JPH02189559A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To eliminate the influence of ions in the case in which an acid is incorporated into photosensitive layers by constituting an under coating layer of an inorg. high-polymer material contg. zirconium and silicon. CONSTITUTION:The under coating layer 2 of the electrophotographic sensitive body constituted by providing the under coating layer 2 and the photosensitive layers 3, 4 on a conductive base body 1 is constituted of the inorg. high-polymer material contg. the zirconium and silicon. The under coating layer 2 is the coated film consisting of the inorg. high-polymer material contg. the zirconium and silicon, has a crosslinked structure and is formed by applying a soln. mixture composed of a zirconium chelate compd. or zirconium alkoxide and silane coupling agent and curing the coating. The high-reliability electrophotographic sensitive body which is not affected by use environment and does not generate any abnormality at all in image quality even when copying operations of many sheet of copies are carried out is obtd. in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an electrophotographic photoreceptor comprising a substrate, an undercoat layer and a photosensitive layer, and more particularly to an electrophotographic photoreceptor having an improved undercoat layer.

Conventional technology Conventionally, electrophotographic photoreceptors were used as charge-generating materials! It has been broadly classified into those using organic pigments and those using organic pigments, but in recent years, charge generation I! Many materials are used that function as electrophotographic photoreceptors by separating the 1% charge transport ability and the charge transport ability, and laminating functional layers that perform the respective functions. These so-called function-separated type electrophotographic photoreceptors have many advantages in terms of material selection and electrophotographic properties, so many recent electrophotographic photoreceptors are of the function-separated type. . As functionally separated electrophotographic photoreceptors, there are a number of commonly seen type electrophotographic photoreceptors, that is, those that use organic pigments as a charge-generating material.
Also known are those in which an inorganic pigment such as E is contained in a charge generation layer and an organic polymer layer is laminated as a charge transport layer.

In these functionally separated electrophotographic photoreceptors, an organic charge generation layer or an organic charge transport layer is provided on a conductive substrate, or in this case, unnecessary charge is injected from the conductive substrate into these layers. In order to prevent this or to improve the adhesion between the conductive substrate and these layers, an undercoat layer is often provided between the two.

Materials used for the undercoat layer include polyvinyl alcohol, polyvinylpyrrolidone, polyvinylpyridine, cellulose ethers, cellulose esters, polyamide, polyurethane, casein, ceratin, polyglutamic acid, a powder, starch acetate, amine starch, and polyacrylic acid. , polyacrylamide, etc., are not attacked by the solvent of the coating solution for forming the charge generation layer or charge transport layer applied on the undercoat layer, and do not cause problems in electrical characteristics. The one that doesn't exist is selected. Among them, polyamide-based resins have excellent adhesive properties as described above, have low residual potential in terms of electrical properties, and have good environmental stability, so they are often used with a film thickness of 2n or less.

Furthermore, attempts have been made to form an undercoat layer using a zirconium chelate compound or a zirconium alkoxide, or a silane coupling agent.

Problems to be Solved by the Invention However, the conventionally used resin materials, typified by these polyamide resins, inherently have the characteristic of easily absorbing moisture and tend to cause ionic conduction in the layer. When a resin material is used, it is affected by ions caused by impurities mixed into the layer and ions caused by organic and inorganic acids contained in the charge generation layer coated on the undercoat layer.

Therefore, as an electrophotographic photoreceptor is used for a long period of time, electrochemical reactions occur between the undercoat layer itself, the charge generation layers above and below it, and the surface of the conductive substrate. The ability to prevent unnecessary charge injection from the conductive substrate, which is required for undercoat dust, is abnormally lost or increases, resulting in white spots and black spots appearing on the printed copy image. It was found that this occurs. This problem occurs after a certain period of time after the start of use of the electrophotographic photoreceptor, so it was a problem that should be improved in terms of quality assurance.

Furthermore, depending on the combination with the charge generation layer, the undercoat layer using polyamide resin may change over time after the start of use, that is, depending on the combination with the charge generation layer,
It has been found that as the number of cycles increases, the residual potential increases, causing a problem of so-called fogging on images. When a silancagg ring agent is used, there are problems in terms of electrophotographic characteristics such as an increase in the surface potential of the exposed area and a high residence potential.

