JP3141160B2 - Photoconductor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photosensitive member. In particular, it relates to a negatively charged photoreceptor.

[0002]

BACKGROUND OF THE INVENTION Since the development of electrophotography, the range of studies on photoconductive materials used for photoconductors has been expanded to organic photoconductors (OPC) using inorganic to organic photoconductive materials (PCM). Further, the photoconductive functions of carrier generation and carrier transport are separated into a carrier generating substance (CGM) and a carrier transporting substance (CTM), respectively, and the photoconductive layer (photosensitive layer; P
The layer configuration of (CL) has also been improved from the analysis of the carrier behavior, and the improvement or development of binder resins used for layer formation has been actively conducted.

[0003] With the improvement of these technologies, since the preparable paper can be used as a transfer material, the electrophotographic copying method is immediately generalized, suitable for mass use, improved in performance, durable,
Improvements in running costs, especially in consideration of comprehensive aspects such as environmental hygiene during use, have been required.

Various organic substances have been developed as CGMs for use in the PCM in response to such circumstances. However, photoconductors having higher sensitivity, higher durability, and higher image quality are required. I have. However, improving sensitivity, durability, and image quality often conflict with each other, and satisfactory results have not yet been obtained.

Various azo pigments have been disclosed as CGM used in photoreceptors. These have relatively high sensitivity, but have the disadvantage that the charging characteristics, especially the rising characteristics of the charging, are deteriorated by repeated use and the potential is likely to be lowered.
In addition, azo pigments are easily affected by changes in light, ozone, temperature and humidity, and it is difficult to obtain stable characteristics. In particular, in the case of negative charging, the amount of ozone generated from the band electrode is about seven times larger than that of positive charging, and ozone resistance is important.

It is also disclosed that a polycyclic quinone compound is used as CGM. Although this substance is relatively stable to ozone, it is insufficient in sensitivity.

On the other hand, Japanese Patent Publication No. 61-8423 and Japanese Patent Application Laid-Open No. 59-59686 disclose that perylene compounds can be used as CGM.
Nos. 63-180955, 63-180956 and 63-291061. This compound is characterized by being highly sensitive and chemically stable. However, it was difficult to obtain the dispersion stability of the coating liquid, so that high image quality could not be obtained. Further, when used in a negatively charged photoreceptor having a laminated structure, if the durability of the charge transport layer combined with the CGM is insufficient even if it is chemically stable, the stability of the perylene compound cannot be utilized. .

[0008]

The objects of the present invention are as follows: (1) It has high spectral sensitivity to a long wavelength region, high image quality,
(2) It does not cause a decrease in the charging potential and an increase in the blank paper potential when used repeatedly. (3) It is chemically resistant to O ₃ , NO _X or ultraviolet rays. (4) It is a mechanical film when used repeatedly. It is an object of the present invention to provide a negatively charged photoreceptor having a small thickness loss and few flaws.

[0009]

The object of the present invention is to provide a photoconductor in which a charge transport layer (CTL) is laminated on a charge generation layer (CGL), wherein the CGL has the following general formula (BIP-1) or (B
Containing at least one resin of a perylene derivative represented by IP-2), a butyral resin, and a silicone resin;
And the following general formula in CTL (BPA-2), ( BPZ
-1), shown (polymer of the compound represented by BPZ-2), or mixtures of these polymers, or by the general formula
This is achieved by a negatively charged photoreceptor characterized in that it contains at least one copolymer of the compound to be prepared .

As the perylene derivative according to the present invention, a compound represented by the following general formula (BIP-1) or (BIP-2) is used.

[0011]

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In the formula, Z represents an atom group necessary for forming a substituted or unsubstituted aromatic ring.

Preferred examples of Z include a benzene ring,
Examples include a naphthalene ring, an anthracene ring, a phenanthrene ring, a pyridine ring, a pyrimidine ring, a pyrazole ring and an anthraquinone ring, and particularly preferred are a benzene ring and a naphthalene ring.

As the substituent for Z, alkyl, alkoxy, aryl, aryloxy, acyl, acyloxy,
Amino, carbamoyl, halogen, nitro, cyano and the like can be mentioned.

