JP5371450B2 - Electrophotographic photoreceptor and image forming apparatus having the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photoreceptor suitable for exposure to light at a short wavelength of a blue semiconductor laser, having high resolution and excellent mechanical and electric durability even in long-term repetitive use, and having high durability preventing generation of abnormal images; and to provide an image forming apparatus equipped with the photoreceptor. <P>SOLUTION: The electrophotographic photoreceptor has a photosensitive layer, in which a charge generating layer and a charge transport layer are stacked in this order, on a conductive support, wherein the charge generating layer contains oxotitanylphthalocyanine as a charge generating material and a predetermined enamine-based compound as an additive and has photosensitive characteristics to light at the wavelength from 360 to 420 nm. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to an electrophotographic photosensitive member (hereinafter also referred to as “photosensitive member”) that can be used for electrophotographic image formation and can be exposed to light having a short wavelength, and an image forming apparatus including the same.

  An electrophotographic image forming apparatus (also referred to as an “electrophotographic apparatus”) that forms an image using electrophotographic technology plays a part in high-speed information processing system equipment, and its progress has been remarkable in recent years. Among these system devices, the electrophotographic method using light as a recording probe, together with the qualitative improvement of the light source itself, significantly improves the quality and reliability of print output. Therefore, these technologies are being developed not only for normal printer output but also for copiers, and their importance is increasing, and it is expected that demand will continue to grow.

  In recent years, printers and copiers are expected to have high image quality including colorization. The directionality to achieve this is as follows: “reducing the diameter of the light source (exposure beam) and increasing the resolution of the latent image / development caused thereby” and “photoreceptor capable of stably providing the above. Stabilization ”.

Shortening the wavelength of the light source is effective for reducing the diameter of the exposure beam, which is the former requirement. For example, when a short-wavelength laser having a central oscillation wavelength of about half that of a conventional near-infrared laser is used as a writing light source, a laser beam on the photosensitive member is expressed by the following equation (1). In theory, the spot diameter can be considerably reduced.
d∝ (π / 4) (λf / D) (1)
(Where d is the spot diameter on the photoreceptor, λ is the wavelength of the laser light, f is the focal length of the fθ lens, and D is the lens diameter)
Therefore, they are very advantageous for improving the latent image writing density, that is, the resolution.

However, since such a short wavelength laser is shorter than the center oscillation wavelength of a conventional exposure member, several problems occur in order to operate the photoconductor stably.
The first problem relates to the stability of the photoreceptor. That is, since the conventional writing wavelength is longer than 450 nm, writing was possible from the photosensitive member surface side even if the charge transporting material of the charge transporting layer was yellow. However, in the short wavelength laser, when the charge transporting material blocks the writing light, not only the photosensitivity is lowered, but also the deterioration of the charge transporting material itself is promoted, and the function of the photoreceptor itself is lowered.
Therefore, when a short wavelength laser is used, an optically colorless material should be used as the charge transport material, and it is necessary to develop such a charge transport material. In this regard, a material that is nearly colorless and transparent after film formation is selected as a molecular structure from the charge transport materials that have been developed so far.

  The second problem relates to the stability of the charge generating material. That is, compared with light absorption for a near-infrared laser and the accompanying charge generation process, it differs greatly in terms of interaction with a substance for light with a short wavelength. In other words, even when using the same charge generation material, the energy of light at short wavelengths is clearly greater than that of current near-infrared lasers, and the excess energy during the process leading to the generation of carriers by light. In addition, a secondary effect is considered. Although the detailed process is not clear, it is cited as a problem for stability as a photoreceptor.

  In the past, efforts to increase the resolution using a short wavelength laser began in Japanese Patent Application Laid-Open No. 9-240051 (Patent Document 1), and combinations with various charge generation materials, for example, Japanese Patent Application Laid-Open No. 2000-47408 (Patent Document 2). ) And Japanese Patent Laid-Open No. 2000-105479 (Patent Document 3), etc., but both “realization of high resolution” and “ensurement of stability as a photoreceptor” have not been realized.

Japanese Patent Laid-Open No. 9-240051 JP 2000-47408 A JP 2000-105479 A

  The present invention is suitable for exposure to light of a short wavelength of a blue semiconductor laser, has high resolution, is excellent in mechanical / electric durability even for repeated use over a long period of time, and does not generate abnormal images. It is an object of the present invention to provide a photosensitive member and an image forming apparatus including the photosensitive member.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors are originally known as a charge transport material having high mobility as an additive in addition to oxotitanyl phthalocyanine as a charge generation material. The inventors have found that the above problems can be solved by including an enamine compound (for example, see JP-A No. 2004-151666) in the charge generation layer, and have completed the present invention.

Thus, according to the present invention, at least a photosensitive layer in which a charge generation layer and a charge transport layer are laminated in this order is laminated on a conductive support.
The charge generation layer comprises oxotitanyl phthalocyanine as a charge generation material and general formula (I) as an additive:

[Where:
Ar ¹ and Ar ² are the same or different and are an aryl group which may have a substituent or a monovalent heterocyclic residue which may have a substituent, and Ar ¹ and Ar ² bind to them May be bonded to each other through a group of atoms or atomic groups to form a ring structure;
Ar ³ is an aryl group that may have a substituent, a cycloalkyl group that may have a substituent, an alkyl group that may have a substituent, or a monovalent complex that may have a substituent. A ring residue;
Ar ⁴ and Ar ⁵ are the same or different and each represents a hydrogen atom, an aryl group which may have a substituent, an alkyl group which may have a substituent, or a monovalent heterocyclic ring which may have a substituent A residue, Ar ⁴ and Ar ⁵ are not both hydrogen atoms, but may be bonded to each other via an atom or atomic group bonded to them to form a ring structure;

a represents an alkyl group which may have a substituent, an alkoxy group which may have a substituent, a dialkylamino group which may have a substituent, an aryl group which may have a substituent, a halogen atom; Or a hydrogen atom;
m is an integer of 1 to 6, and when m is 2 or more, a plurality of a may be the same or different and are bonded to each other via an atom or an atomic group bonded thereto to form a ring structure. Well;
R ¹ is a hydrogen atom, a halogen atom or an alkyl group which may have a substituent;
R ² , R ³ and R ⁴ are the same or different and are a hydrogen atom, an alkyl group which may have a substituent, an aryl group which may have a substituent, or a monovalent which may have a substituent. A heterocyclic residue of
n is an integer of 0 to 3, and when n is 2 or 3, a plurality of R ² and R ³ may be the same or different, and when n is 0, Ar ³ has a substituent. May be a monovalent heterocyclic residue]
And a photoconductor characterized by having photosensitivity to light having a wavelength of 360 to 420 nm.

According to the present invention, the photosensitive member is formed by the exposure, the charging unit for charging the photosensitive member, the exposure unit for exposing the charged photosensitive member to form an electrostatic latent image, and the exposure. Developing means for developing the electrostatic latent image to form a toner image, transfer means for transferring the toner image formed by development onto a recording medium, and fixing the transferred toner image on the recording material And at least a fixing unit that forms an image, a cleaning unit that removes and collects toner remaining on the photoconductor, and a neutralizing unit that neutralizes surface charge remaining on the photoconductor.
An image forming apparatus is provided in which the exposure unit includes an exposure light source having a central oscillation wavelength at a wavelength of 360 to 420 nm.

  According to the present invention, it is suitable for exposure by light of a short wavelength of a blue semiconductor laser, has high resolution, excellent mechanical / electric durability even for repeated use over a long period of time, and does not generate abnormal images. A durable photoconductor and an image forming apparatus including the same can be provided.

It is a figure which shows the visible-ultraviolet absorption spectrum of the enamine type compound (exemplary compound 1) of this invention. FIG. 3 is a schematic cross-sectional view illustrating a configuration of a main part of the photoreceptor of the present invention. It is a figure which shows the X-ray-diffraction spectrum of the oxo titanyl phthalocyanine crystal | crystallization suitable for this invention. 1 is a schematic side view illustrating a configuration of a main part of an image forming apparatus of the present invention.

  The photoreceptor of the present invention comprises at least a photosensitive layer in which a charge generation layer and a charge transport layer are laminated in this order on a conductive support, and the charge generation layer comprises oxo as a charge generation material. It contains titanyl phthalocyanine and an enamine compound represented by the general formula (I) as an additive, and has photosensitivity to light having a wavelength of 360 to 420 nm.

