl peroxy di-carbonate, di-2-ethoxyethyl peroxy di-carbonate, di (2-ethyl ethyl peroxy) di-carbonate, di-methoxybutyl peroxy di-carbonate, di (3- Peroxydicarbonates such as methyl-3-methoxybutylperoxy) dicarbonate; (α, α-bis-neodecanoylperoxy) diisopropylbenzene, cumylperoxyneodecanoate, 1,1 ′, 3, 3'-tetramethylbutylperoxyneodecanoate, 1-cyclohexyl-1-methylethylperoxyneodecanoate, t-hexylperoxyneodecanoate, t-butylperoxyneodecanoate, t- Hexyl peroxypivalate, t-butyl peroxypivalate Methyl peroxide, di-t-butyl peroxide, acetyl peroxide, dicumyl peroxide, lauroyl peroxide, benzoyl peroxide, t-butyl peroxy-2-ethylhexanoate, di-isopropyl peroxide Other peroxides such as dicarbonate, di-t-butylperoxyisophthalate, and t-butylperoxyisobutyrate are exemplified. A redox initiator in which these polymerization initiators and a reducing agent are combined can also be used.

  Among these polymerization initiators, an oil-soluble radical initiator that is soluble in the polymerizable monomer is preferable, and a water-soluble initiator can be used in combination with the initiator if necessary. The use ratio of the polymerization initiator is usually 0.1 to 20 parts by weight, preferably 0.3 to 15 parts by weight, more preferably 0.5 to 10 parts by weight with respect to 100 parts by weight of the polymerizable monomer. is there. If the use ratio is too low, the polymerization rate is slow, and if it is too high, the molecular weight is low, which is not preferable. The polymerization initiator can be added to the monomer composition in advance, but it is added to the suspension after completion of the granulation process of the monomer composition in the aqueous dispersion medium in order to avoid premature polymerization. You can also The use ratio of the polymerization initiator is usually about 0.001 to 3% by weight based on the aqueous dispersion medium.

  Examples of the dispersion stabilizer used in the present invention include sulfates such as barium sulfate and calcium sulfate; carbonates such as barium carbonate, calcium carbonate and magnesium carbonate; phosphates such as calcium phosphate; metal oxides such as aluminum oxide and titanium oxide. Products; metal hydroxides such as aluminum hydroxide, magnesium hydroxide and ferric hydroxide; water-soluble polymers such as polyvinyl alcohol, methylcellulose and gelatin; anionic surfactants, nonionic surfactants, amphoteric surfactants Surfactants such as agents; and the like. Among these, metal compounds such as sulfates, carbonates, metal oxides and metal hydroxides are preferable, and colloids of slightly water-soluble metal compounds are more preferable. In particular, colloids of poorly water-soluble metal hydroxides are suitable because the particle size distribution of toner particles can be narrowed and the sharpness of images is improved.

The colloid of the hardly water-soluble metal compound is not limited by its production method, but the colloid of the hardly water-soluble metal hydroxide obtained by adjusting the pH of the aqueous solution of the water-soluble polyvalent metal compound to 7 or more, particularly water-soluble A colloid of a poorly water-soluble metal hydroxide produced by a reaction in a water phase of a functional polyvalent metal compound and an alkali metal hydroxide is preferred. The colloid of a hardly water-soluble metal compound has a number particle size distribution D ₅₀ (50% cumulative value of the number particle size distribution) of 0.5 μm or less and a D ₉₀ (90% cumulative value of the number particle size distribution) of 1 μm or less. Preferably there is. When the particle size of the colloid becomes too large, the stability of polymerization is lost, and the storage stability of the toner is lowered.

  The dispersion stabilizer is preferably used in a proportion of 0.1 to 20 parts by weight, more preferably 0.3 to 10 parts by weight with respect to 100 parts by weight of the polymerizable monomer. When this use ratio is too low, it becomes difficult to obtain sufficient polymerization stability, and polymerized aggregates are easily generated. On the other hand, if the use ratio is too high, the particle size distribution of the toner particles is broadened due to an increase in the fine particles, or the viscosity of the aqueous solution is increased and the polymerization stability is lowered.

  In order to produce colored resin particles (colored polymer particles) by suspension polymerization, first, a polymerizable monomer, a colorant, and other additive components are mixed to prepare a polymerizable monomer composition. . Next, the polymerizable monomer composition is put into an aqueous medium containing a dispersion stabilizer and stirred with a high shearing force using a high-speed stirrer or the like, and the polymerizable monomer composition is added to the aqueous medium. A minute droplet is formed.

