JPH06202460A - Nonmagnetic one-component developing method - Google Patents

Abstract

PURPOSE:To provide a nonmagnetic one-component developing method capable of obtaining excellent developing properties without melt-sticking to a layer regulating member, fogging and scattering, in contact of a nonmagnetic one- component developer with the layer regulating member. CONSTITUTION:In the noncontact type nonmagnetic one-component developing method, nonmagnetic one-component developer 3 is supplied to a developing roller 5, to form the thin layer of the nonmagnetic one-component developer 3 on the surface of the developing roller 5 by the layer regulating member 4 and simultaneously, impart a charge, and soared up by a difference in a potential between a photosensitive drum 1 and the developing roller 5, to attain development in the non-contact state with the photosensitive drum 1 holding an electrostatic latent image and then, a transfer is performed on a transfer material. In the nonmagnetic one-component developer 3, a fine grain incorporating at least a kind selected out of cerium oxide, silicon carbide and a magnetic grain is stuck to the surface of nonmagnetic toner obtained in a suspension polymerizing method.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-contact type non-magnetic one-component developing method for developing an electrostatic latent image using a non-magnetic toner.

[0002]

2. Description of the Related Art Generally, in electrophotography, an electric latent image is formed on a photosensitive drum, the latent image is then developed with toner, and the toner image is transferred to a transfer material such as paper as required. After that, it is fixed by means of heating, pressurizing or the like to obtain a copy. Developers used in such an electrophotographic method include a two-component developer including a toner and a carrier, and a one-component developer having the functions of the toner and the carrier at the same time. The one-component developer is further classified into a magnetic one-component developer and a non-magnetic one-component developer. The two-component developer has excellent electrophotographic characteristics such as transferability, fixability, and environmental resistance, but requires a toner concentration sensor to control the mixing ratio of toner and carrier, and the life of the developer is short. However, there is a problem that the stirring mechanism of the developer becomes complicated. On the other hand, the magnetic one-component developer does not require the toner concentration sensor described above, and the developing device can be easily miniaturized. However, since it contains magnetic particles, it has a problem of poor fixability. From such a background, a method using a non-magnetic toner as a one-component developer has been proposed and put into practical use in recent years in order to achieve both compactness and simplification of the apparatus and fixing characteristics.

The one-component developing method using non-magnetic toner includes a contact-type non-magnetic one-component developing method in which a developing roller carrying a developer is brought into contact with a photosensitive drum having an electrostatic latent image for development. There is a non-contact type non-magnetic one-component developing method in which a non-magnetic toner on the developing roller is caused to fly by developing by providing a constant gap between the roller and the photosensitive drum. In the non-contact type non-magnetic one-component developing method, a thin layer of the developer has to be uniformly formed on the developing roller, so that the gap between the developer and the layer regulating member is designed to be very narrow. As a result, in the conventional non-magnetic one-component developing method, a large mechanical load is applied to the developer, and the developer is fused to the layer regulating member due to frictional heat generated by the contact and sliding. Was there. When the developer is fused to the layer regulating member, the triboelectric chargeability of the developer is impaired, and the developer becomes difficult to be charged, and as a result, the phenomenon that the developer adheres to the non-image area, so-called fog or the developer from the developer There was a problem of so-called splashing.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional circumstances. Therefore, an object of the present invention is to provide a non-magnetic one-component developer which does not fuse to the layer-regulating member when the non-magnetic one-component developer is in contact with the layer-regulating member and can obtain good developability without fogging or scattering. It is to provide a developing method.

[0005]

Means for Solving the Problems As a result of intensive investigations by the present inventors, a spherical toner by a suspension polymerization method was used as a non-magnetic one-component developer, and cerium oxide, silicon carbide or It has been found that by mixing and adhering fine particles containing magnetic particles, it is possible to provide a non-magnetic one-component developing method having good developability without toner fusion to the layer regulating member, which is the above object, and complete the present invention. Came to. That is, according to the present invention, a non-magnetic one-component developer is supplied to a developing roller, a thin layer of the non-magnetic one-component developer is formed on the surface of the developing roller by a layer regulating member, and an electric charge is given to the developing roller and the developing drum. It is a non-contact type non-magnetic one-component developing method in which the non-magnetic one-component developing agent is caused to fly by a potential difference from a roller to develop in a non-contact manner on a photosensitive drum holding an electrostatic latent image, and then transferred to a transfer material. hand,
The non-magnetic one-component developer is a non-magnetic toner obtained by a suspension polymerization method, on which fine particles containing at least one selected from cerium oxide, silicon carbide and magnetic particles are attached. And a non-magnetic one-component developing method.

