JPS59197066A - Applying method - Google Patents

Abstract

PURPOSE:To form a uniform thin layer of a developer on the surface of a developer holding member by using magnetic particles carrying a fine silica powder, which has the triboelectricity of the same polarity as a nonmagnetic developer, on the surface. CONSTITUTION:When a sleeve 2 is rotated, magnetic particles and the nonmagnetic developer are agitated and mixed while holding a magnetic brush 8 as it is. In the magnetic blade side of a vessel 3 in this state, the mixture of the developer and nonmagnetic particles is prevented from moving by the blade 6 and rises and is moved circularly in the direction of an arrow (c). Then, the nonmagnetic developer is triboelectrified with the sleeve 2 or magnetic particles by mixing with magnetic particles. The triboelectrified developer is applied uniformly thinly onto the surface of the sleeve 2 with the magnetic brush 8, which is formed near the magnetic blade 6, by an image force and reaches a position facing a photosensitive drum. In this method, magnetic particles carrying a fine silica powder are used to adjust physical properties of said developer, and a good application state is attained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a coating method for developing an electrostatic latent image using a non-magnetic developer.

Conventionally, various types of dry-component developing devices have been proposed and put into practical use. However, in any of the development methods, it is extremely difficult to form a thin layer of dry component developer, and for this reason, a developing device has been configured with a relatively thick layer.

However, as improvements in the clarity and resolution of developed images are currently being sought, it is essential to develop a method for forming a thin layer of a dry component developer and an apparatus therefor.

■ Conventionally known dry method - Thin layer of component developer! As a forming method, Japanese Patent Application Laid-Open No. 54-43037 has been proposed.
And it has been put into practical use. However, this concerned the formation of a thin layer of magnetic developer. Magnetic developers must have a magnetic material added to them in order to have magnetism, which causes poor fixing properties when heat fixing the developed image transferred to transfer paper, and adding magnetic material to the developer itself. There are problems such as poor color reproduction during color reproduction.

Therefore, methods for forming a thin layer of non-magnetic developer include a method in which a cylindrical brush made of soft bristles such as beaver hair is used to adhere the developer to the brush, and a method in which the surface is made of fibers such as velvet. A method has been proposed in which a doctor blade or the like is used to coat the developing roller. However, when an elastic blade is used as a doctor blade for the above-mentioned fiber brush, it is possible to regulate the amount of developer, but uniform application is not achieved, and the fibers of the brush are simply rubbed by the fiber brush on the developing roller. Since no triboelectric charge is imparted to the developer present in between, there is a problem in that ghosts and the like are likely to occur. Furthermore, since the device includes a non-magnetic developer, it is difficult to prevent the developer from leaking from the device.

The present invention eliminates the problems of the conventional method described above, and provides a new coating method in which the developer is formed as a uniform thin layer on the surface of a developer holding member, and is coated with sufficient triboelectric charging. The purpose is A further object of the present invention is to make it possible to prevent the non-magnetic developer from leaking out of the developing device.

The coating method of the present invention that achieves the above object includes a container for storing a non-magnetic developer and magnetic particles, a developer holding member for rotatably conveying the non-magnetic developer to a latent image carrier, and a non-magnetic developer for the container. A regulating member disposed on the magnetic developer supply outlet side with a gap formed on the surface of the holding member, and a regulating member disposed on the opposite side of the regulating member across the holding member, which controls the development of the container. and a magnet having at least one magnetic pole forming a magnetic brush of magnetic particles on the upstream side of the regulating member on the developer outlet side, and forming a thin layer of non-magnetic developer on the holding portion. In the force method, the method is characterized by the use of magnetic particles whose surfaces carry fine silica powder having triboelectric charging properties of the same polarity as that of the non-magnetic developer. With the method according to the present invention, not only can the advantages of all one-component jumbling development as shown in JP-A No. 54-043037 be utilized, but also the developer can be used even if a non-magnetic developer is used. Can be applied neatly onto the carrier.

Furthermore, in the method of the present invention, the adhesion and releasability of the non-magnetic developer and magnetic particles, and the triboelectricity and fluidity of the non-magnetic developer greatly affect coating and development. By using magnetic particles carrying fine silica powder having triboelectric charging properties of the same polarity, it is possible to adjust the physical properties of the developer and achieve a good coating state.

The polarity of the non-magnetic developer and the fine silica powder was determined by a blow-off method using iron powder as a reference.

