JPS63106662A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To improve sensitivity and durability of the titled body and stability of the titled body at the time of a repeated use by forming a photosensitive layer contg. a specific porphyrin compd. on a conductive substrate body. CONSTITUTION:The photosensitive layer contg. the porphyrin compd. shown by formula I or II is formed on the conductive substrate body. In formulas I and II, M is a metal atom selected from copper, cobalt, iron, nickel, zinc and manganese or metal chlorides thereof. X is hydrogen or halogen atom, methyl, nitro or methoxy group. Thus, the titled body having excellent coated film characteristics and electrophotographic characteristics such as charge holding power, sensitivity, residual potential, etc., and having less tendency for generating deterioration due to fatigue is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a photoreceptor for electrophotography. Specifically, the present invention relates to a novel electrophotographic photoreceptor having a photosensitive layer containing a porphyrin compound.

More specifically, the present invention relates to a highly durable electrophotographic photoreceptor that has high sensitivity and is suitable for repeated use.

Conventional technology Conventionally, photoreceptors for electrophotography have been made of selenium, zinc oxide,
Those having a photosensitive layer mainly composed of an inorganic photoconductor such as cadmium sulfide were widely known.

However, these are not necessarily satisfactory in terms of sensitivity, thermal stability, moisture resistance, durability, etc., and in particular, selenium and cadmium sulfide have limitations in production and handling due to their toxicity.

On the other hand, electrophotographic photoreceptors having a photosensitive layer containing an organic photoconductive compound as a main component are relatively easy to manufacture, inexpensive, and easy to handle. It has many advantages, such as superior thermal stability, and has attracted a lot of attention in recent years.

On the other hand, in laminated or dispersed function-separated photoreceptors, in which the carrier generation function and the carrier transport function are assigned to separate substances, each material can be selected from a wide range, and the charging characteristics, sensitivity, In terms of electrophotographic properties such as durability, it has the advantage that an electrophotographic photoreceptor having arbitrary properties can be produced relatively easily.

Problems to be Solved by the Invention However, electrophotographic photoreceptors having a photosensitive layer containing an organic photoconductive compound as a main component are not necessarily satisfactory in terms of sensitivity and durability.

For example, poly-N-vinylcarbazole is well known as an organic photoconductive compound, and 2.4.7
An electrophotographic photoreceptor having a photosensitive layer mainly composed of a charge transfer complex formed from a Lewis acid such as -dolinitro-9-fluorenone does not have sufficient sensitivity and durability.

Furthermore, for functionally separated photoreceptors, various carrier-generating substances or carrier-transferring substances have been proposed. Electrophotographic photoreceptors having a photosensitive layer combined with a carrier transport layer have been put into practical use. However, the carrier generation layer made of amorphous selenium has the disadvantage that its photosensitivity is not so high and its durability is poor.

In addition, various proposals have been made to use photographic dyes and pigments as carrier-generating substances, such as phthalocyanine,
Products using dyes and pigments such as azo, perylene, squarylium, polymethine, and azulenium are already known.

However, electrophotographic photoreceptors using these dyes and pigments are not always satisfactory in terms of characteristics such as sensitivity or stability when used repeatedly, and the selection range of carrier transfer substances is also limited. The reality is that nothing that fully satisfies the wide range of demands of electrophotographic processes, such as the above, has yet to be obtained.

The present invention has been made in view of the above circumstances.

Therefore, an object of the present invention is to provide an electrophotographic photoreceptor with high sensitivity, low residual potential, and excellent durability whose characteristics do not change even after repeated use.

Means for Solving the Problems The inventors of the present invention should achieve the above objectives (as a result of intensive research,
The present invention was completed by discovering that a porphyrin compound represented by the following general formula can function as an active ingredient of a photoreceptor.

