JP2003186225A - Electrophotographic photoreceptor, process cartridge, and electrophotographic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photoreceptor having a negative electrification single layer which simplifies a coating process and makes the use of an electrophotographic device for the conventional layered photoreceptor possible and to provide a photoreceptor, a process cartridge and an electrophotographic device showing excellent electrophotographic characteristics without causing image defect such as irregularity in a halftone part and transfer failure while keeping electrification properties and sensitivity properties. <P>SOLUTION: In the photoreceptor having a photosensitive layer and a protective layer directly formed in this order or with a base layer interposed on a supporting body, the photoreceptor contains at least a fluorine-containing resin as a binder resin for the photosensitive layer and contains an azo pigment expressed by formula of A-(N=N-Cp)<SB>n</SB>as a charge generating material. The process cartridge and the electrophotographic device have the above photoreceptor. In the formula, A is the center skeleton and comprises substituted or unsubstituted aromatic hydrocarbon cyclic groups or heterocyclic groups which can be coupled directly or through bonding groups, Cp represents a coupler residue having a phenolic hydroxyl group, n is an integer 1 to 3, and a plurality of -N=N-Cp is not coupled at a time to one benzene ring. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an electrophotographic photoreceptor,
More specifically, the present invention relates to a process cartridge and an electrophotographic apparatus, and more specifically, an electrophotographic photoreceptor having a photosensitive layer containing a charge generating material, a hole transporting material, and a binder resin having a specific structure and a protective layer in the same layer, The present invention relates to a process cartridge having an electrophotographic photosensitive member and an electrophotographic apparatus.

[0002]

2. Description of the Related Art In recent years, organic electrophotographic photoconductors having a large degree of freedom in functional design have been used as electrophotographic photoconductors in image forming apparatuses such as copying machines, printers and facsimiles. Charge generation layer (CGL) for organic electrophotographic photoreceptors
There is known a function-separated type laminated electrophotographic photoreceptor in which a charge transport layer (CTL) and a single layer electrophotographic photoreceptor in which a charge generation material is dispersed in a medium of a charge transport material. Laminated electrophotographic photoconductors are the mainstream of practically used organic electrophotographic photoconductors, but in order to obtain a good image while keeping the balance of sensitivity and durability, the thickness of CGL is in the submicron range. Therefore, there is a disadvantage that the cost is increased because it is necessary to control the temperature of the conductive support, and when it is directly coated on the conductive support, it is easily affected by the unevenness of the support, which causes an image defect. Therefore, a single-layer electrophotographic photosensitive member in which a charge generating material and a binder resin are dispersed in the same layer is disclosed (JP-A 47-30330 and JP-A 54-16).
33, etc.). However, most of these are orthographic electrophotographic photoreceptors.

Therefore, a negative charging single-layer electrophotographic photosensitive member has been proposed in order to use the conventional apparatus used for a negative charging laminated electrophotographic photosensitive member as it is (Japanese Patent Application No. 5-348221). (Gazette etc.) It has not been put to practical use yet.

There are several factors, but compared with the laminated electrophotographic photosensitive member, for example, 1. 1. A large amount of light is required for the response. 2. When printing a large number of sheets, the charging ability decreases. 3. Image density unevenness easily occurs in the halftone area. There are problems such as poor transferability.

Further, in the single-layer electrophotographic photosensitive member, a photocurrent is generated up to a certain input light amount depending on the type and ratio of the charge generating material, charge transporting material, various additives or binder resin used. It is known that there is one (induction / high-gamma electrophotographic photoconductor) that exhibits a photo-attenuation curve having a threshold value, in which the photocurrent does not flow or is very small and the photocurrent suddenly flows out immediately after the light amount is exceeded.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a negatively charged single-layer electrophotographic photosensitive member which has a simple coating process and can be used in a conventional electrophotographic apparatus for a laminated electrophotographic photosensitive member. To do.

Another object of the present invention is to provide an electrophotographic photosensitive member, a process cartridge and an electrophotographic which exhibit excellent electrophotographic characteristics without image defects such as halftone unevenness and transfer failure while maintaining charging characteristics and sensitivity characteristics. To provide a device.

[0008]

According to the present invention, in an electrophotographic photoreceptor having a photosensitive layer and a protective layer in this order on a conductive support directly or via an underlayer, at least as a binder resin for the photosensitive layer. There is provided an electrophotographic photoreceptor having a fluororesin and containing at least an azo pigment represented by the following formula (1) as a charge generating material.

A- (N = N-Cp) _n (1) In the formula, A is a central skeleton, and is a substituted or unsubstituted aromatic hydrocarbon ring which may be bonded directly or via a bonding group. Represents a group or a heterocyclic group. Cp is a coupler residue having a phenolic hydroxyl group. n shows the integer of 1-3. However, a plurality of -N = N-Cp do not bond to the same benzene ring.

According to the present invention, there are also provided a process cartridge and an electrophotographic apparatus having the electrophotographic photosensitive member.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below.

The inventors of the present invention have conducted extensive studies to achieve the above-mentioned object, and as a result, in an electrophotographic photosensitive member having a photosensitive layer on a conductive support, the electrophotographic photosensitive member may be directly or through an undercoat layer. A surface protective layer containing a resin as a main component is provided on the single-layer type photosensitive layer characterized in that at least the charge generating material and the hole transporting material are dispersed in the resin containing the fluorine-containing resin. It turned out that the purpose was achieved.

