JPH01267555A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain an electrophotographic sensitive body superior in sensitivity also in the short wavelength region and to prevent accumulation of residual potential and deterioration of electrification and superior in durability by incorporating a specified compound in an interlayer. CONSTITUTION:The interlayer contains at least one of the compounds represented by formulae I, II, and III in which each of R1, R2, and R4 is H, lower alkyl, alkoxy, or halogen; R3 is H or OH; each of R5 and R6 is H, -SO3H, its metal salt, -COOH, its metal salt, lower alkyl, alkoxy, halogen, or OH; each of R7-R10 is H, lower alkyl, alkoxy, or halogen, thus permitting sensitivity also in the short wavelength region and durability to be superior and accumulation of residual potential and deterioration of electrification to be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to improvements in electrophotographic photoreceptors, particularly positively charged electrophotographic photoreceptors.

[Prior art]

2. Description of the Related Art Electrophotographic photoreceptors have been known that are provided with a charge generation layer containing a charge generation substance and various resins.

Examples of this include polyvinyl butyral (Japanese Patent Application Laid-open No. 58-105154), fatty acid cellulose ester (
JP-A No. 58-166353), acrylic resin with Tg of 70°C or less and an acid value of 10 to 40 (JP-A No. 58-1920)
No. 40), a mixture of a resin with a Tg of 70°C or less and a resin with a Tg of 75°C or more (JP-A-58-193549), a resin with lower compatibility in the charge-generating substance-resin-solvent system. -Re-dispersed by adding a solvent system (JP-A-56-1
No. 2646).

Polyvinylpyrrolidone (JP-A-56-113140)
, polyvinyl formal resin (JP-A-61-23584
Examples include those using resins such as No. 4).

However, conventionally known photoreceptors have a problem in that the sensitivity and chargeability against pre-exposure fatigue vary depending on the mixing ratio of the charge generating substance and the binder resin.

In other words, in conventional photoreceptors, sensitivity can be increased by reducing the amount of binder resin used for the charge-generating substance, but the chargeability deteriorates significantly due to pre-exposure fatigue, and conversely, the use of binder resin for the charge-generating substance If the amount is increased, it is possible to suppress a decrease in chargeability due to pre-exposure fatigue, but this includes the problem of a significant decrease in sensitivity.

Furthermore, in recent years, organic photoreceptors, particularly negatively charged photoreceptors in which a charge generation layer and a charge transfer layer are successively laminated on a support, have been widely used. This photoreceptor generates more ozone than the positively charged type, and therefore the surface of the photoreceptor is susceptible to chemical changes, resulting in blurred images and increased residual potential.

In addition, light yellow to light yellow compounds such as hydrazone compounds, pyrazoline compounds, oxazole compounds, and styryl compounds are used in the charge transfer layer.
Since a yellow hole transfer material is used, short wavelength light, such as blue light of 500 nm or less, is absorbed by this charge transfer layer, and such a photoreceptor has the disadvantage of extremely weak sensitivity in the short wavelength range. . This decrease in sensitivity is significant for blue light, and therefore the light attenuation effect cannot be achieved unless the amount of light is increased. However, increasing the amount of light in this manner causes a problem in that fatigue accumulates on the photoreceptor and its durability decreases.

On the other hand, in a positively charged photoreceptor in which a charge transfer layer and a charge generation layer are laminated in that order, the charge generation layer becomes the surface layer, and the surface layer wears out due to repeated processes of charging, exposure, development, transfer, and cleaning. and its durability decreases.

As a method to eliminate these drawbacks, a method of increasing the thickness of the charge generation layer has been proposed (Japanese Patent Application Laid-Open No. 59/22).
4846, JP-A-59-174849), this method has the disadvantage that residual potential accumulates due to carrier traps in the charge generation layer and charging properties deteriorate.

〔the purpose〕

SUMMARY OF THE INVENTION An object of the present invention is to provide an electrophotographic photoreceptor that exhibits excellent sensitivity even in the short wavelength range, does not accumulate residual potential or deteriorate charging performance, and has excellent durability.

