JPH07152202A - Electrostatic charge developing toner, its production and developer - Google Patents

Abstract

PURPOSE:To obtain such a toner capable of being made into small particle size, excellent in reproducibility of color tone, electrification property, and environmental resistance and causes no deterioration in image qualities nor cleaning defect even when repeatedly used, by dissolving or dispersing a material containing a polyester resin and a coloring agent in a solvent, then granulating the obtd. liquid in a water medium containing inorg. dispersant and removing the solvent. CONSTITUTION:A polyester resin is used as a binder resin for the toner, and a coloring agent and other additives as required are added to the toner. These polyester resin, coloring agent and other additives are dissolved or dispersed in a solvent capable of dissolving the polyester resin. Then, the prepared liquid (toner base liquid) containing the polyester resin, coloring agent and other additives dissolved or dispersed in the solvent is granulated into a specified particle size in a water medium containing an inorg. dispersant. As for the water medium, water is generally used. Thus, the toner base liquid is granulated in the water medium and the solvent is removed. After the solvent is removed, the obtd. toner is preferably washed with hydrochloric acid or the like.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner for developing an electrostatic charge image which visualizes an electrostatic charge image formed on the surface of a photoreceptor in electrophotography, electrostatic recording and the like, a method for producing the same and a toner for using the toner. Related to the developer.

[0002]

2. Description of the Related Art An electrophotographic system is disclosed in US Pat.
No. 7,691, British Patent Nos. 1,165,406 and 1,165,405, a photoconductive material is uniformly applied to a photoreceptor. A charging step for imparting an electrostatic charge, an exposure step for irradiating light to form an electrostatic latent image, a developing step for adhering toner to a latent image portion, a transfer step for transferring to a toner image support, a heat treatment for the toner image, It consists of a fixing process to fix it to the image support with pressure, flash light, etc., a cleaning process to remove the toner remaining on the photoconductor, and a static elimination process to remove the electrostatic charge on the photoconductor and return it to the initial state. Repeatedly produces several prints.

As an electrostatic charge image developing toner used in the field of electrophotography, a toner using a polyester resin obtained by subjecting a glycol having a bisphenol skeleton and a polybasic acid to a condensation reaction (Japanese Patent Publication No. 25-25420). Gazette), toner using polystyrene resin (Japanese Patent Publication No.
16118), a toner using a styrene / butyl methacrylate copolymer resin (Japanese Patent Publication No. 56-11143), and a toner using a bisphenol type epoxy resin obtained by reacting bisphenol with epichlorohydrin (JP-A-57- No. 96354) is known.

[0004]

By the way, in recent years, with the diversification of information, as for the method of expressing information, instead of the conventional image formation with monochrome toner, image formation with color toner is required. Came. In many cases, a toner using a polyester resin having excellent color tone reproducibility is used for such color processing. Further, there is a demand for a toner having a high resolution, that is, a toner having a small particle size capable of fine expression in response to the movement of higher density of information. However, in response to such market trends, conventional so-called pulverization toner, in which a polyester resin, a colorant, and other additives are melt-kneaded and then pulverized, has various problems described below.

(1) In order to obtain a toner having excellent color tone reproducibility, a low molecular weight polyester resin that sharply melts at the time of fixing is necessary. However, since it has a low molecular weight, a colorant and other additives are added during melt kneading. The color tone of the fixed image is poor due to insufficient dispersion, and the image quality is poor due to the inhomogeneous toner composition. (2) Since it is a low molecular weight polyester resin, the melt-kneaded product is easily over-milled and the yield is low. Further, finely pulverized particles scatter during printing to deteriorate image quality or pollute the environment. The present invention solves the above problems, is excellent in color tone reproducibility, can be reduced in particle size, is excellent in charging property and environment resistance,
The present invention provides a toner that does not cause deterioration of image quality and cleaning failure even after repeated use, a method for producing the toner, and a developer using the toner.

