JP2016188937A - Electrophotographic photoreceptor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor which is excellent in abrasion resistance and scratch resistance, has high potential stability, and suppresses occurrence of image blurring even in high humidity environment.SOLUTION: There is provided an electrophotographic photoreceptor which has a photosensitive layer and a surface layer laminated on a conductive support body in this order, where the surface layer contains a cured substance obtained by polymerization treatment of a (meth)acrylic modified phenoxy resin represented by general formula (A). In formula (A), Rand Reach independently represents a hydrogen atom, a halogen atom, an alkyl group or an aryl group; Rrepresents a hydrogen atom or a methyl group; A represents a single bond, -O-, -CRR- or -SO-; Rand Reach independently represents a hydrogen atom, an alkyl group or an aryl group; and Rand Rmay be bonded to each other to form a ring.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an electrophotographic photosensitive member used in an electrophotographic image forming apparatus.

An electrophotographic photosensitive member (hereinafter also simply referred to as “photosensitive member”) that constitutes an image forming apparatus such as an electrophotographic copying machine or a printer has a long life and the image quality stability of the formed image. Is required. In the photoconductor, the lifetime is determined as the photoconductor surface wears, and image quality deterioration is caused by minute scratches and wear unevenness formed by the photoconductor surface wear.
In recent years, as a photoreceptor that has excellent mechanical strength such as wear resistance and scratch resistance and has a long life, a photosensitive layer is laminated on a conductive support, and a hard surface layer made of a cured resin is further formed on the photosensitive layer. A photoconductor having a film formed thereon has been developed.

  For example, Patent Documents 1 to 3 disclose a surface layer made of a crosslinked resin obtained by crosslinking a modified phenoxy resin with a polyfunctional isocyanate compound.

  However, a photoreceptor containing a cross-linked resin of these modified phenoxy resins is used repeatedly, although the cross-linked resin is three-dimensionally cross-linked so that the mechanical strength of the surface layer is dramatically improved. Inferior in potential stability. This is presumably due to the presence of unreacted residual polyfunctional isocyanate compound. In the modified phenoxy resin, an unreacted hydroxyl group remains even after the crosslinking reaction, and the hydroxyl group is hydrophilic, so that it is easily affected by moisture in the atmosphere. The image will be blurred.

  On the other hand, as a photoconductor excellent in mechanical strength such as abrasion resistance and scratch resistance, Patent Document 4 and Patent Document 5 include a trifunctional or higher functional radical polymerizable monomer and a radical polymerizable charge transporting compound. A surface layer made of a cross-linked resin cured by polymerization reaction is disclosed. By using a tri- or higher functional radical polymerizable monomer, a surface layer of a highly hard crosslinked resin having a very high crosslinking density can be obtained, and further, charge transportability can be achieved by incorporating a charge transport structure. Is granted.

  However, it cannot be said that sufficient potential stability is still obtained with these photoreceptors.

Japanese Patent Laid-Open No. 7-160012 JP 7-319180 A Japanese Patent Laid-Open No. 11-95456 JP 2004-302451 A JP 2005-99688 A

  The present invention has been made on the basis of the above circumstances, and its purpose is excellent in wear resistance and scratch resistance, high potential stability, and suppression of occurrence of image blur even in a high humidity environment. An electrophotographic photosensitive member is provided.

The electrophotographic photoreceptor of the present invention is an electrophotographic photoreceptor in which a photosensitive layer and a surface layer are laminated in this order on a conductive support.
The said surface layer contains the hardened | cured material obtained by superposing | polymerizing the (meth) acryl modified phenoxy resin containing the repeating unit represented by the following general formula (A), It is characterized by the above-mentioned.

[Wherein, R ¹ and R ² each independently represents a hydrogen atom, a halogen atom, an alkyl group or an aryl group, and R ³ represents a hydrogen atom or a methyl group. A represents a single bond, —O—, —CR ⁴ R ⁵ — or —SO ₂ —, and R ⁴ and R ⁵ each independently represents a hydrogen atom, an alkyl group or an aryl group. R ⁴ and R ⁵ may combine to form a ring. ]

  In the electrophotographic photoreceptor of the present invention, it is preferable that the (meth) acryl-modified phenoxy resin further contains a repeating unit represented by the following general formula (B).

[Wherein, R ¹ and R ² each independently represents a hydrogen atom, a halogen atom, an alkyl group or an aryl group. A represents a single bond, —O—, —CR ⁴ R ⁵ — or —SO ₂ —, and R ⁴ and R ⁵ each independently represents a hydrogen atom, an alkyl group or an aryl group. R ⁴ and R ⁵ may combine to form a ring. X represents an organic group containing a silicon atom and / or a fluorine atom. ]

  According to the electrophotographic photoreceptor of the present invention, the surface layer contains a cured product obtained by polymerizing a (meth) acryl-modified phenoxy resin, so that it has excellent wear resistance and scratch resistance, and is stable in potential. In addition, image blurring is suppressed even in a high humidity environment.

1 is a cross-sectional view for explaining a configuration in an example of an image forming apparatus including a photoconductor of the present invention.

  Hereinafter, the present invention will be specifically described.

[Photoreceptor]
The photoreceptor of the present invention is an organic photoreceptor having a layer structure in which a photosensitive layer and a surface layer are sequentially laminated on a conductive support. In this photoreceptor, an intermediate layer may be provided between the conductive support and the photosensitive layer. The photosensitive layer may have a two-layer structure including a charge generation layer and a charge transport layer, or may be a single layer containing a charge generation material and a charge transport material.

  In the present invention, the organic photoreceptor means a photoreceptor having an organic compound having at least one of a charge generation function and a charge transport function that are indispensable for the constitution of the photoreceptor, and is a known organic charge generation material or organic charge transport. It is assumed to include a known organic photoreceptor such as a photoreceptor composed of a substance, a photoreceptor composed of a polymer complex with a charge generation function and a charge transport function.

[Surface layer]
The surface layer constituting the photoconductor of the present invention contains a (meth) acryl-modified phenoxy resin (hereinafter, referred to as “structural unit (A)”) containing a repeating unit represented by the general formula (A). And a cured product obtained by polymerizing “specific (meth) acryl-modified phenoxy resin” (hereinafter also referred to as “specific phenoxy cured product”). The surface layer can be formed by, for example, dispersing metal oxide fine particles in a specific phenoxy cured product.

In the general formula (A), R ¹ and R ² each independently represents a hydrogen atom, a halogen atom, or an alkyl group or aryl group optionally substituted with a fluorine atom, and R ³ represents a hydrogen atom or methyl Represents a group. A represents a single bond, —O—, —CR ⁴ R ⁵ — or —SO ₂ —, wherein R ⁴ and R ⁵ are each independently an alkyl group optionally substituted with a hydrogen atom or a fluorine atom. Or represents an aryl group. R ⁴ and R ⁵ may combine to form a ring.

Examples of the alkyl group that may be used as the group R ¹ and the group R ² include a methyl group, an ethyl group, a propyl group, and a cyclohexyl group, and the alkyl group substituted with a fluorine atom includes a trifluoromethyl group. Examples of the aryl group include a phenyl group and a benzyl group.

  As the bisphenol structural part in the structural unit (A), that is, the structural part represented by the following general formula (BP), specifically, those represented by the following formulas (BP-1) to (BP-13) Can be mentioned.

In the general formula (BP), R ^1, R ² and A are respectively R ^1, R ² and A in the formula (A) represent the same thing.

  The content ratio of the structural unit (A) in all repeating units constituting the specific (meth) acryl-modified phenoxy resin is preferably 10 mol% or more, and more preferably 30 mol% or more. When the content ratio of the structural unit (A) in all repeating units constituting the specific (meth) acryl-modified phenoxy resin is 10 mol% or more, excellent wear resistance and scratch resistance can be obtained.

  The specific (meth) acryl-modified phenoxy resin for forming the specific phenoxy cured product constituting the surface layer is a repeating unit represented by the general formula (B) (hereinafter referred to as “structural unit (B)”). It is also preferable that it further contains.

In the general formula (B), R ^1, R ² and A are respectively R ^1, R ² and A in the formula (A) represent the same thing. X represents an organic group containing a silicon atom and / or a fluorine atom (hereinafter also referred to as “Si / F-containing group”).

  According to the photoreceptor in which the surface layer is formed of a cured product obtained from such a (meth) acryl-modified phenoxy resin having a Si / F-containing group, occurrence of image blur can be extremely suppressed.

