JP2750562B2 - Non-magnetic one-component development method - Google Patents

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 In general, in electrophotography, an electric latent image is formed on a photosensitive drum, the latent image is developed with toner, and a toner image is transferred to a transfer material such as paper as necessary. Thereafter, the image is fixed by means such as heating and pressing to obtain a copy. As a developer used in such an electrophotographic method, there are a two-component developer including a toner and a carrier, and a one-component developer having both functions of a toner and a carrier. One-component developers are further classified into magnetic one-component developers and non-magnetic one-component developers. The two-component developer has excellent electrophotographic properties such as transferability, fixability, and environmental resistance, but requires a toner concentration sensor to control the mixing ratio of toner and carrier, and has a short developer life. And a problem that the stirring mechanism of the developer becomes complicated. On the other hand, the magnetic one-component developer does not require the above-mentioned toner concentration sensor, and can easily reduce the size of the developing device, but has a problem that the fixing property is inferior because it contains magnetic particles. In view of such a background, a method using a non-magnetic toner as a one-component developer has recently been proposed and put into practical use in order to achieve both the simplification of the apparatus and the fixing characteristics.

A one-component developing method using a 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 to perform development. There is a non-contact type non-magnetic one-component developing method in which a certain gap is provided between a roller and a photosensitive drum to fly and develop non-magnetic toner on a developing roller. In the non-contact type non-magnetic one-component developing method, since the thin layer of the developer must be formed uniformly on the developing roller, the distance between the developer and the layer regulating member is designed to be very small. As a result, in the conventional non-magnetic one-component developing method, the mechanical load given to the developer is large, and the problem that the developer is fused to the layer regulating member due to frictional heat generated by the contact and sliding occurs. I was When the developer is fused to the layer regulating member, the triboelectricity of the developer is impaired, and the developer becomes difficult to be charged. As a result, the phenomenon that the developer adheres to the non-image area, that is, the fog or the developer This causes a problem of so-called scattering.

[0004]

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

[0005]

Means for Solving the Problems As a result of intensive studies, the present inventors have used a spherical toner produced by a suspension polymerization method as a non-magnetic one-component developer, and further provided a fine particle of metal stearate on the surface of the spherical toner. By mixing and adhering an external additive containing resin particles or silicone oil, it has been found that a non-magnetic one-component developing method having good developability without toner fusion to the layer regulating member, which is the above object, can be provided. Thus, the present invention has been completed. That is, in 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 a charge is given to the photosensitive drum. 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 from a roller and developed in a non-contact manner on a photosensitive drum holding an electrostatic latent image, and then transferred to a transfer material. An external additive wherein the non-magnetic one-component developer contains at least one selected from fine particles of metal stearate, resin particles and silicone oil on the surface of the non-magnetic toner obtained by the suspension polymerization method. Is a non-magnetic one-component developing method, wherein

Hereinafter, the present invention will be described in detail. FIG.
FIG. 1 is a schematic configuration diagram of a developing device used in a non-contact 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 that carries the non-magnetic one-component developer, and 6 is a non-magnetic one-component developer leakage prevention member. , 7 are agitators. 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. The non-magnetic one-component developer 3 is supported on the developing roller 5 by a layer regulating member 4 so as to have a constant layer thickness. Electric charge is applied by friction with the regulating member 4. The developing roller 5 is provided with a gap of 120 μm to 300 μm with the photosensitive drum 1. 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 transported by the rotation of the developing roller 5 and flies to the surface of the photosensitive drum 1 due to a potential difference between the photosensitive drum 1 having an electrostatic latent image and the developing roller 5. Then, the electrostatic latent image is visualized in a non-contact manner.

