JPH07168395A - Negatively chargeable toner for electrostatic charge image development, its production and developer using the same - Google Patents

Abstract

PURPOSE:To provide the production of the toner, with which reduction in particle size of the toner can be attained and the negatively chargeable toner excellent in color tone reproducibility, chargeability and environmental resistance can be produced by granulating a solution contg. as a constituent of the toner material a polyester resin dissolved into a solvent in an aqueous medium contg. an inorganic dispersant that has specified average particle size and removing the solvent from the granules. CONSTITUTION:In this production, the toner material contg. a polyester resin and a colorant is dissolved into a solvent in which the polyester resin is soluble and this toner material solution (toner mother liquor) contg. the dissolved polyester resin and the colorant is granulated into granules having prescribed particle size in an aqueous medium contg. an inorganic dispersant that has 0. 7 to 5mum average particle size. At this time, the mixing ratio of the aqueous medium to the toner mother liquor is preferably 90:10 to 50:50 ((aqueous medium):(toner mother liquor)) by weight. As the inorganic dispersant having 0.7 to 5mum average particle size, calcium tertiary phosphate and/or hydroxyapatite are preferred. After the granulation the solvent is removed from the granules under prescribed conditions of pressure and temp.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a negatively chargeable toner for developing an electrostatic charge image for developing 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 method for producing the same. The present invention relates to a developer using toner.

[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 a negatively charged toner for developing an electrostatic charge image used in the field of electrophotography, a toner using a polyester resin obtained by subjecting a glycol having a bisphenol skeleton to a polybasic acid to undergo a condensation reaction (Japanese Patent Publication No. 52-52). -2542
No. 0), a toner using a polystyrene resin (JP-B-44-16118), and a toner using a styrene-butyl methacrylate copolymer resin (JP-B-56-1114).
3), a toner using a bisphenol type epoxy resin obtained by reacting bisphenol with epichlorohydrin (JP-A-57-96354), and the like.

[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.

As another manufacturing method other than the pulverization method, after dissolving the toner material in a solvent, the solution is treated with an organic dispersant,
For example, it is known to granulate to a predetermined particle size in an aqueous medium containing methylcellulose and then remove the solvent (Japanese Patent Laid-Open No. 1-257856). However, the toner obtained by this method also has many problems. An organic dispersant having a high affinity for water remains on the surface of the toner particles from which the solvent has been removed, resulting in poor charging properties and environmental stability, which are basic characteristics that the toner must have, and are far from practical use. Furthermore, since the residual organic dispersant covers the toner surface to form a thin layer, the toner meltability at the time of fixing is reduced and the original color tone is not expressed, or when used as a full-color toner, the transparency of the fixed toner is reduced. Inferior, the toning property due to mixing of the three primary colors may not remain. Further, since the toner particles have a spherical shape, the untransferred toner on the photoconductor after transferring the toner to the image support is poorly cleaned and cannot be used repeatedly. Further, in order to speed up information processing and improve color image quality, a negatively charged toner is often used in a high speed printing copying machine, a printer or a digital color machine. However, it has been the actual situation that no conventional negatively chargeable toner has sufficient characteristics. The present invention solves the above problems, is excellent in color tone reproducibility, can reduce particle size, is excellent in chargeability and environmental resistance, and causes deterioration of image quality and cleaning failure even after repeated use. The present invention provides a negatively charged toner, a method for producing the same, and a developer using the same.

[0007]

According to the present invention, a toner material containing a polyester resin and a colorant is dissolved or dispersed in a solvent in which the polyester resin can be dissolved, and a liquid having an average particle diameter of 0.7 to The present invention relates to a negatively charged toner for developing an electrostatic charge image obtained by granulating in an aqueous medium containing an inorganic dispersant of 5 μm and then removing the solvent, and a developer containing the toner and a carrier. Further, in the present invention, a toner 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 an inorganic dispersant having an average particle size of 0.7 to 5 μm is prepared. The present invention relates to a method for producing a negatively chargeable toner for developing an electrostatic charge image, which comprises granulating into a predetermined particle size under high-speed shearing in an aqueous medium containing the solvent, and then removing the solvent.