  Specific examples of the Si / F-containing group that is X in the structural unit (B) include groups represented by the following formulas (G-1) to (G-31).

  The content ratio of the structural unit (B) in all repeating units constituting the specific (meth) acryl-modified phenoxy resin is preferably 3 mol% or more and less than 90 mol%, and preferably 10 mol% or more and less than 70 mol%. More preferably. Generation | occurrence | production of an image blur can fully be suppressed because the content rate of the structural unit (B) in all the repeating units which comprise specific (meth) acryl modified phenoxy resin is 3 mol% or more. Moreover, since the content rate of the structural unit (B) in all repeating units is less than 90 mol%, the content rate of the structural unit (A) in all repeating units can fully be ensured, and it was excellent. Abrasion resistance and scratch resistance can be obtained.

  The specific (meth) acryl-modified phenoxy resin for forming a specific phenoxy cured product constituting the surface layer is a repeating unit represented by the following general formula (C) (hereinafter referred to as “structural unit (C)”). May also be included.

In the general formula (C), R ^1, R ² and A are respectively R ^1, R ² and A in the formula (A) represent the same thing. Y represents a hydrogen atom, an alkyl group, an aryl group, a heterocyclic group or an acyl group.

  In all repeating units constituting the specific (meth) acryl-modified phenoxy resin, the content of the structural unit (C) in which Y is a hydrogen atom, that is, the structural unit related to the unmodified phenoxy resin is 20 mol% or less. It is preferable. When the content of the structural unit related to the unmodified phenoxy resin in all the repeating units constituting the specific (meth) acryl-modified phenoxy resin is 20 mol% or less, the content of the hydroxyl group that is a hydrophilic group is reduced. Since it can suppress, generation | occurrence | production of the image blur in a high-humidity environment can be suppressed reliably.

Certain (meth) acrylic-modified phenoxy _{resin, -Q-CH 2 -CH (OH} ) -CH 2 - represented by the repeating units (wherein, Q is a bisphenol structure represented by the general formula (BP) The structural unit (A) is formed by substituting at least a part of the hydroxyl group present in the raw material phenoxy resin having a (meth) acryloyl group. Further, when the specific (meth) acryl-modified phenoxy resin further contains the structural unit (B), the structural unit (B) is obtained by further substituting a part of the hydroxyl group in the raw material phenoxy resin with a Si / F-containing group. ) And can be obtained thereby.
Examples of the method for substituting the hydroxyl group in the raw material phenoxy resin with a (meth) acryloyl group include a method using an acylation reaction, a reaction with an olefin compound under acidic conditions, a reaction with an isocyanate compound, and the like.
In addition, as a method for replacing the hydroxyl group in the raw material phenoxy resin with a Si / F-containing group, a method using the above reaction can be employed.

According to the photoreceptor of the present invention having a surface layer containing a specific phenoxy cured product obtained by polymerizing a specific (meth) acryl-modified phenoxy resin as described above, the photoconductor is excellent in wear resistance and scratch resistance. Further, the potential stability is high, and the occurrence of image blur is suppressed even in a high humidity environment.
This is because a specific (meth) acryl-modified phenoxy resin can be crosslinked at a polymerizable unsaturated bond site ((meth) acryloyl group) without using a compound that deteriorates electrical properties such as a polyfunctional isocyanate compound. Therefore, it is possible to increase the strength while ensuring good potential stability, and to obtain excellent wear resistance and scratch resistance. In addition, it is estimated that another reason for obtaining good potential stability is that it has a bisphenol structure similar to, for example, a polycarbonate resin or a polyarylate resin generally used as a binder resin for a charge transport layer. Is done. Furthermore, since the specific (meth) acryl-modified phenoxy resin is reduced by replacing the hydroxyl group in the raw phenoxy resin with a (meth) acryloyl group), the occurrence of image blurring in a high humidity environment is suppressed. be able to.

  In addition, according to the photoreceptor in which the specific phenoxy cured product constituting the surface layer is obtained by using a specific (meth) acryl-modified phenoxy resin containing the structural unit (B), Si / F-containing The surface energy of the surface layer can be reduced by the presence of the group, and as a result, adhesion of an ionic compound such as nitrogen oxide caused by charging or exposure to the surface layer can be suppressed.

The specific phenoxy cured product constituting the surface layer is polymerized with a specific (meth) acryl-modified phenoxy resin and, if necessary, other crosslinkable polymerizable compounds by irradiation with active rays such as ultraviolet rays and electron beams. It is obtained by being cured.
As another polymerizable compound, a monomer having two or more polymerizable functional groups (polyfunctional polymerizable compound) can be used in combination with a monomer having one polymerizable functional group (monofunctional polymerizable compound). . Specifically, examples of other polymerizable compounds include styrene monomers, acrylic monomers, methacrylic monomers, vinyl toluene monomers, vinyl acetate monomers, N-vinyl pyrrolidone monomers, and the like.

As other polymerizable compounds, an acrylic having two or more acryloyl groups (CH ₂ ═CHCO—) or methacryloyl groups (CH ₂ ═CCH ₃ CO—) can be cured with a small amount of light or in a short time. Particularly preferred are system monomers or oligomers thereof.

  Other polymerizable compounds may be used alone or in combination. In addition, these other polymerizable compounds may use monomers, but may be used after oligomerization.

  Specific examples of other polymerizable compounds are shown below.

However, in the chemical formulas showing the above exemplary compounds (M1) to (M15), R represents an acryloyl group (CH ₂ ═CHCO—), and R ′ represents a methacryloyl group (CH ₂ ═CCH ₃ CO—).

  As the other polymerizable compound, it is preferable to use a monomer having three or more polymerizable functional groups. In addition, as the other polymerizable compound, two or more kinds of compounds may be used in combination. In this case, it is preferable to use a monomer having three or more polymerizable functional groups in a proportion of 50% by mass or more. .

(Metal oxide fine particles)
The surface layer preferably contains fine metal oxide particles. Examples of the metal oxide fine particles include silica (silicon oxide), magnesium oxide, zinc oxide, lead oxide, alumina (aluminum oxide), zirconium oxide, tin oxide, titania (titanium oxide), niobium oxide, molybdenum oxide, vanadium oxide. However, from the viewpoint of electrical characteristics, it is preferable to use tin oxide.
The metal oxide fine particles are not particularly limited, and particles produced by a known production method can be used.

  The number average primary particle size of the metal oxide fine particles is preferably 1 to 300 nm, more preferably 3 to 100 nm, and still more preferably 5 to 40 nm.

  In the present invention, the number average primary particle size of the metal oxide fine particles is a photographic image obtained by taking a magnified photograph of 10,000 times with a scanning electron microscope (manufactured by JEOL Ltd.) and randomly capturing 300 particles with a scanner (aggregation). The number average primary particle size was calculated using an automatic image processing analyzer “LUZEX AP (software version Ver. 1.32)” (manufactured by Nireco Corporation).

The metal oxide fine particles may have been surface-treated with a surface treatment agent having a reactive organic group (hereinafter also referred to as “reactive organic group-containing surface treatment agent”). Specifically, raw metal oxide fine particles (hereinafter, also referred to as “untreated metal oxide fine particles”) are surface-treated with a reactive organic group-containing surface treatment agent, whereby untreated metal oxide fine particles. A reactive organic group is introduced on the surface.
The reactive organic group-containing surface treatment agent is preferably one that reacts with a hydroxy group or the like present on the surface of the untreated metal oxide fine particles. Examples of such a reactive organic group-containing surface treatment agent include silane cups. Examples thereof include a ring agent and a titanium coupling agent.
Further, as the reactive organic group-containing surface treatment agent, it is preferable to use a surface treatment agent having a radical polymerizable reactive group. Examples of the radical polymerizable reactive group include a vinyl group, an acryloyl group, and a methacryloyl group. Such a radical polymerizable reactive group can react with the polymerizable compound according to the present invention to form a strong surface layer. As the surface treatment agent having a radical polymerizable reactive group, a silane coupling agent having a radical polymerizable reactive group such as a vinyl group, an acryloyl group, or a methacryloyl group is preferable.

  Specific examples of the reactive organic group-containing surface treatment agent are shown below.

