JPH01257856A - Toner for developing electrostatic latent image - Google Patents

Abstract

PURPOSE:To obtain a toner for developing an electrostatic latent image having superior electrostatic chargeability, cleanability and fixability by adhering and fixing fine particles having specified characteristics on the surfaces of core particles contg. a colorant and having specified characteristics in a wet state. CONSTITUTION:Fine particles are adhered and fixed on the surfaces of core particles contg. the colorant in the wet state to obtain the toner for developing the electrostatic latent image. The core particles are formed by suspending and granulating at least polyester resin. The fine particles are formed by emulsion-polymerizing vinyl resin with no soap and the average particle size is regulated to 0.2-1.0mum. The fine particles are firmly fixed on the surfaces of the core particles and the toner has a rugged structure formed by coating the surfaces of the core particles with the fine particles retaining the original spherical shape. The toner has superior electrostatic chargeability, cleanability and fixability.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a toner for developing electrostatic latent images.

Conventional technology and its problems Conventionally, toner for developing electrostatic latent images is produced by melt-kneading thermoplastic resin, colorant, and other additives, and crushing and classifying the mixture to obtain a desired particle size distribution. Manufactured.

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

Today, as copying machines become more widespread, there is an increasing demand for high-quality images and high-speed development. It is difficult to meet these demands with pulverized and classified toner.

Therefore, in place of the pulverized and classified toner, a suspension polymerization toner has been proposed which allows the particle size to be reduced and whose particles are formed into spherical shapes.

are doing.

However, when the toner is triboelectrically charged, the probability of contact with the carrier is small due to its shape, resulting in poor triboelectrification.Also, when cleaning the remaining toner on the photoconductor, the toner is small and spherical, so the toner cannot be used with the cleaning blade. It easily slips between the photoreceptor and has poor cleaning performance.

Further, from the viewpoint of high-speed development and energy saving, toners that can be fixed at low temperatures are desired, but such toners are made of low softening point resins, have no heat resistance, and cause problems such as toner aggregation.

In addition to the above-mentioned problems, another characteristic required of toners is resistance to vinyl chloride. Generally, when copies are stored in a vinyl chloride sort, etc., there is a problem that the toner is eroded by the plasticizer in the vinyl chloride sheet and fuses to the sheet. This was noticeable in toners whose main component was resin. Therefore, it has been known to use a polyester resin as the main component of a PVC-resistant toner.

However, polyester resin has polar groups (-CooH group,
-○H group), etc., the environmental resistance was poor, and there was a problem in stabilizing the charging property especially at high humidity.

Problems to be Solved by the Invention The present invention has been made in consideration of the above-mentioned problems, and provides a toner that takes advantage of the characteristics of spherical particles and also has excellent charging properties, cleaning properties, and fixing properties, especially low-temperature fixing properties. The purpose is to provide.

A further object of the present invention is to provide a toner with excellent vinyl chloride resistance and environmental resistance.

As a means to solve the problem, the present invention provides a toner for developing electrostatic latent images in which fine particles are adhered and fixed on the surface of core particles containing a colorant in a wet process, in which the core particles are made of at least a polyester resin. The fine particles are obtained by soap-free emulsion polymerization of vinyl resin and have an average particle size of 0.2 to 0.2 mm.
The present invention relates to a toner for developing an electrostatic latent image characterized in that the particle size is 10 μm.

An electrostatic latent image developing toner in which fine particles are side-fixed on the surface of a core particle is obtained by dissolving at least a polyester resin in a solvent, suspending and granulating it in an aqueous solution, and removing the solvent. It is obtained by soap-free emulsion polymerization of system monomers in an aqueous solution, and by adhering and fixing rain particles using a water-soluble initiator.

Alternatively, an electrostatic latent image developing toner in which fine particles are adhered and fixed to the surface of core particles is prepared by dissolving at least a polyester resin in a solvent, suspending it in an aqueous solution, and granulating it, and in the process of removing the solvent, forming a soap-free emulsion. It is obtained by adding vinyl polymer microparticles obtained by polymerization, making them adhere to the surface of the core particle, swelling the microparticles when the solvent is removed, and fixing them by completely removing the solvent.

The toner of the present invention has a structure in which microparticles are firmly attached and fixed on the surface of a core particle, and unevenness is imparted thereto. The unevenness is formed by the fine particles covering the surface of the core particle 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 charging properties are obtained, and the cleaning properties of the toner are improved.

