JP2712264B2 - Toner for developing electrostatic latent images - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a toner for developing an electrostatic latent image.

Conventional technology and its problems Conventionally, a toner for developing an electrostatic latent image is prepared by melt-kneading a thermoplastic resin, a colorant, and other additives, pulverizing and classifying the kneaded material, so as to have a desired particle size distribution. Manufacturing.

However, it is difficult to reduce the particle size of such a pulverized classification type toner, and the shape of each toner is not constant and the fluidity is poor.

Today, with the widespread use of copiers, high-quality images and high-speed development are required.To meet these demands, toners must have a small particle size and high fluidity. It is difficult to meet these requirements with the pulverized and classified type toner.

Therefore, instead of the pulverized and classified type toner, a suspension polymerization toner capable of reducing the particle size and forming spherical particles has been proposed.

Suspension polymerized toner and the like have a spherical shape and therefore have good fluidity, and have a small particle size, and thus are suitable for forming high-quality images.

However, at the time of frictional charging of the toner, the contact probability with the carrier is reduced due to the shape thereof, and the frictional charging property is poor, and when cleaning the residual toner on the photoreceptor, the toner has a small particle diameter spherical shape, so that the toner is used as a cleaning blade. It is easy to slip through the photoconductor and has poor cleaning properties.

Further, from the viewpoints of high-speed development and energy saving, a toner that can be fixed at a low temperature is desired. However, such a toner is made of a resin having a low softening point, has no heat resistance, and has a problem of aggregation of the toner.

In addition to the above-mentioned problem, another property required for the toner is PVC resistance. In general, when a copy is stored in a sheet made of vinyl chloride or the like, there is a problem that the toner is eroded by the plasticizer in the sheet made of vinyl chloride and is fused to the sheet. It was remarkable in the toner as the main component. Therefore, it has been conventionally known that a polyester resin is used as a main component of the toner as a PVC-resistant toner.

However, polyester resins have polar groups (-CooH groups,-
(OH group), etc., the environment resistance was poor, and there was a problem in stabilizing the chargeability especially at high humidity.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and provides a toner that makes use of the characteristics of spherical particles and has excellent chargeability, cleaning properties, fixing properties, and especially low-temperature fixing properties. The purpose is to do.

Another object of the present invention is to provide a toner having excellent PVC resistance and environmental resistance.

Means for Solving the Problems That is, the present invention provides an electrostatic latent image developing toner in which fine particles are adhered and fixed in a wet manner on the surface of a core particle containing a colorant, wherein the core particle is at least a polyester resin. Is obtained by suspending and granulating the resin solution in an aqueous solution, and then removing the solvent.The fine particles are obtained by soap-free emulsion polymerization of a vinyl monomer and have an average particle size of The present invention relates to a toner for developing an electrostatic latent image, which has a thickness of 0.2 to 1.0 μm.

An electrostatic latent image developing toner having fine particles adhered and fixed to the surface of a core particle is formed by dissolving at least a polyester-based resin in a solvent, suspending and granulating the resin in an aqueous solution, and removing the solvent. The monomer is subjected to soap-free emulsion polymerization in an aqueous solution, and is obtained by adhering and fixing both particles using a water-soluble initiator.

Alternatively, an electrostatic latent image developing toner having fine particles adhered and fixed on the core particle surface is prepared by dissolving at least a polyester resin in a solvent, suspending and granulating the resultant in an aqueous solution, and removing the solvent by soap-free emulsification. Add vinyl polymer microparticles obtained by polymerization and adhere to the core particle surface, swell the microparticles when removing the solvent,
It is obtained by immobilization by completely removing the solvent.

The toner of the present invention has a structure in which fine particles are firmly adhered and fixed on the surface of the core particles, and irregularities are provided. The irregularities are formed by the fine particles covering the surface of the core particles while the spherical shape of the fine particles is maintained. Due to the unevenness of the toner of the present invention, the probability of contact with the carrier is increased, good chargeability is obtained, and the cleaning property of the toner is improved.