The latent image carrier of the present invention may be a drum-shaped or belt-shaped member having a photoreceptor or an insulating layer, and the magnetic poles are fully magnetized with the same polarity or different polarity in the axial direction of the magnetic roller. Alternatively, a plurality of rod-shaped magnets bonded onto a fixed support member may be used. Furthermore, as the rotating developer holding member, it is possible to use a sleeve made of non-magnetic metal such as aluminum, copper, stainless steel, brass, etc. or a synthetic resin material, or an endless belt made of resin or metal. In order to improve the electrostatic properties and charging characteristics, the surface may be roughened or provided with an uneven pattern, if necessary. Further, as the regulating member, a blade plate or a wall made of a magnetic material such as iron or a non-magnetic material such as aluminum, copper, or resin may be used.

Hereinafter, the present invention will be explained in more detail with reference to the drawings.

FIG. 1 shows a sectional view of a developing device for explaining the developing principle to which the coating method of the present invention is applied.

In the figure, reference numeral 1 denotes an electrophotographic photosensitive drum, which holds a latent image formed by a latent image forming means (not shown), and rotates in the direction of arrow a to pass through a developing position shown in the drawing. A non-magnetic sleeve 2, which is a developer holding member for holding developer, faces the photosensitive drum 1 with a predetermined gap therebetween, and the sleeve 2 rotates in the direction of the arrow. A container 3 made of a non-magnetic material such as resin or aluminum is located above the sleeve 2 and stores a mixture of a non-magnetic developer 4 and magnetic particles 5, and downstream of the container 3 in the rotational direction of the sleeve, A magnetic blade 6 is screwed.

On the other hand, a magnet 7 is provided on the opposite side of the sleeve 2 to the magnetic blade 6. The position of this magnet is determined by the position of the magnetic poles and the effect of the magnetic field formed by the magnetic plate, resulting in better results in terms of preventing magnetic particles from flowing out and uniformly applying the developer.

In the above configuration, the magnetic particles 5 in the container 3 form a magnetic brush 8 due to the magnetic field generated between the S pole of the magnet 7 and the magnetic blade 6. As the sleeve 2 rotates, the magnetic particles and non-magnetic developer are stirred and mixed while the magnetic brush 8 is held. In this state, on the magnetic blade side of the container 3, due to the presence of the blade 6, the mixture of developer and non-magnetic particles is prevented from moving by the blade, rises, and circulates in the direction of arrow C.

As a result, the non-magnetic developer is charged by friction with the magnetic particles. The charged developer is uniformly and thinly applied to the surface of the sleeve 20 by a mirror force by a magnetic brush 8 formed near the magnetic blade 6, and reaches a position facing the photoreceptor drum.

By the way, the magnetic particles 5 constituting the magnetic brush 8 do not flow onto the sleeve 2 by setting the restraining force due to the magnetic field of the magnet 7 to be stronger than the conveying force caused by the frictional force. If there is non-magnetic developer within the area of the magnetic brush 8, the ratio of the magnetic particles of the magnetic brush 8 to this developer remains approximately constant as the sleeve 2 rotates.

This way, even if the developer on the sleeve is consumed during development,
Developer is automatically supplied to the area of the magnetic brush 8. Therefore, it is possible to always supply and apply a constant amount of developer onto the sleeve 2.

In the above principle explanation, a magnetic blade is used as the regulating member, but a non-magnetic blade or a wall made of a non-magnetic material such as resin or aluminum constituting the container can also be used as the regulating member.

However, in this case, in order to prevent the magnetic particles from flowing out, it is necessary to make the gap between the sleeve and the regulating member even smaller than when using a magnetic blade. Further, when a magnetic blade is used, it is preferable because a magnetic brush can be stably formed at the developer outlet by the magnetic field between the blade and the magnetic pole.

By the way, in the developing device shown in FIG. 1, since the developer is a non-magnetic developer, there may be a problem that it tends to leak from the region d on the side where the sleeve 2 enters the container 3.

In order to prevent the developer from leaking from the area d, a magnetic brush may be formed between the sleeve and the container on the side where the sleeve enters the container.

The silica fine powder used in the present invention may be produced by any method such as dry silica or wet silica.

For example, dry process silica is produced by vapor phase oxidation of silicon halogen compounds, so-called dry process silica or fumed silica, which is produced by conventionally known techniques. be. For example, this method utilizes a thermal decomposition oxidation reaction of silicon tetrachloride gas in an oxyhydrogen flame, and the basic reaction formula is as follows.