The present invention will be described in detail below. Figure 1
FIG. 1 is a schematic configuration diagram of a developing device used in the non-contact type non-magnetic one-component developing method of the present invention. In the figure, 1 is a photosensitive drum, 2
Is a hopper, 3 is a non-magnetic one-component developer, 4 is a layer regulating member, 5 is a developing roller using an aluminum sleeve carrying a non-magnetic one-component developer, and 6 is a non-magnetic one-component developer leakage prevention member. , 7 are stirrers. In this developing device, an electrostatic latent image is formed on the photosensitive drum 1 by a known electrophotographic method. A non-magnetic one-component developer 3 is accommodated in the hopper 2, and the non-magnetic one-component developer 3 is carried by the layer regulating member 4 on the developing roller 5 so as to have a constant layer thickness, and the layer is formed. Electric charges are applied by friction with the restriction member 4. The developing roller 5 is installed via the photoconductor drum 1 with a gap of 120 μm to 300 μm. A DC or AC voltage bias is applied to the developing roller. The non-magnetic one-component developer carried on the developing roller 5 is conveyed by the rotation of the developing roller 5, and is fly to the surface of the photosensitive drum 1 by the potential difference between the photosensitive drum 1 having an electrostatic latent image and the developing roller 5. Then, the electrostatic latent image is visualized without contact.

Next, the non-magnetic toner which constitutes the non-magnetic one-component developer of the present invention will be described in detail. The non-magnetic toner is colored particles obtained by adding a polymerization initiator to a dispersion liquid in which a colorant is dispersed in a polymerizable monomer, and then suspension-polymerizing the polymerizable monomer in an aqueous medium. Examples of the polymerizable monomer used in the present invention include the following compounds. Styrene, o-methylstyrene, m-methylstyrene, p-
Methylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, 3,4-dichlorostyrene, p-ethylstyrene, 2,4-dimethylstyrene, pn-butylstyrene, p-tert-butyl. Styrene and its derivatives such as styrene, pn-hexylstyrene, pn-octylstyrene, pn-nonylstyrene and pn-decylstyrene; ethylene unsaturated monoolefins such as ethylene, propylene, butylene and isobutylene. Kinds; Vinyl halides such as vinyl chloride, vinylidene chloride, vinyl bromide, vinyl fluoride; Organic acid vinyl esters such as vinyl acetate, vinyl propionate, vinyl benzoate; Methacrylic acid, methyl methacrylate, ethyl methacrylate , Propyl methacrylate, n-butyl methacrylate, Acrylic acid n- octyl, dodecyl methacrylate, 2-ethylhexyl methacrylate,
Methacrylic acid and its derivatives such as stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate and diethylaminoethyl methacrylate; acrylic acid, methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate. , N-octyl acrylate, dodecyl acrylate,
Acrylic acid and its derivatives such as 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate; vinyl ethers such as vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether; vinyl methyl ketone, vinyl hexyl ketone , Vinyl isopropenyl ketone and other vinyl ketones; N-vinyl pyrrole, N-vinyl carbazole, N-vinyl indole, N-vinyl pyrrolidone and other N-vinyl compounds; vinyl naphthalene compounds; acrylonitrile, methacrylonitrile, acrylamide and the like. These monomers may be used alone or in combination of two or more. It is preferable to use styrene or a styrene derivative alone or in combination with other monomers in order to improve the environmental characteristics and durability of the non-magnetic toner.

As the colorant, for example, black colorants such as carbon black, acetylene black, lamp black, channel black, aniline black, and the like,
Examples of chromatic colors include Farnal Blue, Permanent Blue, Nigrosine Blue, Phthalocyanine Cyan Color Pigment, Rose Bengal, Xanthene Magenta Color Dye, Quinacridone Magenta Color Pigment, Monoazo Red Pigment, and Disazo Yellow Pigment. However, the present invention is not limited to these.

