JP4274889B2 - Electrophotographic equipment - Google Patents

Description

  The present invention relates to an electrophotographic apparatus using an electrophotographic photosensitive member that is transferred by application of a specific current or more and is formed by sequentially laminating a charge generation layer containing at least a specific titanyl phthalocyanine crystal and a charge transport layer.

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

In recent years, there has been a demand for downsizing and speeding up of the printers and copiers. As a result, the photosensitive member needs to be small and rotate at high speed. Therefore, after the exposure to the photosensitive member, the time until the toner image is developed is shortened, and the rotational number of the photosensitive member is increased. As a result, problems such as accelerating deterioration of electrical characteristics with repeated use have arisen.
As a means to achieve this, the charge generation material is a highly sensitive material, and the maximum is at least 27.2 ° as a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to CuKα rays (wavelength 1.542 mm). It is known to use a titanyl phthalocyanine crystal having a diffraction peak.

  However, this crystal type has a problem that its stability as a crystal is low, and it is easy to undergo a crystal transition against mechanical stress such as dispersion, and thermal stress. Compared to the above, the sensitivity is very low, and when a part of the crystal undergoes crystal transition, a sufficient photocarrier generation function cannot be exhibited. Further, in the repetitive use of the photoconductor, the application of reverse charging to the photoconductor by the transfer means, particularly based on negative / positive development, accelerates the decrease in chargeability, and in particular, an abnormal image called a background image tends to occur. It also has a point.

  In addition, since the frequency of outputting images has increased significantly, it has become an important issue to improve the image quality of the apparatus. To achieve this, (I) a charging means and an exposure means are used. Forming an electrostatic latent image on the photosensitive member to be a high-density image, (II) forming a toner image faithfully to the electrostatic latent image by subsequent developing means, and (III) finally the photosensitive member. There are three problems of accurately transferring the upper toner image onto the transfer paper.

As means for solving these problems, (I) a method of forming an electrostatic latent image by high-density writing using a small-diameter beam on the exposure means, and (II) a toner particle size being reduced in the developing means. A method for forming a toner image faithful to the electrostatic latent image on the photosensitive member, and (III) increasing the gap electric field strength in the transfer means to increase the transfer efficiency and faithfully transferring the toner image on the photosensitive member to the transfer paper. The method of transferring to is mentioned.
However, the increase in the void electric field strength by the transfer means is a titanyl phthalocyanine having a maximum diffraction peak at 27.2 ° as a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to the CuKα ray (wavelength 1.542 mm). When a photoconductor using crystals is repeatedly used, deterioration of electrical characteristics is particularly promoted, which causes an abnormal image called background smearing as described above. For this reason, the high sensitivity of the titanyl phthalocyanine crystal cannot be fully utilized.

  On the other hand, the charge transport layer responsible for the charge transport function mainly comprises the charge transport material 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. As the solvent, halogen-based solvents such as dichloromethane and chloroform are mainly used because they exhibit excellent properties in solubility and coating properties.

  In recent years, awareness of environmental problems has increased, and development of a photoreceptor using a non-halogen solvent that has a low impact on the human body and the environment has been desired. However, as described in Patent Document 1, when a photoreceptor is prepared using a coating solution for a charge transport layer using a non-halogen solvent, a decrease in light attenuation characteristics in a low electric field, a residual potential There is a problem of rising. In particular, a Bragg angle 2θ with respect to a specific crystal type (CuKα ray (wavelength 1.542Å)) that exhibits exceptionally high sensitivity in a wavelength range (600 to 780 nm) in which a relatively stable oscillation output of an LD or LED can be obtained. In the case of titanyl phthalocyanine having a maximum diffraction peak of at least 27.2 ° as a diffraction peak (± 0.2 °), this phenomenon is prominent and it is possible to take advantage of the inherent properties of this charge generating material. It cannot be done and has become a big issue.

Various studies have also been made on methods using non-halogen solvents. For example, a method using a dioxolane compound as a solvent as an organic solvent not containing halogen (for example, see Patent Document 2) has been proposed. Furthermore, a method of adding a specific antioxidant or ultraviolet absorber to a cyclic ether solvent such as tetrahydrofuran has been proposed (see, for example, Patent Documents 3 and 4). However, even if these methods are used, there is a problem that the effect on the above-mentioned defects is not sufficient, or sensitivity characteristics are deteriorated due to the influence of the additive.
Therefore, even when titanyl phthalocyanine having specific high sensitivity is used as a charge generation material and a non-halogen solvent is used as a coating liquid for a charge transport layer, an electrophotographic photosensitive member that exhibits good light attenuation characteristics, and It has been desired to complete the electrophotographic apparatus and the electrophotographic process cartridge used.

JP-A-5-134437 JP-A-10-326023 (page 3, column 3, line 4 to line 25) JP 2001-356506 A (page 3, column 4, line 13 to line 23) JP-A-4-191745 (second page, upper right column, third to ninth lines)

Therefore, an object of the present invention is to provide an electrophotographic apparatus that outputs a stable and high-resolution image without occurrence of abnormal images when repeatedly used at high speed.
Specifically, an electrophotographic apparatus that outputs a stable and high-resolution image by controlling the transfer current in the transfer unit and using a photoconductor that is resistant to electrical degradation of the photoconductor due to reverse charging is provided. There is to do. Another object of the present invention is to provide an electrophotographic apparatus that maintains the high sensitivity inherent to titanyl phthalocyanine even when a non-halogen solvent is used in the coating solution for the charge transport layer.

  In the high-speed digital electrophotographic apparatus, the inventors have made many studies to output a stable and high-resolution image without occurrence of abnormal images when repeatedly used at high speed. An electrophotographic photosensitive member in which an applied current applied to the body is 65 μA or more and the electrophotographic photosensitive member is formed by sequentially laminating at least a charge generation layer and a charge transport layer on a conductive support, and the charge generation layer As a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to CuKα ray (wavelength 1.542 mm), it has a maximum diffraction peak at least 27.2 °, and further 9.4 °, 9.6 °, It has a main peak at 24.0 °, and has a peak at 7.3 ° as the lowest diffraction peak, and there is a peak between the 7.3 ° peak and the 9.4 ° peak. And 26.3 ° By including titanyl phthalocyanine crystals having a click and can solve the above problems.

  Such a transfer current of 65 μA or more is larger than a general transfer current in electrophotography (FIG. 1: From the Electrophotographic Society of Japan “Continuation and Application of Electrophotographic Technology” on page 51, FIG. 1.37). ), Particularly in a high-speed digital electrophotographic apparatus having a linear speed of 200 mm / sec or more, preferably at a high speed. Although the detailed reason for the effect of the present invention is not clear, as a result of our investigation, the titanyl used in the present invention has a maximum diffraction peak at 27.2 ° as compared with other titanyl phthalocyanine crystals known so far. It is presumed to be derived from the high chemical stability of phthalocyanine crystals.

  By the way, as for the transfer current control itself, constant current control is known. For example, JP-A-7-302002, JP-A-10-186886, JP-A-2000-75572, JP-A-2001-305888. It is described in the gazette. In particular, when performing constant current control, the output current from a power supply means (such as a high-voltage power supply) that supplies a charge to the transfer member and the current flowing through the support that supports the transfer belt, etc. are measured, and the monitored difference A feedback control method for controlling the difference by a change is known. In these publications, similar to the facts described in the above-mentioned documents, current control is performed for the purpose of reducing problems that occur when the current flowing through the photosensitive member is too large, and the upper limit is at most. It is a small one of about 50 μA. This is because, similarly to the above-described problem, electrostatic deterioration of the photoconductor occurs due to the application of a reverse bias during transfer. As described above, an effective means for controlling the process has been developed, but an effective photoconductor utilizing the features has been developed. In the present situation, there are still problems such as the presence of residual toner on the toner and the inability to accurately transfer the toner image faithful to the electrostatic latent image on the photoconductor. is doing.