5iCA4 +2H, @-Ox→5ift + 4HQ
l! In addition, in this manufacturing process, for example, by using other metal halide compounds such as aluminum chloride or titanium chloride together with a silicon halide compound, it is also possible to obtain a composite fine powder of silica and other metal oxides. Also includes.

The average primary particle size of the particles is desirably within the range of o, ooi to 2μ, particularly preferably 0.00μ.
It is preferable to use silica fine powder within the range of 2 to 0.2 microns.

Examples of commercially available silica fine powders include those sold under the following trade names.

AERO3IL +130 (Japan Aerosil Co., Ltd.) 20000 80 T600 OX80 MOX 170 0K84 Cab -0-Sin M -5 (CA
BOT) MS-7 5-75 S-5 H-5 Wacker HDK N 20 (W
ACKER-CHEMIE V15GMBH) N20E 30 40 D CFind 5ilica (Tau Corning) pransol (Fransi7) As wet silica, various conventionally known methods can be applied. For example, the decomposition of sodium silicate with an acid can be expressed as a general reaction formula (the reaction formula is omitted below): Nb0- x8i0t + H(J+HtO-+ 5i
Oz・nH2O-1-NaCl and other decomposition of sodium silicate with ammonia salts or alkali salts, a method of generating alkaline earth metal silicate from sodium silicate and then decomposing it with acid to produce silicic acid, silicic acid There are methods such as converting a sodium solution into silicic acid using an ion exchange resin, and methods using natural silicic acid or silicate.

In addition, silicates such as aluminum silicate, sodium silicate, potassium silicate, magnesium silicate, and zinc silicate can be used.

Examples of commercially available products include Nip Seal Nippon Silica Toku Seal, Fine Seal, and Tokuyama Vita Vita Seal.
Polyurethane fertilizer Jiruton, Silnenox Mizusawa Kagaku Starsil
Kamishima Kagaku Himezil Ehime Yakuhin Thyroid Fuji Davison Kagaku Hi-sil Pittsbu
rgh plate Glass CO.

(Pittsburgh plate glass.

1) urosil (Do D Sea/l/) Fii
llstoff-Gesellschaft Marq
uart' (Jltrasil (Ultrasil) (Fyurstonov Gevzurenyaft i Otsuruzuze Osoret) Manosil (-rnosy/l/) Hard
man and ho1den
Holden) HOeSCh (Herash) Qhemisch
e Fabrik Hoesch K-G (Hiemische Fabrik Hoesch) Sfl-8tone (Siri>xto-y) 5to
ner Rubber Co.

(Stoner Lover) Halco (Narnia) Na1co Ch
em Co.

(Narco Chemical) Quso (Riso) philadel
phia Quartz Co.

(Philadelphia Quartz) 3antocell (Santo-vshi) M
on5anto-chainical Co.

(Monsanto Chemical) Imail l1linois
Minerals Co.

(Isonois Mineral) Calcium Sil 1kat (:h
em 1scbe R mountain rik Hoesch K-G
(Calcium Silicato) (Hiemi Soche Faf”
J-ri Herash)) Calsil Fiillstoff-Gesell
schaftMarquart (written by Fürstsfu) 1;'ortafil (phono filter) 1. imperial C
chemical industries, Ltd.

(Inbe1rJ) Rechemical Inkstries) Mic
local Joseph Cro
sfield & 5ons, Ltd.

Kujiesef Crossfield and Sons〉Mano
sil (manoshi/l/) Hardna
n and Ho1den (Hardman and Holden) ■ulkasil (7'A$ seal) F
arbenfabiken 13ryer+A,-G
.

Tufkn
it (tough knit) Durham
Chemicals, I, td.

(Doulham Chemicals) Silmos Shiraishi Industry Starex Kamishima Chemical Furikosil Multi-wooden fertilizer etc.

These fine silica powders may be used alone as they are, or may be subjected to some treatment in consideration of chargeability and hydrophobicity. Possible treatments include adding alumina, titanium oxide, etc. It is also possible to treat with a silane coupling agent.

Examples of silane coupling agents include those represented by the following general formula.

