JP2872422B2 - Electrostatic image developing developer, image forming method, electrophotographic apparatus, apparatus unit, and facsimile apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developer for developing an electrostatic image and a developer for visualizing an electrostatic image in an image forming method such as electrophotography, electrostatic recording and electrostatic printing. The present invention relates to an image forming method, an electrophotographic apparatus, an apparatus unit, and a facsimile apparatus using the same.

More specifically, a charging step in which charging is performed by bringing charging means to which an external voltage is applied into contact with an electrostatic image carrier, and a latent electrostatic image formed on the electrostatic image carrier is used as a developer. For developing an electrostatic image used in an image forming method having a developing step of forming a developed image by developing the image, an image forming method using the developer for electrostatic image development, an electrophotographic apparatus, an apparatus unit, and a facsimile Related to the device.

[0003]

2. Description of the Related Art Conventionally, a corona discharger has been known as a charging means for charging an electrostatic image holder in an electrophotographic apparatus or the like. However, corona dischargers have problems such as the need to apply a high voltage and the generation of a large amount of ozone.

Therefore, recently, the use of contact charging means without using a corona discharger has been studied. Specifically, a voltage is applied to a conductive roller serving as a charging member, and the roller is brought into contact with an electrostatic image holder (photoconductor) as a member to be charged to charge the surface of the photoconductor to a predetermined potential. . If such a contact charging means is used, the voltage can be reduced as compared with a corona discharger, and the amount of generated ozone can be reduced.

For example, in Japanese Patent Publication No. Sho 50-13661, a low voltage can be applied when photosensitive paper is charged by using a roller whose core is covered with a dielectric material made of nylon or polyurethane rubber.

However, in the above prior art,
When the core metal is coated with nylon, there is no elasticity of rubber or the like, so that sufficient contact with the member to be charged cannot be maintained, resulting in poor charging. On the other hand, when the core metal is coated with polyurethane rubber, the softening agent impregnated in the rubber-based material exudes, and when the photoreceptor is used as the charged body, the charging member sticks to the photoreceptor when the photoreceptor stops at the contact portion. Or the area may cause image blurring. Also, if the softening agent in the rubber material of the charging member seeps out and adheres to the surface of the photoreceptor, the resistance of the photoreceptor decreases, causing image deletion. Adhered to the surface of the charging member, and a filming phenomenon sometimes occurred. When a large amount of toner adheres to the surface of the charging member, the surface of the charging member is insulated, and the charging ability of the charging member is lost, so that the charging of the surface of the photoreceptor becomes non-uniform, thereby affecting an image.

This is because the developer is strongly pressed against the surface of the photoreceptor by the charging member, so that the residual developer adheres to the charging member and the surface of the photoreceptor, and furthermore, scratches and scraping are likely to occur.

In the contact charging means according to the present invention, a DC voltage or a voltage obtained by superimposing an AC voltage on the DC voltage is applied to the charging member and is used. Abnormal charging and flying motion of the residual developer having a small particle size and light weight are repeated, which makes it easy for the residual developer to be electrostatically attracted and embedded on the charging member and the photoreceptor surface. This is very different from the case where non-contact charging means using a conventional corona discharger is used.

On the other hand, recently, small and inexpensive personal course copiers and laser printers have emerged. In these small machines, a photoconductor, a developing device, a cleaning device, and the like are integrated from a maintenance-free standpoint. It is desirable to use a magnetic one-component type developer because the cartridge type described above is used and the structure of the developing device can be simplified as the developer.

In such a method using a magnetic one-component developer, in order to form a visible image with good image quality, the developer must have high fluidity and uniform chargeability. It is necessary, and for that purpose, inorganic fine powder has conventionally been added to and mixed with toner powder. However, when hydrophilic inorganic fine particles are used, the developer to which they are added causes coagulation due to moisture in the air, resulting in reduced fluidity, and in extreme cases, the charging performance of the developer is reduced due to moisture absorption of the inorganic fine powder. Let me do it. Accordingly, it has been proposed to use hydrophobic fine silica powder among inorganic fine powders as disclosed in
6-5782, JP-A-48-47345,
It has been proposed in JP-A-48-47346. Specifically, for example, silica fine powder that has been hydrophobized by reacting silica fine powder with an organosilicon compound such as dimethyldichlorosilane to replace the silanol group on the surface of the silica fine powder with an organic group is used.

However, in the case of such a developer to which an inorganic fine powder is externally added, in the image forming step in which the photosensitive member is pressed against the photosensitive member using the contact charging means, the pressure member and the photosensitive member are particularly damaged. Therefore, fusion of the toner, filming, and the like are likely to occur, and in an extreme case, an image defect may occur.

It has been proposed to add polymer particles smaller than toner particles, that is, resin fine particles to a developer, as disclosed in JP-A-60-186854.

When a developer was prepared and examined in the same manner, it was found that there was no effect on the fusion of the toner on the photoreceptor, and in a device using contact charging, the contact charging device was contaminated and charge unevenness occurred.

[0014]

SUMMARY OF THE INVENTION An object of the present invention is to provide a developer for developing an electrostatic image, an image forming method, an electrophotographic apparatus, an apparatus unit and a facsimile apparatus which solve the above-mentioned conventional problems. I do.

That is, the present invention relates to a developer for developing an electrostatic image in which scratches are not or rarely generated on the surface of the electrostatic image holder, an image forming method using the developer for developing an electrostatic image, and an electronic device. An object of the present invention is to provide a photographic apparatus, an apparatus unit, and a facsimile apparatus.

