JP4314182B2 - Toner for electrophotography and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide toner which is manufactured by using a kneading and pulverizing method, gives ample image density and ensures neither fogging of non-image portions nor flying-off of the toner in a machine, even when the toner has a small-diameter particles, can form high-quality images close to those of silver salt photographs, and has high quality comparable to that of polymerized toner, and to provide a method for manufacturing the toner, in which there is no aggregation in a pulverizing/classifying step and by which stable production is achieved without problems in powder transportability. <P>SOLUTION: The toner for electrophotography is manufactured by the kneading and pulverizing method, contains a binder resin, a charge control agent, a release agent and a higher fatty acid salt, and has a number average particle diameter (Dn) of 3.0-8.0 &mu;m and a volume average particle diameter (Dv) to number average particle diameter (Dn) ratio (Dv/Dn) of 1.0-2.0. In the method for manufacturing the toner for electrophotography, at least a binder resin, a charge control agent, a release agent and a higher fatty acid salt are kneaded and pulverized, and the temperature of the resulting kneaded material is the melting point of the higher fatty acid salt or higher to (the melting point)+40&deg;C or lower. <P>COPYRIGHT: (C)2006,JPO&amp;NCIPI

Description

  The present invention relates to an electrophotographic toner produced by a kneading and pulverizing method and a method for producing the same.

  In general, an image forming apparatus such as an electrophotographic copying machine or printer forms a latent image on a photoconductive photoconductor, and forms a part of a developing device or friction with a carrier on the latent image. Insulating toner, which has obtained a triboelectric charge due to friction with the charging member, is electrostatically adhered and developed, and then the formed toner image is transferred to a transfer medium such as plain paper or film, and then heated and heated. The basic principle is to form a copy image or a print image by fixing on a transfer medium with pressure, solvent vapor or the like.

  In such an image forming apparatus, a heat roller fixing method is generally used as a method for fixing toner because of its high thermal efficiency and high speed fixing. This method fixes toner by bringing a transfer medium into contact with a heating roller in a fixing machine having a heating roller. However, in this method, a part of the toner adheres to the surface of the heating roller at the time of fixing, and there is a possibility that a so-called offset phenomenon occurs in which the toner re-transfers onto the transfer medium and stains the subsequent image. . Further, in this method, there is a possibility that a so-called winding phenomenon occurs in which the transfer medium is wound around the surface of the heating roller. Such a phenomenon is likely to occur when the releasability of the toner melted by the heating roller is not appropriate. In particular, in the case of full-color image formation, an image is usually formed by superimposing at least three toners of yellow, magenta, and cyan, so that the thickness of the toner layer is larger than in the case of monocolor image formation. The phenomenon and the wrapping phenomenon are more likely to occur, and it is necessary to further improve the toner releasability.

  Thus, as a means for preventing the occurrence of such a phenomenon, a method of introducing a release agent such as wax into the toner has been conventionally used. However, this method deteriorates the anti-fusing property of the toner, and the toner particles are fused with each other to deteriorate the heat storage property of the toner. There is a risk of becoming. In particular, in the non-magnetic one-component developing method, the toner is easily fused to the charging blade or the developing sleeve. In this method, it is not easy to uniformly and finely disperse the release agent in the binder resin at the time of toner production. When this dispersibility is low, the anti-fusing property is further deteriorated. It's easy to do. In addition, since it is not easy to select molding conditions (mixing, hot melt kneading, extrusion, cooling, etc.) for improving the dispersibility, the moldability of the toner is not sufficient. The above problems are more likely to occur as the amount of release agent introduced increases. Therefore, it is difficult to improve the fixing characteristics such as the offset phenomenon and the wrapping phenomenon without reducing the characteristics such as the anti-fusing property and the heat storage property of the toner only by introducing the release agent. The formability of the toner refers to the ease of producing a toner with good dispersion of raw materials.

  In addition, as described above, image formation by electrophotography requires that the toner has a triboelectric charge, and a charge control agent is generally used in order to secure the charge amount of the toner particles. The image density, image characteristics such as fogging of non-image areas, transferability to a transfer medium such as paper or film, and toner scattering in the machine are affected by the charge amount of individual toner particles and variations thereof. Variations in the charge amount of individual toner particles are affected by the dispersibility of the charge control agent in the binder resin.

In electrophotography, there has been a growing demand for higher image quality comparable to silver salt photographic images. In order to meet this requirement, a toner having a small particle size and a small variation in particle size is required. In the kneading and pulverization method, it is difficult to efficiently produce the toner as described above, and a polymerization method toner has been produced. However, the polymerized toner requires new technical development and capital investment, and the production cost is higher than that of the kneading and pulverizing method.
On the other hand, the kneading and pulverizing method has the merit that it is difficult to throw away that the existing technology can be applied, the existing equipment can be utilized, and the manufacturing cost can be kept low.

The following problems are raised when trying to reduce the particle size by the kneading and pulverization method.
1. The material dispersion in the toner particles becomes non-uniform.
Since the toner particle itself has a small diameter, the material dispersion in the individual toner particles becomes relatively non-uniform compared to the large particle toner.
If the material dispersion is not uniform, the characteristics of the individual toner particles will vary, which adversely affects the image. The toner generally contains a release agent and a charge control agent, but if the release agent is not uniformly dispersed, the offset resistance and the heat storage property are lowered. Further, fusion to the developing sleeve and the layer thickness regulating member, generation of carrier spent, adhesion to the photosensitive drum (filming), and the like are likely to occur.
If the dispersion of the charge control agent is non-uniform, the charge amount of individual toner particles will vary, so if you continue printing, image density will decrease, fogging, and toner scattering will easily occur. Become.
2. The smaller the particle size, the greater the physical stress received by the toner, and the toner tends to pulverize in the image forming process.
As the pulverization of the toner proceeds, the dispersion of the material in the toner particles becomes more non-uniform, and the above problem 1 becomes more prominent. Therefore, since the toner remaining on the surface of the photoreceptor is collected and reused, it is not suitable for a toner recycling system that receives more physical stress.
3. When the particle size is small, the fluidity is deteriorated and the powder is easily agglomerated, the powder transportability is deteriorated, the stable production in the pulverization / classification process becomes difficult, and the production efficiency (yield) is lowered.

