JPH05303236A - Developer and its production - Google Patents

Abstract

PURPOSE:To stably maintain the extent of electrostatic charge and the flowability of a developer from the early stage of use over the entire service life of the developer without deteriorating the productivity of the developer by using a resin obtd. by blending monomers as starting materials and simultaneously carrying out addition polymn. and condensation polymn. as the binding resin of a toner. CONSTITUTION:A carrier is mixed with inorg. fine particles to stick the inorg. fine particles to the surface of the carrier and a toner is electrostatically stuck to the treated carrier by mixing. A conventional mixer is used for the mixing and the amt. of the toner added is usually 1-15 pts.wt. per 100 pts.wt. of the carrier. A resin obtd. by blending monomers as starting materials in a reactor and simultaneously carrying out addition polymn. and condensation polymn. in the same reactor is used as the principal component of the binding resin of the toner. The toner preferably contains a blend of vinyl resin obtd. by addition polymn. with polyester, polyester amide or polyamide obtd. by condensation polymn.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-component dry developer composed of a toner and a carrier and a method for producing the same, which is used in electrophotography, electrostatic recording, electrostatic printing and the like. The present invention relates to a developer in which a powder of magnetic particles and a powder of inorganic fine particles for surface treatment are mixed and adhered, and then a toner is added and adhered, and a manufacturing method thereof.

[0002]

2. Description of the Related Art Conventionally, US Pat. Nos. 2221776 and 22 are known as electrophotographic methods.
As described in the specification of No. 97691, No. 2357809, etc., the photoconductive insulating layer is uniformly charged (charging step), and then the layer is exposed (exposure step) to charge the exposed portion. To form an electrostatic latent image, which is then visualized (development step) by attaching colored charged fine powder called toner to the electrostatic latent image. After the image is transferred to a transfer material such as transfer paper (transfer process), it is permanently fixed by heating, pressure or other appropriate means (fixing process)
A method of steps has been practiced.

The developing methods applied to these electrophotographic methods are roughly classified into a dry developing method and a wet developing method.
The former includes a method using a one-component developer and a method using a two-component developer, and the present invention relates to a method for producing a two-component dry developer. Among the methods using a two-component dry developer, there are a magnetic brush developing method using a magnetic powder carrier and a cascade developing method using a somewhat coarse bead carrier, depending on the type of a toner conveying system. Even when a color developer is used, basically, by the electrophotographic method described above, the steps of [charging] → [exposure] → [development] → [transfer] are repeated a plurality of times, and then the color image is formed by fixing. Done. However, in the exposure step, it differs in that it is exposed by a color separation filter or by writing an image read by a scanner with a laser or the like.

As the toner applied to these developing methods, fine powders in which a coloring agent such as a dye or a pigment is dispersed in a natural or synthetic thermoplastic resin have been generally used. As the synthetic resin type, for example, a binder resin such as a styrene-acrylic copolymer type (polystyrene type) resin, a polyester type resin, an epoxy type resin or the like is mixed with various functional additives such as a colorant, a charge control agent and a wax. Particles obtained by pulverizing the dispersed material to about 1 to 30 μm are used as the toner. A two-component developer composed of such a toner and a carrier is generally required to have a long life, that is, stability and maintainability of image quality in continuous development. For that purpose, the charge amount between the toner and the carrier particles and the resistance of the developer must be maintained within an appropriate range, and it is most desirable that the initial charge amount does not change even in the latter half of the long run.

For the purpose of stably maintaining the charge amount and resistance of these developers, the design and selection of a binder resin, a charge control agent and other additives have been studied from the toner side. On the other hand, from the carrier side as well, various studies have been made on the oxidation treatment method of iron powder, the constituent materials such as ferrite and magnetite, the surface shape of the magnetic powder, the surface coating material and the treatment method thereof. Recently, for example, as a surface coating method for a carrier, a carrier surface-coated by a solution method (JP-A-62-806).
69) and by the dry method (Japanese Patent Laid-Open No. 62-235).
No. 959) has been proposed for the purpose of maintaining the triboelectrification ability of toner for a long period of time. However, these technologies are all related to long-life property, that is, stability improvement of image quality in long-term continuous development, and to improve initial charge fluctuation and resistance fluctuation at the start of use of the developer, It does not improve the stability of the fluidity of the agent.

That is, when a developer prepared by mixing toner and a carrier is set in a developing unit of a printer or a copying machine and the actual development is started, within a few minutes after the start of use, It is pointed out that the change in the carrier particle surface after 100 times of development causes a rapid change in the charge level of the developer called "initial life charge change" and the accompanying undesirable change in the resistance and image quality of the developer. Has been done. Because of this,
An improved method by pre-preparing carrier particles before making a developer has been proposed (US Pat. No. 3,9,9).
70,571). That is, before the toner and the carrier are mixed and stirred to produce the developer, the carrier particles are stirred and mixed in advance with the toner for preliminary preparation including the charge control agent and the binder resin, and the carrier surface of the toner in the initial stage of the developer is used. This is a method of intentionally causing pore filling, scumming and abrasion of the carrier surface, then removing excess pre-preparation toner, and then mixing with the toner to produce a developer. The developer manufactured through such preliminary preparation of carrier particles is expected to have an effect of reducing "variation in initial life charge".

However, in this technique, although the change in the initial life charge can be reduced, the carrier coating agent is peeled off more than necessary during the preliminary preparation, and conversely the long life property is reduced. There were major problems such as the need to manufacture toners having different particle size distributions for preparation, and the fact that the pre-preparation time took several hours, resulting in a significant decrease in developer productivity. ..

Further, without the need for such a mechanical preconditioning treatment of the developer carrier,
A method of stably maintaining the charge amount of the developer over the life of the developer has also been proposed (US Pat. No. 4,828,956).
Specification). However, in this method, two types of toners, the first developer toner and the second developer toner, must be manufactured separately, and when the frictional charge product of each developer is measured, It cannot be said that the manufacturing problem has been solved because the correlation is unknown.

