JP2005325266A - Binder resin, toner for electrophotography and its manufacturing method, developer for electrophotography and image forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a binder resin capable of realizing a toner for electrophotography excellent in electrostatic charging stability, a toner for electrophotography excellent in electrostatic charging stability and its manufacturing method, a developer for electrophotography, and an image forming method. <P>SOLUTION: The binder resin containing 1-10,000 ppm of a rare earth element, particularly a crystalline polyester resin containing 1-10,000 ppm of a rare earth element is provided. The toner for electrophotography containing it and its manufacturing method, the developer for electrophotography, and the image forming method are also provided. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a binder resin used for an electrophotographic toner that can be used in an electrophotographic apparatus using an electrophotographic process such as a copying machine, a printer, and a facsimile machine, an electrophotographic toner using the same, a manufacturing method thereof, and The present invention relates to an electrophotographic developer and an image forming method.

  Many methods are known as electrophotographic methods (for example, refer to Patent Document 1). In general, a latent image is electrically formed by various means on the surface of a photoreceptor (latent image holding body) using a photoconductive substance, and the formed latent image is developed with toner. After the image is formed, the toner image on the surface of the photoconductor is transferred to the surface of the transfer medium such as paper with or without the intermediate transfer body, and the transferred image is heated, pressed, heated and pressed, or solvent A fixed image is formed through a plurality of steps of fixing with steam or the like. The toner remaining on the surface of the photoreceptor is cleaned by various methods as necessary, and is again subjected to the above-described plurality of steps.

As a fixing technique for fixing the transferred image transferred on the surface of the transfer target, a hot roll fixing in which the transfer target with the toner image transferred is inserted and fixed between a pair of rolls consisting of a heating roll and a pressure roll. The law is common. In addition, as the same type of technology, one in which one or both of the rolls are replaced with a belt is also known. These techniques can obtain a fast and robust fixed image compared to other fixing methods, have high energy efficiency, and are less harmful to the environment due to volatilization of solvents and the like.
On the other hand, in order to reduce the amount of consumed energy of copying machines and printers, a technique for fixing toner with lower energy is desired, and there is a strong demand for toner for electrophotography that can be fixed at a lower temperature.

  As means for lowering the toner fixing temperature, means for lowering the glass transition point of the toner resin (binder resin) is used. Examples of the binder resin for toner include polyester. In particular, crystalline polyester resin is used for electrophotography. Polyester contains acid groups and hydroxyl groups and is easily affected by the environment, particularly humidity. As attempts to improve the chargeability, proposals for lowering the acid value of the resin (for example, see Patent Document 2) and proposals using an organic fluorine compound (for example, see Patent Document 3 or 4) are shown. In either case, the chargeability is not sufficient.

Further, as a toner using a rare earth element compound, a combination of an α-Si photoreceptor, a one-component magnetic toner, a rare earth element fluoride compound, and a rare earth oxide compound is disclosed (for example, Patent Document 5 or 6). reference.). Further, a toner using a binder resin and a toner using cerium oxide and a rare earth element compound as external additives are disclosed (for example, see Patent Document 7 or 8).
Each of the examples uses a technique of externally adding a rare earth element compound on the surface of the toner, and these purposes are used to improve cleaning defects.

On the other hand, recently, an energy-saving production method has been proposed with a view to reducing environmental burden (CO ₂ gas reduction). In the field of electrophotography (see, for example, Patent Document 9), from the viewpoint of energy saving, there is a demand from the market to reduce toner production energy and use energy of printers or copiers. .
With regard to toner production methods, suspension polymerization methods and melt suspension methods have been developed from conventional hot melt kneading, pulverization, and classification methods, and from the viewpoint of production energy, progress has been made in the direction of reduction. Yes.
However, the energy required for manufacturing the resin for toner has not been sufficiently reduced.

In particular, polyester resins that can lower the fixing energy currently consume a great deal of energy for production compared to vinyl polymer resins, and the total energy consumed by resin production energy and toner production method. Will be enormous.
For example, in the production of toner resin, conventionally, a tin-based catalyst such as dibutyltin oxide and a titanium-based catalyst such as titanium oxide are generally used. In order to produce a high molecular weight polymer compound necessary for imparting viscoelasticity and durability to the toner using these, reaction conditions under high vacuum (150 ° C. or higher) and low vacuum are required. .
Japanese Patent Publication No.42-23910 JP-A-62-291668 Japanese Patent Laid-Open No. 11-24306 JP 2003-107802 A Japanese Patent Laid-Open No. 2002-311769 JP 2002-311639 A JP 2002-314487 A JP 2001-265057 A JP-A-10-26842

  An object of the present invention is to provide a binder resin that can be used for an electrophotographic toner and that can realize an electrophotographic toner having excellent charging stability. Furthermore, the present invention uses the electrophotographic toner containing the binder resin of the present invention, a method for producing the same, the electrophotographic developer containing the electrophotographic toner of the present invention, and the electrophotographic toner of the present invention. An object is to provide an image forming method.

That is, the present invention
<1> A binder resin containing 1 to 10,000 ppm of rare earth elements.

  <2> The binder resin according to <1>, comprising a polyester resin containing 1 to 10,000 ppm of a rare earth element.

  <3> The binder resin according to <1>, wherein the rare earth element is Sc, Y, Yb, or Sm.

  <4> The binder resin according to <1>, synthesized using a catalyst represented by the following formula (1).

X (OSO ₂ CF ₃ ) ₃ formula (1)

(In formula (1), X represents Sc, Y, Yb or Sm.)

  <5> The binder resin according to <1>, synthesized using a catalyst represented by the following formula (2).

X (N (OSO ₂ CF ₃ ) ₂ ) ₃ formula (2)

(In the formula (2), X represents Sc, Y, Yb or Sm.)

  <6> An electrophotographic toner containing at least the binder resin according to any one of <1> to <5> and a colorant.

  <7> An emulsification step of emulsifying the binder resin according to any one of <1> to <5> to prepare binder resin emulsified particles, and an aggregate including at least the binder resin emulsified particles. An electrophotographic toner production method comprising an aggregation step to be formed and a fusion step for fusing the aggregates.

  <8> An electrophotographic developer containing the electrophotographic toner according to <6> and a carrier.

  <9> A latent image forming step for forming an electrostatic latent image on the surface of the latent image holding member, and a developer carried on the developer carrying member, and the electrostatic latent image formed on the surface of the latent image holding member is A developing step for developing and forming a toner image, a transferring step for transferring the toner image formed on the surface of the latent image holding member to the surface of the transfer target, and a heat fixing of the toner image transferred to the surface of the transfer target The image forming method includes a fixing step, wherein the developer is the electrophotographic toner according to <6> or the electrophotographic developer according to <8>.

  According to the present invention, it is possible to provide a binder resin capable of realizing an electrophotographic toner excellent in charging stability. Further, according to the present invention, an electrophotographic toner having excellent charging stability, a method for producing the same, an electrophotographic developer containing the electrophotographic toner of the present invention, and image formation using the electrophotographic toner of the present invention. A method can be provided.

The binder resin, electrophotographic toner and method for producing the same, electrophotographic developer and image forming method of the present invention will be described in detail below.
<Binder resin>
The binder resin of the present invention contains 1 to 10,000 ppm of rare earth elements. The binder resin of the present invention is suitably used as a binder resin contained in an electrophotographic toner. In the present invention, ppm refers to parts per million by mass.

In the binder resin of the present invention, if the rare earth element content is 1 ppm or less, the toner is not charged when the binder resin of the present invention is used for an electrophotographic toner, and thus a clear image cannot be obtained. There is.
Further, when the rare earth element content is 10,000 ppm or more, the charge of the toner is increased, so that fog or background stains may occur.

  The rare earth element content in the binder resin of the present invention is preferably 5 to 5000 ppm.

The kind of rare earth element contained in the binder resin of the present invention is not particularly limited, but is preferably Sc, Y, Yb or Sm, and more preferably Sc.
In addition, the kind of rare earth element contained in the binder resin of the present invention may be one kind alone or two or more kinds. When two or more kinds of rare earth elements are contained in the binder resin of the present invention, the total amount of the two or more kinds of rare earth elements is used as the rare earth element content.

