JPH0231384B2 - GENZOHOHO - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of developing, particularly a method of developing a potential image.

Conventionally, various types of electrophotographic processes for forming potential images are known. For example, the most common electrophotographic process involves charging and imagewise exposure to form a potential image.

A potential image is generally formed by charging the surface of a photoreceptor by corona discharge, and then selectively eliminating charges in exposed areas by imagewise exposure.
This potential image is developed with toner charged with a polarity opposite to that of the potential image, and is transferred onto transfer paper.

Other electrophotographic processes have also been proposed that allow for easy miniaturization of the apparatus. Representative examples include JP-A-48-68238, JP-A-51-150342, JP-A-53-1027, JP-A-54-61534, and JP-A-54-61537. Disclosed in official gazettes, etc. These methods can form potential images that can be developed with charged toner without requiring corona charging. That is, by applying a voltage to a photoconductive layer provided with electrodes to perform image exposure, a difference in voltage distribution is created between the exposed area and the unexposed area with respect to the applied voltage, thereby increasing the potential. It forms an image.

Conventional methods for developing the potential image formed in this manner include the cascade method, magnetic brush method, fur brush method when the developer is a powder, and the toner dispersed in a liquid when the developer is a wet type. A liquid development method is used in which the electrophoretic material migrates (by the action of the electric force of the potential image of the photoreceptor) and is visualized by adhering to the surface of the photoreceptor.

However, in order to obtain high-quality images using these conventional methods, a potential contrast of at least 200 V or more, preferably 400 V or more is generally required as a potential image. If the latent image potential is below the above-mentioned latent image potential, the noise level will be high in the conventional method, and the image quality will become foggy or the image will become faint.
I can't get a good quality image.

Therefore, the main object of the present invention is to provide a developing method that improves the above-mentioned drawbacks.

The developing method of the present invention includes a photoconductive layer having a light-transmitting electrode and a light-shielding electrode on a light-transmitting support,
An image holding member having an isolated conductor on the photoconductive layer and a protective layer on the photoconductive layer and the isolated conductor is supported while a voltage is applied between a light-transmitting electrode and a light-shielding electrode. By performing image exposure from the body side, a potential latent image is formed on the surface of the image holding member, and a magnet and a magnetic body are integrally provided, and a resistance is created at the tip of the magnetic body that is magnetized by the magnet. 10 ⁶
A developing device holding magnetic toner with a low resistance of Ωcm or less is brought close to the surface of the image holding member, and the developing device and the image holding member are relatively moved to perform development. be.

That is, the present invention is a developing method that allows a high-quality image to be obtained even when the latent image potential is as low as 100 V or less.

One typical aspect of the developing method according to the present invention is the first
As shown in the figure.

A potential image is formed on the image holding member 1. The structure of the image holding member and the method of forming a potential image are shown in FIGS. 2 to 5. First, the structure of the image holding member 1 is as shown in FIG.
and a protective layer 8.
The light-transmitting electrode 5 and the light-shielding electrode 6 are patterned electrodes formed on the support 2, and have a comb-like shape as shown in FIG.

The isolated conductor 4 is a discontinuous island-shaped conductor, and is an important conductor that becomes a pixel of an image to be formed. As shown in the plan view of FIG. 4, the isolated conductors are formed in a mutually isolated state.

The support 2 is transparent and made of glass, resin, or the like. The light-transmitting electrode and the light-shielding electrode can be formed by various methods, but the typical manufacturing method is vapor deposition and chemical etching using photoresist. In this method, a material for forming a transparent electrode, such as In ₂ O ₃ or SnO ₂ , is first vapor-deposited on the surface of the support, and then a comb-shaped masking pattern is formed using photoresist. Then, after selectively etching away the layer such as In ₂ O ₃ using a predetermined etching solution such as acid or alkali, the masking pattern of the photoresist is removed to form a transparent electrode. Further, a light-shielding electrode is also formed on the support in exactly the same manner. Light-shielding electrode forming materials include Al, Ir, Ag,
Pb, Zn, Ni, Au, Cr, Mo, Nb, Ta, Ti, Pt
Various metals such as are used.

