JPS641012B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an image forming method, and particularly to an image forming method that utilizes a difference in distributed voltage due to a change in the resistance of a photoconductive layer.

Conventionally, various image forming methods are known. When it comes to electrophotographic image formation, the most common electrophotographic process involves charging and imagewise exposure to form an electrostatic image.

An electrostatic image is generally formed by charging the surface of a photoreceptor by corona discharge, and then selectively dissipating the charges in the exposed areas by imagewise exposure.
This electrostatic image is developed with toner charged with a polarity opposite to that of the electrostatic image, and is transferred onto transfer paper. It has been pointed out that this type of electrophotographic process requires wires and shield cases to perform corona charging, as well as high voltage to generate corona discharge, making it difficult to make the equipment more compact. .

On the other hand, image forming methods have also been proposed that allow the apparatus to be made more compact. Representative examples include JP-A No. 48-68238 and JP-A-Sho.
It is disclosed in JP-A-51-150342, JP-A-53-1027, JP-A-54-61534, and JP-A-54-61537. 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.

However, in an image forming process using such a photoreceptor that does not require corona charging, a visible image is formed by directly applying the developer to a collection surface of minute isolated conductors on the surface of the photoreceptor. The collective surface of the isolated conductors was easily damaged or contaminated, making it difficult to use the photoreceptor for a long time.

Therefore, the present invention is free from such drawbacks, that is,
The main objective is to provide an image forming method that does not cause damage or staining of the photoreceptor.

The image forming method according to the present invention has a photoconductive layer provided with a transparent electrode and an opaque electrode on a transparent support, and isolated conductors forming pixels are provided on the photoconductive layer, A transparent electrode and an opaque electrode are arranged corresponding to the isolated conductor, and a voltage can be applied between the transparent electrode and the opaque electrode. Image exposure is performed by applying a voltage to both electrodes of the photoreceptor. A difference in distributed voltage is created between the exposed area and the required exposure area of the photoreceptor, and the charge of the potential image due to the difference in potential of the isolated conductor that occurs in response to the difference in the distributed voltage is transferred to the image receiving member. It is characterized by this.

This is because the image forming method according to the present invention does not directly develop the potential image formed on the isolated conductor of the photoreceptor, but rather transfers the charges of the potential image to the image receiving member and develops the image receiving member. , the photoreceptor is not damaged or stained by the developer, and the photoreceptor can be used for a long time. As the photoreceptor used in the image forming method of the present invention, those having the conventional configurations described above may be used as appropriate, but a linear photoreceptor is particularly effective. That is, the photoconductive layer used in the photoreceptor that forms a potential image may be formed of the same material as the photoconductive layer forming material of the conventional photoreceptor;
Since the resolving power of the image formed depends on the density of the electrodes and isolated conductors on the photoreceptor, generally a photoreceptor having an area corresponding to the area of the image to be copied and having finely patterned electrodes and isolated conductors is used. This is because, although it is not easy to manufacture, a linear photoreceptor with a small width is very easy to manufacture. The photoreceptor shown in FIG. 1 is a cross-sectional view of one typical row of such a linear photoreceptor.

FIG. 2 is an exploded view for explaining the structure of the photoreceptor shown in FIG. 1. FIG.

The photoreceptor is composed of a transparent support 1, a transparent electrode 4, an opaque electrode 3, a photoconductive layer 3, and an isolated conductor 5. The three-dimensional laminated structure of the photoreceptor support 1, photoconductive layer 2, transparent electrode 4 and opaque electrode 3 is as shown in FIG. 2, and both electrodes of the photoreceptor are in the form of stripes. As shown in FIG. 2, the isolated conductors 5 of the photoreceptor are formed in a mutually isolated state.

The support 1 is transparent and made of glass, resin, or the like. Transparent electrodes and opaque electrodes can be formed by various methods, but typical methods include 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 striped 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 can be removed to form a transparent electrode.
Further, an opaque electrode is also formed on the support in exactly the same manner. Examples of opaque electrode forming materials include Al,
Ag, Pb, Zn, Ni, Au, Cr, Mo, Ir, Nb,
Various metals such as Ta, U, Ti, and Pt 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 commercially available products, product name: KPR (Kodak Photo Resit, manufactured by Kodatsu... developer: methylene chloride, trichlene, etc.), product name: KMER (Kopak Metal
Etch Resit, manufactured by Kodatsuku...Developer: xylene,
Triclean, etc.), Product name: TPR (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...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…Developer: water)
and so on. To remove the mask after use, use triclene, methylene chloride (trade name: AZ Remover (manufactured by Shippray), sulfuric acid, etc.). The transparent electrode and the opaque electrode can also be formed by depositing an electrode forming material onto the support through a mask having comb-shaped openings, and then removing the mask. The thickness of the transparent electrode is usually
The thickness of the opaque electrode is approximately 500 Å to 6000 Å.
It is usually about 500 Å to 2 μ.

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

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. 2, it may have another shape such as a circle. The formation of isolated conductors can be done in exactly the same way as for transparent or opaque electrodes.

Next, typical modes of forming an image using the photoreceptor shown in FIG. 1 are shown in FIGS. 3 to 5.

