JPH0814723B2 - toner - Google Patents

Description

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 obtained by melt-kneading a thermoplastic resin, a colorant, and other additives, and pulverizing and classifying the kneaded product so that a desired particle size distribution is obtained. Manufacturing.

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

With the widespread use of copiers today, high-quality images and high-speed development are required. To meet these requirements, toners must have a small particle size and high fluidity. It is difficult to meet these demands with the pulverized and classified toner of (1).

Therefore, in place of the pulverizing / classifying type toner, a suspension polymerization toner is proposed, in which the particle size can be reduced and the particles are formed into a spherical shape.

The suspension-polymerized toner has a spherical shape and thus has good fluidity, and since the spherical shape is small, it is suitable for high-quality image formation.

However, when the toner is triboelectrified, the contact probability with the carrier is reduced due to its shape, and the triboelectrification property is poor, and when cleaning the residual toner on the photoconductor, the toner has a small particle diameter, and therefore the toner is not compatible with the cleaning blade. It easily slips between the photoconductor and is inferior in cleaning property.

Further, the pulverized toner usually contains an offset preventive agent such as wax in order to prevent high temperature offset. In the suspension polymerization toner, an offset inhibitor such as wax is added during suspension polymerization, and the offset inhibitor is incorporated in the bulk of the suspension polymer particles. Therefore, the offset preventive agent does not work effectively, high-temperature offset is likely to occur, and the fixability of the toner is poor.

Further, from the viewpoint of high-speed development and energy saving, a toner that can be fixed at a low temperature is desired, but such a toner is composed of a resin having a low softening point, has no heat resistance, and causes problems such as aggregation of the toner.

The present invention is made in view of the above problems,
It is an object of the present invention to provide a toner which takes advantage of the characteristics of suspension-polymerized particles and is excellent in charging property, cleaning property, offset prevention, and particularly high temperature offset prevention.

Means for Solving the Problem That is, the present invention is a soap-free emulsification of a vinyl-based monomer in an aqueous solution on a core particle surface obtained by suspension-polymerizing a vinyl-based monomer containing at least a colorant in an aqueous solution. The present invention relates to a toner comprising fine particles which have been polymerized and which contain at least an offset preventive agent, and both particles are adhered and fixed by using a water-soluble polymerization initiator.

The toner of the present invention has a structure in which fine particles are firmly adhered and fixed on the surface of core particles to give unevenness. The irregularities are formed by coating the surfaces of the core particles with the fine particles while maintaining the spherical shape of the fine particles. 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 toner cleaning property is improved.

The core particles are formed by the suspension polymerization method. The suspension polymerization method is a method of radically polymerizing by adding an initiator soluble in the monomer while strongly stirring the polymerizable monomer with a medium in which the monomer is not dissolved. The size of can be easily adjusted.

The fine particles are produced 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 bond with a slightly soluble monomer in the aqueous phase and eventually become insoluble to form a particle nucleus. Particles produced by this polymerization method generally have a larger particle size (0.2 to 1 μm) than emulsion polymerization and have a narrow particle size distribution. In the soap-free emulsion polymerization method, the suspension polymerization method is a method in which a monomer having a low solubility in a dispersion medium (usually water) is dispersed in the dispersion medium by stirring, and a polymerization initiator (oil-soluble Polymerization proceeds in each dispersed oil droplet using an initiator); a dispersion stabilizer such as a surfactant is used in order to prevent coalescence between particles during polymerization; particle size is 1-100 μm or more They differ in that the distribution is wide.

In the soap-free polymerization method, the point that the particle size can be controlled in the range of 0.1 μm to 1 μm is a point that cannot be achieved by the suspension polymerization method. To attach the fine particles to the surface of the core particles, Since the property is required, it is prepared by a soap-free emulsion polymerization method.