That is, the problem is, (1) "at least charging means of the present invention, an exposure means, a developing means, an electro-photographic apparatus comprising comprises a transfer means, and an electrophotographic photosensitive member, the electrophotographic from said transfer means transfer current applied to the photoreceptor is not less than 65Myuei, the electrophotographic photosensitive member, Ri Na by laminating at least a charge generation layer and a charge transport layer in this order on a conductive support, the charge generation layer is titanyl phthalocyanine The titanyl phthalocyanine crystal contains at least 7.0 to 7.5 ° as a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to the characteristic X-ray (wavelength 1.542 （) of CuKα. An amorphous titanyl phthalocyanine having a maximum diffraction peak, the half-width of the diffraction peak being 1 ° or more, and the average size of primary particles being 0.1 μm or less, or low crystalline Tanyl phthalocyanine is crystallized with an organic solvent in the presence of water, and before the average size of primary particles after crystal transformation grows larger than 0.30 μm, the titanyl phthalocyanine after crystal transformation is fractionated from the organic solvent, As a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to CuKα ray (wavelength 1.542 mm), it has a maximum diffraction peak at least 27.2 °, and further 9.4 °, It has major peaks at 9.6 ° and 24.0 °, and has a peak at 7.3 ° as the lowest diffraction peak, and the peak at 7.3 ° and 9.4 °. There is no peak between the peaks, and further there is a peak at 26.3 °. The peak intensity of 26.3 ° is 0.1 to 5 with respect to the peak intensity of 27.2 ° of the maximum diffraction peak. % And primary particles Electrophotographic apparatus, wherein the average size is less than 0.3μm crystal ";
(2) "the electrophotographic apparatus, the electrophotographic apparatus according to claim (1), characterized in that it performs controlling the transfer current at a constant current control";
( 3 ) “Current measuring means provided in a feedback mechanism for returning to the power source a bypass current that does not flow from the power source to the photosensitive member during transfer but returns to the power source, whereby the output current from the power source and the current measurement The electrophotographic apparatus according to item ( 1 ), wherein the transfer current flowing through the photosensitive member as a difference from the current measured by the means is controlled.
( 4 ) "The charge transporting layer contains a polycarbonate having at least a triarylamine structure in the main chain and / or side chain in any one of the above items (1) to ( 3 )" Electrophotographic device "
( 5 ) "The electrophotographic apparatus according to any one of (1) to ( 4 ), wherein a protective layer is provided on the charge transport layer";
( 6 ) "The electrophotographic apparatus according to ( 5 ), wherein the protective layer contains an inorganic pigment or metal oxide having a specific resistance of 10 ¹⁰ Ω · cm or more";
( 7 ) "The electrophotographic apparatus according to ( 6 ), wherein the metal oxide is any one of alumina, titanium oxide, and silica having a specific resistance of 10 ¹⁰ Ω · cm or more";
( 8 ) “The electrophotographic apparatus according to any one of ( 7 ), wherein the metal oxide is α-alumina having a specific resistance of 10 ¹⁰ Ω · cm or more”;
( 9 ) "The electrophotographic apparatus according to any one of ( 5 ) to ( 8 ) above, wherein the protective layer contains a polymer charge transport material";
( 10 ) The electron according to any one of ( 1 ) to ( 9 ), wherein the charge transport layer of the photoreceptor is formed using a non-halogen solvent. Photo equipment ";
( 11 ) “The electrophotographic apparatus according to item ( 10 ), wherein the non-halogen solvent is at least one selected from cyclic ethers or aromatic hydrocarbons”;
( 12 ) "The electrophotography according to any one of ( 1 ) to ( 11 ) above, wherein the surface of the electroconductive support of the electrophotographic photosensitive member is anodized. apparatus";
( 13 ) Any one of ( 1 ) to (12) above, wherein a plurality of image forming elements comprising at least charging means, exposure means, developing means, transfer means, and electrophotographic photosensitive member are arranged. The electrophotographic apparatus according to Crab ";
( 14 ) "The electrophotographic apparatus according to any one of (1) to ( 13 ), wherein a contact charging method is used as a charging unit of the electrophotographic apparatus";
( 15 ) "The electrophotographic apparatus according to any one of (1) to ( 13 ) above, wherein a non-contact proximity arrangement method is used as a charging unit of the electrophotographic apparatus";
( 16 ) "The electrophotographic apparatus according to any one of ( 15 ) above, wherein a gap between a charging member used in the charging unit and the photosensitive member is 200 µm or less";
( 17 ) "The electrophotographic apparatus according to any one of ( 14 ) to ( 16 ), wherein an AC superimposed voltage is applied to a charging unit of the electrophotographic apparatus";
( 18 ) “The electrophotographic apparatus is mounted with an apparatus main body in which a photosensitive member and at least one means selected from a charging means, an exposure means, a developing means, and a cleaning means are integrated, and a removable cartridge. The electrophotographic apparatus according to any one of ( 1 ) to ( 17 ), characterized in that:

According to the present invention, there is provided an electrophotographic apparatus that outputs a stable and high-resolution image without occurrence of an abnormal image when repeatedly used at high speeds in any environment.
Specifically, there is provided an electrophotographic apparatus that eliminates electrical deterioration of a photoreceptor due to reverse charging in a transfer unit and outputs a stable and high-resolution image. Further, even when a non-halogen solvent is used for the charge transport layer coating solution, an electrophotographic apparatus that maintains the high sensitivity inherent to titanyl phthalocyanine is provided.

First, the electrophotographic apparatus of the present invention will be described in detail with reference to the drawings.
FIG. 2 is a schematic diagram for explaining the electrophotographic process and the electrophotographic apparatus of the present invention, and the following modifications also belong to the category of the present invention.
In FIG. 2, the photosensitive member (1) is provided with a photosensitive layer including at least a charge generation layer and a charge transport layer on a conductive support. As the 2θ diffraction peak (± 0.2 °), it has a maximum diffraction peak at least 27.2 °, and further has major peaks at 9.4 °, 9.6 °, 24.0 °, and The diffraction peak at the lowest angle has a peak at 7.3 °, and there is no peak between the peak at 7.3 ° and the peak at 9.4 °, and a peak at 26.3 °. It contains a titanyl phthalocyanine crystal having the following. The photosensitive member (1) has a drum shape, but may be a sheet or an endless belt.

For the charging roller (3), known means such as a corotron, a scorotron, a solid state charger (solid state charger) or the like can be used.
Further, among charging methods, at least a charging member (indicated as a charging roller (3) in FIG. 2) used for main charging to the photosensitive member is particularly a contact charging method or a non-contact proximity arrangement method. Is desirable. The charging member of the contact charging system or the non-contact proximity arrangement system has advantages such as high charging efficiency, a small amount of ozone generation, and the miniaturization of the apparatus.
The contact-type charging member here is a type in which the surface of the charging member is in contact with the surface of the photosensitive member, and includes a charging roller, a charging blade, and a charging brush. Of these, charging rollers and charging brushes are used favorably.

  Further, the charging member arranged in the proximity is a type in which the charging member is arranged in a non-contact state so as to have a gap (gap) of 200 μm or less between the surface of the photoreceptor and the charging member surface. If this gap is too large, the charging tends to become unstable, and if it is too small, the surface of the charging member may be contaminated when toner remaining on the photoreceptor exists. . Therefore, the gap is suitably 10 to 200 μm, preferably 10 to 100 μm. From the distance of the air gap, it is distinguished from known charging / wire-type chargers such as corotron and scorotron, contact charging members such as contact-type charging rollers, charging brushes and charging blades.

  Since the charging member arranged in this proximity is installed in a state where the surface of the charging member is not in contact with the surface of the photosensitive member, there is little toner contamination on the charging member surface, there is little wear on the charging member surface, and the physical surface of the charging member surface is small. This has the advantage of less mechanical / chemical deterioration, and can also realize high durability of the charging member itself. If the above-mentioned problems occur due to the use of contact charging members and the durability of the charging members is reduced, the charging ability is reduced or the charging becomes uneven in repeated use in an electrophotographic apparatus. Or In order to avoid this charging failure, in repeated use, measures such as increasing the voltage applied to the charging member in accordance with a decrease in charging ability are taken. In this case, the hazard due to charging applied to the photoconductor increases, resulting in a decrease in durability of the photoconductor and generation of abnormal images. Further, as the voltage applied to the charging member increases, the durability of the charging member itself also decreases. However, the use of non-contact charging members improves the durability and stability of the charging member, the photoconductor, and thus the entire system by stabilizing the charging ability of the charging member as the charging member becomes more durable. I will let you.

  The adjacently arranged charging member used in the present invention may have 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 shaft of the photosensitive member and the rotation shaft 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, a gap forming member is disposed at both ends of the non-image forming portion of the charging member, and only this portion is brought into contact with the surface of the photoreceptor, and the image forming region is disposed in a non-contact manner. Alternatively, a method in which a gap forming member at both ends of the photosensitive member 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 can be a simple method to stabilize the gap. It is a method that can be maintained. In particular, the methods described in JP-A Nos. 2002-148904 and 2002-148905 can be used satisfactorily. An example of the proximity charging mechanism in which the gap forming member is arranged on the charging member side is shown in FIG. By using the above-mentioned method, there are advantages such as high charging efficiency and low ozone generation, miniaturization of the apparatus, no contamination with toner, etc., and no mechanical wear due to contact. Because it is used well.

  Furthermore, as an application method, there is an advantage that uneven charging is less likely to occur by using AC superposition, and it can be used satisfactorily. In particular, in the tandem type full-color image forming apparatus described later, in addition to the problem of uneven density of a halftone image due to uneven charging that occurs in the case of a monochrome image forming apparatus, there is a serious problem of deterioration in color balance (color reproducibility). Connected. The above problem is greatly improved by superimposing the AC component on the DC component, but if the AC component conditions (frequency, peak-to-peak voltage) are too large, the hazard to the photoconductor increases. In some cases, deterioration of the photoconductor may be accelerated. For this reason, superposition of alternating current components should be kept to the minimum necessary.

  The frequency of the AC component varies depending on the linear velocity of the photosensitive member, but 3 kHz or less, preferably 2 kHz or less is appropriate. Regarding the peak-to-peak voltage, when the relationship between the voltage applied to the charging member and the charging potential to the photoconductor is plotted, there is a region where the photoconductor is not charged despite the voltage being applied, and the charging rises from a certain point. Potential is observed. About twice this rising potential is the optimum potential (usually about 1200 to 1500 V) as the peak-to-peak voltage. However, when the charging ability of the photosensitive member is low or the linear velocity is very high, the peak-to-peak voltage twice the rising potential as described above may be insufficient. On the other hand, when the chargeability is good, the potential stability may be sufficiently exhibited even when it is twice or less. Therefore, the peak-to-peak voltage is not more than 3 times, preferably not more than 2 times the rising potential. If the peak-to-peak voltage is rewritten as an absolute value, it is desirably used at 3 kV or less, preferably 2 kV or less, more preferably 1.5 kV or less.

  Further, a light source capable of ensuring high luminance such as a light emitting diode (LED), a semiconductor laser (LD), and electroluminescence (EL) is used for the image exposure unit (5). Among these light sources, light emitting diodes and semiconductor lasers have high irradiation energy and long wavelength light of 600 to 800 nm. Therefore, the specific crystal type phthalocyanine pigment which is a charge generation material used in the present invention has high sensitivity. Used well from showing.

  The developing unit (6) can handle both normal development and reversal development depending on the charging polarity of the toner used. When toner having a polarity opposite to the charged polarity of the photoreceptor is used, normal development is used. When toner having the same polarity is used, the electrostatic latent image is developed by reversal development. Depending on the light source used in the previous image exposure unit, in the case of a digital light source used in recent years, there is generally a reversal development method in which toner development is performed on the writing portion in response to a low image area ratio. This is advantageous in view of the life of the light source. There are two methods, a one-component method in which development is performed using only toner and a two-component method in which a two-component developer composed of toner and carrier is used.

  Further, the toner image formed on the photoconductor is transferred onto the transfer paper to become an image on the transfer paper. At this time, there are two methods. One is a method of directly transferring the toner image developed on the surface of the photosensitive member as shown in FIG. 2 to the other, and the other is that the toner image is once transferred from the photosensitive member to the intermediate transfer member, and this is transferred to the transfer paper. It is the method of transferring to. Either case can be used in the present invention.

