JP5521947B2 - Organic photoreceptor and image forming apparatus - Google Patents

Description

  The present invention relates to an organic photoreceptor (hereinafter simply referred to as a photoreceptor) that can cope with image formation with extremely high image quality in the field of light printing and the like, and an image forming apparatus.

  In recent years, the image quality of a printing system using a dry electrophotographic system has been improved, and has been widely used in the printing field with a relatively small number of copies. As a result, the required image quality has further increased, and methods that have been rarely used in the past, such as printing on coated paper, printing of high coverage images, mass printing of high-quality images, etc., have come to be used frequently. . As a result, the occurrence of problems that have not been pointed out in the past has increased.

  One of them is the generation of an interference streak pattern of a halftone image which is considered to be caused by the exposure pattern and the cutting cycle of the photoreceptor substrate surface. This is a problem that has frequently occurred in recent years due to a combination of a request for improving the uniformity of the intermediate color, an improvement in the performance of the image forming apparatus, and the use of coated paper.

  Incidentally, conventionally, the concavo-convex shape of the surface of the photoreceptor substrate has been devised (for example, Patent Documents 1 to 3). These countermeasures are effective as countermeasures against interference fringes, which has been a problem in the past. However, when a high-quality image is produced on a coated paper with a photoconductor having a concavo-convex substrate surface according to these countermeasures, there is a problem that a streak pattern based on the concavo-convex shape becomes apparent.

  In addition, an electrophotographic image using coated paper provides a high-quality image with multiple gradations compared to an electrophotographic image of plain paper, but gradation unevenness occurs on a photoconductor having an uneven substrate surface. There is also a problem that it is easy.

  In other words, the conventional processing of the concavo-convex photoconductor substrate has a sufficient effect on the image quality level output to plain paper in the office, which has been the mainstream, but demand has increased in recent years. In a high-quality output image (for example, output on coated paper in the light printing field), a new image defect based on the uneven shape is generated.

Japanese Patent No. 3480618 JP 2003-91085 A Japanese Patent No. 3894023

  The object of the present invention is to solve the problems described above. In other words, high image quality when forming electrophotographic images on coated paper, image defects of streak patterns that are likely to occur in high-gradation electrophotographic images, occurrences of black spots and uneven gradation, and image quality defects are solved. Another object is to provide an organic photoreceptor capable of providing a high-gradation electrophotographic image, and to provide an image forming apparatus using the organic photoreceptor.

  The inventors of the present invention use the photoconductive substrate on the charge generation layer of the photoconductor, along with the periodic shape of the substrate, that the periodic uneven shape of the photoconductor substrate formed by the cutting tool tends to appear in the image defect described above. And the present invention has been achieved.

  In other words, as a measure for eliminating streak failure, when the machining method that disturbs the periodicity of the substrate is performed, the relative speed between the raw pipe to be cut and the cutting tool changes. It has been found that fine burrs and burrs are likely to occur in the shape, and in particular, in the environment of high temperature and high humidity, the occurrence of spots caused by defective parts of the raw tube becomes a problem. In order to solve this problem, the present invention has been achieved by finding that it is effective to use a pigment that has high sensitivity to the charge generation material and whose charge generation layer has a small sensitivity fluctuation with respect to the film thickness fluctuation.

  That is, the object of the present invention is achieved by taking the following configuration.

  1. In an organic photoreceptor having at least a charge generation layer and a charge transport layer on a cylindrical substrate, the cylindrical substrate has a concavo-convex shape formed on the outer peripheral surface along the central axis, and processing the concavo-convex shape Reflection at 700 nm of the reflection spectrum of the charge generation layer, wherein the difference in period (ΔL) satisfies Equation 1 and the charge generation layer comprises a pigment containing titanyl phthalocyanine and 2,3-butanediol adduct titanyl phthalocyanine An organic photoreceptor, wherein the ratio (R700 / R780) of the ratio (R700) to the reflectance (R780) at 780 nm is 0.8 to 1.3.

  However, the reflectance is a reflectance measured by forming the charge generation layer on the aluminum support, and is a relative reflectance when the reflectance of the aluminum support is 100%.

Formula 1 10μm ≦ ΔL
(However, ΔL is the difference in the machining cycle in the central axis direction within the image area of the cylindrical substrate.)
2. 2. The organophotoreceptor according to 1 above, wherein the pigment has a peak at 8.3 ° of a Bragg angle (2θ ± 0.2 °) in an X-ray diffraction spectrum.

  3. The organic photoreceptor described in 1 or 2 above, means for forming an electrostatic latent image on the organic photoreceptor, means for developing the electrostatic latent image with toner, means for transferring the formed toner image to an image support, An image forming apparatus comprising at least means for fixing a toner image after transfer.

  By using the organophotoreceptor of the present invention, it is possible to solve the image defects of streaks, black spots, and uneven gradation that are likely to occur in high-quality, high-gradation electrophotographic images obtained with coated paper. An organic photoreceptor capable of providing an electrophotographic image with high image quality and high gradation can be provided, and an image forming apparatus using the organic photoreceptor can be provided.

The schematic diagram explaining the stripe-shaped density unevenness of the last screen made into the subject by this invention. The schematic diagram explaining the film thickness fluctuation | variation of the electric charge generation layer by the cutting pitch of an electroconductive base | substrate surface. The figure explaining the measuring method of (DELTA) L in this invention. 1 is a configuration diagram of a color image forming apparatus using an electrophotographic photosensitive member of the present invention. Explanatory drawing which illustrated the exposure pattern of the halftone. It is a figure of an example of the reflection spectrum of the photosensitive layer containing the pigment of this invention. It is a figure of an example of the X-ray-diffraction spectrum of the photosensitive layer using the pigment containing 2, 3- butanediol adduct titanyl phthalocyanine.

  The present invention will be further described.

  The failure that is the subject of the present invention is a phenomenon in which diagonal stripe density unevenness occurs on the screen as shown in FIG. 1, and is conspicuous in a uniform image. In particular, it is regarded as a problem in a large-screen high-quality image such as light printing on a smooth image. This unevenness was particularly remarkable in a low temperature and low humidity environment.

  According to the inventor's study, the cause of the interference streaking that is a problem in the present invention is as follows.

  The interference streaks are not caused by the substrate itself of the photoconductor, but the amount of the charge generation layer (CGL) coating solution is periodically changed to reflect the surface shape of the substrate. The local sensitivity fluctuation is caused by having periodicity. That is, the periodic exposure by a laser beam, an LED light source, or the like is performed on a photoconductor in which the film thickness of the charge generation layer as shown in FIG. 2 fluctuates with periodicity (therefore, sensitivity changes with periodicity). When it is performed, streaky density unevenness occurs due to the sensitivity changing with periodicity and the interference of exposure.

  The gist of the present invention is that it is found that changing the width of the periodic unevenness caused by cutting on the surface of the cylindrical conductive substrate more than a certain degree is extremely effective in reducing interference streak failure. It has been found that even when required, a good image can be formed by using a pigment having good dispersibility of the pigment and low humidity dependency.

  The periodic uneven shape can be formed by cutting, nozzle processing (blasting abrasive from the nozzle tip) or the like while rotating the cylindrical substrate.

  In order to set ΔL, which is an index of irregularity, to 10 μm or more, it is necessary to frequently change the machining cycle width when the surface of the substrate is shaped by cutting. For this purpose, an instruction to frequently change the moving speed of the cutting tool with respect to the surface of the photosensitive member during processing may be added.

For example, in the case of a CNC lathe that indicates the moving speed X (mm / rev) of the tool and its indicated position Y (mm), (X ₁ , Y ₁ ), (X ₂ , Y ₂ ),... (X _n , Y _n ) and n blocks are programmed. For example, in the m-th block, when (Y _{m + 1} −Y _m ) / X _m is not an integer, the byte movement speed is set to enable switching at the end of the block. In the next m + 1th block, the speed is increased to the designated speed _{Xm + 1} . This can be used to change the moving speed of the byte.