In addition to the monomer and the polymerization initiator, various other desired additives are added during the preparation of the core particles, and similarly, an offset inhibitor, a charge control agent, and various other desired additives are added during the preparation of the fine particles. The anti-offset agent and the charge control agent may be added also in the core particles, but the effect is not sufficiently obtained, and by incorporating them in the fine particles according to the present invention, the original function of those additives is exerted. Toner can be obtained. In particular, when the anti-offset agent is contained in the fine particles, its function can be effectively utilized.

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 and chargeability are poor.

The size of the fine particles has an average particle size of 0.1 μm to 1.0 μm,
Preferably 0.2-0.8 μm, more preferably 0.2-0.6 μm
Use one. When the average particle size of the fine particles is smaller than 0.1 μm, it is difficult to form such irregularities on the surface of the core particles for the purpose of the present invention, and it becomes difficult to contain an effective amount of an offset inhibitor or the like. Further, when the purpose is to impart heat resistance, the purpose cannot be sufficiently achieved because the fine particle layer is thin. 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 lowered, and the toner cleaning property, durability, etc. are not sufficiently improved. For the purpose of imparting heat resistance, the particles are likely to be affected by the core particles. Furthermore, because of the size of the fine particles, it becomes difficult to firmly attach and fix the particles to the surface of the core particles.

For the preparation of the core particles and the fine particles of the present invention, the same monomers can be used, and examples of such monomers include vinyl monomers, such as styrene,
o-methylstyrene, m-methylstyrene, p-methylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, pn-butylstyrene, p-tert-butylstyrene, pn-hexylstyrene, p- n-octylstyrene, pn-nonylstyrene, pn-decylstyrene, pn-dodecylstyrene, p-methoxystyrene, p-ethoxystyrene, p-phenylstyrene, p
Examples thereof include styrene such as chlorostyrene and 3,4-dichlorostyrene and derivatives thereof, and among them, styrene is most preferable. Other vinyl-based monomers include, 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, methyl α-chloroacrylate, 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-methylene aliphatic monocarboxylic acid esters such as diethylaminoethyl methacrylate, acrylonitrile,
(Meth) acrylic acid derivatives such as methacrylonitrile 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, N- Vinylpyrrole, N-vinylcarbazole, N
-N- such as vinylindole and N-vinylpyrrolidone
Vinyl compounds and vinyl naphthalenes can be mentioned. In addition, as a synthetic resin used for the core particles, these vinyl monomers may be a homopolymer used alone or a copolymer in which a plurality of vinyl monomers are combined.

Further, as the vinyl monomer, a monomer having a nitrogen-containing polar functional group or a monomer component having fluorine can be used alone or in combination with the above-mentioned monomers. When microparticles are composed of such a polar group-containing monomer, the microparticles themselves serve to control the charge, and therefore the charge control agent has a desired chargeability in a smaller amount than that contained in the core particles. It is possible to give.

The nitrogen-containing polar functional group is effective for positive charge control, and as the monomer having the nitrogen-containing polar functional group, the following general formula (I) is used. (Wherein R ₁ is hydrogen or a methyl group, R ₂ and R ₃ are hydrogen or an alkyl group having 1 to 20 carbon atoms, X is an oxygen atom or a nitrogen atom, and Q is an alkylene group or an arylene group). There are amino (meth) acrylic monomers that are used.

