JPH0812453B2 - 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 with smaller particle size and higher fluidity are required. It is difficult to meet these demands with a pulverized and classified toner.

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 is inferior in the cleaning property that it scratches or squeezes between the photoconductor.

Further, in recent years, there has been a demand for forming a color image on an OHP sheet or a full color system by an electrophotographic method, and accordingly, a toner having a high translucency and capable of color overlapping has been demanded.

The present invention is made in view of the above problems,
An object of the present invention is to provide a toner which is excellent in chargeability, cleaning property, and fixing property by utilizing the characteristics of suspension-polymerized particles, and particularly excellent in translucency.

Means for Solving the Problems That is, according to the present invention, in a toner obtained by adhering and fixing fine particles on the surface of core particles, the softening point (Tm) of the core particles is 150.
℃ or less, number average molecular weight (Mn) 3000 ~ 15000, weight average molecular weight / number average molecular weight (Mw / Mn) is 3 or less, glass transition point (Tg) of the fine particles is 55 ℃ or more, softening point is 150 ℃
The present invention relates to an electrostatic latent image developing toner characterized by the following.

The toner for electrostatic latent image development, in which fine particles are adhered and fixed on the surface of the core particle, is prepared by suspension-polymerizing at least a vinyl monomer in an aqueous solution. Soap-free emulsion polymerization
It is obtained by attaching and fixing both particles with a water-soluble 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.

In the present invention, the core particles and the fine particles are made of materials having different physical properties in order to impart both a fixing property and a heat resistance function.

In order to impart heat resistance, the fine particles have a glass transition point (T
g) is 55 ° C or higher, preferably 58 to 150 ° C, more preferably
60 ~ 120 ℃, the softening point is 150 ℃ or less, preferably 120
It is composed of a resin having a temperature of ℃ or less.

If even one of the above physical properties of the fine particles is not satisfied,
Sufficient heat resistance cannot be obtained, or a good image cannot be obtained by projecting an image copied on OHP with an overhead projector.

The softening point (Tm) of the core particles is given to impart good translucency.
Is 150 ° C or less and the number average molecular weight (Mn) is 3000 to 1500
It is composed of a resin having a low softening point of 0, preferably 4000 to 12000. In order to further increase the light-transmitting property of the toner, the resin of the core particles is represented by the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn), and the weight average molecular weight / number average molecular weight (Mw / M
Adjust so that n) is 3 or less.

If any of the above physical properties of the core particle is not satisfied,
Fixability, toner image quality, light transmission, etc. deteriorate. When all the above-mentioned physical properties of the core particles and the fine particles are satisfied, all the objects and effects of the present invention can be achieved, and a toner having excellent translucency can be obtained, and an image copied on an OHP is an overhead projector. A good image can be obtained even when projected with. It is considered that this is because the toner of the present invention has a flat surface after fixing, which makes it difficult for light to be diffusely reflected.

If none of the above physical properties is satisfied, the light-transmitting property, the charging property, the cleaning property, and the heat resistance are poor.

The core particles are formed by, for example, a suspension polymerization method. Suspension polymerization is a method in which a polymerizable monomer is radically polymerized by adding a soluble initiator to the monomer while strongly stirring the medium that does not dissolve the monomer. Can be easily adjusted.

The fine particles 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 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.

The soap-free polymerization method can control the particle size in the range of 0.1 μm to 1 μm, and the point that particles with a sharp particle size distribution can be achieved is a point that cannot be achieved by the suspension polymerization method. Since the particle size of fine particles and the physical properties of the resin are required to adhere the particles, they are prepared by the soap-free emulsion polymerization method.

In addition to the monomer and the polymerization initiator, other desired additives such as an anti-offset agent, a charge control agent, and other desired additives may be added when preparing the core particles and the fine particles. It is effective that the offset preventing agent and the charge control agent are contained in the fine particles because the additives can exhibit their original functions.

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 charging property is
There is a problem in scattering properties and image quality.

The average size of the microparticles is 0.1 μm to 1 μm,
Preferably 0.2-0.8 μm, more preferably 0.2-0.6 μm
Use one. If 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. Further, from the viewpoint of imparting heat resistance, since the fine particle layer is thin, 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 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.

