JP2000039742A - Magnetic coated carrier and two-component developer using same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a magnetic coated carrier and a two-component developer capable of maintaining a clear image free from the lowering of image density and fog even after copying repeated many times in the continuous copying of a color original having a large image area. SOLUTION: The magnetic coated carrier has a magnetic carrier core material contg. at least a resin binder, ferromagnetic compd. particles and nonmagnetic inorg. compd. particles and a coating layer. The total amt. of the ferromagnetic compd. particles and the nonmagnetic inorg. compd. particles contained in the magnetic carrier core material is 60-99 wt.% based on the amt. of the magnetic coated carrier. The resin binder contains at least a phenolic resin and the magnetic carrier core material contains a nitrogen-contg. compd., or a phenolic resin and a nitrogen-contg. compd. bond to each other in the magnetic carrier core material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic carrier and a two-component developer used for developing an electrostatic latent image in electrophotography, electrostatic recording and the like.

[0002]

2. Description of the Related Art U.S. Pat.
7, 691, JP-B-42-23910 and JP-B-43-24748 describe various methods. In each of these methods, an electrostatic latent image is formed by irradiating a photoconductive layer with a light image corresponding to a document, and then a toner called a toner having an opposite polarity is formed on the electrostatic latent image. The electrostatic latent image is developed by adhering fine powder, and if necessary, a toner image is transferred to a transfer material such as paper, and then fixed by heat, pressure, heating, pressurization, or solvent vapor to obtain a copy. What you get.

In the step of developing the electrostatic latent image, a toner image is formed on the charged toner particles by utilizing the electrostatic interaction of the electrostatic latent image. In general, among the methods of developing such an electrostatic latent image using toner, a two-component developer in which toner is mixed with a carrier is suitably used for a full-color copying machine or a printer that requires particularly high image quality.

In recent years, the electrophotographic method has been widely used in copiers and printers, and is required to be able to handle various objects such as fine lines, small letters, photographs, and color originals. Further, higher image quality, higher quality, higher speed, and continuity are also required, and these requirements are expected to increase in the future.

Conventionally, iron powder carriers,
Ferrite carriers or binder type carriers (composite particles in which magnetic fine particles are dispersed in a resin) and the like have been developed and put into practical use.

The iron powder carrier has a flake shape, a sponge shape, and a spherical shape.
A degree, because the bulk density as high as ^{3g / cm 3 ~4g / cm 3} , in order to stir in the developing machine requires a large driving force, many mechanical wear, spent of the toner, It tends to cause deterioration of the chargeability of the carrier itself and damage to the photoreceptor.

The ferrite carrier is spherical, has a specific gravity of about 4.5 to 5.5, and has a bulk density of 2 g / cm ³ to
Since it is about 3 g / cm ³ , the weight, which is a drawback of the iron powder carrier, can be solved to some extent, but it is still not enough.

[0008] The binder type carrier is 2.5 g / cm
^The bulk density is as small as about ³ or less, and the particles have less shape distortion, and the particle strength tends to be high. And the particle size thereof can be controlled in a wide range, so that it is most expected in a high-speed copying machine in which the number of rotations of a developing sleeve or a magnet in the sleeve is large, a high-speed laser beam printer of a general-purpose computer, and the like.

First, the carrier is required to have an appropriate saturation magnetization value, particularly a saturation magnetization value of about 20 to 70 emu / g. That is, a good image can be obtained by setting the value of the saturation magnetization of the carrier in the range of 20 to 70 emu / g. By setting the magnetization value to 20 emu / g or more, the carrier forming the so-called “spike” of the magnet brush on the sleeve separates from the “spike” due to the low magnetic force and flies to the photoconductor, So-called carrier adhesion that adheres to the photoreceptor hardly occurs. In addition, 70 emu /
g or less to suppress the mechanical force applied to the toner,
Crushing of the toner can be prevented. Therefore, the saturation magnetization of the carrier is required to be in the range of 20 to 70 emu / g.

Second, the carrier is required to charge the toner quickly. That is, it is important to improve the mixing property with the toner, and for that purpose, it is required to have an appropriate specific gravity, particularly, a specific gravity of about 2.5 to 5.2. Although increasing the specific gravity of the carrier is advantageous for the mixing property with the toner itself, it is also required that the toner is not damaged, so that the so-called spent is prevented from occurring, and the developing machine is reduced in size and In order to reduce the weight, the specific gravity of the carrier is desirably small. Therefore, it is required that the specific gravity is appropriate, in particular, about 2.5 to 5.2.

[0011] The third point required for the carrier is a relatively high electric resistance value, especially 10 ¹¹ to 10 ¹⁵ Ω.
cm. That is,
When the volume resistivity is as low as 10 ⁶ Ωcm or less as in the case of an iron powder carrier, the charge is injected from the sleeve to cause the carrier to adhere to the image portion of the photoreceptor, or the latent image charge escapes via the carrier, resulting in a latent image. There are problems such as occurrence of disorder and loss of images.

In order to solve these problems, a binder type carrier in which the surface of the carrier particles is coated with a resin to increase the electric resistance of the carrier has been proposed (Japanese Patent Laid-Open No. 47-1395).
No. 4, JP-A-54-660).

However, since these resins are insulators, the electrical resistance of the carrier itself is likely to be higher than 10 ¹⁵ Ωcm, carrier charges are less likely to leak, and the charge amount of the toner is also increased. Although the obtained image is an image with a sharp edge, on the other hand, on a large-area image surface, there is a problem that the image density at the center becomes extremely low.

From these facts, a relatively high electric resistance value is required, and specifically, a specific volume resistance value of 10 ¹¹ to 10 is required.
^{About 15} Ωcm is required.

The resins used for the binder type carrier are roughly classified into thermoplastic resins such as vinyl, styrene and acrylic resins and thermosetting resins such as phenol resins, melamine resins and epoxy resins. Although a resin is known, generally, a thermoplastic resin which can be easily granulated is used, and it is said that a thermosetting resin has a practical problem since it is difficult to form a spheroid.

On the other hand, a thermosetting resin is more excellent in durability, impact resistance and heat resistance than a thermoplastic resin. Therefore, a binder type comprising inorganic particles and a thermosetting resin taking advantage of these advantages is used. There is a strong demand for a carrier, and composite particles using a phenol resin as a thermosetting resin and a ferromagnetic powder as inorganic particles are known (Japanese Unexamined Patent Application Publication No. Hei.
JP 220068, JP-A-4-100850)
However, there is no end to the demand for higher performance of the binder type carrier.

In general, phenolic resins as thermosetting resins are broadly classified into resol resins, which react phenols and aldehydes in the presence of a basic catalyst, and novolak resins, which react in the presence of an acidic catalyst. Since the resole resin contains many methylol groups in the molecule, it can be cured only by heating without using a curing agent, so that it is suitable for a spherical carrier. However, on the other hand, it has a disadvantage that it is easily affected by temperature and humidity when mixed with toner due to the influence of residual groups.

[0018]

SUMMARY OF THE INVENTION An object of the present invention is to provide a magnetic coated carrier which solves the above-mentioned problems, and a two-component developer using the magnetic coated carrier.

An object of the present invention is to provide a magnetic coated carrier capable of forming a high-quality toner image by preventing or suppressing the occurrence of fog without carrier adhesion, and a two-component developer using the magnetic coated carrier. It is in.

An object of the present invention is to provide a magnetic coated carrier capable of forming a high-definition color toner image with a high image density without being affected by temperature and humidity, and a two-component developer using the magnetic coated carrier. It is in.

An object of the present invention is to provide a magnetic coated carrier which is excellent in durability without causing image deterioration even when multiple images are formed, and a two-component developer using the magnetic coated carrier.

[0022]

According to the present invention, there is provided a magnetic carrier core material containing at least a binder resin, ferromagnetic compound particles and non-magnetic compound particles, and one or more magnetic carrier core materials covering the core material surface. A magnetically coated carrier having a coating layer having at least one kind of resin, wherein the magnetically coated carrier has a spherical shape, a number average particle size of 5 to 100 μm, and a ferromagnetic compound contained in the magnetic carrier core material. The total amount of the particles and the nonmagnetic inorganic compound particles is 60 to 99% by weight based on the magnetic coat carrier, and the binder resin is
It contains at least a phenolic resin, and the magnetic carrier core material contains a nitrogen-containing compound, or
The present invention relates to a magnetic-coated carrier characterized in that a phenol resin and a nitrogen-containing compound are bonded to each other in the magnetic carrier core material, and a two-component developer using the magnetic-coated carrier.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION The present inventors have conducted various studies and studies to improve the above-mentioned conventional problems, and as a result, have found that a phenol resin containing a nitrogen-containing compound as a binder resin for magnetic particles, The present inventors have found that a carrier using a phenol resin copolymerized with a contained compound is effective in improving various properties, and have completed the present invention.

Hereinafter, the present invention will be described in detail. First, the magnetic carrier according to the present invention has a number-based average particle size of 5 to 5.
100 μm. Particles having an average particle size of less than 5 μm
When the carrier is produced, secondary aggregation is liable to occur. If the thickness exceeds 100 μm, a clear image cannot be obtained. In particular, in order to obtain high image quality and prevent carrier adhesion, 10 to 10
60 μm, preferably 15 to 50 μm is good.

The spherical magnetic coated carrier according to the present invention comprises:
Including ferromagnetic compound particles and non-magnetic inorganic compound particles, the total amount of ferromagnetic compound particles and non-magnetic inorganic compound particles is 60 to
It is 99% by weight, more preferably 80 to 99% by weight. If it is less than 60% by weight, the proportion of the resin increases, so that an appropriate specific gravity cannot be obtained. If it exceeds 99% by weight, the binder is insufficient and particles having sufficient strength cannot be obtained.

The content of the nonmagnetic inorganic compound particles is in the range of 5 to 70% by weight based on the total amount of the ferromagnetic compound particles and the nonmagnetic inorganic compound particles. Preferably 10-7
The range is 0% by weight. If it is less than 5% by weight, a moderately high electric resistance cannot be obtained. On the other hand, if it exceeds 70% by weight, a sufficient magnetization value cannot be obtained, which is not preferable.

The bulk density of the magnetic coated carrier used in the present invention is preferably 3.0 g / cm ³ or less. Preferably, it is 2.0 g / cm ³ . If it exceeds 3.0 g / cm ³ , the share in the developer becomes large, and it becomes easy to cause spent by the toner or peeling of the coating resin. The measurement of the bulk density of the carrier is performed according to the method described in JIS K5101.

The shape of the magnetic coated carrier is appropriately selected so as to be suitable for a predetermined system. However, in the magnetic coated carrier used in the present invention,
The shape factor SF1 representing the sphericity is preferably 200 or less, more preferably 150 or less. When the SF1 exceeds 200, the magnetic coat carrier has poor fluidity as a developer, and has a low image quality due to a decrease in frictional charging ability to toner and an uneven shape of a magnetic brush at a developing pole. It is difficult to obtain a proper image. The sphericity of the carrier was measured by randomly extracting 300 or more carriers using a field emission scanning electron microscope S-800 manufactured by Hitachi, Ltd., and using an image processing analyzer Luzex3 manufactured by Nireco. This is performed by obtaining SF1 derived by the following equation.

[0029]

[Outside 1] [Where MX LNG indicates the maximum diameter of the carrier, and AR
EA indicates the projected area of the carrier. ]

Here, as SF1 is closer to 100, it means that it is more spherical.

[0031] The ratio r _b / r _a between the average particle size r _b of the average particle diameter r _a nonmagnetic inorganic compound particles of the ferromagnetic compound particles in the magnetic coated carrier of the present invention, it is beyond the 1.0 Is preferred. More preferably, it is in the range of 1.2 to 5.0. In the case of 1.0 or less, the difference in size between the ferromagnetic compound particles and the nonmagnetic inorganic compound particles disappears or the ferromagnetic compound particles become relatively larger, so that the ferromagnetic compound particles occupying the surface And the electric resistance of the carrier core material before forming the coating layer with the resin is reduced to less than 10 ¹⁰ Ωcm. In order to obtain a relatively high electric resistance, it is necessary to use the resin. It is necessary to increase the thickness of the coating layer. In addition, for uniform mixing, the ratio r _b / r _a is preferably 5.0 or less.

The magnetic coated carrier of the present invention has a saturation magnetization of 20 to 70 emu / g. Preferably 20 to 5
0 emu / g. When the saturation magnetization exceeds 70 emu / g, the transportability due to the magnetic force of the carrier increases,
There is a possibility that the mechanical force on the toner is increased and the toner is crushed. Further, the saturation magnetization value is 20 emu / g.
If it is less than 3, the carrier is detached from the surface of the developing sleeve during the transport of the developer, and adheres to the surface of the photoreceptor to cause a defect in an image.

The magnetic coated carrier according to the present invention preferably has a specific gravity of 2.5 to 5.2. More preferably, it is 2.5 to 4.5.

The magnetic coated carrier according to the present invention preferably has an electric resistance of 10 ¹¹ to 10 ¹⁵ Ωcm.
If it is less than 10 ¹¹ Ωcm, the charge on the electrostatic latent image tends to flow through the carrier, and the image is likely to be disturbed or chipped. If it exceeds 10 ¹⁵ Ωcm, leakage of carrier charges hardly occurs, the charge amount of the toner increases, and problems such as extremely low image density at the center of the solid black portion occur.

Next, a method for producing the magnetic coated carrier according to the present invention as described above will be described.