The non-magnetic toner constituting the present invention is manufactured through the following steps. First, a dispersion liquid containing a polymerizable monomer and a colorant is prepared. At this time, it is preferable to add an organic peroxide to the dispersion liquid in order to uniformly disperse the colorant in the polymerizable monomer. In particular, an organic peroxide having an alkyl group having 13 or more carbon atoms in the longest carbon atom chain is preferable. Examples of such organic peroxides include the following compounds. Stearyl peroxide, palmityl peroxide, behenyl peroxide, myristyl peroxide, stearyl peroxyphenoxyacetate, myristyl peroxyphenoxyacetate, α-
Cumyl peroxystearate, α-cumyl peroxy myristyrate, t-butyl peroxy stearate,
t-butyl peroxymyristyrate, α-cumylperoxybehenate, α-cumylperoxyacetylate,
t-butyl peroxybehenate, t-butyl peroxyacetylate and the like. The amount of the organic peroxide used is 0.01 to 10 parts by weight, preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the polymerizable monomer.

As a method of dispersing the colorant in the polymerizable monomer, a method of heating the dispersion while stirring is used. In that case, you may use an ultrasonic disperser etc. together. The heating temperature is 40 to 140 ° C., and the heating time is 30 minutes to several hours. Then, a polymerization initiator is added to the dispersion, and the polymerizable monomer is suspension-polymerized in an aqueous medium to obtain a non-magnetic toner. The polymerization initiator used in the present invention is preferably soluble in the polymerizable monomer. Examples of such a polymerization initiator include 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azobis-4-methoxy-2, 4-
Examples thereof include dimethyl valeronitrile, other azo or diazo polymerization initiators; benzoyl peroxide, methyl ethyl ketone peroxide, isopropyl peroxy carbonate, and other peroxide polymerization initiators. In the present invention, it is preferable to use two or more of the above-mentioned polymerization initiators in combination for the purpose of controlling the molecular weight and the molecular weight distribution, or for controlling the reaction time. If necessary, a water-soluble polymerization initiator such as ammonium persulfate or potassium persulfate may be used together. The amount of the polymerization initiator used is usually 0.1 to 20 parts by weight, preferably 1 to 5 parts by weight, based on 100 parts by weight of the polymerizable monomer. If the amount of the polymerization initiator is less than 0.1 parts by weight, the molecular weight of the product polymer becomes so large that the properties as a non-magnetic toner are not satisfied, while if the amount of the polymerization initiator exceeds 20 parts by weight, the polymerization product is The molecular weight of is too low, which is not preferable.

The above suspension polymerization reaction is preferably carried out in the presence of a suspension stabilizer. Generally, in suspension polymerization, a surfactant having a hydrophilic group and a hydrophobic group in the molecule is often used as a suspension stabilizer. The suspension stabilizer has a polar group such as a hydroxyl group, a carboxyl group and a salt thereof, a sulfone group and a salt thereof as a hydrophilic group, and is composed of an apolar group such as an aliphatic or aromatic group as a hydrophobic group. Therefore, it has the ability to prevent coalescence of the monomer composition particles formed by the granulation step and stabilize them. Examples of such suspension stabilizers include polyvinyl alcohol, casein, gelatin, methyl cellulose, methyl hydroxypropyl cellulose, cellulose derivatives such as ethyl cellulose, starch and derivatives thereof,
Examples thereof include poly (meth) acrylic acid and salts thereof. These suspension stabilizers function to coat the surface of the droplets during the polymerization reaction and prevent coalescence and agglomeration of the droplets.

Further, in the production of the non-magnetic toner according to the present invention, a suspension polymerization may be carried out by adding a cross-linking agent such as divinylbenzene to improve blocking resistance and durability. Further, a charge control agent may be added if necessary. Such a charge control agent may be a nigrosine dye, a quaternary ammonium salt or the like if it has a positive charging property, and a metal of an organic compound having a carboxyl group, a sulfonate ester or a nitrogen-containing group if it has a negative charging property. There are complexes, metal-containing dyes and the like. In the present invention, the suspension polymerization reaction is usually
The polymerization temperature is 50 ° C. or higher, and the temperature is set in consideration of the decomposition temperature of the polymerization initiator. If the set temperature is too high, the polymerization initiator will be rapidly decomposed and the molecular weight and the like will be affected. In addition, neutral salts such as sodium chloride and sodium sulfate may be added to the aqueous medium for the purpose of preventing emulsification. Further, a thickener such as glycerin or ethylene glycol may be added for the purpose of preventing coalescence of the monomer composition particles formed in the granulation step.

