阅读说明：本技术 电子照相感光构件及其制造方法、处理盒和电子照相设备 (Electrophotographic photosensitive member, process cartridge, electrophotographic apparatus, and method of manufacturing electrophotographic photosensitive member ) 是由 渡部博之 西田孟 石塚由香 奥田笃 下泽秀春 中村延博 三浦大祐 于 2019-05-31 设计创作，主要内容包括：本发明涉及电子照相感光构件及其制造方法、处理盒和电子照相设备。提供一种在长期使用中不引起膜剥落的电子照相感光构件。一种电子照相感光构件,其依次具有：支承体；层叠型感光层；和保护层,其中保护层是单层,所述保护层包括：至少两种特定结构,两种特定结构以20％且240％以下的质量比包含在保护层中,基于保护层的末端烯烃(CH<Sub>2</Sub>＝)的面内弯曲振动的峰面积和基于丙烯酰氧基的C＝O的伸缩振动的峰面积具有固定的关系,所述峰面积是在内部反射元件为Ge且入射角为45°的条件下,通过全反射傅里叶变换红外光谱求得的。(an electrophotographic photosensitive member having a support, a laminated photosensitive layer, and a protective layer, wherein the protective layer is a single layer, the protective layer includes at least two specific structures contained in the protective layer at a mass ratio of 20% to 240% or less, and a peak area based on in-plane bending vibration of a terminal olefin (CH 2 ═) of the protective layer and a peak area based on stretching vibration of acryloyloxy C ═ O have a fixed relationship, the peak areas being obtained by total reflection Fourier transform infrared spectroscopy under conditions that an internal reflection element is Ge and an incident angle is 45 degrees.)

1. An electrophotographic photosensitive member having, in order: a support; a laminated photosensitive layer; and a protective layer, which is provided on the substrate,

Characterized in that the protective layer is a single layer, the protective layer comprising: a structure represented by formula I; and a structure represented by formula II, the structure represented by formula I being contained in the protective layer at a mass ratio of 20% or more and 240% or less based on the structure represented by formula II, and

a value, which is obtained by total reflection Fourier transform infrared spectroscopy under the conditions that the internal reflection element is Ge and the incident angle is 45 DEG and is represented by the following formula (1), satisfies the following formulae (2) to (4),

Wherein, in formula I and formula II, R is each independently a hydrogen atom or a methyl group, n is each independently an integer of 2 to 5,

(1)A＝S1/S2

Wherein, in formula 1, S1 is a peak area based on in-plane bending vibration of CH ₂ ═ of the terminal olefin, S2 is a peak area based on stretching vibration of C ═ O of the acryloxy group,

(2)0.003≤A1≤0.023

(3)0.005≤A2≤0.030

(4)0.2≤A1/A2≤0.97

Wherein, in the formulae (2) to (4), a1 is an a value determined from the surface side of the electrophotographic photosensitive member in the protective layer, and a2 is an a value determined from the interface side with the laminated photosensitive layer in the protective layer.

2. The electrophotographic photosensitive member according to claim 1, wherein the stacked photosensitive layer is a photosensitive layer including a charge generating layer and a charge transporting layer, a sum of average film thicknesses of the protective layer and the charge transporting layer is 10 μm or more and 17 μm or less, and a ratio of the average film thickness of the protective layer to the sum of average film thicknesses of the protective layer and the charge transporting layer is 10% or more and 30% or less.

3. The electrophotographic photosensitive member according to claim 1, wherein an A value of the protective layer satisfies formulae (5) to (7),

(5)0.003≤A1≤0.020

(6)0.008≤A2≤0.024

(7)0.3≤A1/A2≤0.85。

4. A method of manufacturing an electrophotographic photosensitive member according to claim 1, characterized by comprising:

Preparing a coating liquid for the protective layer; coating the coating liquid to form a coating film; irradiating the coating film with an electron beam; and curing the coating film by heating,

In the case of irradiation with an electron beam,

An acceleration voltage of an electron beam is 40kV or more and 70kV or less, and a distance between a surface of the coating film and an irradiation window foil of an electron beam irradiation apparatus is 10mm or more and 40mm or less, so that an electron beam absorbed dose of the surface of the coating film is 5kGy or more and 45kGy or less,

In the case of curing by heating, the curing agent,

The final temperature of the heating temperature is 100 ℃ or more and 150 ℃ or less, and

The method comprises performing electron beam irradiation and heat curing at an oxygen concentration of 300ppm or less.

5. the method for producing an electrophotographic photosensitive member according to claim 4, wherein at the time of heat curing, heating is performed for a temperature rise time of 5 seconds or more and 60 seconds or less.

6. A process cartridge characterized in that it integrally supports the electrophotographic photosensitive member according to claim 1 and at least one unit selected from the group consisting of a charging unit, a developing unit and a cleaning unit, and the process cartridge is detachably mountable to a main body of an electrophotographic apparatus.

7. An electrophotographic image forming apparatus, characterized by comprising: the electrophotographic photosensitive member according to claim 1; and at least one unit selected from the group consisting of a charging unit, an exposing unit, a developing unit, and a transferring unit.