As a method of incorporating a rare earth element in the binder resin of the present invention, a method of adding a rare earth element compound when the binder resin of the present invention is synthesized or when an electrophotographic toner is produced by the method described later. Can be mentioned. Rare earth element compounds include oxides, hydroxides, oxoacid salts, acetates, oxalates, thiocyanates, cyanides, borides, silicides, sulfates, chlorides, fluorides, and other inorganic salts. Can be mentioned.
When the rare earth element compound is added when synthesizing the binder resin of the present invention, a method of using a catalyst containing a rare earth element as the rare earth element compound and leaving the catalyst in the binder resin is preferable.
Alternatively, the binder resin can be heated and melted, a rare earth element-containing compound is added to the binder resin, and the rare earth element is contained in the binder resin by stirring.

  The binder resin of the present invention is not particularly limited as long as it contains 1 to 10,000 ppm of a rare earth element, but is preferably a polyester resin, and more preferably a crystalline polyester resin. By using crystalline polyester, fixability to paper is improved, and further, toner blocking resistance, image storage stability, and fixability at low temperature are improved.

  The binder resin of the present invention is preferably synthesized using a catalyst represented by the following formula (1).

X (OSO ₂ CF ₃ ) ₃ formula (1)

  In formula (1), X represents Sc, Y, Yb or Sm.

  Moreover, it is also preferable that the binder resin of this invention is what was synthesize | combined using the catalyst represented by following formula (2).

X (N (OSO ₂ CF ₃ ) ₂ ) ₃ formula (2)

  In formula (2), X represents Sc, Y, Yb or Sm.

By performing the synthesis using the catalyst represented by the formula (1) or the formula (2), a rare earth element can be contained in the binder resin.
The catalyst represented by Formula (1) or Formula (2) is suitably used for polyester resin synthesis.
Hereinafter, the synthesis of the polyester resin using the catalyst represented by the formula (1) or the formula (2) will be described.
The amount of the catalyst used is preferably 0.01% by mass to 10% by mass with respect to the resin to be produced. If it is less than this, the progress of the polycondensation ester reaction will be slow, and if it is more than this, the charge amount will be adversely affected.
The catalyst can be polycondensed at a lower temperature than conventionally used tin-based catalysts and titanium-based catalysts. Specifically, the conventional catalyst required a reaction temperature of 180 ° C. or higher to obtain a polyester resin having a weight average molecular weight Mw = 20000 in the same time, whereas the resin of the present invention was 150 ° C. It can be obtained as follows.
By using the catalyst represented by Formula (1) or Formula (2), the energy required for the production of the polyester resin can be reduced.

  The method for producing the polyester resin is not particularly limited, and can be produced by a general polyester polymerization method in which an acid component and an alcohol component are reacted. For example, direct polycondensation, transesterification method, etc. Produced separately for different types. The polymerization reaction type is not particularly limited such as solution polymerization and bulk polymerization, but bulk polymerization is suitable. Furthermore, in the case of bulk polymerization, it is important to reduce the reaction pressure to an appropriate level in order to promote dehydration. In the present invention, when the pressure is lowered to 40 mmHg or less, the reaction proceeds well.

  The molar ratio (acid component / alcohol component) when the acid component reacts with the alcohol component varies depending on the reaction conditions and the like, and cannot be generally stated, but is usually about 1/1. In the catalyst, the optimum temperature for the polymerization is such that the higher the reaction temperature, the higher the progress of the ester reaction. In the present invention, the optimum temperature is 120 ° C. or less.

  The polyester resin is synthesized from an acid (dicarboxylic acid) component and an alcohol (diol) component. In the following description, in the polyester resin, the component that was an acid component before the synthesis of the polyester resin is referred to as “acid-derived component”, and the component that was the alcohol component before the synthesis of the polyester resin is referred to as “alcohol. "Derived component".

As the binder resin of the present invention, a crystalline polyester resin is preferable. When the polyester resin is not crystalline, that is, is amorphous, it may not be possible to maintain toner blocking resistance and image storage stability while ensuring good low-temperature fixability.
In the present invention, the “crystallinity” of the “crystalline polyester resin” means that it has a clear endothermic peak in the differential scanning calorimetry (DSC), not a stepwise endothermic change. Further, the endothermic peak may show a peak having a width of 40 to 50 ° C. when the toner is used. In the case of a polymer obtained by copolymerizing other components with the crystalline polyester main chain, if the other components are 50% by mass or less, this copolymer is also called crystalline polyester.

-Acid-derived components-
Examples of the acid for forming the acid-derived constituent component include various dicarboxylic acids, and the acid-derived constituent component in the crystalline polyester resin is preferably an aromatic dicarboxylic acid or an aliphatic dicarboxylic acid, and particularly an aliphatic dicarboxylic acid. An acid is desirable, and a linear carboxylic acid is particularly desirable.

  Examples of the aliphatic dicarboxylic acid include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelic acid, sebacic acid, 1,9-nonanedicarboxylic acid, and 1,10-decanedicarboxylic acid. 1,11-undecanedicarboxylic acid, 1,12-dodecanedicarboxylic acid, 1,13-tridecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid, 1,16-hexadecanedicarboxylic acid, 1,18-octadecanedicarboxylic acid, Or lower alkyl esters and acid anhydrides thereof, but are not limited thereto. Among these, considering availability, sebacic acid and 1,10-decanedicarboxylic acid are preferable.

Examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, 4,4′-biphenyldicarboxylic acid, etc. Among them, terephthalic acid is an easily available, low melting point polymer. It is preferable in terms of easy formation.
As the acid-derived constituent component, in addition to the aforementioned aliphatic dicarboxylic acid-derived constituent component and aromatic dicarboxylic acid-derived constituent component, a dicarboxylic acid-derived constituent component having a double bond, a dicarboxylic acid-derived constituent component having a sulfonic acid group, etc. Are preferably included.

  The component derived from a dicarboxylic acid having a double bond is derived from a lower alkyl ester or acid anhydride of a dicarboxylic acid having a double bond, in addition to a component derived from a dicarboxylic acid having a double bond. Components are also included. The dicarboxylic acid-derived component having a sulfonic acid group is derived from a lower alkyl ester or acid anhydride of a dicarboxylic acid having a sulfonic acid group, in addition to a component derived from a dicarboxylic acid having a sulfonic acid group. Components are also included.

The dicarboxylic acid having a double bond can be suitably used to prevent hot offset at the time of fixing since the entire resin can be crosslinked using the double bond. Examples of such dicarboxylic acids include, but are not limited to, fumaric acid, maleic acid, 3-hexenedioic acid, and 3-octenedioic acid. Moreover, these lower alkyl esters, acid anhydrides, etc. are also mentioned. Among these, fumaric acid, maleic acid and the like are preferable in terms of cost.
The dicarboxylic acid having a sulfonic acid group is effective in that it can favorably disperse a coloring material such as a pigment. Further, when the entire resin is emulsified or suspended in water to produce fine particles, if a sulfonic acid group is present, it can be emulsified or suspended without using a surfactant as described later. Examples of such a dicarboxylic acid having a sulfone group include, but are not limited to, 2-sulfoterephthalic acid sodium salt, 5-sulfoisophthalic acid sodium salt, and sulfosuccinic acid sodium salt. Moreover, these lower alkyl esters, acid anhydrides, etc. are also mentioned. Among these, 5-sulfoisophthalic acid sodium salt is preferable in terms of cost.

