JP2004126560A - Electrophotographic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic device which provides high fineness, can deal with a higher speed, outputs stable images without thicken letters in spite of repetitive use at a high speed, and maintains the high sensitivity intrinsic to titanyl phthalocyanine even when a non-halogen system solvent is used for a coating liquid for a charge transporting layer. <P>SOLUTION: The electrophotographic system includes at least an electrostatic charging means, an exposure means, a developing means, a transfer means, and an electrophotographic photoreceptor, in which the time from the exposure means to the developing means is ≤200 msec. The exposure energy when the photoreceptor is irradiated writing light having resolution ≥600 dpi from the exposure means is ≤5 erg/cm<SP>2</SP>on the surface of the photoreceptor and the electrophotographic photoreceptor contains a titanyl phthalocyanine crystal that the diffraction peak of a Bragg angle 2θ with CuKα line has the maximum diffraction peak at least at 27.2° and further has the major peaks at 9.4°, 9.6° and 24.0° in its charge generating layer. <P>COPYRIGHT: (C)2004,JPO

Description

{Circle over (2)} The present invention relates to an electrophotographic apparatus using an electrophotographic photosensitive member in which image light is written by irradiation of a specific amount of light or less and at least a charge generation layer containing a specific titanyl phthalocyanine crystal and a charge transport layer are sequentially laminated.

In recent years, the development of information processing system machines using electrophotography has been remarkable. In particular, an optical printer that converts information into a digital signal and records information by light has remarkably improved in print quality and reliability. This digital recording technology is applied not only to printers but also to ordinary copying machines, and so-called digital copying machines have been developed. In addition, a copier equipped with the digital recording technology in a conventional analog copy is expected to have a further increasing demand in the future because various information processing functions are added. Further, with the spread of personal computers and improvement in performance, the progress of digital color printers for outputting images and documents in color has been rapidly progressing.

高 In such a digital electrophotographic apparatus, a high-output light source such as an LD or an LED is used as a writing light source. Although such a light source certainly enables a high output, both the output and the life of the element, and the output and the stability are contradictory. Therefore, with respect to the longevity and stability of the element in repeated use in an electrophotographic apparatus, it is desired to use the element with the lowest possible output.

In recent years, there has been a demand for miniaturization and high-speed of the apparatus at the same time. Regarding the miniaturization of the apparatus, the A3 size is the smallest size that can be output, and the diameter of the photoconductor is reduced accordingly. In a monochrome electrophotographic apparatus, since only one photoconductor is used, a photoconductor having a diameter of about 100 mm at the maximum is used. On the other hand, among full-color electrophotographic apparatuses, tandem-type full-color electrophotographic apparatuses aiming at high-speed printing are mainly used. In a tandem type full-color electrophotographic apparatus, since a plurality of image forming elements are mounted, it is necessary to further reduce the diameter of the photoconductor. In most cases, a photoconductor having a diameter of 30 mm is used.
In increasing the speed of a monochrome electrophotographic apparatus, a copying (printing) speed of 60 sheets / min or more (maximum 100 sheets / min) has become the norm. In addition, the minimum members required for the electrophotographic process (charging, exposure, development, transfer, cleaning and neutralization as necessary) are arranged around the photoreceptor, and other members are also used for high durability. In some cases, the space around the photoreceptor is very narrow. For this reason, even if a photoreceptor having a diameter of 100 mm is used as described above, the distance between exposure and development cannot be too long, and the linear speed of the photoreceptor is extremely high. Is getting shorter and shorter. In terms of time, even if it can be set longer, it is at most about 200 msec.
On the other hand, in a tandem type full-color electrophotographic apparatus, a small-diameter photosensitive member is used as described above, and a copy (print) speed of 30 sheets / min or more has been developed. Under such circumstances, even if the area around the photoconductor is simplified as much as possible, the time between exposure and development can be set to be equal to or less than that of a monochrome electrophotographic apparatus.
In the future, it is thought that further speeding up will be promoted by dealing with business documents and the like, and achieving this high-speed response (sufficient light attenuation and carrier movement) in a short time is a key.
To cope with this, at least a high gain (larger potential decay) and a high response (faster potential decay) of the photoconductor are required. The former is entrusted to the development of charge generating substances having high quantum efficiency, and the latter is entrusted to the development of charge transport substances having high mobility.
Since a charge generating substance having a high quantum efficiency is generally a compound having high chemical reactivity, there are many materials whose properties are poor in stability due to repeated use in an electrophotographic apparatus.

On the other hand, regarding the improvement of the mobility, the development of a low-molecular charge transport material exhibiting high transport characteristics and the development of a molecular dispersion polymer have led to the use of a low-molecular charge transport material at a somewhat high concentration to achieve 10 ⁻⁵ (cm ^2). / V · sec) The mobility in the first half of the order can be obtained. Unless the thickness of the charge transport layer is extremely large, the time from the writing section to the developing section can be reduced to less than 100 msec when considering the mobility. Has also become available. However, it is an undeniable fact that writing using an LD or LED shows reciprocity failure in carrier generation of the photoconductor. This is not because the charge generating material has a sufficiently high photocarrier efficiency, but because the photoreceptor is irradiated with an excessive amount of light, the photogenerated material in the photoexcited state returns to the ground state before becoming a photocarrier. This is because carrier recombination occurs before injection of carriers into the charge transport layer despite deactivation or generation of photocarriers.

In fact, it is not impossible to increase the apparent gain (potential decay) of a photoconductor by irradiating a photoconductor with a low quantum efficiency with a larger amount of light. However, under such conditions, when a predetermined dot or line is written, a phenomenon of so-called character thickening such that the dot becomes large or the line becomes thick occurs. Such a phenomenon has not been remarkable in an electrophotographic process in which the resolution is less than 600 dpi, but since the resolution can be improved by reducing the writing beam diameter as in recent years. , The problem has become very prominent. Actually, the electrophotographic apparatus to which the present invention is applied is an apparatus having a resolution of writing light of 600 dpi or more.

In view of the above facts, it is important to suppress (decrease) the output from the element in the electrophotographic apparatus as much as possible in order to prevent the deterioration and instability of the writing element. This also has the effect of faithfully reproducing minute dots. However, among the charge generation materials developed so far, materials that exhibit high gain in a short time of 200 msec or less as the time between exposure and development and stably exhibit this function even when used repeatedly are extremely rare. there were. For this reason, in an electrophotographic apparatus in which the time between exposure and development is 200 msec or less, it has been extremely difficult to reduce the exposure energy of the irradiation light to the photoreceptor (5 erg / cm ² or less).

The only material capable of expressing such a high gain is a titanyl having a maximum diffraction peak at least at 27.2 ° as a diffraction peak (± 0.2 °) at a Bragg angle of 2θ with respect to CuKα radiation (wavelength: 1.542 °). Phthalocyanine crystals are known. However, this crystal type has a problem that the stability as a crystal is low, and the crystal easily transitions to a crystal having a maximum diffraction peak at 26.2 ° against mechanical stress such as dispersion and thermal stress. Therefore, the crystal form after the crystal transition is much lower in sensitivity than this crystal form, and when a part of the crystal undergoes a crystal transition, a sufficient photocarrier generation function cannot be exhibited. In addition, there is also a problem that the chargeability tends to decrease when the photoreceptor is repeatedly used.

In order to solve such a problem, the layout of the electrophotographic apparatus is changed to increase the distance between exposure and development, to reduce the linear velocity of the photoconductor, or to increase the diameter of the photoconductor. Is possible. However, the first method requires a large design change of the machine, which is not practical. In the second method, the copying (printing) speed is reduced, and high-speed operation cannot be performed. In the third method, the size of the device itself becomes large, deviating from the mainstream high speed and small size.
From the above, as a diffraction peak (± 0.2 °) at a Bragg angle of 2θ, a special crystal type is used among titanyl phthalocyanine crystals having a maximum diffraction peak at least at 27.2 ° so that exposure can be performed at high speed. It has been found that the above problems can be solved by laying out the inter-development time at 200 msec or less and using the exposure energy applied to the photoreceptor surface at 5 erg / cm ² or less.

On the other hand, a crystal having a maximum diffraction peak at 26.2% is stable as a crystal, has little environmental fluctuation in photoreceptor characteristics such as photosensitivity, and has good charge stability when repeatedly used. When the crystal having the maximum diffraction peak at 26.2 ° is mixed in a large amount with respect to the crystal having the maximum diffraction peak at 27.2 °, the adverse effect on the photoreceptor characteristics is large, but the specific amount is small. In some cases, there is a case where environmental stability or chargeability in repeated use can be stabilized.

The charge transport layer that performs the charge transport function is mainly composed of the charge transport substance and the binder resin as described above, and is generally formed by applying a coating solution in which these materials are dissolved or dispersed in a solvent. is there. As the solvent, halogen-based solvents such as dichloromethane and chloroform are mainly used because they exhibit excellent properties in solubility and coatability.

In recent years, awareness of environmental issues has increased, and the development of a photoreceptor using a non-halogen solvent having a small impact on the human body and the environment has been desired. However, when a photoreceptor is manufactured using the coating solution for a charge transport layer using a non-halogen solvent, there is a problem that the light attenuation characteristic in a low electric field is reduced and the residual potential is increased. In particular, the Bragg angle 2θ with respect to a specific crystal type (CuKα ray (wavelength 1.542 °)) exhibiting a rare high sensitivity in a wavelength range (600 to 780 nm) where a relatively stable oscillation output of an LD or LED can be obtained at present. This phenomenon is remarkable in titanyl phthalocyanine having a maximum diffraction peak at least at 27.2 ° as a diffraction peak (± 0.2 °), and this phenomenon is remarkable. No, it is a big problem.

Various studies have also been made on a method using a non-halogen solvent, and for example, a method using a dioxolane compound as a solvent as a halogen-free organic solvent has been proposed (for example, see Patent Document 1). .
Further, a method using tetrahydrofuran (for example, see Patent Document 2) and a method of adding a specific antioxidant or an ultraviolet absorber to a cyclic ether solvent (for example, see Patent Document 3) have been proposed.
However, even when these methods are used, there have been problems such as an insufficient effect on the above-mentioned defects, or a deterioration in sensitivity characteristics due to the influence of additives.
Therefore, even when a non-halogen solvent is used for the charge transport layer coating liquid, an electrophotographic photoreceptor that exhibits good light attenuation characteristics using titanyl phthalocyanine having a specific high sensitivity as a charge generating substance, It has been desired to complete the used electrophotographic apparatus and the process cartridge for electrophotography.

JP-A-10-326023 (Claims 1, 2, and 5) JP 2001-356506 A (Claims on page 2, column 1, line 1 to page 3, column 3, line 6) JP-A-4-191745 (Claims on page 1, lower left column, fourth line to lower right column, eighth line)

SUMMARY OF THE INVENTION It is an object of the present invention to provide an electrophotographic apparatus capable of supporting high definition and high speed and outputting a stable image without thickening of characters even when repeatedly used at high speed.
Specifically, an electrophotographic apparatus that eliminates deterioration and instability of a light source and has high stability of the surface potential (exposed portion and unexposed portion) of a photoreceptor even when writing is performed at a resolution of 600 dpi or more. To provide. Another object of the present invention is to provide an electrophotographic apparatus which maintains the high sensitivity inherent in titanyl phthalocyanine even when a non-halogen solvent is used in the coating solution for the charge transport layer.

The present inventors have intensively studied the use of a high-speed digital electrophotographic apparatus in consideration of the reliability of a light source and the setting of an optimal photoconductor corresponding thereto, and have completed the present invention.
That is, the object of the present invention is to provide (1) an electronic device comprising at least a charging unit, an exposing unit, a developing unit, a transferring unit, and an electrophotographic photosensitive member, wherein the time from the exposing unit to the developing unit is 200 msec or less A photographic apparatus, wherein the exposure energy when irradiating the photosensitive member with writing light having a resolution of 600 dpi or more from the exposure means is 5 erg / cm ² or less on the surface of the photosensitive member, and the electrophotographic photosensitive member is a conductive support. An electrophotographic photoreceptor comprising at least a charge generation layer and a charge transport layer laminated in this order on the electrophotographic photoreceptor. ), Has a maximum diffraction peak at least at 27.2 °, further has major peaks at 9.4 °, 9.6 °, and 24.0 °, and has the lowest diffraction peak. A titanyl phthalocyanine crystal having a peak at 7.3 °, having no peak between the peak at 7.3 ° and the peak at 9.4 °, and further having a peak at 26.3 °. Characteristic Electrophotographic Apparatus ", (2)" In the titanyl phthalocyanine crystal, the peak intensity at 26.3 ° is in the range of 0.1 to 5% with respect to the peak intensity at the maximum diffraction peak of 27.2 °. (3) The electrophotographic apparatus according to the above (1), which is a titanyl phthalocyanine crystal, wherein the titanyl phthalocyanine crystal has an average primary particle size of less than 0.3 μm. (4) The electrophotographic photoreceptor has a volume average particle size of the titanyl phthalocyanine crystal particles of 0.3 μm or less. Standard deviation (1) wherein the dispersion is obtained by dispersing the particles until the particle diameter becomes equal to or less than 2 μm, and then applying the charge generation layer using a dispersion liquid filtered through a filter having an effective pore diameter of 3 μm or less. (5) "The titanyl phthalocyanine crystal has a diffraction peak (± 0.2 °) at a Bragg angle 2θ of at least 7.0 with respect to CuKα characteristic X-rays (wavelength 1.542 °). Amorphous titanyl phthalocyanine or low crystalline titanyl phthalocyanine having an average primary particle size of 0.1 μm or less having a maximum diffraction peak at ~ 7.5 ° and a half width of the diffraction peak of 1 ° or more is present in the presence of water Under an organic solvent, the crystal conversion is performed, and before the average size of the primary particles after the crystal conversion grows to 0.3 μm or more, titanyl phthalocyanate after the crystal conversion from the organic solvent is used. (9) The electrophotographic apparatus according to the above (3), wherein nin is separated and filtered, and (6) the charge transport layer has at least a triarylamine structure in the main chain and / or side. The electrophotographic apparatus according to any one of the above items (1) to (5), comprising a polycarbonate contained in a chain ”, (7)“ having a protective layer on the charge transport layer ”. wherein wherein the first (1) electrophotographic apparatus according to any one of claim to the (6) term "(8)" the protective layer resistivity ¹⁰ 10 Ω · cm or more inorganic pigments or metal oxide And (9) that the charge transport layer of the photoreceptor is formed using a non-halogen solvent. The electron according to any one of the above items (1) to (8). (10) The electrophotographic apparatus according to the above (9), wherein the non-halogen solvent is at least one selected from cyclic ethers and aromatic hydrocarbons. (11) The method according to any one of the above items (1) to (10), wherein a surface of the electroconductive support of the electrophotographic photosensitive member has been subjected to an anodized film treatment. (12) A plurality of image forming elements comprising at least a charging unit, an exposing unit, a developing unit, a transferring unit, and an electrophotographic photoreceptor are arranged. (13) The electrophotographic apparatus according to any one of (1) to (12), wherein the charging means of the electrophotographic apparatus uses a contact charging method. Electrophotographic apparatus described in Crab ", (1 (15) The electrophotographic apparatus according to any one of the above (1) to (13), wherein a non-contact proximity arrangement method is used for a charging unit of the electrophotographic apparatus. (16) The electrophotographic apparatus according to the above (14), wherein the gap between the charging member used for the charging unit and the photoconductor is 200 μm or less. (13) The electrophotographic apparatus according to any one of the above (13) to (15), wherein an AC superimposed voltage is applied. Items (1) to (16), wherein the apparatus main body and a detachable cartridge are integrated with one unit selected from a charging unit, an exposure unit, a developing unit, and a cleaning unit. Electronic copy described in any of the items It is solved by "a true device."

As an effect of the present invention, an electrophotographic apparatus that outputs a stable image without thickening of characters even when repeatedly used at high speed is provided. Specifically, an electrophotographic apparatus is provided in which the deterioration and instability of the light source are eliminated and the surface potential (exposed portion, unexposed portion) of the photoreceptor is high. Further, even when a non-halogen solvent is used in the coating solution for the charge transport layer, an electrophotographic apparatus which maintains the high sensitivity inherent in titanyl phthalocyanine is provided.

First, the electrophotographic apparatus of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic diagram for explaining an electrophotographic process and an electrophotographic apparatus of the present invention, and the following modified examples also belong to the category of the present invention.
In FIG. 1, it is essential that the movement time of the surface of the photoconductor moving between the image exposure section (25) and the developing unit (26) be 200 msec or less. At this time, the time from the exposure unit to the developing unit is obtained by dividing the circumference from the photosensitive member surface position facing the center of the image exposure unit to the photosensitive member surface facing the center of the developing unit by the linear speed of the photosensitive member. Is required by
The photoreceptor (21) is provided with a photosensitive layer including at least a charge generation layer and a charge transport layer on a conductive support. The charge generation layer has a diffraction peak at a Bragg angle of 2θ with respect to CuKα radiation (wavelength: 1.542 °). (± 0.2 °), has a maximum diffraction peak at least at 27.2 °, further has major peaks at 9.4 °, 9.6 °, and 24.0 °, and has the lowest angle side. Contains a titanyl phthalocyanine crystal having a peak at 7.3 ° as a diffraction peak, having no peak between the peak at 7.3 ° and the peak at 9.4 °, and further having a peak at 26.3 °. Do it. The photoconductor (21) has a drum shape, but may have a sheet shape or an endless belt shape. The charging roller (23), the pre-transfer charger (27), the transfer charger (30), the separation charger (31), and the pre-cleaning charger (33) include a corotron, a scorotron, a solid state charger (solid state charger), Known means such as a roller and a transfer roller are used.