  In forming droplets of the polymerizable monomer composition, first, primary droplets having a volume average particle diameter of about 50 to 1,000 μm are formed. In order to avoid premature polymerization, the polymerization initiator is preferably added to the aqueous dispersion medium after the primary droplet size in the aqueous medium becomes uniform. A polymerization initiator is added to and mixed with the suspension in which the primary droplets of the polymerizable monomer composition are dispersed in an aqueous dispersion medium, and the particle size of the droplets is adjusted using a high-speed rotary shearing stirrer. Stir until a small particle size close to the colored polymer particles. In this way, secondary droplets having a minute particle diameter of about 2 to 15 μm in volume average particle diameter are formed.

  The method of forming droplets is not particularly limited. For example, (inline type) emulsification disperser (trade name “Milder” manufactured by Ebara Manufacturing Co., Ltd.), high-speed emulsification / dispersion machine (product manufactured by Special Machine Industries Co., Ltd., product) This is carried out using a device capable of strong stirring such as “TK homomixer MARK type II”).

  The polymerizable monomer composition dispersed as droplets in an aqueous medium is polymerized in the presence of a polymerization initiator to produce colored polymer particles. The polymerization temperature is usually 50 ° C. or higher, preferably 60 to 95 ° C. The reaction time of the polymerization is usually 1 to 20 hours, preferably 2 to 15 hours. The aqueous dispersion containing the produced colored polymer particles is filtered, and then the colored polymer particles are recovered through the steps of washing, dehydration, and drying.

  The polymerizable monomer used to form the colored polymer particles has a glass transition temperature Tg of a polymer obtained by polymerizing it of usually 80 ° C. or lower, preferably 40 to 80 ° C., more preferably 50 to 70. It is desirable to select so that it becomes ° C. By using the polymerizable monomer alone or in combination of two or more, the glass transition temperature of the polymer to be produced can be adjusted to a desired range.

  In the case of core-shell type colored polymer particles, the glass transition temperature of the polymer constituting the shell is preferably higher than the glass transition temperature of the polymer constituting the core colored polymer particle, more preferably 5 ° C or higher. It is particularly preferable that the temperature is 10 ° C. or higher. As the polymerizable monomer for the shell, styrene, methyl methacrylate, acrylonitrile, a mixture thereof and the like capable of forming a polymer having a high glass transition temperature exceeding 80 ° C. are preferable.

  Polymerization initiators used for the polymerization of the polymerizable monomer for shell include persulfate metal salts such as potassium persulfate and ammonium persulfate; 2,2′-azobis [2-methyl-N- (2-hydroxyethyl) propion Amido], 2,2′-azobis- [2-methyl-N- [1,1-bis (hydroxymethyl) 2-hydroxyethyl] propionamide] and other azo-based initiators; Can be mentioned. The addition amount of the polymerization initiator is preferably 0.1 to 30 parts by weight, more preferably 1 to 20 parts by weight with respect to 100 parts by weight of the polymerizable monomer for shell. The polymerization temperature of the shell layer is preferably 50 ° C. or higher, more preferably 60 to 95 ° C. The polymerization reaction time is preferably 1 to 20 hours, more preferably 2 to 15 hours.

  Since the aqueous dispersion containing colored polymer particles (including core-shell type) produced by polymerization contains a dispersion stabilizer, a large number of fine particles of the dispersion stabilizer adhere to the surface of the colored polymer particles. ing. When an inorganic compound such as an inorganic hydroxide that is soluble in acid is used as the dispersion stabilizer, acid is added to the aqueous dispersion containing the produced colored polymer particles, and the dispersion stabilizer is washed with water. Dissolve in and remove. When the dispersion stabilizer is an alkali-soluble inorganic compound, the alkali is added to the aqueous dispersion containing the colored polymer particles, and the dispersion stabilizer is dissolved in water and removed.

  For example, when a colloid of a poorly water-soluble metal hydroxide such as magnesium hydroxide colloid is used as a dispersion stabilizer, an acid such as sulfuric acid is added to the aqueous dispersion to solubilize the dispersion stabilizer in water (this Is called "acid cleaning"). The pH of the aqueous dispersion is usually adjusted to 6.5 or less, preferably 2 to 6.5, more preferably 3 to 6.0 by acid washing. As the acid to be added, inorganic acids such as sulfuric acid, hydrochloric acid and nitric acid; organic acids such as formic acid and acetic acid can be used.