  Although FIG. 2 shows a transfer belt (10) as a transfer member, a transfer charger or a transfer roller can also be used. Among them, it is desirable to use a contact type such as a transfer belt or a transfer roller that generates less ozone. Any known transfer member can be used as long as it can satisfy the configuration of the present invention.

  As a voltage / current application method at the time of transfer, either a constant voltage method or a constant current method can be used, but the transfer charge amount can be kept constant, and a constant voltage with excellent stability can be used. The current method is more desirable. In particular, by subtracting the current that flows from the power supply member (high-voltage power supply) that supplies electric charge to the transfer member and does not flow into the photosensitive member, the current to the photosensitive member is subtracted. A method of controlling the value is preferred. Specifically, in order to obtain the current flowing through the roller holding the transfer belt, the related member such as the roller is not directly dropped to the ground, but the current flowing through the related member is returned to the high voltage power source. It is desirable to obtain a difference from the output of the power supply and perform constant current control using a high voltage power supply having a feedback function so that the difference becomes a constant value. An example of a circuit configuration diagram that can take such a form is shown in FIG.

  4 includes a transfer conveyance belt (101), a driving roller (102) and a driven roller (103) on which the transfer conveyance belt (101) is stretched, and a transfer conveyance belt (101). It has a bias roller (104) that is in contact with the back surface and a cleaning device (not shown), and the drive roller (102) is connected to the main motor via a gear so that the transfer conveyance belt ( 101) is rotated, and the transfer conveyance belt (101) is brought into contact with the photosensitive drum (100) by the belt contact / separation mechanism. Further, the transfer conveyance belt (101) is separated from the photosensitive drum (100) by the belt contact / separation mechanism when the main motor is turned off.

  The bias roller (104) has a transfer bias having a polarity opposite to the charging polarity of the toner from the high voltage power source (105) to the bias roller (104) when the transfer paper is sent from the registration roller to the transfer means in this example. The transfer paper is applied to the nip portion (transfer nip portion) between the transfer conveyance belt (101) and the photosensitive drum (100) from the high voltage power source (105) via the bias roller (104) and the transfer conveyance belt (101). The toner image on the photosensitive drum (100) is transferred by supplying a charge having a polarity opposite to the charging polarity of the toner.

  The transfer conveying belt (101) is applied with a transfer bias from a high-voltage power source (105) via a bias roller (104) to electrostatically attract the transfer sheet and convey it with rotation. After the toner image is transferred, it is electrostatically separated from the photosensitive drum (100). The transfer paper that has not been separated from the photosensitive drum (100) is separated from the photosensitive drum (100) by a separation claw (not shown) and conveyed by the transfer conveyance belt (101).

In this example, the resistance range of the transfer / conveyance belt (101) is 1 × 10 ⁶ to 1 × 10 ¹² Ω / □, and the resistance range of the transfer / conveyance belt (101), environmental variations, and the thickness of the transfer paper are always maintained. A constant good toner image transfer can be performed. The bias roller (104) is in contact with the transfer conveyance belt (101) on the downstream side in the rotation direction of the transfer conveyance belt (101) from the transfer nip portion, and rotates around the transfer conveyance belt (101) when the main motor rotates. To do.

  In this example, the feedback electrode is not a metal plate or the like, but the drive roller (102) and the driven roller (103) serve as the drive roller (102) and the driven roller (103) are conductive metal rollers. The sliding resistance to the belt (101) can be reduced as much as possible, and the driving roller (102) and the driven roller (103) can reliably function as a feedback electrode. In addition, since the driving roller (102) and the driven roller (103) also serve as feedback electrodes, the apparatus can be simplified and the cost can be reduced. The driving roller (102) and the driven roller (103) are connected to a low voltage side (ground side) terminal of the high voltage power source (105). The low voltage side terminal of the high voltage power source (105) is grounded via the current detection resistor (106), and the photosensitive drum (100) is grounded via the machine body. The current detection resistor (106) is used as a current detection means for detecting a transfer current contributing to the transfer of the toner image.

FIG. 4B shows an equivalent circuit of this transfer portion. In _{FIG, R 11} is the resistance value between the bias roller (104) and the transfer nip of the transfer conveyor belt _{(101), R 12} is the transfer nip and the driven roller in the transfer conveyor belt (101) (103) R ₂ is a resistance value between the bias roller (104) and the drive roller (102) in the transfer conveyance belt (101), _RD is a resistance value of the photosensitive drum (100), and _RP is a transfer value resistance of the paper, the resistance value _{R 1} between the _{R W} represents a resistance value of the current detection resistor (106), a bias roller (104) and a driven roller (103) in the transfer conveying belt (101) _R 1 = R ₁₁ + R ₁₂

In addition, i ₁ is a current flowing from the high-voltage power source (105) through the bias roller (104), the transfer conveyance belt (101), and the driving roller (102), i ₂ is a high-voltage power source (105) from the bias roller (104), transfer conveyor belt (101), the current flowing through the driven roller (103), _{i 3} bias rollers (104) from the high-voltage power supply (105), the transfer conveyor belt (101), transfer sheet, a photoreceptor drum (100) Current flowing through.

  In the configuration of this example, the high-voltage power source (105) is turned on at the timing when the transfer paper sent from the registration roller is conveyed by the transfer conveyance belt (101), and applies the transfer bias to the bias roller (104). At this time, the transfer bias current output from the high voltage power source (105) to the bias roller (104) flows through the transfer conveyance belt (101), the transfer paper, and the photosensitive drum (100), and a part of the transfer bias current is transferred and conveyed. It flows through the belt (101), the driving roller (102), and the driven roller (103).

Although current i ₃ flowing to the photosensitive drum (100) side from the bias roller (104) via a transfer conveyor belt (101) flows a contributing transfer current to the transfer of the toner image to the ground through the machine body, this The current i ₃ returns to the high voltage power source (105) through the current detection resistor (106). The feedback currents i ₁ and i ₂ flowing from the bias roller (104) via the transfer conveyance belt (101) via the driving roller (102) and the driven roller (103) do not pass through the current detection resistor (106). high-voltage power supply returns to (105), a current detecting resistor (106) current-sense resistor (106) reveals the transfer current flowing from the resistance _{R W} of the potential difference and the current detection resistor (106) at both ends of the.

  In this embodiment, the high-voltage power source (105) is a transfer bias power source that outputs a transfer bias current to the bias roller (104), and a transfer current (from the bias roller (104) that flows from the transfer bias power source to the current detection resistor (106). It comprises a constant current control unit that controls the difference between the flowing current and the feedback current flowing into the feedback electrodes (102) and (103) to be a constant set transfer current. The constant current control unit controls the output current of the transfer bias power supply by a PWM pulse, and determines the duty ratio of the PWM pulse (or the gain of the output current of the transfer bias power supply) according to the voltage of the current detection resistor (106). The transfer bias current is controlled to a constant value by updating at a frequency of. For this reason, in the transfer nip portion, the transfer electric field generated by the toner layer surface potential on the photosensitive drum (100) and the surface potential on the transfer paper can be made constant, and the resistance fluctuation of the transfer conveyance belt (101) A good toner image can always be transferred regardless of environmental fluctuations and the thickness of the transfer paper, and a good copy image can be obtained.

  In this example, the constant current control unit of the high-voltage power supply (105) controls the output current of the transfer bias power supply by the PWM pulse, and the duty ratio of the PWM pulse (or the gain of the output current of the transfer bias power supply) is the current. The frequency is updated at a predetermined frequency in accordance with the voltage of the detection resistor (106). This update frequency (cycle) is equal to or lower than the lower limit of the permissible level in human visual characteristics. 5 cycles / mm or more, or every 1 dot line or less of image writing by laser light in the writing unit (less than the time for image writing of 1 dot line). For this reason, it is possible to prevent the occurrence of banding appearing on the copy image in the transfer current update cycle.

Further, as shown in the figure, the current that actually contributes to the transfer of the toner image is the transfer current i ₃ , and i ₁ and i ₂ are the feedback currents that do not contribute to the transfer of the toner image. In this example, since the transfer current i ₃ is controlled to be constant by the constant current control unit of the high voltage power source (105), the transfer bias voltage applied from the high voltage power source (105) to the bias roller (104) is the transfer current i _3. Is determined by the resistance (R ₁₁ , R _D , R _P , R _W ) and the transfer current i ₃ . For this reason, if R ₁₁ is larger than R ₂ , i ₁ that does not contribute to toner image transfer increases, and the capacity of the transfer bias power source must be increased, which is not a very efficient system. . Therefore, in this embodiment, _{L 1} the distance from the bias roller (104) to the driven roller (103), and the distance from the bias roller (104) to the drive roller (102) and _{L 2, R 1} and _{R 2} Are designed such that L ₁ <L ₂ so that R ₁ <R ₂ . For this reason, the capacity of the transfer bias power supply can be kept small.

The transfer current is a current based on the amount of charge required to peel off the toner that is electrostatically attached to the photosensitive member and transfer it to the transfer target (transfer paper or intermediate transfer member). In order to avoid transfer defects such as transfer residue, it is only necessary to increase the transfer current. However, when negative / positive development is used, charging with a polarity opposite to the charging polarity of the photoconductor is applied. As a result, the electrostatic fatigue of the photoconductor becomes remarkable. For this reason, in the electrophotographic apparatus so far, the deterioration of the electrostatic fatigue characteristics due to the reverse charging applied to the photoconductor is rate-limiting, and it is difficult to increase the transfer current. It has been found that this problem can be solved by using a photoreceptor using a titanyl phthalocyanine crystal having the following.
The larger the transfer current, the more advantageous it is because a charge amount exceeding the electrostatic adhesion force between the photoconductor and the toner can be given. As a result, the developed toner image is scattered. For this reason, the upper limit is a range in which this discharge phenomenon does not occur. This threshold value varies depending on the gap (distance) between the transfer member and the photoconductor, the material constituting the both, and the like, but the discharge phenomenon can be avoided by using it at about 200 μA or less. Therefore, the upper limit value of the transfer current is about 200 μA.