In the present invention, the provision of the surface protective layer improves the mechanical properties such as the slipperiness of the surface and the releasability of the adherend from the surface, so that the remarkable transfer which occurs in the negatively charged single-layer electrophotographic photosensitive member. It also has the effect of preventing halftone image unevenness when printing a large number of sheets.

The resin used for the protective layer in the present invention may be one containing one or several kinds of general-purpose resins such as polycarbonate, polyester, polyarylate, polystyrene, polyethylene, polypropylene, acrylic, silicone, melamine and phenol. . Alternatively, a curable compound may be applied and then cured by heat, light, or the like, and a mixture of a general-purpose resin and a curable compound may be used. What is polymerized and cured after coating may contain an initiator and the like.

Examples of the photocurable compound include epoxy, imide and acryl, and a curable acryl monomer or oligomer having a reactive acryl group or a methacryl group is particularly preferable.

Specific examples of the photocurable acrylic monomer or oligomer used in the present invention are shown in Table 1 below, but the invention is not limited thereto.

[0017]

[Table 1]

[0018]

[Table 2]

In the case of photocuring, it is preferable to use a photoinitiator to accelerate the curing. Examples of the photoinitiator include benzophenone, Michler's ketone, thioxanthone, benzoin butyl ether, acyloxime ester and dibenzothroben. A radical initiator is preferably used in the case of performing heat curing, and examples of the usual radical initiator include, for example, P-methoxybenzoyl peroxide, m, m′-dimethoxybenzoyl peroxide, and 2,2′-azo. Bisisobutyl nitrile, 2,2 '
-Azobisisobutyric acid dimethyl ester and 4,4'-azobis-4-cyanoheptanoic acid.

Examples of the thermosetting compound include phenol resin, melamine resin and urethane resin.
Particularly, a phenol resin is preferable, and a resol type phenol resin is more preferable.

Usually, the resol type phenol resin is produced using a phenol compound and an aldehyde compound under an alkaline catalyst. The main phenols used for this are phenol, cresol, xylenol,
Examples thereof include, but are not limited to, paraalkylphenol, paraphenylphenol, resorcin and bisphenol.

The aldehydes include, but are not limited to, formaldehyde, paraformaldehyde, furfural and acetaldehyde.

Monomers of phenols, dimethylolphenols, trimethylolphenols and their mixtures, and their oligomerized products and monomers are prepared by reacting these phenols with aldehydes in the presence of an alkali catalyst. And a mixture of oligomers are made. An amine catalyst is preferably used as the alkali catalyst used at this time. As the amine-based catalyst, ammonia, hexamethylenetetramine,
Examples include, but are not limited to, trimethylamine and triethylamine. In the present invention, it is more preferable to use an amine catalyst excluding ammonia.

Further, for the purpose of controlling the electric resistance of the protective layer and preventing the increase of the residual potential in the electrophotographic photosensitive member during the repetition of the electrophotographic process, metal oxide fine particles of conductive fine particles may be contained.

The conductive metal oxide fine particles in the present invention include zinc oxide, titanium oxide, tin oxide, antimony oxide, indium oxide, bismuth oxide, tin-doped indium oxide, antimony-doped tin oxide and zirconium oxide. Is mentioned. These use only 1 type or a mixture of 2 or more types. When two or more kinds are mixed, they may be in the form of solid solution or fusion. The average particle diameter of the conductive fine particles is preferably 0.3 μm or less, more preferably 0.1 μm or less.

Fine particles of lubricant may be included for the purpose of enhancing the releasability of the surface of the protective layer. The lubricant fine particles used in the present invention may be fine particles that are incompatible with the binder resin, and among them, for example, tetrafluoroethylene resin powder, trifluorochloroethylene resin powder, hexafluoroethylene propylene resin. Fluorine resin powders such as powders, ethylene difluoride dichloride resin powders, vinylidene fluoride resin powders, and copolymers of monomers constituting these polymers; polyethylene resin powders, polypropylene resin powders, polyhexene Preferred are resin powders and polyolefin resin powders such as copolymers of monomers constituting these polymers; fluorocarbon powders and silicone powders.

The fluorine-containing resin of the binder resin for the photosensitive layer of the present invention is preferably solvent-soluble from the viewpoint of ease of production. Solvents that can be used include heptane, hexane,
Substituted or unsubstituted aliphatic hydrocarbons such as octane, cyclohexane and dichloromethane; substituted or unsubstituted aromatic hydrocarbons such as toluene, xylene and chlorobenzene; alcohols such as methanol, ethanol, butanol, propanol, amyl alcohol and methoxy propanol; Esters such as methyl acetate, ethyl acetate and butyl acetate; cellosolves such as ethyl cellosolve; chain or cyclic ethers such as diethyl ether, THF and dioxane; chain or cyclic ketones such as acetone, MEK, cyclohexanone; DMF and DMAc etc. Amides, water, a mixture thereof, and the like, but are not limited thereto.

Preferred examples of the fluorine-containing binder resin used in the photosensitive layer in the present invention include a copolymer of a polymerization active monomer and a polymerization active monomer having a carboxyl group in the molecule. Hereinafter, this example will be described.