JP-A-8-76420 JP 60-247250 A JP-A-61-112159 JP 57-63550 A JP-A-56-101150

  The object of the present invention is to produce a kneading and pulverizing method, even if the particle size is small, the mechanical strength is strong and the pulverization does not proceed in the image forming process. Excellent fusibility and heat storage stability, uniform charging characteristics, sufficient image density, no fogging of non-image areas, no toner scattering, and high-quality image formation close to silver salt photography , Providing a high-quality toner comparable to the polymerization toner, and a production method capable of stable production with high production efficiency (yield) without aggregation in the pulverization / classification process and no problem in powder transportability That is.

  As a result of intensive studies on improving dispersion of materials used in a small particle size electrophotographic toner produced by a kneading and pulverizing method, the present inventor can solve the above problems by including a higher fatty acid salt. As a result, the present invention has been completed.

That is, the present invention can solve the above-mentioned problems by the following technical configuration.
(1) Manufactured by a kneading pulverization method, contains a binder resin, a charge control agent, a release agent, and a higher fatty acid salt, and the release agent is 0.5 to 20 with respect to 100 parts by weight of the binder resin. 3 parts by weight and 3 to 10 parts by weight of the higher fatty acid salt, the kneaded material temperature during production is not lower than the melting point of the higher fatty acid salt and not higher than the melting point + 40 ° C., and the number average particle diameter (Dn) is 3.0. An electrophotographic toner, characterized by having a ratio (DV / Dn) of 1.0 to 2.0 and a ratio of a volume average particle diameter (Dv) to a number average particle diameter (Dn) of about 8.0 to about 8.0 μm.
(2) The toner is characterized in that the softening point (Tst) of the toner is 100 to 155 ° C. and the difference (Tsr−Tst) from the softening point (Tsr) of the binder resin is 20 to 60 ° C. The toner for electrophotography as described in 1).
(3) The toner for electrophotography as described in (1) or (2) above, wherein the polyester resin in the binder resin is 50 to 100% by weight.
(4) The electrophotographic toner according to any one of (1) to (3), wherein the at least one type of release agent is a hydrocarbon wax having no polar group.
(5) The electrophotographic toner according to any one of (1) to (4), wherein the melting point of at least one type of release agent is 90 to 180 ° C.
(6) The electrophotographic toner according to any one of (1) to (5), wherein the release agent has a dispersed particle size of 1.0 μm or less.
(7) The toner for electrophotography as described in any one of (1) to (6) above, wherein the higher fatty acid has 10 to 42 carbon atoms.
(8) The toner for electrophotography according to any one of (1) to (7), wherein the higher fatty acid salt is at least one selected from a zinc salt, a magnesium salt, and an aluminum salt.
(9) A method for producing a toner in which at least a binder resin, a charge control agent, a release agent, and a higher fatty acid salt are mixed, kneaded, extruded, pulverized, and classified, and the toner is added to 100 parts by weight of the binder resin. the release agent is 0.5 to 20 parts by weight and the high-grade fatty acid salt is from 3 to 10 parts by weight, the temperature of the kneaded product, higher fatty acid salt melting above, and the melting point + 40 ℃ Ri der less, number-average particle size (Dn) of the 3.0～8.0Myuemu, and the ratio (DV / Dn) is 1.0 to 2.0 der Rukoto a volume average particle diameter and (Dv) to a number average particle size (Dn) of A method for producing an electrophotographic toner, which is characterized.

The present invention is produced by a kneading and pulverization method, and even with a small particle size, the material dispersion is uniform in each toner particle, excellent in anti-offset property, anti-fusing property and heat storage property, and uniform in charging characteristics. Therefore, it is possible to provide a high-quality electrophotographic toner with sufficient image density, no fogging of non-image areas, no toner scattering, and high-quality image formation close to silver salt photography. . Further, it is possible to provide an electrophotographic toner that has high mechanical strength and does not pulverize in the image forming process and maintains high image quality even in continuous use.
In addition, according to the method for producing an electrophotographic toner of the present invention, there is provided a production method capable of stable production with high production efficiency (yield) without agglomeration in the pulverization / classification step and no problem in powder transportability. Can do.

<Binder resin>
Examples of the binder resin in the present invention include polyester resins, styrene- (meth) acrylic acid copolymer resins, styrene resins, (meth) acrylic resins, olefin resins (for example, α such as polyethylene and polypropylene). -Olefin resins, etc.), vinyl resins (eg, polyvinyl chloride, polyvinylidene chloride, etc.), polyamide resins, polyether resins, urethane resins, epoxy resins, polyphenylene oxide resins, terpene phenol resins, polylactic acid Examples thereof include resins, hydrogenated rosins, cyclized rubbers, cycloolefin copolymer resins, and thermoplastic elastomers. These can be used alone or in combination of two or more. Among these, polyester resins and styrene- (meth) acrylic acid copolymer resins are preferable from the viewpoint that the image quality characteristics, durability, productivity, and the like of the toner can be satisfied in a balanced manner. Here, (meth) acrylic acid means acrylic acid and / or methacrylic acid.

  The binder resin used in the toner for forming a high image quality melts instantaneously at the time of toner fixing to form a smooth image surface from the viewpoint of image smoothness and gloss, and the toner particle interface does not exist. Therefore, it is necessary to use a relatively low molecular weight resin that melts rapidly at low temperatures. However, when the molecular weight of the resin is lowered, the mechanical strength is likely to be lowered, and accordingly, there is a problem of reduction in production efficiency due to over-pulverization in the toner pulverization process, or due to destruction of toner particles in the developing machine. There are problems such as a decrease in toner durability, a decrease in toner adhesion strength (fixing strength) to a transfer medium, and a deterioration in heat storage properties due to a decrease in glass transition temperature.

Therefore, as a binder resin for a toner for forming a high image quality, it has an appropriate mechanical strength even when the molecular weight is lowered, is suitable for a small particle size, and has characteristics such as a low melt viscosity and a high glass transition temperature. Polyester resins are preferred. When other resins are used in combination, it is preferable that the binder resin contains 50% by weight or more of the polyester resin in order to exhibit the above effects.
On the other hand, the styrene- (meth) acrylic acid copolymer resin is likely to have a decrease in mechanical strength as the molecular weight is lowered, and as a result, the production efficiency of the toner is lowered, the durability is lowered or fixed during use. Problems such as a decrease in intensity and a reduction in image quality are likely to occur. However, polymerization toners are also widely used in high-quality toners with a small particle size.

Examples of the polyester resin include those obtained by condensation polymerization of alcohol and carboxylic acid.
Examples of the alcohol include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,3-butylene glycol, 1,4-butanediol, neopentyl glycol, 1,4 Diols such as butenediol; 1,4-bis (hydroxymethyl) cyclohexane; etherified bisphenols such as bisphenol A, hydrogenated bisphenol A, polyoxyethylenated bisphenol A, polyoxypropylenated bisphenol A; Valent alcohol monomer. These alcohols may be used alone or in combination of two or more.

