JP2001281909A - Electrostatic image developing toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrostatic image developing toner having low fixing temperature which can respond for the requirements of energy saving, fast printing and copying and color printing or the like, which has excellent storage property and fluidity and high offset temperature and which can form an image of good picture quality with high resolution. SOLUTION: In the electrostatic image developing toner containing at least a binder resin, a coloring agent and a polyfunctional ester compound, the polyfunctional ester compound is an aromatic polyvalent carboxylic acid alkylester having >=15 carbon atoms in the alkyl part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic image developing toner for developing an electrostatic latent image formed on a photoreceptor by an electrophotographic method, an electrostatic printing method or the like. Excellent in both storage and storage (blocking resistance)
In addition, the present invention relates to an electrostatic image developing toner capable of forming a high quality image.

[0002]

2. Description of the Related Art In an image forming apparatus such as an electrophotographic apparatus and an electrostatic printing apparatus, an electrostatic latent image (electrostatic image) is formed by performing image exposure on a uniformly and uniformly charged photoconductor. Then, a developer is attached to the exposed area or the non-exposed area to perform development. The developer image formed on the photoconductor is usually
After being transferred onto a transfer material such as paper or OHP sheet, heating,
It is fixed on the transfer material by various methods such as pressurization and solvent vapor. As the developer, an electrostatic image developing toner composed of colored particles in which a colorant and other additives (eg, a charge control agent, a release agent, etc.) are dispersed in a binder resin is used.

Conventionally, as a toner for developing an electrostatic image, a pulverized toner obtained by pulverizing and classifying a resin composition obtained by melting and mixing a colorant and other additives into a thermoplastic resin has been the mainstream. . In recent years, polymerized toners that can easily control the particle size, omit complicated steps such as pulverization and classification, and have good image quality have been widely used. In general, a polymerization method toner is prepared by introducing a monomer composition containing a polymerizable monomer, a colorant, a charge controlling agent, a release agent, etc., into an aqueous dispersion medium containing a dispersion stabilizer, and subjecting it to high shear. It is manufactured by dispersing using a stirring device having power, forming fine droplets of the monomer composition, and then performing suspension polymerization. A polymer formed by polymerization of the polymerizable monomer serves as a binder resin, in which a colorant and other additives are dispersed.

The toner for developing an electrostatic image can form a fine, high-density, high-quality image without deterioration of the image quality due to environmental changes such as temperature and humidity. It is required that copying be possible. In addition to these characteristics, recently, the toner for developing an electrostatic image has been required to be able to contribute to energy saving, to be able to cope with high-speed printing and copying, and to cope with colorization. For this reason, there is a demand for a toner for developing an electrostatic image to maintain a high image quality, without impairing the storability, and further improve the fixability such as a decrease in the fixing temperature.

More specifically, recently, power consumption has been reduced in image forming apparatuses such as electrophotographic copying machines and printers using an electrostatic image developing toner. Among the electrophotographic methods, a step of consuming energy in particular is a fixing step for fixing after transferring a toner image on a photoreceptor onto a transfer material such as paper. Generally, in the fixing step, a fixing process is performed to fix the toner image on the transfer material.
A fixing roll or a fixing belt heated to 0 ° C. or higher is used, and electricity is used as an energy source. It is required to lower the fixing temperature from the viewpoint of energy saving.

Recently, there has been a demand for higher printing speed and copying speed. In particular, as image forming apparatuses become more complex and personal computers are networked, demands for high-speed printing and high-speed copying are increasing. Therefore, in high-speed printers and high-speed copying machines, it is necessary to shorten the fixing time.

In designing an electrostatic charge image developing toner, as a method of responding to the demand from such an image forming apparatus, there is a method of lowering the glass transition temperature of the binder resin. However, when the glass transition temperature of the binder resin is lowered, the toner particles are blocked from each other during storage of the toner or in the toner box of the developing device to form aggregates, which results in a toner having poor storage stability. .

Further, recently, color printing and color copying techniques by an electrophotographic system have been developed. In order to perform color printing or color copying, the electrostatic latent image on the photoreceptor is usually developed using three or four color toners, and is transferred onto the transfer material at one time or sequentially, and then fixed. are doing. For this reason, the layer thickness of the toner to be fixed is larger than that of the black and white image. Further, in order to form a predetermined color tone by mixing colors, it is necessary to uniformly fuse a plurality of overlapping color toners at the time of fixing.

For this reason, the color toner is designed to have a lower melt viscosity near the fixing temperature than the conventional one,
It must be easy to melt. Methods for lowering the melt viscosity of the toner include methods such as lowering the molecular weight of the binder resin and lowering the glass transition temperature as compared with conventional toners. However, any of these methods easily causes blocking and results in a toner having poor storage stability. As described above, when a toner modification method corresponding to energy saving, high-speed printing and copying, and colorization is adopted, the storage stability of the toner is reduced.

Conventionally, in order to obtain a toner for developing electrostatic images having good low-temperature fixability, a low-softening point substance having releasability such as paraffin wax is present in the toner to lower the softening point of the toner. A method has been proposed (Japanese Unexamined Patent Publication No.
3-173067, JP-A-6-161144, etc.). However, with such a toner, it is difficult to achieve high image quality and to achieve a high balance between low-temperature fixability and storage stability.

Japanese Patent Application Laid-Open No. 5-197193 discloses that in a polymerized toner, toner particles contain a high softening point resin (A) and a low softening point substance (B), There has been proposed a toner having a phase separation structure in which a phase exists near the surface and a B phase mainly composed of a low softening point substance does not exist near the surface. However, although this toner has good blocking resistance, the fixing temperature is still high, and the low-temperature fixing property is not sufficient. Further, it is difficult to incorporate a large amount of a low softening point substance such as a wax insoluble in the polymerizable monomer into the toner. Moreover, if a low softening point substance is present in the toner at the amount indicated in the examples of the publication, the gloss becomes excessive and it is difficult to obtain good image quality.

JP-A-7-98511 discloses a binder resin, a colorant, and a polyfunctional polyester having a tertiary and / or quaternary carbon atom and obtained from a difunctional or higher functional alcohol compound or carboxylic acid compound. A toner for developing an electrostatic image containing a compound has been proposed. This publication describes that this toner is excellent in low-temperature fixability, anti-offset property and the like, and is suitable for forming a full-color image. However, since the polyfunctional polyester compound specifically disclosed in the publication has high crystallinity, it needs to be dissolved in a polymerizable monomer at a high temperature of about 60 ° C. to be contained in a polymerized toner. There is. After the polyfunctional polyester is dissolved in the polymerizable monomer at a high temperature, a polymerization initiator is also added at a high temperature, so that it is difficult to control the polymerization reaction and it is not easy to obtain a uniform toner.