  The aqueous dispersion obtained in the acid washing or alkali washing step is filtered to separate the colored polymer particles. Next, the colored polymer particles separated by filtration are washed with water, and the washing water is filtered. In the water washing step, it is preferable to wash with water until the electrical conductivity of the filtrate (filtered washing water) becomes 1,000 μS / cm or less, and to filter the washing water. The water washing step may be repeated batchwise or continuously using a belt filter or the like. As a cleaning apparatus used for water cleaning, for example, it is preferable to use any one of a belt filter, a rotary filter, and a filter press, or a combination thereof. After the washing step, the wet colored polymer particles are dehydrated and dried by the dehydration step.

  The volume average particle diameter (Dv) of the toner for developing an electrostatic charge image (including core-shell type colored resin particles) of the present invention is usually 3 to 12 μm, preferably 5 to 11 μm, more preferably 6 to 10 μm. The particle size distribution represented by the ratio (Dv / Dn) of the volume average particle size (Dv) to the number average particle size (Dn) of the toner particles of the present invention is usually 1 or more and 1.7 or less, preferably It is 1.5 or less, more preferably 1.4 or less, and particularly preferably 1.3 or less. If the volume average particle diameter of the toner particles is too large, the fine line reproducibility is lowered and the resolution is liable to be lowered. When the particle size distribution of the toner particles is large, the ratio of the toner particles having a large particle size increases, and the resolution tends to decrease.

  The average circularity of the toner particles of the present invention is preferably 0.960 to 0.995, more preferably 0.970 to 0.990. If the average circularity of the toner particles is too small, due to the shape of the non-spherical toner, the fluidity of the electrostatic charge image developing toner is lowered and the fine line reproducibility is liable to be lowered. When the average circularity of the toner particles is too large, the cleaning property of the toner remaining on the photoreceptor tends to be lowered. When the average circularity of the toner particles is within the above range, the fluidity, fine line reproducibility, and cleaning properties of the electrostatic image developing toner are highly balanced.

The average circularity can be obtained by a ratio (L ₁ / L ₂ ) between the circumferential length L _{1 of the} circle equal to the projected area of the particle and the circumferential length L ₂ of the projected particle image. The average circularity is an average value of the circularity of each particle measured for toner particles having an equivalent circle diameter of 0.6 to 400 μm. The average circularity can be measured using a flow type particle image analyzer. The average circularity is an index indicating the degree of unevenness of the toner particle shape, and is 1.0 when the toner particles are completely circular, and the average circularity becomes smaller as the shape becomes more complicated.

  The amount of tetrahydrofuran (THF) extracted from the toner particles of the present invention is usually 20 to 80% by weight, preferably 25 to 70% by weight, more preferably 30 to 65% by weight. When the THF extract amount exceeds 80% by weight, storage stability and peelability are inferior, and when the THF extract amount is less than 20% by weight, the low-temperature fixability may be lowered.

  The average thickness of the shell in the core-shell type colored resin particles (core-shell type toner particles) is usually 0.001-1 μm, preferably 0.003-0.5 μm, more preferably 0.005-0.2 μm, and particularly preferably 0. 0.02-0.05 μm (20-50 nm). If the shell thickness is too large, the fixing property is lowered, and if it is too small, the storage property is lowered. When the core particle diameter and the shell thickness of the polymerized toner can be observed with an electron microscope, they can be obtained by directly measuring the size and shell thickness of particles randomly selected from the observation photograph. If it is difficult to distinguish and observe the core particle and the shell with an electron microscope, calculate the thickness of the shell from the volume average particle diameter of the core particle and the amount of polymerizable monomer used to form the shell. Can do.

  In the case of a polymerized toner, the core-shell structure is formed by using the colored resin particles as core particles, polymerizing a shell polymerizable monomer in the presence of the core particles, and forming a polymer layer on the surface of the core particles. A method of forming (shell) (in situ polymerization method) is preferred.

  The toner for developing an electrostatic charge image of the present invention has a low fixing temperature and excellent releasability, and the critical peeling temperature is preferably 190 ° C. or higher, more preferably 196 ° C. or higher, particularly preferably 200 ° C. or higher. The toner for developing an electrostatic charge image of the present invention is excellent in continuous printing characteristics after storage at a high temperature, and the aggregating property after immersion storage at 55 ° C. for 8 hours is preferably 10% by weight or less, more preferably 5% by weight. In the following, it is particularly preferably 2% by weight or less, and excellent blocking resistance at high temperature.