According to the present invention, the core particles are formed of polyester resin in order to impart vinyl chloride resistance. Further, in order to improve the environmental resistance of the polyester resin, the microparticles are formed from a vinyl resin.

Furthermore, in the present invention, in order to impart both fixing properties and heat resistance functions, the core particles and the microparticles are made of materials having the physical properties shown below.

In order to impart heat resistance, the microparticles are heated to the glass transition point (Tg).
) is 55 to 150°C, preferably 60 to 120°C. If it is composed of a material with a Tg lower than 55°C, the heat resistance will be poor and toner aggregation will be a problem.
If the toner has a Tg higher than 150° C., the fixing performance will be poor.

In order to provide good fixing properties, the core particles have a softening point (Tm).
is 70 to 180°C, and the number average molecular weight (M n ) is 3000 to 20000, preferably 4000 to 1200.
0 polyester resin.

If all of the above-mentioned physical properties of the core particles and fine particles are satisfied, problems arise in cleaning properties, vinyl chloride resistance, environmental resistance, fixing properties, or heat resistance.

Furthermore, in order to improve the fixing properties of the toner, the number average molecular weight (Mn) of the resin of the core particle is lower than the weight average molecular weight (Mw).
The molecular weight distribution (Mw/Mn) expressed as the ratio to 10
-70, preferably 10-50.

The core particles according to the invention are produced by a suspension method. Suspension granulation is a method in which polyester resin is uniformly dissolved and/or shaken and dispersed in a low boiling point solvent, the solvent and a medium that does not dissolve the polyester resin are granulated with strong stirring, and the solvent is removed by heating. The size of particles generated can be easily adjusted under stirring conditions.

The size of the core particles is adjusted to have an average particle diameter of 20 μm or less, preferably 2 to 15 μm. If it is thicker than 20 μm, the image quality will be rough and the charging property will also be poor.

The fine J/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 the emulsifier is removed from the emulsion polymerization system, and initiator radicals generated in the aqueous phase bind monomers that are slightly dissolved in the aqueous phase, which eventually become insolubilized and form particle nuclei. . Particles produced by this polymerization method generally have a larger particle size than those produced by emulsion polymerization, with an average particle size of 02 to 1 μm and a narrow particle size distribution.

In the present invention, since fine particles having an average particle diameter of 02 to 1 μm are used as the fine particles to be attached to the surface of the core particles, it is preferable to adjust them by soap-free emulsion polymerization.

The fine particles used have an average particle diameter of 02 μm to 1 μm, preferably 0.2 to 08 μm. If the average particle diameter of the microparticles is smaller than 0+μm, it is difficult to provide unevenness on the surface of the core particles for the purpose of the present invention. In addition, from the viewpoint of imparting heat resistance, since the thickness of the fine particle layer is thin, the purpose cannot be sufficiently achieved.

When the average particle diameter of the microparticles is larger than 1 μm, it becomes difficult to uniformly adhere the microparticles to the surface of the core particle, the surface coverage decreases, and the toner cleanability, durability, etc. are not sufficiently improved. First, when the purpose is to impart heat resistance,
It becomes more susceptible to the influence of core particles. Furthermore, due to the size of the microparticles, it is difficult to firmly adhere and fix the particles to the surface of the core particle.

In the toner for developing electrostatic latent images 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 polyhydric carboxylic acid or its anhydride.

As the diol, polyoxypropylene (2゜2)
-2,2-bis(4-hydroxyphenyl)propane,
Polyoxyethylene (2,0)-2.

2-bis(4-hydroxyphenyl)propane, polyoxy7propylene(31,:q)-2,2-bis(4
-hydroxyphenyl)furopane, polyoxypropylene (2,0)-polyoxyethylene, (2°0)-2,
2-bis(4-hydroquinphenyl)propane, polyoxypropylene(6)-2,2-bis(4-hydroxyphenyl)propane, polyoxystyrene(3)-bis(2',6-dipromo-4-hydroxy phenyl)methane, polyoxybutylene(2,,5)-bis(4-hydroxyphenyl)ketone, polyoxyethylene(3)-
Bis(4-hydroxyphenyl)ether, polyoxystyrene (2:.

8)-Bis(24,+5-diglome-4-hydroxyphenyl)thioether, polyoxyethylene (2,.