Further, the present invention provides a developer for developing an electrostatic image, in which toner fusion does not occur on the surface of the electrostatic image carrier, or an image developer using the developer for developing the electrostatic image. It is an object to provide a method, an electrophotographic apparatus, an apparatus unit and a facsimile apparatus.

Further, the present invention provides an image forming method which includes a step of charging the electrostatic image holder by bringing the charging means into contact with the surface of the electrostatic image holder, and performing image defect even when a large number of copies are made using the image forming method. It is an object of the present invention to provide a developer for developing an electrostatic image, which does not or rarely occur, and an image forming method, an electrophotographic apparatus, an apparatus unit, and a facsimile apparatus using the developer for developing an electrostatic image.

[0018]

The developer for developing an electrostatic image of the present invention is a magnetic toner having at least a magnetic material and a binder resin, and has a Vickers hardness (Hv) of 3 to 50 kg / m.
m ² and is and resin fine average particle diameter of 0.03 to 1.0 .mu.m (A), and a hydrophobic inorganic fine powder (B) electrostatic image developer having, the resin fine particles ( The above object is achieved by the content of A) and the hydrophobic inorganic fine powder (B) satisfying the following condition: A <B.

According to the image forming method of the present invention, there is provided a charging step in which charging is performed by bringing a charging unit to which an external voltage is applied into contact with the surface of the electrostatic image holding member, and an electrostatic charge formed on the electrostatic image holding member. In an image forming unit having a developing step of developing a latent image with a developer to form a developed image, the developer is a magnetic toner having at least a magnetic material and a binder resin, and has a Vickers hardness (Hv) of 3 to 50 kg / h. mm ²
And a resin fine particle (A) having an average particle size of 0.03 to 1.0 μm, and a hydrophobic inorganic fine powder (B), the developer for developing an electrostatic image. The object is attained by the content of the resin fine particles (A) and the inorganic fine powder (B) in the developer satisfying the following condition A <B.

According to the present invention, there is provided an electrophotographic apparatus comprising: an electrostatic image holder; a charging unit for charging a surface of the electrostatic image holder;
A latent image forming method for forming a latent image on the surface of a charged electrostatic image carrier, developing means for holding a developer for developing the latent image to form a developed image, and In an electrophotographic apparatus having a transfer means for transferring to a transfer material, the developer held in the developing means is a magnetic toner having at least a magnetic material and a binder resin, and has a Vickers hardness (Hv) of 3 to 50 kg /. mm ² and is and resin fine average particle diameter of 0.03 to 1.0 .mu.m (a), and a hydrophobic inorganic fine powder (B) electrostatic image developer having the electrostatic charge image The above object is achieved by the content that the content of the resin fine particles (A) and the content of the hydrophobic inorganic fine powder (B) in the developer satisfy the following condition: A <B.

The apparatus unit of the present invention forms a unit by integrally supporting at least the developer means and the electrostatic image holder, and is a single unit detachable from the apparatus main body. The developer is a magnetic toner having at least a magnetic material and a binder resin, and has a Vickers hardness (Hv) of 3 to 50 kg / mm ^2.
And a resin fine particle (A) having an average particle size of 0.03 to 1.0 μm, and a hydrophobic inorganic fine powder (B), the developer for developing an electrostatic image. The object is attained by the content of the resin fine particles (A) and the hydrophobic inorganic fine powder (B) in the developer satisfying the following condition A <B.

A facsimile apparatus according to the present invention is a facsimile apparatus having an electrophotographic apparatus and a receiving means for receiving image information from a remote terminal, wherein the electrophotographic apparatus comprises an electrostatic image holder, a surface of the electrostatic image holder. , A latent image forming means for forming a latent image on the charged electrostatic image carrier, and a developer for developing the latent image to form a developed image. A developing means, and a transfer means for transferring the developed image to a transfer material, wherein the developer held by the developing means is a magnetic toner having at least a magnetic material and a binder resin, a Vickers hardness (Hv) Resin fine particles (A) having a particle size of 3 to 50 kg / mm ² and an average particle size of 0.03 to 1.0 μm,
And a hydrophobic inorganic fine powder (B), wherein the contents of the resin fine particles (A) and the hydrophobic inorganic fine particles (B) in the developer for electrostatic image development are as follows: The object is achieved by satisfying the following condition A <B.

It is considered that the developer for developing an electrostatic image of the present invention can achieve the above object for the following reasons.

The scratch on the surface of the photoreceptor is a contact charging member of the charging means in which the free inorganic fine powder in the developer and / or the magnetic material separated from the magnetic toner in the developer is in contact with the surface of the photoreceptor. To the inorganic fine powder and / or
Alternatively, it occurs when the surface of the photoconductor is rubbed by a magnetic material.

In particular, the amount of magnetic material released from the magnetic toner tends to increase in proportion to the number of copies, that is, the stirring time in the developing device.

Since the scratches on the surface of the photoreceptor may cause fusion of the toner to the photoreceptor, the inorganic fine powder released in the developer and / or the magnetic material detached from the magnetic toner is removed. This is effective in providing an image with no image loss even when a large number of copies are made.

The fine resin particles according to the present invention can pass through a cleaning blade, which is in contact with the surface of the photoreceptor, as a cleaning means because of their fine particle size, and have a certain degree of softness. . Therefore, when forming an image by charging the surface of the photoreceptor by contacting the charging member as a charging means, the resin fine particles according to the present invention is deformed between the charging member and the surface of the photoreceptor, the surface of the photoreceptor It is considered that free inorganic fine powder and / or desorbed magnetic material slipping from the cleaning blade in contact with the surface of the fine resin particles are adsorbed on the surface of the fine resin particles and further taken into the fine resin particles, thereby protecting the surface of the photoreceptor.