The non-magnetic toner preferably has a volume average particle size of 12 μm or less, preferably 3 to 9.5 μm. If it is less than 3 μm, sufficient fluidity cannot be obtained. On the other hand, if it is larger than 9.5 μm, the reproducibility of pixels such as thin lines and characters deteriorates.

Next, the fine particles attached to the surface of the non-magnetic toner will be described in detail. The non-magnetic one-component developer that constitutes the present invention is one in which fine particles containing at least one selected from fine particles of cerium oxide or silicon carbide and magnetic particles are attached to the surface of the non-magnetic toner. The fine particles of cerium oxide or silicon carbide are preferably used in the range of 0.1 to 1 part by weight with respect to 100 parts by weight of the non-magnetic toner. If it is less than 0.1 part by weight, the polishing effect of the fine particles of cerium oxide or silicon carbide on the layer regulating member is insufficient, and the non-magnetic toner is likely to be fused to the layer regulating member. On the other hand, if the amount is more than 1 part by weight, the addition amount is excessive and the chargeability of the non-magnetic one-component developer may be hindered. The magnetic particles are preferably used in the range of 0.1 to 5 parts by weight with respect to 100 parts by weight of the non-magnetic toner. If the amount is less than 0.1 parts by weight, the polishing effect of the magnetic particles on the layer regulating member is insufficient and the non-magnetic toner is likely to be fused to the layer regulating member. On the other hand, if the amount is more than 5 parts by weight, the addition amount is excessive and the chargeability of the non-magnetic one-component developer may be hindered. As magnetic particles, spinel, perovskite, hexagonal crystal, garnet, ferrite having an orthoferrite structure, magnetite, and the like are applied crystallographically. The structure of ferrite is nickel, zinc, manganese, magnesium, copper, lithium, barium, vanadium, chromium,
It is a sintered body of oxide such as calcium and trivalent iron oxide. The particle diameter of cerium oxide or silicon carbide fine particles and magnetic particles is preferably in the range of 0.05 to 2 μm.
When it is less than 0.05 μm, the polishing effect on the layer regulating member is insufficient and the non-magnetic toner is apt to be fused to the layer regulating member. On the other hand, if it is larger than 2 μm, the adhesion to the non-magnetic toner particles may be poor, which may cause separation, scattering, or fog. Further, the fine particles to be adhered to the surface of the non-magnetic toner according to the present invention include, in addition to the cerium oxide, silicon carbide and magnetic particles, other fine particles such as hydrophobic alumina, carbon black and hydrophobic silica of the non-magnetic toner. You may mix and use it for the purpose of controlling triboelectric charging and controlling conductivity. However, in this case, it is desirable that the ratio of the specific particles composed of cerium oxide, silicon carbide and magnetic particles to the entire fine particles is 0.05% by weight or more.

As means for adhering fine particles containing cerium oxide, silicon carbide or magnetic particles to the surface of the non-magnetic toner, the non-magnetic toner and the above-mentioned particles are mixed at a predetermined ratio and a turbine type agitator or a Henschel mixer is used. ,
A method of stirring using a stirrer such as a super mixer may be mentioned. Further, as the stirring means, a device called a surface reformer such as Nara Hybridization System manufactured by Nara Machinery Co., Ltd. or Ongmill manufactured by Hosokawa Micron may be used. In the present invention, the particles attached to the surface of the non-magnetic toner means that the particles are sprinkled and attached to the surface of the non-magnetic toner, and at least the particles are attached to the surface of the non-magnetic toner. A part of it is buried and fixed. In this case, in order to embed and fix the particles, the surface modification means such as the Nara Hybridization System manufactured by Nara Machinery Co., Ltd. or the Ongmill manufactured by Hosokawa Micron Co., Ltd. is used.

