JPS61198167A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To enhance sensitivity and to reduce residual potential after a durability test by incorporating a specified polycyclic quinone derived pigment in an electrostatic charge generating layer and a specified pyrazoline deriv. in a charge transfer layer. CONSTITUTION:The laminate type electrophotographic sensitive body is obtained by laminating on a conductive substrate the 2 layers of the charge generating layer composed essentially of a charge generating material of a polycyclic quinone deriv. represented by formula (1) and a charge transfer layer composed essentially of a charge transfer material of a pyrazoline deriv. represented by formula (2) in which R1, R2 are each alkyl, or an atomic group necessary for combining with each other and together with the adjacent N atom to form a ring, and each is optionally same or different, and X is a pyridyl or quinolyl group optionally substd. at least one alkyl or alkoxy. As the binder usable at the time of forming the charge generating layer by coating, it can be selected from the wide range of insulating resins, besides, from org. photoconductive polymers, such as poly-N-vinylcarbazole, polyvinylanthracene, and polyvinylpyrene, preferably, insulating resins, such as polyvinylbutyral and polyarylate, and it is used in an amt. of <=80wt%.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an organic photoconductor, and more particularly to an electrophotographic photoreceptor having a charge transport layer and a charge generation layer.

Conventional Contact Electrophotographic photoreceptors have been known that utilize inorganic photoconductors such as selenium, cadmium sulfide, and zinc oxide as photosensitive components.

On the other hand, since it was discovered that a 4-unit I4 compound exhibits photoconductivity, many organic photoconductors have been developed.

For example, organic photoconductive polymers such as poly-N-vinylcarbazole vinylanthracene.

Low-molecular organic photoconductors such as carbazole, anthracene, pyrazolines, oxadiazoles, hydrazones, polyaryl alkanes, phthalocyanine pigments, azo pigments, cyanine pigments, polycyclic bovine pigments, perylene pigments,
Organic pigments and dyes such as indigo dyes, thioindigo dyes, and squaric acid methine dyes are known.

In particular, organic pigments and dyes that affect photoconductivity are easier to synthesize than inorganic materials, and the variety of compounds that exhibit photoconductivity in an appropriate wavelength range has been expanded. Photoconductive organic pigments and dyes have been proposed.

For example, US Patent No. 4123270, US Patent No. 424761
No. 4, No. 4251613, No. 4251614,
Same No. 4256821, Same No. 4260672, Same No. 4
No. 268596, No. 4278747, No. 4293
628, an electrophotographic photoreceptor using a photoconductive disazo pigment as a charge generation substance in a photosensitive layer functionally separated into a charge generation layer and a charge transport layer is known.

An electrophotographic photoreceptor using such an organic photoconductor can be produced in one coat by appropriately selecting a binder, so it is possible to provide an extremely highly productive and inexpensive photoreceptor.
Moreover, it has the advantage of being able to freely control the sensitive wavelength range by selecting the organic pigment.

A multilayer photoreceptor obtained by laminating a charge transport layer and a charge generation layer mainly composed of a charge generation material has a higher sensitivity and hR of residual potential after durability tests than other single layer photoreceptors.
1st place is an advantage, but it is still not at a sufficient level.

Problems to be Solved by the Invention An object of the present invention is to provide a laminated electrophotographic photoreceptor having high sensitivity and extremely low residual potential even after a durability test, by improving the drawbacks listed in 1-.

Means and Action for Solving the Problems The object of the present invention is to provide a conductive support with a charge generation layer containing a charge generation material as a main component and a charge transport layer containing a charge transport material as a main component. In a laminated electrophotographic photoreceptor having layers, a polycyclic quinone pigment of structural formula (1) is used in the charge generation layer, and a pyrazoline compound represented by general formula (2) is used in the charge transport layer. achieved.

A pyrazoline compound or the like used in the charge transport layer can be added to the charge generation layer, and the effect becomes even more remarkable.

Also, is the charge generation layer used in the present invention a single layer or a layer containing a mixture of a charge generation material and a charge transport material? It can also be used as an li layer.