A part of the fine resin particles containing the free inorganic fine powder and / or the desorbed magnetic material adheres to the contact charging member within a range that does not adversely affect the charging of the photosensitive member, and most of the remaining adheres to the photosensitive member. Then, it is sent to the next process. In the developing step, undeformed (including deformed) resin particles contained in a developer that has developed the electrostatic latent image on the photoreceptor, together with free inorganic fine powder and / or detachable magnetic material The resin fine particles which have taken in the toner are consumed by being transferred together with the toner in the transfer step. Even if there are deformed resin fine particles remaining without being transferred in this transfer step, they are considered to be removed by the cleaning blade in the cleaning step because the deformed resin fine particles have a somewhat irregular shape due to the deformation.

The resin fine particles according to the present invention have a Vickers hardness in the range of 3 to 50 kg / mm ² , preferably
It is in the range of 5 to 30 kg / mm ² . If the Vickers hardness is less than 3 kg / mm ² , fine resin particles adhere to the charging member and inhibit charging of the developer. If the Vickers hardness is greater than 50 kg / mm ² , the charging member and the surface of the photoreceptor are not easily deformed, and the ability to take in the free inorganic fine powder and / or the detachable magnetic material is weakened, and the surface of the photoreceptor is damaged. In addition, it is not effective for fusing the toner to the photoconductor.

The Vickers hardness (Hv) of the resin fine particles is measured as follows.

First, about 0.3 g of resin fine particles were weighed, and a pressure of 400 (k) was applied using a tablet molding machine as shown in FIG.
g / cm ² ) for 5 minutes and a diameter of 10 to 15 m
m, resin fine particles having a thickness of 2 to 2.5 mm are molded. The Vickers hardness (Hv) of the molded resin fine particles is measured using a micro hardness tester (manufactured by Akashi Seisakusho) under the conditions of a load of 25 g and a holding time of 20 seconds.

The molded resin fine particles are allowed to stand for 24 hours in an environment at room temperature of 25 ° C. and a humidity of 60% Rh, and then measured under the same environment.

The resin fine particles according to the present invention have a primary average particle size in the range of 0.03 to 1.0 μm, preferably 0.05 to 0.8 μm. Those having an average particle size of more than 1.0 μm have a small specific surface area and are not suitable for adsorbing free inorganic fine powder and desorbing magnetic material, and are effective in preventing scratches on the photoreceptor surface and preventing toner fusion to the photoreceptor. Disappears. If the average particle size is smaller than 0.03 μm, the tribo of the developer becomes too high, and the density tends to decrease due to charge-up.

The average particle size of the resin fine particles according to the present invention can be measured by various methods. In the present invention, the measurement was performed using an electron micrograph.

That is, a photograph was taken at a magnification of 10,000 to 20,000 times using an electron microscope S-800 (manufactured by Hitachi, Ltd.), and 100 to 200 pieces were randomly extracted from the photographed resin fine particles, and a caliper and the like were extracted. Each diameter was measured using a measuring instrument, and the average was taken as the average particle diameter of the resin fine particles.

The fine resin particles according to the present invention are preferably contained in the developer in an amount of 0.01 to 1.0 part by weight, more preferably 0.03 to 0.5 part by weight, per 100 parts by weight of the toner. It is. When the amount of the fine resin particles contained in the developer is more than 1.0 part by weight based on 100 parts by weight of the toner, the image density tends to decrease. Incorporation of fine powder and / or detached inorganic fine particles is small and the effect of preventing fusion of the toner to the photoreceptor is small.

The quantitative relationship between the resin fine particles contained in the developer for developing an electrostatic charge image of the present invention and the hydrophobic inorganic fine powder described below is as follows: the resin fine particles are (A) and the hydrophobic inorganic fine powder is (B).
It is necessary to satisfy the following condition A <B. If the conditions are not satisfied, the fluidity tends to deteriorate, and fogging tends to occur.

The resin fine particles are produced by an emulsion polymerization method, a spray drying method or the like. Preferably, a glass transition point of 80 ° C. or higher obtained by copolymerizing components used for a toner binder resin such as styrene, acrylic acid, methyl methacrylate, butyl acrylate, and 2-ethylhexyl acrylate by an emulsion polymerization method and a soap-free polymerization method. Resin particles show good effects.

Further, the present invention may be such that the surface may be cross-linked with divinylbenzene or the like and the surface is treated with a metal, a metal oxide, a pigment, a dye, a surfactant or the like to adjust the specific electric resistance and the triboelectric charge. This is a preferred embodiment.

The inorganic fine powder according to the present invention needs to be hydrophobic, and preferably has a specific surface area of 70 to 300 m ² / g by nitrogen adsorption measured by the BET method, more preferably 100 to 300 m ² / g. Thicknesses in the range of 乃至 250 m ² / g give good results. Resin fine powder having a BET specific surface area smaller than 300 m ² / g has little effect on the addition to the developer, and resin fine powder having a BET specific surface area of more than 70 m ² / g tends to have a higher probability of being present as a free substance. Black spots are likely to be generated due to uneven deposition and aggregates.

The inorganic fine powder is preferably contained in the developer in an amount of 0.1 to 3.0 parts by weight, more preferably 0.3 to 2.0 parts by weight, based on 100 parts by weight of the toner. Range. If the amount of the inorganic fine particles contained in the developer is less than 0.1 part by weight with respect to 100 parts by weight of the toner, the effect of addition is not recognized and the image becomes rough. If the amount is more than 3.0 parts by weight, problems occur in development and fixing, which is not preferable.