  Examples of the carboxylic acid include maleic acid, fumaric acid, mesaconic acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid, cyclohexanedicarboxylic acid, succinic acid, adipic acid, sebacic acid, malonic acid, Examples thereof include anhydrides of these acids, dimers of lower alkyl esters and linolenic acid, and other divalent organic acid monomers. These carboxylic acids may be used alone or in combination of two or more.

  The polyester resin may be not only a polymer based on only a bifunctional monomer but also a polymer containing a component based on a trifunctional or higher polyfunctional monomer. Examples of trihydric or higher polyhydric alcohol monomers that are polyfunctional monomers include sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, Tripentaerythritol, sucrose, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, tri Mention may be made of methylolpropane, 1,3,5-trihydroxymethylbenzene and other trihydric or higher polyhydric alcohol monomers.

Examples of the trivalent or higher polyvalent carboxylic acid monomer include 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 1,2,4-cyclohexanetricarboxylic acid, 7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylene Carboxypropane, tetra (methylenecarboxyl) methane, 1,2,7,8-octanetetracarboxylic acid, empole trimer acid, these acid anhydrides, other trivalent or higher polyvalent carboxylic acid monomers Can do.
The amount of the trifunctional or higher polyfunctional monomer is 10 to 90 mol, preferably 20 to 80 mol, more preferably 30 to 80 mol, based on 100 mol of the total of the alcohol and carboxylic acid components. Can be selected as appropriate.

Styrene- (meth) acrylic acid copolymer resin can be composed of a copolymer of styrene monomer units and (meth) acrylic acid monomer units, and other monomer units as required. May be contained.
Examples of the styrene monomer include styrene, alkyl styrene (vinyl toluene such as o-methyl styrene, m-methyl styrene, p-methyl styrene, vinyl xylene, pt-butyl styrene, etc.) or derivatives thereof, alkoxy Examples thereof include styrene (such as p-methoxystyrene) or derivatives thereof, p-phenylstyrene or derivatives thereof, halostyrene (such as o-chlorostyrene, m-chlorostyrene, p-chlorostyrene), or derivatives thereof. These monomers can be used alone or in combination of two or more. Examples of the derivatives include alkyl-substituted products, alkylidene-substituted products, alkoxy-substituted products, acyl-substituted products, halogen-substituted products, nitro-substituted products, amino-substituted products, hydroxy-substituted products, and carboxyl-substituted products.

Examples of the (meth) acrylic acid monomer include (meth) acrylic acid, alkyl (meth) acrylate [methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, ( Butyl (meth) acrylate, t-butyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, dodecyl (meth) acrylate, stearyl (meth) acrylate, (meth) acrylic acid (Meth) acrylic acid C _1-20 alkyl ester such as behenyl, (meth) acrylic acid C _4-10 cycloalkyl ester], (meth) acrylic acid aryl ester, (meth) acrylic acid C _7-12 aralkyl ester, ( Hydroxyalkyl (meth) acrylate [hydroxyethyl (meth) acrylate, hydroxymeth (meth) acrylate Pills, etc.], (meth) acrylate, glycidyl (meth) dialkylaminoalkyl [dimethylaminoethyl (meth) acrylate acrylate, (meth) acrylic acid diethylaminoethyl], di C _1-4 alkyl phosphate (meth ) Acrylate and the like. These monomers can be used alone or in combination of two or more.

  Other monomers include vinyl monomers (vinyl acetate, vinyl propionate, vinyl benzoate, etc.), unsaturated olefin monomers (ethylene, propylene, etc.), diene monomers (isoprene, butadiene, etc.) ), Unsaturated dicarboxylic acids (fumaric acid, maleic acid, itaconic acid, citraconic acid and their anhydrides), (meth) acrylonitrile monomers, (meth) acrylamide monomers, ketones (vinyl methyl ketone) And vinyl hexyl ketone) and ethers (vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether, etc.). These other monomers are preferably contained in 30 parts by weight or less in 100 parts by weight of the styrene- (meth) acrylic acid copolymer resin. In order to adjust the acid value and the charging characteristics, it is preferable to use a monomer containing a carboxyl group or acid anhydride group such as maleic anhydride and fumaric acid.

As a preferable styrene- (meth) acrylic acid copolymer resin formed by the monomer, a polymer mainly composed of a styrene monomer unit and a (meth) acrylic acid monomer unit, for example, , Styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-acrylic acid-n-butyl copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene _Examples thereof include styrene- (meth) acrylic acid C _1-18 alkyl ester copolymers such as methacrylic acid-n-butyl copolymer, and multipolymers such as styrene-acrylic acid ester-methacrylic acid ester.

The content of the binder resin is preferably 40 to 95 parts by weight in the electrophotographic toner (100 parts by weight), and 80 to 95 parts by weight for the nonmagnetic toner.
The softening point of the binder resin of the present invention is preferably 130 to 210 ° C, more preferably 140 to 200 ° C, and further preferably 150 to 195 ° C.
When the softening point of the binder resin is lower than 130 ° C., the softening point of the toner tends to be excessively lowered, and offset resistance is lowered. When the temperature exceeds 210 ° C., the softening point of the toner also increases, so that the melt viscosity increases and the fixing strength tends to decrease.

The method for measuring the softening point of the binder resin and toner is as follows.
The temperature in the middle of the moving distance from the start to the end of the plunger descent when measured with the following measuring machine and measurement conditions is defined as the softening point.
Measuring instrument: Shimadzu Corporation Koka flow tester CFT-500
Measurement condition;
Plunger: 1 cm ²
Die diameter: 1mm
Die length: 1mm
Load: 20KgF
Preheating temperature: 50-80 ° C
Preheating time: 300 sec
Temperature increase rate: 6 ° C / min

  The glass transition temperature (Tg) of the binder resin of the present invention is preferably 50 to 85 ° C, more preferably 55 to 80 ° C, and further preferably 60 to 75 ° C. If the temperature is less than 50 ° C., the heat storage stability of the toner is lowered.

