JP2001166533A - Nonmagnetic one-component development method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To sufficiently electrostatically charge toners with sufficient charges and to well maintain an image forming state by stably forming a uniform thin layer of the toners on the peripheral surface of a developing roller and surely preventing the occurrence of fusing and sticking of the toners to a regulating brade. SOLUTION: The toners which consist of toner particles containing a binder resin and coloring agents and external additives of inorganic particles of 30 to 50 nm in volume average grain size and is 18 to 60% in the coverage of the inorganic particles on the surfaces of the toner particles are used in the nonmagnetic one-component development method which supplies the toners formed as a thin layer on the peripheral surface of the developing roller by the metallic regulating blade and develops an electrostatic latent image to a toner image.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing method in an electrophotographic image forming process executed in an image forming apparatus such as a copying machine or a laser beam printer, and more particularly to a developing method using only a non-magnetic toner containing no carrier. And a non-magnetic one-component developing method using the developed developer.

[0002]

2. Description of the Related Art An image forming process using an electrophotographic method is described as follows.
A charging process for uniformly charging the surface of a photoconductor containing a photoconductive substance, an exposure process for exposing the surface of the photoconductor to form an electrostatic latent image, and converting the electrostatic latent image on the photoconductor surface into a toner image The process includes a development process of developing a visible image, a transfer process of transferring the toner image carried on the surface of the photoreceptor to the surface of the sheet, and a fixing process of fixing the toner image on the sheet by means such as heat and pressure. Among these, a two-component developing method using a developer composed of a toner and a carrier and a one-component developing method using a developer consisting only of a toner without a carrier are known as a method in a developing process. The one-component developing method is widely used because of its advantages such as easy maintenance, reduction in size and weight of the apparatus, and reduction in cost.

In image formation using the one-component developing method, a developing roller disposed in close proximity to a photoreceptor, a supply roller for supplying toner to the developing roller, and a peripheral surface of the developing roller in contact with the developing roller are provided. There is an image forming apparatus using a developing device including a regulating blade for reducing the thickness of a toner and applying a charge to the toner. In order to properly visualize the electrostatic latent image formed on the surface of the photoconductor in this developing method, it is necessary to always form a stable thin layer of toner on the developing roller. In recent years, the speed and life of image forming apparatuses have been increased, and a non-magnetic one-component developing method has been adopted for full-color image formation. Because the resin has a low softening point, the toner is more likely to fuse and adhere to the regulating blade than the black toner, and if the toner fuses or adheres to the regulating blade, a uniform thinning of the toner on the peripheral surface of the developing roller occurs. There is a problem that a layer is not formed and white streaks and the like are generated on an image, thereby deteriorating the image quality. Further, sufficient charge is not applied to the toner, causing problems such as generation of background fog on the image and scattering of the toner in the image forming apparatus.

To solve such a problem, Japanese Patent Application Laid-Open No.
Japanese Patent No. 6267 discloses a configuration in which silica particles are internally added to a non-magnetic one-component toner to increase the resin strength of the toner and to improve the negative charging ability of the toner by the strong negative charging characteristics of silica. Have been. In addition, Japanese Unexamined Patent Publication No.
Japanese Patent Application Publication No. 194864 discloses a configuration in which resin particles and silica particles are mixed in a toner. Further, Japanese Patent Application Laid-Open No. 10-23993 discloses a configuration in which a metal regulating blade is used, and two types of inorganic fine particles having different specific surface areas are attached to the surface of a non-magnetic toner. In addition, JP-A-11-161004 discloses that the contact pressure between the regulating blade and the developing roller is 50 g / cm to
There is disclosed a configuration in which the toner is regulated to 200 g / cm and the nonmagnetic one-component toner contains inorganic fine particles of 0.1 μm to 10 μm.

[0005]

However, in the constructions disclosed in JP-A-5-216267 and JP-A-6-194864, the transparency is poor because silica is internally added to the toner, so that full color printing is not possible. Cannot be used as a toner for printing. In addition, Japanese Patent Application Laid-Open
In the configuration disclosed in Japanese Patent No. 23993, there is a problem that the use of two types of inorganic fine particles causes an increase in cost, and a thin layer of toner on the peripheral surface of the developing roller is regulated by the influence of the inorganic fine particles having a large specific surface area. Therefore, there is a problem that not only a sufficient image density cannot be obtained, but also the fusion and fixation of the toner to the regulating blade cannot be eliminated. Further, Japanese Unexamined Patent Publication No.
The configuration disclosed in Japanese Patent No. 161004 has a problem that the contact pressure is too high, so that the fusion or adhesion of the toner to the regulating blade cannot be eliminated.

SUMMARY OF THE INVENTION It is an object of the present invention to stably form a uniform thin layer of toner on the peripheral surface of a developing roller for a long period of time, and to reliably prevent the toner from fusing or sticking to a regulating blade. Can and
It is an object of the present invention to provide a non-magnetic one-component developing method capable of charging a toner with a sufficient charge and maintaining a good image forming state.