_{S-1: CH 2 = CHSi} (CH 3) (OCH 3) 2
_{S-2: CH 2 = CHSi} (OCH 3) 3
S-3: CH ₂ = CHSiCl _{3
S-4: CH 2 = CHCOO} (CH 2) 2 Si (CH 3) (OCH 3) 2
_{S-5: CH 2 = CHCOO} (CH 2) 2 Si (OCH 3) 3
_{S-6: CH 2 = CHCOO} (CH 2) 2 Si (OC 2 H 5) (OCH 3) 2
_{S-7: CH 2 = CHCOO} (CH 2) 3 Si (OCH 3) 3
_{S-8: CH 2 = CHCOO} (CH 2) 2 Si (CH 3) Cl 2
_{S-9: CH 2 = CHCOO} (CH 2) 2 SiCl 3
_{S-10: CH 2 = CHCOO} (CH 2) 3 Si (CH 3) Cl 2
S-11: CH ₂ = CHCOO (CH ₂ ) ₃ SiCl _{3
S-12: CH 2 = C} (CH 3) COO (CH 2) 2 Si (CH 3) (OCH 3) 2
_{S-13: CH 2 = C} (CH 3) COO (CH 2) 2 Si (OCH 3) 3
_{S-14: CH 2 = C} (CH 3) COO (CH 2) 3 Si (CH 3) (OCH 3) 2
_{S-15: CH 2 = C} (CH 3) COO (CH 2) 3 Si (OCH 3) 3
_{S-16: CH 2 = C} (CH 3) COO (CH 2) 2 Si (CH 3) Cl 2
_{S-17: CH 2 = C} (CH 3) COO (CH 2) 2 SiCl 3
_{S-18: CH 2 = C} (CH 3) COO (CH 2) 3 Si (CH 3) Cl 2
_{S-19: CH 2 = C} (CH 3) COO (CH 2) 3 SiCl 3
_{S-20: CH 2 = CHSi} (C 2 H 5) (OCH 3) 2
_{S-21: CH 2 = C} (CH 3) Si (OCH 3) 3
_{S-22: CH 2 = C} (CH 3) Si (OC 2 H 5) 3
_{S-23: CH 2 = CHSi} (OCH 3) 3
_{S-24: CH 2 = C} (CH 3) Si (CH 3) (OCH 3) 2
_{S-25: CH 2 = CHSi} (CH 3) Cl 2
_{S-26: CH 2 = CHCOOSi} (OCH 3) 3
_{S-27: CH 2 = CHCOOSi} (OC 2 H 5) 3
_{S-28: CH 2 = C} (CH 3) COOSi (OCH 3) 3
_{S-29: CH 2 = C} (CH 3) COOSi (OC 2 H 5) 3
_{S-30: CH 2 = C} (CH 3) COO (CH 2) 3 Si (OC 2 H 5) 3
_{S-31: CH 2 = CHCOO} (CH 2) 2 Si (CH 3) 2 (OCH 3)
_{S-32: CH 2 = CHCOO} (CH 2) 2 Si (CH 3) (OCOCH 3) 2
_{S-33: CH 2 = CHCOO} (CH 2) 2 Si (CH 3) (ONHCH 3) 2
_{S-34: CH 2 = CHCOO} (CH 2) 2 Si (CH 3) (OC 6 H 5) 2
_{S-35: CH 2 = CHCOO} (CH 2) 2 Si (C 10 H 21) (OCH 3) 2
_{S-36: CH 2 = CHCOO} (CH 2) 2 Si (CH 2 C 6 H 5) (OCH 3) 2

  Moreover, as a reactive organic group containing surface treating agent, you may use the silane compound which has a reactive organic group in which radical polymerization is possible other than what is shown to the said exemplary compound (S-1)-(S-36). .

  The reactive organic group-containing surface treatment agent may be used alone or in combination of two or more.

  It is preferable that the usage-amount of a reactive organic group containing surface treating agent is 0.1-200 mass parts with respect to 100 mass parts of untreated metal oxide fine particles, More preferably, it is 7-70 mass parts.

  Examples of the treatment method for the untreated metal oxide fine particles of the reactive organic group-containing surface treatment agent include, for example, a slurry containing untreated metal oxide fine particles and a reactive organic group-containing surface treatment agent (suspension of solid particles). The method of wet crushing is mentioned. By this method, re-aggregation of the untreated metal oxide fine particles is prevented, and at the same time, the surface treatment of the untreated metal oxide fine particles proceeds. Thereafter, the solvent is removed to form powder.

  Examples of the surface treatment apparatus include a wet media dispersion type apparatus. In this wet media dispersion type device, beads are filled as a medium in a container, and agitation disk mounted perpendicular to the rotation axis is rotated at high speed to crush and pulverize agglomerated particles of untreated metal oxide fine particles. It is an apparatus having a step of dispersing, and the structure thereof is not limited as long as the untreated metal oxide fine particles are sufficiently dispersed and surface treated when performing surface treatment on the untreated metal oxide fine particles. For example, various types such as a vertical type, a horizontal type, a continuous type, and a batch type can be adopted. Specifically, a sand mill, ultra visco mill, pearl mill, glen mill, dyno mill, agitator mill, dynamic mill and the like can be used. These dispersion-type devices are finely pulverized and dispersed by impact crushing, friction, shearing, shear stress, etc., using a grinding medium (media) such as balls and beads.

  As beads used in the wet media dispersion type apparatus, balls made of glass, alumina, zircon, zirconia, steel, flint stone, etc. can be used, but those made of zirconia or zircon are particularly preferable. Further, as the size of the beads, those having a diameter of about 1 to 2 mm are usually used, but in the present invention, those having a diameter of about 0.1 to 1.0 mm are preferably used.

  Various materials such as stainless steel, nylon and ceramic can be used for the disk and container inner wall used in the wet media dispersion type apparatus. In the present invention, the disk and container inner wall made of ceramic such as zirconia or silicon carbide are particularly used. Is preferred.

  Other components may be contained in the surface layer. For example, a charge transport agent and various antioxidants can be contained, and various lubricant particles can be added. As the lubricant particles, for example, fluorine atom-containing resin particles can be added. Examples of the fluorine atom-containing resin particles include tetrafluoroethylene resin, trifluorinated ethylene chloride resin, hexafluoroethylene chloride propylene resin, vinyl fluoride resin, vinylidene fluoride resin, ethylene difluoride dichloride resin, and these The copolymer is preferably made of one or two or more selected from copolymers, but is particularly preferably made of a tetrafluoroethylene resin or a vinylidene fluoride resin.

  The layer thickness of the surface layer is preferably 0.2 to 10 μm, more preferably 0.5 to 6 μm.

  Hereinafter, the structure of the photoreceptor other than the surface layer will be described.

[Conductive support]
The conductive support only needs to have conductivity, for example, a metal such as aluminum, copper, chromium, nickel, zinc and stainless steel formed into a drum or a sheet, or a metal foil such as aluminum or copper. Examples include those laminated on plastic films, aluminum, indium oxide, tin oxide, etc. deposited on plastic films, metals with conductive layers applied alone or with a binder resin, plastic films and paper .

[Middle layer]
In the photoreceptor, an intermediate layer having a barrier function and an adhesive function may be provided between the conductive support and the organic photosensitive layer. In consideration of various failure prevention, it is preferable to provide an intermediate layer.

  Such an intermediate layer contains, for example, a binder resin (hereinafter also referred to as “binder resin for intermediate layer”) and, if necessary, conductive particles and metal oxide particles.

  Examples of the intermediate layer binder resin include casein, polyvinyl alcohol, nitrocellulose, ethylene-acrylic acid copolymer, polyamide resin, polyurethane resin, and gelatin. Among these, alcohol-soluble polyamide resins are preferable.

The intermediate layer can contain various conductive particles and metal oxide particles for the purpose of adjusting the resistance. For example, various metal oxide particles such as alumina, zinc oxide, titanium oxide, tin oxide, antimony oxide, indium oxide, and bismuth oxide can be used. Ultrafine particles such as indium oxide doped with tin, tin oxide doped with antimony, and zirconium oxide can be used.
The number primary average particle diameter of such metal oxide particles is preferably 0.3 μm or less, more preferably 0.1 μm or less.

  These metal oxide particles may be used alone or in combination of two or more. When two or more kinds are mixed, it may take the form of a solid solution or fusion.

  The content ratio of the conductive particles or metal oxide particles is preferably 20 to 400 parts by mass, more preferably 50 to 350 parts by mass with respect to 100 parts by mass of the intermediate layer binder resin.

