JPS599667A - Method for forming electrostatic latent image on electrophotographic receptor and on its photoreceptor - Google Patents

Abstract

PURPOSE:To obtain the entitled photoreceptor through which the color of an original image can be seen in high fidelity during formation of an image, by laminating a transparent conductive layer, a transparent organic photoconductive layer, and a specified white layer on a transparent plastic film. CONSTITUTION:A transparent conductive layer (B) having 5-5X10<9>OMEGA/? surface resistance, and (C) a 3-100mum thick transparent org. photoconductive layer composed of an org. photoconductor, a polymer binder, and a sensitizing agent are laminated on a 10-500mum thick biaxially stretched transparent plastic film (A) so as to control a transmittance of the total light at 550nm wavelength to >=50%. On this layer (C) a white layer (D) consisting of a polymer binder, and a white pigment having <=20mum average particle diameter, and having 3-50mum thickness and >=70% Hunter whiteness is formed. An electrostatic latent image is formed on the layer D of an electrophotographic receptor by charging the layer D and exposing the layer C to light from the layer A through the layer B.

Description

[Detailed description of the invention] The present invention relates to an electrophotographic photoreceptor.

More specifically, the present invention relates to an electrophotographic photoreceptor in which one image forming surface is white.

Conventionally, electrophotographic photoreceptors include Se-Te,
ZnO.

Inorganic photoconductors such as CdS, organic photoconductors such as polyvinylcarbazole (PVK), pyrazoline, oxadiazole, and hydrazone, and composites thereof are known. However, these electrophotographic photoreceptors are usually colored by themselves or with a sensitizer. Therefore, when electrophotographic photoreceptors with high surface whiteness are required, efforts have been made to make them appear white at first glance by adding dyes that are complementary colors to these colors. However, with this method, sufficient brightness could not be obtained, resulting in surfaces that were close to gray or slightly colored.

For this reason, when forming a toner image on an electrophotographic photoreceptor and fixing it as is, not only a black and white image but especially when forming a color image, the coloring faithfully reproduces the colors of the original image. The disadvantage was that it had an adverse effect on the

The object of the present invention is to eliminate the above-mentioned drawbacks and to provide a single image.

Particularly, it is an object of the present invention to provide an electrophotographic photoreceptor in which the colors of the original image can be faithfully seen when forming a color image, and a method for forming an electrostatic latent image on the photoreceptor.

The present invention has the following configuration to achieve the above object.

That is, a transparent plastic film (A), a transparent conductive layer (B), and a transparent organic photoconductive layer (C).

... a white layer (D) having an intermediate whiteness of 70 or more.

(A) / (B) /' (C) / (D) When forming an image on the electrophotographic photoreceptor and the photoreceptor, a charge is applied to the surface of (A) and (D )
This method is characterized by a method of forming an electrostatic latent image on the surface of the photoreceptor (A) by exposing it to light from the side of the photoreceptor (A).

The transparent plastic film in the present invention (hereinafter referred to as (
A)-1 may be any transparent plastic film. Preferred is polyethylene terephthalate.

Polybutylene terephthalate, polyethylene-2゜6-
Polyesters, polyolefins such as polyethylene, polypropylene, etc., such as naphthalene dicarboxylate
Polyamides such as so-called nylon-6 and nylon/-12, polyimides having a five-membered ring imide condensation in the polymer main chain, cellulose derivatives such as cellulose esters, polystyrene, polycarbonate, and acrylic acid ester copolymers.

Methacrylic acid ester copolymer, polyvinyl chloride.

Examples include hollyether, holJ ester ether, and polyester amide, and may also be a blend or copolymer of two or more of these.

These plastic films are stretched.

Particularly desirable are those that have been subjected to biaxial stretching.

The thickness of (A) varies depending on the application, but from 10 μm to 5 μm.
00 μm, more preferably 10 μm to 200 μm.

The transparent conductive layer (hereinafter abbreviated as (B)) is transparent and has a surface resistance value of 5Ω/hole to 5×10′Ω/hole. Preferred compositions for forming (B) include Az, Cr, Cd, Ti, Fe, Cu,
Engineering n, Ni.

Pd, Pt, 'Rh, Ag, Au, Su,
Metals such as W and Zr and their alloys, metal oxides such as indium oxide, indium oxide/tin oxide, indium oxide/cadmium oxide, and tin oxide, metal compounds such as copper iodide, quaternary ammonium, sulfonates, Examples include polymer electrolytes such as polyalcohols. These may be used alone or in combination of two or more. Such a transparent conductive layer may be formed by plating, vacuum deposition, chemical vapor deposition, sputtering, coating, or the like.

In the present invention, in the combination of (A) and (B),
The transparency is preferably 50 cm or more in terms of total light transmittance (550 nm).

The transparent organic photoconductive layer (hereinafter abbreviated as (C)) is
The layer is mainly composed of an organic photoconductor and a polymeric binder, and an appropriate sensitizer can be added if necessary. The organic photoconductor and polymeric binder may be used as long as the mixture is transparent.