JP-A-11-133657 proposes a toner containing at least a binder resin, a colorant, and a wax, wherein the wax contains a specific ester compound. However, it is necessary to heat the polymerizable monomer to about 65 ° C. in order to include the ester compound in the polymerization toner. Further, the publication describes that it is preferable that the wax is substantially stripped in a spherical and / or spindle shape in a state in which the wax is not compatible with the binder resin. However, if wax that plays a role in plasticizing the binder resin at the time of fixing exists inside the toner in a phase-separated manner, a large amount of heat is actually required to melt the toner at the time of fixing, and low energy is required. Go backwards.

[0014]

SUMMARY OF THE INVENTION An object of the present invention is to provide a low fixing temperature, energy saving, high-speed printing and copying, colorization, and the like. Another object of the present invention is to provide a toner for developing an electrostatic image, which has a high offset temperature and can form high resolution and good image quality.

The present inventors have conducted intensive studies to achieve the above object. As a result, the present inventors have found that an electrostatic charge containing at least a binder resin, a colorant and a polyfunctional ester compound, and further containing various additives as necessary. It has been found that the above object can be achieved by including, in the toner for image development, an alkyl alkyl aromatic polycarboxylate having an alkyl portion of 15 or more as the polyfunctional ester compound. Since this specific polyfunctional ester compound has good solubility in a polymerizable monomer, it can be easily applied to a polymerization toner. The polyfunctional ester compound acts on the toner as a modifier such as a softener, a release agent, and an anti-offset agent. The present invention has been completed based on these findings.

[0016]

According to the present invention, in a toner for developing an electrostatic image containing at least a binder resin, a colorant and a polyfunctional ester compound, the polyfunctional ester compound has a carbon atom in the alkyl portion. An electrostatic charge image developing toner is provided, which is an aromatic polycarboxylic acid alkyl ester having 15 or more atoms.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Alkyl aromatic polycarboxylic acids
The alkyl aromatic polycarboxylic acid ester used in the present invention is an aromatic polycarboxylic acid having two or more carboxyl groups and an aromatic polycarboxylic acid having 15 or more carbon atoms, preferably 15 to 3 carbon atoms.
It is a polyfunctional ester compound obtained by dehydration condensation with 0, more preferably 16 to 25 linear or branched higher alcohols. If the number of carbon atoms in the alkyl portion is too small, the aromatic polycarboxylic acid alkyl ester acts as a plasticizer for the binder resin, lowering the glass transition temperature of the toner more than necessary, resulting in a toner having poor storage stability. Would.

Specific examples of the aromatic polycarboxylic acid include:
Benzenedicarboxylic acids such as orthophthalic acid, isophthalic acid, terephthalic acid, 5-methylisophthalic acid; 1,
Benzenetricarboxylic acids such as 2,3-benzenetricarboxylic acid, 1,2,4-benzenetricarboxylic acid and 1,3,5-benzenetricarboxylic acid; 1,2,3,4-benzenetetracarboxylic acid; Benzenetetracarboxylic acids such as 1,3,5-benzenetetracarboxylic acid and 1,2,4,5-benzenetetracarboxylic acid; benzenepentacarboxylic acids such as benzenepentacarboxylic acid and methylbenzenepentacarboxylic acid; benzenehexacarboxylic acid A naphthalenedicarboxylic acid such as 1,8-naphthalenedicarboxylic acid;

Specific examples of higher alcohols having 15 or more carbon atoms include pentadecyl alcohol (C = 1
5), cetyl alcohol (C = 16), heptadecyl alcohol (C = 17), stearyl alcohol (C = 1)
8), nonadecyl alcohol (C = 19), eicosyl alcohol (C = 20), behenyl alcohol (C = 2)
2; 1-docosanol), seryl alcohol (C = 2
6), mesylyl alcohol (C = 30) and the like.

The dehydration condensation reaction between the aromatic polycarboxylic acid and the higher alcohol is not particularly limited as long as the alkyl ester can be obtained. It can be obtained by reacting in a solvent under basic conditions. Among the aromatic polycarboxylic acid alkyl esters, those exhibiting a maximum endothermic peak in a region of 50 to 80 ° C. in a DSC curve measured by a differential scanning calorimeter when the temperature is raised,
As it can give a toner with excellent low-temperature fixability,
Particularly preferred.

When a toner is produced by a polymerization method, styrene or a monomer mixture containing styrene is often used as a polymerizable monomer. Therefore, an aromatic polycarboxylic acid alkyl ester is dissolved in styrene. It is preferable that the property is good. Specifically, the amount of the aromatic polycarboxylic acid alkyl ester dissolved in 100 g of styrene measured at 35 ° C. (g / 100 g ST; 35 ° C.)
Is preferably 5 g or more. The dissolution amount is more preferably at least 10 g, particularly preferably at least 15 g. When the amount of the aromatic polycarboxylic acid alkyl ester dissolved in styrene at 35 ° C. is too small, the solubility of the aromatic polycarboxylic acid alkyl ester in the polymerizable monomer containing styrene is reduced. As a result, the content of the aromatic polycarboxylic acid alkyl ester in the polymerization toner becomes insufficient, and it becomes difficult to sufficiently lower the fixing temperature. On the other hand, if the amount is too small, it is necessary to heat the polymerizable monomer to a high temperature in order to dissolve a sufficient amount of the alkyl alkyl polycarboxylate in the polymerizable monomer. Moreover,
Even when such an aromatic polycarboxylic acid alkyl ester is heated and dissolved in a polymerizable monomer, it is likely to be non-uniformly dispersed in the resulting polymerized toner.

The acid value of the aromatic polycarboxylic acid alkyl ester used in the present invention is preferably 2 mgKOH / g or less. The upper limit of the acid value is more preferably 1.5
mgKOH / g, particularly preferably 1.0 mgKOH / g
It is. The lower limit of the acid value is preferably 0.05 mg KOH /
g. If the acid value of the aromatic polycarboxylic acid alkyl ester is too high, it has an adverse effect when granulating the droplets of the monomer composition in an aqueous dispersion medium, and the droplet particles have a uniform and stable particle size distribution. Becomes difficult to granulate. In addition, a toner containing an alkyl ester of an aromatic polycarboxylic acid having an acid value that is too high has unstable charging properties under high temperature and high humidity, and it is difficult to obtain a sufficient image density.

The hydroxyl value of the aromatic polycarboxylic acid alkyl ester used in the present invention is preferably 2 mgKOH / g or less. The upper limit of the hydroxyl value is more preferably 1.5 mgKOH / g, particularly preferably 1.0 mgKOH / g.
OH / g. In many cases, the lower limit of the hydroxyl value is 0.1
mg KOH / g. If the hydroxyl value of the aromatic polycarboxylic acid alkyl ester is too high, when the droplets of the monomer composition are granulated in an aqueous dispersion medium, in addition to the fact that the particle size distribution of the droplets tends to spread, In addition, since the aromatic polycarboxylic acid alkyl ester tends to collect on the surface of the droplet, and the affinity of the aromatic polycarboxylic acid alkyl ester with the aqueous dispersion medium is high, coalescence of the droplets easily occurs. .