  The thickness of the intermediate layer is preferably 0.1 to 15 μm, more preferably 0.3 to 10 μm.

(Charge generation layer)
The charge generation layer in the organic photosensitive layer contains a charge generation material and a binder resin (hereinafter also referred to as “binder resin for charge generation layer”).

  Examples of charge generation materials include azo raw materials such as Sudan Red and Diane Blue, quinone pigments such as pyrenequinone and anthanthrone, quinocyanine pigments, perylene pigments, indigo pigments such as indigo and thioindigo, pyranthrone and diphthaloylpyrene. Examples thereof include, but are not limited to, ring quinone pigments and phthalocyanine pigments. Among these, polycyclic quinone pigments and titanyl phthalocyanine pigments are preferable. These charge generation materials may be used alone or in combination of two or more.

  As the binder resin for the charge generation layer, known resins can be used. For example, polystyrene resin, polyethylene resin, polypropylene resin, acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, polyvinyl butyral resin, epoxy resin, Polyurethane resins, phenol resins, polyester resins, alkyd resins, polycarbonate resins, silicone resins, melamine resins, and copolymer resins containing two or more of these resins (eg, vinyl chloride-vinyl acetate copolymer resins, chlorides) Vinyl-vinyl acetate-maleic anhydride copolymer resin), poly-vinylcarbazole resin, and the like, but are not limited thereto. Among these, polyvinyl butyral resin is preferable.

  The content ratio of the charge generation material in the charge generation layer is preferably 1 to 600 parts by mass, more preferably 50 to 500 parts by mass with respect to 100 parts by mass of the binder resin for charge generation layer.

  The layer thickness of the charge generation layer varies depending on the characteristics of the charge generation material, the characteristics of the binder resin for the charge generation layer, the content ratio, etc., but is preferably 0.01 to 5 μm, more preferably 0.05 to 3 μm. is there.

(Charge transport layer)
The charge transport layer in the organic photosensitive layer contains a charge transport agent and a binder resin (hereinafter also referred to as “binder resin for charge transport layer”).

  Examples of the charge transporting agent contained in the charge transporting layer include substances that transport charges (holes), such as triphenylamine derivatives, hydrazone compounds, styryl compounds, benzidine compounds, and butadiene compounds.

  The charge transport agent contained in the charge transport layer may be the same as or different from the charge transport agent contained in the surface layer.

  A known resin can be used as the binder resin for the charge transport layer. Polycarbonate resin, polyacrylate resin, polyester resin, polystyrene resin, styrene-acrylonitrile copolymer resin, polymethacrylic ester resin, styrene-methacrylic ester Examples of the resin include a copolymer resin, and a polycarbonate resin is preferable. Furthermore, BPA (bisphenol A) type, BPZ (bisphenol Z) type, dimethyl BPA type, BPA-dimethyl BPA copolymer type polycarbonate resin and the like are preferable in terms of crack resistance, wear resistance, and charging characteristics.

  The content ratio of the charge transport agent in the charge transport layer is preferably 10 to 500 parts by weight, more preferably 20 to 250 parts by weight with respect to 100 parts by weight of the charge transport layer binder resin.

  The layer thickness of the charge transport layer varies depending on the characteristics of the charge transport agent, the characteristics and the content ratio of the binder resin for the charge transport layer, but is preferably 5 to 40 μm, more preferably 10 to 30 μm.

  In the charge transport layer, an antioxidant, an electronic conductive agent, a stabilizer, silicone oil, or the like may be added. As the antioxidant, those disclosed in JP-A No. 2000-305291 and as the electronic conductive agent are disclosed in JP-A Nos. 50-137543 and 58-76483.

[Method for producing photoreceptor]
Specifically, such a photoreceptor can be produced through the following steps.
Process (1): The process of forming an intermediate | middle layer by apply | coating the coating liquid for intermediate | middle layer formation to the outer peripheral surface of an electroconductive support body, and drying.
Step (2): A step of forming a charge generation layer by applying a coating solution for forming a charge generation layer on the outer peripheral surface of an intermediate layer formed on a conductive support and drying it.
Step (3): A step of forming a charge transport layer by applying a coating liquid for forming a charge transport layer to the outer peripheral surface of the charge generation layer formed on the intermediate layer and drying.
Step (4): A step of forming a surface layer by applying a coating solution for forming a surface layer to the outer peripheral surface of the charge transport layer formed on the charge generation layer, polymerizing and curing.

[Step (1): Formation of intermediate layer]
The intermediate layer is prepared by dissolving the binder resin for the intermediate layer in a solvent to prepare a coating liquid (hereinafter also referred to as “intermediate layer forming coating liquid”), and if necessary, conductive particles and metal oxide particles. After the dispersion, the coating solution can be formed on the conductive support in a certain film thickness to form a coating film, and the coating film can be dried.
Examples of the coating method for the intermediate layer forming coating solution include known dip coating methods, spray coating methods, spinner coating methods, bead coating methods, blade coating methods, beam coating methods, slide hopper methods, circular slide hopper methods, and the like. A method is mentioned.
The method for drying the coating film can be appropriately selected according to the type of solvent and the film thickness, but thermal drying is preferred.

  The solvent used in the intermediate layer forming step is preferably a solvent in which conductive fine particles and metal oxide particles are well dispersed and an intermediate layer binder resin, particularly a polyamide resin is dissolved. Specifically, alcohols having 1 to 4 carbon atoms such as methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n-butanol, t-butanol, sec-butanol are excellent in solubility and coating performance of polyamide resin. preferable. In addition, examples of co-solvents that can be used in combination with the above-described solvent to improve storage stability and particle dispersibility and obtain a preferable effect include benzyl alcohol, toluene, methylene chloride, cyclohexanone, and tetrahydrofuran.

  The concentration of the binder resin for the intermediate layer in the coating liquid for forming the intermediate layer is appropriately selected according to the thickness of the intermediate layer and the production rate.

  As a means for dispersing the conductive particles and metal oxide particles, an ultrasonic disperser, a ball mill, a sand mill, a homomixer, or the like can be used, but is not limited thereto.

[Step (2): Formation of Charge Generation Layer]
The charge generation layer is prepared by dispersing a charge generation material in a solution in which a charge generation layer binder resin is dissolved in a solvent to prepare a coating solution (hereinafter also referred to as “charge generation layer forming coating solution”). The coating solution can be formed on the intermediate layer by coating the intermediate layer with a certain film thickness to form a coating film and then drying the coating film.
As a coating method for the charge generation layer forming coating solution, for example, dip coating method, spray coating method, spinner coating method, bead coating method, blade coating method, beam coating method, slide hopper method, circular slide hopper method and the like are known. The method is mentioned.
The method for drying the coating film can be appropriately selected according to the type of solvent and the film thickness, but thermal drying is preferred.

  Examples of the solvent used for forming the charge generation layer include toluene, xylene, methylene chloride, 1,2-dichloroethane, methyl ethyl ketone, cyclohexane, ethyl acetate, t-butyl acetate, methanol, ethanol, propanol, butanol, methyl cellosolve, Examples include, but are not limited to, 4-methoxy-4-methyl-2-pentanone, ethyl cellosolve, tetrahydrofuran, 1-dioxane, 1,3-dioxolane, pyridine, and diethylamine.

  As a means for dispersing the charge generating substance, for example, an ultrasonic disperser, a ball mill, a sand mill, a homomixer, or the like can be used, but is not limited thereto.

[Step (3): Formation of Charge Transport Layer]
The charge transport layer is prepared by preparing a coating solution in which a charge transport layer binder resin and a charge transport agent are dissolved in a solvent (hereinafter also referred to as “charge transport layer forming coating solution”), and generating a charge from the coating solution. It can form by apply | coating to a fixed film thickness on a layer, forming a coating film, and drying the said coating film.
As a coating method of the coating solution for forming the charge transport layer, for example, dip coating method, spray coating method, spinner coating method, bead coating method, blade coating method, beam coating method, slide hopper method, circular slide hopper method and the like are known. The method is mentioned.
The method for drying the coating film can be appropriately selected according to the type of solvent and the film thickness, but thermal drying is preferred.

  Examples of the solvent used for forming the charge transport layer include toluene, xylene, methylene chloride, 1,2-dichloroethane, methyl ethyl ketone, cyclohexanone, ethyl acetate, butyl acetate, methanol, ethanol, propanol, butanol, tetrahydrofuran, and 1,4. -Dioxane, 1,3-dioxolane, pyridine, diethylamine and the like are exemplified, but not limited thereto.