These metals are formed into layers by vapor deposition, electron beam deposition, sputtering deposition, and the like. As the photoresist, any conventionally commonly used materials can be used. For example, as a commercially available product,
Product name: KPR (Kodak photo Resist, manufactured by Kodak...developer; methylene chloride, trichlene, etc.), product name: KMER (Kodak Metal Etch)
Resist, made by Kodatsuku...developer; xylene, trichlene, etc.), product name: TPR (manufactured by Tokyo Ohka...developer; xylene, trichlene, etc.), product name: Shippray AZ1300 (manufactured by shippray...developer; alkaline aqueous solution) , Product name: KTFR (Kodak Thin
Film Resist, manufactured by Kodatsuku...developer; xylene, trichlene, etc.), product name: FNRR (Fuji Pharmaceutical Co., Ltd....developer; chlorocene), product name;
FPER (Fuji Photo Etching Resist, manufactured by Fuji Photo Film... developer; Triclean), product name;
TESH DOOL (manufactured by Okamoto Chemical Industry...developer; water),
and product name; Fuji Resist No. 7 (manufactured by Fuji Pharmaceutical Co., Ltd.; developer; water). After using the mask, remove it with Triclean, methylene chloride, product name: AZ Remover (manufactured by Shitsupray),
Sulfuric acid etc. are used. The light-transmitting electrode and the light-shielding electrode are formed by depositing the electrode forming material onto the support through a mask having comb-shaped openings, and then
It can also be formed by removing the mask. The thickness of the transparent electrode is usually about 500 Å to 6000 Å.
Further, the thickness of the light-shielding electrode is usually about 500 Å to 2 μ.

The photoconductive layer includes S, Se, Pbo, and S, Se, Te,
It is formed by vacuum deposition of an inorganic photoconductive material such as an alloy or intermetallic compound containing As, Sb, etc. In addition, when using the sputtering method, ZnO, CdS, CdSe,
A photoconductive layer can also be formed by depositing a high melting point photoconductive material such as TiO ₂ on the support. In addition, when forming a photoconductive layer by coating, organic photoconductive materials such as polyvinicarbazole, anthracene, phthalocyanine, dye-sensitized or Lewis acid-sensitized products of these materials, and mixtures thereof with insulating binders can be used. can be used. Also ZnO, CdS, TiO ₂ ,
Mixtures of inorganic photoconductors such as PbO with insulating binders are also suitable. Note that various resins are used as the insulating binder. The thickness of the photoconductive layer is
Although it depends on the type and characteristics of the photoconductive substance used, it is generally 1 to 100 microns, particularly about 1 to 50 microns.

An isolated conductor is a discontinuous island-like conductor, and is an important conductor that becomes a pixel of an image to be formed. Although the shape of the isolated conductor is square in FIG. 4, it may have another shape such as a circle. The thickness of the isolated conductor is determined depending on whether it can be formed in exactly the same way as the transparent electrode or the light-shielding electrode, but it is usually desirable to have a thickness of 1 to 100 μm.

An isolated conductor 4 is formed on the a-Si layer. The isolated conductor is formed in exactly the same way as a light-transmitting electrode or a light-shielding electrode. The thickness of the isolated conductor is usually set to 500 Å to 2 μ.

The mechanism by which a potential image is formed using the image holding member shown in FIG. 2 will be explained with reference to FIG.

FIG. 5 is an equivalent circuit of the image holding member shown in FIG. 2.

A power supply 7 is connected between the light-transmitting electrode and the light-shielding electrode, and in FIG. 5, the voltage applied by the power supply 7 is
Displayed as Va.

R ₁ is the resistance between the light-shielding electrode 6 and the isolated conductor 4 , and R ₂ is the resistance between the isolated conductor 4 and the light-transmitting electrode 5 . Potential at isolated conductor 4
V ₀ is the voltage applied between the transparent electrode 5 and the isolated conductor 4, and is expressed by the following formula (1): V ₀ =R ₂ /R ₁ +R ₂ Va. By applying image light from the support side while voltage Va is applied, a difference is generated in the potential of the isolated electrode in the exposed area and the non-exposed area.