As the hydrophobic inorganic fine powder according to the present invention, those having a triboelectric charge of -100 μc / g to -300 μc / g are preferably used. Tribo charge amount is -100μ
When the amount is less than c / g, the triboelectric charge of the developer itself is reduced, and the humidity characteristic tends to be reduced.
When the amount exceeds μc / g, the memory of the developer-carrying member is promoted, and the inorganic fine powder is easily affected by deterioration and the like, so that the durability characteristics are easily hindered.

The tribo value of the hydrophobic inorganic fine powder is measured by the following method. That is, 0.2 g of the inorganic fine powder left overnight in an environment of 23.5 ° C. and 60% RH and 200 to 3
Carrier iron powder not covered with resin having a main particle size of 00 mesh (for example, EFV200 manufactured by Nippon Iron Powder Co., Ltd.)
/ 300) 9.8 g was precisely weighed in the above environment, and
0c. c. Mix thoroughly (hold in hand and shake up and down about 50 times for about 20 seconds) in a polyethylene jar with a volume of.

Next, as shown in FIG. 3, about 0.5 g of the mixture is placed in a metal measuring container 32 having a 400-mesh screen 33 at the bottom, and a metal lid 34 is placed. At this time, the weight of the entire measurement container 32 is weighed and defined as W ₁ (g). next,
In the suction device 31 (at least a portion in contact with the measurement container 32 is an insulator), the air is sucked from the suction port 37 and the air volume control valve 36
Is adjusted to bring the pressure of the vacuum gauge 35 to 250 mmHg.
In this state, sufficient suction is performed to remove the inorganic fine powder by suction.
The potential of the electrometer 39 at this time is set to V (volt). Here, reference numeral 38 denotes a capacitor having a capacity of C (μF). Also, the weight of the whole measuring container after suction is weighed and W
₂ (g). The triboelectric charge (μc
/ G) is calculated as follows.

[0045]

[Outside 1]

Among the inorganic fine powders used in the present invention, particularly preferred are the so-called dry method or fumed silica produced by vapor phase oxidation of a silicon halide, and dry glass such as fumed silica, and water glass. Can be used, but there are few silanol groups on the surface and inside the silica fine powder,
Dry silica having no production residue such as ₂ O and SO ₃ ^2- is preferred.

In the case of fumed silica, a fine composite powder of silica and another metal oxide can be obtained by using another metal halide such as aluminum chloride or titanium chloride together with a silicon halide in the manufacturing process. And also includes them.

The average particle size of the particles is 0.0%.
It is desirable to be within the range of from 01 to 2μ, and it is particularly preferable to use silica fine powder within the range of from 0.002 to 0.2μ.

The method of hydrophobizing the inorganic fine powder can be carried out by using a method disclosed in the art. In particular, a silicon compound having an organosiloxane unit such as silicon oil or silicon varnish is used as the hydrophobizing agent. Is preferred.

The silicone oil which can be used as the hydrophobizing agent is represented by the general formula

[0051]

[Outside 2] R: an alkyl group having 1 to 3 carbon atoms R ': a silicon oil-modified group such as alkyl, halogen-modified alkyl, phenyl, and modified phenyl R ": an alkyl group or an alkoxy group having 1 to 3 carbon atoms, for example, dimethyl Examples include, but are not limited to, silicone oil, alkyl-modified silicone oil, α-methylstyrene-modified silicone oil, chlorophenyl silicone oil, and fluorine-modified silicone oil.

The silicone oil preferably has a viscosity of 50 to 1000 centistokes at a temperature of 25.degree. If it is less than 50 centistokes, it exerts a part due to the application of heat, and the charging characteristics tend to deteriorate. Also, 10
If it exceeds 00 centistokes, handling becomes difficult due to the processing operation. Known methods can be used as the method of silicon oil treatment. For example, fine silica powder and silicon oil are mixed using a mixer. Silicon oil is sprayed into the fine silica powder using a sprayer. Alternatively, after dissolving silicon oil in a solvent, fine silica powder is mixed, and the like, but not limited thereto.

As the silicon varnish for treating the silicic acid fine powder used in the present invention, known substances can be used.

For example, KR-25 manufactured by Shin-Etsu Silicone Co., Ltd.
1, KP-112 and the like, but are not limited thereto.

As the method of the silicone varnish treatment, the same known technique as the oil treatment can be used. It is preferable that 0.1 to 1.6 parts by weight of the treated silicic acid powder is added to 100 parts by weight of the toner, and it is particularly preferable that 0.3 to 1.6 parts by weight is added to 100 parts by weight of the toner. If the amount is less than 0.1 part by weight with respect to 100 parts by weight of the toner having excellent stability when added, the effect of addition is small, and if it exceeds 1.6 parts by weight, development and fixing problems occur, which is not preferable. .

The degree of hydrophobicity of the inorganic fine powder in the present invention is as follows:
The value measured by the following method is used. Of course, other measurement methods can be applied with reference to the measurement method of the present invention.

100 ml of ion-exchanged water and 0.1 g of a sample were put into a 200 ml separatory funnel of a sealed stopper type, and were rotated at 90 rpm with a shaking machine (Tabler shaker mixer T2C type).
Shake for 10 minutes. After shaking, the mixture was allowed to stand for 10 minutes. After the inorganic fine powder layer and the aqueous layer were separated, the lower aqueous layer was separated into 2 layers.
Collect 0 to 30 ml, put in a 10 mm cell, 500 n
The transmittance is measured based on a blank ion-exchanged water containing no silica fine powder at a wavelength of m, and the value of the transmittance is used as the degree of hydrophobicity of the inorganic fine powder.

In the present invention, the hydrophobic inorganic fine powder has a hydrophobicity of 60% or more (more preferably 90% or more). When the degree of hydrophobicity is less than 60%, it is difficult to obtain a high-quality image due to moisture adsorption of the inorganic fine powder under high humidity.