The present invention provides a laminated electrophotographic photoreceptor in which a charge generation layer and a charge transport layer are provided on a conductive support, in which the charge generation layer comprises a layer containing a polycyclic bovine non-based pigment represented by structural formula (1). ,
The charge transport layer is a pyrazoline compound represented by the general formula (2) (wherein R1 and Rx are residues that form a ring together with an alkyl group or a nitrogen atom, and R1 and R are the same or different). X is an unsubstituted pyridyl group, quinolyl group, or a pyridyl group or quinolyl group substituted with at least one alkyl group or alkoxyno, !; Consists of an electrophotographic photoreceptor.

Representative compounds of the pyrazoline compound represented by the general formula (2) used in the present invention are illustrated below.

In the laminated electrophotographic photoreceptor of the present invention, the charge generation layer contains as much of the charge generation material listed in I as possible in order to obtain sufficient absorbance, and efficiently transfers the generated charge carriers to the charge transport layer. For implantation, a thin film layer 1, e.g.
It is preferable that the thin film layer has a thickness of 0IL or less, preferably 0.01 to 1IL.

This means that most of the incident light is absorbed by the charge generation layer, generating many charge carriers, and that the generated charge carriers are injected into the charge transport layer without being deactivated by recombination or trapping. This is due to the need to do so.

The charge generation layer can be formed by #T-coating the polycyclic bovine non-based pigment and, if necessary, a charge transporting material together with a suitable binder (or without a binder) on the substrate.
It can also be obtained by forming a leather coating using a vacuum leather coating device.

1;: Luggage 7t: When adding a charge transporting material to the layer, the pyrazoline compound is 10 times or less (heavy/noise ratio), preferably 0.01 to 1 times (amount ratio), the charge generating material in terms of box%. be.

The binder that can be used to form the charged material layer by coating can be selected from a wide variety of insulating resins, as well as organic photoconductive polymers such as poly-N-vinylcarbazole, polyvinylanthracene, and polyvinylpyrene. .

Preferably, polyvinyl butyral, polyarylate (
m-polymer of bisphenol A and phthalic acid, etc.), polycarbonate, polyester, phenoxy resin, polyvinyl acetate, acrylic resin, polyacrylamide, polyamide, polyvinylpyridine, cellulose resin, urethane resin, epoxy resin, zein, polyvinyl alcohol,
Insulating resins such as polyvinylpyrrolidone can be mentioned.

The resin contained in the charge generation layer is suitably 80% by weight or less, preferably 40% by weight or less.

The solvent that dissolves these resins varies depending on the type of resin, and is preferably selected from those that do not dissolve the underlying charge transport layer or subbing layer.

Examples of organic solvents include alcohols such as methanol, ethanol, and impropanol, ketones such as acetone, methyl ethyl ketone, and cyclohexanone, N,
N-dimethylformamide, N.

Amides such as N-dimethylacetamide, sulfoxides such as dimethyl sulfoxide, ethers such as tetrahydrofuran, dioxane, ethylene glycol monomethyl ether, esters such as methyl acetate, ethyl acetate, chloroform, methylene chloride, dichloroethylene, Aliphatic halogenated hydrocarbons such as carbon chloride and trichloroethylene, or aromatics such as benzene, toluene, xylene, ligroin, monochlorobenzene and dichlorobenzene, etc. can be used.

Coating methods include dip coating, spray coating, spinner coating, bead coating,
This can be carried out using a coating method such as a Mayer bar coating method, a blade coating method, a roller coating method, or a curtain coating method.

For drying, it is preferable to dry to the touch at room temperature and then heat dry.

Heat drying can be carried out at a temperature of 30 to 200° C. for 5 minutes to 2 minutes, either still or with air blowing.

The charge transport layer is electrically connected to the charge generation layer described above, and has the function of receiving and receiving charge carriers injected from the charge generation layer in the presence of an electric field, and transporting these charge carriers to the surface. have.

At this time, this charge transport layer may be laminated on the A of the charge generation layer, or may be laminated on the F of the charge generation layer.

However, it is preferable that the charge transport layer is laminated on the charge generation layer L.

The substance that transports charge carriers in the charge transport layer (hereinafter referred to as charge transport material) is preferably substantially insensitive to the wavelength range of magnetic waves to which the charge generation layer described above is sensitive. .

The term "electromagnetic waves J" as used herein includes a broad definition of "light rays" including γ-rays, X-rays, ultraviolet rays, visible light, near-infrared rays, infrared rays, far-infrared rays, and the like.