Among these charging systems, at least a charging member (noted as a charging roller (23) in FIG. 1) used for main charging of the photoconductor is provided with a contact charging system or a non-contact proximity arrangement system. Is desirable. The charging member of the contact charging type or the non-contact proximity arrangement type has advantages such as high charging efficiency, small ozone generation amount, and downsizing of the device.

Here, the contact-type charging member is of a type in which the surface of the charging member comes into contact with the surface of the photoreceptor, and includes a charging roller, a charging blade, and a charging brush. Among them, a charging roller and a charging brush are preferably used.
In addition, the charging member disposed close to the charging member is a type in which the charging member is disposed in a non-contact state so as to have a gap (gap) of 200 μm or less between the surface of the photoconductor and the surface of the charging member. If this gap is too large, charging tends to be unstable, and if it is too small, the surface of the charging member may be contaminated if toner remaining on the photoreceptor exists. . Therefore, the gap is suitably in the range of 10 to 200 μm, preferably 10 to 100 μm. From the distance of the air gap, it is distinguished from a known charging wire type charger such as a corotron and a scorotron, and a contact charging member such as a contact type charging roller, a charging brush, and a charging blade.

Since the surface of such a charging member is placed in a state of non-contact with the surface of the photoreceptor, there is little toner contamination on the surface of the charging member, little wear on the surface of the charging member, and physical properties of the surface of the charging member. In this case, the charging member has an advantage that it has little static / chemical deterioration, and a high durability of the charging member itself can be realized. When the above-mentioned problems occur due to the use of the contact charging member and the durability of the charging member is reduced, the charging ability is reduced or the charging becomes non-uniform in repeated use in the electrophotographic apparatus. Or In order to avoid this charging failure, measures such as increasing the voltage applied to the charging member in accordance with the reduction of the charging ability are taken in repeated use. In that case, the hazard due to the charging of the photoconductor increases, and as a result, the durability of the photoconductor is reduced, and an abnormal image is generated. Further, as the voltage applied to the charging member increases, the durability of the charging member itself also decreases. However, by using a non-contact charging member, the charging capability of the charging member is stabilized due to the high durability of the charging member, thereby improving the durability and stability of the charging member, the photoreceptor, and eventually the entire system. Will be.

The charging member disposed in the vicinity used in the present invention may be of any shape as long as it has a mechanism capable of appropriately controlling the gap with the surface of the photoreceptor. For example, the rotation axis of the photoreceptor and the rotation axis of the charging member may be mechanically fixed so as to have an appropriate gap. Among them, using a charging member in the shape of a charging roller, disposing gap forming members at both ends of the non-image forming portion of the charging member, bringing only this portion into contact with the surface of the photoconductor, and disposing the image forming region in a non-contact manner, Alternatively, a method in which the gap forming member at both ends of the photoreceptor non-image forming portion is arranged, and only this portion is brought into contact with the surface of the charging member, and the image forming region is arranged in a non-contact manner, stably stabilizes the gap by a simple method. It is a method that can be maintained. In particular, the methods described in JP-A-2002-148904 and JP-A-2002-148905 can be used favorably. FIG. 2 shows an example of a proximity charging mechanism in which a gap forming member is arranged on the charging member side. By using the above method, the charging efficiency is high, the amount of generated ozone is small, the size of the device can be reduced, and further, there is an advantage that contamination by toner or the like does not occur and mechanical abrasion due to contact does not occur. Used well because

Further, as an application method, the use of AC superposition has an advantage that charging unevenness is less likely to occur, and can be favorably used. In particular, in a tandem-type full-color image forming apparatus to be described later, in addition to the problem of density unevenness of a halftone image due to uneven charging caused in the case of a monochrome image forming apparatus, there is a major problem of deterioration in color balance (color reproducibility). Connect. By superimposing the AC component on the DC component, the above problem is greatly improved. However, if the conditions of the AC component (frequency and peak-to-peak voltage) are too large, the hazard to the photoconductor becomes large. In some cases, the deterioration of the photoconductor is accelerated. For this reason, the superposition of the AC component should be kept to the minimum necessary.

(4) The frequency of the AC component varies depending on the linear speed of the photoreceptor, but it is appropriate that the frequency is 3 kHz or less, preferably 2 kHz or less. Regarding the peak-to-peak voltage, when plotting the relationship between the voltage applied to the charging member and the charging potential to the photoconductor, there is a region where the photoconductor is not charged even though the voltage is applied, and charging rises from a certain point. A potential is observed. Approximately twice the rising potential is an optimal potential (usually about 1200 to 1500 V) as a peak-to-peak voltage. However, when the charging ability of the photoreceptor is low or the linear velocity is very high, the peak-to-peak voltage twice as high as the rising potential as described above may be insufficient. Conversely, when the chargeability is good, even if the chargeability is twice or less, the potential stability may be sufficiently exhibited. Therefore, the peak-to-peak voltage is preferably three times or less, and more preferably twice or less, the rising potential. If the peak-to-peak voltage is rewritten as an absolute value, it is desirable that the voltage is used at 3 kV or less, preferably 2 kV or less, more preferably 1.5 kV.

The image exposure section (25) uses a light source that can ensure high brightness, such as a light emitting diode (LED), a semiconductor laser (LD), and electroluminescence (EL), and can write at a high resolution of 600 dpi or more. Is done. In particular, in an image forming operation (image writing by a light source) in an electrophotographic apparatus, an exposure amount (exposure energy) of 5 erg / cm ² or less is used. The maximum exposure amount here indicates the amount of writing when image light is written in binary, and when the image light is written in another stage of gradation (multi-valued), the lowest potential is toned. (The highest image density). Further, when a plurality of writing light sources are used and writing is performed by overlapping them as necessary, the total writing light amount is indicated.

The exposure energy can be determined as follows. Normally, when an LD is used, writing is performed by scanning the surface of the photoconductor using a polygon mirror or the like. Therefore, the exposure energy written on the photoreceptor measures the amount of light (power) of the stationary beam, and indicates the effective scanning period ratio (which indicates how much of the light changed by the polygon mirror has been used effectively). Yes, given as the ratio of the effective deflection angle to the deflection angle per polygon mirror surface), the effective writing width, and the linear velocity of the photoconductor.
Exposure energy = (static power × effective scanning period rate) / (effective writing width × photoconductor linear velocity)

For the light source such as the static elimination lamp (22), use all luminescent materials such as a fluorescent lamp, a tungsten lamp, a halogen lamp, a mercury lamp, a sodium lamp, a light emitting diode (LED), a semiconductor laser (LD), and an electroluminescence (EL). Can be. Then, in order to irradiate only light in a desired wavelength range, various filters such as a sharp cut filter, a band pass filter, a near infrared cut filter, a dichroic filter, an interference filter, and a color temperature conversion filter can be used. Among these light sources, light-emitting diodes and semiconductor lasers have high irradiation energy and long-wavelength light of 600 to 800 nm, so that the specific crystal phthalocyanine pigment, which is a charge generation material used in the present invention, has high sensitivity. It is used well because it shows.

Such a light source or the like irradiates the photoreceptor with light by providing a transfer step, a charge removal step, a cleaning step, or a pre-exposure step using light irradiation in addition to the step shown in FIG.
In the case where the AC component is superimposed and used in the previous charging system, or when the residual potential of the photoconductor is small, the charge removing mechanism can be omitted. In addition, instead of an optical charge elimination, an electrostatic charge elimination mechanism (for example, a charge elimination brush to which a reverse bias is applied or grounded) can be used.

Now, the toner developed on the photoconductor (21) by the developing unit (26) is transferred to the transfer paper (29), but not all is transferred, and remains on the photoconductor (21). Toner also forms. Such toner is removed from the photoreceptor by the fur brush (34) and the blade (35). Cleaning may be performed only with a cleaning brush, and a known brush such as a fur brush or a mag fur brush is used as the cleaning brush. Of course, when the transfer efficiency is high and the residual toner amount is small, such a cleaning mechanism can be omitted.

When a positive (negative) charge is applied to the electrophotographic photosensitive member and image exposure is performed, a positive (negative) electrostatic latent image is formed on the surface of the photosensitive member.
If this is developed with a toner of negative (positive) polarity (electrostatic detection fine particles), a positive image is obtained, and if it is developed with a toner of positive (negative) polarity, a negative image is obtained.
A known method is applied to the developing unit, and a known method is also used for the charge removing unit.

FIG. 3 shows another example of the electrophotographic process according to the present invention. Also in this case, it is essential that the movement time of the surface of the photoconductor moving between the image exposure unit (64) and the developing unit (69) be 200 msec or less. The photoreceptor (61) is provided with at least a photosensitive layer including a charge generation layer and a charge transport layer on a conductive support. (± 0.2 °), has a maximum diffraction peak at least at 27.2 °, further has major peaks at 9.4 °, 9.6 °, and 24.0 °, and has the lowest angle side. Contains a titanyl phthalocyanine crystal having a peak at 7.3 ° as a diffraction peak, having no peak between the peak at 7.3 ° and the peak at 9.4 °, and further having a peak at 26.3 °. Do it. Driven by the drive rollers (62a) and (62b), charging by the charger (63), image exposure by the light source (64), development (not shown), transfer using the charger (65), and transfer by the light source (66) Exposure before cleaning, cleaning with a brush (67), and static elimination with a light source (68) are repeatedly performed. In FIG. 3, the photosensitive member (61) (of course, the support is translucent) is irradiated with light for image exposure from the support side. As the image exposure source (64) having a resolution of 600 dpi or more, an LD or an LED is preferably used, and is used at a maximum exposure amount (exposure energy) of 5 erg / cm ² or less.

The illustrated electrophotographic process is an example of an embodiment of the present invention, and other embodiments are of course possible. For example, although the pre-cleaning exposure is performed from the photosensitive layer side in FIG. 3, this may be performed from the translucent support side, or the irradiation of the static elimination light may be performed from the support side.
On the other hand, in the light irradiation step, image exposure, pre-cleaning exposure, and charge removal exposure are shown, but in addition, pre-transfer exposure, pre-exposure of image exposure, and other known light irradiation steps are provided, and the photoconductor is exposed to light. Irradiation can also be performed.

The image forming means as described above may be fixedly incorporated in a copying apparatus, a facsimile, or a printer, or may be incorporated in the apparatus in the form of a process cartridge. The process cartridge is one device (part) that includes a photoconductor and further includes a charging unit, an exposure unit, a developing unit, a transfer unit, a cleaning unit, a charge removing unit, and the like. Although there are many shapes and the like of the process cartridge, a general example is shown in FIG. Also in this case, it is essential that the time of the surface of the photoconductor moving between the image exposure section (75) and the developing roller (77) is 200 msec or less.
The photoreceptor (71) is provided with a photosensitive layer including at least a charge generation layer and a charge transport layer on a conductive support. (± 0.2 °), has a maximum diffraction peak at least at 27.2 °, further has major peaks at 9.4 °, 9.6 °, and 24.0 °, and has the lowest angle side. Contains a titanyl phthalocyanine crystal having a peak at 7.3 ° as a diffraction peak, having no peak between the peak at 7.3 ° and the peak at 9.4 °, and further having a peak at 26.3 °. Do it. When the process cartridge is used in an image forming apparatus, irradiation of image writing light having a resolution of 600 dpi or more is used with an exposure amount (exposure energy) of 5 erg / cm ² or less at the maximum.

FIG. 5 is a schematic diagram for explaining a tandem-type full-color electrophotographic apparatus of the present invention, and the following modified examples also belong to the category of the present invention.
In FIG. 5, reference numerals (1C), (1M), (1Y), and (1K) denote drum-shaped photoconductors, on which a photosensitive layer including at least a charge generation layer and a charge transport layer is provided on a conductive support. The charge generation layer has a maximum diffraction peak at least at 27.2 ° as a diffraction peak (± 0.2 °) at a Bragg angle of 2θ with respect to CuKα radiation (wavelength 1.542 °), and further has a peak of 9.4 °. , 9.6 °, 24.0 °, and the lowest diffraction peak at 7.3 °, the 7.3 ° peak and the 9.4 ° peak. And a titanyl phthalocyanine crystal having a peak at 26.3 °.
In FIG. 5, reference numerals (1C), (1M), (1Y), and (1K) denote drum-shaped photoconductors, and the photoconductors (1C), (1M), (1Y), and (1K) are shown in FIG. , Around which at least the charging members (2C), (2M), (2Y) and (2K), the developing members (4C), (4M), (4Y) and (4K), the cleaning members The members (5C), (5M), (5Y) and (5K) are arranged. The charging members (2C), (2M), (2Y) and (2K) are charging members constituting a charging device for uniformly charging the surface of the photoconductor. An exposure member (not shown) is provided on the surface of the photoconductor between the charging members (2C), (2M), (2Y), and (2K) and the developing members (4C), (4M), (4Y), and (4K). Laser light (3C), (3M), (3Y), and (3K) having a resolution of 600 dpi or more is irradiated, and electrostatic latent images are formed on photoconductors (1C), (1M), (1Y), and (1K). Is formed. Here, it is essential that the time of the surface of the photoconductor moving between the image exposure unit (3C, 3M, 3Y, 3K) and the developing unit (4C, 4M, 4Y, 4K) be 200 msec or less. The four image forming elements (6C), (6M), (6Y), and (6K) centered on such photoconductors (1C), (1M), (1Y), and (1K) are transferred to a transfer material. They are juxtaposed along a transfer conveyance belt (10) as a conveyance means. The transfer conveyance belt (10) includes the developing members (4C), (4M), (4Y), and (4K) of the image forming units (6C), (6M), (6Y), and (6K), and the cleaning member (5C). , (5M), (5Y), and (5K) are in contact with the photoconductors (1C), (1M), (1Y), and (1K), and hit the rear side of the transfer / conveyor belt (10) on the photoconductor side. Transfer brushes (11C), (11M), (11Y) and (11K) for applying a transfer bias are arranged on the surface (back surface). Each of the image forming elements (6C), (6M), (6Y) and (6K) is different in the color of the toner inside the developing device, and all the other components have the same configuration.

(5) In the color electrophotographic apparatus having the configuration shown in FIG. 5, the image forming operation is performed as follows. First, in each of the image forming elements (6C), (6M), (6Y), and (6K), the photoconductors (1C), (1M), (1Y), and (1K) move in the direction of the arrow (the direction around the photoconductor). ), Which is charged by the charging members (2C), (2M), (2Y), and (2K), and then exposed to laser beams (3C), (3M) by an exposure unit (not shown) arranged inside the photoconductor. ), (3Y) and (3K), an electrostatic latent image corresponding to each color image to be created is formed. Next, the latent images are developed by the developing members (4C), (4M), (4Y) and (4K) to form toner images. Developing members (4C), (4M), (4Y), and (4K) are developing members that develop with C (cyan), M (magenta), Y (yellow), and K (black) toners, respectively. The toner images of the respective colors formed on the photoconductors (1C), (1M), (1Y) and (1K) are superimposed on the transfer paper. The transfer paper (7) is sent out of the tray by a paper feed roller (8), temporarily stopped by a pair of registration rollers (9), and is transferred to a transfer conveyance belt (10) at the same time as the image formation on the photoconductor. Sent. The transfer paper (7) held on the transfer conveyance belt (10) is conveyed, and each color is transferred at a contact position (transfer portion) with each of the photoconductors (1C), (1M), (1Y) and (1K). The transfer of the toner image is performed. The toner image on the photoreceptor is formed by the transfer bias applied to the transfer brushes (11C), (11M), (11Y), and (11K) and the photoreceptors (1C), (1M), (1Y), and (1K). Is transferred onto the transfer paper (7) by the electric field formed from the potential difference of Then, the recording paper (7) on which the four color toner images are superposed through the four transfer units is conveyed to a fixing device (12), where the toner is fixed, and is discharged to a discharge unit (not shown). Further, the residual toner remaining on each of the photoconductors (1C), (1M), (1Y) and (1K) without being transferred in the transfer section is removed by cleaning devices (5C), (5M), (5Y) and (5Y). 5K). In the example of FIG. 5, the image forming elements are arranged in the order of C (cyan), M (magenta), Y (yellow), and K (black) from the upstream side to the downstream side in the transfer paper transport direction. However, the order is not limited to this order, and the color order is arbitrarily set. Also, when a black-only document is created, providing a mechanism that stops the image forming elements (6C), (6M), and (6Y) other than black can be particularly effectively used in the present invention. Further, although the charging member is in contact with the photoreceptor in FIG. 5, a suitable gap (about 10 to 200 μm) is provided between the charging member and the charging mechanism as shown in FIG. In addition, the amount of wear of both can be reduced, and the amount of toner filming on the charging member can be reduced, and it can be used favorably.