Representative examples of amino (meth) acrylic monomers include N, N-dimethylaminomethyl (meth) acrylate, N, N-diethylaminomethyl (meth) acrylate, N, N-dimethylamino (meth) acrylate, and N, N. −
Diethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, N, N-dimethylaminobutyl (meth) acrylate, p-N, N-
Dimethylaminophenyl (meth) acrylate, p-N,
N-diethylaminophenyl (meth) acrylate, p
-N, N-dipropylaminophenyl (meth) acrylate, p-N, N-dibutylaminophenyl (meth) acrylate, p-N-laurylaminophenyl (meth) acrylate, p-N-stearylaminophenyl (meth)
Acrylate, p-N, N-dimethylaminobenzyl (meth) acrylate, p-N, N-diethylaminobenzyl (meth) acrylate, p-N, N-dipropylaminobenzyl (meth) acrylate, p-N, N- Examples thereof include dibutylaminobenzyl (meth) acrylate, p-N-laurylaminobenzyl (meth) acrylate and p-N-stearylaminobenzyl (meth) acrylate. Furthermore, N, N-dimethylaminoethyl (meth) acrylamide, N, N-diethylaminoethyl (meth) acrylamide, N, N-dimethylaminopropyl (meth) acrylamide, N, N-diethylaminopropyl (meth)
Acrylamide, p-N, N-dimethylaminophenyl (meth) acrylamide, p-N, N-diethylaminophenyl (meth) acrylamide, p-N, N-dipropylaminophenyl (meth) acrylamide, p-N, N- Dibutylaminophenyl (meth) acrylamide, p-N
-Laurylaminophenyl (meth) acrylamide, p
-N-stearylaminophenyl (meth) acrylamide, p-N, N-dimethylaminobenzyl (meth) acrylamide, p-N, N-diethylaminobenzyl (meth)
Acrylamide, p-N, N-dipropylaminobenzyl (meth) acrylamide, p-N, N-butylaminobenzyl (meth) acrylamide, p-N-laurylaminobenzyl (meth) acrylamide, p-N-stearylaminobenzyl (Meth) acrylamide etc. are illustrated.

Fluorine atom is effective for negative charge control, there is no particular limitation as a fluorine-containing monomer, for example, 2,2,2-trifluoroethyl acrylate, 2,2,3,3-tetrafluoropropyl acrylate, 2,2 Preferred examples include fluoroalkyl (meth) acrylates such as 1,3,3,4,4,5,5-octafluoroamyl acrylate and 1H, 1H, 2H, 2H-heptadecafluorodecyl acrylate. In addition, trifluorochloroethylene, vinylidene fluoride, ethylene trifluoride, tetrafluoroethylene, trifluoropropylene, hexafluoropropene, hexafluoropropylene and the like can be used.

The fine resin adhered to the surface of the core particles may be the same as or different from the resin forming the core particles, but the functional separation by the core particles and the fine particles (for example, It can be made of different materials in order to achieve fixability and heat resistance. For example, when heat resistance is desired, the core particles and the fine particles are made of a resin having desired heat resistance. In order to obtain a better fixing property, in particular, to obtain a toner having a good low-temperature fixing property, by configuring the core particles with a low softening point resin and the fine particles with a heat-resistant resin, It is possible to prepare a toner having both fixing property and heat resistance.

From the viewpoint of imparting heat resistance, the glass transition point (Tg) of the soap-free emulsion-polymerized resin forming the fine particles is 60 to 15
It is preferably 0 ° C.

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

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

Yellow pigments include yellow lead, zinc yellow, cadmium yellow, yellow iron oxide, mineral fast yellow, nickel titanium yellow, navel yellow, naphthol yellow S, bunzer yellow G, bunzer yellow 10G, benzidine yellow G, benzidine yellow GR, There are quinoline yellow rake, permanent yellow NCG and tartrazine rake.

Orange pigments include red yellow lead, molybdenum orange,
Permanent Orange GTR, Pyrazolone Orange, Balkan Orange, Induslen Brilliant Orange RK,
Benzidine orange G, indanthrene brilliant orange GK and others.

Examples of red pigments include red iron oxide, cadmium red, red lead, mercury sulfide, cadmium, permanent red 4R, resole red, pyrazolone red, watching red, calcium salt, lake red D, brilliant carmine 6B, eosin lake, rhodamine lake B, Alizarin Rake, Brilliant Carmine 3B and others.

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

Examples of blue pigments include navy blue, cobalt blue, alkali blue lake, Victoria blue lake, phthalocyanine blue, metal-free phthalocyanine blue, phthalocyanine blue partially chlorinated compound, fast sky blue, and indanthrene blue BC.

