JPS5931957A - Electrophotographic receptor - Google Patents

Abstract

PURPOSE:To provide a photoreceptor not causing production of ozone and problems due to its production, by forming a photosensitive layer contg. three components of a specified perylene pigment, poly-N-vinylcarbazole, and a specified electron acceptor. CONSTITUTION:An electrophotographic receptor has a photosensitive layer contg. a perylene pigment represented by the shown formula, poly-N-vinyl-carbazole, and an electron acceptor of a benzene deriv. substd. on the nucleus by at least one radical selected from a group consisting of OH, COOH, carboalkoxyl, and carbohalide, and at least one radical or atom selected from a group consisting of nitro and halogen. Remarkably superior photosensitivity is obtained by either dispersing or dissolving said three components into the same photosensitive layer.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrophotographic photoreceptor, and more specifically,
The present invention relates to an electrophotographic photoreceptor having high photosensitivity and having a photosensitive layer containing a specific perylene pigment and an electron-accepting nvin'a of poly-N-vinylcarbashield '14r.

It has been known since 71Y- that a perylene pigment is a light-guiding substance η having an absorption wavelength in the 5-spectral light region.
Child Photo Month 1 Kan) Y two bodies are also known from Japanese Patent Application Laid-Open No. 17-503-0. The photoreceptor described in this publication has a photosensitive layer mainly consisting of a perylene pigment and a charge transport material. If the transport substance or trinitrofluorenone is 'n4', the child transport substance is used.
The structure of the photosensitive layer may be a layered structure in which a layer of perylene pigment and a layer of charge transport material A are laminated as independent layers, or a layered structure in which perylene pigment and a layer of charge transport material A are laminated as independent layers, or a layered structure in which perylene pigments and a layer of charge transport material A are laminated as independent layers. Dispersed structures, distributed together in one layer, can be used. [-However, this laminated type photoreceptor has problems in durability, sensitivity, etc., and the dispersion type photoreceptor has problems in sensitivity, and both do not drop at T11). For example, a multilayer photoreceptor with a poly-N-vinylcarbazole layer is generally coated with a layer of L/N pigment before charge retention during corona charging (electron acceptability) and during exposure. It has excellent sensitivity. However, this pli
(7') The photoreceptor is a so-called negatively charged type photoreceptor (generally, it is charged by cathode corona discharge).

Cathode corona discharge easily generates ozone (the oxidizing effect of this ozone causes deterioration of the photoreceptor and shortens the life of the photoreceptor, and in the case of VC, ozone contaminates the copying environment, etc.). Negatively charged photoreceptors such as
It has not yet been put into practical use due to problems such as contamination. For example, a laminated photoreceptor has a layer containing trinitrofluorenone using a phenoxy resin as a binder resin on a layer of perylene N1 material vacuum-deposited on a conductive support. The culm has low sensitivity and no attenuation is observed.

2. A photosensitive layer prepared by fractionating perylene MfI and BoIJ N-vinylcarbazole or trinitrofluoreno/in a phenoxy resin at t. Th14: Dispersion type provided on support -1-) Y: Body) Y; Sensitivity (determined later, E%)
7) 9. 10 Current practical average level requiring higher photosensitivity than LIIX-8eC
, is not necessarily sufficient m"-"'))16',
・. Therefore, these photoreceptors have not yet been put into practical use.

Therefore, it is an object of the present invention to provide positive charging by anode corona discharge without causing problems such as generation of ozone, deterioration of the photoreceptor due to generated ozone, shortening of life, and contamination of the copying environment. The object of the present invention is to provide a positive band type electrophotographic photoreceptor that can realize electrophotography.

Another object of the present invention is to provide a practical electrophotographic photoreceptor that utilizes the phototetraelectricity of perylene pigments.

Another object of the present invention is to provide an electrophotographic photoreceptor having a photosensitivity that is at or exceeds the current average level for each actual photoreceptor.

These objects are achieved by the electrophotographic photoreceptor of the present invention, which has a photosensitive layer containing five components: a specific perylene pigment, poly-N-vinylcarbazole, and a specific electron-accepting substance.

That is, the present invention uses a perylene pigment (hereinafter, perylene mFl (a
), (2) poly-N-vinylcarbazole and (3) at least one group selected from the group consisting of a hydroxyl group, a carboxyl group, a carboalkoxyl group and a carbohalide group, a nitro group and a halogen. Contains an electron-accepting substance (hereinafter referred to as electron-accepting substance (b)) consisting of a benzene derivative whose nucleus is substituted with a first small group or atom selected from the group consisting of atoms.
1 relates to a photoreceptor having a photosensitive layer.