Examples of the binder resin of the magnetic toner according to the present invention include homopolymers of styrene such as polystyrene and polyvinyltoluene and substituted products thereof; styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene-
Vinyl naphthalene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-dimethylaminoethyl acrylate Polymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-dimethylaminoethyl methacrylate copolymer, styrene-vinyl methyl ether copolymer Polymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-maleic acid copolymer, styrene-maleic acid ester copolymer Styrene-based copolymers such as Methyl methacrylate, polybutyl methacrylate, polyvinyl acetate, polyethylene, polypropylene, polyvinyl butyral, polyacrylic acid resin, rosin, modified rosin, tempel resin, phenol resin, aliphatic or alicyclic hydrocarbon resin, aromatic petroleum resin, Paraffin wax, carnauba wax and the like can be used alone or in combination.

As a coloring material which can be further added to the magnetic toner according to the present invention, conventionally known carbon black, copper phthalocyanine, iron black and the like can be used.

As the magnetic fine particles contained in the magnetic toner according to the present invention, a substance which is magnetized when placed in a magnetic field is used, and powder of a ferromagnetic metal such as iron, cobalt, nickel or the like, magnetite, γ -Fe ₂ O _3, alloys and compounds such as ferrite can be used.

[0062] These magnetic fine particles are made of B by a nitrogen adsorption method.
The ET specific surface area is preferably 1 to 20 m ² / g, particularly 2.5 to 12 m ² / g, and the Mohs hardness is 5 to 7
Are preferred. The content of the magnetic powder is preferably 10 to 70% by weight based on the weight of the toner.

The magnetic toner according to the present invention preferably has a negative chargeability and may contain a charge control agent if necessary.
Negative charge control agents such as metal complex salts of monoazo dyes and metal complex salts of salicylic acid, alkyl salicylic acid, dialkyl salicylic acid or naphthoic acid are used.

The developer of the present invention may further contain other additives such as a fixing aid (eg, low molecular weight polyethylene) or a metal oxide such as tin oxide as a conductivity-imparting agent, as long as it does not substantially adversely affect the developer. Things may be added.

In the production of the magnetic toner according to the present invention, the constituent materials are kneaded well by a heat kneader such as a hot roll, a kneader, an extruder, and then mechanically pulverized.
A method obtained by classification, or a method in which a material is dispersed in a binder resin solution and then obtained by spray drying, or a method in which a predetermined material is mixed with a monomer to constitute a binder resin to form an emulsified suspension Each method can be applied, such as a polymerization toner production method in which the toner is obtained by polymerization after the polymerization.

Hereinafter, the contact charging step of the present invention applicable to the developer and the image forming method of the present invention will be specifically described.

FIG. 1 is a schematic configuration diagram of a contact charging device showing one specific example according to the present invention. Reference numeral 1 denotes a photosensitive drum which is a member to be charged as an electrostatic image holder, and an organic photoconductor (OPC) 1b which is a photosensitive layer is formed on an outer peripheral surface of a drum base 1a made of aluminum as a conductive base. It rotates at a predetermined speed in the direction of the arrow. In this specific example, the photosensitive drum 1 has an outer diameter of 30 mmφ. Reference numeral 2 denotes a charging roller, which is a charging member brought into contact with the photosensitive drum 1 at a predetermined pressure, provided with a conductive rubber layer 2b on a metal core 2a, and a surface layer 2c as a release coating on the peripheral surface thereof. Is provided. The conductive rubber layer is 0.5 to 10 mm
(Preferably 1 to 5 mm). The surface layer in this specific example is a release film, and the provision of the release film is preferable for matching with the developer and the image forming method according to the present invention. However, the release coating is
If the resistance is too high, the photosensitive drum 1 will not be charged. If the resistance is too low, a large voltage will be applied to the photosensitive drum 1 too much, causing damage to the drum and generation of pinholes. ^{9 to} 10 ¹⁴ Ωm is good,
At this time, the thickness of the release coating is preferably within 3.0 μm (preferably 10 to 30 μm). Further, the lower limit of the thickness of the film is considered to be about 5 μm if the film is free of peeling and burrs.

In this embodiment, the outer diameter of the charging roller 2 is 12
mm, and a conductive rubber layer 2b having a thickness of 3.5 mm
Is an ethylene-propylene-diene terpolymer (EPD)
M) A nylon resin having a thickness of 10 μm was used for the surface layer 2c. The hardness of the charging roller 2 is 54.5 ° (ASKE
RC). E is a power supply unit for applying a voltage to the charging roller 2 to apply a predetermined voltage to the core 2 a of the charging roller 2.
(Diameter 5 mm). In FIG. 1, E indicates a DC voltage, but a voltage obtained by superimposing an AC voltage on the DC voltage is preferable.

Preferred process conditions in this case are shown below. Contact pressure: 5 to 500 g / cm AC voltage: 0.5 to 5 kVpp AC frequency: 50 to 3000 Hz DC voltage: -200 to -900 V

FIG. 2 is a schematic structural view of a contact charging member showing another embodiment according to the present invention. The same members as those in the apparatus of FIG. 1 described above are denoted by the same reference numerals, and description thereof will not be repeated.

The contact charging member 2 'of this embodiment is in the form of a blade which is brought into contact with the photosensitive drum 1 in a forward direction at a predetermined pressure. The blade 2' is a metal supporting member 2 'to which a voltage is supplied. The conductive rubber 2'b is supported by a, and a surface layer 2'c serving as a releasable coating is provided at a contact portion with the photosensitive drum 1. Thickness 1 as surface layer 2'c
0 μm nylon was used. According to this specific example, the same operation and effect as those of the above-described embodiment can be obtained without any trouble such as adhesion between the blade and the photosensitive drum.