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

White pigments include zinc white, titanium oxide, antimony white, and zinc sulfide.

Examples of extender pigments include barite powder, barium carbonate, clay, silica, white carbon, talc, and alumina white.

Further, various dyes such as basic, acidic, disperse 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, magnetic powders such as magnetite, various ferrites, iron, cobalt and nickel may be added.

Examples of the offset preventive agent to be contained in the fine particles of the present invention include polyolefin waxes such as low molecular weight polypropylene, low molecular weight polyethylene, oxidized polypropylene, oxidized polyethylene and the like.

Specific examples of the polyolefin wax include, for example, Hoechst Wax PE520, Hoechst Wax PE130, Hoechst.
Wax PE190 (Made by Hoechst), Mitsui High Wax 200, Mitsui High Wax 210, Mitsui High Wax 210M, Mitsui High Wax 220, Mitsui High Wax 220M (Mitsui Petrochemical Industry Co., Ltd.), Sun Wax 131-P, Sun Wax 151 −
Hoechst Wax PE, non-oxidizing polyethylene wax such as P, Sun Wax 161-P (manufactured by Sanyo Kasei Co., Ltd.)
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), Sun Wax E-300, Sun Wax E
-250P (manufactured by Sanyo Chemical Industry Co., Ltd.) and other oxidized polyethylene waxes such as Hoechist Wachs PP230 (manufactured by Hoechst Co.), Viscole 330-P, Viscole 550-P, Viscole 660-P (manufactured by Sanyo Chemical Industry Co., Ltd.) Examples thereof include non-oxidizing polypropylene wax, and oxidative polypropylene wax such as Piscol TS-200 (manufactured by Sanyo Kasei Co., Ltd.).

From the viewpoint of compatibility, when used with a resin having a polar group, a wax having a polar group is desirable.

The wax used in the present invention has a number average molecular weight (Mn) of 1000 to 20000 and a softening point (Tm) of 80 to 150 ° C. When Mn is 1000 or less or Tm is 80 ° C. or less, it is not possible to uniformly disperse the resin component in the fine resin particles, and only the wax component is eluted on the toner surface,
This is because not only unfavorable results may occur during storage or development of the toner, but also contamination of the photoreceptor such as filming may occur. Also, Mn
When the Tm exceeds 20,000 or the Tm exceeds 150 ° C., not only the compatibility with the resin deteriorates, but also the effect of incorporating a wax such as a high temperature offset resistance method cannot be obtained.

The amount of the wax component added to the fine resin particles is 0.1 to 20% by weight of the total weight of the fine resin particles, more preferably 1 to 15%.
It is preferably in the weight%. That is, the addition amount is 0.1
If it is less than 10% by weight, the offset preventing effect cannot be sufficiently exerted. On the other hand, if it is more than 20% by weight, the resin component in the fine resin particles cannot be uniformly dispersed and the wax is not formed on the toner surface. This is because not only the components may be eluted to cause unfavorable results at the time of storing or developing the toner, but also the photoconductor may be contaminated such as filming. Even if the addition amount of the wax component 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 excessive blending of the wax component results in excessive image quality. There is no problem such as gloss.

Polyolefin wax is other wax, for example, synthetic hydrocarbon wax such as Fischer-Tropsch wax; plant wax such as candelilla wax, carnauba wax, rice wax, wax, jojoba oil; paraffin wax, microcristan wax, Petroleum-based waxes such as petrilactam; modified waxes such as montan wax derivatives, paraffin wax derivatives, and microcristan wax derivatives; silicone oils such as dimethyl silicone oil and phenylmethyl silicone oil; other various fatty acids, acid amides, acid imides It may be used together with synthetic waxes such as compounds, esters and ketones, and blends of these various waxes.

As the charge control agent that can be used in the present invention, either a positive charge type or a negative charge type charge control agent can be used, and the charge control agent is selected according to the intended use of the toner.