In the photoconductor of the present invention, by allowing the oxotitanyl phthalocyanine and the enamine compound represented by the general formula (I) to coexist in the charge generation layer, for the exposure of a short wavelength light source (360 to 420 nm), It is considered that stable high sensitivity is realized by such a process.
That is, charges are excited to a higher energy level by light absorption of oxotitanylphthalocyanine by the above short wavelength light source, and then become free carriers through the lowest excitation level. During this time, carriers are trapped as a secondary trap. Captures the sensitivity destabilization. The coexistence of the enamine compound here facilitates charge separation, and it is considered that holes are injected from the charge generation layer into the charge transport layer without being trapped by the trap.

Further, as described above, enamine compounds are originally known as high mobility charge transport materials, but unlike other charge transport materials, they have an absorption band in a short wavelength region (see FIG. 1). It is considered that it also contributes to the improvement of the sensitivity of the photoreceptor by functioning as a charge generating material that absorbs light in a short wavelength region and generates charges. That is, in the wavelength region of 500 nm or more, the enamine compound has an absorbance of 0% (transmittance of 100%). Therefore, exposure with a long wavelength light source does not absorb light even if the enamine compound coexists in the charge generation layer. Therefore, the photoreceptor of the present invention is suitable for short wavelength exposure with a wavelength of 360 to 420 nm.
FIG. 1 is a view showing a visible-ultraviolet absorption spectrum of an enamine compound of the present invention (exemplary compound 1 described later).
This absorption spectrum is a result obtained by dissolving an enamine compound in tetrahydrofuran (THF) at a concentration of 0.01% and measuring it with a spectrophotometer (manufactured by Hitachi, Ltd.).

The configuration of the photoreceptor of the present invention will be specifically described with reference to FIG. 2, but the present invention is not limited to the modes described below.
FIG. 2 is a schematic cross-sectional view showing the structure of the main part of the photoreceptor of the present invention. On the conductive substrate 1, the charge generation layer 3 containing the undercoat layer 6 and the charge generation material 2 and the charge transport material 4. A photosensitive layer (laminated photosensitive layer) 21 in which the charge transport layer 5 containing s is laminated in this order is laminated. In the figure, 7 indicates a binder resin (binder resin).
The photoreceptor of the present invention may have a reverse two-layered laminated structure in which a charge generating layer and a charge transporting layer are formed in reverse order, but the laminated type is preferred.

[Conductive support (conductive substrate) 1]
The conductive support serves as an electrode for the photoreceptor and also functions as a support member for other layers.
The constituent material of the conductive support is not particularly limited as long as it is a material used in this field.
Specifically, metals and alloy materials such as aluminum, aluminum alloy, copper, brass, zinc, nickel, stainless steel, chromium, molybdenum, vanadium, indium, titanium, gold, platinum: polyethylene terephthalate, polyamide, polyester, polyoxy Polymer material such as methylene, polystyrene, cellulose, polylactic acid, hard paper, glass substrate laminated with metal foil, metal material or alloy material deposited, conductive polymer, tin oxide, oxidation Examples thereof include those obtained by depositing or applying a layer of a conductive compound such as indium or carbon black.

The shape of the conductive support is not limited to a sheet shape as shown in FIG. 2 and a cylindrical shape described later, and may be a columnar shape, an endless belt (seamless belt) shape, or the like.
When each layer is applied and formed on a conductive support by a dip coating method as in an embodiment described later, the shape is preferably cylindrical.
If necessary, the surface of the conductive support is subjected to irregular reflection treatment such as anodizing film treatment, surface treatment with chemicals, hot water, coloring treatment, and surface roughening within a range that does not affect the image quality. May be given.

  The irregular reflection treatment is particularly effective when the photoreceptor according to the present invention is used in an electrophotographic process using a laser as an exposure light source. That is, in the electrophotographic process using a laser as an exposure light source, the wavelength of the laser beam is uniform, so the laser beam reflected on the surface of the photoconductor and the laser beam reflected inside the photoconductor cause interference, Interference fringes due to this interference may appear in the image and cause image defects. Therefore, by performing irregular reflection processing on the surface of the conductive support, it is possible to prevent image defects due to interference of laser light having a uniform wavelength.

[Undercoat layer (intermediate layer) 6]
The photoreceptor of the present invention may have an undercoat layer between the conductive support and the photosensitive layer.
The undercoat layer prevents injection of charges from the conductive support to the photosensitive layer, reduces the degree of irregularities that are defects on the surface of the conductive support, and makes the surface uniform, improving the film formability of the photosensitive layer. In addition to having the function of improving the adhesion (adhesiveness) between the conductive support and the photosensitive layer, it also has the functions of preventing deterioration of charging property during repeated use and improving charging characteristics in a low temperature / low humidity environment. .

  For the undercoat layer, for example, a resin material is dissolved in a suitable solvent to prepare a coating solution for the undercoat layer, this coating solution is applied to the surface of the conductive support 1, and the organic solvent is removed by drying. Can be formed.

  Examples of the resin material include known resins, specifically, polyamide, copolymer nylon, polyvinyl alcohol, polyurethane, polyester, epoxy resin, phenol resin, casein, cellulose, gelatin, and the like, one or two of these. The above can be used. Among these resins, polyamide is preferable, and alcohol-soluble nylon is particularly preferable.

  Examples of the solvent for dissolving the resin material include water, alcohols such as methanol, ethanol and butanol, glymes such as methyl carbitol and butyl carbitol, and mixed solvents obtained by mixing two or more of these solvents. . The mixed solvent includes a mixed solvent of water and alcohols, a mixed solvent of two or more alcohols, a mixed solvent of acetone and dioxolane and alcohols, a chlorinated solvent such as dichloroethane, chloroform and trichloroethane, and alcohols. Or a mixed solvent thereof.

The undercoat layer may contain metal oxide fine particles.
The metal oxide fine particles can easily adjust the volume resistance value of the undercoat layer, can further suppress the injection of charges into the laminated photosensitive layer, and can maintain the electrical characteristics of the photoreceptor in various environments.
Examples of the metal oxide fine particles include zinc oxide, titanium oxide, tin oxide, indium oxide, silica, and antimony oxide.
The metal oxide fine particles are preferably contained in the undercoat layer in an amount of 30 to 95% by weight. More preferably, it is 40 to 90% by weight.
The undercoat layer coating liquid to which the metal oxide fine particles are added may be dispersed in advance using a general pulverizer such as a ball mill, a dyno mill, or an ultrasonic disperser.

The method of applying an undercoat layer coating solution may be selected the best method in consideration of the physical properties and productivity of the coating solution, the concrete, roll coating, spray coating, blade coating, ring coating, Examples include dip coating.
Among these coating methods, the dip coating method is a method of forming a layer on the surface of the substrate by immersing the substrate in a coating tank filled with a coating solution and then pulling it up at a constant rate or a rate that changes sequentially. Yes, it is relatively simple, and it excels in productivity and cost. Therefore, the dip coating method is often used when manufacturing a photoreceptor. In addition, in order to stabilize the dispersibility of a coating liquid, the apparatus used for the dip coating method may be provided with a coating liquid dispersing apparatus represented by an ultrasonic generator.

The solvent in the coating film may be removed by natural drying, or the solvent in the coating film may be forcibly removed by heating. The temperature in such a drying step is a temperature at which the organic solvent used can be removed. If it is, it will not specifically limit, However, 40-130 degreeC is suitable, and 80-130 degreeC is especially preferable.
If the drying temperature is less than 40 ° C., the drying time may be long. On the other hand, if the drying temperature exceeds 140 ° C., the electrical characteristics during repeated use of the photoreceptor may deteriorate and the resulting image may deteriorate.
The drying time is suitably about 10 minutes to 2 hours.

Although the film thickness of an undercoat layer is not specifically limited, 0.01-5 micrometers is preferable and 0.1-2 micrometers is especially preferable.
If the thickness of the undercoat layer is less than 0.01 μm, the undercoat layer does not substantially function, and it is impossible to obtain a uniform surface property by covering defects of the conductive support. There is a possibility that charge injection into the photosensitive layer may not be prevented, and when the thickness of the undercoat layer exceeds 5 μm, it is difficult to form a uniform undercoat layer, and the sensitivity of the photoreceptor may also be reduced. There is.

[Charge generation layer 3]
The charge generation layer 3 contains oxo titanyl phthalocyanine as a charge generation material and an enamine compound represented by the general formula (I), and optionally contains a binder resin.

