JP2001147550A - Electrostatic charge image developing toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrostatic charge image developing toner for low temperature fixing, adaptable to energy saving, high-speed printing and copying and color printing and copying, excellent in preservability and fluidity and capable of forming a good image with high resolution. SOLUTION: The electrostatic charge image developing toner contains at least a bonding resin, a colorant and a polyfunctional ester compound having (a) >=5 ester bonds in one molecule, (b) a molecular weight of >=2,000, (c) a solubility of >=5 g/100 g styrene measured at 35 deg.C and (d) an acid value of <=2 mgKOH/g.

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 is 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 and to improve fixability such as lowering of a fixing temperature without impairing storability.

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 and copying speeds. 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 image developing toner, there is a method of responding to such a demand from an image forming apparatus, for example, a method of lowering a glass transition temperature of a 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, electrophotographic color printing and color copying techniques 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, it is necessary to design the melt viscosity of the color toner near the fixing temperature to be lower than that of the conventional color toner so as to facilitate the melting. 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 an electrostatic image having good low-temperature fixability, a low-softening point material 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 polymerization toner, toner particles contain a high softening point resin (A) and a low softening point substance (B), and are mainly composed of a high softening point resin. 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 coloring agent, 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, in a toner containing at least a binder resin, a colorant, and a wax, a toner containing a specific ester compound as the wax. 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 during fixing exists in 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 this goes against energy reduction. I do.

[0013]

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 charge image capable of forming high resolution and good image quality.

The present inventor has 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. In the toner for image development, the polyfunctional ester compound has 5 or more ester bonds in a molecule, has a molecular weight of 2,000 or more, a solubility of 5 g or more in 100 g of styrene measured at 35 ° C., and an acid value of It has been found that the object can be achieved by including a polyfunctional ester compound of 2 mgKOH / g or less. 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.

[0015]

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 comprises (a) a molecule Having 5 or more ester bonds in it, (b) a molecular weight of 2,000 or more, and (c) a solubility of 5 g or more in 100 g of styrene measured at 35 ° C., and
(d) An electrostatic image developing toner having an acid value of 2 mgKOH / g or less is provided.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Polyfunctional ester compound The polyfunctional ester compound used in the present invention has 5
It is a polyfunctional ester compound having two or more ester bonds (ester groups). The number of ester bonds in the molecule is
The number is preferably 5 to 14, more preferably 6 to 12, particularly preferably 8 to 10. The molecular weight of the polyfunctional ester compound used in the present invention is 2,000 or more, preferably 2,000 to 6,000, more preferably 2,000.
-4000, particularly preferably 2500-3500. If the number of ester bonds in the polyfunctional ester compound is small or the molecular weight is too low, it is difficult to lower the fixing temperature sufficiently, and the offset resistance becomes insufficient. In particular, when the molecular weight of the polyfunctional ester compound is too low, the melting point of the polyfunctional ester compound itself becomes low, and the polyfunctional polyester compound easily bleeds from the toner during storage of the toner or in a high-temperature environment in a toner box of a developing device. As a result, the toner may be aggregated, or crystals of the bleed-out polyfunctional ester compound may grow large. Crystals of the polyfunctional ester compound cause toner filming on the surface of the photoreceptor or the like.

The solubility of the polyfunctional ester compound used in the present invention in styrene is determined by the amount dissolved in 100 g of styrene measured at 35 ° C. (g / 100 g ST; 35 ° C.).
Needs to be 5 g or more. This dissolution amount is preferably at least 10 g, more preferably at least 15 g, particularly preferably at least 20 g. If the amount of the polyfunctional ester compound dissolved in styrene at 35 ° C. is too small, the solubility of the polyfunctional ester compound in a polymerizable monomer containing styrene as a main component generally decreases. Therefore, the content of the polyfunctional ester compound in the toner is insufficient, and it is difficult to sufficiently lower the fixing temperature. On the other hand, if this 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 polyfunctional ester compound in the polymerizable monomer. Moreover, even if such a polyfunctional ester compound 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 polyfunctional ester compound used in the present invention must be 2 mgKOH / g or less. The acid value is preferably 1.5 mgKOH / g or less, more preferably 1.3 mgKOH / g or less. If the acid value of the polyfunctional ester compound is too high, it has an adverse effect when granulating the droplets of the monomer composition in the aqueous dispersion medium, and granulates droplets having a uniform and stable particle size distribution. It becomes difficult. In addition, a toner containing a polyfunctional polyester compound having a high acid value has unstable charging properties under high temperature and high humidity, and it is difficult to obtain a sufficient image density.

