JPH05232718A - Electrophotographic sensitive member - Google Patents

Abstract

PURPOSE:To allow mechanical damage of a photoreceptor to remain locally by including specific compounds in a sensitive layer, enhancing the slipperiness without affecting other traits, and decreasing the contacting resistance with a cleaning blade or a developer. CONSTITUTION:A sensitive layer contains a compound as given by a formula as illustrated, where (a) and (b) represent integer conditioned as 0<=a<=b<=20 while R<1>, R<2>, R<3>, R<4> take independently either of hydrogen atom, alkyl radical, alkoxyl radical, aryloxy radical, aryl radical, and aralkyl radical. The compound is effectively used when included in the facial course of the sensitive layer, the best effect being exerted by the structure where the compound is included in the electric charge conveying layer of a laminate type photosensitive member. Normally the compound content of the layer is 0.0005-0.5 parts by weight to 100 parts by weight binder resin, but preferably between 0.005 and 0.3 parts by weight from the viewpoint of the durability and influence upon the electric characteristics, and further preferably between 0.01 and 0.1 parts by weight.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an electrophotographic photoreceptor. More specifically, the present invention relates to an electrophotographic photoreceptor having excellent mechanical properties.

[0002]

2. Description of the Related Art Electrophotographic technology has been widely used and applied not only in the field of copying machines but also in the field of various printers in recent years because of its ability to obtain instant images and high quality images. For photoconductors, 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. A photoreceptor using an organic photoconductive material, which has advantages such as easy and easy manufacture, has been developed.

Among organic photoconductors, a so-called laminated type photoconductor in which a charge generation layer and a charge transfer layer are laminated has been devised and is the mainstream of research. The multi-layer type photoconductor is a highly sensitive photoconductor obtained by combining a highly efficient charge generating substance and a charge transfer substance, and a photoconductor having a wide selection range of materials and high safety, Further, since the coating productivity is high and the cost is comparatively advantageous, the possibility of becoming the mainstream of the photoconductor is high and the coating has been earnestly developed.

[0004]

Usually, such a photoreceptor is repeatedly used in an electrophotographic process, that is, a cycle of charging, exposing, developing, transferring, cleaning, removing charge, and the like, so that it is subjected to various stresses and deteriorates. Strongly oxidizing ozone or NO _X is or apply any chemical damage to the photosensitive layer Examples of such degradation generated from a corona charger which is normally used as, for example, chargers, carriers generated in the image exposure (current) photosensitive There are chemical and electrical deteriorations such as the photosensitive layer composition being decomposed by flowing in the layer, static elimination light, and light from the outside. Also, as another deterioration, cleaning blades, rubbing of magnetic brushes, and developer,
There is mechanical deterioration such as abrasion and scratches on the surface of the photosensitive layer due to contact with paper and peeling of the film. In particular, such damage on the surface of the photosensitive layer is likely to appear on the copy image and directly deteriorates the image quality, which is a major factor limiting the life of the photosensitive member. That is, in order to develop a photoreceptor having a long life, it is an essential condition to improve electrical and chemical durability as well as mechanical strength. In order to increase the mechanical strength of the photoreceptor, for example, an example in which an overcoat layer is provided (JP-A-61-72256), and a binder polymer having high abrasion resistance is used (JP-A-57).
-30841), an example of using a polymer having a small friction coefficient (JP-A-60-260045), and an example of decreasing the friction coefficient of the photosensitive layer surface (JP-A-1-307).
761 and JP-A-56-126838).

However, it is the actual situation that these cases often have problems such as insufficient effect and adverse effects on other characteristics.

[0006]

Therefore, the inventors of the present invention pay particular attention to the slipperiness of the surface among the mechanical strengths, reduce the contact resistance with a cleaning blade or a developer as much as possible, and apply it to a photosensitive member. In order to minimize the potential damage, we conducted a thorough study on a method for improving the slipperiness of the surface of the photoconductor. As a result, they have found that the inclusion of a specific compound in the photosensitive layer can enhance the slipperiness without adversely affecting other characteristics.