The oxo titanyl phthalocyanine of the present invention has the formula (A):

(Wherein X ¹ , X ² , X ³ and X ⁴ are the same or different and are a halogen atom, an alkyl group or an alkoxy group, and r, s, y and z are the same or different and represent 0-4. Is an integer)
Indicated by

Examples of the halogen atom of X ¹ , X ² , X ³ and X ^{4 in} the formula (A) include fluorine, chlorine, bromine and iodine atoms.
Examples of the alkyl group represented by X ¹ , X ² , X ³ and X ⁴ include alkyl groups having 1 to 4 carbon atoms such as methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group and t-butyl group. Is mentioned.
Examples of the alkoxy group for X ¹ , X ² , X ³ and X ⁴ include alkoxy having 1 to 4 carbon atoms such as methoxy group, ethoxy group, propoxy group, isopropoxy group, butoxy group, isobutoxy group and t-butoxy group. Groups.

  The oxotitanium phthalocyanine compound represented by the formula (A) is produced by a known production method such as, for example, the method described in Phthalcocyanine Compounds by Moser, Frank H and Arthur L. Thomas, Reinhold Publishing Corp., New York, 1963. can do.

  For example, among the oxotitanium phthalocyanine compounds represented by the formula (A), in the case of an unsubstituted oxotitanium phthalocyanine in which r, s, y, and z are 0, are phthalonitrile and titanium tetrachloride heated and melted? Alternatively, it can be obtained by synthesizing dichlorotitanium phthalocyanine by heating in a suitable solvent such as α-chloronaphthalene and then hydrolyzing with base or water.

  Alternatively, oxotitanium phthalocyanine can also be produced by reacting isoindoline with titanium tetraalkoxide such as tetrabutoxytitanium in a suitable solvent such as N-methylpyrrolidone.

  The oxotitanium phthalocyanine crystal is obtained by pulverizing (milling) the oxotitanium phthalocyanine obtained by hydrolysis with a mechanical strain in an organic solvent such as methyl ethyl ketone, or stirring for a sufficient time. The former method is preferable.

The oxotitanium phthalocyanine crystal can be obtained by treating oxotitanium phthalocyanine with an organic solvent immiscible with water such as dichloroethane in the presence of water.
Specifically, there are a method of treating oxotitanium phthalocyanine swollen with water with an organic solvent, a method of adding water to an organic solvent without performing the swelling treatment, and introducing oxotitanium phthalocyanine into the solvent, etc. Although it is mentioned, it is not limited to these.

  Examples of the method for swelling oxotitanium phthalocyanine with water include, for example, a method in which oxotitanium phthalocyanine is dissolved in sulfuric acid and precipitated in water to form a wet paste, and stirring / dispersing devices such as homomixers, paint mixers, ball mills, sand mills, etc. Is used to swell oxotitanium phthalocyanine with water to form a wet paste, but is not limited to these methods.

The oxo titanyl phthalocyanine of the present invention exhibits a maximum diffraction peak at a Bragg angle (2θ ± 0.2 °) of 9.4 ° or 9.7 ° in an X-ray diffraction spectrum using CuKα rays (1.541１．５). Especially preferred are oxotitanyl phthalocyanine crystals having a specific crystal form with diffraction peaks at least at 7.3 °, 9.4 °, 9.7 ° and 27.3 ° (see FIG. 3).
A photoreceptor containing an oxotitanyl phthalocyanine crystal having such a specific crystal type can provide a high-sensitivity and high-quality image, has excellent potential stability against repeated use, and is an electrophotographic image using reversal development. Generation of ground fog and the like in the process can be effectively suppressed. With regard to this electrical stability, not only when irradiated with a near-infrared laser (780 nm), but also with a short wavelength light source, for example, when using a GaN-based semiconductor laser having a central oscillation wavelength at 405 nm, for example, Provide the desired electrical properties.

Oxo titanyl phthalocyanine may be used in combination with other charge generation materials as long as the effects of the present invention are not impaired. By using together with other charge generation materials, the light attenuation curve can be adjusted arbitrarily and easily, and the degree of freedom is widened and advantageous in designing the image forming process.
Examples of such charge generation materials include azo pigments (monoazo pigments, bisazo pigments, trisazo pigments, etc.), indigo pigments (indigo, thioindigo, etc.), perylene pigments (peryleneimide, perylene acid anhydride, etc.). ), Polycyclic quinone pigments (anthraquinone, pyrenequinone, etc.), phthalocyanine pigments (α-type, β-type, Y-type and other crystalline oxotitanium phthalocyanine crystals, metal phthalocyanines, metal-free phthalocyanines, halogenated metal-free phthalocyanines ), Squarylium dyes, pyrylium salts, thiopyrylium salts, triphenylmethane dyes (methyl violet, crystal violet, knight blue, victoria blue, etc.) acridine dyes (erythrosin, rhodamine B, rhodamine 3R, acridi) Orange, frappeosin, etc.), thiazine dyes (methylene blue, methylene green, etc.), oxazine dyes (capri blue, meldra blue, etc.), bisbenzimidazole dyes, quinacridone dyes, quinoline dyes, lake dyes, azo lakes Organic pigments or dyes (organic photoconductive materials) such as selenium dyes, dioxazine dyes, azurenium dyes, triallylmethane dyes, xanthene dyes, cyanine dyes, and inorganic materials such as selenium and amorphous silicon (Inorganic photoconductive material).
As the azo pigment, an azo pigment having a carbazole skeleton, a styryl stilbene skeleton, a triphenylamine skeleton, a dibenzothiophene skeleton, an oxadiazole skeleton, a fluorenone skeleton, a bis stilbene skeleton, a distyryl oxadiazole skeleton or a distyryl carbazole skeleton Is mentioned.

The enamine compound of the present invention is represented by the general formula (I).
Among the enamine compounds of general formula (I), sub-formula (II):

[Where:
b, c and d are the same or different and each has an alkyl group which may have a substituent, an alkoxy group which may have a substituent, a dialkylamino group which may have a substituent, or a substituent. An aryl group, a halogen atom or a hydrogen atom, which may be
i, j and k are the same or different and are integers of 1 to 5, and when i, k or j is 2 or more, the corresponding plural b, c or d may be the same or different, and May be bonded to each other via an atom or atomic group bonded to the ring to form a ring structure;
Ar ⁴ , Ar ⁵ , a and m have the same meaning as in general formula (1)]
The compound shown by is especially preferable.

The substituents in general formula (I) and sub-formula (II) will be described.
Examples of the aryl group that may have a substituent of Ar ¹ and Ar ² include, for example, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a dialkylamino group having 2 to 6 carbon atoms, and a halogen atom. And an aryl group which may be substituted with.
Specific examples include a phenyl group, a p-tolyl group, a 4-methoxyphenyl group, a 4-chlorophenyl group, a 4-fluorophenyl group, a 1-naphthyl group, and a 2-naphthyl group.
Examples of the monovalent heterocyclic residue which may have a substituent for Ar ¹ and Ar ² include a monovalent heterocyclic residue which may be substituted with an alkyl group having 1 to 4 carbon atoms. .
Specific examples include a benzothiazolyl group and a thienyl group.

Examples of the aryl group which may have a substituent of Ar ³ include the same aryl groups as those which may have a substituent of Ar ¹ and Ar ² .
Specifically, phenyl group, o-tolyl group, m-tolyl group, p-tolyl group, 4-isopropylphenyl group, 3,4-dimethylphenyl group, 2-fluorophenyl group, 4-methoxyphenyl group, 2 , 4-dimethoxyphenyl group, 2-methyl-4-methoxyphenyl group, 2,5-dimethyl-4-methoxyphenyl group, 4-biphenylyl group, p-terphenyl group, 4-dimethylaminophenyl group, 4-triphenyl Fluoromethylphenyl group, 1-naphthyl group, 2-naphthyl group, 2-methyl-1-naphthyl group, 4-methyl-1-naphthyl group, 5-methyl-1-naphthyl group, 4-methoxy-1-naphthyl group 2-methyl-4-methoxy-1-naphthyl group, 4- (4-methyl-phenoxy) phenyl group, 4- (phenylthio) phenyl group, 2,5-dimethyl-4- Phenylthio) phenyl group.

Examples of the cycloalkyl group which may have a substituent for Ar ³ include a cycloalkyl group which may be substituted with an alkyl group having 1 to 4 carbon atoms.
Specifically, a cyclohexyl group, a cyclopentyl group, a 4,4-dimethylcyclohexyl group, etc. are mentioned.
Examples of the alkyl group that may have a substituent for Ar ³ include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a 2-thienylmethyl group, and a 1-naphthylmethyl group. Is mentioned.
Examples of the monovalent heterocyclic residue that may have a substituent for Ar ³ include a furyl group, a thienyl group, a 5-methyl-2-furyl group, a 5-methyl-2-thienyl group, and 5-methyl-N. -Ethylcarbazol-4-yl group.