[0006]

According to the present invention, a liquid obtained by dissolving or dispersing a material containing a polyester resin and a colorant in a solvent in which the polyester resin can be dissolved in an aqueous medium containing an inorganic dispersant. The present invention relates to a toner for developing an electrostatic charge image obtained by removing the solvent after granulation in (1) and a developer containing the toner and a carrier. Further, the present invention is to dissolve or disperse a polyester resin, a colorant and an additive in a solvent in which the polyester resin can be dissolved, and then to predetermined this in an aqueous medium containing an inorganic dispersant under high-speed shearing. The present invention relates to a method for producing an electrostatic charge image developing toner, which comprises granulating to a particle size and then removing the solvent.

A polyester resin is used as the binder resin of the toner for developing an electrostatic image according to the present invention. The following may be mentioned as raw materials for the polyester resin. As the alcohol component, polyoxypropylene (2,2) -2,2-bis (4-hydroxyphenyl)
Propane, polyoxypropylene (3,3) -2,2-
Bis (4-hydroxyphenyl) propane, polyoxyethylene (2,0) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (2,0)-
General formula (I) such as polyoxyethylene (2,0) -2,2-bis (4-hydroxyphenyl) propane

[Chemical 1] (Wherein, R ¹ and R ² are ethylene groups or propylene groups, x and y are each an integer of 1 or more, and the average value of the sum thereof is 2 to 7), Ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, isopentyl glycol, hydrogenated bisphenol A, 1,3-butanediol,
1,4-butanediol, neopentyl glycol, xylylene glycol, 1,4-cyclohexanedimethanol, glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, bis- (β-hydroxyethyl) terephthalate, tris- (β -Hydroxyethyl) isocyanurate, 2,2,4-trimethylolpentane-1,3-diol and the like, and a hydroxycarboxylic acid component can be further added. For example, p-oxybenzoic acid, vanillic acid, dimethylolpropionic acid, malic acid, tartaric acid, 5-hydroxyisophthalic acid and the like. Specific examples of the acid component include malonic acid, succinic acid, glutaric acid, dimer acid, phthalic acid, isophthalic acid, terephthalic acid, dimethyl isophthalate,
Terephthalic acid dimethyl ester, terephthalic acid monomethyl ester, tetrahydrophthalic acid, methyltetrahydrophthalic acid, hexahydrophthalic acid, dimethyltetrahydrophthalic acid, endomethylenehexahydrophthalic acid,
Naphthalenetetracarbonic acid, diphenolic acid, trimellitic acid, pyromellitic acid, trimesic acid, cyclopentanedicarboxylic acid, 3,3 ', 4,4'-benzophenonetetracarboxylic acid, 1,2,3,4-butane Tetracarboxylic acid, 2,2-bis- (4-carboxyphenyl)
Diimidecarboxylic acid obtained from propane, trimellitic anhydride and 4,4-diaminophenylmethane, tris- (β-carboxyethyl) isocyanurate, isocyanurate ring-containing polyimidecarboxylic acid, tolylene diisocyanate, xylylene diisocyanate or isophorone Isocyanate ring-containing polyimidecarboxylic acid obtained from a trimerization reaction product of diisocyanate and trimellitic anhydride, and one or more of these are used. Of these, the use of a crosslinking component such as a trivalent or higher polycarboxylic acid or polyhydric alcohol may be preferable in terms of stability such as fixing strength and offset resistance.

The polyester resin obtained from these raw materials is manufactured by a usual method. For example, an acid component and an alcohol component are charged into a reaction vessel at a predetermined ratio, and the reaction is started at a temperature of 150 to 190 ° C. in the presence of an inert gas such as nitrogen gas. By-produced low molecular weight compounds are continuously removed from the reaction system. After that, the reaction temperature is further increased to 200 to 2
The temperature is raised to 50 ° C. to accelerate the reaction and obtain the target polyester resin. When producing a polyester resin, when the carboxylic acid component used is a free carboxylic acid that does not contain an ester group, it is represented by an esterification catalyst, for example, an organic metal such as dibutyltin dilaurate or dibutyltin oxide, or tetrabutyl titanate. It is preferable to use 0.1 to 1% by weight based on the total amount of raw materials charged, such as metal alkoxides. When the carboxylic acid component is a lower alkyl ester, a transesterification catalyst such as zinc acetate, lead acetate or magnesium acetate is used. Metal acetate and zinc oxide,
It is preferable to use a metal oxide such as antimony oxide or a metal alkoxide such as tetrabutyl titanate in an amount of 0.005 to 0.05% by weight based on the total amount of the raw materials charged.

