JP2013029590A - Electrophotographic photoreceptor and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor with high sensitivity and high responsivity in a long wavelength region, free from deterioration of the electric characteristics even after repeated use and superior in wear resistance and cleaning feature.SOLUTION: The electrophotographic photoreceptor has a charge generation layer and a charge transport layer formed over a substrate; the charge transport layer contains a binder resin and a compound expressed by a general formula (1); the binder resin is a polycarbonate copolymer of a specific structure; the elastic power of the charge transport layer at an indentation depth from the charge transport layer surface of 1 μm using a Vickers quadrangular pyramid diamond indenter with set weight of 9.8 mN is 38-48%; and universal hardness is 180-200 N/m. R-Rmay be different from one another, and represent hydrogen atoms, an alkyl group of carbon number 1-6 which may include a substitutional group or an alkoxyl group of carbon number 1-6 which may include a substitutional group.

Description

  The present invention relates to an electrophotographic photosensitive member (hereinafter also referred to as “photosensitive member” or “image carrier”) and an image forming apparatus using the electrophotographic photosensitive member.

  In recent years, there has been a remarkable development of information processing system machines using electrophotography. In particular, an optical printer that converts information into a digital signal and records information by light is markedly improved in print quality and reliability. This digital recording technique is applied not only to printers but also to ordinary copying machines, and so-called digital copying machines have been developed. In addition, since a variety of information processing functions are added to a conventional copying machine equipped with this digital recording technology for analog copying, it is expected that its demand will increase further in the future. Further, along with the spread of personal computers and the improvement in performance, the progress of digital color printers for performing color output of images and documents is rapidly progressing.

  Regarding electrophotographic photoreceptors, which are the core of electrophotographic technology, organic photoreceptors using organic photoconductive materials can be designed in various ways because they are pollution-free, low cost, and have a high degree of freedom in material selection. Many have been proposed and put into practical use because of their many advantages. The photosensitive layer of such an organic photoreceptor has a layered structure in which a charge generation layer in which a charge generation agent is dispersed in a binder resin and a charge transport layer in which a charge transfer agent is dispersed in a binder resin are stacked. And a single layer structure in which both the charge transport agent and the charge transport agent are dispersed in a binder resin have been proposed. Among these, as a photosensitive layer, a function-separated type photoreceptor in which a charge transport layer is laminated on a charge generation layer is excellent in electrophotographic characteristics and durability, and is widely put into practical use.

  Recent electrophotographic image forming apparatuses such as digital copiers and printers have been reduced in size and speed, and the photoconductor characteristics have increased responsiveness corresponding to higher speed and longer life due to improved wear resistance. Both characteristics are required. Among these, it can be achieved by using a highly responsive charge transfer agent to satisfy high responsiveness, and by using a binder resin with high wear resistance to satisfy long life. .

  Therefore, various methods aiming at both high light response and high durability have been proposed in order to cope with high speed machines. However, even with these conventional techniques, sufficient high sensitivity, high durability, and high cleaning properties are not yet fully satisfied. In order to achieve high mobility, it is common to increase the ratio of the charge transport agent to the binder resin in the charge transport layer. However, if the ratio of the charge transport agent is increased, the wear resistance tends to deteriorate. Furthermore, even with high sensitivity using a charge generating agent, there are problems of matching with the charge transport layer and repetitive characteristics, which is not sufficient in practice.

  Among phthalocyanine pigments as charge generating agents, oxytitanium phthalocyanine is mentioned as one having high sensitivity in the long wavelength region. Several crystal types have been reported for this oxytitanium phthalocyanine. Among these, those showing a maximum diffraction peak at 27.2 ° are considered to have high sensitivity. However, when used in a high-speed process, the potential characteristics of the photoreceptor after repeated use deteriorate, and fog, black streaks, density unevenness, and the like occur in the obtained image. When used in a high-speed process, even if the sensitivity is high, if the photoresponsiveness is not sufficient, charges remain in the photosensitive layer, which may cause fogging, black streaks, and uneven density in the next electrophotographic process. Become. As a charge generation agent, it is necessary to have a high charge transport capability, and a combination of a charge generation agent and a charge transport agent is important.

  Therefore, an electrophotographic photosensitive member having high sensitivity in the long wavelength region, high responsiveness, and stable reproducibility of the electrophotographic characteristics, particularly the initial potential and the potential after repeated use, even after repeated use at high speed is desired. It has been. Even if a charge generating agent having high charge generation efficiency is used, sufficient sensitivity cannot be obtained if the compatibility with the charge transporting agent is poor, and it is also high in various usage environments from high temperature and high humidity to low temperature and low humidity. Quality image is not obtained. The compatibility between charge generating agents and charge transporting agents has been studied from various viewpoints, and it is possible to use a specific crystal type oxytitanium phthalocyanine and a styryl based charge transporting agent containing triarylamine in an electrophotographic photoreceptor. It has been studied from the past.

  Also, when the photoreceptor is used repeatedly, not only the deterioration of the photoelectric properties of the photoreceptor, but also the surface of the photoreceptor is worn by contact with paper, cleaning means, contact type charging means, etc. Black streaks, density unevenness and the like occur. Many binder resins have been studied in order to improve the abrasion resistance of the photoreceptor surface. For example, many polycarbonate resins have been proposed as binder resins used in combination with styryl-based charge transfer agents containing triarylamine (see Patent Documents 1 to 7).

  In addition to improving the cleaning property and wear resistance, in addition to the selection of the binder resin and the ratio of the charge transport agent to the binder resin, the elastic deformation rate and universal hardness in the charge transport layer of the photosensitive layer should be optimized. Is also considered important.

JP-A-4-37858 JP-A-4-37860 JP-A-5-257298 JP-A-5-257297 Japanese Patent Laid-Open No. 10-20527 JP 2005-331735 A JP 2010-128187 A

  An object of the present invention is to solve the conventional problems and achieve the following objects. That is, the present invention can cope with the process of reducing the diameter of the photoconductor and the peripheral speed with the miniaturization and speeding up of the copying machine and the printer apparatus, and has high sensitivity and high response in a long wavelength range, and is repeated. An object of the present invention is to provide an electrophotographic photosensitive member that does not deteriorate in electrical characteristics even when used, and has high wear resistance and cleaning properties, and an image forming apparatus using the electrophotographic photosensitive member.

  As a result of intensive studies by the present inventors in order to solve the above problems, the charge transport layer contains a specific charge transport agent and a specific polycarbonate copolymer as a binder resin, and the charge on the surface of the photoreceptor. It has been found that the conventional problems can be effectively solved by having a specific elastic power and universal hardness in the transport layer, and preferably including a specific crystal type oxytitanium phthalocyanine in the charge generation layer.

The present invention is based on the above findings by the present inventors, and means for solving the above problems are as follows. That is,
<1> An electrophotographic photoreceptor having a support and a photosensitive layer comprising a charge generation layer and a charge transport layer on the support,
The charge transport layer contains a binder resin and a compound represented by the following general formula (1),
The binder resin is a polycarbonate copolymer represented by the following general formula (2):
Under an environment of a temperature of 22 ° C. and a relative humidity of 55% RH, using a Vickers square pyramid diamond indenter, a set load is 9.8 mN, and the elastic work modulus of the charge transport layer is 38% at an indentation depth of 1 μm from the surface of the charge transport layer. The electrophotographic photosensitive member is characterized by having a hardness of ˜48% and a universal hardness of 180 N / m ^{2 to} 200 N / m ² .
However, in said general formula (1), R < ¹ > -R < ⁴ > may mutually be the same, may differ, and a C1-C6 alkyl which may have a hydrogen atom and a substituent. Represents any of a group and an alkoxyl group having 1 to 6 carbon atoms which may have a substituent.
However, in said general formula (2), copolymerization molar ratio (m: n) is 35: 65-50: 50.
<2> The charge generation layer contains a charge generation agent, the charge generation agent is oxytitanium phthalocyanine, and the oxytitanium phthalocyanine has an X-ray diffraction Bragg angle 2θ diffraction peak (± 0.2) with respect to CuKα rays. The electrophotographic photosensitive member according to the above <1>, having a maximum diffraction angle of at least 27.2 ° and further having main peaks at 9.7 °, 14.2 °, 18.0 °, and 24.2 °. It is.
<3> The charge generation layer contains a charge generation agent, the charge generation agent is oxytitanium phthalocyanine, and the oxytitanium phthalocyanine has an X-ray diffraction Bragg angle 2θ diffraction peak (± 0.2 °) with respect to CuKα rays. , Having a maximum diffraction peak at least 27.2 °, and further having major peaks at 9.4 °, 9.6 °, and 24.0 °, and 7.3 as the lowest diffraction peak. The electrophotographic photosensitive member according to the above <1>, having a peak at °, no peak within a range of 7.4 ° or more and less than 9.4 °, and no peak at 26.3 °. .
<4> An electrophotographic photosensitive member, charging means for charging the surface of the electrophotographic photosensitive member, exposure means for exposing the charged electrophotographic photosensitive member surface to form an electrostatic latent image, and the electrostatic latent image An image forming apparatus comprising: a developing unit that develops a visible image by developing a toner; and a transfer unit that transfers the visible image to a recording medium.
An electrophotographic photosensitive member according to any one of <1> to <3>, wherein the electrophotographic photosensitive member is an image forming apparatus.
<5> The image forming apparatus according to <4>, wherein the image forming apparatus is an eraseless type image forming apparatus that does not have a charge removing unit that charges the surface of the electrophotographic photosensitive member.