That is, the gist of the present invention is an electrophotographic photosensitive member having at least a photosensitive layer on a conductive substrate, wherein the photosensitive layer contains a compound represented by the following general formula (1). Exists in photographic photoreceptor. General formula (1)

[0008]

[Chemical 2]

(Where a and b are 0 ≦ a ≦ b ≦ 20
And R ¹ , R ² , R ³ , and R ⁴ each independently represent a hydrogen atom, an alkyl group, an alkoxy group, an allyloxy group, an allyl group, or an aralkyl group. ) Hereinafter, the present invention will be described in detail.

As a specific constitution of the photosensitive layer of the present invention: A charge generating layer containing a charge generating substance as a main component, a charge transporting layer containing a charge transporting substance and a binder resin as a main component are provided in this order on a conductive support. Laminated type photoreceptor. A reverse two-layer laminated photoreceptor in which a charge generating layer containing a charge generating substance as a main component and a charge transporting layer containing a charge transporting substance and a binder resin as a main component are laminated in the reverse order on a conductive support. A dispersion type photoreceptor comprising a photosensitive layer in which a charge generating substance is dispersed in a layer containing a charge transporting substance and a binder resin on a conductive support. An example of the basic form is such a configuration.

The photosensitive layer of the present invention is provided on a conductive support. As the conductive support, a metal material such as aluminum, stainless steel, copper or nickel, a polyester film having a conductive layer such as aluminum, copper, palladium, tin oxide or indium oxide on the surface, an insulating support such as paper The body is used. A well-known barrier layer which is commonly used may be provided between the conductive support and the photosensitive layer.

Examples of the barrier layer include an aluminum anodic oxide coating, an inorganic layer such as aluminum oxide and aluminum hydroxide, polyvinyl alcohol, casein, polyvinylpyrrolidone, polyacrylic acid, celluloses, gelatin, starch, polyurethane, polyimide, polyamide, Etc. organic layers are used. Examples of the charge generating substance used in the charge generating layer in the laminated type photoreceptor or the charge generating substance in the dispersion type photoreceptor include selenium and its alloys, arsenic-selenium, cadmium sulfide, zinc oxide, other inorganic photoconductive substances, phthalocyanine, Various organic pigments and dyes such as azo dyes, quinacridones, polycyclic quinones, pyrylium salts, thiapyrylium salts, indigo, thioindigo, anthanthrone, pyranthrone and cyanine can be used.

Among them, metal-free phthalocyanine, copper indium chloride, gallium chloride, tin, oxytitanium, zinc,
Azo pigments such as phthalocyanines coordinated with metals such as vanadium or oxides thereof, or chlorides thereof, monoazo, bisazo, trisazo, polyazos are preferable. The charge generation layer in the laminated type photoreceptor includes fine particles of these substances such as polyester resin, polyvinyl acetate, polyacrylic acid ester, polymethacrylic acid ester, polyester, polycarbonate, polyvinyl acetoacetal,
It may be used in a dispersion layer in the form of being bound with various binder resins such as polyvinyl propional, polyvinyl butyral, phenoxy resin, epoxy resin, urethane resin, cellulose ester and cellulose ether. In this case, the charge generating substance is used in an amount of 30 to 500 parts by weight based on 100 parts by weight of the binder resin, and the film thickness of the charge generating layer is usually 0.1 μm to 2 μm, preferably 0.15 μm to 0. It is in the range of 8 μm. Further, the charge generation layer may contain various additives such as a leveling agent, an antioxidant and a sensitizer for improving the coating property, if necessary. The charge generation layer may be a vapor deposition film of the above charge generation material.

In the dispersion type photoreceptor, it is necessary that the particle size of the charge generating substance is sufficiently small, preferably 1 μm.
It is more preferably 0.5 μm or less. The amount of the charge generating substance dispersed in the photosensitive layer is, for example, 0.5 to 5
If it is in the range of 0% by weight but too small, sufficient sensitivity cannot be obtained, and if it is too large, there are adverse effects such as deterioration of charging property and sensitivity, and more preferably in the range of 1-20% by weight.
The charge transport layer in the laminated type photoreceptor is basically composed of the compound represented by the above general formula (1) together with the charge transport material binder resin. In the case of the dispersion type photoreceptor, the charge transport material, binder resin and The charge generating substance is dispersed in the charge transport medium containing the compound represented by the general formula (1) as a main component.

