JPH0498263A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain the photosensitive body which is greatly improved in ozone resistance and has excellent electric characteristics by adding a specific amine compd. to a photosensitive layer when a specific hydrazone compd. is used as a charge transfer material. CONSTITUTION:The photosensitive layer contg. at least a charge generating material, the charge transfer material and an alkyl amine compd. is provided on a conductive base. The charge transfer material is expressed by formula I. In the formula I, A1, A2, A3 denote a hydrogen atom, alkyl group, alkoxy group, alkenyl group, aryl group, heteroaryl group; A4, A5 denote an alkyl group, aryl group. The alkyl amine compd. is expressed by formulas II, III. In the formula II, B1, B2 denote a hydrogen atom, alkyl group aralkyl group. In the formula III, Z1 denotes the atom group necessary for constituting a nitrogenous alicycle. R2 denotes a hydrogen atom, alkyl group, cycloalkyl group, aralkyl group; R3, R4, R5, R6 denote a hydrogen atom or alkyl group, such as methyl group and ethyl group.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an electrophotographic photoreceptor.

Specifically, the present invention relates to an electrophotographic photoreceptor that is highly sensitive, has a low residual potential, has excellent ozone resistance, and has excellent stability and durability.

[Conventional technology]

In recent years, electrophotographic technology has been widely used and applied not only in the field of copying machines but also in the field of various printers because of its ability to provide instantaneous and high-quality images.

Regarding photoreceptors, which are the core of electrophotographic technology, inorganic photoconductors such as selenium, arsenic-selenium alloy, cadmium sulfide, and zinc oxide have been used as photoconductive materials in the past, but in recent years, films have been developed that can be formed without pollution. Photoreceptors using organic photoconductive materials have been developed, which have the advantages of being easy to manufacture. As organic photoreceptors, so-called dispersion type photoreceptors in which photoconductive fine powder is dispersed in a binder resin, and laminated type photoreceptors in which a charge generation layer and a charge transfer layer are laminated are known.

A laminated photoreceptor is a photoreceptor made by laminating a charge generation layer and a charge transfer layer containing a charge generation substance and a charge transfer substance on a conductive support, and usually the charge generation layer and the charge transfer layer are laminated in this order. However, photoreceptors in which the order of lamination is reversed are also known.

As described above, photoreceptors with several configurations have been proposed and studied, and photoreceptors with excellent charging properties and sensitivity have been developed. However, electrophotographic photoreceptors are used repeatedly in systems and are required to always have certain stable electrophotographic characteristics. , the current situation is that we have not yet obtained enough. In other words, with repeated use, potential decreases, residual potential increases, sensitivity changes, etc.
The copy quality deteriorates and the copy becomes unusable. Several factors are considered to be the cause of these deteriorations. Among them, it is known that oxidizing gases such as ozone and nitrogen oxides emitted from a corona discharge charger cause significant damage to the photosensitive layer. These oxidizing gases chemically change the materials in the photosensitive layer, resulting in various changes in properties.

For example, a decrease in charging potential, an upper limit of residual potential, and a decrease in resolution due to a decrease in surface resistance are observed, resulting in a significant decrease in image quality and shortening the life of the photoreceptor.

This change in characteristics depends on the type of charge transfer material used in the photoreceptor. Therefore, this corona resistance is a major factor when selecting a charge transfer material.

It has already been found that when the aforementioned hydrazone compound containing thiophene is used as a charge transfer substance, it has high sensitivity, extremely low residual potential, and excellent electrical stability and durability (for example, (Refer to Kaihei 1-319753).

However, it has been found that the problem with this charge transfer material is that it is susceptible to deterioration due to ozone, and its charging voltage significantly decreases under corona discharge.

[Problem to be solved by the invention] Conventionally, as a countermeasure against ozone deterioration, measures have been taken to efficiently exhaust and replace the gas around the corona charger to avoid the effect on the photoreceptor, and to prevent oxidation of the photoreceptor layer. Proposals have been made to prevent deterioration by adding inhibitors and stabilizers. For example, JP-A-62-105151 proposes the addition of an antioxidant having a triazine ring and a hindered phenol skeleton in the molecule (for example, JP-A-62-1051
(See Publication No. 51).

However, when the aforementioned hydrazone compound containing thiophene is used as a charge transfer substance, the current state is that sufficient ozone resistance effects cannot be obtained using known techniques and additives.

(Means for Solving the Problems) As a result of extensive research into improving the ozone resistance of organophotoreceptors containing a charge-generating substance and a charge-transfer substance, the present inventors discovered that a specific hydrazone compound was used as a charge-transfer substance. The present inventors have now completed the present invention by discovering that by adding a specific amine compound to the photosensitive layer, a photoreceptor with significantly improved ozone resistance and excellent electrical properties can be obtained.