  According to the present invention, the above-mentioned problems can be solved and the above-mentioned object can be achieved, and it is possible to cope with a process in which the diameter of the photoconductor is reduced and the peripheral speed is fast as the copying machine and the printer device are downsized and increased in speed. And an electrophotographic photosensitive member that is highly sensitive and responsive in a long wavelength range, has no deterioration in electrical characteristics even after repeated use, and has high wear resistance and cleaning properties, and the electrophotographic photosensitive member. An image forming apparatus can be provided.

1 is an X-ray diffraction pattern of oxytitanium phthalocyanine obtained in Synthesis Example 1. FIG. 2 is an X-ray diffraction pattern of oxytitanium phthalocyanine obtained in Synthesis Example 2. FIG. FIG. 3 is an X-ray diffraction pattern of α-type oxytitanium phthalocyanine obtained in Synthesis Example 3. 4 is an X-ray diffraction pattern of β-type oxytitanium phthalocyanine obtained in Synthesis Example 4. FIG. FIG. 5 is a schematic view showing an example of the image forming apparatus of the present invention. FIG. 6 is a schematic view showing another example of the image forming apparatus of the present invention.

(Electrophotographic photoreceptor)
The electrophotographic photoreceptor of the present invention comprises a support and a photosensitive layer comprising a charge generation layer and a charge transport layer on the support, and further comprises other layers as necessary.

  In the present invention, the electrophotographic photosensitive member is worn by contact with a recording medium (paper), a cleaning unit, a contact-type charging unit, and the like. In order to prevent this, it is important to optimize not only the composition of the charge transport layer but also the elastic power and universal hardness of the charge transport layer.

The elastic power of the charge transport layer is 38% to 48%, preferably 40% to 45%. If the elastic power is less than 38%, the printing durability may be lowered, and if it exceeds 48%, the cleaning property when the toner remaining on the electrophotographic photosensitive member is cleaned with a cleaning blade is lowered. There are things to do.
Universal hardness (HU) of the charge transport layer ^{is 180N / m 2 ~200N / m 2} , 190N / m 2 ~200N / m 2 is preferred. If the universal hardness is too low or too high, printing durability tends to decrease.

Here, the elastic power and the universal hardness can be measured as long as the device can measure the indenter movement amount and the indenter load when the diamond indenter is pressed against the object to be measured. Examples of the measurement of the elastic power and the universal hardness include a Fisher scope H-100 commercially available from Fisher Instruments, a dynamic micro hardness tester DUH-211 commercially available from SHIMADZU, and the like. Although depending on the measurement conditions of the elastic power, since the measurement is easily influenced by the lower layer (in the present invention, the support and the charge generation layer), the thickness of the measured object (in the present invention, the charge transport layer) is reduced. It is preferable to make it sufficiently thick. Specifically, the amount of displacement of the diamond indenter in the measurement of the elastic power is preferably 1/6 or less, more preferably 1/10 or less, of the thickness of the measured object.
The universal hardness of the charge transport layer represents the displacement of the indenter at the maximum load as a hardness value, and the elastic power can be calculated from a graph of a load-unloading test.

-Layer structure-
As the electrophotographic photosensitive member, a functional separation type having a support, a charge generation layer on the support, and a charge transport layer on the charge generation layer is used. The present invention can also be applied to a single layer type electrophotographic photoreceptor containing the same in the same layer.

<Support>
Examples of the support include those having a volume resistivity of 10 ¹⁰ Ω · cm or less, such as aluminum, brass, stainless steel, nickel, chromium, titanium, gold, silver, copper, tin, platinum, molybdenum, Examples thereof include a single metal such as indium or a processed body of an alloy thereof. The shape of the support may be any of a sheet shape, a film shape, a belt shape, a drum shape, and the like, and in the case of a belt-like support, it may be endless or endless. In the case of a drum-shaped support, the diameter is preferably 60 mm or less, and more preferably 30 mm or less.

  Among these, aluminum alloys such as JIS 3000 series, JIS 5000 series, and JIS 6000 series are preferably used, such as EI (Extension Ironing) method, ED (Extension Drawing) method, DI (Drawing Ironing) method, II (Impact Ironing) method and the like. The support formed by the general method is preferable, and further, the surface of the support is not subjected to surface treatment such as diamond cutting or polishing, surface treatment such as polishing, anodizing treatment, or the like. Any one such as a non-cutting tube may be used.

When a resin is used as the support, a conductive agent such as metal powder or conductive carbon can be contained in the resin, or a conductive resin can be used as the support forming resin.
When glass is used as the support, the surface thereof may be coated with tin oxide, indium oxide, or aluminum iodide to provide conductivity.

  A resin layer may be formed on the support. The resin layer has an adhesion improving function, a barrier function for preventing an inflow current from the aluminum tube, a defect covering function on the surface of the aluminum tube, and the like. Examples of the resin layer include various resins such as polyethylene resin, acrylic resin, epoxy resin, polycarbonate resin, polyurethane resin, vinyl chloride resin, vinyl acetate resin, polyvinyl butyral resin, polyamide resin, nylon resin, alkyd resin, and melamine resin. Can be used. These resin layers may be composed of a single resin or a mixture of two or more resins. Moreover, a metal compound, carbon, silica, resin powder, etc. can be dispersed in the resin layer. Furthermore, various pigments, electron accepting substances, electron donating substances, and the like can be included for improving the characteristics.

<Charge generation layer>
The charge generation layer contains a charge generation agent and a binder resin, and further contains other components as necessary.

-Charge generator-
Examples of the charge generator include oxytitanium phthalocyanine (specific crystal type oxytitanium phthalocyanine) having a maximum peak at a Bragg angle (2θ ± 0.2 °) of 27.2 ° in an X-ray diffraction spectrum using CuKα as a radiation source. Preferably used.
As such oxytitanium phthalocyanine having a maximum peak at a Bragg angle (2θ ± 0.2 °) of 27.2 °, as shown in FIG. 1, a diffraction peak (± 0 .2), oxytitanium phthalocyanine having a maximum diffraction angle of at least 27.2 ° and having major peaks at 9.7 °, 14.2 °, 18.0 °, and 24.2 ° This is preferable in terms of sensitivity.
Further, as shown in FIG. 2, the diffraction peak (± 0.2 °) of the X-ray diffraction Bragg angle 2θ with respect to the CuKα ray has a maximum diffraction peak at least 27.2 °, and further 9.4 °, 9 It has major peaks at .6 ° and 24.0 °, and has a peak at 7.3 ° as the lowest diffraction peak, and a peak in the range of 7.4 ° to less than 9.4 °. Oxytitanium phthalocyanine that does not have a peak and does not have a peak at 26.3 ° is preferable in terms of high sensitivity.

The specific crystal type oxytitanium phthalocyanine is not particularly limited and can be synthesized by a conventionally known method. For example, it can be synthesized by a method described in JP-A-2004-233465.
The content of the specific crystal type oxytitanium phthalocyanine in the charge generation layer is preferably 20% by mass to 95% by mass, and more preferably 50% by mass to 90% by mass.

  By using, as a charge generator, a specific crystal type oxytitanium phthalocyanine having a maximum peak at a Bragg angle (2θ ± 0.2 °) of 27.2 ° in an X-ray diffraction spectrum using CuKα as a radiation source. It is possible to provide an electrophotographic photosensitive member having excellent sensitivity in a wavelength region and exhibiting stable characteristics without being affected by the use environment, particularly humidity.

  In addition to the specific crystal type oxytitanium phthalocyanine, other oxytitanium phthalocyanine, other pigments such as an azo pigment, and the like are mixed in the charge generation layer in order to obtain an appropriate photosensitivity wavelength and sensitizing action. It can also be made. Examples of the other pigments include monoazo pigments, bisazo pigments, trisazo pigments, polyazo pigments, indigo pigments, selenium pigments, toluidine pigments, pyrazoline pigments, perylene pigments, quinacridone pigments, and pyrylium salts.

-Binder resin-
There is no restriction | limiting in particular as said binder resin, According to the objective, it can select suitably, For example, polycarbonate resin, polystyrene resin, acrylic resin, styrene-acrylic resin, ethylene-vinyl acetate resin, polypropylene resin, vinyl chloride resin , Chlorinated polyether, vinyl chloride-vinyl acetate resin, polyester resin, furan resin, nitrile resin, alkyd resin, polyacetal resin, polymethylpentene resin, polyamide resin, polyurethane resin, epoxy resin, polyarylate resin, diarylate resin, polysulfone Resin, polyethersulfone resin, polyarylsulfone resin, silicone resin, ketone resin, polyvinyl butyral resin, polyether resin, phenol resin, EVA (ethylene-vinyl acetate) resin, ACS Acrylonitrile - chlorinated polyethylene - styrene) resin, ABS (acrylonitrile - butadiene - styrene) such as resin. These may be used individually by 1 type and may use 2 or more types together. Among these, a mixture of resins having different molecular weights is preferable in terms of improving hardness and wear resistance.