[Step (4): Formation of surface layer]
The surface layer is formed by adding a specific (meth) acryl-modified phenoxy resin, a polymerization initiator, if necessary, metal oxide fine particles, other polymerizable compounds, and other components to a known solvent and applying a coating solution (hereinafter referred to as “the coating liquid”). (Also referred to as “surface layer forming coating solution”), and coating the surface layer forming coating solution on the outer peripheral surface of the charge transport layer formed in step (3) to form a coating film. By drying the film and polymerizing and curing specific polymerizable components such as (meth) acryl-modified phenoxy resin and other polymerizable compounds in the coating film by irradiating with active rays such as ultraviolet rays and electron beams A specific phenoxy cured product can be obtained, whereby a surface layer can be formed.

  As a means for dispersing the metal oxide fine particles in the surface layer forming coating solution, an ultrasonic disperser, a ball mill, a sand mill, a homomixer, or the like can be used, but is not limited thereto.

  As the solvent used for forming the surface layer, any solvent can be used as long as the polymerizable compound and the metal oxide fine particles can be dissolved or dispersed. For example, methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n- Butanol, t-butanol, sec-butanol, benzyl alcohol, toluene, xylene, methylene chloride, methyl ethyl ketone, cyclohexane, ethyl acetate, butyl acetate, methyl cellosolve, ethyl cellosolve, tetrahydrofuran, 1-dioxane, 1,3-dioxolane, pyridine and Although diethylamine etc. are mentioned, it is not limited to these.

  As a coating method of the surface layer forming coating solution, for example, known methods such as dip coating method, spray coating method, spinner coating method, bead coating method, blade coating method, beam coating method, slide hopper method, circular slide hopper method, etc. A method is mentioned.

  The coating film may be cured without being dried, but it is preferable to perform the curing treatment after natural drying or heat drying.

  Drying conditions can be appropriately selected depending on the type of solvent, film thickness, and the like. The drying temperature is preferably room temperature to 180 ° C, particularly preferably 80 to 140 ° C. The drying time is preferably 1 minute to 200 minutes, and particularly preferably 5 minutes to 100 minutes.

  As a method of reacting a polymerizable component such as a specific (meth) acryl-modified phenoxy resin or other polymerizable compound, a method of reacting by electron beam cleavage, a radical polymerization initiator is added, and a reaction is performed by light or heat. The method etc. are mentioned. As the radical polymerization initiator, either a photopolymerization initiator or a thermal polymerization initiator can be used. A photopolymerization initiator and a thermal polymerization initiator can also be used in combination.

  As the radical polymerization initiator, a photopolymerization initiator is preferable, and among them, an alkylphenone compound or a phosphine oxide compound is preferable. In particular, a compound having an α-hydroxyacetophenone structure or an acylphosphine oxide structure is preferable.

  The polymerization initiators may be used alone or in combination of two or more.

  The addition ratio of the polymerization initiator is preferably 0.1 to 20 parts by mass, more preferably 0.5 to 10 parts by mass with respect to 100 parts by mass of all polymerizable components for forming a specific phenoxy cured product. Part.

  A specific phenoxy-cured product is produced by irradiating the coating with actinic radiation as a curing treatment, generating radicals, polymerizing, and curing by forming cross-linking bonds between molecules and within the molecules. The As the actinic radiation, ultraviolet rays and electron beams are more preferred, and ultraviolet rays are particularly preferred because they are easy to use.

As the ultraviolet light source, any light source that generates ultraviolet light can be used without limitation. For example, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a carbon arc lamp, a metal halide lamp, a xenon lamp, a flash (pulse) xenon, or the like can be used.
Irradiation conditions vary depending on each lamp, but the irradiation amount of active rays is usually 5 to 500 mJ / cm ² , preferably 5 to 100 mJ / cm ² .
The power of the lamp is preferably 0.1 kW to 5 kW, particularly preferably 0.5 kW to 3 kW.

  As an electron beam source, there is no particular limitation on the electron beam irradiation apparatus, and generally, an electron beam accelerator for electron beam irradiation is a curtain beam type that is relatively inexpensive and can provide a large output. Used. The acceleration voltage during electron beam irradiation is preferably 100 to 300 kV. The absorbed dose is preferably 0.5 to 10 Mrad.

  The irradiation time for obtaining the necessary amount of active ray irradiation is preferably 0.1 second to 10 minutes, and more preferably 0.1 second to 5 minutes from the viewpoint of work efficiency.

  In the step of forming the surface layer, drying can be performed before and after irradiation with active rays and during irradiation with active rays, and the timing of drying can be appropriately selected by combining these.

[Image forming apparatus]
FIG. 1 is an explanatory cross-sectional view illustrating a configuration in an example of an image forming apparatus including the photosensitive member of the present invention.
This image forming apparatus is called a tandem type color image forming apparatus, and includes four sets of image forming units 10Y, 10M, 10C, and 10Bk, an intermediate transfer body unit 7, a paper feeding means 21, and a fixing means 24. Become. A document image reading device SC is disposed on the upper part of the main body A of the image forming apparatus.

The four sets of image forming units 10Y, 10M, 10C, and 10Bk are arranged along the rotation direction of the photoreceptors 1Y, 1M, 1C, and 1Bk in the outer peripheral surface area of the rotating drum-shaped photoreceptors 1Y, 1M, 1C, and 1Bk. The charging unit 2Y, 2M, 2C, 2Bk, the exposure unit 3Y, 3M, 3C, 3Bk, the developing unit 4Y, 4M, 4C, 4Bk, and the primary transfer rollers 5Y, 5M, 5C, 5Bk are sequentially arranged. The primary transfer unit and the cleaning units 6Y, 6M, 6C, and 6Bk are included.
In this image forming apparatus, a photoreceptor having a surface layer containing the above-described specific phenoxy cured product is used as the photoreceptors 1Y, 1M, 1C, and 1Bk.

  The image forming units 10Y, 10M, 10C, and 10Bk have the same configuration except that the colors of the toner images formed on the photoreceptors 1Y, 1M, 1C, and 1Bk are different from yellow, magenta, cyan, and black, respectively. Hereinafter, the image forming unit 10Y will be described in detail as an example.

  The charging unit 2Y is a unit that applies a uniform potential to the photoreceptor 1Y to charge the surface of the photoreceptor 1Y. In this example, a corona discharge type charger is used.

  The exposure unit 3Y is a unit that performs exposure based on an image signal (yellow) on the photoreceptor 1Y to which a uniform potential is applied by the charging unit 2Y, and forms an electrostatic latent image corresponding to a yellow image. As the exposure means 3Y, an exposure apparatus constituted by LEDs and light-emitting elements arranged in an array in the axial direction of the photoreceptor 1Y and an imaging element, or an exposure apparatus using a laser optical system or the like is used. .

  The developing means 4Y is a means for supplying toner onto the exposed photoreceptor 1Y to form a toner image. For example, a developing sleeve that contains a magnet and holds the developer and rotates, and the photoreceptor 1Y and this developing means. It comprises a voltage application device for applying a direct current and / or alternating current bias voltage between the sleeve and the sleeve.

  The primary transfer roller 5Y is a means for transferring the toner image formed on the photoreceptor 1Y to the intermediate transfer body 70 having an endless belt shape, and is disposed so as to contact the intermediate transfer body 70.

  The cleaning unit 6Y is a unit that cleans untransferred toner remaining on the photoreceptor 1Y after transfer, and includes, for example, a cleaning blade and a brush roller provided upstream of the cleaning blade.

  The fixing unit 24 is, for example, a heat roller fixing configured by a heating roller having a heating source therein and a pressure roller provided in pressure contact with the heating roller so as to form a fixing nip portion. One of the methods is mentioned.

  In this image forming apparatus, among the image forming unit 10Y, the photosensitive member 1Y, the charging unit 2Y, the developing unit 4Y, and the cleaning unit 6Y are integrally supported and provided as a process cartridge. The process cartridge is a rail or the like. You may be comprised so that attachment or detachment with respect to the apparatus main body A is possible via a guide means.

