JPH04177365A - Toner for developing electrostatic latent image - Google Patents

Abstract

PURPOSE:To make improvements in developability and image density as well as to make it have sufficient transferability by providing a nonisolable fine grain locally on an isolative toner grain surface, and letting a toner grain act as its isolability in a static manner. CONSTITUTION:A nonisolable fine grain stuck fast to an isolative toner grain surface is locally provided on a toner surface, and this toner grain acts as its isolability in a static manner. This nonisolable fine rain receives an electric load from a latent image, and this part shows an electric potential approximating to the latent image after the toner grain is stuck onto the latent image, whereby a new toner grain is further stuck onto the toner grain, therefore plural layers of toners are stuck onto the latent image, thereby making image density improvable in consequence. On the other hand, at time of transfer, the nonisolable fine grain stuck onto the toner surface is merely provided locally and discontinuous, so that at time of electrostatic transferring, such a fear that the electric charge will run past on the toner surface is not caused, thus good transferability is secured. With this constitution, sufficient image density is securable and simultaneously both of good developability and transferability are securable too.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a toner for developing electrostatic latent images. Specifically, the present invention relates to an electrostatic latent image developing toner for developing electrostatic latent images in electrophotography, electrostatic recording, and electrostatic printing.

(Prior Art) Development of electrostatic latent images in electrophotography, electrostatic recording, and electrostatic printing involves electrically applying colored charged particles called toner to the electrostatic latent image formed on a photoreceptor. This is done by attaching it to the surface and visualizing it.

Known methods for imparting an electric charge to the toner used in the development of such electrostatic latent images include triboelectric charging, electrostatic induction, and charge injection. The most common method is to In other words, in the two-component development method, an insulating non-magnetic toner is used as the toner and is charged by mixing and diffusing with a substance generally called a carrier, while in the one-component development method using an insulating toner, the toner is Electric charge is applied by contact with a sleeve, a toner regulating blade, or the like.

Incidentally, in recent years, there has been a demand for higher image quality in the area of electrophotographic copying machines and printers, and in accordance with this demand, efforts are being made to reduce the particle size of toner. It is known that reducing the particle size of toner has a great effect on improving image resolution, gradation, line reproducibility, and the like. On the other hand, however, when the particle size of the toner is reduced, a problem arises in that the density after transfer is insufficient if only one layer of toner is deposited on the surface of the photoreceptor during maintenance. To obtain sufficient density, multiple layers of toner must be deposited on the photoreceptor surface.

In order to adhere multiple layers of toner on the photoconductor surface in this way, even for toner that uses triboelectric charging during development, the electrical conductivity of the toner is increased, and the surface potential of the photoconductor is increased on the toner adhered to the photoconductor. It is thought that a method of communicating this is effective.

However, when considering the transferability of toner from a photoreceptor to a transfer material such as paper, there is a problem that toner with increased electrical conductivity and conductivity does not transmit the transfer electric field sufficiently, resulting in a significant decrease in transfer efficiency. It was something that would happen.

By the way, for example, JP-A-63-40167, JP-A-63-50863, JP-A-63-240556,
JP-A No. 2003-100023 discloses a toner formed by partially adhering an insulating substance to the surface of a conductive toner. These documents all relate to conductive magnetic toner, and address the problem of poor transfer efficiency due to the conductivity of toner in simultaneous methods, which are one of the one-component development methods that perform development by charge injection. This is attempted to be improved by attaching an insulating substance to the toner surface and utilizing the electrical charge of this insulating substance during transfer.

However, even if an insulating substance is attached to the toner surface in this way, since the toner core particles exhibit conductivity,
Even during transfer, the charge from the transfer charger etc.
The transfer efficiency did not reach a satisfactory level because it passed through the core particle and did not function properly.

Furthermore, JP-A-63-257178 discloses a toner characterized in that an insulating part and a conductive part are provided on the toner surface, and a p-type or n'J1 semiconductor is used as the conductive material. Similar to the above, an insulating part is provided on the surface of the toner to utilize the electrical charges in this part during transfer, and a conductive part is made of a semiconductor to impart polarity to its conductivity. During development, a current with a polarity that follows the semiconductor polarity is passed between the toner particles to inject charge, while during transfer, the discharge charge from the transfer charger has the opposite polarity to the semiconductor polarity, so these conductors are reduced by contact with the transfer material. It has been shown that even if the charge from the transfer charger is neutralized, this charge of the opposite polarity is further injected into the toner, preventing the toner from being charged to the same polarity as the charge from the transfer charger and improving transfer efficiency. There is. Furthermore, that-
Examples include a structure in which p-type or n-type semiconductor fine powder is embedded in the surface of a general insulating toner and conductive parts are individually present.

However, since this toner is used in the simultaneous method like the toner shown in the above-mentioned literature, the magnetic spikes made of this magnetic toner need to exhibit conductivity during development, and the toner chains In order for the magnetic spike to be conductive, each particle must statically exhibit conductivity, and a conductive portion must be formed over a considerable area of the toner surface. Therefore, when trying to apply a toner having such a structure to a system in which development is performed by imparting a charge by frictional charging, it was not possible to obtain a sufficient amount of charge.

(Problems to be Solved by the Invention) Therefore, an object of the present invention is to provide a toner for developing an electrostatic latent image that solves the above-mentioned problems. Another object of the present invention is to provide a toner for developing electrostatic latent images that has improved developability and image density and has sufficient transferability. A further object of the present invention is to provide a toner for developing electrostatic latent images that is suitable for reducing the particle size in order to obtain high quality images.

(Problem to be Solved by the Invention) The above-mentioned problem is that in a toner in which non-insulating fine particles are fixed to the surface of insulating toner particles, the non-insulating fine particles are locally present on the toner surface, and as toner particles. This is achieved by a toner for developing electrostatic latent images that is characterized by statically insulating behavior.