The polyfunctional ester compound used in the present invention has the above-mentioned various properties, and has a DSC curve measured by a differential scanning calorimeter.
It is preferable that the peak shows the maximum endothermic peak in the region. A polyfunctional ester compound having a maximum endothermic peak temperature of 50 to 80 ° C. is a substance having a low softening point and can sufficiently contribute to low-temperature fixability of a toner. The maximum endothermic peak temperature is preferably 55 to 70 ° C, particularly preferably 59 to 70 ° C.
65 ° C.

Preferred examples of the polyfunctional ester compound used in the present invention include a perfect ester compound of a pentacarboxylic or more polyhydric alcohol and a carboxylic acid.
When the polyhydric alcohol has 4 or less functional groups, the solubility of the ester compound in the polymerizable monomer tends to decrease. In particular, when the molecular weight of the polyhydric alcohol is 100 or less, the tendency becomes strong. The molecular weight of the polyhydric alcohol is preferably 1500 or less. A polyfunctional ester compound using a polyhydric alcohol having a molecular weight that is too large tends to reduce the releasing effect of a carboxylic acid component (particularly, a fatty acid component).

Examples of the polyhydric alcohol having five or more functional groups include dehydration condensates of glycerin, saccharides and dehydration condensates thereof. If the dehydrated condensate of a saccharide is a polyhydric alcohol having five or more functional groups, the saccharide before condensation may have four or less functional groups. Specifically, examples of the pentafunctional or higher polyhydric alcohol include triglycerin, tetraglycerin, pentaglycerin, hexaglycerin, heptaglycerin, octaglycerin, nonaglycerin, decaglycerin, pentadecaglycerin, eicosaglycerin,
Dehydration condensates of glycerin such as triacontaglyserin; petaerythritol, erythritol, D-erythrose, arabinose, D-xylulose, α-D-xylose, 2-deoxy-D-ribose, α-D-lyxose, D-ribulose, D-arabitol, ribitol, β-D-altrose, β-D-allose, α-D
-Galactose, β-D-galactose, α-L-galactose, α-D-quinobose, α-D-glucose,
β-D-glucose, L-sorbose, D-tagatose, α-D-talose, D-fucose, α-D-fucose, α-L-fucose, D-psicose, D-fructose, D-mannose, α- D-mannose, α-L-
Rhamnose, D-inositol, myo-inositol, galactitol, D-glycitol, D-mannitol, D-altro-heptulose, D-manno
-Heptulose, D-altro-3-heptulose,
D-glycero-D-galacto-heptyltol, D-galacto-D-galacto-octitol, D-glycero-D-manno-octulose, D-erythro-L-guulo-nonulose, agarobiose, α-genthiolose, sucrose u ), Β-cellobiose, β-maltose, α-lactose, raffinose, α-cyclodextrin, β-cyclodextrin and the like, or dehydration condensates thereof. Among these, hexaglycerin, tripentaerythritol (a dehydrated condensate of pentaerythritol), and sucrose are preferred.

The carboxylic acid usually has 10 to 10 carbon atoms.
30 carboxylic acids are preferred, preferably 13 to 25. Such carboxylic acids include capric acid, lauric acid, myristic acid, palmitic acid, stearic acid,
Saturated higher fatty acids such as arachinic acid, behenic acid, and lignoceric acid; higher unsaturated fatty acids such as gadrenic acid, erucic acid, and ceracoleic acid; benzoic acid, a para-substituted alkyl benzoic acid having 1 to 30 carbon atoms, and 1 to 30 carbon atoms Aromatic carboxylic acids such as para-substituted alkoxybenzoic acid;

In the polyfunctional ester compound used in the present invention, the carboxylic acid to be condensed with a pentafunctional or higher functional alcohol may be one kind or a combination of two or more kinds. The polyfunctional ester compound obtained by combining several carboxylic acids has reduced crystallinity,
This is preferable because the amount of heat required for melting at the time of fixing the toner is reduced. When a carboxylic acid is used in combination, the difference between the maximum value and the minimum value of the number of carbon atoms in a plurality of carboxylic acids is 16 or less,
It is desirable to select the value to be preferably 10 or less.