〔composition〕

According to the present invention, in an electrophotographic photoreceptor in which a charge transfer layer, a charge generation layer, an intermediate M, and a protective layer are sequentially provided on a conductive support, the intermediate layer has the following general formulas (I) to ( VI
There is provided an electrophotographic photoreceptor characterized by containing at least one of the compounds represented by II).

(RxJz+R4: hydrogen, lower alkyl group, alkoxy group, halogen R1: hydrogen, hydroxyl group R,, R,: hydrogen, -5o, H and its metal salt, -CO
O) I and its metal salts, lower alkyl groups, alkoxy groups.

Halogen, hydroxyl group R7, R,, R,, R1°: hydrogen, lower alkyl group, alkoxy group, halogen R41: hydrogen, -NO Next, each constituent material used in the present invention will be explained.

The conductive support is intended to supply charges of opposite polarity to the charged charges to the substrate side, and has an electrical resistance of 1.
0" Ωcm or less and can withstand the film formation conditions of the charge generation layer, charge transfer layer, and even undercoat layer. Examples of these include AQ, Ni, Cr,
Electrically conductive metals and alloys such as Zn and stainless steel, inorganic insulating materials such as glass and ceramics, and polyester and polyimide.

AQ, Ni, Cr, Zn, stainless steel, carbon, 5n02. Examples include those coated with an electrically conductive substance such as In, O, etc. and subjected to conductive treatment.

The charge transfer layer can be formed by dissolving or dispersing two charge transfer substances and a resin binder in a suitable solvent, coating the solution on a conductive substrate, and drying the solution. Moreover, a plasticizer, a leveling agent, etc. can also be added if necessary.

Charge transfer substances include poly-N-vinylcarbazole and its derivatives, poly-γ:carbazolylethylglutamate and its derivatives, pyrene-formaldehyde condensate and its derivatives, polyvinylpyrene, polyvinylphenanthrene, oxazole derivatives, oxadiazole derivatives. , imidazole derivatives, triphenylamine derivatives, 9-(p-diethylaminostyryl)anthracene, 1-bis-(4-dibenzylaminophenyl)propane.

Examples include electron-donating substances such as styryl anthracene, styryl pyrazoline, phenylhydrazones, and α-phenylstilbene derivatives.

Examples of the resin binder used in the charge generation layer include polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer. , polyvinyl acetate, polyvinylidene chloride, polyacrylate resin, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal,
polyvinyltoluene, poly-N-vinylcarbazole,
Examples include thermoplastic or thermosetting resins such as acrylic resin, silicone resin, epoxy resin, melamine resin, urethane resin, phenol resin, and alkyd resin.

The solvent at this time is tetrahydrofuran.

Dioxane, toluene, monochlorobenzene, dichloroethane, methylene chloride, etc. can be used.

The thickness of the charge transport layer is 5 to 40 μm, preferably 10 to 40 μm.
Approximately 25 μm is appropriate.

The charge generation layer is composed of a charge generation substance or a charge generation substance and a resin binder.

Examples of such resin binders include polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, and polyacetic acid. Vinyl, polyvinylidene chloride, polyacrylate resin, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly-N-vinyl carbazole, acrylic resin, silicone resin, epoxy resin, melamine resin, Examples include thermoplastic or thermosetting resins such as urethane resins, phenol resins, and alkyd resins.

The total amount of the binder resin is 100% of the charge generating substance.
It is appropriate to use 0.01 to 200 parts by weight, preferably 1 to 50 parts by weight. The polymer and/or copolymer must be contained in an amount of at least 0.01 part by weight, preferably 1 part by weight or more, based on 100 parts by weight of the charge generating substance.