In the present invention, the core particles are formed of a polyester resin in order to impart PVC resistance. Further, in order to improve the environmental resistance of the polyester resin, the fine particles are formed of a vinyl resin.

Further, in the present invention, the core particles and the fine particles are made of the following materials having physical properties in order to impart both functions of fixing property and heat resistance.

In order to provide heat resistance, the microparticles are converted to a glass transition point (T
g) is a vinyl resin having a temperature of 55 to 150 ° C, preferably 60 to 120 ° C. When it is constituted by a material having a Tg lower than 55 ° C., heat resistance is inferior, and there is a problem of toner aggregation. When it is constituted by a material having a Tg higher than 150 ° C., fixability is deteriorated.

To give good fixability, softening point (Tm) of core particles
Is 70-180 ° C and the number average molecular weight (Mn) is 3000-2000
It is composed of a polyester resin having 0, preferably 4000 to 12,000.

The object and effect of the present invention can be achieved when all the above physical properties of the core particles and the fine particles are satisfied. If even one of the above physical properties is not satisfied, charging properties, cleaning properties,
Any of the problems of PVC resistance, environmental resistance, fixing property or heat resistance occurs.

In order to further improve the fixability of the toner, the resin of the core particles has a molecular weight distribution (Mw / Mn) represented by the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of 10 to 70, preferably 10 to 70. Adjust to ~ 50.

The core particles according to the present invention are produced by a suspension method. Suspension granulation involves uniformly dissolving and / or dispersing a polyester resin in a solvent having a low boiling point, granulating the solvent and a medium that does not dissolve the polyester resin with vigorous stirring, and stirring by heating and removing the solvent. The size of the particles generated under the conditions can be easily adjusted.

The size of the core particles is adjusted to an average particle size of 20 μm or less, preferably 2 to 15 μm. If it is larger than 20 μm, the image quality becomes coarse, and the chargeability also deteriorates.

The fine particles according to the present invention are produced, for example, by a soap-free emulsion polymerization method. The soap-free emulsion polymerization method is a formulation in which an emulsifier is removed from an emulsion polymerization system.Initiator radicals generated in the aqueous phase combine with slightly soluble monomers in the aqueous phase and eventually become insoluble to form particle nuclei. . Particles produced by this polymerization method generally have a larger particle size than emulsion polymerization, an average particle size of 0.2 to 1 μm, and a narrow particle size distribution.

In the present invention, fine particles having an average particle size of 0.2 to 1 μm are used as the fine particles to be attached to the surface of the core particles. Therefore, it is preferable to adjust the fine particles by a soap-free emulsion polymerization method.

As for the size of the fine particles, those having an average particle size of 0.2 μm to 1 μm, preferably 0.2 to 0.8 μm are used. If the average particle size of the fine particles is smaller than 0.2 μm, it is difficult to form such irregularities on the surface of the core particles for the purpose of the present invention. In addition, from the viewpoint of imparting heat resistance, the thickness of the fine particle layer is small, so that the object cannot be sufficiently achieved. When the average particle size of the fine particles is larger than 1 μm, it becomes difficult to uniformly attach the fine particles to the surface of the core particles, the surface coverage is reduced, and the toner cleaning property, durability, etc. are not sufficiently improved. When the purpose is to provide heat resistance, the particles are easily affected by the core particles.
Furthermore, because of the size of the fine particles, it becomes difficult to firmly adhere and fix the particles to the surface of the core particles.

In the electrostatic latent image developing toner of the present invention, the polyester resin used for the core particles is obtained by a polycondensation reaction between a diol having a bisphenol structure and a polycarboxylic acid or an anhydride thereof.

