JPH063862A - Magnetic material dispersion type carrier, two-component developer for electrostatic charge image development, production of magnetic material dispersion type carrier and image forming method - Google Patents

Abstract

PURPOSE:To obtain a magnetic material dispersion type carrier which improves spent resistance, shock resistance, decreases deterioration of a toner and stably gives high quality picture images for a long time. CONSTITUTION:This carrier has a core material consisting of dispersion of magnetic fine particles in a binder resin, and the surface of the core material is covered with a resin. The magnetic fine particles dispersed in the resin for the core are treated with a silane coupling agent, and the surface of the core is coated with a resin containing styrene-acryl copolymers. The copolymer has 30-90wt.% monomer ratio in the acryl component, about 20000-500000 weight average mol.wt., and 1.5 to 20 ratio of weight average mol.wt./number average mol.wt.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic substance dispersion type carrier and a method for producing the same. The present invention also relates to a two-component developer for developing an electrostatic charge image having a toner and a carrier. Further, the present invention relates to an image forming method in which a bias voltage is applied in the developing area to develop a latent image with a two-component developer having toner and carrier.

[0002]

2. Description of the Related Art Generally, in an electrostatic recording apparatus using electrophotography, selenium, OPC (organic photoconductor), α-S
A photoconductive substance such as i is used as a photoconductor, the photoconductor is uniformly charged by various means, and then a photoimage is irradiated on the photoconductor surface to form an electrical latent image corresponding to the photoimage. A method is generally used in which a latent image is formed on the surface of a photoconductor and toner is attached to the latent image by a magnetic brush development method or the like to visualize the latent image.

In this developing method, a toner that visualizes the latent image and carrier particles having a magnetic material called a carrier are used, and the carrier is triboelectrically charged to give an appropriate amount of positive or negative electricity. The toner is applied to the toner, and the toner is carried on the surface by the electrostatic attraction of the triboelectric charging.

The developer containing the above toner and carrier is
A developing layer containing a magnet is coated with a predetermined layer thickness by a developer layer thickness regulating member, and is conveyed to a developing area formed between the photoconductor and the developing sleeve by utilizing a magnetic force. It

A certain developing bias voltage is applied between the photoconductor and the developing sleeve, and the toner is developed on the photoconductor in the developing area.

Although there are various characteristics required for the above carrier, suitable charging characteristics, pressure resistance against an applied electric field, impact resistance, abrasion resistance, spent resistance, developability, and productivity are particularly important characteristics. Etc.

For example, when the developer is used for a long period of time,
Toner filming occurs, in which toner that does not contribute to development, called a spent toner, is fused on the surface of the carrier, resulting in deterioration of the developer and accompanying deterioration of the image quality of the developed image.

In general, (1) if the true specific gravity of the carrier is too large, when the developer is made to have a predetermined layer thickness on the sleeve by the developer layer thickness regulating member, or when the developer in the developing device is Since the load applied to the developer during stirring becomes large, (a) toner filming (b) carrier destruction (c) toner deterioration is likely to occur during long-term use of the developer, resulting in development. Deterioration of the developer and accompanying deterioration of the image quality of the developed image are likely to occur. Also, (2)
As the particle size of the carrier increases, the load on the developer also increases as in (1) above.
(C) is likely to occur, resulting in deterioration of the developer. It is also well known that (d) the reproducibility of fine lines in a developed image is poor, that is, the developability is poor.

Therefore, in the carrier in which the above (a) to (c) are likely to occur, it is necessary to replace the developer periodically, and it is uneconomical, so that the load on the developer is reduced. Alternatively, it is necessary to prevent the above (a) to (c) and extend the developer life by improving the impact resistance and the spent resistance of the carrier.

Further, it is necessary to deal with the problem of developability (d) described above by reducing the particle size of the carrier.

To solve the above problems (a) to (d), a carrier having a small particle size in which magnetic particles are dispersed in a binder resin, for example, according to a pulverizing method disclosed in JP-A-54-66134. It is also possible to deal with it by using a magnetic substance dispersion type small particle size carrier.

Further, it is also possible to deal with it by a magnetic substance dispersion type small particle size carrier by a polymerization method, which is disclosed in Japanese Patent Laid-Open No. 61-9659.

However, the magnetic substance-dispersed small particle size carrier has a small saturation magnetization with respect to the particle size when a large amount of the magnetic substance is not contained in the carrier particles, and (e) the photoconductor during development. There is a problem that the carrier adheres to the upper part, and it is necessary to replenish the developer or have a mechanism for collecting the adhered carrier in the image forming apparatus, which is a drastic measure for extending the life of the developer. It has the drawback that it cannot be.

Further, in the above-mentioned magnetic substance-dispersed small particle size carrier, when a large amount of the magnetic substance is contained, the impact resistance becomes weak because the amount of the magnetic substance increases with respect to the binder resin. In this case, when the developer has a predetermined layer thickness on the sleeve with the developer layer thickness regulating member, the magnetic substance is easily lost from the carrier, and as a result, the developer is easily deteriorated. However, there is a drawback that it cannot be a drastic measure for extending the life of the developer.

When a large amount of the magnetic material is contained in the magnetic material-dispersed small particle size carrier, the specific resistance of the carrier is lowered because the amount of the magnetic material having a low specific resistance is increased. (F) It also has a drawback that image defects are likely to occur due to leakage of a bias voltage applied during development.

Therefore, even the above-mentioned magnetic substance-dispersed small particle size carrier with increased amount of magnetic substance has a drawback that it cannot be a drastic measure for improving the developing property and extending the life of the developer. There is.

On the other hand, it is possible to deal with this by the technique of coating the carrier with a resin, which is disclosed in Japanese Patent Laid-Open No. 58-21750. According to the carrier coated with the above resin, the spent resistance, impact resistance,
The withstand voltage with respect to the applied voltage can be improved. Further, since the charging characteristic of the toner can be controlled by the charging characteristic of the resin to be coated, it is possible to impart a desired charging charge to the toner by selecting the resin to be coated.

However, also in the above resin-coated carrier, when the amount of coating resin is large and the specific resistance of the carrier is high, the charge amount of the toner in a low humidity environment becomes large.
The so-called toner charge-up phenomenon easily occurs,
Further, when the amount of the coating resin is small, there is a problem that it is difficult to control the amount of coating, as the specific resistance of the carrier becomes too low, and an image defect is likely to occur due to leakage of the developing bias voltage.

Further, depending on the coating resin, even if the resistivity of the carrier coated with the resin is considered to be the proper resistivity for measurement, image defects are likely to occur due to leakage of the developing bias voltage, or under a low humidity environment. In some cases, the charge-up phenomenon of (3) easily occurs, and the carrier coated with the above resin also has a problem that its control is difficult when the developability is taken into consideration.

[0020]

As described above, considering the above-mentioned required characteristics of the carrier, the conventionally used carrier still has a problem to be improved, and further improvement is desired.

In particular, in a magnetic substance dispersion type carrier in which magnetic particles are dispersed in a binder resin and the surface is covered with a resin, (1) Spent resistance (2) Impact resistance (prevention of carrier destruction) ) (3) Prevention of toner deterioration (4) Developability (5) Prevention of carrier adhesion on photoconductor (6) Control of carrier resistance (7) Carrier with further improved stabilization of toner chargeability is desired. ing.

Therefore, the main object of the present invention is to solve the above-mentioned problems of the magnetic substance-dispersed carrier having the surface coated with a resin, and as a result, it is unnecessary to replenish the carrier during running. It is to provide a magnetic substance-dispersed carrier excellent in developability and developer life by stabilizing the chargeability of the toner during running and when humidity changes.

More specifically, in the magnetic substance dispersion type carrier in which the surface of the core material containing the magnetic particles and the binder resin as described above is coated with the resin, the impact resistance, resistance value and imparting of charge to the toner of the carrier are obtained. It is an object of the present invention to provide a magnetic material-dispersed carrier which is excellent in developability and developer life by improving the stability by the characteristics of the magnetic material used for the core material and the characteristics of the resin to be coated.

Another object of the present invention is to provide a method of manufacturing a magnetic substance dispersion type carrier which can solve the above problems.

Another object of the present invention is to provide an image forming method in which a current leak or carrier adherence to a photoreceptor is reduced when a latent image is developed by applying a bias voltage to a developing area.

[0026]

Means and Actions for Solving the Problems Present Invention (1)
Is a magnetic material dispersion type carrier having a core material in which magnetic fine particles are dispersed in a binder resin, and the surface of the core material is coated with a resin, and the core material is dispersed in the binder resin of the core material. The magnetic fine particles are treated with a silane coupling agent, and the resin coating the surface of the core material contains a styrene-acrylic copolymer, and the monomer ratio of the acrylic component in the copolymer is 30 to 30. 90% by weight,
The weight average molecular weight of the copolymer is about 20,000 to 5,000.
00, and the weight average molecular weight / number average molecular weight is 1.5.
It is a magnetic substance dispersion | distribution type | mold carrier characterized by being -20.

The present invention (2) is a magnetic substance-dispersed carrier having a core material in which magnetic fine particles are dispersed in a binder resin, and the surface of the core material is coated with a resin. Magnetic fine particles dispersed in the binder resin are treated with a titanium coupling agent, and the resin coating the surface of the core material contains a styrene-acrylic copolymer, The monomer ratio of the acrylic component in the coalescence is 30 to 90% by weight, the weight average molecular weight of the copolymer is about 20,000 to 500,000, and the weight average molecular weight / number average molecular weight is 1.5 to 20. It is a magnetic substance dispersion type carrier.

The present invention (3) is a magnetic substance-dispersed carrier having a core material in which magnetic fine particles are dispersed in a binder resin, and the surface of the core material is coated with a resin. The magnetic fine particles dispersed in the binder resin are treated with a titanium coupling agent, and the resin coating the surface of the core material contains a styrene-acrylic copolymer and a fluorine-containing resin. The monomer ratio of the acrylic component in the styrene-acrylic copolymer is 30 to 90% by weight, and the weight average molecular weight is about 200.
The weight average molecular weight / number average molecular weight is 1.5 to 20, and the mixing ratio of the fluorinated resin to the styrene-acrylic copolymer is:
In a weight ratio (weight of the fluororesin: weight of the copolymer),
The magnetic substance-dispersed carrier is characterized by having a ratio of 5:95 to 95: 5.

The present invention (4) is a magnetic material dispersion type carrier having a core material in which magnetic fine particles are dispersed in a binder resin, and the surface of the core material is coated with a resin. Magnetic fine particles dispersed in the binder resin are treated with a titanium-based coupling agent, and the resin coating the surface of the core material contains a vinyl-based copolymer having a hydroxyl value of 1 to 100 and A magnetic material-dispersed carrier containing a fluororesin.

The present invention is also a two-component developer for developing an electrostatic charge image, which comprises the magnetic substance-dispersed carrier of the present invention (1 to 4) and a toner.

The present invention further provides a carrier coating solution containing the resin material and a solvent for dispersing or dissolving the resin material in the method for producing a magnetic substance-dispersed carrier according to the present invention (1 to 4). A method for producing a magnetic material-dispersed carrier, which comprises coating a core material obtained by dispersing magnetic fine particles in a binder resin, drying the core material, and coating the surface of the core material with a resin.

Further, according to the present invention, the latent image formed on the photoconductor is developed by applying a bias voltage in the developing region with the above-mentioned two-component developer for electrostatic image development. Is.

When the magnetic substance-dispersed carrier having the above-mentioned structure is used, the present inventors have improved impact resistance, specific resistance, and stability of imparting charge to toner. In addition, they found that the magnetic substance-dispersed carrier was excellent in developability and developer life, and completed the present invention.

Although details of the improvement of various properties of the carrier are not clear, dispersion of the core material in the binder resin which is made lipophilic by treating the magnetic material with a silane coupling agent or a titanium coupling agent. Property is improved, a uniform dispersion state is achieved, and impact resistance as a carrier is increased.
Furthermore, since the surface of the magnetic body subjected to this treatment has a higher specific resistance than that of the untreated state, it is presumed that leakage will be less likely to occur even in the developing method in which a bias voltage is applied.

Further, in the magnetic substance-dispersed carrier of the present invention, the wettability between the lipophilic magnetic substance and the coating resin is good, so that the surface of the core material can be uniformly coated with the resin, and It is presumed that the impact resistance, the resistance value, and the stability of imparting charge to the toner are further improved.

That is, in the carrier, if the wettability between the magnetic material forming the core material and the binder resin is poor,
The dispersed state of the magnetic material becomes non-uniform, and pulverization is likely to occur via the aggregated magnetic material site or from the interface between the magnetic material and the binder resin, and the durability tends to be poor. Similarly, in the carrier, if the wettability between the magnetic material forming the core material and the coating resin is poor, uniform coating tends to be difficult. Also, if the coating on the core material is non-uniform, even if the surface resistance looks appropriate from a macro standpoint, if the carrier does not have microscopically uniform resistance, charging in a low humidity environment It is considered that there is a problem that an up phenomenon is likely to occur, or an image defect due to a leak of the developing bias voltage is likely to occur. Therefore, it is considered that these characteristics can be improved in the present invention by adopting the above configuration.

Further, the vinyl-based copolymer having a hydroxyl value of 1 to 100 used as the coating resin for the core material in the present invention (4) is excellent in binding property and originally excellent in releasability. It is considered that the spent resistance of the carrier is improved due to the outstanding effect of exposing the fluororesin on the surface of the carrier coating by mixing it with the fluororesin.