  The image forming units 10Y, 10M, 10C, and 10Bk are arranged in tandem in the vertical direction, and the intermediate transfer body unit 7 is arranged on the left side of the photoconductors 1Y, 1M, 1C, and 1Bk in the drawing. The intermediate transfer body unit 7 is wound around a plurality of rollers 71, 72, 73, 74, and is supported by a semiconductive endless belt-like intermediate transfer body 70, and the inside of the intermediate transfer body 70. The primary transfer rollers 5Y, 5M, 5C, 5Bk and the secondary transfer roller 5b, and the cleaning means 6b.

  The process cartridges of the image forming units 10Y, 10M, 10C, and 10Bk and the intermediate transfer body unit 7 are housed in a housing 8, and the housing 8 is pulled out from the apparatus main body A through support rails 82L and 82R. It is configured to be possible.

  In the image forming apparatus configured as described above, a toner image is formed by the image forming units 10Y, 10M, 10C, and 10Bk. Specifically, first, the surface of the photoreceptors 1Y, 1M, 1C, 1Bk is uniformly negatively charged by the discharge by the charging means 2Y, 2M, 2C, 2Bk. Next, the surfaces of the photoreceptors 1Y, 1M, 1C, and 1Bk are exposed based on the image signal by the exposure means 3Y, 3M, 3C, and 3Bk, and an electrostatic latent image is formed. Further, the developing means 4Y, 4M, 4C, and 4Bk supply toner charged with the same polarity as the electrostatic latent image to the surface of the photoreceptors 1Y, 1M, 1C, and 1Bk, whereby the electrostatic latent image is visualized. To form a toner image of each color. Thereafter, the toner images of the respective colors are sequentially transferred and superimposed on the intermediate transfer body 70 that is circulated by applying a transfer current from the primary transfer rollers 5Y, 5M, 5C, and 5Bk, thereby forming a color toner image. Is done. Thereafter, a transfer material (image support for carrying a fixed final image: for example, plain paper, transparent sheet, etc.) P housed in the paper feed cassette 20 is fed by the paper feed means 21 and a plurality of intermediate rollers 22A. , 22B, 22C, 22D and the registration roller 23, and then conveyed to the secondary transfer roller 5b. Then, the secondary transfer roller 5 b is brought into contact with the intermediate transfer body 70, and the color toner images are collectively transferred onto the transfer material P. Thereafter, the transfer material P onto which the color toner image has been transferred is separated at a portion of the intermediate transfer body 70 where the curvature is high, conveyed to the fixing unit 24, fixed by the fixing unit 24, and sandwiched between the paper discharge rollers 25. And placed on a paper discharge tray 26 outside the apparatus.

On the other hand, the photoreceptors 1Y, 1M, 1C, and 1Bk after the toner images of the respective colors are transferred to the intermediate transfer member 70 by the primary transfer rollers 5Y, 5M, 5C, and 5Bk are cleaned by the cleaning means 6Y, 6M, 6C, and 6Bk. The remaining toner is removed.
Further, after the color toner image is transferred to the transfer material P by the secondary transfer roller 5b, the residual toner is removed by the cleaning unit 6b from the intermediate transfer body 70 from which the transfer material P is separated by curvature.

During the image forming process, the primary transfer roller 5Bk is always in contact with the photoconductor 1Bk, and the other primary transfer rollers 5Y, 5M, and 5C are respectively corresponding to the photoconductors 1Y and 1M only when a color toner image is formed. , 1C.
Further, the secondary transfer roller 5b is brought into contact with the intermediate transfer member 70 only when the secondary transfer is performed.

  In FIG. 1, the image forming apparatus of the present invention is shown as a color laser printer. However, the image forming apparatus of the present invention may be configured as a monochrome laser printer or a copy.

〔toner〕
The toner used in the image forming apparatus of the present invention may be a pulverized toner or a polymerized toner, but the image forming apparatus of the present invention is produced by a polymerization method from the viewpoint of obtaining a high quality image. It is preferable to use the polymerized toner.
As the toner, it is preferable to use a toner in which the binder resin is made of a crystalline resin. By using a toner containing a binder resin made of a crystalline resin, it is possible to suppress the occurrence of fog in the obtained image. This is considered to be due to the reduction in charging variation when the toner is frictionally charged in the developing means 4Y, 4M, 4C, and 4Bk.

  The volume average particle diameter of the toner, that is, the 50% volume particle diameter (Dv50) is preferably 2 to 8 μm, more preferably 3 to 7 μm. By setting this range, the resolution can be increased.

  The toner according to the present invention may be used alone as a one-component developer, or may be mixed with a carrier and used as a two-component developer.

  When used as a one-component developer, a non-magnetic one-component developer or a magnetic one-component developer containing about 0.1 to 0.5 μm of magnetic particles in the toner can be used. be able to.

  In addition, when used as a two-component developer by mixing with a carrier, conventionally known magnetic particles of the carrier, such as metals such as iron, ferrite, and magnetite, alloys of these metals with metals such as aluminum and lead, etc. Materials can be used, and ferrite particles are particularly preferable. The magnetic particles preferably have a volume average particle size of 15 to 100 μm, more preferably 25 to 80 μm.

  The volume average particle diameter of the carrier can be typically measured by a laser diffraction particle size distribution measuring apparatus “HELOS” (manufactured by SYMPATEC) equipped with a wet disperser.

  The carrier is preferably a carrier in which magnetic particles are further coated with a resin, or a so-called resin dispersion type carrier in which magnetic particles are dispersed in a resin. The resin composition for coating is not particularly limited, and for example, olefin resin, styrene resin, styrene acrylic resin, silicone resin, ester resin, fluorine-containing polymer resin, or the like is used. The resin for constituting the resin-dispersed carrier is not particularly limited, and known resins can be used. For example, styrene acrylic resin, polyester resin, fluorine resin, phenol resin, etc. can be used. it can.

  The method for producing the toner is not particularly limited. For example, a known pulverization method, a wet melt spheronization method prepared in a dispersion medium, suspension polymerization, dispersion polymerization, emulsion polymerization aggregation method and the like are known. And the like.

  In addition, an appropriate amount of inorganic fine particles such as silica and titania having an average particle diameter of about 10 to 300 nm and an abrasive of about 0.2 to 3 μm can be externally added to the toner particles as external additives.

The toner can be used as a magnetic or nonmagnetic one-component developer, but may be mixed with a carrier and used as a two-component developer.
In the case where the toner is used as a two-component developer, the carrier may be a conventionally known material such as a ferromagnetic metal such as iron, an alloy such as ferromagnetic metal and aluminum and lead, and a compound of ferromagnetic metal such as ferrite and magnetite. In particular, ferrite is preferable.

  As mentioned above, although embodiment of this invention was described concretely, embodiment of this invention is not limited to said example, A various change can be added.

  Hereinafter, specific examples of the present invention will be described, but the present invention is not limited thereto.

[Synthesis example 1 of (meth) acryl-modified phenoxy resin]
In a solution obtained by dissolving 10 parts by mass of a raw material phenoxy resin “PKHH” (manufactured by In Chem) in 80 parts by mass of dehydrated tetrahydrofuran (THF), (meth) acrylic acid halogen compound: 4.3 parts by mass of acrylic acid chloride and triethylamine After adding 4.8 mass parts and making it react at room temperature for 5 hours, the reaction liquid was dripped at the liquid mixture of 2500 mass parts of methanol / 2,500 mass parts of water, and the reaction material was deposited. Further, reprecipitation purification (good solvent; tetrahydrofuran, poor solvent; methanol) was followed by drying to obtain 10.1 parts by mass of (meth) acryl-modified phenoxy resin [1].
It was 85 mol% when the (meth) acryl modification rate of (meth) acryl modification phenoxy resin [1] was computed from the integral value of NMR.

[Synthesis examples 2 to 4 of (meth) acryl-modified phenoxy resin]
In Synthesis Example 1 of the (meth) acryl-modified phenoxy resin, except that the kind and amount of the raw material phenoxy resin and (meth) acrylic acid halogen compound were changed, the structure shown in Table 1 was similarly used (meth). Acrylic modified phenoxy resins [2] to [4] were obtained. Table 1 shows the (meth) acryl modification rate of the modified phenoxy resins [2] to [4].