The present invention has been made to solve the above-mentioned problems in the conventional technology.

SUMMARY OF THE INVENTION An object of the present invention is to provide an electrophotographic photoreceptor with extremely high unilateral properties that does not cause any abnormality in image quality even when copying a large number of sheets without being affected by the environment in which it is used. It is in.

Means and Effects for Solving the Problems As a result of study, the present inventors have discovered that the above object can be achieved when the undercoat layer is formed using a specific inorganic polymer material, and have devised the present invention. It was completed.

That is, the present invention provides an electrophotographic photoreceptor comprising an undercoat layer and a photosensitive layer on a conductive substrate, wherein the undercoat layer is made of an inorganic polymeric substance containing zirconium and silicon. do.

The present invention will be explained in detail below. FIG. 1 is a schematic cross-sectional view of an example of the electrophotographic photoreceptor of the present invention. In the figure, 1 is a conductive support, 2 is an undercoat layer, 3 is a charge generation layer, and 4 is a charge transport layer. .

In the present invention, as the conductive support, known materials can be used, such as aluminum, stainless steel, etc., which can be suitably used.

A subbing layer is formed on the conductive support.

The undercoat layer is a coating film made of inorganic polymer Th12 containing zirconium and silicon, and has the following crosslinked structure.

X (in the formula, or represents a vinyl group, or an alkyl group containing a functional group such as a vinyl group, an epoxy group, a methacrylic group, an amino group, a mercapto group, or a urethane group). It is formed by applying and curing a mixed solution of a zirconium chelate compound or a zirconium alkoxide and a silane coupling agent.

Zirconium chelate compounds having 3.4.6.8 molecular coordination are generally used and are represented by the following formula.

M (Z rXi, 4.6.a) (wherein, M: metal ion or hydrogen ion (valence omitted) X: halogen atom, acetylacetone, ketoester,
(amino alcohol, glycol, human 1:17 acid, amino acid, etc.) Representative examples include zirconium tetraacetylacetonate, zirconium triraftate salt, zirconium tetraoxalate salt, zirconium hexafluoro salt, zirconium octafluoro salt, etc. can be given.

Zirconium alkoxide is represented by the formula %) (in the formula, R: alkyl group), and typical examples include zirconium tetraethoxide, zirconium tetrapropoxide,
Examples include zirconium tetrabutoxide.

Examples of the silane coupling agent include vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris-2-methoxyethoxysilane, vinyltriacetoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-methacryloxysilane, Viltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-chloropropyltrimethoxysilane, γ-2-
Aminoethylaminopropyltrimethoxysilane, γ-
Examples include mercapto-10-pyltrimethoxysilane, γ-ureidopropyltriethoxysilane, and β-3,4-epoxycyclohexylethyltrimethoxysilane. .

In the present invention, zirconium alkoxide and silane power
The mixing ratio with the y bling agent can be appropriately set as necessary. However, from the point of view of electrophotographic properties, the volume resistivity after coating film formation is 1010 to 1013Ω.
・Is it preferable to set the mixing ratio of both so that it becomes ■?
If the volume resistivity is higher than the above range, the surface potential and residual potential of the exposed part will increase, and if it is lower than the above range, it will no longer function as a blocking 1-, causing problems such as a decrease in charging potential. Occur.

A photosensitive layer is provided on the undercoat layer, and in the present invention, (e) the photolayer may have a single layer structure or a laminated structure.In the case of a single layer structure, a dye-sensitized ZnO photosensitive layer Examples include a CdS photosensitive layer, a photosensitive layer in which a charge-generating substance is dispersed in a charge-transporting substance, and the like.

Further, in the case of an N-layer structure, a charge generation layer and a charge transport layer are separated in R function. The charge generation layer and the charge transport layer may be stacked on the substrate in any order.

The charge generation layer is formed by dispersing a charge generation substance in a binder resin as required. Examples of charge generating substances include selenium and selenium alloys; CdS, CdSe, Cd5Se.
, ZnO, ZnS, and other inorganic photoconductors: Metal or eagle metal phthalocyanine pigments: Azo pigments such as bisazo pigments and trisazo pigments; squareium compounds, niazurenium compounds; perylene pigments; indigo pigments: quinacridone pigments: polycyclic quinone pigments nidianin Pigment: Xanthene dye:
Charge transfer complexes consisting of poly-tovinylcarbazole and trinitrofluorenone, etc.; eutectic complexes consisting of pyrylium salt dye and polycarbonate resin, etc. are available.