  Further, in the case of an analog lathe that is not CNC, it is possible to change the moving speed of the cutting tool by outputting the motor voltage that controls the moving speed of the cutting tool, for example, through a circuit that switches a plurality of resistors. Further, for example, it is possible to move the byte using a power source capable of outputting a voltage having a specified waveform. Further, setting ΔL to 10 μm or more can be realized by appropriately changing the rotation of the conductive substrate during processing. This can be achieved by the same means as in the analog lathe described above.

  In order to further reduce the periodicity, it is desirable that the instruction interval for changing the moving speed is not constant. For example, in the case of the above-mentioned CNC lathe, Yn is not constant, and in the case of the above-mentioned analog lathe, a plurality of switching timers are used, and the output waveform can be complicated by superimposing different waveforms. This can be achieved by using

  The processed surface shape in which the cylindrical conductive substrate of the photoreceptor is regularly formed in the direction along the central axis means that the substrate is centered when the surface of the substrate is molded by cutting or nozzle processing. This is an uneven shape that is generated by machining while moving the cutting tool or nozzle in contact with or close to each other while moving in the central axis direction while rotating the tool. To change the machining cycle width, for example, change the moving speed of the tool or nozzle. It can be obtained by performing the same.

  When an intermediate layer is provided on a cylindrical conductive substrate and a charge generation layer is formed on the intermediate layer (UCL), the surface shape of the base is the surface shape of the intermediate layer. It is mainly determined by the surface shape of the cylindrical conductive substrate and the composition of the intermediate layer (FIG. 2 illustrates this case).

  From the above, it is effective to reduce the periodicity of the amount of the charge generation layer coating solution applied to the photoconductor for the reduction of the interference streak of the present invention. It is considered effective to reduce the periodicity of the tube shape in the scanning direction. Further, if an intermediate layer containing fine particles is used, the surface has a random convex shape derived from the particle shape, and the shape periodicity derived from the raw tube can be reduced, which is effective in reducing interference streak failure. . For the above reasons, ΔL is 10 μm or more, preferably 10 μm to 200 μm, and more preferably 10 μm to 100 μm.

(Measurement method of ΔL)
The difference ΔL in the machining cycle in the central axis direction within the image region of the cylindrical conductive substrate in the present invention is calculated by reading the machining cycle from the cross-sectional curve or roughness curve of the machined surface as exemplified in FIG. can do. That is, attention is paid to the repeated shape and period from the spectrum diagram on the upper side of FIG. 3, and the period length is read by increasing the magnification appropriately. In the case of the spectrum diagram on the lower side of FIG. 3, the lateral magnification is set to 4 times.

  The measurement location may be any location within the image area of the cylindrical conductive substrate.

  The measurement length of the machining surface may be any length as long as the machining cycle can be read, but is preferably such that the machining cycle can be read by at least 5 cycles or more, and particularly preferably 10 cycles or more.

  As the measurement location, for example, the vicinity of the center in the axial direction of the cylindrical conductive substrate is selected, and as the measurement length, for example, about 4 mm is selected.

  In addition, the measurement of the cross-section curve or the roughness curve is not particularly limited as long as the machining cycle can be read from each curve, but for example, a non-contact type using a stylus type surface roughness measuring instrument, a laser, etc. A surface analysis device or the like is used.

Examples of using a stylus type surface roughness measuring instrument include the following conditions.
Measuring instrument: Tokyo Seimitsu Surfcom 1400D
Measurement mode: Roughness measurement (JIS '01 standard)
Measurement length: 4.0 mm
Cut-off: 0.8mm (Gaussian)
Measurement speed: 0.3 mm / sec
In the present invention, the difference between the maximum value and the minimum value of the cutting cycle read from the cross-sectional curve or roughness curve measured in this way is defined as ΔL.

[Organic photoconductor composition]
The general structure of the organic photoreceptor is described below.

  In the present invention, the organic photoconductor means an electrophotographic photoconductor constituted by giving an organic compound at least one of a charge generation function and a charge transport function indispensable for the constitution of the electrophotographic photoconductor. In this case, the photosensitive member is composed of a known organic charge generating material or organic charge transporting material. Further, since it contains all known organic photoreceptors such as a photoreceptor having a charge generation function and a charge transport function with a polymer complex, it may be referred to as an organic photoreceptor in the following description.

  The organophotoreceptor of the present invention has at least a charge generation layer and a charge transport layer on a cylindrical conductive substrate, or further a protective layer sequentially laminated. Specifically, as shown below, The layer configuration can be exemplified.

1) A layer structure in which a charge generation layer and a charge transport layer as an intermediate layer, a photosensitive layer, and, if necessary, a protective layer are sequentially laminated on a cylindrical conductive substrate,
2) A layer structure in which an intermediate layer, a single layer containing a charge transport material and a charge generation material as a photosensitive layer, and a protective layer as necessary are sequentially laminated on a cylindrical conductive substrate.

  Hereinafter, the layer structure of the organic photoreceptor of the present invention will be described focusing on the above 1).

(Cylindrical conductive substrate)
The cylindrical conductive substrate (also referred to as a cylindrical conductive support) used in the present invention may be any cylindrical one having conductivity, such as aluminum, copper, chromium, nickel, zinc, and the like. Metals such as stainless steel molded into a drum shape or cylinders, plastic drums with metal foils such as aluminum and copper formed on plastic drums, aluminum, indium oxide and tin oxide plastic Examples include a material deposited on a drum, a metal provided with a conductive layer by applying a conductive material alone or with a binder resin, a plastic drum, etc. Any material and configuration may be used as long as the shape of the present application can be formed. .

(Middle layer)
In the present invention, an intermediate layer having a barrier function and an adhesive function may be provided between the conductive layer and the photosensitive layer. Considering various types of failure prevention, it can be said that providing an intermediate layer is a preferable mode.

  The intermediate layer can be formed by dip coating or the like by dissolving a binder resin such as casein, polyvinyl alcohol, nitrocellulose, ethylene-acrylic acid copolymer, polyamide, polyurethane and gelatin in a known solvent. Of these, an alcohol-soluble polyamide resin is preferred.

  Moreover, various fine particles (metal oxide particles and the like) can be contained for the purpose of adjusting the resistance of the intermediate layer. For example, using various metal oxides such as alumina, zinc oxide, titanium oxide, tin oxide, antimony oxide, indium oxide, and bismuth oxide, fine particles such as indium oxide doped with tin, tin oxide doped with antimony, and zirconium oxide. Can do.

  You may use these metal oxides 1 type or in mixture of 2 or more types. When two or more types are mixed, it may take the form of a solid solution or fusion. The average particle diameter of such a metal oxide is preferably 0.3 μm or less, more preferably 0.1 μm or less. These metal oxide particles may be surface-treated with an inorganic compound or an organic compound.

  As the solvent used for the intermediate layer, a solvent in which inorganic particles are well dispersed and the polyamide resin is dissolved is preferable. Specifically, alcohols having 1 to 4 carbon atoms such as methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n-butanol, t-butanol and sec-butanol are excellent in solubility and coating performance of polyamide resin. preferable. In addition, examples of co-solvents that can be used in combination with the above-described solvent to obtain favorable effects in order to improve the storage stability and particle dispersibility include benzyl alcohol, toluene, methylene chloride, cyclohexanone, and tetrahydrofuran.

  The density | concentration of binder resin is suitably selected according to the film thickness and production rate of an intermediate | middle layer.

  The mixing ratio of the inorganic particles to the binder resin when the inorganic particles are dispersed is preferably 20 to 400 parts by mass, more preferably 50 to 200 parts by mass with respect to 100 parts by mass of the binder resin.

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

  The method for drying the intermediate layer can be appropriately selected according to the type of solvent and the film thickness, but thermal drying is preferred.

  The thickness of the intermediate layer is preferably from 0.1 to 30 μm, more preferably from 0.3 to 15 μm.

(Charge generation layer)
The charge generation layer contains a charge generation material (CGM). Other substances may contain a binder resin and other additives as necessary.

  A pigment containing titanyl phthalocyanine and 2,3-butanediol adduct titanyl phthalocyanine (hereinafter also referred to as the pigment of the present invention) is used as the charge generation material of the charge generation layer of the present invention. When the pigment of the present invention is used for the charge generation layer, it has high sensitivity characteristics, and the sensitivity variation with respect to the change in the film thickness of the charge generation layer is relatively small, so that the object of the present invention can be improved more effectively. Can do.

