JPH02269357A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain the efficient electrophotographic sensitive body of a memory type by forming at least two photoconductive layers; an upper layer contg. a specific compd. and a lower layer which does not contain this compd. on a conductive base. CONSTITUTION:At least the two photoconductive layers; the upper layer contg. the compd. expressed by formula I (in the formula I, R<1> denotes a hydrogen atom, alkyl group or alkoxycarbonyl group; R<2> denotes a hydrogen atom or alkyl group) and the lower layer without contg. the above-mentioned compd. are provided on the conductive base. Namely, a coating liquid prepd. by dissolving polyvinyl carbazole, etc., as an electron donating compd. and 2,4,7- trinitrofluorenone, etc., as an electron acceptive compd. into an org. solvent is applied on the conductive base consisting of aluminum, etc., and the coating is dried to form the lower layer; thereafter, a liquid prepd. by adding the pyridinium iodide expressed by formula I to the above-mentioned coating liquid is applied thereon and the coating is dried to form the upper layer. The photosensitive body which has a high sensitivity and can be imparted with the memory characteristic at about the exposure necessary for the light attenuation of the photosensitive body is obtd. in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an electrophotographic photoreceptor having memory properties.

(Prior art) Among the basic processes of electrophotography: charging, exposure, development, and transfer, systems have been developed that omit the image exposure process and make multiple copies with a single exposure. There is. This system requires a photoreceptor with excellent so-called memory properties, which maintains photoconductivity after one image exposure, and therefore, research on imparting memory properties to photoreceptors has been actively reported. A common method for imparting memory properties is to add a memory imparting agent, such as leuco dye (Japanese Patent Application Laid-open No. 52-4839), protonic acid (U.S. Pat.
, 879.201 and 3,997.342, halides (U.S. Pat. No. 3,081.165), diazonium salts (Photographic 5science
and Engineering Volume 26, 6
9 (19B2)) have been proposed.

(Problems to be Solved by the Invention) Memory properties are imparted by adding the above-mentioned memory properties imparting agent, but in order to impart memory properties, long-term exposure is required, and diazonium salts, etc. Another problem is that it is easily decomposed by light and difficult to use repeatedly, making it difficult to put it into practical use.

(Means for Solving the Problems) The present inventors have arrived at the present invention as a result of intensive studies to solve the above problems. That is, an object of the present invention is to provide an efficient electrophotographic photoreceptor with memory property, and an object of the present invention is to provide an electrophotographic photoreceptor having the following general formula (1) (wherein R1 represents a hydrogen atom, an alkyl group, or an alkoxycarbonyl group, and R8 represents a hydrogen atom or an alkyl group. This is achieved by an electrophotographic photoreceptor having the following characteristics.

(for production) The present invention will be explained in detail below.

First, R1 in the general formula (1) in the present invention is a hydrogen atom, an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group, an alkoxycarbonyl group such as a methoxycarbonyl group, an ethoxycarbonyl group, a butoxycarbonyl group, etc. is used, R2 is a hydrogen atom, a methyl group,
Alkyl groups such as ethyl, propyl, butyl and hexyl groups are used.

The electrophotographic photoreceptor of the present invention is formed by laminating at least two types of photoconductive layers on a conductive support. As the conductive support, a drum or sheet of metal such as aluminum or brass, an insulating plastic film or sheet of polyester or polyimide, or paper whose surface has been treated to make it conductive are used. Examples of the conductive treatment include a method of forming a metal layer such as aluminum, gold, or silver, or a so-called transparent conductive layer such as indium oxide or tin oxide by a method such as one-layer coating or sputtering.

The photoconductive layer of the photoreceptor of the present invention may be of any type, including known types such as a charge transfer complex type, a dye-sensitized type, and a functionally separated type, but a charge transfer complex type is preferred.

The charge transfer complex type photoconductive layer consists of a photoconductive charge transfer complex formed by mixing an electron donating compound and an electron accepting compound.

Examples of electron-donating compounds include polyvinylcarbazole, polyvinylanthracene, polyacenaphthylene,
Examples include photoconductive polymers such as polystyrylanthracene and polyvinylpyrene, nitrogen-containing heterocyclic compounds such as oxadiazole, pyrazoline, and isoxazole, and low-molecular compounds such as hydrazone compounds and triarylamine.

Examples of electron-accepting compounds include 2.4.7-dolinitrofluorenone, 2,4.5.7-titranitrofluorenone, tetracyanoethylene, tetracyanoquinodimethane, chloranil, bromanil, and terephthalalmalononitrile. Examples include compounds called Lewis acids.

The electron-accepting compound is 0.05 to 1.3 mol per 1 mol of the electron-donating compound (monomer unit in the case of a polymer);
It is preferably used in a proportion of 0.1 to 1.1 mol.