Use light sources such as fluorescent lamps, tungsten lamps, halogen lamps, mercury lamps, sodium lamps, light-emitting diodes (LEDs), semiconductor lasers (LDs), and electroluminescence (ELs) as light sources such as static elimination lamps (2). Can do. Various types of 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 to irradiate only light in a desired wavelength range.
Such a light source or the like irradiates the photosensitive member with light by providing a transfer process, a static elimination process, a cleaning process, or a pre-exposure process using light irradiation in addition to the process shown in FIG.
This neutralization mechanism can be omitted when the AC component is superposed and used in the previous charging method, or when the residual potential of the photoreceptor is small. Further, instead of optical static elimination, an electrostatic static elimination mechanism (for example, a static elimination brush with a reverse bias applied or grounded) can be used.
Further, the toner developed on the photosensitive member (1) by the developing unit (6) is transferred to the transfer paper (7). If toner remaining on the photosensitive member (1) is generated, a fur brush ( 14) and the blade (15) to remove from the photoreceptor. 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.

  The image forming means as described above may be fixedly incorporated in a copying apparatus, a facsimile, or a printer, but may be incorporated in these apparatuses in the form of a process cartridge. A process cartridge is a single device (part) that contains a photoconductor and further includes a charging unit, an exposure unit, a developing unit, a transfer unit, a cleaning unit, a neutralizing unit, and the like. There are many shapes and the like of the process cartridge, but a general example is shown in FIG. The photoreceptor (1) is provided with a photosensitive layer including at least a charge generation layer and a charge transport layer on a conductive support, and the charge generation layer has a diffraction peak with a Bragg angle 2θ with respect to CuKα rays (wavelength 1.542 mm). (± 0.2 °) having a maximum diffraction peak at least 27.2 °, and further having major peaks at 9.4 °, 9.6 °, and 24.0 °, and the lowest angle side As a diffraction peak, a titanyl phthalocyanine crystal having a peak at 7.3 °, no peak between the peak at 7.3 ° and the peak at 9.4 °, and a peak at 26.3 ° is obtained. It contains. When this process cartridge is used in an image forming apparatus, the transfer current applied from the transfer means to the photosensitive member is used at 65 μA or more.

Here, the transfer current is defined. The transfer current can be defined as a current flowing from the charging member to the photosensitive member. Further, when a toner image is directly transferred onto a transfer material (paper or the like), it can be defined as a current that flows through the photoconductor when the transfer material is up to the full width of the transfer member. In the case of a system in which primary transfer is performed using an intermediate transfer member and then secondary transfer is performed on a transfer material, the current is defined as a current flowing from the intermediate transfer member to the photosensitive member.
There are several methods for this measurement method, but two methods will be described as examples.
One is to measure the current that actually flows through the photoconductor, and to measure the current that flows from the photoconductor toward the ground. However, during operation of the electrophotographic apparatus, current from charging is also included. Therefore, when directly measuring the current from the photoconductor to the ground, it is necessary to perform the operation only with the transfer member. There is.
The other is an indirect measurement method. The current output from the high-voltage power supply used in the transfer unit is measured, the current flowing to the transfer member other than the photoconductor (for example, the drive roller of the transfer belt) is measured, and the difference between the two is obtained to the photoconductor. The transfer current is obtained indirectly. In this measurement method, a high-voltage power supply having a feedback function is used, and the roller or the like is not grounded but returned to the high-voltage power supply so that the difference between the output current and the return current can be detected. It is convenient to use one.

FIG. 6 is a schematic diagram for explaining the tandem-type full-color electrophotographic apparatus of the present invention, and the following modifications also belong to the category of the present invention.
In FIG. 6, reference numerals (1C), (1M), (1Y), and (1K) denote drum-shaped photoconductors, and the photoconductor (1) has at least a charge generation layer and a charge transport layer on a conductive support. The charge generation layer has a maximum diffraction peak at 27.2 ° as a Bragg angle 2θ diffraction peak (± 0.2 °) with respect to CuKα rays (wavelength 1.542 mm). Further, it has major peaks at 9.4 °, 9.6 ° and 24.0 °, and has a peak at 7.3 ° as the lowest diffraction peak, and the peak at 7.3 °. And a titanyl phthalocyanine crystal having no peak between the peak at 9.4 ° and a peak at 26.3 °. The photoreceptors (1C), (1M), (1Y), (1K) rotate in the direction of the arrow in the figure, and charging members (2C), (2M), (2Y), (2K) at least in the order of rotation therearound. ), Developing members (4C), (4M), (4Y), (4K), and cleaning members (5C), (5M), (5Y), (5K). The charging members (2C), (2M), (2Y), and (2K) are charging members that constitute a charging device for uniformly charging the surface of the photoreceptor. From an exposure member (not shown) from the back side of the photoreceptor between the charging members (2C), (2M), (2Y), (2K) and the developing members (4C), (4M), (4Y), (4K). Laser beams (3C), (3M), (3Y), and (3K) are irradiated so that an electrostatic latent image is formed on the photoreceptors (1C), (1M), (1Y), and (1K). It has become. Then, the four image forming elements (6C), (6M), (6Y), and (6K) centering on such photoconductors (1C), (1M), (1Y), and (1K) are transferred materials. They are juxtaposed along a transfer conveyance belt (10) that is a conveyance means. The transfer conveyance belt (10) includes developing members (4C), (4M), (4Y), (4K) and cleaning members (5C) of the image forming units (6C), (6M), (6Y), (6K). , (5M), (5Y), (5K) are in contact with the photoconductors (1C), (1M), (1Y), (1K) and hit the back side of the photoconductor side of the transfer conveyance belt (10). 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 the others are the same in configuration.

  In the color electrophotographic apparatus having the configuration shown in FIG. 6, the image forming operation is performed as follows. First, in each of the image forming elements (6C), (6M), (6Y), (6K), the photoconductors (1C), (1M), (1Y), (1K) are in the direction indicated by the arrow (the direction along with the photoconductor). ) Are rotated by charging members (2C), (2M), (2Y), (2K) that are rotated, and laser light (3C), (3M) is then exposed by an exposure unit (not shown) disposed inside the photoreceptor. ), (3Y), and (3K) form an electrostatic latent image corresponding to each color image to be created. Next, the latent image is developed by the developing members (4C), (4M), (4Y), and (4K) to form a toner image. Development members (4C), (4M), (4Y), and (4K) are development members that perform development with toners of C (cyan), M (magenta), Y (yellow), and K (black), respectively. The toner images of the respective colors formed on the two photoconductors (1C), (1M), (1Y), and (1K) are superimposed on the transfer paper. The transfer paper (7) is fed out from the tray by the paper feed roller (8), temporarily stopped by the pair of registration rollers (9), and then transferred to the transfer conveyance belt (10) in synchronization with the image formation on the photosensitive member. Sent. The transfer paper (7) held on the transfer conveyance belt (10) is conveyed, and each color is in contact position (transfer section) with each photoconductor (1C), (1M), (1Y), (1K). The toner image is transferred. The toner image on the photoconductor is transferred to the transfer brush (11C), (11M), (11Y), (11K) and the photoconductor (1C), (1M), (1Y), (1K). The image is transferred onto the transfer paper (7) by an electric field formed from the potential difference. Then, the recording paper (7) on which the toner images of four colors are superimposed through the four transfer portions is conveyed to the fixing device (12), where the toner is fixed, and is discharged to a paper discharge portion (not shown). Further, residual toner remaining on the photosensitive members (1C), (1M), (1Y), and (1K) without being transferred by the transfer unit is removed from the cleaning devices (5C), (5M), (5Y), ( 5K). In the example of FIG. 6, 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 conveyance direction. However, it is not limited to this order, and the color order is arbitrarily set. Further, when creating a black-only document, providing a mechanism that stops image forming elements other than black ((6C), (6M), (6Y)) can be used particularly effectively in the present invention. . Further, although the charging member is in contact with the photosensitive member in FIG. 6, by using a charging mechanism as shown in FIG. 3, an appropriate gap (about 10 to 200 μm) is provided between them. In addition, the wear amount of the both can be reduced, and toner filming on the charging member can be reduced and the toner can be used well.

  The image forming means as described above may be fixedly incorporated in a copying apparatus, facsimile, or printer, but each electrophotographic element may be incorporated in the apparatus in the form of a process cartridge. A process cartridge is a single device (part) that contains a photoconductor and further includes a charging unit, an exposure unit, a developing unit, a transfer unit, a cleaning unit, a neutralizing unit, and the like.

Hereinafter, the electrophotographic photosensitive member used in the present invention will be described in detail.
The electrophotographic photosensitive member of the present invention is an electrophotographic photosensitive member in which at least a charge generation layer and a charge transport layer are formed on a conductive support, and CuKα rays (wavelength 1.542Å) are formed in the charge generation layer. As a diffraction peak (± 0.2 °) with a Bragg angle of 2θ, the maximum diffraction peak is at least 27.2 °, and the main peaks are at 9.4 °, 9.6 °, and 24.0 °. In addition, the diffraction peak at the lowest angle side has a peak at 7.3 °, and there is no peak between the 7.3 ° peak and the 9.4 ° peak, and further 26.3 °. Containing a titanyl phthalocyanine crystal having a peak.
This crystal type is described in JP-A No. 2001-187794. By using this titanyl phthalocyanine crystal, it is stable without causing a decrease in chargeability even after repeated use without losing high sensitivity. An electrophotographic photoreceptor can be obtained.
Japanese Patent Laid-Open No. 2001-187794 discloses a charge generating material used in the present invention, a photoreceptor using the same, an electrophotographic apparatus, and the like. However, under the situation where it is used at a resolution of 600 dpi or higher or 1200 dpi or higher, unless the transfer current is optimized (larger than usual), the resolution is lowered due to the transfer failure as described above. It was. Such a phenomenon appears remarkably when used in an image forming apparatus that is faster than the image forming apparatus described in the publication. Thus, in the past process (apparatus), not only the ability of the material described in the same publication is not sufficiently drawn out, but if the process conditions are not optimized, a side effect is produced.