As the diol, polyoxypropylene (2,2)-
2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene (2,0) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (3,3) -2,2
-Bis (4-hydroxyphenyl) propane, polyoxypropylene (2,0) -polyoxyethylene, (2,0)-
2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (6) -2,2-bis (4-hydroxyphenyl) propane, polyoxystyrene (3) -bis (2,6-dibromo-4- Hydroxyphenyl) methane,
Polyoxybutylene (2,5) -bis (4-hydroxyphenyl) ketone, polyoxyethylene (3) -bis (4
-Hydroxyphenyl) ether, polyoxystyrene (2,8) -bis (2,6-digrom-4-hydroxyphenyl) thioether, polyoxyethylene (2,5) -bis (2,6-dibromo-4-hydroxy) Phenyl) sulfone, polyoxypropylene (3) -2,2-bis (2,6-difluoro-4-hydroxyphenyl) propane, polyoxypropylene (2,2) -2,2-bis (4-hydroxy-
2,6-dichlorophenyl) propane.

Examples of polycarboxylic acids include fumaric acid, maleic acid, phthalic acid, maleic anhydride, isophthalic acid, terephthalic acid, phthalic anhydride, trimellitic acid, trimellitic anhydride, alkyl succinic acid, alkenyl succinic acid, and the like. Can be Examples of the alkyl or alkenyl succinic acid include n-dodecenyl succinic acid, isododecenyl succinic acid, n-dodecyl succinic acid, isododecyl succinic acid, n-octyl succinic acid, n-butyl succinic acid and the like.

Preferred tricarboxylic acids include trimellitic acid (1,2,4-benzenetricarboxylic acid), toluene carboxylic acid, and cyclohexanetricarboxylic acid. As the tetracarboxylic acid, 4-neopentylidenyl-1,2 , 6,7-heptanetetracarboxylic acid, 4-neopentyl-1,2,6,7-heptene (4) -tetracarboxylic acid, 3-methyl-4-heptenyl-1,2,5,6-hexatetracarboxylic acid Acid, 3-methyl-3-heptyl-5-methyl-1,2,6,7-heptene (4) -tetracarboxylic acid, 3
-Nonyl-4-methylidenyl-1,2,5,6-hexanetetracarboxylic acid, 3-decylidenyl-1,2,5,6-hexanetetracarboxylic acid, 3-nonyl-1,2,6,7-heptene (4) -tetracarboxylic acid, 3-decenyl-1,2,5,6-
Hexanetetracarboxylic acid, 3-butyl-3-ethylenyl-1,2,5,6-hexanetetracarboxylic acid, 3-methyl-4-butylidenyl-1,2,6,7-heptanetetracarboxylic acid, 3-methyl 4-butyl-1,2,6,7-heptene (4) -tetracarboxylic acid, 3-methyl-5-octyl-1,2,6,7-heptene (4) -tetracarboxylic acid, and the like. Can be

 The polymerization is obtained by a generally known method.

Examples of the low boiling solvent that dissolves the polyester resin used in the present invention include dichloromethane, dichloroethane, trichloromethane, trichloroethane, methyl acetate, ethyl acetate, propyl acetate, methyl formate, ethyl formate, propyl formate, butyl formate, and methyl propionate. , Ethyl propionate, diethyl ether, dipropyl ether,
Benzene, toluene, xylene and the like can be used, and they may be used alone or as a mixture.

In the toner for developing an electrostatic latent image of the present invention, the vinyl resin used for the fine particles covering the core particles is not particularly limited, and may be a homopolymer or a copolymer of various vinyl monomers as shown below, and These polymer blends can be used, and desirably, a styrene-based polymer, a styrene- (meth) acryl-based copolymer, or the like is used.