[0007]

The present invention has the following arrangement as means for solving the above-mentioned problems.

(1) A non-magnetic one-component developing method in which a toner thinned on the peripheral surface of a developing roller by a metal regulating blade is supplied to the surface of a photoreceptor to visualize an electrostatic latent image into a toner image. , Toner particles containing a binder resin and a colorant, and an external additive of inorganic fine particles having a volume average particle diameter of 30 nm or more and 50 nm or less, and the coverage of the inorganic fine particles on the surface of the toner particles is 18%. It is characterized by using a toner of not less than 60% or less.

In this configuration, a toner obtained by externally adding inorganic fine particles having a volume average particle diameter of 30 nm to 50 nm at a coverage of 18% to 60% to toner particles containing a binder resin and a colorant is used. The developing process is performed in the electrophotographic image forming process.

When inorganic fine particles having a volume average particle diameter of less than 30 nm are used as an external additive of the non-magnetic one-component toner, the fluidity of the toner becomes too high, so that the frictional resistance of the toner particles on the developing roller becomes low. The required amount of toner is not supplied to the peripheral surface of the developing roller before facing the regulating blade, and the thickness of the thin toner layer on the peripheral surface of the developing roller after facing the regulating blade becomes thinner than a specified amount, and the image density is reduced. Decrease. On the other hand, as an external additive, the volume average particle size is 5
When inorganic fine particles exceeding 0 nm are used, the frictional resistance of the toner particle surface with respect to the developing roller becomes too high, so that a sufficient amount of toner is supplied to the peripheral surface of the developing roller before facing the regulating blade, and the toner is opposed to the regulating blade. The thickness of the thin toner layer on the peripheral surface of the developing roller later becomes thicker than a specified amount, causing fogging of the base of the image and scattering of the toner into the apparatus.

Therefore, by using inorganic fine particles having a volume average particle diameter of 30 nm or more and 50 nm or less as an external additive of the toner particles, the frictional resistance of the toner particle surface with respect to the developing roller becomes appropriate, and the frictional resistance before the toner is opposed to the regulating blade is improved. The required amount of toner is supplied to the peripheral surface of the developing roller, and a thin layer of the specified amount of toner is formed on the peripheral surface of the developing roller after facing the regulating blade. In this case, problems such as deterioration of image quality due to background fog and scattering of toner into the apparatus can be solved.

Further, if the coverage of the inorganic fine particles with respect to the toner particles in the non-magnetic one-component toner is set to 18% or less, the fluidity of the toner becomes insufficient, and the toner is separated from the peripheral surface of the developing roller by contact with the regulating blade. The surplus toner stays, the stress acting on the regulating blade increases, and the toner fuses and adheres to the regulating blade to cause poor charging of the toner. On the other hand, when the coverage of the external additive with respect to the toner particles is 60% or more, a large amount of the inorganic fine particles peeled off from the surface of the toner particles float in the toner, and the inorganic fine particles adhere to the regulating blade to cause poor charging of the toner. Occurs.

Therefore, by setting the coverage of the inorganic fine particles to the toner particles to 18% or more and 60% or less,
Sufficient fluidity is given to the toner, the stress acting on the regulating blade is reduced, and a thin layer of a specified amount of toner is stably formed on the peripheral surface of the developing roller for a long period of time. Further, it is possible to prevent the charge amount of the toner from being reduced due to the adhesion of the toner and the inorganic fine particles to the regulating blade.

(2) Resin fine particles in which the external additive has a volume average particle size ratio of 1/80 to 1/10 or less with respect to toner particles and a coverage of 1% to 15% on the surface of the toner particles. Characterized in that it contains an external additive.

In this configuration, resin fine particles having a volume average particle diameter ratio of 1/80 to 1/10 and a coverage of 1% to 15% on the surface of the toner particles are externally added to the toner particles. You.

By using fine resin particles as an external additive of the non-magnetic one-component toner, the frictional resistance on the surface of the toner particles can be increased, but the fine resin particles having a volume average particle diameter ratio to the toner particles of less than 1/80 can be obtained. In this case, the effect of increasing the frictional resistance on the surface of the toner particles becomes insufficient. On the other hand, when resin fine particles having a volume average particle diameter ratio of more than 1/10 to toner particles are used as an external additive, the frictional resistance of the toner particle surface to the developing roller becomes too high, and the developing roller before the regulating blade faces the regulating blade. An amount of toner more than necessary is supplied to the peripheral surface, and the thickness of the thin toner layer on the peripheral surface of the developing roller after being opposed to the regulating blade becomes thicker than a specified amount, and the charge amount of the toner becomes too high. This causes fogging of the base and scattering of the toner into the apparatus.

On the other hand, if the coverage of the resin particles with respect to the toner particles in the non-magnetic one-component toner is less than 1%, the effect of increasing the frictional resistance on the surface of the toner particles becomes insufficient.
On the other hand, the coverage of the resin particles with respect to the toner particles is 15%.
If it exceeds, the frictional resistance of the toner particle surface becomes too high.