In the above-mentioned specific example, the roller-shaped or blade-shaped charging member is used. However, the present invention is not limited to this, and the present invention can be applied to other shapes.

In this specific example, the charging member is composed of a conductive rubber layer and a release film, but the invention is not limited to this. For preventing leakage to the photoconductor between the conductive rubber layer and the surface of the release film. For this purpose, it is preferable to form a high-resistance layer, for example, a hydrin rubber layer with small environmental fluctuation.

Further, instead of nylon resin, PVDF (polyvinylidene fluoride), PVDC
(Polyvinylidene chloride) may be used. As the photoconductor, amorphous silicon, selenium, ZnO or the like can be used. In particular, when amorphous silicon is used for the photoconductor, compared to the case where other materials are used, even if the softening agent of the conductive rubber layer adheres to the photoconductor even to a small extent, the image flow becomes severe, so The effect of the insulating coating is great.

The present invention is particularly effective for an image forming apparatus in which the surface of the electrostatic image carrier (photosensitive drum) is an organic compound. In other words, when the organic compound forms the surface layer, it has good adhesion to the binder resin contained in the toner, and particularly when the same material is used, a chemical bond is formed at the contact point. This is because transferability is deteriorated.

As the surface material of the electrostatic image carrier according to the present invention, silicone resin, vinylidene chloride, ethylene-
Examples include, but are not limited to, polyvinyl chloride, styrene-acrylonitrile, styrene-methyl methacrylate, styrene, polyethylene terephthalate, polycarbonate, and the like. Other monomers or copolymerization between exemplified resins, blends, and the like are also used. Can do things.

In the present invention, the electrostatic latent image holding member has a diameter of 50 m.
This is particularly effective for an image forming apparatus of m or less. That is, in the case of a small-diameter drum, even if the linear pressure is the same, the curvature is large, so that the pressure is likely to be concentrated at the contact portion.

It is considered that the same phenomenon occurs in the belt photosensitive member, and the present invention is also effective for an image forming apparatus having a radius of curvature of 25 mm or less at the transfer portion.

The developer for developing an electrostatic image of the present invention can be preferably used particularly for a heating roller fixing system. The heating roller fixing device usually includes a heating roller, a pressure roller disposed in contact with the heating roller, and a heating source. Further, a cleaning roller is disposed in contact with the heating roller as needed. In the fixing of the developer, the developer is transferred by passing the transfer material onto which the developer has been transferred between the heating roller and the pressure roller while maintaining the temperature of the heating roller in a certain range by a heating source. The developer is heat-fixed to the transfer material by directly contacting the heating roller. The material of the heating roller is preferably a fluorine-based material or a silicone-based material, and the durability of the heating roller can be remarkably improved by a synergistic effect with the developer of the present invention.

Further, the image forming method and the electrophotographic apparatus of the present invention will be described with reference to a specific example shown in FIG.

The surface of the photosensitive member 501 serving as an electrostatic image holding member is negatively charged by the above-described contact charger 502 having the voltage applying means 515, and the latent image forming means is subjected to image scanning by exposure 505 with a laser beam as a latent image forming means. A developing device 509 that forms a digital latent image and includes a developing sleeve 504 including a magnetic blade 511 and a magnet;
The latent image is reversal-developed with the negatively chargeable one-component developer 510 therein. In the developing section, a bias applying means 5 is provided between the conductive base of the photosensitive drum 501 and the developing sleeve 504.
12, an alternating bias, a pulse bias and / or a DC bias are applied. The transfer paper P is transported,
When the transfer unit P comes to the transfer unit, the transfer unit 503 charges the transfer paper P from the back surface (the surface opposite to the photosensitive drum side),
A developed image (developer image) on the surface of the photosensitive drum 501 is electrostatically transferred onto a transfer sheet P as a transfer material. The transfer paper P separated from the photosensitive drum 501 is subjected to a fixing process by a heating / pressing roller fixing device 507 to fix a transfer image on the transfer paper P.

The one-component developer remaining on the photosensitive drum 501 after the transfer step is removed by a cleaning device (cleaning means) 508 having a cleaning blade (or cleaning roller). After the cleaning, the photosensitive drum 501 is neutralized by the erase exposure 506, and the process starting from the charging process by the charger 502 is repeated.

The electrostatic image holder (photosensitive drum) 501 has a photosensitive layer and a conductive substrate as described above, and moves in the direction of the arrow. Non-magnetic cylindrical developing sleeve 50 as a developer carrier
Reference numeral 4 rotates in the developing section so as to advance in the same direction as the surface of the electrostatic image holding member. Inside the non-magnetic cylindrical sleeve 504, a multi-pole permanent magnet (magnet roll) as a magnetic field generating means is arranged so as not to rotate. The one-component magnetic developer 510 in the developing device 509 is applied on a non-magnetic cylindrical surface, and the friction between the surface of the sleeve 504 and the developer causes
The developer is given, for example, a negative triboelectric charge. Further, the thickness of the developer layer is reduced (from 30 μm to 500 μm) by disposing an iron magnetic doctor blade 511 close to the cylindrical surface (interval: 50 μm to 500 μm) and opposed to one magnetic pole position of the multipole permanent magnet. The developer layer is formed so as to be non-contact with the gap between the electrostatic image holding member 501 and the developer carrier 504 in the developing section so as to be non-contact. By adjusting the rotation speed of the developer carrier 504, the sleeve surface speed is substantially equal to or close to the speed of the electrostatic image holding surface. The opposed magnetic poles may be formed by using permanent magnets instead of iron as the magnetic doctor blade 511. In the developing section, an AC bias or a pulse bias may be applied between the developer carrier 504 and the surface of the electrostatic image holder 501 by the bias unit 512. The AC bias may be such that f is 200 to 4,000 Hz and Vpp is 500 to 3,000 V.