The above-mentioned polymerization-active monomer has 2 carbon atoms such as ethylene, propylene, butene, butadiene, isoprene, pentene, hexene, heptene and octene.
~ 8 hydrocarbon-based monomers; halides of the above hydrocarbon-based monomers such as vinyl chloride, vinylidene chloride, vinyl fluoride, vinylidene fluoride, ethylene trifluoride, chloroethylene trifluoride and chloroprene; vinyl formate
Vinyl esters such as vinyl acetate, vinyl propionate, vinyl butyrate, vinyl hexylate and vinyl octylate and their halides; methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, (Meth) acrylic acid esters such as butyl (meth) acrylate, pentyl (meth) acrylate and octyl (meth) acrylate and their halides; methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, pentyl vinyl ether and Vinyl ethers such as octyl vinyl ether and halides thereof; methyl allyl ether, ethyl allyl ether, propyl allyl ether,
Allyl ethers such as butyl allyl ether and octyl allyl ether and their halides; Nitriles such as acrylonitrile, fumaronitrile and methyl butyronitrile and their halides; Maleic anhydride,
Maleic acid esters such as dimethyl maleate, diethyl maleate and dipropyl maleate; styrene, α-
Aromatic hydrocarbons such as methylstyrene and methylstyrene; and halogenated aromatic hydrocarbons such as chlorostyrene and chloromethylstyrene.

Of these, preferred are hydrocarbon-based monomers such as ethylene, propylene and butene; halogenated hydrocarbon-based monomers such as vinylidene chloride vinyl chloride, vinyl fluoride, vinylidene fluoride and ethylene trifluoride; Vinyl esters such as vinyl acetate, vinyl propionate and vinyl butyrate; (meth) ataryl acid esters such as methyl (meth) acrylate and ethyl (meth) acrylate; styrene, α-methylstyrene and methylstyrene Aromatic hydrocarbon-based compounds; and halogenated aromatic hydrocarbon-based compounds such as chlorostyrene and chloromethylstyrene, which use fluorohydrocarbon-based monomers having a fluoroethylene structure as at least one repeating unit after polymerization. Preferably.

As the carboxylic acid-containing polymerization active monomer,
(Meth) acrylic acid, maleic acid, fumaric acid, itaconic acid, styrenecarboxylic acid and the like can be mentioned. Of these, (meth) acrylic acid and maleic acid are preferable, and (meth) acrylic acid is more preferable.

Commercially available products of the fluorine-based resin used in the present invention include solvent-soluble curable fluorine having a fluoroethylene structure and a carboxyl group, such as "Cefural Coat" manufactured by Central Glass Co., Ltd. and "Lumiflon" manufactured by Asahi Glass Co., Ltd. Resins may be mentioned.

The photosensitive layer in the present invention may be, for example, a polycarbonate resin, a polyester resin, a polyarylate resin, a polystyrene resin, a polyethylene resin, a polypropylene resin, a polyurethane resin, an acrylic resin, an epoxy resin or a silicone resin, in addition to the fluorine resin. One or several known resins such as vinyl chloride resin, polyamide resin and polyimide resin may be contained.

Further, the photosensitive layer used in the present invention preferably contains a crosslinking agent used for crosslinking and curing the curable fluororesin. As the crosslinking agent, compounds having two or more active groups such as butylated melamine, methylated melamine, polyisocyanate and glyoxal are preferable. The amount of the cross-linking agent used varies depending on the curing conditions, the amount of the functional group, and the type, but it is usually used in an amount such that the functional group is equivalent or excessive.

As the charge generating material, an azo pigment represented by the following formula (1) is preferable.

A- (N = N-Cp) _n (1) In the formula, A is a substituted or unsubstituted aromatic hydrocarbon ring group or heteroatom group which may be bonded directly or via a bonding group. Indicates. Cp is a coupler residue having a phenolic hydroxyl group. n shows the integer of 1-3. However, −
N = N-Cp does not bond to the same benzene ring more than once.

The central skeleton A preferably has any of the following three types of structures,

[0038]

[Chemical 6] Among them, those having the structure of the following formula (2) are preferable,

[0039]

[Chemical 7] Particularly, those having a benzanthrone structure represented by the following formula (3) are preferable.

[0040]

[Chemical 8]

In the above formula, R ₁ represents O or C (CN) ₂ , and R
_{2 to} R ₅ are a hydrogen atom, an alkyl group such as a methyl group, an ethyl group and a propyl group, an alkoxy group such as a methoxy group, an ethoxy group and a propoxy group, a halogen group such as a fluorine atom, a chlorine atom and a bromine atom, or a cyano group. In the formula, Y represents an aromatic ring such as a substituted or unsubstituted phenyl group and naphthyl group which are bonded directly or via a bonding group.

As the coupler residue Cp, at least one of them preferably has a structure represented by the following formula (4).

[0043]

[Chemical 9]

In the formula, X represents a residue necessary for forming a polycyclic aromatic ring or a heterocyclic ring by being condensed with a benzene ring, and R ₆ and R ₇ may have a hydrogen atom or a substituent. An alkyl group,
An aryl group or a heterocyclic group is shown. Further, R ₆ and R ₇ may form a cyclic amino group via a nitrogen atom. Z represents an oxygen atom or a sulfur atom, and m is 0 or 1.

A bisazo pigment represented by the following formula (5) having the above-mentioned central skeleton and coupler component is preferable.