Examples of the aryl group which may have a substituent for Ar ⁴ and Ar ⁵ include the same aryl groups as those which may have a substituent for Ar ³ .
Specifically, phenyl group, o-tolyl group, m-tolyl group, p-tolyl group, 4-isopropylphenyl group, 3,4-dimethylphenyl group, 2-fluorophenyl group, 4-chlorophenyl group, 4- (2-fluoroethyl) phenyl group, 4-methoxyphenyl group, 2,4-dimethoxyphenyl group, 2-methyl-4-methoxyphenyl group, 2,5-dimethyl-4-methoxyphenyl group, 4-biphenylyl group, p-terphenyl group, 4-dimethylaminophenyl group, 4-trifluoromethylphenyl group, 1-naphthyl group, 2-naphthyl group, 2-methyl-1-naphthyl group, 4-methyl-1-naphthyl group, 5 -Methyl-1-naphthyl group, 4-methoxy-1-naphthyl group, 6-methoxy-2-naphthyl group, 2-methyl-4-methoxy-1-naphthyl group, 9-a Tolyl, 1-pyrenyl, 4- (4-methyl-phenoxy) phenyl, 4- (phenylthio) phenyl, 2,5-dimethyl-4- (phenylthio) phenyl, p- (phenylthio) phenyl and Examples thereof include a p-styrylphenyl group.

Examples of the alkyl group which may have a substituent of Ar ⁴ and Ar ⁵ include, for example, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a trifluoromethyl group, and a fluoromethyl group. And 1-methoxyethyl group.
Examples of the monovalent heterocyclic residue that may have a substituent for Ar ⁴ and Ar ⁵ include the same alkyl groups that may have a substituent for Ar ³ .
Specifically, 8-chromanyl group, furyl group, thienyl group, 5-methyl-2-furyl group, 5-methyl-2-thienyl group, 5-methyl-N-ethylcarbazol-4-yl group, thiazolyl group Benzofuryl group, benzothiophenyl group, N-methylindolyl group, benzothiazolyl group, benzoxazolyl group and the like.

Ar ⁴ and Ar ⁵ may be bonded to each other via an atom or an atomic group to form a ring structure. Specific examples of the bonding atom include an oxygen atom and a sulfur atom. Specific examples of the bonding atom group include a divalent atomic group such as a nitrogen atom having an alkyl group, and methylene, ethylene, methylmethylene, and the like. Alkylene groups, unsaturated alkylene groups such as vinylene and propenylene, alkylene groups containing heteroatoms such as oxymethylene (chemical formula: —O—CH ₂ —), heterogeneous such as thiovinylene (chemical formula: —S—CH═CH—) And divalent groups such as an unsaturated alkylene group containing an atom.

Examples of the alkyl group which may have a substituent of a include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a trifluoromethyl group, a fluoromethyl group, and 1-methoxy. An ethyl group etc. are mentioned.
Examples of the alkoxy group which may have a substituent include a methoxy group, ethoxy group, n-propoxy group and isopropoxy group.
Examples of the dialkylamino group which may have a substituent a include a dimethylamino group, a diethylamino group, and a diisopropylamino group.
Examples of the aryl group that may have a substituent include a phenyl group, o-tolyl group, m-tolyl group, p-tolyl group, 4-methoxyphenyl group, and the like.
Examples of the halogen atom for a include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

Examples of the halogen atom for R ¹ include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.
Examples of the alkyl group which may have a substituent for R ¹ include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a trifluoromethyl group, a fluoromethyl group, and 1- A methoxyethyl group etc. are mentioned.

Examples of the alkyl group which may have a substituent of R ² , R ³ and R ⁴ include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a trifluoromethyl group, Examples thereof include a fluoromethyl group and a 1-methoxyethyl group.
Examples of the aryl group which may have a substituent for R ² , R ³ and R ⁴ include a phenyl group, an o-tolyl group, an m-tolyl group, a p-tolyl group, and a 4-methoxyphenyl group. .
Examples of the monovalent heterocyclic residue which may have a substituent for R ² , R ³ and R ⁴ include the same as those for Ar ¹ , Ar ² and Ar ³ .

Examples of the alkyl group which may have a substituent of b, c and d include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a trifluoromethyl group, and a fluoromethyl group. And 1-methoxyethyl group.
Examples of the alkoxy group which may have a substituent for b, c and d include a methoxy group, an ethoxy group, an n-propoxy group and an isopropoxy group.
Examples of the dialkylamino group which may have a substituent for b, c and d include a dimethylamino group, a diethylamino group and a diisopropylamino group.
Examples of the aryl group which may have a substituent for b, c and d include the same groups as those for Ar ¹ , Ar ² and Ar ³ .
Examples of the halogen atom for b, c and d include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.

Among the enamine compounds represented by the general formula (1), Ar ¹ and Ar ² are phenyl groups, and Ar ³ is a phenyl group and a tolyl group, particularly excellent from the viewpoints of characteristics, cost, and productivity. P-methoxyphenyl group, biphenylyl group, naphthyl group or thienyl group, and at least one of Ar ⁴ and Ar ⁵ is phenyl group, p-tolyl group, p-methoxyphenyl group, naphthyl group, thienyl group Or it is a thiazolyl group, R ¹ , R ² , R ³ and R ⁴ are all hydrogen atoms and n is 1.

Specific examples of enamine compounds represented by the sub-formula (II) are shown in Tables 1-1 to 1-21, but the present invention is not limited to these exemplified compounds.
Among these compounds, Exemplified Compounds 1, 43 and 111 are particularly preferable.
In addition, these compounds are compoundable by the method as described in Unexamined-Japanese-Patent No. 2004-151666.

The charge generation layer can be formed by a known dry method and wet method, but the latter is preferable.
Examples of the dry method include a method of vacuum-depositing a charge generating material on the surface of a conductive support.
As the wet method, for example, a coating solution for a charge generation layer is prepared by dissolving or dispersing in oxo titanyl phthalocyanine, an enamine compound represented by the general formula (I) and a binder resin in an appropriate organic solvent, and this coating solution is electrically conductive. The method of apply | coating to the undercoat layer surface formed on the adhesive support body, and then drying and removing an organic solvent is mentioned.
In the preparation of the coating solution for the charge generation layer, the coating and drying methods are the same as those for forming the undercoat layer.

The binder resin can improve the mechanical strength and durability of the charge generation layer, the binding property between layers, and the like, and a resin having a binding property used in this field can be used.
Specifically, melamine resin, epoxy resin, silicone resin, polyurethane resin, acrylic resin, vinyl chloride-vinyl acetate copolymer resin, vinyl chloride-vinyl acetate-maleic anhydride copolymer resin, vinyl chloride-vinyl acetate-polyvinyl alcohol Examples thereof include copolymer resins, polycarbonate resins, phenoxy resins, phenol resins, polyvinyl butyral resins, polyarylate resins, polyamide resins, and polyester resins. One or more of these can be used. Among these, polyvinyl butyral resin is preferable.

The weight ratio of oxo titanyl phthalocyanine to the enamine compound is 20/80 to 90/10, preferably 30/70 to 90/10.
When this weight ratio is less than 20/80, the charge generation amount is insufficient and the sensitivity may deteriorate. On the other hand, when the weight ratio exceeds 90/10, the charge separation / charge transport layer in the charge generation layer may not smoothly inject and the sensitivity may deteriorate.

  The charge generation layer is a chemical sensitizer, an optical sensitizer, an antioxidant, an ultraviolet absorber, a dispersion stabilizer, a sensitizer, a leveling agent, a plasticizer, as long as the preferable characteristics of the present invention are not impaired. An appropriate amount of one or more known additives selected from fine particles of inorganic compounds or organic compounds may be contained. These additives may be contained in the charge transport layer described later, or may be contained in both the charge generation layer and the charge transport layer.

  The chemical sensitizer and the optical sensitizer improve the sensitivity of the photoreceptor, suppress an increase in residual potential and fatigue due to repeated use, and improve electrical durability.

  Examples of chemical sensitizers include acid anhydrides such as succinic anhydride, maleic anhydride, phthalic anhydride, and 4-chloronaphthalic anhydride; cyano compounds such as tetracyanoethylene and terephthalmalondinitrile, 4-nitrobenzaldehyde, and the like. Aldehydes; anthraquinones such as anthraquinone and 1-nitroanthraquinone; polycyclic or heterocyclic nitro compounds such as 2,4,7-trinitrofluorenone and 2,4,5,7-tetranitrofluorenone; diphenoquinone compounds Examples thereof include electron-withdrawing materials and those obtained by polymerizing these electron-withdrawing materials.