As the binder resin, well-known ones such as polycarbonate, polystyrene, polyester, polyvinyl butyral, polyamide, polyvinyl chloride, methacrylic acid ester polymer or copolymer, vinyl acetate polymer or copolymer, cellulose ester or ether can be used. , polybutadiene, polyurethane, epoxy resin, etc. are used.

The charge transport layer is composed mainly of a charge transport substance.

The charge transfer substance is not particularly limited as long as it is transparent to visible light and has charge transport ability, and specific examples include imidazole, pyrazoline, thiazole, oxadiazole, and oxazole. , hydrazone, ketazine, azine, carbazole, polyvinylcarbazole, and derivatives thereof, triphenylamine derivatives, stilbene derivatives, benzidine derivatives, and the like. A binder resin is used in combination if necessary, and examples of the binder resin include polycarpolyte, epoxy resin, phenol resin, polyarylate, polyester, polystyrene, styrene-acrylonitrile copolymer, polysulfone, and polymethacrylate. Examples include acid esters, styrene-methacrylic acid ester copolymers, and the like.

In the present invention, the photosensitive layer, particularly the charge generation layer, may contain an acid for the purpose of improving sensitivity or other purposes. Examples of the acid to be contained include organic acids such as mono-, di-, and trifluoroacetic acid. Examples of the acid include halogenated organic acids such as chloroacetic acid and chloroacetic acid, and examples of the inorganic acid include hydrochloric acid, sulfuric acid, and nitric acid. Even when the photosensitive layer formed on the undercoat layer contains an acid, the undercoat layer made of the above-mentioned inorganic polymer material can effectively fulfill its function.

EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples. In addition, all "parts" mean "parts by weight."

Example 1 20 parts of zirconium tetraacetylacetonate (ZC150, manufactured by Matsumoto Kosho Co., Ltd.) represented by the following structural formula 10 parts of γ-methacryloxypropyltrimethoxysilane (88503, manufactured by Shin-Etsu Chemical ■) represented by the following structural formula Alcohol 400 parts n-butyl alcohol 100 parts n-amyl alcohol
200 parts of the above components were stirred with a stirrer to prepare a coating solution for forming an undercoat layer. This coating solution was applied to the surface of an aluminum cylinder with a diameter of approximately 85 mm by spray coating method, air-dried for approximately 5 minutes, and then heated at 135°C for 1 hour.
After drying for 0 minutes, a subbing layer having a thickness of 0.4 was formed.

Next, 10 parts of dibromoanthanthrone was dispersed in a solution consisting of 1 part of polyvinyl butyral, 110.02 parts of trifluoroacetic acid, 0.06 part of hydrochloric acid, and 90 parts of cyclohexanone. The resulting dispersion was applied onto the undercoat layer by dip coating and dried at 100° C. for 10 minutes to form a charge generating layer having a thickness of 0.8 μm.

Furthermore, a charge transport layer was formed thereon in the following manner.

That is, N, N'-diphenyl-N, N'-bis(
3-methylphenyl)-[1,1'-biphenyl]-4
, 5 parts of 4' diamine as a charge transport material were dissolved in 40 parts of monochlorobenzene together with 6 parts of polycarbonate 2 resin, and the resulting solution was applied by dip coating to give 110
It was dried at ℃ for 1 hour to form a charge transport layer having a thickness of 20 .beta.m.

After the electrophotographic photoreceptor thus prepared was charged to a surface potential of 800 cm, copying operations including image exposure, development, transfer, and fixing were repeatedly carried out in accordance with conventional electrophotographic techniques. When this repeated copying operation was performed at high temperature and high humidity (28°C, 85% RH), 50,
Even after making 000 copies, no similar abnormality occurred in the image quality. In addition, the above electrophotographic photoreceptor was heated at 40°C and 85% R.
After the apparatus was used in the H environment for one month, an image quality test was conducted in the same manner as above, and no abnormality in the copied image due to deterioration of the coating film occurred. Furthermore, it was confirmed that even if more than 1,000 copies were made at a low temperature and low humidity of 10° C. and 15% RH, no abnormality occurred in the same image quality. In addition, 30KC
Even during V running, there were no defects in electrical characteristics such as an increase in residual potential, and good characteristics were exhibited.