Technical Field

The present invention relates to an electrophotographic photosensitive member and a method of manufacturing the same, and a process cartridge and an electrophotographic image forming apparatus having the electrophotographic photosensitive member.

Background

Heretofore, electrophotographic photosensitive members arranged in electrophotographic image forming apparatuses (hereinafter also referred to as "electrophotographic apparatuses") have been widely studied to improve sensitivity and abrasion resistance. As an example thereof, sensitivity and abrasion resistance have been improved by using a charge transporting substance having a radical polymerizable group in an upper layer of a charge transporting layer of an electrophotographic photosensitive member as a protective layer and curing it.

In the case of the laminated photosensitive member, when the difference between the elastic deformation rates of the upper and lower layers is large, interfacial strain (distorted), film peeling easily occurs. Particularly, the crosslinked cured film is liable to peel off due to few polar functional groups, high elastic deformation rate, and the like.

In order to solve this problem, in japanese patent application laid-open No. 2010-66672, the curability of the interface of the crosslinked cured film is adjusted to improve the durability.

In japanese patent application laid-open No. 2017-161718, the contact angle of the lower layer and the elastic deformation rate of the upper layer are adjusted, thereby suppressing the film peeling.

disclosure of Invention

The above object is achieved by the following invention. That is, the electrophotographic photosensitive member according to the present invention is an electrophotographic photosensitive member having a support, a laminated photosensitive layer, and a protective layer in this order, wherein the protective layer is a single layer, the protective layer includes a structure represented by formula I and a structure represented by formula II, the structure represented by formula I is contained in the protective layer at a mass ratio of 20% or more and 240% or less based on the structure represented by formula II, a value a, which is obtained by total reflection fourier transform infrared spectroscopy under the condition that an internal reflection element is Ge and an incident angle is 45 °, and which is represented by the following formula (1) satisfies the following formulae (2) to (4),

Wherein, in formula I and formula II, R is each independently a hydrogen atom or a methyl group, n is each independently an integer of 2 to 5,

(1)A＝S1/S2

Wherein, in formula 1, S1 is a peak area based on in-plane bending vibration of a terminal olefin (CH ₂ ═ O), S2 is a peak area based on C ═ O stretching vibration of an acryloyloxy group,

(2)0.003≤A1≤0.023

(3)0.005≤A2≤0.030

(4)0.2≤A1/A2≤0.97

In the formulae (2) to (4), a1 is an a value obtained from the surface side of the protective layer, and a2 is an a value obtained from the interface side with the laminated photosensitive layer in the protective layer.

Another aspect of the present invention is a method of manufacturing an electrophotographic photosensitive member, having:

Preparing a coating liquid for the protective layer; coating the coating liquid to form a coating film; irradiating the coating film with an electron beam; the coating film is cured by heating and, after the curing,

In the case of irradiation with an electron beam,

An acceleration voltage of the electron beam is 40kV or more and 70kV or less, and a distance between a surface of the coating film and an irradiation window foil of an electron beam irradiation apparatus is 10mm or more and 40mm or less so that an electron beam absorbed dose on the surface of the coating film is 5kGy or more and 45kGy or less,

In the case of curing by heating, the curing agent,

The final temperature of the heating temperature is 100 ℃ or more and 150 ℃ or less, and the method includes performing electron beam irradiation and heat curing at an oxygen concentration of 300ppm or less.

Another aspect of the present invention is a process cartridge, wherein the process cartridge integrally supports an electrophotographic photosensitive member and at least one unit selected from the group consisting of a charging unit, a developing unit, and a cleaning unit, and is detachably mountable to a main body of an electrophotographic apparatus.

Another aspect of the present invention is an electrophotographic image forming apparatus having: an electrophotographic photosensitive member; and at least one unit selected from the group consisting of a charging unit, an exposing unit, a developing unit, and a transferring unit.

Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings.

Drawings

Fig. 1 is a schematic view of an electrophotographic image forming apparatus having a process cartridge including an electrophotographic photosensitive member according to one embodiment of the present invention.

Detailed Description

Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

As a result of the studies by the present inventors, it has been found that the constitution disclosed in japanese patent application laid-open No. 2010-66672 or japanese patent application laid-open No. 2017-161718 may not be sufficient to suppress film peeling between the charge transport layer and the protective layer.

An object of the present invention is to provide an electrophotographic photosensitive member which does not cause film peeling in long-term use and a method of efficiently manufacturing the electrophotographic photosensitive member.

The present invention will be described in detail by the following preferred embodiments.

Since the protective layer of the photosensitive member and the charge transport layer included in the stacked photosensitive layer have a large difference in elastic modulus, the interface between the protective layer and the charge transport layer is strained by external stress, and film peeling is likely to occur. To solve this problem, there is a method of lowering the elastic modulus of the protective layer. However, when the elastic modulus is excessively reduced, the releasability between the protective layer and another member such as a cleaning blade is reduced. Therefore, the protective layer is strained, and film peeling occurs. Thus, in the present invention, forming the cured product in which the structure represented by formula I is contained in the protective layer at a mass ratio of 20% or more and 240% or less based on the structure represented by formula II as a single-layer protective layer in which the a value represented by formula (1) satisfies formulas (2) to (4), reduces the difference in elastic modulus at the interface between the protective layer and the charge transport layer while maintaining satisfactory releasability between the protective layer and another member, promotes enhancement of the interaction at the interface between the protective layer and the charge transport layer, and suppresses film peeling. This mechanism will be described.