Examples of the vinyl monomer include styrene, o-
Methylstyrene, m-methylstyrene, p-methylstyrene, p-ethylstyrene, 2,4-dimethylstyrene,
pn-butylstyrene, p-tert-butylstyrene,
pn-hexylstyrene, pn-octylstyrene, pn-nonylstyrene, pn-decylstyrene, pn-dodecylstyrene, p-methoxystyrene, p-methoxystyrene, p-phenylstyrene, p
Styrene and its derivatives such as -chlorostyrene and 3,4-dichlorostyrene, among which styrene is most preferred. As other vinyl monomers, for example, vinyl acetate, vinyl propionate, vinyl benzoate,
Vinyl esters such as vinyl butyrate, methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, n-acrylate
Octyl, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, α-methyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate , Isobutyl methacrylate, propyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate,
Α-ethylene aliphatic monocarboxylic acid esters such as diethylaminoethyl methacrylate, acrylonitrile,
(Meth) acrylic acid derivatives such as methacrylonitrile and acrylamide; vinyl ethers such as vinyl methyl ether, vinyl ethyl ether and vinyl isobutyl ether; vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone and methyl isopropenyl ketone; -Vinylpyrrole, N-vinylcarbazole, N
N- such as vinylindole and N-vinylpyrrolidone
Examples include vinyl compounds and vinyl naphthalenes.

As the colorant contained in the core particles in the toner for developing an electrostatic latent image of the present invention, various kinds of organic or inorganic pigments and dyes shown below can be used.

That is, examples of black pigments include carbon black, copper oxide, manganese dioxide, aniline, black, and activated carbon.

As the yellow pigment, there are yellow lead, sub-graphite, cadmium yellow, yellow iron oxide, mineral fast yellow, nickel titanium yellow, navel yellow, naphthol yellow S, banza yellow G, banza yellow 10G, benzidine yellow G, benzidine yellow GR , Quinoline Yellow Lake, Permanent Yellow NCG, Tartrazine Lake etc.

As the orange pigment, red lead, molybdenum orange,
Permanent Orange GTR, Pyrazolone Orange, Vulcan Orange, Indus Len Brilliant Orange RK,
Benzidine Orange G and Indus Len Brilliant Orange GK.

Red pigments include red iron, cadmium red, lead red, mercury sulfide, cadmium, permanent red 4R, lithol red, pyrazolone red, watching red, calcium salt, lake red D, brilliant carmine 6B, eosin lake, rhodamine lake B, Alizali Shirake, Brilliant Carmine 3B and others.

Examples of purple pigments include manganese purple, fast violet B, and methyl violet lake.

Examples of the blue pigment include navy blue, cobalt blue, alkali blue lake, Victoria blue lake, phthalocyanine blue, metal-free phthalocyanine blue, partially chlorinated phthalocyanine blue, fast sky blue, and indaslen blue BC.

Green pigments include chrome green, chromium oxide, pigment green B, micalite green lake, final yellow green G, and the like.

Examples of white pigments include zinc white, titanium oxide, antimony white, and zinc sulfide.

The extender includes baryte powder, barium carbonate, clay, silica, white carbon, talc, alumina white and the like.

Various dyes such as basic, acidic, acidic and direct dyes include nigrosine, methylene blue, rose bengal, quinoline yellow, and ultramarine blue.

These colorants can be used alone or in combination.

Further, in order to improve the developability, a magnetic powder such as magnetite, various ferrites, iron, cobalt and nickel may be added.

In the present invention, core particles and / or fine particles,
Preferably, the fine particles may contain an anti-offset agent.

Examples of the anti-offset agent to be contained in the core particles or fine particles of the present invention include polyolefin waxes, for example, low-molecular-weight polypropylene, low-molecular-weight polyethylene, oxidized polypropylene, and oxidized polyethylene.

