JPS6325661A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To prevent rise of residual potential under low humidity and to improve deterioration of characteristics at the time of repeated uses without affecting photosensitive characteristics by incorporating metallocene in an interlayer between a conductive substrate and a photosensitive layer. CONSTITUTION:The interlayer formed between the conductive substrate and the photosensitive layer contains metallocene, and this interlayer is obtained, preferably, by coating the substrate with a coating fluid containing metallocene and drying it. A binder resin, such as polyvinyl alcohol, sodium polyacrylate, CMC, or casein, is used. Metallocene is contained, preferably, in an amount of 0.1-50wt% of the binder. When needed, TiO2, ZnO, or the like inorganic pigments may be added to the interlayer, preferably, in an amount of 5-1,000wt% of the binder.

Description

Detailed Description of the Invention [Technical Field] The present invention relates to an electrophotographic photoreceptor, and more particularly, to improvement of an intermediate layer in an electrophotographic photoreceptor repeatedly used in PPC copiers, laser beam printers, digital copiers, etc. .

[Prior Art] In general, electrophotographic photoreceptors that are used repeatedly (hereinafter sometimes simply referred to as "photoreceptors") must have good charging properties (by preventing unnecessary charge injection and An intermediate layer made of a resin with relatively low resistance is provided between the substrate and the photosensitive layer in order to maintain charge acceptance) and to ensure good adhesion of the photosensitive layer to the substrate. .

Conventional intermediate layer resins include (a) water-soluble v! such as casein and polyvinyl alcohol; ! (b) Polyamide resins such as nylon and copolymerized nylon.

(c) Photoreceptors or thermosetting resins have been used, but photoreceptors with intermediate layers formed with these resins have high resistance at low humidity, resulting in increased residual charge and sensitivity. There is a tendency for this to decline.

As a means of resolving these inconveniences, it is possible to add conductive pigments such as indium oxide, tin oxide, and carbon to the middle 1m layer (Japanese Patent Laid-Open No. 58-93063), or to add a conductive polymer (Japanese Patent Laid-Open No. 58-93063). 58-9574
Publication No. 4) have been proposed. However, in the former case, the charging property decreases, so a second intermediate layer consisting only of resin must be formed between the conductive pigment-containing intermediate layer and the photosensitive layer, and in the latter case, the charging property decreases. Although the performance does not deteriorate, a decrease in sensitivity is observed, which poses a practical problem.

Furthermore, in so-called laminated photoreceptors in which the photosensitive layer has a laminated structure of a charge generation layer and a charge transport layer, moiré tends to occur due to multiple reflections between the substrate and the surface of the charge transport layer. It has also been proposed that the layer contain substances that scatter light. However, even in this photoreceptor, a decrease in chargeability and an increase in residual potential have been observed with repeated use, and similar to the photoreceptor described above, improvements are required.

[Purpose] An object of the present invention is to provide an electrophotographic photoreceptor that eliminates humidity dependence (residual potential increase at low humidity) without affecting the photoreceptor characteristics, and further improves deterioration of characteristics during repeated use. It is something to do.

[Structure] The present invention is an electrophotographic photoreceptor that has an intermediate layer between a conductive substrate and a photosensitive layer and is used repeatedly, characterized in that the intermediate layer contains a metallocene.

Incidentally, the present inventor has confirmed that the increase in residual potential in a low humidity environment can be suppressed by adding metallocene to the intermediate layer. The present invention was completed based on this knowledge.

The present invention will be explained in more detail below. As mentioned above, the photoreceptor of the present invention has a structure in which an intermediate layer and a photosensitive layer are sequentially laminated on a conductive substrate. Conductive substrates include aluminum, nickel, stainless steel, etc.; plastics with conductive pigments such as carbon dispersed; metals deposited on insulating supports (such as plastics or plastic films) or conductive paints. An example is a coated one.

The "metallocene" contained in the intermediate layer is composed of two cyclopentadiene rings and various transition metals.

In the metallocene, the transition metal M is Fe, Ti, V, or Cr.

M ng Cot Nil MOL Rug Lu, T
ag WrO5°Ir etc. is biscyclopentadienyl complex salt (CsHs) 2M. Metallocene is a tricyclopentadienyl compound (C,H,)3M when the transition metal M is Sc, Y, etc. In addition, metallocenes with large atomic numbers such as Re and Rh are in the form of hydrides (C
,H,) and MH.