  Examples of optical sensitizers include xanthene dyes, quinoline pigments, organic photoconductive compounds such as copper phthalocyanine, triphenylmethane dyes typified by methyl violet, crystal violet, knight blue and victoria blue; erythrosin, Acridine dyes typified by rhodamine B, rhodamine 3R, acridine orange and frappeocin; thiazine dyes typified by methylene blue and methylene green; oxazine dyes typified by capri blue and meldra blue; cyanine dyes; styryl dyes; Examples include pyrylium salt dyes and thiopyrylium salt dyes.

Antioxidants can maintain sensitivity stability over a long period of time.
Antioxidants include phenolic antioxidants such as hindered phenols such as 2,6-di-t-butyl-4-methylphenol (2,6-di-t-butyl-p-cresol: BHT). , Amine antioxidants such as hindered amines, vitamin E, hydroquinone, paraphenylenediamine, arylalkanes and derivatives thereof, organic sulfur compounds, organic phosphorus compounds, etc., and these may be used alone or in combination of two or more. Can be used.

Leveling agents and plasticizers can prevent itching and improve film formability, flexibility and surface smoothness.
Examples of the leveling agent include resiloxane and silicone leveling agent.
Examples of the plasticizer include dibasic acid esters such as phthalate esters, fatty acid esters, phosphate esters, chlorinated paraffins, and epoxy type plasticizers.

  Fine particles of an inorganic compound or an organic compound can enhance mechanical strength and improve electrical characteristics. Examples of such fine particles include fine particles of nitride compounds such as silicon nitride and aluminum nitride in addition to the metal oxide fine particles exemplified in the undercoat layer.

  Examples of the organic solvent include aromatic hydrocarbons such as toluene, xylene, mesitylene, tetralin, diphenylmethane, dimethoxybenzene, and dichlorobenzene; halogenated hydrocarbons such as dichloromethane, dichloroethane, and tetrachloropropane; tetrahydrofuran (THF) and dioxane. , Ethers such as dibenzyl ether, dimethoxymethyl ether and 1,2-dimethoxyethane; ketones such as methyl ethyl ketone, cyclohexanone, acetophenone and isophorone; esters such as methyl benzoate, ethyl acetate and butyl acetate, and diphenyl sulfide Sulfur-containing solvents; Fluorine solvents such as hexafluoroisopropanol; aprotic polar solvents such as N, N-dimethylformamide and N, N-dimethylacetamide Etc., and these may be used alone or as a mixed solvent. A mixed solvent obtained by adding alcohols, acetonitrile, or methyl ethyl ketone to such a solvent can also be used. Among these solvents, in consideration of the global environment, non-halogen organic solvents, in particular, a mixed solvent of two or more thereof are preferably used. Specifically, a mixed solvent of dimethoxyethane and cyclohexanone is most preferable.

  The thickness of the charge generation layer is not particularly limited, but is preferably 0.05 to 5 μm, particularly preferably 0.1 to 1 μm. When the thickness of the charge generation layer is less than 0.05 μm, the light absorption efficiency is lowered, and the sensitivity may be lowered. On the other hand, if the thickness of the charge generation layer exceeds 5 μm, charge transport within the charge generation layer becomes a rate-limiting step in the process of erasing the charge on the surface of the photoreceptor, and the sensitivity may be lowered.

[Charge transport layer 5]
The charge transport layer is provided on the charge generation layer, accepts the charge generated by the charge generation material, and has the ability to transport the charge transport material, binder resin, if necessary, a known plasticizer, sensitizer, etc. Containing.

The charge transport layer can be formed by a known wet method as with the charge generation layer.
Specifically, the charge transport material and the binder resin are dissolved or dispersed in a suitable solvent to prepare a coating solution for the charge transport layer, this coating solution is applied on the charge generation layer by a dip coating method, and dried to form a solvent. It is preferable to form by the method of removing.
The method for preparing, coating and drying the charge transport layer coating solution is in accordance with the method for forming the undercoat layer and the charge generation layer.

Examples of charge transport materials include poly-N-vinylcarbazole and derivatives thereof, poly-γ-carbazolylethyl glutamate and derivatives thereof, pyrene-formaldehyde condensates and derivatives thereof, polyvinylpyrene, polyvinylphenanthrene, oxazole derivatives, oxadiazole Derivatives, imidazole derivatives, 9- (p-diethylaminostyryl) anthracene, 1,1-bis (4-dibenzylaminophenyl) propane, styrylanthracene, styrylpyrazoline, pyrazoline derivatives, phenylhydrazones, hydrazone derivatives, triphenylamine Compounds, triphenylmethane compounds, stilbene compounds, azine compounds having a 3-methyl-2-benzothiazoline ring, fluorenone derivatives, dibenzothi Phene derivatives, indenothiophene derivatives, phenanthrenequinone derivatives, indenopyridine derivatives, thioxanthone derivatives, benzo (c) cinnoline derivatives, phenazine oxide derivatives, tetracyanoethylene, tetracyanoquinodimethane, bromanyl, chloranil, benzoquinone, etc. Can be mentioned.
When the photoreceptor is used in an image forming apparatus that uses a writing exposure light source (semiconductor laser light) whose exposure light source has a central oscillation wavelength at a wavelength of 360 to 420 nm, the charge transport material has a wavelength region of 360 nm or more. Arylamine compounds that do not absorb are particularly preferred.

The binder resin is preferably a material system that is compatible with the charge transport material and has no absorption at 360 nm or more. For example, polycarbonate and copolymer polycarbonate, polyarylate, polyvinyl butyral, polyamide, polyester, epoxy resin , Polyurethane, polyketone, polyvinyl ketone, polystyrene, polyacrylamide, phenol resin, phenoxy resin, polysulfone resin, and copolymer resins thereof. These binder resins may be used alone or in combination of two or more. Among these, resins such as polystyrene, polycarbonate, copolymer polycarbonate, polyarylate, and polyester have a volume resistivity of 10 ¹³ Ω or more, and are excellent in film formability and potential characteristics.

  Solvents that dissolve the binder resin include alcohols such as methanol and ethanol, ketones such as acetone, methyl ethyl ketone, and cyclohexanone, ethers such as ethyl ether, tetrahydrofuran, dioxane, and dioxolane, and aliphatic halogen carbonization such as chloroform, dichloromethane, and dichloroethane. Aromatics such as hydrogen, benzene, chlorobenzene and toluene can be mentioned.

  The ratio of the charge transport material in the charge transport layer is preferably in the range of 30 to 80% by weight, particularly preferably 40 to 70% by weight. When the ratio of the charge transport material is within the above range, the excellent effect of the present invention can be obtained.

The charge transport layer may contain an additive as exemplified in the charge generation layer.
In addition, filler particles may be added to the charge transport layer for the purpose of suppressing wear deterioration of the photoreceptor surface caused by slid printing with a cleaning blade of the image forming apparatus.
Such fillers are broadly classified into inorganic filler particles centered on organic filler particles and metal oxides.
In general, organic fillers mainly composed of fluorine-based materials are used for the purpose of controlling the wettability of the surface of the photoreceptor and suppressing the adhesion of foreign substances. On the other hand, inorganic fillers are mainly used for the purpose of improving printing durability, and the latter is preferably used in the present invention.

The inorganic filler particles are characterized by high material hardness and easy dispersion in the binder resin, such as silicon oxide (silica), titanium oxide, zinc oxide, calcium oxide, and aluminum oxide (alumina). Examples thereof include oxides and nitride compounds such as silicon nitride and aluminum nitride.
Among these, silicon oxide (silica) is particularly preferable because the difference from the refractive index of the medium is small considering light scattering.

  Further, the particle size (primary particle size) of the inorganic filler particles is preferably 100 nm or less, and particularly preferably in the range of 5 to 100 nm. The smaller the particle size, the smaller the scattering and adverse effects on the electric carriers in the system can be minimized. When the particle size is less than 5 nm or more than 100 nm, it is difficult to obtain the effect of addition.

  The thickness of the charge transport layer is preferably 10 to 30 μm, particularly preferably 10 to 20 μm. With a charge transport layer thickness of 20 to 30 μm that is usually applied, even if the beam diameter of the light source is reduced, in-plane diffusion of carriers occurs in the charge transport layer and the electrostatic latent image spreads, resulting in high resolution. Latent image formation is likely to be hindered. In order to prevent this, the thickness of the charge transport layer needs to be further reduced, and is preferably 10 to 20 μm.