When the photosensitive wavelength range of the charge transport layer coincides with or overlaps that of the charge generation layer, charge carriers generated in both will capture each other, resulting in a decrease in sensitivity.

When the charge transport material does not have a film formed on it.

A film can be formed by selecting an AB binder.

Examples of resins that can be used as binders include acrylic resins, polyarylates, and polyesters.

Polycarbonate, polystyrene, acrylonitrile
Styrene copolymer, acrylonitrile-butadiene copolymer, polyvinyl butyral.

Polyvinyl formal, polysulfone, polyacrylamide, polyamide, 11X! Insulating resin such as rubber, or poly-N-vinylcarbazole.

Organic photoconductive polymers such as polyvinylanthracene and polyvinylpyrene may be mentioned.

Since the charge transport layer has a limit in its ability to transport charge carriers, it cannot be made thicker than necessary.

- Generally 5 to 30g, but the preferred range is 8 to 30g
There are 20 pots.

When forming the charge transport layer using four layers, the 11 mm coating method described in 1-1 can be used.

A photosensitive layer having such a laminated structure of a charge generation layer and a charge transport layer is provided on a substrate having a conductive layer.

As the substrate having a conductive layer, it is possible to use a material whose substrate itself is conductive, such as aluminum, aluminum alloy, copper, lead oxide, stainless steel, vanadium, molybdenum, chromium, titanium, nickel, indium, gold, platinum, etc. In addition, aluminum, aluminum alloy,
Plastics (e.g., polyethylene, polypropylene) having a layer formed of indium oxide, tin oxide, indium oxide-tin oxide alloy, etc. by the vacuum 75 deposition method.

Polyvinyl chloride, polyethylene terephthalate, acrylic resin, polyethylene fluoride, etc.), conductive particles (e.g. carbon black, silver particles W) are coated on plastic H with a suitable binder, A substrate impregnated with paper or a plastic material containing a conductive polymer can be used.

A subbing layer having barrier and adhesive functions can also be provided between the conductive layer and the photosensitive layer.

- The first layer of the bow is made of casein, polyvinyl alcohol trocellulose, ethylene-acrylic acid copolymer, polyvinyl butyral, phenolic resin, polyamide (nylon 6).
, nylon 66, nylon 610, JI"ift" synthetic nylon, alkoxymethylated nylon, etc.), polyurethane gelatin, aluminum oxide, and the like.

The thickness of the subbing layer is 0.1 to 40 g, preferably o. i~
Three pots is appropriate.

When using a photoreceptor in which a conductive layer, a charge generation layer, and a -I5 charge transport layer are laminated in this order, and the charge transport material is made of an electron transport material, it is necessary to charge the surface of the charge transport layer first. When exposed to light after being charged, electrons generated in the charge generation layer are injected into the charge transport layer in the exposed area, and then reach the surface and neutralize the static charge, resulting in attenuation of the surface potential and an electrostatic contrast between it and the unexposed area. occurs.

A visible image is obtained by developing the electrostatic latent image thus formed with a negatively charged toner.

This can be directly fixed, or the toner image can be transferred to paper, plastic film, etc. and then developed and fixed.

Alternatively, a method may be used in which the electrostatic latent image on the photoreceptor is transferred onto an insulating layer of transfer paper, then developed and fixed.

The type of developer, the developing method, and the fixing method may be any known ones or known methods, and are not limited to specific ones or methods.

On the other hand, when the charge transport material is a hole transport material, it is necessary to charge the surface of the charge transport layer negatively, and when exposed to light after charging, the genuine tag generated in the charge generation layer is injected into the charge transport layer in the exposed area. After that, it reaches the surface and neutralizes the negative charges, resulting in a decrease in surface potential and an electrostatic contrast between the surface potential and the unexposed area.

During development, it is necessary to use a positively charged toner, contrary to the case where an electron transport material is used.

The electrophotographic photoreceptor used in the present invention is subject to deterioration due to ultraviolet rays, ozone, etc., dirt due to oil, etc., scratches due to metal chips, etc., damage to the photoreceptor due to photoreceptor contact members such as developing members, transfer members, cleaning members, etc. A protective layer may be further provided on the charge generation layer for the purpose of preventing scratching.

In order to form an electrostatic latent image on this protective layer H.

It is preferable that the surface resistivity is 10//Ω or less.