In the present invention, the glass transition temperature (Tg) of the binder resin is defined as follows. About 5 mg of a sample is placed in an aluminum cell, placed on a differential scanning calorimeter (DSC) (trade name: SCC6200, manufactured by Seiko Instruments Inc.), and 50 ml of N ₂ gas is blown in one minute while JIS K DSC measurement is performed according to 7121-1987, and the midpoint glass transition temperature (Tmg ° C.) described in 9.3 of the JIS is determined from the observed DSC temperature rise curve.
As a specific measuring method, first, the sample is heated at a rate of 10 ° C. per minute between 20 and 120 ° C. and held at 120 ° C. for 10 minutes. Next, the temperature is lowered to 120 to 20 ° C. at a rate of 10 ° C. per minute and held at 20 ° C. for 10 minutes. Next, the temperature is raised a second time under the above conditions, and the DSC temperature rise curve (Tmg ° C.) observed at that time is defined as Tg in the present invention.

  The weight average molecular weight (Mw) of the binder resin of the present invention is preferably 30,000 to 200,000, more preferably 50,000 to 180,000. The number average molecular weight (Mn) is preferably from 2,000 to 15,000, more preferably from 3,000 to 12,000. When Mw and Mn exceed the upper limit, the melt viscosity increases and the low-temperature fixability and fixing strength decrease. When the Mw and Mn are less than the lower limit, the mechanical strength decreases, and the production efficiency due to excessive grinding in the toner grinding process. Decrease in durability, deterioration in durability due to breakage in the developing process, fusion resistance, and heat storage stability.

The above Mn and Mw are values obtained by GPC (gel permeation chromatography) method, and the measurement method is as follows.
A GPC measuring device (manufactured by JASCO Corporation, trade names: JASCO GULLIVER SERIES AS-950 type, PU-980 type) was used, and tetrahydrofuran (THF) was allowed to flow at a flow rate of 1 ml per minute at a temperature of 40 ° C. Measurement is performed by injecting 30 mg of a 2 g / dl THF solution as a sample weight. In the measurement, the measurement conditions are selected such that the molecular weight distribution of the sample falls within a range in which the logarithm of the molecular weight and the number of counts of a calibration curve prepared by several monodisperse polystyrene standard samples are linear. In this measurement, the reliability of the measurement is determined based on the measurement conditions included in the range in which the logarithm of the molecular weight and the count number are linear in the calibration curve prepared with the NBS706 polystyrene standard sample performed under the above-described measurement conditions. select. In this measurement, the reliability of the measurement is that of the NBS706 polystyrene standard sample (Mw = 28.8 × 10 ⁴ , Mn = 13.7 × 10 ⁴ , Mw / Mn = 2.11) performed under the above measurement conditions. It can be confirmed that Mw / Mn is 2.11 ± 0.10.

<Charge control agent>
The electrophotographic toner of the present invention needs to contain a charge control agent.
Examples of positively chargeable charge control agents include modified products of nigrosine and fatty acid metal salts; quaternary ammonium salts such as tributylbenzylammonium-1-hydroxy-4-naphthosulfonate and tetrabutylammonium tetrafluoroborate Diorganotin oxides such as dibutyltin oxide, dioctyltin oxide and dicyclohexyltin oxide; diorganotin borates such as dibutyltin borate, dioctyltin borate and dicyclohexyltin borate; pyrididium salts, azines, triphenylmethane compounds, cationic functional groups And low molecular weight polymers having These positively chargeable charge control agents may be used alone or in combination of two or more. Among these positively chargeable charge control agents, nigrosine compounds and quaternary ammonium salts are preferably used.

Examples of the negatively chargeable charge control agent include organic metal compounds such as acetylacetone metal complexes, azo metal complexes, naphthoic acid or salicylic acid metal complexes or salts, chelate compounds, and low molecular weight polymers having an anionic functional group. Is mentioned. These negatively chargeable charge control agents can be used alone or in combination of two or more.
Moreover, positive chargeability and negative chargeability can also be used together as needed.
The content of the charge control agent is usually in the range of 0.1 to 5 parts by weight, preferably 0.5 to 4 parts by weight, more preferably 1 to 4 parts by weight with respect to 100 parts by weight of the binder resin. It is. Also,
For color toners, it is preferable to use a colorless or light charge control agent.

<Release agent>
The toner for electrophotography of the present invention needs to contain a release agent. As release agents, polyolefin waxes such as polyethylene wax, polypropylene wax and modified polyethylene wax; synthetic waxes such as Fischer-Tropsch wax; petroleum waxes such as paraffin wax and microcrystalline wax; animal waxes such as beeswax and whale wax Plant waxes such as carnauba wax, candelilla wax and rice wax; hardened oils such as hardened castor oil; and mineral waxes such as montan wax, ozokerite and ceresin. These release agents can be used alone or in combination of two or more.
As the release agent, a hydrocarbon wax having no functional group is preferable in terms of offset resistance. Examples of the wax include polyolefin waxes such as polyethylene wax and polypropylene wax; synthetic waxes such as Fischer-Tropsch wax; petroleum waxes such as paraffin wax and microcrystalline wax. Generally, when there is no functional group, the dispersibility in the binder resin is poor, and this tendency is strong particularly when the binder resin is a polyester resin, but in the present invention, a higher fatty acid salt is used. Can prevent this problem.

  The content of the release agent is usually about 0.5 to 20 parts by weight with respect to 100 parts by weight of the binder resin, but in the present invention, it is preferably 0.5 to 15 parts by weight, more preferably 1.0-10 weight part, More preferably, it is 1.0-5 weight part. When the content of the release agent exceeds 15 parts by weight, dispersion in the binder resin is deteriorated, and there is a possibility that the anti-fusing property, the heat storage property and the moldability of the toner are deteriorated. On the other hand, when the content of the release agent is less than 0.5 parts by weight, a winding phenomenon is likely to occur, and fixing properties such as offset resistance may be deteriorated. In the present invention, since the dispersion diameter of the release agent can be controlled to be small by the action of the higher fatty acid salt, the amount of the release agent used can be reduced, and the fusing resistance, heat storage property and toner moldability are further improved. Excellent toners can be obtained. In particular, in the toner for a non-magnetic one-component developing system, it is easy to achieve both fixing characteristics and anti-fusing characteristics. It is also suitable for oilless fixing systems.

  At least one of the release agents in the present invention preferably has a melting point measured by a differential scanning calorimeter of 90 to 180 ° C., more preferably 100 to 160 ° C. When the melting point of all the release agents is less than 90 ° C., there is a possibility that the anti-fusing property and heat storage stability of the toner may be lowered, and when it exceeds 180 ° C., the fixing strength may be deteriorated.