Example 2 Zirconium tetrabutoxide: Z r (OC4Hg) 4 (ZA60, manufactured by Matsumoto Bunmensha) 40 parts γ
-Methacryloxypropyltrimethoxysilane (88503, manufactured by Shin-Etsu Chemical) 10 parts Ethyl alcohol 650 parts N-Butyl alcohol 300 parts N-Amyl alcohol 180 parts A coating solution for forming an undercoat layer was prepared using the above composition. This coating solution was applied to the surface of an aluminum cylinder by a spray coating method, dried at room temperature for about 10 minutes, and then dried at 135° C. for 5 minutes to form an undercoat layer with a thickness of 0.4.

Thereafter, a charge generation layer and a charge transport layer were formed in the same manner as in Example 1. Regarding the obtained electrophotographic photoreceptor, Example 1
When an evaluation test was conducted in the same manner as in Example 1, almost the same results as in Example 1 were obtained.

Example 3 Zirconium tetraacetylacetonate (7C150
, manufactured by Matsumoto Bunmensha) 20 parts γ-aminopropyltriethoxysilane 112N (CH
2) 3Si (QC2II5) 3 (KBE903,
(manufactured by Shin-Etsu Chemical) 11 parts methyl alcohol
400 parts n-butyl alcohol
100 parts n-amyl alcohol
200 parts of the above components were stirred with a stirrer to prepare a coating solution for forming an undercoat layer. Other than using this coating liquid,
An electrophotographic photoreceptor was produced in the same manner as in Example 1.

When an evaluation test was conducted in the same manner as in Example 1, almost the same results as in Example 1 were obtained.

Example 4 An undercoat layer was formed in the same manner as in Example 1. A charge generation layer was formed on the obtained undercoat layer. That is, a solution prepared by dissolving 87 parts of granular trigonal selenium and 13 parts of vinyl chloride-vinyl acetate copolymer (Trusion Vinyl VHCH, manufactured by Union Carbide) in 200 parts of n-butyl acetate was heated using an attritor. The mixture was dispersed for 24 hours. Next, 57 parts of n-butyl acetate was added to 30 parts of the obtained dispersion.
A dipping coating solution was prepared by adding 100% of the total amount of the solution and diluting it. This dip application contained several hundred 1) l of selenite.

This dip coating solution was applied onto the undercoat layer by a dip coating method and dried at 135°C for 10 minutes to form a charge generation layer with a film thickness of 0.2. A charge transport layer was formed.

The obtained electrophotographic photoreceptor was subjected to an evaluation test in the same manner as in Example 1, and the results were almost the same as in Example 1.
Even in an environment of 15% RH and 15% RH, more than 50,000 consecutive copies of good image quality were obtained. In addition, electrical characteristics are hardly affected by the environment, that is, 50,000
Even when more than one copy was made, copies of good image quality were obtained without producing any substantial residual potential.

Example 5 An undercoat layer was formed in the same manner as in Example 2, and a charge generation layer and a charge transport layer were formed in the same manner as in Example 4. When the obtained electrophotographic photoreceptor was subjected to an evaluation test in the same manner as in Example 1, almost the same results as in Example 1 were obtained.

Example 6 An undercoat layer was formed in the same manner as in Example 3, and a charge generation layer and a charge transport layer were formed in the same manner as in Example 4. When the obtained electrophotographic photoreceptor was subjected to an evaluation test in the same manner as in Example 1, almost the same results as in Example 1 were obtained.

Comparative Example 1 One part of 30% methoxymethylated nylon 8 was dissolved in a mixed solvent consisting of 3.8 parts of methyl alcohol, 2.6 parts of n-butyl alcohol, and 0.6 parts of water. The obtained solution was applied to the surface of an aluminum cylinder with a diameter of 851 m1 by dip coating method, air-dried for about 5 minutes, and then heated at 135°C for 10 minutes.
It was dried for a minute to form a subbing layer with a thickness of 1 μm.