The aromatic polycarboxylic acid alkyl ester used in the present invention has the above-mentioned various properties,
In a DSC curve measured by a differential scanning calorimeter,
It is preferable that the compound shows a maximum endothermic peak in a range of 50 to 80 ° C. when the temperature is raised. Maximum endothermic peak temperature is 50 ~
The aromatic polycarboxylic acid alkyl ester at 80 ° C. is a substance having a low softening point and can sufficiently contribute to the low-temperature fixability of the toner. This maximum endothermic peak temperature is more preferably 50 to 70 ° C, particularly preferably 50 to 65 ° C.
° C. The toner containing such an aromatic polycarboxylic acid alkyl ester has excellent low-temperature fixability, a high offset temperature, and excellent hot offset resistance.

The proportion of the aromatic polycarboxylic acid alkyl ester is usually 0.1 to 2 parts by weight per 100 parts by weight of the binder resin of the toner or the polymerizable monomer forming the binder resin.
0 parts by weight, preferably 1 to 15 parts by weight. If the proportion of the aromatic polycarboxylic acid alkyl ester is too small, it becomes difficult to obtain a toner having excellent low-temperature fixability. If the proportion of the aromatic polycarboxylic acid alkyl ester is too large, the hot offset resistance is reduced,
Toner filming on the photoreceptor surface is likely to occur.

The toner for developing an electrostatic image The toner for developing an electrostatic image of the present invention may be any colored particles containing at least a binder resin, a colorant, and the above-mentioned alkyl ester of an aromatic polycarboxylic acid. There is no particular limitation on the method, and for example, it can be obtained by a pulverization method or a polymerization method. Examples of the polymerization method include an emulsion polymerization method, an aggregation method, a dispersion polymerization method, and a suspension polymerization method. According to the polymerization method, toner particles on the order of microns can be directly obtained with a relatively small particle size distribution. Further, the toner of the present invention is preferably a toner having a core-shell structure in which a resin coating layer is formed on the surface of colored particles (capsule toner) from the viewpoint of low-temperature fixing. It is particularly preferable that the toner of the present invention is a polymerized toner obtained by a suspension polymerization method from the viewpoint of developer characteristics.

The polymerization toner by suspension polymerization is prepared by mixing a monomer composition containing at least a polymerizable monomer, a colorant, and an aromatic polycarboxylic acid alkyl ester in an aqueous dispersion medium containing a dispersion stabilizer. Can be obtained by subjecting the product to suspension polymerization. The polymer formed by polymerizing the polymerizable monomer becomes the binder resin.

The toner having a core-shell structure can be produced by a method such as a spray drying method, an interfacial reaction method, an in situ polymerization method, or a phase separation method. In particular, the in situ polymerization method and the phase separation method are preferable because of high production efficiency. More specifically, suspension polymerization of a monomer composition containing at least a polymerizable monomer, a colorant, and an alkyl alkyl aromatic polycarboxylate in an aqueous dispersion medium containing a dispersion stabilizer. Using the colored polymer particles obtained by the above as core particles and subjecting the polymerizable monomer for shell to suspension polymerization in the presence of the core particles to form a polymer layer (shell) covering the core particles. Can be obtained by The polymer layer formed by polymerizing the polymerizable monomer for shell becomes the resin coating layer. In the polymerizable monomer composition, if necessary, a crosslinkable monomer,
Various additives such as a macromonomer, a molecular weight modifier, a charge controlling agent, a general-purpose release agent, a lubricant, and a dispersing aid can be contained.

(1) Polymerizable monomer As the polymerizable monomer, a monovinyl monomer is preferable. Specifically, styrene monomers such as styrene, vinyltoluene and α-methylstyrene; acrylic acid, methacrylic acid; methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, Acrylic acid or methacrylic acid such as dimethylaminoethyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, dimethylaminoethyl methacrylate, acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, etc. Acid derivatives; ethylenically unsaturated monoolefins such as ethylene, propylene and butylene; vinyl halides such as vinyl chloride, vinylidene chloride and vinyl fluoride; vinyl acetate such as vinyl acetate and vinyl propionate Esters; vinyl methyl ether, vinyl ethers such as vinyl ethyl ether, vinyl methyl ketone, vinyl ketones such as methyl isopropenyl ketone; 2-vinyl pyridine, 4-vinyl pyridine, N
A nitrogen-containing vinyl compound such as vinylpyrrolidone; Monovinyl monomers can be used alone or in combination of a plurality of monomers. Among the monovinyl monomers, it is preferable to use a styrene monomer and a derivative of (meth) acrylic acid in combination.

(2) Crosslinkable Monomer and Crosslinkable Polymer Use of a crosslinkable monomer and / or crosslinkable polymer together with the polymerizable monomer is effective for improving hot offset.
The crosslinkable monomer is a monomer having two or more polymerizable carbon-carbon unsaturated double bonds. Specifically, aromatic divinyl compounds such as divinylbenzene, divinylnaphthalene and derivatives thereof; diethylenically unsaturated carboxylic esters such as ethylene glycol dimethacrylate and diethylene glycol dimethacrylate; 1,4-butanediol, 1,9- (Meth) acrylates derived from aliphatic both terminal alcohols such as nonanediol; divinyl compounds such as N, N-divinylaniline and divinyl ether;
Compounds having at least two vinyl groups; Examples of the crosslinkable polymer include polyethylene and polypropylene having two or more hydroxyl groups in the molecule, polyester, and (meth) acrylate derived from polysiloxane. These crosslinkable monomers and crosslinkable polymers can be used alone or in combination of two or more. The crosslinkable monomer and / or the crosslinkable polymer are based on 100 parts by weight of the polymerizable monomer.
Usually 10 parts by weight or less, preferably 0.01 to 5 parts by weight,
More preferably, it is used in a ratio of 0.1 to 2 parts by weight.

(3) Macromonomer When a macromonomer is used together with the polymerizable monomer, it is possible to improve the balance between preservability, anti-offset properties and low-temperature fixability. A macromonomer is a relatively long linear molecule having a polymerizable functional group (for example, an unsaturated group such as a carbon-carbon double bond) at the end of a molecular chain. As the macromonomer, the number average molecular weight is usually 1,000 to 3
000 oligomers or polymers are preferred. When a macromonomer having a small number average molecular weight is used, the surface portion of the toner particles becomes soft, and the storage stability decreases. Conversely, when a macromonomer having a large number average molecular weight is used,
The meltability of the macromonomer is poor, and the fixability of the toner decreases.