Preferred examples of the polyfunctional ester compound used in the present invention include sucrose octapalmitate, sucrose octastearate, sucrose octabehenate, hexaglycerin octastearate, hexaglycerin octabehenate, hexaglycerin tetra Examples include stearate tetrabehenate and hexaglycerin hexastearate dibehenate. In particular, in the present invention, hexaglycerin octabehenate, hexaglycerin tetrastearate tetrabehenate, a polyfunctional ester compound obtained using several carboxylic acids such as hexaglycerin hexastearate dibehenate It is preferably used.

The proportion of the polyfunctional ester compound used is determined by the binder resin of the toner or the polymerizable monomer 1 forming the binder resin.
With respect to 00 parts by weight, usually 0.1 to 40 parts by weight, preferably 1 to 30 parts by weight, more preferably 5 to 20 parts by weight,
Particularly preferably, it is 7 to 15 parts by weight. If the proportion of the polyfunctional ester compound is too small, it becomes difficult to obtain a toner having excellent low-temperature fixability. If the proportion of the polyfunctional ester compound is too large, the offset resistance is reduced and toner filming on the surface of the photoreceptor tends 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 polyfunctional ester compound. Instead, 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 may be a toner having a core-shell structure in which a resin coating layer is formed on the surface of colored particles (capsule toner). 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.

A polymerization toner by suspension polymerization is prepared by suspending a monomer composition containing at least a polymerizable monomer, a colorant, and a polyfunctional ester compound in an aqueous dispersion medium containing a dispersion stabilizer. It can be obtained by polymerization.
The polymer formed by polymerizing the polymerizable monomer becomes the binder resin. The polymerization 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. Specifically, in an aqueous dispersion medium containing a dispersion stabilizer, at least a polymerizable monomer, a coloring agent, and a monomer composition containing a polyfunctional ester compound were obtained by suspension polymerization. It can be obtained by using a colored particle as a core and subjecting the polymerizable monomer for shell to suspension polymerization in the presence of the core.
The polymer layer formed by polymerizing the shell monomer becomes the resin coating layer. In the monomer composition, if necessary, a crosslinkable monomer, a macromonomer, a molecular weight modifier, a charge control agent,
Various additives such as general-purpose release agents, lubricants and dispersing aids can be included.

(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 The use of a crosslinkable monomer and / or a 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 the preservability, the anti-offset property and the low-temperature fixing property. 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 a polymer obtained by polymerizing styrene, a styrene derivative, a methacrylate ester, an acrylate ester, acrylonitrile, methacrylonitrile, or a mixture of two or more thereof, and a polysiloxane skeleton. 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 a colorant for a 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. More specifically, for example, C.I. I. Pigment Red 48, 57, 58, 6
0, 63, 64, 68, 81, 83, 87, 88, 8
9, 90, 112, 114, 122, 123, 144,
146, 149, 163, 170, 184, 185, 1
87, 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. More specifically, for example, C.I. 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
(Manufactured by Orient Chemical Company), Bontron F-21 (manufactured by Orient Chemical Company), COPY CHRGE NX VP4
34 (manufactured by Clariant), COPY CHRGEN
EG VP2036 (manufactured by Clariant), TNS-4
Charge control agents such as -1 (manufactured by Hodogaya Chemical Co., Ltd.), TNS-4-2 (manufactured by Hodogaya Chemical Co., Ltd.), and LR-147 (manufactured by Nippon Carlit Co.); JP-A-11-15192, JP-A-3-175456 And quaternary ammonium (salt) group-containing copolymers described in JP-A-3-243954, JP-A-3-243954, and JP-A-1-217.
Charge control resins such as sulfonic acid (salt) group-containing copolymers described in JP-A-46464 and JP-A-3-15858;
Etc. can be used. 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.
Used in parts by weight.