(Function) When toner particles that have been triboelectrically charged, electrostatically or magnetically restrained, and transported by carrier particles or a developing sleeve collide with the latent image surface on the photoreceptor during development,
-Behaves like a flash free particle and performs movements such as rolling or rotating on the surface of the photoreceptor. After that, the toner particles electrostatically adhere to the latent image surface, or during the free particle movement before that, the non-insulating fine particles locally fixed to the toner surface receive an electric charge from the latent image surface, and this region After the toner particles are deposited on the latent image, they exhibit a potential close to that of the latent image surface.

In this way, a region having a potential close to that of the latent image surface is formed on the surface of the toner particles adhering to the latent image, so that more toner particles adhere to this toner particle, resulting in the latent image. Multiple layers of toner can be deposited on top to increase image density.

On the other hand, during transfer, the toner is sandwiched between the photoreceptor and a transfer material such as paper and cannot freely rotate or otherwise move. In the toner for developing electrostatic latent images of the present invention, the non-insulating fine particles fixed to the toner surface exist only locally, and these locally existing portions are discontinuous over the entire toner surface. Therefore, during electrostatic transfer when the toner is in a static state as described above, charges do not flow on the toner surface, and transferability is ensured.

Hereinafter, the present invention will be explained in more detail based on embodiments.

The toner for developing electrostatic latent images of the present invention has non-insulating fine particles fixed to the surface of the toner core particle, and the core particle is made of at least a colorant and a synthetic resin, and as necessary. Optionally, it is possible to have other toner property improvers such as anti-offset agents, charge control agents, etc.

In the toner for developing electrostatic latent images of the present invention, the core particles are not particularly limited as long as they can be obtained by a conventionally known method for manufacturing toner particles, such as by a pulverization method, or It may be a wet granulation method that involves a polymerization process such as a suspension polymerization method or an emulsion polymerization method, or a wet granulation method that does not involve a polymerization process such as a suspension method or a spray drying method.

More specifically, when using the pulverization method, core particles can be obtained by mixing and kneading a coloring agent and the like with a thermoplastic resin, and then pulverizing and classifying the mixture. Note that it is also possible to spheroidize the particles thus obtained by subjecting them to heat treatment or the like.

When using the suspension polymerization method, a polymer composition containing a polymerizable monomer capable of forming a resin component as a binder, a polymerization initiator, a colorant, and other additives as described below is mixed in a non-solvent medium. Pelletization is performed by suspending and polymerizing.

In the case of emulsion polymerization, it is preferable to use a method known as a seed polymerization method, since intra-membrane emulsion polymerization provides a good particle size distribution but only extremely small particles. That is, a part of the polymerizable monomer and a polymerization initiator are added to an aqueous medium or an aqueous medium to which an emulsifier has been added, stirred and emulsified, and then the remainder of the polymerizable monomer is gradually added dropwise to obtain fine particles. Polymerization is carried out using these particles as seeds in polymerizable monomer droplets containing a colorant and other additives.

In addition, wet granulation methods involving polymerization processes include soap-free emulsion polymerization method, microcapsule method (interfacial polymerization method,
(n-situ polymerization method, etc.), non-aqueous dispersion polymerization method, etc. are known.

In the case of a suspension method, a coloring agent and other additives are blended with a resin component as a binder as described below and melted, and this is suspended in a non-solvent medium to perform granulation.

In the case of spray drying, the synthetic resin component is dissolved in a solvent together with a coloring agent, and then spray dried to form granules.

However, the method for producing the core particles used in the toner for developing electrostatic latent images of the present invention is of course not limited to the method exemplified above.

In the toner for developing electrostatic latent images of the present invention, the synthetic resin constituting the core particles is not particularly limited as long as it is commonly used as a binder in ordinary toners, such as styrene-based resins, thermoplastic resins such as (meth)acrylic resins, olefin resins, polyester resins, amide resins, carbonate resins, polyethers, polysulfones, etc., or thermoplastic resins such as epoxy resins, urea resins, urethane resins, etc. Thermosetting resins, copolymers and polymer blends thereof, and the like are used. The binder resin used in the present invention includes not only those in a complete polymer state such as thermoplastic resins, but also those in an oligomer or prepolymer state such as thermosetting resins. It also includes polymers containing prepolymers, crosslinking agents, etc.

Recently, there has been a demand for technology that can copy at even higher speeds, and the toner used in such high-speed systems needs to be able to fix the toner to transfer paper in a short time, and to separate it from the fixing roller. need to be improved. Therefore, when trying to obtain toner used in such high-speed systems, styrene monomers,
It is desirable to use homopolymers or copolymers synthesized from (meth)acrylic monomers, (meth)acrylate monomers, or polyester resins, and their molecular weights include number average molecular weight (Mn) and weight average molecular weight ( The relationship between M w ) and Z average molecular weight (Mz) is 1,000≦7,000.40≦M w /
M n≦70.200≦M z / M n≦500
, and the number average molecule ffi (Mn) is further 2,
000≦Mn≦7.000 is preferably used. When used as an oil-less fixing toner, the glass transition temperature is 55 to 80°C and the softening point is 80°C.
It is desirable that the temperature is 150° C. and that 5 to 20% by weight of a gelling component is further contained.