Specific examples of the polyolefin wax include, for example, Hoechst Wax PE520, Hoechst Wax PE130, Hoechst
Wax PE190 (manufactured by Hoechst), Mitsui High Wax 200, Mitsui High Wax 210, Mitsui High Wax 210M, Mitsui High Wax 220, Mitsui High Wax 220M (manufactured by Mitsui Petrochemical Industries), Sun Wax 131-P, Sun Wax 151 −
Non-oxidizing polyethylene wax such as P, Sunwax 161-P (manufactured by Sanyo Chemical Industries), Hoechst Wax PE
D121, Hoechst Wax PED153, Hoechst Wax PED521, Hoec
hst Wax PED522, Ceridust3620, Ceridust VP130, Ceri
dust VP5905, Ceridust VP9615A, Ceridust TM9610F
(Manufactured by Hoechst), Mitsui High Wax 420M (manufactured by Mitsui Petrochemical Industries), Sunwax E-300, Sunwax E
Oxidized polyethylene wax such as -250P (manufactured by Sanyo Chemical Industries), Hoechist Wachs PP230 (manufactured by Hoechst), Viscol 330-P, Viscol 550-P, Viscol 660-P (manufactured by Sanyo Chemical) And non-oxidized polypropylene wax, and oxidized polypropylene wax such as Viscol TS-200 (manufactured by Sanyo Chemical Industries, Ltd.).

As the wax used in the present invention, those having a number average molecular weight (Mn) of 1,000 to 20,000 and a softening point (Tm) of 80 to 150 ° C are used. When Mn is 1000 or less or Tm is 80 ° C or less, uniform dispersion of the resin component in the core particles and fine resin particles cannot be performed, and only the wax component is eluted on the toner surface, and the toner is stored or developed during storage or development. This is because not only may undesirable results be caused, but also photoconductor contamination such as filming may be caused. On the other hand, when Mn exceeds 20,000 or Tm exceeds 150 ° C., not only does the compatibility with the resin deteriorate, but also the effect of containing a wax such as a hot offset resistance method cannot be obtained.

The wax component is particularly preferably added to the fine particles, and the amount added to the fine resin particles is preferably 0.1 to 20% by weight, more preferably 1 to 15% by weight of the total weight of the fine resin particles. That is, if the added amount is less than 0.1% by weight, a sufficient offset prevention effect cannot be exhibited, while
If the addition amount exceeds 20% by weight, uniform dispersion of the resin component in the fine resin particles cannot be achieved, and only the wax component is eluted on the toner surface, resulting in unfavorable results during storage or development of the toner. This is not only because there is a possibility that the photoconductor may be contaminated such as filming. Even when the amount of the wax component added is close to 20% by weight of the fine resin particles, the amount of the wax component with respect to the entire toner particles is still small, and the image quality is excessively increased due to the high blending of the wax component. There is no problem such as glossiness.

Polyolefin waxes include other waxes such as synthetic hydrocarbon waxes such as Fischer-Tropsch wax; vegetable waxes such as candelilla wax, carnauba wax, rice wax, water wax, jojoba oil; paraffin wax, microcrystalline wax, Petroleum waxes such as petrolactam; modified waxes such as montan wax derivatives, paraffin wax derivatives, and microcrystalline wax derivatives; silicone oils such as dimethyl silicone oil and phenylmethyl silicone oil; other various fatty acids, acid amides, acid imides , Esters, ketones, and other synthetic waxes, as well as blends of these various waxes.

As the charge control agent that can be used in the present invention, either a positively chargeable or a negatively chargeable charge control agent can be used, and the charge control agent is selected depending on the use of the toner.

Examples of the positively charged positive charge control agent include Nigrosine Base EX (manufactured by Orient Chemical Co., Ltd.) Quaternary ammonium salt P-51 (manufactured by Orient Chemical Co., Ltd.) Nigrosine Bontron N-01 (manufactured by Orient Chemical Co., Ltd.) Sudan Chief Schwarz BB (Solvent Black 3: Color Index 26150) Fettschwarz HBN (CINO. 26150) Brilliant Spirits Schwarz TN (Falben Fabriken Bayer) Savon Schwarz X (Falberge Hoechst) Especially alkoxylated amines , Alkyl amides, molybdic acid chelate pigments, and the like. The negative charge control agents include Oil Black (Color Index 26150), Oil Black BY (manufactured by Orient Chemical Co., Ltd.) Bontron S-22 (Orient Chemical Co., Ltd.) ) Manufactured) salicylic acid metal complex E-81 Orient Chemical Co., Ltd.) Theoindigo pigment Sulfonylamine derivative of copper phthalone cyanine Spiron Black TRH (Hodogaya Chemical Co., Ltd.) Bontron S34 (Orient Chemical Co., Ltd.) Nigrosine SO (Orient Chemical Co., Ltd.) Celes Schwarz (R) G (Farben Fabriken Bayer) Chromogen Schwarz ETOO (CINO.14645) Azo Oil Black (R) (National Aniline).