The present invention has been made based on the above circumstances, and its purpose is to improve the charge amount and fluidity of a developer over the entire life of the developer without impairing the productivity of the developer.
(EN) It is intended to provide a developer which can be stably maintained from the time of initial use and a method for producing the same.

[0010]

[Means for Solving the Problems] The inventors of the present invention have conducted various studies for the purpose of solving the above problems, and after mixing and adhering inorganic fine particles on the surface of a carrier, toner is added to the surface of the carrier to electrostatically charge it. When the developer is used in a printer, copier, or other actual machine, the initial charge fluctuation is not observed, and the productivity of the developer is not greatly impaired, and the long run The present invention was completed by discovering that the property can be secured and conducting further research.

That is, the gist of the present invention is (1) a developer in which a carrier and inorganic fine particles are mixed to adhere the inorganic fine particles to the carrier surface, and then the toner is electrostatically mixed and adhered to the carrier surface. A manufacturing method, characterized in that the main component of the binder resin of the toner is a resin obtained by blending raw material monomers in the same reaction vessel and carrying out addition polymerization and polycondensation in parallel. A method for producing a developer, and (2) a developer comprising a carrier in which inorganic fine particles are adhered to the surface of a carrier and a toner, wherein the main component of the binder resin of the toner is blending raw material monomers in the same reaction container. A resin obtained by carrying out addition polymerization and polycondensation in parallel and containing 1 to 15 parts by weight of the toner with respect to 100 parts by weight of a carrier. About.

In the production method of the present invention, the inorganic fine particles are first adhered to the carrier surface by mixing the carrier and the inorganic fine particles. As the inorganic fine particles used for the treatment of the surface of the carrier, it is possible to use all the inorganic fine particles known to be conventionally used for electrophotography.

Specifically, for example, silica, alumina, titanium oxide and tin oxide, and the surface of which is made conductive by antimony, barium titanate,
Magnesium titanate, calcium titanate, strontium titanate, zinc oxide, silica sand, clay, mica, wollastonite, diatomaceous earth, chromium oxide, cerium oxide, red iron oxide, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, Examples thereof include barium carbonate, calcium carbonate, silicon carbide and silicon nitride. In particular, even in the case of silica, the silanol groups on the surface thereof are preferably hydrophobized with hexamethyldisilazane or dimethyldichlorosilane.

The particle size of these inorganic fine particles depends on the carrier and the particle size of the toner to be used and cannot be specified unconditionally, but it is generally one of the average particle size of the toner used.
It is possible to use one that is one-third or less. More preferably, those having a primary average particle diameter of 1 / 10,000 to 1/100 are more effective. If the average particle size is larger than 1/10 of the toner particle size, the surface of the photosensitive member tends to be damaged, and if the average particle size is smaller than 1 / 10,000, the particles are easily scattered and are difficult to handle.
Specifically, the average primary particle diameter of the inorganic fine particles is usually 0.0
01-0.1 μm, preferably 0.005-0.05 μ
m is used. In the present invention, the above-mentioned inorganic fine particles may be the same as or different from those used in the surface treatment of the toner described later. Also,
These may be used alone or in combination of two or more.

The carrier used in the present invention can be selected from various porous or non-porous materials and is usually 20 to 500 μm, preferably 55 to 16 μm.
Those having an average particle size of 0 μm are used. Specifically, for example, glass beads, inorganic salt crystals, hard resin particles, metal fine particles and the like are used. Further, magnetic carrier particles can be used in the present invention, and examples thereof include iron powder, nickel powder, and ferrite powder. The surface of these magnetic carrier particles is styrene acrylic resin, polyester resin, silicone resin, silicone acrylic resin, or various fluorocarbons such as fluorocarbon resin, such as kiner, polytetrafluoroethylene, polyvinylidene fluoride and vinyl fluoride and tetrafluorocarbon. It may be coated with a resin containing a fluoroethylene copolymer or a mixture thereof.

In the present invention, when the inorganic fine particles are mixed and attached to these carriers, the addition amount of the inorganic fine particles is
It cannot be unconditionally specified because it depends on the mixing device or the mixing conditions, but it may be within the range in which it is possible to sufficiently suppress the electrostatic fluctuation in the initial stage of printing durability use and not to recognize the occurrence of problems such as black spots. It is necessary and usually 0.001 to 0.5 part by weight, preferably 0.005 to 0.3 part by weight, is used with respect to 100 parts by weight of the carrier. In this case, if the addition amount is less than 0.001 part by weight, the effect of coating or scumming on the surface of the carrier or the pores is small, and the effect effective in reducing the initial change in the charge amount cannot be obtained, which is not preferable. On the other hand, if the amount added exceeds 0.5 part by weight, the amount of free inorganic fine particles increases, and the inorganic fine particles move to the surface of the toner to change the chargeability of the toner, or secondary aggregates thereof are generated, resulting in a photoreceptor. It is not preferable because it may cause scratches that become the core of black spots.

Here, the black spot is a kind of filming on the photosensitive member and appears as a black spot on the visible image. This is remarkable when the inorganic fine particles are considerably hard, so that it is remarkable when the photoconductor has a relatively small hardness such as a selenium-tellurium-based material or an organic photoconductor, and it is considered that the photoconductor is relatively hard. However, the same problem occurs when it is made of a selenium-arsenic material which is fragile against mechanical impact.

The apparatus used for mixing is not particularly limited, and is generally used, for example, horizontal cylindrical type, V type, W type container rotary type mixer, Nauta mixer, container mixer and the like. A mixing device is used. Among the above mixing devices, for example, when a container rotary mixer is used, the peripheral speed of rotation in mixing the carrier and the inorganic fine particles is 20 to 100 m / m depending on their mixing volume.
It is preferably in the range of minutes. If the rotational peripheral speed exceeds 100 m / min, the mixing effect becomes unnecessarily large, wear of the carrier surface and reaggregation of the inorganic fine particles proceed, which is not preferable. On the other hand, when the rotation peripheral speed is lower than 20 m / min, the inorganic fine particles are not evenly adhered to the carrier surface, and the effect of adhesion becomes small.