A polyester resin is used as a binder resin for the negatively chargeable toner for electrostatic image development 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 (2,2
General formula (I) such as 0) -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, isophthalic acid dimethyl ester, 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'-benzophenone tetracarboxylic acid, 1,2,3,4-butane tetracarboxylic acid, 2,2-bis- (4-carboxyphenyl) propane, trimellitic anhydride and 4,4- Obtained from diaminophenylmethane Diimidocarboxylic acid, tris-
(Β-carboxyethyl) isocyanurate, isocyanurate ring-containing polyimide carboxylic acid, tolylene diisocyanate, xylylene diisocyanate or isophorone diisocyanate trimerization reaction product and isocyanate ring-containing polyimide carboxylic acid obtained from trimellitic anhydride , 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. 0.1 to 1% by weight based on the total amount of all toner materials charged, such as metal alkoxide
When the carboxylic acid component is a lower alkyl ester, it is preferable to use a transesterification catalyst, for example, a metal acetate such as zinc acetate, lead acetate, magnesium acetate, zinc oxide, a metal oxide such as antimony oxide, or tetrabutyl. It is preferable to use a metal alkoxide such as 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., and 50
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, coumarone 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.

As the other additive which is a toner material, various additives can be mentioned. For example, magnetic or magnetizable toner materials such as hematite and magnetite containing iron, cobalt, and nickel oxides can be added to obtain a magnetic negatively charged toner for developing an electrostatic image. 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, Hoechst wax OP, carnauba wax, etc. Alcohol bis fatty acid amide compounds such as higher alcohol ester, bisamide blast flow, amide 6L, 7S, 6H, Hoechst wax C, ethylene, propylene, butene, hexene, heptene, octene, nonene, decene, 3-methyl-1-butene , 3-
Methyl-2-pentene, 3-propyl-5-methyl-2
Examples thereof include polymers of olefin monomers such as hexene and copolymers of the above olefin monomers with acrylic acid, 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, more preferably 0.1 to 5% by weight, based on the toner. If the amount is less than 0.1% by weight, a sufficient offset preventing effect is difficult to be exhibited, 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. It becomes difficult to obtain the color tone of.

A negatively chargeable charge control agent is preferably used in the negatively chargeable toner of the present invention. 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), quaternary ammonium salt copy charge NEG VP2036,
Examples include Copy Charge NXVP434 (above, trade name manufactured by Hoechst Co., Ltd.), LR-147 which is a boron complex (trade name manufactured by Nippon Carlit Co., Ltd.), and the like. Further, a positively chargeable charge control agent can be used in combination to the extent that good negative chargeability is not impaired. As the positively chargeable charge control agent, for example, bontron B which is a nigrosine dye of an azine compound
Y, Quaternary ammonium salt Bontron P-51 (above, trade name of Orient Chemical Industry Co., Ltd.), quaternary ammonium salt molybdenum complex TP-302, TP-41
5 (above trade name of Hodogaya Chemical Co., Ltd.), quaternary ammonium salt copy charge PSY VP2038,
Examples include copy blue PR (a product name by Hoechst Co., Ltd.) and LRA-901 (a product name by Nippon Carlit Co., Ltd.) of a triphenylmethane derivative. 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 added 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. When a positive charge control agent is used in combination, it is preferable to use 2% by weight or less of the total charge control agent.

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 using these, it is preferable that the content of the toner is 3% by weight or less.

In the present invention, the toner material containing the polyester resin, the colorant and other additives used as required is 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 and dichloroethylene, alcohols and ethers such as ethanol, butanol, benzyl alcohol ethyl ether, benzyl alcohol isopropyl ether, tetrahydrofuran and 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, and acetal are used.

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 toner material (former) containing the polyester resin, the colorant, and other additives optionally used to the solvent (latter) is 10/90 to 50/50 (former / latter weight ratio). It is preferable in terms of easiness of granulation and final toner yield.

A liquid (toner mother liquor) of a toner material containing a polyester resin dissolved or dispersed in a solvent, a colorant, and other additives optionally used is an inorganic dispersion having an average particle diameter of 0.7 to 5 μm. Granulation is performed in an aqueous medium containing the agent so as to have a predetermined particle size. When the average particle size of the inorganic dispersant is less than 0.7 μm or more than 5 μm, a toner having a target particle size cannot be obtained and image characteristics are deteriorated. Water is mainly used as the aqueous medium. The mixing ratio of the aqueous medium and the toner mother liquor is preferably aqueous medium / mother liquor = 90/10 to 50/50 (weight ratio). As the inorganic dispersant having an average particle size of 0.7 to 5 μm, tricalcium phosphate and / or hydroxyapatite is preferable. 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 average particle size referred to here is the submicron particle analyzer Coulter (SUB-MICRON
PARTICLE ANALYZER COURTER model N4MD (manufactured by COURTER ELECTRONICS) is a value measured in a state of being dispersed in an ethanol solution. Dispersion in an ethanol solution was performed by ultrasonic treatment for 3 to 5 minutes.

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 granulate well,
When 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. An auxiliary agent may be added to the aqueous medium in order to well granulate the toner mother liquor in the aqueous medium containing the inorganic dispersant. Examples of such an auxiliary include known cation-type, anion-type and nonion-type surfactants, and anion-type surfactants are particularly preferable. For example, sodium alkylbenzene sulfonate, sodium α-olefin sulfonate, sodium alkyl sulfonate, and the like are preferably used in the range of 1 × 10 ^{−4 to} 0.1% by weight based on the toner mother liquor.