Total acid-derived components of acid-derived components other than aliphatic dicarboxylic acid-derived components and aromatic dicarboxylic acid-derived components (dicarboxylic acid-derived components having double bonds and dicarboxylic acid-derived components having sulfonic acid groups) As content in a component, 1-20 structural mol% is preferable and 2-10 structural mol% is more preferable.
When the content is less than 1 constituent mol%, pigment dispersion may not be good, the emulsified particle diameter may be large, and adjustment of the toner diameter by aggregation may be difficult.
On the other hand, if it exceeds 20 component mol%, the crystallinity of the polyester resin is lowered, the melting point is lowered, the image storage stability is deteriorated, or the emulsion particle size is too small to dissolve in water, and no latex is produced. Sometimes.
In the present specification, “constituent mol%” refers to a percentage when each constituent component (acid-derived constituent component or alcohol-derived constituent component) in the polyester resin is defined as one unit (mol).

-Alcohol-derived components-
As alcohol for becoming a component derived from alcohol, aliphatic diol is preferable, and linear aliphatic diol having 7 to 20 chain carbon atoms is more preferable. When the aliphatic diol is branched, the crystallinity of the polyester resin is lowered and the melting point is lowered, so that the toner blocking resistance, the image storage stability, and the low-temperature fixability may be deteriorated.
When the chain carbon number is less than 7, when polycondensation with an aromatic dicarboxylic acid, the melting point becomes high and low-temperature fixing may be difficult. It tends to be difficult to obtain. The chain carbon number is more preferably 14 or less.
Further, when a polyester is obtained by condensation polymerization with an aromatic dicarboxylic acid, the chain carbon number is preferably an odd number. When the chain carbon number is an odd number, the melting point of the polyester resin is lower than when the chain carbon number is an even number, and the melting point tends to be a value within the numerical range described later.

  Specific examples of the aliphatic diol include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, Examples thereof include, but are not limited to, 1,18-octadecanediol, 1,20-eicosanediol, and the like. Among these, 1,8-octanediol, 1,9-nonanediol, and 1,10-decanediol are preferable in view of availability, and 1,9-nonanediol is preferable in terms of a low melting point.

The alcohol-derived constituent component has an aliphatic diol-derived constituent component content of 80 constituent mol% or more, and includes other components as necessary. As the alcohol-derived constituent component, the content of the aliphatic diol-derived constituent component is preferably 90 constituent mol% or more.
When the content of the aliphatic diol-derived constituent component is less than 80 mol%, the crystallinity of the polyester resin is lowered and the melting point is lowered, so that toner blocking resistance, image storage stability, and low-temperature fixability deteriorate. May end up. Other components included as necessary include diol-derived components having double bonds and diol-derived components having sulfonic acid groups.

  Examples of the diol having a double bond include 2-butene-1,4-diol, 3-butene-1,6-diol, 4-butene-1,8-diol, and the like. Examples of the diol having a sulfonic acid group include 1,4-dihydroxy-2-sulfonic acid benzene sodium salt, 1,3-dihydroxymethyl-5-sulfonic acid benzene sodium salt, and 2-sulfo-1,4-butanediol sodium. Examples include salts.

When adding an alcohol-derived component other than the aliphatic diol-derived component (a diol-derived component having a double bond and a diol-derived component having a sulfonic acid group), the content of these alcohol-derived components is 1 -20 constituent mol% is preferable and 2-10 constituent mol% is more preferable.
When the content of the alcohol-derived constituent component other than the aliphatic diol-derived constituent component is less than 1 constituent mol%, the pigment dispersion is not good, the emulsified particle size is large, and it is difficult to adjust the toner diameter by aggregation. On the other hand, if it exceeds 20 component mol%, the crystallinity of the polyester resin is lowered, the melting point is lowered, the storability of the image is deteriorated, or the emulsified particle size is too small to dissolve in water. Latex may not occur.

  As melting | fusing point of the said polyester resin, it is preferable that it is 60-120 degreeC, and it is more preferable that it is 70-100 degreeC. When the melting point is less than 60 ° C., powder aggregation tends to occur and the stability of a fixed image may be deteriorated. On the other hand, when it exceeds 120 ° C., the characteristics deteriorate.

  As melting | fusing point of the said amorphous polyester resin, it is preferable that it is 50-100 degreeC, and it is more preferable that it is 60-80 degreeC. When the melting point is less than 50 ° C., powder aggregation tends to occur and the storability of the fixed image may be deteriorated. On the other hand, when the melting point exceeds 100 ° C., the characteristics deteriorate.

  Furthermore, a biodegradable polyester resin may be used as the polyester resin.

<Toner for electrophotography>
The electrophotographic toner of the present invention contains at least the binder resin of the present invention and a colorant, and may contain other components such as a release agent and a charge control agent as necessary. Good.
-Colorant-
There is no restriction | limiting in particular as a coloring agent used for this invention, A well-known coloring agent is mentioned, It can select suitably according to the objective. As the colorant, one type of pigment may be used alone, or two or more types of pigments of the same system may be mixed and used. Two or more different types of pigments may be mixed and used.

  Specific examples of the colorant include carbon black such as furnace black, channel black, acetylene black, and thermal black, inorganic pigments such as bengara, aniline black, bitumen, titanium oxide, and magnetic powder, fast yellow, and monoazo. Yellow, disazo yellow, pyrazolone red, chelate red, brilliant carmine (3B, 6B, etc.), azo pigments such as para brown, phthalocyanine pigments such as copper phthalocyanine, metal-free phthalocyanine, flavantron yellow, dibromoanthrone orange, perylene red, quinacridone Examples thereof include condensed polycyclic pigments such as red and dioxazine violet.

  Chrome Yellow, Hansa Yellow, Benzidine Yellow, Slen Yellow, Quinoline Yellow, Permanent Orange GTR, Pyrazolone Orange, Vulcan Orange, Watch Young Red, Permanent Red, Dupont Oil Red, Resol Red, Rhodamine B Lake, Lake Red C, Rose Various pigments such as Bengal, Aniline Blue, Ultramarine Blue, Calco Oil Blue, Methylene Blue Chloride, Phthalocyanine Blue, Phthalocyanine Green, Malachite Green Oxalate, Para Brown; Acridine, Xanthene, Azo, Benzoquinone, Azine, Anthraquinone, dioxazine, thiazine, azomethine, indigo, thioindigo, phthalocyanine, aniline black , Polymethine dyes, triphenylmethane dyes, diphenylmethane dyes, thiazole type, various dyes such as xanthene; and the like. You may mix black pigments, such as carbon black, and dye to such an extent that transparency is not reduced to these colorants. Moreover, a disperse dye, an oil-soluble dye, etc. are mentioned.

The content of the colorant in the electrophotographic toner of the present invention is preferably 1 to 30 parts by mass with respect to 100 parts by mass of the binder resin of the present invention, but does not impair the smoothness of the image surface after fixing. In such a numerical range, it is preferable to have as many as possible.
Increasing the content of the colorant is advantageous in that the thickness of the image can be reduced when an image having the same density is obtained, which is effective in preventing offset. In addition, by appropriately selecting the type of the colorant, each color toner such as yellow toner, magenta toner, cyan toner, and black toner can be obtained.

-Mold release agent-
Typical examples of the release agent include low molecular weight polyethylene, low molecular weight polypropylene, Fischer tropic wax, montan wax, carnauba wax, rice wax, and candelilla wax.

-Charge control agent-
A charge control agent may be added to the toner of the present invention as necessary. As the charge control agent, known ones can be used. For example, quaternary ammonium salts such as cetylpyridyl chloride, P-51 and P-53 (manufactured by Orient Chemical Industries), S-44 and S-34. Azo-based metal complex compounds (produced by Orient Chemical Industries), salicylic acid metal complex compounds such as E-84 (produced by Orient Chemical Industries), resin types containing polar groups, dyes composed of complexes such as aluminum, iron, chromium, tri Charge control agents such as phenylmethane pigments, metal oxide fine particles, or metal oxide fine particles surface-treated with various coupling agents can be used.
When the toner is manufactured by a wet manufacturing method, it is preferable to use a material that is difficult to dissolve in water in terms of controlling ionic strength and reducing wastewater contamination. The toner in the present invention may be either a magnetic toner containing a magnetic material or a non-magnetic toner containing no magnetic material.

  The toner of the present invention can be produced by mixing toner particles and an external additive using a Henschel mixer or a V blender. In addition, when the toner particles are produced by a wet method, external addition can be performed by a wet method.