In general, it is known that strong chemical substances such as V-IJ-N-vinyllupezole cause electronic interactions with electron-accepting substances to form charge-transfer complexes.
There are 1. (2) If the child-accepting substance has a suitable electron affinity and electron transport ability, the formed complex exhibits strong optical absorption.

It is also known that it brings about the optical sensitizing effect of IJ-N-vinylcarbazole. However, the electron-accepting substance s<bl used in the present invention cannot form a complex exhibiting strong optical absorption with BoIJ N-vinylcarbazole, and therefore, in foggy white light, BoIJ It does not show any optical sensitization effect on N-vinylcarbazole. Furthermore, i) the V-accepting substance (b) used in the present invention brings about (i) an optical desensitizing effect on the perylene pigment (a). That is, the electron-accepting substance (bl) tends to be adsorbed onto the surface of the perylene pigment (3) and decrease the dark conductivity t14 degree and photoconductivity of the perylene pigment itself. This has been confirmed through experiments.

As described above, the electron-accepting substance (b) used in the present invention has an optical desensitizing effect on the perylene pigment (a), and an optical sensitizing effect on the polyJN-vinylcarbazole. Despite having nothing to bring,
It is surprising that extremely good photosensitivity can be obtained by dispersing or dissolving the berylene PI (a), poly-N-vinylcarbazole, and electron-accepting substance (b) components in the same photosensitive layer. It is.

The present inventor believes that the reason why extremely good photosensitivity can be obtained by the combination of these three components is as follows. ff1l Perylene pigment (al and poly-
With N-vinylcarbazole and γ ■ 8 particles, the perylene face F4 (lL) is produced by exposure to light /! The generated photoheavy holes are injected into poly N-vinylcarbazole and transported. On the other hand, the surface of perylene pigment (a) is relatively strong (・11
Electron-accepting 'm'j;l (b
) are adsorbed, these (a) and (b) phase 7L production J
The surface state of the perylene pigment (at) undergoes some chemical modification due to fl, and as a result, the W generated by the excessive excitation of the perylene pigment (a) and the carrier are simultaneously generated light iF.
It is immediately donated to the electron acceptor i(bl) without recombining with the hole.

At the same time, it is considered that extremely good photosensitivity can be obtained by efficiently injecting and transporting photogravimetric holes into the boIJ-N-vinylcarbazole.

The electron-accepting substance η, which can be added to a dispersed photoreceptor containing perylene pigment (a) and poly-N-vinylcarbazole to significantly improve its photosensitivity, is an electron-accepting substance η that can be added to a dispersed photoreceptor containing perylene pigment (a) and poly-N-vinylcarbazole to significantly improve its photosensitivity. It is a receptive substance (b). bo17
Ranil, fluoranil, fromanil, which are known as good photosensitizers for N-vinylcarbazole,
An electron-accepting substance such as 2#4,7-toIJ nitrofluorenone was added to a dispersed photoreceptor containing perylene pigment (11) and poly-N-vinylcarbazole, as will be clarified in the comparative example below. However, no substantial improvement in the photosensitivity of the photosensitive layer was observed. Based on this fact, the electron-accepting substance added for the purpose of photosensitizing a decomposable photoreceptor containing perylene (perylene) and poly N-vinylcarbazole is
It is necessary to maintain appropriate electronic interaction with both the perylene pigment (2) and the poly-N-vinylcarbazole.

In general, those that possess strong electronic interactions that can serve as sensitizers for poly-N-vinylcarbazole are not suitable for achieving the purpose of the present invention.

Specific examples of the electron-accepting substance η (bl) used in the present invention include p-nitrobenzoic acid, In-2l-benzoic acid, filtrate, 4
-Dinitrobenzoic acid, 2,4-dinitrobenzoic acid, 2,
5-dinitrobenzoic acid, 3,5-dinitrobenzoic acid, 2
, 4-dichlorobenzoic acid, p-nitrobenzoic acid chloride, m-nitrobenzoic acid chloride, U, dinitrobenzoic acid chloride, p-methyl nitrobenzoate, 0
-Ditrophenol, p-nitrophenol%2.4-
Dinitrophenol, 2,4,6-dinito-17phenol (picric acid), 6,5-dinito'1-o-rit
/Zor=L, etc. can be mentioned.

1 to 6) are diagrams showing the cross-sectional structure of a body for electrophotography according to the present invention, and each figure shows a different embodiment.