The image forming means as described above may be fixedly incorporated in a copying apparatus, a facsimile, or a printer, but each electrophotographic element may be incorporated in the apparatus in the form of a process cartridge. . The process cartridge is one device (part) including a photoconductor and further including a charging unit, an exposing unit, a developing unit, a transferring unit, a cleaning unit, a discharging unit, and the like.

The effects of the present invention are considered as follows.
The electrophotographic apparatus to which the present invention is applied targets a high-speed and high-resolution area. Therefore, the system is operated in the region of 150 mm / sec or more (more preferably 200 mm / sec or more) at the linear velocity of the photosensitive member, and the beam system of the writing light by LD or LED also corresponds to 600 dpi or more (preferably 1200 dpi or more). Then, it is performed at 50 μm or less (preferably 30 μm or less). In such a case, even if the output of the light source is increased, the exposure energy when reaching the photoconductor surface is limited, and unless the life of the light source and the output stability are ignored, the surface of the photoconductor during continuous operation is not affected. Has an exposure energy of at most 10 erg / cm ² or less.
Usually, such an optical system is not easy to replace and is designed to have the same life as the main body of the electrophotographic apparatus. Therefore, in consideration of device fabrication accuracy (lot difference), stability in a use environment, reliable securing of life, output stability during continuous operation, and the like, it is preferable to use the device at about half the power of the full output of the device. .
As the characteristics (light attenuation characteristics) of the photoconductor in such a system, both high response (faster potential attenuation) and high gain (larger potential attenuation) are required. Among them, as described above, regarding the high response, the recent development of the charge transporting material has made it possible to correspond to a high-speed system in which the time between writing and development is 100 msec or less. This also supports the fact that high-intensity writing such as laser light causes photocarrier generation of the photoreceptor in a region of reciprocity failure.

On the other hand, with regard to high gain, charge generation materials have been developed in parallel with the development of charge transport materials, and charge generation materials exhibiting extremely high quantum efficiency have been successfully developed. For example, the specific crystal type titanyl phthalocyanine crystal mentioned above corresponds to this. However, although gain can be gained indeed, it is still possible to cope with the optimal use of the light source (writing of a small area, reduction of the writing light amount by writing at high speed) in terms of light attenuation. I can't say that. This is shown in FIG.

FIG. 6 shows the light attenuation characteristics of a photoreceptor using a titanyl phthalocyanine crystal (a crystal having a maximum diffraction peak at least 27.2 ° as a diffraction peak at a Bragg angle of 2θ with respect to CuKα radiation) as a charge generation material. It is shown in B in FIG. The light attenuation characteristic when the charge generation material (specific crystal type titanyl phthalocyanine) used in the present invention is used is A in FIG. The difference between the two is the difference in quantum efficiency (at a low electric field) because the amounts of the charge generating substances deposited are equal.
In the light attenuation characteristic of B, the light attenuation is not completed at an exposure amount of about 5 erg / cm ² , and the potential obtained (corresponding to the exposed portion potential) is higher than that of A. For this reason, depending on the setting of the developing bias, as a result, a phenomenon that the image density is reduced and a phenomenon that one dot cannot be reliably developed easily occurs. For this reason, in order to further lower the potential, an exposure amount of 5 erg / cm ² or more is required. As a result, the light source is used with high luminance, which not only shortens the life of the light source, Decreases stability when used repeatedly. In addition, since an excessive amount of light is applied, light fatigue of the photosensitive member is promoted, and side effects such as diffusion of dots (thicker lines) are generated. This problem is very remarkable in an electrophotographic apparatus that performs writing with a resolution of 600 dpi or more, and must be solved in order to improve the resolution.

On the other hand, in the case of having the light attenuation characteristic of A, the light attenuation is almost completed at an exposure amount of about 5 erg / cm ² . This makes it possible to set the output of the light source to be low, and has the effect of reducing the life, stability, and light fatigue of the photoconductor. At the same time, the use of such a high-gain photoreceptor with a good skirt makes it possible to further reduce the potential of the unexposed portion, and to prevent background contamination which is a fatal defect in negative-positive development. This also has the advantage that the margin is improved. In addition, the existence of the saturation value of the potential decay in the effective use range of the light quantity (the range in which the light emission is reasonably provided) gives a margin to the light quantity distribution in one dot of the writing light. This is very advantageous in that a faithful latent image is formed.
Conversely, when a light amount of 5 erg / cm ² or more is applied to the photoreceptor showing the light attenuation of A, the line has a disadvantage that the line becomes thick as described above. This phenomenon can be avoided by using a smaller amount of light (4.5 erg / cm ² or less as shown in FIG. 6A).

Hereinafter, the electrophotographic photosensitive member used in the present invention will be described in detail.
The electrophotographic photoreceptor of the present invention is an electrophotographic photoreceptor having at least a charge generation layer and a charge transport layer formed on a conductive support, wherein the charge generation layer contains CuKα rays (wavelength 1.542 °). Has a maximum diffraction peak at least at 27.2 ° and a major peak at 9.4 °, 9.6 ° and 24.0 ° as a diffraction peak (± 0.2 °) at a Bragg angle of 2θ. And has a peak at 7.3 ° as the diffraction peak on the lowest angle side, has no peak between the peak at 7.3 ° and the peak at 9.4 °, and further has a peak at 26.3 °. Containing a titanyl phthalocyanine crystal having the formula:
This crystal form is described in JP-A-2001-187794. By using this titanyl phthalocyanine crystal, a stable charge that does not cause a decrease in chargeability even when repeatedly used without losing high sensitivity. An electrophotographic photosensitive member can be obtained. Japanese Patent Application Laid-Open No. 2001-187794 discloses a charge generating substance used in the present invention, a photoreceptor using the same, and an electrophotographic apparatus. However, in a situation where the resolution is used at a resolution of 600 dpi or more, unless the writing fee is optimized, the above-described character fattening phenomenon is caused, and the resolution is substantially reduced. . Such a phenomenon is more prominent in a photoreceptor using the material described in the publication than in a photoreceptor having a lower sensitivity. As described above, in the past processes (apparatuses), not only the ability of the materials described in the publication is not fully exploited, but also adverse effects are produced unless the process conditions are optimized.

As a method for synthesizing titanyl phthalocyanine crystals, a method not using a titanium halide as a raw material, as described in JP-A-6-29369, is preferably used. The greatest advantage of this method is that the synthesized titanyl phthalocyanine crystal is halogen-free. When a titanyl phthalocyanine crystal contains a halogenated titanyl phthalocyanine crystal as an impurity, the electrostatic characteristics of a photoreceptor using the same often have adverse effects such as a decrease in photosensitivity and a decrease in chargeability. Shu p.103 1989). The present invention is also directed mainly to halogenated free titanyl phthalocyanine crystals as described in JP-A-2001-187794, and these materials are effectively used.

First, a method for synthesizing a titanyl phthalocyanine crystal having a specific crystal type used in the present invention will be described.
First, a method for synthesizing a crude product of titanyl phthalocyanine crystal will be described. Methods for synthesizing phthalocyanines have been known for a long time, and are described in Moser et al., "Phthalocyanine Compounds" (1963), "The Phthalocyanines" (1983), JP-A-6-29369.

For example, the first method is a method in which a mixture of phthalic anhydrides, metals or metal halides and urea is heated in the presence or absence of a high boiling point solvent. In this case, a catalyst such as ammonium molybdate is used as needed. A second method is a method in which phthalonitriles and a metal halide are heated in the presence or absence of a high boiling point solvent. This method is used for phthalocyanines that cannot be produced by the first method, for example, aluminum phthalocyanines, indium phthalocyanines, oxovanadium phthalocyanines, oxotitanium phthalocyanines, zirconium phthalocyanines, and the like. A third method is to first react ammonia with phthalic anhydride or phthalonitriles to produce an intermediate such as 1,3-diiminoisoindoline, and then react with a metal halide in a high boiling solvent. It is a way to make it. The fourth method is a method in which a phthalonitrile is reacted with a metal alkoxide in the presence of urea or the like. In particular, the fourth method does not cause chlorination (halogenation) to a benzene ring, and is a very useful method for synthesizing an electrophotographic material.

Next, a method for synthesizing amorphous titanyl phthalocyanine (low crystalline titanyl phthalocyanine) will be described. In this method, a phthalocyanine is dissolved in sulfuric acid, then diluted with water and reprecipitated, and a method called an acid paste method or an acid slurry method can be used.
As a specific method, the above synthesized crude product is dissolved in 10 to 50 times the volume of concentrated sulfuric acid, and if necessary, insolubles are removed by filtration or the like, and this is sufficiently cooled to 10 to 50 times the volume of sulfuric acid. Slowly put into water or ice water to reprecipitate titanyl phthalocyanine. After filtration of the precipitated titanyl phthalocyanine, washing and filtration are performed with ion-exchanged water, and this operation is sufficiently repeated until the filtrate becomes neutral. Finally, after washing with clean ion-exchanged water, filtration is performed to obtain a water paste having a solid concentration of about 5 to 15% by weight. The product thus prepared is amorphous titanyl phthalocyanine (low crystalline titanyl phthalocyanine) used in the present invention. At this time, this amorphous titanyl phthalocyanine (low-crystalline titanyl phthalocyanine) has a diffraction peak (± 0.2 °) at a Bragg angle 2θ of at least 7.0 to 7 with respect to the characteristic X-ray of CuKα (wavelength 1.542 °). It preferably has a maximum diffraction peak at 0.5 °. In particular, the half width of the diffraction peak is more preferably 1 ° or more. Further, the average particle size of the primary particles is preferably 0.1 μm or less.

Next, a crystal conversion method will be described. In the present invention, titanyl phthalocyanine crystals are synthesized by at least two crystal conversion steps.
First, the first crystal conversion method will be described. In the first crystal transformation, the amorphous titanyl phthalocyanine (low-crystalline titanyl phthalocyanine) is converted into a characteristic peak of CuKα (wavelength 1.542 °) as a diffraction peak (± 0.2 °) at a Bragg angle 2θ of at least 27%. 0.2 °, the maximum diffraction peak at 9.4 °, 9.6 °, and 24.0 °, and the peak at 7.3 ° as the lowest angle diffraction peak. This is a step of converting into a titanyl phthalocyanine crystal having no peak between 7.3 ° and 9.4 ° and having no peak at 26.3 °.

As a specific method, the amorphous form of titanyl phthalocyanine (low-crystalline titanyl phthalocyanine) is not dried, but is mixed and stirred with an organic solvent in the presence of water to obtain the crystal form. .
At this time, as the organic solvent used, any organic solvent can be used as long as a desired crystal form can be obtained, and in particular, tetrahydrofuran, toluene, methylene chloride, carbon disulfide, orthodichlorobenzene, 1,1,1 Good results are obtained when one selected from 2-trichloroethane is selected. These organic solvents are preferably used alone, but it is also possible to use a mixture of two or more of these organic solvents or a mixture with another solvent. The amount of the organic solvent used for the crystal conversion is preferably at least 10 times, preferably at least 30 times the weight of the amorphous titanyl phthalocyanine. This is because crystal conversion is quickly and sufficiently caused, and an effect of sufficiently removing impurities contained in amorphous titanyl phthalocyanine is exhibited. The amorphous titanyl phthalocyanine used here is produced by an acid paste method, but it is desirable to use one obtained by sufficiently washing sulfuric acid as described above. If the crystal conversion is carried out under the condition that sulfuric acid remains, sulfate ions remain in the crystal particles, and the resulting crystals cannot be completely removed even by an operation such as a water washing treatment. If sulfate ions remain, favorable results cannot be obtained, such as lowering the sensitivity of the photoreceptor and lowering the chargeability. For example, JP-A-8-110649 (Comparative Example) describes a method in which titanyl phthalocyanine dissolved in sulfuric acid is charged into an organic solvent together with ion-exchanged water to perform crystal transformation. At this time, a crystal similar to the X-ray diffraction spectrum of the titanyl phthalocyanine crystal obtained in the present invention can be obtained, but the sulfate ion concentration in the titanyl phthalocyanine is high, and the light attenuation characteristic (light sensitivity) is poor. However, the method for producing titanyl phthalocyanine of the present invention is not good.

The above-described crystal conversion method is a crystal conversion method according to JP-A-2001-187794. The effect of the charge generating substance contained in the photoreceptor used in the electrophotographic apparatus of the present invention becomes more remarkable by reducing the particle size of the titanyl phthalocyanine crystal.
In order to make the particle size of the titanyl phthalocyanine crystal finer, according to observations by the present inventors, in the operation of crystal transformation, the above-mentioned amorphous titanyl phthalocyanine (low-crystalline titanyl phthalocyanine) has a primary particle size. Although it is 0.1 μm or less (mostly about 0.01 to 0.05 μm), it was found that the crystal was converted along with the crystal growth during the crystal conversion. Usually, in this type of crystal conversion, a sufficient crystal conversion time is secured due to fear of remaining raw materials, and after the crystal conversion is performed sufficiently, filtration is performed, and titanyl phthalocyanine crystal having a desired crystal form is obtained. Is what you get. For this reason, despite the fact that a raw material having sufficiently small primary particles is used as the raw material, a crystal having a large primary particle (generally 0.3 to 0.5 μm) is obtained as a crystal after the crystal conversion. is there.

In dispersing the titanyl phthalocyanine crystal thus produced, a strong share is required in order to reduce the particle size after dispersion (less than 0.3 μm, preferably 0.25 μm or less, more preferably 0.2 μm or less). To disperse, and if necessary, a strong energy for pulverizing the primary particles is applied to perform dispersion. As a result, as described above, a result that a part of the particles easily transitions to a crystal form other than a desired crystal form is produced.
The particle size as referred to herein is a volume average particle size, which is determined by an ultracentrifugal automatic particle size distribution analyzer: CAPA-700 (manufactured by Horiba, Ltd.). In this case, the particle diameter was calculated as a particle diameter (Median type) corresponding to 50% of the cumulative distribution. However, since this method may not be able to detect minute amounts of coarse particles, it is important to determine the size by observing the titanyl phthalocyanine crystal powder or dispersion directly with an electron microscope to determine the size in more detail. It is.

に 対 し て In response to this fact, it is an effective means to make the primary particles produced at the time of the first crystal transformation as small as possible. For this purpose, a suitable solvent for the crystal conversion is selected as described above, and the solvent and the titanyl phthalocyanine aqueous paste (the raw material prepared as described above) are used to enhance the crystal conversion efficiency and complete the crystal conversion in a short time. The method of using strong agitation in order to bring the) into sufficient contact is effective. More specifically, a method of using a propeller having a very strong stirring power, or using an intense stirring (dispersion) means such as a homogenizer (homomixer) to realize crystal conversion in a short time. is there. Under these conditions, it is possible to obtain a titanyl phthalocyanine crystal in which the crystal conversion is sufficiently performed and no crystal growth occurs without leaving any raw material.

As described above, since the crystal particle size and the crystal conversion time are in a proportional relationship, a method of immediately stopping the reaction when a predetermined reaction (crystal conversion) is completed is also an effective means. As described above, a large amount of a solvent that is unlikely to undergo crystal conversion immediately after the crystal conversion as described above is added. Examples of the solvent that does not easily undergo crystal transformation include alcohol-based and ester-based solvents. Crystal conversion can be stopped by adding these solvents about 10 times to the crystal conversion solvent. By employing such a crystal conversion method, a titanyl phthalocyanine crystal having a small primary particle size (less than 0.3 μm, preferably 0.25 μm or less, more preferably 0.2 μm or less) can be obtained. In addition to the technique described in Japanese Patent Application Laid-Open No. 2001-19871, the use of the technique described above (a crystal conversion method for obtaining a fine titanyl phthalocyanine crystal), if necessary, can reduce the effects of the present invention. It is an effective means to increase.

Subsequently, the crystal-converted titanyl phthalocyanine crystal is immediately filtered to be separated from the crystal conversion solvent. The filtration is performed by using a filter having an appropriate size. At this time, it is most appropriate to use vacuum filtration.
Thereafter, the separated titanyl phthalocyanine crystals are heated and dried as necessary. Any known dryers can be used for drying by heating.
When the drying is performed in the atmosphere, a blast dryer is preferable. Further, drying under reduced pressure is also a very effective means for increasing the drying speed and more remarkably exhibiting the effects of the present invention. In particular, it is an effective means for a material that decomposes at a high temperature or changes its crystal form. In particular, it is effective to dry in a state where the degree of vacuum is higher than 10 mmHg.

Next, the second crystal conversion method will be described. The second crystal transformation is a step of further performing a crystal transformation using the titanyl phthalocyanine crystal (dry powder) produced in the first crystal transformation. As a specific method, there are two types of methods.
One is a method of treating the previously prepared titanyl phthalocyanine crystal in an organic solvent. As the organic solvent to be used, any solvent can be used as long as it can convert a crystal form having a maximum diffraction peak at 27.2 ° into a crystal form having a maximum diffraction peak at 26.3 °. Aromatic hydrocarbons such as xylene, ketones such as acetone and 2-butanone, halogenated hydrocarbons such as methylene chloride and chloroform, and cyclic ethers such as tetrahydrofuran are preferably used.
Regarding the treatment of the organic solvent, the titanyl phthalocyanine crystal may be simply immersed in the organic solvent as it is, but the treatment time can be shortened by using auxiliary means such as stirring and ultrasonic application. ,It is valid. After the treatment with the organic solvent, the mixture is separated by filtration and dried again, whereby the target titanyl phthalocyanine crystal can be obtained.