[Protective layer (not shown)]
The photoreceptor of the present invention preferably has a crosslinkable (reactive) protective layer on the surface of the charge transport layer as a means for suppressing wear deterioration on the surface of the charge transport layer.
The protective layer is composed of a binder resin and, if necessary, the metal oxide fine particles, and the metal oxide fine particles in the charge transport layer is preferably about 0.1 to 30% by weight.
Moreover, it is preferable to add said charge transport material and antioxidant to a protective layer as needed, and potential stability and an image quality can be improved by addition.
The method for forming the protective layer is in accordance with the method for forming the undercoat layer.

The protective layer may be a crosslinkable (reactive) protective layer film using an organic silicon compound or the like.
Using an image forming apparatus provided with an exposure light source (writing light source) having a central oscillation wavelength at a wavelength of 360 to 420 nm, which will be described later, the photosensitive member of the present invention is charged and exposed to form an electrostatic latent image, As a means for developing the obtained electrostatic latent image, a high-resolution image can be formed even with the usual dry one-component or two-component development. The toner particles used preferably have a particle diameter of about 6 μm or less, and a low-viscosity liquid developer in which toner particles are dispersed in an organic solvent can also be used. In such a system, since the toner particle diameter is as small as about 1 μm or less and the charge amount is large, an output image with high resolution can be formed without image distortion. In order to improve the resistance to the organic solvent in such a case, it is useful to introduce the reactive protective layer film as described above.

  The image forming apparatus of the present invention is formed by exposure, the photosensitive member of the present invention, a charging unit for charging the photosensitive member, an exposure unit for exposing the charged photosensitive member to form an electrostatic latent image, and exposure. Developing means for developing the electrostatic latent image to form a toner image; transfer means for transferring the toner image formed by development onto a recording medium; and transferring the transferred toner image onto the recording material. A fixing unit that fixes and forms an image; a cleaning unit that removes and collects toner remaining on the photoconductor; and a neutralizing unit that neutralizes surface charge remaining on the photoconductor, and the exposure unit includes a wavelength unit. An exposure light source having a central oscillation wavelength of 360 to 420 nm is provided. The exposure light source is preferably a blue semiconductor laser.

The configuration of the image forming apparatus (laser printer) of the present invention and the image forming operation thereof will be described with reference to the drawings, but are not limited to the following description.
FIG. 4 is a schematic side view showing the configuration of the image forming apparatus of the present invention.

A laser printer 30 as an image forming apparatus includes a photosensitive member 1, a semiconductor laser 31, a rotary polygon mirror 32, an imaging lens 34, a mirror 35, a corona charger 36 as a charging unit, a developing unit 37 as a developing unit, and transfer paper. A cassette 38, a paper feed roller 39, a registration roller 40, a transfer charger 41 as a transfer means, a separation charger 42, a conveyor belt 43, a fixing device 44, a paper discharge tray 45, and a cleaner 46 as a cleaning means are configured. The
The semiconductor laser 31, the rotary polygon mirror 32, the imaging lens 34, and the mirror 35 constitute an exposure means 49.

  The photoreceptor 1 is mounted on the laser printer 30 so as to be rotatable in the direction of an arrow 47 by a driving unit (not shown). The laser beam 33 emitted from the semiconductor laser 31 is repeatedly scanned in the longitudinal direction (main scanning direction) with respect to the surface of the photoreceptor 1 by the rotary polygon mirror 32. The imaging lens 34 has an fθ characteristic, and the laser beam 33 is reflected by the mirror 35 to form an image on the surface of the photosensitive member 1 for exposure. By scanning the laser beam 33 as described above to form an image while rotating the photoconductor 1, an electrostatic latent image corresponding to image information is formed on the surface of the photoconductor 1.

The corona charger 36, the developing device 37, the transfer charger 41, the separation charger 42 and the cleaner 46 are provided in this order from the upstream side to the downstream side in the rotation direction of the photosensitive member 1 indicated by an arrow 47.
The corona charger 36 is provided upstream of the image forming point of the laser beam 33 in the rotation direction of the photoconductor 1 and uniformly charges the surface of the photoconductor 1. Therefore, the laser beam 33 exposes the surface of the photosensitive member 1 that is uniformly charged, and there is a difference between the charge amount of the part exposed by the laser beam 33 and the charge amount of the part not exposed. Electrostatic latent image is formed.
The charger is not limited to a corona charger, and may be a corotron charger, a scorotron charger, a sawtooth charger, a roller charger, or the like.

  The developing device 37 is provided downstream of the image forming point of the laser beam 33 in the rotation direction of the photosensitive member 1, supplies toner to the electrostatic latent image formed on the surface of the photosensitive member 1, and converts the electrostatic latent image into toner. Develop as an image. The transfer paper 48 accommodated in the transfer paper cassette 38 is taken out one by one by the paper feed roller 39 and is given to the transfer charger 41 by the registration roller 40 in synchronism with the exposure of the photoreceptor 1. The toner image is transferred onto the transfer paper 48 by the transfer charger 41. A separation charger 42 provided in the vicinity of the transfer charger 41 discharges the transfer paper onto which the toner image has been transferred and separates it from the photoreceptor 1.

The transfer paper 48 separated from the photoreceptor 1 is conveyed to the fixing device 44 by the conveying belt 43, and the toner image is fixed by the fixing device 44. The transfer paper 48 on which the image is formed in this manner is discharged toward the paper discharge tray 45. In addition, after the transfer paper 48 is separated by the separation charger 42, the photoreceptor 1 that continues to rotate further is cleaned of foreign matters such as toner and paper dust remaining on the surface by the cleaning blade of the cleaner 46 or the brush cleaner. The photosensitive member 1 whose surface has been cleaned by the cleaner 46 is neutralized by a neutralizing lamp (not shown) provided together with the cleaner 46 and then further rotated, and a series of image forming operations starting from the charging of the photosensitive member 1 is repeated. .
In addition, it is possible to employ a configuration in which a plurality of photosensitive members are provided to form a superimposed image using a plurality of different toners. This configuration is called a tandem system.

In the image forming apparatus according to the present invention, the polishing ability of the cleaning blade and the contact pressure of the cleaning blade against the surface of the photoconductor 1 can be set small, so that the life of the photoconductor 1 is extended. Further, since the surface of the photoreceptor 1 after cleaning is always kept in a clean state without adhesion of foreign matters such as toner and paper dust, an image with good image quality can be stably formed for a long period of time. .
That is, the image forming apparatus according to the present invention can stably form an image without deterioration in image quality over a long period of time in various environments. In addition, since the life of the photosensitive member 1 is long and the cleaner 46 has a simple configuration, an image forming apparatus with low cost and low maintenance frequency is realized. Furthermore, since the electrical characteristics of the photosensitive member 1 are not deteriorated even when exposed to light, it is possible to suppress deterioration in image quality due to the photosensitive member 1 being exposed to light during maintenance or the like.

The image forming apparatus of the present invention may have the following configuration in addition to that shown in FIG.
The photosensitive member 1 may be integrated with at least one selected from the corona charger 36, the developing unit 37, and the cleaner 46 to form a process cartridge.
For example, a process cartridge incorporating the photoreceptor 1, corona charger 36, developer 37 and cleaner 46, a process cartridge incorporating the photoreceptor 1, corona discharger 36 and developer 37, photoreceptor 1 and cleaner 46 are included. Examples of the process cartridge include a process cartridge in which the photosensitive member 1 and the developing unit 37 are incorporated.
By using a process cartridge in which several members are integrated in this way, maintenance management of the apparatus becomes easy.

When the outer diameter of the photoconductor is 40 mm or less, the separation charger 42 may be omitted. By devising the timing of applying a high voltage such as a developing bias, etc., a static elimination lamp (not shown) ) May be omitted.
That is, in the case of a photoconductor having a small diameter, a low-speed low-end printer, etc., the static elimination lamp can be omitted from the viewpoint of space saving.

  EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to these examples.

Example 1
A photosensitive layer was formed on a cylindrical conductive substrate made of aluminum having a diameter of 30 mm to produce a photoconductor, and its characteristics were evaluated.
7 parts by weight of titanium oxide (manufactured by Ishihara Sangyo Co., Ltd., product name: Taibake TTO55A) and 13 parts by weight of copolymer nylon (manufactured by Toray Industries, Inc., product name: Amilan CM8000 :), 159 parts by weight of methyl alcohol and 1,3 parts -In addition to a mixed solvent with 106 parts by weight of dioxolane, a coating shaker was used for dispersion treatment for 8 hours to prepare an undercoat layer coating solution (total amount: 1 kg).
The obtained coating liquid for undercoat layer was filled in a coating tank, the conductive support was dipped and then pulled up, and the obtained coating film was naturally dried to form an undercoat layer having a thickness of 1.0 μm.