  Further, as a method for synthesizing titanyl phthalocyanine crystals, a method using no titanium halide as a raw material can be favorably used as described in JP-A-6-293769. The biggest merit of this method is that the synthesized titanyl phthalocyanine crystal is free of halogenation. When a titanyl phthalocyanine crystal contains a halogenated titanyl phthalocyanine crystal as an impurity, it often has adverse effects such as a decrease in photosensitivity and a decrease in chargeability in the electrostatic characteristics of a photoconductor using the crystal (Japan Hardcopy '89 paper). P. 103 1989). Also in the present invention, the halogenated free titanyl phthalocyanine crystal as described in JP-A-2001-187794 is mainly used, 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 “Phthalogyneines Compounds” (1963), “The Phthalogianines” (1983), and Japanese Patent Application Laid-Open No. Hei 6-293769 by Moser et al.

  For example, as a first method, a mixture of phthalic anhydrides, metal or metal halide 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 in combination as necessary.

  As a second method, phthalonitriles and metal halides 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, such as aluminum phthalocyanines, indium phthalocyanines, oxovanadium phthalocyanines, oxotitanium phthalocyanines, zirconium phthalocyanines, and the like. The third method is to first react phthalic anhydride or phthalonitrile with ammonia to produce an intermediate such as 1,3-diiminoisoindoline, and then react with a metal halide in a high boiling solvent. It is a method to make it. The fourth method is a method in which phthalonitriles and a metal alkoxide are reacted in the presence of urea or the like. In particular, the fourth method does not cause chlorination (halogenation) to the benzene ring, and is a very useful method as a method for synthesizing an electrophotographic material.

  Next, a method for synthesizing amorphous titanyl phthalocyanine (low crystalline titanyl phthalocyanine) will be described. In this method, phthalocyanines are dissolved in sulfuric acid, diluted with water and reprecipitated, and an acid paste method or an acid slurry method can be used.

  As a specific method, the above synthetic crude product is dissolved in 10-50 times the amount of concentrated sulfuric acid, and if necessary, insoluble matter is removed by filtration or the like, and this is sufficiently cooled to 10-50 times the amount of sulfuric acid. Slowly throw it into water or ice water to reprecipitate titanyl phthalocyanine. The precipitated titanyl phthalocyanine is filtered, washed with ion-exchanged water and filtered, 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 content concentration of about 5 to 15 wt%. What was produced in this way was the amorphous titanyl phthalocyanine (low crystalline titanyl phthalocyanine) used in the present invention. In this case, the amorphous titanyl phthalocyanine (low crystalline titanyl phthalocyanine) is at least 7.0 to 7 as a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to the characteristic X-ray (wavelength 1.542Å) of CuKα. It is preferable to have a maximum diffraction peak at 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 from at least two crystal conversion steps.
First, the first crystal conversion method will be described. In the first crystal conversion, the amorphous titanyl phthalocyanine (low crystalline titanyl phthalocyanine) is used as a diffraction peak (± 0.2 °) at a Bragg angle 2θ with respect to the characteristic X-ray of CuKα (wavelength 1.542 mm). It has a maximum diffraction peak at 2 °, a major peak at 9.4 °, 9.6 ° and 24.0 °, and a peak at 7.3 ° as the lowest diffraction peak. And a titanyl phthalocyanine crystal having no peak between the 7.3 ° peak and the 9.4 ° peak and having no peak at 26.3 °.

As a specific method, the crystalline form is obtained by mixing and stirring together with an organic solvent in the presence of water without drying the amorphous titanyl phthalocyanine (low crystalline titanyl phthalocyanine). .
In this case, any organic solvent can be used as long as the desired crystal form can be obtained, but tetrahydrofuran, toluene, methylene chloride, carbon disulfide, orthodichlorobenzene, 1,1, Good results are obtained when one selected from 2-trichloroethane is selected. These organic solvents are preferably used alone, but two or more of these organic solvents may be mixed or used in combination with other solvents.
It is desirable that the amount of the organic solvent used for crystal conversion is 10 times or more, preferably 30 times or more the weight of amorphous titanyl phthalocyanine. This is because the crystal conversion is caused quickly and sufficiently, and the effect of sufficiently removing impurities contained in the amorphous titanyl phthalocyanine is exhibited. The amorphous titanyl phthalocyanine used here is prepared by the acid paste method, but it is desirable to use one obtained by sufficiently washing sulfuric acid as described above. When crystal conversion is performed under conditions where sulfuric acid remains, sulfate ions remain in the crystal particles, and the completed crystals cannot be completely removed even by an operation such as washing with water. When sulfate ions remain, preferable results cannot be obtained, such as a decrease in sensitivity and a decrease in chargeability of the photoreceptor. For example, JP-A-8-110649 (comparative example) describes a method for carrying out crystal conversion by adding titanyl phthalocyanine dissolved in sulfuric acid into an organic solvent together with ion-exchanged water. 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. The method for producing titanyl phthalocyanine of the present invention is not good.

  The above crystal conversion method is a crystal conversion method according to the above-mentioned Japanese Patent Application Laid-Open No. 2001-187794. In the charge generating material contained in the photoreceptor used in the electrophotographic apparatus of the present invention, the effect becomes even more remarkable by making the particle size of the titanyl phthalocyanine crystal finer.

  In order to make the particle size of the titanyl phthalocyanine crystal finer, the present inventors have observed that the above-mentioned amorphous titanyl phthalocyanine (low crystalline titanyl phthalocyanine) has a primary particle size of 0.1 μm or less (its Although most of them are about 0.01 to 0.05 μm (FIG. 15), it has been found that the crystals are converted with crystal growth during the crystal conversion. Usually, in this type of crystal conversion, a sufficient crystal conversion time is ensured due to fear of remaining of the raw material, and after the crystal conversion is sufficiently performed, filtration is performed to obtain a titanyl phthalocyanine crystal having a desired crystal type. Is what you get. For this reason, even though a raw material having sufficiently small primary particles is used as a raw material, a crystal having a large primary particle (approximately 0.3 to 0.5 μm) is obtained as a crystal after crystal conversion. There is (FIG. 16).

When dispersing the titanyl phthalocyanine crystal thus prepared, the particle size after dispersion is made small (less than 0.3 μm, preferably 0.25 μm or less, more preferably 0.2 μm or less). The dispersion is performed by giving a strong energy for pulverizing the primary particles as necessary. As a result, as described above, a part of the particles are easily transferred to a crystal type which is not a desired crystal type.
The particle size referred to here is a volume average particle size, and is determined by an ultracentrifugal automatic particle size distribution analyzer: CAPA-700 (manufactured by Horiba, Ltd.). At this time, the particle size (Median system) corresponding to 50% of the cumulative distribution was calculated. However, this method may not be able to detect a very small amount of coarse particles. Therefore, in order to obtain more details, it is important to observe the titanyl phthalocyanine crystal powder or dispersion directly with an electron microscope and determine its size. It is.

As a result of further observation of the dispersion and examination of micro defects, the above phenomenon was understood as follows. Usually, in the method of measuring the average particle size, when an extremely large particle is present in several% or more, the presence can be detected, but it is about 1% or less of the whole. When the amount is too small, the measurement is below the detection limit. As a result, the presence of coarse particles is not detected only by measuring the average particle size, making it difficult to interpret the above minute defects.
FIG. 18 and FIG. 19 show photographs observing the state of two types of dispersions in which only the dispersion time is changed while fixing the dispersion conditions. A photograph of the dispersion liquid having a short dispersion time under the same conditions is shown in FIG. 18, and it is observed that coarse particles remain as compared with FIG. 19 having a long dispersion time. The black particles in FIG. 18 are coarse particles. The average particle size and particle size distribution of these two types of dispersions were measured by a commercially available particle size distribution measuring device (manufactured by Horiba: Ultracentrifugal automatic particle size distribution measuring device, CAPA700). The result is shown in FIG. “A” in FIG. 20 corresponds to the dispersion shown in FIG. 18, and “B” corresponds to the dispersion shown in FIG. When both are compared, there is almost no difference in the particle size distribution. In addition, the average particle diameter values of the two are “A” of 0.29 μm and “B” of 0.28 μm, and taking into account measurement errors, no difference is recognized between the two.
Therefore, it is understood that the remaining of a very small amount of coarse particles cannot be detected only by the definition of the known average particle size (particle size), and it is not possible to cope with the recent high-resolution negative / positive development. The presence of such a minute amount of coarse particles can be recognized for the first time by observing the coating solution at the microscope level.

  In response to such a fact, it is an effective means to produce as small primary particles as possible during the first crystal conversion. For this purpose, in order to complete the crystal conversion in a short time while selecting the appropriate crystal conversion solvent as described above and improving the crystal conversion efficiency, the solvent and titanyl phthalocyanine water paste (the raw material prepared as described above) are used. ) Is effective to use strong agitation in order to sufficiently bring Specifically, it is possible to achieve crystal conversion in a short time by using a propeller with a very strong stirring force or using a strong stirring (dispersing) means such as a homogenizer (homomixer). is there. Under these conditions, it is possible to obtain a titanyl phthalocyanine crystal in a state in which crystal conversion is sufficiently performed and crystal growth does not occur without remaining raw materials.