Another method is a method of performing a crystal transformation by applying a mechanical shearing force to the titanyl phthalocyanine crystal prepared above. At this time, an organic solvent may be used in combination, but it is preferable to perform the treatment in a dry state without using the organic solvent. As a method to be used, dry milling using a ball mill, an attritor, a vibration mill, a kneader, or the like, or simply, dry milling using a mixer is also effective. In addition, at the time of dry milling, an inorganic salt such as salt may be used as an auxiliary. When an auxiliary agent is used, a washing step for removing inorganic salts is required after the crystal conversion treatment. Thus, the desired titanyl phthalocyanine crystal can be obtained.
Whichever method is used, it is important that the peak intensity at 26.3 ° is in the range of 0.1 to 5% of the peak intensity at 27.2 ° at the maximum diffraction peak. The peak intensity of 26.3 ° is determined by the treatment time in a solvent or the treatment time of applying a mechanical shearing force, and the state of the raw material (the titanyl phthalocyanine crystal produced by the first crystal transformation) (for example, It depends on the size, hardness, etc. of the powder), so it is desirable to determine the treatment time by preliminary experiments.

The thus obtained titanyl phthalocyanine crystal having a specific crystal form is extremely useful as a charge generating substance for an electrophotographic photosensitive member. However, as described above, the crystal form is unstable and has a disadvantage that the crystal form is easily transferred when a dispersion is prepared. However, as described above, by synthesizing the primary particles into an extremely small one, a dispersion having a small average particle diameter can be produced without giving an excessive share at the time of producing the dispersion, and the crystal form is also reduced. It can be produced extremely stably (without changing the synthesized crystal form).
A general method is used for preparing the dispersion, and the titanyl phthalocyanine crystal is dispersed in a suitable solvent together with a binder resin as necessary using a ball mill, an attritor, a sand mill, a bead mill, ultrasonic waves, or the like. It is obtained. At this time, the binder resin may be selected according to the electrostatic characteristics of the photoreceptor, and the solvent may be selected according to the wettability to the pigment, the dispersibility of the pigment, and the like.

As described above, a titanyl phthalocyanine crystal having a maximum diffraction peak at least at 27.2 ° as a diffraction peak (± 0.2 °) at a Bragg angle of 2θ with respect to CuKα radiation (wavelength: 1.542 °) is obtained by thermal energy / mechanical It is known that a crystal transition easily occurs to another crystal type due to stress such as a target shear. This tendency does not change in the titanyl phthalocyanine crystal used in the present invention. That is, in order to produce a dispersion liquid containing fine particles, it is necessary to devise a dispersion method. However, there is a tendency that the stability of the crystal form and the formation of fine particles are in a trade-off relationship. There is a method of avoiding this by optimizing the dispersion conditions, but in any case, the production conditions are extremely narrowed, and a simpler method is desired. To solve this problem, the following method is also an effective means.

That is, this is a method in which a dispersion liquid in which particles are made as fine as possible within a range in which crystal transition does not occur is produced, and then filtered through an appropriate filter. This method can remove even small amounts of coarse particles that cannot be observed visually (or cannot be detected by particle size measurement), and is a very effective means from the viewpoint of uniforming the particle size distribution. Specifically, the dispersion prepared as described above is filtered through a filter having an effective pore size of 3 μm or less to complete the dispersion. According to this method, a dispersion containing only titanyl phthalocyanine crystal having a small particle size (less than 0.3 μm, preferably 0.25 μm or less, more preferably 0.2 μm or less) can be prepared. The effect of the present invention can be made even more remarkable by mounting and using the body.

The ratio of the peak intensity at 26.3 ° to the peak intensity at 27.2 ° in the titanyl phthalocyanine crystal of the present invention will be described.
An X-ray diffraction spectrum of the titanyl phthalocyanine crystal to be used is measured in a powder state using a general X-ray diffractometer. After performing baseline correction on the obtained spectrum, a peak intensity of 26.3 ± 0.2 ° and a peak intensity of 27.2 ± 0.2 ° are obtained. The value obtained by dividing the peak intensity at 26.3 ± 0.2 ° by the peak intensity at 27.2 ± 0.2 ° using this value is the peak intensity ratio referred to in the present invention.
Peak intensity ratio (%) =
(Peak intensity of 26.3 ± 0.2 ° / peak intensity of 27.2 ± 0.2 °)

When the peak intensity ratio is 1% or less, it may be difficult to correct the baseline in a wide range of measurement. In that case, the intensity ratio can be obtained more accurately by narrowing the measurement range (for example, measuring in the range of 25 to 30 °) and performing re-measurement.

Next, the electrophotographic photosensitive member used in the present invention will be described in detail with reference to the drawings.
FIG. 7 is a cross-sectional view showing a configuration example of the electrophotographic photoreceptor used in the present invention. It has a configuration in which a charge transport layer (47) mainly composed of a transport material is laminated.
FIG. 8 is a cross-sectional view showing another example of the configuration of the electrophotographic photoreceptor used in the present invention. And a charge transport layer (47) containing a charge transport material as a main component, and a protective layer (49) is further laminated thereon.

Examples of the conductive support (41) include those having a conductivity of 10 ¹⁰ Ω · cm or less, for example, metals such as aluminum, nickel, chromium, nichrome, copper, gold, silver, platinum, tin oxide, and oxide. Film or cylindrical plastic or paper coated with metal oxides such as indium by vapor deposition or sputtering, or plates of aluminum, aluminum alloy, nickel, stainless steel, etc. and methods of extrusion, drawing, etc. After it is made into a tube, a tube or the like that has been subjected to surface treatment such as cutting, superfinishing, and polishing can be used. Further, an endless nickel belt and an endless stainless belt disclosed in JP-A-52-36016 can also be used as the conductive support (41).

の Among these, a cylindrical support made of aluminum, which can be easily subjected to the anodic oxide film treatment, can be most preferably used. The aluminum referred to here includes both pure aluminum and aluminum alloy. Specifically, JIS 1000 series, 3000 series, and 6000 series aluminum or aluminum alloy is most suitable. The anodized film is obtained by anodizing various metals and various alloys in an electrolyte solution. Among them, a film called alumite obtained by anodizing aluminum or an aluminum alloy in an electrolyte solution is a photoreceptor used in the present invention. Is most suitable for In particular, it is excellent in preventing point defects (black spots, background stain) generated when used in reversal development (negative / positive development).

The anodic oxidation treatment is performed in an acidic bath such as chromic acid, sulfuric acid, oxalic acid, phosphoric acid, boric acid, and sulfamic acid. Of these, treatment with a sulfuric acid bath is most suitable. For example, sulfuric acid concentration: 10 to 20%, bath temperature: 5 to 25 ° C, current density: 1 to 4 A / dm ² , electrolysis voltage: 5 to 30 V, processing time: about 5 to 60 minutes But is not limited to this. Since the anodic oxide film thus produced is porous and has high insulation properties, the surface is very unstable. For this reason, there is a temporal change after the production, and the physical property value of the anodic oxide film is likely to change. In order to avoid this, it is desirable to further seal the anodic oxide film. Examples of the sealing treatment include a method of immersing the anodic oxide film in an aqueous solution containing nickel fluoride and nickel acetate, a method of immersing the anodic oxide film in boiling water, and a method of performing treatment with pressurized steam. Among them, the method of immersing in an aqueous solution containing nickel acetate is most preferable. Subsequent to the sealing treatment, a cleaning treatment of the anodic oxide film is performed. The main purpose of this is to remove excess metal salts and the like attached by the sealing treatment. If this remains on the surface of the support (anodic oxide film) excessively, it not only adversely affects the quality of the coating film formed thereon, but also generally causes low resistance components to remain. It will also be the cause. The washing may be a single washing with pure water, but usually washing at another stage is performed. At this time, it is preferable that the final cleaning liquid is as clean (deionized) as possible. In addition, it is desirable to perform physical rubbing cleaning with a contact member in one of the other cleaning steps. The thickness of the anodic oxide film formed as described above is desirably about 5 to 15 μm. If it is too thin, the barrier effect of the anodic oxide film is not sufficient, and if it is too thick, the time constant of the electrode becomes too large, resulting in the generation of residual potential and reduced photoconductor response. May be.

In addition, those obtained by dispersing a conductive powder in a suitable binder resin on the above support and applying the same can also be used as the conductive support (41) of the present invention. Examples of the conductive powder include carbon black, acetylene black, metal powder such as aluminum, nickel, iron, nichrome, copper, zinc, and silver, and metal oxide powder such as conductive tin oxide and ITO. Can be The binder resins used simultaneously include polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, and vinyl chloride-vinyl acetate copolymer. , Polyvinyl acetate, polyvinylidene chloride, polyarylate resin, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly-N-vinyl carbazole, acrylic resin, silicone resin, epoxy resin, Thermoplastic, thermosetting resin or photocurable resin such as melamine resin, urethane resin, phenol resin, and alkyd resin. Such a conductive layer can be provided by dispersing the conductive powder and the binder resin in an appropriate solvent, for example, tetrahydrofuran, dichloromethane, methyl ethyl ketone, toluene, or the like, and applying the dispersion.
Further, a heat-shrinkable tube containing the above-mentioned conductive powder in a material such as polyvinyl chloride, polypropylene, polyester, polystyrene, polyvinylidene chloride, polyethylene, chloride rubber, and polytetrafluoroethylene-based fluororesin on a suitable cylindrical substrate. A conductive layer provided with a conductive layer can also be favorably used as the conductive support (41) of the present invention.

Next, the photosensitive layer will be described. As described above, the photosensitive layer is preferably used as a laminated type composed of the charge generation layer (45) and the charge transport layer (47), which exhibits excellent characteristics in sensitivity and durability.
The charge generation layer (45) has a maximum diffraction peak at least 27.2 ° as a diffraction peak (± 0.2 °) at a Bragg angle 2θ with respect to characteristic X-rays of CuKα (wavelength 1.542 °) as a charge generation material. Is a step of converting into a crystalline form). In particular, among the crystal forms, they further have major peaks at 9.4 °, 9.6 °, and 24.0 °, and have a peak at 7.3 ° as the diffraction peak on the lowest angle side, A titanyl phthalocyanine crystal having no peak between the peak at 7.3 ° and the peak at 9.4 °, and further having a peak at 26.3 ° is favorably used, and the peak intensity at 26.3 ° shows the maximum diffraction. Titanyl phthalocyanine crystals having a peak intensity of 27.2% in the range of 0.1 to 5% are particularly preferably used. Further, the fact that the average particle size of the primary particles of the crystal is less than 0.3 μm (preferably 0.25 μm or less, more preferably 0.2 μm or less) further enhances the effects of the present invention, It is an effective means.
The charge generation layer (45) is obtained by dispersing the pigment together with a binder resin as necessary in a suitable solvent using a ball mill, an attritor, a sand mill, ultrasonic waves, or the like, and applying the resultant on a conductive support; It is formed by drying.

If necessary, the binder resin used for the charge generation layer (45) may be, for example, polyamide, polyurethane, epoxy resin, polyketone, polycarbonate, silicon, or the like. Resin, acrylic resin, polyvinyl butyral, polyvinyl formal, polyvinyl ketone, polystyrene, polysulfone, poly-N-vinylcarbazole, polyacrylamide, polyvinyl benzal, polyester, phenoxy resin, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, Examples include polyphenylene oxide, polyamide, polyvinyl pyridine, cellulose resin, casein, polyvinyl alcohol, polyvinyl pyrrolidone, and the like. The amount of the binder resin is suitably 0 to 500 parts by weight, preferably 10 to 300 parts by weight, per 100 parts by weight of the charge generating substance.

溶 剤 Examples of the solvent used herein include isopropanol, acetone, methyl ethyl ketone, cyclohexanone, tetrahydrofuran, dioxane, ethyl cellosolve, ethyl acetate, methyl acetate, dichloromethane, dichloroethane, monochlorobenzene, cyclohexane, toluene, xylene, ligroin and the like. As a method for applying the coating solution, a method such as a dip coating method, a spray coat, a beat coat, a nozzle coat, a spinner coat, and a ring coat can be used. The thickness of the charge generation layer (45) is suitably about 0.01 to 5 μm, and preferably 0.1 to 2 μm.

The charge transporting layer (47) can be formed by dissolving or dispersing the charge transporting substance and the binder resin in a suitable solvent, applying this on the charge generating layer, and drying. If necessary, a plasticizer, a leveling agent, an antioxidant and the like can be added.
The charge transport materials include a hole transport material and an electron transport material. Examples of the charge transport material include chloranil, bromanil, tetracyanoethylene, tetracyanoquinodimethane, 2,4,7-trinitro-9-fluorenone, 2,4,5,7-tetranitro-9-fluorenone, 2,4 , 5,7-Tetranitroxanthone, 2,4,8-trinitrothioxanthone, 2,6,8-trinitro-4H-indeno [1,2-b] thiophen-4-one, 1,3,7-trione Electron accepting substances such as nitrodibenzothiophene-5,5-dioxide, benzoquinone derivatives and the like.

Examples of the hole transport material include poly-N-vinylcarbazole and derivatives thereof, poly-γ-carbazolylethylglutamate and derivatives thereof, pyrene-formaldehyde condensate and derivatives thereof, polyvinylpyrene, polyvinylphenanthrene, polysilane, and oxazole derivatives. Oxadiazole derivative, imidazole derivative, monoarylamine derivative, diarylamine derivative, triarylamine derivative, stilbene derivative, α-phenylstilbene derivative, benzidine derivative, diarylmethane derivative, triarylmethane derivative, 9-styrylanthracene derivative, pyrazoline Derivatives, divinylbenzene derivatives, hydrazone derivatives, indene derivatives, butadiene derivatives, pyrene derivatives, etc., bisstilbene derivatives, enamine derivatives, etc. Other known materials can be used. These charge transport materials are used alone or in combination of two or more.

Examples of the binder resin include polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, and poly (vinyl acetate). Vinylidene chloride, polyalate, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly-N-vinyl carbazole, acrylic resin, silicone resin, epoxy resin, melamine resin, urethane resin, phenol resin And a thermoplastic or thermosetting resin such as an alkyd resin.
The amount of the charge transporting material is suitably 20 to 300 parts by weight, preferably 40 to 150 parts by weight, based on 100 parts by weight of the binder resin. Further, the thickness of the charge transport layer is preferably about 5 to 100 μm.
As the solvent used here, tetrahydrofuran, dioxane, toluene, dichloromethane, monochlorobenzene, dichloroethane, cyclohexanone, methyl ethyl ketone, acetone and the like are used. Among them, the use of a non-halogen solvent is desirable from the viewpoint of reducing the burden on the environment. Specifically, cyclic ethers such as tetrahydrofuran, dioxolan, and dioxane, aromatic hydrocarbons such as toluene and xylene, and derivatives thereof are preferably used.

に は In the charge transport layer, a polymer charge transport material having both a function as a charge transport material and a function as a binder resin is preferably used. The charge transport layer composed of these polymeric charge transport materials has excellent abrasion resistance. As the polymer charge transporting substance, known materials can be used, and particularly, a polycarbonate containing a triarylamine structure in a main chain and / or a side chain is preferably used. Among them, the polymer charge transport materials represented by the formulas (I) to (X) are preferably used, and these are exemplified below and specific examples are shown.

　式中、Ｒ_１、Ｒ_２、Ｒ_３はそれぞれ独立して置換もしくは無置換のアルキル基又はハロゲン原子、Ｒ_４は水素原子又は置換もしくは無置換のアルキル基、Ｒ_５、Ｒ_６は置換もしくは無置換のアリール基、ｏ、ｐ、ｑはそれぞれ独立して０〜４の整数、ｋ、ｊは組成を表わし、０．１≦ｋ≦１、０≦ｊ≦０．９、ｎは繰り返し単位数を表わし５〜５０００の整数である。Ｘは脂肪族の２価基、環状脂肪族の２価基、または下記一般式で表わされる２価基を表わす。なお、（Ｉ）式は２つの共重合種が交互共重合体の形で記載されているが、ランダム共重合体でも構わない。

In the formula, R ₁ , R ₂ , and R ₃ are each independently a substituted or unsubstituted alkyl group or a halogen atom, R ₄ is a hydrogen atom or a substituted or unsubstituted alkyl group, and R ₅ and R ₆ are substituted or unsubstituted. A substituted aryl group, o, p, and q each independently represent an integer of 0 to 4, k and j each represent a composition, 0.1 ≦ k ≦ 1, 0 ≦ j ≦ 0.9, and n represents the number of repeating units. And an integer of 5 to 5000. X represents an aliphatic divalent group, a cycloaliphatic divalent group, or a divalent group represented by the following general formula. In the formula (I), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.