The melting point of the release agent is measured as follows according to ASTM D3418-82.
About 5 mg of a sample is weighed and placed in an aluminum cell and placed on a differential scanning calorimeter (DSC) (trade name: SCC-6200, manufactured by Seiko Instruments Inc.), and 50 ml of N ₂ gas is supplied per minute. Infuse. The temperature is raised between 0 ° C. and 200 ° C. at a rate of 10 ° C. per minute, held at 200 ° C. for 10 minutes, then lowered from 200 ° C. to 0 ° C. at a rate of 10 ° C. per minute, The temperature is raised for the second time under the above conditions, and the temperature at the top of the maximum endothermic peak at that time is taken as the melting point.

  The dispersion diameter of the release agent in the toner particles is preferably 0.3 to 1.0 μm. If it exceeds 1.0 μm, the release agent tends to be detached from the toner particles, and if it is less than 0.3 μm, the fine dispersion is excessively advanced and the release effect may be insufficient. However, in the present invention, there is an advantage that even if the fine dispersion is excessively advanced, the offset resistance is not deteriorated so much because the higher fatty acid salt has releasability.

The method for measuring the dispersion diameter is as follows.
After extruding the kneaded product, a section having a cross section perpendicular to the extrusion direction of the cooled and rolled sheet-shaped resin composition is prepared using a microtome (MT6000, manufactured by DuPont). This section is observed at a magnification of 400 times using an optical microscope (BHS-SW, manufactured by Olympus Corporation) and photographed. The release agent particles visually observed in this photographic image are taken in as computer image data, and the release agent particles observed visually using the attached powder image analysis software (Macview, manufactured by Mountech Co., Ltd.). The average major axis (A) and the average minor axis (B) were calculated for the cross section, and the average of A and B was taken as the dispersion diameter.

<Higher fatty acid salt>
The higher fatty acid salt used in the present invention is a metal salt or an ammonium salt, and a saturated or unsaturated fatty acid salt having 10 to 42 carbon atoms. 14-35 are preferable and, as for carbon number of a higher fatty acid, 16-20 are more preferable. Examples of saturated fatty acids include capric acid, undecylic acid, lauric acid, tridecylic acid, myristic acid, pentadecylic acid, palmitic acid, heptadecylic acid, stearic acid, nonadecanoic acid, arachidic acid, behenic acid, lignoceric acid, serotic acid, heptacosane Examples of unsaturated fatty acids such as acid, montanic acid, mellicic acid, and laccellic acid include undecylenic acid, oleic acid, elaidic acid, celetic acid, erucic acid, brassic acid, linoleic acid, linolenic acid, arachidonic acid, stearol Examples thereof include acid and ricinoleic acid. Moreover, as a saturated or unsaturated fatty acid, dibasic acids, such as sebacic acid and dodecanedioic acid, can also be used. Of the above higher fatty acids, stearic acid, palmitic acid and oleic acid are preferred, and stearic acid is particularly preferred.

  Examples of metals that form salts with the above higher fatty acids include alkaline earth metals such as calcium, magnesium, and barium, zinc, cadmium, aluminum, lead, cobalt, iron, copper, nickel, chromium, manganese, mercury, and cerium. Examples thereof include monovalent metals such as valent metals, sodium, potassium, and lithium. Of these, zinc, magnesium and aluminum are preferable, and zinc is particularly preferable.

The higher fatty acid salt has the effect of lowering the melt viscosity of the binder resin and is considered to be excellent in wettability with other materials, and the materials used, particularly the dispersion of the charge control agent and the release agent, as well as the dispersion Improve the adhesion between the particles and the binder resin. If the release agent is well dispersed, a toner having excellent offset resistance, fusing resistance, and thermal stability can be obtained, and the content of the release agent can be reduced. Therefore, the content of the release agent can be further reduced. In addition, when the charge control agent is well dispersed, the image density is sufficient, non-image areas are not fogged, and toner is not scattered in the machine even when a large number of continuous prints are made.
Further, when the adhesion between the dispersed particles and the binder resin is good, the particles dispersed in the toner particles are difficult to be detached from the toner particles.
Content of the said higher fatty acid salt is 0.5-10 weight part with respect to 100 weight part of binder resin, Preferably it is 0.5-7 weight part, More preferably, it is 1-5 weight part. If the content of the higher fatty acid salt exceeds 10 parts by weight, the higher fatty acid salt tends to be detached from the toner particles, and if it is less than 0.5 parts by weight, the effect of lowering the melt viscosity and the effect of improving dispersion and adhesion are not sufficiently exhibited. . Two or more higher fatty acid salts may be used as appropriate.
The melting point of the higher fatty acid salt is preferably 100 to 190 ° C, more preferably 110 to 180 ° C, and further preferably 120 to 170 ° C. When the melting point is less than 100 ° C., the solution viscosity is low, re-aggregation tends to occur, and the dispersion effect decreases. If it exceeds 180 ° C., the selection of kneading temperature conditions is limited.

<Colorant>
Examples of the colorant in the present invention include black pigments for black toners and magenta pigments, cyan pigments, yellow pigments and the like for color toners.
Carbon black is usually used as the black pigment. The number average particle size, oil absorption, PH, etc. of carbon black are not particularly limited. Examples of commercially available products include those manufactured by Cabot Corporation of the United States, trade names: REGAL 400, 660, 330, 300, 550R, SRF-S, STERLING SO, V, NS, R; Columbia Carbon Japan Product name: Raven H20, MT-P, 410, 420, 430, 450, 500, 760, 780, 1000, 1035, 1060, 1080; manufactured by Mitsubishi Chemical Corporation, product names: # 5B, # 10B , # 40, # 2400B, MA-100 and the like. These carbon blacks can be used alone or in combination of two or more.

The content of carbon black is preferably 0.1 to 20 parts by weight, more preferably 1 to 10 parts by weight, still more preferably 1 to 5 parts by weight, particularly preferably 1 to 1 part by weight with respect to 100 parts by weight of the binder resin. 3 parts by weight. If the carbon black content is too small, the image density is lowered, and if it is too much, the image quality is liable to be lowered, and the toner moldability is also lowered. As a black pigment, black magnetic powder such as iron oxide and ferrite can be used in addition to carbon black.
In the present invention, the content of carbon black can be increased by the dispersing action of the higher fatty acid salt.

  Examples of the magenta pigment include C.I. I. Pigment Red 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 21, 22, 23, 30, 31, 32, 37, 38, 39, 40, 41, 48, 49, 50, 51, 52, 53, 54, 55, 57, 58, 60, 63, 64, 68, 81, 83, 87, 88, 89, 90, 112, 114, 122, 123, 163, 202, 206, 207, 209; I. Pigment violet 19; C.I. I. Bat red 1, 2, 10, 13, 15, 23, 29, 35, etc. are mentioned. These magenta pigments can be used alone or in combination of two or more.