  In addition, since the crystal grain size and the crystal conversion time are in a proportional relationship as described above, a method of immediately stopping the reaction when a predetermined reaction (crystal conversion) is completed is also an effective means. As the above-mentioned means, it is possible to immediately add a large amount of a solvent in which crystal conversion hardly occurs after crystal conversion as described above. Examples of the solvent that hardly causes crystal transformation include alcohol-based and ester-based solvents. Crystal conversion can be stopped by adding about 10 times these solvents to the crystal conversion solvent. By adopting 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 (FIG. 17). . FIG. 17 shows a TEM image of a titanyl phthalocyanine crystal when crystal conversion is performed in a short time. Unlike the case of FIG. 16, the particle size is small and almost uniform, and no coarse particles as observed in FIG. 16 are observed. In addition to the technique described in JP-A-2001-187794, the use of the technique as described above (a crystal conversion method for obtaining fine titanyl phthalocyanine crystals) in combination with the effect of the present invention as necessary. It is an effective means to increase

Subsequently, the crystallized titanyl phthalocyanine crystal is immediately filtered to be separated from the crystal conversion solvent. This filtration is performed by using a filter of an appropriate size. In this case, it is most appropriate to use vacuum filtration.
Thereafter, the separated titanyl phthalocyanine crystal is heat-dried as necessary. Any known dryer can be used for heating and drying, but a blower-type dryer is preferable when the drying is performed in the atmosphere. Furthermore, drying under reduced pressure is also a very effective means in order to increase the drying speed and to exhibit the effects of the present invention more remarkably. In particular, this is an effective means for a material that decomposes at a high temperature or changes its crystal form. It is particularly 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 conversion is a step of further crystal conversion using the titanyl phthalocyanine crystal (dry powder) prepared by the first crystal conversion. Specific methods include two methods.
One is a method of treating the previously prepared titanyl phthalocyanine crystal in an organic solvent. As the organic solvent used, any solvent can be used as long as it can convert the crystal form having the maximum diffraction peak at 27.2 ° to the crystal form having the 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 together. ,It is valid. After the treatment with an organic solvent, the target titanyl phthalocyanine crystal can be obtained by separating by filtration and drying again.

As another method, a crystal transformation is performed by applying a mechanical shearing force to the previously prepared titanyl phthalocyanine crystal. At this time, an organic solvent may be used in combination, but it is desirable to perform the treatment in a dry state without using it together. As a method to be used, dry milling using a ball mill, attritor, vibration mill, kneader, or the like, or simply dry milling using a mixer is also effective. Moreover, you may use inorganic salts, such as salt, as an adjuvant in the case of dry milling. When an auxiliary agent is used, a washing step for removing inorganic salts is necessary after the crystal conversion treatment. Thus, the target 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% with respect to the peak intensity at the maximum diffraction peak of 27.2 °. The peak intensity of 26.3 ° is determined by the treatment time in the solvent or the treatment time giving mechanical shearing force, but the state of the raw material used (the titanyl phthalocyanine crystal produced by the first crystal conversion) (for example, It is desirable to determine the treatment time through preliminary experiments because it varies depending on the size and hardness of the powder.

  The thus obtained titanyl phthalocyanine crystal having a specific crystal type is extremely useful as a charge generating material for an electrophotographic photoreceptor. However, as described above, the crystal form is unstable, and the crystal form is easily transferred when a dispersion is prepared. However, by synthesizing primary particles into infinitely small particles as in the present invention, a dispersion with a small average particle diameter can be prepared without giving an excessive share during the preparation of the dispersion, and the crystal type is also extremely high. It can be produced stably (without changing the synthesized crystal form).

  A general method is used for the preparation of the dispersion, and the titanyl phthalocyanine crystal is dispersed in a suitable solvent together with a binder resin as necessary by using a ball mill, an attritor, a sand mill, a bead mill, an ultrasonic wave, or the like. It is obtained. At this time, the binder resin may be selected depending on the electrostatic characteristics of the photoreceptor, and the solvent may be selected depending on the wettability to the pigment, the dispersibility of the pigment, and the like.

  As already mentioned, the titanyl phthalocyanine crystal having a maximum diffraction peak at 27.2 ° as a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to CuKα rays (wavelength 1.542 mm) is It is known that a crystal transition easily occurs to another crystal type due to a stress such as a dynamic share. This tendency does not change in the titanyl phthalocyanine crystal used in the present invention. In other words, in order to produce a dispersion containing fine particles, it is necessary to devise a dispersion method, but the stability of the crystal form and the micronization tend to be in a trade-off relationship. Although there are methods for avoiding this by optimizing the dispersion conditions, all of them make the manufacturing conditions extremely narrow, and a simpler method is desired. In order to solve this problem, the following method is also an effective means.

  That is, after preparing a dispersion liquid in which the particles are made as fine as possible without causing crystal transition, it is a method of filtering with a suitable filter. This method is a very effective means in that it can remove a minute amount of coarse particles that cannot be visually observed (or cannot be detected by particle size measurement), and that the particle size distribution is uniform. 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. Also by this method, a dispersion containing only titanyl phthalocyanine crystals 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. By mounting and using the body, the effect of the present invention is further enhanced.

The intensity ratio of the 26.3 ° peak intensity to the 27.2 ° peak intensity in the titanyl phthalocyanine crystal of the present invention will be described.
An X-ray diffraction spectrum is measured with a general X-ray diffractometer in a powder state of the titanyl phthalocyanine crystal to be used. Baseline correction is performed on the obtained spectrum, and then a peak intensity of 26.3 ± 0.2 ° and a peak intensity of 27.2 ± 0.2 ° are obtained. Using the value, the value obtained by dividing the peak intensity of 26.3 ± 0.2 ° by the peak intensity of 27.2 ± 0.2 ° is the peak intensity ratio in the present invention.

なお、ピーク強度比が１％以下になるような場合には、広い範囲での測定ではベースラインの補正が難しい場合がある。その場合には、測定範囲を狭めて（例えば、２５〜３０゜の範囲で測定する等）、再測定を行なうことにより、より正確に強度比を求めることができる。

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

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 photosensitive member used in the present invention. On the conductive support (31), a charge generation layer (35) mainly composed of a charge generation material, and a charge The charge transport layer (37) mainly composed of a transport material has a laminated structure.
FIG. 8 is a cross-sectional view showing another structural example of the electrophotographic photosensitive member used in the present invention. On the conductive support (31), the intermediate layer (33) and the charge generation material are the main components. The charge generation layer (35) to be formed and the charge transport layer (37) mainly composed of the charge transport material are laminated.

As the conductive support (31), a material having a volume resistance of 10 ¹⁰ Ω · cm or less, for example, a metal such as aluminum, nickel, chromium, nichrome, copper, gold, silver, platinum, tin oxide, oxidation Metal oxide such as indium by vapor deposition or sputtering, film or cylindrical plastic, paper coated, or aluminum, aluminum alloy, nickel, stainless steel plates, etc. and methods such as extrusion and drawing After forming the tube, it is possible to use a tube subjected to surface treatment such as cutting, superfinishing or polishing. Further, an endless nickel belt and an endless stainless steel belt disclosed in Japanese Patent Application Laid-Open No. 52-36016 can be used as the conductive support (31).
Of these, a cylindrical support made of aluminum, which can be easily subjected to the anodic oxide film treatment, can be most preferably used. As used herein, aluminum includes both pure aluminum and aluminum alloys. Specifically, JIS 1000, 3000, and 6000 series aluminum or aluminum alloy is most suitable. Anodized films are obtained by anodizing various metals and various alloys in an electrolyte solution. Among them, a film called anodized aluminum or an aluminum alloy that has been anodized in an electrolyte solution is used in the present invention. Is the most suitable. In particular, it is excellent in preventing point defects (black spots, background stains) that occur when used in reversal development (negative / positive development).

The anodizing treatment is performed in an acidic bath such as chromic acid, sulfuric acid, oxalic acid, phosphoric acid, boric acid, sulfamic acid. Of these, treatment with a sulfuric acid bath is most suitable. For example, sulfuric acid concentration: 10-20%, bath temperature: 5-25 ° C., current density: 1-4 A / dm ² , electrolysis voltage: 5-30 V, treatment time: 5-60 minutes However, the present invention is not limited to this. Since the anodic oxide film produced in this way is porous and has high insulation, the surface is very unstable. For this reason, there is a change with time after fabrication, and the physical property value of the anodized film is likely to change.

  In order to avoid this, it is desirable to further seal the anodized film. Examples of the sealing treatment include a method of immersing the anodized film in an aqueous solution containing nickel fluoride and nickel acetate, a method of immersing the anodized film in boiling water, and a method of treating with pressurized steam. Among these, the method of immersing in the aqueous solution containing nickel acetate is the most preferable.

  Subsequent to the sealing treatment, the anodic oxide film is washed. The main purpose of this is to remove excess metal salts and the like attached by the sealing treatment. If this remains excessively on the surface of the support (anodized film), it not only adversely affects the quality of the coating film formed on this surface, but also generally low resistance components remain, resulting in the occurrence of soiling. It can also be a cause. The cleaning may be performed once with pure water, but is usually performed at another stage. At this time, it is preferable that the final cleaning liquid is as clean (deionized) as possible. Moreover, it is desirable to perform physical rubbing cleaning with a contact member in one of the other cleaning processes. The film thickness of the anodized film formed as described above is desirably about 5-15 μm. If it is too thin, the barrier effect as an anodic oxide film is not sufficient, and if it is too thick, the time constant as an electrode becomes too large, resulting in the generation of residual potential and the response of the photoreceptor. There is a case.

In addition to the above, a conductive powder dispersed in a suitable binder resin and coated on the support can be used as the conductive support (31) 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, or metal oxide powder such as conductive tin oxide and ITO. It is done. The binder resin used at the same time is polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, 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-vinylcarbazole, acrylic resin, silicone resin, epoxy resin, Examples thereof include thermoplastic, thermosetting resins, and photocurable resins such as melamine resin, urethane resin, phenol resin, and alkyd resin. Such a conductive layer can be provided by dispersing and coating these conductive powder and binder resin in a suitable solvent such as tetrahydrofuran, dichloromethane, methyl ethyl ketone, and toluene.
Furthermore, a heat-shrinkable tube in which the conductive powder is contained in a material such as polyvinyl chloride, polypropylene, polyester, polystyrene, polyvinylidene chloride, polyethylene, chlorinated rubber, polytetrafluoroethylene fluororesin on a suitable cylindrical substrate. Those provided with a conductive layer can be used favorably as the conductive support (31) of the present invention.