In formula I and formula II, each R is independently a hydrogen atom or a methyl group, and each n is independently an integer of 2 to 5.

It is considered that when the composition containing the structure represented by formula I and the structure represented by formula II is cured, curing on the surface side of the protective layer proceeds more easily than curing on the interface side with the charge transport layer. This is because the structure represented by formula I has less steric hindrance than the structure represented by formula II, and the structure represented by formula I has a characteristic of being easily moved to the protective layer surface side in a wet film and being easily cured. Meanwhile, since the structure represented by formula II having a large steric hindrance is accumulated on the interface side with the charge transport layer, curing is difficult to proceed. This lowers the elastic modulus only on the interface side of the protective layer and the charge transport layer, and promotes the interaction with the charge transport layer by the unreacted acryloyloxy group (hereinafter also referred to as "residual functional group"), and improves the adhesion between the protective layer and the charge transport layer. The protective layer including the structure represented by formula I and the structure represented by formula II is more resistant to film peeling than the protective layer including only the structure represented by formula II. Although the reason is not clear, it is presumed that a stronger interaction occurs because the remaining functional group having the structure represented by formula II is easily oriented in the direction perpendicular to the charge transport layer by the influence of the structure represented by formula I.

₂The adhesion between the protective layer 72 and the protective layer 72 is more than the adhesion between the protective layer 72 and the protective layer 72 surface, and the adhesion between the protective layer 72 and the protective layer 72 surface is more than the adhesion between the protective layer 72 surface, and the protective layer 72 surface is more than the adhesion between the protective layer 72 surface and the protective layer 72 surface, and the adhesion between the protective layer 72 surface is more than the adhesion between the protective layer 72 surface and the protective layer 72 surface, and the adhesion between the protective layer 72 surface and the protective layer surface is more than the adhesion between the protective layer 72 surface and the protective layer 72 surface, and the adhesion between the protective layer 72 surface is more than the adhesion between the protective layer 72 surface, and the protective layer 72 surface is more than the adhesion when the adhesion between the protective layer 72 surface is more than the adhesion between the protective layer 72 surface, and the protective layer 72 surface, the protective layer 72 surface is more than the adhesion, and the adhesion between the protective layer 72 surface, the protective layer 72 surface is more than the adhesion, the adhesion between the protective layer 72, and the protective layer 72, the adhesion between the protective layer 72 surface is more than the adhesion, and the adhesion, the adhesion between the protective layer is more than the adhesion between the protective layer 72, and the protective layer, and the adhesion, the adhesion between the protective layer, and the protective layer, the adhesion, the protective layer, the adhesion between the protective layer, and the adhesion between the protective layer, the adhesion between the protective layer, the adhesion, the protective layer, the adhesion, the protective layer, and the protective layer, when the protective layer, the adhesion, the protective layer, the adhesion, the protective layer, and the protective layer, the adhesion, the protective layer, and the adhesion, and the adhesion, the protective layer, the adhesion, and the adhesion, the protective layer, the adhesion, and the protective layer, and the protective layer, the adhesion, the.

When controlling the value of a1 and the value of a2, a method of laminating protective layers is considered. However, in this method, the interface between the first protective layer and the second protective layer is the starting point of film peeling. Therefore, the protective layer in the present invention needs to be a single layer.

A method for measuring the protective layer of the electrophotographic photosensitive member of the present invention using total reflection fourier transform infrared spectroscopy (hereinafter referred to as "ATR method") will be described below.

The ATR method is a method of measuring by adhering a sample to a crystal called an internal reflection element (hereinafter referred to as "IRE") having a higher refractive index than the sample, and causing infrared light to enter the crystal at an incident angle higher than the critical angle. This method is a method using total reflection caused by allowing slight infrared light to enter the sample side of the interface between the sample and the crystal.

In the ATR method, the depth of entry of infrared light into the sample side (detection depth) is determined by the refractive index of IRE and the incident angle of the optical path. The A value of the present invention was measured under the conditions that IRE was Ge (refractive index: 4.0) and the incident angle was 45 deg.. Thereby calculating the degree of polymerization in the vicinity of the surface.

In the measurement of the ATR method, it is important to reduce the noise level of the spectrometer, and for this purpose, it is necessary to use a high-sensitivity spectrometer, increase the number of scans, and the like.

As the infrared spectrometer used in the present invention, FT-IR having high frequency accuracy and photometric accuracy is used. The number of scans is more preferably 32 or more. When the number of scans is less than this value, the influence of noise is large, and accurate measurement may not be possible.

The shape of the electrophotographic photosensitive member when measured by the ATR method may be any shape as long as contact with IRE can be sufficiently maintained.

The following will describe formulae I-1 to I-3, which are preferred examples of the structures represented by the above formula I. Among them, the structures represented by the formula I-1 and the formula I-2 are more preferable.

The following will describe formulae II-1 to II-3, which are preferred examples of the structures represented by the above formula II. Among them, the structure represented by the formula II-1 is more preferable.