[0016]

In order to prevent fusion of the non-magnetic one-component developer to the layer-regulating member, the non-magnetic one-component developer must have good lubricity when contacting and sliding with the layer-regulating member. Is. The non-magnetic toner according to the suspension polymerization method that constitutes the present invention is a spherical substance, and therefore has good lubricity due to its shape at the time of contact with the layer regulating member. Alternatively, by mixing and adhering at least one kind selected from fine particles of silicon carbide and magnetic particles, it becomes possible to prevent the non-magnetic toner from being fused to the layer regulating member by the developer. That is, in the pressure contact portion between the developing roller and the layer regulating member, the resin component of the non-magnetic one-component developer that is pressure-bonded to the layer regulating member and fused is polished by fine particles and magnetic particles of cerium oxide or silicon carbide, It is possible to prevent fusion of components constituting the developer.

[0017]

EXAMPLES The present invention will be described below based on examples. In the examples, “part” means “part by weight”. Example 1 20 g of stearyl peroxide was dissolved in a mixed solution of 800 g of styrene and 200 g of n-butyl acrylate, and 120 g of carbon black (# 40 manufactured by Mitsubishi Kasei Co., Ltd.).
Then, 30 g of a nigrosine dye (Bontron N04 manufactured by Orient Chemical Co., Ltd.) was added and stirred. The mixture was heated at 40 ° C. for 4 hours with further stirring. 25 g of 2,2'-azobisisobutyronitrile was added to the obtained slurry.
Were mixed and dissolved. Aqueous polyacrylic acid solution (Wako Pure Chemical Industries, Ltd., about 25%, 8000 to 12000 cp, 2 to this solution)
(5 ° C.) 80 g and sodium sulfate 45 g, distilled water 5
The solution dissolved in 000 g was added and stirred with a stirrer (Homomixer M type) at 10,000 rpm for 20 minutes to obtain a dispersion liquid containing a polymerizable monomer and a colorant. This dispersion was added to a 5 liter separable flask container equipped with a reflux tube. After purging the inside of the reaction vessel with nitrogen for 30 minutes, the mixture was stirred for 9 hours at 300 rpm with a stirrer having a turbine-type stirring blade with a diameter of 50 mm while heating to 95 ° C. Then, while maintaining stirring, the inner solution was cooled to room temperature, the polymer particles were filtered off, washed well with water and then dried to obtain a spherical non-magnetic toner. The particle size of the obtained spherical non-magnetic toner was measured with a Coulter counter (aperture 10
The volume average particle diameter of the non-magnetic toner was 6.2 μm. Next, to 100 parts of this non-magnetic toner, 0.1 part of fine particles of cerium oxide (particle size of Nikki Co., about 0.5 μm) was added,
The non-magnetic one-component developer used in the present invention was obtained by stirring for 2 minutes with a Henschel mixer.

Example 2 0.3 part of fine particles of cerium oxide (particle size: 0.5 μm, manufactured by Nikki Co.) and hydrophobic alumina (RFY-C, manufactured by Nippon Aerosil Co., Ltd.) were added to the non-magnetic toner of Example 1. .1
A nonmagnetic one-component developer used in the present invention was obtained in the same manner as in Example 1 except that 5 parts and 5 parts were simultaneously added.

Example 3 0.3 parts of fine particles of cerium oxide (particle size: 0.5 μm, manufactured by Nikki Co.) and carbon black (# 40 manufactured by Mitsubishi Kasei Kogyo Co., Ltd.) were added to the non-magnetic toner of Example 1. A non-magnetic one-component developer used in the present invention was obtained in the same manner as in Example 1 except that 1 part and 1 part were added at the same time.

Example 4 In the same manner as in Example 1 except that 0.1 part of fine particles of silicon carbide (particle diameter of about 0.5 μm, manufactured by Shiramizu Chemical Industry Co., Ltd.) was added to the non-magnetic toner of Example 1. A non-magnetic one-component developer used in the present invention was obtained.

Example 5 For the non-magnetic toner of Example 1, 0.3 parts of silicon carbide fine particles (particle diameter of about 0.5 μm, manufactured by Shiramizu Chemical Industry Co., Ltd.) and hydrophobic alumina (RFY-C, manufactured by Nippon Aerosil Co., Ltd.) were used. ) 0.
In the same manner as in Example 1 except that 15 parts and
A non-magnetic one-component developer used in the present invention was obtained.