Next, as the styrene-acrylic copolymer which can be used for the coating resin of the carrier core material of the present invention (1 to 3), a copolymer of a styrene derivative and an acrylate ester and a styrene derivative can be used. And a methacrylic acid ester copolymer. The following compounds can be mentioned as specific examples of the monomers constituting these styrene-acrylic copolymers. That is, as the styrene derivative, styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-phenylstyrene, p-ethylstyrene, 2,4-dimethylstyrene,
pn-butyl styrene, p-tert-butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene, p -Methoxystyrene, p-chlorostyrene, 3,4-dichlorostyrene,
Examples thereof include m-nitrostyrene, o-nitrostyrene, p-nitrostyrene and the like.

Examples of acrylates include methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, n-octyl acrylate, dodecyl acrylate, and the like.
2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate and the like can be mentioned.

Further, as the methacrylic acid esters, for example, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate,
Isobutyl methacrylate, n-octyl methacrylate,
Dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate and the like can be mentioned.

In the present invention (1 to 3), it is preferable that the monomer ratio of the acrylic component in the styrene-acrylic copolymer which is the coating resin is 30 to 90% by weight.
If the amount is less than 30% by weight, the coating uniformity sufficient to contribute to the present invention cannot be obtained, and the toner has insufficient charge stability. Also,
When it is more than 90% by weight, uniform coating property is obtained, but the strength against impact resistance is insufficient.

Furthermore, the weight average molecular weight of the above-mentioned copolymer which can be used for the coating resin of the carrier core material of the present invention (1 to 3) is indispensable to be 20,000 to 500,000, and the weight average molecular weight / number average. Molecular weight is 1.5 ~
It is indispensable to be 20. Weight average molecular weight is 200
When it is less than 00, the strength with respect to impact resistance of the carrier cannot be obtained, and when it is more than 500000, the covering property with respect to the carrier core is deteriorated, and the strength of the carrier and further the charging stability become poor. More importantly, at this time, even if the weight average molecular weight is within this range,
The effect of the present invention cannot be obtained unless the weight average molecular weight / number average molecular weight is within the range of 1.5 to 20. When the weight average molecular weight / number average molecular weight is less than 1.5, the coating resin is uniformly coated, but the impact resistance is poor. If the weight average molecular weight / number average molecular weight is larger than 20, the uniformity of the coating on the carrier core is deteriorated, and the strength of the carrier and desired charge stability cannot be obtained.

Further, as the fluorine-containing resin mixed with the above-mentioned styrene-acrylic copolymer which can be used as the coating resin for the carrier core material of the present invention (3), polyvinyl fluoride, polyvinylidene fluoride, Hello fluoropolymers such as polytrifluoroethylene, polytrifluorochloroethylene, polytetrafluoroethylene, polyperfluoropropylene, copolymers of vinylidene fluoride and acrylic monomers, vinylidene fluoride and trifluorochloroethylene, Copolymer of tetrafluoroethylene and hexafluoropropylene, copolymer of vinyl fluoride and vinylidene fluoride, copolymer of vinylidene fluoride and tetrafluoroethylene, vinylidene fluoride and hexafluoro Copolymer with propylene, tetrafluoroethylene and vinylidene fluoride Fluoro terpolymers such as terpolymers of beauty non fluorinated monomers can be mentioned.

The mixing ratio of these fluorine-containing resin and styrene acrylic polymer is preferably 5:95 to 95: 5 by weight ratio (weight of the fluorine-containing resin: weight of the copolymer). When the content is within the above range, desired charge stability can be obtained with both positive and negative polarity developers, but when the content of the fluorine-containing resin is less than 5% by weight, the development showing positive charging characteristics is achieved. When the content of the fluorine-containing resin exceeds 95% by weight, the charge stability of the developer is deteriorated, and on the other hand, the charge stability of the developer exhibiting negative charge characteristics is decreased and the wettability is also reduced. As a result, the uniform coating on the core material becomes difficult.

The hydroxyl group-containing vinyl resin used in the present invention (4) is a copolymer of a hydroxyl group-containing vinyl monomer and another vinyl monomer. As the vinyl monomer having a hydroxyl group, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxybutyl acrylate, 2-hydroxy-3-phenyloxypropyl acrylate,
2-hydroxyethyl methacrylate, 2-methacrylic acid
There are hydroxypropyl, 2-hydroxybutyl methacrylate, 2-hydroxy-3-phenyloxypropyl methacrylate and the like. These monomers are used such that the hydroxyl value of the copolymer is 1 to 100 (KOHmg / g), more preferably 5 to 70 (KOHmg / g), and further preferably 10 to 50 (KOHmg / g). Is good.

When this value is small, the effect of exposing the fluorine-containing resin to the carrier surface, which is a feature of the coating resin in the present invention (4), is insufficient and the charge imparting ability of the carrier is lowered. On the other hand, when the hydroxyl value is more than 100, the hygroscopicity is enhanced and the charging stability under high temperature and high humidity is lost.

Other vinyl monomers copolymerized with these hydroxyl group-containing vinyl monomers include styrene, α-methylstyrene, p-methylstyrene and p-methylstyrene.
Styrene derivatives such as -t-butylstyrene and p-chlorostyrene; methyl methacrylate, ethyl methacrylate,
Propyl methacrylate, butyl methacrylate, pentyl methacrylate, hexyl methacrylate, heptyl methacrylate, octyl methacrylate, nonyl methacrylate,
Decyl methacrylate, undecyl methacrylate, dodecyl methacrylate, glycidyl methacrylate, methoxyethyl methacrylate, propoxyethyl methacrylate, butoxyethyl methacrylate, benzyl methacrylate, cyclohexyl methacrylate, methyl acrylate, ethyl acrylate, propyl acrylate Butyl acrylate,
Examples thereof include pentyl acrylate, hexyl acrylate, heptyl acrylate, octyl acrylate, nonyl acrylate, decyl acrylate, vinyl monomers and the like.

Among these other vinyl monomers, the vinyl monomer having one vinyl group in one molecule is preferably styrene, styrene derivative, methacrylic acid ester, acrylic acid ester, etc., and particularly preferably 1 to 5 for the alkyl group.
Alkyl esters of methacrylic acid or acrylic acid having 4 carbon atoms are preferred.

Among these vinyl monomers, the vinyl monomer having a hydroxyl group is used so that the copolymer has a hydroxyl value of 1 to 100 (KOHmg / g). These vinyl monomers are copolymerized by methods such as suspension polymerization method, emulsion polymerization method and solution polymerization method. These copolymers have a weight average molecular weight of 10,000 to 70,
Those of 000 are preferred. Weight average molecular weight is 10,
If it is less than 000, the impact resistance tends to be insufficient, and 70,
If it exceeds 000, it becomes difficult to coat the carrier core material and aggregates are formed, which is not preferable. Further, this copolymer may be melamine aldehyde crosslinked or isocyanate crosslinked. In addition, in this invention (4), a hydroxyl value says the value measured based on JIS-K0070.

On the other hand, as the fluorine-containing resin mixed with the vinyl resin containing a hydroxyl group, polyvinyl fluoride,
Perfluoropolymer such as polyvinylidene fluoride, polytrifluoroethylene, polytrifluorochloroethylene, polytetrafluoroethylene, polyperfluoropropylene, copolymer of vinylidene fluoride and acrylic monomer, vinylidene fluoride Copolymer with trifluorochloroethylene, Copolymer with tetrafluoroethylene and hexafluoropropylene, Copolymer with vinyl fluoride and vinylidene fluoride, Copolymer with vinylidene fluoride and tetrafluoroethylene, Fluorine Fluoroterpolymers such as copolymers of vinylidene fluoride and hexafluoropropylene, terpolymers of tetrafluoroethylene and vinylidene fluoride, and non-fluorinated monomers are preferably used.

The mixing ratio of the fluorine-containing resin and the vinyl resin having a hydroxyl group is, specifically, the ratio (weight ratio) of the fluorine-containing resin and the vinyl resin having a hydroxyl group is from 5:95. 95: 5, more preferably 1
0:90 to 90:10 is good. If the content of the fluorine-containing resin is less than 5% by weight, the exposed amount of the fluorine-containing resin in the uniform resin coating layer tends to be insufficient, while if the content of the fluorine-containing resin exceeds 95% by weight. Since the amount of the vinyl resin having a hydroxyl group is small, the adhesiveness of the resin coating layer to the core material tends to decrease.

In the present invention (3, 4), the weight average molecular weight of the fluororesin is preferably 50,000-4.
0,000, more preferably 100,000-25
10,000 is good. If it is less than 50,000, the abrasion resistance tends to be insufficient, and if it exceeds 400,000, uniform coating on the carrier material becomes difficult.

In the present invention, the molecular weight and molecular weight distribution of the coating resin which can be used as the coating resin for the carrier core material, and the molecular weight of the fluorine-containing resin are those of monodisperse standard by GPC (gel permeation chromatography). The value obtained by observing a calibration curve obtained by using polystyrene. The measurement conditions are shown below.

Equipment: GPC-150C (Waters) Column: Shoredex KF 7 stations (Showa Denko) Temperature: 40 ° C Solvent: THF (tetrahydrofuran) Flow rate: 1.0 ml / min Test material: 0. Injecting 0.4 ml of a 15% sample In the present invention, as the resin used as the binder resin constituting the carrier core material, all resins obtained by polymerizing vinyl monomers can be mentioned. Examples of the vinyl-based monomer here include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-phenylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, pn-butylstyrene. , P-tert-
Butyl styrene, pn-hexyl styrene, pn-
Octyl styrene, pn-nonyl styrene, pn-
Decylstyrene, pn-dodecylstyrene, p-methoxystyrene, p-chlorostyrene, 3,4-dichlorostyrene, m-nitrostyrene, o-nitrostyrene,
Styrene derivatives such as p-nitrostyrene, ethylene,
Ethylene and unsaturated monoolefins such as propylene, butylene and isobutylene; unsaturated diolefins such as butadiene and isoprene; vinyl halides such as vinyl chloride, vinylidene chloride, vinyl bromide and vinyl fluoride; vinyl acetate, propion Vinyl esters such as vinyl acrylate and vinyl benzoate; methacrylic acid and methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, methacrylic acid- Α-Methylene aliphatic monocarboxylic acid esters such as 2-ethylhexyl, stearyl methacrylate, phenyl methacrylate; acrylic acid and methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate Acrylic esters such as propyl acrylate, n-octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate; maleic acid, maleic acid half ester; vinyl methyl Vinyl ethers such as ether, vinyl ethyl ether and vinyl isobutyl ether; vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone and methyl isopropenyl ketone; N-vinyl pyrrole, N-vinyl carbazole, N-vinyl indole,
N-vinyl compounds such as N-vinylpyrrolidone; vinylnaphthalenes; acrylonitrile, methacrylonitrile,
Examples thereof include acrylic acid or methacrylic acid derivatives such as acrylamide; acrolein, and the like, and one of these or two or more of them is used for polymerization.

In addition to resins obtained by polymerizing vinyl monomers, non-vinyl condensation resins such as polyester resins, epoxy resins, phenol resins, urea resins, polyurethane resins, polyimide resins, cellulose resins and polyether resins or the like. And a mixture of the above vinyl-based resin can be used.

The magnetic material used for the magnetic fine particles constituting the carrier core material in the present invention includes, for example, ferromagnetic metals such as iron, cobalt and nickel, ferrite,
Examples include magnetite, hematite, and other alloys or compounds containing iron, cobalt, nickel, and other ferromagnetism elements. The saturation magnetization of the magnetic fine particles according to the present invention is 60 emu / g under a magnetic field of 10 K Oersted.
The above is characterized. If it is less than 60 emu / g, even if the content of the magnetic fine particles is increased,
There was a tendency that carrier adhesion to the photoconductor was likely to occur. Therefore, it is essential that the saturation magnetization is 60 emu / g or more. The magnetic force is measured by V manufactured by Toei Kogyo Co., Ltd.
SM was used.

The magnetic fine particles preferably have a primary average particle diameter of 2.0 μm or less. If it is larger than 2.0 μm, the surface of the core material is not dense and uniform coating cannot be achieved. Further, the content of the magnetic fine particles according to the present invention with respect to the total amount of carrier must be 30% by weight or more, preferably 50% by weight or more. If it is less than 30% by weight, adhesion to the photoreceptor occurs, and it becomes difficult to control the resistance of the carrier.

Therefore, in the magnetic substance-dispersed carrier of the present invention, it is important not only that it does not adhere to the photosensitive member, but also that it is possible to control the charge amount of the toner appropriately. Is one. In particular, it is a feature that the specific resistance of the carrier can be controlled appropriately so as not to give a so-called charge-up phenomenon, that is, to give excessive charging to the toner under a low humidity. Therefore, in the carrier of the present invention, as described above, The particle size, specific resistance and content of the magnetic fine particles are essential.

Next, the structure of the present invention will be described in detail.

In the present invention (1), as the silane coupling agent used as the treating agent for the magnetic substance, known ones (for example, those conventionally used for surface modification of silica and glass) are used without particular limitation. For example, γ- (2-aminoethyl) aminopropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, methyltrimethoxysilane, methyltriethoxysilane,
γ-chloropropylmethyldimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, stearyltrimethoxysilane, diphenyldiethoxysilane, etc. can be used.