The ferromagnetic compound particles used in the present invention include ferromagnetic iron oxide particles such as magnetite and maghemite, and metals other than iron (Mn, Ni, Zn, Mg, Cu, etc.).
Spinel ferrite particles containing one or more kinds of
Magnetoplumbite type ferrite particles such as barium ferrite, and fine particles of iron or iron alloy having an oxide film on the surface can be used. Preferred are ferromagnetic iron oxide particles such as magnetite or magnetic ferrite particles containing magnesium and iron. The particle size of the ferromagnetic compound particles,
The thickness is desirably 0.02 to 5 μm, and preferably 0.05 to 3 μm in consideration of the dispersion in an aqueous medium and the strength of the formed spherical composite particles. The shape may be any of a granular shape, a spherical shape, and a needle shape. Further, the ferromagnetic compound preferably has a saturation magnetization σ _s of 20 emu / g or more, more preferably 30 emu / g or more.

The nonmagnetic inorganic compound particles used in the present invention have an electric resistance of 10 ¹⁰ Ωcm or more, preferably 10 ¹⁰ Ωcm or more.
¹² Ωcm or more, for example, metal oxide fine particles such as titanium oxide, silica, alumina, zinc oxide, magnesium oxide, hematite, goethite and ilmenite, silicon carbide, aluminum nitride, boron nitride and the like can be used. . Those having little difference in specific gravity from ferromagnetic compound particles, hematite, zinc oxide, titanium oxide and the like are more preferable. The particle diameter of the non-magnetic inorganic compound particles used in the production of the magnetic carrier core material is preferably 0.05 to 5 μm, and considering the dispersion in an aqueous medium and the strength of the composite particles to be formed, 0.1 to 0.1 μm. More preferably, it is 3 μm. The nonmagnetic inorganic compound has a saturation magnetization σ _s
Is preferably 10 emu / g or less, and 5 emu / g or less.
/ G or less. On the other hand, the particle size of the non-magnetic inorganic compound particles used for the coating layer in the present invention,
In consideration of the thickness of the coating layer, the thickness is 1 μm or less, preferably 0.5 μm or less. The shape may be any of a granular shape, a spherical shape, and a needle shape.

The ferromagnetic compound particles and nonmagnetic inorganic compound particles in the present invention can be used as they are without surface treatment, but may be subjected to lipophilic treatment in advance. When ferromagnetic compound particles and non-magnetic inorganic compound particles not subjected to lipophilic treatment are used, hydrophilic organic compounds such as carboxymethylcellulose and polyvinyl alcohol and fluorine compounds such as calcium fluoride are used as suspension stabilizers. By adding a compound or the like, spherical particles are easily generated.

The lipophilic treatment may be carried out by adding a coupling agent such as a silane coupling agent or a titanate coupling agent to the ferromagnetic compound particles or the like and coating the mixture, or in an aqueous solvent containing a surfactant. There is a method of dispersing ferromagnetic compound particles and the like, and adsorbing a surfactant on the surface of the particles. The ferromagnetic compound particles and the non-magnetic inorganic compound particles may be subjected to lipophilic treatment at the same time, or may be treated separately. Alternatively, only one of the lipophilic treatments may be performed.

Examples of the silane coupling agent include those having a hydrophobic group, an amino group, and an epoxy group. Examples of the silane coupling agent having a hydrophobic group include vinyltrichlorosilane, vinyltriethoxysilane, and vinyl.
Tris (β-methoxy) silane and the like.

Examples of the silane coupling agent having an amino group include γ-aminopropyltriethoxysilane, N-
β- (aminoethyl) -γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) -γ-aminopropylmethyldimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane and the like.

Examples of the silane coupling agent having an epoxy group include γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyltrimethoxysilane, β- (3,4-epoxycyclohexyl) trimethoxysilane and the like. There is.

Examples of titanate-based coupling agents include isopropyl triisostearoyl titanate, isopropyl tridodecylbenzenesulfonyl titanate, and isopropyl tris (dioctyl pyrophosphate) titanate.

As the surfactant, commercially available surfactants can be used, and those having a ferromagnetic iron compound particle, a non-magnetic inorganic compound particle or a functional group capable of binding to a hydroxyl group on the particle surface can be used. Desirably, ionic or cationic is preferred.

Although the object of the present invention can be achieved by any of the above-described treatment methods, treatment with a silane coupling agent having an amino group or an epoxy group is preferable in consideration of the adhesiveness to a phenol resin.

The magnetic carrier core material according to the present invention contains at least a phenol resin as a binder resin, and the phenol resin is obtained by reacting a phenol and an aldehyde in the presence of a basic catalyst.

The phenols used in the present invention include phenol itself, alkylphenols such as m-cresol, p-tert-butylphenol, o-propylphenol, resorcinol, bisphenol A, and a part of benzene nucleus or alkyl group. Alternatively, compounds having a phenolic hydroxyl group such as halogenated phenols, all of which are substituted with chlorine atoms and bromine atoms, may be mentioned, of which phenol is most preferred. When a substance other than phenols is used, particles may not be easily formed, or even if particles are formed, the particles may have an irregular shape.

Examples of the aldehyde used in the present invention include formaldehyde and furfural in either form of formalin or paraaldehyde, with formaldehyde being particularly preferred.

The molar ratio of the aldehyde to the phenol is preferably from 1 to 4, particularly preferably from 1.2 to 3. The molar ratio of aldehydes to phenols is 1
If the particle size is smaller, particles are difficult to be formed, and even if formed, the curing of the resin is difficult to progress, so that the strength of the formed particles tends to be weak. On the other hand, the molar ratio of aldehydes to phenols is 4 If it is larger than that, unreacted aldehydes remaining in the aqueous medium after the reaction tend to increase.

Examples of the basic catalyst used in the present invention include those used in the production of ordinary resol resins, for example, aqueous ammonia, hexamethylenetetramine and alkylamines such as dimethylamine, diethyltriamine and polyethyleneimine. The molar ratio of these basic catalysts to phenols is preferably from 0.02 to 0.3.

In the present invention, other resins can be used as the binder resin in accordance with the phenol resin to the extent that the effects of the present invention are not impaired.

As an example containing a nitrogen-containing compound, a binder resin carrier using melamine has been described in, for example, JP-A-8-160671, but as in the present invention, it is used in combination with a phenol resin. No point is described, and the effect of stabilizing charging over a long period cannot be achieved as in the present invention.

JP-A-4-34441 discloses that a polyamide layer is formed on the surface of magnetic particles, and JP-A-4-14055 describes that an acrylonitrile resin layer is formed on a coating layer. In both cases, in consideration of toner spent, etc., when an original image having a high image ratio is continuously printed as in the present invention, it is not always satisfactory.

Also, Japanese Patent Application Laid-Open No. 8-334493 discloses that
There is a statement that isocyanate is copolymerized, but there is no suggestion as a coat carrier, and it is not always satisfactory when the image ratio is high.

In the present invention, the production of the magnetic carrier core material is carried out in an aqueous medium. In this case, the amount of water charged is a ratio of the total amount of the ferromagnetic compound particles and the nonmagnetic inorganic compound particles to the entire raw material. Total solids concentration is 30-9
It is preferable that the content be 5% by weight,
It is preferable that the content be about 90% by weight.

In the reaction, first, phenols, formalins, water, a nitrogen-containing compound, ferromagnetic compound particles and non-magnetic inorganic compound particles are charged into a reaction vessel, sufficiently stirred, and then a basic catalyst is added. While raising the temperature, the reaction temperature is adjusted to 70 to 90 ° C., and the phenol resin is cured. At this time, it is desirable to slowly raise the temperature in order to obtain a magnetic carrier core material having a high sphericity. The heating rate is
Preferably it is 0.5 to 1.5 ° C / min, more preferably 0.1 to 1.5 ° C / min.
8 to 1.2 ° C / min.

After the cured reaction product is cooled to 40 ° C. or lower, the obtained aqueous dispersion is separated into solid and liquid by a conventional method such as filtration and centrifugation, then washed and dried to obtain a ferromagnetic compound. A magnetic carrier core material obtained by combining the particles and the non-magnetic inorganic compound particles with a phenol resin as a binder is obtained. The method of the present invention can be carried out by either a continuous method or a batch method, but is usually carried out by a batch method.

In the present invention, the nitrogen-containing compound contained in the carrier core material or bonded to the phenol resin comprises an aromatic amine compound having at least one active hydrogen bonded to a nitrogen atom, an amide compound and a thioamide compound. At least one nitrogen-containing compound selected from the group, urea, thiourea, melamine, guanidine, guanamine, dicyandiamide and cyanuric acid, aromatic isocyanates, aliphatic isocyanates such as diphenylmethane-4,4'-diisocyanate Examples thereof include isocyanates such as a phosphate, polyphenylene polyphenyl polyisocyanate, and hexamethylene diisocyanate, imidazoles, quaternary ammonium salts, and acrylonitrile, and one or more kinds thereof can be used. The preferred amount is 2 to 200% by weight based on phenols. If the amount used is less than 2% by weight, the effect is small, and if it exceeds 200% by weight, the storage stability at high temperatures decreases.

Further, in order to sharpen the particle size distribution at the time of polymerization, the content is preferably 2 to 100% by weight, and more preferably 2 to 50% by weight from the viewpoint of improving the fluidity of the particles.

In the present invention, when the magnetic carrier core material has a layer containing or binding a nitrogen-containing compound on its surface, the effect of having the nitrogen-containing compound is most effectively exerted. You.

An example will be described more specifically.

Phenols containing the nitrogen-containing compound,
After formalins, water and a magnetic carrier core material are charged into a reaction vessel and sufficiently stirred, ammonia is added and the temperature is raised while stirring, the reaction temperature is adjusted to 70 to 90 ° C., and the phenol resin is cured. The reaction product after curing is cooled to 40 ° C. or lower, and the obtained aqueous dispersion is filtered, solid-liquid separated according to a conventional method such as centrifugation, washed and dried,
Magnetic carrier particles having a layer made of a phenol resin having a nitrogen-containing compound copolymerized on the particle surface are obtained. At this time, in order to sufficiently cure the resin, for example, 1
It is necessary to sufficiently cure the resin at a temperature of about 00 to 350 ° C. Further, in order to prevent oxidation of the ferromagnetic compound particles, an inert gas such as helium, argon, nitrogen, etc. It is desirable to process while flowing. The heat treatment lamp may be either a fixed type or a rotary type, but a rotary type is preferable in order to prevent aggregation of particles.

The magnetic coated carrier according to the present invention has a coating layer made of one or more resins on the surface of the magnetic carrier core material. In the case of resin, the coating amount is
It is 0.01 to 5% by weight, preferably 0.05 to 3% by weight, based on the carrier core particles. If the amount of the resin to be coated is less than 0.01% by weight, the effect of sufficient coating cannot be obtained, and if it exceeds 5% by weight, coalescence of the particles and the like tend to occur.

As the coating method, any of the conventionally known carrier resin coating methods such as a method of dissolving or suspending a coating material such as a resin in a solvent, coating and adhering to a carrier, and a method of simply mixing with a powder are used. Can also be applied.

The coating material for the carrier surface varies depending on the toner material, and both thermosetting resins and thermoplastic resins can be used. For example, polytetrafluoroethylene, monochlorotrifluoroethylene polymer, polyvinylidene fluoride, silicone Resin, polyester resin,
Examples include metal compounds of di-tartary butyl salicylic acid, styrene resins, acrylic resins, polyamides, polyvinyl butyral, nigrosine, amino acrylate resins, basic dyes and lakes thereof, silica fine powder, and alumina fine powder. These are suitably used alone or in combination.

The amount of treatment (coating) of the above coating material is preferably 0.01 to 30% by weight, more preferably 0.1 to 20% by weight, based on the weight of the carrier after the treatment.

The average particle size of these carriers is preferably 1
It is good to have 0-100 micrometers, More preferably, it is 20-50 micrometers.

In a particularly preferred embodiment, the surface of the magnetic carrier core material is prepared by combining (i) a fluorine resin and a styrene resin (for example, a combination of polyvinylidene fluoride and a styrene-methyl methacrylate resin, polytetrafluoroethylene). And a styrene-methyl methacrylate resin, a combination of a fluorine-based copolymer and a styrene-based copolymer), preferably in a ratio of 90:10 to 20:80, more preferably in a ratio of 70:30 to 30:70. Or (ii) a silicone resin, preferably 0.01 to 5% by weight, more preferably 0.1 to 3% by weight.
Coated carriers are included.

As the fluorine-based copolymer, a vinylidene fluoride-tetrafluoroethylene copolymer (10:90 to 9
0:10). As the styrene-based copolymer, a styrene-2-ethylhexyl acrylate copolymer (2
0: 80-80: 20), styrene-2-ethylhexyl acrylate-methyl methacrylate copolymer (20-6)
0: 5 to 30:10 to 50).

The coating resin may contain other resin particles or inorganic compound particles. Further, it is more preferable to modify the surface with another material such as a reactive coupling agent before coating the resin. By performing the surface modification, the adhesion between the resin layer and the carrier core material particles is improved, and more excellent durability can be obtained.

Examples of the reactive coupling agent for the magnetic carrier core material of the present invention include the following coupling agents.

Examples of the silane coupling agent include those having a hydrophobic group, an amino group, and an epoxy group. Examples of the silane coupling agent having a hydrophobic group include vinyl trichlorosilane, vinyl triethoxysilane, and vinyl.
Tris (β-methoxy) silane and the like.