  When the electrostatic image developing toner of the present invention is used as a non-magnetic one-component developer, it is preferable to mix an external additive with toner particles (colored resin particles). Examples of the external additive include inorganic particles and organic resin particles that act as a fluidizing agent and an abrasive. Examples of the inorganic particles include silicon dioxide (silica), aluminum oxide (alumina), titanium oxide, zinc oxide, tin oxide, barium titanate, and strontium titanate. As organic resin particles, methacrylic acid ester polymer particles, acrylic acid ester polymer particles, styrene-methacrylic acid ester copolymer particles, styrene-acrylic acid ester copolymer particles, a core is a methacrylic acid ester copolymer, and a shell And core-shell type particles formed of a styrene polymer.

  Among these, inorganic oxide particles are preferable, and silicon dioxide is particularly preferable. The surface of the inorganic fine particles can be hydrophobized, and silicon dioxide particles that have been hydrophobized are particularly suitable. Two or more types of external additives may be used in combination. In the case of using a combination of external additives, a method of combining inorganic particles having different average particle sizes or a combination of inorganic particles and organic resin particles is preferable. . The amount of the external additive is not particularly limited, but is usually 0.1 to 6 parts by weight with respect to 100 parts by weight of the toner particles. In order to attach the external additive to the toner particles, the toner particles and the external additive are usually placed in a mixer such as a Henschel mixer and stirred.

  Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. Parts and% are based on weight unless otherwise specified. Physical properties and characteristics were measured and evaluated by the following methods.

(1) Hydroxyl value (mgKOH / g):
The hydroxyl value of the fatty acid ester compound was measured as the number of mg of potassium hydroxide required to neutralize acetic acid necessary for acetylating the free hydroxyl group contained in 1 g of the sample.

  Specifically, as an acetylating reagent, 25 g of acetic anhydride was placed in a 100 ml flask and pyridine (JIS K8777) was added up to the marked line and mixed. A 2 g sample is weighed into a 150 ml neck round bottom flask and 5 ml acetylating reagent is added. Place a small funnel on the neck of the long neck round bottom flask, submerge the bottom of the flask in a heating bath to a depth of about 1 cm and heat to 95-100 ° C. In order to prevent the temperature of the neck of the flask from rising due to the heat of the bath at this time, a cardboard disk with a round hole in it is put on the base of the neck of the flask. After 1 hour, the long round bottom flask is removed from the heating bath and cooled, and 1 ml of water is added from the funnel. Shaking the mixture generates heat and turns the anhydride into acid. To ensure the reaction is complete, the flask is once more placed in a heating bath and heated for 10 minutes. Cool to room temperature again, and wash the condensed liquid in the funnel and flask neck with 5 ml of neutral ethanol. The contents in the flask are titrated with a 0.5 mol / L potassium hydroxide-ethanol standard solution using a phenolphthalein indicator (or alkali blue 6B indicator when the mixture is strong brown). A blank test is performed in parallel with this test. The acid value of the sample is determined separately.

Hydroxyl value = [[(A−B) × 28.05 × F] / C] + acid value A: 0.5 mol / L potassium hydroxide-ethanol standard solution used in blank test (ml),
B: 0.5 mol / L potassium hydroxide-ethanol standard solution usage (ml) in this test,
F: Factor of 0.5 mol / L potassium hydroxide-ethanol standard solution,
C: Sampling amount (g).

(2) The ratio of the number of functional groups of the polyhydric alcohol and the ratio of the number of carbon atoms of the fatty acid residue in the fatty acid ester compound:
The ratio of the number of functional groups of the polyhydric alcohol and the ratio of the number of carbon atoms of the fatty acid residue in the fatty acid ester compound were determined based on the results measured by the following method.

  A 2 g sample was weighed, 6N hydrochloric acid was added to the sample, and the mixture was heated at 110 ° C. for 6 hours for hydrolysis. After hydrolysis, the sample solution was transferred to a separatory funnel and extracted by adding diethyl ether. The ether phase was directly subjected to GC-MS (gas chromatography / mass spectrometry) measurement. For the aqueous phase, water was evaporated to dryness, and then 1 ml of pyridine, 0.2 ml of hexamethyldisilazane and 0.1 ml of trimethylchlorosilane were added and heated at 100 ° C. for 20 minutes for silylation. GC-MS measurement was performed on the sample subjected to the silylation. The proportion of each component was determined from the peak area value on the chromatogram.

Measuring device: Agilent 5975 inert GC / MS system (manufactured by Agilent Technologies Inc.),
Column: HP-5 ms (30 m × 250 μmφ × 0.25 μm),
Column temperature: temperature raised from 100 ° C. to 320 ° C. (temperature raising rate 10 ° C./min, held for 15 minutes)
Carrier gas: He (1 ml / min),
Ionization method: EI (70 eV).