Therefore, resin fine particles having a volume average particle diameter ratio of 1/80 to 1/10 are added to the external additive of the toner particles.
By externally adding the toner particles so that the coverage on the surface of the toner particles is 1% or more and 15% or less, the frictional resistance of the toner particle surface with respect to the developing roller becomes appropriate,
A thin layer of a specified amount of toner is formed on the peripheral surface of the developing roller after being opposed to the regulating blade, which causes problems such as deterioration of image quality due to image fogging of the base and scattering of the toner into the apparatus. Is eliminated.

(3) The resin fine particles are a thermosetting resin.

In this configuration, thermosetting resin particles are externally added to the toner particles. If a thermoplastic resin such as PMMA is contained in the external additive of the non-magnetic one-component toner, the toner is likely to be fused and fixed to the regulating blade after long-term use. Therefore, by using a thermosetting resin such as a melamine-based resin as the resin fine particles contained in the external additive in order to increase the frictional resistance of the toner particle surface with respect to the developing roller, the toner for the regulating blade can be used for a long period of time. , And a specified amount of a thin layer is stably formed on the peripheral surface of the developing roller.

(4) The inorganic fine particles are silica.

In this configuration, silica is externally added to the toner particles. If alumina or titanium oxide is used as the inorganic fine particles to be externally added to the non-magnetic one-component toner, the fluidity of the toner decreases and the thin layer formed on the peripheral surface of the developing roller becomes too thick, and the charge amount of the toner is increased. And the problem of fogging of the background of the image and scattering of the toner into the apparatus occurs. Therefore, by using silica as the inorganic fine particles, the fluidity of the toner is maintained, a thin layer of a predetermined amount of toner is formed on the peripheral surface of the developing roller, and the charge amount of the toner becomes appropriate. There is no deterioration or contamination inside the device.

(5) The toner is a color toner using a polyester resin as a binder resin.

In this configuration, the configurations (1) to (3) are applied to a color toner using a polyester resin as a binder resin. Therefore, the color toner
The operation according to the configurations of (1) to (3) occurs.

(6) The regulating blade comes into pressure contact with the peripheral surface of the developing roller with a linear pressure of 15 gf / cm or more and 50 gf / cm or less.

In this configuration, a thin layer of toner is formed on the peripheral surface of the developing roller by a regulating blade that presses against the peripheral surface of the developing roller with a linear pressure of 15 gf / cm or more and 50 gf / cm or less. If the pressing force of the regulating blade against the peripheral surface of the developing roller is too weak, the thickness of the thin layer of toner will not be uniform, and if the pressing force is too strong, the toner will adhere and adhere to the regulating blade due to long-term use. . Therefore, by regulating the pressure contact force of the regulating blade against the peripheral surface of the developing roller to a linear pressure of 15 gf / cm or more and 50 gf / cm or less, a thin layer of a specified amount of toner is stably formed on the peripheral surface of the developing roller. In addition, the toner does not fuse or adhere to the regulating blade even after long-term use.

(7) The regulating blade is characterized in that a tip portion is disposed upstream of the supporting portion in the rotation direction of the developing roller.

In this configuration, the tip of the regulating blade faces the peripheral surface of the developing roller before the supporting portion. Accordingly, the tip of the regulating blade is pressed against the entire peripheral surface of the developing roller with a uniform linear pressure, and a thin layer of a predetermined amount of toner is stably formed on the peripheral surface of the developing roller.

(8) The regulating blade is characterized in that the portion from the tip to the support is formed in a flat plate shape.

In this configuration, the regulating blade, which is formed in a flat shape from the tip to the support, abuts on the peripheral surface of the developing roller. Therefore, the regulating blade, which does not have a bent portion at which the toner tends to stay, is not formed at the front end portion, contacts the peripheral surface of the developing roller, and a thin layer of a predetermined amount of toner is uniformly formed on the peripheral surface of the developing roller.

(9) The developing roller visualizes an electrostatic latent image on the surface of the photoreceptor into a toner image with the peripheral surface in contact with the surface of the photoreceptor, and has an Asker C hardness of 50. The angle is not less than 85 ° and not more than 85 °.

In this configuration, Asker C hardness is 5
Visualization of the electrostatic latent image is performed in a state where the peripheral surface of the developing roller at 0 ° or more and 85 ° or less and the surface of the photoconductor are in contact with each other. In the contact developing method in which the peripheral surface of the developing roller and the surface of the photoconductor are in contact with each other, if the Asker C hardness of the developing roller exceeds 85 °, the contact force on the surface of the photoconductor becomes too high, and the photoconductor is rotated smoothly. And stripes appear in the image in the direction of the rotation axis of the photoconductor. On the other hand, Asker C of the developing roller
If the hardness is less than 50 °, there is a problem that deformation occurs during continuous use or when left for a long period of time. Silicon rubber, which can be considered as a material that can achieve this hardness, has a large amount of residual oil, and the surface of the photoreceptor may be affected by oil. There is a problem that the image is stained and white spots on the image occur. Therefore, Asker C
When a developing roller having a hardness of 50 ° or more and 85 ° or less is used for the contact developing method, the photosensitive member can be smoothly rotated, and urethane rubber or the like that does not stain the surface of the photosensitive member can be used. And no image degradation occurs.