  Generally, the charge generation layer is formed by coating and drying a coating solution in which a charge generation material is dispersed in a solution in which a binder resin is dissolved in an organic solvent. In order to enhance the electrical characteristics and image characteristics of the photoreceptor, it is considered important to uniformly disperse the charge generating material in the photosensitive layer. When the dispersion is insufficient, coarse particles are contained in the coating solution, and as a result, the charge generation layer formed using the coating solution also contains coarse particles of the charge generation material, and the electrical characteristics And image characteristics deteriorate. Therefore, in the process of preparing the charge generation layer coating solution, it is important to sufficiently disperse the charge generation material so that the coating solution does not contain secondary agglomerated particles or coarse particles.

  On the other hand, when the dispersibility of the charge generation material is increased by a high dispersion share, a uniformly dispersed coating film can be formed, but the crystal structure of the charge generation material is changed by the dispersion share and its characteristics are impaired, and sensitivity and potential stability are stabilized. May cause problems with sex.

  The present inventors have found that the pigment containing the titanyl phthalocyanine of the present invention and the 2,3-butanediol adduct titanyl phthalocyanine is a product of butanediol due to hydrolysis or the like in a crystal defect portion generated on a fracture surface or the like formed when pulverized. It was inferred that detachment and decomposition of the phthalocyanine ring are likely to occur, and that the degradation product may inhibit charge generation or become a charge trap, adversely affecting sensitivity and repeatability.

  In accordance with this reasoning, the present invention has attempted to increase dispersibility without putting too much stress on the pigment crystal. As a result, we can synthesize small particle size pigment particles, and we can solve the problem by carrying out low share dispersion that only loosens the secondary agglomeration without crushing while maintaining the crystals at the time of pigment synthesis. As a result of continuing the examination, as a guide, the ratio (R700 / R780) of the reflectance (R700) at 700 nm and the reflectance (R780) at 780 nm of the reflection spectrum of the charge generation layer containing the pigment of the present invention is dispersed. It has been found that it can serve as an index indicating the degree of compatibility between crystallinity and crystallinity maintenance.

  According to the results of the study by the present inventors, when the ratio (R700 / R780) of the charge generation layer is 0.8 to 1.3, the sensitivity does not depend on humidity, but the sensitivity is high. Thus, it was found that an electrophotographic photoreceptor having a high potential stability repeatedly can be obtained.

  FIG. 6 is an example of the reflection spectrum of the photosensitive layer containing the pigment of the present invention.

  FIG. 6A shows a characteristic in which the ratio of reflection spectrum (R700 / R780) is within the scope of the present invention.

  FIG. 6B shows a characteristic in which the ratio of reflection spectrum (R700 / R780) is outside the range of the present invention.

  The pigment containing titanyl phthalocyanine of the present invention and 2,3-butanediol adduct titanyl phthalocyanine is a pigment containing at least titanyl phthalocyanine and 2,3-butanediol adduct titanyl phthalocyanine in one pigment particle. Means.

  In the dispersion of the pigment of the present invention, the reflectance near 780 nm increases and the ratio (R700 / R780) decreases as the dispersion of secondary aggregation and the crushing of crystals progress.

  When the ratio (R700 / R780) is less than 0.8, it indicates that the pigment crystal was crushed due to excessive dispersion share, and the 2,3-butanediol adduct titanyl phthalocyanine tends to be decomposed at the defective portion of the crystal. As a result, sensitivity and repetitive characteristics deteriorate.

  On the other hand, when the ratio (R700 / R780) exceeds 1.3, it indicates that secondary aggregated particles or coarse particles with poor dispersion are present, and image defects such as a decrease in image density occur.

  In the present invention, the reflection spectrum of the charge generation layer is measured with a sample in which the charge generation layer is formed on an aluminum support with a dry film thickness of 0.3 μm. The reflection spectrum is measured as a relative reflectance when the reflectance of the aluminum support is 100%. In order to remove irregularities due to interference fringes in the obtained reflection spectrum, the measurement data is approximated by a second order polynomial in the range of 685 to 715 nm and 765 to 795 nm, and the reflectance (R700) and reflectance (R780) are calculated. The ratio (R700 / R780) is calculated.

  The reflection spectrum was measured by using an optical film thickness measuring device Solid Lambda Thickness (Spectra Corp.).

  The 2,3-butanediol adduct titanyl phthalocyanine pigment is synthesized as shown by the following chemical reaction.

  The 2,3-butanediol adduct titanyl phthalocyanine pigment has its specific crystal form due to the difference in the addition ratio of butanediol.

  For the crystal types described below, FIG. 7 illustrates an example of an X-ray diffraction spectrum of a photosensitive layer using a pigment containing a 2,3-butanediol adduct titanyl phthalocyanine.

  When an excess of titanyl phthalocyanine and at least one of (2R, 3R) -2,3-butanediol or (2S, 3S) -2,3-butanediol (hereinafter also referred to as butanediol) is reacted, In the diffraction spectrum, a pigment having a characteristic peak at a Bragg angle 2θ (± 0.2 °): 9.5 ° (hereinafter abbreviated as 9.5 ° type) is obtained as shown in FIG. The 9.5 type butanediol-added titanyl phthalocyanine pigment has peaks at 16.4 °, 19.1 °, 24.7 °, and 26.5 ° in addition to 9.5.

Structure of the pigment Ti = O absorption near 970 cm ^-1 in the IR spectrum disappeared, 630 cm ^-1 of the absorption of the O-Ti-O appears in the vicinity about the 390 to 410 ° C. in a thermal analysis (TG) 11 % Mass loss (possibly due to the elimination of butylene oxide by thermal decomposition), and from the results of mass spectrometry, titanyl phthalocyanine and (2R, 3R) -2,3-butanediol or (2S, 3S ) -2,3-butanediol is considered to have a dehydrated condensation structure at 1/1.

On the other hand, when a butanediol compound is reacted at 1 mol or less with respect to 1 mol of titanyl phthalocyanine, the powder X-ray diffraction spectrum has a characteristic peak at a Bragg angle 2θ: 8.3 ° (± 0.2 °) ( Hereinafter, the pigment shown in FIG. 7 (2) is obtained. The 8.3 ° butanediol-added titanyl phthalocyanine pigment has peaks at 24.7 °, 25.1 °, and 26.5 ° in addition to 8.3 °. The pigment shows both absorption of Ti = O near 970 cm ⁻¹ and O—Ti—O near 630 cm ⁻¹ in the IR spectrum. In addition, from the result of mass analysis that the mass loss is less than 11% at 390 to 410 ° C. by thermal analysis and from the result of mass analysis, butanediol / titanyl phthalocyanine = 1/1 adduct and titanyl phthalocyanine are mixed at a certain ratio ( It is presumed that two or more compounds are mixed in one pigment particle to form a pigment having a specific crystal type. The butanediol addition ratio is estimated to be 40 to 70 mol% from the mass loss of 390 to 410 ° C. in the thermal analysis.

  In the X-ray diffraction spectrum, the characteristic peak means a clearly different peak exceeding the background variation.

  In the present invention, the pigment of the present invention is characterized by at least a Bragg angle (2θ ± 0.2 °) of 8.3 ° in the X-ray diffraction spectrum in that good sensitivity and repeated potential stability can be obtained. More preferably, it has a peak.

  In the present invention, for synthesis of 2,3-butanediol adduct titanyl phthalocyanine, the optical material of (2R, 3R) -2,3-butanediol or (2S, 3S) -2,3-butanediol is used as a raw material. The isomeric 2,3-butanediol is preferably used, but a racemate that does not exhibit optical isomerism may be used.

The pigment of the present invention is a pigment at the time of synthesis and desirably has a BET specific surface area of 20 m ² / g or more.

  Thus, when the coating solution of the charge generation layer containing a pigment having a large BET specific surface area and a small particle size is dispersed in a low shear to maintain the dispersibility of the pigment during synthesis, good sensitivity and repeated potential are obtained. A photosensitive member having stability can be produced.