(3) Maximum endothermic peak temperature (° C):
The maximum endothermic peak temperature of the fatty acid ester compound was measured according to ASTM D3418-82. More specifically, using a differential scanning calorimeter, the sample was heated at a heating rate of 10 ° C./min, and the temperature showing the maximum endothermic peak of the DSC curve obtained in the process was measured. As a differential scanning calorimeter, “SSC5200” manufactured by Seiko Denshi Kogyo Co., Ltd. was used.

(4) Volume average particle size (Dv) and particle size distribution (Dv / Dn):
Particles represented by volume average particle diameter (Dv) of colored resin particles (including core-shell type colored resin particles) and a ratio (Dv / Dn) of volume average particle diameter (Dv) to number average particle diameter (Dn) The diameter distribution was measured with a multisizer (trade name, manufactured by Beckman Coulter, Inc.). The measurement with a multisizer was performed under the conditions of aperture diameter = 100 μm, medium = Isoton II, concentration = 10%, and number of measured particles = 50,000.

(5) Average circularity:
The average circularity of the colored resin particles is a value that can be measured in a water dispersion system using a flow particle image analyzer (FPIA-1000; manufactured by Sysmex Corporation). As a measurement method, 10 ml of ion-exchanged water is prepared in advance in a container, and a surfactant, preferably an alkylbenzene sulfonate, is added as a dispersant therein, and then 0.02 g of a measurement sample is added and dispersed uniformly. . As a dispersion means, an ultrasonic dispersion machine was used, and dispersion treatment was performed under conditions of 60 W and 3 minutes. The concentration of the colored resin particles at the time of measurement was adjusted to 3,000 to 10,000 particles / μl. The circularity of 1,000 to 10,000 colored resin particles was measured. Using this data, the average circularity was determined.

(6) Extraction amount of tetrahydrofuran (THF):
Tetrahydrofuran (THF) extract of the colored resin particles was measured by the following method.

  1 g of the colored resin particles is precisely weighed and placed in a Soxhlet extractor containing cylindrical filter paper (Toyo Filter Paper: No. 86R, size 28 × 100 mm), and extracted by refluxing for 6 hours using 100 ml of tetrahydrofuran (THF) as a solvent. A liquid was obtained. THF was evaporated from the extract to obtain a nonvolatile component, which was vacuum-dried at 50 ° C. for 1 hour, precisely weighed, and calculated from the following formula.

THF extraction amount (%) = S / T × 100
T: Colored resin particle sample amount (g)
S: Extracted non-volatile component amount (g)

(7) Fixing temperature:
The fixing temperature of the electrostatic charge image developing toner was measured by the following method.
A fixing test was conducted using a printer modified so that the temperature of the fixing roll portion of a commercially available non-magnetic one-component developing type printer (printing speed = 20 sheets / min) could be changed. The fixing test was performed by changing the temperature of the fixing roll of the modified printer, measuring the fixing rate of the developer at each temperature, and determining the relationship between the temperature and the fixing rate.

  The fixing rate is determined based on the ratio of the image density before and after the tape peeling operation on the black solid area of the test paper printed with the modified printer, after being left for 5 minutes or more to stabilize the temperature of the fixing roll when the temperature is changed. Calculated. The tape peeling operation means that an adhesive tape (Scotch Mending Tape 810-3-18 manufactured by Sumitomo 3M Co., Ltd.) is applied to the measurement part of the test paper, pressed and attached at a constant pressure, and then along the paper at a constant speed. It is a series of operations to peel off the adhesive tape in the direction. The image density was measured using a reflection type image density measuring machine manufactured by Gretag Macbeth.

Fixing rate (%) = (after ID / before ID) × 100
Before ID: Image density before tape peeling After ID: Image density after tape peeling

  In this fixing test, the fixing roll temperature corresponding to a fixing rate of 80% was used as the fixing temperature of the developer.

(8) Limit peeling temperature:
The critical peeling temperature of the electrostatic image developing toner was measured by the following method.
A commercially available non-magnetic one-component development type printer (Brother Kogyo Co., Ltd., HL4040CN, printing speed = 20 sheets / min) provided with a plate for separating the recording medium and the fixing roll was modified to change the temperature of the fixing roll surface. The peel test was conducted. In the peel test, the temperature of the fixing roll of the modified printer is changed from 150 ° C to 200 ° C, and a print test is performed in a normal temperature and humidity environment at a temperature of 23 ° C and a relative humidity of 50% (N / N). The temperature at which peeling failure occurred was defined as the critical peeling temperature. The peeling failure means that the recording medium is wound around the fixing roll without being peeled, or the trace of the separation plate is observed on the surface of the recording medium. The test result “200 <” indicates that no peeling failure occurred even when the temperature of the fixing roll of the modified printer was 200 ° C.