As silane coupling agents having an amino group, γ-aminopropyltriethoxysilane, N
-Β- (aminoethyl) -γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) -γ-aminopropylmethyldimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane and the like.

Examples of the silane coupling agent having an epoxy group include γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyltrimethoxysilane, β- (3,4-epoxycyclohexyl) trimethoxysilane and the like. There is.

Examples of the titanate coupling agent include isopropyl triisostearoyl titanate, isopropyl tridodecylbenzenesulfonyl titanate, and isopropyl tris (dioctyl pyrophosphate) titanate.

Among these, in order to further increase the affinity on the surface of the carrier core material and the negative chargeability when using a negative charge toner, the reactive coupling agent used is an aminosilane coupling agent. Those having a primary amino group are particularly preferred.

The coated carrier has a sharp particle size distribution, provides favorable triboelectric charging properties for the toner used in the present invention, and has the effect of improving electrophotographic properties.

In the present invention, when a two-component developer is prepared by mixing a toner and a carrier, the mixing ratio is from 2% by weight to 15% by weight, preferably from 4% by weight as a toner concentration in the developer. Good results are obtained with 13% by weight. When the toner concentration is less than 2% by weight, the image density becomes low, and when it exceeds 15% by weight, fog and scattering in the machine are increased, and the useful life of the developer is shortened.

The toner used in the present invention has a weight average particle size of 3 to 9 μm, preferably 3 to 8 μm. In addition, the cumulative value of the distribution not more than 1/2 times the number average particle diameter is 20 number% or less, and the weight average particle diameter is 2% or less.
It is important that the distribution cumulative value of the diameter larger than the diameter is 10% by volume or less in order to satisfy favorable charging without reversal components, reproducibility of latent image dots, and the like. In order to further improve the triboelectric chargeability of the toner and enhance the dot reproducibility, the cumulative value of distribution having a diameter equal to or less than 1/2 times the number average particle diameter is 15% by number or less, and the particle having a diameter equal to or more than twice the diameter of the weight average particle diameter. Distribution cumulative value is 5% by volume
It is more preferred that: Further, the cumulative distribution value of the half or less of the number average particle diameter is 10% by number or less, and the cumulative distribution value of the twice or more diameter of the weight average particle diameter is 2% by volume.
It is more preferred that:

The weight average particle diameter (D4) of the toner is 10 μm
Is exceeded, the toner particles for developing the electrostatic latent image become large, so that no matter how much the magnetic force of the magnetic coat carrier is lowered, development that is not faithful to the latent image cannot be performed. Splatters become severe. On the other hand, a toner having a weight average particle diameter of 1 μm or less causes inconvenience in handling properties as a powder.

If the cumulative value of the distribution of not more than half the number average particle diameter exceeds 20% by number, the toner electrostatic charge cannot be applied to the fine toner particles, and the tribo distribution of the toner becomes wide. Problems such as a change in particle size in durability are likely to occur due to poor charging (generation of a reversal component) and uneven distribution of the particle size of the developed toner. On the other hand, if the cumulative value of the distribution having a diameter twice as large as the weight average particle diameter exceeds 10% by volume, good frictional charging with the magnetic coat carrier cannot be performed, and it becomes difficult to faithfully reproduce the latent image. The particle size distribution of the toner can be measured by, for example, a method using a Coulter counter.

The particle size of the toner used in the present invention is closely related to the particle size of the magnetic coated carrier. When the number average particle diameter of the magnetic carrier is 20 to 60 μm, it is necessary for the toner to have a weight average diameter of 3 to 8 μm in order to improve the chargeability and improve the image quality. On the other hand, when the number average particle diameter of the magnetic coated carrier is 5 to 35 μm, the toner has a weight average diameter of 1 to 6 μm in order to prevent the deterioration of the developer and to improve the image quality at the initial stage and especially after the durability.
m is preferable.

Further, the toner of the present invention has a shape factor SF1
Is preferably 100 to 150, more preferably 100 to
A value of 130 is good for enhancing practical filming resistance and transferability / developability.

The toner having the above-mentioned shape factor is not only essential for faithfully reproducing finer latent image dots in order to improve the image quality, but also resists the high mechanical stress in the developing device, thereby making the developer Deterioration can be reduced. Further, transferability / developability during high-speed copying can be sufficiently ensured. The shape factor SF1 of the toner is 1
If it is larger than 50, it becomes gradually more amorphous than spherical, so that it becomes difficult to obtain uniform charging characteristics and the fluidity is impaired. Because the friction with the charge applying member increases, the toner breaks and becomes finer,
Fogging is likely to occur in the formed image, and the definition deteriorates.

As the binder resin used in the toner of the present invention, the following binder resins can be used.

For example, homopolymers of styrene and its substituted substances such as polystyrene, poly-p-chlorostyrene and polyvinyltoluene; styrene-p-chlorostyrene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene Copolymer, styrene-acrylate copolymer, styrene-methacrylate 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; phenolic resin; natural modified phenolic resin; natural resin modified maleic acid resin; acrylic resin; methacrylic resin; polyvinyl acetate; silicone resin; polyester resin; Resin; Xylene resin; Polyvinyl butyral; Terpene resin; Coumarone indene resin; Petroleum resin can be used. Preferred binders include styrene copolymers and polyester resins.

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

In the present invention, TH of the binder resin of the toner is
The number average molecular weight of the F-soluble component is 3,000 to 1,000,000.
00 is preferably 5,000 to 200,000.

The styrene-based polymer or styrene-based copolymer may be crosslinked, or may be a mixed resin of a crosslinked resin and a noncrosslinked resin.

As the crosslinking agent for the binder resin, a compound having mainly two or more polymerizable double bonds may be used. For example, aromatic divinyl compounds such as divinylbenzene and divinylnaphthalene; carboxylic acid esters having two double bonds such as ethylene glycol diacrylate, ethylene glycol dimethacrylate, and 1,3-butadiol dimethacrylate; Divinyl compounds such as, divinylaniline, divinylether, divinylsulfide, divinylsulfone; and 3
Compounds having at least two vinyl groups are used alone or as a mixture.

The amount of the cross-linking agent to be added is as follows.
0.001 to 10 parts by weight based on 00 parts by weight is preferred.

The toner of the present invention may contain a charge control agent.

The following substances control the toner to be negatively charged.

For example, an organic metal compound and a chelate compound are effective, and a monoazo metal compound, an acetylacetone metal compound, an aromatic hydroxycarboxylic acid, and an aromatic dicarboxylic acid metal compound are preferably used. Further, aromatic hydroxycarboxylic acids, aromatic mono- and polycarboxylic acids and their metal salts, their anhydrides, their esters, their phenol derivatives such as bisphenol; urea derivatives; metal-containing salicylic acid-based compounds; Metal naphthoic acid compound; boron compound;
Quaternary ammonium salts; calixarenes; silicon compounds; styrene-acrylic acid copolymers; styrene-methacrylic acid copolymers; styrene-acrylic-sulfonic acid copolymers; and nonmetal carboxylic acid compounds.

The following substances control the toner to be positively charged.

For example, analogs of nigrosine; denatured products with fatty acid metal salts; guanidine compounds; imidazole compounds; quaternary ammonium salts such as tributylbenzine ammonium-1-hydroxy-4-naphthosulfonate and tetrabutylammonium tetrafluoroborate. Lake pigments of onium salts such as phosphonium salts and quaternary ammonium salts or onium salts; triphenylmethane dyes and these lake pigments (for example, phosphotungstic acid, phosphomolybdic acid, phosphotungsten molybdic acid , Tannic acid, lauric acid, gallic acid, ferricyanide, ferrocyanide;
Metal salts of higher fatty acids; diorganotin oxides such as dibutyltin oxide, dioctyltin oxide and dicyclohexyltin oxide; and diorganotin borates such as dibutyltin borate, dioctyltin borate and dicyclohexyltin borate.
These can be used alone or in combination of two or more. Among these, a charge control agent such as a nigrosine-based or quaternary ammonium salt is particularly preferably used from the viewpoint of good charge rising.

These charge control agents are used in an amount of 0.01 to 20 parts by weight, preferably 0.1 to 10 parts by weight, and more preferably 0.1 to 10 parts by weight, based on 100 parts by weight of the resin component of the toner.
It is preferable to use 2 to 4 parts by weight.

As the colorant of the toner used in the present invention, a black colorant which is toned to black using carbon black, a magnetic substance, a yellow colorant, a magenta colorant or a cyan colorant shown below is used. You.

As the yellow colorant, a condensed azo compound, an isoindolinone compound, an anthraquinone compound,
An azo metal complex, a methine compound and an allylamide compound are used. Specifically, C.I. I. Pigment Yellow 12, 13, 14, 15, 17, 62, 74, 83, 9
3, 94, 95, 109, 110, 111, 128, 1,
29, 147, 168 or 180 is preferably used.

Examples of the magenta coloring agent include condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinones, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds and perylene compounds. Specifically, C.I. I
Pigment Red 2, 3, 5, 6, 7, 23, 48;
2, 48; 3, 48; 4, 57; 1, 81; 1, 14
4, 146, 166, 169, 177, 184, 18
5, 202, 206, 220, 221 or 254 are preferably used.

As the cyan coloring agent, a copper phthalocyanine compound and its derivative, an anthraquinone compound and a basic dye lake compound are used. Specifically, C.I. I. Pigment Blue 1, 7, 15, 15: 1, 15: 2, 1
5: 3, 15: 4, 60, 62 or 66 can be particularly preferably used. These colorants can be used alone, in a mixture or in a solid solution state. In the present invention, the colorant is selected in consideration of hue angle, saturation, lightness, weather resistance, OHP transparency, and dispersibility in a toner.
In the toner used in the present invention, the amount of the colorant is preferably 1 to 20 parts by weight based on 100 parts by weight of the resin.

Further, in the present invention, the toner can be used as a magnetic toner further containing a magnetic material. In this case, the magnetic material can also serve as a colorant.

In the present invention, examples of the magnetic material contained in the magnetic toner include iron oxides such as magnetite, hematite, and ferrite; metals such as iron, cobalt, and nickel; and metals such as aluminum, cobalt, copper, and the like. Lead, magnesium, tin, zinc, antimony,
Alloys with metals such as beryllium, bismuth, cadmium, calcium, manganese, selenium, titanium, tungsten, vanadium and mixtures thereof.

The magnetic material used in the present invention is more preferably surface-modified. When a magnetic toner is obtained by a polymerization toner production method, it is preferable to modify the surface with a surface modifier that is a substance that does not inhibit polymerization of the polymerizable monomer. Examples of such a surface modifier include silane cups. Ring agents and titanium coupling agents can be mentioned.

The ferromagnetic material as these magnetic materials preferably has an average particle size of 2 μm or less, more preferably 0.1 μm or less.
It is preferably about 0.5 μm.

The amount of the magnetic material contained in the magnetic toner is preferably 10 to 2 parts per 100 parts by weight of the resin component.
00 parts by weight, more preferably 20 to 100 parts by weight.

As the wax to be contained in the toner of the present invention, gel permeation chromatography (GP
In the molecular weight distribution measured by C), the weight average molecular weight (Mw) / number average molecular weight (Mn) is 1.45 or less, and the solubility parameter is 8.4 to 10.5.
It is preferred that By using such a wax, the toner is excellent in fluidity, a uniform fixed image without gloss unevenness can be obtained, and furthermore, contamination and deterioration of preservation of the heating member of the fixing device are hardly caused, and the fixing property and the fixing property are fixed. When a full-color OHP with excellent transparency and excellent transparency is produced by melting the toner, a part or all of the wax moderately covers the heating member, and the toner is not offset, and the full-color OHP is not offset. Can be formed, good low-temperature fixability can be exhibited, and the life of the press-contact member can be extended.

When the value of Mw / Mn of the wax exceeds 1.45, the fluidity of the toner is reduced, so that the gloss unevenness of the fixed image is liable to occur. Contamination to members is likely to occur.

In the present invention, the molecular weight distribution of the wax is measured by GPC using a double column under the following conditions.

(GPC measurement conditions) Apparatus: GPC-150C (manufactured by Waters) Column: GMH-HT 30 cm double column (manufactured by Tosoh Corporation) Temperature: 135 ° C Solvent: o-dichlorobenzene (0.1% ionol added) Flow rate: 1.0 ml / min Sample: Inject 0.4 ml of 0.15% sample

Measurement is performed under the above conditions, and the molecular weight of the sample is calculated using a molecular weight calibration curve prepared from a monodisperse polyethylene standard sample. In addition, Mark-Hou
The molecular weight is calculated by converting to polyethylene using a conversion formula derived from the win viscosity formula.

The melting point of the wax used in the present invention is 3
The temperature is preferably from 0 to 150 ° C, more preferably from 50 to 120 ° C. The melting point of the wax is 3
When the temperature is lower than 0 ° C., the blocking resistance of the toner, the suppression of sleeve contamination at the time of copying a large number of sheets, and the prevention of contamination of the photoreceptor are likely to deteriorate. If the melting point of the wax exceeds 150 ° C., excessive energy is required for uniform mixing with the binder resin in the production of the toner by the pulverization method, and the homogenization of the binder resin in the production of the toner by the polymerization method is also required. In addition, since the size of the apparatus is increased due to the increase in viscosity or the amount of compatibility is limited, it is not preferable because it becomes difficult to contain a large amount.