  In advance, an oxotitanyl phthalocyanine represented by the following structural formula (A ′), which was used as a charge generation material as follows, was obtained.

29.2 g of diiminoisoindoline and 200 ml of sulfolane were mixed, and 17.0 g of titanium tetraisopropoxide was further added, followed by reaction at 140 ° C. for 2 hours in a nitrogen atmosphere. The resulting reaction mixture was allowed to cool, and the precipitate was collected by filtration, washed successively with chloroform, 2% aqueous hydrochloric acid, water and methanol, dried and bluish purple needle-like or plate-like compound (crystal) 25. 5 g was obtained.
As a result of chemical analysis of the obtained compound, it was confirmed that it was an oxotitanyl phthalocyanine represented by the above structural formula (yield 88.5%).

The obtained oxo titanyl phthalocyanine 1.8 parts by weight and butyral resin (manufactured by Sekisui Chemical Co., Ltd., product name: ESREC BX-1) 1.2 parts by weight, dimethoxyethane 105.3 parts by weight and cyclohexanone 11.7 parts. In addition to the mixed solvent with the parts by weight (mixing ratio = 90/10), a charge generating material-containing liquid was prepared by dispersing for 1 hour using a paint shaker.
Next, 5 parts by weight of enamine compound of Exemplified Compound 1, 4.4 parts by weight of polycarbonate (manufactured by Idemitsu Kosan Co., Ltd., product name: Taflon GH503) and polycarbonate (manufactured by Teijin Chemicals Ltd., product name: Panlite TS2040) 6 parts by weight was mixed, and 49 parts by weight of tetrahydrofuran (THF) was used as a solvent to prepare a charge generation layer addition liquid (total amount: 1 kg).

A charge generation layer coating liquid was prepared by adding 2.48 parts by weight of the charge generation layer addition liquid to 20 parts by weight of the charge generation material-containing liquid thus prepared, and stirring for 3 hours using a ball mill. That is, the charge generation material / enamine compound (weight ratio) in the charge generation layer was set to 60/40.
The obtained coating solution for charge generation layer was applied onto the previously formed undercoat layer by the same dip coating method as that for the undercoat layer, and the resulting coating film was naturally dried to obtain a film thickness of 0. A 3 μm charge generation layer was formed.

Next, 5 parts by weight of an arylamine compound represented by the following structural formula (B) as a charge transport material, 4.4 parts by weight of polycarbonate (manufactured by Idemitsu Kosan Co., Ltd., product name: Toughlon GH503) and polycarbonate (manufactured by Teijin Chemicals Ltd.) , Product name: Panlite TS2040) 3.6 parts by weight were mixed, and a coating solution for charge transport layer (total amount: 1 kg) was prepared using 49 parts by weight of tetrahydrofuran as a solvent.
The obtained charge transport layer coating solution was applied onto the charge generation layer formed earlier by the same dip coating method as that for the undercoat layer, and the obtained coating film was dried at a temperature of 120 ° C. for 1 hour. Thus, a charge transport layer having a thickness of 20 μm was formed to obtain a photoreceptor.

(Example 2)
In advance, an oxotitanyl phthalocyanine crystal represented by the structural formula (A ′), which was used as a charge generation material as follows, was obtained.
40 g of o-phthalodinitrile, 18 g of titanium tetrachloride and 500 ml of α-chloronaphthalene were reacted by heating and stirring at a temperature of 200 to 250 ° C. for 3 hours in a nitrogen atmosphere. Next, the mixture was allowed to cool to 100 to 130 ° C., filtered while hot, and washed with 200 ml of α-chloronaphthalene heated to 100 ° C. to obtain a crude product of dichlorotitanium phthalocyanine.
The obtained crude product was washed successively with 200 ml of α-chloronaphthalene and 200 ml of methanol at room temperature, and then subjected to hot washing in 500 ml of methanol for 1 hour. After filtration, the obtained crude product was repeatedly subjected to hot washing until the pH reached 6-7 in 500 ml of water. Then, it dried and the oxo titanyl phthalocyanine intermediate crystal was obtained. Next, the obtained intermediate crystal was mixed with methyl ethyl ketone, milled with glass beads having a diameter of 2 mm using a paint conditioner device (manufactured by Red Level), washed with methanol, and dried to obtain a crystal.

As a result of chemical analysis of the obtained crystal, it was confirmed to be oxotitanyl phthalocyanine.
Further, as a result of X-ray diffraction spectrum using CuKα ray (1.541Å) of the obtained crystal, Bragg angles (2θ ± 0.2 °) of 7.3 °, 9.4 °, 9.7 ° and 27 It was confirmed that the crystal was an oxotitanyl phthalocyanine crystal having a major diffraction peak at .3 ° and a maximum diffraction peak in a peak bundle of 9.4 ° and 9.7 ° (see FIG. 3).

  A photoconductor was prepared in the same manner as in Example 1 except that the oxotitanyl phthalocyanine crystal obtained by the above method was used in place of oxo titanyl phthalocyanine.

(Example 3)
The oxo titanyl phthalocyanine crystal of Example 2 was used in place of oxo titanyl phthalocyanine when preparing the charge generating material-containing liquid, and Exemplified Compound 43 was used instead of Exemplified Compound 1 when preparing the charge generating layer additive liquid. A photoconductor was prepared in the same manner as in Example 1 except that it was used.

Example 4
The oxo titanyl phthalocyanine crystal of Example 2 was used in place of oxo titanyl phthalocyanine when preparing the charge generating material-containing liquid, and Exemplified Compound 111 was used instead of Exemplified Compound 1 when preparing the charge generating layer additive liquid. A photoconductor was prepared in the same manner as in Example 1 except that it was used.

(Example 5)
The oxo titanyl phthalocyanine crystal of Example 2 was used in place of oxo titanyl phthalocyanine when preparing the charge generation material-containing liquid, and the charge generation material-containing liquid was added to 20 parts by weight when preparing the charge generation layer coating liquid. A photoconductor was prepared in the same manner as in Example 1 except that 0.41 part by weight of the charge generation layer additive solution was added. That is, the charge generation material / enamine compound (weight ratio) in the charge generation layer was set to 90/10.

(Example 6)
The oxo titanyl phthalocyanine crystal of Example 2 was used in place of oxo titanyl phthalocyanine when preparing the charge generation material-containing liquid, and the charge generation material-containing liquid was added to 20 parts by weight when preparing the charge generation layer coating liquid. A photoconductor was prepared in the same manner as in Example 1 except that 14.9 parts by weight of the charge generation layer additive solution was added. That is, the charge generation material / enamine compound (weight ratio) in the charge generation layer was set to 20/80.

(Example 7)
A photoconductor in the same manner as in Example 1 except that the oxotitanyl phthalocyanine crystal of Example 2 was used in place of oxotitanyl phthalocyanine when preparing the charge generating material-containing liquid, and that no undercoat layer was provided. Was made. That is, the charge generation material / enamine compound (weight ratio) in the charge generation layer was set to 60/40.

(Comparative Example 1)
Except that the oxo titanyl phthalocyanine crystal of Example 2 was used in place of oxo titanyl phthalocyanine when preparing the charge generation material-containing liquid, and the charge generation layer addition liquid was not added, the same as in Example 1. Thus, a photoconductor was prepared (without the addition of an enamine compound).

(Comparative Example 2)
The oxo titanyl phthalocyanine crystal of Example 2 was used in place of oxo titanyl phthalocyanine when preparing the charge generating material-containing liquid, and the following structural formula ( A photoconductor was prepared in the same manner as in Example 1 except that the triphenylamine compound (TPD) represented by C) was used. That is, the charge generation material / TPD (weight ratio) in the charge generation layer was set to 60/40.

(Comparative Example 3)
Except for using a perylene compound represented by the following structural formula (D) (manufactured by Clariant Japan Co., Ltd., product name: PV FAST RED B) instead of oxotitanyl phthalocyanine when preparing the charge generation material-containing liquid, A photoconductor was produced in the same manner as in Example 1. That is, the perylene compound / enamine compound (weight ratio) in the charge generation layer was set to 60/40.