In addition, when trying to obtain a translucent color toner for OHP use or full color use, the binder resin must have vinyl chloride resistance, translucency as a translucent color toner, and adhesion to the OHP sheet. From this point of view, it is desirable to use a polyester resin, and in this case, the glass transition temperature is 55 to 70°C, the softening point is 80 to 150°C,
The number average molecular weight (Mn) is 2.000~
15,000 and a molecular weight distribution (M w / M n ) of 3 or less. Furthermore, as a binder resin when attempting to obtain a translucent color toner, a linear urethane-modified polyester (C) obtained by reacting a linear polyester resin (A) with a diisocyanate (B) is also suitably used. . The linear urethane-modified polyester referred to here is composed of dicarboxylic acid and diol, and has a number average molecular weight of 2.000 to 15.000,
A linear urethane-modified polyester resin obtained by reacting 0.3 to 0.95 mol of diisocyanate (B) per 1 mol of a linear polyester resin with an oxidation rate of 5 or less and whose terminal group is essentially a hydroxyl group, and The main component of the resin (C) is one having a glass transition temperature of 40 to 80°C and an oxidation rate of 5 or less. Furthermore, polymers that are modified by copolymerizing linear polyester with acrylic or aminoacrylic monomers, etc. by methods such as grafting or block polymerization, and that have the same glass transition temperature, softening point, and molecular weight characteristics as above, are also suitable. used for.

Here, specific monomers constituting the binder resin used in the present invention include the following. That is, as vinyl monomers, for example, styrene, 0-methylstyrene, m-methylstyrene, p-methylstyrene, etc.
-Methylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, p-n-butylstyrene, p-tert
-butylstyrene, p-n-hexylstyrene, p-n
-octylstyrene, p-n-nonylstyrene, p-n
-decylstyrene, p-n-dodecylstyrene, p-methoxystyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, 3゜4-dichlorostyrene and other styrenes and their derivatives, among which Styrene is most preferred. Examples of other vinyl monomers include ethylenically unsaturated monoolefins such as ethylene, propylene, butylene, and isobutylene, vinyl halides such as vinyl chloride, vinylidene chloride, vinyl bromide, and vinyl fluoride, vinyl acetate, and propion. Vinyl esters such as vinyl acid, vinyl benzoate, vinyl butyrate, methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, n-octyl acrylate, dodecyl acrylate, acrylic acid 2 -ethylhexyl, 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, dimethylamino methacrylate α-methylene aliphatic monocarboxylic acid esters such as ethyl, diethylaminoethyl methacrylate, (meth)acrylic acid derivatives such as acrylonitrile, methacrylonitrile, acrylamide, etc., vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether, etc. Vinyl ethers, vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, methyl isopropenyl ketone, N-vinylpyrrole, N-
Examples include N-vinyl compounds such as vinylcarbazole, N-vinylindole, and N-vinylpyrrolidone, and vinylnaphthalenes. The binder resin may be a homopolymer using only one of these vinyl monomers, or a copolymer using a combination of a plurality of these vinyl monomers.

As a monomer for obtaining a polyester resin, polyol components include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1°3-butanediol, 2,3-butanediol, 1,5-bentanediol, 1,6-hexanediol, neopentyl glycol, 2-ethyl 1
゜3-Hexanediol, 2,2.4-)-dimethyl-
1,3-bentanediol, 1,4-bis(2-hydroxymethyl)cyclohexane, 2,2-bis(4-hydroxypropoxyphenyl)propane, bisphenol A1 hydrogenated bisphenol A1 polyoxyethylenated bisphenol A, etc. Polybasic acid components include maleic acid, fumaric acid, mesaconic acid, citraconic acid, itaconic acid, glutaconic acid, 1,2,4-benzenetricarboxylic acid, 1. 2. Unsaturated carboxylic acids such as 5-benzenetricarboxylic acid, phthalic acid, terephthalic acid, isophthalic acid, succinic acid, adipic acid, malonic acid, sebacic acid, 1,2.4-cyclohexanetricarboxylic acid, 1,2.5-cyclohexane Tricarboxylic acid, 1,2
．． 4-butanetricarboxylic acid, 1,3-dicarboxylic acid
2-Methyl-2-methylcarboxypropane, tetra(
Examples include saturated carboxylic acids such as methylcarboxy)methane, and acid anhydrides thereof and esters with lower alcohols. Specifically, for example,
Maleic anhydride, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, endomethylenetetrahydrophthalic anhydride, tetrachlorophthalic anhydride, tetrabromophthalic anhydride, dimethyl terephthalate, and the like. In addition, the polyester resin used in the present invention is not limited to one obtained by polymerizing a combination of one type each of the polyol component and polybasic acid component as described above, but may be one obtained by polymerizing a combination of two or more types of each. In particular, the polybasic acid component is often a combination of an unsaturated carboxylic acid and a saturated carboxylic acid, and (1) a combination of a polycarboxylic acid and a polycarboxylic acid anhydride.

Monomers for obtaining amide resins include caprolactam, tribasic acids include terephthalic acid, isophthalic acid, adipic acid, maleic acid, succinic acid, cepatic acid, thioglycolic acid, and diamines include caprolactam. Examples include ethylenediamine, diaminoethyl ether, 1,4-diaminobenzene, and 1,4-diaminobutane.

Monomers for obtaining urethane resin include p-phenylene diisocyanate, p-phenylene diisocyanate, and p-phenylene diisocyanate.
Examples of the glycols include xylene diisocyanate and 1°4-tetramethylene diisocyanate, and examples of the glycols include ethylene glycol, diethylene glycol, propylene glycol, and polyethylene glycol.

Examples of monomers forming urea resins include diisocyanates such as p-phenylene diisocyanate, p-xylene diisocyanate, and 1,4-tetramethylene diisocyanate; examples of diamines include ethylenediamine, diaminoethyl ether, and diisocyanate. ，
Examples include 4-diaminobenzene and 1,4-diaminobutane.

As monomers for obtaining epoxy resins, examples of amines include ethylamine, butylamine, ethylenediamine, 1,4-diaminobenzene, 1,4-diaminobutane, monoethanolamine, etc.; Examples include glycidyl ether, ethylene glycol dicrycidyl ether, bisphenol A diglycidyl ether, and hydroquinone diglycidyl ether.