Examples of cyan pigments include C.I. I. Pigment blue 2, 3, 15, 16, 17; I. Bat Blue 6; C.I. I. Acid Blue 45 etc. are mentioned. These cyan pigments can be used alone or in combination of two or more.
Examples of yellow pigments include C.I. I. Pigment Yellow 1, 2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 14, 15, 16, 17, 23, 65, 73, 74, 83, 93, 94, 97, 155, 180 etc. are mentioned. These yellow pigments can be used alone or in combination of two or more.

From the viewpoint of color mixing and color reproducibility, the color pigment of the full color toner is C.I. I. Pigment Red 57 and 122 are C.I. I. Pigment Blue 15 is C.I. I. Pigment Yellow 17, 93, 155, and 180 can be preferably used.
The content of the color pigment is usually 1 to 20 parts by weight, preferably 3 to 10 parts by weight, more preferably 4 to 9 parts by weight, and particularly preferably 4 to 100 parts by weight of the binder resin. 5 to 8 parts by weight. When the content of the color pigment is too smaller than the above range, the image density is lowered, and when it is too much, the charging stability is deteriorated and the image quality is liable to be lowered. It is also disadvantageous in terms of cost. Further, as a color pigment, a so-called master batch in which a color pigment is dispersed at a high concentration in a resin that can be a binder resin in advance is often used. The necessity is small, and it can be contained more than usual.

<Other ingredients>
(Magnetic powder)
The electrophotographic toner of the present invention may further contain magnetic powder as required. Examples of magnetic powder include metals such as cobalt, iron, and nickel; alloys of aluminum, copper, iron, nickel, magnesium, tin, zinc, gold, silver, selenium, titanium, tungsten, zirconium, and other metals; aluminum oxide And metal oxides such as iron oxide and nickel oxide; ferrite, magnetite and the like.
The content of the magnetic powder is usually 1 to 70 parts by weight, preferably 5 to 50 parts by weight, in the electrophotographic toner (100 parts by weight). As magnetic powder, that whose average particle diameter is 0.01-3 micrometers can be used conveniently.
The present invention improves the dispersion of the magnetic powder by the dispersing action of the higher fatty acid salt, and therefore can be preferably applied to a magnetic toner.

(Other additives)
The electrophotographic toner of the present invention further contains various additives as necessary, for example, stabilizers (for example, ultraviolet absorbers, antioxidants, thermal stabilizers, etc.), flame retardants, antifogging agents, dispersants, Nucleating agent, plasticizer (phthalate ester, fatty acid plasticizer, phosphoric acid plasticizer, etc.), polymer antistatic agent, low molecular antistatic agent, compatibilizer, conductive agent, filler, fluidity improver, etc. It may contain.

(Inorganic fine particles)
In the electrophotographic toner of the present invention, it is preferable that inorganic fine particles adhere to the surface in order to improve fluidity, charge stability, cleaning properties and storage stability. Examples of the inorganic fine particles include silica, alumina, talc, clay, calcium carbonate, magnesium carbonate, titanium oxide, zinc oxide, silicon carbide, zirconia, carbon black powder, and magnetic powder. These inorganic fine particles may be used alone or in combination of two or more. Of these inorganic fine particles, silica can be particularly preferably used.
Silica is not particularly limited, such as an average particle diameter, a BET specific surface area, and a surface treatment, and can be appropriately selected depending on the application. Among them, those having a BET specific surface area in the range of 50 to 400 m ² / g are preferable, and surface-treated hydrophobic silica is more preferable.

(Resin fine powder)
In the electrophotographic toner of the present invention, in addition to the inorganic powder particles, resin fine powders such as polytetrafluoroethylene resin powder and polyvinylidene fluoride resin may be adhered to the surface.
Further, fatty acid salts such as magnesium stearate and zinc stearate and silicone oil may be adhered.
The ratio of adding the inorganic fine particles or resin fine powder can be appropriately selected from the range of 0.01 to 8 parts by weight, preferably 0.1 to 5 parts by weight, more preferably 100 parts by weight of the electrophotographic toner. 0.1 to 4 parts by weight, particularly preferably 0.3 to 3 parts by weight. If the added ratio is less than 0.01 parts by weight, there is little effect on the fluidity and charging stability of the toner, and it is difficult to form a uniform image. If it exceeds 8 parts by weight, inorganic fine particles are easily released, It adheres to the photoconductor and the developing machine member and degrades the image quality.

<Toner for electrophotography>
The use of the electrophotographic toner of the present invention is not particularly limited depending on the development method, and can be used in a non-magnetic one-component development method, a magnetic one-component development method, a two-component development method, and other development methods. In the magnetic one-component development system, magnetic powder is mixed with a binder resin and used as a magnetic toner. In the two-component development method, toner is mixed with a carrier and used. In recent years, a non-magnetic one-component development method is preferred from the viewpoint of simplicity of the apparatus and cost. The electrophotographic toner of the present invention is suitable for a non-magnetic one-component system because the toner is difficult to fuse to each member of a developing machine such as a charging blade and a developing sleeve. It is also suitable for a toner recycling system.

  As the carrier in the two-component development system, for example, nickel, cobalt, iron oxide, ferrite, iron, glass beads and the like can be used. These carriers may be used alone or in combination of two or more. The carrier preferably has an average particle size of 20 to 150 μm. In addition, the surface of the carrier may be coated with a coating agent such as a fluorine resin, an acrylic resin, or a silicone resin. Further, a magnetic material dispersed in a binder resin may be used.

  The electrophotographic toner of the present invention may be a monocolor toner or a full color toner. In the monocolor toner, carbon black or the like can be used as a colorant, and in the full color toner, a colorant. As mentioned above, the color pigment can be used.

<Toner production method>
The toner particle production method of the present invention comprises a binder resin, a charge control agent, a release agent, a higher fatty acid salt, a colorant, and other components as necessary, and the mixture is hot-melt kneaded and extruded. This is a kneading and pulverizing method in which after the product is obtained, the extruded product is pulverized and classified to obtain toner composed of toner particles having a desired particle size and particle shape.