(8) Release Agent Since the polyfunctional ester compound used in the present invention also acts as a release agent, it is not necessary to use a release agent.
If desired, various release agents may be added for the purpose of preventing offset or the like. 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 Box; synthetic waxes such as Fischer-Tropsch waxes; 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 1 to 15 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 a 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 and a D ₉₀
(90% cumulative value of the number particle size distribution) is preferably 1 μm or less. If the colloid particle size becomes too large,
The stability of the 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) 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) between 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 a 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 method of forming the core-shell structure is as follows. In the case of a polymerization method toner, the colored particles are used as core particles, and a polymerizable monomer for shell is polymerized in the presence of the core particles to overlap the surface of the core particles. A method for forming a coalesced layer (shell) ( in situ polymerization method) is preferred.

According to the DSC curve measured by the differential scanning calorimeter, the toner of the present invention exhibits a temperature of 50 to 80 ° C.
And the melting enthalpy ΔH at that time is preferably 1 to 50 J / g. If the maximum endothermic peak temperature of the toner is too high, it does not contribute to the plasticization of the binder resin component at the time of fixing, and the low-temperature fixability decreases.On the contrary, if the maximum endothermic peak temperature is too low, the storage stability deteriorates. There is a tendency. If the melting enthalpy ΔH is too large, the crystallinity becomes high, and a large amount of heat is required for melting the toner. As a result, the heat roller cannot be downsized, which tends to hinder downsizing of the developing device and power saving. It is in.

(12) 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 if necessary.
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 Is a core made of styrene polymer
Shell-type particles and the like.

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.

[0050]

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 gST; 35 ° C.) The dissolution amount of polyfunctional ester compound in styrene is 3
The amount of the polyfunctional ester compound dissolved in 100 g of styrene kept at 5 ° C. (g / 100 g ST) was measured. (2) Acid value (mgKOH / g) The acid value was measured according to JIS K1557-1970. About 50 g of a sample is weighed correctly in a 300 ml beaker, 128 ml of acetone (80 v / v%) is added thereto, and after dissolution,
This solution is subjected to potentiometric titration with a 0.1 N NaOH aqueous solution using a PH meter, and the inflection point of the obtained titration curve is set as the end point. The acid value is determined from the following equation. A = [6.61 × (BC) × f] / S where A: acid value (KOHmg / g) B: amount of 0.1N aqueous sodium hydroxide solution (ml) required for titration of the sample C: Amount (ml) of 0.1N aqueous sodium hydroxide solution required for titration in blank test f: Factor of 0.1N aqueous sodium hydroxide solution S: Amount of sample (g) N: Standard [1N = (10 ³ mol / cm ³ ) / z] (z
Is the charge number of the ion)

(3) Maximum Endothermic Peak Temperature (° C.) The maximum endothermic peak temperature of the polyfunctional ester compound 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, “SSC5200” manufactured by Seiko Instruments Inc. was used. For the toner, the enthalpy of fusion ΔH (J / g) at the time of measuring the maximum endothermic peak temperature was also measured. (4) Volume average particle size (dv) and particle size distribution (dv / d)
p) Volume average particle diameter (dv) of polymer particles, and ratio (dv / dp) of volume average particle diameter (dv) to number average particle diameter (dp)
The particle size distribution represented by was measured with a Multisizer (manufactured by Coulter Inc.). Multisizer measurement
The measurement was performed under the conditions of an aperture diameter of 100 μm, a medium of Isoton II, a concentration of 10%, and the number of measured particles = 50,000.

(5) Sphericity (dl / ds) A photograph of the toner is taken by a scanning electron microscope, and the photograph is read by an image processing apparatus of a Nexus 9000 type, and the ratio (rl) between the major axis rl and the minor axis rs of the toner is obtained. / Rs) and measured for sphericity. The measured number of toners at this time was 100. (6) 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. (7) Volume resistivity (logΩ · cm) The volume resistivity of the toner was measured using a dielectric loss measuring device (TRS-10 manufactured by Ando Electric Co.) at a temperature of 30 ° C. and a frequency of 1 kHz
It measured under the conditions of z.