The photoreceptor in FIG.
The photoreceptor in FIG. a charge transport layer (6) consisting of N-vinylcarbazole (4a);
Photosensitive JVI (2 ') is provided on a conductive FP support (1). The photoreceptor shown in FIG. 3 has a charge transport layer (7) consisting of boIJ-N-vinylcarbazole (48) and an N1-accepting material (4b), and a charge carrier generation layer (5) having the same structure as above. A photosensitive layer (2') consisting of a photosensitive layer (2') is provided on a conductive support (1).

In the photoreceptor according to the present invention, perylene pigment (
The charge 4j released from a) is an electron-accepting substance (b
), and the holes generated by the release of the carrier are injected into the polymer and transported by N-vinylcarbazole. Therefore, the photoreceptors shown in FIGS. 1 and 3 can be used as positive V type and negative V type photoreceptors, respectively, and the photoreceptor shown in FIG. 2 can be used as a positive V type photoreceptor. It can be used as a photoreceptor. but.

As clarified in the Examples described below, when the photoreceptor according to the present invention is used in combination with iEY? High photosensitivity can be obtained.In both the photoreceptors shown in vJ2 and Fig. 3, the photosensitivity strongly depends on the thickness of the charge transport layers (6) and (7); When the height is within the range of 1 to 5 ttm.

The thicker the layer, the more sensitive the photoreceptor is. On the other hand, the dependence of the photosensitivity of the positive charge #1 on the thickness of the body-generating layer (5) is small.

From this, we can understand why the photosensitivity of the photoreceptor increases with the increase in the charge transport layer (6) and the layer (6).
) and (7) have the effect of preventing recombination of electrons injected from the pores generated in the charge carrier generation layer (5) and the electrons injected from the conductive support (11). is possible,
It is also believed that this is because the hole transport ability of poly-N-vinylcarbazole in layers (6) and (7) strongly controls the photosensitivity of the photoreceptor.

The photoreceptor in FIG. 1 is made of poly-N-vinylcarbazole and
1 is applied to the perylene pigment (1) in a solution prepared by dissolving the child-receptive substance (b) in a suitable organic solvent, and the dispersion is applied to the body (1) and dried. It can be made. The photoreceptor in Figures 2 and 3 is made of polyester.
N-vinylcarbazole or an electron acceptor f together with it
A solution of fj(b) dissolved in a suitable solvent was applied and dried on the conductive support (1), and then the previous NI'7
It can be produced by applying and drying a dispersion similar to the above. In this case, as the conductive support (11), for example, a metal plate or foil such as aluminum, a plastic film coated with a metal such as aluminum, etc. can be used.

Perylene pigment (a) contained in the photosensitive layer (2) in FIG. 1 and the charge carrier generation layer (5) in FIGS. 2 and 6, BoIJ
-N-vinylcarbazole and electron-accepting substance (bl
The preferred ratio of the six components is 1 to 50 [it%] (7 and perylene sparing [8) to poly-N-vinylcarbazole.
, military, and child-receptive substance (b) in an amount of 0.1 to 5% by weight.

The preferred thickness of the layer is 5 to 5 for photosensitive layer (2) in FIG.
0 pa Figures 2 and 3, 4) Body developmental layer (
5) 6-201tm.

In Figures 2 and 6, the transport layer (6) has a force of 5 to 60 μm.

In any of the photoconductors shown in FIGS. 1 to 3, the IJ
Other binder resins can be used with N-vinylcarbazole. The binder resin is applied to the layer described above (2).
), (5), (6), and (7). Examples of such binder resins include acrylic resins, polyester resins, diallyl phthalate resins, polycarbonate resins, silicone resins, vinylidene chloride resins, salt-vinycetate copolymers, partially saponified products thereof,
Examples include vinyl acetate polymer. By using such a binder resin in combination, the adhesion between layers and between layers and support can be improved. The preferred proportion of the binder resin to be used is 5 to 30% by weight based on the bo17 N-vinylcarbazole. Further, in addition to the above-mentioned components, suitable amounts of plasticizers, auxiliary agents, etc. may be added to the photosensitive layer according to necessity.

The present invention will be explained in more detail with reference to Examples below. The part in each example means a seriously dangerous part.