The glass transition temperature of the polyester resin as the binder resin is preferably 35 to 100 ° C.,
It is particularly preferable to adjust the temperature to ˜90 ° C. When the glass transition temperature is lower than 35 ° C., the toner is apt to cause blocking (a phenomenon in which toner particles aggregate and agglomerate) during storage or in a developing machine. On the other hand, when the glass transition temperature exceeds 100 ° C., a large amount of heat energy is required for fixing the toner.
In the toner of the present invention, the above polyester resin is used
One or more species may be used in combination, or another resin may be added and used. Other resins include silicone resin, epoxy resin, xylene resin, diene resin, styrene resin, acrylic resin, styrene / acrylic resin, phenol resin, terpene resin, coumarin resin, amide resin, amide imide resin, butyral resin, urethane resin. , Ethylene / vinyl acetate resin, etc. In the present invention, it is preferable to use a polyester resin as a main component and other resins in the toner in an amount of 0 to 30% by weight. The binder resin is preferably blended in the toner in an amount of 60 to 95% by weight. If this amount is less than 60% by weight, the binding force to the toner image support is weak and the toner image is likely to be lost when the toner image support is bent or rubbed, and information is likely to be lost. On the other hand, if it exceeds 95% by weight, the toner image hiding power tends to be insufficient, and poor print quality tends to occur.

The toner of the present invention contains a colorant and, if necessary, other additives. Carbon black, acetylene black, iron black, as colorant for black toner,
Aniline black, cyanine black, etc.
Carbon black is preferably used. Naphthol Yellow S as a yellow colorant for color toner
(C.I. 10316), Hansa Yellow 10G (C.I.
I. 11710), Hansa Yellow 5G (C.I. 116)
60), Hansa Yellow G (C.I. 11680), Hansa Yellow R (C.I. 12710), Pigment Yellow L (C.I. 12720), Benzidine Yellow G (C.I.
I. 21095), permanent yellow NCG (C.
I. 20040), Vulcan First Yellow 5G
(C.I. 21220), quinoline yellow (C.I. 4)
7005), Permanent Yellow FGL (C.I. 11)
767), permanent yellow HR (C.I. 2110)
8) and the like.

Permanent Red 4 as a red colorant
R (C.I. 12070), Para Red (C.I. 12)
120), Brilliant Fast Scarlet (C.
I. 12315), Brilliant Carmine BS (C.
I. 12351), Permanent Red F4R (C.
I. 12335), Vulcan Fast Rubin B (C.
I. 12320), Light Fast Red Toner B
(C.I. 12450), Lake Red C (C.I. 1
5585: 1), Brilliant Carmine 6B (C.I.
15850: 1), Rhodamine Rake B (C.I. 45)
170: 2) and the like.

Cobalt blue (C.I.
I. 77346), alkali blue lake (C.I. 4)
2750: 1), Victoria Blue Rake (C.I.4)
4045: 2), metal-free phthalocyanine blue (C.
I. 74100), phthalocyanine blue (C.I.
4160), Fast Sky Blue (C.I. 741)
80: 1) and the like. Further, as orange colorants, permanent orange (C.I. 12075), vulcan first orange GG (C.I. 2116)
5), Indanthrene Brilliant Orange RG (C.
I. 59300), fast violet B (CI. 12321) as a purple colorant, methyl violet lake (CI. 42535), pigment green B (CI. 10006) as a green colorant, acid green lake, Phthalocyanine green (C.I.
74260) and other organic pigments, inorganic pigments and dyes. The above colorants can be used alone or as a mixture. These colorants are 0.1 to 15% by weight in the toner.
It is preferably added.