5)-Bis(2-,,6-dipromo4-hydroxyphenyl)sulfo7,polyoxypropylene (3)-2゜2-bis(2-?,6-difluoro4-hydroxyphenyl)propane, polyoxy Propylene (2I2)-
Examples include 2,2-bis(4-hydroxy-2'.6-dichlorophenyl)propane.

Also, as polyhydric carboxylic acids, fumaric acid, maleic acid,
Examples include phthalic acid, maleic anhydride, inphthalic acid, terephthalic acid, phthalic anhydride, trimellitic acid, trimellitic anhydride, alkylcono-phosphate, alkenylcono-phosphate, and the like. Alkyl or alkenylco...
Examples of the acid include n-tothycenylsuccinic acid, indodecenylsuccinic acid, n-dodecylsuccinic acid, indodecylsuccinic acid, n-octylsuccinic acid, n-butylsuccinic acid, and the like.

Further, preferred tricarboxylic acids include trimellitic acid (1,2,4-benzenetricarboxylic acid), toluentriecarboxylic acid, and/chlorhexanetricarboxylic acid, and examples of the tetracarboxylic acid include 4-neobentrizonyl-] ,,2,6.7-hebutanetetracarboxylic acid,4-neopentyl-1,2゜6.7-hepteno(4)
-tetracarboxylic acid, 3-methyl-4-hebutenol 1
．． 2,5.6-hexatetracarboxylic acid, 3-methyl-
3-heptyl-5-methyl-1,2,6,7-heptene(4)-tetracarboxylic acid, 3-nonyl-4-methylisonyl-1,2°5.6-hexanetetracarboxylic acid, 3
-Denrydenyl-1,2,5,6-hexanetetracarboxylic acid, 3-nonyl-1,2,6,7-hepteno (4)
-tetracarboxylic acid, 3-decenyl-1,2,5,6-
Hexanetetracarboxylic acid, 3-butyl-3-ethylenyl-1,2,5,6-hexanetetracarboxylic acid, 3-
Methyl-4-butyrisonyl-1,2,6,7-hebutanetetracarboxylic acid, 3-methyl-4-butyl-1,2,
6,7-heptene(4)-tetracarboxylic acid, 3-methyl-5-octyl-1,2,6,7-heptene(4)-
Examples include tetracarboxylic acid and the like.

In addition, polymerization is generally obtained by a known method.

Examples of the low boiling point solvent for dissolving 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, ciglopylether, benzene, toluene, quincylene, etc. can be used, and they may be used alone or in combination.

In the electrostatic latent image developing toner of the present invention, the vinyl resin used for the fine particles covering the core particle is not particularly limited, and may be a homopolymer or copolymer made of various vinyl monomers as shown below. Although these polymer blends can be used, styrene polymers, styrene-(meth)acrylic copolymers, etc. are preferably used.

Examples of vinyl monomers include styrene, 0-methylstyrene, m-methylstyrene, P-methylstyrene, P-ethylstyrene, 7.2.4-dimethylstyrene,
P-n-butylstyrene, p-tert-butylstyrene, p-n-hequinrustyrene, p-n-octylstyrene, p-n-nonylstyrene, p-n-decylstyrene, p-n-totenrustyrene, P-methoxy Styrene, P-methkinstyrene, P-phenylstyrene, P-
Examples include styrene and derivatives thereof such as chloroethyl 7.3.4-dichlorostyrene, among which styrene is most preferred. Examples of other vinyl monomers include vinyl acetate, vinyl propionate, vinyl benzoate,
Vinyl esters such as vinyl butyrate, methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, n-octyl acrylate, dodenyl 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, -]3-propyl methacrylate, n methacrylate -Ethylene aliphatic monocarboxylic acid esters such as octyl, dodefur methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, acrylonitrile, methacrylonitrile, acrylamide (meth)acrylic acid derivatives such as 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-vinyl compounds such as vinylcarbasol, N-vinylindole, N-vinylpyrrolide 7, and vinylnaphrines.

As the coloring agent contained in the core particles in the electrostatic latent image developing toner of the present invention, various organic and inorganic pigments and dyes of various colors as shown below can be used.

-14= That is, examples of black pigments include carbon blank, 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, Nefrun yellow, and naphthol yellow S1.
Basser Yellow G, Basser Yellow], OG1 Benzidine Yellow G, Benzidine Yellow GR1 Quinolino Yellow Lake, Permanent Yellow NCG, Tartrazine Lake, etc.