Next, the photosensitive layer will be described. As described above, as the photosensitive layer, a laminated type composed of the charge generation layer (35) and the charge transport layer (37) exhibits excellent characteristics in sensitivity and durability, and is used favorably.
The charge generation layer (35) has, as a charge generation material, a maximum diffraction peak at 27.2 ° as a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to CuKα characteristic X-rays (wavelength 1.542 mm). The crystal form). In particular, among the crystal types, there are further main peaks at 9.4 °, 9.6 °, 24.0 °, and the lowest diffraction angle has a peak at 7.3 °, A titanyl phthalocyanine crystal having no peak between the peak at 7.3 ° and the peak at 9.4 °, and having a peak at 26.3 ° is preferably used, and a peak intensity of 26.3 ° is obtained. A titanyl phthalocyanine crystal having a maximum diffraction peak of 27.2 ° in the range of 0.1 to 5% is particularly preferably used. Further, the average particle size of the primary particles of this crystal is less than 0.3 μm (preferably 0.25 μm or less, more preferably 0.2 μm or less), which makes the effect of the present invention more remarkable, It is an effective means.

In the charge generation layer (35), the pigment is dispersed in a suitable solvent together with a binder resin as necessary using a ball mill, an attritor, a sand mill, an ultrasonic wave, etc., and this is coated on a conductive support. It is formed by drying.
The binder resin used for the charge generation layer (35) as required may be polyamide, polyurethane, epoxy resin, polyketone, polycarbonate, silicon resin, acrylic resin, polyvinyl butyral, polyvinyl formal, polyvinyl ketone, polystyrene, polysulfone, poly -N-vinyl carbazole, polyacrylamide, polyvinyl benzal, polyester, phenoxy resin, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyphenylene oxide, polyamide, polyvinyl pyridine, cellulosic resin, casein, polyvinyl alcohol, polyvinyl pyrrolidone Etc. The amount of the binder resin is suitably 0 to 500 parts by weight, preferably 10 to 300 parts by weight with respect to 100 parts by weight of the charge generating material.

  Examples of the solvent used here 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 coating method for the coating solution, a dip coating method, spray coating, beat coating, nozzle coating, spinner coating, ring coating, or the like can be used. The film thickness of the charge generation layer (35) is suitably about 0.01 to 5 μm, preferably 0.1 to 2 μm.

The charge transport layer (37) can be formed by dissolving or dispersing a charge transport material and a binder resin in a suitable solvent, and applying and drying the solution on the charge generation layer. Moreover, a plasticizer, a leveling agent, antioxidant, etc. can also be added as needed.
Charge transport materials include hole transport materials and electron transport materials.
Examples of the electron transporting material include chloroanil, bromoanil, 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-tri Examples thereof include electron-accepting substances such as nitrodibenzothiophene-5,5-dioxide and benzoquinone derivatives.

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

Binder resins include polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, poly Vinylidene chloride, polyarate, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly-N-vinylcarbazole, acrylic resin, silicone resin, epoxy resin, melamine resin, urethane resin, phenol resin And thermoplastic or thermosetting resins such as alkyd resins.
The amount of the charge transport material is appropriately 20 to 300 parts by weight, preferably 40 to 150 parts by weight, based on 100 parts by weight of the binder resin. 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 for the purpose of reducing the environmental load. Specifically, cyclic ethers such as tetrahydrofuran, dioxolane and dioxane, aromatic hydrocarbons such as toluene and xylene, and derivatives thereof are preferably used.

  In addition, a polymer charge transport material having a function as a charge transport material and a function of a binder resin is also preferably used for the charge transport layer. The charge transport layer composed of these polymer charge transport materials is excellent in wear resistance. As the polymer charge transport material, known materials can be used, and in particular, a polycarbonate containing a triarylamine structure in the main chain and / or side chain is preferably used. Among these, 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. Substituted aryl group, o, p, q are each independently an integer of 0-4, k, j are compositions, 0.1 ≦ k ≦ 1, 0 ≦ j ≦ 0.9, n is the number of repeating units Represents 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 represents a substituted or unsubstituted alkyl group, aryl group or halogen atom. l and m are integers of 0 to 4, Y is a single bond, a linear, branched or cyclic alkylene group having 1 to 12 carbon atoms, —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 represents an integer of 1 to 20, b represents an integer of 1 to 2000, R ₁₀₃ and R ₁₀₄ 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_１Ａｒ_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 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 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、ｐは１〜５の整数を表わす。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 are substituted or unsubstituted aryl groups, Ar ₇ , Ar ₈ and Ar ₉ are the same or different arylene groups, and p represents an integer of 1 to 5. X, k, j and n are the same as in the case of 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 formula (I). 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, or a vinylene group may be the same or different. X, k, j and n are the same as in the case of 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 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 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 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 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.

Further, as the polymer charge transport material used in the charge transport layer, in addition to the polymer charge transport material described above, in the state of the monomer or oligomer having an electron donating group at the time of film formation of the charge transport layer, A polymer having a two-dimensional or three-dimensional crosslinked structure is finally included by carrying out a curing reaction or a crosslinking reaction.
A charge transport layer composed of a polymer having these electron donating groups or a polymer having a crosslinked structure is excellent in wear resistance. Usually, in the electrophotographic process, since the charging potential (unexposed portion potential) is constant, if the surface layer of the photoreceptor is worn by repeated use, the electric field strength applied to the photoreceptor increases accordingly. As the electric field strength increases, the occurrence frequency of scumming increases. Therefore, the high wear resistance of the photosensitive member is advantageous for scumming. The charge transport layer composed of a polymer having these electron donating groups is a polymer compound, so it has excellent film-forming properties and has a charge transport site compared to a charge transport layer composed of a low molecular weight dispersed polymer. It can be configured with high density and has excellent charge transport capability. For this reason, a photoreceptor having a charge transport layer using a polymer charge transport material can be expected to have a high response speed.
Examples of 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 cross-linked polymer having an electron donating group as disclosed in JP-A-206723 and JP-A No. 2001-34001.

  In the present invention, a plasticizer or a leveling agent may be added to the charge transport layer (37). As the plasticizer, those used as general plasticizers such as dibutyl phthalate and dioctyl phthalate can be used as they are, and the amount used 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, polymers or oligomers having a perfluoroalkyl group in the side chain are used, and the amount used is 0 to 0 with respect to the binder resin. 1% by weight is suitable.

In the electrophotographic photoreceptor of the present invention, an intermediate layer can be provided between the conductive support (31) and the photosensitive layer. In general, the intermediate layer is mainly composed of a resin. However, considering that the photosensitive layer is coated with a solvent on these resins, it is desirable that the resin be a resin having high solvent resistance with respect to a general organic solvent. . Examples of such resins include water-soluble resins such as polyvinyl alcohol, casein, and sodium polyacrylate, alcohol-soluble resins such as copolymer nylon and methoxymethylated nylon, polyurethane, melamine resin, phenol resin, alkyd-melamine resin, and epoxy. Examples thereof include a curable resin that forms a three-dimensional network structure such as a resin. Further, fine powder pigments of metal oxides exemplified by titanium oxide, silica, alumina, zirconium oxide, tin oxide, indium oxide and the like may be added to the intermediate layer in order to prevent moire and reduce residual potential.
These intermediate layers can be formed by using an appropriate solvent and coating method like the above-mentioned photosensitive layer. Furthermore, 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, in the intermediate layer of the present invention, Al ₂ O ₃ is provided by anodic oxidation, organic substances such as polyparaxylylene (parylene), SiO ₂ , SnO ₂ , TiO ₂ , ITO, CeO _2, etc. Those provided with an inorganic material by a vacuum thin film forming method can also be used favorably. In addition, known ones 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. In recent years, computers have been used on a daily basis, and it has been desired to reduce the size of the apparatus together with high-speed output by a printer. Therefore, by providing a protective layer and improving the durability, the photosensitive member of the present invention having high sensitivity and no abnormal defects can be used effectively.
That is, in the photoreceptor of the present invention, the protective layer (39) may be provided on the photosensitive layer. Materials used for the protective layer (39) include ABS resin, ACS resin, olefin-vinyl monomer copolymer, chlorinated polyether, allyl resin, phenol resin, polyacetal, polyamide, polyamideimide, polyacrylate, polyallylsulfone. , Polybutylene, polybutylene terephthalate, polycarbonate, polyarylate, polyethersulfone, polyethylene, polyethylene terephthalate, polyimide, acrylic resin, polymethylbenten, polypropylene, polyphenylene oxide, polysulfone, polystyrene, AS resin, butadiene-styrene copolymer, polyurethane , Resins such as polyvinyl chloride, polyvinylidene chloride, and epoxy resin. Of these, polycarbonate or polyarylate can be most preferably used.

  Other protective layers include fluorine resins such as polytetrafluoroethylene, silicone resins, and inorganic fillers such as titanium oxide, tin oxide, potassium titanate, and silica for the purpose of improving wear resistance. What disperse | distributed the filler etc. can be added.

  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. Metal powders such as copper, tin, aluminum and indium, metal oxides such as silica, tin oxide, zinc oxide, titanium oxide, indium oxide, antimony oxide, bismuth oxide, tin oxide doped with antimony, tin-doped indium oxide And inorganic materials such as potassium titanate. In particular, it is advantageous to use an inorganic material among them from the viewpoint of the hardness of the filler. In particular, silica, titanium oxide, and alumina can be used effectively.

The filler concentration in the protective layer varies depending on the type of filler used and also on the electrophotographic process conditions using the photoconductor, but the ratio of filler to the total solid content on the outermost layer side of the protective layer is preferably 5% by weight or more, preferably It is 10% by weight or more and 50% by weight or less, preferably about 30% by weight or less.
Further, the volume average particle size of the filler used is preferably in the range of 0.1 μm to 2 μm, and preferably in the range of 0.3 μm to 1 μm. In this case, if the average particle size is too small, the wear resistance is not sufficiently exhibited, and if it is too large, the surface property of the coating film is deteriorated or the coating film itself cannot be formed.

  In addition, unless otherwise indicated, the average particle diameter of the filler in this invention is a volume average particle diameter, and is calculated | required with the ultracentrifugal automatic particle size distribution measuring apparatus: CAPA-700 (made by Horiba Seisakusho). At this time, the particle size (Median system) corresponding to 50% of the cumulative distribution was calculated. In addition, it is important that the standard deviation of each particle measured simultaneously is 1 μm or less. If the standard deviation is larger than this, the particle size distribution may be too wide, and the effects of the present invention may not be obtained remarkably.