(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 black solid, and the fixing roll temperature when the offset occurred was defined as the offset temperature.

(10) Fluidity The three liquids having openings of 150 μm, 75 μm and 45 μm, respectively.
The seed sieves are stacked in this order from the top, and 4 g of the developer to be measured is precisely weighed and placed on the uppermost sieve. Next, the three kinds of the sifted screens were subjected to a vibration intensity scale of 4 using a powder measuring machine (manufactured by Hosokawa Micron Co., Ltd .; trade name: "Powder Tester").
After shaking for 5 seconds, the weight of the developer remaining on each sieve is measured. Substituting each measurement into the following equation:
The values of b and c are determined, and then these values are put into an equation to calculate the value of the fluidity. The measurement was performed three times per sample, and the average value was determined. a = [(weight of developer remaining on 150 μm sieve (g)) / 4
g] × 100 b = [(weight of developer remaining on 75 μm sieve (g)) / 4
g] × 100 × 0.6 c = [(weight of developer remaining on 45 μm sieve (g)) / 4
g] × 100 × 0.2 Fluidity (%) = 100− (a + b + c) (11) Storage (%) After the developer is placed in a sealable container and sealed, the container is cooled to a temperature of 50 ° C. Submerge in the set water bath. After a certain period of time, 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.

(12) Environmental Dependence of Image Quality A commercially available non-magnetic one-component developing system printer (printing speed =
(16 sheets / min), the developer to be evaluated was put into the developing device of this printer, and the temperature was 35 ° C. and the relative humidity was 80% (H /
H) Environment, temperature 10 ° C, relative humidity 20% (L / L)
1 day continuous printing from the beginning after leaving for 24 hours in each environment
After performing 0000 sheets, the image quality is such that the print density is 1.3 or more with a reflection densitometer (manufactured by Macbeth) and the fog of the non-image portion of the photoreceptor is 15% or less as measured by a whiteness meter (manufactured by Nippon Denshoku). The number of continuous prints that can be maintained was examined. Adhesive tape (Scotch Mending Tape 810-3-18 manufactured by Sumitomo 3M) is applied to the non-image area on the photoreceptor and then peeled off, and the whiteness of the adhesive tape applied to the non-image area before printing is A. ,
The whiteness of the adhesive tape attached to the non-image area after printing is represented by B
Then, fog can be calculated by the following equation. Fog (%) = [(AB) / A] × 100 Continuous printing was performed at 5% print density, and print density and fog were 5%.
The inspection was performed every 00 sheets. The results were evaluated according to the following criteria. ◎: No problem in image characteristics even after printing 10000 sheets ○: No problem in image characteristics even when printing from 7500 to 9999 sheets Δ: No problem in image characteristics even when printing from 5000 to 7499 sheets X: A problem occurred in image characteristics with 4999 or less sheets. (13) Durability of image quality Using the above-mentioned printer, continuous printing is performed from the beginning under environmental conditions of normal temperature / normal humidity (N / N; temperature 23 ° C., relative humidity 50%), and a reflection densitometer (Macbeth The number of continuous prints (less than 1000 sheets) that can maintain an image quality of not less than 15% with a print density of 1.3 or more and a non-image portion of the photoreceptor measured by a whiteness meter (manufactured by Nippon Denshoku) of 15% or less Was truncated).

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, hexaglycerin tetrastearate tetrabehenate (number of ester bonds = 8, dissolution amount = 20 g or more, maximum endothermic peak temperature = 63.7 ° C., molecular weight = 2814, acid value = 1. 10 parts (1 mg KOH / g) was added, mixed and dissolved to prepare a monomer composition. All preparations of the monomer composition were performed at room temperature (23 ° C.). (2) Preparation of aqueous dispersion medium At room temperature, 9.5 parts of magnesium chloride (a 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 (alkali metal hydroxide). )
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 colloidal dispersion prepared in the above (2) at room temperature and stirred until the droplets are stabilized. After that, t-butyl peroxyisobutyrate (manufactured by NOF CORPORATION,
5 parts of trade name "Perbutyl IB") were added. Then
Ebara Milder (manufactured by EBARA CORPORATION, trade name "MDN3
Using a “03V type”), high-shear stirring was performed at a rotation speed of 15,000 rpm 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) was charged into a reactor equipped with a stirring blade, and a polymerization reaction was started at 95 ° C. 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 6.4 μm, and volume average particle diameter (dv) / number average particle diameter (dp) was 1.28. The sphericity of the polymer particles was 1.12.