Orange pigments include red yellow lead, molybdenum orange, permanent orange GTR, pyrazolone orange, Harukat orange, and industhrene brilliant orange RK.
, Benonjin Orange G1 Indus Thread Brilliant Orange GK, etc.

Red pigments include Benokara, cadmium red, red lead, mercury sulfide, cadmium, and Permanentret 4R-1.
l) Solelet, Pyrazolone Red, Uonochinoglenod, Calcium Salt, Lake Red D, Brilliant Carmine 6B, Eon Lake, Rogue Mil-Ki B, Alizarin Lake, Brilliant Carmine 3B and the like.

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

Examples of blue pigments include navy blue, cobalt blue, alkali blue lake, Victoria blue lake, phthalo/anine blue, thermometal phthalo/anine blue, partially chlorinated phthalon animble, fast sky blue, and industhrene blue BC.

Examples of green pigments include chrome green, chromium oxide, pigment green B1 micalite green pigment, and final yellow green G.

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

Extender pigments include palite powder, barium carbonate, clay, sled, white carbon, Merck, and alumina white.

Various dyes such as basic, acidic, acidic, and direct dyes include Nigrono, methylene blue, rose bengal,
Colors include quinolino yellow and ultramarine blue.

These colorants can be used alone or in combination.

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

In the present invention, the core particles and/or the 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 microparticles 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 polyolefin waxes include, for example:
Hoechst Wax PE520, Hoechs [
WaxPE130, l-1oechsL Wax PE
l 9Q (manufactured by Hoechst), Mitsui Hiwax 20
0, Mitsui Noh Iwasokusu 210, Mitsui Hiwax 21
0M1 Mitsui Hiwax 220, Mitsui Iwanox 2
20 M (manufactured by Mitsui Petrochemical Industries), Sunwax 1
31-P, Sunwax], 51. -I'.

Non-oxidized polyethylene wax such as Sunwax 161-P (manufactured by Sanyo Chemical Industries, Ltd.), I-(oecb
s LWax PED i21, l-1oechst
Wax PED 153, (-10echsLWax
PED521, Hoechst Wax P4D 52
2, Ceridus 3620, Ceridus L
VP], 30, Cer 1dus tVP5905
, Ccridus [VP g615A, Ceridu
oxidized polyethylene wax such as st TM9610 F (manufactured by Hoechst), Mitsui Hiwax 420M (manufactured by Mitsui Petrochemical Industries, Ltd.), Sunwax E-300, Sunwax J Otsu-250P (manufactured by Sanyo Chemical Industries, Ltd.), I(oechist Wachs PP 230
(manufactured by Hoechst) Viscole 330-P, Viscole 5
Examples include non-oxidized polypropylene wax such as 50-Pl Viscol 660-P (manufactured by Sanyo Chemical Industries, Ltd.), and oxidized polypropylene wax such as Viscol TS-200 (manufactured by Sanyo Chemical Industries, Ltd.).

The wax used in the present invention has a number average molecular weight (
Mn) of 1,000 to 20,000 and a softening point (T m ) of 80 to 150°C are used. If Mn is 1000 or less or Tm is 80°C or less, the resin component in the core particles and minute resin particles cannot be uniformly dispersed, and only the wax component is eluted onto the toner surface, causing problems during toner storage or development. This may not only cause undesirable results, but also may cause contamination of the photoreceptor such as filming. Also, Mn is 20
If Tm exceeds 000 or Tm exceeds 1.50° C., not only will the compatibility with the resin deteriorate, but the effect of including wax in high temperature offset resistance methods etc. will not be obtained.

The wax component is particularly preferably added to the fine particles, and the amount added to the fine resin particles is 01 to 20% by weight, more preferably 1 to 15% by weight of the total weight of the fine resin particles. preferable. In other words, if the amount added is less than 0.1% by weight, a sufficient offset prevention effect cannot be exhibited, while if the amount added exceeds 20% by weight, uniform dispersion with the resin component in the micro resin particles cannot be achieved. This is because not only the wax component alone may be eluted onto the toner surface, resulting in unfavorable results during storage or development of the toner, but also contamination of the photoreceptor such as filming.

Note that even if the amount of the wax component added is close to 20% by weight of the fine resin particles, the amount of the wax component relative to the entire toner particles is still small, and the image quality may be excessive due to the high content of the wax component. There are no problems with gloss or the like.