As the charge generating substance, for example, CI Pigment Blue 25 [Color Index (CI) 21180]
, CI Pigment Red 41 (CI 21200)
, C.I. Acid Red 52 (C-45100), C.I. Basic Red 3 (CI 45210), and a phthalocyanine pigment having a porphyrin skeleton,
Azulenium salt pigments, squalic salt pigments, azo pigments with a carbazole skeleton (described in JP-A-53-95033), azo pigments with a stilstilbene skeleton (
(described in JP-A No. 53-138229), azo pigments having a triphenylamine skeleton (described in JP-A-53-1325)
47), azo pigments having a dibenzothiophene skeleton (described in JP-A No. 54-21728), azo pigments having an oxadiazole skeleton (described in JP-A-54-1
2742), azo pigments having a fluorenone skeleton (described in JP-A-54-22834), azo pigments having a bisstilbene skeleton (described in JP-A-54-177)
33), an azo pigment having a distyryloxadiazole skeleton (described in JP-A-54-2129),
), azo pigments having a distyrylcarbazole skeleton (described in JP-A-54-17734), triazo pigments having a carbazole skeleton (described in JP-A-57-195767 and JP-A-57-195768), etc. In addition, CI Pigment Blue 16 (CI 74100)
Phthalocyanine pigments such as Sea Eye Butt Brown 5
(CI 73410.), Sea Eye Bat Die (CI
73030), Argo Scarlet B (manufactured by Violet Co., Ltd.), Indus Thread Scarlet R
Organic pigments such as perylene pigments (manufactured by Bayer) can be used.

Among these charge-generating substances, azo pigments are particularly preferred, and among azo pigments, disazo pigments and trisazo pigments shown below are most preferred.

Examples of azo pigments are shown below.

The thickness of the charge generation layer is suitably about 0.1 to 10 ILm, preferably 2 to 8 μm.

The charge generation layer can be formed by dissolving or dispersing a resin binder and a charge generation substance in a suitable solvent, applying the solution, and drying the solution. As a solvent, benzene, toluene, xylene, methylene chloride, dichloroethane, monochlorobenzene, dichlorobenzene, ethyl acetate, butyl acetate, methyl ethyl ketone, dioxane, tetrahydrofuran, cyclohexanone, methyl cellosolve, ethyl cellosolve, etc. can be used alone or in combination. can.

In the present invention, at least one compound represented by the general formulas (1) to (VIII) is added on the charge generation layer as a layer for preventing charge injection due to corona charging and trapping of charge carriers during repeated use. An intermediate layer is provided.

Specific examples of the compounds represented by the general formulas (1) to (VIII) are shown below.

Note that [] represents C, INn (color index Nα).

[-Formula (1) and -Formula (specific examples of old compounds)] (4
7000) C,1,5olvent Yellow
33C, 1, Food Yellow 13 (4701
03C,L Ac1d Yellow 2υ (47015) Ac1d Dye (47020) Ac1d Dye υ [-Specific example of compound of formula (III)] (29000)
C, 1, Direct Yellowts 44 (2f
1005) C, 1, Direct Yellow+
41tl, U (29010) C, 1, Direct Yellow
42 [Like 29035) C, 1, Direct Yellow
w 49 (29045) Direct Dye [-
Specific examples of compounds of formula (IV)] (29025) C, 1, Direct Yellow
50 [29030] C, 1, Direct Yel
lot+ 51 (290503C, I, Direct
Orange 49 (29055) C, L Di
rect Orange 69 [29060) C,
1, Direct Y61101131+(29065
) C, 1, ro 1rect Red 79[-
Specific examples of compounds of formula (V)] (13060) Ac1d Dye (13065) C,1,Ac1d Yellow
36 [13110) Ac1d Dye (13080) C, 1, Ac1d Orange
5 (13090) C, 1, Ac1d Orange
1■ (13100) C,1,^cid Yellow
6 [Specific examples of compounds of general formula (VI)] (15510
) C,1,Ac1d Orange 71n (14600) C,1,Ac1d Orange 2
0 (16230) C, 1, Ac1d Orange
10l0 (14095) C, 1, Mordant Yellow
w 3 [Specific examples of compounds of general formula (■) and general formula (■)] (19540) C, 1, Direct Yellow
ow 9[19550] DirectDye(19
555) C, 1, Direct Yellow 2g
(13930) C, 1, Direct Yellow
18 (13950) C, 1, Direct Yel
low 27 (13970) Direct Dye
(13925) C, 1, Direct Yellow
w 22JI- (19556] C, I, Direct Yell
ow 29 The thickness of this intermediate layer is 0.05-3 μm, preferably 0.05-1 μm.