According to the knowledge of the present inventors, the dispersibility of the magnetic substance in the binder resin in the core material depends on the nature of the functional group of the treating agent such as the coupling agent used for treating the magnetic substance. It is important to use a treating agent having a functional group having too strong hydrophilicity, which makes it difficult for the treated magnetic material to be uniformly dispersed, and also causes friction of the carrier based on the nature of the functional group of the treating agent. It is not preferable because the charging property, especially the charging property when the environment changes, changes.

From this point of view, in the present invention (1), the silane coupling agent is represented by the following general formula (I).
It is preferable to use a silane compound represented by

[0063]

[Chemical 1] In the above general formula (I), X is an alkyl group (preferably having a carbon number of 1 to 30) or an alkenyl group (preferably,
C1-30) or a phenyl group is shown, but these may be substituted with a mercapto group, a chloro group or an acyloxy group. The substitution position of the substituent such as the mercapto group in X may be in the middle of the carbon chain, but is preferably at the terminal.

R ¹ is an alkyl group (preferably having 1 carbon atom)
~ 30) or an acetyl group. This R ¹ is -Si
It is sufficient that (OR ¹ ) _n is a group which gives a silanol group by hydrolysis. R ² represents a lower alkyl group having 4 or less carbon atoms such as a methyl group and an ethyl group. m is 1 or 2
, N is an integer of 2 or 3, and 3 ≦ m + n ≦ 4
It has a function of.

These silane compounds (1) may be synthesized by a generally known synthesis method, or a commercially available silane coupling agent may be used as it is.

More specifically, the silane coupling agent (A) represented by the general formula (I) preferably used in the present invention is, for example, γ-methacryloxypropyltrimethoxysilane or γ-mercaptopropyltrimethoxysilane. Silane, methyltrimethoxysilane, methyltriethoxysilane, vinyltriacetoxysilane, γ-chloropropyltrimethoxysilane, vinyltrimethoxysilane, γ-chloropropylmethyldimethoxysilane,
γ-mercaptopropylmethyldimethoxysilane, stearyltrimethoxysilane, diphenyldiethoxysilane and the like can be mentioned.

In the present invention (1), the silane coupling agent as described above is preferably 0.1 to 10 parts (more preferably 0.1% to 100 parts) of (untreated) magnetic material.
5 to 5 parts) are used.

The above-mentioned amount of this coupling agent used is 0.1
If the amount is less than 10 parts, the effect due to the use of the coupling agent is not recognized, while if the amount is more than 10 parts, a coupling agent that does not participate in the reaction with the magnetic substance is likely to be produced.
Not preferable.

The above-mentioned coupling agent may be used as a combination of two or more kinds of silane coupling agents, if necessary.

Next, the general formula of a typical titanium-based coupling agent which is preferably used as a treating agent for a magnetic material in the present invention (2-4) is shown below.

[0071]

[Chemical 2] Among the titanium-based coupling agents represented by the above general formula, more specific compounds include the following.

[0072]

[Chemical 3]

[0073]

[Chemical 4] The treatment amount of the titanium-based coupling agent with respect to the magnetic substance varies depending on the particle size of the magnetic substance, the surface structure, etc.
0.5 to 10 parts, more preferably 0.5 to 00 parts
It is preferable to use ~ 5 parts. If the treatment amount of the above titanium-based coupling agent is less than 0.5 part, there is no effect on the dispersibility of the magnetic substance, and if it exceeds 10 parts, a large amount of free coupling agent that does not bind to the magnetic substance is generated. Is not preferable.

The above-mentioned coupling agents may be used in combination of two or more if necessary.

The average particle size of the carrier particles of the present invention is 10 to 10.
It is preferably used in the range of 60 μm. If the carrier particle size is less than 10 μm, the carrier tends to adhere to the photoconductor, and if it exceeds 60 μm, the share of the developer in the developing device increases, and the developer deteriorates, especially the toner particles It tends to cause peeling of the external additive and change in shape. Furthermore, when the particle size is large, the specific surface area is small, so the amount of toner that can be held in the developer is small, and the image lacks fineness. The particle size of the carrier used in the present invention is indicated by the maximum chord length in the horizontal direction, and the measuring method is 500 or more carriers randomly selected by a microscopic method, and the diameter is measured to obtain the carrier particle size of the present invention. .

The true specific gravity of the carrier of the present invention is 1.5 to 5.
A range of 0 is preferred. More preferably 1.5 to 4.5
Is. If the true specific gravity exceeds 5.0, the load on the developer in the developing device increases, which is not preferable from the viewpoint of deterioration of the developer. If the true specific gravity is less than 1.5, it is practically impossible to obtain a magnetic force sufficient to suppress carrier adhesion to the photoconductor. The true specific gravity of the carrier used in the present invention was Trudencer (manufactured by Seishin Enterprise Co., Ltd.).

The specific resistance of the carrier used in the present invention is 10 ⁷
A range of -10 ¹⁴ Ω · cm is suitable. 10 ⁷ Ω · cm
When the amount is less than the above, a current leaks from the sleeve to the surface of the photoconductor in the developing area in the developing method in which a bias voltage is applied, and as a result, a good image cannot be obtained. Also 10 ¹⁴ Ω
・ If it exceeds cm, a charge-up phenomenon is caused under a low humidity condition, which causes image deterioration such as density density, transfer failure, and fog.

In the present invention, the measuring method as shown in FIG. 1 was used for measuring the specific resistance. That is, cell A
Is filled with a carrier, electrodes 1 and 2 are arranged so as to be in contact with the filled carrier, a voltage is applied between the electrodes, and a current flowing at that time is measured to obtain a specific resistance ρ (Ω · c
The method of determining m) was used. In the above measuring method,
Since the carrier is a powder, the filling rate may change and the specific resistance may change accordingly, which requires attention. The measurement conditions of the specific resistance in the present invention were: contact area S between the filled carrier and the electrode S = about 2.3 cm ² , thickness = about 1 mm, load 275 g on the upper electrode 2, and applied voltage 100V.

From the viewpoint that the specific resistance of the carrier of the present invention is within the above range, the specific resistance can be easily improved by coating a low resistance core material containing magnetic fine particles with the coating resin of the present invention. It is an advantage of the present invention that it can be controlled to. Further, it is an advantage of the present invention that the specific resistance can be controlled by making the coating structure a uniform coating. That is, the surface exposed state of the magnetic fine particles in the core material, and the coating state of the coating resin are closely related to the characteristics of the carrier. For example, even if the resistance is the same in measurement, the part where the resistance is partially low as the carrier is If present, the image tends to be disturbed. Therefore, in order to obtain good developability, it is necessary to keep the resistance of each part of the carrier surface substantially the same by uniform resin coating, which is also a feature of the present invention.

The sphericity of the carrier in the present invention (long axis /
The minor axis) is preferably 2 or less. When the sphericity of the carrier of the present invention exceeds 2, the effect of reducing the share of the developer and the effect of improving the fluidity of the developer tend to be reduced. Therefore, the sphericity is preferably 2 or less in order to impair the effects of preventing the deterioration of the developer and improving the developing characteristics that can be achieved by the carrier in the present invention.

As means for achieving the sphericity of 2 or less in the carrier of the present invention, there is a method of heating the core material to heat-melt the surface to make it spherical, or a method of making it mechanically spherical. Alternatively, the core material may be produced by adding magnetic fine particles, a polymerization initiator, a suspension stabilizer, etc. in a monomer solution of a binder resin used for the core material, and dispersing them, and then granulating and polymerizing the core material. If a usual suspension polymerization method for obtaining a material is used, it is possible to achieve a sphericity of 2 or less for the carrier without treating the core material.

Next, the method of manufacturing the carrier in the present invention will be described.

The method for producing a carrier of the present invention comprises two steps of producing a core material and then coating with a resin.

First, as a method for producing the core material, the binder resin and the magnetic fine particles are mixed in a desired amount ratio, and, for example,
A method of kneading at a suitable temperature using a heating and melting mixer such as a three-roll or an extruder, cooling and then pulverizing and classifying, or a method in which the binder resin is dissolved in a soluble solvent After mixing the fine particles into a slurry, granulating and drying using a spray dryer, or magnetic fine particles, polymerization initiator, suspension stabilizer, etc. in the monomer solution of the binder resin for the core material. There is a suspension polymerization method in which granulation polymerization is carried out after adding and dispersing. In particular,
According to the above-mentioned polymerization method, it is not only easy to control the sphericity to 2 or less, but also the magnetic fine particles are uniformly dispersed in each part of the core material surface, and at least one of the magnetic fine particle surfaces is Since it is possible to control the part to be substantially exposed to the surface of the core material, it is a more preferable method for producing the core material for obtaining the effect of the present invention.

Next, as a method for coating the core material with a resin,
Considering that the core material is made of resin, a treatment method in which the coating resin is rapidly coated so that the core materials do not adhere to each other is desirable, and the selection of the solvent that dissolves the coating resin and the treatment temperature, time, etc. A treatment method in which coating and drying are simultaneously carried out in such a manner that the conditions are sufficiently controlled and the core material is always allowed to flow is preferably used. In addition,
The amount of coating resin varies depending on the true specific gravity of the core material, and when the true specific gravity of the carrier is X, the optimum value of the coating resin amount must satisfy the following relational expression.

1 / 2X ≦ amount of coating resin ≦ 50 / X (% by weight) More preferably, 1 / X ≦ amount of coating resin ≦ 25 / X (% by weight).

That is, if the coating resin amount is less than 1/2 × wt%, it is difficult to coat the surface of the core material uniformly because the coating resin amount is small, and even if coating is possible, a carrier with sufficient strength is obtained. Cannot happen. On the other hand, if it exceeds 50 / X% by weight, the amount of the coating resin is too large, which makes it difficult to coat uniformly, and the surplus coating resin tends to exist alone in the carrier. Therefore, not only is it impossible to control the resistance to an optimum value, which is a feature of the present invention, but also the developability tends to deteriorate due to the excess coating resin in the developer being attached to the photoreceptor.

The two-component developer for developing an electrostatic image of the present invention contains 10 to 1000 parts by weight, preferably 30 to 50 parts by weight of the above magnetic substance-dispersed carrier with respect to 10 parts by weight of the toner.
It is preferable to use 0 parts by weight as a mixture.

The toner according to the present invention has a weight average particle diameter of 1 to 20 μm, preferably 4 to 13 μm, and more preferably 4 to 10 μm.

The weight average particle diameter of the toner can be measured by various methods, but in the present invention, it is measured using a Coulter counter.

As a measuring device, a Coulter counter T
Interface (made by Nikkaki) and CX that output number distribution and volume distribution using A-II type (made by Coulter)
-1 Connect a personal computer (made by Canon),
As the electrolytic solution, a 1% NaCl aqueous solution is prepared using first grade sodium chloride. As a measuring method, the electrolytic aqueous solution 100 to
To 150 ml, 0.1 to 5 ml of a surfactant, preferably an alkylbenzene sulfonate, is added as a dispersant, and 2 to 20 mg of a measurement sample is further added. The electrolytic solution in which the sample is suspended is subjected to a dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes, and a particle size distribution of particles of 2 to 40 μm based on the number is used with the Coulter Counter TAII type using an aperture of 100 μm. Was measured, and the value relating to the present invention was then determined.

As the binder resin used in the toner according to the present invention, the following binder resin for toner can be used when a heating and pressure roller fixing device having an oil coating device is used.

For example, homopolymers of styrene and its substitution products such as polystyrene, poly-p-chlorostyrene and polyvinyltoluene; styrene-p-chlorostyrene copolymers, styrene-vinyltoluene copolymers, styrene-
Vinyl naphthalene copolymer, styrene-acrylic acid ester copolymer, styrene-methacrylic acid ester copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-
Styrene such as vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer -Based copolymer; polyvinyl chloride, phenol resin, natural modified phenol resin, natural resin modified maleic acid resin, acrylic resin, methacrylic resin, polyvinyl acetate, silicone resin, polyester resin, polyurethane, polyamide resin, furan resin, epoxy resin , Xylene resin, polyvinyl butyral, terpene resin, coumarone indene resin, petroleum resin can be used.

In the heating and pressure roller fixing system in which oil is hardly applied, the offset phenomenon in which a part of the toner image on the toner image support member is transferred to the roller and the adhesion of the toner to the toner image support member are important. It's a problem.
Toners that fix with less heat energy usually tend to be blocked or caked during storage or in a developing device, and therefore these problems must be taken into consideration at the same time. Therefore, the selection of the binder resin is more important when the heating and pressure roller fixing method in which the oil is hardly applied is used in the present invention. Preferred binder resins include cross-linked styrenic copolymers or cross-linked polyesters.

Examples of the comonomer for the styrene monomer of the styrene copolymer include acrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate,
Double bond such as dodecyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, phenyl acrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate, octyl methacrylate, acrylonitrile, methacrylonitrile, acrylamide A dicarboxylic acid having a double bond such as maleic acid, butyl maleate, methyl maleate, and dimethyl maleate; and a substituted product thereof; for example, vinyl chloride, vinyl acetate, vinyl benzoate Vinyl esters such as ethylene; propylene; butylene; ethylene-based olefins such as vinyl methyl ketone; vinyl hexyl ketone; vinyl ketones such as vinyl methyl ether; Ether, such as vinyl ethers vinyl isobutyl ether; such vinyl monomers are used alone or two or more.