[Method for producing 2,3-butanediol adduct titanyl phthalocyanine]
2,3-butanediol adduct titanyl phthalocyanine, for example, an adduct of titanyl phthalocyanine and at least one of (2R, 3R) -2,3-butanediol or (2S, 3S) -2,3-butanediol, Titanyl phthalocyanine and (2R, 3R) -2,3-butanediol or (2S, 3S) -2,3-butanediol (hereinafter sometimes referred to as butanediol compound) in various solvents at room temperature or under heating It can be synthesized by reacting. The raw material titanyl phthalocyanine can be synthesized from phthalonitrile and titanium tetrachloride, synthesized from diiminoisoindoline and alkoxy titanium, or synthesized from phthalonitrile, urea and alkoxy titanium. The method can also be used, but high purity titanyl phthalocyanine with a low chlorine content obtained from diiminoisoindoline and alkoxytitanium is particularly preferred. The titanyl phthalocyanine is preferably made amorphous by a method such as acid paste treatment and then reacted with a butanediol compound. For the addition reaction between amorphous titanyl phthalocyanine and a butanediol compound, usually 5 to 30 times the solvent is used. The solvent is not particularly limited, and aromatic solvents such as chlorobenzene, dichlorobenzene, anisole, chloronaphthalene and quinoline to ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone and acetophenone, ether solvents such as tetrahydrofuran, dioxolane and diglyme, Furthermore, there can be mentioned a large number of aprotic polar solvents such as dimethylformamide, dimethylacetamide and dimethylsulfoxide, other halogen-based solvents and ester-based solvents.

The reaction between titanyl phthalocyanine and a butanediol compound is shown below. The reaction can be carried out under a wide range of temperature conditions, the reaction temperature is preferably in the range of 25 to 300 ° C., and a pigment having a BET specific surface area of 20 m ² / g or more. In order to synthesize | combine, it is more preferable that it is the range of 30-100 degreeC.

  The butanediol compound is usually added at a ratio of 0.2 to 2.0 mol with respect to 1 mol of titanyl phthalocyanine. In order to be an equimolar adduct, the diol compound must be used in an amount of 1.0 mol or more. When the diol compound is added in an amount of 1.0 mol or less in the above ratio, the obtained adduct becomes a mixed crystal with titanyl phthalocyanine.

[Dispersion of the pigment of the present invention]
In order to make a dispersion liquid such as a charge generation layer using the pigment of the present invention (a pigment containing titanyl phthalocyanine and 2,3-butanediol adduct titanyl phthalocyanine), these pigments are dispersed in a solvent. There are no particular restrictions on the solvent, and ketone solvents such as methyl ethyl ketone, methyl isopropyl ketone, methyl isobutyl ketone, cyclohexanone, and acetophenone, ether solvents such as tetrahydrofuran, dioxolane, and diglyme, and alcohol solvents such as methyl cellosolve, ethyl cellosolve, and butanol There may be mentioned a large number of solvents, ester solvents such as ethyl acetate and t-butyl acetate, aromatic solvents such as toluene and chlorobenzene, and halogen solvents such as dichloroethane and trichloroethane.

  A binder can be added to the dispersion. The binder can be selected widely as long as it is soluble in the solvent used. Examples include polyvinyl butyral, polyvinyl formal, polyvinyl acetate, polyvinyl chloride, polyamide, polycarbonate, polyester, and copolymers thereof. The ratio of the binder and the pigment is not particularly limited, but is usually 1/10 to 10/1. When the amount of the binder is small, the dispersion becomes unstable, and when the amount is too large, the electric resistance is increased, and when the electrophotographic photosensitive member is formed, the residual potential tends to increase repeatedly.

  The dispersion means preferably used in the present invention is the above-described low shear dispersion (low shear dispersion). As the low shear dispersion, ultrasonic dispersion or a medium having a small specific gravity (glass (specific gravity: 2.5)). Media dispersion using beads or the like is preferred.

  As an indicator of the dispersion state, the ratio of the reflection spectrum of the charge generation layer (R700 / R750) needs to be in the range of 0.8 to 1.3. Control of the ratio of these reflection spectra (R700 / R750) can be performed by adjusting the share applied to the dispersion during dispersion. Specifically, it can be controlled by the dispersion method, the diameter and amount of media used during dispersion, the dispersion time, and the like.

  By combining the charge generation layer containing the 2,3-butanediol adduct titanyl phthalocyanine pigment of the present invention with the conductive substrate having the ΔH characteristic of the present invention, the effects of the present invention can be achieved more remarkably. .

  In addition to the 2,3-butanediol adduct titanyl phthalocyanine pigment of the present invention, a known charge generating substance (CGM) can be used in combination as necessary. For example, phthalocyanine pigments other than gallium phthalocyanine pigments, azo pigments, perylene pigments, azulenium pigments, and the like can be used. However, a gallium phthalocyanine pigment is preferred as the main charge generating substance. However, it is preferable to use a 2,3-butanediol adduct titanyl phthalocyanine pigment at least 50% by mass or more.

(Charge transport layer)
The charge transport layer used in the photoreceptor of the present invention contains a charge transport material (CTM) and a binder resin, and is formed by dissolving and coating the charge transport material in a binder resin solution.

  Examples of charge transport materials include carbazole derivatives, oxazole derivatives, oxadiazole derivatives, thiazole derivatives, thiadiazole derivatives, triazole derivatives, imidazole derivatives, imidazolone derivatives, imidazolidine derivatives, bisimidazolidine derivatives, styryl compounds, hydrazone compounds, pyrazoline compounds Oxazolone derivatives, benzimidazole derivatives, quinazoline derivatives, benzofuran derivatives, acridine derivatives, phenazine derivatives, aminostilbene derivatives, triarylamine derivatives, phenylenediamine derivatives, stilbene derivatives, benzidine derivatives, poly-N-vinylcarbazole, poly-1- Two or more kinds of vinylpyrene, poly-9-vinylanthracene, triphenylamine derivatives and the like may be mixed and used.

  A known resin can be used as the binder resin for the charge transport layer, and polycarbonate resin, polyarylate resin, polyester resin, polystyrene resin, styrene-acrylonitrile copolymer resin, polymethacrylate resin, and styrene-methacrylic acid. Examples include ester copolymer resins, and polycarbonate is preferred. Further, BPA, BPZ, dimethyl BPA, BPA-dimethyl BPA copolymer and the like are preferable in terms of crack resistance, wear resistance, and charging characteristics.

  The charge transport layer is preferably formed by dissolving the binder resin and the charge transport material to prepare a coating solution, applying the coating solution to a certain film thickness with a coating machine, and drying the coating film.

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

  The mixing ratio of the charge transport material to the binder resin is preferably 10 to 500 parts by mass, more preferably 20 to 100 parts by mass with respect to 100 parts by mass of the binder resin.

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

  An antioxidant, an electronic conductive agent, a stabilizer and the like may be added to the charge transport layer. As the antioxidant, those described in JP-A No. 2000-305291, and as the electronic conductive agent, those described in JP-A Nos. 50-137543 and 58-76483 are preferable.

(Protective layer)
The protective layer used in the photoreceptor of the present invention is formed by applying a coating solution prepared by adding inorganic fine particles to a binder resin on a charge transport layer. The protective layer may contain an antioxidant, a lubricant and the like.

  Inorganic fine particles include silica, alumina, strontium titanate, zinc oxide, titanium oxide, tin oxide, antimony oxide, indium oxide, bismuth oxide, indium oxide doped with tin, tin oxide doped with antimony and tantalum, zirconium oxide, etc. These fine particles can be preferably used. In particular, hydrophobic silica, hydrophobic alumina, hydrophobic zirconia, fine powder sintered silica and the like whose surface has been hydrophobized are preferable.

  The number average primary particle size of the inorganic fine particles is preferably 1 to 300 nm, particularly preferably 5 to 100 nm. The number average primary particle diameter of the inorganic fine particles is magnified 10,000 times by observation with a transmission electron microscope, 300 particles are randomly observed as primary particles, and the measured value is calculated as the number average diameter of the ferret diameter by image analysis. Is the value obtained.