In the method for producing the developer of the present invention, the surface of the carrier is treated with the inorganic fine particles as described above, but in the present invention, the carrier thus treated is further electrostatically mixed with the toner. Attach it. The method of mixing and adhering the toner may be any method used in the preparation of an ordinary two-component developer, and examples thereof include the same method as in the case of the treatment of the carrier surface described above. In this case, the above-mentioned mixing device or the like can be used. Also,
The mixing conditions using these mixing devices are not particularly limited, and may be ordinary conditions. At this time, the addition amount of the toner is usually 1 to 15 parts by weight, preferably 2 to 10 parts by weight, based on 100 parts by weight of the carrier.

The toner is generally composed of a binder resin and additives such as a charge control agent, a colorant, a fluidity improver, a cleaning improver and a release agent. The toner used in the present invention is It is a toner in which a resin obtained by blending raw material monomers in the same reaction container and carrying out addition polymerization and polycondensation in parallel is a main component of a binder resin. Among such toners, a toner containing a resin obtained by blending a vinyl-based resin obtained by addition polymerization (radical polymerization) and a polyester, polyesteramide or polyamide obtained by polycondensation as a main component of the binder resin is preferable. The vinyl-based resin is not particularly limited, but styrene-acrylic resin is mentioned as a preferred example, and in the present invention, for example, a resin obtained by blending styrene-acrylic resin and polyester is used as the main component of the binder resin. Toner is used. The particle size of the toner used in the present invention depends on the size of carrier particles, but is usually 6
-15 μm, preferably 8-13 μm is used. The toner used in the present invention may have either a positive charging property or a negative charging property.

As the binder resin of the toner in the present invention, the resin obtained by blending the raw material monomers in the same reaction vessel and carrying out addition polymerization and polycondensation in parallel as described above is the main binder resin. A preferred embodiment of the present invention is a case where the vinyl resin is obtained by addition polymerization (radical polymerization) and the polyester, polyesteramide or polyamide is obtained by condensation polymerization. That is, a preferable main component of the binder resin can be obtained by blending a vinyl monomer, an alcohol, and a carboxylic acid and / or a derivative thereof as raw material monomers, and performing addition polymerization and polycondensation in parallel as described above. it can. The raw material monomers and the like will be described below.

In the present invention, when a vinyl-based resin is obtained by addition polymerization, the following vinyl-based monomers, if necessary, a crosslinking agent, and a polymerization initiator such as a peracid or an azo compound are used.

Typical monomers used for constituting the vinyl resin include, for example, styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-ethylstyrene, 2,4 −
Styrene or styrene derivatives such as dimethylstyrene, p-chlorostyrene, vinylnaphthalene, etc., ethylenically unsaturated monoolefins such as ethylene, propylene, butylene, isobutylene, etc., such as vinyl chloride,
Vinyl esters such as vinyl bromide, vinyl fluoride, vinyl acetate, vinyl propionate, vinyl formate, vinyl caproate, etc., such as acrylic acid, methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, N-Butyl acrylate, isobutyl acrylate, tert-butyl acrylate, amyl acrylate, cyclohexyl acrylate, n-octyl acrylate, isooctyl acrylate, decyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, acrylic acid Stearyl, methoxyethyl acrylate, 2-hydroxyethyl acrylate, glycidyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, α-
Methyl chloroacrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, tert-methacrylate.
Butyl, amyl methacrylate, cyclohexyl methacrylate, n-octyl methacrylate, isooctyl methacrylate, decyl methacrylate, lauryl methacrylate,
2-ethylhexyl methacrylate, stearyl methacrylate, methoxyethyl methacrylate, 2-methacrylic acid
Substitution of ethylenic monocarboxylic acids such as hydroxyethyl, glycidyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, etc. and their esters, such as acrylonitrile, methacrylonitrile, acrylamide, etc. Ethylenic dicarboxylic acids such as dimethyl maleate and substituted products thereof, such as vinyl ketones such as vinyl methyl ketone, vinyl ethers such as vinyl methyl ether, and vinylidene halides such as vinylidene chloride, such as N -There are N-vinyl compounds such as vinylpyrrole and N-vinylpyrrolidone.

When a crosslinking agent is added, for example, divinylbenzene, divinylnaphthalene, polyethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, 1,3-butylene glycol dimethacrylate, 1,6-hexylene glycol dimethacrylate. Methacrylate, neopentyl glycol dimethacrylate, dipropylene glycol dimethacrylate, polypropylene glycol dimethacrylate, 2,
2'-bis (4-methacryloxydiethoxyphenyl) propane, 2,2'-bis (4-acryloxydiethoxyphenyl) propane, trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, General cross-linking agents such as dibromoneopentyl glycol dimethacrylate and diallyl phthalate can be appropriately used (combined with two or more if necessary). These crosslinkers are
When the amount used is large, the toner is less likely to be melted by heat, resulting in poor heat fixing property or heat pressure fixing property. Further, when the amount used is small, it is difficult to prevent the offset phenomenon in which a part of the toner adheres to the roller surface without being completely fixed to the paper and is transferred to the next paper during heat roller fixing. Further, the amount of these cross-linking agents used is 0.001 to 15% by weight, preferably 0.1 to 15% by weight, based on the polymerizable monomer.
It is recommended to use 10 to 10% by weight.