The effect of the present invention is more remarkable in an electrophotographic photosensitive member in which the sum of the average film thicknesses of the protective layer and the charge transport layer is 10 μm or more and 17 μm or less and the ratio of the average film thickness of the protective layer to the sum of the average film thicknesses of the protective layer and the charge transport layer is 10% or more and 30% or less. As a result of the studies by the present inventors, it has been found that, in the case where the sum of the average film thicknesses of the protective layer and the charge transport layer is 10 μm or more and 17 μm or less, when the ratio of the average film thickness of the protective layer to the sum of the average film thicknesses of the protective layer and the charge transport layer is more than 30%, the volume change of the protective layer caused by external stress increases, and therefore the strain on the interface increases, and film peeling easily occurs. It has been found that film peeling also easily occurs when the ratio of the average film thickness of the protective layer to the sum of the average film thicknesses of the protective layer and the charge transport layer is less than 10%. This is considered because the interface may be easily deformed by stress derived from the curvature of the cylindrical tube. The film thickness was measured at 8 points 135mm lower than the upper end of the cylinder in the circumferential direction, and the average film thickness was the average of the values thereof. Although any method may be used to measure the film thickness, a film thickness meter using, for example, an eddy current method may be used. An example of the film thickness meter using the eddy current method includes LH-200J manufactured by Kett electric laboratory. The average film thickness of the protective layer and the charge transport layer was calculated as the difference between before and after film formation of each layer.

In the method for producing an electrophotographic photosensitive member of the present invention, the production of the protective layer is preferably a method having the steps of: preparing a coating liquid for the protective layer; coating the coating liquid to form a coating film; irradiating the coating film with an electron beam; curing the coated film by heating, wherein, upon irradiation with an electron beam, an acceleration voltage of the electron beam is 40kV or more and 70kV or less, and a distance between a surface of the coated film and an irradiation window foil of an electron beam irradiation apparatus is 10mm or more and 40mm or less, so that an electron beam absorbed dose of the coated film surface is 5kGy or more and 45kGy or less, upon curing by heating, a final temperature of the heating temperature is 100 ℃ or more and 150 ℃ or less, and the method comprises performing electron beam irradiation and heat curing at an oxygen concentration of 300ppm or less

In the production of the protective layer, electron beam curing in which the curing depth can be controlled by an acceleration voltage and an irradiation distance is preferable to control the curing of the coating film in the depth direction of the film. The atmosphere for electron beam irradiation and heat curing is preferably 300ppm or less in oxygen concentration, and particularly preferably 100ppm or less in oxygen concentration. When the oxygen concentration is more than 300ppm, curability may deteriorate.

When the acceleration voltage of the electron beam is less than 40kV upon irradiation with the electron beam, the electron beam penetrates into the protective layer shallowly, the curing of the protective layer is insufficient, and therefore the abrasion resistance of the protective layer deteriorates. When the acceleration voltage of the electron beam is more than 70kV, the electron beam penetrates too deeply into the protective layer, the curing on the interface side between the protective layer and the charge transport layer is promoted, the interaction between the protective layer and the charge transport layer due to the residual functional group is weakened, and film peeling easily occurs. The acceleration voltage of the electron beam is more preferably 40kV or more and 60kV or less.

Further, when the electron beam absorption dose of the surface of the coating film is less than 5kGy, curing of the coating film does not proceed. When the absorbed dose is more than 45kGy, the photosensitive member characteristics deteriorate. The electron beam absorption dose on the surface of the coating film is more preferably in the range of 10kGy to 35 kGy.

The electron beam absorbed dose on the surface of the coating film can be measured by a general film gauge such as Radiachromic Reader and Radiachromic Dosimeter (10 μm) manufactured by FarWest Technology, inc.

In the present invention, the electron beam absorbed dose of the surface of the coating film is defined as an absorbed dose measured when a film of a Radiachromic Dosimeter (10 μm) attached to the surface of the electrophotographic photosensitive member before coating with the coating liquid for the protective layer is irradiated with an electron beam.

In addition, when the distance (irradiation distance) between the surface of the coating film and the irradiation window foil of the electron beam irradiation apparatus is less than 10mm, the electron beam penetrates deeply into the protective layer, curing on the interface side proceeds too much, the residual functional groups decrease, and thus the adhesiveness with the charge transport layer deteriorates. When the irradiation distance is more than 40mm, the electron beam penetrates into the protective layer shallowly, curability of the protective layer is insufficient, and thus abrasion resistance of the protective layer deteriorates. Here, the distance between the surface of the coating film and the irradiation window foil of the electron beam irradiation apparatus means the shortest distance between the surface of the coating film and the irradiation window foil of the electron beam irradiation apparatus. In the electron beam irradiation apparatus, since the electron beam starts to be denatured (inactivated) after passing through the irradiation window foil, the distance between the surface of the coating film and the irradiation source is not specified in the present invention, but the distance between the surface of the coating film and the irradiation window foil is specified.

In addition, in the production of the electrophotographic photosensitive member of the present invention, after the coating film is irradiated with an electron beam, the coating film is cured by heating to form the coating film as a protective layer. In the case of curing by heating, when the final temperature of the heating temperature is lower than 100 ℃, curing cannot be sufficiently performed. When the final temperature of the heating temperature is higher than 150 ℃, the coating film is roughened. Therefore, the final temperature of the heating temperature is preferably 100 ℃ or more and 150 ℃ or less, and more preferably 110 ℃ or more and 130 ℃ or less.