(5) Preparation of Developer Colloidal silica (trade name “RX-200”, manufactured by Nippon Aerosil Co., Ltd.) was added to 100 parts of the polymer particles obtained in the above (4) at room temperature. Was added and mixed using a Henschel mixer to prepare a non-magnetic one-component developer. When the volume resistivity of the toner thus obtained was measured, it was 11.3 (log Ω · cm). (6) Developer Characteristics When the fixing temperature was measured using the developer obtained in the above (5), it was 140 ° C. Further, the preservability and fluidity of this developer were very good. In the image evaluation, the environmental characteristics were up to 10,000 sheets, and the durability was 20,000.
Up to the sheet, an image with high image density, no fog and unevenness, and extremely good resolution was obtained. Table 1 shows the results.

Example 2 In the step of “(1) Preparation of monomer composition” in Example 1, hexaglycerin hexastearate dibe was used instead of hexaglycerin tetrastearate tetrabehenate as the polyfunctional ester compound. Example 1 except that henate (number of ester bonds = 8, dissolution amount = 30 g or more, maximum endothermic peak temperature = 60.8 ° C., molecular weight = 2702, acid value = 1.00 mg KOH / g)
In the same manner as described above, polymer particles and a toner were obtained. The volume average particle diameter (dv) of the obtained polymer particles is 6.5 μm,
Volume average particle diameter (dv) / number average particle diameter (dp) is 1.2
7, and the sphericity was 1.14. In the image evaluation, an image having a high image density, no fog and unevenness, and an extremely good resolution was obtained. Table 1 shows the results.

Example 3 (A) Preparation of Monomer Composition In the step of “(1) Preparation of monomer composition” in Example 1,
As a colorant, a yellow pigment (trade name "toneryello" manufactured by Clariant Co., Ltd.) is used instead of 6 parts of carbon black.
w HG VP2155 ") except that 5 parts were used.
A monomer composition was prepared in the same manner as in Example 1. (B) Preparation of aqueous dispersion medium An aqueous dispersion medium was prepared in the same manner as in “(2) Preparation of aqueous dispersion medium” in Example 1. (C) Granulation step Into the magnesium hydroxide colloidal dispersion prepared in (B), at room temperature, the monomer composition prepared in (A) is charged, and stirred until the droplets are stabilized. T-butyl peroxyisobutyrate (manufactured by NOF Corporation,
5 parts of trade name "Perbutyl IB") were added. Then
Ebara Milder (manufactured by EBARA CORPORATION, trade name "MDN3
Using a “03V type”), high-shear stirring was performed at 15,000 rpm for 30 minutes to granulate fine droplets of the monomer composition.

(D) Synthesis of Core Particles The aqueous dispersion medium (suspension) of the monomer mixture granulated in the above (C) is put into a reactor equipped with a stirring blade, and a polymerization reaction is started at 60 ° C. I let it. When the polymerization conversion reached almost 100%, sampling was performed, and the particle size of the produced polymer particles (core particles) was measured. As a result, the volume average particle size (dv) of the core particles was 6.2 μm, and the volume average particle size (d
v) / number average particle diameter (dp) was 1.23. (E) Preparation of polymerizable monomer for shell Methyl methacrylate (calculated Tg = 105 ° C.) at room temperature
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.