Further, as the polymerization initiator used in producing the vinyl resin, 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2'-azobisisobutyronitrile, 1 , 1'-Azobis (cyclohexane-1-carbonitrile), 2,2'-azobis-4-methoxy-2,4-dimethylvaleronitrile, other azo or diazo polymerization initiators or benzoyl peroxide, methyl ethyl ketone per Examples thereof include peroxide type polymerization initiators such as oxide, isopropyl peroxycarbonate, cumene hydroperoxide, 2,4-dichlorobenzoyl peroxide, lauroyl peroxide and dicumyl peroxide. Two or more polymerization initiators may be mixed and used for the purpose of controlling the molecular weight and molecular weight distribution of the polymer, the reaction time, or the like. The amount of the polymerization initiator used is 100
0.1-20 parts by weight, preferably 1-1
0 parts by weight.

In the present invention, when a polyester is obtained by polycondensation, an alcohol and a carboxylic acid, or a derivative of a carboxylic acid such as a carboxylic acid ester or a carboxylic acid anhydride is used as a raw material monomer.

As the dihydric alcohol component, polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (3.
3) -2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene (2.0) -2,2-bis (4
-Hydroxyphenyl) propane, polyoxypropylene (2.0) -polyoxyethylene (2.0) -2,2
-Bis (4-hydroxyphenyl) propane, polyoxypropylene (6) -2,2-bis (4-hydroxyphenyl) propane and other alkylene oxide adducts of bisphenol A, ethylene glycol, diethylene glycol, triethylene glycol, 1, 2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, neopentyl glycol, 1,4-butenediol, 1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanediene methanol,
Examples include dipropylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, bisphenol A, hydrogenated bisphenol A and the like.

Examples of trihydric or higher alcohol components include sorbitol, 1,2,3,6, -hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,
2,4, -butanetriol, 1,2,5, -pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol,
Trimethylolethane, trimethylolpropane, 1,
3,5, -trihydroxymethylbenzene etc. are mentioned.

The acid component is a carboxylic acid component 2
Monovalent monomers include maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, malonic acid, n-dodecenyl succinic acid, isodoic acid. Decenyl succinic acid, n-dodecyl succinic acid,
Isododecyl succinic acid, n-octenyl succinic acid, n-
Examples thereof include octyl succinic acid, isooctenyl succinic acid, isooctyl succinic acid, etc., and anhydrides or lower alkyl esters of these acids.

Examples of the trivalent or higher carboxylic acid component include 1,2,4, -benzenetricarboxylic acid, 2,5,5.
7, -naphthalene tricarboxylic acid, 1,2,4, -naphthalene tricarboxylic acid, 1,2,4, -butane tricarboxylic acid, 1,2,5, -hexane tricarboxylic acid, 1,
3-dicarboxyl-2-methyl-2-methylenecarboxypropane, 1,2,4-cyclohexanetricarboxylic acid, tetra (methylenecarboxyl) methane, 1,
Examples include 2,7,8-octanetetracarboxylic acid, pyromellitic acid, empol trimer acid, and the like, and anhydrides or lower alkyl esters of these acids.

In the present invention, when a polyester amide or a polyamide is obtained by polycondensation, polyamines among the raw material monomers forming the amide component are, for example, ethylenediamine, pentamethylenediamine, hexamethylenediamine, diethylenetriamine, iminobispropylamine, Examples thereof include polyamines such as phenylenediamine, xylylenediamine and triethylenetetramine, aminocarboxylic acids such as 6-aminocaproic acid and ε-caprolactam, and amino alcohols such as propanolamine.

To produce a polyester resin, a polyesteramide resin, or a binder resin in which a polyamide resin and a vinyl resin are blended using the above-mentioned raw material monomers, polyester or polyesteramide contained in a reaction vessel, or A mixture of the raw material monomer of the vinyl resin and the polymerization initiator is dropped into the raw material monomer mixture of the polyamide and premixed, and the radical polymerization reaction is first performed to complete the polymerization reaction to obtain the vinyl resin, and then the reaction temperature. And a polycondensation to obtain a polyester or polyesteramide or polyamide to complete the polymerization reaction. In this way, a binder resin in which two kinds of resins are effectively mixed and dispersed can be obtained by a method of allowing two independent reactions to proceed in parallel in a reaction vessel. In the above parallel reaction, the progress and completion of the two polymerization reactions do not have to be simultaneous in time, and the reaction temperature and time are appropriately selected according to the respective reaction mechanisms to proceed and complete the reaction sequentially. May be.

By such a production method, a binder resin composed of a blend of a polycondensation resin selected from the above polyester, polyesteramide or polyamide and a vinyl resin such as styrene / acrylic resin can be obtained. At that time, the mixing ratio of the polycondensation resin and the vinyl resin is preferably 10 to 90 parts by weight of the polycondensation resin and 90 to 10 parts by weight of the vinyl resin. Further, it is preferable that the obtained binder resin has a softening point of 95 to 170 ° C and a glass transition temperature of 50 to 80 ° C. The softening point and glass transition temperature of the binder resin can be easily adjusted by adjusting the amount of the polymerization initiator or the catalyst in the raw material monomer mixture or selecting the reaction conditions.

In the present invention, if the molecular weight of the resin produced in one of the reaction paths is lowered, the pulverizability of the binder resin can be improved. Particularly for the vinyl-based resin portion, if the number average molecular weight is 11,000 or less, it is effective for improving the pulverizability of the binder resin. The number average molecular weight of 11,000 or less can be easily achieved by using a large amount of polymerization initiator or using a chain transfer agent.

Next, various additives used for preparing the toner in the present invention will be described. The charge control agent is not particularly limited, and as the negatively chargeable toner, one kind or two or more kinds are used from all the negatively chargeable charge control agents known to be conventionally used for electrophotography. For example, metal-containing azo dyes such as "Varifast Black 3804", "Bontron S-31",
"Bontron S-32", "Bontron S-34",
"Bontron S-36" (above, manufactured by Orient Chemical Co., Ltd.), "Aizenspiron Black TVH" (manufactured by Hodogaya Chemical Co., Ltd.), a copper phthalocyanine dye, a metal complex of an alkyl derivative of salicylic acid, such as "Bontron E-8"
4 "(manufactured by Orient Chemical Co., Ltd.), quaternary ammonium salts such as Copy Charge NX VP434 (manufactured by Hoechst), and the like.