　Ｒ_１０１、Ｒ_１０２は各々独立して置換もしくは無置換のアルキル基、アリール基またはハロゲン原子を表わす。ｌ、ｍは０〜４の整数、Ｙは単結合、炭素原子数１〜１２の直鎖状、分岐状もしくは環状のアルキレン基、−Ｏ−、−Ｓ−、−ＳＯ−、−ＳＯ_２−、−ＣＯ−、−ＣＯ−Ｏ−Ｚ−Ｏ−ＣＯ−（式中Ｚは脂肪族の２価基を表わす。）または、

R ₁₀₁ and R ₁₀₂ each independently represent a substituted or unsubstituted alkyl group, aryl group or halogen atom. l, m is an integer of 0 to 4, Y is a single bond, a linear C1-12, branched or cyclic alkylene group, -O -, - S -, - SO -, - SO 2 - , -CO-, -CO-O-Z-O-CO- (wherein Z represents an aliphatic divalent group) or

（ａは１〜２０の整数、ｂは１〜２０００の整数、Ｒ_１０３、Ｒ_１０４は置換または無置換のアルキル基又はアリール基を表わす）を表わす。ここで、Ｒ_１０１とＲ_１０２、Ｒ_１０３とＲ_１０４は、それぞれ同一でも異なってもよい。）

(A is an integer of 1 to 20, b is an integer of 1 to 2000, and R ₁₀₃ and R _{104 each} represent a substituted or unsubstituted alkyl group or aryl group). Here, R ₁₀₁ and R ₁₀₂ and R ₁₀₃ and R ₁₀₄ may be the same or different. )

　式中、Ｒ_７、Ｒ_８は置換もしくは無置換のアリール基、Ａｒ_１，Ａｒ_２，Ａｒ_３は同一又は異なるアリレン基を表わす。Ｘ，ｋ，ｊおよびｎは、（Ｉ）式の場合と同じである。なお、（II）式は２つの共重合種が交互共重合体の形で記載されているが、ランダム共重合体でも構わない。

In the formula, R ₇ and R ₈ represent a substituted or unsubstituted aryl group, and Ar ₁ , Ar ₂ , and Ar ₃ represent the same or different arylene groups. X, k, j and n are the same as in the case of the formula (I). In the formula (II), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.

　式中、Ｒ_９，Ｒ_１０は置換もしくは無置換のアリール基、Ａｒ_４，Ａｒ_５，Ａｒ_６は同一又は異なるアリレン基を表わす。Ｘ，ｋ，ｊおよびｎは、（Ｉ）式の場合と同じである。なお、（III）式は２つの共重合種が交互共重合体の形で記載されているが、ランダム共重合体でも構わない。

In the formula, R ₉ and R ₁₀ represent a substituted or unsubstituted aryl group, and Ar ₄ , Ar ₅ , and Ar ₆ represent the same or different arylene groups. X, k, j and n are the same as in the case of the formula (I). In the formula (III), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.

　式中、Ｒ_１１，Ｒ_１２は置換もしくは無置換のアリール基、Ａｒ_７，Ａｒ_８，Ａｒ_９は同一又は異なるアリレン基を表わす。Ｘ，ｋ，ｊおよびｎは、（Ｉ）式の場合と同じである。なお、（IV）式は２つの共重合種が交互共重合体の形で記載されているが、ランダム共重合体でも構わない。

In the formula, R ₁₁ and R ₁₂ represent a substituted or unsubstituted aryl group, and Ar ₇ , Ar ₈ , and Ar ₉ represent the same or different arylene groups. X, k, j and n are the same as in the case of the formula (I). In the formula (IV), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.

　式中、Ｒ_１３，Ｒ_１４は置換もしくは無置換のアリール基、Ａｒ_１０，Ａｒ_１１，Ａｒ_１２は同一又は異なるアリレン基、Ｘ_１，Ｘ_２は置換もしくは無置換のエチレン基、又は置換もしくは無置換のビニレン基を表わす。Ｘ，ｋ，ｊおよびｎは、（Ｉ）式の場合と同じである。なお、（Ｖ）式は２つの共重合種が交互共重合体の形で記載されているが、ランダム共重合体でも構わない。

In the formula, R ₁₃ and R ₁₄ are substituted or unsubstituted aryl groups, Ar ₁₀ , Ar ₁₁ , and Ar ₁₂ are the same or different arylene groups, X ₁ and X ₂ are substituted or unsubstituted ethylene groups, or substituted or unsubstituted. Represents a substituted vinylene group. X, k, j and n are the same as in the case of the formula (I). In addition, in the formula (V), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.

　式中、Ｒ_１５，Ｒ_１６，Ｒ_１７，Ｒ_１８は置換もしくは無置換のアリール基、Ａｒ_１３，Ａｒ_１４，Ａｒ_１５，Ａｒ_１６は同一又は異なるアリレン基、Ｙ_１，Ｙ_２，Ｙ_３は単結合、置換もしくは無置換のアルキレン基、置換もしくは無置換のシクロアルキレン基、置換もしくは無置換のアルキレンエーテル基、酸素原子、硫黄原子、ビニレン基を表わし同一であっても異なってもよい。Ｘ，ｋ，ｊおよびｎは、（Ｉ）式の場合と同じである。なお、（VI）式は２つの共重合種が交互共重合体の形で記載されているが、ランダム共重合体でも構わない。

In the formula, R ₁₅ , R ₁₆ , R ₁₇ , and R ₁₈ are substituted or unsubstituted aryl groups, Ar ₁₃ , Ar ₁₄ , Ar ₁₅ , and Ar ₁₆ are the same or different arylene groups, and Y ₁ , Y ₂ , and Y ₃ are A single bond, a substituted or unsubstituted alkylene group, a substituted or unsubstituted cycloalkylene group, a substituted or unsubstituted alkylene ether group, an oxygen atom, a sulfur atom, and a vinylene group may be the same or different. X, k, j and n are the same as in the case of the formula (I). In the formula (VI), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.

　式中、Ｒ_１９，Ｒ_２０は水素原子、置換もしくは無置換のアリール基を表わし，Ｒ_１９とＲ_２０は環を形成していてもよい。Ａｒ_１７，Ａｒ_１８，Ａｒ_１９は同一又は異なるアリレン基を表わす。Ｘ，ｋ，ｊおよびｎは、（Ｉ）式の場合と同じである。なお、（VII）式は２つの共重合種が交互共重合体の形で記載されているが、ランダム共重合体でも構わない。

In the formula, R ₁₉ and R _{20 each} represent a hydrogen atom or a substituted or unsubstituted aryl group, and R ₁₉ and R ₂₀ may form a ring. Ar ₁₇ , Ar ₁₈ and Ar ₁₉ represent the same or different arylene groups. X, k, j and n are the same as in the case of the formula (I). In the formula (VII), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.

　式中、Ｒ_２１は置換もしくは無置換のアリール基、Ａｒ_２０，Ａｒ_２１，Ａｒ_２２，Ａｒ_２３は同一又は異なるアリレン基を表わす。Ｘ，ｋ，ｊおよびｎは、（Ｉ）式の場合と同じである。なお、（VIII）式は２つの共重合種が交互共重合体の形で記載されているが、ランダム共重合体でも構わない。

In the formula, R ₂₁ represents a substituted or unsubstituted aryl group, and Ar ₂₀ , Ar ₂₁ , Ar ₂₂ , and Ar ₂₃ represent the same or different arylene groups. X, k, j and n are the same as in the case of the formula (I). In the formula (VIII), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.

　式中、Ｒ_２２，Ｒ_２３，Ｒ_２４，Ｒ_２５は置換もしくは無置換のアリール基、Ａｒ_２４，Ａｒ_２５，Ａｒ_２６，Ａｒ_２７，Ａｒ_２８は同一又は異なるアリレン基を表わす。Ｘ，ｋ，ｊおよびｎは、（Ｉ）式の場合と同じである。なお、（IX）式は２つの共重合種が交互共重合体の形で記載されているが、ランダム共重合体でも構わない。

In the formula, R ₂₂ , R ₂₃ , R ₂₄ , and R ₂₅ represent a substituted or unsubstituted aryl group, and Ar ₂₄ , Ar ₂₅ , Ar ₂₆ , Ar ₂₇ , and Ar ₂₈ represent the same or different arylene groups. X, k, j and n are the same as in the case of the formula (I). In the formula (IX), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.

　式中、Ｒ_２６，Ｒ_２７は置換もしくは無置換のアリール基、Ａｒ_２９，Ａｒ_３０，Ａｒ_３１は同一又は異なるアリレン基を表わす。Ｘ，ｋ，ｊおよびｎは、（Ｉ）式の場合と同じである。なお、（Ｘ）式は２つの共重合種が交互共重合体の形で記載されているが、ランダム共重合体でも構わない。

In the formula, R ₂₆ and R ₂₇ represent a substituted or unsubstituted aryl group, and Ar ₂₉ , Ar ₃₀ , and Ar ₃₁ represent the same or different arylene groups. X, k, j and n are the same as in the case of the formula (I). In the formula (X), two copolymer species are described in the form of an alternating copolymer, but a random copolymer may be used.

In addition, as the polymer charge transporting material used in the charge transporting layer, in addition to the above-described polymer charge transporting material, a monomer or oligomer having an electron donating group may be formed at the time of film formation of the charge transporting layer. A polymer having a two-dimensional or three-dimensional crosslinked structure is finally included by a curing reaction or a crosslinking reaction.

(4) The charge transport layer composed of the polymer having an electron donating group or the polymer having a crosslinked structure has excellent abrasion resistance. Normally, in an electrophotographic process, the charging potential (potential of an unexposed portion) is constant. Therefore, when the surface layer of the photoreceptor is worn by repeated use, the electric field intensity applied to the photoreceptor increases by that much. As the electric field intensity increases, the frequency of occurrence of background contamination increases. Therefore, the high wear resistance of the photoconductor is advantageous against background contamination. The charge transport layer composed of a polymer having these electron donating groups is excellent in film-forming properties because it is a polymer compound itself, and has a charge transport site as compared with the charge transport layer composed of a low molecular weight dispersed polymer. It can be formed at high density and has excellent charge transporting ability. Therefore, a high-speed response can be expected for a photoreceptor having a charge transport layer using a polymer charge transport material.

Other polymers having an electron donating group include copolymers of known monomers, block polymers, graft polymers, star polymers, and, for example, JP-A-3-109406, JP-A-2000- It is also possible to use a crosslinked polymer having an electron donating group as disclosed in JP-A-206723, JP-A-2001-34001 and the like. Also in this case, a material that can satisfy the above mobility can be effectively used.

に お い て In the present invention, a plasticizer or a leveling agent may be added to the charge transport layer (47). As the plasticizer, those used as plasticizers for general resins such as dibutyl phthalate and dioctyl phthalate can be used as they are, and the amount of the plasticizer is suitably about 0 to 30% by weight based on the binder resin. As the leveling agent, silicone oils such as dimethyl silicone oil and methylphenyl silicone oil, and polymers or oligomers having a perfluoroalkyl group in a side chain are used. 1% by weight is suitable.

中間 In the electrophotographic photoreceptor of the present invention, an intermediate layer can be provided between the conductive support (41) and the photosensitive layer. The intermediate layer generally contains a resin as a main component. However, considering that these resins are coated on the photosensitive layer with a solvent, it is preferable that the resin be a resin having high solvent resistance to general organic solvents. . Examples of such a resin include water-soluble resins such as polyvinyl alcohol, casein, and sodium polyacrylate, alcohol-soluble resins such as copolymerized nylon and methoxymethylated nylon, polyurethane, melamine resins, phenol resins, alkyd-melamine resins, and epoxy resins. Curable resins that form a three-dimensional network structure, such as resins, are exemplified. Further, a fine powder pigment of a metal oxide exemplified by titanium oxide, silica, alumina, zirconium oxide, tin oxide, indium oxide or the like may be added to the intermediate layer in order to prevent moire and reduce residual potential.

These intermediate layers can be formed using an appropriate solvent and a coating method as in the above-described photosensitive layer. Further, a silane coupling agent, a titanium coupling agent, a chromium coupling agent, or the like can be used as the intermediate layer of the present invention. In addition, the intermediate layer according to the present invention includes a layer provided with Al ₂ O ₃ by anodization, an organic substance such as polyparaxylylene (parylene), SiO ₂ , SnO ₂ , TiO ₂ , ITO, CeO _{2 and the} like. An inorganic material provided by a vacuum thin film forming method can also be used favorably. In addition, known materials can be used. The thickness of the intermediate layer is suitably from 0 to 5 μm.

In the electrophotographic photoreceptor of the present invention, a protective layer may be provided on the photosensitive layer for the purpose of protecting the photosensitive layer. 2. Description of the Related Art In recent years, computers have been used on a daily basis, and high-speed output by a printer and a small-sized apparatus have been desired. Therefore, by providing a protective layer and improving the durability, the photoconductor of the present invention having high sensitivity and free from abnormal defects can be used effectively.
Materials used for the protective layer (49) include ABS resin, ACS resin, olefin-vinyl monomer copolymer, chlorinated polyether, allyl resin, phenol resin, polyacetal, polyamide, polyamideimide, polyacrylate, and polyallyl sulfone. , Polybutylene, polybutylene terephthalate, polycarbonate, polyarylate, polyether sulfone, polyethylene, polyethylene terephthalate, polyimide, acrylic resin, polymethylbenten, polypropylene, polyphenylene oxide, polysulfone, polystyrene, AS resin, butadiene-styrene copolymer, polyurethane And resins such as polyvinyl chloride, polyvinylidene chloride, and epoxy resin. Among them, polycarbonate or polyarylate can be most preferably used.

The protective layer (49) further includes a fluorine resin such as polytetrafluoroethylene, a silicone resin, and an inorganic filler such as titanium oxide, tin oxide, potassium titanate, and silica for the purpose of improving abrasion resistance. Further, a dispersion of an organic filler or the like can be added.
Further, among the filler materials used for the protective layer of the photoreceptor, examples of the organic filler material include fluororesin powder such as polytetrafluoroethylene, silicone resin powder, a-carbon powder, and the like. Are metal powders such as copper, tin, aluminum and indium, silica, tin oxide, zinc oxide, titanium oxide, indium oxide, antimony oxide, bismuth oxide, tin oxide doped with antimony, indium oxide doped with tin, etc. And inorganic materials such as potassium titanate. Particularly, from the viewpoint of the hardness of the filler, it is advantageous to use an inorganic material among them. In particular, silica, titanium oxide, and alumina can be effectively used.

The filler concentration in the protective layer varies depending on the type of filler used and the electrophotographic process conditions using the photoreceptor, but is 5% by weight or more, preferably 5% by weight or more, based on the total solids on the outermost layer side of the protective layer. 10% by weight or more and 50% by weight or less, preferably about 30% by weight or less are good.
The volume average particle diameter of the filler to be used is preferably 0.1 μm to 2 μm, and more preferably 0.3 μm to 1 μm. In this case, if the average particle size is too small, the abrasion resistance is not sufficiently exhibited, and if the average particle size is too large, the surface properties of the coating film deteriorate, or the coating film itself cannot be formed.

The average particle size of the filler in the present invention is a volume average particle size unless otherwise specified, and is determined by an ultracentrifugal automatic particle size distribution analyzer: CAPA-700 (manufactured by Horiba, Ltd.). In this case, the particle diameter was calculated as a particle diameter (Median type) corresponding to 50% of the cumulative distribution. It is important that the standard deviation of each particle measured at the same time is 1 μm or less. If the value of the standard deviation is larger than this, the effect of the present invention may not be obtained remarkably because the particle size distribution is too wide.

Further, the pH of the filler used in the present invention greatly affects the resolution and the dispersibility of the filler. As one of the reasons, it is considered that hydrochloric acid or the like remains during the production of fillers, especially metal oxides. When the residual amount is large, the occurrence of image blur is inevitable, and depending on the residual amount, it may affect the dispersibility of the filler.
Another reason is that the chargeability on the surface of the filler, especially the metal oxide, is different. Normally, particles dispersed in a liquid are positively or negatively charged, and ions having the opposite charge gather in an attempt to keep it electrically neutral, where an electric double layer is formed. The dispersion state of the particles is stabilized. As the distance from the particle increases, its potential (zeta potential) gradually decreases, and the potential of a region sufficiently far from the particle and electrically neutral becomes zero. Therefore, the stability increases as the repulsive force of the particles increases due to an increase in the absolute value of the zeta potential, and the particles tend to aggregate and become unstable as the value approaches zero.
On the other hand, the zeta potential varies greatly depending on the pH value of the system, and at a certain pH value, the potential becomes zero and has an isoelectric point. Therefore, the dispersion system is stabilized by increasing the absolute value of the zeta potential as far as possible from the isoelectric point of the system.
In the constitution of the present invention, as the filler, those having a pH at the above-mentioned isoelectric point of at least 5 are preferable from the viewpoint of suppressing image blur, and the more the filler is more basic, the higher the effect tends to be. It was confirmed that there was. The filler having a high pH at the isoelectric point and exhibiting a basic property has a higher zeta potential when the system is acidic, so that the dispersibility and the stability thereof are improved.
Here, the pH of the filler in the present invention is a pH value at the isoelectric point from the zeta potential. At this time, the zeta potential was measured with a laser zeta potentiometer manufactured by Otsuka Electronics Co., Ltd.

Further, as a filler that is unlikely to cause image blur, a filler having high electric insulation (specific resistance of 10 ¹⁰ Ω · cm or more) is preferable, and a filler having a pH of 5 or more and a dielectric constant of 5 or more are preferable. The ones shown can be used particularly effectively. In addition, a filler having a pH of 5 or more or a filler having a dielectric constant of 5 or more may be used alone, or a mixture of two or more fillers having a pH of 5 or less and a filler having a pH of 5 or more may be used. It is also possible to use a mixture of two or more fillers having a dielectric constant of 5 or less and a filler having a dielectric constant of 5 or more. Among these fillers, α-alumina, which has high insulation properties, high thermal stability, and high hexagonal close-packed structure with high abrasion resistance, suppresses image blur and improves abrasion resistance. Particularly useful from.