In the present invention, the melting point of the wax is AS
The temperature was defined as a temperature of a main peak value in an endothermic curve measured according to TM D3418-8.

For the measurement according to ASTM D3418-8, for example, DSC-7 manufactured by Perkin Elmer Co., Ltd. is used. The temperature correction of the device detection unit uses the melting points of indium and zinc, and the heat quantity correction uses the heat of fusion of indium. An aluminum pan was used as a sample, an empty pan was set as a control, and the temperature was raised at a rate of 10 ° C./min. At a temperature in the range of 20 to 200 ° C.

The melt viscosity at 100 ° C. of the wax used in the present invention is preferably 1 to 50 mpa · s, more preferably 3 to 30 mpa · s.
A wax compound having sec is particularly preferred.

The melt viscosity of the wax is 1 mpa · sec.
If it is lower, when the toner layer is thinly coated on the sleeve by a toner layer thickness regulating member that regulates the toner layer thickness by an elastic force such as an elastic blade in a one-component developing method, the sleeve is contaminated by mechanical shearing force. When the toner is developed using the carrier in the two-component developing method, the toner tends to be damaged due to the shear force between the toner and the carrier, and the external additive is easily buried or the toner is crushed. When the melt viscosity of the wax exceeds 50 mPas · sec, it is easy to obtain a toner having a fine particle size having a uniform particle size because the viscosity of the dispersoid is too high when a toner is produced using a polymerization method. And the toner tends to have a wide particle size distribution.

In the present invention, the melt viscosity of the wax can be measured by using a cone plate type rotor (PK-1) with VT-500 manufactured by HAAKE.

Further, the wax used in the present invention is:
The molecular weight distribution measured by GPC has two or more peaks or one or more peaks and one or more shoulders, and the weight average molecular weight (M
w) is 200 to 2000, and the number average molecular weight (Mn) is 1
Preferably it is 50 to 2000. More preferably, Mw is 200 to 1500, further preferably 300
And Mn is preferably 200 to 1500, and more preferably 250 to 1000. If the Mw of the wax is less than 200 and the Mn is less than 150, the blocking resistance of the toner decreases. If the Mw of the wax exceeds 2,000 and the Mn of the wax exceeds 2,000, the crystallinity of the wax itself develops, and the transparency decreases. It has been found that the above-mentioned molecular weight distribution can be achieved with either a single wax or a plurality of waxes, and as a result, crystallinity can be inhibited and transparency can be further improved. The method of blending two or more waxes is not particularly limited. For example, a media-type dispersing machine (ball mill, sand mill, attritor, apex mill, co-ball mill, handy mill) at a temperature equal to or higher than the melting point of the wax to be blended.
Can be used for melt blending, or the wax to be blended can be dissolved in a polymerizable monomer and blended with a media type disperser. At this time, a pigment, a charge control agent, and a polymerization initiator may be used as additives.

The wax is used in an amount of 1 to 40 parts by weight, preferably 2 to 30 parts by weight, based on 100 parts by weight of the binder resin of the toner.

In a pulverized toner production method in which a mixture containing a binder resin, a colorant and a wax is melt-kneaded, cooled, pulverized and then classified to obtain toner particles, the amount of wax added is as follows.
It is preferable to use 1 to 10 parts by weight, more preferably 2 to 7 parts by weight, based on 100 parts by weight of the binder resin.

In a polymerization toner production method in which toner particles are directly obtained by superimposing a mixture containing a polymerizable monomer, a colorant and a wax, the amount of the wax added depends on the amount of the polymerizable monomer or the polymerizable polymer. 2 to 40 parts by weight based on 100 parts by weight of the resin synthesized by polymerization of the reactive monomer,
More preferably 5 to 30 parts by weight, further preferably 10
It is preferred to use up to 20 parts by weight.

Compared to the pulverized toner production method, in the polymerization toner production method, the wax used is lower in polarity than the binder resin, and the polymerization method in an aqueous medium makes it easy to encapsulate a large amount of wax inside the toner particles. In comparison, a large amount of wax can be used, which is particularly effective for the effect of preventing offset during fixing.

If the amount of the wax is less than the lower limit, the effect of preventing offset tends to decrease, and if it exceeds the upper limit, the anti-blocking effect is reduced and the anti-offset effect is liable to be adversely affected. In particular, in the case of a polymerization toner production method, a toner having a wide particle size distribution tends to be produced.

Examples of the wax that can be used in the present invention include paraffin wax, polyolefin wax, modified products thereof (eg, oxides and graft-treated products), higher fatty acids, metal salts thereof, and amide waxes. And ester-based waxes.

Among them, higher quality full color OHP
Ester wax is particularly preferred in that an image can be obtained.

As the method for producing the ester wax preferably used in the present invention, for example, a synthesis method by an oxidation reaction, a synthesis from a carboxylic acid or a derivative thereof, and an ester group introduction reaction represented by a Michael addition reaction are used.

A particularly preferred method for producing the wax used in the present invention is a method utilizing a dehydration condensation reaction of a carboxylic acid compound represented by the following formula (1) and an alcohol compound, from the viewpoint of variety of raw materials and ease of reaction. The reaction of a halide represented by the formula (2) with an alcohol compound is particularly preferred.

[0128]

[Outside 2] In the formula, R ₁ and R _{2 each} represent an organic group such as an alkyl group, an alkenyl group, an aralkyl group and an aromatic group, and n represents an integer of 1 to 4. The organic group has 1 to 50 carbon atoms, preferably 2 to 2 carbon atoms.
More preferably, it is 4 to 30, more preferably 45, and more preferably linear.

In order to transfer the above-mentioned ester equilibrium reaction to the production system, a large excess of alcohol is used, or the reaction is carried out in an aromatic organic solvent capable of azeotropic distillation with water using a Dean-Stark water separator. . A method of synthesizing a polyester by adding a base as an acceptor of an acid by-produced in an aromatic organic solvent using an acid halide compound can also be used.

Additives for imparting various toner properties should have a particle size of not more than 1/5 of the volume average particle size of the toner particles from the viewpoint of durability when added to the toner or externally added to the toner. Is preferred. The particle size of the additive means an average particle size obtained by observing the surface of the toner particles with an electron microscope. The toner according to the present invention preferably has an externally added additive, and the additive has a shape factor SF1 on the toner of 150 or more, preferably greater than 180, and more preferably greater than 200. Is effective in suppressing burial on the toner surface. As additives for imparting these properties, for example, the following are used.

Examples of the fluidity-imparting agent include metal oxides such as silicon oxide, aluminum oxide and titanium oxide;
Carbon black; and carbon fluoride.
Each of these is preferably subjected to a hydrophobic treatment.

Examples of the abrasive include metal oxides such as strontium titanate, cerium oxide, aluminum oxide, magnesium oxide and chromium oxide; nitrides such as silicon nitride; carbides such as silicon carbide; and calcium sulfate and sulfuric acid. Metal salts such as barium and calcium carbonate are mentioned.

Examples of the lubricant include fluororesin powders such as vinylidene fluoride and polytetrafluoroethylene, and fatty acid metal salts such as zinc stearate and calcium stearate.

Examples of the charge control particles include tin oxide,
Metal oxides such as titanium oxide, zinc oxide, silicon oxide and aluminum oxide; and carbon black.

These additives are preferably used in an amount of 0.1 to 10 parts by weight, more preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the toner particles. These additives may be used alone or in combination of two or more.

Next, a method for producing the toner used in the present invention will be described. The toner used in the present invention can be manufactured using a pulverized toner manufacturing method and a polymerized toner manufacturing method.

In the present invention, a method for producing a pulverized toner includes a binder resin, a wax, a pigment as a colorant, a dye or a magnetic material, a charge control agent, and other additives as necessary, such as a Henschel mixer and a ball mill. The resulting mixture is melt-kneaded using a hot kneader such as a heating roll, kneader, extruder and the like, and the metal components, pigments, dyes, and magnetic materials are mixed while the resin components are mutually compatible. The resulting kneaded product is cooled and solidified, and then pulverized and classified to obtain a toner.

Further, if necessary, the toner and the desired additives are sufficiently mixed by a mixer such as a Henschel mixer.
The toner used in the present invention can be obtained.

In the present invention, a method for producing a polymerized toner is, for example, a method for obtaining spherical toner particles by atomizing a molten mixture into air using a disk or a multi-fluid nozzle described in JP-B-56-13945; Japanese Patent Publication No. 36-
No. 10231, JP-A-59-53856 and JP-A-59-61842, in which toner particles are directly produced using a suspension polymerization method; An emulsion polymerization method typified by a dispersion polymerization method of directly producing toner particles using an aqueous organic solvent in which the resulting polymer is unnecessary or a soap-free polymerization method of directly polymerizing in the presence of a water-soluble polar polymerization initiator to produce toner particles; A method in which a primary polar emulsion polymerized particle is prepared in advance, and then a polar particle having an opposite charge is added thereto to produce a toner by a heteroaggregation method in which the particles are associated with each other.

Of these, a method in which toner particles are produced by directly polymerizing a monomer composition containing at least a polymerizable monomer, a colorant and a wax is preferred.

However, in the dispersion polymerization method, the obtained toner shows an extremely sharp particle size distribution, but the selection of materials to be used is narrow, and the use of an organic solvent has an effect on the treatment of waste solvent and the flammability of the solvent. From the viewpoint, the manufacturing apparatus is complicated and complicated. Therefore, a method of directly polymerizing a monomer composition containing at least a polymerizable monomer, a colorant and a wax in an aqueous medium to form toner particles is more preferable. However, the emulsion polymerization method represented by soap-free polymerization is effective because the particle size distribution of the toner is relatively uniform, but when the used emulsifier and the terminal of the initiator are present on the surface of the toner particles, the environmental characteristics are likely to deteriorate.

Accordingly, in the present invention, the suspension polymerization method under normal pressure or under pressure, which can easily obtain a fine particle toner having a sharp particle size distribution, is particularly preferable. Further, a so-called seed polymerization method in which a monomer is further adsorbed on the obtained polymer particles and then polymerized using a polymerization initiator can also be suitably used in the present invention.

A preferred form of the toner used in the present invention is a toner in which a wax is encapsulated in an outer resin layer by a tomographic plane measurement method using a transmission electron microscope (TEM). From the viewpoint of fixability, it is preferable to include wax in a large amount of wax toner in the outer shell resin layer from the viewpoint of storage stability and fluidity of the toner. When the toner is not included, the wax cannot be dispersed uniformly, and as a result, the particle size distribution is widened, and the toner is easily fused to the mounting. As a specific method of encapsulating the wax, the polarity of the material in the aqueous medium is set to be smaller for the wax than for the main monomer, and a small amount of a polar resin or monomer is further added. A so-called core in which wax is coated with an outer shell resin layer /
A toner having a shell structure can be obtained. Control of the particle size distribution and particle size of the toner can be achieved by changing the type or amount of a poorly water-soluble inorganic salt or dispersant that acts as a protective colloid; mechanical device conditions such as the peripheral speed of the rotor, the number of baths, Stirring conditions such as stirring blade shape or container shape or
By controlling the solid concentration in the aqueous solution, a predetermined toner of the present invention can be obtained.

In the present invention, a specific method for measuring the tomographic plane of the toner is to disperse the toner sufficiently in a cold-setting epoxy resin and then cure it in an atmosphere at a temperature of 40 ° C. for 2 days. The cured product is stained with ruthenium tetroxide or, if necessary, with osmium tetroxide, and then a flaky sample is cut out using a microtome with diamond teeth, and a transmission electron microscope (TEM) is performed. The tomographic morphology of the used toner was measured. In the present invention, it is preferable to use a ruthenium tetroxide dyeing method in order to give a contrast between materials by utilizing a slight difference in crystallinity between the wax used and the resin constituting the shell resin layer.

In the case where a direct polymerization method is used in the toner production method of the present invention, the toner can be specifically produced by the following production method. A wax, a colorant, a charge control agent, a polymerization initiator and other additives are added to the monomer, and a monomer system uniformly dissolved or dispersed by a homogenizer or a disperser such as an ultrasonic disperser is used as a dispersion stabilizer. Is dispersed in an aqueous phase containing the same using a conventional stirrer or a stirrer such as a homomixer or a homogenizer. Preferably, the stirring speed and time are adjusted so that the monomer droplets have the desired size of the toner particles, and the granulation is performed. After that, due to the action of the dispersion stabilizer, the particle state is maintained,
In addition, stirring may be performed to such an extent that settling of particles is prevented.
The polymerization is carried out at a polymerization temperature of 40 ° C. or higher, preferably 50 to 90 ° C. The temperature may be raised in the latter half of the polymerization reaction. The medium is preferably distilled off.
After completion of the reaction, the generated toner particles are collected by washing and filtration, and dried. In the suspension polymerization method, it is usually preferable to use 300 to 3000 parts by weight of water as a dispersion medium with respect to 100 parts by weight of the monomer system.

When a toner is directly obtained by a polymerization method, the polymerizable monomer may be a styrene-based monomer such as styrene, o (m-, P-)-methylstyrene, m (P-)-ethylstyrene. Body; methyl (meth) acrylate, (meth)
Ethyl acrylate, propyl (meth) acrylate, butyl (meth) acrylate, octyl (meth) acrylate,
(Meth) such as dodecyl (meth) acrylate, stearyl (meth) acrylate, behenyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, and diethylaminoethyl (meth) acrylate ) Acrylate-based monomers; ene-based monomers such as butadiene, isoprene, cyclohexene (meth) acrylonitrile and acrylamide are preferably used.