Furthermore, the binder resin contained in the toner particles as described above may be a polymer of a monomer component having a nitrogen-containing polar functional group or fluorine as shown below, or a polymer containing the above monomer and a monomer component as shown below. A copolymer with a monomer component having a nitrogen-containing polar functional group or fluorine, or a polymer obtained by polymerizing the above-mentioned monomers with a monomer component having a nitrogen-containing polar functional group or fluorine as shown below. It is also possible to use polymer blends with. When a synthetic resin into which a polar group is introduced in this way is used, this synthetic resin itself acts as a charge control function, so that the charge control function contained in the toner particles or attached to the surface of the toner particles, as described below, can be used. It becomes possible to impart desired charging properties with a smaller amount of the agent.

Nitrogen-containing polar functional groups are effective for positive charge control, and monomers having nitrogen-containing polar functional groups include the following general formula (1) % formula % () (wherein R1 is hydrogen or a methyl group, R2 and R3 is 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.

Some specific examples of the amino(meth)acrylic monomer include, for example, N.

N-dimethylaminomethyl (meth)acrylate, N,
N-diethylaminomethyl (meth)acrylate, N,
N-dimethylaminoethyl (meth)acrylate, N,
N-dimethylaminopropyl (meth)acrylate, p
-N,N-dimethylaminophenyl (meth)acrylate, p-N-laurylaminophenyl (meth)acrylate, p-N-stearylaminophenyl (meth)acrylate, p-N,N-dimethylaminobenzyl (meth)acrylate , N,N-dimethylaminoethyl (meth)acrylamide, N,N-dimethylaminopropyl (
Examples include meth)acrylamide and the like.

Fluorine atoms are effective for controlling negative charge, and there are no particular restrictions on the fluorine-containing monomer, but examples include 2゜2.2-)lifluoroethyl acrylate, 2゜2.3.3-tetrafluoropropyl acrylate, 2゜2.3.3-tetrafluoropropyl acrylate, ,2,3,3.4,
4,5.5-octafluoroamyl acrylate, IH
, IH, 2H.

, 2H-hebutadecafluorodecyl acrylate and other fluoroalkyl (meth)acrylates are preferred examples. In addition, trifluorochloroethylene, vinylidene fluoride, trifluoroethylene, tetrafluoroethylene, trofluoropropylene, hexafluoropropene, hexafluoropropylene, and the like can be used.

Further, the colorant contained in the toner for developing electrostatic latent images of the present invention is not particularly limited, but for example,
Various organic and inorganic pigments and dyes of various colors can be used as shown below.

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

Yellow pigments include yellow lead, zinc yellow, cadmium yellow, yellow iron oxide, mineral fast yellow, nickel titanium yellow, navel yellow, naphthol yellow S1 Hansa Yellow G1 Hansai Elo-1061 Benzidine Yellow G1 Benzidine Yellow GR, quinoline yellow lake, permanent There are yellow NCG, tartrazine lake, etc.

Orange pigments include red yellow lead, molybdenum orange, permanent orange GTR, pyrazolone orange, palkan orange, and industhrene brilliant orange RK.
, Benzidine Orange G1 Intaslen Brilliant Orange GK, etc.

Red pigments include red pigment, cadmium red, red lead, mercury sulfide, cadmium, permanent red 4R, lithol red, pyrazolone red, watching red, calcium salt, lake red C, lake red D1 brilliant carmine 6B1 eosin lake, rhodamine lake. B1 Alisarin Lake, Brilliant Carmine 3B, etc.

Examples of violet pigments include manganese violet, fast violet B1 methyl violet lake, and the like.

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

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

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

Extender pigments include pallite powder, barium carbonate, clay, silica, white carbon, talc, and alumina white.

In addition, various dyes such as basic, acidic, dispersed, and direct dyes include nigrosine, methylene blue, rose bengal,
They include quinoline yellow and ultramarine blue.

These colorants can be used alone or in combination, but it is usually desirable to use 1 to 20 parts by weight, more preferably 2 to 10 parts by weight, based on 100 parts by weight of the binder resin. That is, if the amount is more than 20 parts by weight, the fixing properties of the toner will deteriorate, while if it is less than 1 part by weight, there is a risk that the desired image density may not be obtained.

Alternatively, in an embodiment in which the electrostatic latent image developing toner of the present invention is a translucent color toner, the colorant contained in the toner may include various pigments and dyes of various colors as shown below. Available for use.

Examples of yellow pigments include C01,10316 (Naphthol Yellow S), C0I, 11710 (Hansa Yellow 1)
0G) C, 1,11660 (Hansa Yellow 5G),
C01,11670 (Hansa Yellow 3G), C,1
,11680 (Hansa Yellow G) ,C,1,117
30 (Hansa Yellow GR), C, 1, 11735 (
Hansa Yellow A), C, 1, 11740 (Hansa Yellow RN), C0I, 12710 (Hansa Yellow R
), C01,12720 (Pigment Yellow L), C
91,21090 (benzidine yellow), C, 1°1
21095 (Benzidine Yellow G), C, I.

21100 (Benzidine Yellow GR), C, I.

20040 (Permanent Yellow NCG), C.

1.21220 (Palcan Fast Yellow 5), C
, 1,21135 (Palcan Fast Yellow R).

Red pigments include C,1,12055 (Stalin I), C,1,12075 (Permanent Orange)
), C,1,12175 (Resol Fast Orange 3GL), C,1,12305 (Permanent Orange GTR), C,1,11725 (Hansa Yellow 3
R), C,1,21165 (Palcan Fast Orange GG), C,I.

21110 (Benzidine Orange G), C, 1°12
120 (Permanent Red 4R), C, I.

1270 (Rose Red), C,1,12085 (Fire Red), C,1,12315 (Brilliant Fast Scarlet), C,1,12310 (Permanent Red F2R), C8I.