The lubricating particles added to the toner of the present invention include solid lubricants such as graphite, molybdenum disulfide, talc, fatty acids, fatty acid metal salts, low molecular weight polyolefins such as polypropylene, polyethylene, and polybutene, and softening points by heating. Aliphatic amides such as silicones, oleic amides, erucic acid amides, ricinoleic acid amides, stearic acid amides, and plants such as carnauba wax, rice wax, candelilla wax, tree wax, jojoba oil etc. Mineral waxes, animal waxes such as beeswax, montan wax, ozokerite, ceresin, paraffin wax, microcrystalline wax, Fischer-Tropsch wax, etc., petroleum waxes, and their modified products can be used alone. Use in Or it may be used in combination.
However, the average particle size may be in the range of 0.1 to 10 μm, and the particles having the above chemical structure may be pulverized to have the same particle size. The amount added to the toner is preferably in the range of 0.05 to 2.0 mass%, more preferably 0.1 to 1.5 mass%.

To the toner of the present invention, inorganic fine particles, organic fine particles, composite fine particles obtained by adhering inorganic fine particles to the organic fine particles, and the like can be added for the purpose of removing deposits and deteriorated matters on the surface of the electrophotographic photosensitive member described later. However, inorganic fine particles having excellent polishing properties are particularly preferable.
Inorganic fine particles include silica, alumina, titania, zirconia, barium titanate, aluminum titanate, strontium titanate, magnesium titanate, zinc oxide, chromium oxide, cerium oxide, antimony oxide, tungsten oxide, tin oxide, tellurium oxide, Various inorganic oxides such as manganese oxide, boron oxide, silicon carbide, boron carbide, titanium carbide, silicon nitride, titanium nitride, and boron nitride, nitrides, borides, and the like are preferably used.

Titanium coupling agents such as tetrabutyl titanate, tetraoctyl titanate, isopropyl triisostearoyl titanate, isopropyl tridecylbenzenesulfonyl titanate, bis (dioctyl pyrophosphate) oxyacetate titanate, γ- (2-aminoethyl) Aminopropyltrimethoxysilane, γ- (2-aminoethyl) aminopropylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane, N-β- (N-vinylbenzylaminoethyl) γ-aminopropyltrimethoxysilane hydrochloride Hexamethyldisilazane, methyltrimethoxysilane, butyltrimethoxysilane, isobutyltrimethoxysilane, hexyltrimethoxysilane, octyltrimethoxysilane, The treatment may be performed with a silane coupling agent such as decyltrimethoxysilane, dodecyltrimethoxysilane, phenyltrimethoxysilane, o-methylphenyltrimethoxysilane, or p-methylphenyltrimethoxysilane.
In addition, hydrophobic treatment with a higher fatty acid metal salt such as silicone oil, aluminum stearate, zinc stearate or calcium stearate is also preferably used.

  Examples of the organic fine particles include styrene resin particles, styrene acrylic resin particles, polyester resin particles, and urethane resin particles.

If the particle size is too small, the polishing ability is insufficient, and if it is too large, the surface of the electrophotographic photosensitive member is likely to be damaged. Therefore, the average particle size is 5 nm to 1000 nm, preferably 5 nm to 800 nm, more preferably 5 nm. Those at ˜700 nm are used.
Moreover, it is preferable that the sum with the addition amount of slippery particles is 0.6 mass% or more.

  Other inorganic oxides added to the toner are small-diameter inorganic oxides with a primary particle size of 40 nm or less for powder flowability, charge control, etc. It is preferable to add a large-diameter inorganic oxide. These inorganic oxide fine particles may be known ones, but it is preferable to use silica and titanium oxide in combination for precise charge control. Further, the surface treatment of the small-diameter inorganic fine particles increases the dispersibility and increases the effect of increasing the powder fluidity.

  In addition, the color toner for electrophotography is used by mixing with a carrier. As the carrier, iron powder, glass beads, ferrite powder, nickel powder, or a magnetic powder-dispersed resin carrier in which magnetic powder is dispersed in a resin. Those having a resin coating on their surface are used. The mixing ratio with the carrier can be set as appropriate.

-Other configurations-
The surface of the electrophotographic toner of the present invention may be covered with a surface layer. It is desirable that the surface layer does not greatly affect the mechanical properties and melt viscoelastic properties of the entire toner. For example, if the surface layer of non-melting or high melting point covers the toner thickly, the low-temperature fixability due to the use of the crystalline polyester resin cannot be sufficiently exhibited. Therefore, it is desirable that the thickness of the surface layer is thin, and specifically, it is preferable to be within a range of 0.001 to 0.5 μm.

In order to form a thin surface layer in the above range, a method of chemically treating the surface of particles containing binder resin, colorant, inorganic fine particles added as necessary, and other materials is preferable. used.
Examples of the component constituting the surface layer include silane coupling agents, isocyanates, vinyl monomers, and the like, and it is preferable that a polar group is introduced into the component, and it is chemically bonded. As a result, the adhesive force between the toner and the transfer medium such as paper increases.

The polar group may be any polar functional group, for example, carboxyl group, carbonyl group, epoxy group, ether group, hydroxyl group, amino group, imino group, cyano group, amide group, imide group , Ester groups, sulfone groups and the like.
Examples of the chemical treatment method include a strong oxidizing substance such as a peroxide, a method of oxidizing by ozone oxidation, plasma oxidation or the like, a method of bonding a polymerizable monomer containing a polar group by graft polymerization, and the like. By the chemical treatment, the polar group is firmly bonded to the molecular chain of the crystalline resin through a covalent bond.

  In the present invention, a chargeable substance may be chemically or physically attached to the toner particle surface. Further, fine particles such as metal, metal oxide, metal salt, ceramic, resin, and carbon black may be externally added for the purpose of improving charging property, conductivity, powder fluidity, lubricity and the like.

The volume average particle size of the electrophotographic toner of the present invention is preferably 1 to 20 μm, more preferably 2 to 8 μm, and the number average particle size is preferably 1 to 20 μm, more preferably 2 to 8 μm.
The volume average particle size and the number average particle size can be determined, for example, by measuring with a 50 μm aperture diameter using a Coulter counter [TA-II] type (manufactured by Coulter). At this time, the measurement is performed after the toner is dispersed in an electrolyte aqueous solution (Isoton aqueous solution) and dispersed by ultrasonic waves for 30 seconds or more.

The method for producing the electrophotographic toner of the present invention described above is not particularly limited, but the method for producing the electrophotographic toner of the present invention described below is particularly preferable. In addition, since the electrophotographic toner of the present invention has the above-described configuration, it is excellent in toner blocking resistance, image storage stability, and low-temperature fixability.
Further, when the crystalline polyester resin has a crosslinked structure due to unsaturated bonds, it has a wide fixing latitude with good offset resistance, and the toner in the recording medium such as paper. An electrophotographic toner capable of satisfying prevention of excessive penetration can be obtained. Furthermore, it is possible to improve transfer efficiency by making the toner particle shape spherical.

<Electrophotographic developer>
The electrophotographic toner of the present invention can be used as it is as a one-component developer or as a toner in the electrophotographic developer (two-component developer) of the present invention comprising a carrier and a toner. Hereinafter, the two-component developer of the present invention will be described.
The carrier that can be used in the two-component developer is not particularly limited, and a known carrier can be used. For example, a resin-coated carrier having a resin coating layer on the surface of the core material can be exemplified. Further, a resin-dispersed carrier in which a conductive material or the like is dispersed in a matrix resin may be used.

  Coating resins and matrix resins used for carriers include polyethylene, polypropylene, polystyrene, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl ether, polyvinyl ketone, vinyl chloride-vinyl acetate copolymer, styrene-acrylic. Examples thereof include, but are not limited to, acid copolymers, straight silicone resins composed of organosiloxane bonds or modified products thereof, fluororesins, polyesters, polycarbonates, phenol resins, epoxy resins and the like.