Specific examples of the macromonomer include polymers obtained by polymerizing styrene, styrene derivatives, methacrylates, acrylates, acrylonitrile, methacrylonitrile, etc., alone or in combination of two or more thereof, and polysiloxane skeletons. Having a macromonomer. Among the macromonomers, a polymer having a glass transition temperature higher than the glass transition temperature of the binder resin is preferable. Particularly, a copolymer macromonomer of styrene and methacrylate and / or acrylate or a polymethacrylate macromonomer Is preferred. When a macromonomer is used, its mixing ratio is usually 0.01 to 10 parts by weight, preferably 0.03 to 5 parts by weight, more preferably 0.05 to 5 parts by weight, based on 100 parts by weight of the polymerizable monomer. 1 part by weight. If the proportion of the macromonomer is too large, the fixability tends to decrease.

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

As the colorant for the color toner, a yellow colorant, a magenta colorant, a cyan colorant and the like can be used. Examples of the yellow colorant include C.I.
I. Pigment Yellow 3, 12, 13, 14, 15,
17, 62, 65, 73, 83, 90, 93, 97, 1
20, 138, 155, 180, 181; Nephtol Yellow S, Hansa Yellow G, C.I. I. Bat yellow and the like.

Examples of the magenta colorant include azo pigments and condensed polycyclic pigments, and more specifically, for example,
C. I. Pigment Red 48, 57, 58, 60, 6
3, 64, 68, 81, 83, 87, 88, 89, 9
0, 112, 114, 122, 123, 144, 14
6, 149, 163, 170, 184, 185, 18
7, 202, 206, 207, 209, 251;
I. Pigment Violet 19 and the like.

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

(5) Molecular weight regulator Examples of the molecular weight regulator include mercaptans such as t-dodecyl mercaptan, n-dodecyl mercaptan and n-octyl mercaptan; halogenated hydrocarbons such as carbon tetrachloride and carbon tetrabromide. And the like.
These molecular weight regulators can be added before the start of polymerization or during the polymerization. The molecular weight modifier is used in an amount of usually 0.01 to 10 parts by weight, preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the polymerizable monomer.

(6) Lubricants and Dispersing Aids For the purpose of, for example, uniformly dispersing the colorant in the toner particles, fatty acids such as oleic acid and stearic acid, fatty acids and Na,
A lubricant such as a fatty acid metal salt composed of a metal such as K, Ca, Mg, Zn or the like; a dispersing aid such as a silane-based or titanium-based coupling agent; and the like may be used. Such a lubricant or dispersant is usually 1/100 based on the weight of the colorant.
It is used at a ratio of about 0 to 1/1.

(7) Charge Control Agent In order to improve the chargeability of the toner, it is preferable to include various positive or negative charge control agents in the monomer composition. Examples of the charge control agent include Bontron N01 (manufactured by Orient Chemical Co., Ltd.), Nigrosine Base EX (manufactured by Orient Chemical Co., Ltd.), Spiro Black TRH
(Hodogaya Chemical Co., Ltd.), T-77 (Hodogaya Chemical Co., Ltd.), Bontron S-34 (Orient Chemical Co., Ltd.), Bontron E-81 (Orient Chemical Co., Ltd.), Bontron E-84 (Orient Chemical Co., Ltd.), Bontron E-89
(Orient Chemical), Bontron F-21 (Orient Chemical), COPY CHRGE NX (Clariant), COPY CHRGE NEG (Clariant), TNS-4-1 (Hodogaya Chemical),
TNS-4-2 (Hodogaya Chemical Co., Ltd.), LR-147
Charge controlling agents such as (manufactured by Nippon Carlit Co., Ltd.);
JP-A-15192, JP-A-3-175456,
Quaternary ammonium (salt) group-containing copolymers described in JP-A-3-243954 and the like;
JP, JP-A-1-217664, JP-A-3-13-1
And a charge control resin such as a sulfonic acid (salt) group-containing copolymer described in US Pat. The charge control agent is used in an amount of usually 0.01 to 10 parts by weight, preferably 0.1 to 7 parts by weight, based on 100 parts by weight of the binder resin or the polymerizable monomer forming the binder resin. .

(8) Release Agent The alkyl alkyl aromatic polycarboxylate used in the present invention also acts as a release agent, so that it is not necessary to use another release agent. Various release agents may be contained for such purposes. Examples of the release agent include low-molecular-weight polyethylene, low-molecular-weight polypropylene, low-molecular-weight polyolefin waxes such as low-molecular-weight polybutylene; low-molecular-weight oxidized polypropylene having low molecular weight, low-molecular-weight terminal-modified polypropylene having a molecular terminal substituted with an epoxy group, and the like. And low-molecular-weight polyethylene block polymers, molecular-end oxidized low-molecular-weight polyethylene, low-molecular-weight polyethylene having a molecular end substituted with an epoxy group, and terminal-modified polyolefin waxes such as these and low-molecular-weight polypropylene block polymers; candelilla, carnauba, rice, Plant waxes such as wood wax and jojoba; petroleum waxes such as paraffin, microcrystalline and petrolactam and modified waxes; mineral waxes such as montan, ceresin and ozokerite Camphor; Other polyfunctional ester compound; synthetic waxes such as Fischer-Tropsch wax and mixtures thereof and the like. These release agents are preferably used in an amount of 0.1 to 20 parts by weight based on 100 parts by weight of the binder resin or the polymerizable monomer forming the binder resin.
It is more preferable to use １５15 parts by weight.

(9) Polymerization initiator As the polymerization initiator, a radical polymerization initiator is suitably used. Specifically, persulfates such as potassium persulfate and ammonium persulfate; 4,4'-azobis (4-cyanovaleric acid), 2,2'-azobis (2-amidinopropane)
Dihydrochloride, 2,2'-azobis-2-methyl-N-1,
1-bis (hydroxymethyl) -2-hydroxyethylpropioamide, 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2'-azobisisobutyronitrile, 1,1'-azobis Azo compounds such as (1-cyclohexanecarbonitrile); isobutyryl peroxide, 2,4-di-chlorobenzoyl peroxide,
Diacyl peroxides such as 3,5,5'-trimethylhexanoyl peroxide; bis (4-t-butylcyclohexyl) peroxydi-carbonate, di-n
-Propylperoxydi-carbonate, di-isopropylperoxydi-carbonate, di-2-ethoxyethylperoxydi-carbonate, di (2-ethylethylperoxy) di-carbonate, di-methoxybutylperoxydi- Peroxydi-carbonates such as carbonate and di (3-methyl-3-methoxybutylperoxy) di-carbonate; (α, α-bis-neodecanylyloxy) diisopropylbenzene, cumylperoxyneodecanoate, 1 1,1 ', 3,3'-Tetramethylbutylperoxyneodecanoate, 1-cyclohexyl-1-methylethylperoxyneodecanoate, t-hexylperoxyneodecanoate, t-butylperoxyneo Decanoate, t-hexyl peroxypivalate, t -Butylperoxypivalate, methylethyl peroxide, di-t-butyl peroxide, acetyl peroxide, dicumyl peroxide, lauroyl peroxide, benzoyl peroxide, t-
Other peroxides such as butylperoxy-2-ethylhexanoate, di-isopropylperoxydicarbonate, di-t-butylperoxyisophthalate, and t-butylperoxyisobutyrate are exemplified. . A redox initiator obtained by combining these polymerization initiators and a reducing agent can also be used.