The heat curing is performed by raising the temperature from the initial temperature to the final temperature, and the temperature rise time is preferably 5 seconds or more and 60 seconds or less. At this time, the initial temperature of the heat curing may be room temperature, or may be the temperature of the coating film after the electron beam irradiation, and more preferably the temperature of the coating film after the electron beam irradiation. When the temperature rise time is less than 5 seconds, the protective layer is slightly deformed at the time of curing because the temperature rise is too fast. When the temperature rise time exceeds 60 seconds, the charge transport layer is slightly deformed, which has a harmful effect on the adhesion between the protective layer and the charge transport layer.

As the above mechanism, since the respective constitutions have a synergistic effect with each other, an electrophotographic photosensitive member capable of realizing the effect of the present invention can be manufactured.

[ electrophotographic photosensitive Member ]

an electrophotographic photosensitive member according to one aspect of the present invention has a support, a laminated photosensitive layer, and a protective layer.

Examples of the method for producing the electrophotographic photosensitive member of the present invention include a method of preparing a coating liquid for each layer described below, applying the coating liquid in a desired layer order, and drying the coating liquid. Examples of the method of coating the coating liquid at this time include dip coating, spray coating, inkjet coating, roll coating, die coating, blade coating, curtain coating, wire bar coating, and loop coating. Among these, dip coating is preferable from the viewpoint of efficiency and productivity. Now, the layers will be described.

The layers will be described below.

< support >

In the present invention, the electrophotographic photosensitive member has a support. In the present invention, the support is preferably a conductive support having conductivity. Examples of the shape of the support include a cylindrical shape, a belt shape, and a sheet shape. In particular, the support is preferably a cylindrical support. The surface of the support may be subjected to electrochemical treatment such as anodic oxidation, blasting, cutting, or the like.

As a material of the support, metal, resin, glass, or the like is preferable.

Examples of metals include aluminum, iron, nickel, copper, gold, stainless steel, and alloys thereof. The support is preferably made of aluminum.

The resin and the glass can be imparted with electrical conductivity by, for example, a treatment of mixing the resin and the glass with an electrically conductive material or covering the resin and the glass with an electrically conductive material.

< conductive layer >

In the present invention, a conductive layer may be provided on the support. By providing the conductive layer, scratches or irregularities on the surface of the support can be hidden, and reflection of light on the surface of the support can be controlled.

Preferably, the conductive layer contains conductive particles and a resin.

Examples of the material of the conductive particles include metal oxides, metals, and carbon black.

Examples of the metal oxide include zinc oxide, aluminum oxide, indium oxide, silicon oxide, zirconium oxide, tin oxide, titanium oxide, magnesium oxide, antimony oxide, and bismuth oxide. Examples of metals include aluminum, nickel, iron, nichrome, copper, zinc, and silver.

among these, as the conductive particles, metal oxides are preferably used, and particularly, titanium oxide, tin oxide, or zinc oxide is more preferably used.

when a metal oxide is used as the conductive particles, the surface of the metal oxide may be treated with a silane coupling agent or the like, or the metal oxide may be doped with an element such as phosphorus or aluminum, or an oxide thereof.

The conductive particles may have a layered configuration including core material particles and a covering layer covering the particles. Examples of the core material particles include titanium oxide, barium sulfate, and zinc oxide. Examples of the capping layer include metal oxides such as tin oxide.

when a metal oxide is used as the conductive particles, the volume average particle diameter is preferably 1nm or more and 500nm or less, more preferably 3nm or more and 400nm or less.

Examples of the resin include polyester resins, polycarbonate resins, polyvinyl acetal resins, acrylic resins, silicone resins, epoxy resins, melamine resins, polyurethane resins, phenol resins, and alkyd resins.

The conductive layer may further contain a masking agent such as silicone oil, resin particles, or titanium oxide.

the average film thickness of the conductive layer is preferably 1 μm or more and 50 μm or less, and particularly preferably 3 μm or more and 40 μm or less.

The conductive layer can be formed by preparing a coating liquid for the conductive layer, which contains the above-described material and a solvent, forming a coating film thereof, and drying the coating film. Examples of the solvent used for the coating liquid include alcohol-based solvents, sulfoxide-based solvents, ketone-based solvents, ether-based solvents, ester-based solvents, and aromatic hydrocarbon-based solvents. Examples of a method of dispersing the conductive particles in the coating liquid for the conductive layer include a method using a paint shaker, a sand mill, a ball mill, or a liquid impact type high-speed dispersing machine.

< undercoat layer >

In the present invention, an undercoat layer may be provided on the support or on the conductive layer. By providing the undercoat layer, the adhesion function between layers is enhanced, and a charge injection preventing function can be imparted.