In the present invention, in order to form a core / shell structure in the toner, it is preferable to use a polar resin in combination. Examples of polar resins such as polar polymers and polar copolymers that can be used in the present invention are given below.

As the resin polarity, a polymer of a nitrogen-containing monomer such as dimethylaminoethyl methacrylate or diethylaminoethyl methacrylate or a copolymer of a nitrogen-containing monomer and a styrene-unsaturated carboxylic acid ester; acrylonitrile Nitrile monomers such as vinyl chloride; halogen-containing monomers such as vinyl chloride; unsaturated carboxylic acids such as acrylic acid and methacrylic acid; unsaturated dibasic acids; unsaturated dibasic acid anhydrides; A polymer or a copolymer of the polymer and a styrene monomer; a polyester; an epoxy resin. More preferred are a copolymer of styrene and (meth) acrylic acid, a maleic acid copolymer, a saturated polyester resin, and an epoxy resin.

Examples of the polymerization initiator include, for example, 2,2'-
Azobis- (2,4-dimethylvaleronitrile), 2,
2'-azobisisobutyronitrile, 1,1'-azobis (cyclohexane-1-carbonitrile), 2,2 '
Azo or diazo polymerization initiators such as azobis-4-methoxy-2,4-dimethylvaleronitrile and azobisisobutyronitrile; benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxycarbonate, cumene hydroperoxide, t-butylhydrogen Peroxide, di-t-butyl peroxide,
Peroxide initiators such as dixyl peroxide, 2,4-dichlorobenzoyl peroxide, lauroyl peroxide, 2,2-bis (4,4-t-butylperoxycyclohexyl) propane and tris- (t-butylperoxy) triazine A polymeric initiator having a peroxide in the side chain; persulfates such as potassium and ammonium persulfate; hydrogen peroxide; These can be used alone or in combination of two or more.

The polymerization initiator is preferably added in an amount of 0.5 to 20 parts by weight based on 100 parts by weight of the polymerizable monomer.

In the present invention, a known crosslinking agent or chain transfer agent may be added to control the molecular weight. The preferred addition amount is 0.001 to 15 parts by weight based on 100 parts by weight of the polymerizable monomer. Department.

In the present invention, a dispersion medium used for producing a polymerization toner by emulsion polymerization, dispersion polymerization, suspension polymerization, seed polymerization, or a polymerization method using a heteroaggregation method includes a suitable inorganic compound or organic compound. It is preferred to use a compound stabilizer. As a stabilizer for inorganic compounds,
For example, tricalcium phosphate, magnesium phosphate, aluminum phosphate, zinc phosphate, calcium carbonate, magnesium carbonate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, calcium metasilicate, calcium sulfate, barium sulfate, bentonite, silica And alumina. As stabilizers for organic compounds,
For example, polyvinyl alcohol, gelatin, methylcellulose, methylhydroxypropylcellulose, ethylcellulose, sodium salt of carboxymethylcellulose, polyacrylic acid and its salts, starch, polyacrylamide, polyethylene oxide, poly (hydroxystearic acid-g-methyl methacrylate-) (eu-methacrylic acid) copolymer and a nonionic or ionic surfactant.

When the emulsion polymerization method and the heteroaggregation method are used, an anionic surfactant, a cationic surfactant,
Zwitterionic surfactants and nonionic surfactants are used as stabilizers. It is preferable to use 0.2 to 30 parts by weight of these stabilizers based on 100 parts by weight of the polymerizable monomer.

When an inorganic compound is used among these stabilizers, a commercially available one may be used as it is. However, in order to obtain fine particles, the inorganic compound stabilizer is formed in a dispersion medium. Is also good.

In order to finely disperse these stabilizers, a surfactant may be used in an amount of 0.001 to 0.1 part by weight based on 100 parts by weight of the polymerizable monomer. This surfactant is for promoting the stabilizing action of the dispersion stabilizer. Specific examples of the surfactant include sodium dodecylbenzene sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, sodium oleate, sodium laurate, potassium stearate, and calcium oleate.

In the present invention, as the colorant used in the polymerization method toner, it is necessary to pay attention to the polymerization inhibitory property and the water phase migration property of the colorant. It is better to perform a hydrophobic treatment without any. In particular, many dyes and carbon blacks have polymerization inhibitory properties, so care must be taken when using them.
A preferred method of surface-treating the dye system includes a method in which a polymerizable monomer is previously polymerized in the presence of these dyes.For carphocene black in which the obtained colored polymer is added to the monomer system, In addition to the same treatment as the above dye, treatment with a substance that reacts with the surface functional group of carbon black, such as polyorganosilixane, may be performed.

Furthermore, the melting point of the wax of the toner is higher than the glass transition temperature of the binder resin, and the temperature difference is preferably 100 ° C. or less, more preferably 75 ° C. or less, and further preferably 50 ° C. or less. .

When the temperature difference exceeds 100 ° C.,
The low-temperature fixability decreases. Furthermore, if this temperature difference is too close, the temperature range in which both the storability of the toner and the high-temperature offset resistance are compatible is narrowed. Therefore, the temperature difference is preferably 2 ° C. or more. The glass transition temperature of the binder resin is preferably from 40 ° C. to 90 ° C., more preferably 5 ° C.
The temperature is preferably 0 to 85 ° C.

When the glass transition temperature of the binder resin is lower than 40 ° C., the storage stability of the toner is lowered and the fluidity is deteriorated, so that a good image cannot be obtained.

When the glass transition temperature of the binder resin exceeds 90 ° C., the low-temperature fixing property is inferior, and the transparency of full-color transparency is deteriorated. In particular, the halftone portion tends to be dull and a projection image without saturation is likely to be obtained.

In the present invention, the glass transition temperature (Tg) of the binder resin was measured by a measurement according to ASTM D3418-8. For example, PerkinElmer DS
This is performed using C-7. The temperature correction of the device detection unit uses the melting points of indium and zinc, and the heat quantity correction uses the heat of fusion of indium. For the sample, an aluminum pan was used, an empty pan was set for control, and the temperature was raised at a rate of 10 ° C / mi.
n. At a temperature in the range of 20 to 200 ° C.

As the developing method of the present invention, for example, development can be performed using a developing means as shown in FIG. Specifically, it is preferable to perform the development while the magnetic brush is in contact with the latent image carrier, for example, the photosensitive drum 3 while applying an alternating electric field. Developer carrier (developing sleeve)
The distance B between the photoconductor drum 3 and the photosensitive drum 3 (distance between SD) is 100.
A thickness of from 1000 to 1000 μm is favorable in preventing carrier adhesion and improving dot reproducibility. If it is smaller than 100 μm, the supply of the developer tends to be insufficient, and the image density becomes low. If it exceeds 1000 μm, the lines of magnetic force from the developer S1 are widened, the density of the magnetic brush becomes low, and the dot reproducibility becomes poor, The force for restraining the carrier is weakened, and carrier adhesion is likely to occur.

The voltage between the peaks of the alternating electric field is 300 to 30
00V is preferable, the frequency is 500 to 10000 Hz,
Preferably, it is 1000-7000 Hz, and each can be appropriately selected and used depending on the process. In this case, the waveform may be triangular, rectangular, sine, or D
Various selections such as a waveform with a changed duty ratio and an intermittent alternating electric field superposition can be used. When the applied voltage is 300
If it is lower than V, it may be difficult to obtain a sufficient image density, and it may not be possible to satisfactorily collect the fog toner in the non-image area. If the voltage exceeds 3000 V, the latent image may be disturbed via the magnetic brush, and the image quality may be degraded.

By using a two-component developer having a well-charged toner, the fog removal voltage (Vback)
And the primary charge of the photoconductor can be reduced, so that the life of the photoconductor can be extended. Vbac
k is preferably 200 V or less, more preferably 150 V or less, depending on the developing system.

As the contrast potential, 100 V to 400 V is preferably used so that a sufficient image density can be obtained.

When the frequency is lower than 500 Hz, although it is related to the process speed, an oscillating electric field sufficient to return the toner in contact with the photoreceptor to the developing sleeve is not given.
Fog tends to occur. If the frequency exceeds 10,000 Hz, the toner cannot follow the electric field, and the image quality is likely to deteriorate.

What is important in the developing method of the present invention is that the photosensitive drum 3 of the magnetic brush on the developing sleeve 1 is used to obtain a sufficient image density, have excellent dot reproducibility, and perform development without carrier adhesion. Is preferably set to 3 to 8 mm. Development nip C is 3
If the width is smaller than 8 mm, it is difficult to sufficiently satisfy the sufficient image density and dot reproducibility. If the width is larger than 8 mm, the packing of the developer occurs and the operation of the machine is stopped, and the adhesion of the carrier is sufficiently suppressed. It is difficult to support. As a method of adjusting the developing nip, the nip width is appropriately adjusted by adjusting the distance A between the developer regulating member 2 and the developing sleeve 1 or adjusting the distance B between the developing sleeve 1 and the photosensitive drum 3.

The image forming method of the present invention uses three or more developing units for magenta, cyan, and yellow, especially in the output of a full-color image in which halftone is emphasized. And using a developing method,
In particular, by combining with a developing system that forms a digital latent image, it is possible to develop the dot latent image faithfully without being affected by the magnetic brush and disturbing the latent image. Also in the transfer step, a high transfer rate can be achieved by using a finely-cut toner having a sharp particle size distribution, so that high image quality can be achieved in both the halftone portion and the solid portion.

Furthermore, by using the two-component developer of the present invention together with the initial improvement in image quality, the share of the developer in the developing device is small, and the present invention does not cause a deterioration in image quality even when copying a large number of sheets. The effect of can be fully exhibited.

In order to obtain a tighter image, it is preferable to have a developing device for magenta, cyan, yellow, and black, and to exhibit a tighter image by performing black development last. it can.

Next, an example of the image forming method of the present invention will be described more specifically with reference to FIG.

FIG. 3 is a schematic diagram showing an example of an image forming apparatus capable of performing the image forming method of the present invention.

This image forming apparatus is configured as a full-color copying machine. As shown in FIG. 3, the full-color copying machine has a digital color image reader unit 135 at the top and a digital color image printer unit 136 at the bottom.

In the image reader section, the original 130 is placed on the original platen glass 131, and is exposed and scanned by the exposure lamp 132, so that the reflected light image from the original 130 is condensed on the full-color sensor 134 by the lens 133 and is Obtain a decomposed image signal. The color-separated image signal is processed by a video processing unit (not shown) through an amplifier circuit (not shown) and sent to a digital image printer unit.

In the image printer section, a photosensitive drum 91 as a latent image holding member is a photosensitive member such as an organic photoconductor, and is rotatably supported in the direction of the arrow. Around the photosensitive drum 91, a pre-exposure lamp 111, a corona charger 92 as a primary charging member, a laser exposure optical system 93 as a latent image forming means, a potential sensor 112, four developing devices 94Y of different colors, 94C, 94M, 94K, on-drum light amount detecting means 113, transfer device 95A, and cleaning device 96 are arranged.

In the laser exposure optical system 93, an image signal from the reader section is converted into an image scan exposure light signal by a laser output section (not shown), and the converted laser light is reflected by the polygon mirror 93a. , Lens 93b
And is projected onto the surface of the photosensitive drum 91 via the mirror 93c.

[0177] When an image is formed, the photosensitive drum 9
1 is rotated in the direction of the arrow, and after the charge is removed by the pre-exposure lamp 111, the photosensitive drum 91 is uniformly negatively charged by the charger 92 to irradiate a light image E for each of the separated colors. Form an image.

Next, the latent image on the photosensitive drum 91 is developed by operating a predetermined developing device, and a visible image, that is, a toner image is formed on the photosensitive drum 91 by using a resin-based negative toner. Developing units 94Y, 94C, 94M, 94K
Are the respective eccentric cams 124Y, 124C, 124
By the operations of M and 124K, development is performed by selectively approaching the photosensitive drum 91 in accordance with each separation color.

The transfer device 95A includes a transfer drum 95, a transfer charger 95b, a suction charger 95c for electrostatically attracting a recording material and a suction roller 95g opposed thereto, an inner charger 95d, an outer charger 95e, Separation charger 95
h. The transfer drum 95 is rotatably supported so as to be rotatable, and a transfer sheet 95f, which is a recording material carrier that carries a recording material in an opening area around the transfer drum 95, is integrally adjusted on a cylinder. A polycarbonate film or the like is used for the transfer sheet 95f.

The recording materials are recording material cassettes 97a and 97b.
Or 97c from the transfer drum 95 through the recording material conveying system.
And is carried on the transfer sheet 95f. The recording material carried on the transfer drum 95 is
The toner image on the photosensitive drum 91 is transferred onto the recording material by the action of the transfer charger 95b while passing through the transfer position with the rotation of the photosensitive drum 91.

The above-described image forming step is performed by using yellow (Y),
By repeating the process for magenta (M), cyan (C), and black (K), a color image is obtained in which four color toner images are transferred onto the recording material on the transfer drum 95 in a superimposed manner.

In the case of single-sided image formation, the recording material onto which the four color toner images have been transferred in this manner is separated from the separation claw 98a,
The toner is separated from the transfer drum 95 and sent to the heat fixing device 99 by the action of the separation push-up roller 98b and the separation charger 95h. The heat fixing device 99 includes a heat fixing roller 99a having a heating unit therein and a pressure roller 99b. The full-color image carried on the recording material is fixed to the recording material by passing the recording material through the pressure contact portion between the heat fixing roller 99a and the pressure roller 99b as a heating member. That is, in this fixing step, toner color mixing, color development and fixing to the recording material are performed,
After being converted into a full-color permanent image, the sheet is discharged to the tray 110 and one full-color copy is completed. On the other hand, the photosensitive drum 1 is subjected to the image forming process again after the residual toner on the surface is cleaned and removed by the cleaning device 96.