Further, as the positively chargeable toner, one kind or two or more kinds are used from all the positively chargeable charge control agents known to be conventionally used for electrophotography. As a specific example, an imidazole derivative such as "PLZ-
2001 "," PLZ-8001 "(above, manufactured by Shikoku Kasei Co., Ltd.), triphenylmethane derivative such as CO
PY BLUE PR (manufactured by Hoechst), quaternary ammonium salt compound, for example, "Bontron P-51" (manufactured by Orient Chemical Co., Ltd.), Copy Charge PXVP4
35 (manufactured by Hoechst), polyamine resins such as cetyltrimethylammonium bromide, for example, "AFP-B"
(Manufactured by Orient Chemical Co., Ltd.) and the like. As another method of obtaining a positively chargeable toner, a styrene-acrylic resin obtained by copolymerizing the above-mentioned amino group-containing copolymerizable monomer can be used by mixing with another binder resin. .. Further, if necessary, one type or two or more types of the above-mentioned positively chargeable charge control agent may be used in this system.

It is also possible to use the main charge control agent and a charge control agent of opposite polarity in combination, and the amount of the charge control agent of the opposite chargeability is 1/2 or less of the amount of the charge control agent of the main chargeability. In this case, even if continuous development is performed on 50,000 sheets or more, a good visible image can be obtained without a decrease in density. The above charge control agent is contained in the binder resin in an amount of 0.1 to 8.0% by weight, preferably 0.2 to 5.0% by weight.

As the colorant, chromatic dyes or pigments such as carbon black and grafted carbon black obtained by coating the surface of carbon black with a resin are used, but all known ones can be used, and particularly limited. It is not something that will be done.

For example, yellow has C.I. I. Solvent Yellow 21, C.I. I. Solvent Yellow 114,
C. I. Solvent Yellow 77, C.I. I. Pigment Yellow 12, C.I. I. Pigment Yellow 14, C.I.
I. Disperse Yellow 164 and the like can be mentioned. C. for magenta. I. Solvent Red 49, C.I. I. Solvent Red 128, C.I. I. Pigment Red 1
3, C.I. I. Pigment Red 48.2, C.I. I. Disperse Red 11 and the like can be mentioned. Cyan is C.I.
I. Solvent Blue 25, C.I. I. Solvent Blue 94, C.I. I. Pigment Blue 15.3 and the like can be mentioned.

If desired, the toner of the present invention may contain a fluidity improving agent, a cleaning property improving agent and the like. As the fluidity improver, for example, silica,
Alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, silica sand, clay, mica, wollastonite, diatomaceous earth, chromium oxide, cerium oxide, red iron oxide, antimony trioxide, Magnesium oxide, zirconium oxide,
Examples thereof include barium sulfate, barium carbonate, calcium carbonate, silicon carbide and silicon nitride. Fine silica powder is particularly preferable.

The fine powder of silica is Si-O-Si.
It is a fine powder having a bond and may be produced by a dry method or a wet method. In addition to anhydrous silicon dioxide, aluminum silicate, sodium silicate,
It may be any of potassium silicate, magnesium silicate, zinc silicate, etc., but those containing 85% by weight or more of SiO ₂ are preferable. Further, a fine powder of silica surface-treated with a silane coupling agent, a titanium coupling agent, a silicone oil, a silicone oil having an amine in a side chain, or the like can be used.

Examples of the cleaning property improver include metal salts of higher fatty acids typified by zinc stearate, fine particles of fluorine type high molecular weight particles, and fine particles of silicone resin.

If desired, a release agent may be used in the toner of the present invention for the purpose of improving offset resistance in heat roller fixing. For example, any offset preventive agent such as polyolefin, fatty acid metal salt, fatty acid ester, partially saponified fatty acid ester, higher fatty acid, higher alcohol, paraffin wax, amide wax, polyhydric alcohol ester, silicon varnish, aliphatic fluorocarbon, and silicone oil can be used. One or more of the above may be included.

The polyolefin is, for example, a resin such as polypropylene, polyethylene, polybutene and the like, and has a softening point of 80 to 160 ° C. Examples of the fatty acid metal salt include metal salts of maleic acid and zinc, magnesium, calcium, etc .; stearic acid and zinc, cadmium, barium, lead, iron, nickel, cobalt,
Metal salts with copper, aluminum, magnesium, etc .; dibasic lead stearate; oleic acid and zinc, magnesium,
Metal salts with iron, cobalt, copper, lead, calcium, etc .; Metal salts with palmitic acid and aluminum, calcium, etc .: Caprylate; Lead caproate: Metal salts with linoleic acid, zinc, cobalt, etc .; Calcium ricinoleate A metal salt of ricinoleic acid and zinc, cadmium or the like, or a mixture thereof. Examples of the fatty acid ester include maleic acid ethyl ester, maleic acid butyl ester, stearic acid methyl ester, stearic acid butyl ester, palmitic acid cetyl ester, montanic acid ethylene glycol ester, and the like. Examples of the partially saponified fatty acid ester include partially saponified calcium of montanic acid ester. Examples of the higher fatty acid include dodecanoic acid, lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid,
Examples thereof include linoleic acid, ricinoleic acid, arachidic acid, behenic acid, lignoceric acid, ceracoleic acid and the like, and mixtures thereof. Examples of the higher alcohols include dodecyl alcohol, lauryl alcohol, myristyl alcohol, palmityl alcohol, stearyl alcohol, araquin alcohol, behenyl alcohol and the like. Examples of the paraffin wax include natural paraffin, micro wax, synthetic paraffin, and chlorinated hydrocarbon. Examples of the amide wax include stearic acid amide, oleic acid amide, palmitic acid amide, lauric acid amide, behenic acid amide, methylenebisstearamide,
Examples thereof include ethylene bis stearamide. Examples of the polyhydric alcohol ester include glycerin stearate, glycerin ricinoleate, glycerin monobehenate, sorbitan monostearate, propylene glycol monostearate, and sorbitan trioleate. Examples of the silicon varnish include methyl silicon varnish and phenyl silicon varnish. Examples of the aliphatic fluorocarbon include low-polymerization compounds of tetrafluoroethylene and propylene hexafluoride, and fluorine-containing surfactants described in JP-A-53-124428.