[0033]

BEST MODE FOR CARRYING OUT THE INVENTION A non-magnetic one-component developing method according to an embodiment of the present invention is described below with reference to a developing apparatus to which the developing method is applied, a toner to be used in the developing method, and examples of the developing method. The description will be made in the order of the result of comparison with the comparative example.

A. Developing Apparatus FIG. 1 shows a configuration of a main part of an image forming apparatus to which a non-magnetic one-component developing method according to an embodiment of the present invention is applied. Inside the image forming apparatus, there is provided a developing device 6 facing the peripheral surface of the photosensitive drum 5 rotatably supported in the direction of arrow A. The developing device 6 includes a developing roller 1, a regulating blade 2,
The apparatus includes a supply roller 3 and a stirring roller 4, and contains a non-magnetic one-component toner (hereinafter, simply referred to as toner). The peripheral surface of the photosensitive drum 5 is
Before facing the charger 7 and an optical system device (not shown). The peripheral surface of the photoreceptor drum 5 is uniformly charged with a single-polarity charge by the charger 7 and then receives irradiation of image light from an optical system device to form an electrostatic latent image.

The developing roller 1 is made of urethane rubber, silicon rubber, NBR, EPDM or natural rubber and is formed in a cylindrical shape with an Asker C hardness of 50 ° to 85 °, and is rotatable in the direction of arrow B. Supported. The developing roller 1 bears a thin layer of toner on the peripheral surface, and contacts the portion of the peripheral surface of the photosensitive drum 5 where the electrostatic latent image is formed to convert the electrostatic latent image into a toner by a contact developing method. Visualize the image.

The regulating blade 2 is formed of a metal material such as SUS, aluminum or phosphor bronze into a flat plate shape having no bent portion at the tip end.
At a position upstream of the developing roller 1 in the rotation direction of the developing roller 1, the developing roller 1 is pressed against the peripheral surface of the developing roller 1 to form a thin layer of toner having a predetermined thickness on the peripheral surface of the developing roller 1.

The supply roller 3 is formed in a cylindrical shape using urethane sponge or the like, and rotates in the direction of arrow C to supply the toner to the peripheral surface of the developing roller 1. The stirring roller 4 is rotatably supported in the direction of arrow D, and stirs the toner stored in the developing device 6 to charge the toner with a predetermined charge.

B. Toner a. Binder Resin The binder resin of the toner used in the non-magnetic one-component developing method according to the embodiment of the present invention includes, for example, polystyrene, poly-p-chlorostyrene, poly-p-methylstyrene, and styrene-chlorostyrene. Polymer, styrene-
Propylene copolymer, styrene-butadiene copolymer,
Styrene-vinyl chloride copolymer, styrene-vinyl acetate copolymer, styrene-maleic acid copolymer, styrene
Acrylic ester copolymer (styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer,
Styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-phenyl acrylate copolymer, etc., styrene-methacrylic ester copolymer (styrene-methyl methacrylate copolymer, styrene-methacrylic) Ethyl acrylate copolymer, styrene-butyl methacrylate copolymer, styrene-octyl methacrylate copolymer, styrene-phenyl methacrylate copolymer), styrene-α-methyl methacrylate copolymer, styrene-acrylonitrile Styrene resins such as acrylic acid copolymers (homopolymers or copolymers containing styrene or styrene substituents), polyvinyl chloride, low molecular weight polyethylene, low molecular weight polypropylene, ethylene-ethyl acrylate copolymer, Pinyl butyral, ethylene-vinyl acetate A copolymer, a rosin-modified maleic resin, a phenol resin, an epoxy resin, a polyester resin, an ionomer resin, a polyurethane resin, a silicone resin, a ketone resin, a xylene resin, a polyamide resin, or the like alone or a mixture of two or more. Can be used. Incidentally, as the binder resin of the full-color toner, a polyester resin is preferable from the viewpoint of control of thermal characteristics and the like.

B. Colorant As the colorant of the toner, various colors can be used for each color of yellow, magenta, cyan and black.

As the colorant of the yellow toner, for example, C.I. I. Pigment Yellow 1, C.I. I. Pigment Yellow 5,
C. I. Pigment Yellow 12, C.I. I. Pigment Yellow 15 or C.I. I. Pigment Yellow 17
Azo pigments or inorganic pigments such as yellow iron oxide or loess can be used. Also, as the dye,
For example, C.I. I. Nitro dyes such as Agit Yellow 1 or C.I. I. Solvent Yellow 2, C.I. I. Solvent Yellow 6, C.I. I. Solvent Yellow 1
4, C.I. I. Solvent Yellow 15, C.I. I. Solvent Yellow 19 or C.I. I. Oil-soluble dyes such as Solvent Yellow 21 can be used. In particular, C.I.
I. Benzidine pigments such as CI Pigment Yellow 17 are preferred in terms of color.