Examples of the conductive material include metals such as gold, silver and copper, carbon black, titanium oxide, zinc oxide, barium sulfate, aluminum borate, potassium titanate, tin oxide, and carbon black. It is not limited.
Examples of the core material of the carrier include magnetic metals such as iron, nickel, and cobalt, magnetic oxides such as ferrite and magnetite, and glass beads. However, in order to use the carrier for the magnetic brush method, it is a magnetic material. It is preferable. The volume average particle size of the core material of the carrier is generally 10 to 500 μm, preferably 30 to 100 μm.

In order to coat the surface of the core material of the carrier with a resin, there may be mentioned a method of coating with a coating layer forming solution in which the coating resin and, if necessary, various additives are dissolved in an appropriate solvent. The solvent is not particularly limited and may be appropriately selected in consideration of the coating resin to be used, coating suitability, and the like.
Specific resin coating methods include an immersion method in which the carrier core material is immersed in the coating layer forming solution, a spray method in which the coating layer forming solution is sprayed onto the surface of the carrier core material, and the carrier core material is fluidized air. And a kneader coater method in which the carrier core material and the coating layer forming solution are mixed in a kneader coater and the solvent is removed in a kneader coater.

  The mixing ratio (mass ratio) of the electrophotographic toner of the present invention and the carrier in the two-component developer is preferably in the range of toner: carrier = 1: 100-30: 100, 3: 100-20: A range of about 100 is more preferable.

<Image forming method>
Next, the image forming method of the present invention using the electrophotographic toner of the present invention or the electrophotographic developer of the present invention will be described.
The image forming method of the present invention is formed on the surface of the latent image holding body using a latent image forming step of forming an electrostatic latent image on the surface of the latent image holding body and a developer carried on the developer carrying body. A developing process for developing a latent image by forming an electrostatic latent image, a transferring process for transferring a toner image formed on the surface of the latent image holding member to a surface of a transfer medium such as paper, and a surface of the transfer object A fixing step of thermally fixing the transferred toner image, and using the electrophotographic toner of the present invention or the electrophotographic developer of the present invention as the developer.

  The developer used in the image forming method of the present invention may be either a one-component system or a two-component system. In the case of a one-component system, the electrophotographic toner of the present invention is used as it is, and in the case of a two-component system, the two-component developer of the present invention obtained by mixing the electrophotographic toner of the present invention and the carrier is used. Used. As each of the above steps, a known step in the image forming method can be used.

As the latent image holding member, for example, an electrophotographic photosensitive member and a dielectric recording member can be used. In the case of an electrophotographic photosensitive member, the surface of the electrophotographic photosensitive member is uniformly charged by a corotron charger, a contact charger or the like and then exposed to form an electrostatic latent image (latent image forming step).
Next, the toner particles are adhered to the electrostatic latent image in contact with or in proximity to a developing roll having a developer layer formed on the surface, thereby forming a toner image on the electrophotographic photosensitive member (developing step).
The formed toner image is transferred onto the surface of a transfer medium such as paper using a corotron charger or the like (transfer process).
Further, the toner image transferred to the surface of the transfer target is heat-fixed by a fixing device, and a final toner image is formed. In the heat fixing by the fixing machine, a release agent is usually supplied to a fixing member in the fixing machine in order to prevent an offset or the like.

In the electrophotographic toner of the present invention (including those contained in the two-component developer of the present invention, the same applies hereinafter), when the binder resin has a cross-linked structure, it is excellent in releasability due to its effect, Fixing can be performed without using a release agent or without using a release agent.
The release agent is preferably not used from the viewpoint of eliminating oil adhesion to the transfer target and image after fixing. However, when the supply amount of the release agent is 0 mg / cm ² , the fixing agent is fixed during fixing. Since the amount of wear of the fixing member may increase and the durability of the fixing member may decrease when the member and a transfer medium such as paper come into contact with each other. It is preferable that the amount used is supplied to the fixing member in a small amount within a range of 8.0 × 10 ⁻³ mg / cm ² or less.

When the supply amount of the release agent exceeds 8.0 × 10 ⁻³ mg / cm ² , the image quality deteriorates due to the release agent adhering to the image surface after fixing, and in particular, transmitted light such as OHP is transmitted. When used, such a phenomenon may be prominent. Further, the adhesion of the release agent to the transfer target becomes remarkable, and stickiness may occur. Furthermore, the larger the supply amount of the release agent, the larger the capacity of the tank for storing the release agent, which causes an increase in the size of the fixing device itself.

Although there is no restriction | limiting in particular as said mold release agent, For example, liquid mold release agents, such as modified oils, such as dimethyl silicone oil, fluorine oil, fluoro silicone oil, and amino modified silicone oil, are mentioned. Among these, modified oils such as amino-modified silicone oil are preferable because they are adsorbed on the surface of the fixing member and can form a homogeneous release agent layer, because they have excellent wettability to the fixing member.
Further, from the viewpoint of forming a homogeneous release agent layer, fluorine oil and fluorosilicone oil are preferable.

Fluorine oil or fluorosilicone oil is used as the release agent because the toner for electrophotography of the present invention is not used, and the conventional image forming method cannot reduce the supply amount of the release agent itself. Although not practical in terms of cost, when the electrophotographic toner of the present invention is used, since the supply amount of the release agent can be drastically reduced, there is no practical problem in terms of cost.
The method for supplying the release agent to the surface of the roller or belt, which is a fixing member used for the thermocompression bonding, is not particularly limited. For example, a pad method using a pad impregnated with a liquid release agent, a web method, Examples thereof include a roller method and a non-contact type shower method (spray method). Among these, a web method and a roller method are preferable.
These methods are advantageous in that the release agent can be supplied uniformly and it is easy to control the supply amount. In order to supply the release agent uniformly to the entire fixing member by the shower method, it is necessary to use a separate blade or the like.
The supply amount of the release agent can be measured as follows. That is, when a normal paper (typically a copy paper manufactured by Fuji Xerox Co., Ltd., trade name J paper) used in a general copying machine is passed through a fixing member supplied with a release agent on its surface. The release agent adheres to the plain paper. The attached release agent is extracted using a Soxhlet extractor. Here, hexane is used as the solvent. By quantifying the amount of the release agent contained in the hexane with an atomic absorption analyzer, the amount of the release agent adhering to the plain paper can be quantified. This amount is defined as the amount of release agent supplied to the fixing member.

Examples of the transfer target (recording material) to which the toner image is transferred include plain paper and OHP sheet used for electrophotographic copying machines, printers, and the like. In order to further improve the smoothness of the image surface after fixing, it is preferable that the surface of the transfer object is as smooth as possible. For example, coated paper in which the surface of plain paper is coated with a resin or the like, art paper for printing Etc. can be used suitably.
According to the image forming method using the electrophotographic toner of the present invention, since there is no aggregation of the toner, an image with excellent image quality can be formed, low temperature fixing is possible, and storage of the formed image is possible. Excellent in properties. Furthermore, when the binder resin has a cross-linked structure, there is almost no adhesion of the release agent to the transfer target, so use a transfer target that has adhesiveness on the back side, such as a seal or tape. By forming an image, it is possible to manufacture a sticker, a sticker or the like on which a high-density and high-density image is formed.

<Method for producing electrophotographic toner>
Examples of the method for producing an electrophotographic toner include a kneading and pulverizing method and a wet granulation method, and the wet granulation method is desirable. Further, as the wet granulation method, known methods such as a melt suspension method, an emulsion aggregation method, a dissolution suspension method and the like are preferably mentioned, but since the toner particle size control and shape control are easy, The method for producing the toner for electrophotography of the present invention is preferably an emulsion aggregation method.
Hereinafter, the emulsion aggregation method will be described. The emulsion aggregation method includes an emulsification step of emulsifying the binder resin of the present invention to prepare binder resin emulsion particles, an aggregation step of forming an aggregate including at least the binder resin emulsion particles, and the aggregate A fusion step for fusing. As the binder resin of the present invention used in the method for producing an electrophotographic toner of the present invention, a polyester resin is preferable.