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. If the particle size of the dispersion-granulated toner mother liquor 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 develop an intermediate color, the melting and mixing properties become insufficient and the intermediate color appears. It becomes difficult. 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. Such homogenizers include TK homomixer, line flow homomixer (above, manufactured by Tokushu Kika Kogyo Co., Ltd.), Silverson homogenizer (manufactured by Silverson Co., Ltd.), Polytron homogenizer (manufactured by KINEMATICA AG, etc.).

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. Therefore, it is preferable to perform the removal under a temperature condition that is lower than the boiling point of the solvent and has a difference from the boiling point of the solvent of 80 ° C. or less. The pressure may be normal pressure or reduced pressure, but it is preferable that the pressure is reduced to 20 to 150 mmHg.

The solvent is preferably removed sufficiently until the particle shape of the granulated particles in the aqueous medium does not substantially change after the solvent is removed, and then the inorganic dispersant is preferably removed. In practice, it is preferable to remove 50% by weight or more, further 70% by weight or more, and especially 80% by weight or more of the total amount of the solvent charged. When the amount of the solvent to be removed is less than 50% by weight, the toner particles formed when the inorganic dispersant is removed coalesce with each other (a phenomenon in which the toner particles aggregate and become large particles), and the particle shape of the formed particles Is substantially changed, and it is difficult to obtain toner particles having a target particle diameter. The final toner particles have a residual solvent content of less than 1% by weight, particularly 0.5% from the viewpoints of environmental resistance, life at the time of mounting, and prevention of toner adhesion to the photoconductor.
It is preferable to control the content to be less than weight%. Therefore, a step of further removing the solvent by vacuum drying, vibration fluidization drying or the like may be provided.

The negatively chargeable toner of the present invention, after removing the solvent,
It is preferable to wash with an acid such as hydrochloric acid, nitric acid, formic acid or acetic acid which reacts with tricalcium phosphate or hydroxyapatite to solubilize these inorganic dispersants. As a result, the inorganic dispersant remaining on the surface of the toner can be removed, and the toner's original composition can be obtained. As a result, the charging characteristics of the toner can be maintained at a high level. In other words, by preventing the generation of undesired low-charged toner or reversely-charged toner, precise development can be performed on the electrostatic latent image, and image quality such as image density, resolution, gradation and fog can be improved. And shows excellent performance. Further, since the toner does not scatter, it does not pollute the working environment and is excellent in hygiene. Therefore, the toner and the developer can be repeatedly used for a long time and have a long life. Then, by dehydration and drying, powdery toner particles having an irregular shape can be obtained.

In order to further improve the physical properties such as fluidity and chargeability, the negatively charged toner for developing an electrostatic image of the present invention has the above-mentioned silica fine powder and vinyl (co) powder on the toner particle surface. Polymer, zinc stearate, aluminum oxide,
Fine particles such as titanium oxide 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 well-known materials such as iron oxide powder, various ferrites, and 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 negative-charge toner and developer for electrostatic image development of the present invention can be used in various known developing means and fixing means.

[0027]

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 temperature was raised to 230 ° C. to complete the reaction at the same temperature. The glass transition temperatures of the resins obtained are also shown in the table.

[0028]

[Table 1]

(2) Production of hydroxyapatite Hydroxyapatite used as an inorganic dispersant was produced by the following method. Trisodium phosphate dodecahydrate 391
An aqueous solution in which 166 parts by weight of calcium chloride was added dropwise to an aqueous solution in which 13 parts by weight of sodium hydroxide and 13 parts by weight of sodium hydroxide were added and reacted at 20 to 30 ° C. to obtain an aqueous solution containing 5% by weight of hydroxyapatite. . By adjusting the stirring speed and temperature, the average particle size is 1.0, 1.5, 2.
A 5% by weight aqueous solution of 0, 3.0 and 4.0 μm of various hydroxyapatite was prepared.