  The method for forming the charge generation layer is not particularly limited, and various methods can be used. For example, the charge generation agent and the binder resin, and other components dispersed or dissolved in a solvent as necessary. The charge generation layer coating solution can be formed on a support and dried as necessary.

  There is no restriction | limiting in particular as said solvent, According to the objective, it can select suitably, For example, alcohols, such as methanol, ethanol, n-propanol, i-propanol, butanol; Pentane, hexane, heptane, octane, cyclohexane Saturated hydrocarbons such as cycloheptane; aromatic hydrocarbons such as toluene and xylene; halogenated hydrocarbons such as dichloromethane, dichloroethane, chloroform, and chlorobenzene; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; formic acid Esters such as ethyl, propyl formate, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, methyl propionate; diethyl ether, dimethoxyethane, tetrahydrofuran, dioxolane, dioxane, aniso Ether solvents like; N, N-dimethylformamide, and dimethyl sulfoxide. These may be used individually by 1 type and may use 2 or more types together. Among these, ketones, esters, ethers, and halogenated hydrocarbons are particularly preferable.

  Examples of the coating method include a dip coating method, a spray coating method, a bead coating method, a nozzle coating method, a spinner coating method, and a ring coating method. Drying after application is performed by heating using an oven or the like. The drying temperature of the charge generation layer is preferably 50 ° C to 160 ° C, and more preferably 80 ° C to 140 ° C.

  The thickness of the charge generation layer is not particularly limited and may be appropriately selected depending on the purpose. It is preferably 0.01 μm to 5 μm, and more preferably 0.1 μm to 2 μm.

<Charge transport layer>
The charge transport layer contains a binder resin and a compound represented by the following general formula (1) as a charge transport agent, and further contains other components as necessary.

-Charge transport agent-
The charge transfer agent contains a compound represented by the following general formula (1).
However, in said general formula (1), R < ¹ > -R < ⁴ > may mutually be the same, may differ, and a C1-C6 alkyl which may have a hydrogen atom and a substituent. Represents any of a group and an alkoxyl group having 1 to 6 carbon atoms which may have a substituent.
Examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, a propyl group, and a butyl group.
As said C1-C6 alkoxyl group, a methoxy group, an ethoxy group, a propoxy group, a butoxy group etc. are mentioned, for example.
Examples of the substituent in the alkyl group and alkoxy group include an aryloxy group such as a halogen atom, a nitro group, a cyano group, and a phenoxy group, an aryl group such as a phenyl group and a naphthyl group, and an aralkyl group such as a benzyl group and a phenethyl group. Etc.

  The compound represented by the general formula (1) as the charge transport agent has good compatibility with the specific crystal type oxytitanium phthalocyanine as the charge generator, high sensitivity, and excellent responsiveness. A photoreceptor can be provided.

  Hereinafter, although the specific example of a compound represented by the said General formula (1) is shown, it is not limited to these.

As the compound represented by the general formula (1), an appropriately synthesized product or a commercially available product may be used.
There is no restriction | limiting in particular as said synthesis method, According to the objective, it can select suitably, For example, the synthesis method etc. which are described in Unexamined-Japanese-Patent No. 59-216853 etc. are mentioned.

  30 mass parts-90 mass parts are preferable with respect to 100 mass parts of binder resins mentioned later, and, as for content of the compound represented by the said General formula (1) in the said charge transport layer, 40 mass parts-80 mass parts are. More preferred. When the content is less than 30 parts by mass, electrical characteristics such as an increase in residual potential may be deteriorated, and when it exceeds 90 parts by mass, mechanical characteristics such as wear resistance may be deteriorated.

In addition, the compound represented by the general formula (1) and, if necessary, other charge transport agents can be mixed and used. In this case, the mass ratio of the compound represented by the general formula (1) and the other charge transporting agent (compound represented by the general formula (1): other charge transporting agent) is 50:50 to 95: 5 is preferable, and 70:30 to 95: 5 is preferable.
The other charge transfer agent may be a high molecular compound or a low molecular compound.
Examples of the polymer compound include polyvinyl carbazole, halogenated polyvinyl carbazole, polyvinyl pyrene, polyvinyl indoloquinoxaline, polyvinyl benzothiophene, polyvinyl anthracene, polyvinyl acridine, polyvinyl pyrazoline, polyacetylene, polythiophene, polypyrrole, polyphenylene, polyphenylene vinylene, Examples thereof include conductive polymer compounds such as polyisothianaphthene, polyaniline, polydiacetylene, polyheptadiene, polypyridinediyl, polyquinoline, polyphenylene sulfide, polyferrocenylene, polyperinaphthylene, and polyphthalocyanine.
Examples of the low molecular weight compound include trinitrofluorenone, tetracyanoethylene, tetracyanoquinodimethane, quinone, diphenoquinone, naphthoquinone, anthraquinone or derivatives thereof, anthracene, pyrene, phenanthrene, etc .; indole, carbazole And nitrogen-containing heterocyclic compounds such as imidazole; fluorenone, fluorene, oxadiazole, oxazole, pyrazoline, hydrazone, triphenylmethane, triphenylamine, enamine, stilbene and the like.
Further, a polymer solid electrolyte in which a polymer compound such as polyethylene oxide, polypropylene oxide, polyacrylonitrile, polymethacrylic acid or the like is doped with a metal ion such as Li ion can also be used. Furthermore, an organic charge transfer complex formed of an electron donating compound typified by tetrathiafulvalene-tetracyanoquinodimethane and an electron accepting compound can also be used. These may be used individually by 1 type and may use 2 or more types together.

-Binder resin-
As the binder resin, a polycarbonate copolymer represented by the following general formula (2) is used.
In the said General formula (2), copolymerization molar ratio (m: n) is 35: 65-50: 50, and 38: 62-45: 55 is preferable. When m in the copolymer molar ratio (m: n) is less than 35 mol%, the printing durability of the photoreceptor may be deteriorated. When it exceeds 50 mol%, the binder resin and the charge transport agent are uniform. It may become opaque without dissolving.

Examples of the polycarbonate copolymer represented by the general formula (2) include, but are not limited to, the following.

The polycarbonate copolymer represented by the general formula (2) is not particularly limited, and can take any form of a random copolymer, a block copolymer, an alternating copolymer, and a composite thereof.
There is no restriction | limiting in particular as a synthesis method of the polycarbonate copolymer represented by the said General formula (2), According to the objective, it can select suitably, For example, (1) Dihydric phenol (1,1-bis) (4-bidoxyphenyl) cyclohexane or 4,4′-dihydroxybiphenyl) is reacted with phosgene to produce a polycarbonate oligomer, and then the divalent phenol is added to the polycarbonate oligomer with the solvent and acid binder. Examples include a method of polycondensation reaction in the presence of a mixed solution of an alkaline aqueous solution, and (2) a method of polycondensation reaction of the dihydric phenol and phosgene in a mixed solution of the solvent and an alkaline aqueous solution. Among these, the method (1) for producing a polycarbonate oligomer in advance is particularly preferable in that it is efficient.

In order to produce the polycarbonate oligomer, first, a dihydric phenol (1,1-bis (4-bidroxyphenyl) cyclohexane or 4,4′-dihydroxybiphenyl) is dissolved in an alkaline aqueous solution, and an alkaline aqueous solution of the dihydric phenol is obtained. To prepare. Next, this alkaline aqueous solution is reacted with phosgene in the presence of an organic solvent such as methylene chloride to synthesize a polycarbonate oligomer of a dihydric phenol. Next, the reaction solution is separated into an aqueous phase and an organic phase to obtain an organic phase containing a polycarbonate oligomer. At this time, the alkali concentration of the aqueous alkali solution may be a concentration at which the aqueous phase becomes alkaline.
The reaction temperature is usually 0 ° C. to 70 ° C., and the reaction time is about 1 minute to 4 hours.

The dihydric phenol is added to the organic phase containing the polycarbonate oligomer thus obtained and reacted. The reaction temperature is usually 0 ° C to 35 ° C.
The reaction pressure can be any of reduced pressure, normal pressure, and increased pressure. Usually, it can be suitably performed at normal pressure or about the self-pressure of the reaction system. The reaction time depends on the reaction temperature and the like, but is usually about 0.5 minutes to 10 hours.
The polycondensation reaction is preferably carried out in an inert gas atmosphere such as nitrogen or argon.

  In addition to the polycarbonate copolymer represented by the general formula (2), other resins can be mixed and used as necessary as the binder resin. There is no restriction | limiting in particular as said other resin, According to the objective, it can select suitably, For example, a polystyrene resin, a styrene-acrylonitrile copolymer, a styrene-butadiene copolymer, a styrene-maleic anhydride copolymer Polycarbonate resins other than the polycarbonate copolymer represented by the general formula (2), polyester resin, methacrylic resin, acrylic resin, polyethylene resin, polyvinyl chloride resin, polyvinyl acetate resin, phenol resin, epoxy resin, polyurethane resin , Polyvinylidene chloride resin, alkyd resin, silicone resin, polyvinyl carbazole resin, polyvinyl butyral resin, polyvinyl formal resin, polyacrylate resin, polyacrylamide resin, phenoxy resin and the like. These may be used individually by 1 type and may use 2 or more types together.

The method for forming the charge transport layer is not particularly limited, and various methods can be used. For example, the charge transport agent and the binder resin, and other components dispersed or dissolved in a solvent as required. A method of applying the charge transport layer coating liquid onto the base charge generation layer and drying it can be used.
The solvent and the coating method can be the same as those for the charge generation layer.