Further, in the present invention, it is necessary to provide a protective layer on the intermediate layer in order to improve wear resistance, damage resistance, etc.

Protective layer resins include ABS resin, AC5 resin, olefin vinyl copolymer resin, chlorinated polyether, allyl resin, phenol resin, polyacetal, polyamide,
Polyamideimide, polyarylate, polyallylsulfone, polyethylene, polybutylene terephthalate, polycarbonate, polyethersulfone, polyethylene,
Polyethylene terephthalate, polyimide, methacrylic toilet fat, polymethylpentene, polypropylene, polyphenylene oxide, polysulfone, polystyrene, AS
resin, butadiene-styrene resin, polyurethane, polyvinyl chloride, polyvinylidene chloride, epoxy resin and the like.

In addition, from the viewpoint of wear resistance, polytetrafluoroethylene resin, fluorine resin, and silicone resin can be added as additives to lower the friction coefficient and improve wear resistance and scratch resistance. Abrasion resistance can also be improved by dispersing inorganic compounds such as tin oxide and potassium titanate in the resin. The film thickness of this surface protective layer is 0.5 to lOμ■,
Preferably it is a 1-5μ fake.

Further, in the present invention, a subbing layer having a barrier function and an adhesive function can be provided between the conductive support and the charge transfer layer.

The undercoat layer can be formed of casein, polyvinyl alcohol, nitrocellulose, ethylene-acrylic acid copolymer, polyamide (nylon 6, nylon 66, nylon 61O9 copolymerized nylon, alkoxymethylated nylon, etc.), polyurethane, gelatin aluminum oxide, and the like.

The thickness of the subbing layer is 0.1 to 5μ, preferably 0.5 to 3μ.
μ is appropriate.

To apply each layer in the present invention, coating methods such as dip coating method, spray coating method, spinner coating method, bead coating method, wire bar coating method, blade coating method, roller coating method, curtain coating method, or screen printing method are used. This can be done using the law. Drying is preferably carried out by drying to the touch at room temperature and then heating. Drying by heating can be carried out at a temperature of 30 to 200° C. for a period of from 5 minutes to 2 hours, either stationary or under ventilation.

〔effect〕

Since the electrophotographic photoreceptor of the present invention has the above configuration,
It exhibits excellent sensitivity even in the short wavelength range, and has excellent durability without accumulation of residual potential or deterioration of charging performance.

〔Example〕

Hereinafter, the present invention will be explained in more detail with reference to Examples. Note that both parts and numbers are based on weight.

Example 1 The following charge transfer layer solution was coated on a conductive support by dip coating so that the film thickness after drying was 22-.

[Charge transfer layer coating liquid]

Polycarbonate (C-1400 manufactured by Konjinsha) 1
00 parts silicone oil (KF-50 manufactured by Shin-Etsu Chemical Co., Ltd.)
0.05 part dichloromethane 7
35 parts [Charge generation layer coating liquid] Azo pigment (Nal) 5 parts Cyclohexanone 95 parts were dispersed in a ball mill, 400 parts of cyclohexanone was added and dispersed to adjust the mill base, and 1 weight 2 of the charge generation substance was dispersed. containing.

Next, the charge generation layer coating liquid was applied onto the charge transfer layer by a spray method so as to provide O and Spa.