Next, the non-magnetic toner constituting the non-magnetic one-component developer according to the present invention will be described in detail. The non-magnetic toner is colored particles obtained by adding a polymerization initiator to a dispersion in which a colorant is dispersed in a polymerizable monomer, and then subjecting the polymerizable monomer to suspension polymerization 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 such as styrene, pn-hexylstyrene, pn-octylstyrene, pn-nonylstyrene, pn-decylstyrene and derivatives thereof; ethylene-unsaturated monoolefins such as ethylene, propylene, butylene, and isobutylene Vinyl halides such as vinyl chloride, vinylidene chloride, vinyl bromide and vinyl fluoride; organic acid vinyl esters such as vinyl acetate, vinyl propionate and vinyl benzoate; methacrylic acid, methyl methacrylate, and ethyl methacrylate , Propyl methacrylate, n-butyl methacrylate, Acrylic acid n- octyl, dodecyl methacrylate, 2-ethylhexyl methacrylate,
Methacrylic acid such as stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate and derivatives thereof; 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 and phenyl acrylate; vinyl ethers such as vinyl methyl ether, vinyl ethyl ether and vinyl isobutyl ether; vinyl methyl ketone and vinyl hexyl ketone And vinyl ketones such as vinyl isopropenyl ketone; N-vinyl compounds such as N-vinyl pyrrole, N-vinyl carbazole, N-vinyl indole and N-vinyl pyrrolidone; vinyl naphthalenes; acrylonitrile, methacrylonitrile, acrylamide and the like. These monomers are used alone or in combination of two or more. It is preferable to use styrene or a styrene derivative alone or as a mixture with another monomer in order to enhance the environmental characteristics and durability of the non-magnetic toner.

Examples of the colorant include black colorants such as carbon black, acetylene black, lamp black, channel black, and aniline black;
If a chromatic color, there may be mentioned Farnal Blue, Permanent Blue, Nigrosine Blue, phthalocyanine cyan pigment, rose bengal, xanthene magenta dye, quinacridone magenta pigment, monoazo red pigment, disazo yellow pigment, etc. 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 containing a polymerizable monomer and a colorant is prepared. At this time, it is preferable to add an organic peroxide to the dispersion 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 an organic peroxide include the following compounds. Stearyl peroxide, palmityl peroxide, behenyl peroxide, myristyl peroxide, stearyl peroxyphenoxy acetate, myristyl peroxyphenoxy acetate, α-
Cumyl peroxystearate, α-cumyl peroxy myristate, t-butyl peroxystearate,
t-butyl peroxymyristylate, α-cumyl peroxybehenate, α-cumyl peroxycetylate,
t-butyl peroxybehenate, t-butyl peroxycetylate and the like. The amount of the organic peroxide to be 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 with stirring is used. In that case, you may use an ultrasonic dispersion machine etc. together. The heating temperature is 40-140 ° C, and the heating time is 30 minutes to several hours. Next, when a polymerization initiator is added to the dispersion and the polymerizable monomer is subjected to suspension polymerization in an aqueous medium, a non-magnetic toner is obtained. The polymerization initiator used in the present invention is preferably soluble in a 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-
Dimethyl valeronitrile, other azo-based or diazo-based polymerization initiators, such as benzoyl peroxide, methyl ethyl ketone peroxide, isopropyl peroxycarbonate, and other peroxide-based polymerization initiators. In the present invention, it is preferable to use a combination of two or more of the above-mentioned polymerization initiators for the purpose of controlling the molecular weight and the molecular weight distribution or controlling the reaction time. If necessary, a water-soluble polymerization initiator such as ammonium persulfate and potassium persulfate may be used in combination. The amount of the polymerization initiator to be used is generally 0.1 to 20 parts by weight, preferably 1 to 5 parts by weight, based on 100 parts by weight of the polymerizable monomer. When the polymerization initiator is less than 0.1 part by weight, the molecular weight of the product polymer becomes so large that the molecular weight of the product polymer does not satisfy the properties as a non-magnetic toner. On the other hand, when the polymerization initiator exceeds 20 parts by weight, the polymerization product Is not preferred because the molecular weight becomes too low.

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 a 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 a nonpolar group such as an aliphatic group and an aromatic group as a hydrophobic group. And has the ability to prevent and stabilize the coalescence of the monomer composition particles formed by the granulation process. 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.

In producing the nonmagnetic toner of the present invention, a crosslinking agent such as divinylbenzene may be added for suspension polymerization in order to improve blocking resistance and durability. Further, if necessary, a charge control agent may be added. Examples of such a charge control agent include a nigrosine dye, a quaternary ammonium salt or the like if it is positively chargeable, and a metal of an organic compound having a carboxyl group, a sulfonate or a nitrogen-containing group if it is negatively chargeable. Complexes, metal-containing dyes and the like. In the present invention, the suspension polymerization reaction is usually carried out by
The polymerization is performed at a polymerization temperature of 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 is rapidly decomposed, which affects the molecular weight and the like, which is not preferable. In addition, neutral salts such as sodium chloride and sodium sulfate may be added to the aqueous medium for the purpose of preventing emulsification. For the purpose of preventing coalescence of the monomer composition particles formed in the granulation step, a thickener such as glycerin or ethylene glycol may be added.