  There is no restriction | limiting in particular in the average thickness of the said charge transport layer, According to the objective, it can select suitably, 5 micrometers-100 micrometers are preferable, and 15 micrometers-40 micrometers are more preferable.

<Other layers>
In the electrophotographic photoreceptor of the present invention, a protective layer can be provided on the charge transport layer for the purpose of protecting the undercoat layer and the surface between the support and the charge generation layer. In addition, a blocking layer can be provided between the support and the charge generation layer.

-Undercoat layer-
The undercoat layer contains a binder resin and fine particles, and further contains other components as necessary.
The binder resin is not particularly limited and may be appropriately selected depending on the intended purpose. For example, polyamide resin, phenol resin, casein, melamine resin, benzoguanamine resin, polyurethane resin, epoxy resin, cellulose, nitrocellulose, polyvinyl Examples include alcohol resins and polyvinyl butyral resins. These may be used individually by 1 type and may use 2 or more types together. The binder resin used for the undercoat layer may be a polycarbonate copolymer that is a binder resin for the charge transport layer.
Examples of the fine particles include titanium oxide, aluminum oxide, zirconia, titanic acid, zirconic acid, lanthanum lead, titanium black, silica, lead titanate, barium titanate, tin oxide, indium oxide, and silicon oxide. These may be used individually by 1 type and may use 2 or more types together.
The method for forming the undercoat layer is not particularly limited, and various methods can be used. For example, an undercoat in which the binder resin, the fine particles, and other components as necessary are dispersed or dissolved in a solvent. A method of applying a layer coating solution on a support and drying it can be used.
The solvent and the coating method can be the same as those for the charge generation layer.
The average thickness of the undercoat layer is preferably 0.01 μm to 10 μm, more preferably 0.1 μm to 7 μm.

The electrophotographic photoreceptor of the present invention has an antioxidant, an ultraviolet absorber, a radical scavenger, a softener, a curing agent in each layer such as a charge generation layer, a charge transport layer, an undercoat layer, and a protective layer as long as the characteristics are not impaired. An agent, a crosslinking agent, or the like can be added to improve the characteristics, durability, and mechanical properties of the photoreceptor. Among these, the use of an antioxidant and an ultraviolet absorber alone or in combination is particularly preferable because it can contribute to improving the durability of the photoreceptor.
Examples of the antioxidant include phenol-based antioxidants, amine-based antioxidants, and sulfur-based antioxidants.

  Examples of the phenolic antioxidant include 2,6-di-tert-butylphenol, 2,6-di-tert-4-methoxyphenol, 2-tert-butyl-4-methoxyphenol, and 2,4-dimethyl. -6-tert-butylphenol, 2,6-di-tert-butyl-4-methylphenol, butylated hydroxyanisole, stearyl propionate-β- (3,5-di-tert-butyl-4-hydroxyphenyl), monophenolic antioxidants such as α-tocopherol, β-tocopherol, n-octadecyl-3- (3′-5′-di-tert-butyl-4′-hydroxyphenyl) propionate; 2.2′-methylenebis ( 6-tert-butyl-4-methylphenol), 4,4′-butylidene-bis- (3- Til-6-tert-butylphenol), 4,4′-thiobis (6-tert-butyl-3-methylphenol), 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) ) Butane, 1,3,5-trimethyl-2,4,6-tris (3.5-di-tert-butyl-4-hydroxybenzyl) benzene, tetrakis [methylene-3 (3,5-di-tert- Butyl-4-hydroxyphenyl) propionate] polyphenol antioxidants such as methane. These may be used individually by 1 type and may use 2 or more types together.

  Examples of the amine antioxidant include α, α ′ (tetrabenzyl) diamino-P-xylene, N-phenyl-1-naphthylamine, N-phenyl-N′-isopropyl-p-phenylenediamine, and N, N. -Diethyl-p-phenylenediamine, N-phenyl-N'-ethyl-2-methyl-p-phenylenediamine, N-ethyl-N-hydroxyethyl-p-phenylenediamine, alkylated diphenylamine, N, N'-diphenyl -P-phenylenediamine, N, N'-diallyl-p-phenylenediamine, N-phenyl-1,3-dimethylbutyl-p-phenylenediamine, 4,4'-dioctyl-diphenylamine, 4,4'-dioctyl- Diphenylamine, 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline 2,2,4-trimethyl-1,2-dihydroquinoline, N-phenyl-β-naphthylamine, N, N′-di-2-naphthyl-p-phenylenediamine, and the like. These may be used individually by 1 type and may use 2 or more types together.

  Examples of the sulfur-based antioxidant include dilauryl-3,3-thiodipropionate, ditridecyl-3,3-thiodipropionate, dimyristyl-3,3-thiodipropionate, and distearyl-3,3. -Thiodipropionate, lauryl stearyl-3,3-thiopropionate, bis [2-methyl-4- (3-n-alkyl C12-C14) thiopropionate) -5-t-butylphenyl] sulfide Pentaerythritol tetra (β-lauryl-thiopropionate) ester, 2-mercaptobenzimidazole, 2-mercapto-6-methylbenzimidazole, and the like. These may be used individually by 1 type and may use 2 or more types together.

  The addition amount of the phenolic antioxidant is preferably 1% by mass to 20% by mass with respect to the binder resin of the layer to which the phenolic antioxidant is added. The addition amount of the amine antioxidant is preferably 1% by mass to 20% by mass with respect to the binder resin of the layer to which the amine antioxidant is added. The addition amount of the sulfur-based antioxidant is preferably 0.1% by mass to 5% by mass with respect to the binder resin of the layer to which the sulfur-based antioxidant is added.

As said ultraviolet absorber, a benzotriazole type ultraviolet absorber, a salicylic acid type ultraviolet absorber, etc. are mentioned, for example.
Examples of the benzotriazole ultraviolet absorber include 2- (5-methyl-2-hydroxyphenyl) benzotriazole, 2- [2-hydroxy-3,5-bis (α, α-dimethylbenzyl) phenyl]- 2H-benzotriazole, 2- (3,5-di-tert-butyl-2-hydroxyphenyl) benzotriazole, 2- (3-tert-butyl-5-methyl-2-hydroxyphenyl) -5-chlorobenzotriazole 2- (3,5-di-tert-butyl-2-hydroxyphenyl) -5-chlorobenzotriazole, 2- (3,5-di-tert-amyl-2-hydroxyphenyl) benzotriazole, 2- ( 2′-hydroxy-5′-tert-octylphenyl) benzotriazole, 2- (2-hydroxy-5-methyl) Butylphenyl) benzotriazole and the like. These may be used individually by 1 type and may use 2 or more types together.
Examples of the salicylic acid ultraviolet absorber include phenyl salicylate, salicylic acid-p-tert-butylphenyl, salicylic acid-p-octylphenyl, and the like. These may be used individually by 1 type and may use 2 or more types together.
The addition amount of the ultraviolet absorber is preferably 1% by mass to 20% by mass with respect to the binder resin of the layer to which the ultraviolet absorber is added.

(Image forming apparatus and image forming method)
The image forming apparatus of the present invention comprises at least an electrophotographic photosensitive member, a charging unit, an exposure unit, a developing unit, and a transfer unit, a fixing unit, and other units appropriately selected as necessary. For example, it comprises a cleaning means, a static elimination means, a recycling means, a control means and the like. The charging unit and the exposure unit may be collectively referred to as an electrostatic latent image forming unit.
The image forming method used in the present invention includes at least a charging step, an exposure step, a development step, and a transfer step, a fixing step, and other steps appropriately selected as necessary, for example, a cleaning step, a static elimination step, and the like. Includes processes, recycling processes, control processes, etc. The charging process and the exposure process may be collectively referred to as an electrostatic latent image forming process.

<Electrophotographic photoreceptor>
As the electrophotographic photoreceptor, the electrophotographic photoreceptor of the present invention is used.

<Charging step and charging means>
The charging step is a step of charging the surface of the electrophotographic photosensitive member, and is performed by a charging unit. The charging means is not particularly limited and may be appropriately selected depending on the intended purpose.For example, a charger equipped with a conductive or semiconductive roll, brush, film, rubber blade, corotron, Examples include a charger using corona discharge such as a scorotron.

<Exposure process and exposure means>
The exposure (writing) can be performed, for example, by exposing the surface of the electrophotographic photosensitive member imagewise using the exposure unit.
The exposure unit is not particularly limited as long as the surface of the electrophotographic photosensitive member charged by the charging unit can be exposed like an image to be formed, and can be appropriately selected according to the purpose. However, there are various exposure devices such as a copying optical system, a rod lens array system, a laser optical system, a liquid crystal shutter optical system, and an LED optical system.
In the present invention, an optical backside system that performs imagewise exposure from the backside of the electrophotographic photosensitive member may be employed.
As the light source, for example, a light source capable of ensuring high luminance such as a light emitting diode (LED), a semiconductor laser (LD), and electroluminescence (EL) is used.