Of these, an oil-soluble radical initiator soluble in the polymerizable monomer is preferable, and a water-soluble initiator can be used in combination therewith, if necessary. The proportion of the polymerization initiator used is usually 0.1 to 20 parts by weight, preferably 0.3 to 15 parts by weight, based on 100 parts by weight of the polymerizable monomer.
More preferably, it is 0.5 to 10 parts by weight. If the ratio is too small, the polymerization rate is low, and if it is too large, the molecular weight is low, which is not preferable. The polymerization initiator can be added in advance to the monomer composition, but is added to the suspension after the granulation step of the monomer composition in the aqueous dispersion medium for the purpose of avoiding early polymerization. Can also be added. The proportion of the polymerization initiator used is usually about 0.001 to 3% by weight based on the aqueous dispersion medium.

(10) Dispersion Stabilizers The dispersion stabilizers used in the present invention include sulfates such as barium sulfate and calcium sulfate; carbonates such as barium carbonate, calcium carbonate and magnesium carbonate; phosphates such as calcium phosphate; Metal oxides such as aluminum oxide and titanium oxide; metal hydroxides such as aluminum hydroxide, magnesium hydroxide and ferric hydroxide; water-soluble polymers such as polyvinyl alcohol, methyl cellulose and gelatin; anionic surfactants; Surfactants such as nonionic surfactants and amphoteric surfactants; and the like. Of these, metal compounds such as sulfates, carbonates, metal oxides and metal hydroxides are preferred, and colloids of poorly water-soluble metal compounds are more preferred. In particular, colloids of poorly water-soluble metal hydroxides are preferred because they can narrow the particle size distribution of toner particles and improve the sharpness of images.

The colloid of the poorly water-soluble metal compound is not limited by the production method, but the colloid of the poorly water-soluble metal hydroxide obtained by adjusting the pH of the aqueous solution of the water-soluble polyvalent metal compound to 7 or more. In particular, a colloid of a poorly water-soluble metal hydroxide formed by a reaction of a water-soluble polyvalent metal compound with an alkali metal hydroxide in an aqueous phase is preferable. The colloid of the poorly water-soluble metal compound has a number particle size distribution D ₅₀ (50% cumulative value of the number particle size distribution) of 0.5 μm or less,
₉₀ (90% cumulative value of the number particle size distribution) is preferably 1 μm or less. If the particle size of the colloid is too large, the stability of polymerization is lost, and the storage stability of the toner is reduced.

The dispersion stabilizer is used in a proportion of usually 0.1 to 20 parts by weight, preferably 0.3 to 10 parts by weight, based on 100 parts by weight of the polymerizable monomer. If the use ratio is too small, it is difficult to obtain sufficient polymerization stability, and a polymer aggregate is easily generated. Conversely, if the use ratio is too large, the particle size distribution of the toner particles is widened due to the increase in the fine particles, and the viscosity of the aqueous solution is increased to lower the polymerization stability.

(11) Production Method of Polymerized Toner A polymerized toner contains at least a polymerizable monomer, a colorant, and an alkyl alkyl aromatic polycarboxylate in an aqueous dispersion medium containing a dispersion stabilizer. The resulting polymerizable monomer mixture can be obtained as colored polymer particles by suspension polymerization. More specifically, a polymerizable monomer, a colorant, an aromatic polycarboxylic acid alkyl ester, a charge controlling agent, and the like are mixed and uniformly dispersed using a bead mill or the like to obtain an oily mixed solution. A hydrophilic monomer composition is prepared. Next, the polymerizable monomer composition is charged into an aqueous dispersion medium containing a dispersion stabilizer, and stirred with a stirrer. After the particle size of the droplets of the polymerizable monomer composition becomes constant by stirring, a polymerization initiator is charged and the polymerization initiator is transferred into the droplets of the polymerizable monomer composition. Next, the droplets of the polymerizable monomer composition are granulated into finer droplets using a mixing device having a high shearing force. In this manner, after granulation into fine droplets having a particle size substantially comparable to the particle size of the polymerization method toner to be produced, polymerization is usually performed at a temperature of 30 to 200 ° C.

The method for forming the core-shell structure is as follows. In the case of a polymerization toner, the colored polymer particles are used as core particles,
A method is preferable in which a polymerizable monomer for shell is polymerized in the presence of the core particle to form a polymer layer (shell) on the surface of the core particle. In this case, a polymerizable monomer capable of producing a polymer having a glass transition temperature higher than the glass transition temperature of the polymer component constituting the colored polymer particles of the core is used as the polymerizable monomer for the shell. By doing so, the blocking resistance (preservability) of the polymerized toner can be improved. As the polymerizable monomer for the core, those capable of producing a polymer having a glass transition temperature of usually 60 ° C. or lower, preferably about 40 to 60 ° C. are suitable. As the polymerizable monomer for the shell, a polymer having a glass transition temperature higher than the glass transition temperature of the polymer component forming the core by 10 ° C. or higher, preferably 20 ° C. or higher, more preferably 30 ° C. or higher can be produced. Those are preferred. The glass transition temperature of the polymer formed from the polymerizable monomer for shell is usually more than 50 ° C and 120 ° C or less, preferably more than 60 ° C and 110 ° C or less,
More preferably, it is 80 to 105 ° C. The glass transition temperature is a value calculated from the type and the use ratio of each monomer according to a conventional method.

When a water-soluble polymerization initiator is added when the polymerizable monomer for shell is added to the polymerization reaction system, polymer particles having a core-shell type structure are easily formed. Examples of the water-soluble polymerization initiator include persulfates such as potassium persulfate and ammonium persulfate; 4,4′-azobis (4-cyanovaleric acid), 2,2′-azobis (2-amidinopropane) dihydrochloride, 2,2'-azobis-2-methyl-N-
An azo initiator such as 1,1'-bis (hydroxymethyl) -2-hydroxyethylpropioamide; a combination of an oil-soluble initiator such as cumene peroxide and a redox catalyst; The amount of the water-soluble polymerization initiator is usually 0.001 to 3% by weight based on the aqueous dispersion medium.

(12) Toner for developing an electrostatic image The volume average particle diameter of the toner for developing an electrostatic image (including those having a core-shell structure) of the present invention is usually 1 to 12 μm, preferably 2 to 11 μm. Preferably it is 3 to 10 μm. To obtain high resolution, the volume average particle diameter of the toner can be reduced to preferably 2 to 9 μm, more preferably 3 to 8 μm, and particularly preferably 3 to 7 μm.
The particle size distribution represented by the volume average particle size (dv) / number average particle size (dp) of the toner of the present invention is usually 1.7 or less, preferably 1.5 or less, more preferably 1.4 or less. Especially preferably, it is 1.3 or less. If the volume average particle size of the toner is too large, the resolution tends to decrease. If the particle size distribution of the toner is large, the ratio of the toner having a large particle size increases, and the resolution tends to be reduced.