[0046]

[Chemical 10]

In the formula, W represents a hydrogen atom or a halogen atom, R ₈ and R ₉ represent a hydrogen atom, a halogen atom, a nitro group,
A cyano group, an alkyl group which may have a substituent, an alkoxy group, an aralkyl group, an aryl group or an alkylamino group is shown, and j and k are 1 or 2.

Specific examples of compounds of the azo pigment used in the present invention are listed in Table 2 below. Structural formula is formula (1)
Only the portions corresponding to Ar and Cp of are described. Note that n
When Cp is 2 or 3 and Cp is different, Cp1 and Cp
2, its structure is shown as Cp3.

[0049]

[Table 3]

[0050]

[Table 4]

[0051]

[Table 5]

[0052]

[Table 6]

[0053]

[Table 7]

[0054]

[Table 8]

In this electrophotographic photosensitive member, depending on the kind and amount of the charge generating material or the kind and amount of the hole transport material,
There may be a photo-attenuation curve having a dark value in which the photocurrent does not flow or is very small up to a certain input light amount, and the photocurrent suddenly flows out immediately after exceeding the light amount.

The electrophotographic photosensitive member exhibiting such potential behavior (high γ characteristic) is effective in removing noise caused by deterioration of digital signals, aberrations caused by the optical system, etc., and improving sharpness of pixels. , Which can reproduce the original digital image. Therefore, it is suitable for an electronic photograph such as a printer for outputting data of a computer, a digital copy for digitally processing an image, or the like, which needs to describe an input digital signal as a digital image.

A typical constitution of the single-layer type electrophotographic photosensitive member of the present invention is shown in FIG. The photosensitive layer is composed of a charge generation material 2 and a matrix 3 in which a hole transport material is molecularly dispersed in a binder resin. In addition, 1 is a conductive support.
The protective layer is composed of functional fine particles 4 that impart characteristics such as conductivity and slipperiness, and a binder resin 5.

Examples of the organic hole transporting material which can be used in the present invention include polycyclic aromatic compounds such as pyrene and anthracene, carbazole type, indole type, oxazole type, thiazole type, oxadiazole type and pyrazole type. , Heterocyclic compounds such as pyrazoline-based, thiadiazole-based and triazole-based compounds, hydrazone-based compounds,
A styryl compound, a benzidine compound, a triarylmethane compound, a triphenylamine compound, or a polymer having a group composed of these compounds in the main chain or side chain (for example, poly-N-vinylcarbazole or polyvinylanthracene). ) Is mentioned. In addition, these charge transport materials can be used alone or in combination of two or more.

In the photosensitive layer, if necessary, in addition to electron transporting materials represented by fluorene, quinone, diphenoquinone and anthraquinone compound derivatives, various kinds of antioxidants, sensitizers, dispersants, leveling agents and the like. You may include an additive.

As the conductive support used in the present invention, a metal plate such as aluminum, nickel, copper and stainless steel, a metal drum or a metal foil, a plastic film coated with a thin film of aluminum, tin oxide or copper iodide, or Examples thereof include glass and plastics containing conductive fine particles (for example, carbon black, silver particles and tin oxide-containing inorganic particles). It is also possible to use a support in which conductive particles are coated on a plastic, metal or alloy support together with an appropriate binder resin.

If necessary, the surface of the conductive support may be subjected to various treatments such as oxidation treatment and chemical treatment.

The present invention has the advantage that the conductive support need not be roughened. That is, when a coherent light such as a laser beam is used as a light source for exposure, in a conventional laminated electrophotographic photosensitive member including a thin film charge generation layer and a thick film charge transport layer, a conductive support and / or a charge generation layer is used. There is a problem that image defects (interference fringes) having a stripe pattern occur due to reflection of incident light from the interface with the charge transport layer. The electrophotographic photosensitive member of the present invention is a single layer type, and since the internal reflection as described above does not occur, it is not necessary to subject the surface of the conductive support to the surface roughening treatment which causes the above problems. .

Further, in the electrophotographic photosensitive member of the present invention, an undercoat layer may be provided between the photosensitive layer and the conductive support for the purpose of improving the charging property. As the material of the undercoat layer, polyvinyl alcohol, polyvinyl acetal, polyethylene oxide, ethylene cellulose, methyl cellulose,
Examples thereof include various metal chelate compounds such as polyamide, polyamic acid, polyurethane, polyimide, melamine, titanium and zirconium, and various metal alkoxides.

The photosensitive layer can be formed by dissolving the above-mentioned fluorine-containing resin in an organic solvent and applying the obtained coating liquid to a conductive support.

The thickness of the photosensitive layer of the present invention is preferably 5 to
It is 80 μm, and more preferably 8 to 40 μm.
If it is thinner than 5 μm, the charging property tends to be lowered, and if it is thicker than 80 μm, the sensitivity may be lowered. The electrophotographic photosensitive member of the present invention, a predetermined material is dissolved in an organic solvent, or a coating solution dispersed by a ball mill, ultrasonic waves, a homomixer or the like is applied onto a conductive support by dipping, blade or spraying. It is made.

A blocking layer may be provided between the protective layer and the photosensitive layer in order to prevent diffusion and leakage of charges.

Next, the electrophotographic apparatus of the present invention will be described.