<Development process and development means>
The developing step is a step of developing the electrostatic latent image using a toner or a developer to form a visible image.
The visible image can be formed, for example, by developing the electrostatic latent image using the toner or the developer, and can be performed by the developing unit.
The developing unit is not particularly limited as long as it can be developed using, for example, the toner or the developer, and can be appropriately selected from known ones. For example, the toner or developer is accommodated. Preferred examples include those having at least a developing unit capable of bringing the toner or developer into contact or non-contact with the electrostatic latent image.

  The developing unit may be a dry developing type, a wet developing type, a single color developing unit, or a multi-color developing unit. For example, a toner having a stirrer for charging the toner or the developer by frictional stirring and a rotatable magnet roller is preferable.

In the developing device, for example, the toner and the carrier are mixed and agitated, and the toner is charged by friction at that time, and held on the surface of the rotating magnet roller in a raised state to form a magnetic brush. . Since the magnet roller is disposed in the vicinity of the electrophotographic photosensitive member, a part of the toner constituting the magnetic brush formed on the surface of the magnet roller is electrically attracted to the electrophotographic photosensitive member. Move to the surface of the body. As a result, the electrostatic latent image is developed with the toner to form a visible image with the toner on the surface of the electrophotographic photosensitive member.
The developer accommodated in the developing device may be a one-component developer or a two-component developer.

<Transfer process and transfer means>
The transfer step is a step of transferring the visible image onto a recording medium. After the primary transfer of the visible image onto the intermediate transfer member using an intermediate transfer member, the visible image is transferred onto the recording medium. A primary transfer step of forming a composite transfer image by transferring a visible image onto an intermediate transfer body using two or more colors, preferably full color toner as the toner, and a composite transfer image; A mode including a secondary transfer step of transferring the transfer image onto the recording medium is more preferable.
The transfer can be performed, for example, by charging the visible image with the electrophotographic photosensitive member using a transfer charger, and can be performed by the transfer unit. The transfer means includes a primary transfer means for transferring a visible image onto an intermediate transfer member to form a composite transfer image, and a secondary transfer means for transferring the composite transfer image onto a recording medium. Embodiments are preferred.
The intermediate transfer member is not particularly limited and may be appropriately selected from known transfer members according to the purpose. For example, a transfer belt and the like are preferable.

The transfer unit (the primary transfer unit and the secondary transfer unit) includes at least a transfer unit that peels and charges the visible image formed on the electrophotographic photosensitive member toward the recording medium. preferable. There may be one transfer means or two or more transfer means. Examples of the transfer device include a corona transfer device using corona discharge, a transfer belt, a transfer roller, a pressure transfer roller, and an adhesive transfer device.
The recording medium is typically plain paper, but is not particularly limited as long as it can transfer an unfixed image after development, and can be appropriately selected according to the purpose. PET for OHP A base or the like can also be used.

<Fixing process and fixing means>
The fixing step is a step of fixing the toner image transferred to the recording medium, and can be fixed using a fixing unit. When two or more color toners are used, the toner may be fixed each time the toner of each color is transferred to the recording medium, or the toner of all colors may be transferred to the recording medium and fixed in a stacked state. Also good. The fixing unit is not particularly limited, and a heat fixing method using a known heating and pressing unit can be employed. Examples of the heating and pressing means include a combination of a heating roller and a pressure roller, and a combination of a heating roller, a pressure roller, and an endless belt. At this time, heating temperature is 80 degreeC-200 degreeC normally. If necessary, for example, a known optical fixing device may be used together with the fixing means.

<Other processes and other means>
-Static elimination process and static elimination means-
The neutralization step is a step of performing neutralization by applying a neutralization bias to the electrophotographic photosensitive member, and can be suitably performed by a neutralization unit.
The neutralization means is not particularly limited, and may be appropriately selected from known neutralizers as long as it can apply a neutralization bias to the electrophotographic photosensitive member. For example, a neutralization lamp is preferably used. Can be mentioned.
Note that the erase-less image forming apparatus is not provided with the charge eliminating unit. Thereby, the diameter of the photoconductor can be reduced, and the downsizing of the image forming apparatus can be achieved.

-Cleaning process and cleaning means-
The cleaning step is a step of removing the toner remaining on the electrophotographic photosensitive member, and can be suitably performed by a cleaning unit.
The cleaning means is not particularly limited as long as the toner remaining on the electrophotographic photosensitive member can be removed, and can be appropriately selected from known cleaners. For example, a magnetic brush cleaner, a static cleaner Preferred examples include an electric brush cleaner, a magnetic roller cleaner, a blade cleaner, a brush cleaner, and a web cleaner.

-Recycling process and recycling means-
The recycling step is a step of recycling the toner removed by the cleaning step to the developing unit, and can be suitably performed by the recycling unit.
There is no restriction | limiting in particular as said recycling means, A well-known conveyance means etc. are mentioned.

-Control process and control means-
The control step is a step of controlling each of the steps, and can be suitably performed by a control unit.
The control means is not particularly limited as long as the movement of each means can be controlled, and can be appropriately selected according to the purpose. Examples thereof include devices such as a sequencer and a computer.

Here, an example of the image forming apparatus of the present invention will be described with reference to the drawings. FIG. 5 is a schematic configuration diagram showing an example of an electrophotographic image forming apparatus according to the present invention.
In FIG. 5, reference numeral 11 denotes an electrophotographic photosensitive member, and a charging unit 12 is provided in contact with the electrophotographic photosensitive member. The charging means 12 is supplied with a voltage from a power source 13.
Around the electrophotographic photoreceptor 11, an exposure unit 14, a developing unit 15, a primary transfer unit 16, a cleaning unit 19, and a charge eliminating unit 21 are provided. Reference numeral 22 denotes fixing means. FIG. 6 is a schematic configuration diagram illustrating an example of an eraseless image forming apparatus according to the present invention. The image forming apparatus illustrated in FIG. 5 has the same structure except that the charge eliminating unit 21 is not provided. Therefore, the same reference numerals are attached and the description thereof is omitted.

As the electrophotographic photoreceptor 11, the electrophotographic photoreceptor of the present invention is used. The electrophotographic photosensitive member has a drum shape, but may be a sheet shape or an endless belt shape.
As the charging unit 12, a non-contact roller-shaped charger is used. The surface of the electrophotographic photoreceptor 11 is charged by this charger.
For the exposure means 14, a light source capable of ensuring high brightness such as a light emitting diode (LED), a semiconductor laser (LD), or electroluminescence (EL) is used. Of these light sources, light emitting diodes and semiconductor lasers are used favorably because of their high irradiation energy.
The developing means 15 has at least one developing sleeve. The developing means 15 uses toner and develops the electrostatic latent image. There are two methods, a one-component method in which development is performed with toner alone and a two-component method in which a two-component developer comprising a toner and a carrier is used. Either method can be used favorably.

The primary transfer means (primary transfer belt) 16 has a primary transfer roller 17, and the primary transfer roller 17 is supplied with a voltage by a constant voltage power supply 18. That is, transfer is performed by applying constant voltage control.
Reference numeral 20 denotes secondary transfer means for transferring the toner image on the primary transfer belt 16 onto a recording medium (paper) 23.
If toner remains on the electrophotographic photosensitive member 11 after the transfer, the residual toner is removed from the electrophotographic photosensitive member 11 by the fur brush and blade of the cleaning means 19. Cleaning may be performed only with a cleaning brush, and a fur brush, a mag fur brush, or the like is used as the cleaning brush.

  The image forming means described above may be fixedly incorporated in a copying apparatus, a facsimile machine, or a printer, but may be detachably incorporated in the image forming apparatus main body in the form of a process cartridge.

  Examples of the present invention will be described below, but the present invention is not limited to these examples.

(Synthesis example 1 of phthalocyanine)
Into a mixture of 64.4 g of phthalodinitrile and 150 mL of 1-methylnaphthalene, 6.5 mL of titanium tetrachloride was dropped for 5 minutes under a nitrogen stream. After dropping, the reaction was completed by heating at 200 ° C. for 2 hours with a mantle heater. Thereafter, the precipitate was filtered, and the filtration residue was washed with 1-methylnaphthalene, then with acetone, and further with methanol. Thereafter, a hydrolysis reaction was carried out at a boiling point for 10 hours with a mixed solution of 60 mL of concentrated aqueous ammonia and 60 mL of ion-exchanged water, followed by suction filtration at room temperature and washing with ion-exchanged water until the washing water became neutral. Then, after washing with methanol and drying with hot air at 90 ° C. for 10 hours, 64.6 g of a blue-violet crystalline titanyl phthalocyanine powder was obtained.
Next, 10 g of crystalline titanyl phthalocyanine powder was slowly dissolved in about 10 times the amount of concentrated sulfuric acid at 2 ° C., and then poured into 2,000 mL of ice water to precipitate crystals. After filtering the precipitated crystals, 5 g of the wet cake separated by filtration was put into 150 mL of water, 10 g of naphthalene was added, and the liquid temperature was stirred at 90 ° C. for 1 hour. Thereafter, after returning to room temperature, the mixture was filtered to obtain 9.5 g of oxytitanium phthalocyanine of Synthesis Example 1.