Examples of the colorant for the magenta toner include C.I. I. Pigment Red 49, C.I. I. Pigment Red 57, C.I. I. Pigment Red 81, C.I.
I. Pigment Red 122, C.I. I. Solvent Red 19, C.I. I. Solvent Red 49, C.I. I. Solvent Red 52, C.I. I. Basic Red 10 or C.I. I. Disperse Red 15 or the like can be used. I. A quinacridone pigment such as CI Pigment Red 122 is preferred from the viewpoint of color.

As the colorant for the cyan toner, C.I. I.
Pigment Blue 15, C.I. I. Pigment Blue 1
6, C.I. I. Solvent Blue 55, C.I. I. Solvent Blue 70, C.I. I. Direct Blue 25 or C.I.
I. Direct Blue 86 or the like can be used. I. Pigment blue 15 and other copper phthalocyanine pigments are preferred in terms of color.

As a colorant for the black toner, carbon black is preferable.

The amount of the colorant to be added is 1 to 30 parts by weight, preferably 2 to 20 parts by weight, based on 100 parts by weight of the binder resin.

C. Charge control agent For the toner used in the non-magnetic one-component developing method according to the embodiment of the present invention, for the purpose of controlling the frictional charging property of the toner,
A charge control agent is included. This charge control agent has a positive charge control and a negative charge control depending on the charging characteristics of the toner. As the charge control agent for controlling the positive charge, use of an organic compound having a basic nitrogen atom, for example, a basic dye, a quaternary ammonium salt, an aminopyrine, a pyrimidine compound, a polynuclear polyamino compound, an aminosilane, or a nigrosine base Can be. As the charge control agent for negative charging, an oil-soluble dye such as oil black or spiron black, a metal-containing azo dye, a metal salt of naphthenic acid, a metal salt of alkyl salicylic acid, a fatty acid soap or a resin acid soap can be used. .

The charge control agent is added in an amount of 0.1 to 10 parts by weight, preferably 0.5 to 10 parts by weight, per 100 parts by weight of the binder resin.
8 parts by weight. The color toner is preferably a colorless quaternary ammonium salt or a metal salt of alkyl salicylic acid, but is not essential.

D. Inorganic Fine Particles and Resin Fine Particles In the toner used in the non-magnetic one-component developing method according to the embodiment of the present invention, inorganic fine particles and resin fine particles are externally added. As the inorganic fine particles, for example, fatty acid metal salts, zinc stearate, calcium stearate, lead stearate, zinc oxide powder, aluminum oxide powder, titanium oxide powder, fine silica powder, and the like can be used. In addition, a melamine resin is used as the resin fine particles.

E. Manufacturing Method The toner particles used in the non-magnetic one-component developing method according to the embodiment of the present invention have an average particle diameter of 3 μm to 15 μm.
Use In particular, a small particle size toner having an average particle size of 9 μm or less is used for obtaining a high quality image, and a small particle size toner having a size of 5 μm to 8 μm is preferable for improving image quality.

For the toner, a mixture obtained by uniformly premixing the above-mentioned additives such as the binder resin and the colorant by a dry blender, a super mixer, a ball mill or the like is used, for example, by a hand mixer, a roll, or a uniaxial mixer. Alternatively, the mixture is uniformly melt-kneaded using a kneading apparatus such as a biaxial extrusion kneader, and then the obtained kneaded product is cooled and pulverized, and further classified as necessary. The obtained toner is commercialized by adding the above-mentioned inorganic fine particles and resin fine particles as an external additive, and then removing aggregates and foreign substances with a sieve or the like.

C. Examples and Comparative Examples a. Toner Production Method 100 parts by weight of a polyester, 5.0 parts by weight of a colorant (copper phthalocyanine), and 2.0 parts by weight of a charge control agent (zinc compound of salicylic acid) are uniformly mixed by a super mixer, and then mixed by a twin screw extruder. The mixture was heated, melted, kneaded and cooled. The obtained kneaded material was coarsely pulverized by a cutting mill, then finely pulverized by an ultrasonic jet mill, and fine particles having a volume-converted particle size of 5 μm or less were removed by a classifier to obtain a toner. The particle size of the toner is distributed in the range of 5 μm to 16 μm in terms of volume, and the volume average particle size of the toner is 8.0 μm.
m.

B. Image Forming Apparatus In the image forming apparatus having the configuration shown in FIG. 1, the applied voltage to the developing roller 1 is -300 V, and the applied voltage to the regulating blade 2 and the supply roller 3 is -400 V. The peripheral speed ratio of 0.9,
The peripheral speed ratio between the developing roller 1 and the photosensitive drum 5 was 1.5, and the process speed was 90 mm / sec.

C. Measurement of the amount of toner attached to the developing roller and the amount of charge The counter charge when the toner attached to the peripheral surface of the developing roller 1 is suctioned by a suction method is measured, and the amount of toner charged and the weight of the sucked toner are measured to determine the specific charge. I asked. In addition, a transparent tape (Mending Tape manufactured by Sumitomo 3M) was attached to the suction mark on the peripheral surface of the developing roller 1 and then attached again on white paper to measure the suction area, and the amount of toner adhered per unit area was determined. Was.