(9) Cohesiveness:
The cohesiveness of the electrostatic image developing toner was measured by the following method.
After weighing 10 g of the electrostatic charge image developing toner in a plastic container having an internal volume of 100 ml, the container was sealed and immersed in a constant temperature water bath at 55 ° C. for 8 hours. The contents of the container were sieved by vibrating with a sieve having an opening of 150 μm and an amplitude of 1.0 mm for 30 seconds. At this time, the weight of the toner remaining on the sieve was measured, and the aggregation property was evaluated by the ratio (%) of the weight to 10 g.

(10) Fine line reproducibility:
The fine line reproducibility of the electrostatic image developing toner was measured by the following method.
The fine line reproducibility test was performed using a commercially available non-magnetic one-component developing type printer (printing speed: 20 sheets / min). Put the toner to be used for the test into the developing device of the printer, set the copy paper, and leave it in a normal temperature and humidity environment at a temperature of 23 ° C. and a relative humidity of 50% (N / N) for 2 × 2 dot lines ( A line image was continuously formed with a width of about 85 μm, and the density distribution data of the line image was measured for every 500 sheets by a print evaluation system (trade name: RT2000, manufactured by YA-MA). In the evaluation, the full width at the half maximum of the density is defined as the line width, and the first line image is reproduced with a difference in the line width of 10 μm or less with reference to the line width of the first line image. The number of sheets that can maintain the line width difference of 10 μm or less was examined up to 10,000 sheets. “10000 <” in the test result indicates that the above-mentioned standard is satisfied even if 10,000 line images are printed continuously.

[Production Example 1] Fatty acid ester compound A
Fatty acid ester compound A is obtained by putting 100 parts of polyglycerin # 500 (manufactured by Sakamoto Yakuhin Kogyo Co., Ltd.) and 480 parts of behenic acid in a reaction vessel and reacting them at 240 ° C. under a catalyst and a nitrogen stream at 540 parts of a crude product. Obtained. The crude product was recrystallized with n-hexane, washed, and then dried in a vacuum dryer for 24 hours to obtain 520 parts of a polyglycerol behenate compound. The maximum endothermic peak temperature of this fatty acid ester compound was 68 ° C. Table 1 shows the results of analysis of the number of functional groups and carbon number of saturated fatty acid residues.

[Production Example 2] Fatty acid ester compound B
The fatty acid ester compound B was prepared by placing 100 parts of polyglycerin # 500 (manufactured by Sakamoto Yakuhin Kogyo Co., Ltd.) and 640 parts of behenic acid in a reaction vessel and reacting them at 240 ° C. under a catalyst and a nitrogen stream. The maximum endothermic peak temperature of this fatty acid ester compound was 71 ° C. Table 1 shows the results of analysis of the number of functional groups and carbon number of saturated fatty acid residues.

[Example 1]
1. Preparation of polymerizable monomer composition for core:
Polymeric monomer for core consisting of 77 parts of styrene and 23 parts of n-butyl acrylate, 0.25 part of polymethacrylic acid ester macromonomer (product name AA6, manufactured by Toagosei Co., Ltd.), carbon black (Mitsubishi Chemical) Co., Ltd., product name # 25B) and 7 parts of positive charge control resin (quaternary ammonium base-containing styrene / acrylic resin, manufactured by Fujikura Kasei Co., Ltd., product name FCA-592P) have stirring blades After stirring and mixing with a stirrer, the mixture was uniformly dispersed with a media-type disperser. To this mixed solution, 5 parts of fatty acid ester compound A (polyglycerin behenate ester compound) was added, mixed and dissolved to obtain a core polymerizable monomer composition.

2. Preparation of aqueous dispersion medium:
While stirring an aqueous solution in which 10 parts of magnesium chloride (water-soluble polyvalent metal salt) is dissolved in 240 parts of ion-exchanged water at 25 ° C., 5 parts of sodium hydroxide (alkali metal hydroxide) is added to 45 parts of ion-exchanged water. An aqueous solution in which was dissolved was gradually added to prepare a dispersion of magnesium hydroxide colloid (slightly water-soluble metal hydroxide colloid). When the particle size distribution of the obtained colloid was measured with a particle size distribution measuring device (manufactured by Shimadzu Corporation, product name SALD tangible distribution measuring device), D ₅₀ (50% cumulative value of the number particle size distribution) was 0. 36 μm and D ₉₀ (90% cumulative value) were 0.80 μm.