Various other additives may be mentioned. For example, in order to obtain a toner for developing an electrostatic image having magnetism, a magnetic or magnetizable material such as hematite and magnetite containing oxides of iron, cobalt and nickel can be added. Further, as an anti-offset agent, lower alcohol esters of fatty acids such as butyl stearate and propyl stearate, higher alcohol esters of fatty acids such as casta wax and diamond wax, palm aceti, Hoechst wax E, hexti wax OP, carnauba wax, etc. Higher Alcohol Ester, Bisamide Blast Flow, Amide 6L, 7
S, 6H, alkylenebis fatty acid amide compounds such as Hoechst wax C, ethylene, propylene, butene, hexene, heptene, octene, nonene, decene, 3-methyl-1-butene, 3-methyl-2-pentene, 3-propyl Polymers of olefin monomers such as -5-methyl-2-hexene or the above olefin monomers and acrylic acid,
Examples thereof include copolymers with methacrylic acid, butyl acetate and the like. Of these, polypropylene is particularly preferable.
These are preferably added in an amount of 0.1 to 10% by weight or less, particularly 0.1 to 5% by weight, based on the toner. 0.1% by weight
If the amount is less than the above range, it is difficult to sufficiently exert the offset preventing effect, and if the amount exceeds 10% by weight, the powder fluidity of the toner is lowered and the developability is deteriorated, or the transparency of the toner is lowered to obtain a desired color tone. It gets harder.

Further, a positive charge or negative charge control agent may be used as long as it does not impair the color tone of the fixed toner image. As the positively chargeable charge control agent, for example, bontron 0 which is a nigrosine dye of an azine compound
3, Quaternary ammonium salt Bontron P-51 (above, trade name manufactured by Orient Chemical Industry Co., Ltd.), quaternary ammonium salt molybdenum complex TP-302 (trade name manufactured by Hodogaya Chemical Industry Co., Ltd.), TP- 415 (trade name of Hodogaya Chemical Co., Ltd.), quaternary ammonium salt copy charge (Copy Charge) PSY VP2038, triphenylmethane derivative copy blue (Copy Blue)
PR (above, trade name of Hoechst), L
RA-901 (trade name of Nippon Carlit Co., Ltd.) and the like can be mentioned. As the negatively chargeable charge control agent, a metal-containing azo dye, Bontron S-34, an oxynaphthoic acid-based metal complex E-82, a salicylic acid-based metal complex E-84, a phenol-based condensate E-89 (above, Orient Chemical Industry Co., Ltd. product name), copy of quaternary ammonium salt
Examples of the charge include Copy Charge NEG VP2036, Copy Charge NX VP434 (above, trade name manufactured by Hoechst Co., Ltd.), and a boron complex LR-147 (trade name manufactured by Japan Carlit Co., Ltd.). These charge control agents may be used alone or as a mixture, and may be used in the toner.
It is preferable to add 0% by weight or less, particularly 0.5 to 3% by weight. If the addition amount exceeds 5% by weight, the charge amount is high and the printing density is low from the initial stage, the transferability from the photoconductor to the toner support is poor, and the cleaning property of the transfer residual toner adhering to the photoconductor is poor. There is a tendency for problems such as inferiority to occur.

Further, known silica powder may be added.
As such silica powder, Aerosil R97
2, R974, Silica D-17, T-80
5, R-812, RA200, HRX-C (all manufactured by Nippon Aerosil Co., Ltd.), Taranox 500 (manufactured by Tarco), Cab-o-Sil M-5, MS-7, MS.
-75, HS-5, EH-5, S-17, TS-72
(Above, manufactured by Cabot). When these are used, it is preferable that the content thereof in the toner be 3% by weight or less.

In the present invention, these polyester resin, colorant and other additives used as required are dissolved or dispersed in a solvent in which the polyester resin can be dissolved. Whether or not a polyester resin can be dissolved depends on the constituent components of the polyester resin, the molecular chain length, the degree of three-dimensionalization, etc., so it cannot be said unequivocally, but generally hydrocarbons such as toluene, xylene, and hexane are included. , Halogenated hydrocarbons such as methylene chloride, chloroform, dichloroethane, dichloroethylene, alcohols or ethers such as ethanol, butanol, benzyl alcohol ethyl ether, benzyl alcohol isopropyl ether, tetrahydrofuran, tetrahydropyran, methyl acetate, ethyl acetate, butyl acetate, acetic acid Esters such as isopropyl, acetone, methyl ethyl ketone, diisobutyl ketone, dimethyl oxide, diacetone alcohol, ketones such as cyclohexanone and methylcyclohexanone, or acetals are used. That.