D. Actual Photographic Test The developing device of the AR-5030 manufactured by Sharp was remodeled for non-magnetic one-component development, and a continuous actual photorealistic test of 30,000 sheets was conducted in a normal temperature and normal humidity environment.

E. Image Density Measurement The image density on paper was measured using an X-rite 938 densitometer manufactured by X-rite.

F. PC fog measurement A transparent tape (Mending Tape manufactured by Sumitomo 3M) was attached to a non-image portion on the peripheral surface of the photosensitive pair drum 5, and then attached again to a blank sheet of paper, and X-rite 93 manufactured by X-rite was used.
8 The density was measured using a densitometer, and the difference between this density and the measured density on white paper when the transparent tape was directly applied was defined as the PC fog value.

G. Confirmation of fused material on regulating blade After the developing roller 1 was removed and the toner on the regulating blade 2 was blown off by a blower, the state of the surface of the regulating blade 2 was confirmed by an optical microscope. Also, a transparent tape (Mending tape manufactured by Sumitomo 3M) is applied to the developing roller 1.
And then pasted again on white paper, and visually checked for white streaks.

H. External Addition Prescription and Development Conditions The above-described actual test was performed on the toner to which the external additive consisting of only inorganic fine particles was added, using the combination shown in FIG. In addition, the above-described actual test was performed on the toner in which the external additive including the resin fine particles was added to the inorganic fine particles, using the combination shown in FIG.

I. Actual Photographic Test Results The toner adhesion amount and specific charge on the peripheral surface of the developing roller 1 at the initial stage and after the actual photorealistic test, image density, and P
C fog was measured, and the presence or absence of toner fusion on the regulating blade 2 was confirmed. The results are shown in FIGS. 4 and 5 for the combination of FIG. 2, and shown in FIGS. 6 and 7 for the combination of FIG.

First, as is clear from the results of the test conducted on the combination of FIG. 2 shown in FIGS. 4 and 5, in Comparative Example 1, the effect of improving the fluidity was great because the particle size of the inorganic fine particles was small. Sufficient toner was not supplied to the peripheral surface of the developing roller 1 on the upstream side of the regulating blade 2 in the rotation direction 1, and the amount of toner adhered to the peripheral surface of the developing roller 1 was insufficient from the beginning. As a result, 1000
At the time of continuous actual copying of the sheets, fusion of the toner on the regulating unit third 2 occurred.

In Comparative Example 2, since the particle diameter of the inorganic fine particles was large, the frictional resistance of the surface of the toner particles with respect to the developing roller 1 was large, so that the circumference of the developing roller 1 was located upstream of the regulating blade 2 in the rotation direction of the developing roller 1. More toner than necessary was supplied to the surface, and the amount of toner attached to the peripheral surface of the developing roller 1 increased. As a result, the image density and PC fog increased.

In Comparative Examples 3 and 4, the flowability of the toner was reduced during the continuous image formation due to the small amount of the inorganic fine particles added, and the addition amount of the inorganic fine particles was too large. Since the amount of suspended inorganic fine particles detached from the toner particles in the toner increased, fusion of the toner and the inorganic fine particles to the regulating blade 2 occurred.

In Comparative Example 5, the charge amount of the toner is slightly lower and the PC fog value is higher from the beginning. In Comparative Example 6, the pressing force of the regulating blade 2 against the developing roller 1 was too high, and the amount of toner adhered to the peripheral surface of the developing roller 1 was small from the initial stage. Occurred.

In Comparative Example 7, stripes were formed on the image. This is because the hardness of the developing roller 1 was too high, the photosensitive drum 5 did not rotate smoothly, and banding occurred.

In Comparative Examples 8 and 9, titanium oxide was used as the inorganic fine particles, but the charge amount of the toner was slightly low and the PC fog value was slightly high from the beginning. In addition, the PC fog value after 3000 continuous actual shootings increased to an unacceptable level. Therefore, it is preferable to use silica as the inorganic fine particles.

In contrast, Examples 1 to 8 of the present invention
In the above, inorganic fine particles having a volume average particle diameter of 30 nm or more and 50 nm or less and a coverage of 18 to 60% on the surface of the toner particles were added to the toner as an external additive. The pressing force of the regulating blade 2 against the peripheral surface of the developing roller 1 is set to a linear pressure of 15 gf / cm to 50 gf / cm, and the hardness of the developing roller 1 is set to an Asker C hardness of 50 ° to 8 °.
5 ° or less. As a result, a thin layer of a specified amount of toner can be formed on the peripheral surface of the developing roller 1, and no fusion of toner or the like occurs on the regulating blade 2, and stable image quality can be stably provided for a long period of time. An image was obtained.