Polyolefin waxes include other waxes, such as synthetic hydrocarbon waxes such as Finnoya-Tropsch wax; vegetable waxes such as cantelli wax, carnauba wax, rice wax, water wax, and jojoba oil; paraffin wax, Petroleum waxes such as microcrystan wax and petrilactam; Modified waxes such as Monkwanox derivatives, paraffin wax derivatives, and microcrystan wax derivatives; Soricone oils such as dimethyl silicone oil and phenylmethyl silicone oil; Other various fatty acids,
It may be used together with synthetic waxes such as acid amides, acid imides, esters, and ketones, 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 charge control agent or a negatively chargeable charge control agent can be used, depending on the purpose of the toner.

Examples of positively charged charge control agents include ■ Nigrosine Base EX (manufactured by Orient Chemical Co., Ltd.) ■ Quaternary ammonium salt P-51 (manufactured by Orient Chemical Co., Ltd.) ■ Nigrosine Bontron N-Ql (manufactured by Orient Chemical Co., Ltd.) (manufactured by Co., Ltd.) ■ Sudan Chief Funyubartu BB (Solvent Black 3: ; Co1orInde
x 26150) ■ Phenoto 7 Yubarno HBN (c, I, NO, 26150) ■ Brilliant Spirinotschno Kurz TN (Methylpen Fabriken Kuiyasha ff) ■ Sabon Yubarz X (manufactured by Methylwerke Hoechst) In particular, alkoxy amine, alkylamidomolybdic acid chelate pigment, etc.;
26150) Oil Black BY (manufactured by Orient Chemical Co., Ltd.) ■ Bontron S-22 (Made by Orient Chemical Co., Ltd.) ■ Salicylic acid metal complex E-81 (manufactured by Orient Chemical Co., Ltd.) ■ Thioindigo pigment ■ Sulfonyl of copper phthalocyanine Amino derivative ■ Spiron black T R I-I (Hodogaya Chemical)
(manufactured by Orient Chemical Co., Ltd.) ■ Bontron 534 (manufactured by Orient Chemical Co., Ltd.) ■ Nigelossia SO (manufactured by Orient Chemical Co., Ltd.) ■ Ceres Schwarz (R)G (Methylpen Fapriken) (Earl) [Phase] Chromogen Schwarz ETOO (C0I, No. 1
4645) ■ Azo Oil Black (R) (manufactured by Nanyonal Aniline Co., Ltd.).

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, but the amount of charge control agent added to the microparticles constituting the outer shell layer is 100 parts by weight of the synthetic resin forming the microparticles. 0.001 to 10 parts by weight,
Preferably it is 0.01 to 5 parts by weight. That is, if the amount added is less than 0,001 parts by weight, the amount of charge control agent present on the surface of the toner particles is small, resulting in insufficient charge of the toner, while if it exceeds 10 parts by weight, the outer shell layer This is because there is a risk that the charge control agent may peel off and become spent on the surface of the carrier, or be mixed into the developer, resulting in deterioration of printing durability.

In order to adhere and fix the microparticles to the surface of the core particles, a predetermined amount of the core particles and microparticles 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 40 parts by weight, preferably 10 to 30 parts by weight, based on 100 parts by weight of the core particles. If the amount of fine particles added is less than 5 parts by weight, the surface of the core particles cannot be completely coated, which will have a negative effect on heat resistance, cleaning performance, and chargeability. Small particles that cannot be used have a negative effect on fluidity and charging properties.

Examples of water-soluble polymerization initiators include ammonium persulfate, potassium persulfate, 2,2'-azobis(N,N'-dimethyleneisobutyramidine) hydrochloride, 2.2'-77'bis(
(2-amidinopropane) hydrochloride, ferrous sulfate, hydrogen peroxide, etc. are used.

The fine particles can be attached to the surface of the core particle simply by mixing and stirring the core particles and rain particles of the fine particles, but using a water-soluble polymerization initiator makes the attachment even stronger and prevents the particles from drying or classifying. It is possible to fix the microparticles so that they do not separate from the surface of the core particle. One reason for this is thought to be that the water-soluble initiator initiates polymerization of unreacted monomers in the microparticles, and the two particles are molecularly bonded through the polymerization reaction.

The conditions for adhering and fixing the microparticles to the core particle surface, such as the amount of water-soluble initiator added, temperature, reaction time, etc., depend on the type of monomer used to form the core particle and microparticles, and the radical polymerization initiator. Taking into account various conditions such as reaction time, reaction time, etc., conditions may be appropriately selected so that the fine particles can be firmly adhered and fixed to such an extent that they are not adversely affected by detachment of the fine particles from the core particle during actual use.