-Emulsification process-
In the emulsification step, the emulsified particles (droplets) of the polyester resin are sheared into a solution obtained by mixing an aqueous medium and a mixed liquid (polymer liquid) containing a sulfonated polyester resin and, if necessary, a colorant. Formed by applying force.
At that time, the viscosity of the polymer liquid can be lowered to form emulsified particles by heating or dissolving the polyester resin in an organic solvent. Moreover, a dispersing agent can also be used for stabilization of emulsified particles and thickening of the aqueous medium. Hereinafter, such a dispersion of emulsified particles may be referred to as a “resin particle dispersion”.

  Examples of the dispersant include water-soluble polymers such as polyvinyl alcohol, methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, sodium polyacrylate, and sodium polymethacrylate, sodium dodecylbenzenesulfonate, sodium octadecylsulfate, and oleic acid. Anionic surfactants such as sodium, sodium laurate, potassium stearate, cationic surfactants such as laurylamine acetate, stearylamine acetate, lauryltrimethylammonium chloride, zwitterionic surfactants such as lauryldimethylamine oxide, Such as polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene alkylamine, etc. Anion surfactants such as surfactants, tricalcium phosphate, aluminum hydroxide, calcium sulfate, calcium carbonate, and inorganic compounds such as barium carbonate.

When an inorganic compound is used as the dispersant, a commercially available product may be used as it is. However, for the purpose of obtaining fine particles, a method of producing fine particles of an inorganic compound in the dispersant may be employed. As the usage-amount of the said dispersing agent, 0.01-20 mass parts is preferable with respect to 100 mass parts of said polyester resins (binder resin).
In the emulsification step, the polyester resin is copolymerized with a dicarboxylic acid having a sulfonic acid group (that is, a suitable amount of a dicarboxylic acid-derived component having a sulfonic acid group is included in the acid-derived component). ) And dispersion stabilizers such as surfactants can be reduced, or emulsified particles can be formed without using them.

Examples of the organic solvent include ethyl acetate and toluene, which are appropriately selected according to the polyester resin.
As the usage-amount of the said organic solvent, it is 50-5000 mass with respect to 100 mass parts of total amounts of the said polyester resin and the other monomer (henceforth abbreviated as "polymer") used as needed. Part is preferable, and 120 to 1000 parts by mass are more preferable. In addition, a colorant can be mixed before forming the emulsified particles. The colorant used is the same as already described in the section “Colorant” of the electrophotographic toner of the present invention.

Examples of the emulsifier used when forming the emulsified particles include a homogenizer, a homomixer, a pressure kneader, an extruder, and a media disperser. The size of the emulsified particles (droplets) of the polyester resin is preferably 0.01 to 1 μm, more preferably 0.03 to 0.3 μm, more preferably 0.03 to 0.03 in terms of the average particle size (volume average particle size). 0.4 μm is more preferable.
As a method for dispersing the colorant, any method such as a general dispersion method such as a rotary shear type homogenizer, a ball mill having a medium, a sand mill, or a dyno mill can be used, and is not limited at all. If necessary, an aqueous dispersion of these colorants can be prepared using a surfactant, or an organic solvent dispersion of these colorants can be prepared using a dispersant. Hereinafter, such a colorant dispersion may be referred to as a “colored particle dispersion”. As the surfactant and the dispersing agent used for dispersion, the same dispersing agents that can be used when dispersing the polyester resin can be used.

  The addition amount of the colorant is preferably 1 to 20% by mass, more preferably 1 to 10% by mass, and still more preferably 2 to 10% by mass with respect to the total amount of the polymer. 2 to 7% by mass is particularly preferable. When the colorant is mixed in the emulsification step, the polymer and the colorant can be mixed by mixing the colorant or the organic solvent dispersion of the colorant with the organic solvent solution of the polymer. .

-Aggregation process-
In the aggregation step, the obtained emulsified particles are aggregated by heating at a temperature in the vicinity of the melting point of the polyester resin and at a temperature below the melting point to form an aggregate. Formation of the aggregate of the emulsified particles is performed by acidifying the pH of the emulsion under stirring. As said pH, 2-6 are preferable, 2.5-5 are more preferable, and 2.5-4 are more preferable. At this time, it is also effective to use a flocculant.
As the flocculant to be used, a surfactant having a reverse polarity to the surfactant used for the dispersant, an inorganic metal salt, and a metal complex having a valence of 2 or more can be preferably used. In particular, the use of a metal complex is particularly preferable because the amount of the surfactant used can be reduced and the charging characteristics are improved.

  Examples of the inorganic metal salt include metal salts such as calcium chloride, calcium nitrate, barium chloride, magnesium chloride, zinc chloride, aluminum chloride, and aluminum sulfate, and polyaluminum chloride, polyaluminum hydroxide, and calcium polysulfide. Examples thereof include inorganic metal salt polymers. Of these, aluminum salts and polymers thereof are particularly preferred. In order to obtain a sharper particle size distribution, the valence of the inorganic metal salt is divalent than monovalent, trivalent than bivalent, trivalent than trivalent, and tetravalent than trivalent. The inorganic metal salt polymer is more suitable.

-Fusion process-
In the fusion step, under the same agitation as in the aggregation step, the aggregation suspension is stopped by setting the pH of the suspension of the aggregate to a range of 3 to 7, and heated at a temperature equal to or higher than the melting point of the polyester resin. To fuse the aggregates. There is no problem if the heating temperature is equal to or higher than the melting point of the polyester resin. The heating time may be performed so that the fusion is sufficiently performed, and may be performed for about 0.5 to 10 hours.
The fused particles obtained by fusing can be made into toner particles through a solid-liquid separation process such as filtration and, if necessary, a washing process and a drying process. In this case, in order to ensure sufficient charging characteristics and reliability as a toner, it is preferable to sufficiently wash in the washing step. In the drying process, an arbitrary method such as a normal vibration type fluidized drying method, a spray drying method, a freeze drying method, or a flash jet method can be adopted. It is desirable that the toner particles have a moisture content after drying of 1.0% or less, preferably 0.5% or less.

  In the fusion step, a crosslinking reaction may be performed when the polyester resin is heated to a melting point or higher, or after the fusion is completed. Moreover, a crosslinking reaction can also be performed simultaneously with aggregation. When the crosslinking reaction is performed, for example, an unsaturated sulfonated crystalline polyester resin obtained by copolymerizing a double bond component as a binder resin is used, and a radical reaction is caused to the resin to introduce a crosslinked structure. . At this time, the following polymerization initiator is used.

  Examples of the polymerization initiator include t-butyl peroxy-2-ethylhexanoate, cumyl perpivalate, t-butyl peroxylaurate, benzoyl peroxide, lauroyl peroxide, octanoyl peroxide, di-t. -Butyl peroxide, t-butyl cumyl peroxide, dicumyl peroxide, 2,2'-azobisisobutyronitrile, 2,2'-azobis (2-methylbutyronitrile), 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), 1,1-bis (t-butylperoxy) 3,3,5-trimethylcyclohexane 1,1-bis (t-butylperoxy) cyclohexane, 1,4-bis (t-butylperoxyca) Bonyl) cyclohexane, 2,2-bis (t-butylperoxy) octane, n-butyl 4,4-bis (t-butylperoxy) valerate, 2,2-bis (t-butylperoxy) butane, , 3-bis (t-butylperoxyisopropyl) benzene, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, 2,5-dimethyl-2,5-di (t-butylper) Oxy) hexane, 2,5-dimethyl-2,5-di (benzoylperoxy) hexane, di-t-butyldiperoxyisophthalate, 2,2-bis (4,4-di-t-butylperoxy) (Cyclohexyl) propane, di-t-butylperoxy α-methylsuccinate, di-t-butylperoxydimethylglutarate, di-t-butylperoxyhexahydrotereph Tartrate, di-t-butylperoxyazelate, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, diethylene glycol-bis (t-butylperoxycarbonate), di-t-butylper Oxytrimethyl adipate, tris (t-butylperoxy) triazine, vinyltris (t-butylperoxy) silane, 2,2'-azobis (2-methylpropionamidine dihydrochloride), 2,2'-azobis [N- (2-carboxyethyl) -2-methylpropionamidine], 4,4′-azobis (4-cyanovaleric acid) and the like.