The toner of the present invention has a sphericity represented by a ratio (dl / ds) of a major axis (dl) and a minor axis (ds), preferably from 1 to 1.3, more preferably from 1 to 1.3. Preferably, the two are substantially spherical. When a substantially spherical toner is used as the non-magnetic one-component developer, the transfer efficiency of the toner image on the photosensitive member to the transfer material is improved. Such a spherical toner can be obtained by a suspension polymerization method.

In the toner having a core-shell structure, the average thickness of the shell is usually 0.001 to 1.0 μm, preferably 0.003 to 0.5 μm, more preferably 0.03 to 0.5 μm.
05 to 0.2 μm. If the shell thickness is too large, the fixability decreases, and if it is too small, the storage stability decreases. When the core particle diameter of the polymerization method toner and the thickness of the shell can be observed by an electron microscope, it can be obtained by directly measuring the size and the shell thickness of the particles randomly selected from the observation photograph, When it is difficult to observe the core and the shell with a microscope, it can be calculated from the particle size of the core particles and the amount of the polymerizable monomer forming the shell.

The toner of the present invention has a DSC curve measured by a differential scanning calorimeter.
It is preferable that the peak shows the maximum endothermic peak in the region. If the maximum endothermic peak temperature of the toner is too high, the low-temperature fixability tends to decrease, and if it is too low, the storage stability tends to deteriorate.

(13) Non-magnetic one-component developer When the toner of the present invention is used as a non-magnetic one-component developer, an external additive can be mixed as needed.
Examples of the external additive include inorganic particles and organic resin particles acting as a fluidizing agent, an abrasive, and the like.

Examples of the inorganic particles include silicon dioxide (silica), aluminum oxide (alumina), titanium oxide, zinc oxide, tin oxide, barium titanate, and strontium titanate. As the organic resin particles, methacrylic acid ester polymer particles, acrylic acid ester polymer particles, styrene-methacrylic acid ester copolymer particles, styrene-acrylic acid ester copolymer particles, the core is a shell of a methacrylic acid ester copolymer Are core-shell particles formed of a styrene polymer.

Of these, inorganic oxide particles are preferred, and silicon dioxide is particularly preferred. The surface of the inorganic fine particles can be subjected to a hydrophobic treatment, and silicon dioxide particles subjected to the hydrophobic treatment are particularly preferable. The external additives may be used in combination of two or more types. When the external additives are used in combination, a method of combining inorganic particles having different average particle diameters or inorganic particles and organic resin particles is preferable. . The amount of the external additive is not particularly limited, but is usually 0.1 to 6 parts by weight based on 100 parts by weight of the toner particles. In order for the external additive to adhere to the toner particles, the toner and the external additive are usually stirred in a mixer such as a Henschel mixer.

[0056]

The present invention will now be described more specifically with reference to examples and comparative examples. Parts and percentages are by weight unless otherwise specified. Physical properties and characteristics were evaluated by the following methods. (1) Dissolution amount (g / 100 g ST; 35 ° C.) The amount of the aromatic polycarboxylic acid alkyl ester dissolved in styrene is determined by the amount of the polyfunctional ester compound dissolved in 100 g of styrene maintained at 35 ° C. (g / 100 gS
T) was measured.

(2) Acid value (mgKOH / g) Measured according to JIS K-1557- 1970. About 50 g of a sample was precisely weighed in a 300 ml beaker, 128 ml of acetone (80 v / v%) was added thereto, and after dissolution, the solution was subjected to potentiometric titration with a 0.1N NaOH aqueous solution using a PH meter to obtain a solution. Set the inflection point of the titration curve as the end point. The acid value is determined from the following equation. A = [5.61 × (BC) × f] / S where A: acid value (mg KOH / g) B: amount of 0.1N sodium hydroxide aqueous solution (ml) required for titration of the sample C: Amount of 0.1N sodium hydroxide aqueous solution required for titration in blank test (ml) f: Factor of 0.1N sodium hydroxide aqueous solution S: Amount of sample (g)

(3) Hydroxyl value (mgKOH / g) The hydroxyl value was measured in accordance with the hydroxyl value used in JIS K-1557-970 (Testing method for ether for polyurethane).
Specifically, a sample amount calculated from the following formula was weighed to 1 mg, placed in a 250 ml triangular flask with a condenser, and a phthalic anhydride pyridine solution (1.4 W / V) was added.
%) Is added with a pipette, immersed in a constant temperature bath at 98 ° C. ± 2 ° C., and heated for 2 hours. After cooling, pipette 50 ml of N / 2 sodium hydroxide solution. Next, a pyridine solution of phenolphthalene (1 W / V%) as an indicator
Add 10 drops, titrate with N / 2 sodium hydroxide solution,
The point holding the red color is the end point. The hydroxyl value is determined from the following equation. Sample collection amount: [56 × (6-7)] / hydroxyl value H = [28.05 × (BA) × f] / S + acid value where: H: hydroxyl value (mgKOH / g) A: Amount of aqueous solution of N / 2 sodium hydroxide required for titration of sample (ml) B: Amount of aqueous solution of N / 2 sodium hydroxide required for titration of blank test (ml) f: Sodium hydroxide of N / 2 Factor of aqueous solution S: Amount of sample (g)

(4) Maximum Endothermic Peak Temperature (° C.) The maximum endothermic peak temperature of the aromatic polycarboxylic acid alkyl ester and the toner was measured in accordance with ASTM D3418-82. More specifically, the sample was heated at a heating rate of 10 ° C./min using a differential scanning calorimeter, and the temperature at the maximum endothermic peak of the DSC curve obtained in the process was measured. As a differential scanning calorimeter, "S" manufactured by Seiko Denshi Kogyo
SC5200 "was used.

(5) Droplet Particle Size of the Polymerizable Monomer Composition The volume average particle size (dv) of the droplet, and the particle size distribution, that is, the volume average particle size (dv) and the number average particle size (dp) Ratio (dv /
dp) is a particle size distribution analyzer (SALD2000A type,
(Manufactured by Shimadzu Corporation). In the measurement by this particle size distribution measuring device, the refractive index = l. 55-0.
20i, ultrasonic irradiation time = 5 minutes.

(6) Volume average particle size (dv) and particle size distribution (dv / dp) Volume average particle size (dv) of polymer particles, and volume average particle size (dv) and number average particle size (dp) And the ratio (dv / dp)
Was measured by a multisizer (Beckman Coulter, manufactured by Coulter, Inc.). The measurement by the multisizer is as follows: aperture diameter = 100 μm,
Medium = Isoton II, concentration = 10%, number of measured particles = 50
The test was performed under the conditions of 000 pieces.