  The binder resin used for the protective layer may be either a thermoplastic resin or a thermosetting resin. For example, polyvinyl butyral resin, epoxy resin, polyurethane resin, phenol resin, polyester resin, alkyd resin, polycarbonate resin, silicone resin, melamine resin, and the like can be given.

  Examples of the lubricant used in the protective layer include fine resin powder (for example, fluorine resin, polyolefin resin, silicone resin, melamine resin, urea resin, acrylic resin, styrene resin), metal oxide fine powder (for example, titanium oxide). , Aluminum oxide, tin oxide, etc.), solid lubricant (eg, polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinylidene fluoride, zinc stearate, aluminum stearate, etc.), silicone oil (eg, dimethyl silicone oil, methyl) Phenyl silicone oil, methyl hydrogen polysiloxane, cyclic dimethyl polysiloxane, alkyl modified silicone oil, polyether modified silicone oil, alcohol modified silicone oil, fluorine modified silicone oil, amino modified silicone , Mercapto-modified silicone oil, epoxy-modified silicone oil, carboxyl-modified silicone oil, higher fatty acid-modified silicone oil, etc.), fluorine resin powder (for example, tetrafluoroethylene resin powder, ethylene trifluoride chloride resin powder, Hexafluoroethylene propylene resin powder, vinyl fluoride resin powder, vinylidene fluoride resin powder, fluorinated ethylene chloride resin powder and copolymers thereof, polyolefin resin powder (for example, polyethylene resin) Homopolymer resin powder such as powder, polypropylene resin powder, polybutene resin powder, polyhexene resin powder, copolymer resin powder such as ethylene-propylene copolymer, ethylene-butene copolymer, and hexene Polyolefins such as terpolymers and their thermal modifications Shifun and the like) and the like.

  The molecular weight of each resin used in the lubricant and the particle size of the powder can be selected as appropriate. The particle size is particularly preferably 0.1 μm to 10 μm. In order to disperse these lubricants uniformly, a dispersant may be added to the binder resin.

[Image forming apparatus]
Next, an image forming apparatus using the photoreceptor of the present invention will be described.

  FIG. 4 is a cross-sectional configuration diagram of a color image forming apparatus showing an embodiment of the present invention.

  In the image forming apparatus of the present invention, it is desirable to use a semiconductor laser or light emitting diode having an oscillation wavelength of 350 to 850 nm as an image exposure light source when an electrostatic latent image is formed on a photoreceptor. By using these image exposure light sources, the exposure dot diameter in the writing principal direction is narrowed down to 10 to 100 μm, and digital exposure is performed on the organic photoreceptor, so that 600 dpi (dpi: number of dots per 2.54 cm) to 2400 dpi. Or higher-resolution electrophotographic images can be obtained.

The exposure dot diameter refers to the length of the exposure beam along the main scanning direction (Ld: measured at the maximum length) in a region where the intensity of the exposure beam is 1 / e ² or more of the peak intensity.

The light beams used have a scanning optical system and LED solid scanner such as a semiconductor laser, there is a Gaussian distribution and Lorentz distribution, etc. also the light intensity distribution is in each 1 / e ² or more regions of peak intensity The exposure dot diameter according to the present invention is used.

  This color image forming apparatus is called a tandem type color image forming apparatus, and includes four sets of image forming units (image forming units) 10Y, 10M, 10C, and 10Bk, an endless belt-shaped intermediate transfer body unit 7, and a feeding unit. It comprises a paper conveying means 21 and a fixing means 24. A document image reading device SC is disposed on the upper part of the main body A of the image forming apparatus.

  The image forming unit 10Y that forms a yellow image includes a charging unit (charging step) 2Y, an exposure unit (exposure step) 3Y, and a developing unit disposed around a drum-shaped photoconductor 1Y as a first image carrier. A unit (developing step) 4Y, a primary transfer roller 5Y as a primary transfer unit (primary transfer step), and a cleaning unit 6Y. An image forming unit 10M that forms a magenta image includes a drum-shaped photosensitive member 1M as a first image carrier, a charging unit 2M, an exposure unit 3M, a developing unit 4M, a primary transfer roller 5M as a primary transfer unit, It has a cleaning means 6M. An image forming unit 10C for forming a cyan image includes a drum-shaped photoreceptor 1C as a first image carrier, a charging unit 2C, an exposure unit 3C, a developing unit 4C, and a primary transfer roller 5C as a primary transfer unit. It has cleaning means 6C. The image forming unit 10Bk that forms a black image includes a drum-shaped photoreceptor 1Bk as a first image carrier, a charging unit 2Bk, an exposure unit 3Bk, a developing unit 4Bk, a primary transfer roller 5Bk as a primary transfer unit, and a cleaning unit. 6Bk.

  The four sets of image forming units 10Y, 10M, 10C, and 10Bk include charging means 2Y, 2M, 2C, and 2Bk that rotate around the photosensitive drums 1Y, 1M, 1C, and 1Bk, and image exposure means 3Y, 3M, 3C and 3Bk, rotating developing means 4Y, 4M, 4C and 4Bk, and cleaning means 5Y, 5M, 5C and 5Bk for cleaning the photosensitive drums 1Y, 1M, 1C and 1Bk.

  The image forming units 10Y, 10M, 10C, and 10Bk have the same configuration except that the colors of toner images formed on the photoreceptors 1Y, 1M, 1C, and 1Bk are different, and the image forming unit 10Y is taken as an example in detail. explain.

  The image forming unit 10Y has a charging unit 2Y (hereinafter simply referred to as a charging unit 2Y or a charger 2Y), an exposure unit 3Y, a developing unit 4Y, and a cleaning unit 5Y (around a photosensitive drum 1Y as an image forming body). Hereinafter, the cleaning means 5Y or the cleaning blade 5Y) is simply disposed, and a yellow (Y) toner image is formed on the photosensitive drum 1Y. In the present embodiment, in the image forming unit 10Y, at least the photosensitive drum 1Y, the charging unit 2Y, the developing unit 4Y, and the cleaning unit 5Y are provided so as to be integrated.

  The charging unit 2Y is a unit that applies a uniform potential to the photosensitive drum 1Y. In the present embodiment, a corona discharge type charger 2Y is used for the photosensitive drum 1Y.

  The image exposure means 3Y performs exposure based on the image signal (yellow) on the photosensitive drum 1Y given a uniform potential by the charger 2Y, and forms an electrostatic latent image corresponding to the yellow image. As the exposure unit 3Y, a unit composed of LEDs and light-emitting elements in which light emitting elements are arranged in an array in the axial direction of the photosensitive drum 1Y, a laser optical system, or the like is used.

  The image forming apparatus of the present invention is configured by integrally combining the above-described photosensitive member and components such as a developing device and a cleaning device as a process cartridge (image forming unit), and this image forming unit is connected to the apparatus main body. It may be configured to be detachable. In addition, at least one of a charging device, an image exposure device, a developing device, a transfer or separation device, and a cleaning device is integrally supported together with a photosensitive member to form a process cartridge (image forming unit), which is detachable from the apparatus main body. A single image forming unit may be detachable using guide means such as a rail of the apparatus main body.

  The endless belt-like intermediate transfer body unit 7 includes an endless belt-like intermediate transfer body 70 as a second image carrier having a semiconductive endless belt shape that is wound around a plurality of rollers and is rotatably supported.

  Each color image formed by the image forming units 10Y, 10M, 10C, and 10Bk is sequentially transferred onto a rotating endless belt-shaped intermediate transfer body 70 by primary transfer rollers 5Y, 5M, 5C, and 5Bk as primary transfer means. Thus, a synthesized color image is formed. A transfer material P as a transfer material (a support for carrying a fixed final image: for example, plain paper, a transparent sheet, etc.) housed in the paper feed cassette 20 is fed by a paper feed means 21 and a plurality of intermediates. After passing through rollers 22A, 22B, 22C, 22D and registration roller 23, they are conveyed to a secondary transfer roller 5b as a secondary transfer means, and are secondarily transferred onto a transfer material P to transfer a color image all at once. The transfer material P onto which the color image has been transferred is subjected to fixing processing by the fixing unit 24, is sandwiched between paper discharge rollers 25, and is placed on a paper discharge tray 26 outside the apparatus. Here, a transfer support for a toner image formed on a photosensitive member such as an intermediate transfer member or a transfer material is collectively referred to as a transfer medium.