The above non-magnetic toner preferably has a volume average particle diameter 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 fine lines and characters deteriorates.

Next, the external additives such as fine particles adhered to the surface of the non-magnetic toner will be described in detail. In the non-magnetic one-component developer constituting the present invention, an external additive containing at least one selected from fine particles of metal stearate, resin particles or silicone oil is adhered to the surface of the non-magnetic toner. It is. Examples of the fine particles of the metal stearate include fine particles of aluminum stearate, barium stearate, calcium stearate, zinc stearate, magnesium stearate, lithium stearate, lead stearate, and the like. Further, as the resin particles, polystyrene resin, acrylic resin, styrene-acrylate resin, polyester resin, polypropylene resin, epoxy resin, phenol resin, melamine resin, benzoguanamine resin, silicone resin,
Fine particles such as nylon resin. The particle diameter of the fine particles of the metal stearate and the resin particles is preferably in the range of 0.1 to 3 μm. If it is less than 0.1 μm, the dispersibility in the non-magnetic toner is poor, the fluidity as a developer is poor, and it is difficult to form a thin layer on the surface of the developing roller. On the other hand, 3 μm
If it is larger, the adhesion to the non-magnetic toner particles is poor, which may cause separation, scattering, or fogging. The content of the metal stearic acid fine particles and the resin particles is preferably 0.05 to 3 parts by weight based on 100 parts by weight of the non-magnetic toner.
If the amount is less than 0.05 part by weight, the lubricating effect of the fine particles on the layer regulating member is insufficient, and the non-magnetic toner is easily fused to the layer regulating member. On the other hand, if it is more than 3 parts by weight, the addition is excessive, and the chargeability of the non-magnetic one-component developer may be hindered.

Next, the following silicone oils can be used in the present invention. That is, monomethyl silicone oil, dimethyl silicone oil and the following silicone oil modified from dimethyl silicone oil: methylstyrene or olefin-modified silicone oil, polyether-modified silicone oil, alcohol-modified silicone oil, fluorine-modified silicone oil, amino-modified silicone oil And silicone oils modified with mercapto, epoxy modified silicone oil, carboxyl modified silicone oil, higher fatty acid modified silicone oil, carnauba modified silicone oil and amide modified silicone oil. The silicone oil is used in an amount of 0.05 to 2 parts by weight, preferably 0.1 to 1 part by weight, based on 100 parts by weight of the nonmagnetic toner. When the amount is less than 0.05 parts by weight, the lubricating effect of the silicone oil on the layer regulating member is insufficient, and the non-magnetic toner is easily fused to the layer regulating member. On the other hand, if it is more than 2 parts by weight, the addition is excessive, the non-magnetic toner tends to aggregate, the fluidity deteriorates, and it is difficult to form a thin layer on the surface of the developing roller. The viscosity of silicone oil is 1 ~ 300CS
Is appropriate. If it is less than 1 CS, the lubricating effect of the silicone oil on the layer regulating member is insufficient, and the non-magnetic toner is easily fused to the layer regulating member. On the other hand, if it is 300 CS or more, the adhesion to the non-magnetic toner particles is poor, which may cause separation, scattering, or fogging. Further, the external additive to be adhered to the surface of the non-magnetic toner according to the present invention, besides the above-mentioned metal stearate fine particles, resin particles or silicone oil, for example, hydrophobic alumina, carbon black, hydrophobic silica and other other additives Fine particles may be mixed and used for the purpose of controlling triboelectric charging and conductivity of the non-magnetic toner. However, in this case, it is desirable that the ratio of the specific external additive composed of fine particles of metal stearate, resin particles or silicone oil to the total fine particles is 0.05% by weight or more.

As a means for adhering an external additive containing fine particles of metal stearate, resin particles or silicone oil to the surface of the nonmagnetic toner, the nonmagnetic toner and the external additive are mixed at a predetermined ratio. Turbine agitator,
Examples thereof include a method of stirring using a stirrer such as a Henschel mixer or a super mixer. Further, as the stirring means, a device called a surface reforming machine such as a Nara hybridization system manufactured by Nara Machinery Co., Ltd. or an angmill manufactured by Hosokawa Micron Corporation may be used. In the present invention, the expression that the external additive is attached to the surface of the non-magnetic toner means that the external additive is sprayed on the surface of the non-magnetic toner and that the external additive is attached to the surface of the non-magnetic toner. A state in which at least a part of the external additive is embedded and fixed. In this case, in order to embed and fix the external additive, a surface modifying means such as the above-mentioned Nara Hybridization System manufactured by Nara Machinery Co., Ltd. or Ongmill manufactured by Hosokawa Micron Corporation is used.