Generally known ones can be used. Typical examples include polyvinylcarbazole and its derivatives, pyrazoline derivatives, hydrazone derivatives, acylhydrazone derivatives, imidasilone derivatives, imidazothion derivatives, benzimidazole derivatives,
Examples include, but are not limited to, oxazole derivatives, benzupoxazole derivatives, benzothiazole derivatives, oxadiazole derivatives, and the like.

Examples of polymer binders include polyester, polyether,
Polycarbonate, polyamide, polyurethane, acrylic ester copolymer, methacrylic ester copolymer, polystyrene-butadiene copolymer, polyvinyl acetal, chlorinated polyolefin, ethylene-vinyl acetate copolymer, polyvinyl acetate, polyvinyl chloride, Thermoplastic resins such as vinyl acetate-vinyl chloride copolymer, vinyl acetate-vinyl chloride-maleic anhydride copolymer, polyurethane, cellulose derivatives, silicone resin, alkyd resin, ketone resin, xylene resin, epoxy resin, unsaturated polyester , thermosetting resins such as polyimide, and further resins in which a curing agent is added to thermoplastic resins having functional groups such as hydroxyl groups, carboxyl groups, and amine groups. Any of these may be used alone or in a mixed system of two or more.

The sensitizer is usually appropriately selected from those known as chemical sensitizers 1 and dye sensitizers.

As the chemical sensitizer, those generally known as electron-withdrawing substances are preferably used. For example, tetraanoethylene, tetracyanoquinodimethane, l-!
j Nitrofluorenone, Bromanil.

Examples include chloranil, benzoquinone, naphthoquinone, anthraquinone, anthraquinone derivatives, and Lewis acids. Dye sensitizers include triphenylmethane dyes, rhodamines, and xanthene dyes.

Acridine dyes, quinoline dyes, ketone dyes, cyanine dyes, allylmethane dyes, polymethine dyes.

Azo dyes, azomethine dyes, carbonyl dyes, phthalocyanino dyes, biryllium dyes, and the like are preferably used.

The weight ratio of organic photoconductor/polymer binder/sensitizer is 110.
．． It is preferable that it is 2-6010-01.

The thickness of (C) is preferably 3 μm to 100 μm, more preferably 5 μm to 20 μm.

In the present invention, in the combination of (A) / (B) / (C), transparency is the total light transmittance (550 nm)
It is preferable that it is 50% or more.

The white layer (hereinafter abbreviated as (D)) has an interwhiteness of 70 or more, and is made by dispersing a white pigment in a polymeric binder.

As the polymer binder, those mentioned above can be used.

As the white pigment, commonly known white pigments can be used.

An example of a preferred composition is titanium oxide.

These include barium sulfate, calcium carbonate, aluminum oxide, lead oxide, silicon oxide, zirconium oxide, barium titanate, zinc sulfide, and antimony trioxide. Furthermore (D
), pigments with a refractive index of 205 or more are particularly preferred. Examples of these are zinc sulfide and antimony trioxide.

Titanium oxide, barium titanate, etc.

The average particle size of these white pigments varies depending on the film thickness of (D), but it is desirable that it is 20 μm or less, preferably 2 μm or less.

These white pigments may be used alone or in combination of two or more.

The weight ratio of polymer binder/white pigment is 100150
It is preferable that it is 500.

The thickness of (D) varies depending on the degree of coloring of each layer of (A), (B), and (C), but (A) / (B)
/ 51tm to hide the coloring consisting of (C)
It is preferable that it is 50 μm. From the viewpoint of resolution, it is more preferable that the width is from 3 μm to 30 ltm.

In the present invention, the white layer (D) may be a single layer in which the above-mentioned white pigment is uniformly dispersed in a polymeric binder, or may be a single layer in which the white pigment is uniformly dispersed in a polymer binder, or the white layer (D) may be a single layer in which the white pigment is uniformly dispersed in a polymer binder, or the white layer (D) may be a single layer in which the white pigment is uniformly dispersed in a polymer binder, or the white layer (D) may be a single layer in which the white pigment is uniformly dispersed in a polymeric binder, or the white layer (D) may be a single layer in which the white pigment is uniformly dispersed in a polymeric binder. It may be composed of two or more different layers, and it is useful for the present invention as long as it has an overall whiteness of 70 or more. Therefore, the whiteness may change continuously in the thickness direction.

In the present invention, methods for adding (C) and (D) on (B) include brush coating, dip coating, knife coating, roll coating, spray coating, and flow coating.

An electrophotographic photoreceptor can be manufactured by a commonly used coating method such as rotary coating (spinner, whey gel, etc.).

In the present invention, (A) /
(B) , (B) / (su, (su/ (D) ,
Other polymers or the like may be interposed between the two for the purpose of improving adhesiveness or the like.

Next, an example of a method of forming an electrostatic latent image on the electrophotographic photoreceptor and forming a toner image thereon according to the present invention will be described.

First, a charge is applied to the white layer (D) by a conventional method such as corona charging or tribocharging.

Next, the transparent organic photoconductive layer (C) is exposed to light from the plastic film layer (A) side through the transparent conductive layer (B). As a result, an electrostatic latent image is formed on the white layer (D). This electrostatic latent image is visualized using a commonly used dry or wet toner development method. When forming color images.