(7) Shell thickness Since the thickness of the shell was small, it was calculated using the following equation. x = r (1 + s / 100ρ) ^1/3 -r where r = radius of core particle size (volume particle size of multisizer: μm) before addition of shell monomer, x = shell thickness (μm), s = The number of parts of the shell monomer added to 100 parts by weight of the core monomer, ρ = the density of the shell polymer (g /
cm ³ ). ρ was 1.0 g / cm ³ , and the value of x was calculated.

(8) Fixing Temperature (° C.) A commercially available non-magnetic one-component developing system printer (printing speed =
A fixing test was performed using a printer modified so that the temperature of the fixing roll portion (16 sheets / min) could be changed. The fixing test was performed by changing the temperature of the fixing roll of the modified printer, measuring the fixing rate of the developer at each temperature, and determining the relationship between the temperature and the fixing rate. The retention rate is
When the temperature was changed, the fixing roll was allowed to stand for 5 minutes or more in order to stabilize the temperature, and then calculated from the ratio of the image density before and after the tape peeling operation of the solid black region on the test paper printed by the modified printer. That is, the image density before peeling the tape is the ID, and the image density after peeling the tape is I.
Assuming that after D, the fixing rate can be calculated from the following equation. Fixing rate (%) = (after ID / before ID) × 100 Here, the tape peeling operation is to attach an adhesive tape (Scotch Mending Tape 810-3-18 manufactured by Sumitomo 3M Limited) to the measurement portion of the test paper, This is a series of operations in which the adhesive tape is pressed and adhered at a constant pressure, and then the adhesive tape is peeled in a direction along the paper at a constant speed. The image density was measured using a Macbeth reflection image densitometer. In this fixing test, the fixing roll temperature corresponding to a fixing rate of 80% was defined as the fixing temperature of the developer.

(9) Offset Temperature (° C.) In the same manner as in the fixing test, the fixing temperature was changed to print solid black, and the temperature of the fixing roll when the offset occurred was defined as the offset temperature. (10) Storage (%) The developer is placed in a sealable container, and after sealing, the container is immersed in a thermostatic water bath set at a temperature of 50 ° C. After 72 hours, the container is taken out of the thermostatic bath, and the developer in the container is transferred onto a 42-mesh sieve. At this time, the developer is gently taken out of the container and carefully transferred to the sieve so as not to destroy the aggregated structure of the developer in the container. After the sieve was vibrated for 30 seconds under the condition of the vibration intensity scale 4.5 using the above-mentioned powder measuring machine, the weight of the developer remaining on the sieve was measured, and the result was regarded as the weight of the cohesive developer. . The weight ratio (% by weight) of the aggregation developer to all the developers was calculated. The measurement was performed three times for one sample, and the average value was used as an index of the storage stability.

(11) Environmental Dependence of Image Quality Using the above-described modified printer, a developer to be evaluated is put into a developing device of the printer, and a temperature of 35 ° C. and a relative humidity of 80 are used.
% And then print continuously from the beginning
When the print density is 1.3 or more with a reflection densitometer (manufactured by Macbeth),
In addition, the number of continuous printed sheets capable of maintaining an image quality of 15% or less of fog in the non-image area on the photoreceptor measured by a whiteness meter (manufactured by Nippon Denshoku) was examined, and environmental dependency was evaluated based on the following criteria. Fog is applied to the non-image area on the photoreceptor with an adhesive tape (Scotch Mending Tape 810-3-1 manufactured by Sumitomo 3M Limited).
8) was deposited and examined. Specifically, an adhesive tape is stuck on white paper, and whiteness A is measured. On the other hand, after attaching the adhesive tape to the non-image part of the photoreceptor after printing, peel off,
This is affixed to white paper, and whiteness B is measured. Fog can be calculated by the following equation. In addition, continuous printing is performed at 5% printing density, and printing density and fog are 5%.
The inspection was performed every 00 sheets. Fog (%) = [(A−B) / A] × 100 A: No problem in image characteristics even after printing 10000 sheets B: No problem in image characteristics even when printing from 7500 to 9500 sheets C : No problem in image characteristics even when printing up to 5,000 to 7000 sheets. D: Problems in image characteristics with 4,500 sheets or less.

Example 1 (1) Preparation of Monomer Composition 80.5 parts of styrene and n-butyl acrylate
5 parts polymerizable monomer (calculated T
g = 55 ° C.) 100 parts, carbon black (Mitsubishi Chemical Corporation, trade name “# 25”) 6 parts, charge control agent (Hodogaya Chemical Co., trade name “Spiron Black TRH”) 1 part, divinylbenzene 0 .4 parts, t-dodecyl mercaptan 1.0 part, and polymethacrylate macromonomer (manufactured by Toa Gosei Chemical Industry Co., Ltd., trade name: AA6, Tg = 9)
4 ° C.) After stirring and mixing 0.5 part with an ordinary stirring device,
It was uniformly dispersed by a media type disperser. Here, as a polyfunctional ester compound, 10 parts of dibehenyl phthalate [dissolution amount in styrene = 15 (g / 100 g ST; 35 ° C.) or more] was added, mixed, and dissolved to prepare a monomer composition. All preparations of the monomer composition were performed at room temperature.

(2) Preparation of aqueous dispersion medium At room temperature, 9.5 parts of magnesium chloride (water-soluble polyvalent metal salt) was dissolved in 250 parts of ion-exchanged water, and 50 parts of ion-exchanged water was mixed with sodium hydroxide (water). Alkali metal oxide)
An aqueous solution in which 5.8 parts are dissolved is gradually added with stirring,
A dispersion of magnesium hydroxide colloid (poorly water-soluble metal hydroxide colloid) was prepared. All of the dispersions were prepared at room temperature. SALD
When measured with a particle size distribution analyzer (Shimadzu Corporation), D ₅₀
(50% cumulative value of number particle size distribution) is 0.36 μm, and D
₉₀ (90% cumulative value of the number particle size distribution) was 0.80 μm.

(3) Granulation Step The monomer composition prepared in the above (1) is added to the magnesium hydroxide colloid dispersion prepared in the above (2) at room temperature and stirred until the droplets are stabilized. After that, 5 parts of t-butyl peroxy-2-ethylhexanoate (trade name “Perbutyl O” manufactured by NOF Corporation) was added as a polymerization initiator. Then, using Ebara Milder (trade name “MDN303V”, manufactured by Ebara Corporation), 15,000 rpm
The mixture was stirred with high shear at a rotation speed of m for 10 minutes to granulate fine droplets of the monomer composition.