In addition to these, various additives can be used in the toner of the present invention. For example, an additive for adjusting developability, for example, fine particle powder of a polymer of methacrylic acid methyl ester may be used.
Further, a small amount of carbon black may be used for toning and resistance adjustment. As the carbon black, conventionally known ones, for example, various ones such as furnace black, channel black and acetylene black can be used.

The developer of the present invention is subjected to a treatment of intentionally preliminarily adhering the inorganic fine particles having a small particle size to the surface of the developer carrier by physical adhesion or electrostatic adhesion. It is obtained by electrostatically adhering to the carrier by adding a toner such as the resin as the main component of the binder resin to the carrier. It is possible to reduce the influence of migration and adhesion of fine powder toner. The physical adhesive force here means van der Waals force or image force.

On the other hand, in the case where the surface of the carrier is not previously subjected to the treatment as in the present invention, immediately after the developer is mixed with the toner to produce the developer, the carrier particles are attached to the surface other than the toner particles. There are few of them, and the developer retains high chargeability. However, once the toner is set in the developing tank of a printer or a copying machine and the heat is generated by mechanical stirring and friction when the development is started, the surface treatment agent and minute toner applied to the toner surface are Adhesion or fusion is started on the surface or in the pores of the carrier, whereby the effective area of charge imparting of the carrier is sharply reduced, and a large charge fluctuation occurs. That is, for example, if the charge polarity of the toner is positive and the charge polarity of the carrier or the coating material on the surface of the carrier is negative, the positive charge control agent present at the interface when the toner is pulverized. And the like are electrostatically transferred to the carrier surface by contact with the negative carrier surface many times during printing, and substantially neutralize the negative property of the carrier surface. For this reason, the ability of the carrier to impart positive charge to the toner is reduced, and a large variation in charge amount is involved.

In the present invention, as described above, since the inorganic fine particles are preliminarily adhered to the surface of the carrier and the charge imparting ability of the carrier is appropriately reduced from the initial stage of use, even if the initial stage of printing durability, the surface of the carrier becomes a toner. Even if the surface treatment agent migrates or is contaminated due to the adhesion of toner fine particles, the fluctuation of the charge amount can be reduced. Therefore, the fluidity of the developer and the resistance of the developer can be stabilized.

The developer obtained by the manufacturing method of the present invention can be applied to various developing methods. For example, there are a magnetic brush developing method, a cascade developing method, a method using a conductive magnetic toner, a method using a high resistance magnetic toner, a fur brush developing method, a powder cloud method and an impression developing method.

[0050]

EXAMPLES The present invention will be described in more detail below with reference to examples. However, the present invention is not limited to the following examples. Further, the number of parts of the composition ratio shown below is
Unless stated otherwise, all parts are by weight. In addition, production examples of the binder resin and the toner used in the present invention, and production examples of the coated carrier particularly suitable in the present invention are also shown below.

Resin Production Example 1 700 g of styrene, 300 g of butyl methacrylate, and 50 g of dicumyl peroxide as a polymerization initiator were placed in a dropping funnel as a vinyl resin monomer. Polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane 390 g, isophthalic acid 120 g, 1,2,5-benzenetricarboxylic acid 38 g and dibutyltin oxide 1 g
Was placed in a glass 5-liter four-necked flask, equipped with a thermometer, a stainless stir bar, a downflow condenser, and a nitrogen inlet tube, and stirred at 135 ° C under a nitrogen stream in a mantle heater. On the other hand, the vinyl resin monomer and the polymerization initiator were dropped from the dropping funnel over 4 hours. While maintaining the temperature at 135 ° C, the mixture was aged for 5 hours, heated, and then reacted at 220 ° C. The degree of polymerization was traced by measuring the softening point according to ASTM E28-67, and the reaction was terminated when the softening point reached 120 ° C. The obtained resin was a pale yellow solid, and the glass transition temperature by differential thermal analysis (hereinafter abbreviated as DSC) had only one peak and was 62 ° C. Since there is one peak in this way, it can be seen that the dispersion of the resins is good. Let the said resin be binder resin (1).

Resin Production Example 2 As a vinyl resin monomer, styrene 820 g, 2
180 g of ethylhexyl acrylate and 40 g of azobisisobutyronitrile as a polymerization initiator are placed in a dropping funnel. Polyoxyethylene (2.2) -2,2-bis (4-hydroxyphenyl) propane 390 g, fumaric acid 12 g, isododecenyl succinic anhydride 55 g, terephthalic acid 110 g
Then, 1 g of dibutyltin oxide is placed in a glass 5-liter four-necked flask, and a thermometer, a stainless stir bar, and a nitrogen introduction tube are attached. The subsequent operations and polymerization reaction conditions are the same as in Example 1. When the glass transition temperature of the obtained resin was determined by DSC, it was found that there was only one peak at 60 ° C., and that the dispersion of the resins was good as in Example 1. Let the said resin be binder resin (2).