Examples of the 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) Priliant Spirits Schwarz TN (Falben Fabriken Bayer) Savon Schwarz X (Falberge Hoechst) In particular, alkoxy Amines, alkylamides, molybdic acid chelate pigments, and the like. Examples of the negative charge control agent include Oil Black (Color Index 26150), Oil Black BY (manufactured by Orient Chemical Co., Ltd.) Bontron S-22 (Orient Chemical Co., Ltd.) Salicylic acid metal complex E-81 (Manufactured by Orient Chemical Co., Ltd.) Theoindigo pigment sulfonylamine derivative of copper phthalocyanine Spiron Black TRH (manufactured by Hodogaya Chemical Co., Ltd.) Bontron S34 (manufactured by Orient Chemical Co., Ltd.) Nigrosine SO (manufactured by Orient Chemical Co., Ltd.) Ceres Schwarz (R) G (manufactured by Farben Fabriken Bayer) Chromogen Schwarz ETOO (CINO.14645) Azo Oil Black (R) (manufactured by National Aniline).

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

These charge control agents can be used alone or in combination of two or more kinds, but the addition 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. To 0.001 to 10 parts by weight, preferably 0.01 to 5 parts by weight. That is, when the addition amount is less than 0.001 parts by weight, the amount of the charge control agent present on the surface portion of the toner particles is small, so that the toner charge amount is insufficient, while
This is because if the amount exceeds 10 parts by weight, the charge control agent may be peeled off from the outer shell layer and may be spent on the surface of the carrier or may be mixed in the developer to deteriorate printing durability.

To attach and fix the fine particles to 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 the outer shell layer of the core particles, and the amount of the fine particles added is 5 to 20 parts by weight, preferably 8 to 15 parts by weight, based on 100 parts by weight of the core particles. If the addition amount of the fine particles is less than 5 parts by weight, the surface of the core particles will not be completely covered and the heat resistance,
If the amount is more than 20 parts by weight, fine particles that are not covered are present alone, which affects the fluidity and the like.

As the water-soluble polymerization initiator, ammonium persulfate, potassium persulfate, 2,2′-azobis (NN′-dimethyleneisobutyroamidine) hydrochloride, 2,2′-azobis (2-
Amidinopropane) hydrochloride, ferrous sulfate, hydrogen peroxide or the like is used.

Fine particles can be attached to the surface of the core particles only by mixing and stirring both the core particles and the fine particles, but the use of a water-soluble polymerization initiator makes the adhesion stronger and makes it possible to dry and classify the particles. The fine particles can be fixed so as not to be detached from the surface of the core particles. It is considered that one of the reasons is that the water-soluble initiator initiates the polymerization of unreacted monomers in both the core particles and the fine particles, and the particles are molecularly bound to each other through the polymerization reaction. .

The conditions for adhering and fixing the fine particles to the surface of the core particles, such as the amount of the water-soluble initiator added, the temperature, the reaction time, are determined by the types of monomers used to form the core particles and the fine particles, the radical polymerization initiator. In consideration of various conditions such as reaction time, 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.

Exemplarily, 0.1% to 20% by weight, preferably 1% by weight, of a core particle obtained by suspension polymerization of a water-soluble initiator.
Wt% to 10 wt%, more preferably 2 wt% to 5 wt%
Is added for about 3 to 5 hours at a temperature of 60 to 80 ° C.
This is because if the addition amount of the water-soluble initiator is less than 0.1% by weight, the fine particles will be detached from the core particles after drying, and if it is more than 20% by weight, the core particles and the fine particles will aggregate.

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

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

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

 The present invention will be described below with reference to examples.