FIG. 2 shows a schematic structure of an electrophotographic apparatus provided with a process cartridge having the electrophotographic photosensitive member of the present invention.

In FIG. 2, reference numeral 11 denotes a drum-shaped electrophotographic photosensitive member of the present invention, which is rotationally driven around the shaft 12 in the direction of the arrow at a predetermined peripheral speed. In the rotating process, the electrophotographic photosensitive member 11 is uniformly charged with a positive or negative predetermined potential on its peripheral surface by the primary charging unit 13, and then, an exposing unit (not shown) such as slit exposure or laser beam scanning exposure.
The exposure light 14 intensity-modulated corresponding to the time-series electric digital image signal of the target image information output from is received.
In this way, electrostatic latent images corresponding to target image information are sequentially formed on the peripheral surface of the electrophotographic photosensitive member 11.

The formed electrostatic latent image is then developed by the developing means 1.
5, the toner is developed with toner, and the electrophotographic photosensitive member 11 is provided between the electrophotographic photosensitive member 11 and the transfer unit 16 from a paper feeding unit (not shown).
Of the transfer material 17 taken out and fed in synchronization with the rotation of the
Then, the toner images formed and carried on the surface of the electrophotographic photosensitive member 11 are sequentially transferred by the transfer unit 16.

The transfer material 17 which has received the transfer of the toner image is
After being separated from the surface of the electrophotographic photosensitive member and being introduced into the image fixing means 18 to undergo image fixing, it is printed out as an image formed product (print, copy) to the outside of the apparatus.

The surface of the electrophotographic photosensitive member 11 after the image transfer is
The cleaning unit 19 removes the residual toner after transfer to make it a clean surface, and is subjected to charge elimination processing by pre-exposure light 20 from a pre-exposure unit (not shown), and then repeatedly used for image formation. If the primary charging means 13 is a contact charging means using a charging roller or the like, pre-exposure is not always necessary.

In the present invention, among the above-mentioned electrophotographic photosensitive member 11, primary charging means 13, developing means 15, cleaning means 19 and the like, a plurality of components are housed in a container and integrally combined as a process cartridge. The process cartridge may be detachably attached to the main body of the electrophotographic apparatus such as a copying machine or a laser beam printer. For example, at least one of the primary charging unit 13, the developing unit 15, and the cleaning unit 19 is integrally supported together with the electrophotographic photosensitive member 11 to form a cartridge, and the cartridge is attached to and detached from the apparatus main body by using a guide unit 22 such as a rail of the apparatus main body. The process cartridge 21 can be freely used.

When the electrophotographic apparatus is a copying machine or a printer, the exposure light 14 is reflected light or transmitted light from the original, or the original is read by a sensor and converted into a signal,
Laser beam scanning and LE performed according to this signal
The light is emitted by driving the D array, driving the liquid crystal shutter array, or the like.

The electrophotographic photoreceptor of the present invention can be used not only in electrophotographic copying machines but also in laser beam printers,
It can be widely applied to electrophotographic application fields such as CRT printers, LED printers, FAX machines, liquid crystal printers, and laser plate making.

[0076]

EXAMPLES Next, the present invention will be described in detail with reference to examples, but the embodiments of the present invention are not limited thereby. In addition, "part" in an Example shows a mass part.

Example 1 Outer diameter 30 mm, length 357.
6-66-610 on a 5mm aluminum cylinder
A solution of 5 parts of -12 quaternary polyamide copolymer resin dissolved in a mixed solvent of 70 parts of methanol / 25 parts of butanol was applied by a dipping method and then dried by heating at 90 ° C. for 10 minutes to give a film having a thickness of 0.5 μm. An intermediate layer was provided.

Next, Exemplified Compound No. P-2
10 parts of tetrahydrofuran, 150 parts of tetrahydrofuran, and 400 parts of glass beads (diameter 1 mm) were sealed in a glass container and dispersed for 6 hours with a paint shaker (manufactured by Red Devil Co.).
02B (manufactured by Central Glass) 20 parts (weight conversion after drying at 150 ° C./60 minutes), 10 parts melamine-based Uban 20HS (manufactured by Mitsui Chemicals) as a curing agent (weight conversion after drying at 150 ° C./60 minutes), the following formula ( 5 parts of the charge transport material shown in 6) and 6 parts of chlorobenzene were added, and the mixture was further dispersed for 1 hour. Then, the glass beads were removed to prepare a coating solution for the electrophotographic photosensitive member. This coating solution is applied onto the intermediate layer by dipping and then dried by heating at 150 ° C. for 60 minutes to obtain a film thickness of 1
A 7 μm photosensitive layer was prepared.

[0079]

[Chemical 11]

Next, a protective layer was formed on the photosensitive layer. Tin oxide fine particles with an average particle size of 0.02 μm (trade name: T-
1, Mitsubishi Materials Corporation 100 parts, (3, 3, 3
-Trifluoropropyl) trimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.) 30 parts, milling treatment with 95% ethanol aqueous solution 300 parts, the solution is filtered, washed with ethanol, dried, and heated at 120 ° C. for 60 minutes. , Surface treatment of the fine particles was performed.