These derivatives have a Bragg angle 2θ of 6.3 ゜ ± 0.3 in the X-ray diffraction spectrum for Cu-Kα radiation.
Those having peaks at 2 °, 12.5 ° ± 0.2 °, 25.4 ° ± 0.2 °, and 27.0 ° ± 0.2 ° are preferred.

Z of the specific compounds A-1 to A-21 of the perylene derivative (BIP) is shown.

[0017]

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[0018]

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Formula (BIP-1) or (BIP-
The compound represented by 2) is obtained according to the reaction formula (1).
It can be easily synthesized.

[0020]

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Further, the butyral resin of the binder resin of CGL according to the embodiment of the present invention is preferably polyvinyl butyral represented by the following general formula (PVB).

[0022]

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In the formula, R represents a hydrogen atom, a methyl group or an ethyl group. A, b, s, and h represent the degree of polymerization.

In general, the physical and chemical properties of polyvinyl butyral vary depending on its composition, and the mechanical properties and solution viscosity vary depending on the degree of polymerization.

The polyvinyl butyral used for the binder of CGL according to the present invention is obtained by saponifying polyvinyl acetate resin,
A polyvinyl alcohol resin which leaves a vinyl acetate moiety (a structural unit having a polymerization degree index s in the general formula (PVB)) is produced, and conditions for leaving a vinyl alcohol structural unit having a polymerization degree index h are selected. A copolymer resin having an acetalized structural unit having a polymerization degree index a with at least one of propyl aldehyde and a butyralized structural unit having a polymerization degree index b with butyl aldehyde; Is preferably 50 mol% or more, and (a + b) is 50 mol%
The above is preferred. In addition, the degree of polymerization must be 1000 or more. The upper limit is 10,000 or less, preferably 5,000 or less.

The silicone resin according to the present invention is an organopolysiloxane having a structural unit represented by the following general formula (SI).

[0027]

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The silicone resin has a long chain structure and a complex crosslinked structure. From the viewpoint of raw material production technology, R in the general formula (SI) is preferably a methyl group or a phenyl group.

Further, in addition to the simple straight silicone resin having only the above-mentioned structural unit, a modified silicone resin copolymerized with another structural unit can be used. It can be applied as a functional polymer.

There are already many commercially available straight silicones and modified silicone resins, and there is a wide range of choices.

The polycarbonate used in the CTL of the present invention includes a BPZ type polycarbonate represented by the general formula (BPZ-1) and a di represented by the general formula (BPZ-2).
Me-BPA type polycarbonate, a general formula (BPA-
The diMe-BPZ type polycarbonate shown in 2) or a mixture or copolymer thereof is used.

[0032]

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In the present invention, by using the BIP, a high sensitivity can be obtained because the absolute value of the spectral sensitivity is high and the spectral sensitivity extends to a long wavelength region.

The use of BIP, butyral, and silicone makes CGL chemically and electrically stable.

In addition, BPZ, diMe-BPZ, diMe-B
By using PA, the mechanical strength is increased, and a photoreceptor with less flaws and wear is obtained. Further, since these binders have a smaller ozone transmittance than BPA which has been conventionally used, the deterioration of CTM by ozone is reduced and the binder becomes chemically stable.

By the above synergistic effect, a highly durable photoreceptor can be obtained mechanically, chemically and electrically.

Further, by combining BIP with butyral and silicone, CGM is uniformly and finely dispersed, and an image having no image unevenness and a high resolution can be obtained. In addition, since the dispersion stability of the CGL coating liquid is good, the liquid life is prolonged and a stable quality liquid can be produced. There is no particular limitation on the CTM that can be used in the present invention. Compound,
Hydrazine compounds, pyrazoline compounds, amine derivatives,
Oxazolone derivatives, benzothiazole derivatives, benzimidazole derivatives, quinazoline derivatives, benzofuran derivatives, acridine derivatives, phenazine derivatives, aminostilbene derivatives, poly-N-vinylcarbazole, poly-
1-vinylpyrene, poly-9-vinylanthracene and the like. As the CTM used in the present invention, a CTM which has an excellent ability to transport holes generated at the time of light irradiation to the support and which is suitable for combination with the BIP of the present invention is used.