Toner Production Example 1 Binder resin (1) 88 parts Carbon black "Regal 400R" (manufactured by Cabot) 8 parts Negatively chargeable charge control agent "Eisenspiron black T-77" 2 parts (manufactured by Hodogaya Chemical Co., Ltd.) ) Wax "Viscole NP-105" (manufactured by Mitsui Petrochemical Industry Co., Ltd.) 2 parts After thoroughly mixing the above raw materials with a Henschel mixer, kneading with a twin-screw extruder equipped with a barrel cooling device, cooling,
After coarsely crushing, it was crushed with a jet mill and further classified with an air classifier to obtain fine powder having an average particle size of 11 μm. For 1000 g of this fine powder, the hydrophobic silica "CA
2.0 g of “B-O-SIL TS-530” (manufactured by Cabot Corporation) was added and mixed and attached using a Henschel mixer to obtain a negatively chargeable toner 1.

Toner Production Example 2 Binder resin (2) 88 parts Carbon black "Regal 330R" 7 parts Positively chargeable charge control agent "Bontron N-07" 2 parts (Orient Chemical Co.) Positively chargeable charge control agent " TP-415 "(manufactured by Hodogaya Chemical Co., Ltd.) 1 part Wax" Luwax ES9675 "(manufactured by BASF) 2 parts The above raw materials are kneaded and pulverized in the same manner as in Toner Manufacturing Example 1.
The particles were classified to obtain 11 μm fine powder. 1000 of this fine powder
Hydrophobic silica “HVK-2150” (Wac
ker chemie) was added and mixed and adhered using a Henschel mixer to obtain a positively chargeable toner 2.

Example of manufacturing coated carrier Ferrite carrier F-100 manufactured by Powder Tech Co., Ltd.
Silicone acrylic resin (manufactured by Toshiba Silicone Co., Ltd.) in which 1000 parts (average particle size 100 μm) was heated and maintained at 60 ° C. while being fluidized in a fluidized bed and dissolved in 5% with toluene.
Spray TSR-171) 10 parts (resin equivalent),
After drying for another 20 minutes, 200 ° C in an electric furnace,
Heat treatment was performed for 30 minutes to obtain a coated carrier.

Example 1 Monomethyl Silicon Coated Ferrite Carrier F96-100 (average particle size 100 μm) manufactured by Powder Tech Co., Ltd.
Hydrophobic silica “AEROS” as inorganic fine particles in 960 g
19.2 mg (0.002 parts by weight) of “IL R-972 (average particle size 0.02 μm)” (manufactured by Nippon Aerosil Co., Ltd.) is divided into two equal parts and sandwiched in a carrier layer in a sandwich state. Preparation, V type blender V-
Rotational peripheral speed of 40 m / using a 10 (mixer manufactured by Tokuju Kosakusho)
The mixture was mixed for 15 minutes for 15 minutes to uniformly deposit the inorganic fine particles on the surface of the carrier. Next, 40 g of the negatively chargeable toner 1 was added to this preliminarily prepared carrier and mixed under the same conditions for 15 minutes to obtain a developer 1.

Example 2 Example 2 except that the inorganic fine particles used for the surface treatment of the carrier of Example 1 were changed to amorphous titanium oxide "Titania IT-UD (average particle size 0.02 μm)" (made by Idemitsu Kosan Co., Ltd.). Developer 2 was obtained in exactly the same manner as in 1.

Example 3 Zirconium oxide “NS-3Y (average particle size 0.02 μm)” containing 3 mol% of yttrium oxide as the inorganic fine particles used for the surface treatment of the carrier of Example 1 (manufactured by Nippon Shokubai Co., Ltd.) Developer 3 was obtained in the same manner as in Example 1 except that the content was changed to

Example 4 Coated Carrier 9 Coated Carrier Obtained in Production Example
Hydrophobic silica "AEROSI" as inorganic fine particles in 60 g
LR-972 (average particle size 0.02 μm) ”(manufactured by Nippon Aerosil Co., Ltd.) 28.8 mg (0.003 parts by weight)
Is divided into two equal parts, and the mixture is charged into the carrier layer so that it is sandwiched between them. Using a W cone blender (Mixer manufactured by Tokuju Kosakusho), the rotational peripheral speed is 30 m / min.
After mixing for a minute, the inorganic fine particles were uniformly attached on the surface of the carrier. Next, 40 g of the positively chargeable toner 2 was added to this preliminarily prepared carrier and mixed for 10 minutes under the same conditions to obtain a developer 4.

Example 5 Exactly the same method as in Example 4 except that the inorganic fine particles of Example 4 were changed to amorphous titanium oxide "Titania IT-UD (average particle size 0.02 μm)" (made by Idemitsu Kosan Co., Ltd.). Thus, a developer 5 is obtained.

Example 6 Except that the inorganic fine particles of Example 4 were changed to zirconium oxide “NS-3Y (average particle size 0.02 μm)” containing 3 mol% yttrium oxide (manufactured by Nippon Shokubai Co., Ltd.). ,
Developer 6 was obtained in the same manner as in Example 4.

Comparative Example 1 Monomethyl Silicon Coated Ferrite Carrier F96-100 (average particle size 100 μm) manufactured by Powder Tech Co., Ltd.
960 g was charged into a V-type blender V-10 (Mixer manufactured by Tokuju Kosakusho Co., Ltd.), and 40 g of the negatively chargeable toner 1 was added at a rotational peripheral speed of 40 m / min without performing the treatment using the inorganic fine particles as described above. After mixing for 15 minutes, Comparative Developer 1 was obtained.

Comparative Example 2 Coated Carrier 9 Obtained in Production Example of Coated Carrier
60 g was charged into a W corn blender (Mixer manufactured by Tokuju Seisakusho Co., Ltd.), 40 g of the positively chargeable toner 2 was added thereto without the treatment using the above-mentioned inorganic fine particles, and the rotation peripheral speed was 30.
Comparative developer 2 was obtained by mixing at m / min for 10 minutes.