Acrylic Monomer Exemplified Compound No. Ac
12 parts by 60 parts, tin oxide fine particles 30 subjected to the above treatment
Part, 2-methylthioxanthone 10 as a photopolymerization initiator
Parts and 300 parts of toluene were dispersed in a sand mill for 48 hours, and 60 parts of tetrafluoroethylene resin particles (trade name: Lubron L-2, manufactured by Daikin Industries, Ltd.) were mixed with the dispersion liquid, and a sand mill device was used. The coating liquid was further dispersed for 4 hours to prepare a coating liquid for the protective layer. The prepared solution is applied on the charge transport layer by a spray coating method to form a film, which is dried and then 800 mW / cm ² using a high pressure mercury lamp.
The film was cured by irradiating it with light having a light intensity of 50 seconds to form a protective layer having a film thickness of 3 μm.

The electrophotographic photosensitive member thus produced was mounted on a modified digital copying machine GP216 made by Canon. The charging conditions were a DC applied voltage of -500 V, an AC applied voltage frequency of 950 Hz, and a peak-to-peak voltage of 800.
It was set to V. When this is irradiated with laser light, the surface potential is 1 /
The exposure dose (E _1/2 ) required to attenuate to ² was 1.33 μJ / cm ² . When the EV curve is shown in FIG. 3, it has been found that it has a characteristic of abruptly reducing the potential when the amount of light exceeds a certain level.

Further, the potential at the time of whole surface exposure was set to -250 V, and an attempt was made to output a 1-dot 1-space image. Development bias frequency 1800Hz, AC component 800Vpp,
A superimposed bias of DC component −350 Vdc was applied. The optical system used is a scanner type with a resolution of 600
dpi, wavelength is 680 nm, diameter of light distribution having light intensity of 1 / e ² from peak intensity is 45 × 5 in main scanning × sub scanning.
It is 5 μm. No defect was found in the image at that time. Also, after outputting 5000 sheets, the potential at the time of whole surface exposure was similarly set to -250 V, and an output of 1 dot 1 space image was tried. No defect was found in the image at that time.

(Examples 2 to 13) Electrophotographic sensitization was performed in the same manner as in Example 1 except that the azo pigment as the charge generating material and the acrylic monomer / oligomer as the protective layer binding resin component were changed as shown in Table 3. A body was prepared and the same evaluation was performed. The results are shown in Table 3.

The electrophotographic photosensitive member produced in Example 4 was exposed while changing the laser output, and the relationship between the surface potential and the exposure amount (EV characteristic) was evaluated. The result is shown in FIG. It can be seen from this figure that it shows a light attenuation curve with a threshold.

Example 14 As a protective layer coating liquid, 4 parts of tetrafluoroethylene resin particles, 2 parts of polycarbonate resin (trade name: Z-800, manufactured by Mitsubishi Gas Chemical Co., Inc.), the above formula (6) Tetrahydrofuran (60 parts) was added to 2 parts of the charge-transporting material represented by, and spray coating was performed using a liquid dispersed for 72 hours in a sand mill, followed by drying at 100 ° C. for 30 minutes to form a surface protective layer having a thickness of 2.0 μm. Except for the above, an electrophotographic photosensitive member was produced in the same manner as in Example 1, and the same evaluation was performed. The results are shown in Table 3.

Example 15 As a protective layer coating liquid, Sn was used.
5 parts of O ₂ conductive fine particles (trade name: T-1, manufactured by Mitsubishi Materials Corp.) and polycarbonate resin (trade name: Z-
800 parts, Mitsubishi Gas Chemical Co., Inc.) 2 parts, toluene 50 parts / tetrahydrofuran 10 parts, and sand mill 72
An electrophotographic photosensitive member was prepared and evaluated in the same manner as in Example 1 except that the time-dispersed liquid was applied by dipping coating to form a surface protective layer having a film thickness of 2.0 μm. The results are shown in Table 3.

Example 16 Ac1 was used as the resin for the protective layer.
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that photocurable epoxy KR400 (manufactured by Asahi Denka Co., Ltd.) was used instead of 2, and the same evaluation was performed. The results are shown in Table 3.

(Example 17) An electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that LUMIFLON LF200 (fluorine resin, manufactured by Asahi Glass) was used as the binder resin for the photosensitive layer.
Similar evaluation was performed. The results are shown in Table 3.

Example 18 An electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that the isocyanate type Coronate T (manufactured by Nippon Polyurethane) was used as the curing agent for the photosensitive layer, and the same evaluation was carried out. It was The results are shown in Table 3.

(Example 19) An electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that the curing agent was not added and 1.5 times the amount of Sepral coat 202B was used, and the same evaluation was performed. The results are shown in Table 3.

Example 20 An electrophotographic photoreceptor was prepared in the same manner as in Example 1 except that the charge transporting material was replaced by the compound represented by the following formula, and the same evaluation was carried out. The results are shown in Table 3.

[0093]

[Chemical 12]

Example 21 An electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that the charge transporting material was replaced by the compound represented by the following formula, and the same evaluation was carried out. The results are shown in Table 3.

[0095]

[Chemical 13]

Example 22 An electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that the charge transporting material was replaced by the compound represented by the following formula, and the same evaluation was carried out. The results are shown in Table 3.

[0097]

[Chemical 14]

(Example 23) In the preparation of the photosensitive layer solution, 3,5-dimethyl-3,5'-di-t-butyl-4,
Example 1 except that 2 parts of 4'diphenoquinone were added.
An electrophotographic photosensitive member was produced in the same manner as in, and the same evaluation was performed. The results are shown in Table 3.