Examples of the charge transport material used in the charge transport layer of the laminated photoreceptor or the charge transport material used in the dispersion photoreceptor include carbazole, indole, imidazole, oxazole, and pyrazole.
Heterocyclic compounds such as oxadiazole, pyrazoline, and thiadiazole, aniline derivatives, hydrazone compounds, aromatic amine derivatives, stilbene derivatives, and electron-donating substances such as polymers having groups of these compounds in the main chain or side chains. Is mentioned.

Examples of the binder resin used in the charge transport layer of the laminated type photoreceptor or the binder resin used in the dispersed type photoreceptor include vinyl polymers such as polymethylmethacrylate, polystyrene and polyvinyl chloride, and the like. Examples thereof include copolymers, polycarbonates, polyesters, polyester carbonates, polysulfones, polyimides, phenoxys, epoxies, silicone resins, and the like, and partially cross-linked cured products thereof can also be used.

In the present invention, the substituents R ^{1 to} R in the compound represented by the general formula (1) contained in the photosensitive layer.
Each of ⁴ independently represents a hydrogen atom, an alkyl group such as a methyl group and an ethyl group, an alkoxy group such as a methoxy group and an ethoxy group, an allyloxy group, an allyl group or a benzyl group, and an aralkyl group such as a phenylethylene group. In addition, a and b are integers of 0 ≦ a ≦ b ≦ 20, but if the value of a and / or b becomes too large, the solubility in a solvent decreases, so more preferably 0 ≦ a ≦ b ≦ 15. Is.

The compound represented by the general formula (1) contained in the photosensitive layer of the present invention may be a compound having a single structure in which a and b are constant values,
Further, a compound containing two or more kinds of compounds having different values of a and / or b may be included, but the latter case is preferable from the viewpoint of ease of production of the compound. The structures of typical compounds are shown below, but the structures are not limited thereto.

[0019]

[Chemical 3]

[0020]

[Chemical 4]

[0021]

[Chemical 5]

In the present invention, it is effective that the compound represented by the general formula (1) contained in the photosensitive layer is contained in the outermost layer constituting the photosensitive layer for use, and in particular, it is laminated. It is most effective when contained in the charge transport layer of the photoconductor. The content ratio of the compound represented by the general formula (1) is usually 0.0005 to 0.5 part by weight with respect to 100 parts by weight of the binder resin in the layer containing the compound. From the viewpoint of durability, it is preferably 0.005 to 0.3 part by weight, more preferably 0.01 to 0.1 part by weight.

The charge-transporting layer of the multi-layer type photoreceptor may contain various additives such as antioxidants and sensitizers, if necessary. The thickness of the charge transport layer is usually 10 to 60 μm, preferably 10 to 45 μm. The thickness of the photosensitive layer of the dispersion type photoreceptor is usually 5 to 50 μm, more preferably 10 to 4 μm.
It is in the range of 5 μm. Also in this case, known plasticizers for improving film-forming properties, flexibility, mechanical strength, etc., additives for suppressing residual potential, dispersion aids for improving dispersion stability, and coating properties Leveling agents and surface active agents such as silicone oil, fluorine-based oil and other additives may be added for improvement.

Further, these photoreceptors may be provided with an overcoat layer mainly composed of a conventionally known thermoplastic or thermosetting polymer as the outermost surface layer. These photosensitive layers are formed on the conductive support by known methods such as roll coating, bar coating, dip coating, spray coating and multi-nozzle coating. As a method for forming each layer, a known method such as sequentially coating a coating solution obtained by dissolving or dispersing a substance contained in the layer in a solvent can be applied.

[0025]

The electrophotographic photoreceptor containing the specific compound in the photosensitive layer according to the present invention has very good surface slipperiness without affecting electrical characteristics and the like. The scratches due to the developer are less likely to occur, and the durability of the photoconductor is dramatically improved. Therefore, it can be used in a high-speed copying machine or printer without any problem.

[0026]

EXAMPLES The present invention will be described in more detail with reference to Examples and Comparative Examples, but the invention is not limited thereto.