That is, the electrophotographic photoreceptor of the present invention has a photosensitive layer containing a porphyrin compound represented by the following general formula (I) or (n) on a conductive support (where M is copper, cobalt, or iron). , a metal selected from nickel, zinc and manganese, or a chloride of these metals, and X represents a hydrogen atom, a halogen atom, a methyl group, a nitro group or a methoxy group. By using the porphyrin compound represented by the above general formula as a photoconductive substance constituting the photosensitive layer of an electrophotographic photoreceptor, or by utilizing only the excellent carrier generation ability of the porphyrin compound, this can be used to generate and move carriers. By using it as a carrier generating material in a so-called function-separated type electrophotographic photoreceptor, in which separate substances are used for each, it has excellent coating properties, excellent electrophotographic properties such as charge retention, sensitivity, and residual potential, and can be used repeatedly. In addition to having little fatigue deterioration, the above-mentioned characteristics do not change even when exposed to heat or light.
It is possible to create an electrophotographic photoreceptor that can exhibit stable characteristics.

The porphyrin compounds represented by the general formulas (I> and (II)) are synthesized by conventional synthesis methods as shown in the following literature.

Literature on synthesis ○ J, B, im, J, J, Leonard, an
d F, R, Longo: J, Am.

Chem, Soc., 94.3986 (1972).

O.A., D., Adler, F.R., Longo, J.
D., Finarelli, J.

Goldmacher, J., As5our, and
L, Karsakoff: J.

Ora, Chem, 32.476 (1967).

O German Patent Publication 2.308252 (BASFAG) O
H, W, Whitlock and )1. Y, 0es
ter: J, Am, Chem.

Soc, 95.5738 (1973).

(Synthesis Example 1) Propionic acid (60 ml) was heated to 115°C, and a mixture of pyrrole (2,68 g, 0.0400 mol) and benzaldehyde (4,249,0,0400 mol) was added dropwise over 40 minutes while stirring. do. 10 minutes after starting the dropwise addition of the pyrrole and benzaldehyde mixture, naphthoquinone (
1,589,0,0100 mol) of propionic acid solution (
30af) was added dropwise over 30 minutes. Add 3 more reaction mixture
After heating and stirring at 115°C for 0 minutes, the mixture was cooled to 5°C, and the precipitated crystals were filtered, washed with cold methanol, and dried to obtain 1.
98 g (0,00322 mol) of men-tetraphenylporphine are obtained. Yield 32%.

Repeated recrystallization from a methanol-chloroform mixed solvent yielded pure meso-tetraphenylporphine (HPLC).
ASSa'/≧99.9%) is obtained.

(Synthesis Example 2) Meso-tetraphenylporphine (1.20g, 0.0
0196 mol) and zinc acetate (1.03 g) in pyridine (
100me) and heat and stir at 100°C for 4 hours. The reaction mixture was cooled, extracted by adding benzene and water, the solvent of the organic layer was distilled off, recrystallized from benzene, and then heated and dried for 10 hours to give a yield of 0.81! iF (0,00119 mol)
, to obtain zinc tetraphenylporphine.

Yield 61%.

The electrophotographic photoreceptor of the present invention has the general formulas (I> and (I
It is characterized by containing one or more porphyrin compounds represented by [>].

The photosensitive layer of the electrophotographic photoreceptor of the present invention may generally have any of the forms shown below.

■Photosensitive layer consisting only of a porphyrin compound■Photosensitive layer consisting of a porphyrin compound dispersed in a binder■Photosensitive layer consisting of a porphyrin compound dispersed in a layer containing a well-known charge transfer substance ■Photosensitive layer of the above A photosensitive layer formed by laminating a charge-generating layer and a charge-transfer layer containing a well-known charge-transfer substance. FIG. A charge generation layer 2 and a charge transfer layer 1 are sequentially laminated on a conductive support 3 to form a photosensitive layer 4.
is formed.

FIG. 2 is a diagram illustrating the structure of an electrophotographic photoreceptor having photosensitive layers of types 1 to 2, in which a photosensitive layer 4 is provided on a conductive support 3. In FIG.

The porphyrin compound represented by the above general formula generates charge carriers with extremely high efficiency when it absorbs light.