Preferably, the primer layer comprises a resin. The undercoat layer may be formed into a cured film by polymerizing a composition containing a monomer having a polymerizable functional group.

examples of the resin include polyester resins, polycarbonate resins, polyvinyl acetal resins, acrylic resins, epoxy resins, melamine resins, polyurethane resins, phenol resins, polyvinyl phenol resins, alkyd resins, polyvinyl alcohol resins, polyethylene oxide resins, polypropylene oxide resins, polyamide acid resins, polyimide resins, polyamideimide resins, and cellulose resins.

Examples of the polymerizable functional group possessed by the monomer having a polymerizable functional group include an isocyanate group, a blocked isocyanate group, a methylol group, an alkylated methylol group, an epoxy group, a metal alkoxide group, a hydroxyl group, an amino group, a carboxyl group, a thiol group, a carboxylic anhydride group, and a carbon-carbon double bond group.

In order to improve electrical properties, the undercoat layer may further contain an electron transport material, a metal oxide, a metal, a conductive polymer, and the like. Among them, electron transporting materials and metal oxides are preferably used.

Examples of the electron transporting material include quinone compounds, imide compounds, benzimidazole compounds, cyclopentadienylidene compounds, fluorenone compounds, xanthone compounds, benzophenone compounds, cyanovinyl compounds, halogenated aryl compounds, silole compounds, and boron-containing compounds. An electron transport material having a polymerizable functional group is used as the electron transport material. The undercoat layer can be formed into a cured film by copolymerizing the electron-transporting material with a monomer having the polymerizable functional group.

Examples of the metal oxide include indium tin oxide, indium oxide, titanium oxide, zinc oxide, aluminum oxide, and silicon dioxide. Examples of the metal include gold, silver, and aluminum.

The primer layer may further comprise an additive.

The average film thickness of the undercoat layer is preferably 0.1 μm or more and 50 μm or less, more preferably 0.2 μm or more and 40 μm or less, and particularly preferably 0.3 μm or more and 30 μm or less.

The undercoat layer can be formed by preparing a coating liquid for undercoat layer, which contains the above-mentioned material and a solvent, forming a coating film thereof, and drying and/or curing the coating film. Examples of the solvent used for the coating liquid include alcohol-based solvents, ketone-based solvents, ether-based solvents, ester-based solvents, and aromatic hydrocarbon-based solvents.

< photosensitive layer >

The photosensitive layer of the electrophotographic photosensitive member is roughly classified into a laminated type photosensitive layer and a single layer type photosensitive layer. The electrophotographic photosensitive member of the present invention is a laminated photosensitive layer having a charge generating layer containing a charge generating substance and a charge transporting layer containing a charge transporting substance.

(1) Charge generation layer

preferably, the charge generation layer contains a charge generation substance and a resin.

Examples of the charge generating substance include azo pigments, perylene pigments, polycyclic quinone pigments, indigo pigments, and phthalocyanine pigments. Among them, azo pigments and phthalocyanine pigments are preferable. Among the phthalocyanine pigments, oxytitanium phthalocyanine pigments, chlorogallium phthalocyanine pigments and hydroxygallium phthalocyanine pigments are preferable.

The content of the charge generating substance in the charge generating layer is preferably 40 mass% or more and 85 mass% or less, and more preferably 60 mass% or more and 80 mass% or less, based on the total mass of the charge generating layer.

Examples of the resin include polyester resins, polycarbonate resins, polyvinyl acetal resins, polyvinyl butyral resins, acrylic resins, silicone resins, epoxy resins, melamine resins, polyurethane resins, phenol resins, polyvinyl alcohol resins, cellulose resins, polystyrene resins, polyvinyl acetate resins, and polyvinyl chloride resins. Among the resins, a polyvinyl butyral resin is more preferable.

The charge generation layer may further include additives such as an antioxidant and an ultraviolet absorber. Specific examples include hindered phenol compounds, hindered amine compounds, sulfur compounds, phosphorus compounds, and benzophenone compounds.

The average film thickness of the charge generation layer is preferably 0.1 μm or more and 1 μm or less, and more preferably 0.15 μm or more and 0.4 μm or less.

The charge generating layer can be formed by preparing a coating liquid for a charge generating layer, which contains the above-described material and a solvent, forming a coating film thereof, and drying the coating film. Examples of the solvent used for the coating liquid include alcohol-based solvents, sulfoxide-based solvents, ketone-based solvents, ether-based solvents, ester-based solvents, and aromatic hydrocarbon-based solvents.

(2) Charge transport layer

Preferably, the charge transport layer contains a charge transport substance and a resin.

Examples of the charge transporting substance include polycyclic aromatic compounds, heterocyclic compounds, hydrazone compounds, styryl compounds, enamine compounds, biphenylamine compounds, triarylamine compounds, and resins having groups derived from these substances. Among them, triarylamine compounds and biphenylamine compounds are preferable.

The content of the charge transporting substance in the charge transporting layer is preferably 25 mass% or more and 70 mass% or less, more preferably 30 mass% or more and 55 mass% or less, based on the total mass of the charge transporting layer.

Examples of the resin include polyester resins, polycarbonate resins, acrylic resins, and polystyrene resins. Among them, polycarbonate resins and polyester resins are preferable. As the polyester resin, a polyarylate resin is particularly preferable.