12335 (Permanent Red F4R), C.

1.12440 (Permanent Red FRL), C0
1,12460 (Permanent Red FRLL), C
, l, 12420 (Permanent Red F4RH)
, C,1,12450 (Light Fast Red Toner B), C,1,12490 (Permanent E-Min FB), and C01,15850 (Brilliant Carmine 6B).

Examples of blue pigments include C, 1,74100 (metal-free phthalocyanine blue), C, 1,74160 (phthalocyanine blue), and C, 1,74180 (fast sky blue).

These colorants can be used alone or in combination, but usually 1 to 10 parts by weight, more preferably 2 to 5 parts by weight, per 100 parts by weight of the binder resin. desirable. That is, if the amount is more than 10 parts by weight, the fixing properties and light transmittance of the toner will be reduced, while if it is less than 1 part by weight, the desired image density may not be obtained.

Specifically, various waxes, particularly polyolefin waxes such as low molecular weight polypropylene, polyethylene, or oxidized polypropylene and polyethylene, are preferably used as the anti-offset agent used to improve the fixing properties of the toner.

The charge control agent is not particularly limited, and various organic or inorganic agents can be used as long as they can impart positive or negative charge through triboelectric charging.

As a positive charge control agent, for example, nigrosine base EX
(Orient Chemical Industry Co., Ltd.), Quaternary ammonium salt P
-51 (manufactured by Orient Chemical Industry ■), Nigrosine Bontron N-01 (manufactured by Orient Chemical Industry ■), Sudan Chief Schwarz BB (Solvent Black 3: C
o1or Index 26150), Fetschwarz HBN (C11, NO, 26150), Brilliant Spirits Schwarz TN (manufactured by Farpen Fabriken Bayer), Zabon Schwarz Examples include molybdate chelate pigments, and examples of negative charge control agents include Oil Black (Color Index 26150), Oil Black BY (manufactured by Orient Chemical Industry ■), and Bontron S-22 (manufactured by Orient Chemical Industry ■). , salicylic acid metal complex E-81 (Orient Chemical Industry Co., Ltd.), thioindigo pigment, sulfonylamine derivative of copper phthalocyanine, Spiron Black TRH (manufactured by Hodogaya Chemical Industry Co., Ltd.)
, Bontron 5-34 (manufactured by Orient Chemical Industry ■),
Nigrosine So (manufactured by Orient Kagaku Kogyo ■), Ceres Schwarz (R) G (manufactured by 7 Alpen Fabriken Bayer), Chromogen Schwarz ETOO (C, 1
, NO., 14645), Azo Oil Black (R) (manufactured by National Ken Aniline Co., Ltd.), and the like.

In the toner for developing electrostatic latent images of the present invention, the non-insulating substance fixed as fine particles to the surface of the core particle having the above-mentioned structure may also be used to prevent the toner particles from rolling or rotating on the latent image on the photoreceptor. There is no particular limitation on the material as long as it can receive charge from the latent image surface during the movement and have a potential close to that of the latent image surface, but preferably a volume resistivity of 1010 Ω.
A material having a resistance of less than am, more preferably less than 10 Ω·cm is desirable. Specifically, examples include metals or metal alloy powders such as aluminum, zinc, iron, copper, nickel, silver, palladium, or stainless steel, resins coated with metals such as aluminum coats, nickel coats, and silver coats. Examples include fine particles, carbon powder such as acetylene black and Ketschen black, and metal compounds such as tin oxide and titanium oxide. Magnetic powders such as magnetite, γ-hematite, and various ferrites may also be used.

Further, as for the size of such non-insulating fine particles, it is desired that the average particle diameter is 1 μm or less, more preferably 0.5 μm or less. In other words, when a non-insulating substance is added to the toner surface, the charging characteristics of the toner are greatly influenced by the amount of the non-insulating substance exposed on the toner surface. When using relatively large particles, the number of non-linear fine particles fixed per toner particle is small, and even if the number of fixed particles changes only slightly, the weight of fixed non-insulating substances between toner particles will vary. This is because the charging characteristics of the toner vary.

Therefore, in the toner for developing electrostatic latent images of the present invention,
The above non-insulating fine particles externally added to the core particle are locally fixed to the surface of the core particle. That is, as mentioned above, when the triboelectrically charged toner is attached to the latent image surface on the photoconductor, the instantaneous toner particles behave like free particles and perform movements such as rolling or rotation, so that the surface of the core particle is When non-insulating fine particles are fixed, the non-insulating fine particles receive an electric charge from the latent image surface, and after adhering to the latent image surface, they exhibit a charge similar to that of the latent image surface, and another toner particle is placed on this toner particle. However, if such non-insulating fine particles are uniformly adhered to the entire surface of the core particle, the toner will exhibit conductivity and will be difficult to transfer during transfer. This is because the transfer electric field is not sufficiently transmitted, making transfer by Coulomb force difficult.

As described above, in the toner for developing electrostatic latent images of the present invention,
Because the non-insulating fine particles are fixed to the surface of the core particle or because the non-insulating fine particles are locally arranged, the toner particles statically behave as insulating.

Furthermore, the non-insulating fine particles that adhere to the surface of the core particle are minute, but because they are locally present in this way, for example when the fine particles are dispersed (by long-term stirring) It is unlikely that many non-insulating fine particles will be embedded in the toner particles and the amount of non-insulating material functioning as a nail will be reduced, and stable functionality can be exhibited over a long period of time.

In addition, as for the local distribution state of such non-insulating fine particles, in particular, the area where the fixation density (D) of non-insulating fine particles on the core particle surface is 50% or less of the average D is the area on the core particle surface. It is desirable to meet the condition that the area where D is 20% or more of the total, more preferably 30% or less with respect to the average D is present at 30% or more of the entire core particle surface.