These polymerization initiators can be used alone or in combination of two or more. The amount and type of the polymerization initiator are selected depending on the amount of unsaturated sites in the polymer and the type and amount of the coexisting colorant. The polymerization initiator may be mixed with the polymer in advance before the emulsification step, or may be incorporated into the aggregate in the aggregation step. Further, it may be introduced after the fusion step or after the fusion step. In the case of introduction after the aggregation step, the fusion step, or the fusion step, a solution in which the polymerization initiator is dissolved or emulsified is added to a particle dispersion (resin particle dispersion or the like). These polymerization initiators may be added with known crosslinking agents, chain transfer agents, polymerization inhibitors and the like for the purpose of controlling the degree of polymerization.
According to the method for producing an electrophotographic toner of the present invention described above, an electrophotographic toner having excellent charging stability can be provided.

EXAMPLES Hereinafter, although this invention is demonstrated further in detail using an Example, this invention is not limited by the following Example. In the following, “part” means part by mass.
The average particle size of the toner particles was measured using a Coulter counter (TA2 type, manufactured by Coulter).
The average particle diameters of the resin particles, the colorant, and the release agent were measured using a laser diffraction particle size distribution measuring apparatus (LA-700, manufactured by Horiba Seisakusho).
The weight average molecular weight (Mw) of the resin in the resin particles and toner particles was measured using gel permeation chromatography (HLC-8120GPC, manufactured by Tosoh Corporation).
In order to measure rare earth elements (scandium, yttrium), the fluorescence intensity of the toner obtained using fluorescent x-rays is measured. The amount of rare earth elements contained in the toner was converted from a separately prepared calibration curve.

Evaluation of charging property was performed as follows. An electrophotographic toner having a surface hydrophobized silica fine particle having a primary particle size of 40 nm (hydrophobic silica manufactured by Nippon Aerosil Co., Ltd .: RX50) 0.8 mass%, a reaction product of metatitanic acid and isobutyltrimethoxysilane Metatitanic acid compound fine particles having an average primary particle diameter of 20 nm (treated with 100 parts by mass of metatitanic acid and 50 parts by mass of isobutyltrimethoxysilane) are added and mixed to prepare an externally added electrophotographic toner. did. 8 parts by mass of the externally added electrophotographic toner obtained and 92 parts by mass of a methyl methacrylate resin-coated carrier were placed in a V-blender and stirred for 20 minutes, and a developing machine of A color full-color copying machine (manufactured by Fuji Xerox Co., Ltd.). Then, after setup, the charge amount was measured with a blow-off charge amount measuring device (manufactured by Toshiba) (using a mesh opening of 20 μm). When the charge amount was 10 to 40 μC / g, the determination was “good”, and the other range was “x”.
The charge amount was measured under two conditions of 30 ° C. RH 80% (A-zone) and 10 ° C. RH 15% (C-zone).

Regarding the evaluation of the electrophotographic developer, an image was formed with a modified Docu Center Color500CP machine manufactured by Fuji Xerox Co., Ltd. using an externally added electrophotographic toner, and the initial image quality (10th sheet) and the 50,000th sheet were obtained. Each of the images was performed by visually observing image quality maintenance (melting unevenness) and background stains.
Image quality evaluation and background stain were evaluated according to the following evaluation criteria.
-Evaluation criteria-
・ ○: No problem in the image ・ △: Slight dirt was observed but no problem in practical use ・ ×: Large dirt was observed and practical use was not possible

The overall evaluation of the electrophotographic toner was performed according to the following evaluation criteria.
○: No problem Δ: Some dirt was observed but there was no practical problem ×: Large dirt was observed and practically unusable These evaluations are summarized in Table 1.

[Example 1]
-Synthesis of crystalline polyester resin (1)-
200 parts of 1,9 nonanediol, 260 parts of dododecanedioic acid, 7.4 parts of 5-sulfoisophthalic acid dimethyl ester, 21 parts of 5-t-butylisophthalic acid, 12.6 parts of scandium triflate as a catalyst, After nitrogen substitution, the temperature is raised to 100 ° C. to dissolve. While maintaining the temperature at 100 ° C., the pressure in the flask is reduced to 20 mmHg over 1 hour with stirring. Furthermore, the degree of vacuum was lowered to 10 mmHg or less, and the reaction was continued for 7 hours to obtain a resin. The molecular weight was weight average molecular weight (Mw) = 20000.

-Production of toner for electrophotography (1)-
The obtained crystalline polyester resin (1) (10 parts by mass) and distilled water (90 parts by mass) were emulsified with an emulsifier (Ultra Turrax) at 95 ° C. and 10,000 rpm for 3 minutes to obtain an emulsion. To 100 parts by mass of this emulsified liquid, 4 parts by mass of a copper phthalocyanine pigment (CI pigment blue 15: 3) dispersion (0.4 parts by mass as a solid content) is added, and 10 g of an aqueous solution of 1% by mass aluminum sulfate is slowly added with stirring. Added to agglomerate. After stirring at 60 ° C. for 2 hours, the pH was adjusted to 4.5, the temperature was gradually increased, and the mixture was heated and stirred at 95 ° C. for 20 minutes. Thereafter, it was air-cooled, washed with ion-exchanged water, and freeze-dried to produce an electrophotographic toner (1).
When the average particle diameter of the obtained electrophotographic toner was measured using a Coulter counter [TA-II] type (aperture diameter: 50 μm, manufactured by Coulter), the average particle diameter of the obtained toner particles was 5 .8 μm. Observation with an optical microscope confirmed spherical particles.

[Example 2]
-Synthesis of crystalline polyester resin (2)-
The synthesis of the crystalline polyester resin (1) of Example 1 was the same as that of Example 1 except that the catalyst was changed to 0.126 parts of scandium triflate. The molecular weight was weight average molecular weight (Mw) = 21000.

-Production of toner for electrophotography (2)-
An electrophotographic toner (2) was produced in the same manner as in Example 1 “Production of electrophotographic toner (1)” except that the polyester resin was changed to the crystalline polyester resin (2).
When the average particle diameter of the obtained electrophotographic toner was measured using a Coulter counter [TA-II] type (aperture diameter: 50 μm, manufactured by Coulter), the average particle diameter of the obtained toner particles was 5 0.7 μm. Observation with an optical microscope confirmed spherical particles.

[Example 3]
-Synthesis of crystalline polyester resin (3)-
The synthesis of the crystalline polyester resin (1) of Example 1 was the same as that of Example 1 except that the catalyst was changed to 5.6 parts of scandium triflate. The molecular weight was weight average molecular weight (Mw) = 19000.

-Production of toner for electrophotography (3)-
An electrophotographic toner (3) was produced in the same manner as in Example 1 "Production of electrophotographic toner (1)" except that the polyester resin was changed to the crystalline polyester resin (3).
When the average particle size of the obtained electrophotographic toner was measured using a Coulter counter [TA-II] type (aperture diameter: 50 μm, manufactured by Coulter), the average particle size of the obtained toner particles was 6 It was 5 μm. Observation with an optical microscope confirmed spherical particles.

[Example 4]
-Synthesis of crystalline polyester resin (4)-
In the synthesis of the crystalline polyester resin (1) of Example 1, the composition of the resin was changed to 301 parts by mass of dimethyl terephthalate, 248 parts by mass of 1,9-nonanediol, and the catalyst was changed to 12.6 parts of scandium triflate. The others were the same as in Example 1. The molecular weight was weight average molecular weight (Mw) = 19000.