As the cross-linking agent, a compound having two or more polymerizable double bonds is mainly used, and examples thereof include aromatic divinyl compounds such as divinylbenzene and divinylnaphthalene; for example, ethylene glycol diacrylate and ethylene glycol diethylene. Methacrylate, 1,3
A double bond such as butanediol dimethacrylate
Carboxylic acid ester having one; divinylaniline, divinyl ether, divinyl sulfide, divinylsulfone divinyl compound; and a compound having three or more vinyl groups; used alone or as a mixture. The crosslinking agent is 0.01 to 10% by weight based on the binder resin.
It is preferable to use a binder resin (preferably 0.05 to 5% by weight) at the time of synthesis in terms of offset resistance and fixing property.

When the pressure-fixing method is used, a binder resin for pressure-fixing toner can be used, and examples thereof include polyethylene, polypropylene, polymethylene, polyurethane elastomer, ethylene-ethyl acrylate copolymer,
There are ethylene-vinyl acetate copolymers, ionomer resins, styrene-butadiene copolymers, styrene-isoprene copolymers, linear saturated polyesters, and paraffins.

In the toner according to the present invention, a charge control agent is blended with toner particles (internal addition) or mixed with toner particles (external addition).
It is preferable to use. The charge control agent makes it possible to control the optimum charge amount according to the developing system, and particularly in the present invention, it is possible to further stabilize the balance between the particle size distribution and the charge. As described above, it is possible to further clarify the function separation and the mutual complementarity for improving the image quality depending on the particle size range. As the positive charge control agent, a modified product of nigrosine and a fatty acid metal salt; tributylbenzylammonium-1-hydroxy-4-naphthosulfonate,
Quaternary ammonium salts such as tetrabutylammonium tetrafluoroborate; diorganotin oxides such as dibutyltin oxide, dioctyltin oxide, dicyclohexyltin oxide; dibutyltin borate, dioctyltin borate, dicyclohexyltin borate used alone or in combination of two or more be able to. Among these, charge control agents such as nigrosine and quaternary ammonium salts are particularly preferably used.

General formula

[0100]

[Chemical 5] A homopolymer of a monomer represented by: or a copolymer with a polymerizable monomer such as styrene, acrylic acid ester and methacrylic acid ester as described above can be used as a positive charge control agent. In this case, these charge control agents also function as (all or part of) the binder resin.

As the negative charge control agent that can be used in the present invention, for example, organometallic complexes and chelate compounds are effective, and examples thereof include aluminum acetylacetonate, iron (II) acetylacetonate, and 3,5- J-t
There is chromium ert-butyl salicylate. Acetylacetone metal complexes (including monoalkyl-substituted and dialkyl-substituted), salicylic acid-based metal complexes (including monoalkyl-substituted and dialkyl-substituted) and salts are preferable, and salicylic acid-based metal complexes or salicylic acid-based metal salts are particularly preferable. Is preferred.

The charge control agent (which does not act as a binder resin) described above is preferably used in the form of fine particles. In this case, the number average particle size of this charge control agent is
Specifically, it is preferably 4 μm or less (further, 3 μm or less).

When internally added to the toner, such a charge control agent is preferably used in an amount of 0.1 to 20 parts by weight (more preferably 0.2 to 10 parts by weight) with respect to 100 parts by weight of the binder resin.

Fine silica powder is preferably added to the toner according to the present invention. When the toner and the silica fine powder are combined, the wear is remarkably reduced by the presence of the silica fine powder between the toner particles and the carrier or the surface of the sleeve. As a result, the life of the toner and carrier or / and the sleeve can be extended, and the stable chargeability can be maintained, so that the two-component developer having a better toner and carrier can be used for a long period of time. It is possible.

Particularly, in the case of a toner having a weight average particle diameter of 10 μm or less, the specific surface area becomes larger than that of a toner having a weight average particle diameter of more than 10 μm, and the toner particles and the carrier are brought into contact with each other for frictional charging. In this case, the number of contact between the surface of the toner particles and the carrier is increased and the abrasion of the toner particles and the contamination of the carrier are more likely to occur than the toner having a weight average particle diameter of more than 10 μm. Addition of the powder makes it possible to obtain a good two-component developer.

As the silica fine powder, silica fine powder produced by a dry method or a wet method can be used, but from the viewpoint of filming resistance and durability, it is preferable to use the silica fine powder by the dry method.

The dry method mentioned here is a method for producing fine silica powder produced by vapor phase oxidation of a silicon halogen compound, for example.

On the other hand, as the method for producing the silica fine powder used in the present invention by the wet method, various conventionally known methods can be applied.

As the silica fine powder referred to herein, anhydrous silicon dioxide (colloidal silica); silicates such as aluminum silicate, sodium silicate, potassium silicate, magnesium silicate and zinc silicate can be applied.

Among the above silica fine powders, those having a specific surface area by nitrogen adsorption of 30 m ² / g or more (particularly 50 to 400 m ² / g) measured by the BET method give good results. The fine silica powder is used in an amount of 0.01 to 8 parts by weight, preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the toner.

When the toner according to the present invention is used as a positively chargeable toner, silica fine powder added for preventing abrasion of the toner and contamination of the surface of the carrier and the sleeve is not negatively chargeable. It is preferable to use the positively chargeable silica fine powder without impairing the charging stability, and when used as the negatively chargeable toner, it is preferable to use the negatively chargeable silica fine powder for the same reason.

Since silica fine powder is generally negatively charged, a method for obtaining positively charged silica fine powder is to use the above-mentioned untreated silica fine powder and at least one nitrogen atom in the side chain. There is a method of treating with a silicone oil having an organo group contained therein, a method of treating with a nitrogen-containing silane coupling agent, or a method of treating with both of them.

In the present invention, the positively chargeable silica is one having a positive triboelectric charge with respect to the iron powder carrier when measured by the blow-off method.

As the silicone oil having a nitrogen atom in the side chain used for treating the silica fine powder, silicone oil having at least a partial structure represented by the following formula can be used.

[0115]

[Chemical 6] (In the formula, R ₁ represents hydrogen, an alkyl group, an aryl group or an alkoxy group, R ₂ represents an alkylene group or a phenylene group, R ₃ and R ₄ represent hydrogen, an alkyl group or an aryl group, and R ₅ Represents a nitrogen-containing heterocycle.) In the above formula, the alkyl group, the aryl group, the alkylene group, and the phenylene group may have an organo group having a nitrogen atom, and within a range that does not impair the charging property, It may have a halogen substituent. The silicone oil is used in an amount of 1 to 50% by weight, preferably 5 to 30% by weight, based on the fine silica powder.

The nitrogen-containing silane coupling agent used in the present invention generally has a structure represented by the following formula.

Rm-Si-Yn (R represents an alkoxy group or halogen, Y represents an amino group or an organo group having at least one nitrogen atom, and m and n are integers of 1 to 3 and m + n. =
It is 4. Examples of the organo group having at least one nitrogen atom include an amino group having an organic group as a substituent, a nitrogen-containing heterocyclic group, or a group having a nitrogen-containing heterocyclic group. As the nitrogen-containing heterocyclic group, there are an unsaturated heterocyclic group and a saturated heterocyclic group, and known ones can be applied. Examples of the unsaturated heterocyclic group include the following.

[0118]

[Chemical 7] Examples of the saturated heterocyclic group include the followings.

[0119]

[Chemical 8] The heterocyclic group used in the present invention is preferably a 5-membered ring or a 6-membered ring in view of stability.

Examples of such treating agents include aminopropyltrimethoxysilane, aminopropyltriethoxysilane, dimethylaminopropyltrimethoxysilane,
Diethylaminopropyltrimethoxysilane, dipropylaminopropyltrimethoxysilane, dibutylaminopropyltrimethoxysilane, monobutylaminopropyltrimethoxysilane, dioctylaminopropyltrimethoxysilane, dibutylaminopropylmonomethoxysilane, dimethylaminophenyltriethoxysilane,
There are trimethoxysilyl-γ-propylphenylamine and trimethoxysilyl-γ-propylbenzylamine. Further, as the nitrogen-containing heterocycle, those having the above-mentioned structure can be used, and examples of such a compound include methoxysilyl-γ-propylpiperidine and trimethoxysilyl-γ.
-Propylmorpholine, trimethoxysilyl-γ-propylimidazole. The silane coupling agent is used in an amount of 1 to 50% by weight, preferably 5 to 30% by weight, based on the fine silica powder.

The applied amount of the treated positive or negative silica fine powder is 0.01 with respect to 100 parts by weight of the toner.
When 8 to 8 parts by weight, the effect is exhibited, and particularly preferably 0.
When added in an amount of 1 to 5 parts by weight, it exhibits positive or negative chargeability with excellent stability. With respect to the addition form, to describe a preferable mode, it is preferable that 0.1 to 3 parts by weight of the treated silica fine powder is adhered to the surface of the toner particle with respect to 100 parts by weight of the toner. The untreated silica fine powder described above can also be used in the same application amount.

The silica fine powder used in the present invention may be treated with a silane coupling agent or a treating agent such as an organic silicon compound for the purpose of hydrophobizing, if necessary, and reacts or physically adsorbs with the silica fine powder. It is treated with the above treatment agent. Examples of such a treating agent include hexamethyldisilazane, trimethylsilane, trimethylchlorosilane, trimethylethoxysilane, dimethyldichlorosilane, methyltrichlorosilane, allyldimethylchlorosilane, allylphenyldichlorosilane, and benzyldimethylchlorosilane, Brommethyldimethylchlorosilane,
α-chloroethyltrichlorosilane, β-chloroethyltrichlorosilane, chloromethyldimethylchlorosilane, triorganosilylmercaptan, trimethylsilylmercaptan, triorganosilylacrylate, vinyldimethylacetoxysilane, dimethylethoxysilane, dimethyldimethoxysilane, diphenyldiethoxysilane , Hexamethyldisiloxane, 1,3-divinyltetramethyldisiloxane, 1,3-diphenyltetramethyldisiloxane, and 2 to 12 siloxane units per molecule, one for each terminally located unit There is a dimethylpolysiloxane containing a hydroxyl group bonded to the addressed Si. These are used alone or in a mixture of two or more. The treating agent is preferably used in an amount of 1 to 40% by weight based on the fine silica powder.

BET specific surface area 5 instead of silica fine powder
Titanium oxide fine powder (TiO ₂ ) of 0 to 400 m ² / g may be used. Further, a mixed powder of silica fine powder and titanium oxide fine powder may be used.

It is also possible to add fine powder of a fluorine-containing polymer (for example, fine powder of polytetrafluoroethylene, polyvinylidene fluoride or tetrafluoroethylene-vinylidene fluoride copolymer) to the toner according to the present invention. Is. Particularly, fine powder of polyvinylidene fluoride is preferable in terms of fluidity and abrasivity. The amount added to the toner is 0.01 to 2.0 wt%, especially 0.02.
~ 1.5 wt% (more preferably 0.02-1.0
wt%) is preferred.

As the colorant, conventionally known dyes and / or pigments can be used. For example, carbon black, phthalocyanine blue, peacock blue,
Permanent red, rake red, rhodamine rake, Hansa yellow, permanent yellow, benzidine yellow, etc. can be used. The content thereof is 0.1 to 20 parts by weight, preferably 0.5 to 20 parts by weight, based on 100 parts by weight of the binder resin, and further 1 to improve the transparency of the OHP film on which the toner image is fixed.
It is preferably 2 parts by weight or less, more preferably 0.5 to 9
Good parts by weight.

The toner according to the present invention contains low-molecular-weight polyethylene, low-molecular-weight polypropylene, microcrystalline wax, and the like for the purpose of improving releasability at the time of heat roll fixing.
Addition of a wax-like substance such as carnauba wax, sazol wax, and paraffin wax in an amount of 0.5 to 5 wt% is one of the preferred embodiments of the present invention.

If desired, other additives may be added to the toner of the present invention.

To prepare the toner according to the present invention, a vinyl-based or non-vinyl-based thermoplastic resin, a pigment or dye as a coloring agent, a charge control agent, and other additives, if necessary, are mixed with a mixer such as a ball mill. After sufficiently mixing with a heating roll, kneader, using a heat kneader such as an extruder, kneading and kneading meat to disperse or dissolve the pigment or dye in the resin to make them compatible with each other, cooling After solidification, pulverization and strict classification can be performed to obtain toner particles. The toner particles can be used as a toner as they are, but if necessary, an external additive such as silica fine powder is added to the obtained toner particles, and the toner particles and the external additive are added using a mixer such as a Henschel mixer. A toner can be obtained by mixing and.

Next, the image forming method according to the present invention will be described with reference to the developing device shown in FIG.

The latent image carrier 11 is an insulating drum for electrostatic recording or α-Se, CdS, ZnO ₂ , OPC, α-Si.
A photosensitive drum or photosensitive belt having a photoconductive insulating material layer such as The latent image carrier 11 is rotated in the direction of arrow a by a driving device (not shown). 22 is a latent image carrier 11
Is a developing sleeve as a developing carrier that is in close proximity to or in contact with, and is made of a non-magnetic material such as aluminum or SUS316. The developing sleeve 22 has a horizontally elongated opening formed in the lower left wall of the developing container 36 in the longitudinal direction of the container so that a substantially right half peripheral surface projects into the container 36, and a substantially left half peripheral surface is exposed to the outside of the container so as to be rotatably supported. It is installed horizontally and is driven to rotate in the direction of arrow b.

Reference numeral 23 is a fixed permanent magnet (magnet) as fixed magnetic field generating means which is inserted into the developing sleeve (developing carrier) 22 and positioned and held in the position and orientation shown in the drawing.
Even when the developing sleeve 22 is rotationally driven, the magnet 23 is fixedly held in the illustrated position and posture. This magnet 2
3 has four magnetic poles, an N-pole magnetic pole 23a, an S-pole magnetic pole 23b, an N-pole magnetic pole 23c, and an S-pole magnetic pole 23d. Magnet 23
May be replaced with an electromagnet instead of the permanent magnet.

Reference numeral 24 designates a base portion fixed to the side wall of the container on the upper edge side of the developer supply device in which the developing sleeve 22 is arranged, and the tip side is projected to the inside of the container 36 beyond the upper edge position of the opening to open the upper edge of the opening. A nonmagnetic blade as a developer regulating member arranged along the length, for example, SUS316 bent into a V-shaped cross section.

Reference numeral 26 is a magnetic carrier limiting member whose upper surface is in contact with the lower surface side of the non-magnetic blade 24 and whose front end surface is the developer guide surface 261. The portion formed by the non-magnetic blade 24, the magnetic carrier limiting member 26, and the like is the restriction portion.

27 is a carrier of the present invention in which a resin coating layer is formed on a core material in which magnetic fine particles are dispersed in a binder resin. 37 is a non-magnetic toner. Reference numeral 40 denotes a seal member for sealing the toner accumulated in the lower portion of the developing container 36, which has elasticity and is bent in the rotation direction of the sleeve 22, and elastically presses the surface side of the sleeve 22. The seal member 40 has an end portion on the downstream side in the sleeve rotation direction in the contact area with the sleeve so as to allow the developer to enter the inside of the container.

Reference numeral 30 denotes a scattering prevention electrode plate for preventing the scattering of the floating developer generated in the developing process by applying a voltage having the same polarity as that of the developer and adhering it to the photoreceptor side.

Reference numeral 60 denotes a toner density detection sensor (not shown)
It is a toner replenishing roller that operates according to the output obtained by. As the sensor, the developer volume detection method,
A piezoelectric element, an inductance change detecting element, an antenna method using alternating bias, and a method for detecting optical density can be used. The non-magnetic toner 37 is replenished by stopping the rotation of the roller. The fresh developer supplied with the toner 37 is mixed and stirred while being conveyed by the screw 61. Therefore, tribo is applied to the replenished toner during this conveyance. 63 is a cut-off plate, which is cut out at both longitudinal ends of the developing device,
At this portion, the fresh developer conveyed by the screw 61 is transferred to the screw 62.

The S magnetic pole 23d is a carrier pole. The collected developer after the development is collected in the container, and the developer in the container is conveyed to the regulation unit.

In the vicinity of 23d, the fresh developer conveyed by the screw 62 provided close to the sleeve and the recovered developer after development are exchanged.

Reference numeral 64 is a conveying screw for equalizing the amount of developer in the axial direction of the developing sleeve.

The distance d between the end of the non-magnetic blade 24 and the surface of the developing sleeve 22 is 100 to 900 μm, preferably 1
It is 50 to 800 μm. If this distance is less than 100 μm, the magnetic particles to be described later are clogged between them and the developer layer is liable to be uneven, and the developer necessary for good development cannot be applied, so that a developed image with a thin density and unevenness is formed. There is a drawback that can only be obtained. d is preferably 400 μm or more in order to prevent uneven coating (so-called blade clogging) due to useless particles mixed in the developer. 9
If it is larger than 00 μm, the amount of the developer applied onto the developing sleeve 22 increases and the predetermined developer layer thickness cannot be regulated, the magnetic particles adhere to the latent image carrier more, and the circulation of the developer described later, There is a drawback that the regulation of development by the developer limiting member 26 is weakened, toner tribo is insufficient, and fogging is likely to occur.

When an imaginary line connecting the center of the developing sleeve 22 and the magnetic pole 23a is L _1, and an imaginary line connecting the center of the developing sleeve 22 and the tip of the non-magnetic blade 24 as a developer regulating member is L ₂ , Let θ ₁ be the angle formed by the virtual line L ₁ and L ₂ .

This angle θ ₁ is -5 ° to 35 °, preferably 0 ° to 25 °. When θ ₁ <−5 °, the thin developer layer formed by the magnetic force, mirroring force, cohesive force, etc. acting on the developer becomes sparse and uneven, and when θ ₁ > 35 °, it is non-magnetic. With the blade, the amount of developer applied increases, and it is difficult to obtain a predetermined amount of developer.

In this magnetic particle layer, the sleeve 22 has an arrow b.
Even if the sleeve 22 is rotationally driven in the direction, the movement becomes slower as the distance from the sleeve surface increases due to the balance between the restraining force based on the magnetic force and gravity and the conveying force in the moving direction of the sleeve 22. Of course, some of them fall under the influence of gravity.

Therefore, by appropriately selecting the positions where the magnetic poles 23a and 23d are arranged and the fluidity and magnetic characteristics of the magnetic carrier 27, the magnetic particle layer is transported in the direction of the magnetic pole 23a as it is closer to the sleeve to form a moving layer. Due to the movement of the magnetic carrier, the sleeve is rotated to be conveyed to the developing area for development.

At this time, it is preferable that the thickness of the developer layer on the developing sleeve 22 is set to be equal to or slightly larger than the facing gap distance e between the developing sleeve 22 and the latent image carrier 11, and an alternating electric field is applied to this gap. . This distance e is 50 to 8
00 μm (more preferably 100 to 700 μm) is preferable.

By applying a developing bias in which a DC electric field is superimposed on the alternating electric field or the alternating electric field between the developing sleeve 22 and the latent image carrier 11 by the bias power source, the toner from the developing sleeve 22 to the latent image holding member 11 is applied. Can be easily moved and a high quality image can be formed.

The alternating electric field as the applied alternating electric field is preferably 2000 Vpp or less, and when the DC electric field is superposed, the DC electric field is preferably applied in the range of 1000 V or less.

[0148]

The present invention will be described below with reference to examples. This does not limit the invention in any way. In addition, all% and parts in the following formulations represent% by weight and parts by weight, and
w represents a weight average molecular weight, and Mn represents a number average molecular weight.

The following Examples 1 to 4 and Comparative Examples 1 to 5 relate to the present invention (1). The physical properties of the carrier used for these are shown in Table 1 and the evaluation results are shown in Table 2. In addition, Examples 5 to 9 and Comparative Examples 6 to 9 are related to the present invention (2). Table 3 shows the physical properties of the carrier used for these and Table 4 shows the evaluation results. Further, Examples 10 to 14 and Comparative Example 1
0 to 14 relate to the present invention (3), and the physical properties of the carrier used for these are shown in Table 5 and the evaluation results are shown in Table 6. Further, Examples 15 to 19 and Comparative Examples 15 to 19 are related to the present invention (4), and Table 7 shows the physical properties of the carrier used for them and Table 8 shows the evaluation results.

Example 1 Silane Coupling Agent (Methyltriethoxysilane) 5
Parts to 500 parts of toluene and stir well. Then 5
While adding 00 parts of magnetite (average particle size 0.24 μm) and heating to 70 ° C., an ultrasonic disperser (10 KHz,
The mixture was stirred at 200 W) for 30 minutes, then left still for 30 minutes, filtered to remove the solvent, and the obtained magnetite was vacuum dried. Using the treated magnetite thus obtained, a core material was prepared as follows. -Styrene 20.3% -Butyl acrylate 10.4% -Treatment magnetite (0.24 μm) 69.3% The above materials were heated in a container at a temperature of 70 ° C. and dissolved to obtain a monomer mixture. While maintaining the temperature at 70 ° C., an initiator 2,2′-azobis- (2,4-dimethylvaleronitrile) was added and dissolved to prepare a monomer composition. This was put into a 2 liter flask containing 1.2 liter of a 1% PVA aqueous solution, and was placed at 4500 at 70 ° C. with a homogenizer.
The composition was granulated by stirring at rpm for 10 minutes. Then, polymerization was performed at 70 ° C. for 10 hours while stirring with a paddle stirrer. After the completion of the polymerization reaction, the reaction product was cooled, and the obtained magnetic substance-dispersed styrene acrylic slurry was washed and filtered.
This was dried to obtain magnetic substance-dispersed resin particles. The true specific gravity of the obtained magnetic substance-dispersed resin particles, that is, the core material is 2.2.
Met.

The surface of the obtained core material was coated with the following resin coating layer.

Styrene-2-ethylhexyl methacrylate (40/60) Mw / Mn = 8.4 Mw = 125000 The above styrene-based copolymer was coated with toluene so that the amount of resin was 0.8% from the above formula. 10% dissolved therein to make a carrier coating solution. This carrier coating solution was applied to the above core material while being dried while being applied by an applicator (supplied by Okada Seiko Co., Ltd .: Spiracoater). The resulting coated magnetic material-dispersed resin carrier is dried at a temperature of 60 ° C. for 1 hour to remove the solvent, and then heated at a temperature of 110 ° C. for 2 hours to coat the core material surface with a resin coating layer. A mold resin carrier was obtained. When the obtained resin-coated magnetic material-dispersed resin carrier was observed with an electron microscope, the core material was uniformly coated with the resin, and the magnetic material particles were exposed substantially uniformly on the coated surface. Was confirmed.

The physical properties of the obtained carrier are summarized in Table 1.

On the other hand, a polyester resin obtained by condensing 100 parts of propoxylated bisphenol and fumaric acid, 5 parts of a phthalocyanine pigment, 4 parts of a chromium complex salt of di-tert-butylsalicylic acid, 4 parts of which were sufficiently premixed with a Henschel mixer. After that, the mixture was melt-kneaded with a three-roll mill three times, cooled, and then coarsely pulverized with a hammer mill to a particle size of about 1 to 2 mm.
Then, it was pulverized by an air jet pulverizer. Further, the finely pulverized product obtained is classified to have a weight average diameter of 1
Negatively chargeable cyan powder (toner) of 2.3 μm
Got

100 parts of the cyan toner and 0.4 part of silica fine powder hydrophobized with hexamethyldisilazane were mixed by a Henschel mixer to prepare a cyan toner having silica fine powder on the toner particle surface.

This cyan toner and the above resin carrier were mixed in an environment of temperature / humidity of N / N (23 ° C./60% RH) so that the toner concentration would be 10% to obtain a developer. 100 g of the obtained developer was put in a 250 cc plastic bottle and shaken with a Turbula mixer for 1 hour. After that, the developer was taken out and observed with an electron microscope. As a result, desorption of the magnetic material from the carrier, peeling of the coating material, and filming by the toner were not observed. Further, neither detachment of the external additive of the toner nor burial was observed.

Further, a cyan toner and the above resin carrier were mixed in an environment of temperature / humidity of L / L (15 ° C./10% RH) so as to have a toner concentration of 8% to obtain a developer. This is a Canon full-color laser copier CLC-
Put in the developing device for 1 and drive with external motor (peripheral speed 300
rpm) for 30 minutes. After this, CLC
-1 was used and an image was output with a development contrast of 300V. As a result, the density of the solid image was sufficient and the reproducibility of the halftone portion was good. The above results are summarized in Table 2.

Comparative Example 1 A core material was prepared in the same manner as in Example 1 except that an untreated magnetite was used, and a resin-coated carrier was subjected to the same tests as in Example 1.

As a result of the shaking test, peeling of the coating resin from the carrier surface and partial toner spent were observed by observation with an electron microscope. In addition, as a result of the image output test, image disturbance, which is considered to be caused by the leak of the applied bias voltage, occurred. In addition, carrier adhesion to the non-image area was observed.

Comparative Example 2 The same test as in Example 1 was conducted using the core material used in Example 1 as a carrier without resin coating.

As a result of the shaking test, toner spent was observed on the carrier surface by observation with an electron microscope.

COMPARATIVE EXAMPLE 3 In place of the core material used in Example 1, 42 μm reduced iron particles were used, and the coating resin used in Example 1 was applied in the same manner as in Example 1 so that the coating amount was 0.8%. Coated. Using this carrier, the same measurements and tests as in Example 1 were performed.

As a result of the shaking test, the carrier did not change from that before shaking, but the burial of the external additive on the toner surface was observed. In addition, as a result of the image output test, the halftone portion was particularly rough.

Comparative Example 4 Instead of the carrier coating solution used in Example 1, the core material used in Example 1 was replaced by styrene-2-ethylhexyl methacrylate (90/1).
0) Mw / Mn = 20.2 Mw = 12000 was used to dissolve 10% in toluene so that the amount of the coating resin was 0.8% to prepare a carrier coating solution.

The above carrier coating solution was applied in the same manner as in Example 1 to obtain a carrier in which the surface of the carrier core material was coated with a resin coating layer. When the obtained resin carrier was observed with an electron microscope, the coating state was not uniform.
Further, the same test as in Example 1 was conducted using this carrier.

As a result of the shaking test, peeling of the coating material was observed, and some detachment of the magnetic material was also observed. further,
As a result of the image output test, image unevenness occurred.

Example 2 Styrene-2-ethylhexyl acrylate 50% (55/45) Copolymer Treated magnetite (same as Example 1) 50% After thoroughly premixing the above materials with a Henschel mixer, The mixture was melt-kneaded at least twice with a three-roll mill, cooled, and coarsely pulverized with a hammer mill to a particle size of about 2 mm. Then, it was finely pulverized to a particle size of 47 μm by an air jet type fine pulverizer. Further, the obtained finely pulverized product was put into MechanoMill MM-10 (manufactured by Okada Seiko Co., Ltd.) and mechanically spheroidized.

The pulverized finely pulverized particles were further classified to obtain a core material. The particle size of the obtained core material was 46 μm.

A coating layer was provided on the surface of the obtained core material in the same manner as in Example 1 to obtain a resin-coated carrier.

The same test as in Example 1 was conducted using this carrier.

As a result, a shaking test was conducted in the same manner as in Example 1.
It was good in the image output test.

Example 3A 3 parts of a silane coupling agent (methylpropyldichlorosilane) is added to 500 parts of xylene, and they are stirred well.
Next, 500 parts of magnetite (average particle size 0.24 μm)
Is added, the mixture is heated to 65 ° C., mixed with a mixer, and then the solvent is removed by vacuum drying. Using the magnetite thus obtained, a core material was prepared as follows. -Ethoxylated bisphenol-fumaric acid-40% Polyester resin obtained by condensing trimellitic acid (50/40/10) -Treatment magnetite (particle diameter 0.24 µm) 60% The same materials as in Example 2 were used. A spherical core material was obtained. The particle size of the particles was 52 μm.

The surface of the obtained core material was coated with the following coating resin in the same manner as in Example 1.

Styrene-butyl acrylate-methyl methacrylate copolymer (50/35/15) Mw / Mn = 8.6 Mw = 120,000 was dissolved in toluene at 5% so that the coating resin amount was 1.2%. The above resin fine particles were coated with the above carrier coating solution in the same manner as in Example 1 to obtain a magnetic substance-dispersed resin carrier. Further, when the same test as in Example 1 was conducted, good results were obtained as in Example 1.

Example 3B A core material was produced in the same manner as in Example 3A except that the amount of magnetite in Example 3A was changed to 38% (the rest being polyester resin). 5% of the coating resin used in Example 3A was dissolved in toluene so that the coating resin amount was 1.2%, and coating was performed in the same manner as in Example 3A as a coating solution to obtain a magnetic substance-dispersed resin carrier. Obtained. Using this carrier, a test was conducted in the same manner as in Example 1.

The results of the shaking test were as good as those of Example 3A, but in the image forming test under low humidity, some carrier adhesion was observed and the solid image density was higher than that of Example 3A. Although it became a little lower, there was no particular problem in practical use.

Example 4 Phenol 10.0% Formaldehyde 5.0% (Formaldehyde about 37%, Methanol about 10%, balance water) Treated magnetite (same as Example 3A) 85.0% Using ammonia as a basic catalyst and calcium fluoride as a polymerization stabilizer, the mixture was stirred in an aqueous phase, gradually heated to a temperature of 80 ° C., and polymerized for 2 hours. The particle size of the obtained core material was 38 μm. The coating resin used in Example 3A was coated on the resin particles in an amount of 1.
Coating was performed in the same manner as in Example 3A using a toluene solution in which 10% was dissolved so as to be 1%. When a test similar to that of Example 1 was conducted using this carrier, Example 1
Similar good results were obtained.

Comparative Example 5 The magnetic material-dispersed phenol resin particles prepared in Example 4 were used as a carrier without coating. When the same test as in Example 1 was performed, toner spent was observed in the shaking test. Further, in the image output test, the image was distorted, which was considered to be due to the decrease in the applied bias voltage.

[0179]

[Table 1]

[0180]

[Table 2] Example 5 5 parts of a titanium coupling agent (isopropyltriisostearoyl titanate) is added to 500 parts of toluene and well stirred. Next, 500 parts of magnetite (average particle size 0.26 μm) is added, and the solvent is removed by vacuum drying after mixing with a mixer. Using the magnetite thus obtained, a core material was prepared as follows. -Styrene 22.2% 2-Ethylhexyl acrylate 11.1% -Magnetite (particle diameter 0.26 µm) 66.7% The above materials were heated in a container at a temperature of 70 ° C and dissolved to obtain a monomer mixture. . Further, while maintaining the temperature at 70 ° C, an initiator azobisisobutyronitrile was added and dissolved to prepare a monomer composition. This was put into a 2 liter flask containing 1.2 liter of 1% PVA aqueous solution, and stirred at 70 ° C. with a homogenizer at 4500 rpm for 10 minutes to granulate the composition. Then, while stirring with a paddle stirrer,
Polymerization was carried out at ℃ for 10 hours. After the completion of the polymerization reaction, the reaction product was cooled, and the obtained magnetic substance-dispersed styrene acrylic slurry was washed and filtered. This was dried to obtain magnetic substance-dispersed resin particles. The obtained magnetic substance-dispersed resin particles, that is,
The true specific gravity of the core material was 2.2.

The surface of the obtained core material was coated with the following resin coating layer.

Styrene-2-ethylhexyl methacrylate (40/60) Mw / Mn = 2.9 Mw = 42000 Toluene was added so that the coating amount of the styrene-based copolymer would be 0.8% from the above formula. 10% dissolved therein to make a carrier coating solution. This carrier coating solution was applied to the above core material while being dried while being applied by an applicator (supplied by Okada Seiko Co., Ltd .: Spiracoater). The obtained coated magnetic material-dispersed resin carrier is dried at a temperature of 50 ° C. for 1 hour to remove the solvent, and then heated at a temperature of 110 ° C. for 2 hours to coat the core material surface with a resin coating layer. A mold resin carrier was obtained. When the obtained resin-coated magnetic material-dispersed resin carrier was observed with an electron microscope, the core material was uniformly coated with the resin, and the magnetic material particles were exposed substantially uniformly on the coated surface. Was confirmed.

The physical properties of the obtained carrier are summarized in Table 3.

Using this carrier, the same test as in Example 1 was conducted.

As a result, the shaking test as in Example 1,
It was good in the image output test.

Comparative Example 6 A core material was prepared in the same manner as in Example 5 except that untreated magnetite was used, and the same resin coating as in Example 5 was applied to obtain a carrier, and the same test as in Example 1 was performed. I went. When the obtained carrier was observed with an electron microscope, unevenness was found in the coating resin. Further, as a result of the image output test, the halftone portion was found to be rough.

Comparative Example 7 The same test as in Example 1 was conducted using the core material used in Example 5 as a carrier without resin coating.

As a result of the shaking test, some toner spent was recognized on the carrier surface. Further, as a result of the image output test, carrier adhesion was found in the non-image area.

COMPARATIVE EXAMPLE 8 Instead of the core material used in Example 5, 45 μm reduced iron particles were used, and the coating resin used in Example 5 was applied in the same manner as in Example 5 so that the coating amount was 1.2%. A carrier having a true specific gravity of 7.8 was coated. Also, using this carrier, Example 1
Measurements and tests similar to those described above were performed.

As a result of the shaking test, the carrier was not changed from that before shaking, but the burial of the external additive on the toner surface was observed. In addition, as a result of the image output test, the halftone portion was particularly rough.

Example 6 Styrene-2-ethylhexyl acrylate copolymer 35% (monomer composition weight ratio = 55: 45) Magnetite treated with titanium coupling agent 65% (same as used in Example 5) The above materials were sufficiently premixed by a Henschel mixer, melt-kneaded at least twice with a three-roll mill, cooled, and then coarsely pulverized to a particle size of about 2 mm using a hammer mill. Then, it was pulverized to a particle size of about 50 μm by an air jet pulverizer. Further, the obtained finely pulverized product was put into MechanoMill MM-10 (manufactured by Okada Seiko Co., Ltd.) and mechanically spheroidized.

The pulverized finely pulverized particles were further classified to obtain a core material. The particle size of the obtained core material was 48 μm.

A resin coating layer was provided on the surface of the above core material in the same manner as in Example 5 to obtain a resin coated carrier. Further, the same test as in Example 1 was performed on the carrier.

As a result, the shaking test as in Example 1,
It was good in the image output test.

Example 7A 7 parts of a titanium coupling agent (isopropyltridodecylbenzenesulfonyl titanate) are added to 500 parts of toluene and well stirred. Next, 500 parts of magnetite (average particle size 0.35 μm) is added, and after mixing with a mixer, the solvent is removed by vacuum drying. Using the magnetite thus obtained, a core material was manufactured as follows. -Polyester resin obtained by condensing ethoxylated bisphenol-fumaric acid-trimellitic acid 40% (monomer composition weight ratio = 50:40:10) -magnetite (average particle size 0.35 µm) 60% A spherical core material was obtained in the same manner as in Example 6. The particle size of the particles was 54 μm.

The surface of the obtained core material was coated with the following coating resin in the same manner as in Example 5.

Styrene-butyl acrylate copolymer (5
0/50) Mw / Mn = 4.5 Mw = 56000 10% in toluene so that the coating resin amount becomes 1.2%
The dissolved carrier coating solution was used to coat the resin fine particles in the same manner as in Example 5 to obtain a magnetic substance-dispersed resin carrier. Further, when the same test as in Example 1 was conducted, good results were obtained as in Example 1.

Example 7B A core material was produced in the same manner as in Example 7A except that the amount of magnetite in Example 7A was changed to 38% (the rest being polyester resin). The coating resin used in Example 7A was dissolved in 10% of this in toluene so that the coating resin amount was 1.2%, and coating was performed in the same manner as in Example 7A as a coating solution to obtain a magnetic substance-dispersed resin carrier. Obtained. Example 1 using this carrier
Tested in the same way.

The results of the shaking test were as good as those of Example 7A, but in the image forming test under low humidity, some carrier adhesion was observed and the density of the solid image was higher than that of Example 7A. Although it became a little lower, there was no particular problem in practical use.

Example 8 Phenol 10.0% Formaldehyde 5.0% (Formaldehyde about 37%, Methanol about 10%, balance water) Magnetite (particle diameter 0.35 μm) 85.0% (Example 7A) The same as that used in 1.) Using ammonia as a basic catalyst and calcium fluoride as a polymerization stabilizer, the above materials were gradually heated to a temperature of 80 ° C. while stirring in an aqueous phase, and polymerized for 2 hours. I went. The particle diameter of the obtained core material was 42 μm. The coating resin used in Example 7A was applied to the resin particles in an amount of coating resin of 1.
Coating was performed in the same manner as in Example 7A using a toluene solution in which 10% was dissolved so as to be 1%. When a test similar to that of Example 1 was conducted using this carrier, Example 1
Similar good results were obtained.

Comparative Example 9 The magnetic material-dispersed phenol resin particles prepared in Example 8 were used as a carrier without coating. When the same test as in Example 1 was performed, some toner spent was observed in the shaking test. Further, in the image output test, the image was distorted, which was considered to be due to the decrease in the applied bias voltage.

Example 9 As the carrier, the same carrier as in Example 8 was used.

As the toner, styrene-2-ethylhexyl acrylate-100 parts dimethylaminoethyl methacrylate copolymer (monomer composition weight ratio = 80: 15: 5) copper phthalocyanine 4 parts low molecular weight polypropylene 5 parts The above materials were used in the same manner as in Example 1 to give a weight average diameter of 11.7μ
m cyan particles were obtained. 0.8 parts of positively charged colloidal silica treated with amino-modified silicone oil was mixed with 100 parts of the cyan particles by a Henschel mixer to obtain a positively charged cyan toner.

The above cyan toner and carrier were mixed so as to have a toner concentration of 8% to prepare a developer, and a test was conducted in the same manner as in Example 1 using a copying machine NP4835 manufactured by Canon. In addition, the positive chargeability was excellent and a uniform image was obtained.

[0205]

[Table 3]

[0206]

[Table 4] Example 10 5 parts of a titanium-based coupling agent (isopropyltriisostearoyl titanate) was added to 500 parts of toluene,
Stir well. Next, 500 parts of magnetite (average particle size 0.26 μm) is added, and the solvent is removed by vacuum drying after mixing with a mixer. Using the magnetite thus obtained, a core material was prepared as follows. -Styrene 22.2% 2-Ethylhexyl acrylate 11.1% -Magnetite (particle diameter 0.26 µm) 66.7% The above materials were heated in a container at a temperature of 70 ° C and dissolved to obtain a monomer mixture. . Further, while maintaining the temperature at 70 ° C, an initiator azobisisobutyronitrile was added and dissolved to prepare a monomer composition. This was put into a 2 liter flask containing 1.2 liter of 1% PVA aqueous solution, and stirred at 70 ° C. with a homogenizer at 4500 rpm for 10 minutes to granulate the composition. Then, while stirring with a paddle stirrer,
Polymerization was carried out at ℃ for 10 hours. After the completion of the polymerization reaction, the reaction product was cooled, and the obtained magnetic substance-dispersed styrene acrylic slurry was washed and filtered. This was dried to obtain magnetic substance-dispersed resin particles. The true specific gravity of the obtained magnetic substance-dispersed resin particles, that is, the core material, was 2.2.

The surface of the obtained core material was coated with the following resin coating layer. -Styrene-2-ethylhexyl methacrylate copolymer 50% (monomer composition weight ratio = 40: 60, Mw = 42000, Mw / Mn = 2.9) -Vinylidene fluoride-tetrafluoroethylene copolymer 50% (monomer Composition weight ratio = 75: 25, Mw = 210,000) The amount of coating resin of the above copolymer is 0.8% from the above calculation formula.
10% in a mixed solvent of acetone and methyl ethyl ketone (mixing weight ratio = 1: 1) to prepare a carrier coating solution. This carrier coating solution was applied to the above core material while being dried while being applied by an applicator (supplied by Okada Seiko Co., Ltd .: Spiracoater). The obtained coated magnetic material-dispersed resin carrier is dried at a temperature of 40 ° C. for 1 hour to remove the solvent, and then heated at a temperature of 110 ° C. for 2 hours to coat the core material surface with a resin coating layer. A mold resin carrier was obtained. When the obtained resin-coated magnetic material-dispersed resin carrier was observed with an electron microscope, the core material was uniformly coated with the resin, and the magnetic material particles were exposed substantially uniformly on the coated surface. Was confirmed. The same test as in Example 1 was conducted using this carrier. As a result, similar to Example 1, the shaker test and the image output test were good.

Comparative Example 10 A core material was prepared and resin-coated in the same manner as in Example 10 except that untreated magnetite was used and the coating resin was a silicone resin (SR-2400 manufactured by Torre Silicone Co., Ltd.). As a carrier, the same test as in Example 1 was performed.

[0209] As a result, the carrier was found to have uneven coating as observed by an electron microscope. In addition, as a result of the image output test, the halftone was found to be rough.

Comparative Example 11 The same test as in Example 1 was conducted using the core material used in Example 10 as a carrier without resin coating.

As a result of the shaking test, a part of toner spent was found on the carrier surface. Further, as a result of the image output test, carrier adhesion was found in the non-image area.

Comparative Example 12 In the same manner as in Example 10 except that the core material used in Example 10 was replaced by 45 μm reduced iron particles, the coating amount of the coating resin used in Example 10 was adjusted to 1.0%. A carrier having a true specific gravity of 7.8 was coated. Moreover, the same measurement and test as in Example 1 were performed using this carrier.

As a result of the shaking test, the carrier did not change from that before shaking, but the burial of the external additive on the toner surface was observed. In addition, as a result of the image output test, the halftone portion was particularly rough.

Comparative Example 13 Instead of the carrier coating material used in Example 10, the core material used in Example 10 was replaced with vinylidene fluoride-tetrafluoroethylene copolymer (monomer composition weight ratio = 80: 20, Mw = 24000).
0) alone, a mixed solvent of acetone and methyl ethyl ketone (mixing weight ratio = 1: 1) so that the coating resin amount becomes 1.0%.
10% was dissolved in 1) to prepare a carrier coating solution.

The above carrier coating solution was applied in the same manner as in Example 10 to obtain a carrier in which the surface of the carrier core material was coated with the resin coating layer. When the obtained resin carrier was observed with an electron microscope, the coating state was not uniform. Further, the same test as in Example 1 was conducted using this carrier.

As a result of the shaking test, peeling of the coating material was observed, and some detachment of the magnetic material was also observed. further,
As a result of the image output test, image unevenness occurred.

Example 11 Copolymer of styrene-2-ethylhexyl acrylate 50% (monomer composition weight ratio = 55: 45) Magnetite treated with titanium coupling agent 50% (same as used in Example 10) The above materials were sufficiently premixed with a Henschel mixer, melt-kneaded with a three-roll mill at least twice, cooled, and then coarsely pulverized with a hammer mill to a particle size of about 2 mm. Then, it was pulverized to a particle size of about 50 μm by an air jet pulverizer. Further, the obtained finely pulverized product was put into MechanoMill MM-10 (manufactured by Okada Seiko Co., Ltd.) and mechanically spheroidized.

The spheroidized finely pulverized particles were further classified to obtain a core material. The particle size of the obtained core material was 48 μm.

In the above core material, Example 10 was formed on the surface.
A resin coating layer was provided by the same method as in (1) to obtain a resin coated carrier. Further, the same test as in Example 1 was performed on the carrier.

As a result, a shaking test was conducted in the same manner as in Example 1.
It was good in the image output test.

Example 12A 7 parts of a titanium-based coupling agent (isopropyltridodecylbenzenesulfonyl titanate) is added to 100 parts of toluene and well stirred. Next, 500 parts of magnetite (average particle size 0.35 μm) is added, and after mixing with a mixer, the solvent is removed by vacuum drying. Using the magnetite thus obtained, a core material was manufactured as follows. -Polyester resin obtained by condensing ethoxylated bisphenol-fumaric acid-trimellitic acid 40% (monomer composition weight ratio = 50:40:10) -magnetite (average particle size 0.35 µm) 60% In the same manner as in Example 11, a spherical core material was obtained. The particle size of the particles was 54 μm.

The surface of the obtained core material was coated with the following coating resin in the same manner as in Example 10. -Styrene-phenyl acrylate copolymer 50% (monomer composition weight ratio = 50:50 Mw = 64000, Mw / Mn = 4.5) -Vinylidene fluoride-tetrafluoroethylene copolymer 50% (monomer composition weight ratio = 75: 25, Mw = 210,000) was coated on the above core material in the same manner as in Example 10 using a carrier coating solution having 10% dissolved in methyl ethyl ketone so that the coating resin amount was 1.2%, A magnetic material-dispersed resin carrier was obtained. Moreover, when the same test as in Example 1 was performed on the carrier, good results were obtained as in Example 1.

Example 12B A core material was produced in the same manner as in Example 12A except that the amount of magnetite in Example 12A was changed to 38% (the rest being polyester resin). 10% of the coating resin used in Example 12A was dissolved in methyl ethyl ketone so that the coating resin amount was 1.2%, and coating was performed in the same manner as in Example 12A as a coating solution to obtain a magnetic substance-dispersed resin carrier. Obtained. A test was conducted on the carrier in the same manner as in Example 1.

The result of the shaking test was as good as that of Example 12A, however, in the image forming test under low humidity, some carrier adhesion was observed, and the solid image density was higher than that of Example 12A. It became a little lower, but it was not a practical problem.

Example 13 Phenol 10.0% Formaldehyde 5.0% (Formaldehyde about 37%, Methanol about 10%, balance water) Magnetite (particle size 0.35 μm) 85.0% (Example 12A) The same as that used in 1.) Using ammonia as a basic catalyst and calcium fluoride as a polymerization stabilizer, the above materials were gradually heated to a temperature of 80 ° C. while stirring in an aqueous phase, and polymerized for 2 hours. I went. The particle size of the obtained core material was 38 μm. The resin particles were coated in the same manner as in Example 12A using a methyl ethyl ketone solution in which the coating resin used in Example 12A was dissolved in 10% so that the coating resin amount was 1.1%.
Further, when the same test as in Example 1 was performed using the carrier, the same good result as in Example 1 was obtained.

Comparative Example 14 The magnetic material-dispersed phenol resin particles produced in Example 13 were used as a carrier without resin coating. Further, when the same test as in Example 1 was carried out, in the shaking test, some toner spent was observed. Further, in the image output test, the image was distorted, which was considered to be due to the decrease in the applied bias voltage.

Example 14 As the carrier, the same carrier as in Example 13 was used.

Further, as a toner, styrene-2-ethylhexyl acrylate-100 parts dimethylaminoethyl methacrylate copolymer (monomer composition weight ratio = 80: 15: 5) copper phthalocyanine 4 parts low molecular weight polypropylene 5 parts The above materials were used in the same manner as in Example 1 to give a weight average diameter of 11.7μ.
m cyan particles were obtained. 0.8 parts of positively charged colloidal silica treated with amino-modified silicone oil was mixed with 100 parts of the cyan particles by a Henschel mixer to obtain a positively charged cyan toner.

The above cyan toner and carrier were mixed so as to have a toner concentration of 8% to prepare a developer, and the same test as in Example 1 was carried out using a Canon copying machine NP4835. In addition, the positive chargeability was excellent and a uniform image was obtained.

[0230]

[Table 5]

[0231]

[Table 6] Example 15 5 parts of a titanium-based coupling agent (isopropyltriisostearoyl titanate) was added to 500 parts of toluene,
Stir well. Next, 500 parts of magnetite (average particle size: 0.28 μm) is added, and the solvent is removed by vacuum drying after mixing with a mixer. Using the magnetite thus obtained, a core material was prepared as follows.・ Styrene 22.2% ・ 2-Ethylhexyl acrylate 11.1% ・ Magnetite (particle diameter 0.28 μm) 66.7% The above materials are heated in a container at a temperature of 70 ° C. and dissolved to form a monomer mixture. did. Further, while maintaining the temperature at 70 ° C, an initiator azobisisobutyronitrile was added and dissolved to prepare a monomer composition. This was put into a 2 liter flask containing 1.2 liter of 1% PVA aqueous solution, and stirred at 70 ° C. with a homogenizer at 4500 rpm for 10 minutes to granulate the composition. Then, while stirring with a paddle stirrer,
Polymerization was carried out at ℃ for 10 hours. After the completion of the polymerization reaction, the reaction product was cooled, and the obtained magnetic substance-dispersed styrene acrylic slurry was washed and filtered. This was dried to obtain magnetic substance-dispersed resin particles.

The surface of the obtained magnetic material-dispersed resin particles was coated with the following resin coating layer. -Styrene-2-hydroxyethyl methacrylate-50% methyl methacrylate copolymer (monomer composition weight ratio = 35: 8: 57 hydroxyl value (KOHmg / g) = 30 weight average molecular weight = 52,000) -vinylidene fluoride -Tetrafluoroethylene copolymer 50% (monomer composition weight ratio = 75: 25 weight average molecular weight = 210,000) The above-mentioned copolymer has a resin coating amount of 0.8% from the above calculation formula.
10% in a mixed solvent of acetone and methyl ethyl ketone (mixing weight ratio = 1: 1) to prepare a carrier coating solution. This carrier coating solution was applied to the above core material by a coating machine (Okada Seiko Co., Ltd .: Spiracoater) while simultaneously performing coating and drying. The obtained magnetic substance-dispersed resin carrier after coating was dried at a temperature of 90 ° C. for 2 hours to remove the solvent, to obtain a resin-coated magnetic substance-dispersed resin carrier in which magnetic substance-dispersed fine particle surfaces were coated with a resin coating layer. When the obtained resin-coated magnetic material-dispersed resin carrier was observed with an electron microscope, the core material was uniformly coated with the resin, and the magnetic material particles were exposed substantially uniformly on the coated surface. Was confirmed.

On the other hand, a polyester resin obtained by condensing 100 parts of propoxylated bisphenol and fumaric acid, 5 parts of phthalocyanine pigment, 4 parts of chromium complex salt of di-tert-butylsalicylic acid, 4 parts. After that, the mixture was melt-kneaded with a three-roll mill three times, cooled, and then coarsely pulverized with a hammer mill to a particle size of about 1 to 2 mm.
Then, it was pulverized by an air jet pulverizer. Further, the finely pulverized product obtained is classified to have a weight average diameter of 1
2.5 μm negatively chargeable cyan powder (toner)
Got

100 parts of the above-mentioned cyan toner and 0.4 part of silica fine powder hydrophobized with hexamethyldisilazane were mixed by a Henschel mixer to prepare a cyan toner having silica fine powder on the toner particle surface.

This cyan toner and the above resin carrier were mixed in an environment of temperature / humidity of N / N (23 ° C./60% RH) so that the toner concentration would be 10% to obtain a developer. 100 g of the obtained developer was put in a 250 cc plastic bottle and shaken with a Turbula mixer for 1 hour. After that, the developer was taken out and observed with an electron microscope. As a result, desorption of the magnetic material from the carrier, peeling of the coating material, and filming by the toner were not observed. Further, neither detachment of the external additive of the toner nor burial was observed.

Further, a cyan toner and the above resin carrier were mixed in a temperature / humidity L / L (15 ° C./10% RH) environment so that the toner concentration was 10% to obtain a developer. This is a full color laser copier CLC made by Canon under the same environment.
Put it in the developing unit for -1 and drive it with an external motor (peripheral speed 30
Idle rotation was performed for 30 minutes at 0 rpm). After this, CL
Images were printed using C-1 with a development contrast of 300V. As a result, the density of the solid image is sufficient,
The reproducibility of the halftone portion was also good.

Comparative Example 15 Example 15 except that untreated magnetite was used.
A core material was prepared in the same manner as described above, and a silicone resin (SR-2406 manufactured by Toray Silicone Co., Ltd.) was applied as a coating resin in the same manner as in Example 15 to obtain a carrier, and the same test as in Example 15 was performed.

As a result of the shaking test, desorption of the magnetic material from the carrier was observed by observation with an electron microscope.

Further, as a result of the image output test, the image is distorted, which is considered to be caused by the leak of the applied bias voltage. In addition, carrier adhesion to the non-image area was observed.

Comparative Example 16 The same test as in Example 15 was conducted using the core material used in Example 15 as a carrier without resin coating.

As a result of the shaking test, some toner spent was found on the surface of the carrier. Further, as a result of the image output test, carrier adhesion was slightly observed in the non-image area.

Comparative Example 17 In the same manner as in Example 15, the amount of coating resin used in Example 15 was changed to 0.8% by using reduced iron particles of 45 μm in place of the core material used in Example 15. Coated. The same measurement and test as in Example 15 were performed.