When the toner particles are transferred in the developing portion, the toner particles are transferred to the electrostatic image side by the electrostatic force on the surface of the electrostatic image holder and the action of an AC bias or a pulse bias.

Instead of the magnetic doctor blade 511,
The thickness of the developer layer may be regulated by pressing using an elastic blade made of an elastic material such as silicon rubber, and the developer may be applied on the developer carrying member.

The cleaning step may be performed simultaneously in the charging step, the developing step, or the transferring step.

As an electrophotographic apparatus, a plurality of components, such as the above-described electrostatic image holder, developing means, and cleaning means, are integrally connected as an apparatus unit, and this unit is attached to the apparatus body. It may be configured to be detachable. For example, a unit is formed by integrally supporting at least one of the charging unit, the developing unit, and the cleaning unit together with the electrostatic image holder, and is formed as a single unit detachable from the apparatus main body. It may be configured to be detachable by using. At this time, the above-described device unit may be provided with a charging unit and / or a developing unit.

When the electrophotographic apparatus of the present invention is used as a facsimile printer, the light image exposure 505 as a latent image forming means is an exposure for printing received data. FIG. 6 is a block diagram showing a specific example of this case.

The controller 611 controls the image reading unit 610 and the printer 619. The entire controller 611 is controlled by the CPU 617. The read data from the image reading unit is transmitted to the partner station through the transmission circuit 613. Data received from the partner station is sent to the printer 619 through the receiving circuit 612. Predetermined image data is stored in the image memory. Printer controller 6
Reference numeral 18 controls the printer 619. 614 is a telephone.

The image received from the line 615 (image information from the remote terminal connected via the line) is demodulated by the receiving circuit 612, and the CPU 617 performs a decoding process of the image information, and sequentially executes the image memory 616. Is stored in
When the image of at least one page is stored in the memory 616, the image of the page is recorded. CPU 61
Reference numeral 7 reads out one page of image information from the memory 616 and sends out the decoded one page of image information to the printer controller 618. The printer controller 618 uses C
Upon receiving the image information of one page from the PU 618, the printer 619 is controlled to record the image information of the page.

The CPU 617 receives the next page during recording by the printer 619.

[0092]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The basic configuration and features of the present invention have been described above, but the present invention will be specifically described below based on embodiments. However, this does not limit the embodiment of the present invention at all. Parts in the examples are parts by weight.

Production of Toner Particles (Production Example 1) 100 parts of styrene-n-butyl acrylate copolymer (copolymerization weight ratio 8: 2, Mw = 280,000) 100 parts of magnetic fine powder (BET value 8.2 m ²⁾ / G) 60 parts Negative charge control agent (monoazo dye-based chromium complex)
6 parts ・ Low molecular weight polypropylene (Mw = 6,000) 3 parts

The above raw materials were melt-kneaded in a twin-screw extruder heated to 140 ° C., and the cooled kneaded material was coarsely pulverized by a hammer mill, and the coarsely pulverized material was finely pulverized by a jet mill. The powder is classified by wind and the weight average particle size is 1
A magnetic particle classifying powder (toner) 1 (Tg 60 ° C.) of 2 μm was obtained.

(Production Example 2) Styrene-2-ethylhexyl acrylate-n-butyl maleate half ester copolymer (copolymerization ratio 7: 2: 1, Mw = 220,000)
00 parts ・ Magnetic fine powder (BET value 7.7 m ² / g) 100 parts ・ Negative charge control agent (salicylic acid chromium complex) 2 parts ・ Low molecular weight polypropylene (Mw = 6,000) 3 parts

A magnetic particle classifying powder (toner) 2 (Tg 55 ° C.) was obtained from the above raw materials in the same manner as in Production Example 1 (weight average particle size 6.5 μm).

Examples 1 to 4 and Comparative Examples 1 and 2 Resin fine particles and hydrophobic inorganic fine powder shown in Tables 1 and 2 below were added to the above magnetic toner and mixed with a Henschel mixer to obtain a developer. .

Next, each of the prepared developers was charged to an electrophotographic apparatus (LBP-manufactured by Canon) shown in FIG. 5 having a contact charging device and a cleaning blade made of polyurethane.
8II remodeling machine), a DC voltage (-700 V) and an AC voltage (500 Hz, 2000 Vpp) are applied to the contact charging device, and a toner image is continuously formed at a printing speed of 16 sheets (A4) / min by a reversal developing method. The test was performed in a normal temperature and normal humidity environment (25 ° C., 60% Rh) to evaluate the printout image. At the same time, charging member (roller type)
And the state of the surface of the photosensitive drum (electrostatic image holding member) was observed.

The photoreceptor had an abrasion characteristic of 2.5 × 10 ^-2 c by a taper abrasion tester on the surface of a drum substrate made of an organic material and a photoreceptor layer formed on an outer peripheral surface thereof.
m ³ was used.

As described above, the charging roller 2 has a diameter of 12 m.
m, the core metal has a diameter of 5 mm, and the conductive rubber layer 2b
Has a thickness of about 3.5 mm, the releasable coating formed of methoxymethylated nylon has a thickness of 20 μm, and is pressed against the OPC photoreceptor at a total pressure of 1.2 kg (linear pressure 55 g / cm). did.