-25~ The toner of the present invention can be mixed with a suitable carrier to form a two-component developer. Known carriers can be used, and the toner is usually blended in an amount 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. Silica as a fluidizing agent,
Examples include aluminum oxide, titanium oxide, silica/aluminum oxide mixture, silica/titanium oxide mixture, and the like.

Further, in order to improve cleaning performance, a metal soap such as zinc stearate may be externally added.

The present invention will be explained below using examples.

Polyester resin (NE-382 manufactured by Kao Corporation) 100g
was dispersed in a mixed solution of methylene chloride/toluene (8/2) to obtain a uniform mixed dispersion. Next, as a dispersion stabilizer, 60 g of a 4% solution of methylcellulose (35LV in Methocel, manufactured by Dow Chemical Company), 5 g of a 1% solution of dioctyl sulfosuccinate soda (Ckkol 0TP-75, manufactured by Nikko Chemical Company), and sodium hexametaphosphate (manufactured by Wako Pure In an aqueous solution of 05g (manufactured by Yakusha) dissolved in 1000g of ion-exchanged water, use a homojetter to suspend the above homogeneous dispersion in water by adjusting the rotational speed of the homojetter so that the average particle size is 3 to 12μm. Ta. Transfer the suspension to a four-loaf flask, and The mixed solvent of methylene chloride/toluene was removed in 5 hours at a temperature of 70° C. and a stirring speed of 1100 rpm to obtain spherical core particles A with a solid content of 10% and an average particle size of 8 μm.

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 Example A except that 6 g of phthalocyanine pigment was used instead of carbon black.

, Production of core particle C Polyester resin (Vylon 200 Toyobo) 100g
was dissolved in 400 g of methylene chloride, and 10 g of carbon black MA #8 (manufactured by Mitsubishi Kasei ■) was used in the same manner as in Production A to obtain spherical core particles C with a solid content of 10% and an average particle size of 8 μm.

Dissolve 04 g of ammonium persulfate in 800 g of ion-exchanged water, transfer to a four-loaf flask, and while substituting with nitrogen,
Humidify at 75°C, add 200 g of methyl methacrylate dissolved in 8 g of methacrylic acid, and stir at 300 r.
Polymerization was carried out at pm for 6 hours to obtain uniform particles a with an average particle diameter of 2 μm. The glass transition point of microparticles a was 108°C.

Production of microparticles 2.2 03 g of 1-azobis(2-amidinopropane) dihydrochloride was dissolved in 800 g of ion-exchanged water, transferred to a four-ring flask, heated to 70°C while purging with nitrogen, and dissolved in methyl methacrylate. ) Pour the dissolved 200g into
Polymerization was carried out for 3 hours at a stirring speed of 20 rpm to obtain uniform particles with an average particle diameter of 4 μm.

The glass transition point of the microparticles was 105°C.

Production of microparticles C 02g of ammonium persulfate was dissolved in 800g of ion-exchanged water, transferred to a four-hole flask, and replaced with nitrogen.
The mixture was heated to 70° C., 200 g of styrene was added dropwise through a dropping funnel over 2 hours, and polymerization was carried out for 4 hours after the addition was completed to obtain uniform particles C with an average particle diameter of 08 μm. The glass transition point of the microparticles C was 105°C.

Production of microparticles d In a four-bottle flask purged with nitrogen, 200g of slurry containing 205X of 04μm microparticles was added with 77g of ion-exchanged water.
Add 60 g of methyl methacrylate-1 containing 3 g of 2,2-azobisisobutyronitrile while stirring at 300 rpm.
After dropping -280g over 1 hour,
After holding for a period of time, uniform particles d with an average particle size of 12 μm were obtained. The glass transition point of the microparticles d was 105°C.

Production of microparticles e In the method for producing microparticles a, the stirring speed during production i is set to 1.
The average particle size was 0 using the same composition method except that it was 100 Orp.
Uniform particles e of 1 μm were obtained. The glass transition point of the microparticles e was 108°C.

Add 2 of microparticles 3 to 800g of 10% slurry of core particle A.
1'70g of 0% slurry was added, dispersed in 1000g of ion exchange water, and 5g of ammonium persulfate was added.