The content ratio (mass ratio) of the charge transporting substance to the resin is preferably 4:10 to 20:10, more preferably 5:10 to 12: 10.

the charge transport layer may further contain additives such as an antioxidant, an ultraviolet absorber, a plasticizer, a leveling agent, a slip property imparting agent, and an abrasion resistance improving agent. Specific examples include hindered phenol compounds, hindered amine compounds, sulfur compounds, phosphorus compounds, benzophenone compounds, siloxane-modified resins, silicone oils, fluororesin particles, polystyrene resin particles, polyethylene resin particles, silica particles, alumina particles, and boron nitride particles.

The average film thickness of the charge transport layer is preferably 5 μm or more and 30 μm or less, and more preferably 8 μm or more and 20 μm or less.

The charge transporting layer can be formed by preparing a coating liquid for a charge transporting layer, which contains the above-mentioned material and a solvent, forming a coating film thereof, and drying the coating film. Examples of the solvent used for the coating liquid include alcohol-based solvents, ketone-based solvents, ether-based solvents, ester-based solvents, and aromatic hydrocarbon-based solvents. Among these solvents, ether solvents and aromatic hydrocarbon solvents are preferable.

< protective layer >

In the electrophotographic photosensitive member of the present invention, a surface layer serving as a protective layer is provided on the laminated photosensitive layer.

The protective layer includes structures having charge transporting ability and represented by formula I and formula II, and may be formed into a cured film by polymerizing a composition including a monomer having a polymerizable functional group corresponding to the structure represented by formula I and the structure represented by formula II. Examples of the reaction when the monomer is polymerized include thermal polymerization, photopolymerization, and radiation polymerization.

Examples of the monomer having a polymerizable functional group corresponding to the structure represented by formula I and the structure represented by formula II include compounds represented by the following formulae A-1 to A-10 and formulae B-1 to B-6.

The protective layer may contain additives such as an antioxidant, an ultraviolet absorber, a plasticizer, a leveling agent, a sliding property imparting agent, and an abrasion resistance improving agent. Specific examples include hindered phenol compounds, hindered amine compounds, sulfur compounds, phosphorus compounds, benzophenone compounds, siloxane-modified resins, silicone oils, fluororesin particles, polystyrene resin particles, polyethylene resin particles, silica particles, alumina particles, and boron nitride particles.

The protective layer may further contain conductive particles and/or a charge transporting substance, and a resin.

Examples of the conductive particles include particles of metal oxides such as titanium oxide, zinc oxide, tin oxide, and indium oxide.

Examples of the charge transporting substance include polycyclic aromatic compounds, heterocyclic compounds, hydrazone compounds, styryl compounds, enamine compounds, biphenylamine compounds, triarylamine compounds, and resins having groups derived from these substances. Among them, triarylamine compounds and biphenylamine compounds are preferable.

Examples of the resin include polyester resins, acrylic resins, phenoxy resins, polycarbonate resins, polystyrene resins, phenol resins, melamine resins, and epoxy resins. In particular, polycarbonate resins, polyester resins and acrylic resins are preferable.

The total amount of the structure represented by formula I and the structure represented by formula II in the protective layer is preferably 50% or more, more preferably 70% or more, based on the total mass of the protective layer.

From the viewpoint of electrophotographic characteristics, the average film thickness of the protective layer is preferably 0.5 μm or more and 10 μm or less, and preferably 1 μm or more and 7 μm or less. In particular, the sum of the average film thicknesses of the protective layer and the charge transport layer is preferably 10 μm or more and 17 μm or less, and the ratio of the average film thickness of the protective layer to the sum of the average film thicknesses of the protective layer and the charge transport layer is preferably 10% or more and 30% or less.

A detailed manufacturing method of the protective layer in the electrophotographic photosensitive member of the present invention will be described below.

The protective layer can be formed by preparing a coating liquid for the protective layer containing the above-mentioned material and a solvent, forming a coating film of the coating liquid for the protective layer, and then drying and/or curing the coating film. Any solvent may be used as the solvent of the coating liquid for a protective layer as long as the solvent is a solvent that can dissolve or disperse the above-mentioned materials. However, examples of the solvent include alcohol-based solvents, ketone-based solvents, ether-based solvents, sulfoxide-based solvents, ester-based solvents, and aromatic hydrocarbon-based solvents.

The monomers having polymerizable functional groups corresponding to the structure represented by formula I and the structure represented by formula II in the coating liquid for a protective layer are polymerized and crosslinked (hereinafter also simply referred to as "polymerization") by a known polymerization method. Examples of the polymerization method include a method of thermal polymerization using heat, a method of photopolymerization using light such as visible light and ultraviolet rays, and a method of radiation polymerization using radiation such as electron beams and γ rays. The polymerization initiator may be incorporated into the coating liquid for a protective layer in any method, if necessary. Among them, a method of radiation polymerization reaction which does not particularly require a polymerization initiator, particularly a method of polymerization reaction using electron beams, is preferably used. This is because a protective layer having a three-dimensional matrix with very high purity can be formed by polymerizing monomers having polymerizable functional groups corresponding to the structure represented by formula I and the structure represented by formula II without using a polymerization initiator. The electrophotographic photosensitive member having such a protective layer exhibits satisfactory electrophotographic characteristics. In the radiation, damage to the electrophotographic photosensitive member by irradiation by polymerization of the electron beam is very small, and satisfactory electrophotographic characteristics can be exhibited.