Examples of the monomer used for preparing the core particles of the present invention include vinyl monomers, for example, styrene, o-
Methyl styrene, m-methyl styrene, p-methyl styrene, p-ethyl styrene, 2,4-dimethyl styrene,
pn-butyl styrene, p-tert-butyl styrene,
p-n-hexylstyrene, p-n-octylstyrene, p-n-nonylstyrene, p-n-decylstyrene, p-n-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 monomers include, for example, ethylene unsaturated monoolefins such as ethylene, propylene, butylene, isobutylene, vinyl chloride, vinylidene chloride, vinyl bromide, vinyl fluoride such as vinyl halides, vinyl acetate, propylene acid. Vinyl, vinyl benzoate, vinyl butyrate and other vinyl esters, methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, n-octyl acrylate, dodecyl acrylate, 2-acrylic acid acrylate Ethylhexyl, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, methyl α-chloroacrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, meta Acrylic acid-propyl,
Α such as n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate and the like.
-(Meth) acrylic acid derivatives such as methylene aliphatic monocarboxylic acid esters, acrylonitrile, methacrylonitrile acrylamide, vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether, vinyl methyl ketone, vinyl hexyl ketone And vinyl ketones such as methyl isopropenyl ketone; N-vinyl compounds such as N-vinyl pyrrole, N-vinyl carbazole, N-vinyl indole, and N-vinyl pyrrolidone; and vinyl naphthalenes. 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, an organic mercaptan having at least one thiol group may be used as the polymerization regulator. Suitable organic mercaptans include methyl mercaptan, ethyl mercaptan, butyl mercaptan, octyl mercaptan, lauryl mercaptan, mercaptoethanol, mercaptopropanol, mercaptobutanol, mercaptoacetic acid, mercaptopropionic acid, thiomalic acid, benzylmercaptan, phenylmercaptan, cyclohexylmercaptan, 1 -Thioglycerol, 2,2'-
Dimercapto diethyl ether, 2,2'-dimercaptodipropyl ether, 2,2'-dimercaptodiisopropyl ether, 3,3'-dimercaptodipropyl ether, 2,2'-dimercaptodiethyl sulfide, 3,3 '-
Dimercaptodipropyl sulfide, 1,11-dimercapto-3,9-dioxa-6-thiaundecane, bis (β-mercaptoethoxy) methane, bis (β-mercaptoethylthio) methane, ethanedithio-1,2, propanedithiol -1,2, butanedithiol 1,4,3,4-dimercaptobutanol-1, trimethylolethane tri (3-mercaptopropionate), pentaerythritol tetra (3-mercaptopropionate), trimethylolpropane tritiate Includes oglycolate and pentaerythritol tetrathioglycolate.

Suitable organic mercaptans are butyl mercaptan, octyl mercaptan, lauryl mercaptan, mercaptoethanol, mercaptopropanol, mercaptobutanol, mercaptoacetic acid, mercaptopropionic acid, benzylmercaptan, phenylmercaptan, especially butylmercaptan, laurylmercaptan, mercaptoethanol, mercaptoethanol, mercaptoethanol Propanol, mercaptobutanol, mercaptoacetic acid, mercaptopropionic acid are preferred.

In addition, as the polymerization regulator, known substances such as carbon tetrachloride and α-methylstyrene dimer can be used.

A polymerization initiator may be used when the polymerizable monomer is polymerized in the present invention. For example, organic peroxides such as lauroyl peroxide, benzoyl peroxide, benzoyl peroxide oxochlor, benzoyl orthomethoxy peroxide, 2,2'-azobisisobutylnitrile, 2,2'-azobis- (2,4-
An azo initiator such as dimethylvaleronitrile can be used.

As the dispersion stabilizer in the polymerization of the polymerizable monomer, a conventional dispersion stabilizer, for example, gelatin, PVA, hydroxymethyl cellulose, methyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, sodium alginate, silica, sodium hexametaphosphate, calcium phosphate. , Barium sulfate and the like can be used, and various kinds of conventionally used surfactants and the like can be used as the dispersant.