The generated carriers can be transferred using a porphyrinated compound as a medium, but it is preferable to use a well-known charge transfer substance as a medium.From this point, ■ and ■
Particularly preferred is a photosensitive layer having the form:

Charge transfer substances are generally classified into two types: electron transfer substances and hole transfer substances, but both can be used in the photosensitive layer of the photoreceptor of the present invention, and a mixture of substances having the same type of function can be used. Also, a mixture of materials having different functions can be used. Substances that cause electron transfer include electron-withdrawing compounds having electron-withdrawing groups such as nitro groups, cyano groups, and ester groups.
゜4.7-Trinitrofluorenone, 2,4,5゜7-
nitrated fluorenones, such as titranitrofluorenone;
Alternatively, tetracyanoquinodimethane, tetracyanoethylene, 2,4,5.7-titranitroxanthone, 2
, 4,8-trinidrothioxanthone, and polymerized compounds of these electron-withdrawing compounds.

Further, examples of electron-donating organic photoconductive compounds as hole transport media include the following.

[Hydrazones] 2H5 C2! X5? 2H5 [Pyrazolines] [Diarylalkane] υ2H5 H3 (1cu2)2N-Q-an, aN(an, (3)2[
Alkylene diamines] [Dibenzylanilines] [Triphenylamines] [Diphenylbenzylamines] [Triarylalkanes] H3 13 in 36 [Oxadiazoles] [Anthracenes] [Oxazoles] Others, high As the molecular compound, poly-N-vinylcarbazole, halogenated poly-N-vinylcarbazole, polyvinylpyrene, polyvinylanthracene, polyvinylacridine, polyglycidylcarbazole tylcarbazole-formaldehyde resin, etc. can also be used.

The electrophotographic photoreceptor of the present invention can be manufactured according to a conventional method.

For example, an electrophotographic photoreceptor having a photosensitive layer of the type (2) can be prepared by using a coating solution obtained by dissolving or dispersing the porphyrin compound represented by the general formula <I> or (II) in an appropriate medium. It can be manufactured by coating on a conductive support and drying to form a photosensitive layer having a thickness of usually several μm to several tens of μm.

Media used for preparing the coating solution include: ethers such as tetrahydrofuran and 1,4-dioxane; ketones such as methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene and xylene; N,N-dimethylformamide, acetonitrile, N - Aprotic polar solvents such as methylpyrrolidone and dimethyl sulfoxide; Alcohol solvents such as methanol, ethanol, and isopropanol; esters such as ethyl acetate, methyl acetate, and methyl cellosolve acetate; chlorinated hydrocarbons such as dichloroethane and chloroform; Can be mentioned.

When a photosensitive layer is formed by dispersing a porphyrin compound in a binder, the particle size of the porphyrin compound is preferably 5 μm or less, preferably 3 μm or less, and most preferably 1 μm or less.

Furthermore, as the conductive support on which the photosensitive layer is formed, any of those employed in well-known electrophotographic photoreceptors can be used. Specifically, examples include metal drums and sheets made of aluminum, copper, etc., and laminates and vapor deposits of these metal foils. Furthermore, plastics are coated with conductive substances such as metal powder, carbon black, copper iodide, and polymer electrolytes along with a suitable binder.
Examples include film, plastic drum paper, and the like.

Further examples include plastic sheets and drums that contain conductive substances such as metal powder, carbon black, and carbon fibers and are made conductive.

An electrophotographic photoreceptor having a photosensitive layer of type (2) above can be produced in the same manner as described above by dissolving a binder in the coating liquid used to form the photosensitive layer of type (2). In this case, the medium of the coating liquid is preferably one that dissolves the binder.

As binders, polymers and copolymers of vinyl compounds such as styrene, vinyl acetate, acrylic esters, methacrylic esters, phenoxy resins, polysulfones, arylate resins, polycarbonates, polyesters,
Examples include various polymers such as cellulose ester, cellulose ether, urethane resin, epoxy resin, and acrylic polyol resin.

The amount of binder used is usually in the range of 0.1 to 5 times the weight of the porphyrin compound.

In addition, when forming this type of photosensitive layer,
It is desirable that the porphyrin compound be present in the binder in the form of fine particles, for example, with a particle size of 3 μm or less, particularly 1 μm or less.

Similarly, an electrophotographic photoreceptor having a photosensitive layer of the type (2) above can be manufactured by dissolving a charge transfer medium in the coating liquid used in forming the photosensitive layer of the type (2).

As the charge transfer medium, any of those exemplified above can be used.