The intermediate layer in the present invention is preferably formed by applying a liquid containing such a metallocene and a binder onto a conductive support and drying it.The binder used here is polyvinyl alcohol, polyvinyl alcohol, etc. Examples include sodium acrylate, CMC, casein, sodium alginate, nylon, copolymerized nylon, and alkoxymethylated nylon.

The appropriate mixing ratio of metallocene and binder is about 0.1 to 50 parts by weight of metallocene to 100 parts by weight of binder.

In addition, for the intermediate layer, titanium dioxide, zinc white,
Inorganic pigments such as zinc sulfide, white lead, lithopone, calcium carbonate, alumina, barium sulfate, and white carbon may also be included.

When containing inorganic pigments, binders, metallocene,
The inorganic pigment and a solvent are placed in a ball mill or the like to disperse the inorganic pigment well, and the resulting dispersion is applied onto a conductive support.
Just let it dry.

The amount of inorganic pigment added to the intermediate layer cannot be uniformly determined depending on the material used, but it is 10 parts by weight of the binder.
It is not more than 0.05 to 10 parts by weight, preferably about 0.05 to 10 parts by weight.

Note that the thickness of the intermediate layer is approximately 0.3 to 20 μm.

The photosensitive layer is formed by (1) forming a charge transfer complex by combining an electron-donating compound and an electron-accepting compound;
P 3484237 D-I, Q), (2) Organic light 41
71 bodies sensitized by adding dye (Special Publication Publication 1977-2)
5658), (3) Pigment dispersed in a hole- or electron-active matrix (Japanese Patent Application Laid-Open No. 1983-1999).
30328, JP-A-47-18545, etc.), (4) functionally separated charge generation layer and charge transport layer (described in JP-A-49-105537), (
5) those whose main component is a eutectic chain consisting of a dye and a resin (described in JP-A-47-10785), (6) those in which an organic pigment or an inorganic charge-generating material is added to a charge transfer complex ( It may be formed of any conventionally known organic photoconductor such as those described in Japanese Patent Application Laid-open No. 49-91648.

However, among these, the laminated photoreceptor of type (4) is especially advantageous because it has high sensitivity and can be selected from a variety of materials depending on the function.

The charge-generating layer is made of polyester, charge-generating substances such as azo pigments, phthalocyanine pigments, square link pigments, indigo pigments, perylene pigments, selenium powder, selenium alloy powder, amorphous silicon powder, zinc oxide powder, and cadmium sulfide powder. It is formed by dispersing in a solution of a binder resin such as polycarbonate, polyvinyl butyral, or acrylic resin, and coating this on the intermediate layer. The appropriate thickness of the charge generation layer is about 0.01 to 2 μm.

The charge transport layer is an α-phenylstilbene compound (Japanese Patent Application Laid-open No.
8-198043), hydrazone compounds (
A charge transporting substance such as those described in JP-A No. 55-46760 is dissolved in a film-forming resin such as polyester, polysulfone, polycarbonate, polymethacrylic acid ester, polystyrene, etc., and this is applied onto the charge generation layer. It may be applied to a thickness of about 10 to 30 μm. The film-forming resin is used here because the charge transporting substance generally has a low molecular weight and has poor film-forming properties by itself.

The photoreceptor thus manufactured is suitable for repeated use, and if necessary, a protective layer similar to conventional methods can be provided on the surface of the photoreceptor layer.

Next, examples and comparative examples will be shown. All parts herein are parts by weight.

(Left below) Example 1 Alcohol-soluble copolymerized nylon (CM-40 manufactured by Toshisha Co., Ltd.)
00) Log was dissolved in 90 g of methanol. While stirring this solution, a solution Log obtained by dissolving 2 parts of ferrocene [(csH,)2Fe) in 8 parts of tetrahydrofuran was added dropwise. The obtained coating solution was dip-coated onto the surface of a 0.2 mm thick aluminum plate (conductive substrate), and then
It was dried at °C for 10 minutes to form an intermediate layer with a thickness of about 2 μm.

On the other hand, polyester resin (Bylon 200 manufactured by Toyobo Co., Ltd.)
) was dissolved in 150 g of cyclohexanone, and a bisazo pigment Log represented by the following structural formula was added thereto to form a ball.