When the fine resin particles are neutral to the carrier,
It is desirable to add a charge control agent to the fine resin particles.

These charge control agents can be used alone or in combination of two or more, but the amount of the charge control agent added to the fine particles constituting the outer shell layer is 100 parts by weight of the synthetic resin forming the fine particles. 0.001 to 10 parts by weight, preferably 0.01 to 5 parts by weight. That is, if the addition amount is less than 0.001 part by weight, the amount of the charge control agent present on the surface of the toner particles is small, so that the charge amount of the toner is insufficient.
If the amount is more than 10 parts by weight, the charge controlling agent may be peeled off from the outer shell layer, spent on the surface of the carrier, or mixed into the developer to deteriorate printing durability.

To adhere and fix the fine particles on the surface of the core particles, a predetermined amount of the core particles and the fine particles are dispersed in an aqueous solution, and a water-soluble polymerization initiator is added.

The fine particles form an outer shell layer of the core particles, and the added amount of the fine particles is 5 to 40 parts by weight, preferably 10 to 30 parts by weight based on 100 parts by weight of the core particles. If the added amount of the fine particles is less than 5 parts by weight, the surface of the core particles cannot be completely covered, which has an adverse effect on heat resistance, cleaning properties, and chargeability. No fine particles adversely affect fluidity and chargeability.

Examples of water-soluble polymerization initiators include ammonium persulfate, potassium persulfate, 2,2'-azobis (N, N'-dimethyleneisobutyroamidine) hydrochloride, and 2,2'-azobis (2-amidinopropane) hydrochloride , Ferrous sulfate or hydrogen peroxide.

The microparticles can be attached to the surface of the core particles only by mixing and stirring both the core particles and the microparticles.However, if a water-soluble polymerization initiator is used, the adhesion can be further strengthened, and drying and classification can be performed. The fine particles can be fixed so as not to be detached from the surface of the core particles. One possible reason is that the water-soluble initiator initiates the polymerization of the unreacted monomer of the fine particles, and the two particles are molecularly bonded via a polymerization reaction.

Conditions for attaching and fixing the microparticles on the surface of the core particles, for example, the amount of the water-soluble initiator, the temperature, the reaction time, etc. are determined by the type of the monomer used for forming the core particles and the microparticles, the radical polymerization initiator. Considering various conditions such as the reaction time and the like, the conditions under which the particles can be firmly adhered and fixed to the extent that they are not adversely affected by the detachment of the fine particles from the core particles during actual use may be appropriately selected.

The toner of the present invention can be mixed with a suitable carrier to form a two-component developer. Known carriers can be used as the carrier, and the toner is usually blended at a ratio of 3 to 12% by weight of the developer.

A fluidizing agent may be added (externally added) to the toner of the present invention in order to improve fluidity. Examples of the fluidizing agent include silica, aluminum oxide, titanium oxide, a mixture of silica and aluminum oxide, and a mixture of silica and titanium oxide.

Further, a metal soap such as zinc stearate may be externally added to improve the cleaning property.

 Hereinafter, the present invention will be described with reference to examples.