That is, the gist of the present invention is to provide at least a charge-generating substance, a charge-transfer substance represented by the following general formula (I), ++ (wherein A+, A2 and A3 each independently represent hydrogen) on a conductive support. represents an atom, an alkyl group, an alkoxy group, an alkenyl group, an aryl group, or a heteroaryl group, and the alkyl group, alkoxy group, alkenyl group, aryl group, and heteroaryl group may have a substituent.Aa and As are alkyl or aryl group, which may have a substituent (, A4 and A.

may be directly connected. ) and an electrophotographic photoreceptor characterized by having a photosensitive layer containing an alkylamine compound represented by the following formula (Ila) or (nb).

(In the formula, B+ and Bz represent an alkyl group, a cycloalkyl group, or an aralkyl group, and these may have a substituent. R1 represents a hydrogen atom, an alkyl group, or an aralkyl group; may have a substituent.B+, Bz, and R+ may be the same or different from each other.) (In the formula, Z represents an atomic group necessary to constitute a nitrogen-containing alicyclic ring. .R2 is a hydrogen atom, an alkyl group,
It represents a cycloalkyl group or an aralkyl group, and the argyl group, cycloalkyl group, and aralkyl group may have a substituent. R3, R4, Rs and R6 each independently represent a hydrogen atom or an alkyl group. ) The present invention will be described in detail below.

The photosensitive layer of the present invention contains at least a charge generating substance and a charge transporting substance. More specifically, a laminated photoreceptor in which a charge generation layer containing a charge generation substance as a main component, a charge transfer layer containing a charge transfer substance and a binder resin as main components are laminated in this order on a conductive support.

- An inverted two-layer photoreceptor in which a charge transfer layer containing a charge transfer substance and a binder resin as main components and a charge generation layer containing a charge generation substance as main components are laminated in this order on a conductive support.

- A dispersion type photoreceptor in which a charge generating substance is dispersed in a layer containing a charge transfer substance and a binder resin on a conductive support.

An example of a basic configuration is a configuration like this.

These photosensitive layers are formed on a conductive support by a known method such as roll coating, par coating, dip coating, or spray coating. If necessary, a barrier layer of polyamide, polyurethane, aluminum oxide, etc. may be provided between the conductive substrate and the photosensitive layer. Further, a protective layer made of polyamide, thermosetting silicone resin, crosslinked acrylic resin, etc. may be provided on the surface of the photosensitive layer, if necessary.

Various known conductive supports can be used. For example, metal drums made of aluminum, copper, nickel, stainless steel, etc.;
Plastic films that have been subjected to conductive treatment such as vapor-depositing or sputtering conductive oxides, or applying conductive substances such as metal powder, carbon black, copper iodide, and tin oxide together with binder resin as necessary. Examples include plastic drums, glass drums, and paper.

As the charge generating substance used in the present invention, various inorganic and organic charge generating substances can be used. For example, inorganic charge-generating substances include various alloy materials mainly composed of selenium such as amorphous selenium, selenium-tellurium alloy, trigonal selenium, and arsenic triselenide; II-Vl such as cadmium sulfide and cadmium selenide. Group compound semiconductor material; known materials such as amorphous silicon and hydrogenated silicon are used in the form of fine particles.

In addition, phthalocyanine pigments are used as organic charge generating substances.
Perylene pigments, polycyclic quinones, quinacridone pigments, indigo pigments, squarylium salts, azo pigments, etc. can be used.

Among them, phthalocyanine pigments and azo pigments can be used as more preferable materials. Examples of phthalocyanine pigments include those described in the following formula.

×1 Examples of X include a hydrogen atom, a lower alkyl group, a lower alkoxy group, a di1.4 group, a cyano group, a halogen atom, and m is an integer from 0 to 4.

Various types of azo pigments can be used, but more preferred materials include monoazo pigments, bisazo pigments, trisazo pigments, and other polyazo pigments having at least one coupler component shown in the following formula.

The above M includes Cu, Fe, Mg, Si, and Ge.

Sn, Pb; InCl1. CaCl! ,,/i
! , phthalocyanine containing metal atoms such as Cn and TiO,
Examples include metal-free phthalocyanine with two hydrogen atoms added.

However, in the formula, A represents a divalent group of an aromatic hydrocarbon or a divalent group of a heterocycle containing a nitrogen atom in the ring.