(Synthesis example 2 of phthalocyanine)
292 parts by mass of 1,3-diiminoisoindoline and 1,800 parts by mass of sulfolane were mixed, and 204 parts by mass of titanium tetrabutoxide was added dropwise under a nitrogen stream. After completion of the dropwise addition, the temperature was gradually raised to 180 ° C., and the reaction was carried out by stirring for 5 hours while maintaining the reaction temperature between 170 ° C. and 180 ° C. After the reaction is completed, the mixture is allowed to cool, and then the precipitate is filtered, washed with acetone until the powder turns blue, then washed several times with methanol, further washed several times with hot water at 80 ° C. and dried. Crude titanyl phthalocyanine was obtained.
60 parts by mass of the obtained crude titanyl phthalocyanine pigment subjected to the hot water washing treatment was stirred and dissolved in 1,000 parts by mass of 96% by mass sulfuric acid at 3 ° C. to 5 ° C. and filtered. The obtained sulfuric acid solution was added dropwise to 35,000 parts by mass of ice water with stirring, the precipitated crystals were filtered, and then washed with water until the washing solution became neutral to obtain an aqueous paste of titanyl phthalocyanine pigment.
1,500 parts by mass of tetrahydrofuran was added to this water paste, and the mixture was stirred at room temperature. When the dark blue color of the paste changed to light blue, the stirring was stopped and immediately filtered under reduced pressure. The crystals obtained on the filtration device were washed with tetrahydrofuran to obtain 98 parts by mass of a pigment wet cake. This was dried under reduced pressure (5 mmHg) at 70 ° C. for 2 days to obtain 78 parts by mass of oxytitanium phthalocyanine of Synthesis Example 2.

(Synthesis example 3 of phthalocyanine)
200 g (156 mmol) of o-phthalodinitrile, 146.1 g (42.9 mmol) of titanium tetrabutoxide, o-methylisourea sulfate (OMIU) as a base catalyst, and triethylene glycol monomethyl ether (MTG) as a reaction solvent The mixture with 160 mL was heated and stirred at 150 ° C. for 5 hours. Thereafter, the mixture was cooled, 100 mL of methanol was added, and filtered at 60 ° C. when warm. Then, it was washed with methanol and acetone to obtain a crude cake.
Next, 1,000 mL of dimethylformamide was added, and the suspension was heated and washed at 100 ° C. for 30 minutes, cooled, and then washed with methanol and acetone to obtain crude titanium phthalocyanine.
Thereafter, 60 parts by mass of the crude titanium phthalocyanine pigment subjected to the hot water washing treatment was stirred, dissolved in 1,000 parts by mass of 96% sulfuric acid at 3 ° C to 5 ° C, and filtered. The obtained sulfuric acid solution was dropped into 35,000 parts by mass of ice water with stirring, and the precipitated crystals were filtered. Next, washing with water was repeated until the washing solution became neutral, filtered and dried to obtain α-type oxytitanium phthalocyanine of Synthesis Example 3.

(Synthesis example 4 of phthalocyanine)
Into a mixture of 64.4 g of phthalodinitrile and 150 mL of 1-methylnaphthalene, 6.5 mL of titanium tetrachloride was dropped for 5 minutes under a nitrogen stream. After dropping, the reaction was completed by heating at 200 ° C. for 2 hours with a mantle heater. Thereafter, the precipitate was filtered, and the filtration residue was washed with 1-methylnaphthalene, then with acetone, and further with methanol. Thereafter, a hydrolysis reaction was carried out at a boiling point for 10 hours with a mixed solution of 60 mL of concentrated aqueous ammonia and 60 mL of ion-exchanged water, followed by suction filtration at room temperature and washing with ion-exchanged water until the washing water became neutral. Then, after washing with methanol and drying with hot air at 90 ° C. for 10 hours, 64.6 g of a blue-violet crystalline titanyl phthalocyanine powder was obtained. The crystalline titanyl phthalocyanine powder was washed with dichlorotoluene at 200 ° C. for 1 hour, and the powder obtained by filtration was washed with methanol and dried with hot air at 90 ° C. for 10 hours. Oxytitanium phthalocyanine was obtained.

<X-ray diffraction>
Oxytitanium phthalocyanine was attached to a silicon non-reflective plate, which was air-dried to obtain a specimen sample for X-ray diffraction. When measuring a specimen sample, it measured by the powder method, and measured using CuK (alpha) (wavelength 1.54178?) As an X-ray source. Measurement conditions are as follows.
X-ray diffractometer: X'Pert manufactured by Flipx Corporation
Measurement conditions: X-ray tube Cu
: Scanning range 4 ° to 35 °
: Tube voltage 45kV
: Tube current 40mA
: Step angle 0.01 degrees
: Counting time 20 seconds
: Reception slit, Divergence slit Variable type
: Irradiation width 20mm

  An X-ray diffraction pattern of the oxytitanium phthalocyanine obtained in Synthesis Example 1 of phthalocyanine is shown in FIG. According to FIG. 1, the oxytitanium phthalocyanine of Synthesis Example 1 has a maximum diffraction angle of 27.2 ° as a diffraction peak (± 0.2 °) with a Bragg angle 2θ, and further 9.7 °, 14.2 It was confirmed to have main peaks at °, 18.0 °, and 24.2 °.

  An X-ray diffraction pattern of the titanyl phthalocyanine obtained in Synthesis Example 2 of phthalocyanine is shown in FIG. According to FIG. 2, the titanyl phthalocyanine of Synthesis Example 2 has a maximum diffraction peak at 27.2 ° as a diffraction peak (± 0.2 °) with a Bragg angle 2θ, and further 9.4 °, 9.6. It has a major peak at ° and 24.0 °, a peak at 7.3 ° as the lowest diffraction peak, and a peak in the range of 7.4 ° to less than 9.4 °. Furthermore, it was confirmed that there was no peak at 26.3 °.

  An X-ray diffraction pattern of the α-type oxytitanium phthalocyanine obtained in Synthesis Example 3 of phthalocyanine is shown in FIG. According to FIG. 3, the α-type oxytitanium phthalocyanine of Synthesis Example 3 exhibits characteristic diffraction peaks at 7.6 ° and 28.6 ° as diffraction peaks (± 0.2 °) with a Bragg angle 2θ. It was confirmed that diffraction peaks were also observed at 10.3 °, 12.6 °, 18.4 °, 22.6 °, and 25.4 °.

  An X-ray diffraction pattern of β-type oxytitanium phthalocyanine obtained in Synthesis Example 4 of phthalocyanine is shown in FIG. According to FIG. 4, β-type oxytitanium phthalocyanine of Synthesis Example 4 shows a characteristic diffraction peak at 26.2 ° as a diffraction peak (± 0.2 °) with a Bragg angle 2θ of 10.5 °. , 13.1 °, 20.7 °, and 23.2 ° were confirmed to have diffraction peaks.

Example 1
<Production of electrophotographic photoreceptor>
<< Formation of undercoat layer >>
An undercoat layer coating solution prepared as follows was applied onto a cylindrical drum made of aluminum having a diameter of 30 mm as a support, and an undercoat layer having a thickness of 1.5 μm after drying was formed.
-Preparation of coating solution for undercoat layer-
Mixing of alkyd resin (Beckolite M-6401-50, manufactured by DIC Corporation) and amino resin (Super Becamine G-821-60, manufactured by DIC Corporation) at a ratio of 65:35 (mass ratio) A resin was prepared. This mixed resin and titanium oxide (CR-EL, manufactured by Ishihara Sangyo Co., Ltd.) are mixed so as to be 1: 3 (mass ratio), and a mixed liquid having a mass ratio of total solid content to methyl ethyl ketone of 1: 1 is obtained. The undercoat layer coating solution was prepared by dispersion treatment.

<< Formation of Charge Generation Layer >>
Next, using the charge generation layer coating solution prepared as follows, the support on which the undercoat layer is formed is dip coated and dried to form a 0.2 μm thick charge generation layer on the undercoat layer. Formed.
-Preparation of charge generation layer coating solution-
To 10 g of the oxytitanium phthalocyanine powder obtained in Synthesis Example 1 as a charge generator, a solution of 10 g of polyvinyl butyral resin (BM-1, manufactured by Sekisui Chemical Co., Ltd.) in 500 mL of methyl ethyl ketone is added, and glass beads are added. Dispersion was carried out for 20 hours with a sand mill disperser, and the resulting dispersion was filtered to remove the glass beads to prepare a charge generation layer coating solution.

<< Formation of charge transport layer >>
Next, using the charge transport layer coating solution prepared as follows, the support on which the charge generation layer and the undercoat layer are formed is dip coated, dried at 120 ° C. for 60 minutes, and the thickness is formed on the charge generation layer. A 25.0 μm charge transport layer was formed. Thus, the electrophotographic photosensitive member of Example 1 was produced.
-Preparation of charge transport layer coating solution-
As a binder resin, a polycarbonate copolymer No. 1 represented by the following chemical formula: 2-2 (copolymerization molar ratio (m: n) = 40: 60) and exemplified compound No. 2 represented by the following structural formula as a charge transfer agent. 1-1, 2,6-di-tert-butyl-4-methylphenol as an antioxidant, and 2- (2-hydroxy-5-methylphenyl) benzotriazole (Tinvin-P, Geigy) as an ultraviolet absorber Made by mass ratio (polycarbonate copolymer No. 2-2: Exemplified Compound No. 1-1: 2,6-di-tert-butyl-4-methylphenol: Tinuvin-P) is 100: 60: It mixed so that it might become 1.5: 1.5, 80 mass parts of tetrahydrofuran was added with respect to 20 mass parts of these solid content, and it stirred and melt | dissolved, and prepared the charge transport layer coating liquid.