The negatively charged photoreceptor of the present invention comprises, for example,
As shown in FIG. 4, on a support 1 (a conductive support or a sheet provided with a conductive layer), CGL2 is a lower layer,
A PCL having a laminated structure with CTL3 as an upper layer is provided.

In the laminated structure, most of the incident light amount is CG
L is absorbed by L to generate many charge generating carriers, and the generated charge carriers are injected into the CTL without being deactivated by recombination or trapping. It is preferable to form a thin film layer as much as possible within the range.

The CTL is electrically connected to the above-described CGL, and has a function of transporting charge carriers injected from the CGL to the surface in the presence of an electric field.

A protective layer may be provided on the PCL.
Further, an undercoat layer (intermediate layer) having a barrier function and adhesiveness may be provided between the support and the PCL.

If necessary, CTM may be added to the CGL of the present invention. Laminated function separation type C
The thickness of the GL is preferably 0.05 to 5 μm. Also C
The thickness of the TL is preferably 10 to 60 μm.

The thickness of the surface protective layer is preferably 0.1 to 7 μm, and the thickness of the intermediate layer is preferably 0.05 to 10 μm.

Examples of the layer structure of the photoreceptor of the present invention are shown in FIGS. In the figure, 1 is a support, 2 is CGL, 3
Is CTL. 5 is a protective layer, 4 is a barrier function,
It is an intermediate layer for improving adhesion.

Examples of the binder resin usable for the protective layer and the intermediate layer include polystyrene, polyethylene, polypropylene, acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, polyvinyl butyral resin, epoxy resin, polyurethane resin, and phenol resin. , Polyester resin, alkyd resin, polycarbonate resin, silicone resin, melamine resin, etc., addition polymerization type resin, polyaddition type resin, polycondensation type other resin, and copolymer containing two or more of repeating units of these resins Coalescing resin,
For example, in addition to an insulating resin such as a vinyl chloride-vinyl acetate-maleic anhydride copolymer resin, a high molecular organic semiconductor such as poly-N-vinyl carbazole may be used.

In the PCL of the present invention, an antioxidant can be added for the purpose of preventing ozone deterioration.

Representative examples of such antioxidants are shown below, but are not limited thereto.

Group (1): hindered phenols dibutylhydroxytoluene, 2,2'-methylenebis (6-
t-butyl-4-methylphenol), 4,4'-butylidenebis (6-t-butyl-3-methylphenol), 4,4'-thiobis (6-t-butyl-3-methylphenol), 2, 2'-butylidenebis (6-t-butyl-4-methylphenol), α-tocophenol, β-tocophenol, 2,2,4-trimethyl-6-
Hydroxy-7-t-butylchroman, pentaerythyltetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], 1,6-hexanediol-bis [3-
(3,5-di-t-butyl-4-hydroxyphenyl) propionate], butylhydroxyanisole, dibutylhydroxyanisole, 1- [2-｛(3,5-di-tert-butyl-4-hydroxyphenyl) propionyl Oxydiethyl] -4-
[3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyloxy] -2,2,6,6-tetramethylpiperidyl and the like.

Group (2): paraphenylenediamines N-phenyl-N'-isopropyl-p-phenylenediamine,
N, N'-di-sec-butyl-p-phenylenediamine, N-phenyl-N-sec-butyl-p-phenylenediamine, N, N'-dimethyl-N, N'-di-t-butyl-p -Phenylenediamine.

Group (3): hydroquinones 2,5-di-t-octylhydroquinone, 2,6-didodecylhydroquinone, 2-dodecylhydroquinone, 2-dodecyl
-5-chlorohydroquinone, 2-t-octyl-5-methylhydroquinone, 2- (2-octadecenyl) -5-methylhydroquinone and the like.

Group (4): Organic phosphorus compounds dilauryl-3,3'-thiodipropionate, distearyl-3-3'-thiodipropionate, ditetradecyl-3,
3'-thiodipropionate and the like.

These compounds are known as antioxidants for rubber, plastics, oils and the like, and commercially available products can be easily obtained.

These antioxidants may be added to any of CGL, CTL, and the protective layer. In this case, the amount of the antioxidant added is 0.1 to 100% by weight, preferably 1 to 50% by weight, particularly preferably 5 to 25% based on 100% by weight of CTM.
Weight.