Example 1 10 parts by weight of a bisazo compound represented by the following structural formula (1) was added to 150 parts by weight of 4-methoxy-4-methylpentanone-2, and the mixture was pulverized and dispersed by a sand grind mill. It was The pigment dispersion obtained here was used as polyvinyl butyral (manufactured by Denki Kagaku Kogyo KK, trade name # 6000-).
C) was added to the 5% 1,2-dimethoxyethane solution to finally prepare a dispersion having a solid content concentration of 4.0%. The dispersion thus obtained is applied to the surface of a polyethylene terephthalate film on which aluminum is vapor-deposited using a wire bar, and a charge generation layer is provided so that the dry film thickness is 0.4 g / m ^2. It was

[0028]

[Chemical 6]

Next, the following structural formula (2) is formed on the charge generation layer.
95 parts by weight of a hydrazone compound represented by the following formula, 0.05 part by weight of a compound represented by the following structural formula (3) and 100 parts by weight of a polycarbonate resin represented by the following structural formula (4).

[0030]

[Chemical 7]

(A mixture of 0 ≦ a ≦ b ≦ 15 and the average value of the sum of a and b is 9)

[0032]

[Chemical 8]

Further, 8 parts of 2,6-di-t-butylhydroxytoluene and dimethyl silicone oil (viscosity 10
Centistokes) 0.03 parts of 1,4-dioxane,
After applying a solution dissolved in a mixed solvent of tetrahydrofuran with an applicator, 30 minutes at room temperature and 30 minutes at 125 ° C.
After minute drying, the charge transport layer was provided so that the film thickness after drying was 21 μm.

Example 2 The compound represented by the structural formula (3) in Example 1 was treated with 0.
A photoreceptor B was prepared in the same manner as in Example 1 except that the amount of 01 parts by weight was used. Comparative Example 1 A comparative photoconductor C was prepared in the same manner as in Example 1 except that the compound represented by the structural formula (3) was omitted.

Photoreceptors A, B and C thus prepared
A photoconductor characteristic measuring machine [Model EPA manufactured by Kawaguchi Electric Co., Ltd.
It was mounted on a -8100 and charged so that the current flowing into the aluminum surface was 72 μA, and then exposure and charge elimination were performed, and the chargeability (Vo) at that time and the decrease in potential after leaving for 1 second from the start of charging (dark Attenuation, DD), Half exposure sensitivity (E
_1/2 , reference potential 500 V), and residual potential (Vr) were measured. The results are shown in Table-1. From these results, it is found that all the photoconductors have a small dark decay and a low residual potential level, which is a good result, and that the compound represented by the structural formula (3) does not affect the electrical characteristics. ..

[0036]

[Table 1] Table-1 Photoreceptor Vo (V) DD (V) Vr (V) E _1/2 [lux · sec] A 960 48 4 0.87 B 951 51 5 0.88 C (Comparative example) 1011 54 3 0.87

Example 3 The dispersion liquid for forming the charge generation layer and the charge transport layer prepared in Example 1 was 30 mm in diameter and 250 in length.
mm, 1 mm thick aluminum cylinder is sequentially applied by the dip method, and the charge generation layer has a film thickness of 0.4 g /
m ² , drum-like photoreceptor A ′ having a charge transport layer thickness of 21 μm
It was created. Example 4 A drum-shaped photosensitive member B'corresponding to Example 2 was prepared in the same manner as in Example 3. Comparative Example 2 A drum-shaped photosensitive member C ′ corresponding to Comparative Example 1 was prepared in the same manner as in Example 3.

Each of these photoconductors A ', B'and C'is fixed on a surface tester [Haydon manufactured by Shinto Kagaku Co., Ltd.], and the cleaning blade in the longitudinal direction of a cleaning blade used in a commercially available copying machine is fixed. The edge was applied to the photoconductor at an angle of 45 ° parallel to the circumferential direction, a load of 50 g was placed, the cleaning blade was moved at 50 mm / min in the longitudinal direction of the photoconductor, and the frictional force at that time was measured. The results are shown in Table-2. As can be seen from these results, the photoreceptor of the present invention is
It can be seen that the slipperiness of the surface is significantly improved.

[0039]

[Table 2]

Claims (1)

[Claims] 1. An electrophotographic photoreceptor having at least a photosensitive layer on a conductive substrate, wherein the photosensitive layer contains a compound represented by the following general formula (1). General formula (1) (In the formula, a and b are integers of 0 ≦ a ≦ b ≦ 20, and R ¹ , R ² , R ³ , and R ⁴ are each independently a hydrogen atom, an alkyl group, an alkoxy group, an allyloxy group. , Represents an allyl group or an aralkyl group.)