(Example 2)
-Production of electrophotographic photoreceptor-
In Example 1, in the preparation of the charge transport layer coating solution, the polycarbonate copolymer No. 1 represented by the above chemical formula as the binder resin was used. 2-2 is a polycarbonate copolymer No. 2 represented by the following chemical formula. An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that it was changed to 2-1 (copolymerization molar ratio (m: n) = 35: 65).

(Example 3)
-Production of electrophotographic photoreceptor-
In Example 1, in the preparation of the charge transport layer coating solution, the polycarbonate copolymer No. 1 represented by the above chemical formula as the binder resin was used. 2-2 is a polycarbonate copolymer No. 2 represented by the following chemical formula. An electrophotographic photosensitive member was produced in the same manner as in Example 1, except that the ratio was changed to 2-3 (copolymerization molar ratio (m: n) = 50: 50).

Example 4
-Production of electrophotographic photoreceptor-
In Example 1, Exemplified Compound No. 1 was used as the charge transport agent in the preparation of the charge transport layer coating solution. 1-1 is exemplified compound No. 1 represented by the following structural formula. An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that it was replaced with 1-2.

(Example 5)
-Production of electrophotographic photoreceptor-
In Example 1, Exemplified Compound No. 1 was used as the charge transport agent in the preparation of the charge transport layer coating solution. 1-1 is exemplified compound No. 1 represented by the following structural formula. An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that it was replaced with 1-3.

(Example 6)
-Production of electrophotographic photoreceptor-
In Example 1, Exemplified Compound No. 1 was used as the charge transport agent in the preparation of the charge transport layer coating solution. 1-1 is exemplified compound No. 1 represented by the following structural formula. An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that it was replaced with 1-4.

(Example 7)
-Production of electrophotographic photoreceptor-
In Example 1, Exemplified Compound No. 1 was used as the charge transport agent in the preparation of the charge transport layer coating solution. 1-1 is exemplified compound No. 1 represented by the following structural formula. An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that 1-5 was used.

(Example 8)
-Production of electrophotographic photoreceptor-
In Example 1, in the preparation of the charge transport layer coating solution, the polycarbonate copolymer No. 1 represented by the above chemical formula as the binder resin was used. 2-2 and Exemplified Compound Nos. Represented by the above structural formulas as charge transporting agents. 1-1, 2,6-di-tert-butyl-4-methylphenol as an antioxidant, and 2- (2-hydroxy-5-methylphenyl) benzotriazole (Tinvin-P, Geigy) as an ultraviolet absorber Made by mass ratio (polycarbonate copolymer No. 2-2: Exemplified Compound No. 1-1: 2,6-di-tert-butyl-4-methylphenol: Tinuvin-P) is 100: 40: An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that mixing was performed so that the ratio was 1.5: 1.5.

Example 9
-Production of electrophotographic photoreceptor-
In Example 1, in the preparation of the charge transport layer coating solution, the polycarbonate copolymer No. 1 represented by the above chemical formula as the binder resin was used. 2-2 and Exemplified Compound Nos. Represented by the above structural formulas as charge transporting agents. 1-1, 2,6-di-tert-butyl-4-methylphenol as an antioxidant, and 2- (2-hydroxy-5-methylphenyl) benzotriazole (Tinvin-P, Geigy) as an ultraviolet absorber Made by mass ratio (polycarbonate copolymer No. 2-2: Exemplified Compound No. 1-1: 2,6-di-tert-butyl-4-methylphenol: Tinuvin-P) is 100: 80: An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that mixing was performed so that the ratio was 1.5: 1.5.

(Example 10)
-Production of electrophotographic photoreceptor-
In Example 1, the same procedure as in Example 1 was conducted except that the oxytitanium phthalocyanine powder obtained in Synthesis Example 1 was replaced with the oxytitanium phthalocyanine powder obtained in Synthesis Example 2 in the preparation of the charge generation layer coating solution. Thus, an electrophotographic photosensitive member was produced.

(Example 11)
-Production of electrophotographic photoreceptor-
In Example 1, except that the oxytitanium phthalocyanine powder obtained in Synthesis Example 1 was replaced with the α-type oxytitanium phthalocyanine powder obtained in Synthesis Example 3 in the preparation of the charge generation layer coating solution. Similarly, an electrophotographic photosensitive member was produced.

(Example 12)
-Production of electrophotographic photoreceptor-
In Example 1, except that the oxytitanium phthalocyanine powder obtained in Synthesis Example 1 was replaced with the β-type oxytitanium phthalocyanine powder obtained in Synthesis Example 4 in the preparation of the charge generation layer coating solution. Similarly, an electrophotographic photosensitive member was produced.

(Comparative Example 1)
-Production of electrophotographic photoreceptor-
In Example 1, in the preparation of the charge transport layer coating solution, Exemplified Compound No. 1 represented by the above structural formula as a charge transport agent was used. An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that 1-1 was replaced with a charge transfer agent represented by the following structural formula (A).

(Comparative Example 2)
-Production of electrophotographic photoreceptor-
In Example 1, in the preparation of the charge transport layer coating solution, Exemplified Compound No. 1 represented by the above structural formula as a charge transport agent was used. An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that 1-1 was replaced with a charge transfer agent represented by the following structural formula (B).

(Comparative Example 3)
-Production of electrophotographic photoreceptor-
In Example 1, in the preparation of the charge transport layer coating solution, Exemplified Compound No. 1 represented by the above structural formula as a charge transport agent was used. An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that 1-1 was replaced with a charge transfer agent represented by the following structural formula (C).

(Comparative Example 4)
-Production of electrophotographic photoreceptor-
In Example 1, in the preparation of the charge transport layer coating solution, the polycarbonate copolymer No. 1 represented by the above chemical formula as the binder resin was used. 2-2 is replaced with Z-type polycarbonate (Panlite TS2050, manufactured by Teijin Chemicals Ltd.), Z-type polycarbonate (Panlite TS2050), and exemplified compound No. 2 represented by the above structural formula as a charge transport agent. 1-1, 2,6-di-tert-butyl-4-methylphenol as an antioxidant, and 2- (2-hydroxy-5-methylphenyl) benzotriazole (Tinvin-P, Geigy) as an ultraviolet absorber Product) and mass ratio (Panlite TS2050: Exemplified Compound No. 1-1: 2,6-di-tert-butyl-4-methylphenol: Tinuvin-P) at 100: 40: 1.5: 1. An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the mixture was mixed so as to be 5.

(Comparative Example 5)
-Production of electrophotographic photoreceptor-
In Example 1, in the preparation of the charge transport layer coating solution, the polycarbonate copolymer No. 1 represented by the above chemical formula as the binder resin was used. 2-2 is replaced with Z-type polycarbonate (Panlite TS2050, manufactured by Teijin Chemicals Ltd.), Z-type polycarbonate (Panlite TS2050), and exemplified compound No. 2 represented by the above structural formula as a charge transport agent. 1-1, 2,6-di-tert-butyl-4-methylphenol as an antioxidant, and 2- (2-hydroxy-5-methylphenyl) benzotriazole (Tinvin-P, Geigy) as an ultraviolet absorber Product) and mass ratio (Panlite TS2050: Exemplified Compound No. 1-1: 2,6-di-tert-butyl-4-methylphenol: Tinuvin-P) at 100: 80: 1.5: 1. An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the mixture was mixed so as to be 5.

(Comparative Example 6)
-Production of electrophotographic photoreceptor-
In Example 1, in the preparation of the charge transport layer coating solution, the polycarbonate copolymer No. 1 represented by the above chemical formula as the binder resin was used. 2-2 is a polycarbonate copolymer No. 2 represented by the following chemical formula. An electrophotographic photoreceptor was produced in the same manner as in Example 1 except that A (copolymerization molar ratio (m: n) = 30: 70) was used.

(Comparative Example 7)
-Production of electrophotographic photoreceptor-
In Example 1, in the preparation of the charge transport layer coating solution, the polycarbonate copolymer No. 1 represented by the above chemical formula as the binder resin was used. 2-2 is a polycarbonate copolymer No. 2 represented by the following chemical formula. An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that B (copolymerization molar ratio (m: n) = 55: 45) was used.

(Comparative Example 8)
In Example 1, in the preparation of the charge transport layer coating solution, the polycarbonate copolymer No. 1 represented by the above chemical formula as the binder resin was used. 2-2 and Exemplified Compound Nos. Represented by the above structural formulas as charge transporting agents. 1-1, 2,6-di-tert-butyl-4-methylphenol as an antioxidant, and 2- (2-hydroxy-5-methylphenyl) benzotriazole (Tinvin-P, Geigy) as an ultraviolet absorber Made by mass ratio (polycarbonate copolymer No. 2-2: Exemplified Compound No. 1-1: 2,6-di-tert-butyl-4-methylphenol: Tinuvin-P) is 100: 90: An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that mixing was performed so that the ratio was 1.5: 1.5.

  Next, various characteristics were measured and evaluated for each electrophotographic photosensitive member produced in Examples and Comparative Examples as follows. The results are shown in Table 1.