In the suspension method, a monomer system in which a polymerization initiator, a polymerizable monomer, various additives, a dye and the like are uniformly dispersed is dispersed in a dispersion phase containing a suspension stabilizer by a homomixer. Then, the stirring speed and time were adjusted so that the droplets of the monomer had the desired toner particle size, and the dispersed solution was put into a nitrogen-substituted four-necked flask, and the temperature in the system was adjusted to 60
The temperature was raised to ℃, and the core particles were obtained by polymerizing for 24 hours at a speed at which the particles did not settle.

As the monomer used for preparing the fine particles of the present invention, the monomer used for preparing the core particles can be used.

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, p-N-staarylaminobenzyl (meth) acrylate and the like. 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-dibutylaminobenzyl (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 synthetic resin used for the fine particles may be a homopolymer using these vinyl monomers alone or a copolymer obtained by combining a plurality of vinyl monomers.

In the present invention, a polymerization initiator is used when polymerizing the polymerizable monomer. For example, a water-soluble initiator such as ammonium persulfate, potassium persulfate, and 2,2'-azobis (2-amidinopropane) can be used.

The polymerization method was as follows. Dissolve a water-soluble polymerization initiator in ion-exchanged water, transfer to a 4-neck flask, raise the temperature to a certain temperature while substituting with nitrogen, and put the polymerizable monomer and various additives into the flask. Then, the mixture is polymerized for several hours with high speed stirring to obtain fine particles.

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.

CI10316 (Naphthol Yellow S), CI11710 (Hanza Yellow 10G), CI11660 (Hanza Yellow 5G), CI11670 (Hanza Yellow 3G), CI1
1680 (Banza Yellow G), C.I11730 (Hanza Yellow G)
R), CI11735 (Hansa Yellow A), CI11740 (Hansa Yellow RN), CI12710 (Hansa Yellow R), CI127
20 (pigment yellow L), CI21090 (benzidine yellow), CI121095 (benzidine yellow G), CI2110
0 (benzidine yellow GR), CI20040 (permanent yellow NCG), CI21220 (balkan fast yellow 5),
CI21135 (Vulcan Fast Yellow R) and the like can be mentioned.

CI12055 (Stalin I), C.I.
I.12075 (Permanent Orange), CI12175 (Resor Fast Orange 3GL), CI12305 (Permanent Orange GTR), CI11725 (Hansa Yellow 3R), CI2116
5 (Vulcan Fast Orange GG), CI21110 (Benzidine Orange G), CI12120 (Permanent Red 4)
R), CI12085 (Fire Red), CI12315 (Brilliant Fast Scarlet), CI12310 (Permanent Red F2R), CI12335 (Permanent Red F4R), CI12440 (Permanent Red FRL), CI1
2460 (Permanent Red FRLL), CI12420 (Permanent Red F4RH), CI12450 (Light Fast Red Toner B), CI12490 (Permanent Carmine F)
B), CI15850 (Brilliant Carmine 6B), etc.

Examples of blue pigments include CI74100 (metal-free phthalocyanine blue), CI74160 (phthalocyanine blue), and CI74180 (fast sky blue).

These colorants may be used alone or in combination of two or more, but the thermoplastic resin 10
1 to 10 parts by weight, more preferably 2 to 0 parts by weight
It is desirable to use 5 parts by weight. That is, if the amount is more than 10 parts by weight, the fixability and translucency of the toner are deteriorated, while if it is less than 1 part by weight, a desired image density may not be obtained.

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.

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

Examples of the offset preventive agent to be contained in the core particles or the fine particles of the present invention include polyolefin waxes such as 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 (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 Kasei Co., Ltd.) and other oxidized polyethylene waxes, such as Hoechist Wachs PP230 (manufactured by Hoechst), Viscole 330-P, Viscole 550-P, Viscole 660P (manufactured by Sanyo Kasei) Examples thereof include non-oxidized polypropylene wax and oxidized polypropylene wax such as Piscol TS-200 (manufactured by Sanyo Kasei Co., Ltd.).

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, uniform dispersion with the resin component in the core particles and the fine resin particles cannot be performed, and only the wax component elutes on the toner surface, which may occur during storage or development of the toner. This is because not only unfavorable results may be brought about but also contamination of the photoreceptor such as filming may be caused. When Mn exceeds 20,000 or Tm exceeds 150 ° C., not only the compatibility with the resin deteriorates, but also the effect of incorporating a wax such as high temperature offset resistance cannot be obtained.