In the image forming method of the present invention, a toner image obtained by developing the electrostatic latent image formed on the latent image holding member can be transferred to a recording material via an intermediate transfer member.

That is, in this image forming method, the toner image formed by developing the electrostatic latent image formed on the latent image holding member is transferred to the intermediate transfer member, and the toner image transferred to the intermediate transfer member is Is transferred to a recording material.

An example of an image forming method using an intermediate transfer member will be specifically described with reference to FIG.

In the apparatus system shown in FIG. 4, the cyan developing device 254-1, the magenta developing device 254-2, the yellow developing device 254-3, and the black developing device 254-4 are provided with a cyan developer containing a cyan toner and a magenta developer, respectively. A magenta developer having a toner, a yellow developer having a yellow toner, and a black developer having a black toner have been introduced. An electrostatic latent image is formed on a photosensitive member 251 as a latent image holding member by a latent image forming means 253 such as a laser beam. An electrostatic charge image formed on the photoconductor 251 is developed by using a developer such as a magnetic brush development system, a non-magnetic one-component development system, or a magnetic jumping development system.
1 is formed. The photosensitive member 251 is a photosensitive drum or a photosensitive belt having a conductive substrate 251b and a photoconductive insulating material layer 251a such as amorphous selenium, magnetized cadmium, zinc oxide, an organic photoconductor, and amorphous silicon formed on the conductive substrate 251b. is there. The photoconductor 251 is rotated in a direction indicated by an arrow by a driving device (not shown). As the photoconductor 251, a photoconductor having an amorphous silicon photosensitive layer or an organic photosensitive layer is preferably used.

As the organic photosensitive layer, either a single layer type in which the photosensitive layer contains a charge generating substance and a substance having a charge transporting property in the same layer, or a function-separated type photosensitive layer comprising the charge transporting layer and the charge generating layer as components. It may be. A laminated photosensitive layer having a structure in which a charge generation layer and then a charge transport layer are laminated on a conductive substrate in this order is one of preferred examples.

As the binder resin for the organic photosensitive layer, a polycarbonate resin, a polyester resin, or an acrylic resin has good cleaning properties, and poor cleaning, toner fusion to the photoreceptor, and filming hardly occur.

In the present invention, in the charging step, there are a non-contact type with the photosensitive member 251 using a corona charger and a contact type with a contact charging member such as a roller, and both types are used. Efficient uniform charging,
For simplicity and low ozone generation, a contact type system as shown in FIG. 4 is preferably used.

A charging roller 252 as a primary charging member
Is basically composed of a central metal core 252b and a conductive elastic layer 252a forming an outer periphery. Charging roller 2
52 is pressed against the surface of the photoconductor 251 with a pressing force,
The photosensitive member 251 rotates following the rotation of the photosensitive member 251.

The preferable process conditions when the charging roller is used are that the contact pressure of the roller is 5 to 500 g /
cm, when a voltage obtained by superimposing an AC voltage on a DC voltage is used, AC voltage = 0.5 to 5 kVpp, AC frequency =
50 Hz to 5 kHz, DC voltage = ± 0.2 to ± 5 kV.

Other contact charging members include a method using a charging blade and a method using a conductive brush. These contact charging members have the effects of eliminating the need for high voltage and reducing the generation of ozone.

The material of the charging roller and the charging blade as the contact charging member is preferably conductive rubber, and a release coating may be provided on the surface thereof. As the release coating, a nylon resin, PVDF (polyvinylidene fluoride), PVDC (polyvinylidene chloride), or a fluorine acrylic resin can be used.

The voltage of the toner image on the photosensitive member (for example, ± 0.
(± 1 kV) is applied to the intermediate transfer member 255 to which the voltage is applied. The intermediate transfer member 255 is a pipe-shaped conductive core 2
55b and a medium-resistance elastic layer 255a forming the outer peripheral surface thereof
Consists of The core metal 255b may be one in which a conductive layer (for example, conductive plating) is provided on the surface of plastic.

The medium resistance elastic layer 255a is made of silicone rubber, Teflon rubber, chloroprene rubber, urethane rubber,
Elastic materials such as EPDM (ethylene-propylene-diene terpolymer) include carbon black, zinc oxide,
This is a solid or foamed layer in which a conductivity imparting agent such as tin oxide or silicon carbide is mixed and dispersed to adjust the electric resistance (volume resistivity) to a medium resistance of 10 ⁵ to 10 ¹¹ Ωcm.

The intermediate transfer member 255 is arranged in parallel with the photosensitive member 251 so as to be in contact with the lower surface of the photosensitive member 251 and rotates counterclockwise at the same peripheral speed as the photosensitive member 251. I do.

In the process in which the toner image of the first color formed and carried on the surface of the photoconductor 251 passes through the transfer nip where the photoconductor 251 and the intermediate transfer member 255 are in contact with each other, the transfer nip is applied by the transfer bias applied to the intermediate transfer member 255. The intermediate transfer is sequentially performed on the outer surface of the intermediate transfer body 255 by the electric field formed in the intermediate transfer member 255.

The untransferred toner on the photosensitive member 251 that has not been transferred to the intermediate transfer member 255 is cleaned by the photosensitive member cleaning member 258 and collected in the photosensitive member cleaning container 259.

A transfer means is provided in parallel with the intermediate transfer body 255 and is brought into contact with the lower surface of the intermediate transfer body 255. The transfer means is, for example, a transfer roller 257 and has the same circumference as the intermediate transfer body 255. Rotate in the clockwise direction of the arrow at speed. The transfer roller 257 is a direct intermediate transfer member 255
, Or a belt or the like may be arranged to contact between the intermediate transfer member 255 and the transfer roller 257.

[0200] The transfer roller 257 has a central core metal 257b.
And a conductive elastic layer 257a having an outer periphery thereof.

As the intermediate transfer member and the transfer member used in the present invention, general materials can be used.
In the present invention, the voltage applied to the transfer member can be reduced by setting the volume resistivity of the transfer member smaller than the volume resistivity of the intermediate transfer member, and a good toner image can be formed on the transfer material and the transfer can be performed. The material can be prevented from winding around the intermediate transfer member. In particular, it is preferable that the volume resistivity of the elastic layer of the intermediate transfer member is at least 10 times higher than the volume resistivity of the elastic layer of the transfer member.

The hardness of the intermediate transfer member and the transfer member is determined according to JIS.
It is measured according to K-6301. The intermediate transfer member used in the present invention is preferably composed of an elastic layer belonging to the range of 10 to 40 degrees. The hardness of the elastic layer of the transfer member used in the present invention is higher than the hardness of the elastic layer of the intermediate transfer member, and preferably has a value of 41 to 80 degrees in order to prevent the recording material from winding around the intermediate transfer member. . If the hardness of the elastic layer of the transfer member is lower than the hardness of the elastic layer of the intermediate transfer member, a concave portion is formed on the transfer member side, and the recording material is likely to be wound around the intermediate transfer member.

As the transfer member, for example, a transfer roller is used, and the transfer roller 257 is rotated at a constant speed or at a different peripheral speed from the intermediate transfer member 255. Recording material 2
56 is transferred between the intermediate transfer member 255 and the transfer roller 257, and at the same time, a bias having a polarity opposite to that of the triboelectric charge of the toner is applied to the transfer roller 257 from the transfer bias unit, so that the toner on the intermediate transfer member 255 The image is transferred to the front side of the recording material 256.

The transfer residual toner on the intermediate transfer member that has not been transferred to the recording material 256 is cleaned by the cleaning member 260 for the intermediate transfer member and collected in the cleaning container 262 for the intermediate transfer member. The toner image transferred to the recording material 256 is heated and fixed by the heat fixing device 261.
Is established.

As the material of the transfer roller, the same material as that of the charging roller can be used. The preferable transfer process condition is that the contact pressure of the roller is 2.94 to 49.
0 N / m (3-500 g / cm) (more preferably 1
9.6 N / m to 294 N / m) and DC voltage = ± 0.2 to
± 10 kV.

When the linear pressure as the contact pressure is less than 2.94 N / m, it is not preferable because the conveyance of the recording material and the occurrence of transfer failure tend to occur.

For example, the conductive elastic layer 257b of the transfer roller 257 may be made of an elastic material such as polyurethane rubber or EPDM (ethylene propylene diene terpolymer), or a conductive imparting agent such as carbon black, zinc oxide, tin oxide or silicon carbide. Is mixed and dispersed to obtain an electric resistance value (volume resistivity) of 1
0 was adjusted to ⁶ to 10 ¹⁰ in the Ωcm resistivity is a layer of a solid or foamed meat.

[0208] Methods for measuring each physical property are described below.

The method for measuring the carrier particle size will be described.

The particle size of the magnetic coated carrier of the present invention was determined by randomly extracting 300 or more carrier particles having a particle size of 0.1 μm or more using an optical microscope (100 to 5,000 times) and analyzing the image by Nireco Co., Ltd. The horizontal Feret diameter was measured as the carrier particle diameter by a device Luzex3,
The number average particle size is calculated. Based on the number-based particle size distribution measured under these conditions, the cumulative ratio of the number average particle size smaller than 1/2 times the diameter cumulative distribution is determined, and the cumulative value equal to or smaller than the 1/2 size diameter cumulative distribution is calculated.

The magnetic properties of the magnetic coated carrier were measured by an oscillating magnetic field type automatic magnetic property recording apparatus BHV-3 manufactured by Riken Denshi Co., Ltd.
Measure using 0. The magnetic characteristic value of the magnetic coated carrier powder is determined by creating an external magnetic field of 1 kOe and determining the intensity of magnetization at that time. The magnetic coated carrier is manufactured in a state of being packed sufficiently in a cylindrical plastic container having a volume of about 0.07 cm ³ so as to be sufficiently dense. In this state, the magnetization moment is measured, the actual volume when the sample is placed is measured, and the magnetization intensity per unit volume is determined from this.

The electric resistance of the magnetic coated carrier or the carrier core is measured using a measuring device shown in FIG. Cell E
Is filled with a magnetic coated carrier or core, electrodes 31 and 32 are arranged so as to be in contact with the filled magnetic coated carrier or core, a voltage is applied between the electrodes, and a current flowing at that time is measured. Find the resistance value. In the above-mentioned measuring method, since the magnetic-coated carrier or the core is a powder, a change occurs in the filling rate, and accordingly, the electric resistance value may change, so that caution is required. The measurement conditions of the electric resistance value were as follows: the contact area S between the filled magnetic coat carrier or core and the electrode was about 2.3 cm ² , the thickness d was about 2 mm, the load of the upper electrode 22 was 180 g, and the applied voltage was 100.
V.

The method for measuring the particle size of the ferromagnetic compound and the nonmagnetic inorganic compound is described below. The number average particle diameter of the ferromagnetic compound and the non-magnetic inorganic compound was determined at random using a photographic image magnified 5000 to 20,000 times with a transmission electron microscope H-800 manufactured by Hitachi, Ltd.
300 or more of the above particles were extracted, and the particle size of the ferromagnetic compound and the nonmagnetic inorganic compound were measured with the Feret diameter in the horizontal direction using an image processing analyzer Luzex3 manufactured by Nireco Co., Ltd., and averaged to obtain a number average. Calculate the particle size.

The electric resistance of the ferromagnetic compound and the nonmagnetic inorganic compound is measured according to the method of Curia electric resistance. The cell E of FIG. 2 is filled with a ferromagnetic compound, a nonmagnetic inorganic compound, and a nonmagnetic inorganic compound, and electrodes 31 and 32 are arranged so as to be in contact with the filled ferromagnetic compound and nonmagnetic inorganic compound.
A voltage is applied between the electrodes, and the current flowing at that time is measured to determine the electric resistance. When filling the ferromagnetic compound and the non-magnetic inorganic compound, the filling is performed while rotating the upper electrode 31 left and right so that the electrode uniformly contacts the sample. In the above measuring method, the measuring conditions of the electric resistance are as follows:
The contact area S between the filled ferromagnetic compound and the non-magnetic inorganic compound and the electrode is about 2.3 cm ² , the thickness d is about 2 mm, the load on the upper electrode 32 is 180 g, and the applied voltage is 100 V.

Hereinafter, specific examples of the measurement of the toner particle size will be described.

To 100 to 150 ml of the electrolyte solution, 0.1 to 5 ml of a surfactant (alkylbenzene sulfonate) is added, and 2 to 20 mg of a measurement sample is added thereto. The electrolysis solution in which the sample was suspended was subjected to dispersion treatment for 1 to 3 minutes with an ultrasonic disperser, and the above described Coulter counter multisizer was used to adjust the volume of the electrolysis solution to an appropriate value of 17 μm or 100 μm using an aperture adjusted to the toner size. 3 ~
A particle size distribution of 40 μm is to be measured. The number average particle diameter and the weight average particle diameter measured under these conditions are obtained by computer processing, and the cumulative ratio of the number average particle diameter smaller than 1/2 times the diameter cumulative distribution is calculated from the number-based particle diameter distribution,
A cumulative value equal to or smaller than the 1/2 diameter cumulative distribution is obtained. Similarly, a cumulative ratio equal to or larger than the double diameter cumulative distribution of the weight average particle diameter is calculated from the volume-based particle size distribution, and a cumulative value equal to or larger than the double diameter cumulative distribution is obtained.