Si Yn (R is a hydrogen alkoxy group or a halogen atom, mtd1
An integer of ~3, Y is an amino group, a vinyl group, a glycidoxy group, a mercapto group, a methacrylic group, an alkyl group, an alkenyl group, an alkynyl group, an ester group, an alkoxycarbonyl group, an aromatic hydrocarbon group, a substituted aromatic hydrocarbon group , alkylmercapto group, acyl group, acylamino group, nitro group, imino group, phenylimino group, cyano group, substituted azo group, diazoamino group, ureido group, oxo group, straight or heterocyclic group, n is 1 to 3 (integer) Also, treatment with a titanate-based coupling agent is also possible.

As the hydrophobic treatment, for example, there is a method of treatment with an organosilicon compound. Examples of such organosilicon compounds are hexamethyldisilane, trimethylsilane, trimethylchlorosilane, trimethylethoxysicine, dimethyldichlorosilane, methyltrichlorosilane, allyldimethylchlorosilane, allyl phenyldichlorosilane, benzyldimethylchlorosilane. Silane, bromomethyldimethylchlorosilane, α-chloroethyltrichlorosilane, silkworm-chloroethyltrichlorosilane, ゛・-chloromethyldimethylchlorosilane, triorganosilylmercaptan, trimethylsilylmercaptan, triorganosilylacrylate, vinyldimethylacetoxysilane, dimethyl Ethoxysilane, dimethyldimethoxysilane, hexamethyldisiloxane, 1,3-divinyltetramethyldisiloxane, 1,3-diphenyltetramethyldisiloxane, and terminally located siloxane units with 2 to 12 siloxane units per molecule. 1 for each unit
Examples include dimethylpolysiloxane and amino-modified silicone oil containing hydroxyl groups bonded to specific Sl.

These may be used alone or in a mixture of two or more.

Furthermore, the above treatments can be used in combination of two or more types.

It is also possible to adjust the amount of adsorbed water and the number of hydroxyl groups by heat treating at a temperature of 400° C. or higher before and after the above treatment.

The silica fine powder described above may be selected to have the same polarity as the non-magnetic developer depending on its charging polarity.

Any method can be used to support the silica fine powder on the magnetic particles, and the silica fine powder may be supported alone or dispersed in a resin or the like. Generally, silica fine powder alone is mixed with a Henschel mixer, V
External addition using a mold mixer or the like is sufficient.

The amount added at this time may be appropriately determined depending on the particle size of the magnetic particles, the particle size of the fine silica powder, etc., but approximately 100% of the magnetic particles are added.
A suitable proportion is 0.1 to 5 parts by weight. If it is less than that, the improvement in the fluidity of the entire developer and the release effect between the non-magnetic developer and the magnetic particles will not be sufficient, and if it is more than that, too much fine silica powder will adhere to the surface of the non-magnetic developer. Problems such as deterioration of fixing properties and deterioration of images due to silica contamination of the developer carrier occur.

It is also possible to have the surface of the non-magnetic developer carry fine silica powder that is the same as or different from the surface of the persimmon particles.

Examples of the magnetic particles include metals such as iron, nickel, cobalt, manganese, and chromium rare earths, which are surface oxidized or oxidized to Tl, and alloys thereof, or oxides thereof;
For example, magnetite, ferrite, rare earth metal oxide, etc. are used.The shape of the tag may be spherical, flat, or acicular. Further, these magnetic particles may be coated with a resin or a surface treatment agent.

The binder resin for the non-magnetic developer used in the present invention is as follows:
Homopolymers of styrene and its substituted products such as polystyrene, polyP-chlorostyrene, polyvinyltoluene; styrene-P-chlorostyrene copolymers, styrene-propylene copolymers, styrene-vinyltoluene copolymers1.
<Styrene-vinylnaphthalene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, sterene-meccrylic acid Methyl copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-acrylic-amine acrylic copolymer, styrene-aminoacrylic copolymer, styrene-alpha chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer,
Styrene-vinylethyl ether copolymer, styrene-
Styrenic compounds such as vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-imprene copolymer, styrene-acrylonitrile-indene copolymer, styrene-maleic acid copolymer, and styrene-maleic acid ester copolymer Copolymers; polymethyl methacrylate, polymethyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, polyurethane, polyamide, buepoxy resin, polyhinyl!゛Tyral, polyacrylic acid 111. Rosin, modified rosin, terpene resin, phenol resin, aliphatic or alicyclic hydrocarbon resin, aromatic petroleum resin, chlorinated paraffin, paraffin wax, etc. can be used alone or in combination.