In the case of a laminated structure, the charge generating substance is used as the main component constituting the charge generating layer, and may be used as a uniform layer formed by a method such as vapor deposition or sputtering (or in the form of fine particles). It may be used in a form dispersed in a binder resin. In this case, the binder resin includes polyvinyl acetic resin such as polyvinyl acetate, polyacrylic ester, methacrylate resin, polyester resin, polycarbonate resin, polyvinyl butyral, polyvinyl formal, etc. , phenoxy resin, cellulose ester,
Various binder resins such as cellulose ether, urethane resin, and epoxy resin can be used. The composition ratio of the charge generating substance and the binder resin is usually preferably in the range of 100:10 to 5:100 by weight, and a charge transporting substance may be mixed in this layer. It is preferable that the thickness of the charge generation layer is usually 0.1 to 10 μm. Further, in the case of the above-mentioned dispersion type photosensitive layer structure, the charge generating substance is dispersed in the form of fine particles in the matrix containing the charge transporting substance and the binder resin.

As mentioned above, the charge transfer substance used in the present invention is a compound atom represented by the following general formula (I); an alkyl group such as a methyl group, an ethyl group, or a propyl group; an alkoxy group such as a methoxy group or an ethoxy group; represents an alkyl group, an alkenyl group such as a butadienyl group, an aryl group such as a phenyl group, a naphthyl group; a heteroaryl group such as a thiophenyl group;
It may have a substituent such as an aryl group, an aralkyl group, an alkoxy group, or a hydroxyl group. A4. As represents an alkyl group such as a methyl group, ethyl group, or propyl group; an aryl group such as a phenyl group, a naphthyl group, or anthryl group;
These may have a substituent such as an alkyl group or an aryl group, and A4 and A may be bonded.

Specific examples of compounds represented by such general formulas are shown in Table 1 below.

(x) (xii) Exemplary Compound (xij) Various known resins can be used as the binder resin used together with the charge transport material. Thermoplastic resins and curable resins such as polycarbonate resins, polyester resins, polyarylate resins, acrylic resins, methacrylate resins, styrene resins, and silicone resins can be used.

Polycarbonate resin, which is particularly resistant to wear and scratches.
Polyacrylate resins and polyester resins are preferred.

Bisphenol components of polycarbonate resin include bisphenol A1, bisphenol C, and bisphenol Z.
Various known components such as can be used.

The blending ratio of charge transfer substance and binder resin is resin 10
For example, 20 to 200 parts by weight, preferably 40 to 150 parts by weight, based on 0 parts by weight. In the case of a laminated photoreceptor, the charge transfer layer is formed mainly from the above components, and the thickness of the charge transfer layer is usually 5 to 50 m, preferably 10 to 408 m.

In the case of a dispersion type photoreceptor, the charge generating substance is dispersed in the form of fine particles in a matrix mainly composed of a charge transfer substance and a binder resin in the above-mentioned compounding ratio, but the particle size must be sufficiently small. , preferably 111 m or less,
More preferably, it is used at 0.5 μm or less. If the amount of the charge generating substance dispersed in the photosensitive layer is too small, sufficient sensitivity cannot be obtained, and if it is too large, there are problems such as a decrease in charging property and a decrease in sensitivity. It is used in a range of % by weight, more preferably in a range of 1 to 20% by weight. The thickness of the photosensitive layer is usually 5 to 50 μm, more preferably 10 to 40 μm.

As described above, the alkylamine compound used in the present invention is a compound represented by the following formula Ua and I[b.

In formula (Ira), B+ and Bz are an alkyl group such as a methyl group, an ethyl group, a t-butyl group, an n-hexyl group, or an n-decyl group; a cycloalkyl group such as a cyclohexyl group; or a pencil group, a naphthylmethyl group, etc. represents an aralkyl group, which may have a substituent such as an alkyl group, an aryl group, or an alkoxy group. RI is a hydrogen atom;
Methyl group, ethyl group, t-butyl group, n-hexyl group,
It represents an alkyl group such as an n-decyl group; an aralkyl group such as a benzyl group or a naphthylmethyl group, and the alkyl group or aralkyl group may have a substituent. BB2. R, may be the same or different.

In formula Hb, 2. represents an atomic group necessary to constitute a nitrogen-containing alicyclic ring such as a hyperidine ring, a piperidone ring, a pyrrolidine ring, or a pyrrolidone ring, which may have a substituent. R2
is a hydrogen atom; methyl group, L-butyl group, n-hexyl group,
It represents an alkyl group such as an n-decyl group; a cycloalkyl group such as a cycloalkyl group; an aralkyl group such as a benzyl group or a naphthylmethyl group; the alkyl group, cycloalkyl group, or aralkyl group may have a substituent.