Next, as the conductive support for supporting the PCL, a metal plate such as aluminum or nickel, a metal drum or a metal foil is laminated, or
A plastic film on which tin oxide, indium oxide, or the like is deposited, or a film or drum of paper or plastic coated with a conductive substance can be used.

In the present invention, PCL is the aforementioned CGM,
A dispersion obtained by dispersing each CTM together with a binder resin containing at least the binder according to the present invention in an appropriate dispersion medium or solvent, for example, dip coating, spray coating,
It can be provided by a method of coating and drying on a support or an undercoat layer or CTL or CGL by blade coating, roll coating or the like.

The perylene derivative of the present invention can be dispersed in a dispersion medium after being crushed into fine particles having an appropriate particle size using, for example, a ball mill or a sand mill. For the dispersion treatment, a ball mill, a homomixer, a sand mill, an ultrasonic disperser, an attritor, or the like is used.

The dispersion medium used in the present invention includes, for example, hydrocarbons such as hexane, benzene, toluene and xylene; methylene chloride, methylene bromide, 1,2-
Halogenated hydrocarbons such as dichloroethane, sym-tetrachloroethane, cis-1,2-dichloroethane, 1,1,2-trichloroethane, 1,2-dichloropropane, chloroform, bromoform, chlorobenzene; acetone, methyl ethyl ketone, cyclohexanone Ketones such as ethyl acetate, butyl acetate and the like: alcohols such as methanol, ethanol, propanol, butanol, cyclohexanol, heptanol, ethylene glycol, methyl cellosolve, ethyl cellosolve, cellosolve acetate and derivatives thereof; tetrahydrofuran , 1,4-dioxane, furan, furfural ethers and acetals; pyridine, butylamine, diethylamine, ethylenediamine, isopropanolamine and other amines; N, N-dimethylformamide and other amides and the like Containing compound, other fatty acids and phenols, sulfur, such as carbon disulfide and triethyl phosphate may be used alone or in combination of two or more of such phosphorus compounds.

In the present invention, one or more electron accepting substances can be contained in CGL for the purpose of improving sensitivity, reducing residual potential and reducing fatigue during repeated use.

Examples of the electron-accepting substance that can be used here include succinic anhydride, maleic anhydride, dibromo anhydride, maleic acid, phthalic anhydride, tetrachlorophthalic anhydride, tetrabromophthalic anhydride, and 3-nitroanhydride. Phthalic acid, 4-nitrophthalic anhydride, pyromellitic anhydride, melitic anhydride, tetracyanoethylene, tetracyanoquinodimethane, o-dinitrobenzene, m-dinitrobenzene, 1,3,5-trinitrobenzene, para Nitrobenzene, picryl clyde, quinone chlorimide, chloralyl, bulmanil, dichlorodicyanoparabenzonone, anthraquinone, dinitroanothraquinone, 2,7-dinitrofluorenone, 2,4,7-trinitrofluorenone, 9-fluorenylidene [dicyanolidene Methylene malonodinitrile],
Polynitro-9-fluorenidene- [dicyanomethylenemalonodinitrile], picric acid, 0-nitrobenzoic acid, p-nitrobenzoic acid, 3,5-dinitrobenzoic acid, pentafluorobenzoic acid, 5-nitrosalicylic acid, 3,5 -Dinitrosalicylic acid, phthalic acid, melitic acid and other compounds having a high electron affinity. Further, the addition ratio of the electron accepting substance is such that the perylene derivative of the present invention: electron accepting substance = 100: 0.01 to 200, preferably 100: 0.1 to 10 by weight ratio.
It is 0.

This electron accepting substance may be added to CTL. The ratio of addition of the electron accepting substance to such a layer is, in weight ratio, total CTM: electron accepting substance = 100: 0.01 to 100, preferably
100: 0.1 to 50.

The photoreceptor of the present invention may further contain, if necessary, an ultraviolet absorber or a dye for correcting color sensitivity for the purpose of protecting PCL.

The electrophotographic photoreceptor containing the perylene derivative of the present invention can favorably respond to visible light and near-infrared light, and has a preferable absorption maximum in a wavelength range of about 400 to 700 μm.