A method for measuring the triboelectric charge amount will be described.

The toner and the magnetic coated carrier were mixed so that the toner weight was 5% by weight, and mixed with a turbula mixer.
Mix for 0 seconds. This mixed powder (developer) is placed on the bottom at 500
It is placed in a metal container equipped with a mesh conductive screen, suction is performed with a suction device, and the amount of triboelectric charging is determined from the difference in weight before and after suction and the potential accumulated in a capacitor connected to the container. At this time, the suction pressure is set to 250 mmHg. With this method, the triboelectric charge amount is calculated using the following equation.

Q (μC / g) = (C × V) × (W ₁ −W ₂ ) ⁻¹ (where W ₁ is the weight before suction, W ₂ is the weight after suction, and C is The capacitance of the capacitor, and V is the potential stored in the capacitor.)

Hereinafter, the present invention will be described specifically with reference to examples, but the present invention is not limited to the examples.

[0221]

EXAMPLES (Manufacture example 1 of carrier) Phenol 50 parts by weight 37 parts by weight Formalin 75 parts by weight Melamine 5 parts by weight Water 50 parts by weight Titanium coupling agent-treated magnetite (particle diameter 0.24 μm, electric resistance value 5 × 10) ⁵ Ωcm, σs 70 emu / g) 350 parts by weight Titanium coupling agent-treated α-Fe ₂ O ₃ (particle diameter 0.6 μm, electric resistance value 8 × 10 ¹² Ωcm, σs0 emu / g) 150 parts by weight 28% ammonia water 15 Parts by weight was placed in a 1-liter four-necked flask and stirred for 40 minutes.
The temperature was maintained at 85 ° C. for 180 minutes, and the reaction and curing were performed for 180 minutes. After cooling to 30 ° C. and addition of 0.5 l of water, the supernatant was removed, the precipitate was washed with water and air-dried. Next, this was dried at 60 ° C. for 24 hours under reduced pressure (5 mmHg) to obtain a magnetic carrier core material A.

A coating layer was provided on the surface of the obtained core material by the following method.

A solution containing 5% by weight of aminopropyltrimethoxysilane was prepared using toluene as a solvent. While continuously applying shear stress to the solution, the toluene is volatilized to coat the carrier core material so that the treatment amount becomes 0.1% by weight, and the carrier core material surface is wetted with the silicone resin. Property modification.

Next, a carrier coat solution of 10% by weight of a silicone resin was prepared using toluene as a solvent. While continuously applying a shearing stress to the coating solution, the solvent was volatilized to coat the carrier core material with a treatment amount of 0.7% by weight. Thereafter, the mixture was cured at 140 ° C. for 2 hours, and after agglomerated, the particles were classified with a 200-mesh sieve to obtain a magnetic carrier I. The magnetic carrier I obtained had an SF1 of 108, a number average particle size of 28 μm, and an electric resistance value of 7.2.
The magnetization strength σ ₁₀₀₀ at × 10 ¹³ Ωcm and 1 kOe was 42 emu / g.

(Preparation Example 2 of Carrier) In Preparation Example 1, except that melamine I was not used, except that melamine I was not used, SF1 was 107 and the number average particle diameter was 29 μm.
m, electric resistance value is 1.3 × 10 ¹³ Ωcm, σ ₁₀₀₀ is 42
A magnetic carrier II having an emu / g was obtained.

(Carrier Production Example 3) In Carrier Example 1, except that the silicone resin was not coated,
A magnetic carrier III having an SF1 of 107, a number average particle size of 28 μm, an electric resistance value of 6.8 × 10 ¹² Ωcm, and σ ₁₀₀₀ of 42 emu / g was obtained.

(Preparation Example 4 of Carrier) The same procedure as in Preparation Example 1 was carried out except that urea was used instead of melamine. SF1 was 110, the number average particle diameter was 30 μm, and the electric resistance value was 3.5 × 10 ^13. Ωcm, σ ₁₀₀₀ is 42emu / g
Was obtained.

(Production Example 5 of Carrier) In Production Example 1, except that aminopropyltrimethoxysilane was not used, SF1 was 108 and the number average particle size was 28.
μm, electric resistance 5.3 × 10 ¹² Ωcm, σ ₁₀₀₀ 4
A magnetic carrier V of 2 emu / g was obtained.

(Preparation Example 6 for Carrier) In Preparation Example 1, 1 part by weight of phenol and 37% by weight of formalin 2.5
Parts by weight, except that it was changed to 0.1 parts by weight of melamine, α-Fe ₂ O ₃ could not be bound well,
No carrier particles were formed.

(Preparation Example 7 of Carrier) A magnetic carrier VI was prepared in the same manner as in Preparation Example 1, except that the amounts of phenol, 37% by weight formalin, and melamine were changed as follows. Phenol 300 parts by weight 37% by weight Formalin 450 parts by weight Melamine 30 parts by weight The magnetic carrier VI has an SF1 of 128 and an average particle size of 35.
μm, electric resistance value is 6.5 × 10 ¹⁴ Ωcm, σ ₁₀₀₀ is 3
It was 6 emu / g.

(Production Example 8 of Carrier) In the same manner as in Production Example 1, except that the stirring conditions were weakened and the temperature was raised for 60 minutes, SF1 was 113, the number average particle size was 110 μm, and the electric resistance was Value is 1.2 × 10 ¹⁴ Ωcm, σ
A magnetic carrier VII with ₁₀₀₀ of 41 emu / g was obtained.

(Carrier Production Example 9) In the same manner as in Production Example 1, except that the stirring conditions were increased and the temperature was raised in 25 minutes, SF1 was 115, the number average particle size was 4 μm, and the electric resistance was A magnetic carrier VIII having a value of 2.5 × 10 ¹⁰ Ωcm and σ ₁₀₀₀ of 42 emu / g was obtained.

(Preparation Example 10 of Carrier) In Preparation Example 1, Mg—Mn—fineness was reduced to 0.35 μm instead of magnetite, and then treated with a silane coupling agent.
Sr-Fe fine particles (electric resistance 5.9 × 10 ¹² Ωcm,
σ _s 63 emu / g).
A magnetic carrier IX having F1 of 109, a number average particle size of 31 μm, an electric resistance value of 6.3 × 10 ¹⁴ Ωcm, and σ ₁₀₀₀ of 45 emu / g was obtained.

(Preparation Example 11 of Carrier) In Preparation Example 1, except that a mixture of vinylidene fluoride / tetrafluoroethylene copolymer and styrene / methyl methacrylate copolymer was used in place of the silicone resin, SF1 is 108, number average particle size is 29 μm, electric resistance is 5.2 × 10 ¹³ Ωcm, σ ₁₀₀₀ is 42 emu
/ G of magnetic carrier X was obtained.

(Preparation Example 12 of Carrier) In Preparation Example 1, except that a non-reactive imidazole compound was used instead of melamine, SF1 was 113, the number average particle size was 32 μm, and the electric resistance value was 5.3 × 10 ¹² Ωc
A magnetic carrier XI having m and σ ₁₀₀₀ of 41 emu / g was obtained.

(Carrier Production Example 13) Phenol 50 parts by weight 37% formalin 75 parts by weight Water 50 parts by weight Titanium coupling agent-treated magnetite 350 parts by weight Titanium coupling agent-treated α-Fe ₂ O ₃ 150 parts by weight 28% ammonia 15 parts by weight of water is placed in a 1-liter four-necked flask, and stirred for 40 minutes.
The temperature was kept at 85 ° C. for 180 minutes, and the reaction and curing were performed for 180 minutes. Then, in another flask, a mixture of 0.5 parts by weight of phenol, 0.75 parts by weight of formalin, 0.5 parts by weight of water, 0.05 parts by weight of melamine, and 0.15 parts by weight of 28% aqueous ammonia was added. Allowed to react for minutes and cured. After cooling to 30 ° C. and addition of 2.5 l of water, the supernatant was removed, the precipitate was washed with water and air-dried. Next, this was dried under reduced pressure (5 mmHg) at 60 ° C. for 24 hours to obtain a magnetic carrier core material B.

A coating layer was provided on the obtained carrier core material B in the same manner as in Production Example 1, and the SF1 was 109, the number average particle size was 31 μm, the electric resistance was 3.8 × 10 ¹⁴ Ωcm, and σ ₁₀₀₀
Was 41 emu / g.

(Production Example 14 of Carrier) In Production Example 12, except that a non-reactive imidazole compound was used instead of melamine, SF1 was 110, the number average particle size was 30 μm, and the electric resistance value was 1 .1 × 10 ¹⁴ Ωc
Magnetic carrier XII having m and σ ₁₀₀₀ of 41 emu / g
I got

(Production Example 1 of Toner) Ion-exchanged water 710
The parts by weight was charged with 0.1M-Na ₃ PO ₄ aqueous solution 450 parts by weight, followed by heating to 60 ° C., using a TK-type homomixer (Tokushu Kika Kogyo) was stirred at 1300 rpm. To this, 68 parts by weight of a 1.0 M CaCl ₂ aqueous solution was gradually added to obtain an aqueous medium containing Ca ₃ (PO ₄ ) ₂ . Styrene 160 parts by weight n-butyl acrylate 34 parts by weight Copper phthalocyanine pigment 12 parts by weight Metal ditertiary butylsalicylate compound 2 parts by weight Saturated polyester 10 parts by weight (acid value 11, peak molecular weight 8500) monoester wax 20 parts by weight (Mw: 500) , Mn: 400, Mw / Mn: 1.25, melting point: 69 ° C, viscosity: 6.5 mPa · s, Vickers hardness: 1.1, SP value: 8.6)

The above formulation was heated to 60 ° C., and was uniformly dissolved and dispersed at 12,000 rpm using a TK homomixer (Tokusai Kika Kogyo). The polymerization initiator 2, 2 '
-Azobis (2,4-dimethylvaleronitrile) 10 g
Was dissolved to prepare a polymerizable monomer composition. The polymerizable monomer composition was charged into the aqueous medium,
Under _two atmospheres, the mixture was stirred at 10,000 rpm for 10 minutes with a Clare mixer (manufactured by M Technique Co., Ltd.) to granulate a polymerizable monomer composition. Thereafter, the temperature was raised at 80 ° C. while stirring the aqueous medium with a paddle stirring blade, and a polymerization reaction was carried out for 10 hours while maintaining the pH at 6.

After the completion of the polymerization reaction, the mixture was cooled, hydrochloric acid was added to dissolve calcium phosphate, and then filtered, washed with water and dried to obtain polymer particles (toner particles).

[0242] The obtained polymer particles were analyzed by a transmission electron microscope (T
EM) by the method of measuring the tomographic plane of polymerized particles. A core / shell structure in which the wax was encapsulated in an outer resin layer was confirmed.

The binder resin of the obtained polymer particles had the following physical properties (SP value: 19, Tg: 60 ° C.).

The specific surface area by the BET method was 100 m ² / g with respect to 100 parts by weight of the obtained polymer particles (toner particles).
0.7 parts by weight of hydrophobic titanium oxide, 0.7 parts by weight of hydrophobic silica having a BET specific surface area of 30 m ² / g and SF1 of 205 were externally added using a Henschel mixer.
After passing through a 30 mesh sieve, the weight average particle size is 7.2μ.
Thus, cyan toner 1 having m and SF1 of 108 was obtained.

(Production Example 2 of Toner)
A cyan toner 2 having a weight average particle size of 2.8 μm and an SF1 of 112 was obtained in the same manner except that the Ca ₃ (PO ₄ ) ₂ concentration was increased and the number of revolutions of the Clea mixer was set at 15,000 rpm.

(Production Example 3 of Toner)
A cyan toner 3 having a weight average particle size of 11 μm and an SF1 of 110 was obtained in the same manner except that the Ca ₃ (PO ₄ ) ₂ concentration was lowered and the rotation speed of the Clea mixer was set to 6000 rpm.

(Production Example 4 of Toner)
Cyan toner 4 was obtained in the same manner except that hydrophobic silica was not used.

(Production Example 5 of Toner) Polyester resin obtained by condensation of propoxylated bisphenol and fumaric acid 100 parts by weight Phthalocyanine pigment 4 parts by weight Aluminum complex of di-tert-butylsalicylic acid 4 parts by weight was sufficiently mixed with a Henschel mixer. Preliminary mixing was performed, and the mixture was melt-kneaded by a twin-screw extruder, cooled, coarsely pulverized to about 1 to 2 mm using a hammer mill, and then finely pulverized by an air jet pulverizer. Further, the obtained finely pulverized material was classified to have a weight average particle size of 5.8 μm and SF
Thus, a negatively triboelectrically charging cyan powder in which 1 was 142 was obtained.

Using the above powder, a cyan toner 5 was obtained in the same manner as in Production Example 1.

(Toner Production Examples 6 to 8) In Production Example 1, quinacridone PY was used instead of the copper phthalocyanine pigment.
93, magenta toner 6, yellow toner 7, black toner 8 in the same manner except that carbon black was used.
I got

Example 1 A two-component developer 1 was prepared by mixing 92 parts by weight of magnetic carrier I with 8 parts by weight of cyan toner 1.