Although charge transfer media such as polyvinylcarbazole and polyglycidylcarbazole can be used as binders themselves, when using other materials, it is desirable to use a binder.

As the binder, any of those exemplified above can be used. In this case, the amount of binder used is usually 5 to 10 times the weight of the porphyrin compound, and the amount of charge transfer medium used is usually 0.2 times the weight of the binder.
The amount is in the range of 1.5 times by weight, preferably 0.3 to 1.2 times by weight.

In the case of a charge transport medium which itself can be used as a binder, it is usually used in an amount of 5 to 20 times the weight of the porphyrin compound.

In this type of photosensitive layer, similarly to the photosensitive layer of type (1) above, it is preferable that the porphyrin compound is present in the charge transport medium and the binder in the form of fine particles.

An electrophotographic photoreceptor having a photosensitive layer of type (1) above is prepared by coating a coating solution obtained by dissolving a charge transfer medium in an appropriate medium on the photosensitive layer of types (1) to (4) above, and drying the coating solution to form a charge transfer layer. It can be formed and manufactured. In this case, the photosensitive layers of the types (1) to (4) above serve as charge generation layers.

In the present invention, in this case, the charge transport layer is not necessarily provided above the charge generation layer, but may be provided between the charge generation layer and the conductive support. However, the former is preferable in terms of durability.

The charge transfer layer is formed by the same method as in forming the photosensitive layer described in (2) above.

That is, the coating liquid for forming the photosensitive layer described in (1) above, except that the porphyrin compound is removed, may be used as the coating liquid. Typically, the charge transport layer is formed to a thickness of 5 to 50 μm.

The photosensitive layer of the electrophotographic photoreceptor of the present invention may contain a known sensitizer. Suitable sensitizers include Lewis acids and dyes that form charge transfer complexes with organic photoconductive materials.

Examples of Lewis acids include chloranil, 2°3-dichloro-1,4-naphthoquinone, 2-methylanthraquinone, 1-nitroanthraquinone, 1-chloro-5-nitroanthraquinone, 2-chloroanthraquinone, and phenanthrenequinone. Quinones, aldehydes such as 4-nitrobenzaldehyde, ketones such as 9-benzoylanthracene, indanedione 3,5-dinitrobenzophenone, 3.3',-5,5''-tetranitrobenzophenone, phthalic anhydride, 4 - Acid anhydrides such as chlornaphthalic anhydride, cyano compounds such as tetracyanoethylene, terephthalmalononitrile, 4-nitrobenzalmalonitrile, 3-benzalphthalide, 3-(α-
Examples include electron-withdrawing compounds such as cyano-p-nitrobenzal) phthalide and 3-(α-cyano-p-nitrobenzal) phthalide.

Examples of dyes include triphenylmethane dyes such as methyl violet, brilliant green, and crystal violet, thiazine dyes such as methylene blue, quinone dyes such as quinizarin, and cyanine dyes, pyrylium salts, thiapyrylium salts, and benzobyrylium salts. .

In addition, it may contain inorganic photoconductive fine particles such as selenium and selenium-arsenic alloys, and organic photoconductive pigments such as copper phthalocyanine pigments and perylene pigments.

Furthermore, the photosensitive layer of the electrophotographic photoreceptor of the present invention has film formability,
It may contain a well-known plasticizer to improve flexibility and mechanical strength.

As plasticizers, phthalate esters, phosphate esters,
Examples include aromatic compounds such as epoxy compounds, chlorinated paraffins, chlorinated fatty acid esters, and methylnaphthalene.

EXAMPLES Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to the following Examples unless the gist thereof is exceeded.