Next, polyamide resin (CM-8000 manufactured by Toshisha Co., Ltd.) 1 part methanol 49.5 parts n-
An intermediate layer forming solution containing 49.5 parts of butanol was prepared. Next, 0.05 to 0.07 parts of the compounds listed in Table 1 were added to 30 parts of this liquid,
Stir and dissolve. First, pass through one sip to remove undissolved matter and obtain an intermediate layer forming liquid. This intermediate layer forming liquid was applied by a spray method so that the film thickness after drying was 0.3 to 14 mm.

Furthermore, 60 parts of styrene/methyl methacrylate/2-hydroxytin oxide (manufactured by Sumima Cement Co., Ltd.), 100 parts of methyl ethyl ketone, and 100 parts of butyl acetate were dispersed in a ball mill, and 100 parts of methyl ethyl ketone and 200 parts of butyl acetate were added and further dispersed to obtain a mill base. It was adjusted. 10 parts of this mill base, 5 parts of methyl ethyl ketone,
The solution was let down with 5 parts of butyl acetate, and 1 part of Incyanate (Sumiman Bayer Urethane GmbH, N-75, solid content 75%) was added to this solution to prepare a coating solution. This liquid was spray coated onto the intermediate layer so that the film thickness after drying was 3 mm.

These photoreceptors were rotated at a rotation speed of 1000 rpo using the apparatus disclosed in Japanese Patent Application Laid-Open No. 60-100167.
It rotates with +, and a voltage of +6 KV is applied in the dark to cause corona discharge and charge the photoreceptor.

The charging potential was controlled to be 800Vo12t, and then light from a tungsten lamp with a color temperature of 2854° and a slit width of 6I was irradiated with the illumination intensity on the photoreceptor surface being 26 Qux/d. The amount of exposure required to attenuate the surface potential of the body to 80 Vout is E/. (Qux, se) was determined. Furthermore, the surface potential of the photoreceptor after irradiation with the same light for 30 sep was defined as the residual potential VR. In addition, these photoconductors are manufactured by Ricoh FT-
5510 and an image test was conducted. The charging and light intensity were set to a dark area potential of 800V and a light area potential of 80V. 2000
After copying, the sensitivity Ex/1o and residual potential Vn were measured using the above measuring method. Regarding light fatigue, place the drum under a white fluorescent lamp at a position where the illuminance on the drum surface is 1000 (lux).
Immediately after irradiation for 1 hour, vn was measured using the above device, and then,
After copying 2000 sheets using the actual machine, vR was measured in the same manner. The results are shown in Table-1.

Table-1 1): [11380) C,1,5olvent
Yellow 51tN 2): (11020) C, 1,5olvent
Yellow 2<0-N=1N (CI et al.) 2 3): (46025) Ba5ic Dye 4): (46005) C,1,Ba5ic Ora
nge 14■

Claims (1)

[Claims] (1) In an electrophotographic photoreceptor in which a charge transfer layer, a charge generation layer, an intermediate layer, and a protective layer are sequentially provided on a conductive support,
An electrophotographic photoreceptor characterized in that the intermediate layer contains at least one compound represented by the following general formulas (I) to (VIII). ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(II) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(III) ▲There are mathematical formulas, chemical formulas, tables, etc.▼( IV) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (V) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (VI) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (VII) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼(VIII) (R_1, R_2, R_4: hydrogen, lower alkyl group, alkoxy group, halogen R_3: hydrogen, hydroxyl group R_5, R_6: hydrogen, -SO_3H and its metal salt,
-COOH and its metal salts, lower alkyl groups, alkoxy groups, halogens, hydroxyl groups R_7, R_8, R_9, R_1_0: Hydrogen, lower alkyl groups, alkoxy groups, halogen A: ▲Mathematical formulas, chemical formulas, tables, etc.▼, ▲Mathematical formulas , chemical formulas, tables, etc. ▼ R_1_1: Hydrogen, -NO B: ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, ▲ mathematical formulas, chemical formulas,
There are tables, etc. ▼, D: ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼,