JPH087450B2 - Method for manufacturing electrophotographic photoreceptor - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an electrophotographic photosensitive member comprising a conductive support, an undercoat layer, a charge generating layer and a charge transport layer.

[0002]

2. Description of the Related Art An electrophotographic copying machine has been developed each year with a higher speed, and a photoconductor having a high photosensitivity and a long life is required to meet the demand. In addition, in recent years, a function-separated electrophotographic photoconductor in which a photoconductor function is shared by a plurality of members is used for the purpose of improving electrophotographic properties such as charge retention properties, repetitive stability, photoresponsiveness, spectral properties, and mechanical strength. Have been proposed in many. The disadvantages of these electrophotographic photoreceptors are (1) lack of repeated stability of development contrast and environmental stability, and (2) image defects called white spots, black spots, rough spots, pinholes and the like are likely to occur. ,
(3) It has been known that the adhesive strength between the conductive support and the photosensitive layer is low, the photosensitive layer peels off during use, and the durability is insufficient.

As a measure for solving such problems, it has been attempted to provide a resin layer as an undercoat layer between the conductive support and the photosensitive layer. Examples of the resin include polyparaxylene, casein, polyvinyl alcohol, phenol resin, polyvinyl acetal resin, melamine resin, nitrocellulose, ethylene-acrylic acid copolymer, polyamide (nylon 6, nylon 66, nylon 610, copolymer nylon). , Alkoxymethylated nylon, etc.), polyurethane, gelatin, polyvinylpyrrolidone, polyvinylpyridine, polyvinylmethylether, etc. are known. It has also been proposed to form an undercoat layer by using a zirconium chelate compound, an organic zirconium compound such as zirconium alkoxide, or a silane coupling agent (see, for example, JP-A-59-223489 and JP-A-SHO). 61-94057 and JP-A-62-273549).

[0004]

By the way, when a resin layer is provided as an undercoat layer, a resin containing a relatively large amount of polar groups is used as a main component to reduce the volume resistance to such an extent that electrophotographic characteristics are not deteriorated. Although it is controlled, the volume resistance of the resin is strongly dependent on the ionic conductivity and is therefore significantly affected by temperature and humidity. Therefore, the photoconductor was placed under low temperature and low humidity or high temperature and high humidity. At this time, the resin layer becomes extremely high in resistance, which deteriorates the electrophotographic characteristics of the photosensitive layer, or the resin layer becomes extremely low in resistance, and the intended function of the resin layer is lost. Therefore, in the heretofore known resin layer, only some of the drawbacks of the photoconductor are remedied, or the effect is halved if environmental characteristics and the like are included, which is technically extremely insufficient.

On the other hand, when an organic zirconium compound such as a zirconium chelate compound, a zirconium alkoxide, or a silane coupling agent is used, the above-mentioned problems are considerably improved, but they are still not sufficient. That is, these coupling agents form a film by a thermosetting reaction, but if the curing reaction is not sufficient, a difference occurs in the wettability of the coating film surface, and the film is formed in a photosensitive layer to be laminated next, particularly a thin film. When a highly-required charge generation layer is used in a laminated manner, when the resulting coating film has an extremely uneven thickness, unevenness in the copied image,
Fog will occur. In addition, such wettability of the coating film surface changes with time, and it is very difficult to stack a charge generation layer having a uniform film thickness. As described above, the subbing layer in the conventional technique is still insufficient in terms of its effect, and it has not been possible to eliminate various drawbacks held as an electrophotographic photoreceptor, so that the characteristics of the photoreceptor are unsatisfactory. There is.

The present invention has been made in view of the above problems in the prior art. That is, an object of the present invention is to use an undercoating layer coating liquid containing an alkoxide-based coupling agent and having improved stability, whereby it is possible to suppress a change in film thickness of a charge generation layer to be laminated with time, and Another object of the present invention is to provide a method for manufacturing an electrophotographic photosensitive member that can obtain stable film thickness uniformity.

[0007]

As a result of various studies, the inventors of the present invention have found that when a coating solution containing a specific alkoxide coupling agent and a specific solvent is used as a coating solution for forming an undercoat layer. In addition, it was found that the stability of the coating solution was improved and the above-mentioned object was achieved, and the present invention was completed. A feature of the present invention is that, when an electrophotographic photosensitive member is manufactured by sequentially laminating a charge generation layer and a charge transport layer on a conductive support through an undercoat layer, the following coating liquid for forming the undercoat layer is used. Among the alkoxide-based coupling agents represented by the general formula (1), alkoxy containing zirconium
Decoupling agent and silicon-containing alkoxide system
Of coupling agents or alkoxides containing titanium
In combination with a coupling agent, these alkoxide-based
It is characterized in that a coating solution comprising a coupling agent and an aliphatic alcohol solvent having a carbon number equal to or higher than the carbon number of the alkoxy group possessed by the alkoxide coupling agent is used. _{X m -M- (OR 1) n} (1) ( wherein, R ₁ represents an alkyl group of C ₁ ~C _4, M is S
i, shows Ti or Zr, X represents an organic group, m is I 0, 1 or 2 der, a m = 4-n, n is 1 to
It is an integer of 4. )

The present invention will be described in detail below. The electrophotographic photosensitive member of the present invention is formed by sequentially coating an undercoat layer forming coating liquid, a charge generating layer forming coating liquid and a charge transport layer forming coating liquid on a conductive support. A known material can be used as the conductive support. For example, aluminum,
Stainless steel or the like can be preferably used.

The undercoat layer is formed by applying a coating liquid comprising the above alkoxide coupling agent and the above aliphatic alcohol solvent. The alkoxide coupling agent is represented by the above general formula (1). Zirco
And a silane coupling agent or
A tan coupling agent is used in combination with the tan coupling agent, and specific examples include the following.

Examples of silane coupling agents include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris-2-methoxyethoxysilane, vinyltriacetoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxy. Silane, γ-aminopropyltriethoxysilane, γ-chloropropyltrimethoxysilane, γ-2-aminoethylaminopropyltrimethylsilane, γ-mercaptopropyltrimethoxysilane, γ-ureidopropyltriethoxysilane, β-3,4 -Epoxycyclohexylethyltrimethoxysilane and the like. In addition, alkyl (phenyl) alkoxysilane and alkyl silicate can also be used.

As the titanium coupling agent, for example,
Tetrapropoxy titanium, tetrabutoxy titanium, dibutoxy titanium-bis (octylene glycolate), dipropoxy titanium-bis (ethyl acetyl acetate),
Examples include dipropoxy titanium-bis (triethanol aminate).

Examples of zirconium coupling agents include zirconium dipropoxydiacetylacetonate, tributoxyzirconium acetylacetonate and tetraalkoxyzirconium.

In the present invention, an aliphatic alcohol solvent is used as a solvent for dissolving the alkoxide coupling agent. As a solvent for dissolving the alkoxide-based coupling agent, for example, aromatic hydrocarbons such as toluene, ethyl acetate, esters such as cellosolve acetate, etc. can also be used, but it becomes cloudy when left at room temperature after liquid preparation, Since it gelates and cannot be used stably as a coating liquid, it is necessary to use an aliphatic alcohol solvent. Meanwhile, some of the aliphatic alcohol-based solvents cause a substitution reaction with the alkoxy group of the alkoxide-based coupling agent. For example, when the coating liquid for forming the undercoat layer is applied on the conductive support by a dip coating method and then dried by heating to form the undercoat layer, the substitution reaction described above is caused to cause the alkoxide-based coupling agent. The alkoxy group changes. As a result, the surface property (wettability) of the formed undercoat layer changes, and there arises a problem that the charge generation layer formed thereon cannot be uniformly formed. In order to prevent such a phenomenon, an alcohol having an alkyl group having the same number of carbon atoms or more as the alkoxy group of the alkoxide coupling agent is used, and even if the substitution reaction occurs, the alkoxide type coupling agent is used. The alkoxy group of the coupling agent may not be changed or the substitution reaction may be suppressed. Therefore, in the present invention, it is necessary to select and use an aliphatic alcohol solvent having a carbon number equal to or higher than that of the alkoxy group of the alkoxide coupling agent. In particular, an aliphatic alcohol having an alkyl group with a large steric hindrance is preferable because the substitution reaction hardly occurs. Suitable solvents for such purpose include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 1-pentanol, 2-pentanol, 3-pentanol and the like. In the invention, these are selected and used.

For the undercoat layer, the above-mentioned coating liquid for forming the undercoat layer is applied to a conductive support by, for example, a dip coating method,
It is formed by applying by a spray coating method, a blade coating method, a spinner coating method, a bead coating method, a curtain coating method, or the like, and then heating and drying. The film thickness is generally
The thickness is 0.01 to 5 μm, preferably 0.05 to 1 μm.

A photosensitive layer is provided on the undercoat layer,
In order to utilize the characteristics of the present invention, a structure in which a charge generation layer and a charge transport layer are sequentially stacked on the undercoat layer is adopted. In particular,
It is suitable when forming a uniform thin film charge generation layer.

The charge generating layer is formed by dispersing a charge generating substance in a binder resin. Examples of the charge generating substance include selenium and selenium alloys; CdS, CdSe, CdS.
Inorganic photoconductors such as Se, ZnO and ZnS; Metal or metal-free phthalocyanine pigments; Squarium compounds; Azurenium compounds; Perylene pigments; Indigo pigments; Quinacridone pigments, Polycyclic quinone pigments; Cyanine dyes; Xanthene dyes; Poly-N- Charge transfer complexes composed of vinylcarbazole and trinitrofluorenone and the like; eutectic complexes composed of a pyrylium salt dye and a polycarbonate resin, and the like.

The binder resin is well known, for example,
Polycarbonate, polystyrene, polyester, polyvinyl butyral, methacrylic acid ester polymer or copolymer, vinyl acetate polymer or copolymer, cellulose ester or ether, polybutadiene, polyurethane, epoxy resin and the like are used.

The charge transport layer is mainly composed of a charge transport material. The charge-transporting substance is not particularly limited as long as it is transparent to visible light and has a charge-transporting ability, and specific examples thereof include imidazole, pyrazoline, thiazole, oxadiazole and oxazole. , Hydrazone, ketazine, azine, carbazole, polyvinylcarbazole and the like, and derivatives thereof,
Examples thereof include triphenylamine derivatives, stilbene derivatives and benzidine derivatives. A binder resin is used in combination if necessary, and examples of the binder resin include polycarbonate, polyarylate, polyester, polystyrene, styrene-acrylonitrile copolymer, polysulfone, polymethacrylic acid ester, and styrene-methacrylic acid ester copolymer. Examples thereof include polymers.

[0019]

The present invention will be described in more detail with reference to the following examples. Example 1 Tributoxy zirconium acetylacetonate 100 parts by weight of a 50% toluene solution (ZC540, manufactured by Matsumoto Trading Co., Ltd.) γ-aminopropyl rutrimethoxysilane (A111, 11 parts by weight manufactured by Nippon Unica Co., Ltd.) n-butyl alcohol 500 parts by weight The above components were stirred with a stirrer to prepare an undercoat layer forming coating liquid. This coating solution is about 84mm in diameter and 340mm in length.
Is applied to the surface of the aluminum cylinder of No. 3 by the dip coating method, heated and dried at about 150 ° C. for 7.5 minutes, and the thickness is about 0.1
An undercoat layer of μm was formed. Next, 87 parts by weight of granular trigonal selenium and 13 parts by weight of vinyl chloride-vinyl acetate copolymer (trade name: Solution Vinyl VMCH, manufactured by Union Carbide) were added to 200 parts by weight of n-butyl acetate. The dissolved solution was dispersed for 24 hours with an attritor. Then, acetic acid was added to 30 parts by weight of the obtained dispersion.
57 parts by weight of n-butyl was added and diluted to obtain a dip coating solution. Using this dip coating solution, dip coating was performed on an undercoat layer on an aluminum cylinder at a coating speed of 110 mm / min, and 1
The charge generation layer was laminated by heating and drying at 00 ° C. for 5 minutes.
The film thickness of the charge generation layer thus obtained was set as shown in FIG. 1, and each film thickness was measured. In FIG. 1, 1 is an aluminum pipe, 2 is a charge generation layer, 3
Is an uncoated portion at both ends, and the measurement sites d ₁ , d ₂ and d
₃ is 55m from the upper end of each aluminum pipe
m, 170 mm and 285 mm positions are shown. Next, the undercoat layer coating liquid and the charge generation layer coating liquid were used to measure the change over time in the film thickness of each part of the charge generation layer (relative change in film thickness over time) in the same manner as described above. The results are shown in Table 1.

[0020] except that the type / ratio and an aliphatic alcohol solvent of Example 2-5 and Comparative Examples 1-8 alkoxide coupling agent was changed as shown in Table 1, a cylindrical aluminum in the same manner as in Example 1 Subbing layer on the surface,
The charge generation layers were sequentially stacked. Tables 1 and 2 show changes over time (relative changes in film thickness over time) of the resulting charge generation layer. The symbols in Table 1 and Table 2 are as follows. Product name Chemical name ZC540 Tributoxy zirconium acetylacetonate 50% toluene solution (Matsumoto Kosho Co., Ltd.) A1110 γ-aminopropyltriethoxysilane (Nippon Unicar Co., Ltd.) KBM503 γ-methacryloxypropyltrimethoxysilane (Shin-Etsu Chemical Co., Ltd.) ZA60 Zirconium tetra-n-butoxide (manufactured by Matsumoto trading company) ZA50 Zirconium isopropoxide (manufactured by Matsumoto trading company) TC-100 Dipropyloxytitanium acetylacetonate (manufactured by Matsumoto trading company)

[0021]

[Table 1]

[0022]

[Table 2]

[0023]

According to the present invention, the coating liquid for forming the undercoat layer has excellent stability and can be coated uniformly, and the wettability does not change during the coating operation. The film thickness of the charge generation layer laminated on can also be made uniform. Therefore, the electrophotographic photosensitive member produced by the present invention, with respect to environmental characteristics such as temperature and humidity,
It exhibits stable electrophotographic characteristics.

[Brief description of drawings]

FIG. 1 is a schematic plan view of an electrophotographic photosensitive member of the present invention.

[Explanation of symbols]

1 aluminum pipe, 2 charge generation layer, 3 both ends uncoated part

Front page continuation (72) Koji Bando 1600 Takematsu, Minamiashigara City, Kanagawa Prefecture, Fuji Xerox Co., Ltd., Takematsu Plant (72) Inventor Seiji Ashiya, 1600 Takematsu, Minami Ashigara City, Kanagawa Prefecture, Fuji Xerox Co., Ltd., Takematsu Plant ( 56) References JP-A-50-109732 (JP, A) JP-A-61-109064 (JP, A) JP-A-59-223441 (JP, A) JP-A-2-156252 (JP, A)

Claims (1)

[Claims] 1. When an electrophotographic photosensitive member is manufactured by sequentially laminating a charge generation layer and a charge transport layer on a conductive support through an undercoat layer, a coating liquid for forming an undercoat layer is generally used as follows. Alkoxide-based coupling agent represented by formula (1)
Of these, alkoxide-based couplers containing zirconium
Coupling agent and alkoxide-based coupling containing silicon
Agent or alkoxide-based coupling agent containing titanium
And alkoxide-based coupling agents
And the method for producing a photoreceptor, characterized by using a coating solution consisting of an aliphatic alcohol solvent having a carbon number number the same or more carbon alkoxy groups in the coupling agents of those alkoxide. _{X m -M- (OR 1) n} (1) ( wherein, R ₁ represents an alkyl group of C ₁ ~C _4, M is S
i, shows Ti or Zr, X represents an organic group, m is I 0, 1 or 2 der, a m = 4-n, n is 1 to
It is an integer of 4. )