[0017]

In order to prevent the non-magnetic one-component developer from being fused to the layer regulating member, the non-magnetic one-component developer needs to have good lubricity in contact and sliding with the layer regulating member. It is. The non-magnetic toner according to the suspension polymerization method that constitutes the present invention has good lubricity at the time of contact with the layer regulating member due to its shape because it is a spherical substance. By mixing and adhering at least one selected from fine particles of metal stearic acid, resin particles and silicone oil, it is possible to prevent the developer from fusing the non-magnetic toner to the layer regulating member. That is, since fine particles of metal stearate, resin particles or silicone oil adhere to the surface of the non-magnetic toner, the fine particles of metal stearate, resin particles or silicone oil adhere between the non-magnetic toner and the layer regulating member. The effect of lubricating oil is exhibited, and the lubricity of the non-magnetic toner is improved. Therefore, the fusion of the developer can be prevented.

[0018]

The present invention will be described below with reference to examples. In the examples, parts are parts 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 (Mitsubishi Kasei Industries # 40) was further dissolved.
And 30 g of a nigrosine dye (Bontron N04 manufactured by Orient Chemical Co., Ltd.) were added and stirred. With further stirring, the mixture was heated at 40 ° C. for 4 hours. 25 g of 2,2′-azobisisobutyronitrile was added to the obtained slurry.
Was mixed and dissolved. To this solution was added a polyacrylic acid aqueous solution (manufactured by Wako Pure Chemical Industries, Ltd., about 25%, 8000 to 12000 cp, 2
5 ° C.) 80 g and sodium sulfate 45 g were mixed with distilled water 5
A solution dissolved in 000 g was added, and the mixture was stirred at 10,000 rpm for 20 minutes with a stirrer (Homomixer M type) to obtain a dispersion containing a polymerizable monomer and a colorant. This dispersion was added to a 5-liter separable flask equipped with a reflux tube. After the inside of the reaction vessel was replaced with nitrogen for 30 minutes, the mixture was stirred at 300 rpm for 9 hours with a stirrer having a turbine-type stirring blade having a diameter of 50 mm while heating to 95 ° C. Thereafter, while maintaining the stirring, the inner solution was cooled to room temperature, the polymer particles were separated by filtration, washed well with water, and dried to obtain a spherical non-magnetic toner. The particle diameter of the obtained spherical non-magnetic toner is measured with a Coulter counter (aperture 10).
0 μm), the volume average particle diameter of the non-magnetic toner was 6.2 μm. Next, with respect to 100 parts of the non-magnetic toner, fine particles of aluminum stearate (particle size: about 0.5 μm, manufactured by Tannan Chemical Industry Co., Ltd.)
0.15 was added, and the mixture was stirred with a Henschel mixer for 2 minutes to obtain a non-magnetic one-component developer used in the present invention.

Example 2 Fine particles of aluminum stearate (manufactured by Tannan Chemical Industry Co., Ltd., having a particle diameter of about 0.5 μm) were used for the non-magnetic toner of Example 1.
m) A non-magnetic one-component developer used in the present invention was obtained in the same manner as in Example 1 except that 0.35 part and hydrophobic alumina (RFY-C manufactured by Nippon Aerosil Co., Ltd., 0.15 part) were simultaneously added. Was.

Example 3 Fine particles of aluminum stearate (manufactured by Tannan Chemical Industry Co., Ltd., having a particle diameter of about 0.5 μm) were used for the non-magnetic toner of Example 1.
m) 0.3 parts and carbon black (Mitsubishi Kasei Kogyo Co., Ltd.)
# 40) 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 was simultaneously added.

Example 4 Example 1 was repeated except that 0.1 part of a styrene-methyl methacrylate copolymer resin (a particle diameter of about 0.3 μm, manufactured by Soken Chemical Co., Ltd.) was added to the non-magnetic toner of Example 1. In the same manner as in the above, a non-magnetic one-component developer used in the present invention was obtained.

Example 5 To the non-magnetic toner of Example 1, 0.35 part of a styrene-methyl methacrylate copolymer resin (particle size: about 0.3 μm, manufactured by Soken Chemical Co.) and hydrophobic alumina (Nippon Aerosil Co., Ltd.) RFY-C) (0.25 parts) was obtained in the same manner as in Example 1 except that 0.25 parts of the nonmagnetic one-component developer used in the present invention was obtained.