Regarding the exposed portion, since exposure light does not reach the photoconductive layer in the portion shielded by the light-shielding electrode, the resistance R ₁ between the light-shielding electrode and the isolated conductor remains unchanged. Furthermore, since the exposure light reaches the a-Si layer in the transparent electrode portion, the resistance R ₂ between the isolated conductor and the transparent electrode decreases. If the equation (1) is modified as V ₀ =1/R ₁ /R ₂ +1Va . . . equation (2), it is directly shown that if the resistance R ₂ decreases, the potential of the isolated conductor decreases. On the other hand, in the non-exposed area, neither R ₁ nor R ₂ changes, so the potential of the isolated conductor does not decrease. Therefore, the potential in the exposed area is low and the potential in the non-exposed area is high, forming a potential image. If the polarity of the applied voltage is reversed, an inverted potential image is formed.

As shown in FIG.
1. This developing operation is performed by moving the image holding member and the developing device relatively, that is, by moving the image holding member or the developing device, or both, in opposite directions.

The resistor 12 forms a control circuit for applying a desired voltage to the magnetic body 10 to prevent fogging. Usually, it is best to apply a potential corresponding to the potential of the non-image portion of the potential image formed on the image holding member to the magnetic material by a control circuit. Note that such a control circuit may be omitted.

The toner used for development is magnetic and has low resistance. Usually, a magnetic toner with a low resistance of 10 ⁶ Ωcm, particularly 10 ⁵ Ωcm or less is suitable. Such toners generally consist of a binding material, magnetic powder and additives.

Examples of the binder resin include monopolymers of styrene and its substituted products such as polystyrene, polyP-chlorostyrene, and polyvinyltoluene;
P-chlorostyrene copolymer, styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene - Octyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer,
Styrene-a chloromethacrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl ethyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer polymer, styrene-isobrene copolymer, styrene-acrylonitrile-indene copolymer,
Styrenic copolymers such as styrene-maleic acid copolymer, styrene-maleic acid ester copolymer, polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate,
polyethylene, polypropylene, polyester,
Polyurethane, polyamide, epoxy resin, polyvinyl butyral, polyamide, polyacrylic acid resin, rosin, modified rosin, terpene resin, phenolic resin, aliphatic or alicyclic hydrocarbon resin,
Aromatic petroleum resins, chlorinated paraffin, paraffin wax, etc. can be used alone or in combination.

Magnetic powders include ferromagnetic elements and alloys and compounds containing them, such as magnetite,
There are substances conventionally known as magnetic materials, such as alloys and compounds of iron such as hematite and ferrite, cobalt, nickel, and manganese, and other ferromagnetic alloys.

Further, as additives, carbon black, ultramarine blue, nigrosine, metal complex dyes, colloidal silica, etc. can be used for the purpose of coloring charge control, prevention of aggregation, and the like.

It is better to have a narrower distance between the surface of the image holding member and the magnetic material, and generally 0.1 mm to 2 mm is suitable. Furthermore, the toner attached to the magnetic material is kept in constant contact with the surface of the image holding member. The toner image thus obtained is clear with little fogging even if the potential image is at a low potential. Regarding the formation of clear images, the amount of toner existing between the tip of the magnetic material and the surface of the image holding member is small, and the toner itself has low resistance, so even if the potential of the potential image is low, the influence of this potential is not affected. It is thought that this is sufficiently transmitted to the toner and the toner is efficiently attached to the potential image. In terms of development, the toner adhering to the magnetic material is separated by magnetic force due to the electrostatic force of the potential image.

Example 1 In ₂ O ₃ was deposited on a glass plate using an electron beam.
was deposited to a thickness of 2000 Å. Next, a light-transmitting electrode (a=20μ, b=110μ) as shown in FIG.
was formed. Next, by depositing Al through a metal mask, the
1μ thick light-shielding electrode (C=30μ, d=50μ, e=
80μ) was formed. Next, an a-Si (amorphous silicon) layer was formed on this.