Test Example 1 (1) Evaluation of Charge Amount For the developers manufactured in Examples 1 to 6 and Comparative Examples 1 and 2, Developers 1 to 3 and Comparative Developer 1 are the copiers manufactured by Toshiba Corporation. BD-9240 "modified machine is used under normal standard setting conditions. For developers 4-6 and comparative developer 2, Sharp Co., Ltd. copier" SF-8800 "modified machine is modified under normal standard setting conditions. Used in the normal environment (23
An evaluation test of the charge amount was performed at 50 ° C. and 50% RH.
The amount of charge is measured at the initial stage, 1,000 sheets, 10,000 sheets and 10 sheets.
The developers were sampled after printing ten thousand sheets, and each developer was sampled as follows. Moreover, the initial fluctuation of the specific charge was obtained as the difference between the initial charge and the specific charge after printing 1,000 sheets. The device used was a blow-off type charge amount measuring device, and this device was a specific charge measuring device equipped with a Faraday cage, a condenser, and an electrometer. As the measuring method, W (g) (about 3.0 g) of the prepared developer was put in a measuring cell made of brass equipped with a stainless mesh of 325 mesh (size which carrier particles do not pass). Next, suction was performed for 90 seconds at a pressure indicated by the flow meter from the suction port at 3 liter / min to remove only the toner from the cell. The voltage of the electrometer 90 seconds after the start of the suction was set to V (volt). Here, if the electric capacity of the condenser is C (μF), the specific charge Q / m of this toner is obtained by the following equation. Q / m (μc / g) = C × V / m Here, m is the weight of the toner contained in the development in W (g), and the weight of the toner in the developer is T (g), When the weight of the developer is D (g), the toner concentration of the sample is T
/ D × 100 (%), and m is calculated by the following formula. m (g) = W × T / D The results are also shown in Table 1.

(2) Evaluation of image Using the same evaluation equipment as in the above-mentioned evaluation test of charge amount, a printing durability test was carried out in a normal environment (23 ° C., 50% RH) under normal standard setting conditions. The image density and background stain were evaluated by the following methods. The image density was evaluated by measuring the image density using a Macbeth reflection densitometer RD-914 while printing 100,000 sheets using each of the above devices. Regarding the evaluation of the background stain, a colorimetric color difference meter Z-1001 was similarly measured while printing 100,000 sheets.
Using DP (manufactured by Nippon Denshoku Industries Co., Ltd.), the value obtained by subtracting the value of the whiteness of the non-image area after development from the whiteness of the surface of the unused paper was taken as the relative comparison value of the background stain, and Evaluation was made by comparing the values. The results are shown in Table 1.

(3) Evaluation of blocking With respect to the evaluation of blocking of the developer, the developer after printing 100,000 sheets in the above-mentioned image evaluation was taken out from the developing tank, spread on a white plate, and visually and by hand. It was done by touching and comparing. The results are also shown in Table 1.

Test Example 2 For the developer 1 and the comparative developer 1 manufactured in Example 1 and Comparative Example 1, a copying machine "BD-924" manufactured by Toshiba Corporation was used.
The same evaluation as in Test Example 1 was performed under high temperature and high humidity (35 ° C., 85% RH) using a modified machine of “0” under normal standard setting conditions. The results are also shown in Table 1.

[0068]

[Table 1]

As shown in the results of Table 1, in the normal environment, the developers 1 to 6 prepared in Examples 1 to 6 were 1 at the initial stage.
It showed a stable specific charge after printing 0,000 sheets, had a good image density, and had no problems with background stains and blocking. On the other hand, in Comparative Developers 1 and 2 produced in Comparative Examples 1 and 2, a large initial fluctuation of the specific charge was observed, the initial image density was lowered, and the initial background was smeared, and further blocking occurred. It was Further, in the evaluation under high temperature and high humidity, the developer 1 showed a stable specific charge from the initial stage to after printing 100,000 sheets, the image density was good, and there was no problem with background stain and blocking. On the other hand, the comparative developer 1 showed a large initial fluctuation of the specific charge, the initial image density was lowered, and the background stain was gradually generated after printing 1,000 sheets, and more vigorous blocking occurred.

[0070]

According to the method for producing a developer of the present invention, unlike the conventional method, the developer obtained without impairing the productivity of the developer has an improved variation in the specific charge, and the life of the developer is improved. Therefore, the amount of charge can be stably maintained from the time of initial use.
Further, since the developer of the present invention has improved fluidity, it does not cause blocking and can maintain high image quality for a long period of time.

Claims (7)

[Claims] 1. A method for producing a developer, which comprises mixing a carrier and inorganic fine particles to adhere the inorganic fine particles to the surface of the carrier and then electrostatically mixing and adhering the toner to the surface of the carrier. A method for producing a developer, characterized in that the main component of the binder resin is a resin obtained by blending raw material monomers in the same reaction vessel and carrying out addition polymerization and condensation polymerization in parallel. 2. The production method according to claim 1, wherein the addition polymerization is to obtain a vinyl resin by radical polymerization, and the condensation polymerization is to obtain a polyester, polyesteramide or polyamide. 3. The production method according to claim 2, wherein the vinyl-based resin is a styrene-acrylic resin, and polycondensation is to obtain polyester. 4. The average particle size of the carrier is 55 to 160 μm.
The manufacturing method according to claim 1, 2 or 3, wherein m is m. 5. In a developer comprising a carrier and a toner having inorganic fine particles adhered to the surface of the carrier, a binder resin of the toner is blended with a raw material monomer in the same reaction vessel to carry out addition polymerization and condensation. A resin obtained by performing polymerization in parallel, wherein the toner is a carrier 10
A developer containing 1 to 15 parts by weight with respect to 0 parts by weight. 6. The developer according to claim 5, wherein the raw material monomer is a vinyl-based monomer, an alcohol, and a carboxylic acid and / or a derivative thereof. 7. The average particle size of the carrier is 55 to 160 μm.
7. The developer according to claim 5, which is m.