<Elastic power and universal hardness>
For each electrophotographic photosensitive member produced in the examples and comparative examples, an indentation depth of 1 μm from the surface of the charge transport layer using the elastic power measurement device (Fischer Scope, Fischer Instruments H-100) under the following conditions. The elastic power and universal hardness of the charge transport layer were measured. The universal hardness of the charge transport layer represents the displacement of the indenter at the maximum load as a hardness value, and the elastic power of the charge transport layer was calculated from the graph of the load-unload test.
〔Measurement condition〕
・ Measurement environment: Temperature 22 ℃, Humidity 55% RH
・ Measurement device: H-100 manufactured by Fischerscope
・ Vickers square pyramid diamond indenter ・ Measurement mode: dF / dt = const
・ Set load: 9.8mN
・ Loading / unloading time: 30 sec each
・ Creep time: 5 sec

<Evaluation of initial electrical characteristics and potential change after fatigue>
Using an electrophotographic photoreceptor evaluation apparatus (manufactured by Yamanashi Electronics Co., Ltd.), each electrophotographic photoreceptor produced in the examples and comparative examples was subjected to an environment (N / N) of a temperature of 23 ° C. and a humidity of 50% RH. The surface potential (V0) of the photoreceptor when a discharge current of 25 μA was applied to the photoreceptor by the scorotron method was measured at the initial stage and after 10,000 cycles of fatigue. Thereafter, the discharge current is adjusted so that the surface potential becomes −700 V, and the exposure energy amount [half exposure energy amount (E) when the surface potential irradiated with a semiconductor laser having a wavelength of 780 nm is attenuated to ½ (−350 V). _1/2 ); Sensitivity] was measured. Further, the surface potential of the photoreceptor when irradiated with an exposure energy of 1.0 μJ / cm ^{2 was} defined as a residual potential (VL), and was measured at the initial stage and after 10,000 cycles of fatigue. These measurement results are measurement results at a development-exposure interval of 100 ms.
(Evaluation index)
・ V0 is good at 700V ± 50V both in the initial stage and after 1,000 cycles fatigue test. Outside this range, a change in image density is observed.
-The upper limit of VL is about 100 V, and the half-exposure energy (E _1/2 ) is 0.13 μJ / cm ² or more, resulting in a decrease in image density.
・ V0 drop causes image noise at Δ50V or more.

<Print durability>
Continuously 1,000 using a color laser printer (IPSiO C-220, manufactured by Ricoh Co., Ltd .; erase-less type image forming apparatus not equipped with static eliminating means) equipped with the electrophotographic photoreceptors of the produced examples and comparative examples. Using a Fischer scope MMS (manufactured by Fischer Instruments Co., Ltd.), the change in the thickness of the photosensitive layer before and after the printing test was measured for a total of 32 points, 16 points in the longitudinal direction of the photoconductor and 2 points in the circumferential direction. The printing durability was evaluated based on the change in thickness (Δ μm) before and after the printing test. A thickness change (Δ μm) of 0.42 μm or less was accepted.

<Cleanability>
Using a color laser printer (manufactured by Ricoh Co., Ltd., IPSiO C-220; erase-less type image forming apparatus not equipped with static eliminating means) equipped with the electrophotographic photoreceptors of the produced examples and comparative examples. 10,000 sheets were printed with a test pattern, solid black was printed every 1,000 sheets, and the cleaning property was evaluated according to the following criteria from the state of white spots appearing in a black image. The evaluation environment was 23 ° C. and 50% RH. Here, the “white spot” means a state in which the toner adheres to the surface of the photoreceptor due to poor cleaning, and the toner is not placed on that portion.
〔Evaluation criteria〕
◯: No white spots in the solid black image Δ: No white spots occur in the solid black image, but toner fixation is observed on the electrophotographic photosensitive member ×: White spots occur in the solid black image

<Solubility>
Regarding the charge transport layer coating solutions prepared in Examples and Comparative Examples, the solubility was determined by visual observation according to the following criteria depending on whether the solution was a transparent solution or a cloudy solution.
〔Evaluation criteria〕
○: Transparent state in which the binder resin and charge transport agent are uniformly dissolved in the charge transport layer coating solution ×: The binder resin and charge transport agent in the charge transport layer coating solution are not uniformly dissolved and are in an opaque state or a solid resin Remaining state

From the results in Table 1, it was found that the electrophotographic photoreceptors of Examples 1 to 10 were excellent in terms of initial electrical characteristics, potential change after fatigue, printing durability, cleaning properties, and solubility.
In Examples 11 to 12, the printing durability, the cleaning property, and the solubility are good. However, since a specific crystal type charge generator is not used, slightly sufficient photoreceptor characteristics are not obtained. I understood.
It was found that the electrophotographic photoreceptors of Comparative Examples 1 to 3 did not have sufficient electrical characteristics because the charge transport agent represented by the general formula (1) was not used in the charge transport layer.
Since the photoconductors of Comparative Examples 4 to 5 use a binder resin other than the polycarbonate copolymer represented by the above general formula (2) for the charge transport layer, either the universal hardness or the elastic work rate is present. Since it is out of the scope of the invention, sufficient printing durability and cleaning properties cannot be obtained.
In the photoreceptor of Comparative Example 6, the copolymerization molar ratio of the polycarbonate copolymer represented by the above general formula (2), which is the binder resin of the charge transport layer, is outside the range of the present invention. It was found that printing properties and cleaning properties were good, but printing durability was poor.
In the photoreceptor of Comparative Example 7, the copolymerization molar ratio of the polycarbonate copolymer represented by the general formula (2), which is the binder resin of the charge transport layer, is outside the range of the present invention. It was found that the printability was good, but the cleanability and solubility were poor.
In Comparative Example 8, since the universal hardness was outside the range of the present invention, it was found that the sensitivity, the cleaning property and the solubility were good, but the printing durability was inferior.

  The electrophotographic photosensitive member of the present invention can cope with the process of reducing the diameter of the photosensitive member and the speed of the peripheral speed accompanying the downsizing and speeding up of the image forming apparatus, and is excellent in durability. It is widely used in direct digital plate-making machines, full-color copiers using direct or indirect electrophotographic multicolor image development systems, full-color laser printers, full-color plain paper fax machines, and the like.

DESCRIPTION OF SYMBOLS 11 Electrophotographic photosensitive member 12 Charging means 13 Power supply 14 Exposure means 15 Developing means 16 Primary transfer means (transfer belt)
17 Primary transfer roller 18 Constant voltage power supply 19 Cleaning means 20 Secondary transfer means (secondary transfer roller)
21 Static elimination means 22 Fixing means (fixing roller)
23 Recording media (paper)

Claims (5)

An electrophotographic photoreceptor having a support and a photosensitive layer comprising a charge generation layer and a charge transport layer on the support,
The charge transport layer contains a binder resin and a compound represented by the following general formula (1),
The binder resin is a polycarbonate copolymer represented by the following general formula (2):
Under an environment of a temperature of 22 ° C. and a relative humidity of 55% RH, using a Vickers square pyramid diamond indenter, a set load is 9.8 mN, and the elastic work modulus of the charge transport layer is 38% at an indentation depth of 1 μm from the surface of the charge transport layer. An electrophotographic photosensitive member characterized by having a hardness of ˜48% and a universal hardness of 180 N / m ^{2 to} 200 N / m ² .
However, in said general formula (1), R < ¹ > -R < ⁴ > may mutually be the same, may differ, and a C1-C6 alkyl which may have a hydrogen atom and a substituent. Represents any of a group and an alkoxyl group having 1 to 6 carbon atoms which may have a substituent.
However, in said general formula (2), copolymerization molar ratio (m: n) is 35: 65-50: 50.   The charge generation layer contains a charge generation agent, the charge generation agent is oxytitanium phthalocyanine, and the oxytitanium phthalocyanine is at least 27 as a diffraction peak (± 0.2) of an X-ray diffraction Bragg angle 2θ with respect to CuKα rays. The electrophotographic photosensitive member according to claim 1, wherein the electrophotographic photosensitive member has a maximum diffraction angle at 2 ° and further has main peaks at 9.7 °, 14.2 °, 18.0 °, and 24.2 °.   The charge generation layer contains a charge generation agent, the charge generation agent is oxytitanium phthalocyanine, and the oxytitanium phthalocyanine is at least 27 as a diffraction peak (± 0.2 °) with an X-ray diffraction Bragg angle 2θ with respect to CuKα rays. It has a maximum diffraction peak at 2 °, and further main peaks at 9.4 °, 9.6 °, and 24.0 °, and the peak at 7.3 ° as the lowest diffraction peak. The electrophotographic photosensitive member according to claim 1, having no peak in the range of 7.4 ° or more and less than 9.4 °, and further having no peak at 26.3 °. An electrophotographic photosensitive member; a charging unit that charges the surface of the electrophotographic photosensitive member; an exposing unit that exposes the surface of the charged electrophotographic photosensitive member to form an electrostatic latent image; and An image forming apparatus comprising: a developing unit that develops a visible image by using a developing unit; and a transfer unit that transfers the visible image to a recording medium.
The image forming apparatus according to claim 1, wherein the electrophotographic photosensitive member is the electrophotographic photosensitive member according to claim 1.   The image forming apparatus according to claim 4, wherein the image forming apparatus is an eraseless type image forming apparatus that does not have a charge eliminating means for discharging the surface of the electrophotographic photosensitive member.