The wax component is particularly preferably added to the fine particles, and the addition amount to the fine resin particles is preferably 0.1 to 20% by weight, more preferably 1 to 15% by weight based on the total weight of the fine resin particles. That is, if the addition amount is less than 0.1% by weight, a sufficient offset preventing 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. This is because only the wax component is eluted on the toner surface, which may cause undesired results at the time of storing or developing the toner, and may cause contamination of the photoconductor 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 positively chargeable 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 Schwartz BB (Solvent Black 3:; Color Index 26150) Fett Schwartz HBN (CINo.26150) Priliant Spirits Schwartz TN (Farben Fabryken Bayer) Savon Schwartz X (Farberke Hoechst) Especially, alkoxy Amine amine, alkyl amide, molybdic acid chelate pigment, and the like. As the negatively chargeable charge control agent, 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,
The cleaning property and the charging property are adversely affected, and if the amount is more than 20 parts by weight, fine particles that cannot be coated adversely affect the fluidity and the charging property.

Water-soluble polymerization initiators include ammonium persulfate, potassium persulfate, 2,2'-azobis (N, N'-dimethyleneisobutyroamidine) hydrochloride, 2,2'-azobis (2-amidinopropane) hydrochloride , Ferrous sulfate, hydrogen peroxide, etc. are 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 5 to 10% 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 Core Particles A 160 g of styrene, 90 g of butyl methacrylate, 30 g of isobutyl acrylate, 3 g of α-methylstyrene dimer (Nofmer MSD: NOF CORPORATION), 3 g of silane coupling agent (TSL8311: Toshiba Silicone Co., Ltd.) 2 g , Phthalocyanine blue (CI74160) g, 2,2'-azobis (2,4-divaleronitrile) 6g homogenizer (made by Tokushu Kika Kogyo Co., Ltd.)
Was mixed and dispersed to obtain a uniform mixed dispersion. Next, as a dispersion stabilizer, methyl cellulose (Methocel K3
5LV: Dow Chemical Co., Ltd.) 4% solution 60 g, Dioctyl sulfosuccinate soda (Nikkor OTP-75: Nikko Chemical Co.) 1% solution 5 g, sodium hexametaphosphate (Wako Pure Chemical Industries, Ltd.) 0.3 g, ion-exchanged water 650 g Using a homogenizer in the aqueous solution dissolved in, the number of revolutions of the homogenizer was adjusted so that the above-mentioned uniform dispersion had an average particle size of 5 to 15 μm, and the suspension was suspended in water. The suspension was transferred to a four-necked flask and purged with nitrogen, and then polymerized at a temperature of 50 ° C. and a stirring speed of 100 rpm for 24 hours to give a solid content of 26% and a glass transition point (Tg) of 53.
C., softening point (Tm) 80.degree. C., Mn = 5000, Mw / Mn = 2.5, and an average particle size of 11 .mu.m were obtained as core particles A. In addition, the measurement of each physical property was performed by the method described below.

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

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

Softening point (Tm); measured using a perfect oven.

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

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

Particle size: Measured using a Coulter counter.

Manufacture of core particles B 160 g of styrene, 90 g of butyl methacrylate, 30 g of isobutyl acrylate, 3 g of α-methylstyrene dimer (Nofmer MSD: NOF CORPORATION), 2 g of silane coupling agent (TSL8311: manufactured by Toshiba Corp.), yellow pigment (CI121100)
4g, 2,2'-azobis (2,4-dimethylvaleronitrile)
By the same method as for the core particle A, 6 g of solid content; 27%, Tg;
℃, softening point; 81 ℃, Mn; 4000, Mw / Mn; 2.6 average particle size 10μ
m core particles B were obtained.

Manufacture of core particles C 160 g of styrene, 90 g of butyl methacrylate, 30 g of isobutyl acrylate, 3 g of α-methylstyrene dimer (Nofmer MSD: manufactured by NOF CORPORATION), 2 g of silane coupling agent (TSL8311: manufactured by Toshiba), magenta pigment (CI121200)
4g, 2,2'-azobis (2,4-dimethylvaleronitrile)
By the same method as for the core particle A, 6 g of solid content; 26%, Tg;
℃, softening point; 80 ℃, Mn; 3000, Mw / Mn; 2.6 average particle size 11μ
m core particles C were obtained.