This operation was repeated three times for the three primary color toners, and if necessary, the same operation was repeated for the black toner to faithfully reproduce the colors of the original image on the white layer (D).] Obtain a toner image. be able to.

The electrophotographic photoreceptor thus obtained had a Hunter whiteness of 70 or more on its surface.

The visible image of the toner on the electrophotographic photoreceptor has good contrast, and especially when a color image is formed using color toner, it has an excellent ability to faithfully reproduce the colors of the original image, along with a white base. It will be done.

This means that the white layer (
D) It is particularly effective as a so-called CPC type electrophotographic photoreceptor for direct hard copying.

Furthermore, it can be used not only for copying machines, but also for facsimiles, printers, etc.

Toner transfer type or electrostatic latent image transfer (TESI:) type electrophotographic photosensitive master for plain paper (OPP),
Sarak is also effective as a thermoplastic electrophotographic photoreceptor.

Next, the whiteness used in the method of measuring whiteness used in the present invention is the one announced by Hunter at JO8A in the United States in October 1958.

That is, the whiteness W is expressed by the following formula.

,゛W = 100-C(100-,L)2+a2+'b
2) For measuring 2L, a, b, Kollmorgen.

Macbeth 2000 was used.

Regarding the image characteristics, the color images obtained by the above-described image forming method were evaluated by comprehensively evaluating the fidelity of color reproduction and resolution of the original image.

◎, very good ○: Good ×, defective classified into.

Next, the present invention will be explained based on examples.

Examples 1-4. Comparative Example 1 Pd with a surface resistance value of 104Ω was placed on a biaxially stretched polyester film (“Lumirror” manufactured by Toshi #) with a thickness of 100 μm.
Sputter so that it becomes /mouth.

A transparent conductive film was obtained.

Then, on the Pd of this transparent conductive film.

Take 100 g of brominated polyvinylcarbazole, 30 g of polycarbonate, and 0.5 g of benzopyrylium salt, and dissolve these in a mixed solution of IsK of 600 g of monochlorobenzene and 200 g of dichloroethane, and make a solution with a thickness of 10 μm after drying. I applied it with a metal link bar and dried it.

Furthermore, on top of this, acrylic ester copolymer resin 40
0g was dissolved in 3600g of toluene, this was divided into 4 portions, and 200g each of barium sulfate, zinc oxide, antimony trioxide, and titanium oxide were added and dispersed in each portion. The electrophotographic photoreceptor of the present invention (
Examples 1 to 4) were obtained. Example (1) obtained in this way
) to (4), the Hunter whiteness 1 image characteristics were as shown in Table 1. From these results, it is clear that the material according to the present invention has excellent surface whiteness and excellent image characteristics.

Further, in Examples (1) to (4), when paying attention to the refractive index of the pigment, it can be seen that titanium oxide and antimony trioxide having a refractive index of 205 or more are particularly excellent.

Next, the PdO of the conductive film obtained in Example (1) above was
Above, 100 g of acrylic ester copolymer resin was dissolved in butyl acetate to make a 1Qwt% solution, and to this, 300 g of zinc oxide, 60 mg of bromophenol blue,
A solution in which 60 mg of uranine was added and sufficiently dispersed was coated with a metering bar so that the thickness after drying was 20 μm, and dried for 1 hour to obtain an electrophotographic photoreceptor of Comparative Example (1). this·
- Lid - Whiteness 1 The image characteristics were as shown in Table 1. From these results, it can be seen that images with low whiteness do not have good single image characteristics.

Proceedings Amendment Written in 1949, 1, 2 by Kazuo Wakasugi, Commissioner of the Japan Patent Office 1. Description of the case 1982 Patent Application No. '118438 2. Name of the invention Electrophotographic photoreceptor and its photoreceptor Method of forming an electrolatent image 3 Relationship with the case of the person making the amendment Patent applicant address 2-2-5 Nihonbashi Muromachi, Chuo-ku, Tokyo Number of inventions increased by amendment None "Su" r Sn
, J.

(2) Same page 5, lines 8 to 10 Delete "It is preferable in the present invention."

(3) Same page 11, line 17 Correct "OPP" to "PPc".

Claims (1)

[Claims] (11J2 An external plastic film (A), a transparent conductive layer (B), a transparent organic photoconductive layer (C),...
and a white layer (D) having an inner whiteness of 70 or more. An electrophotographic photoreceptor characterized in that (A) / (B) / (C) / (D) are laminated in this order. (2) A transparent plastic film (A), a transparent conductive layer (B), a transparent organic photoconductive layer (C), and a white layer (D) having an interwhiteness of 70 or more. When forming an electrostatic latent image on an electrophotographic photoreceptor formed by laminating (A) / (B) / (C) / (D) in the order, an electric charge is applied to the surface of (A), and a charge is applied to the surface of (D). A method for forming an electrostatic latent image on an electrophotographic photoreceptor, the method comprising forming an electrostatic latent image on the surface of (A) by exposing from the side.