On the formed undercoat layer, a charge generation layer and a charge transport layer were laminated in the same manner as in Example 1 to produce an electrophotographic photoreceptor.6 The obtained electrophotographic photoreceptor was laminated in the same manner as in Example 1. An evaluation test was conducted on December 17th. High temperature and high humidity (28℃, 85% R1 [
) When 20,000 copies were obtained, a large number of white spots appeared on the copied images, indicating that the coating film had deteriorated in quality. In addition, this electrophotographic photoreceptor was
After the device was kept in an environment of 0° C. and 85% old 1 for one month, an image quality test was conducted in the same manner as above, and many black spots appeared in the halftone image of the copy. Furthermore, after making continuous copies of about 30,000 sheets under low temperature and low humidity, the residual potential is several orders of magnitude higher.
The voltage increased by 0V, causing a slight capri in the image.

Comparative Example 2 An electrophotographic photoreceptor was produced in the same manner as in Example 1, except that the undercoat layer was formed by omitting zirconium tetraacetylacetonate from the undercoat layer forming components in Example 1.

The obtained electrophotographic photoreceptor had a high surface potential and residual potential in the exposed area, and especially in a low temperature, low humidity (10° C., 15% RH) environment, the residual potential increased after 7 repeated uses. The electrophotographic characteristics were inferior compared to the case.

Comparative Example 3 From the undercoat layer forming components in Example 1, 2. An undercoat layer was prepared in the same manner as in Example 1 except for γ-methacryloxypropyltrimethoxysilane. In that case, cracking occurred during drying, resulting in poor coating properties.

Comparative Example 4 The same charge generation layer and charge transport layer as in Example 4 were used, but
For the undercoat layer, a solution prepared by dissolving 1 part of polyvinyl alcohol in a mixed solvent of 26 parts of n-propertool and 6 parts of water was applied by dip coating onto an aluminum cylinder with a diameter of 85 cm.
A film with a film thickness of 0.5 μm that can be dried for 10 minutes at 35°C has a film thickness of 10,000 μm in an environment of 10°C and 15% RH.
When I made 0 consecutive copies, countless white spots appeared on the copies. In addition, it was found that the residual potential rose to about 100 V during that time, and as a large number of copies were made, the image quality deteriorated.6 Effects of the Invention The electrophotographic photoreceptor of the present invention has Since the drawing layer is made of an inorganic polymer material containing zirconium and silicon, even if the photosensitive layer contains acid, it will not be affected by the ions. Therefore, even if a large number of copies are continuously copied without being affected by the environment, there will be virtually no abnormalities in image quality or electrical characteristics, resulting in extremely high reliability. .

1... Conductive/surname substrate 2...Upper bow 1st layer 3... Charge generation layer 4...Charge transport layer

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of an example of the electrophotographic photoreceptor of the present invention. DESCRIPTION OF SYMBOLS 1... Conductive substrate, 2... Undercoat layer, 3... Charge generation layer, 4... Charge transport layer. Patent applicant Fuji Xerox Co., Ltd. Agent
Patent attorney Tsuyoshi Fuchibe Figure 1 procedural amendment (voluntary) 6゜Contents of the amendment After the last line of page 12 of the detailed description section, there is a line break and the following structure is characterized by the June 28, 1999 style.

Claims (3)

[Claims] (1) An electrophotographic photoreceptor comprising an undercoat layer and a photosensitive layer on a conductive substrate, wherein the undercoat layer is made of an inorganic polymeric substance containing zirconium and silicon. Photographic photoreceptor. (2) The electrophotographic photoreceptor according to claim 1, wherein the photosensitive layer contains an acid. (3) The acid contained in the photosensitive layer is monofluoroacetic acid, difluoroacetic acid, trifluoroacetic acid, chloroacetic acid, hydrochloric acid,
The electrophotographic photoreceptor according to claim 1, which is selected from sulfuric acid and nitric acid. The electrophotographic photoreceptor according to claim 1, wherein the undercoat layer (A) is formed by applying and curing a mixed solution of a zirconium chelate compound or a zirconium alkoxide and a silane coupling agent.