3. Granulation process:
The core polymerizable monomer composition was added to the magnesium hydroxide colloid dispersion at 45 ° C., and the mixture was stirred with a stirring device equipped with a stirring blade until the resulting coarse droplets were stabilized. Here, 4.4 parts of t-butylperoxydiethyl acetate as a polymerization initiator, 1.0 part of tetraethylthiuram disulfide (TETD) as a molecular weight regulator, and 0.5 part of divinylbenzene as a crosslinkable polymerizable monomer Then, using a high-speed shearing stirrer (manufactured by Ebara Manufacturing Co., Ltd., product name Ebara Milder), high-speed shearing stirring is performed at a rotational speed of 15,000 rpm for 5 minutes to form droplets of the polymerizable monomer composition. Granulated.

4). Preparation of polymerizable monomer for shell:
As a polymerizable monomer for shell, 1.5 parts of methyl methacrylate is used as a water-soluble polymerization initiator for shell, and 0.1 part of product name VA086 manufactured by Wako Pure Chemical Industries, Ltd. is used as 10 parts of ion-exchanged water. A dissolved solution was prepared.

5. Suspension polymerization process:
A reactor equipped with a stirring device having a stirring blade was prepared. An aqueous dispersion in which the droplets of the polymerizable monomer for the core were dispersed was charged into this reactor.

  A jacket attached to the outside of the reactor was heated until the liquid temperature of the dispersion in the reactor reached 90 ° C., thereby starting the polymerization reaction of the polymerizable monomer composition for the core. When the polymerization reaction was continued and the polymerization conversion rate reached 95%, the shell polymerizable monomer and the shell water-soluble polymerization initiator were added while maintaining the temperature in the reaction system at 90 ° C. . Further, the polymerization reaction was continued by maintaining the temperature in the reaction system at 90 ° C. for 3 hours, and then cooling water was injected into the jacket, and the temperature in the system was lowered to about 25 ° C. to stop the polymerization reaction. Through the above operation, an aqueous dispersion containing the produced core-shell type colored polymer particles was obtained in the reactor.

6). Post-processing process:
The aqueous dispersion containing the obtained colored polymer particles was stripped. First, 1 part of a non-silicone antifoaming agent (manufactured by San Nopco, product name SN deformer 180) was added to the aqueous dispersion containing the obtained colored polymer particles. Nitrogen gas was allowed to flow into the reactor, and the gas layer was replaced with nitrogen gas. Next, the aqueous dispersion containing the colored polymer particles is heated to 90 ° C., and nitrogen gas is blown into the liquid from a gas blowing pipe having a straight pipe shape for 6 hours, so that volatile substances in the liquid are obtained. It was removed. Thereafter, the aqueous dispersion containing the colored polymer particles was cooled to 25 ° C. by injecting cooling water into the jacket.

  While stirring the aqueous dispersion containing the colored polymer particles after cooling, acid washing was performed by adding sulfuric acid and neutralizing the pH of the liquid to 4.5. The wet colored polymer particles were separated from the aqueous dispersion containing the neutralized colored polymer particles by filtration. Thereafter, 500 parts of ion-exchanged water was newly added, and the colored polymer particles in a wet state were slurried again and again filtered. By repeating this slurrying and filtering three times, wet colored polymer particles were washed with water.

  The wet colored polymer particles after washing with water were dried with a vacuum dryer at a temperature of 40 ° C. for 72 hours to obtain dried core-shell colored polymer particles.

7). External addition process:
To 100 parts of colored polymer particles, 0.6 parts of hydrophobized fine particles (Cabot, product name TG820F) 0.6 parts and hydrophobized fine particles (Japan Aerosil Co., Ltd., product name NA50Y) 1 part are added, A non-magnetic one-component developer was obtained by mixing using a Henschel mixer. The volume average particle size (Dv) was 7.6 μm, the particle size distribution (Dv / Dn) was 1.19, the average circularity was 0.986, and the THF extraction amount was 55% by weight. Table 1 summarizes the test results of the obtained developer (sometimes simply referred to as toner).