Manufacturing Method of Core Particles Manufacturing of Core Particles A 100 g of a polyester resin (manufactured by NE-382 Kao Corporation) is dissolved in 400 g of a mixed solvent of methylene chloride / toluene (8/2), and carbon black MA ^{# 8} (Mitsubishi) (Manufactured by Kasei Co., Ltd.)
5 g was placed in a ball mill and mixed and dispersed for 3 hours to obtain a uniform mixed dispersion. Next, 60 g of a 4% solution of methylcellulose (Methocel K35LV: manufactured by Dow Chemical Company) as a dispersion stabilizer,
Dioctyl sulfosuccinate soda (Nikkor OTP
-75: 5 g of a 1% solution in Nikko Chemical Co., Ltd., and 0.5 g of sodium hexametaphosphate (manufactured by Wako Pure Chemical Industries) in 1000 g of ion-exchanged water. The number of revolutions of the homojetter was adjusted to 12 μm, and the suspension was suspended in water. The suspension was transferred to a four-necked flask, and the mixed solvent of methylene chloride / toluene was removed at a temperature of 70 ° C. and a stirring speed of 100 rpm for 5 hours to obtain spherical core particles A having a solid content of 10% and an average particle diameter of 8 μm. Obtained.

Production of Core Particles B Spherical core particles B having a solid content of 10% and an average particle diameter of 8 μm were obtained in the same manner as in Production Example A except that the phthalocyanine pigment was changed to 6 g instead of carbon black.

Production of Core Particle C 100 g of a polyester resin (Vylon 200 Toyobo) is dissolved in 400 g of methylene chloride, and 10 g of carbon black MA # 8 (manufactured by Mitsubishi Kasei Co., Ltd.)
0%, spherical core particles C having an average particle size of 8 μm were obtained.

Production method of microparticles Production of microparticles a Dissolve 0.4 g of ammonium persulfate in 800 g of ion-exchanged water, transfer to a four-necked flask, and replace with nitrogen at 75 ° C.
The solution dissolved in 200 g of methyl methacrylate and 8 g of methacrylic acid was added thereto, and polymerized at a stirring speed of 300 rpm for 6 hours to obtain uniform particles a having an average particle diameter of 0.2 μm. The glass transition point of the fine particles a was 108 ° C.

Preparation of microparticle b 2,2'-azobis (2-amidinopropane) dihydrochloride
0.3 g was dissolved in 800 g of ion-exchanged water, transferred to a four-necked flask, heated to 70 ° C. while purging with nitrogen, charged with 200 g of methyl methacrylate, and stirred at 200 rpm.
And polymerize for 3 hours to obtain uniform particles b having an average particle size of 0.4 μm.
I got The glass transition point of the fine particles b was 105 ° C.

Production of microparticles c Dissolve 0.2 g of ammonium persulfate in 800 g of ion-exchanged water, transfer to a four-necked flask, and replace with nitrogen at 70 ° C.
And 200 g of styrene was added dropwise from the dropping funnel over 2 hours. After the addition was completed, polymerization was carried out for 4 hours.
m uniform particles c were obtained. The glass transition point of the fine particles c is 10
5 ° C.

Production of microparticles d In a nitrogen-substituted four-necked flask, 760 g of ion-exchanged water was added to 200 g of a slurry containing 20% of 0.4 μm microparticles b, and 2,2-azobisisobutyro was stirred at 300 rpm. After 280 g of methyl methacrylate containing 3 g of nitrile was added dropwise over 1 hour, the mixture was kept at 70 ° C. for 6 hours to obtain uniform particles d having an average particle diameter of 1.2 μm. Glass transition point of microparticle d is 105 ℃
Met.

Production of Fine Particles e In the production method of the fine particles a, the stirring speed during granulation
Except for 1000 rpm, the average particle size is 0.1 μm by the same composition method.
Was obtained. The glass transition point of the fine particles e is 108
° C.

Production Example of Toner Production of Toner 1 170 g of a 20% slurry of fine particles a was added to 800 g of a 10% slurry of core particles A, and dispersed in 1000 g of ion-exchanged water.
5 g of ammonium persulfate was added. The dispersion was transferred to a four-necked flask, reacted at 70 ° C. under a nitrogen purge at a stirring speed of 160 rpm for 5 hours, washed with filtered water, dried, and average particle size of 10 to 20 μm.
m resin microspheres were obtained.