As a result of the shaking test, the carrier was not changed from that before the shaking, but it was observed that the external additive was buried on the toner surface. In addition, as a result of the image output test, the halftone portion was particularly rough.

Example 16 Copolymer of styrene-2-ethylhexyl acrylate 50% (monomer composition weight ratio = 55: 45) Magnetite treated with titanium coupling agent 50% (same as used in Example 15) The above materials were sufficiently premixed with a Henschel mixer, melt-kneaded with a three-roll mill at least twice, cooled, and then coarsely pulverized with a hammer mill to a particle size of about 2 mm. Then, it was pulverized to a particle size of about 50 μm by an air jet pulverizer. Further, the obtained finely pulverized product was put into MechanoMill MM-10 (manufactured by Okada Seiko Co., Ltd.) and mechanically spheroidized.

The spheronized finely pulverized particles were further classified to obtain a core material. The particle size of the obtained core material was 46 μm.

In the above core material, Example 15 was formed on the surface.
A resin coating layer was provided by the same method as in (1) to obtain a resin coated carrier. The same test as in Example 15 was performed on the carrier.

As a result, as in Example 15, the shaking test and the image forming test were good.

Comparative Example 18 Vinylidene fluoride-tetrafluoroethylene copolymer (monomer composition weight ratio = 75: 25, weight average) was used in place of the carrier coating material used in Example 15 for the core material used in Example 15. Molecular weight =
210,000) alone was dissolved in a mixed solvent of acetone and methyl ethyl ketone in an amount of 10% so that the resin coating amount was 1.0% to prepare a carrier coating solution.

The above carrier coating solution was applied in the same manner as in Example 15 to obtain a carrier in which the surface of the carrier core material was coated with a resin coating layer.

Microscopic observation revealed that the core material was not uniformly coated.

The same test as in Example 15 was conducted using this carrier.

As a result of the shaking test, peeling of the coating material was observed, and some detachment of the magnetic material was also observed. further,
As a result of the image output test, image unevenness occurred.

Example 17A Polyester resin obtained by condensing 40% (50/40/10) of ethoxylated bisphenol-fumaric acid-trimellitic acid Magnetite (same as in Example 15) 60% In the same manner as in Example 16, spherical magnetic substance-dispersed resin particles were obtained. The particle size of the particles was 53 μm.

The following coating resin was coated on the surface of the obtained magnetic substance-dispersed resin particles in the same manner as in Example 15. Styrene-2-hydroxymethyl methacrylate-40% Methyl methacrylate-Ethyl methacrylate (monomer composition weight ratio = 57: 20: 13: 10 hydroxyl value = 40 weight average molecular weight = 54,000) -methyl etherified melamine formaldehyde Resin 10% -Vinylidene fluoride-tetrafluoroethylene copolymer 50% (monomer composition weight ratio = 75: 25 weight average molecular weight = 210,000) was added to a methyl ethyl ketone solution in an amount of 10% so that the resin coating amount was 1.1%. % Of the carrier coating solution was used to coat the fine particles in the same manner as in Example 15 to obtain a magnetic substance-dispersed resin carrier. Moreover, when the same test as in Example 15 was performed, the same good result as in Example 15 was obtained.

Example 17B A core material was produced in the same manner as in Example 17A except that the amount of magnetite used in Example 17A was changed to 42% (the balance being polyester resin). The coating resin used in Example 17A was dissolved in 10% in a methyl ethyl ketone solution so that the resin coating amount was 0.9%, and the coating solution was coated in the same manner as in Example 17A to obtain a magnetic substance-dispersed resin. Got a career. A test was conducted in the same manner as in Example 15 using this carrier. The result of the shaking test was as good as that of Example 17A, but in the image forming test under low humidity,
Adhesion of carrier was slightly recognized, and the density of the solid image was slightly lower than that of Example 17A, but there was no particular problem in practical use.

Example 18 Phenol 10.0% Formaldehyde 5.0% (Formaldehyde approx. 37%, Methanol approx. 10%, balance water) Magnetite (similar to that used in Example 15) 85.0% Using ammonia as a basic catalyst and calcium fluoride as a polymerization stabilizer, the above materials were gradually heated to a temperature of 80 ° C. with stirring in an aqueous phase, and polymerization was performed for 2 hours. The particle size of the obtained magnetic substance-dispersed resin particles was 40 μm. The resin particles were coated in the same manner as in Example 17A using a methyl ethyl ketone solution in which the coating resin used in Example 17A was dissolved in 10% so that the resin coating amount was 1.0%. When a test similar to that of Example 15 was performed using this carrier, the same good result as that of Example 15 was obtained.

Comparative Example 19 The magnetic material-dispersed phenol resin particles prepared in Example 18 were used as a carrier without coating. When the same test as in Example 15 was performed, toner spent was observed in the shaking test. Further, in the image output test, the image was distorted, which was considered to be due to the decrease in the applied bias voltage.

Example 19 The same carrier as in Example 18 was used as the carrier.

Further, as a toner, styrene-2-ethylhexyl acrylate-100 parts dimethylaminoethyl methacrylate copolymer (monomer composition weight ratio = 80: 13: 7) copper phthalocyanine 4 parts low molecular weight polypropylene 5 parts The above materials were used in the same manner as in Example 15 to give a weight average diameter of 12.1.
Blue particles of μm were obtained. 0.8 parts of positively chargeable colloidal silica treated with amino-modified silicone oil was mixed with 100 parts of the particles by a Henschel mixer to obtain a positively chargeable blue toner.

[0260] The above toner and carrier are mixed in a toner density of 8%.
A developer was prepared by mixing so as to obtain a test product, and a test was conducted in the same manner as in Example 15 using a Canon copying machine NP-4835. was gotten.

[0261]

[Table 7]

[0262]

[Table 8]

[0263]

As described above, when the magnetic carrier coated with the coating resin used in the present invention is used, (1) spent resistance (2) impact resistance (prevention of carrier destruction) (3) toner deterioration Prevention (4) Developability (5) Prevention of carrier adhesion on photoconductor (6) Control of carrier resistance (7) Stabilization of toner chargeability can be sufficiently satisfied, and high-quality images can be obtained for a long time. Therefore, it can be provided stably.

[Brief description of drawings]

FIG. 1 is a schematic view schematically showing an electric resistance measuring device.

FIG. 2 is an explanatory diagram showing an example of a developing device used in the image forming method of the present invention.

[Explanation of symbols]

 1 Lower Electrode 2 Upper Electrode 3 Insulator 4 Ammeter 5 Voltmeter 6 Constant Voltage Device 7 Carrier 8 Guide Ring 11 Latent Image Carrier 22 Development Carrier (Development Sleeve) 23 Permanent Magnet 24 Developer Control Member (Nonmagnetic Blade) 26 Magnetic Carrier Limiting Member 27 Magnetic Carrier 30 Scattering Prevention Electrode Plate 36 Developing Container 37 Toner 40 Sealing Member 60 Toner Replenishing Roller 61 Screw 62 Screw 63 Limit Plate 64 Conveying Screw

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[Procedure amendment]

[Submission date] July 28, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0167

[Correction method] Change

[Correction content]

Example 2 Copolymer of styrene-2-ethylhexyl acrylate 50% (85/15) Treated magnetite (same as in Example 1) 50% After sufficiently premixing the above materials with a Henschel mixer, The mixture was melt-kneaded at least twice with a three-roll mill, cooled, and coarsely pulverized with a hammer mill to a particle size of about 2 mm. Then, it was finely pulverized to a particle size of 47 μm by an air jet type fine pulverizer. Further, the obtained finely pulverized product was put into MechanoMill MM-10 (manufactured by Okada Seiko Co., Ltd.) and mechanically spheroidized.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0191

[Correction method] Change

[Correction content]

Example 6 Styrene-2-ethylhexyl acrylate copolymer 35% (monomer composition weight ratio = 85: 15) Magnetite treated with titanium coupling agent 65% (same as used in Example 5) The above materials were sufficiently premixed by a Henschel mixer, melt-kneaded at least twice with a three-roll mill, cooled, and then coarsely pulverized to a particle size of about 2 mm using a hammer mill. Then, it was pulverized to a particle size of about 50 μm by an air jet pulverizer. Further, the obtained finely pulverized product was put into MechanoMill MM-10 (manufactured by Okada Seiko Co., Ltd.) and mechanically spheroidized.

[Procedure 3]

[Document name to be amended] Statement

[Name of item to be corrected] 0217

[Correction method] Change

[Correction content]

Example 11 Copolymer of styrene-2-ethylhexyl acrylate 50% (monomer composition weight ratio = 85: 15) Magnetite treated with titanium coupling agent 50% (same as used in Example 10) The above materials were sufficiently premixed with a Henschel mixer, melt-kneaded with a three-roll mill at least twice, cooled, and then coarsely pulverized with a hammer mill to a particle size of about 2 mm. Then, it was pulverized to a particle size of about 50 μm by an air jet pulverizer. Further, the obtained finely pulverized product was put into MechanoMill MM-10 (manufactured by Okada Seiko Co., Ltd.) and mechanically spheroidized.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0244

[Correction method] Change

[Correction content]

Example 16 Copolymer of styrene-2-ethylhexyl acrylate 50% (monomer composition weight ratio = 85: 15) Magnetite treated with titanium coupling agent 50% (same as used in Example 15) The above materials were sufficiently premixed with a Henschel mixer, melt-kneaded with a three-roll mill at least twice, cooled, and then coarsely pulverized with a hammer mill to a particle size of about 2 mm. Then, it was pulverized to a particle size of about 50 μm by an air jet pulverizer. Further, the obtained finely pulverized product was put into MechanoMill MM-10 (manufactured by Okada Seiko Co., Ltd.) and mechanically spheroidized.

Claims (12)

[Claims] 1. A magnetic material dispersion type carrier having a core material in which magnetic fine particles are dispersed in a binder resin, and the surface of the core material is coated with a resin, wherein the magnetic fine particles are silane-coupled. The resin which has been treated with an agent and which coats the surface of the core material contains a styrene-acrylic copolymer, and the monomer ratio of the acrylic component in the copolymer is 30 to 90% by weight. The weight average molecular weight of the copolymer is about 20,000 to 500,000,
A magnetic substance-dispersed carrier, wherein the weight average molecular weight / number average molecular weight is 1.5 to 20. 2. A magnetic material dispersion type carrier having a core material in which magnetic fine particles are dispersed in a binder resin, the surface of the core material being coated with a resin, wherein the magnetic fine particles are titanium-based cups. The resin which has been treated with a ring agent and which covers the surface of the core material contains a styrene-acrylic copolymer, and the monomer ratio of the acrylic component in the copolymer is 30 to 90% by weight, The weight average molecular weight of the copolymer is about 20,000 to 500,000,
A magnetic substance-dispersed carrier, wherein the weight average molecular weight / number average molecular weight is 1.5 to 20. 3. A magnetic material dispersion type carrier having a core material in which magnetic fine particles are dispersed in a binder resin, the surface of the core material being coated with a resin, wherein the magnetic fine particles are titanium-based cups. The resin that has been treated with a ring agent and covers the surface of the core material contains a styrene-acrylic copolymer and a fluorine-containing resin, and the acrylic resin in the copolymer of the styrene-acrylic copolymer is used. The monomer ratio of the components is 30 to 90% by weight, the weight average molecular weight has a distribution of about 20,000 to 500,000, and the weight average molecular weight / number average molecular weight is 1.5 to 20. The mixing ratio of the fluororesin to the coalesce is 5:95 to 95: 5 by weight ratio (weight of the fluororesin: weight of the copolymer). A. 4. A magnetic material dispersion type carrier comprising a core material in which magnetic material particles are dispersed in a binder resin, and the surface of the core material is coated with resin, wherein the magnetic material particles are titanium-based cups. The resin that has been treated with a ring agent and covers the surface of the core material has a hydroxyl value of 1 to 1.
A magnetic substance-dispersed carrier characterized by containing a vinyl copolymer having No. 00 and a fluorine-containing resin. 5. The magnetic substance dispersion type carrier according to claim 1, wherein the true specific gravity of the carrier is 1.5 to 5.0. 6. The magnetic body according to claim 1, wherein the magnetic force of the magnetic body dispersed in the core material is 60 emu / g or more under a magnetic field of 10 K Oersted. Decentralized carrier. 7. The magnetic material dispersion type carrier according to claim 1, wherein the particle size of the carrier is 10 μm to 60 μm. 8. The carrier has a specific resistance of 10 ⁷ Ω · cm-1.
The magnetic substance-dispersed carrier according to claim 1, wherein the carrier is 0 ¹⁴ Ω · cm. 9. The magnetic substance-dispersed carrier according to claim 1, wherein a core material obtained by dispersing magnetic fine particles in a binder resin is produced by a polymerization method. 10. A two-component developer for developing an electrostatic charge image, which comprises the magnetic substance-dispersed carrier according to claim 1 and a toner. 11. The method for producing a magnetic substance-dispersed carrier according to claim 1, wherein the resin material and a carrier coating solution containing a solvent that disperses or dissolves the resin material are combined. A method for producing a magnetic substance-dispersed carrier, which comprises coating a core material obtained by dispersing magnetic fine particles in a resin to be coated and drying the resin to coat the surface of the core material with a resin. 12. An image forming method comprising developing a latent image formed on a photoconductor by applying a bias voltage in a developing area with the two-component developer for developing an electrostatic charge image according to claim 10. .