Examples of the hot melt kneading method include various methods such as a method using a twin screw extruder, a method using a Banbury mixer, a method using a pressure roller, and a method using a pressure kneader. From the viewpoint of moldability (dispersibility of materials) and versatility, a method using a twin screw extruder is preferred. The extruded product is obtained by melting and kneading the mixture with a twin screw extruder and extruding from a die (die) at the tip of the twin screw extruder. The kneading temperature of the twin screw extruder is 70 to 250 ° C, preferably 70 to 200 ° C, more preferably about 90 to 200 ° C.
In the production method of the present invention, the temperature at the extrusion port of the kneaded product needs to be not lower than the melting point of the higher fatty acid salt and not higher than the melting point + 40 ° C., preferably + 35 ° C. or lower.
When the temperature of the kneaded product is lower than the melting point of the higher fatty acid salt, the action of finely dispersing the charge control agent and the release agent is not exerted. When the temperature exceeds 40 ° C., the higher fatty acid salt becomes too low in viscosity and re-aggregates. The dispersion effect is reduced.
Examples of the pulverization method include a pulverization method using an apparatus such as a hammer mill, a cutter mill, or a jet mill. Moreover, as a classification method, the method by an airflow classifier like a dry centrifugal classifier is usually mentioned.

(Toner particle size)
The number average particle diameter (Dn) of the toner thus obtained is 3.0 to 8.0 μm, preferably 4.0 to 7.0 μm. If the number average particle diameter exceeds 8.0 μm, it is difficult to achieve high image quality, and if it is less than 3.0 μm, the powder fluidity is remarkably deteriorated. The volume average particle size / number average particle size (Dv / Dn) needs to be 1.0 to 2.0, preferably 1.0 to 1.8, and more preferably 1.0 to 2.0. 1.6. If it exceeds 2.0, it will be difficult to achieve high image quality. The number average particle diameter (Dn) and the volume average particle diameter (Dv) are a number 50% diameter and a volume 50% diameter measured using a particle size distribution measuring device (Multisizer II, manufactured by Beckman Coulter, Inc.).

(Toner softening point)
The softening point (Tst) of the electrophotographic toner of the present invention is preferably from 100 to 155 ° C, more preferably from 120 to 150 ° C, further preferably from 125 to 150 ° C. If it is less than 100 ° C., the offset resistance cannot be exhibited. If it exceeds 155 ° C., the melt viscosity is too high and the fixing strength cannot be obtained.
The difference (Tsr-Tst) between the softening point (Tsr) of the binder resin and the toner softening point is preferably 20 to 60 ° C, more preferably 25 to 50 ° C, and more preferably 30 to 50 ° C. More preferably. If the temperature is lower than 20 ° C., the material is not sufficiently dispersed in the binder resin. If the temperature is higher than 60 ° C., the softening point of the toner is excessively lowered to cause a problem in offset resistance, or the softening point of the binder resin is low. High and hinders the kneading process.

  Further, it is preferable that the inorganic fine particles and the resin fine powder are adhered to the surface of the toner particles by stirring using a stirrer such as a turbine stirrer, a Henschel mixer, or a super mixer.

Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.
The material components used in Examples and Comparative Examples, and toner evaluation methods are shown below.

[Material components]
<Binder resin>
Resin A: Polyester resin (softening point: 170 ° C .: Tg: 67 ° C., Mw: 120,000, Mn: 8,000).
Resin B: Polyester resin (softening point: 184 ° C .: Tg: 70 ° C., Mw: 93,000, Mn: 9,200).
Resin C: Polyester resin (softening point: 165 ° C .: Tg: 64 ° C., Mw: 150,000, Mn: 5,000)
<Charge control agent>
CCA-A: Chrome azo-based negatively chargeable charge control agent (manufactured by Orient Chemical Industries, trade name: Bontron S-34).
CCA-B: Nigrosine-based positively chargeable charge control agent (Orient Chemical Industries, trade name: Nigrosine N-4).
<Release agent>
WAX-A: Polypropylene wax (manufactured by Sanyo Chemical Industries, trade name: Viscol 550P, melting point: 139 ° C.).
WAX-B: Polyethylene wax (manufactured by Hoechst, trade name: PE-130, melting point: 130 ° C.).
<Higher fatty acid metal salt>
Higher fatty acid salt A: zinc stearate (melting point: 125 ° C.)
Higher fatty acid salt B: magnesium stearate (melting point: 140 ° C.)
Higher fatty acid salt C: Aluminum stearate (melting point: 160 ° C.)
<Colorant>
Colorant: Carbon black (trade name: Regal 550R, manufactured by Cabot Corporation)

[Toner Evaluation Method]
<Softening point>
It was measured by the method described in [0025] above.

<Fixing characteristics>
4 parts by weight of toner and 96 parts by weight of non-coated ferrite carrier (FL-1020, manufactured by Powdertech Co., Ltd.) were mixed to prepare a two-component developer. Next, using this developer, a commercially available copier (negatively chargeable toners (Examples 1 to 3, Comparative Examples 1 to 4) are SF-2022 manufactured by Sharp Corporation), and positively charged toner (Examples). 4-5 and Comparative Examples 5-7) SF-2035 (manufactured by Sharp Corporation) produced strip-shaped unfixed images 3 cm long and 6 cm wide on A4 transfer paper. The toner adhesion amount on the transfer paper was adjusted to about 2.0 mg / cm ² depending on the toner concentration, the surface potential of the photoreceptor, the development potential, the exposure amount, the transfer conditions, and the like. Subsequently, an oilless type fixing machine in which a heat fixing roller having a surface layer formed of polytetrafluoroethylene and a pressure fixing roller having a surface layer formed of silicone rubber are rotated in pairs, and a roller pressure is set to 1 kgf / cm ^2, adjusted to the roller speed is 125 mm / sec, the surface temperature of the heat fixing roller stepwise increased at intervals of 10 ° C. between 120 to 240 ° C., the unfixed image at each surface temperature The toner image of the transfer paper having a toner image was fixed. After fixing, observation was made as to whether or not toner smear occurred in the margin, and the non-offset temperature range (° C.) was determined with the temperature region where the smear did not occur as a non-offset temperature region. The non-offset temperature range is preferably 80 ° C. or higher.

<Thin wire reproducibility>
A line image of 200 lines / inch was observed with a 50 × magnifier.
A: The line image is less than 5 thin.
A: The line image is thin (scratch) at 6 to 10 places.
Δ: The line image is thin (scratch) at 11 to 15 places.
X: The line image is thin (scratch) at 16 or more locations.
If the fine line reproducibility is inferior, it is also inferior to the reproduction of high-quality photographic quality.