The obtained particles were further subjected to air classification to obtain a toner 1 having an average particle size of 10 μm.

Production of Toners 2 to 8 In production of Toner 1, core particles and fine particles are shown in Table 1.
The toners 2 to 7 were obtained in the same manner as in the production of the toner 1, except that the toners were changed as shown in (1).

In addition, the toner 8 does not adhere fine particles,
Only the core particles A were used as a toner.

Example of carrier production (binder type carrier) The above materials were sufficiently mixed and pulverized by a Henschel mixer, and then melted and kneaded using an extruder kneader set at a cylinder portion of 180 ° C. and a cylinder head portion of 170 ° C. After cooling, the kneaded product was finely pulverized with a jet mill, and then classified using a classifier to obtain a magnetic carrier having an average particle size of 55 μm.

Evaluation of Various Properties The predetermined toners 1 to 8 shown in Table 1 and the above carrier were mixed at a toner / carrier ratio of 7/93, and the toner was further mixed.
Post-processing was performed with 0.1 part by weight of colloidal silica R-972 (manufactured by Nippon Aerosil Co., Ltd.) per 100 parts by weight to prepare a two-component developer, and the following evaluation was performed.

Note that EP-570Z (manufactured by Minolta Camera Co., Ltd.) is used for the developer in combination with the one-charge toner, and EP-470Z (manufactured by Minolta Camera) is used for the developer in combination with the + chargeable toner. The evaluation was carried out.

Printing durability test A printing durability test of 10,000 sheets was performed using the above-described developer.

At this time, the toner charge amount and the cleaning property were evaluated,
The results are shown in Table 2. The cleaning performance was visually ranked according to the difference in the degree of poor cleaning on the image. ○ indicates that cleaning failure did not occur, including during printing, Δ indicates that cleaning failure did not initially occur, but cleaning failure occurred during printing, and × indicates that cleaning failure occurred initially. Is shown.

Environmental resistance test Toner stored at room temperature (temperature 18 to 25 ° C, humidity 30 to 60%) and high temperature and high humidity environment (temperature 35 ° C, humidity 85%)
And the charge amount of the toner after storage for 24 hours was measured at room temperature, and the comparison results are shown in Table 3. In the table, .largecircle. Indicates that there is almost no change in the charge amount due to the environment, and X indicates that the charge amount changed greatly (4 to 8 .mu.c / g), and that toner scattering was observed.

Heat resistance test Put 5g of each toner in 50cc poly bottle, 24 hours in 50 ℃ environment
Judgment was made based on the cohesiveness after storage for a time, and ranking was performed. Although practically possible with Δ or more, ○ is a preferable range (Table 3).

PVC resistance test The PVC resistance test was conducted by overlaying a vinyl chloride resin sheet containing 50% by weight of dioctyl phthalate manufactured by Mitsui Toatsu Chemicals Co., Ltd. with the image side of the copy paper, and setting the 1 kg / cm ² at 35 ° C. in an oven. After leaving it under pressure for 24 hours, take it out and peel it off.Observe the state of transfer of the toner to the sheet.If there is no change in the copied image and no toner transfer at all, the toner is transferred to the sheet. What was observed was evaluated as x.

Effects of the Invention The toner of the present invention has excellent chargeability, cleaning properties, PVC resistance, environmental resistance, fixing properties and heat resistance.

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-61-118758 (JP, A) JP-A-60-188682 (JP, A) JP-A-63-501040 (JP, A) International publication 87/1828 (WO, A1)

Claims (1)

(57) [Claims] 1. A toner for developing an electrostatic latent image comprising fine particles adhered and fixed on a surface of a core particle containing a colorant in a wet process, wherein said core particle dissolves at least a polyester-based resin in a solvent, After suspension granulation of the solution in the aqueous solution,
A toner for developing an electrostatic latent image, wherein the toner is obtained by removing a solvent, wherein the fine particles are obtained by soap-free emulsion polymerization of a vinyl monomer and have an average particle size of 0.2 to 1.0 μm.