Examples 1 to 6 γ-aminopropyltriethoxysilane (trade name A-1
A solution obtained by dissolving 1 part by weight of 100 (manufactured by Nippon Unicar) in 100 parts by weight of ethyl alcohol is applied onto a conductive support made of a polyester film laminated with aluminum foil, dried, and dried to a thickness of 0. An intermediate layer of 0.3 μm was provided. 2 g of each compound shown in the following table and 2 g of polyarylate resin (U-100 manufactured by Unitika) were added to 1,
In addition to 100 y of 2-dichloroethane, a dispersion obtained by dispersing in a paint shaker for about 1 hour is applied onto the intermediate layer so that the film thickness after drying is 0.5 μm, dried, and charged. A generation layer was formed. Furthermore, the carrier transfer substance N, N''-diphenyl-N, N''-bis(
3-methylphenyl)-[1,1”-biphenyl]-4
A solution obtained by dissolving 1 g of ,4-diamine and 1 g of polycarbonate resin (trade name Panlite L-1250 manufactured by Teijin Kasei N) in 8 g of methylene chloride was used to obtain a solution with a film thickness of 1 after drying.
It was coated on the charge generation layer to a thickness of 2 μm and dried to form a charge transfer layer, thereby producing an electrophotographic photoreceptor. After storing this electrophotographic photoreceptor in a dark place at room temperature for one week,
It was attached to an electrostatic paper tester [5P-428J (newly manufactured by Kawaguchi Denki Seisaku), and the following characteristic tests were conducted.

That is, a voltage of -6 kV is applied to the charger to charge the photosensitive layer by corona discharge for 5 seconds, and the potential at that time Vo (-
V) is measured, and then the illuminance on the surface of the photosensitive layer is 301
Irradiate light from a halogen lamp in the state of uX,
The exposure amount E1/2 (1ux - 5ec) required to attenuate the surface potential of the photosensitive layer to 1/2 was determined.

The charging characteristics and half-decrease exposure amount of these electrophotographic photoreceptors are shown in the following table.

Charge characteristics of porphyrin compound used and half-decreased exposure amount Examples 7 to 9 γ-Aminopropyltriethoxysilane (trade name A
-1100, manufactured by Nippon Unicar Flavor), thickness 0.03
After drying, a dispersion obtained by adding 4 g of each compound shown in the following table to 400 ml of cyclohexanone and dispersing it for 2 hours using a paint shaker was applied to the intermediate layer. A charge generation layer was formed by coating and drying to a film thickness of 0.3 μm. On this charge generation layer, 12 g of a stilbene compound represented by the following structural formula was placed along with polycarbonate resin 129 and methylene chloride 1307! A charge transfer layer was formed by applying a solution dissolved in the above solution to a dry film thickness of 17 μm and drying to produce a drum-type electrophotographic photoreceptor according to the present invention. This is a copy machine (Fuji Xerox ■
It was installed in a modified model of FX-2700 manufactured by ), and an electrophotographic property test was conducted.

The results were as follows.

Charging characteristics and half-decreased exposure amount Examples 10 to 13 Polycarbonate resin (trade name Panlite L-1250 quantity Daikasei I
I) and carrier transfer substance N, N=-diphenyl-N
, N--bis(3-methylphenyl)-[1,1''-biphenyl]-4゜4' diamine and the porphyrin compound shown in the following table were blended in a maximum ratio of 10:10:1.5, and this A solution obtained by dissolving (dissolving the resin and carrier transfer substance) and dispersing (dispersing the porphyrin compound) in methylene chloride was applied and dried to produce a single-layer electrophotographic photoreceptor with a film thickness of 8 μm. An electrophotographic property test was conducted on the electrophotographic photoreceptor prepared using the above-mentioned electrostatic electrode testing device. (In this case, a voltage of +6 kV was applied to the charger.) The produced sheet-like photoreceptor was wrapped around a cylindrical aluminum pipe, mounted on the above-mentioned modified copying machine, and subjected to repeated electron transfer cycles to examine its electrical durability.The results are shown in the table below.

Cycle characteristics

[Brief explanation of the drawing]

FIG. 1 and FIG. 2 are schematic diagrams showing the structure of the electrophotographic photoreceptor of the present invention, respectively. DESCRIPTION OF SYMBOLS 1... Charge transfer layer, 2... Charge generation layer, 3... Conductive support, 4... Photosensitive layer.

Claims (1)

[Claims] (1) The following general formula (I) or (II) is applied on a conductive support.
An electrophotographic photoreceptor comprising a photosensitive layer containing a porphyrin compound represented by: ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(II) (In the formula, M is a metal atom selected from copper, cobalt, iron, nickel, zinc, and manganese, or represents a chloride of these metals, and X represents a hydrogen atom, a halogen atom, a methyl group, a nitro group, or a methoxy group)