  On the other hand, after the color image is transferred to the transfer material P by the secondary transfer roller 5b as the secondary transfer means, the residual toner is removed by the cleaning means 6b from the endless belt-shaped intermediate transfer body 70 in which the transfer material P is separated by curvature. The

  During the image forming process, the primary transfer roller 5Bk is always in contact with the photoreceptor 1Bk. The other primary transfer rollers 5Y, 5M, and 5C are in contact with the corresponding photoreceptors 1Y, 1M, and 1C, respectively, only during color image formation.

  The secondary transfer roller 5b contacts the endless belt-shaped intermediate transfer body 70 only when the transfer material P passes through the secondary transfer roller 5b.

  Further, the housing 8 can be pulled out from the apparatus main body A through the support rails 82L and 82R.

  The housing 8 includes image forming units 10Y, 10M, 10C, and 10Bk and an endless belt-shaped intermediate transfer body unit 7.

  The image forming units 10Y, 10M, 10C, and 10Bk are arranged in tandem in the vertical direction. An endless belt-shaped intermediate transfer body unit 7 is disposed on the left side of the photoreceptors 1Y, 1M, 1C, and 1Bk in the drawing. The endless belt-shaped intermediate transfer body unit 7 includes an endless belt-shaped intermediate transfer body 70 that can be rotated by winding rollers 71, 72, 73, 74, primary transfer rollers 5Y, 5M, 5C, 5Bk, and cleaning means 6b. Consists of.

  The image forming apparatus of the present invention is generally applicable to electrophotographic apparatuses such as electrophotographic copying machines, laser printers, LED printers, and liquid crystal shutter printers. The present invention can be widely applied to such devices.

  Next, representative embodiments of the present invention will be shown and the present invention will be further described. However, it is needless to say that the embodiments of the present invention are not limited thereto.

  In the text, “part” means “part by mass”.

Synthesis example 1
(Synthesis of amorphous titanyl phthalocyanine)
1,3-diiminoisoindoline; 29.2 g was dispersed in 200 ml of orthodichlorobenzene, titanium tetra-n-butoxide; 20.4 g was added, and the mixture was heated at 150 to 160 ° C. for 5 hours in a nitrogen atmosphere. After allowing to cool, the precipitated crystals were filtered, washed with chloroform, washed with 2% aqueous hydrochloric acid, washed with water, washed with methanol, and dried to obtain 26.2 g (yield 91%) of crude titanyl phthalocyanine. Next, the crude titanyl phthalocyanine was dissolved by stirring in 250 ml of concentrated sulfuric acid at 5 ° C. or lower for 1 hour, and this was poured into 5 L of water at 20 ° C. The precipitated crystals were filtered and sufficiently washed with water to obtain 225 g of a wet paste product. The wet paste product was then frozen in a freezer, thawed again, filtered and dried to obtain 24.8 g of amorphous titanyl phthalocyanine (yield 86%).

(Synthesis of pigment (CG-1) of the present invention)
Orthochlorobenzene (ODB) was prepared by adding 10.0 g of the above-mentioned amorphous titanyl phthalocyanine and 0.94 g (0.6 equivalent ratio) of (2R, 3R) -2,3-butanediol (equivalent ratio is equivalent to titanyl phthalocyanine, hereinafter the same). ) The mixture was mixed in 200 ml and stirred at 60 to 70 ° C. for 6.0 hours. After standing overnight, methanol was added to the reaction solution, and the resulting crystals were filtered. The crystals after filtration were washed with methanol (a pigment containing (2R, 3R) -2,3-butanediol adduct titanyl phthalocyanine). CG-1: 10.3 g was obtained. The X-ray diffraction spectrum of CG-1 is shown in FIG. There are distinct peaks at 8.3 °, 24.7 °, 25.1 ° and 26.5 °. There is a peak in the 576 and 648 in the mass spectra, O-Ti-O both absorption appears Ti = O near 970 cm ^-1, around 630 cm ^-1 in the IR spectrum. In addition, since thermal analysis (TG) has a mass loss of about 7% at 390 to 410 ° C., a 1: 1 adduct of titanyl phthalocyanine and (2R, 3R) -2,3-butanediol (shown in Chemical Formula 1 above) A dehydrated condensation structure) and a non-adduct (not added) titanyl phthalocyanine mixed crystal.

It was 31.2 m < ² > / g when the BET specific surface area of the obtained CG-1 was measured with the flow type specific surface area automatic measuring device (Micrometrics flow soap type: Shimadzu Corporation).

Synthesis Example 2 (Synthesis of pigment (CG-2) of the present invention)
(2S, 3S) -2,3 in the same manner as in Synthesis Example 1 except that (2S, 3S) -2,3-butanediol was used instead of (2R, 3R) -2,3-butanediol. -Pigment CG-2 containing butanediol-titanyl phthalocyanine adduct was obtained: 10.5 g. In the X-ray diffraction spectrum of CG-2, clear peaks are observed at 8.3 °, 24.7 °, 25.1 °, and 26.5 °, and in the IR spectrum, Ti = O around 970 cm ⁻¹ , 630 cm. Both absorptions of O—Ti—O appear in the vicinity of ⁻¹ . The BET specific surface area of CG-2 is 30.5 m ² Synthesis Example 3 (Synthesis of Pigment (CG-3) of the Present Invention)
In the reaction of amorphous titanyl phthalocyanine of Synthesis Example 1 and (2R, 3R) -2,3-butanediol, the reaction temperature was changed to 90 to 100 ° C. instead of 60 to 70 ° C. (2R , 3R) -2,3-butanediol adduct, pigment CG-3 containing titanyl phthalocyanine: 10.6 g was obtained. In the X-ray diffraction spectrum of CG-3, clear peaks are observed at 8.3 °, 24.7 °, 25.1 °, and 26.5 °, and in the IR spectrum, Ti = O around 970 cm ⁻¹ , 630 cm. Both absorptions of O—Ti—O appear in the vicinity of ⁻¹ . The BET specific surface area of CG-3 was 20.5 m ² / g.

Synthesis Example 4 (Synthesis of pigment (CG-4) of the present invention)
In the reaction of the amorphous titanyl phthalocyanine of Synthesis Example 1 and (2R, 3R) -2,3-butanediol, the reaction temperature was changed to 130 to 140 ° C. instead of 60 to 70 ° C. (2R , 3R) -2,3-butanediol adduct titanyl phthalocyanine pigment CG-4: 10.6 g was obtained. In the X-ray diffraction spectrum of CG-4, clear peaks are observed at 8.3 °, 24.7 °, 25.1 °, and 26.5 °, and in the IR spectrum, Ti = O around 970 cm ⁻¹ , 630 cm. Both absorptions of O—Ti—O appear in the vicinity of ⁻¹ . The BET specific surface area of CG-4 was 13.5 m ² / g.

Synthesis Example 5 (Synthesis of pigment (CG-5) of the present invention)
In the reaction of amorphous titanyl phthalocyanine of Synthesis Example 1 with (2R, 3R) -2,3-butanediol, (2R, 3R) -2,3-butanediol is converted into a racemic 2,3- Pigment CG-5: 11.5 g containing (racemic) -2,3-butanediol adduct titanyl phthalocyanine was obtained in the same manner except that butanediol was used. Appear both absorption of O-Ti-O Ti = O near 970 cm ^-1, around 630 cm ^-1 in the IR spectrum of CG-5, BET specific surface area was 28.6m ² / g.