Manufacturing method of core particles Manufacturing of core particles i: 160 g of styrene, 90 g of butyl methacrylate, 30 g of isobutyl acrylate, 3 g of lauryl mercaptan, silane coupling agent [TSL8311 (manufactured by Toshiba Silicone Co.)] 2
g, carbon black [# 2300 (manufactured by Mitsubishi Kasei)] 1
0 g and 6 g of 2,2'-azobis (isobutyronitrile) were mixed and dispersed using a homojetter (manufactured by Tokushu Kika Kogyo Co., Ltd.) to obtain a uniform mixed dispersion. Next, as a dispersion stabilizer, methylcellulose (Methocel K35LV: Dow Chemical Co., Ltd.) 4% solution 60 g, dioctyl sulfosuccinate soda (Nikkor OTP-75: Nikko Chemical Co., Ltd.) 1% solution 5
g, sodium hexametaphosphate (manufactured by Wako Pure Chemical Industries, Ltd.) 0.3 g was added to the aqueous solution obtained by dissolving 650 g of ion-exchanged water, and the above dispersion was added, and the homogenizer was used to adjust the number of revolutions to obtain an average particle size of 5 to 5. It was suspended in water to a size of 15 μm. Transfer the suspension to a four-necked flask and replace with nitrogen.
The average particle size of 11
Core particles i of μm, solid content 26%, glass transition point (Tg) 53 ° C., softening point (Tm) 80 ° C., Mw / Mn = 22 were obtained.

 The above physical properties were measured by the following methods.

 Solid content: measured using a Yamazaki-type infrared moisture meter.

 Glass transition point (Tg): measured using a differential thermobalance.

 Softening point (Tm); measured by perfect of oven.

 Number average molecular weight (Mn); measured using an osmotic pressure method.

Weight average molecular weight (Mw); measured using ultracentrifugation.

 Average particle size; measured using a Coulter counter.

Manufacture of core particles (ii) 160 g of styrene, 80 g of butyl methacrylate, 2 g of lauryl mercaptan, 1 g of silane coupling agent, pigment (red)
8g, 2,2'-azobis (2,4-dimethylvaleronitrile)
Colored core particles ii were obtained in the same manner as in the production method of core particles i except that 3 g was used. Average particle size 11μm, solid content 23%, Tg71 ℃,
The softening point was 120 ° C. and Mw / Mn = 40.

Method for producing fine particles Production of fine particles 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.
Heat to low molecular weight polypropylene (Viscor 550-
P, softening point 150 ° C., number average molecular weight (Mn) 4000: manufactured by Sanyo Kasei Co., Ltd.) 30 g of styrene dissolved in 200 g of methacrylic acid 4 g was added, and the mixture was polymerized at a stirring speed of 500 rpm for 6 hours to obtain an average particle size. 0.2 μm uniform particles a were obtained.

Production of fine particles 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, and heated to 70 ° C. while substituting with nitrogen, and low molecular weight polypropylene (Viscor-550P: manufactured by Sanyo Chemical Industry Co., Ltd.) 3
A solution prepared by dissolving 0 g of methyl methacrylate in 200 g was added, and the mixture was polymerized at a stirring speed of 200 rpm for 3 hours to give an average particle size of 0.
Uniform particles b of 4 μm were obtained.

Manufacture of fine particles c 0.2 g of ammonium persulfate was dissolved in 800 g of ion-exchanged water, transferred to a four-necked flask, replaced with nitrogen, and then heated to 70 ° C., and low molecular weight polypropylene (Viscol 550-P) 3
A solution of 0 g dissolved in 200 g of styrene was added using a dropping funnel.
The mixture was dropped for 2 hours and polymerized for 4 hours after completion of the dropping to obtain uniform particles c having an average particle diameter of 0.8 μm.

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 uniform particles b, and 2,2-azobisisobutyro Nitrile 3g and low molecular weight polypropylene (Viscor 550-
P) 280 g of methyl methacrylate containing 30 g was added dropwise over 1 hour, then kept at 70 ° C for 6 hours, and the average particle size was 1.2μ.
m uniform particles d were obtained.

Production of fine particles e In the production method of fine particles a, the stirring speed during granulation is
0.1 μm average particle size with the same composition method except 1000 rpm
To obtain uniform particles e.