The dispersion was transferred to a four-round flask and heated to 70°C under nitrogen atmosphere.
The mixture was reacted for 5 hours at a stirring speed of 16 Q rpm, filtered, washed with water, and dried to obtain resin microspheres with an average particle size of 10 to 20 μm.

Here, the obtained particles were further subjected to air classification to obtain Toner 1 having an average particle size of 10 μm.

Preparation of Toners 2 to 8 Toners 2 to 7 were obtained in the same manner as Toner 1 except that the core particles and fine particles were changed as shown in Table 1.

Toner 8 was made of only core particles A without adhering microparticles.

Table 1 Ingredients Part by weight Polyester resin 100 (softening point, 123°C; glass softening point, 65°C, AV23.0HV40) Inorganic magnetic powder 500 (manufactured by Toda Kogyo Co., Ltd.: EPT-1000) Carbon Bra Tsuk
2 (manufactured by Mitsubishi Kasei Corporation: MA$8) The above materials were thoroughly mixed and pulverized using a Henschel mixer,
Next, the cylinder part is heated to 180°C, and the cylinder part is heated to 170°C.
The mixture was melted and kneaded using an extrusion kneader set at ℃. After cooling, the kneaded material was finely pulverized using a die-nod mill, and then classified using a classifier to obtain a magnetic carrier having an average particle size of 55 μm.

Evaluation of toner characteristics Predetermined toners 1 to 8 shown in Table 1 and the above carrier were mixed at a ratio of toner/carrier = 7/93, and further, colloidal silica R-972 (manufactured by Nippon Aerosil Co., Ltd.) was added to 100 parts by weight of the toner. A two-component developer was prepared by post-processing with 0.01 parts by weight, and the evaluation described below was performed.

Note that EP-570Z (manufactured by Minolta Camera Co., Ltd.) is used for the developer used in combination with -chargeable toner, and El''-470 is used for the developer used in combination with +chargeable toner.
Evaluation was performed using Z (manufactured by Minolta Camera Co., Ltd.).

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

At this time, the toner charge amount and cleaning performance were evaluated, and the results are shown in Table 2. The cleaning performance was visually ranked based on the difference in the degree of cleaning failure on the image. ○ indicates that no cleaning defects occurred during printing, △ indicates that cleaning defects did not occur during initial printing, but cleaning defects occurred during printing, and X indicates that cleaning defects occurred in the early stages. shows.

Toner stored in seven environmental resistance test chambers (temperature 18 to 25 degrees Celsius, humidity 30 to 60%) and toner stored in a high temperature and high humidity environment (temperature 35 degrees Celsius, humidity 30 to 60%).
The charge amount of the toner was measured at room temperature after being stored for 24 hours at a humidity of 85%, and the comparative results are shown in Table 3. In the table, ◯ indicates that there was almost no change in the charge amount due to the environment, and × indicates that the charge amount changed significantly (4 to 8 μc/g) and toner scattering was observed.

Heat Resistance Test 5g of each toner was placed in a 5Qcc polybottle and stored in an environment of 50°C for 24 hours, after which the toner was judged by its a magnetism and ranked. A value of ∆ or more is practically possible, but a value of ◯ is a preferable range (Table 3).

PVC Resistance Test The PVC resistance test was carried out by overlapping a vinyl chloride resin sheet manufactured by Mitsui Toatsu Chemical Co., Ltd. containing 50% by weight of dioctyl phthalate with the image surface of copy paper, and heating it in an oven at 35°C for 1 h/ca.
After applying the same pressure and leaving it for 24 days, take it out and peel it off, and observe the state of toner transfer to the sheet. If there is no change in the copied image and no toner has transferred at all, it will be marked as ○.
A sheet in which toner transfer was observed was evaluated as x.

(Margin below) Table 3 Effects of the Invention The toner of the present invention has charging properties, cleaning properties, PVC resistance,
Excellent environmental resistance, fixing properties, and heat resistance.

Applicant: Minolta Camera Co., Ltd.

Claims (1)

[Claims] 1. In a toner for developing an electrostatic latent image formed by adhering and fixing microparticles on the surface of a core particle containing a colorant in a wet process, the core particles are formed by suspending and granulating at least a polyester resin, and the microparticles A toner for developing electrostatic latent images, wherein the particles are obtained by soap-free emulsion polymerization of a vinyl resin and have an average particle size of 0.2 to 1.0 μm.