(4) Suspension polymerization The aqueous dispersion medium (suspension) of the monomer composition granulated in the above (3) is charged into a reactor equipped with a stirring blade, and the polymerization reaction is carried out at 90 ° C. Started. After continuing the polymerization reaction for 10 hours,
The polymerization reaction was terminated by water cooling. While stirring the aqueous dispersion of polymer particles obtained by the polymerization reaction at room temperature, sulfuric acid is added to adjust the pH of the system to 4 or less, and acid washing (25 ° C., 10 ° C.).
Min) and water was separated by filtration. Thereafter, 500 parts of ion-exchanged water was newly added to reslurry, and water washing was performed. After that, dehydration and water washing were repeated several times at room temperature. Next, the solid content was separated by filtration, and dried at 40 ° C. for 24 hours in a drier to collect polymer particles. The volume average particle diameter of the obtained polymer particles (d
v) was 6.8 μm, and the volume average particle diameter (dv) / number average particle diameter (dp) was 1.22. In the DSC measurement, a maximum endothermic peak appeared at 57 ° C.

(5) Preparation of Developer 100 parts of the polymer particles obtained in (4) above were subjected to hydrophobic treatment at room temperature with colloidal silica (trade name “RX-200” manufactured by Nippon Aerosil Co., Ltd.) 0.6 Was added and mixed using a Henschel mixer to prepare a non-magnetic one-component developer.

(6) Developer Characteristics The fixing temperature was measured using the developer obtained in the above (5) and found to be 145 ° C. In addition, the environmental temperature dependence of the offset temperature, storage stability, and image quality of the developer was examined. Table 1 shows the results.

Example 2 A yellow pigment (trade name "toner yellow HG VP2155", manufactured by Clariant) instead of carbon black as a colorant:
C. I. Pigment Yellow 180), and distearyl isophthalate [dissolved amount in styrene = 15 as an aromatic polycarboxylic acid alkyl ester]
(G / 100 g ST; 35 ° C. or more)], and a polymerization toner and a developer were obtained in the same manner as in Example 1. When the fixing temperature was measured using the obtained developer, it was 135 ° C. Table 1 shows the results.

Example 3 The procedure of Example 1 was repeated except that dibehenyl isophthalate [dissolved amount in styrene = 15 (g / 100 g ST; 35 ° C.) or more] was used as the alkyl alkyl aromatic polycarboxylate. Thus, a polymerization toner and a developer were obtained. When the fixing temperature was measured using the obtained developer, it was 140 ° C. Table 1 shows the results.

Example 4 Distearyl monobehenyl trimellitate [dissolved amount in styrene = 15 (g / 100 gS) as an aromatic polycarboxylic acid alkyl ester
T; 35 ° C. or higher), and a polymerization toner and a developer were obtained in the same manner as in Example 1. When the fixing temperature was measured using the obtained developer, it was 140 ° C. Table 1 shows the results.

Example 5 (1) Synthesis of Core Particles Distearyl phthalate [dissolved amount in styrene = 15 (g / 1) as an aromatic polycarboxylic acid alkyl ester
00gST; 35 ° C. or more), except that steps (1) to (3) of Example 1 were used. However, the process
In (3), 15,000 rpm using Ebara Milder
The mixture was vigorously stirred at a rotational speed of m for 30 minutes to granulate a droplet of the monomer composition. The aqueous dispersion medium of the granulated monomer composition was put into a reactor equipped with a stirring blade, a polymerization reaction was started at 60 ° C., and when the polymerization conversion reached almost 100%, sampling was performed. , Core particles (colored polymer particles)
Was measured. As a result, the volume average particle size (dv) was 6.2 μm, and the volume average particle size (dv) / number average particle size (dp) was 1.23.

(2) Shell formation At room temperature, methyl methacrylate (calculated Tg = 105 ° C.)
2 parts and 30 parts of water are finely dispersed by an ultrasonic emulsifier,
An aqueous dispersion of a polymerizable monomer for shell was obtained. The particle size of the droplets of the polymerizable monomer for shell and the obtained droplet was measured with SALD particle diameter distribution measuring instrument, D ₉₀ was 1.6 [mu] m. An aqueous dispersion of the polymerizable monomer for shell and a water-soluble initiator [trade name “VA-086” manufactured by Wako Pure Chemical Industries;
0.2 parts of 2'-azobis [2-methyl-N- (2-hydroxyethyl) -propionamide] was added to 65 parts of distilled water.
The solution dissolved in the part was placed in a reactor and polymerization was continued for 4 hours. Then, the reaction was stopped to obtain an aqueous dispersion of polymer particles having a pH of 9.5.

The aqueous dispersion of polymer particles having a core-shell structure obtained above was acid-washed (25 ° C., 10 minutes) at room temperature with stirring while adjusting the pH of the system to 4 or less with sulfuric acid. After separating water by filtration, 500 parts of ion-exchanged water was newly added to reslurry and washed with water. Thereafter, dehydration and water washing are repeated several times at room temperature, and the solid content is separated by filtration.
Drying was performed at ℃ for 24 hours to obtain polymer particles.

The polymer particles have a volume average particle size (dv)
Was 6.7 μm, and volume average particle diameter (dv) / number average particle diameter (dp) was 1.21. The shell thickness calculated from the amount of the polymerizable monomer for the shell and the particle size of the core particles is:
It was 0.02 μm. The endothermic peak temperature of the polymer particles was 50 ° C.

(3) Developer 100 parts of the polymer particles having the core-shell structure are
At room temperature, 0.6 parts of colloidal silica (trade name “RX-200” manufactured by Nippon Aerosil Co., Ltd.), which had been subjected to hydrophobic treatment, was added and mixed using a Henschel mixer to prepare a developer. When the fixing temperature was measured using the thus obtained developer, it was 140 ° C. Table 1 shows the results.

COMPARATIVE EXAMPLE 1 Dimyristyl phthalate [alkyl number of carbon atoms = 14; dissolution amount in styrene = 15]
(G / 100 g ST; 35 ° C. or more)], and a polymerization toner and a developer were obtained in the same manner as in Example 1. When the fixing temperature was measured using the obtained developer, it was 125 ° C. This developer has poor storage stability, and
After storage at 72 ° C. for 72 hours, the whole was solidified. Table 1 shows the results
Shown in

[0081]

[Table 1]

[0082]

According to the present invention, the fixing temperature is low, energy can be saved, printing and copying can be performed at high speed, and colorization can be achieved. Provided is a toner for developing an electrostatic image, which is capable of forming good, high-resolution, and high-quality images.

Claims (2)

[Claims] 1. A toner for developing an electrostatic image containing at least a binder resin, a colorant and a polyfunctional ester compound, wherein the polyfunctional ester compound is an aromatic polyvalent compound having an alkyl moiety having at least 15 carbon atoms. A toner for developing an electrostatic image, which is a carboxylic acid alkyl ester. 2. The aromatic polycarboxylic acid alkyl ester according to claim 1, wherein the DSC curve measured by a differential scanning calorimeter shows a maximum endothermic peak in the range of 50 to 80 ° C. when the temperature is raised. An electrostatic image developing toner.