-Production of toner for electrophotography (4) (dissolution suspension method)-
A dispersion was prepared by dispersing 28 parts by mass of a crystalline polyester resin (4), 5 parts by mass of a copper phthalocyanine pigment (CI Pigment Blue 15: 3), and 60 parts by mass of toluene using a sand mill. To 36 parts by mass of a 3.0% by mass aqueous solution of carboxymethyl cellulose, 45 parts by mass of a 40% by mass calcium carbonate suspension and 45 parts by mass of water were added. The total amount of the dispersion was added to this at 50 ° C., and suspended by stirring for 3 minutes at 50 ° C. and 10,000 rpm with an emulsifier (trade name: Ultra Turrax, manufactured by JUNKE & KUNKEL).
Subsequently, toluene and water were evaporated as much as possible under a nitrogen stream to obtain a crosslinked particle dispersion. About 5 times the amount of water is added to the resulting crosslinked particle dispersion, calcium carbonate is dissolved in hydrochloric acid, washed repeatedly with water, and finally electrophotographic toner (4) is produced by decompression and lyophilization. did.
When the average particle size of the obtained electrophotographic toner was measured using a Coulter counter [TA-II] type (aperture diameter: 50 μm, manufactured by Coulter), the average particle size of the obtained toner particles was 6 .3 μm. It was spherical when observed using an optical microscope.

[Example 5]
-Synthesis of crystalline polyester resin (5)-
In the synthesis of the crystalline polyester resin (1) of Example 1, the structure of the resin was the same as that of Example 1 except that the catalyst was changed to 12.6 parts of scandium triflimide. The molecular weight was weight average molecular weight (Mw) = 18000.

-Production of toner for electrophotography (5)-
An electrophotographic toner (5) was produced in the same manner as in Example 1 “Production of electrophotographic toner (1)” except that the polyester resin was changed to the crystalline polyester resin (5).
When the average particle size of the obtained electrophotographic toner was measured using a Coulter counter [TA-II] type (aperture diameter: 50 μm, manufactured by Coulter), the average particle size of the obtained toner particles was 6 It was 5 μm. Observation with an optical microscope confirmed spherical particles.

[Example 6]
-Synthesis of crystalline polyester resin (6)-
In the synthesis of the crystalline polyester resin (1) of Example 1, the structure of the resin was the same as that of Example 1 except that the catalyst was changed to 12.6 parts of yttrium triflate. The molecular weight was weight average molecular weight (Mw) = 19000.

-Production of toner for electrophotography (6)-
An electrophotographic toner (6) was produced in the same manner as in Example 1 "Production of electrophotographic toner (1)" except that the polyester resin was changed to the crystalline polyester resin (6).
When the average particle size of the obtained electrophotographic toner was measured using a Coulter counter [TA-II] type (aperture diameter: 50 μm, manufactured by Coulter), the average particle size of the obtained toner particles was 6 It was 5 μm. Observation with an optical microscope confirmed spherical particles.

[Example 7]
-Synthesis of crystalline polyester resin (7)-
In the synthesis of the crystalline polyester resin (1) of Example 1, the resin composition was 200 parts 1,6-hexanediol, 260 parts 1,9-nonanedicarboxylic acid, 7.4 parts dimethyl 5-sulfoisophthalic acid. The procedure was the same as in Example 1 except that. The molecular weight was weight average molecular weight (Mw) = 19000.

-Production of toner for electrophotography (7)-
An electrophotographic toner (7) was produced in the same manner as in Example 1 "Production of electrophotographic toner (1)" except that the polyester resin was changed to the crystalline polyester resin (7).
When the average particle size of the obtained electrophotographic toner was measured using a Coulter counter [TA-II] type (aperture diameter: 50 μm, manufactured by Coulter), the average particle size of the obtained toner particles was 6 It was 5 μm. Observation with an optical microscope confirmed spherical particles.

[Comparative Example 1]
-Synthesis of crystalline polyester resin (8)-
The synthesis of the crystalline polyester resin (1) of Example 1 was the same as that of Example 1 except that the catalyst was changed to 0.03 part of scandium triflate. The molecular weight was weight average molecular weight (Mw) = 15000.

-Production of toner for electrophotography (8)-
An electrophotographic toner (8) was produced in the same manner as in Example 1 “Production of electrophotographic toner (1)” except that the polyester resin was changed to the crystalline polyester resin (8).
When the average particle diameter of the obtained electrophotographic toner was measured using a Coulter counter [TA-II] type (aperture diameter: 50 μm, manufactured by Coulter), the average particle diameter of the obtained toner particles was 5 0.7 μm. Observation with an optical microscope confirmed spherical particles.

[Comparative Example 2]
-Synthesis of crystalline polyester resin (9)-
In the synthesis of the crystalline polyester resin (1) of Example 1, the catalyst was changed to 50 parts of scandium triflate, and the resin composition was the same as that of Example 1. The molecular weight was weight average molecular weight (Mw) = 20000.

Production of electrophotographic toner (9) In the same manner as in Example 1 “Production of electrophotographic toner (1)”, except that the crystalline polyester resin (9) was used, the electrophotographic toner (9) was prepared. Manufactured.
When the average particle diameter of the obtained electrophotographic toner was measured using a Coulter counter [TA-II] type (aperture diameter: 50 μm, manufactured by Coulter), the average particle diameter of the obtained toner particles was 5 .8 μm. Observation with an optical microscope confirmed spherical particles.

[Comparative Example 3]
-Synthesis of crystalline polyester resin (10)-
In the synthesis of the crystalline polyester resin (1) of Example 1, the structure of the resin was the same as in Example 1 except that the catalyst was changed to 0.2 part of tetra-n-butyl titanate. The mixture was stirred for 3 hours at 180 ° C. with mixing and stirring after nitrogen substitution, and polymerized for 5 hours under reduced pressure. Thereafter, in 4 hours, the temperature was finally raised to 220 ° C., and finally the reaction was performed for a total of 12 hours to synthesize a resin. The molecular weight was weight average molecular weight (Mw) = 25000.

Production of electrophotographic toner (10) In the same manner as in Example 1 "Production of electrophotographic toner (1)", except that the polyester resin was changed to the crystalline polyester resin (10), the electrophotographic toner ( 10) was produced.
When the average particle diameter of the obtained electrophotographic toner was measured using a Coulter counter [TA-II] type (aperture diameter: 50 μm, manufactured by Coulter), the average particle diameter of the obtained toner particles was 6 It was 5 μm. Observation with an optical microscope confirmed spherical particles.

  As is apparent from Table 1, the electrophotographic toner of the present invention has a small amount of charge dependency on the environment.

Claims (9)

  A binder resin containing 1 to 10,000 ppm of rare earth elements.   The binder resin according to claim 1, comprising a polyester resin containing 1 to 10,000 ppm of a rare earth element.   The binder resin according to claim 1, wherein the rare earth element is Sc, Y, Yb, or Sm. The binder resin of Claim 1 synthesize | combined using the catalyst represented by following formula (1).
X (OSO ₂ CF ₃ ) ₃ formula (1)
(In formula (1), X represents Sc, Y, Yb or Sm.) The binder resin of Claim 1 synthesize | combined using the catalyst represented by following formula (2).
X (N (OSO ₂ CF ₃ ) ₂ ) ₃ formula (2)
(In the formula (2), X represents Sc, Y, Yb or Sm.)   An electrophotographic toner containing at least the binder resin according to claim 1 and a colorant. An emulsification step of emulsifying the binder resin according to any one of claims 1 to 5 to prepare binder resin emulsified particles;
An aggregation step for forming an aggregate containing at least the binder resin emulsified particles;
A fusion step of fusing the aggregates;
A method for producing an electrophotographic toner comprising:   An electrophotographic developer comprising the electrophotographic toner according to claim 6 and a carrier. A latent image forming step for forming an electrostatic latent image on the surface of the latent image holding member and a developer carried on the developer carrying member are used to develop the electrostatic latent image formed on the surface of the latent image holding member. A developing step for forming a toner image, a transfer step for transferring the toner image formed on the surface of the latent image holding member to the surface of the transfer target, and a fixing step for thermally fixing the toner image transferred on the surface of the transfer target. And an image forming method comprising:
The image forming method according to claim 6, wherein the developer is the electrophotographic toner according to claim 6 or the electrophotographic developer according to claim 8.