Furthermore, the amount of the non-insulating fine particles added depends on the type of the non-insulating fine particles, and is 0.1 to 10 parts by weight, preferably 0.5 to 10 parts by weight, based on 100 parts by weight of the core particles.
5 parts by weight is desired. That is, core particles 10
If the amount of non-insulating fine particles added exceeds 10 parts by weight relative to 0 parts by weight, even if the non-insulating fine particles are locally distributed, the toner particles will statically exhibit conductivity, resulting in poor transfer. On the other hand, if the amount added is less than 0.1 part by weight, a sufficient portion of the same potential as the latent image surface will not be formed on the toner particle surface during development. This is because multiple layers of toner cannot adhere to the latent image surface, so there is a high possibility that the image density will not be sufficient.

Furthermore, in the toner for developing electrostatic latent images of the present invention, in addition to the non-insulating fine particles as described above, other additives such as a fluidizing agent are externally added as fine particles to the surface of the core particle. It is also possible to attach or fix the
Such other additive fine particles are insulating and are desirably added uniformly to the surface of the core particle. In other words, if such other additive fine particles are insulating, not only will the original function of the additive fine particles be exhibited, but the non-insulating fine particles will locally form on the surface of the toner particles. The insulation properties of the parts (parts where non-insulating particulates are sparsely present) other than the part where non-insulating particulates are present (parts where non-insulating particulates are sparsely present) are made more reliable, and the presence of non-insulating particulates is This is because the dense portions can be made significantly independent from each other, and the insulation properties of the toner particles as a whole can be ensured. Insulating fine particles that can be suitably used in the present invention include silica, aluminum oxide, titanium oxide, magnesium septate, etc. as a fluidizing agent, and in addition, emulsion polymerization method, soap-free emulsion polymerization method, and non-silica. Styrene-based, (meth)acrylic-based, polyolefin-based, granulated by wet polymerization methods such as water dispersion polymerization method, gas phase method, etc.
There are various organic fine particles such as benzoguanamine, melamine, silicone, and polytetrafluoroethylene. Furthermore, it is desirable that the particle size of such other additive fine particles be 115 or less of the core particle in order to make the adhesion amount uniform in each toner particle.

The toner for developing electrostatic latent images of the present invention has non-insulating fine particles locally fixed to the surface of the core particle as described above. For example, a device that applies a wet coating method such as Disper Coat (manufactured by Nissin Engineering Co., Ltd.) or Coat Mizer (manufactured by Freund Sangyo Co., Ltd.) is used to make the material adhere to the surface of the material. powder,
This can be accomplished by applying a liquid immersion method in which the particles are brought into contact with the liquid medium by colliding with a wall surface on which the liquid medium is flowing. That is, non-insulating fine particles are dissolved or dispersed in the liquid medium, the flow rate of the liquid medium is reduced, a part of the powder (core particle) surface is wetted by the above treatment, and then this liquid medium is dried and removed. This causes non-insulating fine particles to remain attached to the area.

Alternatively, the core particles obtained as described above may be aggregated to an appropriate size while maintaining the shape of the sides to some extent without completely melting or dissolving the core particles.
The aggregate thus obtained is treated with a surface modification device conventionally used to attach and/or fix various additive particles to the surface of the toner particles, such as a hybridization system (Nara Kikai Seisakusho Co., Ltd.). manufactured by),
Equipment that applies a high-speed air impact method such as the Cosmos System (manufactured by Kawasaki Heavy Industries, Ltd.); equipment that applies a dry mechanochemical method such as the Mechano Fusion System (manufactured by Hosokawa Micron) and Mechano Mill (manufactured by Kaida Seiko);
For example, non-insulating fine particles can be uniformly coated on the surface using a device that applies a modification method in hot air flow such as the Suffusing System (manufactured by Nippon Pneumatic Kogyo Co., Ltd.) or a device that applies a wet coating method such as the one described above. If non-insulating fine particles are adhered tightly to the surface, and then the aggregates formed by such non-insulating fine particles are uniformly and closely adhered to the surface are broken down to form toner particles, the particles will have some particles on the outer surface of the aggregates. The non-insulating fine particles are stuck only to the corresponding parts, and the non-insulating fine particles can be locally stuck. Note that when the core particles are manufactured by a pulverization method, in the manufacturing process, after coarsely pulverizing the toner composition agglomerates to an appropriate size,
Non-insulating fine particles are uniformly and densely adhered to the surface of the obtained coarsely ground material using the above-mentioned device, and then the non-insulating fine particles are uniformly and densely adhered to the surface in this way. A coarsely ground product may be finely ground.

However, the method for producing the toner for developing electrostatic latent images of the present invention is of course not limited to this method, and may include toner particles to which non-insulating fine particles such as those described above are locally fixed. Any method may be used as long as it can be obtained.

(Example) EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example 1 Ingredients for manufacturing toner A Parts by weight Styrene-〇-butyl methacrylate 100 (softening point 132°C, glass transition point 60°C) Carbon black 8 (manufactured by Mitsubishi Chemical Industries, Ltd.: MA#8) Low molecular weight polypropylene 5 ( Manufactured by Kochu Kasei Kogyo Co., Ltd., Viscol 550P) Nicrosin-based
Dye 5 (manufactured by Orient Kasei Kogyo Co., Ltd.: Bontron N-01) The above materials were thoroughly mixed in a ball mill, and then kneaded on three rolls heated to 140°C. After the kneaded mixture was left to cool, it was roughly pulverized using a feather mill to obtain a pulverized toner having a maximum particle size of 3 mm. Conductive carbon black (COND (JCTEX SC average particle size 2
0 mμ Volume resistivity 0.98 Ω cm (manufactured by Columbian Carbon) 1.0 part by weight was blended into a Henschel mixer, mixed and stirred at a rotation speed of 1500 rpm for 2 minutes, and mixed with crushed toner. did. Thereafter, the mixture obtained here was further finely pulverized using a jet mill (manufactured by Kawasaki Heavy Industries, Ltd.: Kryptron System). Thereafter, air classification was performed to obtain a toner having an average particle size of 8 μm. As a result of observing the surface of the thus obtained toner using a scanning microscope, it was confirmed that conductive carbon black was localized and fixed on the surface of the toner. Furthermore, hydrophobic silica (R-97
4 Average particle size 17 mμ = Nippon Aerosil Kogyo Co., Ltd.) 0.3
Blend parts by weight, put this into a Henschel mixer, and mix 1
The toner was post-treated by mixing and stirring at a rotational speed of 500 rpm for 1 minute to obtain toner A having an average particle size of 8 μm.