Examples 1 to 4 and Comparative Examples 1 to 4 Each blended composition listed in Table 1 was milled in a glass pease mill for 2 hours.
A dispersion prepared by uniformly dispersing the dispersion over time was applied onto an aluminum substrate using a wire bar so that the dry film thickness was 10 μm, and this was dried at 100° C. for 2 hours or more. Charging rp of the electrophotographic photoreceptor thus created
! it'I: and photosensitivity were measured and the results are listed in Table 2. As one measuring machine [Paper γ Narayri-8
P-428J (for Icho? (<, made by Kisha)
Shino.

(g)6Kv and ←)l! The surface type of the photoreceptor immediately after each voltage of SKV is applied to the surface of the photoreceptor. (v
l. Surface type 1 of the photoreceptor when the voltage is applied for 10 seconds after the voltage application is stopped.
■,. (v) is measured and felt) and the body's ability to hold a load is Vl.
Evaluation was made using the o/VO value.

The sensitivity of the photoreceptor was measured by exposing the surface of the charged photoreceptor to a white light image using a tungsten lamp.

When the exposure intensity is 5 Lux, the fog light required to reduce the surface potential after exposure to the initial surface potential of 14 (
Lux, 5ee) and the exposure required for the surface type (Sr to decrease to initial surface box f) χσ after exposure (:4dIi;
3'5 (Lux, 5ee) and 15 seconds after the start of Y1, measure the surface ■ A, Xun V+ 51 v l,
The sensitivity of the photoreceptor was evaluated based on these measurements.

41 Examples 5 to 13 and Comparative Examples 5 to 8 In place of p-nitrobenzoic acid chloride in Example 2, No. 6
Photoreceptors were prepared using the same formulation and method as in Example 1, except that the various electron-accepting materials listed in Tables 1 and 4 were used, and their properties were measured. The results are listed in the same table.

Examples 14 to 24 A solution having the following composition (11) was applied and dried on an aluminum substrate to form a charge transport layer with a thickness of 10 μm (-1
A dispersion having a composition of one ridge (branch) was applied thereon and dried to form a charge phase generation layer having a thickness of 41 tm.

Polyester glaze Jl (rVylon 2[10J
) 10 mixed solvent (1-luene/dioxane/
170 Tetrahydrofugin = 19.6719.6/1
．． 0) Electron-accepting substances in Table 5 1
2 Polyester resin ([Vylon 200J)
10m-terphenyl 41
The above-mentioned mixed solvent 280 The photoreceptor thus prepared is shown in FIG.

Example 25 A charge transport layer having a thickness of 10/1 m was formed by coating and drying a bath liquid having the composition of NEX I) below on an aluminum substrate, and on top of this a dispersion having the composition of (11) below. was applied and dried to form a charge carrier generation layer with a thickness of 4/1 m]
7.

Electron-accepting materials in Table 6 1.2 Polyester resin (IVylon 200J) 10
m-Terphenyl 41 Mixed solvent (toluene/dioxane/220 Tetrahydrofuran = 19.6/19.6/1.0) Poly-N-vinylcarbazole 164 Electronic receiver in Table 6? f substance 1,2 polyester resin (rv
ylon 2DOJ) 10m-terphenyl 41 above mixed solvent
280 The photoreceptor prepared in this way is
This is a photoreceptor having the structure shown in FIG. Its properties are listed in Table 6.

[Brief explanation of the drawing]

1 to 3 are sectional views of electrophotographic photoreceptors according to the present invention, respectively. (11... Conductive support (2), (2
f, (21'...Photosensitive layer (3)...Perylene pigment (4)...Charge transport medium (
4a) Poly-N-vinylcarbasol (4
h)・・・Electron-accepting substance

Claims (1)

[Scope of Claims] 1. At least one selected from the group consisting of a perylene pigment represented by (11), (2) poly-N-vinylcarbazole, and (3) a hydroxyl group, a carboxyl group, a carboalkoxyl group, and a carbohalide group. An electrophotographic photoreceptor having a photosensitive layer containing an electron-accepting substance consisting of one group and a benzene derivative whose nucleus is substituted with at least one group or atom selected from the group consisting of a nitro group and a halogen atom. A charge transport layer made of poly-N-vinylcarbazole was provided on a conductive support, and a charge-generating layer made of perylene pigment, poly-N-vinylcarbazole, and an electron-accepting substance was further provided on this layer. /l'5 Claims 1.1J1-sensitive γC; The photoreceptor according to claim 1, further comprising a charge generation layer comprising a perylene pigment, a +7-N-vinylcarbazole, and an electron-accepting substance. 1-5 for carbazole
2. The photoreceptor according to claim 1, which contains 0 M1% perylene pigment and 01 to 5% electron accepting material 44+.