These solvents dissolve the polyester resin, and it is not necessary to dissolve the colorant and other additives. The colorant and other additives may be dispersed in the polyester resin solution. The amount of solvent used is not limited, but may be any viscosity as long as it can be granulated in an aqueous medium. The ratio of the material containing the polyester resin, the colorant and other additives (the former) and the solvent (the latter) is 10/90 to 50 /
50 (former / latter weight ratio) is preferable in terms of easiness of granulation and final toner yield.

Liquid of polyester resin, colorant and other additives dissolved or dispersed in a solvent (toner mother liquor)
Is granulated to have a predetermined particle size in an aqueous medium containing an inorganic dispersant. Water is mainly used as the aqueous medium. The mixing ratio of the aqueous medium and the toner mother liquor is as follows: aqueous medium / mother liquor = 90/10
50/50 (weight ratio) is preferable. The inorganic dispersant is preferably selected from tricalcium phosphate, hydroxyapatite, calcium carbonate, titanium oxide and silica powder. Particularly preferred are tricalcium phosphate and hydroxyapatite. The reason for this is that there is very little adverse effect on the granulation property and its stability, and further on the properties of the obtained toner. The amount of the inorganic dispersant used is determined according to the particle size of the particles to be granulated, but generally it is preferably used in the range of 0.1 to 15% by weight based on the toner mother liquor. If it is less than 0.1% by weight, it is difficult to perform good granulation, and if it is used in excess of 15% by weight, unnecessary fine particles are generated and it is difficult to obtain target particles in high yield.

In order to satisfactorily granulate the toner mother liquor in an aqueous medium containing an inorganic dispersant, an auxiliary agent may be added to the aqueous medium. Examples of such an auxiliary include known cation-type, anion-type and nonion-type surfactants, and anion-type surfactants are particularly preferable. For example, there are sodium alkylbenzene sulfonate, sodium α-olefin sulfonate, sodium alkyl sulfonate, etc., which are 1 × 10 ⁻⁴ to the toner mother liquor.
It is preferably used in the range of 0.1% by weight.

Granulation of the toner mother liquor in an aqueous medium containing an inorganic dispersant is preferably carried out under high speed shear. The toner mother liquor dispersed in the aqueous medium is preferably granulated to have an average particle size of 10 μm or less. Particularly, 4 to 9 μm is preferable. The particle size of the dispersion-granulated toner mother liquor is too large,
That is, if the particle size of the obtained toner is too large, it becomes difficult to achieve high resolution, or when the three primary colors in the case of a full-color toner are mixed to express an intermediate color, the melting and mixing properties become insufficient and the intermediate color becomes difficult to appear. To do. There are various types of high-speed dispersers as a device equipped with a high-speed shearing mechanism, and among them, a homogenizer is preferable. The homogenizer allows substances that are incompatible with each other (in the present invention, an aqueous medium containing an inorganic dispersant and a toner mother liquor) to pass through a narrow gap between the casing and a rotor that rotates at high speed, so that a certain liquid is made compatible with the liquid. This is a device for dispersing insoluble substances into fine particles. As such homogenizer, TK homomixer, line flow homomixer (above, manufactured by Tokushu Kika Kogyo Co., Ltd.), Silverson homogenizer (manufactured by Silverson Co., Ltd.), Polytron homogenizer (KINEMATICA (KINEMA)
TICA) made by AG).