Manufacture of core particles D 160 g of styrene, 90 g of butyl methacrylate, 30 g of isobutyl acrylate, 2 g of lauryl mercaptan, 2 g of silane coupling agent (TSL8311: manufactured by Toshiba Corporation), 4 g of phthalocyanine blue (CI74160), 2,2'-azobis (isobutyro) Nitrile) 6g by the same method as the core particle A, solid content; 25%, Tg; 53 ° C, softening point; 80 ° C, Mn; 3000, Mw / Mn; It was

Manufacture of core particle E 150 g of styrene, 40 g of butyl methacrylate, 90 g of butyl methacrylate, 2 g of silane coupling agent (TSL8311: manufactured by Toshiba Corporation), 4 g of phthalocyanine blue (CI74160),
6 g of 2,2'-azobis (isobutyronitrile) was used as the core particle A.
By the same method as above, solid content: 26%, Tg; 70 ° C, softening point: 1
Core particles E having an average particle size of 10 μm and having a Mn of 18000 and Mw / Mn of 2.7 at 60 ° C. were obtained.

 In addition, Table 1 shows various physical properties of the core particles A to E.

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 styrene, add 70g of styrene, 30g of butyl methacrylate, and 10g of methacrylic acid, and stir speed 300rp
Polymerization was performed at m for 6 hours to obtain slurry-like fine particles a having an average particle size of 0.3 μm. The glass transition point of the fine particles a is 83
℃, softening point 120 ℃, Mn; 7000, Mw / Mn; 2.5.

Production of fine particles b 2,2′-azobis (2-amidinopropane) dihydrochloride
Dissolve 0.3 g in 800 g of ion-exchanged water, transfer to a four-necked flask, warm to 70 ° C while purging with nitrogen, and add styrene 70
g, 30 g of butyl methacrylate, and 6 g of methacrylic acid were added, and the mixture was polymerized at a stirring speed of 200 rpm for 3 hours to give an average particle size of 0.
Slurry fine particles b of 4 μm were obtained. Microparticle b is T
g; 80 ° C, softening point; 90 ° C, Mn; 5000, Mw / Mn; 2.3.

Production of microparticles c 0.5 μm in the same manner as in the production of microparticles a except that the stirring speed was changed to 100 rpm in the production method of microparticles a.
Slurry fine particles c were obtained.

The fine particles c have an average particle size of 0.5 μm, Tg; 83, and a softening point of 120.
C, Mn; 7000, Mw / Mn; 2.4.

Production of fine particles d 2,2′-azobis (2-amidinopropane) dihydrochloride
Dissolve 0.2 g in 800 g of ion-exchanged water, transfer to a four-necked flask, and warm to 70 ° C while purging with nitrogen, and add styrene 60
g, 35 g of butyl methacrylate, and stirring speed 130 rpm
After 1 hour of polymerization, 30 g of styrene, 15 g of butyl methacrylate and 4 g of diethyl methacrylate were stirred with a dropping funnel for 1 hour, and after completion of the dropping, polymerization was carried out for 4 hours to obtain slurry-like fine particles d. Fine particles b have an average particle size of 0.2μ
m, Tg; 70 ° C., softening point; 130 ° C., Mn; 6000, Mw / Mn; 2.3.

Production of fine particles e 2,2′-azobis (2-amidinopropane) dihydrochloride
Dissolve 0.3 g in 800 g of ion-exchanged water, transfer to a four-necked flask, warm to 70 ° C while purging with nitrogen, add 30 g of polypropylene dissolved in 200 g of methyl methacrylate, and stir at 200 rpm for 3 hours. Polymerized slurry-like fine particles e were obtained. The fine particles e have an average particle size of 0.4 μm, T
g; 105 ° C., softening point; 180 ° C., Mn; 50000, Mw / Mn; 2.5.

Production of fine particles f 0.4 g of ammonium persulfate was dissolved in 800 g of ion-exchanged water, transferred to a four-necked flask, replaced with nitrogen, and heated to 75 ° C., and 60 g of methyl methacrylate, 85 g of isobutyl acrylate and 5 g of methacrylic acid were added. Then, the mixture was polymerized at a stirring speed of 200 rpm for 3 hours to obtain slurry-like fine particles f.
Fine particles f have an average particle diameter of 0.2 μm, Tg; 53 ° C., softening point; 65
C, Mn; 5000, Mw / Mn; 2.3.