Example 2 Production of toner B Polyester resin 100 (manufactured by Kao Corporation: Tufton Kei-1110) Carbon black 8 (manufactured by Mitsubishi Chemical Industries, Ltd.: MA#8) Low molecular weight polypropylene 3 (manufactured by Kochu Kasei Industries, Ltd.: TS-200) Chromium complex dye
5 (manufactured by Hodokugaya Chemical Industry Co., Ltd.: Eizenspiron Black TRH) The above materials were thoroughly mixed in a ball mill, and then kneaded on three rolls heated to 130°C. After cooling the kneaded material,
The powder was coarsely pulverized using a feather mill to obtain a crushed toner having a maximum particle size of 3 mm. To 100 parts by weight of the crushed toner obtained here, 1°0 parts by weight of conductive fine particles (tin oxide-based fine particles T-1 average particle size 0.1 μm volume resistivity 5 Ω cm: manufactured by Mitsubishi Metals) was added. Then, put this in a Henschel mixer, mix and stir at a rotation speed of 1500 rpm for 2 minutes,
It was mixed with crushed toner. Thereafter, the mixture obtained here was further finely pulverized using a jet mill (manufactured by Kawasaki Heavy Industries, Ltd.: Kryptron System).

Thereafter, air classification was performed to obtain a toner having an average particle size of 8 μm.

As a result of observing the surface of the thus obtained toner using a scanning microscope, it was confirmed that tin oxide-based fine particles were localized and fixed on the surface of the toner. Furthermore, resin fine particles (P-10
00 average particle size 50 mμ: manufactured by Nippon Paint Co., Ltd.) 1.0 parts by weight was added to the Henschel mixer, and 150
The toner was post-treated by mixing and stirring at a rotational speed of 0 rpm for 1 minute to obtain toner B having an average particle size of 8 μm.

Example 3 Production of Toner C Styrene 100n-butyl methacrylate 35 Methacrylic acid 52.2
-Azobis-(2,4-0,5 dimethylvaleronitrile) Low molecular weight polypropylene 3 (manufactured by Kaku Kasei Kogyo Co., Ltd.: Viscol 805P) Carbon black 8 (manufactured by Mitsubishi Chemical Industries, Ltd.:
MA#8) Chromium complex dye 3 (manufactured by Odugaya Chemical Industry Co., Ltd.: Eizenspiron Black TRH') The above materials were mixed using a sand stirrer to prepare a polymer composition. This polymerization composition was subjected to a polymerization reaction in an aqueous gum arabic solution with a concentration of 3 w/V% at a temperature of 60° C. for 6 hours while stirring at a rotational speed of 400 Orpm using a stirrer TK Auto Homo Mixer (manufactured by Tokushu Kika Kogyo Co., Ltd.). Ta. After the polymerization reaction was completed, the product was washed with ion-exchanged water, dried, and classified by air to obtain a toner having an average particle size of 8 μm. Furthermore, conductive fine particles (titanium oxide/tin oxide fine particles W-10 average particle diameter 0.2 μm, volume resistivity 50 Ω・Cm: manufactured by Mitsubishi Metals) are sufficiently dispersed in ethanol, and the conductive fine particles are 100% by weight of the toner. The toner is localized and fixed on the surface of the toner using a liquid immersion method using a wet surface modification device, Disper Coat (manufactured by Nisshin Engineering Co., Ltd.), so that the surface treatment is performed at a ratio of 2.0 parts per part. I processed it like this.

As a result of observing the surface of the thus obtained toner using a scanning microscope, it was confirmed that titanium oxide/tin oxide based fine particles were localized and fixed on the surface of the toner. Furthermore, 1.0 parts by weight of resin fine particles (N-300 average particle size 80 mμ manufactured by Nippon Paint Co., Ltd.) was blended with 100 parts by weight of the particles obtained here, and this was placed in a Henschel mixer at a rotation speed of 1500 rpm. The toner was post-treated by mixing and stirring for 1 minute to obtain toner C having an average particle size of 6 μm.

Comparative Example 1 Production of Toner D Toner D having an average particle size of 8 μm was obtained using the same composition and method as in Example 1 except that conductive fine particles were not added to the crushed toner.

Comparative Example 2 Production of Toner E Toner particles having an average particle size of 8 μm were obtained in the same manner as in Example 2 except that conductive fine particles were not added to the crushed toner. After this, conductive fine particles (tin oxide-based fine particles T-1 average particle size 0.1 μm volume resistivity 5Ω・Cm) were added to 100 parts by weight of the particles obtained here. 1.0 parts by weight (manufactured by Co., Ltd.) was added to a Henschel mixer, and mixed and stirred for 1 minute at a rotation speed of 1500 rpm. As a result of observing the surface of the particles thus obtained using a scanning microscope, it was confirmed that the tin oxide-based fine particles were uniformly fixed to the surface of the toner. Furthermore, 1.0 part by weight of resin fine particles (P-1000 average particle size 50 mμ manufactured by Nippon Paint Co., Ltd.) was blended with 100 parts by weight of the obtained particles, and this was placed in a Henschel mixer and mixed for 1 minute at a rotation speed of 150 Orpm. The toner was post-treated by stirring to obtain toner E having an average particle size of 6 μm.