The stirring conditions using the homogenizer are preferably at least 2 m / sec at the peripheral speed of the rotor blades. If it is less than this range, atomization tends to be insufficient. In the present invention, the toner mother liquor is granulated in an aqueous medium containing an inorganic dispersant, and then the solvent is removed. The solvent may be removed at room temperature and atmospheric pressure, but it takes a long time to remove it, and therefore it is preferable to perform it under a temperature condition that is lower than the boiling point of the solvent and has a difference from the boiling point of 80 ° C. or less. The pressure may be atmospheric pressure or reduced pressure,
The pressure is preferably reduced to 20 to 150 mmHg.

After removing the solvent, the toner of the present invention is preferably washed with hydrochloric acid or the like. As a result, the inorganic dispersant remaining on the toner surface can be removed, and the composition of the toner can be changed to the original composition to improve the characteristics. Then, dehydration and drying are performed to obtain powdery toner particles. In order to further improve physical properties such as fluidity and chargeability, the toner for developing an electrostatic image of the present invention has the above-mentioned silica fine powder, vinyl (co) polymer, and zinc stearate on the surface of toner particles. Further, fine particles of aluminum oxide, titanium oxide or the like can be further added and mixed as a toner external additive. When these are added, they are preferably mixed in an amount of 0.05 to 5% by weight with respect to the toner before addition. The toner thus obtained can be mixed with a carrier to form a developer. The type of carrier is not particularly limited, and iron oxide powder, various ferrites,
Well-known materials such as magnetite can be used. The mixing ratio of the toner and the carrier is not particularly limited, and a known mixing ratio can be used. Generally, 1 to 10% by weight of toner is used in the developer. The electrostatic charge image developing toner and developer of the present invention can be used in various known developing means and fixing means.

[0023]

EXAMPLES The present invention will be described in detail below with reference to examples. Examples and Comparative Examples (1) Production of Polyester Resin The acid component and alcohol component shown in Table 1 were charged into a reaction vessel, and the temperature was gradually raised while blowing nitrogen gas to 18
After advancing the condensation reaction at 0 ° C for 5 hours, the reaction was completed at 230 ° C. The glass transition temperatures of the resins obtained are also shown in the table.

[0024]

[Table 1]

(2) Production of Toner A toner mother liquor was produced by dispersing the colorant (pigment), polyester resin, solvent and other additives shown in Table 2 in a ball mill until the pigment particles became submicron. This toner mother liquor was granulated in a dispersion medium containing the inorganic dispersant shown in Table 2 by using a homogenizer so that the average particle size was in the range of 5 to 9 μm. The peripheral speed of the rotor is 6-8m /
Adjusted in the range of seconds. Then, the temperature is lower than the boiling point of the solvent, and the difference from the boiling point is 80 ° C. or less under normal pressure to
The solvent was distilled off under reduced pressure. When toluene is used as the solvent, the temperature is 50 to 70 ° C., the reduced pressure is 30 to 150 mmHg,
When methylene chloride is used, the temperature is 20 to 30 ° C. under normal pressure, and when methyl ethyl ketone is used, the temperature is 50 to 30 ° C.
It was removed at 70 ° C. under a reduced pressure of 30 to 150 mmHg. After cooling
12N Hydrochloric acid was added until the pH reached 2, the inorganic dispersant was washed off, washed with water, dried and classified to obtain a solid toner having an average particle diameter in the range of 4 to 8 μm. Next, toner 100
The toner external additives shown in Table 2 were added to parts by weight, and the mixture was stirred and mixed with a Henschel mixer. The 5 wt% aqueous solution of hydroxyapatite was obtained by reacting trisodium phosphate, calcium chloride and sodium hydroxide aqueous solution in an equivalent to 20% equivalent excess amount.