In the non-magnetic developer of the present invention, any suitable pigment or dye can be used as a colorant.

For example, there are known dyes and pigments such as carbon black, iron black, phthalocyanine blue, IT, quinacridone, and benzine yellow.

In addition, as charge control agents, amine compounds, quaternary ammonium compounds, organic dyes, especially basic dyes and their salts, benzyldimethyl-hexadecyl ammonium chloride, decyl-trimethylammonium chloride, nigrosine base, nigrosine hydrochloride, 7-lanine γ
Also, crystal violet, metal-containing dyes, salicylic acid metal-containing compounds, etc. may be added.

The structure of the non-magnetic developer described above may be used in a developer produced by a commonly used mixing-pulverization method, or may be used in the wall or core material or both of the microcapsule developer.

Examples are shown below, but the present invention is not restricted thereto in any way.

[Example 1] An example of the present invention will be explained with reference to FIG. In the figure, the same members as in FIG. 1 are given the same reference numerals. In the embodiment apparatus, the photosensitive drum 1 rotates in the direction of arrow a at a circumferential speed of 60 W rotation. 2 is a stainless steel (SUS
304), the surface of which was subjected to amorphous sandblasting using +600 alundum abrasive grains to give a circumferential surface roughness of 08 μm (R−=).

On the other hand, a sintered ferrite type magnet 7c is fixedly disposed inside the rotating sleeve 2, and the N pole of its first magnetic pole is connected to the magnetic blade 6 (7) so that the center O of the sleeve 2 and the tip of the blade are connected. The connecting line is set at an angle of 30 degrees (θ in the figure).The S pole of one of the second magnetic poles is located opposite to the iron piece 10, which is a magnetic member provided on the sleeve entrance side of the container. The magnetic flux density on the sleeve surface of the magnetic pole had a peak value of 650 Gauss in the presence of the iron piece 10, and 400 Gauss when the iron piece 10 was removed.At this time, the positional relationship between the second magnetic pole and the iron piece lO was , the width of the iron piece in the sleeve rotation direction is 0.5 cm, and the distance between the sleeve 2 and the iron piece is 1
, set to OIIi+.

The 7'' magnetic blade 6 was made of iron and the surface thereof was nickel plated to prevent rust.The spacing between the blade 6 and the sleeve 20 surface was set at 200 μm.

The magnetic particles 5 have a particle size of 70 to 100μ, a maximum of 60μ.
emu/g spherical ferrite (manufactured by TDK) 100
1 part by weight of negatively chargeable silica fine powder (R-972, manufactured by Nippon Aerosil Co., Ltd.) was externally added to the part by weight using a Henschel mixer, and 100 g of it was filtered out.

On the other hand, as the non-magnetic developer 4, a polyester resin 10
0 parts, 3 parts of copper phthalocyanine pigment and 5 parts of negative charge control agent (metal alkyl salicylic acid chain) were internally added to form a cyan-colored powder with an average particle size of 12 μm and negatively charged (-1 polarity). 1200 g of the non-magnetic developer and magnetic particles were prepared.Then, after thoroughly mixing the non-magnetic developer and magnetic particles, they were placed in the container 3.The mixture of the non-magnetic developer and the magnetic particles in the container 3 was as follows:
In particular, it was possible to observe the circulation movement of the magnetic particles as they were transported by the sleeve under the magnetic field, even when the amount of developer was low.

In the developing device having the above configuration, as the IJ-b rotated, an auxiliary layer of only non-magnetic developer having a thickness of about 100 μm was formed on the surface of the sleeve 2. When the charging potential of this developer layer was measured by the blow-off method, it was found that -
It was confirmed that it was uniformly charged at a potential of 6 μc/g.

On the surface of the photosensitive drum 1 facing the sleeve 2, a charge pattern of +600 V in the dark part and 1150 V in the bright part was formed as an electrostatic latent image, and the distance from the sleeve surface was set to 300 μm. Then, a frequency of 80 Q Hz was applied to the sleeve by power source E.

Peak-to-peak value is 1.4 kv, center value is +300
A voltage of V was applied. However, uneven development f ghost image,
Furthermore, it was possible to obtain a high quality developed image with no fog.

Furthermore, regarding the mixture in container 3, only the non-magnetic developer was consumed for development, with almost no magnetic particles being consumed. Further, the developing function remained unchanged until almost all of the developer was consumed. After the developer was consumed, the developing device was removed from the main body and the lower part of the sleeve 2 was examined, and not only were there no magnetic particles, but almost no developer leaked there.