(3) Production of Toner A toner mother liquor was produced by dispersing the polyester resin, colorant (pigment), solvent and additives shown in Table 2 in a ball mill until the pigment particles became submicron. The toner mother liquor was granulated in a dispersion medium containing an 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 was adjusted within the range of 6 to 8 m / sec. Next, the solvent was distilled off under normal pressure to reduced pressure under the temperature condition that the temperature was lower than the boiling point of the solvent and the difference from the boiling point was 80 ° C. or less. When toluene is used as a solvent, the temperature is 50 to 70 ° C., the degree of reduced pressure is 30 to 150 mmHg, when methylene chloride is used, the temperature is 20 to 30 ° C., at atmospheric pressure, when methyl ethyl ketone is used, the temperature is 50 to 70 ° C. 80% by weight of toluene charged under a reduced pressure of 30 to 150 mmHg
Was desolvated. After cooling, 12N hydrochloric acid was added until the pH reached 2, the inorganic dispersant was washed away, washed with water, dried and classified to obtain a solid amorphous toner having an average particle size in the range of 4 to 8 μm. The amount of toluene remaining in the toner was measured by gas chromatography and found to be 0.1% by weight.
Then, the toner external additive shown in Table 2 was added to 100 parts by weight of the obtained toner, and the mixture was stirred and mixed by a Henschel mixer.

(4) Evaluation Copier recopy capable of printing 5% by weight of toner and 95% by weight of copper-zinc ferrite carrier coated with silicone resin and having an average particle size of 60 μm per minute at 65 sheets / A-4. Using (RICOPY) FT-7570 (manufactured by Ricoh Co., Ltd.), continuous printing was performed in an environment of 35 ° C. and 70% relative humidity, and image quality, workability, etc. were evaluated. The results are shown in Table 3.
Shown in. (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.

[0032]

[Table 2]

[0033]

[Table 3]

Example 7 The toners of Examples 1, 2 and 3 in Table 2 were put into Konica Digital Full Color 9028 (manufactured by Konica Corp.), and after adjusting the initial image, printing was carried out. It was reproduced and had good image quality. 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 subjected to pin mill and jet mill to obtain an irregular toner having an average particle diameter of 8 μm, and further 0.2 g of Aerosil R972 (manufactured by Nippon Aergil Co., Ltd.).
As a result of mixing in a Henschel mixer in an amount of 10% by weight, the color reproducibility was poor in the initial stage, 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 Except that the aqueous solution containing the inorganic dispersant of Example 1 was changed to an aqueous solution in which hydroxypropylmethyl cellulose (Metronose 90SH-10 1% aqueous solution manufactured by Shin-Etsu Chemical Co., Ltd.) was dissolved. A true spherical toner having an average particle diameter of 6 μm was obtained and the performance was evaluated.
Fog 0.1, resolution 6.3, toner scattering, cleanability
It was 0 (good) and was not stable to the environment. After printing 5,000 pages, the color tone reproducibility was poor (light is not transmitted), image density was 0.8, fog was 0.2, resolution was 4.0, toner was scattered, and 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.

Comparative Example 3 An aqueous solution containing the inorganic dispersant of Example 1 was treated with hydroxyapatite having an average particle size of 0.4 μm (Nippon Kagaku Co., Ltd.).
As a result of evaluation in exactly the same manner except that the toner was manufactured, the average particle diameter was as large as 20 μm, and an amorphous toner of 10 μm or less, which is the object of the present invention, was not obtained. When the initial performance was examined, the image density was 0.8, the fog was 0.08,
The resolution was 4.0, which was poor.

Comparative Example 4 The aqueous solution containing the inorganic dispersant of Example 1 was evaluated in the same manner except that hydroxyapatite having an average particle size of 6 μm was used. As a result, the average particle size was as large as 30 μm. The target amorphous toner having a particle size of 10 μm or less was not obtained. When the initial performance was examined, the image density was 0.8, the fog was 0.08, and the resolution was 4.0, which were poor.

[0038]

As is clear from the above results, the negative-charge toner and developer for developing an electrostatic charge image of the present invention maintain excellent image quality for a very long period of time.
Further, according to the method for producing a toner of the present invention, the above excellent toner can be obtained in a 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 (5)

[Claims] 1. A liquid obtained by dissolving or dispersing a toner material containing a polyester resin and a colorant in a solvent in which the polyester resin can be dissolved, has an average particle diameter of 0.7 to 5 μm.
A negative-charge toner for developing an electrostatic charge image, which is obtained by granulating in an aqueous medium containing the inorganic dispersant, and then removing the solvent. 2. The negatively charged toner for developing an electrostatic charge image according to claim 1, wherein the inorganic dispersant is tricalcium phosphate and / or hydroxyapatite. 3. A toner 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 the average particle size is 0.7
Production of a negatively chargeable toner for electrostatic image development, which comprises granulating into particles having a predetermined particle size under high-speed shearing into particles in an aqueous medium containing an inorganic dispersant of ˜5 μm, and then removing the solvent. Method. 4. The electrostatic charge image according to claim 3, wherein the solvent is sufficiently removed until the particle shape of the granulated particles does not substantially change thereafter, and then the inorganic dispersant is removed. Method for producing negatively charged toner for development. 5. A developer comprising the negatively chargeable toner according to claim 1 and a carrier.