<Fusion resistance>
Only the developing machine of the nonmagnetic one-component printer JX-9210 manufactured by Sharp Corporation was taken out, and an external stirring device capable of rotating the developing sleeve was produced. The external stirrer was filled with toner, stirred for 1 hour, and visually confirmed whether or not streaks due to toner fusion were observed on the developing sleeve.
A: No streaks due to toner fusion are observed.
○: Slight streaks due to toner fusion were observed, but there was no practical problem.
X: Streaks due to toner fusion are severe and unusable for practical use.

[Production efficiency]
The yield in the pulverization / classification process was evaluated. If the toner powder transportability is inferior, the toner adheres to the inner wall surface of the apparatus, and the yield decreases.
Yield = (toner output / input amount) × 100%

[Production of toner]
<Examples 1-5, Comparative Examples 1-7>
As raw materials for the toner, binder resin, charge control agent, release agent, higher fatty acid salt, and colorant were used in the ratios shown in Tables 1 and 2.
Each of the above materials is heated, melt-kneaded using a twin-screw kneading extruder (manufactured by Ikegai Co., Ltd.) under conditions such that the outlet temperature of the kneaded material is as shown in Tables 1 and 2, and a sheet-shaped resin composition is obtained. It was. Next, the sheet-shaped resin composition was pulverized with a jet mill and then classified with a dry air classifier to obtain toner particles having physical properties described in Tables 1 and 2. To 100 parts by weight of the obtained toner particles, 0.7 part by weight of hydrophobic silica is added and mixed with stirring by a Henschel mixer for 5 minutes to obtain an externally added toner in which hydrophobic silica is added to the toner particle surface. It was. The obtained toner was evaluated for non-offset temperature range, fine line reproducibility and anti-fusing property in an environment of 22 ° C. and 58% RH, and the production efficiency was evaluated by the yield of the pulverization / classification process. 1 and Table 2.
The hydrophobic silica used was R972 (manufactured by Nippon Aerosil Co., Ltd.) for negatively chargeable toners (Examples 1 to 3, Comparative Examples 1 to 4), and positively charged toners (Examples 4 to 5 and Comparative Examples). 5-7) is HVK-2150 (Hoechst).

  As is apparent from Tables 1 and 2, the toners of Examples 1 to 5 were excellent in the non-offset temperature range, fine line reproducibility, fusing resistance, and production efficiency (yield).

On the other hand, since the toner of Comparative Example 1 did not contain a higher fatty acid salt, the toner had a high softening point, the melt viscosity did not decrease during fixing, and the non-offset temperature range was narrow. Moreover, due to the poor dispersion of the wax, the anti-fusing property was inferior and the production efficiency was inferior. Furthermore, fine line reproducibility was inferior due to poor dispersion of the charge control agent.
Since the toner of Comparative Example 2 has a large number average particle diameter, the fine line reproducibility was inferior and the image quality was not improved.
Since the toner of Comparative Example 3 has a small number average particle diameter, it is inferior in fluidity as a powder and thus inferior in fine line reproducibility, and inferior in production efficiency because it adheres to the inner wall surface of the pulverization / classification process. It was a thing.
Since the toner of Comparative Example 4 has a large Dv / Dn, a large number of large-diameter particles are present, resulting in poor fine line reproducibility.
In the toner of Comparative Example 5, since the kneaded product had a high kneading port temperature, the higher fatty acid salt became too low in viscosity and re-aggregated. Therefore, the dispersion effect was reduced, resulting in poor dispersion of the release agent. As a result, the anti-fusing property and the production efficiency were lowered, and the dispersion of the charge control agent was deteriorated, so that the fine line reproducibility was deteriorated.
The toner of Comparative Example 6 had a kneaded product having an extrusion port temperature higher than that of Comparative Example 5. Therefore, the dispersion of the release agent and the charge control agent was further worse than that of Comparative Example 5, and the fusing resistance and fine line reproducibility were further improved. Declined. In addition, production efficiency has declined.
In the toner of Comparative Example 7, since the extrusion port temperature of the kneaded product was lower than the melting point of the higher fatty acid salt, the release agent and the charge control agent were poorly dispersed, the non-offset temperature range was narrow, the fine line reproducibility, and the anti-fusing property Inferior in productivity and production efficiency.

  The electrophotographic toner of the present invention can reproduce a photographic tone high image quality and can be suitably used in any developing system, but is particularly suitable as a toner used in a non-magnetic one-component developing system and an oilless fixing system.

Claims (9)

Manufactured by a kneading and pulverizing method, containing a binder resin, a charge control agent, a release agent, and a higher fatty acid salt, and 0.5 to 20 parts by weight of the release agent with respect to 100 parts by weight of the binder resin; The higher fatty acid salt is 3 to 10 parts by weight, the kneaded material temperature during production is not lower than the melting point of the higher fatty acid salt and not higher than the melting point + 40 ° C., and the number average particle diameter (Dn) is 3.0 to 8. An electrophotographic toner having a volume average particle diameter (Dv) and a number average particle diameter (Dn) ratio (DV / Dn) of 1.0 to 2.0.   The softening point (Tst) of the toner is 100 to 155 ° C, and the difference (Tsr-Tst) from the softening point (Tsr) of the binder resin is 20 to 60 ° C. Toner for electrophotography.   The toner for electrophotography according to claim 1 or 2, wherein the polyester resin is 50 to 100% by weight in the binder resin.   4. The electrophotographic toner according to claim 1, wherein the at least one type of release agent is a hydrocarbon wax having no polar group.   The electrophotographic toner according to any one of claims 1 to 4, wherein the melting point of at least one type of release agent is 90 to 180 ° C.   6. The toner for electrophotography according to claim 1, wherein the particle size of the release agent is 1.0 μm or less.   The toner for electrophotography according to any one of claims 1 to 6, wherein the higher fatty acid has 10 to 42 carbon atoms.   The electrophotographic toner according to claim 1, wherein the higher fatty acid salt is at least one selected from a zinc salt, a magnesium salt, and an aluminum salt. A method for producing a toner comprising mixing, kneading, extruding, pulverizing, and classifying at least a binder resin, a charge control agent, a release agent, and a higher fatty acid salt, and the release agent with respect to 100 parts by weight of the binder resin There is a 0.5 to 20 parts by weight and the high-grade fatty acid salt is 3 to 10 parts by weight, the temperature of the kneaded product, higher fatty acid salt melting above, and the melting point + 40 ℃ Ri der less, number-average particle diameter (Dn ) is 3.0～8.0Myuemu, and the ratio of the volume average particle diameter and (Dv) to a number average particle diameter (Dn) (DV / Dn) is characterized 1.0-2.0 der Rukoto A method for producing an electrophotographic toner.