[Synthesis Example 1x of Comparative Modified Phenoxy Resin]
4.0 parts by mass of phenylpropionic acid chloride and 2.4 parts by mass of triethylamine were added to a solution in which 10 parts by mass of the raw material phenoxy resin “PKHH” (manufactured by In Chem) was dissolved in 80 parts by mass of dehydrated tetrahydrofuran (THF). After reacting for 5 hours at room temperature, the reaction solution was dropped into a mixed solution of 2500 parts by mass of methanol / 2,500 parts by mass of water to precipitate the reaction product. Further, reprecipitation purification (good solvent; tetrahydrofuran, poor solvent; methanol) was followed by drying to obtain 9.8 parts by mass of a modified phenoxy resin [1x].
When the phenylpropionyl modification rate of the modified phenoxy resin [1x] was calculated from the integral value of NMR, it was 50 mol%.

[Synthesis Example 5 of (Meth) acrylic Modified Phenoxy Resin]
In a solution in which 10 parts by mass of the raw material phenoxy resin “PKHH” (manufactured by In Chem) was dissolved in 80 parts by mass of dehydrated tetrahydrofuran (THF), (meth) acrylic acid halogen compound: 4.0 parts by mass of methacrylic acid chloride, Si / F-containing compound: 1.5 parts by weight of tris (trimethylsiloxy) chlorosilane and 4.8 parts by weight of triethylamine were added and reacted at room temperature for 5 hours, and then the reaction solution was 2500 parts by weight of methanol / 2,500 parts by weight of water. The reaction product was precipitated by adding dropwise to the liquid mixture. Further, reprecipitation purification (good solvent; tetrahydrofuran, poor solvent; methanol) and drying were performed to obtain 10.2 parts by mass of (meth) acryl-modified phenoxy resin [5].
When the (meth) acryl modification rate of the (meth) acryl-modified phenoxy resin [5] is calculated from the integral value of NMR, it is 80 mol%, and the modification rate due to the Si / F-containing group is calculated from the integral value of NMR. 8 mol%.

[Synthesis Examples 6 to 24 of (Meth) acrylic Modified Phenoxy Resin]
In Synthesis Example 5 of the (meth) acryl-modified phenoxy resin, except that the type and amount of the raw material phenoxy resin, the (meth) acrylic acid halogen compound, and the compound supplying the Si / F-containing group were changed, (Meth) acryl-modified phenoxy resins [6] to [24] having the constitution shown in Table 1 were obtained. Table 1 shows the (meth) acryl modification rate and the modification rate due to the Si / F-containing groups of the modified phenoxy resins [6] to [24].

[Synthesis Example 3x of Modified Phenoxy Resin for Comparison]
In a solution obtained by dissolving 10 parts by mass of a raw material phenoxy resin “PKHH” (manufactured by In Chem) in 80 parts by mass of dehydrated tetrahydrofuran (THF), 4.0 parts by mass of phenylpropionic chloride and 1. tris (trimethylsiloxy) chlorosilane. After 5 parts by mass and 2.4 parts by mass of triethylamine were added and reacted at room temperature for 5 hours, the reaction solution was dropped into a mixed solution of 2500 parts by mass of methanol / 2,500 parts by mass of water to precipitate the reaction product. Further, reprecipitation purification (good solvent; tetrahydrofuran, poor solvent; methanol) and drying were performed to obtain 10.0 parts by mass of a modified phenoxy resin [3x].
When the phenylpropionyl modification rate of the modified phenoxy resin [3x] was calculated from the integral value of NMR, it was 42 mol%, and the modification rate due to the Si / F-containing group was calculated from the integral value of NMR, and was 11 mol%. It was.

[Example 1: Production of photoconductor 1]
(1) Formation of intermediate layer-Polyamide resin "CM8000 (manufactured by Toray Industries, Inc.)" 10 parts by mass-Titanium oxide (number average primary particle size 35 nm, primary surface treatment; silica / alumina treatment, secondary surface treatment; methyl hydrogen poly Siloxane treatment) A coating solution for forming an intermediate layer was prepared by dispersing a composition comprising 30 parts by mass, 90 parts by mass of methanol, and 5 parts by mass of ethanol using a circulation type wet disperser.
This intermediate layer forming coating solution was applied to the outer peripheral surface of a drum-shaped aluminum support by a dip coating method and dried to form an intermediate layer having a dry film thickness of 1.8 μm on the conductive support.

(2) Formation of charge generation layer (2-1) Synthesis of amorphous titanyl phthalocyanine 29.2 g of 1,3-diiminoisoindoline was dispersed in 200 ml of orthodichlorobenzene (ODB), and titanium tetra-n-butoxide 20. 4g was added and it heated at 150-160 degreeC for 5 hours in nitrogen atmosphere. After standing to cool, the precipitated crystals were filtered, washed with chloroform, washed with 2% aqueous hydrochloric acid, washed with water, washed with methanol in order, and dried to obtain 26.2 g (yield 91%) of crude titanyl phthalocyanine. Obtained.
Next, this crude titanyl phthalocyanine is added to 250 ml of concentrated sulfuric acid, dissolved by stirring at 5 ° C. or lower for 1 hour, poured into 5 L of water at 20 ° C., and the precipitated crystals are filtered and washed thoroughly with water. 225 g of wet paste product was obtained, frozen in a freezer, thawed, filtered and dried to obtain 24.8 g of amorphous titanyl phthalocyanine (yield 86%).

(2-2) Synthesis of Charge Generating Material [CG-1] 10.0 g of amorphous titanyl phthalocyanine [1] and 0.94 g of (2R, 3R) -2,3-butanediol (equivalent ratio to amorphous titanyl phthalocyanine = 0.6) was mixed in 200 ml of orthodichlorobenzene (ODB), and the mixture was heated and stirred at a reaction temperature of 60 to 70 ° C. for 6.0 hours. After standing overnight, methanol was added to the reaction solution, and the resulting crystals were filtered. The filtered crystals were washed with methanol to obtain 10.3 g of a charge generating material [CG-1].
When the X-ray diffraction spectrum of this charge generation material [CG-1] was measured, clear peaks were observed at 8.3 °, 24.7 °, 25.1 ° and 26.5 °. When the mass spectrum was measured, peaks were observed at 576 and 648, and when the IR spectrum was measured, absorption of Ti = O appeared in the vicinity of 970 cm ⁻¹ and O—Ti—O in the vicinity of 630 cm ^−1. Both absorptions appeared. Further, when thermal analysis (TG) was performed, there was a mass loss of about 7% at 390 to 410 ° C. From the above, it was estimated that the charge generation material [CG-1] was a mixed crystal of titanyl phthalocyanine and (2R, 3R) -2,3-butanediol 1: 1 adduct and non-added titanyl phthalocyanine. .

(2-3) Formation of Charge Generation Layer / Charge Generation Substance [CG-1] 24 parts by mass / polyvinyl butyral resin “ESREC BL-1 (manufactured by Sekisui Chemical Co.)” 12 parts by mass / 3-methyl-2-butanone / Cyclohexanone = 4/1 (V / V) A charge generation layer composition consisting of 400 parts by mass was mixed and added to a circulating ultrasonic homogenizer “RUS-600TCVP (manufactured by Nippon Seiki Seisakusho, 19.5 kHz, 600 W)”. Then, a coating solution for forming a charge generation layer was prepared by dispersing at a circulating flow rate of 40 L / H for 0.5 hour.
This charge generation layer forming coating solution was applied onto the intermediate layer by a dip coating method to form a charge generation layer having a dry film thickness of 0.3 μm.

(3) Formation of Charge Transport Layer Next, the following components were mixed and dissolved to prepare a charge transport layer forming coating solution.
-600 parts by mass of charge transporting material represented by the following formula (CTM-1)-1000 parts by mass of polycarbonate resin "Z300 (manufactured by Mitsubishi Gas Chemical)"-Antioxidant "Irganox 1010" (manufactured by Ciba Specialty Chemicals)
40 parts by mass This charge transport layer forming coating solution was applied onto the charge generation layer by a dip coating method and dried at 120 ° C. for 70 minutes to form a charge transport layer having a dry film thickness of 24 μm.

(4) Formation of surface layer Next, the following components were mixed and dissolved to prepare a surface layer forming coating solution.
-(Meth) acryl-modified phenoxy resin [1] 100 parts by mass-Charge transport material represented by the following formula (CTM-2) 30 parts by mass-Polymerization initiator "Irgacure 819" (manufactured by BASF Japan) 10 parts by mass -500 parts by weight of methyl ethyl ketone After coating this surface layer forming coating solution on the charge transport layer using a circular slide hopper coating machine, it was irradiated with ultraviolet rays for 1 minute using a metal halide lamp, and the dry film thickness was 3.0 μm. Thus, a photoreceptor [1] was produced.