Dispersion was carried out for 48 hours in a vacuum chamber. Subsequently, 210 g of cyclohexanone was added to this mixture and dispersed for 3 hours, then poured into a container and diluted with cyclohexanone while stirring to give a charge generation layer forming liquid to a solid content of 1% by weight. Prepared.

This solution was dip coated onto the intermediate layer and dried at 130° C. for 10 minutes to form a charge generation layer with a thickness of about 0.3 μm.

In addition, polycarbonate resin (Teijin Panlite)
1300) was dissolved in 90 g of tetrahydrofuran, and 7 g of a charge transport substance represented by the following structural formula was dissolved therein. The solution was applied by dip coating onto the charge generation layer, and dried at 130°C for 20 minutes to form a layer with a thickness of about 20 μm. A charge transport layer was formed to produce a laminated electrophotographic photoreceptor.

Comparative Example 1 A comparative photoreceptor was prepared in exactly the same manner as in Example 1 except that metallocene C (c, H, ), Fe) was removed from the intermediate layer.

Example 2 Alcohol-soluble copolymerized nylon (CM-8 manufactured by Toshi Co., Ltd.)
000) Log was dissolved in 90 g of methanol.

Add titanium oxide powder (Tiebake R-6 manufactured by Ishihara Sangyo Co., Ltd.) to this.
80) and 5 g of ferrocene were added and dispersed in a ball mill for 24 hours. The obtained coating liquid was 0.2 m
After coating the surface of a m-thick aluminum plate (conductive substrate) by dip coating, the mixture was dried at 130° C. for 10 minutes to form an intermediate layer with a thickness of about 2 μm.

On the other hand, butyral resin (Nisrex BL manufactured by Tanezu Kagaku Co., Ltd.)
-3) 5g was dissolved in 150g of cyclohexanone, trisazo pigment Log having the following structural formula was added thereto, and the mixture was dispersed in a ball mill for 48 hours. Subsequently, cyclohexanone was added to this mixture so that the solid content was 1.0% by weight, and the mixture was stirred to prepare a charge generation layer forming liquid.

This solution was dip coated onto the intermediate layer and dried at 130°C for 10 minutes to form a charge generation layer with a thickness of about 0.3 μm.

In addition, polycarbonate resin (for Ontaisha Panlite)
1300) 12g of the charge transport material dissolved in 90g of tetrahydrofuran and 7g of the charge transport substance represented by the following structural formula dissolved therein was applied by dip coating onto the charge generation layer, and dried at 130°C for 20 minutes to form a charge transport material with a thickness of about 20μm. A layered electrophotographic photoreceptor was prepared by forming layers.

Comparative Example 2 A comparative photoreceptor was prepared in exactly the same manner as in Example 2 except that ferrocene was removed from the intermediate layer.

Example 3 Titanocene C (C,
A laminated electrophotographic photoreceptor was produced in exactly the same manner as in Example 1 except that Hs)2Tx] was used.

Example 4 Nilakerocene ((C
A laminated electrophotographic photoreceptor was produced in exactly the same manner as in Example 2 except that s Hs )2N l) was used.

These samples (4 types of photoreceptors of the present invention, 2 types of comparative photoreceptors)
The characteristics of the photoreceptor were measured using an electrostatic paper analyzer SP-428 (manufactured by Kawaguchi Electric Seisakusho Co., Ltd.) under the following conditions.

Furthermore, after the photoreceptor was fatigued by simultaneously performing charging and exposure under the above conditions for 30 minutes, the characteristics of the photoreceptor were further measured.

The above results are shown in Table-1. However, Vm in the table is
The surface potential Vo after 10 seconds of charging is: The surface potential E after 10 seconds of dark decay, i. teeth,
The exposure amount vR required to reduce the post-exposure potential to one-tenth means the potential 15 seconds after exposure.

(The following is a blank space) Table 1 [Effects] As is clear from the description of the examples, by including metallocene in the intermediate layer, a photoreceptor with high sensitivity and less fatigue can be obtained in both a low humidity environment and a room temperature environment.

Claims (1)

[Claims] 1. An electrophotographic photoreceptor that has an intermediate layer between a conductive substrate and a photosensitive layer and is used repeatedly, wherein the intermediate layer contains a metallocene.