Example 6 To the non-magnetic toner of Example 1, 0.2 parts of silicon carbide fine particles (particle diameter of about 0.5 μm, manufactured by Shiramizu Chemical Industry Co., Ltd.) and carbon black (# 40 manufactured by Mitsubishi Kasei Kogyo Co., Ltd.) were used. A non-magnetic one-component developer used in the present invention was obtained in the same manner as in Example 1 except that 0.1 part and 0.1 part were simultaneously added.

Example 7 In the same manner as in Example 1 except that 0.3 parts of magnetic particles (EPT-500 manufactured by Toda Kogyo Co., Ltd., particle size: about 0.5 μm) were added to the non-magnetic toner of Example 1. A non-magnetic one-component developer used in the present invention was obtained.

Example 8 For the non-magnetic toner of Example 1, 0.5 parts of magnetic particles (EPT-500 particle size of Toda Kogyo KK, about 0.5 μm) and hydrophobic alumina (RFY-C of Nippon Aerosil Co., Ltd.) were used. )
A non-magnetic one-component developer for use in the present invention was obtained in the same manner as in Example 1 except that 0.15 part was added at the same time.

Example 9 To the non-magnetic toner of Example 1, 0.5 part of magnetic particles (EPT-500 particle size of Toda Kogyo KK, about 0.5 μm) and carbon black (# 40 of Mitsubishi Kasei Kogyo KK) were added. 0.1
A non-magnetic one-component developer used in the present invention was obtained in the same manner as in Example 1 except that the parts and the components were added at the same time.

Comparative Example 1 Raw materials were mixed in the following formulation, and hot melt kneading was carried out in an extruder, followed by pulverization classification to obtain an average particle diameter of 6.5 μm.
m non-magnetic toner was obtained. The non-magnetic toner was directly used as a non-magnetic one-component developer for comparison.

Comparative Example 2 To 100 parts of the non-magnetic toner of Comparative Example 1, 0.3 part of hydrophobic alumina (RFY-C manufactured by Nippon Aerosil Co., Ltd.) was added and mixed in the same manner as in Example 1. Thus, a non-magnetic one-component developer for comparison was obtained.

Comparative Example 3 The non-magnetic toner of Example 1 was used as it was as a non-magnetic one-component developer for comparison.

Using the non-magnetic one-component developer obtained by the above operation, a commercially available magnetic printer (trade name: L-880 manufactured by Kyocera) having a developing mechanism shown in FIG. A print test was performed using a DC voltage of -100V and a surface potential of the photoconductor modified to -900V. In each of the non-magnetic one-component developers of Examples 1 to 9, the developer was not fused to the layer regulating member. On the other hand, in the non-magnetic one-component developers of Comparative Examples 1 to 3, the developer was fused to the layer regulating member and scattering occurred. Table 1 shows the results of the solid image of the non-magnetic one-component developer transferred from the photosensitive drum onto the transfer paper, measured by a Macbeth reflection densitometer, and the fog measured by the Hunter color difference meter on the non-image area. . As is clear from Table 1, it was confirmed that the non-magnetic one-component developing method of the present invention has sufficient image density and less fog than the comparative example.

[0030]

[Table 1]

[0031]

As described above, the present invention uses the non-magnetic one-component developer in which specific fine particles are mixed and adhered to the spherical non-magnetic toner obtained by the suspension polymerization method. There was no fusion and good development characteristics were obtained.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a non-contact type non-magnetic one-component developing device for carrying out the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photoconductor drum 2 Hopper 3 Non-magnetic one-component developer 4 Layer regulating member 5 Developing roller 6 Developer leakage prevention member 7 Stirrer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masahiro Maeda 3-1, Soba-cho, Shizuoka-shi, Shizuoka Prefecture Tomagawa Paper Mill Technical Research Institute

Claims (1)

[Claims] 1. A non-magnetic one-component developer is supplied to a developing roller, a thin layer of the non-magnetic one-component developer is formed on the surface of the developing roller by a layer regulating member, and an electric charge is applied to the developing roller and the photosensitive drum and the developing roller. A non-contact type non-magnetic one-component developing method in which the non-magnetic one-component developer is caused to fly by a potential difference between In the non-magnetic one-component developer, fine particles containing at least one selected from cerium oxide, silicon carbide and magnetic particles are attached to the surface of a non-magnetic toner obtained by a suspension polymerization method. A non-magnetic one-component developing method characterized by being present.