Synthesis Example 6 (Synthesis of Pigment (CG-6) of Comparative Example)
In the reaction of amorphous titanyl phthalocyanine of Synthesis Example 1 and (2R, 3R) -2,3-butanediol, 2.35 g (1.5 equivalent ratio) of (2R, 3R) -2,3-butanediol was used, Except that the reaction temperature was 130 to 140 ° C., 12.0 g of pigment CG-6 containing (2R, 3R) -2,3-butanediol adduct titanyl phthalocyanine was obtained. In the X-ray diffraction spectrum of CG-6 (FIG. 7 (1)), clear peaks are observed at 9.5 °, 16.4 °, 19.1 °, 24.7 °, 26.5 °, and IR disappeared Ti = O absorption near 970 cm ^-1 in the spectrum, the absorption of O-Ti-O appears in the vicinity of 630 cm ^-1. The BET specific surface area of CG-6 was 10.2 m ² / g.

<Preparation of Photoreceptor 1>
<Preparation of substrate 1>
An aluminum alloy element tube having a length of 362 was mounted on an NC lathe, and the following cutting program was set with a diamond sintered tool to perform cutting. A cylindrical substrate having an outer diameter of 59.95 mm and a surface Rz of 0.75 μm was obtained.

  The spindle speed at this time was 3000 rpm, and the reciprocations of 0.300 and 0.315 mm / rev were repeated from the start, and the section lengths were 0.5 mm, 1.6 mm, 2.8 mm, 1.1 mm and 2. It was performed by setting to repeat six sections with the speed switched at 5 mm and 3.2 mm as one cycle. At this time, ΔL of the raw tube was 50 μm.

  ΔL uses surfcom 1400D manufactured by Tokyo Seimitsu Co., Ltd., and measures JIS'01 standard, roughness measurement, measurement length 4.0 mm, cut-off 0.8 mm (Gaussian), measurement speed 0.3 mm / sec. It is the difference between the maximum value and the minimum value of the cutting cycle read from the measured cross-section curve obtained near the center.

(Formation of intermediate layer)
1 part by weight of binder resin (N-1) is added to 20 parts by weight of ethanol / n-propyl alcohol / tetrahydrofuran (45:20:35 volume ratio), dissolved with stirring, and then surfaced with 5% by weight of methyl hydrogen polysiloxane. 4.2 parts by mass of the treated rutile titanium oxide particles were mixed, and the mixed solution was dispersed using a bead mill. At this time, an average particle size of 0.1 to 0.5 mm was used and dispersed at a filling rate of 80%, a peripheral speed setting of 4 m / sec, and a mill residence time of 3 hours to prepare an intermediate layer coating solution. After the same solution was filtered through a 5 μm filter, the intermediate layer coating solution was applied to the outer periphery after washing the “substrate 1” prepared above by a dip coating method to form an “intermediate layer” having a dry film thickness of 2 μm. .

<Charge generation layer coating solution>
The following composition was mixed and dispersed with a circulating ultrasonic homogenizer RUS-600TCVP (manufactured by Nippon Seiki Seisakusho, 19.5 kHz, 600 W) (abbreviation: circulating homogenizer) at a circulating flow rate of 40 L / H for 0.5 hour. The charge generation layer coating solution thus prepared was applied onto the intermediate layer by a dip coating method to form a “charge generation layer” having a dry film thickness of 0.5 μm.

Charge generation material: CG-1 of Synthesis Example 1 24 parts Polyvinyl butyral resin “ESREC BL-1” (manufactured by Sekisui Chemical Co., Ltd.) 12 parts 3-methyl-2-butanone / cyclohexanone = 4/1 (V / V) 400 parts A charge transport layer coating solution having the following composition mixed thereon was applied and dried by heating at 110 ° C. for 60 minutes to form a charge transport layer having a film thickness of 20 μm.

<Charge transport layer coating solution>
Charge transport material: (Compound A below) 200 parts Polycarbonate “Iupilon Z300” (manufactured by Mitsubishi Gas Chemical Company) 300 parts 2,6-di-tert-butyl-4-phenylphenol 5 parts Toluene / tetrahydrofuran = 1/9 (v / V) 2000 copies

  The charge generation layer is dried on an aluminum support, coated and dried at a film thickness of 0.3 μm, a sample for reflection spectrum measurement is prepared, and an optical film thickness measurement device Solid Lambda Thickness (Spectra Corp.) is used. The reflection spectrum was measured. The measured data is shown in FIG. The reflection spectrum was measured as a relative reflectance when the reflectance of the aluminum support was 100%. In order to remove irregularities due to interference fringes in the obtained reflection spectrum, the measurement data is approximated by a second order polynomial in the range of 685 to 715 nm and 765 to 795 nm, and the reflectance (R700) and reflectance (R780) are calculated. The ratio (R700 / R780) was calculated.

  Further, FIG. 7B shows data obtained by measuring an X-ray diffraction spectrum using a sample obtained by coating and drying the charge generation layer on a transparent glass plate.

Production of Photoreceptor 2 Photoreceptor 2 was produced in the same manner as in Photoreceptor 1 except that the dispersion time of the charge generation material coating solution was changed to 2.5 hours.

Production of Photoreceptor 3 Photoreceptor 3 was produced in the same manner as in Photoreceptor 1 except that CG-2 obtained in Synthesis Example 2 was used as the charge generation material.

Production of Photoreceptor 4 Photoreceptor 4 was produced in the same manner as in Photoreceptor 1 except that the charge generation layer coating solution was changed to ultrasonic dispersion under the following conditions.

<Charge generation layer coating solution>
The following compositions were mixed and subjected to ultrasonic dispersion for 1.5 hours in an ultrasonic cleaning tank (abbreviation: US bath) of 28 kHz and 500 W.

Charge generation material: CG-1 of Synthesis Example 1 24 parts Polyvinyl butyral resin “ESREC BL-1” (manufactured by Sekisui Chemical Co., Ltd.) 12 parts 3-methyl-2-butanone / cyclohexanone = 4/1 (V / V) 400 parts Production of Photoreceptor 5 Photoreceptor 5 was produced in the same manner as in Photoreceptor 4, except that the dispersion time of the charge generation material coating solution was changed to 4 hours.

Production of Photoreceptor 6 Photoreceptor 6 was produced in the same manner as in Photoreceptor 1 except that the charge generation layer coating solution was changed to sand mill (abbreviation: SM) dispersion under the following conditions.

<Charge generation layer coating solution>
The following compositions were mixed, and glass beads having an outer diameter of 1 mm were used as a dispersion medium, and dispersion was performed for 1 hour in a sand mill under conditions of a bead filling rate of 80% by volume and a rotation speed of 800 rpm.

Charge generation material: CG-1 of Synthesis Example 1 24 parts Polyvinyl butyral resin “ESREC BL-1” (manufactured by Sekisui Chemical Co., Ltd.) 12 parts 3-methyl-2-butanone / cyclohexanone = 4/1 (V / V) 400 parts Production of Photoreceptor 7 Photoreceptor 7 was produced in the same manner as in Photoreceptor 6, except that CG-3 obtained in Synthesis Example 3 was used as the charge generation material.

Production of Photoreceptor 8 Photoreceptor 8 was produced in the same manner as in Photoreceptor 6, except that CG-4 obtained in Synthesis Example 4 was used as the charge generation material.

Production of Photoreceptor 9 Photoreceptor 9 was produced in the same manner as in Photoreceptor 1 except that CG-5 obtained in Synthesis Example 5 was used as the charge generation material.

Production of Photoreceptor 10 (Comparative Example) Photoreceptor 10 was produced in the same manner as in Photoreceptor 6, except that the dispersion time of the charge generation layer coating solution was changed to 10 hours.

Production of Photoreceptor 11 (Comparative Example) Photoreceptor 11 was produced in the same manner as Photoreceptor 1 except that CG-4 obtained in Synthesis Example 4 was used as the charge generation material.

Production of Photoreceptor 12 (Comparative Example) Photoreceptor 12 was produced in the same manner as Photoreceptor 6, except that CG-6 obtained in Synthesis Example 6 was used as the charge generation material.

  For the photoconductors 2 to 12, the reflection spectrum was measured in the same manner as the photoconductor 1. The results are shown in Table 2. The values of the reflection spectrum in Table 1 are values measured in the charge generation layer, but almost the same values are obtained even if the charge transport layer is measured after coating.