In FIG. 3, an original image 7 is irradiated onto a photoreceptor 6 through a lens 9 to perform image exposure. 8 is a light source, and the original image moves in the direction of arrow 20.
A voltage is applied to the photoreceptor in parallel with image exposure,
A potential image is formed. The charges of this potential image are transferred to the dielectric drum 11, which is an image receiving member. The dielectric drum 11 rotates in the direction of the arrow 10 and the developing device 13
The transferred charge image is developed. After development, this developed image is transferred to a transfer paper 14 as a transfer material by a transfer roller 15 and further fixed by a fixing roller 16. Transfer paper 14 is indicated by arrow 1
Move in the direction of 7. The dielectric drum 11 is then cleaned by a cleaning blade 12. The vicinity of the photoreceptor 6 is shown in FIG. That is, the voltage Va applied to the photoreceptor is applied to the transparent electrode 4 and the opaque electrode 3. Then, by image exposure, a difference is created in the voltage distribution between the transparent electrode and the isolated conductor and between the isolated conductor and the opaque electrode between areas where light passes through the transparent electrode and areas where light does not pass through the transparent electrode, A potential image is formed by the potential change of the isolated conductor that occurs in response to the difference in the distributed voltages.
This will be specifically explained using the equivalent circuit of the photoreceptor 6 shown in FIG.

R ₁ is the resistance between the opaque electrode and the isolated conductor, and R ₂ is the resistance between the isolated conductor and the transparent electrode. The potential Vo in the isolated conductor is a distributed voltage between the transparent electrode and the isolated conductor, and is expressed by the formula (1): Vo=R ₂ /R ₁ +R ₂ Va. By performing imagewise exposure from the support side with voltage Va applied, a difference is generated in the potential of the isolated conductor between the exposed area and the non-exposed area. Regarding the exposed area, since the exposure light does not reach the photoconductive layer in the area shielded by the opaque electrode, the resistance R ₁ between the opaque electrode and the isolated electrode remains unchanged. In addition, since the exposure light reaches the photoconductive layer in the transparent electrode part, the resistance R ₂ between the isolated conductor and the transparent electrode decreases using equation (1) as Vo=1/R ₁ /R ₂ +1Va... ...If we transform 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.

The dielectric drum 12 is constructed by forming a dielectric layer 18 on a conductive drum 19. The conductive drum is made of any material such as Al or stainless steel. The dielectric layer is formed from any dielectric material such as resin film, glass, or paper. The conductive drum is a counter electrode to the isolated conductor, and a bias voltage is applied to this counter electrode, if necessary, for transferring the charge of the potential image.

Furthermore, if the dielectric layer can be used as a transfer sheet, such as a resin film or paper, the image developed thereon can be directly fixed to form the final image.

In the present invention, transparent and opaque mean transparent to light used for image exposure and opaque, and are not limited to visually transparent or opaque.

Example In ₂ O ₃ was evaporated to a thickness of 2000 Å on a glass plate by electron beam evaporation through a metal mask.
A transparent electrode (a=40μ) with a pattern as shown in the figure was formed.

Next, Cr was deposited to a thickness of 6000 Å through a metal mask to form an opaque electrode (b=20μ, C=80μ) with a pattern as shown in FIG. Next, amorphous Se was vacuum-deposited to a thickness of 20 μm over the entire surface as a photoconductive layer. Next, Au was evaporated to a thickness of 3000 Å on the amorphous Se layer through a metal mask, forming an isolated conductor in the pattern shown in Figure 2 (d = 180 μ, e = 180 μ,
f=20μ) was formed. A photoreceptor was manufactured in this manner.

In addition, Al was vapor-deposited on a 25μ thick polyethylene terephthalate film, and this was vapor-deposited on the Al drum surface.
A dielectric drum was manufactured by adhering the Al layer as an adhesive surface.

Next, the transparent electrode side of the photoreceptor is grounded and a +100V DC voltage is applied between it and the opaque electrode, image exposure is performed from the glass plate side, and the potential image is transferred by contacting it with a dielectric drum whose back side is grounded. When the image was developed with negatively charged toner and transferred to transfer paper, a clear image with a resolution of 25 lines/mm was obtained.

At this time, the contrast between the exposed area and the non-exposed area was 65 V on the surface of the photoreceptor before the potential image was transferred, and 60 V on the surface of the dielectric drum after the potential image was transferred. Further, even after repeating this image forming process 10,000 times, no deterioration in image quality was observed and the photoreceptor did not deteriorate.

[Brief explanation of the drawing]

FIG. 1 shows one embodiment of the photoreceptor used in the present invention. FIG. 2 is an exploded view of the photoreceptor shown in FIG. 1. FIG. 3 shows one embodiment of the invention. FIG. 4 is a partially enlarged view of FIG. 3. FIG. 5 is an equivalent circuit diagram of the photoreceptor shown in FIG. 3. DESCRIPTION OF SYMBOLS 1... Support, 2... Photoconductive layer, 3... Opaque electrode, 4... Transparent electrode, 5... Isolated conductor, 6...
...Photoreceptor, 11...Dielectric drum.

Claims (1)

[Scope of Claims] 1. A photoconductive layer having a transparent electrode and an opaque electrode provided on a transparent support, isolated conductors forming pixels are provided on the photoconductive layer, and a transparent An electrode and an opaque electrode are arranged corresponding to the isolated conductor, and a voltage can be applied between the transparent electrode and the opaque electrode.By applying a voltage to both electrodes of the photoreceptor and performing image exposure. Generating a difference in distributed voltage between exposed and non-exposed areas of a photoreceptor, and transferring charges of a potential image to an image receiving member due to a difference in potential of an isolated conductor that occurs in response to the difference in distributed voltage. An image forming method characterized by: 2. The image forming method according to claim 1, wherein the charge image transferred to the image receiving member is developed. 3. The image forming method according to claim 1, wherein the photoreceptor is linear.