Comparative Example 3 Production of Toner F In Example 3, when surface-treating the toner particle surface with conductive fine particles using Disper Coat (manufactured by Nisshin Engineering Co., Ltd.), the process was carried out in an ethanol-water mixed solution instead of the immersion method. Toner F having an average particle size of 8 μm was obtained using the same composition and method, except that the toner particles and conductive fine particles were sufficiently mixed and stirred to become uniform, and then surface treatment was performed using a slurry method. Regarding Toner F, as a result of observing the surface of the toner before post-treatment with resin fine particles using a scanning microscope, it was confirmed that titanium oxide/tin oxide-based fine particles were evenly fixed to the surface of the toner. It was done.

Manufacture of Carrier In order to subject the toners obtained in the above Examples and Comparative Examples to the evaluation described below, a binder type carrier was manufactured as follows.

Ingredients Part by weight Polyester resin 100 (NE-1i
10: Kao Corporation) Inorganic magnetic powder 500 (EPT-1
000: Manufactured by Toda Industries) Carbon bra I (MA#8: Manufactured by Mitsubishi Chemical Industries, Ltd.)
2 Add the above ingredients to a Henschl mixer.
Thoroughly mix and crush the cylinder part at 180°C.
The mixture was melt-kneaded using an extrusion kneader whose cylinder head was set at 170°C. After cooling the kneaded material, it was coarsely ground using a feather mill, further finely ground using a jet mill, and then classified using a classifier to obtain a carrier having an average particle size of 55 μm.

Evaluation method for various properties Examples 1 to 3 and Comparative Examples 1 to 3 obtained as above
Various properties of toners A to F were evaluated as described below.

Particle size measurement (1) Toner particle size The toner particle size described above was measured using a laser scattering particle size distribution analyzer 5ALD-1100 (manufactured by Konsei Seisakusho Co., Ltd.), and the average particle size was determined. .

(2) Carrier particle size The above carrier particle size is based on Microtrack model 7.
Measured using 995-10SRA (manufactured by Nikkiso Co., Ltd.),
The average particle size was determined.

Adhesion/fixation state of fine particles (non-insulating fine particles) Using a scanning electron microscope, an image of the surface of toner particles after non-insulating fine particles (conductive fine particles) have been fixed (but before post-processing) is recorded on an image analysis device. The state of distribution of fine particles fixed on the surface of each toner particle is measured as follows.

(2) Measure the area ratio occupied by non-insulating fine particles in the captured particle surface image.

(2) Perform operation (2) on 50 particles and calculate the average value. This value is taken as the average adhesion density.

■ The captured particle surface image is
Divide into 20 square areas and measure the area ratio of fine particles existing in each area.

■The area ratio measured in ■ above is 5% relative to the average adhesion density.
Select a region where the amount is 0% or less and calculate its proportion to the total amount region.

(2) Perform operation (2) on 50 particles and calculate the average value. This value is defined as the particle beam density area ratio.

Table 1 shows the fine particle beam density area ratios of the toners obtained in Examples and Comparative Examples by such a measuring method.

Measurement of developed toner adhesion amount on photoreceptor The toner prepared in the above example and the carrier shown in the carrier manufacturing example were mixed toner/carrier = 7/9.
A two-component developer was prepared by mixing at a weight ratio of 3:3. The developer using the toner obtained in Example 1 and Comparative Example 1 is EP-4702 (manufactured by Minolta Camera Co., Ltd.), and the developer using the toner obtained in Example 2.3 and Comparative Example 2.3 For EP-5702 (manufactured by Minolta Camera)
I made an image with . After developing a solid black image, take it out of the machine before the toner latent image reaches the transfer section, suck up the toner from a certain area with a vacuum pump equipped with a filter, and measure the toner overlay to determine the amount of toner developed per unit area. Measure. And the toner development amount is Q, 5mg/cm2 or more is ○, 0.4mg/cm2 or more is △, Q, 4rng/cm
Less than 2 was evaluated as ×. A rank of Δ or higher is practically usable, but a rank of ○ is desirable. The results obtained are shown in Table 1.

Measurement of Transfer Efficiency In measuring the amount of developed toner adhesion, the amount of non-transferred toner is measured by performing the same measurement on the photoreceptor after passing through the transfer section. Transfer efficiency is calculated by taking the ratio between the amount of developed toner and the amount of non-transferred toner.

Transfer efficiency of 90% or more is ○, and 80% or more is △.
Less than 80% was marked as x. A rank of Δ or higher is practically usable, but a rank of ○ is desirable. The results obtained are shown in Table 1.

Table 1 (Effects of the Invention) As stated above, the toner for developing electrostatic latent images of the present invention is as follows:
Non-insulating fine particles are locally adhered to the surface of the insulating toner particles, and the toner particles are characterized by statically behaving as insulating properties.
Since multiple layers of toner can be attached to the latent image during development and the developability is good, sufficient image density can be obtained even if the toner particle size is reduced.On the other hand, electrostatic transfer It can be made as well as conventional insulating toner. In this way, the present invention ensures both good developability and transferability by locally arranging non-insulating fine particles on the toner surface, thus meeting the demand for high image quality in electrophotographic processes. This can be fully addressed.

Patent applicant Minolta Camera Co., Ltd. agent Patent attorney 8 1) Mikio (1 other person)

Claims (1)

[Claims] (1) In a toner in which non-insulating fine particles are fixed to the surface of insulating toner particles, the non-insulating fine particles are locally present on the toner surface, and the toner particles statically behave as insulating properties. Toner for developing electrostatic latent images.