Production of fine particles f to h In the production method of fine particles b, the amount of low molecular weight polypropylene (Viscol 550-P) is 40 g (fine particles f),
Uniform particles f, g and h. Having an average particle size of 0.4 μm were obtained by the same composition method except that the amounts were 5 g (fine particles g) and 1 g (fine particles h).

Production of Fine Particles i In the production method of the fine particles b, low molecular weight polyethylene (high wax: manufactured by Mitsui Petrochemical Co., Ltd., softening point is used instead of low molecular weight polypropylene (Viscol 550-P).
Other than adding 120g, number average molecular weight (Mn) 2000) 30g,
Uniform particles i having an average particle size of 0.2 μm were obtained by the same composition method.

Production of fine particles j In the production method of fine particles b, in place of low molecular weight polypropylene (Viscole 550-P), oxidized polypropylene (Viscole TS-200: manufactured by Sanyo Chemical Industry Co., Ltd., softening point)
Uniform particles j having an average particle size of 0.2 μm were obtained by the same composition method except that 30 g of 145 ° C. and a number average molecular weight (Mn) of 3500) were added.

Production of fine particles k In the production of fine particles b, instead of low molecular weight polypropylene (Viscor 550P: manufactured by Sanyo Kasei Co., Ltd.), low molecular weight polypropylene (Viscole 330P, softening point 152 ° C,
Uniform particles k of 0.4 μm were obtained by the same composition method except that the number average molecular weight (Mn) 15000: manufactured by Sanyo Chemical Industries, Ltd. was added.

Toner Production Example Production of Toner A 170 g of 20% slurry of fine particles a was added to 800 g of 26% slurry of core particles i 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 under nitrogen substitution at 70 ° C. at a stirring speed of 160 rpm for 5 hours, filtered, washed with water, dried, and had an average particle size of 10 to 20 μm.
m resin microspheres were obtained.

The softening point of the resin microspheres is 60 ° C., the angle of repose is 21 degrees,
No aggregation was observed even after standing overnight at 50 ° C. here,
The obtained particles were further classified by wind force to obtain a toner A having an average particle size of 12 μm.

Production of Toners B to L Toners B to K shown in Table 1 were obtained in the same manner as in the production of Toner A except that the fine particles a to fine particles b to k were used.

In addition, the toner L is
This is the case where the toner is composed of only core particles.

1 and 2 show photographs showing the particle structures of Toner B and Toner L, respectively. The size scale is shown in the photograph.

Manufacture of Toner M A toner M was obtained in the same manner as in the manufacture of Toner A, except that the core particles ii were used in the slurry of the core particles (i) and the fine particles b were used instead of the fine particles a.

Production of Toner N Toner N was obtained in the same manner except that the ammonium persulfate salt was removed in the production of Toner A.

A photograph showing the particle structure of Toner N is shown in FIG. The size scale is shown in the photograph.

Example of carrier production (binder type carrier) Component parts by weight Polyester resin 100 (softening point, 123 ° C; glass softening point, 65 ° C, AV23, OHV40) Inorganic magnetic powder 500 (Made by Toda Kogyo: EPT-1000) Carbon black 2 (Mitsubishi Kasei Co., Ltd .: MA # 8) The above materials were thoroughly mixed and crushed with a Henschel mixer, then the cylinder part was 180 ° C and the cylinder head part was 170 ° C.
Using the twin-screw kneader set to No. 1, the mixture was melted and kneaded. The kneaded product was cooled and then finely pulverized with a jet mill, and then classified using a classifier to obtain a magnetic carrier having an average particle diameter of 55 μm.

Evaluation of various properties The predetermined toners A to L shown in Table 1 and the above carrier were mixed at a toner / carrier ratio of 7/93, and the toner was further mixed.
100 parts by weight of colloidal silica R-972 (manufactured by Nippon Aerosil Co., Ltd.) was post-treated with 0.1 parts by weight to prepare a two-component developer, and the following evaluations were carried out.