Production of Photoreceptor 13 In production of the photoreceptor 1, a photoreceptor 13 using a raw tube (substrate 2) having a spindle rotation speed of 2000 rpm and ΔL of 30 μm was obtained.

Production of Photoreceptor 14 In production of the photoreceptor 1, a photoreceptor 14 using a raw tube (substrate 3) having a spindle rotation speed of 750 rpm and ΔL of 10 μm was obtained.

Production of Photoreceptor 15 In production of the photoreceptor 1, a photoreceptor 15 using a raw tube (substrate 4) with a spindle rotation speed of 7000 rpm and ΔL of 70 μm was obtained.

Production of Photoreceptor 16 In production of the photoreceptor 1, a photoreceptor 16 using a raw tube (substrate 5) with a spindle rotation speed of 6000 rpm and ΔL of 60 μm was obtained.

Photoconductor 17
In the production of the photoconductor 1, a photoconductor 17 using a raw tube (substrate 6) having a spindle rotation speed of 10,000 rpm and a ΔL of 100 μm was obtained.

Production of Example 18 In production of the photosensitive member 1, cutting was performed by changing the feed rate of the cutting tool between 0.550 mm and 0.352 mm / rev every 0.5 mm, and ΔL was 7 μm (tube 7). Thus, a photoreceptor 18 was obtained.

Production of photoconductor 19 In production of the photoconductor 17, the feeding speed of the cutting tool was changed from 0.340 to 0.360 mm / rev to 0.350 to 0.380 mm / rev, and every 1.5 mm. A photosensitive member 19 using a base tube (substrate 8) having a ΔL of 200 μm was obtained by a program that repeatedly increased and decreased by 0.005 mm.

  In the production of the photoconductor 1, a photoconductor 19 was obtained using a base tube (substrate 8) having a spindle rotation speed of 11000 rpm and a ΔL of 110 μm.

Production of photoconductors 20 to 22 Photoconductors 20 to 22 were produced in the same manner as in production of photoconductor 1, except that the charge layer material of the charge transport layer was changed from CTM-A to CTM-B, C, and D. .

  The photoreceptors 1 to 22 are summarized in Table 1 below.

In Table 1,
Mixed crystal (R, R form) is a pigment containing titanyl phthalocyanine and (2R, 3R) -2,3-butanediol titanyl phthalocyanine adduct. Mixed crystal (S, S form) is titanyl phthalocyanine and (2S , 3S) -2,3-Butanediol titanyl phthalocyanine adduct A mixed crystal (racemic) is a pigment containing titanyl phthalocyanine and (racemic) -2,3-butanediol titanyl phthalocyanine adduct The simple substance means a pigment * 1 containing only the (2R, 3R) -2,3-butanediol titanyl phthalocyanine adduct represents a BET specific surface area (m ² / g).

  * 2 represents the ratio (R700 / R780) of the reflectance (R700) at 700 nm and the reflectance (R780) at 780 nm of the reflection spectrum of the charge generation layer.

(Performance evaluation)
(An oblique stripe due to interference)
The performance evaluation basically uses the bizhub PRO C6501 manufactured by Konica Minolta Business Technologies, Inc. having the configuration of FIG. 4, and the exposure pattern of the explanatory diagram illustrating the halftone exposure pattern of FIG. 5 at the black (Bk) position. Half output at low temperature and low humidity (10 ° C., 20% RH) using A (FIG. 5) and exposure pattern B (FIG. 5) and “POD gloss coat (100 g / m ² )” manufactured by Oji Paper Co., Ltd. The evaluation was performed by visual evaluation of the tone image.

  Table 2 shows the results of evaluation based on the following criteria.

◎: Diagonal streak is not seen at all ○: Diagonal streak is seen slightly, but there is no problem in actual use ×: Diagonal streak is seen, there is a problem in actual use (gradation)
Under the above temperature and humidity conditions, an original image having 60 gradation steps was copied from a white image to a black solid image, and the gradation property was evaluated. The evaluation was performed by visually evaluating an image of gradation steps under sufficient daylight conditions, and evaluating the total number of gradation steps with significance.

A: Gradation is 21 steps or more (good)
A: 12 to 20 steps in gradation (no problem in practical use)
Δ: Step difference in gradation is 8 to 11 (re-examination of practicality is necessary: There is practicality in image quality where gradation is not important)
X: The gradation is 7 steps or less (there is a problem in practical use)
(Black pot)
After printing 200,000 A4 images of YMCBk color printing ratio 2.5% on neutral paper (20 ° C, 50% RH) on neutral paper, the grid charge voltage of the scorotron charger is -1000V, and the development bias of reverse development is A continuous image copy of 10,000 A4 paper was performed in a high temperature and high humidity environment (HH: 35 ° C., 85 RH%) at a setting of −800 V, and the presence or absence of black spot image defects at the start and end was confirmed.
◎: Black spot image defect not found ○: Mild black spot (6 or less on A4 paper) occurred at the end, but no problem in practical use ×: Black spot occurred from the beginning, and black spot occurred at the end Increase.

(2 dot lines)
Under the above temperature and humidity conditions, a 2-dot white line was produced in a solid black image and evaluated according to the following criteria.

A: A white line of 2 dot lines is reproduced continuously, and the solid image density is 1.2 or more (good).
○: The white line of 2 dot lines is reproduced continuously, but the solid image density is less than 1.2 to 1.0 or more (no problem in practical use)
×: The white line of the 2-dot line is cut and reproduced, or the white line of the 2-dot line is reproduced continuously, but the solid image density is less than 1.0 (there is a problem in practical use)
The above-mentioned solid image density is measured using RD-918 manufactured by Macbeth. The relative reflection density was measured with the paper reflection density set to “0”.

  In Table 2, * 3 represents an oblique stripe due to interference.

  As apparent from the performance evaluation results shown in Table 2, the charge generation layer satisfies the condition of 10 μm ≦ ΔL and the charge generation layer uses the 2,3-butanediol adduct titanyl phthalocyanine pigment according to the present invention, and the reflection of the charge generation layer Photoreceptors 1 to 9, 13 to 17, and 19 to 22 having a ratio (R700 / R780) of reflectance (R700) at 700 nm and reflectance (R780) at 780 nm of the spectrum of 0.8 to 1.3 are used. However, the ratio of the photoconductors 10 to 12 (R700 / R780) is less than 0.8 or greater than 1.3, or ΔL is 7 μm. The photoreceptor 18 is evaluated to have a problem in practicality in any of the evaluation items.

1Y, 1M, 1C, 1Bk photoconductor 2Y, 2M, 2C, 2Bk charging unit 3Y, 3M, 3C, 3Bk exposure unit 4Y, 4M, 4C, 4Bk developing unit 10Y, 10M, 10C, 10Bk image forming unit

Claims (3)

In an organic photoreceptor having at least a charge generation layer and a charge transport layer on a cylindrical substrate, the cylindrical substrate has a concavo-convex shape formed on the outer peripheral surface along the central axis, and processing the concavo-convex shape Reflection at 700 nm of the reflection spectrum of the charge generation layer, wherein the difference in period (ΔL) satisfies Equation 1 and the charge generation layer comprises a pigment containing titanyl phthalocyanine and 2,3-butanediol adduct titanyl phthalocyanine An organic photoreceptor, wherein the ratio (R700 / R780) of the ratio (R700) to the reflectance (R780) at 780 nm is 0.8 to 1.3.
However, the reflectance is a reflectance measured by forming the charge generation layer on the aluminum support, and is a relative reflectance when the reflectance of the aluminum support is 100%.
Formula 1 10μm ≦ ΔL
(However, ΔL is the difference in the machining cycle in the central axis direction within the image area of the cylindrical substrate.)   2. The organophotoreceptor according to claim 1, wherein the pigment has a peak at least at 8.3 ° in a Bragg angle (2θ ± 0.2 °) in an X-ray diffraction spectrum.   The organic photoreceptor according to claim 1 or 2, means for forming an electrostatic latent image on the organic photoreceptor, means for developing the electrostatic latent image with toner, means for transferring the formed toner image to an image support An image forming apparatus comprising at least means for fixing the toner image after transfer.

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