Preferred combinations of these linings include polyvinylcarbazole and 2,4,7-dolinitrofluorenone. For the photoconductive layer, a binder polymer, a plasticizer, a stabilizer such as an antioxidant, etc. can be added to the charge transfer complex, if necessary. Examples of the binder polymer include polyester, polycarbonate, methacrylic resin, polyarylate, polysulfone, and the like. The photoconductive layer of the photoreceptor of the present invention is prepared by applying a coating solution prepared by dissolving the composition of the photoconductive layer described above and other components as necessary in an organic solvent onto the conductive support, drying, and removing the lower layer. After the formation, a solution obtained by adding a collated pyridinium represented by the general formula (1) to the previous coating solution is applied onto the lower layer and dried to form an upper layer. Although it is possible to use a coating solution with a completely different composition from the coating solution for the lower layer for forming the upper layer, in that case, a clear interface will be formed between the upper layer and the lower layer, which is undesirable. It is preferable to add only pyridinium iodide to the solution and use it for forming the upper layer.

The amount of the binder polymer may be the same as that of known electrophotographic photoreceptors. For example, when a polymer such as polyvinylcarbazole is used as an electron donating compound, it is not necessarily necessary to use another polymer as a binder. Other polymers are suitably selected and used as a binder within a range that does not impair the desirable effects of carbazole as an electron-donating compound, that is, within a range of 50 parts by weight or less per 100 parts by weight of polyvinylcarbazole, etc., and used as a binder in the photoreceptor of the present invention. The pyridinium iodide represented by the general formula (1) is preferably 0.0.
It is added in an amount of 5 to 20 parts by weight. Preferably it is 1 to 10 parts by weight.

(Example) Examples of the present invention are shown below, but the present invention is not limited thereto.

Example A transparent conductive layer called ITO made of indium oxide and tin oxide was formed on a polyester film, and 2,4.7-dolinitrofluorenone (TNF
) Tetrahydrofuran (T
HF) solution was applied and dried to obtain a photoconductive layer with a thickness of about 5 μm.

On top of this, a coating solution in which 1-ethyl-4-methoxycarbonylpyridinium iodide was further added to the coating solution at a ratio of 0.05 mol was coated in the same manner and dried to obtain an upper layer. Ta. As a result, a photoreceptor containing pyridinium iossite in the upper layer of the photoconductive layer was obtained.

The electrophotographic properties of this photoreceptor were measured using an electrostatic copying paper tester (Model 5P-428 manufactured by Kawaguchi Electric Seisakusho).

Perform corona charging (applied voltage -8 kV) in the dark, and
It was irradiated with nm monochromatic light for 3 seconds at an exposure intensity of O, ld/cd.

The surface potential of the photoreceptor immediately after corona charging is V The exposure amount required to reduce the surface potential by half was determined as sensitivity (half-reduction exposure amount, E17□l)).

Subsequently, the process from charging to exposure described above was repeated in exactly the same manner, and the surface potential immediately after charging (1), 8, the dark decay depth, and the half-reduced exposure amount E, /2 (1) were measured.

Surface potentials v, l and v3! was used as an index of memory performance. That is, the memory property was evaluated by the value of.

If there is no memory property, the value of vl does not change, so it becomes F, -0, and if the memory property is large, the value of F, also increases, and the maximum value is 100.

The measured values are shown in Table 1.

The results revealed that this photoreceptor exhibits extremely large memory properties with a smaller exposure amount required for sensitivity measurement than conventional memory photoreceptors. When re-measured the next day with memory properties added, it was found that the memory properties were maintained.

When this photoreceptor was placed in a dry base at 100° C. for 10 minutes, the memory property, that is, the continuous photoconductivity after a single exposure, disappeared.

On the other hand, when this photoreceptor was charged at +8 kV, vo was as small as +50V and the dark decay was large, indicating that it is preferable to use the photoreceptor with negative charging as a memory photoreceptor.

Comparative Example The order of coating the photoconductive layer was reversed from that of the previous example.
Similarly, a photoreceptor containing pyridinium iosite only in the lower layer of the photoconductive layer was obtained.

Table 1 shows the evaluation results of memory properties.

As is clear from Table 1, the photoreceptor of the comparative example had poor charging properties (and almost no memory properties). It has been shown that something is necessary.

Table (Effects of the Invention) According to the present invention, it is possible to obtain a memory photoreceptor that has high sensitivity and can impart memory properties with an exposure amount necessary for light attenuation of the photoreceptor.

Applicant Mitsubishi Kasei Corporation Representative Patent Attorney Hase 1 other person

Claims (1)

[Claims] (1) There is the following general formula (I) ▲mathematical formula, chemical formula, table, etc. on the conductive support▼...(I) (In the formula, R^1 represents a hydrogen atom, an alkyl group, or an alkoxycarbonyl group, and R ^2 represents a hydrogen atom or an alkyl group.) An electrophotographic photoreceptor comprising at least two photoconductive layers: an upper layer containing a compound represented by the following formula and a lower layer not containing the compound.