As a light source adapted to such a wavelength, a halogen lamp, a fluorescent lamp, a tungsten lamp or the like is generally used.

[0064]

Example 1 An Al drum having a diameter of 80 mm was used as a substrate.

As a CGM, 2 parts by weight of BIP (A-1) and 1 part by weight of a polyvinyl butyral resin Esrec BX-1 (manufactured by Sekisui Chemical) as a binder were added to 100 parts by weight of 2-butanone, and the mixture was subjected to a sand grinder for 20 hours. Dispersion was performed to obtain a CGL coating liquid. This solution was dip-coated on an Al substrate to form a CGL having a thickness of 0.5 μm.

A stilbene compound having the following structural formula as CTM:

[0067]

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Compound C-1; BPZ type polycarbonate resin having 15 parts by weight and a general formula (BPZ-1) as a binder; 20 parts by weight of Iupilon Z-200 (manufactured by Mitsubishi Kagaku Chemical) with 1,2-dichloroethane 100 Dissolve in parts by weight and CTL
A coating liquid was obtained. This coating solution was applied onto the CGL by dip coating.
Drying was carried out at 0 ° C. for 30 minutes to obtain a negatively charged electrophotographic photosensitive member having a thickness of 20 μm.

Examples 2 to 8 Electrophotographic photosensitive members of the present invention were obtained in the same manner as in Example 1 except that the combinations of CGM and binder were changed as shown in Table 1.

The C used in Examples 5, 6, 7 and 8
The binder resin of GL is silicone resin KR-5240 (manufactured by Shin-Etsu Chemical).

Comparative Examples (1) to (5) Photosensitive members of comparative examples were obtained in the same manner as in Example 1 except that the following combinations of comparative CGM and binder were changed as shown in Table 1. The CGM binder of Comparative Example (4) and the CTL binder of Comparative Example (5) are acrylic resin BR-80 (manufactured by Mitsubishi Rayon).

[0072]

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The photoreceptor thus obtained was mounted on a Konica copier U-Bix2025, and a 100,000 copy actual photographing test was performed. Table 2 shows changes in the characteristics of the photoreceptor and changes in the image quality.

[0074]

[Table 1]

[0075]

[Table 2]

As is clear from Table 2, the samples of the examples of the present invention have good practicability in the initial stage and in repeated use in chargeability, sensitivity, image quality and film thickness loss, but in the comparative examples, Most of the evaluation performance has a problem in practicality.

[0077]

As described in the present invention, the CGL prepared by dispersing the perylene derivative selected in the present invention at least in a binder containing butyral or a silicone resin and using the binder containing the polycarbonate selected in the present invention in a CGL.
By laminating the TL, it is possible to obtain a negatively charged photoreceptor exhibiting good performance in initial and repeated use in electrophotographic properties and physical properties.

[Brief description of the drawings]

FIG. 1 is a sectional view of an example of a photoreceptor having an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Support body 2 ... Carrier generation layer 3 ... Carrier transport layer 4 ... Intermediate layer 5 ... Protective layer

 ──────────────────────────────────────────────────の Continuing from the front page Judge of the colleague Judge Takanashi Judge Miyako Kaneo Judge Jichi Rokka (56) Reference JP-A-63-180956 (JP, A) JP-A-3-24059 (JP, A) JP-A-2-25464 (JP, A) JP-A-62-242951 (JP, A) JP-A-2-256057 (JP, A) JP-A-5-6014 (JP, A)

Claims (1)

(57) [Claims] 1. A photoreceptor having a charge transport layer laminated on a charge generation layer, wherein the charge generation layer has the following general formula (BIP-
1) or a perylene derivative represented by (BIP-2) and at least one resin selected from the group consisting of a butyral resin and a silicone resin, and the charge transport layer has the following general formula (BP)
A-2), (BPZ-1) and (BPZ-2)
A negatively charged photoconductor comprising at least one of a polymer of a compound , a mixture of these polymers, and a copolymer of a compound represented by the above general formula . Embedded image (Z in the formula represents an atomic group necessary for forming a substituted or unsubstituted aromatic ring. N represents a positive integer.)