Production of fine particles g 20% of fine particles b in a four-necked flask replaced with nitrogen.
Add 760g of deionized water to 200g of the slurry containing it, 3000rpm
With stirring, 3 g of 2,2'-azobisisobutyronitrile, 30 g of styrene, and 70 g of butyl methacrylate were added dropwise over 1 hour, and the mixture was kept at 70 ° C for 6 hours to obtain slurry-like fine particles g. Fine particles g have an average particle diameter of 1.2 μm, Tg; 4
It was 1 degreeC, the softening point; 48 degreeC, Mn; 5000, Mw / Mn; 2.3.

Production of fine particles h In the production method of the fine particles a, the stirring speed during granulation is 10
Uniform particles k having an average particle diameter of 0.1 μm were obtained by the same composition method except that the speed was set to 00 rpm.

The fine particles k have an average particle diameter of 0.1 μm, Tg of 63 ° C. and a softening point of 13
It was 0 degreeC, Mn; 7000, Mn / Mw; 2.5.

 In addition, Table 2 shows various physical properties of the fine particles a to g.

Toner Production Example Production of Toner A 65 g of 20% slurry of fine particles a was added to 300 g of 26% slurry of core particles A, dispersed in 1000 g of ion-exchanged water, and 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, washed with filtered water, dried, and classified to have an average particle size of 1
1.5 μm resin microspheres were obtained.

Toner B Toner B having an average particle size of 11.5 μm was obtained in the same manner as in the production of Toner 1, except that 300 g of 27% slurry of core particle B and 20% slurry of fine particles a were used.

Toner C Toner C having an average particle size of 11.5 μm was obtained in the same manner as in the production of Toner 1, except that 20% slurry of fine particles a was used for 300 g of 26% slurry of core particles C.

Toner D Toner D having an average particle size of 12.0 μm was obtained in the same manner as in the production of Toner 1, except that 300 g of 25% slurry of core particles A and 65 g of 20% slurry of fine particles b were used.

Toner E Toner E having an average particle size of 12.0 μm was obtained in the same manner as in the production of Toner 1, except that 20% slurry of fine particles c was used for 300 g of 26% slurry of core particles A.

FIG. 1 shows a photograph showing the particle structure of Toner E. The size scale is shown in the photograph.

Toner F Toner F having an average particle size of 11.0 μm was obtained in the same manner as in the production of Toner 1, except that 20% slurry of fine particles d was used for 300 g of 26% slurry of core particles A.

Toner G (Comparative) Toner G having an average particle size of 11.5 μm was obtained in the same manner as in the production of Toner 1 except that 65 g of 20% slurry of fine particles a was used for 300 g of 25% slurry of core particles D.

Toner H (Comparative) A toner H having an average particle size of 11.5 μm was obtained in the same manner as in the production of Toner 1, except that the 26% slurry of the core particles E and the 65% 20% slurry of the fine particles a were used.

Toner I (Comparative) A toner I having an average particle size of 12.0 μm was obtained in the same manner as in the production of the toner 1, except that the 26% slurry of the core particles A and the 65% 20% slurry of the fine particles e were used.

Toner J (Comparative) A toner J having an average particle size of 11 μm was obtained in the same manner as in the production of Toner 1 except that 65 g of 20% slurry of fine particles f was used for 300 g of 26% slurry of core particles A.

Toner K (Comparative) A toner K having an average particle size of 13.0 μm was obtained in the same manner as in the production of Toner 1, except that 300 g of 26% slurry of core particles A and 65 g of 20% slurry of fine particles g were used.

Toner L (Comparative) Core particles A were washed with water, dried, and classified to obtain toner L having an average particle size of 11.0 μm.

FIG. 2 shows a photograph showing the particle structure of Toner F. The size scale is shown in the photograph.

Toner M (Comparative) A toner M having an average particle size of 10.4 μm was obtained in the same manner as in the production of the toner A except that the 26% slurry of the core particle A was used and the 65% of the 20% slurry of the fine particles k was used.