In the image forming apparatus, the toner layer thickness on the sleeve is 130 μm, the closest gap between the sleeve and the OPC photosensitive member is 300 μm, and the DC bias (−500
V) and AC bias (1800 Hz, 1600 Vp)
An image output test was performed while applying p) to the developing sleeve.

Table 1 shows the physical properties of the resin fine particles (A), Table 2 shows the physical properties of the hydrophobic inorganic fine powder (B), and Table 3 shows the composition of the developer and the evaluation results. The charging device used was the roller type of FIG. 1 except that the blade type charging device of FIG. 2 was used in Example 4.

[0103]

[Table 1]

[0104]

[Table 2]

[0105]

[Table 3]

[0106]

According to the present invention, since the specific fine resin particles and the hydrophobic inorganic fine powder are contained in a smaller amount in the developer for developing an electrostatic image, the following effects can be obtained. Have. No or few scratches occur on the surface of the electrostatic image holder. The toner fusion does not occur or rarely occurs on the surface of the electrostatic image carrier. Image defects are not or do not occur even when a large number of images are formed using an image forming method including a step of charging the electrostatic image holder by bringing the charging unit into contact with the surface of the electrostatic image holder. Less.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view showing a specific example of a charging member according to the present invention.

FIG. 2 is a schematic explanatory view showing another specific example of the charging member according to the present invention.

FIG. 3 is an explanatory diagram showing an apparatus for measuring a triboelectric charge amount.

FIG. 4 is an explanatory diagram of an apparatus for measuring a volume specific resistance value.

FIG. 5 is a schematic explanatory view showing a specific example of the electrophotographic apparatus of the present invention.

FIG. 6 is a block diagram showing a specific example of the facsimile apparatus of the present invention.

[Explanation of symbols]

 Reference Signs List 501 electrostatic latent image holding member 502 charging member 503 transfer means 505 latent image forming means 509 developing means P transfer material

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Motoki Hisagi 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (56) References JP-A-62-15558 (JP, A) JP-A Sho 63-2075 (JP, A) JP-A-54-51844 (JP, A) JP-A-2-282268 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G03G 9/083

Claims (5)

(57) [Claims] 1. A magnetic toner having at least a magnetic material and a binder resin, having a Vickers hardness (Hv) of 3 to 50 kg.
/ Mm ² and an average particle size of 0.03 to 1.0 μm
Resin fine particles (A) and hydrophobic inorganic fine powder (B)
Wherein the contents of the resin fine particles (A) and the hydrophobic inorganic fine powder (B) in the developer for electrostatic image development satisfy the following condition: A <B A developer for developing an electrostatic image. 2. A charging step in which charging is performed by bringing charging means to which an external voltage is applied into contact with the surface of the electrostatic image holding member, and the electrostatic latent image formed on the electrostatic image holding member is changed by a developer. In an image forming method including a developing step of developing to form a developed image, the developer is a magnetic toner having at least a magnetic material and a binder resin, and a Vickers hardness (Hv).
Is 3 to 50 kg / mm ² and the average particle size is 0.0
A developer for developing an electrostatic charge image having resin fine particles (A) having a particle size of 3 to 1.0 μm and a hydrophobic inorganic fine powder (B), wherein the resin fine particles (A) in the developer for electrostatic charge image development And the content of the inorganic fine powder (B) satisfies the following condition A <B. 3. An electrostatic image holder, a charging unit for charging the surface of the electrostatic image holder, a latent image forming unit for forming a latent image on the charged surface of the electrostatic image holder, In an electrophotographic apparatus having developing means for holding a developer for developing a latent image to form a developed image, and a transfer means for transferring the developed image to a transfer material, the developing means is held in the developing means. The developer is a magnetic toner having at least a magnetic material and a binder resin, and has a Vickers hardness (Hv) of 3 to 5.
0 kg / mm ² and an average particle size of 0.03 to 1.
A developer for developing an electrostatic charge image having fine resin particles (A) having a particle diameter of 0 μm and a fine hydrophobic inorganic powder (B), wherein the fine resin particles (A) and the fine hydrophobic inorganic particles in the developer for developing an electrostatic charge image are provided. An electrophotographic apparatus, wherein the content of the fine powder (B) satisfies the following condition A <B. 4. An apparatus unit in which at least a developing means and an electrostatic image holder are integrally supported to form a unit, and which is a single unit detachable from the apparatus main body, the developer held by the developing means is A magnetic toner having at least a magnetic material and a binder resin, a Vickers hardness (Hv) of 3 to 50 kg / mm ² and an average particle size of 0.03
A fine resin particle (A) having a particle size of 1.0 to 1.0 μm, and a hydrophobic inorganic fine powder (B), wherein the fine resin particles (A) and An apparatus unit characterized in that the content of the hydrophobic inorganic fine powder (B) satisfies the following condition A <B. 5. A facsimile apparatus having an electrophotographic apparatus and a receiving means for receiving image information from a remote terminal, wherein the electrophotographic apparatus comprises: an electrostatic image holder; and a charging unit for charging a surface of the electrostatic image holder. Charging means, latent image forming means for forming a latent image on the surface of the charged electrostatic image carrier, developing means having a developer for developing the latent image to form a developed image, and It has a transfer means for transferring the developed image to a transfer material. The developer held by the transfer means is a magnetic toner having at least a magnetic material and a binder resin, and has a Vickers hardness (Hv) of 3 to 50 kg /. m
m ² and is and resin fine average particle diameter of 0.03 to 1.0 .mu.m (A), and a hydrophobic inorganic fine powder (B) electrostatic image developer having the electrostatic charge image A facsimile machine wherein the contents of the resin fine particles (A) and the hydrophobic inorganic fine powder (B) in the developing developer satisfy the following condition: A <B.