Irradiation with an electron beam can be performed using an electron beam irradiation apparatus such as a scanning type, an electric curtain type, a wide beam type, a pulse type, or a laminar flow type. The acceleration voltage of the electron beam is preferably 40kV or more and 70kV or less. The electron beam absorption dose on the surface of the coating film is preferably in the range of 5kGy or more and 45kGy or less. Preferably, the distance between the surface of the coating film and the irradiation window foil of the electron beam irradiation device is 10mm or more and 40mm or less.

it is preferable to heat the coating film after polymerization of the monomer having the polymerizable functional group corresponding to the structure represented by formula I and the structure represented by formula II. When the heating temperature is too high, the material of the electrophotographic photosensitive member may deteriorate. Therefore, it is preferable to heat the irradiation object so that the temperature of the irradiation object becomes 150 ℃ or lower. Meanwhile, when the heating temperature is excessively low, polymerization of the monomer having the polymerizable functional group corresponding to the structure represented by formula I and the structure represented by formula II may not sufficiently proceed. Therefore, it is preferable to heat the coating film so that the temperature of the coating film becomes 100 ℃ or higher.

Further, it is preferable to heat the coating film for 5 seconds to 60 seconds while raising the temperature, and it is more preferable to raise the temperature from the coating film temperature after electron beam irradiation to the heating temperature in the heating time.

Although the atmosphere at the time of irradiating and heating the irradiation object with the electron beam may be any of an atmospheric atmosphere, an inert gas such as nitrogen or helium, and a vacuum, an inert gas or a vacuum is preferable from the viewpoint that deactivation of radicals by oxygen can be suppressed. The oxygen concentration of the atmosphere when the irradiation object is irradiated and heated with the electron beam is preferably 300ppm or less.

The average film thickness of the protective layer of the electrophotographic photosensitive member is preferably 10 μm or less, more preferably 7 μm or less, from the viewpoint of electrophotographic characteristics. Meanwhile, the average film thickness of the protective layer is preferably 0.5 μm or more, more preferably 1 μm or more, from the viewpoint of durability of the electrophotographic photosensitive member.

[ Process Cartridge and electrophotographic apparatus ]

The process cartridge of the present invention, which integrally supports the above-described electrophotographic photosensitive member and at least one unit selected from the group consisting of a charging unit, a developing unit, and a cleaning unit, is detachably mountable to a main body of an electrophotographic apparatus.

An electrophotographic apparatus of the present invention has the above-described electrophotographic photosensitive member, a charging unit, an exposing unit, a developing unit, and a transfer unit.

One embodiment of an exemplary configuration of an electrophotographic apparatus having a process cartridge including an electrophotographic photosensitive member is shown in fig. 1.

First, reference numerals in fig. 1 will be described.

Reference numeral 1 denotes an electrophotographic photosensitive member, reference numeral 2 denotes a shaft, reference numeral 3 denotes a charging unit, reference numeral 4 denotes exposure light, reference numeral 5 denotes a developing unit, reference numeral 6 denotes a transfer unit, reference numeral 7 denotes a transfer material, reference numeral 8 denotes a fixing unit, reference numeral 9 denotes a cleaning unit, and reference numeral 10 denotes pre-exposure light. Reference numeral 11 denotes a process cartridge, and reference numeral 12 denotes a guide unit.

The cylindrical electrophotographic photosensitive member 1 is rotationally driven around the shaft 2 in the direction of the arrow at a predetermined peripheral speed. The surface of the electrophotographic photosensitive member 1 is charged to a predetermined positive potential or negative potential by the charging unit 3. In fig. 1, although a roller charging method using a roller-type charging member is shown, a charging method such as a corona charging method, a proximity charging method, or an injection charging method may be used. The surface of the electrophotographic photosensitive member 1 is irradiated with exposure light 4 from an exposure unit (not shown), and an electrostatic latent image corresponding to the target image information is formed. The electrostatic latent image formed on the surface of the electrophotographic photosensitive member 1 is developed with the toner stored in the developing unit 5, and a toner image is formed on the surface of the electrophotographic photosensitive member 1. The toner image formed on the surface of the electrophotographic photosensitive member 1 is transferred onto a transfer material 7 by a transfer unit 6. The transfer material 7 on which the toner image is transferred is conveyed to a fixing unit 8, subjected to a fixing process of the toner image, and printed to the outside of the electrophotographic apparatus. The electrophotographic apparatus may have a cleaning unit 9 to remove deposits such as toner remaining on the surface of the electrophotographic photosensitive member 1 after transfer. A so-called cleaner-less system in which a cleaning unit is not separately provided but the above-described deposits are removed by a developing unit or the like may be used. The electrophotographic apparatus may have a charge removing system that subjects the surface of the electrophotographic photosensitive member 1 to charge removing processing by pre-exposure light 10 from a pre-exposure unit (not shown). In order to detach the process cartridge of the present invention from the main body of the electrophotographic apparatus, a guide unit 12 such as a guide rail may be provided.

The electrophotographic photosensitive member of the present invention can be used for laser beam printers, LED printers, copiers, facsimile machines, multifunction machines thereof, and the like.