The protective layer used in the present invention is made of polyvinyl butyral, polyester, polycarbonate, acrylic resin, methacrylic resin, nylon, polyimide, polyarylate, polyurethane, styrene-butadiene covol, styrene-
It can be formed by applying a solution prepared by dissolving a resin such as an acrylic acid copolymer or a styrene-acrylonitrile copolymer in a suitable organic solvent onto the photosensitive layer and drying it.

Additionally, additives such as ultraviolet absorbers may be added to the resin liquid.

The thickness of the protective layer is generally 0.05 to 20! , preferably in the range of 0.2 to 5 pots.

Example 1 An ammonia aqueous solution of casein (2 g of casein 11, 1 g of 28% ammonia water,
Apply 222ml of water by dip coating method, dry and apply TB1. A subbing layer of Og/Maro was formed.

Next, 1 part of the charge-generating material of the configuration (1), 1 part of butyral resin (Eslec BM-2, manufactured by Sekisui Chemical Co., Ltd.), and 30 parts by weight of isopropyl alcohol were dispersed in 4 parts using a ball mill dispersion machine. .

This dispersion was applied to the previously formed subbing layer H by a dip coating method and dried to form a charge generation layer.

The film thickness was 0.3 uL.

Next, 1 part of the above-mentioned pyrazoline compound example (1), 1 part of polysulfone (P1700, manufactured by Union Carbide), and 6 parts of monochlorobenzene were mixed and dissolved by stirring with a stirrer.

This liquid was applied to the charge generation layer by dip coating and dried to form a charge transport layer.

This film thickness was 12 pots.

A corona discharge of 15 KV was applied to the photoreceptor thus prepared.

The surface potential (initial potential v) at this time was measured.

Furthermore, the surface potential of this photoreceptor was measured after it was left in a dark place for 5 seconds (dark decay Vr). , 5ec).

These results were as follows.

V: -570V, Vr: -555V, E1
/2:3, 8 1ux, sec Examples 2 to 10 Examples 2 to 10 except that pyrazoline compound examples (2) to (lO) were used in place of pyrazoline compound example (1) used in Example 1, respectively. Create a photoreceptor in exactly the same way as 1.
The characteristics of this photoreceptor were measured.

These results are shown in Table 1.

Table 1 1 member 1 Kaidai d Hungryuan-V) VJ (Go) Mue' L Yuo) 2 (:?) 580585 4.43 (
3) 575555 3.7 4 (4) 5755130 3.85 (5)
5ft5550 4.0 e (8) 57055s 4.1? (7)
575555 3.8 8 (8) 590575 4.4 9 (9) 595580 4.2 10 (10) Boo 590 4.5 Comparative Example 1
~6 The following Table 2 was used instead of the pyrazoline compound used in Example 1.
Photoreceptors of Comparative Examples 1 to 6 were prepared using the charge transport materials (1) to (6) shown in Table 1, but in the same manner as above.

Table 2 亙Meng substance Me, structural formula Table 3 shows the charging characteristics of the photoreceptor shown in item 1-.

Table 3 1 (1) 550 500 5.42 (2
) 530 495 5.03 (3) 5
00 485 5.74 (4) 560 515 7
．． 1 5 (5) 580 5sOe, 2e (8)
570 580 B! As is clear from the results below, it can be seen that the laminated photoreceptor of the present invention has extremely high sensitivity compared to the photoreceptors of Comparative Examples 1 to 6.

Furthermore, the photoreceptors of Examples 1 to 3 were used as NP manufactured by Canon Co., Ltd.
One image was produced 20,000 times using a -1502 copying machine.

As a result, good quality images were obtained even after repeating the test 20,000 times with each photoreceptor, indicating that the photoreceptor of the present invention has extremely excellent durability.

Claims (1)

[Claims] (1) In a laminated electrophotographic photoreceptor in which a charge generation layer and a charge transport layer are provided on a conductive support, the charge generation layer is a polycyclic quinone pigment having the structural formula (1) ▲ Numerical formula, chemical formula, table, etc. ▼ A pyrazoline compound whose charge transport layer is represented by the general formula (2) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (2) (In the formula, R_1 and R_2 are an alkyl group or a nitrogen atom R_1 and R_2 are residues that together form a ring, and may be the same or different. X is an unsubstituted pyridyl group, a quinolyl group, or a pyridyl group substituted with at least one alkyl group or alkoxy group. , a quinolyl group).