By the way, in the present invention, the number of magnetic poles provided inside the sleeve does not need to be limited to two, the first and second magnetic poles. The object of the magnetic brush formed by the second magnetic pole is not limited to the magnetic member, and may be the wall of the container. In this case, the presence of the magnetic member is no longer necessary, and the shape of the south pole shown by the chain line in FIG. 2 is taken. Furthermore, when a magnetic member is used for the second magnetic pole, if the container is a magnetic material, the magnetic blade 6 and the iron piece 10 shown in FIG. 2 can be constructed from the wall of the container. A portion of the container can be replaced by an axially convex portion of the sleeve.

By the way, although all the examples are shown when an S pole is used as the second magnetic pole, it may of course be an N pole. Further, as for the regulating means, although a blade plate made of a magnetic material is illustrated, a wall or a plate-like member made of a non-magnetic material such as synthetic resin, aluminum, brass, stainless steel, etc. may also be used. However, when using a non-magnetic material, unlike when using a magnetic material, a magnetic field is not generated between it and the first magnetic pole, so the type of brush created by the magnetic particles inside the container is different; This makes it easier for water to leak downstream. However, this point can also be solved by setting the gap between the sleeve and the non-magnetic regulating means to about half or less of the magnetic particle diameter. Furthermore, in addition to attaching the regulating member separately from the container, a part of the container may be used as a regulating plate. Furthermore, the bias during development is not limited to an alternating voltage, but it is also effective to apply a direct current voltage.

[Example 2] Fine silica powder Aerosil 200 (manufactured by Nippon Aerosil Co., Ltd.) was placed in a closed-type Henschel mixer heated to 70°C, and the amount of silane coupling agent was 10% by weight relative to the silica. γ− diluted with alcohol
The mixture was stirred at high speed while the aminepropyltriethoxysilane was added dropwise. The obtained fine powder was dried at 120° C., then put into the Henschel mixer again, and while stirring, dimethyldichlorosilane was sprayed to the silica at a concentration of 10% by weight. The mixture was stirred at high speed for 2 hours at room temperature, further stirred at 80° C. for 24 hours, and then the mixer was opened to atmospheric pressure. This mixture was further mixed at low speed at atmospheric pressure for 6 hours.
It was dried at 0° C. for 5 hours to obtain positively chargeable silica fine powder. Magnetic particles 1 using 1 part by weight of silica fine powder in Example 1
00 parts by weight using a Henschel mixer, i o o
I put out g'i.

On the other hand, as the non-magnetic developer 4, 100 parts of styrene-acrylic resin, 5 parts of rhodamine pigment, 2 parts of positive charge control agent and glocine) were added internally, and the average particle size was 10 μm.
150 g of positively chargeable powder was prepared.

Also, the dark area -600V as an electrostatic latent image on the surface of the photoreceptor drum.
, bright area -200V17) forming a charge pattern, for the sleeve frequency 100011=, peak-to-peak value 1.
The same procedure as in Example 1 was carried out except that a voltage of 3kV and a center value of 1300μ was applied, and there was a voltage of +8μ on the sleeve.
The non-magnetic developer charged at c/g was uniformly coated, and a good image was obtained.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a developing device for explaining the principle of the present invention. FIG. 2 is a sectional view of a developing device used in an embodiment of the present invention. In the figure, 2 is a sleeve which is a developer holding member, 3 is a container, 4 is a non-magnetic developer, 5 is a magnetic particle, 6 is a magnetic blade which is a regulating member, 7 is a magnet, and 10 is an iron piece which is a magnetic member. show.

Claims (1)

[Scope of Claims] A container for storing non-magnetic developer and magnetic particles, a developer holding member for rotationally conveying the non-magnetic developer to a latent image carrier, and a supply outlet for the non-magnetic developer of the container. a regulating member disposed on the side with a gap formed on the surface of the holding member; and a regulating member disposed on the opposite side of the regulating member across the holding member and located on the developer outlet side of the container. and a magnet having at least one magnetic pole forming a magnetic brush made of magnetic particles on the upstream side of the holding member, and a coating method in which a thin layer of non-magnetic developer is formed on the holding member, the magnet having the same polarity as the non-magnetic developer. A coating method characterized by using magnetic particles carrying on the surface fine silica powder having triboelectric charging properties.