[Examples 2 to 24: Photoconductor Production Examples 2 to 24]
Photoreceptor [2] to [2] in the same manner as in Preparation Example 1 of the photoreceptor except that the composition according to the formulation of Table 2 was used instead of 100 parts by mass of (meth) acryl-modified phenoxy resin [1]. 24] were obtained respectively.
However, SnO ₂ and CuAlO ₂ in Table 2 are those which are surface treated with a silane coupling agent having a (meth) acryloyl groups.

[Comparative Example 1: Photoconductor Preparation Example 1x]
A photoconductor [1x] for comparison was obtained in the same manner as in photoconductor production example 1 except that the surface layer was formed as follows.
First, a coating solution for forming a surface layer was prepared by mixing and dissolving the following components.
-Modified phenoxy resin [1x] 100 parts by mass-Charge transporting substance represented by the above formula (CTM-2) 30 parts by mass-Diphenylmethane diisocyanate 30 parts by weight-Methyl ethyl ketone 500 parts by weight The layer was coated on a layer using a circular slide hopper coater and dried at 120 ° C. for 70 minutes to form a surface layer having a dry film thickness of 3.0 μm. Thus, a comparative photoreceptor [1x] was produced.

[Comparative Example 2: Photoconductor Preparation Example 2x]
A photoconductor [2x] was obtained in the same manner as in photoconductor production example 1 except that the composition according to the formulation in Table 2 was used instead of 100 parts by mass of (meth) acryl-modified phenoxy resin [1]. It was.

[Comparative Example 3: Photoconductor Preparation Example 3x]
A photoconductor [3x] was obtained in the same manner as in Production Example 1x of Photoconductor except that the modified phenoxy resin [3x] was used instead of the modified phenoxy resin [1x].

<Evaluation Experiment 1>
Using “bizhub PRO C6501” (manufactured by Konica Minolta) as an evaluation machine, the photoconductors [1] to [4] and the photoconductors [1x] to [2x] for comparison are mounted on the evaluation machine. Evaluation was performed.
First, an endurance test was performed in which a character image with an image ratio of 6% was printed continuously at 500,000 sheets each in A4 horizontal feed in a normal temperature and high humidity environment (temperature 23 ° C., humidity 80% RH). The wear resistance, scratch resistance, potential stability, and image blur were evaluated. The results are shown in Table 3.

(1) Evaluation of wear resistance Before and after the endurance test, the total thickness of the intermediate layer, charge generation layer, charge transport layer and surface layer of the photoreceptor is measured, and the amount of wear is calculated. The wear resistance was evaluated according to The film thickness of the surface layer can be any 10 in a portion where the film thickness is uniform except for the film thickness variation portion (the front end portion and the rear end portion where the surface layer forming coating solution is applied). It measured about the location and made it the average value. The film thickness was measured using an eddy current type film thickness measuring device “EDDY560C” (manufactured by HELMUT FISCHER GMBTE CO).
-Evaluation criteria-
A: Amount of wear is 0.7 μm or less (pass)
B: The amount of wear is larger than 0.7 μm and 1.5 μm or less (pass)
C: The amount of wear is greater than 1.5 μm (failed)

(2) Evaluation of scratch resistance After the durability test, a halftone image was printed on the entire surface of A3 size paper, the surface of the photoreceptor and the halftone image were visually observed, and evaluated according to the following evaluation criteria.
-Evaluation criteria-
A: Conspicuous scratches are not confirmed on the surface of the photoreceptor, and no image defects are confirmed even in the halftone image (pass).
B: Although slight scratches are confirmed on the surface of the photoreceptor, no image defect corresponding to the scratches on the photoreceptor is confirmed in the halftone image (pass).
C: The occurrence of scratches is clearly confirmed on the surface of the photoreceptor, and the occurrence of image defects corresponding to the scratches on the photoreceptor is also confirmed in the halftone image (failure).

(3) Evaluation of potential stability (3-1) Evaluation of image density After the endurance test, a black solid image was printed on the entire surface of A3 size paper, and the image density of the black solid image was determined as “RD-918” ( Macbeth Co., Ltd.) was used to measure the relative reflection density of the paper, which was measured in advance, and evaluated according to the following evaluation criteria. Note that when a large number of sheets are printed and the residual potential increases, the image density decreases.
-Evaluation criteria-
A: Image density is 1.2 or more (pass)
B: Image density is 1.0 or more and less than 1.2 (pass)
C: Image density is less than 1.0 (failed)

(3-2) Evaluation of Image Fog After printing the above-described black solid image, a white solid image is printed on the entire surface of A3 size paper, and the image density of the white solid image is “RD-918” (manufactured by Macbeth). ) Was measured as a relative reflection density where the reflection density of the paper measured in advance was set to “0” and evaluated according to the following evaluation criteria. Note that image fogging occurs when the charging potential decreases greatly.
-Evaluation criteria-
A: Image density is less than 0.005 (pass)
B: Image density is 0.005 or more and less than 0.01 (pass)
C: Image density is 0.01 or more (failed)

(4) Evaluation of image blur Immediately after the endurance test, the main power supply of the actual machine was stopped, and after 12 hours the power was turned on and printing was possible. Immediately after that, a halftone image (Macbeth densitometer on the entire surface of A3 size paper) And a 6 dot lattice image was printed on the entire surface of A3 size paper, and the printed state was visually observed and evaluated according to the following evaluation criteria.
-Evaluation criteria-
A: Generation of image blur is not confirmed in both the halftone image and the 6 dot lattice image (pass)
B: Only a halftone image has a thin strip-shaped density reduction portion extending in the longitudinal direction of the photoreceptor (accepted)
C: Generation of defects due to image blur or thinning of line width is confirmed in 6 dot lattice image (failed)

<Evaluation Experiment 2>
In the evaluation experiment 1, the photoconductors [5] to [24] and the photoconductor for comparison [3x] were used as photoconductors, respectively, and durability tests were performed in a high temperature and high humidity environment (temperature 30 ° C., humidity 80% RH). In the same manner, the abrasion resistance, scratch resistance, potential stability, and image blur of the photoreceptor were evaluated. The results are shown in Table 3.

1Y, 1M, 1C, 1Bk Photoconductors 2Y, 2M, 2C, 2Bk Charging means 3Y, 3M, 3C, 3Bk Exposure means 4Y, 4M, 4C, 4Bk Developing means 5Y, 5M, 5C, 5Bk Primary transfer roller 5b Secondary transfer Rollers 6Y, 6M, 6C, 6Bk, 6b Cleaning means 7 Intermediate transfer body unit 8 Housing 10Y, 10M, 10C, 10Bk Image forming unit 20 Paper feed cassette 21 Paper feed means 22A, 22B, 22C, 22D Intermediate roller 23 Registration roller 24 Fixing means 25 Paper discharge roller 26 Paper discharge tray 70 Intermediate transfer bodies 71, 72, 73, 74 Rollers 82L, 82R Support rail A Main body SC Document image reading device P Transfer material

Claims (2)

In an electrophotographic photoreceptor in which a photosensitive layer and a surface layer are laminated in this order on a conductive support,
The electrophotographic photoreceptor, wherein the surface layer contains a cured product obtained by polymerizing a (meth) acryl-modified phenoxy resin containing a repeating unit represented by the following general formula (A).

[Wherein, R ¹ and R ² each independently represents a hydrogen atom, a halogen atom, an alkyl group or an aryl group, and R ³ represents a hydrogen atom or a methyl group. A represents a single bond, —O—, —CR ⁴ R ⁵ — or —SO ₂ —, and R ⁴ and R ⁵ each independently represents a hydrogen atom, an alkyl group or an aryl group. R ⁴ and R ⁵ may combine to form a ring. ] The electrophotographic photoreceptor according to claim 1, wherein the (meth) acryl-modified phenoxy resin further contains a repeating unit represented by the following general formula (B).

[Wherein, R ¹ and R ² each independently represents a hydrogen atom, a halogen atom, an alkyl group or an aryl group. A represents a single bond, —O—, —CR ⁴ R ⁵ — or —SO ₂ —, and R ⁴ and R ⁵ each independently represents a hydrogen atom, an alkyl group or an aryl group. R ⁴ and R ⁵ may combine to form a ring. X represents an organic group containing a silicon atom and / or a fluorine atom. ]

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