(3) Evaluation Copper-zinc ferrite carrier 95 coated with 5% by weight of toner and a methyl methacrylate resin and having an average particle size of 60 μm
The developer consisting of weight% is transferred to the copying machine recopy (RICOP
Y) 3 using FT-7570 (manufactured by Ricoh Co., Ltd.)
Continuous printing was performed in an environment of 5 ° C. and a relative humidity of 70%, and the following criteria were evaluated. (A) Reproducibility of color tone: Printing was performed on Mylar paper, the reproducibility of a color image was examined with an OHP (overhead projector), and evaluated according to the following criteria. Good: A chromatic color is expressed and an intermediate color is also expressed. Poor ... Chromatic color does not appear. (B) Image density, fog and resolution Image density and fog were measured using a Macbeth reflection densitometer RD514 type (manufactured by A division kollmorgen Corp.). It was visually determined whether or not the resolution was reached. (C) Toner scattering The presence or absence of toner scattering was visually determined. (D) Cleaning Property The transfer residual toner on the photoconductor that passed through the cleaning process was transferred to a blank sheet of paper with Scotch tape (manufactured by Sumitomo 3M Ltd.), and measured with a Macbeth reflection densitometer RD514 type and compared with a blank.

[0027]

[Table 2]

[0028]

[Table 3]

Example 7 The toners and developers of Examples 1, 2 and 3 in Table 2 were prepared by using the Konica Digital Full Color 9028 type copying machine (manufactured by Konica Corporation).
After adjusting the initial image and printing, the intermediate color was accurately reproduced and the image quality was good. Comparative Example 1 The binder resin, pigment and charge control agent of Example 1 were premixed with a Henschel mixer and then melt-kneaded with a biaxial kneader. Then, the cooled kneaded product was obtained with a pin mill and a jet mill to obtain an irregular toner having an average particle size of 8 μm, and 0.2% by weight of Aerosil R972 (manufactured by Nippon Aerosil Co., Ltd.) was mixed with a Henschel mixer and evaluated in the same manner. As a result, in the initial stage, the color reproducibility was poor, the image density was 1.2, the fog was 0.1, the resolution was 6.3, the toner was not scattered, and the cleaning property was 0.
(Good), but color tone reproducibility after printing 50,000 pages
Poor, image density 0.8, fog 0.15, resolution 4.0,
The toner was scattered and the cleaning property was 0 (good). Further, the yield of the toner was as low as 60% by weight with respect to the yield of the toner of the present invention of 80 to 90% by weight.

Comparative Example 2 The aqueous medium containing the inorganic dispersant of Example 1 was changed to an aqueous solution in which a 3% by weight aqueous solution of polyvinyl alcohol (Denka Poval W-24 (manufactured by Denki Kagaku Kogyo KK)) was dissolved. Except that a true spherical toner having an average particle size of 6 μm was obtained in the same manner and the performance was evaluated. As a result, the color reproducibility was poor (light is not transmitted) in the initial stage, the image density was 1.2, the fog was 0.1, and the resolution was 0.1. 6.3, toner scattering, cleanability 0
(Good) and not stable to the environment. Poor color reproduction after printing 5,000 pages (no light transmission), image density 0.8, fog 0.2, resolution 4.0, toner scattering
Yes, cleanability was 5 (poor). The yield of the toner was 20% by weight, which was extremely low compared to the yield of the toner of the present invention of 80 to 90% by weight.

[0031]

As is apparent from the above, the toner and developer for developing an electrostatic charge image of the present invention can maintain excellent image quality for a long period of time, and the toner production method of the present invention can be used. For example, the above excellent toner can be obtained in high yield.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Chiaki Okada 4-13-1, Higashimachi, Hitachi, Ibaraki Prefecture Hitachi Chemical Co., Ltd. Yamazaki Plant

Claims (4)

[Claims] 1. A liquid obtained by dissolving or dispersing a material containing a polyester resin and a colorant in a solvent in which the polyester resin can be dissolved is granulated in an aqueous medium containing an inorganic dispersant, and then the solvent. Toner for developing an electrostatic image obtained by removing. 2. The toner for developing an electrostatic charge image according to claim 1, wherein the inorganic dispersant is selected from tricalcium phosphate, hydroxyapatite, calcium carbonate, titanium oxide and silica powder. 3. A material containing a polyester resin and a colorant is dissolved or dispersed in a solvent in which the polyester resin can be dissolved, and then this is subjected to high-speed shearing in an aqueous medium containing an inorganic dispersant to give predetermined particles. A method for producing a toner for developing an electrostatic charge image, which comprises granulating to a diameter, and then removing the solvent. 4. A developer comprising the toner according to claim 1 and a carrier.