The specific resistance of the filler used in the present invention is defined as follows. Since the specific resistance of a powder such as a filler differs depending on the filling rate, it is necessary to measure the powder under a certain condition. In the present invention, the specific resistance of the filler is measured using an apparatus having the same configuration as the measuring apparatus disclosed in JP-A-5-94049 (FIG. 1) and JP-A-5-113688 (FIG. 1). The value was measured and used. In the measuring device, the electrode area is 4.0 cm ² . Before the measurement, a load of 4 kg is applied to one electrode on one side for 1 minute, and the amount of the sample is adjusted so that the distance between the electrodes becomes 4 mm. At the time of the measurement, the measurement is performed under a load state of the weight (1 kg) of the upper electrode, and the applied voltage is measured at 100V. The area of 10 ⁶ Ω · cm or more was measured with a HIGH RESISTANCE METER (Yokogawa Hewlett-Packard), and the area below 10 ⁶ Ω · cm was measured with a digital multimeter (Fluke). The specific resistance value thus obtained is defined as the specific resistance value according to the present invention.

誘 電 The dielectric constant of the filler was measured as follows. After applying a load using the same cell as that for measuring the specific resistance as described above, the capacitance was measured, and the dielectric constant was determined from this. The capacitance was measured using a dielectric loss meter (Ando Electric).

Furthermore, these fillers can be surface-treated with at least one surface treatment agent, and it is preferable to do so from the viewpoint of filler dispersibility. A decrease in the dispersibility of the filler not only increases the residual potential but also causes a decrease in the transparency of the coating film, the occurrence of coating film defects, and a decrease in abrasion resistance, which hinders high durability or high image quality. It can evolve into a big problem. As the surface treatment agent, all the surface treatment agents conventionally used can be used, but a surface treatment agent capable of maintaining the insulating property of the filler is preferable. For example, titanate-based coupling agents, aluminum-based coupling agents, zirco-aluminate-based coupling agents, higher fatty acids, or the like, or a mixture treatment thereof with a silane coupling agent, Al ₂ O ₃ , TiO ₂ , ZrO ₂ , Silicone, aluminum stearate, or the like, or a mixture thereof is more preferable from the viewpoint of filler dispersibility and image blur. Although the treatment with the silane coupling agent has a strong effect of image blur, the effect of mixing the surface treatment agent and the silane coupling agent may be suppressed in some cases. Although the surface treatment amount varies depending on the average primary particle size of the filler used, 3 to 30 wt% is suitable, and 5 to 20 wt% is more preferable. If the amount of the surface treatment is smaller than this, the effect of dispersing the filler cannot be obtained, and if the amount is too large, the residual potential is significantly increased. These filler materials are used alone or in combination of two or more. The surface treatment amount of the filler is defined by the weight ratio of the surface treatment agent used to the filler amount as described above.
These filler materials can be dispersed by using an appropriate disperser. Further, from the viewpoint of the transmittance of the protective layer, it is preferable that the filler used is dispersed to the level of the primary particles and the amount of the aggregate is small.

Further, the protective layer (49) may contain a charge transporting substance for reducing the residual potential and improving the response. As the charge transporting substance, the materials described in the description of the charge transporting layer can be used. When a low molecular charge transport material is used as the charge transport material, a concentration gradient in the protective layer may be provided. It is an effective means to reduce the concentration on the surface side in order to improve abrasion resistance. The concentration here refers to the ratio of the weight of the low-molecular charge transporting substance to the total weight of all the materials constituting the protective layer, and the concentration gradient is such that the concentration becomes lower on the surface side at the above weight ratio. It indicates that. The use of a charge transport polymer is very advantageous in that the durability of the photoreceptor is improved.
An ordinary coating method is adopted as a method for forming the protective layer. The thickness of the protective layer is suitably about 0.1 to 10 μm. In addition, other known materials such as aC and a-SiC formed by a vacuum thin film forming method can be used as the protective layer.
As described above, the use of a polymeric charge transport material in the photosensitive layer (charge transport layer) or the provision of a protective layer on the surface of the photoconductor increases the durability (wear resistance) of each photoconductor. In addition, when used in a tandem-type full-color image forming apparatus, it produces a new effect that is not provided by a monochrome image forming apparatus.
In the case of a full-color image, various types of images are input. On the contrary, a standard image may be input. For example, the presence of a seal in a Japanese document or the like. Something like a stamp is usually located near the edge of the image area, and the colors used are also limited. In a state where a random image is always written, image writing, development and transfer are performed on the photoreceptor in the image forming element on average. When a large number of image formations are repeated or when only a specific image formation element is used, the durability of the image formation element is not balanced. When a photoreceptor having a small surface durability (physical, chemical, mechanical) is used in such a state, the difference becomes remarkable, which tends to cause an image problem. On the other hand, when the photoreceptor is made highly durable, such a local change amount is small, and as a result, it is difficult to appear as a defect on an image. It is also very effective.

Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited by the examples. All parts are parts by weight.

First, a synthesis example of a titanyl phthalocyanine crystal (hereinafter, sometimes referred to as a pigment) used in the present invention will be described.
(Synthesis example 1)
29.2 g of 1,3-diiminoisoindoline and 200 ml of sulfolane are mixed, and 20.4 g of titanium tetrabutoxide is added dropwise under a nitrogen stream. After completion of the dropwise addition, the temperature was gradually raised to 180 ° C, and the reaction was carried out with stirring for 5 hours while maintaining the reaction temperature between 170 ° C and 180 ° C. After the reaction, the precipitate was filtered after standing to cool, washed with chloroform until the powder turned blue, then washed with methanol several times, further washed with hot water of 80 ° C. several times, and dried. Crude titanyl phthalocyanine was obtained. The crude titanyl phthalocyanine is dissolved in 20 times the volume of concentrated sulfuric acid, dropped into 100 volumes of the ice water with stirring, and the precipitated crystals are filtered. Got. 2 g of the obtained wet cake was put into 20 g of tetrahydrofuran, stirred for 4 hours, filtered, and dried to obtain titanyl phthalocyanine crystal.
Further, 30 g of the titanyl phthalocyanine crystal was immersed in 300 g of tetrahydrofuran to perform a second crystal conversion. After immersion and standing for 12 hours, the mixture was separated by filtration, and dried under reduced pressure under the same conditions as above to obtain a titanyl phthalocyanine crystal used in the present invention. This is referred to as Pigment 1.

(Synthesis example 2)
The same procedure as in Synthesis Example 1 was carried out, except that the second crystal conversion operation in Synthesis Example 1 was changed to the following conditions, to obtain a titanyl phthalocyanine crystal of the present invention. This is designated as Pigment 2.
(Second crystal conversion process)
30 g of the titanyl phthalocyanine crystal subjected to the first crystal conversion treatment was subjected to mechanical shearing force for 5 minutes by a commercially available mixer, and then the powder was taken out.

(Synthesis example 3)
The same procedure as in Synthesis Example 1 was carried out, except that the second crystal conversion operation in Synthesis Example 1 was changed to the following conditions, to obtain a titanyl phthalocyanine crystal of the present invention. This is designated as Pigment 3.
(Second crystal conversion process)
30 g of the titanyl phthalocyanine crystal subjected to the first crystal conversion treatment was put into a φ90 mm glass pot together with 2 kg of φ6 mm zirconia balls, and after dry milling was performed for 10 minutes, the powder was taken out.

(Comparative Synthesis Example 1)
The same procedure as in Synthesis Example 1 was carried out except that the second crystal conversion solvent in Synthesis Example 1 was changed from tetrahydrofuran to 2-butanone, to obtain a titanyl phthalocyanine crystal of the present invention. This is designated as Pigment 4.

(Comparative Synthesis Example 2)
In Synthesis Example 1, the same treatment as in Synthesis Example 1 was performed, except that 2-butanone was used instead of tetrahydrofuran as the first crystal conversion solvent and the second crystal conversion was not performed, to obtain titanyl phthalocyanine crystals. . This is designated as Pigment 5.

A part of the water paste obtained in Synthesis Example 1 was dried at 80 ° C. under reduced pressure (5 mmHg) for 2 days to obtain low crystalline titanyl phthalocyanine powder.
The X-ray diffraction spectra of the dried powder of the water paste obtained as described above and the titanyl phthalocyanine crystals obtained in Synthesis Examples 1 to 3 and Comparative Synthesis Examples 1 and 2 were measured under the following conditions. FIG. 9 shows the X-ray diffraction spectrum of the dried powder of the water paste.
X-ray tube: Cu
Voltage: 40kV
Current: 20mA
Scanning speed: 1 ° / min Scanning range: 3 ° to 40 °
Time constant: 2 seconds

Regarding Synthesis Examples 1 to 3, the same X-ray diffraction spectrum was shown in each case except for the peak intensity at 26.3 °. Therefore, as a representative example, the X-ray diffraction of the titanyl phthalocyanine crystal obtained in Synthesis Example 2 was obtained. The spectrum is shown in FIG. 10 (the arrow in the figure is the peak at 26.3 °, and the peak intensity ratio is 8%).
An X-ray diffraction spectrum of the titanyl phthalocyanine crystal obtained in Comparative Synthesis Example 1 is shown in FIG. 11, but showed no peak at 26.3 °.
FIG. 12 shows an X-ray diffraction spectrum of the titanyl phthalocyanine crystal obtained in Comparative Synthesis Example 2. The X-ray diffraction spectrum had a minimum angle of 7.5 °.

(Comparative Synthesis Example 3)
A pigment was prepared according to the method described in JP-A-1-299874 (Japanese Patent No. 2512081) and Example 1. That is, the wet cake prepared in Synthesis Example 1 was dried, 1 g of the dried product was added to 50 g of polyethylene glycol, and a sand mill was performed together with 100 g of glass beads. After the crystal transition, the resultant was washed with dilute sulfuric acid and an aqueous solution of ammonium hydroxide in that order and dried to obtain a pigment. This is designated as Pigment 6.

(Comparative Synthesis Example 4)
A pigment was prepared according to the method described in Production Example 1 of JP-A-3-269064 (Japanese Patent No. 2584682). That is, the wet cake prepared in Synthesis Example 1 was dried, and 1 g of the dried product was stirred (50 ° C.) for 1 hour in a mixed solvent of 10 g of ion-exchanged water and 1 g of monochlorobenzene, and then washed with methanol and ion-exchanged water. And dried to obtain a pigment. This is designated as Pigment 7.

(Comparative Synthesis Example 5)
A pigment was prepared according to the method described in the production example of JP-A-2-8256 (JP-B-7-91486). That is, 9.8 g of phthalodinitrile and 75 ml of 1-chloronaphthalene are stirred and mixed, and 2.2 ml of titanium tetrachloride is added dropwise under a nitrogen stream. After the completion of the dropwise addition, the temperature was gradually raised to 200 ° C, and the reaction was carried out with stirring for 3 hours while maintaining the reaction temperature between 200 ° C and 220 ° C. After the completion of the reaction, the mixture was allowed to cool to 130 ° C., filtered while hot, then washed with 1-chloronaphthalene until the powder turned blue, washed several times with methanol, and further washed with hot water at 80 ° C. After washing twice, it was dried to obtain a pigment. This is designated as Pigment 8.

(Comparative Synthesis Example 6)
A pigment was prepared according to the method described in JP-A No. 64-17066 (JP-B-7-97221) and Synthesis Example 1. That is, 5 parts of α-type TiOPc was subjected to a crystal conversion treatment at 100 ° C. for 10 hours with a sand grinder together with 10 g of sodium chloride and 5 g of acetophenone. This was washed with ion-exchanged water and methanol, purified with a dilute aqueous sulfuric acid solution, washed with ion-exchanged water until the acid content disappeared, and then dried to obtain a pigment. This is referred to as Pigment 9.

(Comparative Synthesis Example 7)
A pigment was prepared according to the method described in JP-A-11-5919 (Japanese Patent No. 3003664) and Example 1. That is, after 20.4 parts of O-phthalodinitrile and 7.6 parts of titanium tetrachloride were heated and reacted in 50 parts of quinoline at 200 ° C. for 2 hours, the solvent was removed by steam distillation, followed by a 2% aqueous chloride solution, The product was purified with a 2% aqueous sodium hydroxide solution, washed with methanol and N, N-dimethylformamide, and dried to obtain titanyl phthalocyanine. 2 parts of this titanyl phthalocyanine is dissolved little by little in 40 parts of 98% sulfuric acid at 5 ° C., and the mixture is stirred for about 1 hour while maintaining the temperature at 5 ° C. or less. Subsequently, the sulfuric acid solution is slowly poured into 400 parts of ice water with high-speed stirring, and the precipitated crystals are filtered. The crystals are washed with distilled water until no acid remains, to obtain a wet cake. The cake was stirred in 100 parts of THF for about 5 hours, filtered, washed with THF and dried to obtain a pigment. This is designated as Pigment 10.

(Comparative Synthesis Example 8)
A pigment was prepared according to the method described in JP-A-3-255456 (Japanese Patent No. 3005052) and Synthesis Example 2. That is, 10 parts of the wet cake prepared in Synthesis Example 1 described above was mixed with 15 parts of sodium chloride and 7 parts of diethylene glycol, and milling was performed for 60 hours in an automatic mortar under heating at 80 ° C. Next, the treated product was sufficiently washed with water to completely remove sodium chloride and diethylene glycol. After drying under reduced pressure, 200 parts of cyclohexanone and glass beads having a diameter of 1 mm were added, and the mixture was treated by a sand mill for 30 minutes to obtain a pigment. This is designated as Pigment 11.

(Comparative Synthesis Example 9)
A pigment was produced according to the method described in JP-A-11-5919 (Japanese Patent No. 3003664) and Example 4. That is, the wet cake obtained in Comparative Synthesis Example 7 was washed with 5% hydrochloric acid, washed with water until neutral, filtered, and dried. This was further dispersed in a ball mill for 10 hours together with THF, filtered and dried to obtain a pigment powder. This is designated as Pigment 12.

(Comparative Synthesis Example 10)
Pigments were prepared according to the methods described in JP-A-5-134337 (Japanese Patent No. 3196260), Production Examples 1 and 2.
That is, 97.5 g of phthalodinitrile is added to 750 ml of α-chloronaphthalene, and then 22 ml of titanium tetrachloride is added dropwise under a nitrogen atmosphere. After the dropwise addition, the temperature was raised, and the mixture was reacted at 200 to 220 ° C. for 3 hours with stirring, then allowed to cool, filtered while hot at 100 to 130 ° C., and washed with 200 ml of α-chloronaphthalene heated to 100 ° C. Further, hot suspension washing (100 ° C., 1 hour) was performed three times with 200 ml of N-methylpyrrolidone. Subsequently, the resultant was washed with 300 ml of methanol at room temperature and further washed three times with 500 ml of methanol for 1 hour. This is designated as phthalocyanine 1.
Next, the phthalocyanine 1 was ground by a sand grind mill for 20 hours, then put into a suspension of 400 ml of water and 40 ml of o-dichlorobenzene, and heated at 60 ° C. for 1 hour. This is designated as phthalocyanine 2.
Further, according to Example 1 of JP-A-5-134337, 6 parts by weight and 4 parts by weight of phthalocyanine 1 and phthalocyanine 2 were mixed, 200 parts by weight of n-propanol were added, and the mixture was pulverized with a sand grind mill for 10 hours. A micronized dispersion treatment was performed. This was dried to obtain a phthalocyanine powder. This is referred to as pigment 13.

(Synthesis example 4)
292 parts of 1,3-diiminoisoindoline and 1800 parts of sulfolane are mixed, and 204 parts of titanium tetrabutoxide are added dropwise under a nitrogen stream. After completion of the dropwise addition, the temperature was gradually raised to 180 ° C, and the reaction was carried out with stirring for 5 hours while maintaining the reaction temperature between 170 ° C and 180 ° C. After the reaction, the precipitate was filtered after standing to cool, washed with chloroform until the powder turned blue, then washed with methanol several times, further washed with hot water of 80 ° C. several times, and dried. Crude titanyl phthalocyanine was obtained. Sixty parts of the obtained crude titanyl phthalocyanine pigment subjected to the washing with hot water were stirred and dissolved in 1,000 parts of 96% sulfuric acid at 3 to 5 ° C. and filtered. The obtained sulfuric acid solution was dropped into 35,000 parts of ice water while stirring, and the precipitated crystals were filtered and then washed repeatedly with water until the washing liquid became neutral, to obtain a water paste of titanyl phthalocyanine pigment.
1500 parts of tetrahydrofuran was added to this water paste, and the mixture was vigorously stirred (2000 rpm) with a homomixer (Kennis, MARK, f model) at room temperature. Min), stirring was stopped, and filtration under reduced pressure was immediately performed. The crystals obtained on the filter were washed with tetrahydrofuran to obtain 98 parts of a pigment wet cake. This was dried at 70 ° C. under reduced pressure (5 mmHg) for 2 days to obtain 78 parts of titanyl phthalocyanine crystals. Further, 30 g of the titanyl phthalocyanine crystal was immersed in 300 g of tetrahydrofuran to perform a second crystal conversion. After immersion and standing for 12 hours, the mixture was separated by filtration, and dried under reduced pressure under the same conditions as above to obtain a titanyl phthalocyanine crystal used in the present invention. This is referred to as pigment 14.