To form the a-Si layer, a glass plate is placed in a bell jar filled with 10 ^-2 mmHg gas (SiH ₄ /Ar = 1/9), and two sheets are placed at 3 cm intervals on both sides of the glass plate. Flat plate electrodes were arranged, and a high frequency wave of 13.56M cycles was applied to both electrodes to generate plasma discharge. The gas (SiH ₄ /Ar) during discharge is
The flow rate is 1CC/sec, and the temperature of the glass plate is 150℃.
I kept it. When the glass plate was taken out from the bell gear after 5 hours from the start of discharge, a 10μ thick a-Si layer was formed, and the dark resistance of this a-Si layer was 5×10 ⁷
Ωcm, 2×10 ³ Ωcm by 10lux visible light irradiation
It has characteristics that change.

Next, an isolated conductor as shown in FIG. 4 was formed. That is, through a metal mask on the a-Si layer.
An isolated electrode (f=g=
100μ, h=30μ). Further on top of this
An image holding member as shown in FIG. 1 was manufactured by forming a 3000 Å thick polyparaxylylene layer as a protective layer.

This image holding member was set as shown in FIG. Under the magnet 9 is a wire with a width of 1 mm, a height of 2 cm, and a length of 10 cm.
A developing device integrally provided with a plate-shaped magnetic material was disposed close to the surface of the image holding member. The distance between the tip of the magnetic material and the surface of the image holding member was set to 0.5 mm.
The toner contains magnetite and carbon black in a weight ratio of 7:3. A material with a particle size of 7 μ or less and a resistance of 10 ⁴ Ωcm or less was used. As shown in FIG. 1, the potential image was formed by performing image exposure from the support side while applying a DC voltage of 50 V between the light-transmitting electrode and the light-shielding electrode. The potential image is 30V in the image area (dark area), and 30V in the non-image area (bright area).
It was 5V. Adjust resistor 12 to make it magnetic
Develop this potential image with a voltage of 5V applied,
A clear toner image was obtained. At this time, the image holding member is
It was moved at a speed of cm/sec.

In this example, when the voltage applied to the magnetic material is set to 0V, some fogging occurs on the toner image.
On the other hand, when I set it to 10V, it became weaker.

Furthermore, when the distance between the magnetic material and the image holding member was set to 3 mm, toner was sufficiently interposed therebetween, and the moving speed of the image holding member was set to 5 cm per second, the entire toner image became somewhat faint. Conversely, when the interval was narrowed to about 0.05 mm, the toner image became slightly fainter.

[Brief explanation of drawings]

FIG. 1 shows one embodiment of the developing method according to the present invention. Figures 2, 3 and 4 are respectively
The structure of the image holding member shown in the figure is shown, and FIG. 2 is a sectional view, FIG. 3 is a plan view of a light-transmitting electrode and a light-shielding electrode, and FIG. 4 is a plan view of an isolated conductor. FIG. 5 shows an equivalent circuit of the image holding member shown in FIG. 9 and 14...magnet, 10 and 15...magnetic material, 11 and 16...toner.

Claims (1)

[Scope of Claims] 1. A photoconductive layer having a light-transmitting electrode and a light-shielding electrode on a light-transmitting support, an isolated conductor on the photoconductive layer, and the photoconductive layer and A potential latent image is formed on the surface of the image holding member by performing image exposure from the support side while a voltage is applied between the light-transmitting electrode and the light-shielding electrode of the image holding member having a protective layer on the isolated conductor. A developing device is provided in which a magnet and a magnetic material are integrated, and a developing device holding a low-resistance magnetic toner with a resistance of 10 ⁶ Ωcm or less is placed at the tip of the magnetic material, which is magnetized by the magnet. A developing method characterized by developing by relatively moving the developing device and the image holding member in a state in which they are brought close to the surface of the holding member. 2. The developing method according to claim 1, wherein the magnetic material is plate-shaped.