(Evaluation)
Images of the photoconductors of Examples 1 to 7 and Comparative Examples 1 to 3 manufactured as described above, together with a charging member (Scotron Charger), each of a color composite machine (manufactured by Sharp Corporation, model: MX-4500N) An image composed of a collimator lens, an aperture, a cylinder lens, a polygon mirror, an fθ lens, a barrel-type toroidal lens, and a reflection mirror mounted on a process cartridge for a forming apparatus and using a semiconductor laser having a central oscillation wavelength of 405 nm as an image exposure light source Writing was performed with an exposure apparatus.
Two-component development (toner with a volume average particle size of 6.5 μm) is performed for development, a transfer belt (a toner image is directly transferred to a transfer paper) is used as a transfer member, and a 780 nm semiconductor laser is used for static elimination light. The entire surface of the photoreceptor was neutralized by light irradiation. The test environment was a temperature of 25 ° C. and a relative humidity of 50%.
Only the photoreceptor of Example 2 was also tested using a semiconductor laser having a central oscillation wavelength of 780 nm as an image exposure light source. This is referred to as Comparative Example 4.

<Electrical characteristics evaluation>
Using a surface potentiometer (manufactured by Trek Japan, model: model 344), the potential VL (-V) at the time of solid image printing was measured and judged according to the following criteria, which was used as an index of photoreceptor sensitivity.
VL <100 (V): No problem in actual use VL ≧ 100 (V): There is a problem in actual use because it affects the image density

<Evaluation of dot reproducibility>
A halftone image (1-dot image) was formed, and the dot formation state (dot reproducibility, dissipation state, and sharpness of the contour) was determined by visual observation based on the following criteria (rank).
◎: Good dot reproducibility, no dissipation, and excellent sharpness of the outline ○: Although there is a slight deterioration in the above three items, there is no problem in actual use △: Any of the three items is in actual use Problem x: Two or more of the three items are not actually usable. Table 2 shows the above evaluation results together with the constituent materials of the photoreceptor.

The following can be seen from the results in Table 2.
(1) The photoconductor of the present invention (Examples 1 to 7) containing oxotitanyl phthalocyanine and a specific amount of a specific enamine compound in the charge generation layer has photosensitivity to light having a wavelength of 360 to 420 nm. In a test using a semiconductor laser having a central oscillation wavelength of 405 nm as an image exposure light source, a high-quality image can be obtained. In particular, the photosensitizer (Examples 2 to 4) using a specific oxotitanyl phthalocyanine crystal can achieve particularly high sensitivity.

(2) In the photoconductor that does not contain an enamine compound in the charge generation layer (Comparative Example 1), light absorption in the charge generation layer is not sufficient, charge separation is not performed smoothly, and thus the sensitivity is low. it is conceivable that.
(3) In the photoreceptor (Comparative Example 2) containing TPD (triphenylamine compound) instead of enamine compound in the charge generation layer, TPD has no absorption band at a wavelength of 360 to 420 nm, and oxotitanyl phthalocyanine It is considered that sufficient sensitivity cannot be obtained because the light absorption is disturbed.

(4) In the photoreceptor (Comparative Example 3) containing a perylene compound instead of oxotitanyl phthalocyanine in the charge generation layer, even if the perylene compound has an absorption band at a wavelength of 360 to 420 nm, It is considered that charge injection is not good and sufficient sensitivity cannot be obtained. From this, it can be said that titanyl phthalocyanine is effective as the charge generation material of the present invention.

(5) Even with the photoreceptor of the present invention, the exposure at a wavelength of 780 nm (Comparative Example 4) causes the absorbance of the enamine compound to be 0% and hinders the light absorption of oxotitanyl phthalocyanine, so that sufficient sensitivity cannot be obtained. It is considered a thing.

1 Conductive support (conductive substrate)
2 Charge generation material 3 Charge generation layer 4 Charge transport material 5 Charge transport layer 6 Undercoat layer (intermediate layer)
7 Binder resin (binder resin)
21 Photosensitive layer (Multilayer type photosensitive layer)

1 Photoconductor 30 Laser printer (image forming device)
DESCRIPTION OF SYMBOLS 31 Laser 32 Rotating polygon mirror 33 Laser beam 34 Imaging lens 35 Mirror 36 Corona charger 37 Developing device 38 Transfer paper cassette 39 Paper feed roller 40 Registration roller 41 Transfer charger 42 Separation charger 43 Conveyor belt 44 Fixing device 45 Paper discharge Tray 46 Cleaner 47 Arrow 48 Transfer paper 49 Exposure means

Claims (7)

On the conductive support, at least a photosensitive layer in which a charge generation layer and a charge transport layer are laminated in this order is laminated,
The charge generation layer comprises oxotitanyl phthalocyanine as a charge generation material and general formula (I) as an additive:
[Where:
Ar ¹ and Ar ² are the same or different and are an aryl group which may have a substituent or a monovalent heterocyclic residue which may have a substituent, and Ar ¹ and Ar ² bind to them May be bonded to each other through a group of atoms or atomic groups to form a ring structure;
Ar ³ is an aryl group that may have a substituent, a cycloalkyl group that may have a substituent, an alkyl group that may have a substituent, or a monovalent complex that may have a substituent. A ring residue;
Ar ⁴ and Ar ⁵ are the same or different and each represents a hydrogen atom, an aryl group which may have a substituent, an alkyl group which may have a substituent, or a monovalent heterocyclic ring which may have a substituent A residue, Ar ⁴ and Ar ⁵ are not both hydrogen atoms, but may be bonded to each other via an atom or atomic group bonded to them to form a ring structure;
a represents an alkyl group which may have a substituent, an alkoxy group which may have a substituent, a dialkylamino group which may have a substituent, an aryl group which may have a substituent, a halogen atom; Or a hydrogen atom;
m is an integer of 1 to 6, and when m is 2 or more, a plurality of a may be the same or different and are bonded to each other via an atom or an atomic group bonded thereto to form a ring structure. Well;
R ¹ is a hydrogen atom, a halogen atom or an alkyl group which may have a substituent;
R ² , R ³ and R ⁴ are the same or different and are a hydrogen atom, an alkyl group which may have a substituent, an aryl group which may have a substituent, or a monovalent which may have a substituent. A heterocyclic residue of
n is an integer of 0 to 3, and when n is 2 or 3, a plurality of R ² and R ³ may be the same or different, and when n is 0, Ar ³ has a substituent. May be a monovalent heterocyclic residue]
And an enamine compound represented by the formula (1) in a weight ratio of 20/80 to 90/10, and has a photosensitive property to light having a wavelength of 360 to 420 nm. The enamine compound represented by the general formula (I) is a sub-formula (II):
[Where:
b, c and d are the same or different and each has an alkyl group which may have a substituent, an alkoxy group which may have a substituent, a dialkylamino group which may have a substituent, or a substituent. An aryl group, a halogen atom or a hydrogen atom, which may be
i, j and k are the same or different and are integers of 1 to 5, and when i, k or j is 2 or more, the corresponding plural b, c or d may be the same or different, and May be bonded to each other via an atom or atomic group bonded to the ring to form a ring structure;
Ar ⁴ , Ar ⁵ , a and m have the same meaning as in general formula (1)]
The electrophotographic photosensitive member according to claim 1, which is a compound represented by the formula: The enamine compound has the following formula:
The electrophotographic photoreceptor according to claim 1, wherein the electrophotographic photoreceptor is a compound selected from the group consisting of:   The oxo titanyl phthalocyanine exhibits a maximum diffraction peak at a Bragg angle (2θ ± 0.2 °) of 9.4 ° or 9.7 ° in an X-ray diffraction spectrum using a CuKα ray (1.541Å), and The electrophotographic photosensitive member according to claim 1, which is an oxotitanyl phthalocyanine crystal having diffraction peaks at least at 7.3 °, 9.4 °, 9.7 °, and 27.3 °.   The electrophotographic photosensitive member according to claim 1, further comprising an undercoat layer between the conductive support and the photosensitive layer. An electrophotographic photosensitive member according to claim 1, a charging means for charging the electrophotographic photosensitive member, and exposing the charged electrophotographic photosensitive member to form an electrostatic latent image. An exposure unit; a development unit that develops the electrostatic latent image formed by exposure to form a toner image; a transfer unit that transfers the toner image formed by development onto a recording medium; and the transferred unit Fixing means for fixing a toner image on the recording medium to form an image; cleaning means for removing and collecting toner remaining on the electrophotographic photosensitive member; and removing surface charges remaining on the electrophotographic photosensitive member. Comprising at least static elimination means,
An image forming apparatus, wherein the exposure means includes an exposure light source having a central oscillation wavelength at a wavelength of 360 to 420 nm.   The image forming apparatus according to claim 6, wherein the exposure light source is a blue semiconductor laser.