Example 24 Instead of the silane coupling agent of Example 1, a silicone oil (trade name: KF9) was used.
9, Shin-Etsu Silicone Co., Ltd.) and 50 parts of tin oxide fine particles treated with the same conditions as above, ethanol 18
After dispersing 0 part by a sand mill for 60 hours, tetrafluoroethylene resin particles (trade name: Lubron L) are added to the dispersion.
-2, manufactured by Daikin Industries, Ltd. (15 parts) were mixed and dispersed in a sand mill for 4 hours. Further, resol type phenol resin (trade name: PL-4804, manufactured by Gunei Chemical Co., Ltd.)
Was dissolved in 40 parts to prepare a coating liquid for the protective layer. After dipping coating this liquid, it is dried for 30 minutes at 150 ℃,
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that a surface protective layer having a film thickness of 3.0 μm was provided, and the same evaluation was performed. The results are shown in Table 3.

(Example 25) An electrophotographic photosensitive member was prepared and evaluated in the same manner as in Example 24 except that P-8 was used as the azo pigment. The results are shown in Table 3.

Comparative Example 1 An electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that the protective layer was not prepared, and the same evaluation was carried out. The results are shown in Table 3.

(Comparative Example 2) The resin for the photosensitive layer was polysulfone resin (manufactured by Teijin Amoco Engineering: Udel P17).
An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that it was replaced with (00), and the same evaluation was performed. The results are shown in Table 3.
Shown in.

[0103]

[Table 9]

(Example 26) 80 parts of zirconium acetylacetonate was dissolved in 1800 parts of tetrahydrofuran, 100 parts of butanol was added, and the undercoat layer coating solution was used to make an undercoat on an aluminum cylinder of 30 mmφ × 357.5 mm. The layer solution was applied by dip coating and dried at 110 ° C. for 10 minutes to form an undercoat layer having a film thickness of 0.2 μm.

Next, using P-13 as an azo pigment,
A photosensitive layer and a protective layer were prepared in the same manner as in Example 1 except that silicone resin fine particles (trade name: Tospearl 120, Toshiba Silicone Co., Ltd.) were used as the lubricant.

This electrophotographic photosensitive member was installed in the main body of an analog copying machine NP6030 manufactured by Canon, which was modified to have a variable light amount. After the amount of light was adjusted so that the same contrast potential as in Example 1 was obtained when the electrophotographic photosensitive member was entirely exposed, 5,000 sheets were output. A 6-point character was output before and after the durability test, and good images were obtained in all cases.

[0107]

EFFECT OF THE INVENTION The electrophotographic photoreceptor of the present invention uses a solvent-soluble fluorine-containing resin as a binder resin for a photosensitive layer, contains an azo pigment as a charge generating material, and further has a protective layer, whereby charging characteristics and sensitivity are improved. A good image without defects can be provided while maintaining the characteristics. In addition, since it operates by negative charging, it is not necessary to newly develop a peripheral technology for positive charging, and the peripheral technology used in the conventional negative charging laminated organic electrophotographic photoreceptor can be used as it is. Have.

[Brief description of drawings]

FIG. 1 is a diagram showing a layer structure of a single-layer type electrophotographic photoreceptor of the present invention.

FIG. 2 is a diagram showing an example of a schematic configuration of an electrophotographic apparatus provided with a process cartridge having the electrophotographic photosensitive member of the present invention.

FIG. 3 is a diagram showing a relationship (EV characteristic) between a surface potential and an exposure amount when the electrophotographic photosensitive member manufactured in Example 4 is exposed while changing the laser output.

[Explanation of symbols]

1 Conductive support 2 Charge generation material 3 matrix 4 Functional fine particles 5 Binder resin 11 Electrophotographic photoreceptor 12 axes 13 charging means 14 exposure light 15 Developing means 16 Transfer means 17 Transfer material 18 Fixing means 19 Cleaning means 20 Pre-exposure light 21 Process cartridge 22 Guide means

Front page continuation (51) Int.Cl. ⁷ Identification symbol FI theme code (reference) G03G 5/06 324 G03G 5/06 324A 341 341 342 342 345 345 345 346 346 348 348 350 350 350 351 351 352 352 358 356 356 360 360 360C 362 362 5/14 5/14 F Term (Reference) 2H068 AA03 AA04 AA05 AA06 AA13 AA19 AA41 BA12 BA24 BA42 BA44 BA45 BA46 BA47 BA48 BA49 BA51 BA53 BB06 BB31 BB35 BB37 BB58 CA22 CA29 CA37

Claims (26)