X-ray diffraction spectra of the pigments prepared in Comparative Synthesis Examples 3 to 10 were measured by the same method as described above, and it was confirmed that the spectra were the same as those described in the respective publications. Table 1 shows the characteristics of the X-ray diffraction spectra and the peak positions of the X-ray diffraction spectra of the pigments obtained in Synthesis Examples 1 to 4 and Comparative Synthesis Examples 1 to 10.
The peak intensity at 26.3 ° in Table 1 is the ratio of the peak intensity at 27.3 ° to the peak intensity at 26.3 ° as described above. In this calculation, when the peak at 26.3 ° was not clearly observed as shown in FIG. 10, the calculation was performed with the peak intensity = 0.

(Photoconductor production example 1)
An undercoat layer coating solution, a charge generation layer coating solution, and a charge transport layer coating solution having the following compositions are sequentially applied to an aluminum cylinder (JIS 1050) having a diameter of 60 mm and dried, and a 3.5 μm undercoat layer is formed. A charge generating layer and a 25 μm charge transporting layer were formed to produce a laminated photoreceptor (referred to as photoreceptor 1). The thickness of the charge generation layer was adjusted so that the transmittance of the charge generation layer at 780 nm was 20%. The transmittance of the charge generation layer was determined by applying a charge generation layer coating solution having the following composition to an aluminum cylinder around which a polyethylene terephthalate film was wound under the same conditions as in the preparation of the photoreceptor. The polyethylene terephthalate film was not used, and the transmittance at 780 nm was evaluated using a commercially available spectrophotometer (Shimadzu: UV-3100).

◎ Undercoat layer coating liquid Titanium oxide (CR-EL: manufactured by Ishihara Sangyo Co., Ltd.) 70 parts Alkyd resin 15 parts (Beccolite M6401-50-S (solid content 50%),
Dainippon Ink and Chemicals)
Melamine resin 10 parts (Super Beckamine L-121-60 (solid content 60%),
Dainippon Ink and Chemicals)
2-butanone 100 parts

A charge generation layer coating solution A dispersion having the following composition was prepared by bead milling under the following conditions.
Pigment 1 15 parts Polyvinyl butyral (manufactured by Sekisui Chemical: BX-1) 10 parts 2-butanone 280 parts Using a 0.5 mm diameter PSZ ball in a commercially available bead mill disperser, dissolve polyvinyl butyral and all 2-butanone and pigment. And the rotor rotation speed 1500r. p. m. For 30 minutes to prepare a dispersion.
The titanyl phthalocyanine crystal particle size in the prepared dispersion was measured with a Horiba, Ltd .: CAPA-700. As a result, the average particle size was 0.24 μm.
◎ Coating solution for charge transport layer 10 parts polycarbonate (TS2050: manufactured by Teijin Chemicals Ltd .: viscosity average molecular weight is about 50,000)
7 parts of charge transport material of the following structural formula

　　塩化メチレン　　　　　　　　　　　　　　　　　　　　　　　８０部

80 parts of methylene chloride

(Photoreceptor Production Examples 2 to 13)
The titanyl phthalocyanine pigment (pigment 1) used in the charge generation layer coating liquid used in photoreceptor preparation example 1 was prepared in each of Synthesis Examples 2 to 3 (Pigments 2 to 3) and Comparative Synthesis Examples 1 to 10 (Pigments 2 to 13). ), Except that the titanyl phthalocyanine pigment prepared in (1) was used. The thickness of the charge generation layer was adjusted so that the transmittance at 780 nm was 20% when all the coating liquids were used, as in Photoconductor Preparation Example 1.
The average particle size of the charge generation layer coating solution used in Photoconductor Preparation Examples 2 to 13 was measured by Horiba, Ltd .: CAPA-700 in the same manner as above. As a result, the average particle size of each coating liquid was as follows.
Production Example 2: 0.23 μm
Production Example 3: 0.24 μm
Production Example 4: 0.24 μm
Production Example 5: 0.25 μm
Production Example 6: 0.26 μm
Production Example 7: 0.30 μm
Production Example 8: 0.28 μm
Production Example 9: 0.24 μm
Production Example 10: 0.27 μm
Production Example 11: 0.24 μm
Production Example 12: 0.28 μm
Production Example 13: 0.26 μm

(Examples 1 to 3 and Comparative Examples 1 to 23)
The electrophotographic photoreceptors of Photoreceptor Production Examples 1 to 13 produced as described above are mounted on the electrophotographic apparatus shown in FIG. 1 (150 msec between exposure and development), and an image exposure light source is a 780 nm semiconductor laser (polygon laser). As an image writing with a mirror), writing is performed at a resolution of 600 dpi, and a charging roller of a non-contact proximity charging type as shown in FIG. 2 (with an insulating tape having a thickness of 50 μm wrapped at both ends) as shown in FIG. Under the following charging and exposure conditions, a one-dot line image and a solid image were output. At the same time, in order to measure the surface potential (unexposed area and image exposed area) of the photoreceptor at the developing section position, a photosensitive jig is used to set the electrometer at the position where the developing device is mounted. Body surface potential was measured. In the measurement of the exposed portion potential, the surface potential when solid writing was performed with a predetermined light amount was measured (the evaluation environment was 23 ° C.-55% RH). Table 2 shows the above results.
Charging conditions:
DC bias: -900V
AC bias: 2.0 kV (peak to peak)
Frequency: 1.5kHz
Image exposure conditions:
The exposure energy on the photoreceptor surface is 4.5 erg. / Cm ² , 6.0 erg. / Cm ²

From the results in Table 2, the exposed portion potentials of the photoreceptors prepared in Photoreceptor Preparation Examples 6 to 13 were higher when the exposure amount was 4.5 erg / cm ² , and the image density was lower. . By setting this to an exposure amount of 6.0 erg / cm ² , a decrease in the potential of the exposed portion was recognized, and a decrease in image density was resolved, but line thickening occurred.
In the case of using a photosensitive member prepared in photosensitive member Production Example 1-5, was forming a good image in the case of exposure 4.5erg / cm ^2, the exposure amount 6.0erg / cm ² In some cases, line thickening occurred.

(Examples 4 to 6 and Comparative Examples 24 to 33)
The photoreceptors produced in Photoreceptor Production Examples 1 to 14 were mounted on the same apparatus as in Example 1, and 30,000 sheets of images were output. The charging conditions were the same as in Example 1, but the exposure conditions were 4.5 erg. / Cm ² only. The output image is a chart with a writing rate of 6%. Also, a white solid image was output at the initial stage and after 30,000 copies were run, and the stain on the background portion was evaluated as a rank. Furthermore, the surface potential of the unexposed portion and the exposed portion of the photoreceptor was measured by the same method as in Example 1 at the initial stage and after 30,000 copies were run. These evaluations were performed in three environments of 22 ° C.-55% RH, 10 ° C.-15% RH, and 30 ° C.-90% RH. Table 3 shows the results.
Evaluation result under 22 ° C-55% RH environment

地汚れランク：
　　５：地汚れほとんどなし、
　　４：わずかにあり、
　　３：実使用限界レベル、
　　２以下：実使用には耐えないレベル
　１０℃−１５％ＲＨ環境下での評価結果

Ground dirt rank:
5: Almost no dirt,
4: Slightly
3: Actual use limit level,
2 or less: Level that does not endure actual use Evaluation result under 10 ° C-15% RH environment

　３０℃−９０％ＲＨ環境下での評価結果

Evaluation result under 30 ° C-90% RH environment

As described above, from the results in Table 3, it is understood that when the photoconductors of Photoconductor Production Examples 1 to 3 are used, a stable surface potential is maintained in all three environments, and a formed image is also good. In the case of using the photoreceptor manufactured in Photoreceptor Production Example 2, the exposed portion potential is slightly higher in the case of Photoreceptor Preparation Example 2 than in the case of using Photoreceptor Preparation Examples 1 and 3. You can see that.
On the other hand, when the photoreceptor preparation examples 4 and 5 are used, it can be seen that the potential fluctuation amount under high temperature and high humidity, low temperature and low humidity is large, and the background stain under high temperature and high humidity is poor. Also, when the photoreceptors of Photoreceptor Production Examples 6 to 10 were used, the exposed portion potential was high, and the potential stability in three environments and the soiling property were poor. It can be seen that when the photoreceptors of Photoreceptor Production Examples 11 to 13 were used, the exposed portion potential was clearly higher and the potential stability in three environments was inferior as compared with the other cases.

(Photoconductor Production Example 14)
A photoconductor was prepared in the same manner as in Photoconductor Preparation Example 1, except that the coating liquid for the charge transport layer in Photoconductor Preparation Example 1 was changed to one having the following composition.
◎ Coating solution for charge transport layer 10 parts of polymer charge transport material having the following composition (weight average molecular weight: about 140,000)

　　下記構造の添加剤　　　　　　　　　　　　　　０．５部

0.5 parts of additives having the following structure

　　塩化メチレン　　　　　　　　　　　　　　　　１００部

100 parts of methylene chloride

(Photoconductor Production Example 15)
Same as Photoreceptor Preparation Example 1 except that the thickness of the charge transport layer in Photoreceptor Preparation Example 1 was set to 20 μm, a protective layer coating solution having the following composition was applied and dried on the charge transport layer, and a protective layer of 5 μm was provided. A photosensitive member was prepared.
◎ Coating solution for protective layer: 10 parts of polycarbonate (TS2050: manufactured by Teijin Chemicals Limited; viscosity average molecular weight is about 50,000)
7 parts of charge transport material of the following structural formula

　　アルミナ微粒子　　　　　　　　　　　　　　　　　　　　　　４部
　　　（比抵抗：２．５×１０１２Ω・ｃｍ、平均一次粒径：０．４μｍ）
　　シクロヘキサノン　　　　　　　　　　　　　　　　　　　５００部
　　テトラヒドロフラン　　　　　　　　　　　　　　　　　　１５０部

4 parts of alumina fine particles (specific resistance: 2.5 × 10 12 Ω · cm, average primary particle size: 0.4 μm)
Cyclohexanone 500 parts Tetrahydrofuran 150 parts

(Photoconductor Production Example 16)
A photoconductor was prepared in the same manner as in Photoconductor Preparation Example 15, except that the alumina fine particles in the protective layer coating liquid in Photoconductor Preparation Example 15 were changed to the following.
4 parts of titanium oxide fine particles (specific resistance: 1.5 × 10 ¹⁰ Ω · cm, average primary particle size: 0.5 μm)

(Photoconductor Production Example 17)
A photoconductor was prepared in the same manner as in Photoconductor Preparation Example 15, except that the alumina fine particles in the protective layer coating liquid in Photoconductor Preparation Example 15 were changed to the following.
Tin oxide-antimony oxide powder 4 parts (resistivity: 10 ⁶ Ω · cm, average primary particle size 0.4 μm)

(Photoconductor production example 18)
The aluminum cylinder (JIS 1050) in Photoreceptor Production Example 1 was subjected to the following anodic oxide film treatment, and then a charge generation layer and a charge transport layer were provided in the same manner as in Photoreceptor Production Example 1 without providing an undercoat layer. Was prepared.
◎ Anodic oxide film treatment The support surface is mirror-polished, degreased and washed with water, then immersed in an electrolytic bath of 20 ° C. and 15 vol% sulfuric acid at an electrolytic voltage of 15 V for 30 minutes. Was performed. Further, after water washing, sealing treatment was performed with a 7% nickel acetate aqueous solution (50 ° C.). Thereafter, the substrate was washed with pure water to obtain a support having a 7 μm anodic oxide film formed thereon.

(Photoconductor Production Example 19)
A photoconductor was produced in the same manner as in Photoconductor Production Example 1, except that the titanyl phthalocyanine crystal in Photoconductor Production Example 1 was changed from Pigment 1 produced in Synthesis Example 1 to Pigment 14 produced in Synthesis Example 4. The average particle diameter of the charge generation layer coating liquid using the pigment 14 was 0.20 μm.
15 and 16 show electron micrographs of the dispersion of Pigment 1 and the dispersion of Pigment 14. As is clear from the figure, the particle size of the pigment 14 is smaller than the particle size of the pigment 1, and the particle size is uniform.

(Photoconductor Production Example 20)
A photoconductor was prepared in the same manner as in Photoconductor Preparation Example 1, except that the coating liquid for the charge generation layer in Photoconductor Preparation Example 1 was changed to the following.
A charge generation layer coating solution A dispersion having the following composition was prepared by bead milling under the following conditions.
15 parts of titanyl phthalocyanine pigment (pigment 1) produced in Synthesis Example 1 10 parts of polyvinyl butyral (BX-1 manufactured by Sekisui Chemical Co., Ltd.) 10 parts of 2-butanone 280 parts All butanol and 2-butanone in which butyral was dissolved were charged, and the rotor was rotated at 1500 rpm. p. m. For 30 minutes to prepare a dispersion. The dispersion was taken out from the bead mill and filtered using a cotton wind cartridge filter (TCW-3-CS, effective pore size: 3 μm) manufactured by Advantech. At the time of filtration, a filtration was performed under pressure using a pump.
The titanyl phthalocyanine crystal particle size in the prepared dispersion was measured with a Horiba, Ltd .: CAPA-700. As a result, the average particle size was 0.21 μm.
Further, the coating solution for the charge generation layer used in Preparation Example 20 of the photoconductor and the coating solution for the charge generation layer used in Preparation Example 1 for the photoconductor were thinly coated on a slide glass and coated with an optical microscope (50 times). The state of the film was observed (electron micrographs are shown in FIGS. 17 and 18, respectively). As a result, slight coarse particles were present in the coating liquid for the charge generation layer used in Photoreceptor Preparation Example 1 (dark particles in FIG. 18), but the charge generation layer used in Photoreceptor Preparation Example 20 was used. No coarse particles were found in the coating liquid.

(Examples 7 to 16 and Comparative Examples 34 to 35)
The electrophotographic photoreceptors of the photoreceptor production examples 1 to 5 and 14 to 20 produced as described above are mounted on the electrophotographic apparatus shown in FIG. 1 (150 msec between exposure and development), and the image exposure light source is a 780 nm semiconductor. As a laser (image writing with a polygon mirror), writing is performed at a resolution of 600 dpi, and as a charging member, a 50 μm thick insulating tape is wound around both ends of a charging roller as shown in FIG. Using a charging member (the gap between the photoreceptor and the charging member surface is 50 μm), 100,000 sheets are continuously printed using a chart with a writing rate of 6% under the following charging and exposure conditions. The image after 10,000 copies was evaluated (running environment is 22 ° C.-55% RH). Initially and after 100,000 copies, a solid white image was output to evaluate background contamination (the following rank). After 100,000 sheets, a halftone image was output and image evaluation was performed. Further, the amount of abrasion on the surface of the photoreceptor at the output of 100,000 sheets (the amount of abrasion of the protective layer when a protective layer is provided) was measured.
Table 4 shows the above results.
Charging conditions:
DC bias: -900V
AC bias: 2.0 kV (peak to peak)
Frequency: 1.5kHz
Image exposure conditions:
The exposure energy on the photoreceptor surface is 4.5 erg. / Cm ² of light.

地汚れランク：
　　５：地汚れほとんどなし、
　　４：わずかにあり、
　　３：実使用限界レベル、
　　２以下：実使用には耐えないレベル
　実施例７及び実施例１５、１６のハーフトーン画像を拡大して観察すると、実施例７の画像に比べ、実施例１５、１６のドットは輪郭がはっきりしていた。

Ground dirt rank:
5: Almost no dirt,
4: Slightly
3: Actual use limit level,
2 or less: a level that does not withstand actual use When the halftone images of Example 7 and Examples 15 and 16 are enlarged and observed, the dots of Examples 15 and 16 have sharper contours than the image of Example 7. I was

(Examples 17 to 18 and Comparative Examples 33 to 38)
Using the photoconductors of Photoconductor Production Examples 1 and 20, the optical system of the apparatus used in Example 1 was changed, and writing was performed at 1200 dpi and 400 dpi (exposure amount was 4.5 erg./cm ² , 6 .0erg. / cm ² two conditions), to perform image evaluation in the same manner as in example 1. Table 5 shows the results.

　４００ｄｐｉで書き込みを行なった場合、６００ｄｐｉで書き込んだ場合（実施例１）に比較して解像度が低い。特に比較例３６に比べて、比較例３９の場合に顕著にその傾向が認められる。一方、１２００ｄｐｉで書き込んだ場合、６００ｄｐｉの場合と比較して良好な画像が得られたが、その効果は実施例１７よりも実施例１８の方が著しい。ライン太りに関しては、６．０ｅｒｇ／ｃｍ^２の露光量の場合にいずれも起こっているが、作製例１の感光体よりも作製例２０の感光体を用いた場合にその変化は小さい。

When writing at 400 dpi, the resolution is lower than when writing at 600 dpi (Example 1). In particular, the tendency is remarkably observed in Comparative Example 39 as compared with Comparative Example 36. On the other hand, when writing was performed at 1200 dpi, a better image was obtained as compared with the case of writing at 600 dpi, but the effect was more remarkable in the eighteenth embodiment than in the seventeenth embodiment. Regarding the line thickening, all the cases occur when the exposure amount is 6.0 erg / cm ² , but the change is smaller when the photoconductor of Preparation Example 20 is used than the photoconductor of Preparation Example 1.