Toner N (Comparative) Toner N was obtained in the same manner as in Toner A except that the ammonium persulfate was removed.

FIG. 3 shows a photograph showing the particle structure of Toner N. The size scale is shown in the photograph.

In Table 3, combinations of core particles and fine particles in the preparation of toners A to N are summarized, and the toner polarity is also shown.

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 (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 toner shown in Table 4 and the above carrier were mixed in a ratio of toner / carrier = 7/93, and colloidal silica R-972 (manufactured by Nippon Aerosil Co., Ltd.); 0.1 part by weight per 100 parts by weight of the toner. After processing was carried out in parts, a two-component developer was prepared and evaluated as described below.

In addition, EP-570Z (manufactured by Minolta Camera Co., Ltd.) is used for a developer combined with −chargeable toner, and EP-470Z (manufactured by Minolta Camera Co., Ltd.) is used for a developer combined with + chargeable toner. It was used for evaluation. The evaluation results are shown in Table 4.

Image Quality Evaluation As described above, images were printed using the above copying machine with various combinations of toner and carrier. As conditions, a standard chart of Dataquest Co. was copied under appropriate 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 standard.

Both the image quality and the glossiness can be used in terms of Δ rank, but ○ is preferable (Table 4).

Printing endurance test Using the developers shown in Table 4, a printing endurance test was performed on 10,000 sheets. It is practically usable with a rank or more, but is preferably ◯.

Translucency Translucency visually evaluates the vividness of colors in a projected image when projected on an OHP projector, and the symbols in the table indicate the following.

◯: The color is vivid and can be favorably used as a translucent color toner.

Δ: Colored color is recognized but turbidity is present.

X: The color is turbid, or appears black on an OHP projector, and cannot be practically used as a translucent color toner.

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 4).

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 no cleaning failure occurred, including during printing durability, Δ indicates that cleaning failure did not occur initially, but cleaning failure occurred during printing durability,
× indicates that cleaning failure occurred in the initial stage (Table 4).

Charging property 2 g of toner and 28 g of carrier, which have been surface-treated (post-treatment with 0.1 part by weight of colloidal silica R-972 (manufactured by Nippon Aerosil Co., Ltd.) per 100 parts by weight of toner), are put in a 50 cc plastic bottle and placed on a rotary mount. Rotate at 1200 rpm, 3 minutes, 10 minutes, 3
The charge amount after stirring for 0 minutes was measured, and the rise of the toner charge amount was examined (Table 4).

Fixability The initial image was copied on paper and OHP sheet to evaluate the fixability. The fixing strength is ◎ if the image is not disturbed even after rubbing 20 times or more with a sand eraser, ○ from 15 times to 20
Five to fifteen times was marked as Δ, and less was marked as × (Table 4).

In Comparative Examples 4 and 5, the developer was agglomerated in the developing device during the printing durability test, so the test was stopped midway.

Effect of the Invention The toner of the present invention is excellent in charging property, cleaning property and heat resistance. In particular, it has excellent translucency and transparency.

[Brief description of drawings]

 FIG. 1 is a photograph showing the particle structure of Toner E. 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) Junji Machida, 2-30 Azuchi-cho, Higashi-ku, Osaka-shi, Osaka Prefecture Minami Camera Co., Ltd., Osaka International Building (72) Masahiro Anno 2-chome, Azuchi-cho, Higashi-ku, Osaka-shi, Osaka No. 30 Osaka International Building Minolta Camera Co., Ltd. (56) Reference JP-A-59-3445 (JP, A) JP-A-63-212944 (JP, A) JP-A-58-205162 (JP, A) Special Kai 61-118758 (JP, A) JP 62-237462 (JP, A) JP 1-142557 (JP, A) JP 58-198049 (JP, A) JP 58-142346 ( JP, A) JP 59-214860 (JP, A)

Claims (1)

[Claims] 1. A toner comprising fine particles adhered and fixed on the surface of core particles, wherein the softening point (Tm) of the core particles is 150 ° C. or lower,
Number average molecular weight (Mn) is 3000 to 15,000, weight average molecular weight /
A toner having a number average molecular weight (Mw / Mn) of 3 or less, a glass transition point (Tg) of fine particles of 55 ° C. or higher, and a softening point of 150 ° C. or lower.