[Claims] 1. An electrophotographic photosensitive member having a photosensitive layer and a protective layer in this order on a conductive support directly or via an underlayer, which has at least a fluorine-containing resin as a binder resin for the photosensitive layer, and has an electric charge. An electrophotographic photoreceptor comprising at least an azo pigment represented by the following formula (1) as a generating material. A- (N = N-Cp) _n (1) (In the formula, A is a central skeleton, and may be a substituted or unsubstituted aromatic hydrocarbon ring group which may be bonded directly or via a bonding group, or Represents a heterocyclic group, Cp represents a coupler residue having a phenolic hydroxyl group, n represents an integer of 1 to 3, provided that -N = N-Cp does not bond to the same benzene ring. 2. The electrophotographic photosensitive member according to claim 1, wherein the protective layer contains a resin formed by polymerizing a curable compound. 3. The electrophotographic photosensitive member according to claim 1, wherein the protective layer contains a resin formed by polymerizing a thermosetting compound. 4. The electrophotographic photosensitive member according to claim 3, wherein the thermosetting compound is a phenol resin. 5. The electrophotographic photosensitive member according to claim 4, wherein the phenol resin is a resol type. 6. The electrophotographic photoreceptor according to claim 1, wherein the protective layer contains a resin formed by polymerizing a photocurable compound. 7. The electrophotographic photosensitive member according to claim 1, wherein the protective layer contains a resin formed by polymerizing a photocurable acrylic monomer or oligomer. 8. The electrophotographic photosensitive member according to claim 1, wherein the protective layer contains conductive metal oxide fine particles. 9. The electrophotographic photosensitive member according to claim 1, wherein the protective layer contains fine particles of a lubricant. 10. The electrophotographic photoreceptor according to claim 1, wherein the protective layer contains conductive metal oxide fine particles and lubricant fine particles. 11. The electrophotographic photosensitive member according to claim 1, wherein the central skeleton A of the charge generating material represented by the formula (1) has any one of the four types of structures shown below. . [Chemical 1] 12. The electrophotographic photosensitive member according to claim 11, wherein the central skeleton A of the charge generating material represented by the formula (1) has a structure represented by the following formula (2). [Chemical 2] (In the formula, R ₁ represents O or C (CN) ₂ , R ₃ represents a hydrogen atom, an alkyl group, an alkoxy group, a halogen group or a cyano group, and Y is bonded directly or through a bonding group. Indicates a substituted or unsubstituted aromatic ring) 13. The electrophotographic photosensitive member according to claim 12, wherein the central skeleton A of the charge generating material represented by the formula (1) has a structure represented by the following formula (3). [Chemical 3] (In the formula, R ₃ , R ₄ and R ₅ represent a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom or a cyano group) 14. At least one of the coupler residues Cp of the charge generation material represented by the formula (1) has the following formula (4):
The electrophotographic photoreceptor according to claim 1, which is a coupler residue represented by: [Chemical 4] (In the formula, X represents a residue necessary for forming a polycyclic aromatic ring or a heterocyclic ring by condensing with a benzene ring, and R ₆ and R ₇ represent a hydrogen atom or an alkyl group which may have a substituent. , An aryl group,
Indicates a complex primordium. Further, R ₆ and R ₇ may form a cyclic amino group via a nitrogen atom. Z represents an oxygen atom or a sulfur atom, and m is 0 or 1. ) 15. The electrophotographic photosensitive member according to claim 14, wherein the azo pigment is a bisazo pigment represented by the following formula (5). [Chemical 5] (In the formula, W represents a hydrogen atom or a halogen atom, R ₈ and R ₉ represent a hydrogen atom, a halogen atom, a nitro group, a cyano group, an alkyl group which may have a substituent, an alkoxy group,
It represents an aralkyl group, an aryl group or an alkylamino group, and j and k are 1 or 2. ) 16. The electrophotographic photosensitive member according to claim 1, wherein the fluororesin is soluble in a solvent. 17. The electrophotographic photosensitive member according to claim 16, wherein the fluorine-containing resin has at least a fluoroethylene structure as one of repeating units. 18. The electrophotographic photosensitive member according to claim 16, wherein the fluorine-containing resin contains a carboxyl group. 19. The electrophotographic photosensitive member according to claim 18, wherein the fluorine-containing resin is a copolymer of a polymerization active monomer and a polymerization active monomer having a carboxyl group in the molecule. 20. The electrophotographic photoreceptor according to claim 1, wherein the binder resin is a resin obtained by reacting and curing a fluorine-containing resin and a melamine-based curing agent. 21. The binder resin is a resin obtained by reacting and curing a fluorine-containing resin and an isocyanate curing agent.
21. The electrophotographic photosensitive member according to any one of 19. 22. The electrophotographic photosensitive member according to claim 1, wherein the charging system of the electrophotographic photosensitive member is negative charging. 23. The electrophotographic photosensitive member according to claim 1, which has a threshold value in a light attenuation curve of a potential upon light irradiation and is for digital light input. 24. The electrophotographic photosensitive member according to claim 1, wherein the photosensitive layer contains an organic hole transfer material. 25. The electrophotographic photosensitive member according to claim 1, wherein the electrophotographic photosensitive member is charged with a charging means, and the electrophotographic photosensitive member on which an electrostatic latent image is formed is developed with toner. Integrally supporting with at least one means selected from the group consisting of a developing means and a cleaning means for collecting the toner remaining on the electrophotographic photosensitive member after the transfer step,
A process cartridge characterized by being detachable from the main body of the electrophotographic apparatus. 26. The electrophotographic photosensitive member according to claim 1, a charging unit that charges the electrophotographic photosensitive member, and the charged electrophotographic photosensitive member is exposed to form an electrostatic latent image. An electrophotographic apparatus comprising an exposing means, a developing means for developing with a toner on an electrophotographic photoreceptor on which an electrostatic latent image is formed, and a transfer means for transferring a toner image on the electrophotographic photoreceptor onto a transfer material. .