Next, as is apparent from the results of the test conducted on the combination of FIG. 3 shown in FIGS. 6 and 7, in Comparative Example 11, the effect of improving the fluidity of the toner was small, and the effect on the peripheral surface of the developing roller 1 was small. The amount of adhered toner has increased. As a result, the image density and the PC fog value increased. On the other hand, in Comparative Example 12, the effect of improving the fluidity was too large, and the charge amount of the toner by the regulating blade 2 was low,
PC fog increased slightly.

In Comparative Examples 13 and 14, the flowability of the toner was reduced during the continuous operation due to the small amount of the inorganic fine particles added. Since the amount of the suspended inorganic fine particles detached from the toner particles increased, the toner and the inorganic fine particles were fused to the regulating blade 2.

In Comparative Examples 15 to 18, the effect of increasing the frictional resistance of the surface of the toner particles with respect to the developing roller 1 was reduced when the particle size of the resin particles was small and when the coverage of the resin particles with respect to the toner particles was low. However, the charge amount of the toner was low, and the PC fog value was slightly increased. Further, when the particle size of the resin fine particles is large and when the covering ratio of the resin fine particles to the toner particles is high, the frictional resistance of the toner particle surface to the developing roller 1 becomes too high, and the toner on the peripheral surface of the developing roller 1 Fluctuates in the amount of toner particles, and the image density becomes too high.

In Comparative Examples 19 and 20, if the pressing force of the regulating blade 2 against the developing roller 1 was too low, the charge amount of the toner was slightly lower from the initial stage, and the PC fog value was higher.
The pressing force of the regulating blade 2 against the developing roller 1 was too high, and the amount of toner adhered to the peripheral surface of the developing roller 1 was small from the initial stage, and the toner was fused to the regulating blade 2 during continuous actual printing of 3000 sheets.

In Comparative Example 21, the hardness of the developing roller 1 was too high, the photosensitive drum 5 did not rotate smoothly, and banding caused banding in the image.

In Comparative Example 22, the acrylic fine particles were used as the resin fine particles, but the toner adhered to the regulating blade 2 at the time of continuous actual copying of 3000 sheets. This is considered to be caused by the acrylic fine particles having thermoplasticity and being caused by frictional heat between the regulating blade 2 and the toner.

In Comparative Example 23, titanium oxide was used as the inorganic fine particles, but the charge amount of the toner was slightly low from the initial stage.
The PC fog value was slightly higher. This is probably because the resistance value of titanium oxide is relatively low.

In contrast, Embodiments 11 to 11 of the present invention
In No. 30, inorganic fine particles having a volume average particle diameter of 30 nm or more and 50 nm or less and a coverage of toner particles on the surface of 18% or more and 60% or less, and a volume average particle diameter ratio to the toner particles of 1/80 or more and 1/10 or less. An external additive consisting of fine resin particles having a coverage of 1% to 15% on the surface of the toner particles was added to the toner. As a result, a thin layer of a specified amount of toner can be formed on the peripheral surface of the developing roller 1, and no fusion of toner or the like occurs on the regulating blade 2, and stable image quality can be stably provided for a long period of time. An image was obtained. Further, by including the resin fine particles in the external additive, the charge amount of the toner increases, and the charge control agent added to the toner can be reduced.

[0074]

According to the present invention, the following effects can be obtained.

(1) By using inorganic fine particles having a volume average particle diameter of 30 nm or more and 50 nm or less as an external additive of the toner particles, the friction resistance of the toner particle surface with respect to the developing roller can be made appropriate, and the regulating blade can be used. The required amount of toner is supplied to the peripheral surface of the developing roller before facing the regulating blade, and a thin layer of the specified amount of toner can be formed on the peripheral surface of the developing roller after facing the regulating blade, thereby lowering the image density. And problems such as deterioration of image quality due to image fogging and background fog, and scattering of toner into the apparatus can be solved. Further, the coverage of the inorganic fine particles with respect to the toner particles is 18% or more and 60% or more.
% Or less, sufficient fluidity can be given to the toner, the stress acting on the regulating blade is reduced, and a thin layer of the specified amount of toner is stably formed on the peripheral surface of the developing roller for a long period of time. It is possible to prevent the toner and inorganic fine particles from adhering to the regulating blade, thereby preventing a decrease in the charge amount of the toner.

(2) Resin fine particles having a volume average particle diameter ratio of 1/80 or more and 1/10 or less are added to the external additive of the toner particles so that the coverage on the surface of the toner particles is 1% or more and 15% or less. By externally adding the toner particles, the frictional resistance of the surface of the toner particles with respect to the developing roller can be made appropriate, and a thin layer of a predetermined amount of toner can be formed on the peripheral surface of the developing roller after facing the regulating blade. In this case, problems such as deterioration of image quality due to background fog and scattering of toner into the apparatus can be solved.

(3) By externally adding the thermosetting resin particles to the toner particles, it is possible to reliably prevent the toner from being fused and fixed to the regulating blade even after long-term use. A prescribed amount of a thin layer can be stably formed on the peripheral surface.

(4) By externally adding silica to the toner particles, the fluidity of the toner can be maintained, a thin layer of a specified amount of toner can be formed on the peripheral surface of the developing roller, and the charge amount of the toner can be adjusted appropriately. In addition, it is possible to reliably prevent deterioration of image quality and contamination in the apparatus.