(Example 19)
After a running test of 100,000 sheets in Example 9, a one-dot image was output under a 30 ° C.-90% RH environment, and the image was evaluated.

(Example 20)
The charging member in Example 9 was changed from a charging member for proximity arrangement to a scorotron charger, and the surface potential of the non-image portion of the photosensitive member was set to be the same as in Example 9 (-900 V). A running test of 100,000 sheets was performed in the same manner as in Example 9 without changing other conditions. After the 100,000-sheet running test, a 1-dot image was output under a 30 ° C.-90% RH environment as in Example 19, and the image was evaluated.

(Example 21)
The charging member in Example 9 was changed from a charging member for proximity arrangement to a charging member for contact (no gap), and the charging conditions were set to the same conditions as in Example 9. A running test of 100,000 sheets was performed in the same manner as in Example 2 without changing other conditions. After the 100,000-sheet running test, a 1-dot image was output under a 30 ° C.-90% RH environment as in Example 19, and the image was evaluated.

(Example 22)
Evaluation was performed in the same manner as in Example 21 except that the charging conditions in Example 21 were changed as follows.
Charging conditions:
DC bias: -1580 V (surface potential of non-image area of photoconductor is -900 V)
AC bias: None

(Example 23)
Evaluation was performed in the same manner as in Example 9 except that the charging conditions in Example 9 were changed as follows. After the 100,000-sheet running test, a 1-dot image was output under a 30 ° C.-90% RH environment as in Example 19, and the image was evaluated.
Charging conditions:
DC bias: -1580 V (surface potential of non-image area of photoconductor is -900 V)
AC bias: None

(Example 24)
Evaluation was performed in the same manner as in Example 9 except that the gap of the charging member (proximity charging roller) used in Example 9 was changed to 100 μm. After the 100,000-sheet running test, a 1-dot image was output under a 30 ° C.-90% RH environment as in Example 19, and the image was evaluated.

(Example 25)
Evaluation was performed in the same manner as in Example 9 except that the gap of the charging member (proximity charging roller) used in Example 9 was changed to 150 μm. After the 100,000-sheet running test, a 1-dot image was output under a 30 ° C.-90% RH environment as in Example 19, and the image was evaluated.

(Example 26)
Evaluation was performed in the same manner as in Example 9 except that the gap of the charging member (proximity charging roller) used in Example 9 was changed to 250 μm. After the 100,000-sheet running test, a 1-dot image was output under a 30 ° C.-90% RH environment as in Example 19, and the image was evaluated.
Table 6 shows the evaluation results in Examples 19 to 26 described above.

(Photoconductor Production Example 21)
A photoconductor was prepared in the same manner as in Photoconductor Preparation Example 1, except that the coating composition for the charge transport layer in Photoconductor Preparation Example 1 was changed to the following composition.
◎ Coating liquid for charge transport layer 10 parts (TS2050: manufactured by Teijin Chemicals Ltd .: viscosity average molecular weight is about 50,000)
7 parts of charge transport material of the following structural formula

　　テトラヒドロフラン　　　　　　　　　　　　　　　　　　　　　８０部

80 parts of tetrahydrofuran

(Photoconductor Production Example 22)
A photoconductor was prepared in the same manner as in Photoconductor Preparation Example 10, except that the coating composition for the charge transport layer in Photoconductor Preparation Example 10 was changed to the following composition.
◎ Coating liquid for charge transport layer 10 parts (TS2050: manufactured by Teijin Chemicals Ltd .: viscosity average molecular weight is about 50,000)
7 parts of charge transport material of the following structural formula

　　テトラヒドロフラン　　　　　　　　　　　　　　　　　　　　　８０部

80 parts of tetrahydrofuran

(Photoconductor Production Example 23)
A photoconductor was prepared in the same manner as in Photoconductor Preparation Example 1, except that the coating composition for the charge transport layer in Photoconductor Preparation Example 1 was changed to the following composition.
◎ Coating liquid for charge transport layer 10 parts (TS2050: manufactured by Teijin Chemicals Ltd .: viscosity average molecular weight is about 50,000)
7 parts of charge transport material of the following structural formula

　
　　ジオキソラン　　　　　　　　　　　　　　　　　　　　　　　　８０部

Dioxolan 80 parts

(Photoconductor Production Example 24)
A photoconductor was prepared in the same manner as in Photoconductor Preparation Example 1, except that the coating composition for the charge transport layer in Photoconductor Preparation Example 1 was changed to the following composition.
◎ Coating liquid for charge transport layer 10 parts (TS2050: manufactured by Teijin Chemicals Ltd .: viscosity average molecular weight is about 50,000)
7 parts of charge transport material of the following structural formula

　　テトラヒドロフラン　　　　　　　　　　　　　　　　　　　　　４０部
　　トルエン　　　　　　　　　　　　　　　　　　　　　　　　　　４０部

40 parts of tetrahydrofuran 40 parts of toluene

(Examples 27 to 29 and Comparative Example 42)
The photoreceptors of Photoreceptor Production Examples 21 to 24 produced as described above were mounted on the electrophotographic apparatus shown in FIG. As a 780 nm semiconductor laser (image writing using a polygon mirror), writing is performed at a resolution of 600 dpi, and as a charging member, a non-contact proximity charging type charging roller as shown in FIG. And a solid image was output under the following charging and exposure conditions. At the same time, in order to measure the surface potential (unexposed area and image exposed area) of the photoreceptor at the developing section position, a photosensitive jig is used to set the electrometer at the position where the developing device is mounted. Body surface potential was measured. In the measurement of the exposed portion potential, the surface potential when solid writing was performed with a predetermined light amount was measured. Table 7 shows the results together with Example 1 and Comparative Example 5.
Charging conditions:
DC bias: -900V
AC bias: 2.0 kV (peak to peak)
Frequency: 1.5kHz
Image exposure conditions:
The exposure energy on the photoreceptor surface is 4.5 erg. / Cm ²

(Photoconductor Production Example 25)
A photoconductor having the same composition as that of the photoconductor preparation example 1 was manufactured by changing the aluminum cylinder of the photoconductor preparation example 1 to one having a diameter of 30 mm.

(Example 26 of photoconductor production)
A photoconductor having the same composition as that of Photoconductor Production Example 8 was produced by changing the aluminum cylinder of Photoconductor Production Example 8 to a cylinder having a diameter of 30 mm.

(Photoconductor Production Example 27)
A photoconductor having the same composition as that of Photoconductor Production Example 9 was manufactured by changing the aluminum cylinder of Photoconductor Production Example 9 to a cylinder having a diameter of 30 mm.

(Example 30 and Comparative Examples 43 to 47)
The photoreceptors of Photoreceptor Production Examples 25 to 27 produced as described above were mounted together with a charging member on a single process cartridge for an electrophotographic apparatus. ). The four image forming elements were evaluated for 30,000 full-color images under the following process conditions. For evaluation, a solid white image and a full-color image at the initial stage and after 30,000 copies were evaluated. Further, the surface potentials of the photoconductor image area and the non-image area in the black developing section were evaluated in the same manner as in Example 1.
Table 8 shows the results.
Charging conditions:
DC bias: -800V,
AC bias: 1.5 kV (peak to peak)
Frequency: 2.0kHz
Charging member: the same as that used in Example 1 Writing: Writing: Writing was performed at 780 nm LD (using a polygon mirror) at 1200 dpi.
Light amount: 4.5 erg. As exposure energy on the surface of the photoconductor. / Cm ² , 6.0 erg. / Cm ²

Finally, it is verified whether the lowest angle peak of 7.3 ° of the Bragg angle θ, which is a feature of the titanyl phthalocyanine crystal used in the present invention, is the same as the lowest angle of known materials of 7.5 °.
(Measurement example 1)
The pigment (lowest angle 7.3 °) obtained in Synthesis Example 1 was prepared in the same manner as the pigment described in JP-A-61-239248 (having the maximum diffraction peak at 7.5 °), and 3% by weight. % And mixed in a mortar, and the X-ray diffraction spectrum was measured in the same manner as above. The X-ray diffraction spectrum of Measurement Example 1 is shown in FIG.
(Measurement example 2)
The pigment (lowest angle 7.5 °) obtained in Comparative Synthesis Example 1 was prepared in the same manner as the pigment (having the maximum diffraction peak at 7.5 °) described in JP-A-61-239248. % By weight and mixed in a mortar, and the X-ray diffraction spectrum was measured in the same manner as above. The X-ray diffraction spectrum of Measurement Example 2 is shown in FIG.

In the spectrum of FIG. 13, two independent peaks of 7.3 ° and 7.5 ° exist on the low-angle side, and it can be seen that at least the peaks of 7.3 ° and 7.5 ° are different. . On the other hand, in the spectrum of FIG. 14, the low-angle side peak exists only at 7.5 °, which is clearly different from the spectrum of FIG.
From the above, it can be seen that the lowest angle peak of 7.3 ° in the titanyl phthalocyanine crystal of the present invention is different from the peak of 7.5 ° in the known titanyl phthalocyanine crystal.

FIG. 1 is a schematic diagram for explaining an electrophotographic process and an electrophotographic apparatus of the present invention. FIG. 3 is a schematic view showing a proximity charging mechanism (a gap holding mechanism is formed on a charging member side). FIG. 4 is a schematic view illustrating another example of the electrophotographic process of the present invention. FIG. 2 is a schematic view illustrating an example of the electrophotographic process cartridge of the present invention. FIG. 3 is another schematic diagram for explaining the tandem type full-color electrophotographic apparatus of the present invention. FIG. 4 is a diagram illustrating a relationship between an exposure amount and a surface potential. FIG. 2 is a cross-sectional view illustrating a configuration example of an electrophotographic photosensitive member used in the present invention. FIG. 5 is a cross-sectional view illustrating another configuration example of the electrophotographic photosensitive member used in the present invention. It is a figure which shows the X-ray-diffraction spectrum of the dry powder of a water paste. FIG. 3 is a view showing an X-ray diffraction spectrum of a titanyl phthalocyanine crystal obtained in Synthesis Example 2. FIG. 3 is a view showing an X-ray diffraction spectrum of a titanyl phthalocyanine crystal obtained in Comparative Synthesis Example 1. FIG. 9 is a view showing an X-ray diffraction spectrum of a titanyl phthalocyanine crystal obtained in Comparative Synthesis Example 2. FIG. 3 is a view showing an X-ray diffraction spectrum of a titanyl phthalocyanine crystal obtained in Measurement Example 1. FIG. 9 is a view showing an X-ray diffraction spectrum of a titanyl phthalocyanine crystal obtained in Measurement Example 2. 3 is an electron micrograph of a titanyl phthalocyanine crystal obtained in Synthesis Example 1. The scale bar is 0.2 μm. 9 is an electron micrograph of a titanyl phthalocyanine crystal obtained in Synthesis Example 4. The scale bar is 0.2 μm. 31 is an electron micrograph of a dispersion used in Photoconductor Production Example 20. 4 is an electron micrograph of a dispersion used in Photoconductor Production Example 1.

Explanation of reference numerals

1C, 1M, 1Y, 1K ... Drum-shaped photoreceptor 2C, 2M, 2Y, 2K ... Charging member 3C, 3M, 3Y, 3K ... Laser light 4C, 4M, 4Y, 4K ... Developing member 5C, 5M, 5Y, 5K ... Cleaning members 6C, 6M, 6Y, 6K ... Image forming element 7 ... Transfer paper 8 ... Feed roller 9 ... Registration roller 10 ... Transfer conveyance Belt 11C, 11M, 11Y, 11K Transfer brush 12 Fixing device 21 Photoconductor 22 Charge removing lamp 23 Charging member 25 Image exposure unit 26 Development unit 27 Charger before transfer 28 Registration roller 29 Transfer paper 30 Transfer charger 31 Separation charger 32 Separation claw 33 Charger 34 before cleaning Fur brush 35 ……… Blade 41 Conductive support 45 Charge generation layer 47 Charge transport layer 49 Protective layer 50 Photoconductor 51 Charging roller 52 Gap forming member 53 ... Metal shaft 54 ... Image forming area 55 ... Non-image forming area 61 ... Photoconductor 62a ... Drive roller 62b ... Drive roller 63 ... Charger 64 ... Image exposure source 65 Transfer charger 66 Exposure before cleaning 67 Cleaning brush 68 Static elimination light source 69 Developing unit 71 Photoconductor 73 Charging roller 75 Image exposure section 76 cleaning brush 77 developing roller 78 transfer roller

Claims (17)

An electrophotographic apparatus including at least a charging unit, an exposing unit, a developing unit, a transferring unit, and an electrophotographic photoreceptor, and having a time from the exposing unit to the developing unit of 200 msec or less, and having a resolution of 600 dpi or more. Exposure energy when irradiating the photoreceptor with light from the exposure means is 5 erg / cm ² or less on the photoreceptor surface, and the electrophotographic photoreceptor has at least a charge generation layer and a charge transport layer sequentially laminated on a conductive support. An electrophotographic photoreceptor having a maximum diffraction peak at least 27.2 ° in the charge generation layer as a diffraction peak (± 0.2 °) at a Bragg angle 2θ with respect to CuKα radiation (wavelength 1.542 °). Further, it has major peaks at 9.4 °, 9.6 °, and 24.0 °, and has a peak at 7.3 ° as a diffraction peak on the lowest angle side, and 7.3%. An electrophotographic apparatus comprising a titanyl phthalocyanine crystal having no peak between a peak at ° and a peak at 9.4 ° and further having a peak at 26.3 °. The titanyl phthalocyanine crystal is a titanyl phthalocyanine crystal having a peak intensity of 26.3 ° in a range of 0.1 to 5% with respect to a peak intensity of a maximum diffraction peak of 27.2 °. 2. The electrophotographic apparatus according to 1. The electrophotographic apparatus according to claim 1, wherein the titanyl phthalocyanine crystal has an average primary particle size of less than 0.3 μm. The electrophotographic photoreceptor performs dispersion until the titanyl phthalocyanine crystal particles have a volume average particle size of 0.3 μm or less and a standard deviation of 0.2 μm or less, and then are filtered through a filter having an effective pore size of 3 μm or less. The electrophotographic apparatus according to claim 1, wherein the electrophotographic apparatus is obtained by applying a charge generation layer using a dispersion liquid subjected to the above. The titanyl phthalocyanine crystal has a maximum diffraction peak at least at 7.0 to 7.5 ° as a diffraction peak (± 0.2 °) at a Bragg angle of 2θ with respect to characteristic X-rays of CuKα (wavelength 1.542 °), Amorphous titanyl phthalocyanine or low-crystalline titanyl phthalocyanine having an average size of 0.1 μm or less of primary particles having a half width of the diffraction peak of 1 ° or more is subjected to crystal transformation with an organic solvent in the presence of water, and after the crystal transformation. 4. The electrophotographic apparatus according to claim 3, wherein the titanyl phthalocyanine after the crystal conversion from the organic solvent is separated and filtered before the primary particles have an average size of 0.3 μm or more. 5. The electrophotographic apparatus according to any one of claims 1 to 5, wherein the charge transport layer contains a polycarbonate containing at least a triarylamine structure in a main chain and / or a side chain. The electrophotographic apparatus according to claim 1, further comprising a protective layer on the charge transport layer. The electrophotographic apparatus according to claim 7, characterized in that it contains the protective layer Resistivity 10 over ¹⁰ Omega · cm inorganic pigments or metal oxide. The electrophotographic apparatus according to any one of claims 1 to 8, wherein the charge transport layer of the photoconductor is formed using a non-halogen solvent. 10. The electrophotographic apparatus according to claim 9, wherein at least one selected from a cyclic ether and an aromatic hydrocarbon is used as the non-halogen solvent. The electrophotographic apparatus according to any one of claims 1 to 10, wherein a surface of a conductive support of the electrophotographic photosensitive member is subjected to an anodic oxide film treatment. 12. The electrophotographic apparatus according to claim 1, wherein a plurality of image forming elements including at least a charging unit, an exposing unit, a developing unit, a transferring unit, and an electrophotographic photosensitive member are arranged. 13. The electrophotographic apparatus according to claim 1, wherein a contact charging system is used for a charging unit of the electrophotographic apparatus. 13. The electrophotographic apparatus according to claim 1, wherein a non-contact proximity arrangement method is used for a charging unit of the electrophotographic apparatus. 14. The electrophotographic apparatus according to claim 13, wherein a gap between the charging member used for the charging unit and the photoconductor is 200 μm or less. The electrophotographic apparatus according to any one of claims 13 to 15, wherein an AC superimposed voltage is applied to a charging unit of the electrophotographic apparatus. The front electrophotographic apparatus is characterized in that the apparatus includes an apparatus main body in which a photosensitive member and at least one of a charging unit, an exposing unit, a developing unit, and a cleaning unit are integrated, and a detachable cartridge. The electrophotographic apparatus according to claim 1.

Images