[Example 2]
In Example 1, a non-magnetic one-component developer was prepared in the same manner as in Example 1 except that 5 parts of a hydrocarbon compound (trade name: HNP-11, manufactured by Nippon Seiwa Co., Ltd.) was further added as a softening agent. Obtained. The test results of the obtained toner are summarized in Table 1.

[Comparative Example 1]
A nonmagnetic one-component developer was obtained in the same manner as in Example 1 except that the softening agent was changed from the fatty acid ester compound A to the fatty acid ester compound B in Example 1. The test results of the obtained toner are summarized in Table 1.

[Comparative Example 2]
In Example 1, a nonmagnetic one-component developer was obtained in the same manner as in Example 1 except that the softening agent was changed to dipentaerythritol hexamyristate ester. The test results of the obtained toner are summarized in Table 1.

  As is clear from the comparison of the results in Table 1, 90% by weight or more of the saturated fatty acid residue in the fatty acid ester compound has 20 to 25 carbon atoms and has a specific functional group number distribution, and has a hydroxyl value. By using a fatty acid ester compound having a 10 to 20 mg KOH / g (Example 1), it has a low temperature fixability, a critical peel temperature exceeding 200 ° C., excellent peelability, and high reproducibility of fine lines. It is possible to obtain a toner for developing an electrostatic charge image having extremely small aggregation after storage.

  Further, when a hydrocarbon compound having a melting point of 50 to 90 ° C. is used in combination as a softening agent (Example 2), an electrostatic charge image developing toner having further excellent low-temperature fixability can be obtained.

  On the other hand, even if it is a fatty acid ester compound of polyglycerol, when the fatty acid ester compound of Comparative Example 1 having a hydroxyl value of less than 10 mgKOH / g is used, it cannot be said that the critical peeling temperature is sufficiently high, The toner for developing an electrostatic image is slightly inferior in peelability.

  Further, in the case of Comparative Example 2 using dipentaerythritol myristic acid ester as the aliphatic ester compound, not only the peelability is slightly inferior, but also the fine line reproducibility is deteriorated and the cohesiveness after storage at high temperature is high. An electrostatic image developing toner having poor blocking resistance can be obtained.

  The electrostatic image developing toner of the present invention is used as a developer for developing an electrostatic latent image formed on a photoreceptor in an electrophotographic (including electrostatic printing) image forming apparatus. Can do.

Claims (8)

Static resin containing colored resin particles containing a binder resin, a colorant, a charge control agent, and a fatty acid ester compound , or core-shell type colored resin particles in which a shell made of a polymer layer is further formed on the surface of the colored resin particles. In the toner for developing a charge image, the fatty acid ester compound is
(A) a fatty acid ester compound of a polyhydric alcohol mixture containing a bifunctional or higher polyhydric alcohol and a fatty acid,
(B) The content ratio of the fatty acid ester compound of a polyfunctional alcohol having 4 or less functional groups is 10% by weight or less,
(C) The content ratio of the fatty acid ester compound of the polyfunctional alcohol having 8 or more functional groups is 15% by weight or more,
(D) 90% by weight or more of the fatty acid residues have 20 to 25 carbon atoms,
(E) the hydroxyl value is 10-20 mg KOH / g, and
Containing 1 to 9 parts by weight of the fatty acid ester compound with respect to 100 parts by weight of the binder resin;
An electrostatic charge image developing toner. 2. The electrostatic image developing toner according to claim 1, wherein the fatty acid ester compound contains a fatty acid ester compound of 5 to 7 functional polyhydric alcohols in a proportion of 15% by weight or more.   The electrostatic image developing toner according to claim 1, wherein the polyhydric alcohol mixture is a polyglycerin containing a glycerin polycondensate mixture of at least a dimer to a hexamer.   The electrostatic image developing toner according to claim 3, wherein the fatty acid ester compound is a fatty acid ester compound of the polyglycerin and a saturated fatty acid having 20 to 25 carbon atoms. The charging control agent, toner according to any of claims 1 to 4, which is a charge control resin. The hydrocarbon compounds having a melting point of 50 to 90 ° C., the binder relative to 100 parts by weight of the resin, further toner according to any one of claims 1 to 5 comprising 1 to 10 parts by weight. The volume average particle diameter (Dv) is 3 to 12 μm, the ratio (Dv / Dn) of the volume average particle diameter to the number average particle diameter (Dn) is 1 to 1.7, and the average circularity is 0.960 to 0 the toner according to any one of claims 1 to 6 is .995. The toner for developing an electrostatic charge image according to any one of claims 1 to 7 , wherein a tetrahydrofuran extraction amount is 20 to 80%.