R3, Ra, R5, and R6 represent a hydrogen atom; or an alkyl group such as a methyl group or an ethyl group.

More preferred as the alkylamine compound are compounds having in the molecule at least one of the structural units represented by Uc, I'd, and Ice below.

(However, R3 and R4 are as follows i) ii)
1ii) and may be the same or different.

)+) CHzX +i) CH2CH2Y However, X and Y are respectively a phenyl group, a naphthyl group,
Aromatic residues such as anthryl group; aromatic heterocyclic residues such as thiophenyl group; cycloalkyl groups such as cyclohexyl group and cyclopentyl group; heterocycloalkyl groups such as tetrahydropyranyl group; It may have a substituent such as an aryl group, an aralkyl group, an alkoxy group, an aryloxy group, a hydroxyl group, a cyano group, or a halogen atom.

iii) A cycloalkyl group such as a cyclohexyl group or a cyclopentyl group, or a heterocycloalkyl group such as a tetrahydropyranyl group. These may have a substituent such as an alkyl group or an alkoxy group.

R7 represents hydrogen, an alkyl group, a cycloalkyl group, or an aralkyl group, and the alkyl group, cycloalkyl group, and aralkyl group each represent an alkyl group, an aryl group, an alkoxy group, an aryloxy group, a hydroxyl group, a cyano group, a halogen atom, etc. It may have a substituent such as. This R7
preferably has 3 or more carbon atoms, and sterically bulky ones such as tert-butyl group, benzyl group, and decyl group are particularly preferable.

(However, Z2 represents an atomic group necessary to constitute a containing alicyclic ring such as a piperidine ring, piperidone ring, pyrrolidine ring, or pyrrolidone ring, which may have a substituent, together with two methylene groups, and among them, A piperidine ring and a piperidone ring are particularly preferred. R8 may have a substituent such as a hydroxyl group, an alkoxy group, an aryl group, an alkyl group, or a halogen atom.

It represents an alkyl group, a cycloalkyl group, or an aralkyl group, and those having 3 or more carbon atoms such as n-propyl group and Hensyl group are particularly preferable. ) represents a kyl group, and the alkyl group and aralkyl group may have a substituent. R1゜+ R+
++ RIZ and RI3 represent an alkyl group such as a methyl group or an ethyl group. RzRI 5 + RI b represents a hydrogen atom or an organic residue. ) These-formation 11a, Il
Specific examples of the alkylamine compounds represented by b, Ilc, Ild, and IIe are shown in Table 2.

Table 2 Exemplary compounds (where R7 is a hydrogen atom; methyl group, ethyl group, n-
Alkyl groups such as propyl group and n-hexyl group; Arallic groups such as benzyl group and naphthylmethyl group These amine compounds are added to all or part of the photosensitive layer. Since deterioration progresses from the surface, it is preferable to add it to at least the surface layer. Further, when a protective layer or a blocking layer is provided, it is added to these layers as necessary.

The amount of the amine compound added is usually 0.1 by weight within the layer.
-20% by weight, more preferably 1-16 parts by weight.

Furthermore, the photosensitive layer of the present invention contains a known plasticizer to improve film formability, flexibility, mechanical strength, etc., an additive to suppress accumulation of residual potential, and a dispersion to improve dispersion stability. Auxiliary agents, leveling agents to improve coating properties, e.g.
Silicone oil and other additives may be added.

〔Effect of the invention〕

The electrophotographic photoreceptor of the present invention has electrophotographic properties equivalent to high sensitivity and low residual potential, is not easily affected by ozone and nitrogen oxides generated from the system, and has stable properties and image quality even after repeated use. It has the advantage of being a photoreceptor with extremely high durability.

The photoreceptor of the present invention can be used in a wide range of electrophotographic applications, such as electrophotographic copying machines and various printers.

〔Example〕

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.

Example 1 10 parts by weight of oxytitanium phthalocyanine was added to 200 parts by weight of dimethoxyethane, and after dispersion treatment with a sand grind mill, polyvinyl butyral resin (manufactured by Denki Kagaku Kogyo ■, trade name Denka Butyral #6000C) 5
Parts by weight were added to a solution prepared by dissolving 100 parts by weight of dimethoxyethane to obtain a dispersion. After drying this solution on a 75 μm thick polyester film coated with aluminum,
A charge generation layer was formed by coating at a coating amount of 4 g/rrf.