Using this two-component developer 1, a commercially available digital copying machine GP55 (manufactured by Canon) as an image forming apparatus was modified so that the developing apparatus shown in FIG. 1 could be inserted, and the developing bias shown in FIG. 6 was used. The surface layer of both the heating roller and the pressure roller was 1.2 μm with PFA using PFA.
Changed to a configuration in which the roller was changed to a coated roller and the oil application mechanism was removed, and using an original document with an image area of 30%, 23 ° C / 60% (N / W), 23 ° C / 50% (N / W)
L) In each environment of 32.5 ° C./90% (H / H), a paper passing test of 10,000 sheets was performed, and the evaluation was performed based on the following evaluation method. The results are shown in Table 1. As can be seen from Table 1, good results were obtained.

(1) Image Density: The image density was measured using a Macbeth densitometer RD918 type (Macbeth Densitometer, manufactured by Macbeth) equipped with an SPI filter.
et RD918manufactured by
Macbeth Co. ) Was measured as the relative density of the image formed on plain paper.

(2) Carrier adhesion: A solid white image was formed, and a portion of the photosensitive drum between the developing section and the cleaner section was sampled by closely attaching a transparent adhesive tape to the sample, and the sample was 5 cm long.
The number of magnetic carrier particles adhering on the photosensitive drum in a size of 5 cm is counted, and the number of adhering carrier particles per 1 cm ² is calculated. A: Less than 5 pieces / cm ² B: 5 pieces to less than 10 pieces / cm ² C: 10 pieces to less than 20 pieces / cm ² D: 20 pieces or more

(3) Fog The average reflectance Dr (%) of plain paper before image formation was measured using a reflectometer (“REFLECTOME” manufactured by Tokyo Denshoku Co., Ltd.).
TER ODEL TC-6DS "). On the other hand, a solid white image was formed on plain paper, and the reflectance Ds (%) of the solid white image was measured. Fog (%)
Is calculated from the following equation: Fog (%) = Dr (%)-Ds (%) A: less than 0.4% B: 0.4 to less than 0.8% C: 0.8 to less than 1.2% D: 1.2% or more

(Comparative Example 1) The same procedure as in Example 1 was carried out except that the magnetic carrier core material A was used. As a result, although the fog was slightly deteriorated, a result having no practical problem was obtained. This is presumed to be due to the fact that the toner was slightly contaminated because the core material surface was not coated, so that the ability to impart charge to the toner was reduced.

(Comparative Example 2) The same operation as in Example 1 was carried out except that magnetic carrier II was used, and the result was H / H
Fog worsened. This is presumably because the nitrogen-containing compound was not used in the carrier core material, and the ability to provide a tribo for replacing a large amount of toner, which is a 30% original document, was reduced.

(Example 2) The same procedure as in Example 1 was carried out except that the magnetic carrier III was used, but good results were obtained although the fog after 10,000 copies was slightly deteriorated. This is presumably because the silicone resin coating was not performed, so that the resistance to toner spent was slightly reduced.

Example 3 The same procedure as in Example 1 was carried out except that the magnetic carrier IV was used, but good results were obtained although the image density difference due to the environment was slightly deteriorated. This is presumed to be due to the moisture absorbing properties of urea.

Example 4 The same operation as in Example 1 was carried out except that the magnetic carrier V was used. As a result, good results were obtained although the fog under N / L was slightly deteriorated. This is presumably because the coating strength was slightly reduced due to the absence of the aminosilane coupling agent.

(Comparative Example 3) The same procedure as in Example 1 was carried out except that the magnetic carrier VI was used. Since the carrier adhesion was poor from the beginning and the image density was low, the paper passing test was stopped. This is because the amount of binder resin is large, the total amount of magnetite and α-Fe ₂ O ₃ is only about 70%, the particle size distribution control of the particles does not work well,
It is presumed that a large amount of fine powder particles were generated and the carrier was attached.

(Comparative Example 4) The same procedure as in Example 1 was carried out except that the magnetic carrier VII was used. As a result, the fog was deteriorated and the image density was lowered. This is presumed to be due to the fact that the carrier holding capacity was reduced due to the large particle size of the carrier.

Comparative Example 5 The procedure of Example 1 was repeated, except that the magnetic carrier VIII was used. The evaluation was stopped because the carrier adhesion was poor from the beginning and fogging occurred. This is presumed to be because the carrier diameter is too small.

Example 5 The same procedure as in Example 1 was carried out except that the magnetic carrier IX was used, and good results were obtained.

(Example 6) The same procedure as in Example 1 was carried out except that the magnetic carrier X was used, and good results were obtained.

(Example 7) In Example 1, the toner 2
Was carried out in the same manner, except that was used. As a result, although the image density was lowered and fogging occurred, there was no practical problem. This is presumed to be due to the fact that the particle size of the toner was small, so that the miscibility with the carrier was reduced.

(Embodiment 8) In Embodiment 1, the toner 3
Was carried out in the same manner, except that fog was used. As a result, although the fog was deteriorated under H / H, there was no practical problem. This is presumed to be due to a decrease in the charge amount due to the large particle size of the toner.

(Example 9) In Example 1, the toner 4
Was carried out in the same manner as above except that fog was deteriorated under N / L, but it was at a level having no practical problem. This is because non-spherical external additives were not used.
It is presumed that the toner spent was slightly increased.

(Embodiment 10) In the embodiment 1, the toner 5
When fog was carried out in the same manner except that fog was used, the fog was deteriorated, but at a level having no practical problem. This is presumed to be due to non-uniform charging due to the irregular shape of the toner.

(Example 11) A developer was prepared using toners 7, 6, 1, and 8 in the same manner as in Example 1, and was placed in an image forming apparatus having the structure shown in FIG. 5, without using a cleaning unit. 1 in the order of yellow, magenta, cyan, and black
When image formation was performed on 0000 sheets, good results were obtained with little image density deterioration and no fog.

(Embodiment 12) In Embodiment 11, FIG.
A similar result was obtained except that the above device was used, and good results were obtained.

Example 13 The same procedure as in Example 1 was carried out except that the magnetic carrier particles XI were used. As a result, good results were obtained although the fog was slightly deteriorated under N / L. This is presumed to be due to the fact that the imidazole compound was insufficiently dispersed, but was exposed to the surface by durability, and the external additive silica adhered thereto, resulting in a decrease in charging ability.

(Example 14) The same procedure as in Example 1 was carried out except that the magnetic carrier particles XII were used, and good results were obtained.

(Example 15) The same procedure as in Example 13 was carried out except that magnetic carrier particles XIII were used.
Good results were obtained although the fog slightly deteriorated under L.

[0275]

[Table 1]

[0276]

According to the present invention, a high-definition color image with high image density can be obtained without being affected by temperature and humidity.

[Brief description of the drawings]

FIG. 1 is a schematic view of a developing device suitable for the present invention.

FIG. 2 is a schematic diagram of an apparatus used for measuring an electric resistance value.

FIG. 3 is a schematic view of an image forming apparatus suitably used in the present invention.

FIG. 4 is a schematic view of another image forming apparatus suitable for the present invention.

FIG. 5 is a diagram showing still another example of an image forming apparatus suitable for the present invention.

FIG. 6 is a diagram showing an alternating electric field used in the first embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Latent image carrier (photosensitive drum) 11 Developing sleeve (developer carrier) 12 Magnet roller 18 Supply toner 19 Developer 19a Toner 19b Carrier 21 Transport sleeve 22 Magnetic particles 31 Lower electrode 32 Upper electrode 33 Insulator 34 Ammeter 35 constant voltage device 37 carrier 38 guide ring d sample thickness E resistance measuring cell 60a transfer bias applying means (may be grounded) 61a photoreceptor drum 62a primary charger 63a developing device 64a transfer blade 65a toner hopper 66a replenishing roller 67a Exposure device 68 Transfer material carrier 69 Separation charger 70 Fixing device 71 Fixing roller 72 Pressure roller 73 Wep 75, 76 Heating means 78 Temperature detecting means 79 Transfer belt cleaning device 80 Driving roller 81 Belt driven roller 82 Bell Discharger 83 registration rollers 84 feed roller

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme court ゛ (Reference) G03G 9/10 352 354 (72) Inventor Yoshi ▲ Saki ▼ Kazumi 3-30-2 Shimomaruko, Ota-ku, Tokyo No. Canon term F-term (reference) 2H005 AA08 AA15 BA03 BA06 CA11 CA12 CA15 CA26 CA28 CB03 CB04 CB13 EA05 EA07

Claims (29)

[Claims] 1. A coating comprising a magnetic carrier core material containing at least a binder resin, ferromagnetic compound particles and non-magnetic inorganic compound particles, and one or more resins covering the surface of the core material. A magnetic-coated carrier, wherein the magnetic-coated carrier is spherical and has a number-average particle size of 5 to 100 μm; and a ferromagnetic compound particle and a non-magnetic inorganic compound particle contained in the magnetic carrier core material. Is 60 to 99% by weight based on the magnetic coated carrier, the binder resin contains at least a phenol resin, and the magnetic carrier core material contains a nitrogen-containing compound, or A magnetic-coated carrier, wherein a phenolic resin and a nitrogen-containing compound are combined in the magnetic carrier core material. 2. The magnetic carrier core material contains a nitrogen-containing compound on its surface, or a phenol resin and a nitrogen-containing compound are bonded on the surface of the magnetic carrier core material. The magnetic coated carrier according to claim 1, wherein 3. The magnetic coat according to claim 1, wherein the magnetic carrier core material is treated with a reactive coupling agent before the magnetic carrier core material is covered with the coating layer. Career. 4. The magnetic coated carrier according to claim 3, wherein the reactive coupling agent is a silane coupling agent. 5. The magnetic coated carrier according to claim 4, wherein the silane coupling agent has an amino group. 6. The magnetic coated carrier according to claim 4, wherein the silane coupling agent has at least a primary amino group. 7. The method according to claim 1, wherein the nitrogen-containing compound is urea, melamine,
7. A compound selected from the group consisting of isocyanates and imidazoles.
The magnetic coated carrier according to any one of the above. 8. The magnetic coated carrier according to claim 1, wherein the coating layer is made of a resin having a fluorine atom. 9. The magnetic coated carrier according to claim 1, wherein the coating layer is made of a thermosetting resin containing a silicon atom. 10. The magnetic coated carrier according to claim 1, wherein the nonmagnetic inorganic compound particles are nonmagnetic metal oxide particles. 11. The magnetic coated carrier according to claim 10, wherein the nonmagnetic metal oxide particles are nonmagnetic iron oxide particles. 12. The magnetic coated carrier according to claim 1, wherein the ferromagnetic compound particles are ferromagnetic iron oxide particles. 13. The magnetic coated carrier according to claim 1, wherein the ferromagnetic compound particles are magnetic ferrite particles containing at least magnesium and iron. 14. A two-component developer having at least a toner and a magnetic coat carrier, wherein the magnetic coat carrier comprises at least a binder resin,
A magnetic carrier core material containing ferromagnetic compound particles and non-magnetic inorganic compound particles, and 1 covering the core material surface
A coating layer having one or more kinds of resins, wherein the magnetic coated carrier has a spherical shape, a number average particle size of 5 to 100 μm, and a ferromagnetic material contained in the magnetic carrier core material. The total amount of the compound particles and the non-magnetic inorganic compound particles is 60 to 99% by weight based on the magnetic coated carrier, the binder resin contains at least a phenol resin, and the magnetic carrier core material is a nitrogen-containing compound. Or a phenol resin and a nitrogen-containing compound are bonded to the magnetic carrier core material. 15. The toner having a weight average particle diameter of 3 to 9 μm.
The two-component developer according to claim 14, wherein m is m. 16. The magnetic carrier core material contains a nitrogen-containing compound on the surface, or the phenol resin and the nitrogen-containing compound are bonded on the surface of the magnetic carrier core material. The two-component developer according to claim 14 or 15, wherein 17. The magnetic carrier core material is treated with a reactive coupling agent before coating the magnetic carrier core material with a coating layer. Two-component developer. 18. The two-component developer according to claim 17, wherein the reactive coupling agent is a silane coupling agent. 19. The two-component developer according to claim 18, wherein the silane coupling agent has an amino group. 20. The silane coupling agent according to claim 1, wherein the silane coupling agent has at least a primary amino group.
8. The two-component developer according to 8. 21. The two-component developer according to claim 14, wherein said coating layer is made of a resin having a fluorine atom. 22. The coating layer according to claim 14, wherein said coating layer is made of a thermosetting resin containing silicon atoms.
2. The two-component developer according to any one of 1. 23. The nitrogen-containing compound is a compound selected from the group consisting of urea, melamine, isocyanates and imidazoles.
23. The two-component developer according to any one of to 22. 24. The non-magnetic inorganic compound particles are non-magnetic metal oxide particles.
3. The two-component developer according to any one of 3. 25. The method according to claim 24, wherein the non-magnetic metal oxide particles are non-magnetic iron oxide particles.
Component developer. 26. The two-component developer according to claim 14, wherein said ferromagnetic compound particles are ferromagnetic iron oxide particles. 27. The magnetic recording medium according to claim 14, wherein the ferromagnetic compound particles are magnetic ferrite particles containing at least magnesium and iron.
Component developer. 28. The toner according to claim 28, wherein the shape factor SF1 is 100.
The two-component developer according to any one of claims 14 to 27, wherein 29. The toner according to claim 14, wherein the toner contains at least a non-spherical inorganic compound having a shape factor SF1 of 150 or more on the toner surface as an external additive.
8. The two-component developer according to any one of 8.