For the developers of Examples 1, 3, 5 and Comparative Example 2 which are a combination with a −chargeable toner, a combination with EP-570Z (manufactured by Minolta Camera Co., Ltd.) and a + chargeable toner is used. Examples 2, 4 and 6 to 8 and Comparative Examples 1, 3 and 4 were evaluated using EP-470Z (manufactured by Minolta Camera). The evaluation results are shown in Table 2.

Image Quality Evaluation As described above, images were printed using the above-mentioned copying machine with various combinations of toner and carrier. As conditions, a standard chart of Dataquest Co. was copied under proper exposure conditions, and image quality was evaluated by the following method.

To evaluate the image quality, a standard chart of Data Quest Co., Ltd. was used to rank the images by comprehensively evaluating gradation, resolution, line reproducibility, and fineness of texture on the image.

Further, in this image evaluation, the glossiness was visually judged, and appropriateness and improperness were added to the evaluation criteria.

Both the image quality and the glossiness are practically usable on the rank of Δ, but ○ is preferable (Table 2).

Printing durability test Using the developers shown in Table 1, a printing durability test was performed on 10,000 sheets.

 At this time, the toner charge amount and fogging were evaluated.

Further, the degree of contamination on the surface of the photoconductor was also evaluated. It is desirable that it is practically usable with a rank or more and is ◯ (Table 2).

High temperature offset resistance EP-570Z and EP-470Z were changed in temperature of the fixing device to produce an image in the same manner as in the image quality test, and the occurrence of offset was visually determined.

The evaluation is ◎ if the fixing roller at 240 ° C does not cause offset, ○ if the fixing roller at 220 ° C does not cause offset, △ if it does not cause offset at the 200 ° C fixing roller, or △ at 200 ° C. Those in which the offset occurred were marked with x (Table 2).

Heat resistance test Put 5g of each toner in 50cc poly bottle, 24 hours in 50 ℃ environment
The product was ranked based on the cohesiveness after storage for a period of time. A value of Δ or more is practically possible, but a value of ◯ is a preferable range (Table 2).

Cleanability During the above-described image quality evaluation, visual ranking was performed according to the difference in the degree of cleaning failure on the image that occurs. ○
Indicates that cleaning failure did not occur during printing, including Δ indicates that cleaning failure did not occur initially, but cleaning occurred during printing, x
Indicates that cleaning failure occurred in the initial stage (Table 2).

 The results are shown in Table 2.

EFFECTS OF THE INVENTION The toner of the present invention has chargeability, fixability, offset prevention,
It has excellent cleaning properties and heat resistance. Especially excellent in high temperature offset prevention.

[Brief description of drawings]

 FIG. 1 is a photograph showing the particle structure of Toner B. FIG. 2 is a photograph showing the particle structure of Toner L. FIG. 3 is a photograph showing the particle structure of Toner N.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Masahiro Anno, 2-30 Azuchi-cho, Higashi-ku, Osaka City, Osaka Prefecture Minamita Camera Co., Ltd. (72) Junji Machida 2-chome, Azuchi-cho, Higashi-ku, Osaka Prefecture, Osaka No. 30 Osaka International Building Minolta Camera Co., Ltd. (56) Reference JP-A-63-18362 (JP, A) JP-A-60-186862 (JP, A) JP-A-63-249153 (JP, A) Special Kai 64-59241 (JP, A) JP 57-154253 (JP, A) JP 61-167957 (JP, A) JP 61-118758 (JP, A)

Claims (1)

[Claims] 1. A core particle formed by suspension-polymerizing a vinyl-based monomer containing at least a colorant in an aqueous solution, and soap-free emulsion-polymerizing the vinyl-based monomer in the aqueous solution to form at least an offset. A toner characterized in that fine particles containing an inhibitor are adhered and both particles are fixed by using a water-soluble polymerization initiator.