Example 6 To the non-magnetic toner of Example 1, 0.35 parts of a styrene-methyl methacrylate copolymer resin (manufactured by Soken Chemical Co., Ltd., particle size: about 0.3 μm) and carbon black (Mitsubishi Kasei Kogyo Co., Ltd.) # 40) 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 of the developer was simultaneously added.

Example 7 A dimethyl silicone oil (KF-96-3025 manufactured by Shin-Etsu Silicone Co., Ltd.) was used for the non-magnetic toner of Example 1.
(Viscosity at 30 ° C .: 30 CS) 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 of a developer was added.

Example 8 Dimethyl silicone oil (KF-96-3025 manufactured by Shin-Etsu Silicone Co., Ltd.) was used for the non-magnetic toner of Example 1.
Viscosity at 30 ° C .: 30 CS) and 0.15 part of hydrophobic alumina (RFY-C, manufactured by Nippon Aerosil Co., Ltd.) were simultaneously added in the same manner as in Example 1 except that non-magnetic particles used in the present invention were added. A component developer was obtained.

Example 9 The nonmagnetic toner of Example 1 was replaced with dimethyl silicone oil (KF-96-3025 manufactured by Shin-Etsu Silicone Co., Ltd.).
Viscosity at 30 ° C .: 30 CS) 0.35 parts of carbon black (Mitsubishi Kasei Kogyo Co., Ltd. # 40) 0.1 part was simultaneously added except that the non-magnetic one component used in the present invention was used. A developer was obtained.

COMPARATIVE EXAMPLE 1 Raw materials were mixed in the following composition, hot melt kneaded with an extruder, and then pulverized and classified to have an average particle diameter of 6.5 μm.
m of non-magnetic toner was obtained. The non-magnetic toner was 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 directly used as a non-magnetic one-component developer for comparison. Comparative Example 4 To 100 parts by weight of the nonmagnetic toner of Example 1, 0.3 part of hydrophobic silica (R-972 manufactured by Nippon Aerosil Co., Ltd.) was added and mixed in the same manner as in Example 1. A comparative non-magnetic one-component developer was obtained. Comparative Example 5 To 100 parts by weight of the nonmagnetic toner of 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. A comparative non-magnetic one-component developer was obtained.

Using a non-magnetic one-component developer obtained by the above operation, a remodeling machine (developing bias for a commercially available magnetic printer (trade name: L-880, manufactured by Kyocera Corporation) having a developing mechanism shown in FIG. A print test was carried out using a DC voltage of -100 V and a surface potential of the photoconductor modified to -900 V). In each of the non-magnetic one-component developers of Examples 1 to 9, the developer did not fuse 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 scattered. Table 1 shows the results obtained by measuring the solid image of the non-magnetic one-component developer transferred from the photosensitive drum onto the transfer paper with a Macbeth reflection densitometer and the fog results of measuring the non-image portion with a Hunter colorimeter. . As is clear from Table 1, it was confirmed that the non-magnetic one-component developing method of the present invention had a sufficient image density and reduced fog as compared with the comparative example.

[0031]

[Table 1]

[0032]

According to the present invention, as described above, a non-magnetic one-component developer in which a specific external additive is mixed and adhered to a spherical non-magnetic toner by a suspension polymerization method is used to develop a toner on a layer regulating member. There was no fusion of the agent and good development characteristics were obtained.

[Brief description of the drawings]

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

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 photoconductor drum 2 hopper 3 non-magnetic one-component developer 4 layer regulating member 5 developing roller 6 developer leakage preventing member 7 stirrer

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-9070 (JP, A) JP-A-3-77960 (JP, A) JP-A-5-313416 (JP, A) 110246 (JP, A) JP-A-60-179748 (JP, A) JP-A-53-81127 (JP, A)

Claims (1)

(57) [Claims] 1. A non-magnetic one-component developer is supplied to a developing roller, and a thin layer of the non-magnetic one-component developer is formed on a surface of the developing roller by a layer regulating member and is given an electric charge. 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 with the photosensitive drum holding an electrostatic latent image in a non-contact manner, and then transferred to a transfer material. An external additive containing at least one selected from fine particles of metal stearate, resin particles and silicone oil on the surface of the non-magnetic toner obtained by the suspension polymerization method. A non-magnetic one-component developing method characterized by being adhered.