(5) The effects of the constitutions (1) to (3) also occur for a color toner using a polyester resin as a binder resin.

(6) By regulating the pressing force of the regulating blade against the peripheral surface of the developing roller to a linear pressure of 15 gf / cm or more and 50 gf / cm or less, a thin layer of a specified amount of toner can be stably formed on the peripheral surface of the developing roller. The toner can be reliably prevented from being fused and fixed to the regulating blade even after long-term use.

(7) The leading end of the regulating blade is opposed to the peripheral surface of the developing roller before the supporting portion, so that the leading end of the regulating blade is pressed against the entire peripheral surface of the developing roller with a uniform linear pressure. Thus, a thin layer of a predetermined amount of toner can be stably formed on the peripheral surface of the developing roller.

(8) A regulating blade having a flat shape from the tip to the support is brought into contact with the peripheral surface of the developing roller, so that the regulating blade without a bent portion at the tip contacts the peripheral surface of the developing roller. As a result, a thin layer of a predetermined amount of toner can be uniformly formed on the peripheral surface of the developing roller.

(9) The electrostatic latent image is visualized in a state where the peripheral surface of the developing roller having Asker C hardness of 50 ° to 85 ° is in contact with the surface of the photoreceptor, thereby smoothing the photoreceptor. And a material such as urethane rubber that does not stain the surface of the photoreceptor can be used, so that image deterioration does not occur.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a main part of an image forming apparatus to which a non-magnetic one-component developing method according to an embodiment of the present invention is applied.

FIG. 2 is a view showing a combination of toners to which an external additive consisting of only inorganic fine particles is added, which is used in a real-world test of a non-magnetic one-component developing method according to an embodiment of the present invention.

FIG. 3 is a diagram showing a combination of a toner to which an external additive composed of inorganic fine particles and resin fine particles is added, which is used in a real test of the non-magnetic one-component developing method according to the embodiment of the present invention.

FIG. 4 is a diagram showing the actual shooting test result of the embodiment of FIG. 2;

FIG. 5 is a diagram showing the actual shooting test result of the comparative example of FIG. 2;

FIG. 6 is a diagram showing the actual shooting test result of the embodiment of FIG. 3;

FIG. 7 is a diagram showing the actual shooting test result of the comparative example of FIG. 3;

[Explanation of symbols]

 1-Developing roller 2-Regulator blade 3-Supply roller 4-Agitating roller 5-Photoconductor drum 6-Developing device

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G03G 15/08 504 G03G 9/08 374 (72) Inventor Tetsu Ogawa 22-22 Nagaikecho, Abeno-ku, Osaka-shi, Osaka No. Sharp Corporation F term (reference) 2H005 AA01 AA08 AA21 CA08 CA15 CA17 CB13 EA05 EA07 EA10 FA07 2H030 AD01 BB33 2H077 AD02 AD06 AD13 AD17 AD23 BA10 DB14 DB25 EA14 EA24 FA22 GA13

Claims (9)

[Claims] 1. A non-magnetic one-component developing method for supplying a toner thinned on the peripheral surface of a developing roller by a metal regulating blade to a photosensitive member surface to visualize an electrostatic latent image into a toner image. A toner particle containing a binder resin and a colorant, and an external additive of inorganic fine particles having a volume average particle diameter of 30 nm or more and 50 nm or less, wherein the coverage of the inorganic fine particles on the surface of the toner particles is 18% or more. A non-magnetic one-component developing method characterized by using a toner of 60% or less. 2. The method according to claim 1, wherein the toner has a volume average particle diameter ratio of 1/80 to 1/10 or less with respect to the toner particles, and a coating rate of 1% to 15% on the surface of the toner particles. 2. The non-magnetic one-component developing method according to claim 1, further comprising an agent. 3. A non-magnetic one-component developing method according to claim 2, wherein said resin fine particles are a thermosetting resin. 4. The non-magnetic one-component developing method according to claim 1, wherein said inorganic fine particles are silica. 5. The non-magnetic one-component developing method according to claim 1, wherein the toner is a color toner using a polyester resin as a binder resin. 6. The non-magnetic monocomponent according to claim 1, wherein said regulating blade presses against a peripheral surface of the developing roller with a linear pressure of 15 gf / cm or more and 50 gf / cm or less. Development method. 7. The non-magnetic one-component developing method according to claim 1, wherein the regulating blade has a tip portion located upstream of the supporting portion in the rotation direction of the developing roller. 8. The non-magnetic one-component developing method according to claim 7, wherein said regulating blade is formed in a flat plate shape from a tip portion to a support portion. 9. A developing roller for developing an electrostatic latent image on a surface of a photoreceptor into a toner image in a state in which a peripheral surface thereof is in contact with a surface of the photoreceptor, and having an Asker C hardness of 50 ° More than 8
The non-magnetic one-component developing method according to claim 1, wherein the angle is 5 ° or less.