On this charge generation layer, 100 parts by weight of the exemplified compound (xiii) shown in Table 1 as a charge transfer substance, 100 parts by weight of polycarbonate resin (manufactured by Mitsubishi Kasei ■, Valex 703DA)
Exemplary compound (7) in Table 2 as part by weight and amine compound
, 8 parts by weight and 1.5 parts by weight of the following electron-withdrawing compound dissolved in 670 parts by weight of dioxane were coated to form a charge transfer layer such that the film thickness after drying was 20 μm. It was created.

Next, Sample IB was prepared in the same manner as Sample IA, except that Exemplified Compound (34) in Table 2 was added as an amine compound.

Comparative Example 1 For comparison, a comparative sample IC was prepared in the same manner as sample IA except that no amine compound was added.

In addition, a comparative sample ID was prepared by adding 3,5 di-tert-butyl-4-hydroxy-toluene (BHT), which is known as an ozone deterioration inhibitor for electrophotographic photoreceptors, instead of the amine compound.

Example 2 Sample 2A was prepared in the same manner as sample IA, except that exemplified compound (ii) in Table 1 was used as the charge transfer substance, and exemplified compound (ii) in Table 2 was used as the amine compound.
Sample 2B was prepared in the same manner as Sample 2A except that 8) was added.

Comparative Example 2 For comparison, Comparative Sample 2C was prepared in the same manner as Sample 2A, except that no amine compound was added.

Example 3 The exemplified compound (ix) in Table 1 was used as a charge transfer substance, and the exemplified compound (4) in Table 2 was used as an amine compound.

Samples 3A and 3B were prepared in the same manner as Sample IA except that (6) was used.

Comparative Example 3 Comparative Sample 3C was prepared in the same manner as Sample 3A except that no amine compound was added for comparison.

The electrophotographic properties of the samples prepared by the above method and comparative samples were evaluated using an electrostatic copying paper tester (Kawaguchi Electric Seisakusho, model 5P-428).

Charge voltage when negatively charged due to corona discharge with applied voltage set so that corona current is 22 μA, 1.01
Exposure amount required to halve the surface potential from 1450 to 1225 when irradiated with ux white light (El/2)
, and the residual potential 10 seconds after exposure was measured.

Next, in order to examine ozone resistance, a corona charger was placed in the box, a voltage of -7 kV was applied, and air was circulated using a fan provided to create a uniform atmosphere. The ozone concentration at this time was 35 ppm.

The charged voltage after being exposed to this atmosphere for 10 hours was measured, and the ratio to the charged voltage before exposure was defined as the potential retention rate.

These results are shown in Table 3.

Samples LA, LB, 2A, 3A, and 3B were all excellent in electrical properties such as sensitivity and residual potential, and ozone resistance.

Comparative sample IC, 2B to which no amine compound was added
, 3C has poor ozone resistance, and the well-known hindered phenolic antioxidant BHT is used instead of the amine compound.
It was found that the ozone resistance of Comparative Sample ID to which was added was insufficient.

As described above, the photoreceptor to which the amine compound of the present invention has been added has significantly improved ozone resistance and improved electrical properties such as sensitivity and residual potential compared to those without additives or those to which known antioxidants have been added. It was also found that the characteristics did not deteriorate at all.

Claims (1)

[Claims] (1) At least a charge-generating substance and a charge-transfer substance represented by the following general formula (I) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (I) (where A_1, A_2 and A_3 are , each independently represents a hydrogen atom, an alkyl group, an alkoxy group, an alkenyl group, an aryl group, or a heteroaryl group, and the alkyl group, alkoxy group, alkenyl group, aryl group, and heteroaryl group may have a substituent. .A_4 and A_5 represent an alkyl group or an aryl group, and these may have a substituent, and A_4 and A_5 may be directly bonded.) And, in the following general formula (IIa) or (IIb) 1. An electrophotographic photoreceptor comprising a photosensitive layer containing the alkylamine compound shown below. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (IIa) (In the formula, B_1 and B_2 represent an alkyl group, a cycloalkyl group, or an aralkyl group, and these may have a substituent. R_1 is a hydrogen atom, Represents an alkyl group or an aralkyl group, and the alkyl group and aralkyl group may have a substituent. B_1, B_2, and R_1 may be the same or different from each other.) ▲ Contains mathematical formulas, chemical formulas, tables, etc. ▼(IIb) (In the formula, Z_1 represents an atomic group necessary to constitute a nitrogen-containing alicyclic ring. R_2 represents a hydrogen atom, an alkyl group, a cycloalkyl group, or an aralkyl group; The aralkyl group may have a substituent. R_3, R_4, R_5 and R_6 each independently represent a hydrogen atom or an alkyl group.)