(F) Synthesis of Polymer Particles Having a Core / Shell Structure The polymerizable monomer for shell and 0.2 part of a water-soluble initiator (manufactured by Mitsubishi Gas Chemical Company, ammonium persulfate) were dissolved in distilled water 65
This was placed in the reactor (D), and polymerization was continued for 4 hours in the presence of the core particles. Thereafter, the reaction was stopped to obtain a pH 9.5 aqueous dispersion containing the produced core-shell structure polymer particles. While stirring this aqueous dispersion at room temperature, sulfuric acid was added to adjust the pH of the system to 4 or less, acid washing (25 ° C., 10 minutes) was performed, and water was separated by filtration. Then, 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. After the solid content was separated by filtration, drying was carried out at 45 ° C. for 24 hours in a drier to collect polymer particles having a core-shell structure. The volume average particle size (dv) of the obtained polymer particles is 6.3 μm, the volume average particle size (dv) / number average particle size (dp) is 1.25, and the sphericity is 1.14. there were. The shell thickness calculated from the amount of the polymerizable monomer for the shell and the particle size of the core is 0.02 μm.
Met. (G) Preparation of Developer Colloidal silica (trade name “RX-200”, manufactured by Nippon Aerosil Co., Ltd.) obtained by subjecting 100 parts of the polymer particles having a core-shell structure obtained above to hydrophobic treatment at room temperature.
6 parts were added and mixed using a Henschel mixer to prepare a non-magnetic one-component developer. When the volume resistivity of the toner thus obtained was measured, it was 11.5 log.
Ω · cm. When the fixing temperature was measured using the thus obtained developer, it was 140 ° C. The preservability and fluidity of this developer were very good. In the image evaluation, an image having a high image density, no fog and unevenness, and an extremely good resolution was obtained. Table 1 shows the results.

[Comparative Example 1] In the step of “(1) Preparation of monomer composition” in Example 1, pentaerythritol tetrabe was used as the polyfunctional ester compound in place of 10 parts of hexaglycerin tetrastearate tetrabehenate. Henate (number of ester bonds = 4, dissolution amount = 5 g or less, maximum endothermic peak temperature = 81.0 ° C., molecular weight = 1424, acid value =
(1.0 mgKOH / g) Except for using 3 parts, the same procedure as in Example 1 was carried out. The polymerization system became unstable, the particle size distribution of the polymer particles after drying became wide, and coarse aggregates (scale) were generated. Therefore, the obtained polymer particles were not practical as a toner, but were subjected to various tests. In the durability test, filming occurred.

Comparative Example 2 In the step of “(1) Preparation of monomer composition” in Example 1, triglycerin pentastearate (polyglycerol tetrastearate) was used in place of hexaglycerin tetrastearate tetrabehenate as the polyfunctional ester compound. Number of ester bonds = 5, dissolution amount = 10 g or more, maximum endothermic peak temperature = 56.7 ° C., molecular weight = 1570, acid value = 1.2 mg
KOH / g) was used in the same manner as in Example 1. The solubility of the polyfunctional ester compound in the monomer phase was poor, and heating was required. In the fixing property test, the fixing temperature was high and the hot offset occurrence temperature was low.
Table 1 shows the results.

[0065]

[Table 1]

(Footnotes) (1) HGTSTB: hexaglycerin tetrastearate tetrabehenate (2) HGHSDB: hexaglycerin hexastearate dibehenate (3) PETB: pentaerythritol tetrabehenate (4) TGPS: tri Glycerin pentastearate

According to the present invention, the fixing temperature is low, energy can be saved, printing and copying can be performed at a high speed, and color printing can be performed. An electrostatic image developing toner capable of forming image quality is provided.

Claims (3)

[Claims] 1. An electrostatic image developing toner containing at least a binder resin, a colorant and a polyfunctional ester compound, wherein the polyfunctional ester compound has five or more ester bonds in the molecule (a). (B) the molecular weight is 2,000 or more,
(c) A toner for developing an electrostatic charge image, characterized in that the amount dissolved in 100 g of styrene measured at 35 ° C. is 5 g or more, and (d) the acid value is 2 mgKOH / g or less. 2. In a DSC curve measured by a differential scanning calorimeter, the polyfunctional ester compound is 50% at elevated temperature.
2. The electrostatic image developing toner according to claim 1, wherein the toner has a maximum endothermic peak in a range of from about 80 [deg.] C. 3. The toner having a maximum endothermic peak in the range of 50 to 80 ° C. at the time of temperature rise in a DSC curve measured by a differential scanning calorimeter, and having a melting enthalpy ΔH of 1 to 50 J / g at that time. The toner for developing an electrostatic image according to claim 1, wherein