Further, the pH of the filler used in the present invention greatly affects the resolution and the dispersibility of the filler. One possible reason is that hydrochloric acid or the like remains in the filler, particularly the metal oxide, during production. When the remaining amount is large, the occurrence of image blur is unavoidable, and depending on the remaining amount, the dispersibility of the filler may be affected.
Another reason is due to the difference in chargeability on the surface of the filler, particularly the metal oxide. Usually, particles dispersed in a liquid are charged positively or negatively, and ions having opposite charges gather to try to keep it electrically neutral, and an electric double layer is formed there. The dispersed state of the particles is stabilized. The potential (zeta potential) gradually decreases with increasing distance from the particle, and the potential in a region that is sufficiently away from the particle and electrically neutral is 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 they approach 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 configuration of the present invention, the filler having a pH at the isoelectric point of at least 5 is preferably from the viewpoint of image blur suppression, and the more basic the filler, the higher the effect. It was confirmed that there was. A filler exhibiting basicity having a high pH at the isoelectric point has a higher zeta potential when the system is acidic, thereby improving dispersibility and its stability.
Here, the pH of the filler in the present invention is the 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.

Furthermore, as the filler that is less likely to cause image blurring, a filler having high electrical insulation (specific resistance is 10 ¹⁰ Ω · cm or more) is preferable, and the filler having a pH of 5 or more or the filler having a dielectric constant of 5 or more. 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 can be used alone, or two or more fillers having a pH of 5 or less and a filler having a pH of 5 or more can be mixed. 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-type alumina, which has a high insulation property, high thermal stability, and high wear resistance, is a hexagonal close-packed structure, which suppresses image blur and improves wear resistance. Is particularly useful from

The specific resistance of the filler used in the present invention is defined as follows. Since the specific resistance value of a powder such as a filler varies depending on the filling rate, it is necessary to measure under certain conditions. In the present invention, the specific resistance value of the filler is determined using an apparatus having the same configuration as the measuring apparatus shown in Japanese Patent Laid-Open Nos. 5-94049 (FIG. 1) and 5-113688 (FIG. 1). Measured and used this value. In the measuring device, the electrode area is 4.0 cm ² . Prior to measurement, a load of 4 kg is applied to one electrode for 1 minute, and the sample amount is adjusted so that the distance between the electrodes is 4 mm. At the time of measurement, the measurement is performed with the weight of the upper electrode (1 kg) loaded, and the applied voltage is measured at 100V. The area of 10 ⁶ Ω · cm or more was measured with a HIGH RESISTER METER (Yokogawa Hewlett Packard), and the area below it was measured with a digital multimeter (Fluke). The specific resistance value thus obtained is defined as the specific resistance value in the present invention.
The dielectric constant of the filler was measured as follows. Using a cell similar to the measurement of the specific resistance as described above, after applying a load, the capacitance was measured, and the dielectric constant was determined from this. For the measurement of the capacitance, a dielectric loss measuring device (Ando Electric) was used.

Further, these fillers can be surface-treated with at least one kind of surface treatment agent, and it is preferable from the viewpoint of dispersibility of the fillers. Lowering the dispersibility of the filler not only increases the residual potential, but also lowers the transparency of the coating, causes defects in the coating, and lowers the wear resistance. It can develop into a big problem. As the surface treatment agent, all conventionally used surface treatment agents can be used, but a surface treatment agent capable of maintaining the insulating properties of the filler is preferable. For example, a titanate coupling agent, an aluminum coupling agent, a zircoaluminate coupling agent, a higher fatty acid, etc., or a mixing treatment of these 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. The treatment with the silane coupling agent is strongly influenced by image blur, but the influence may be suppressed by performing a mixing treatment of the surface treatment agent and the silane coupling agent. The surface treatment amount varies depending on the average primary particle size of the filler used, but is preferably 3 to 30 wt%, more preferably 5 to 20 wt%. If the surface treatment amount is less than this, the filler dispersion effect cannot be obtained, and if it is too much, the residual potential is significantly increased. These filler materials may be 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 to be used with respect 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 primary particle level and has less aggregates.

Further, the protective layer (39) may contain a charge transport material for reducing residual potential and improving responsiveness. As the charge transport material, the materials described in the description of the charge transport 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. In order to improve wear resistance, it is an effective means to reduce the concentration of the surface side. The concentration here refers to the ratio of the weight of the low molecular charge transporting material to the total weight of all the materials constituting the protective layer, and the concentration gradient is a gradient that lowers the concentration on the surface side in the above weight ratio. It shows that. The use of a polymer charge transport material is very advantageous in terms of enhancing the durability of the photoreceptor.
As a method for forming the protective layer, a normal coating method is employed. In addition, about 0.1-10 micrometers is suitable for the thickness of a protective layer. In addition to the above, a known material such as a-C or a-SiC formed by a vacuum thin film forming method can be used as the protective layer.

As described above, the use of a polymer charge transport material for the photosensitive layer (charge transport layer) or the provision of a protective layer on the surface of the photoreceptor increases the durability (wear resistance) of each photoreceptor. In addition, when used in a tandem type full-color image forming apparatus as described later, a new effect not found in the monochrome image forming apparatus is also produced.
In the case of a full-color image, various types of images are input, but on the contrary, a typical image may also be input. For example, the presence of a seal in a Japanese document or the like. Something like indicia is usually located towards the edge of the image area, and the colors used are also limited. In a state in which a random image is always written, image writing, development, and transfer are performed on the photoconductor in the image forming element on average. When many image formations are repeated or only a specific image forming element is used, the durability balance is lost. When a photoconductor having a low surface durability (physical / chemical / mechanical) is used in such a state, this difference becomes prominent and easily causes an image problem. On the other hand, when the photoconductor is made highly durable, the amount of such local change is small, and as a result, it becomes difficult to appear as a defect on the image, so that high durability is achieved and the stability of the output image is improved. This is very effective.

Hereinafter, although an example is given and the present invention is explained, the present invention is not restricted by an example. All parts are parts by weight.
First, a synthesis example of the charge generation material used in the present invention will be described.
(Reference Synthesis Example 1)
292 g of 1,3-diiminoisoindoline and 2000 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 by stirring for 5 hours while maintaining the reaction temperature between 170 ° C. and 180 ° C. After completion of the reaction, the mixture was allowed to cool, and then the precipitate was filtered, washed with chloroform until the powder turned blue, then washed several times with methanol, further washed several times with hot water at 80 ° C., and dried. Crude titanyl phthalocyanine was obtained. Dissolve the crude titanyl phthalocyanine in 20 times the amount of concentrated sulfuric acid, add dropwise to 100 times the amount of ice water with stirring, filter the precipitated crystals, and then repeat washing with water until the washing solution becomes neutral. (Water paste) was obtained. 50 g of the obtained wet cake (water paste) was put into 500 g of tetrahydrofuran, stirred for 4 hours, filtered and dried to obtain titanyl phthalocyanine crystals.
Further, 30 g of this titanyl phthalocyanine crystal was immersed in 300 g of tetrahydrofuran, and a second crystal conversion was performed. After leaving it immersed for 12 hours, it 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 designated as Pigment 1.

(Reference Synthesis Example 2)
The treatment was performed in the same manner as in Reference Synthesis Example 1 except that the second crystal conversion operation in Reference Synthesis Example 1 was changed to the following conditions to obtain a titanyl phthalocyanine crystal of the present invention (see FIG. 10). This is designated as Pigment 2.
(Second crystal conversion process)
30 g of titanyl phthalocyanine crystals subjected to the first crystal conversion treatment were subjected to mechanical shearing force for 5 minutes by a commercially available mixer, and then the powder was taken out.

( Reference Synthesis Example 3 )
The treatment was performed in the same manner as in Reference Synthesis Example 1 except that the second crystal conversion operation in Reference 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 titanyl phthalocyanine crystals subjected to the first crystal conversion treatment were put into a φ90 mm glass pot together with 2 kg of φ6 mm zirconia balls, and after dry milling for 10 minutes, the powder was taken out.

(Comparative Synthesis Example 1)
The same treatment as in Reference Synthesis Example 1 was performed except that the second crystal conversion solvent in Reference Synthesis Example 1 was changed from tetrahydrofuran to methanol to obtain titanyl phthalocyanine crystals. This is designated as Pigment 4.

(Comparative Synthesis Example 2)
In Reference Synthesis Example 1 , 2-butanone was used in place of tetrahydrofuran as the first crystal conversion solvent, and the treatment was performed in the same manner as in Reference Synthesis Example 1 except that the second crystal conversion was not performed. Obtained. This is designated as Pigment 5.

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

For Reference Synthesis Examples 1 to 3 , since the same X-ray diffraction spectrum was shown in each case except for the peak intensity of 26.3 °, X of the titanyl phthalocyanine crystal obtained in Reference Synthesis Example 2 as a representative example. A line diffraction spectrum is shown in FIG. 10 (the arrow in the figure is a 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 no peak was observed at 26.3 °.
The X-ray diffraction spectrum of the titanyl phthalocyanine crystal obtained in Comparative Synthesis Example 2 is shown in FIG. 12, and the lowest angle exists at 7.5 °.

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

(Comparative Synthesis Example 4)
A pigment was produced according to the method described in JP-A-3-269064 (Japanese Patent No. 2854682) and Production Example 1. That is, the wet cake prepared in Reference Synthesis Example 1 was dried, and 1 g of the dried product was stirred (50 ° C.) in a mixed solvent of 10 g of ion-exchanged water and 1 g of monochlorobenzene for 1 hour, and then methanol and ion-exchanged water. The pigment was obtained by washing and drying. This is designated as Pigment 7.

(Comparative Synthesis Example 5)
A pigment was produced according to the method described in the production example of JP-A-2-8256 (Japanese Patent Publication No. 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 completion of the dropping, the temperature was gradually raised to 200 ° C., and the reaction was carried out by stirring for 3 hours while maintaining the reaction temperature between 200 ° C. and 220 ° C. After completion of the reaction, the mixture was allowed to cool to 130 ° C. and filtered while hot, then washed with 1-chloronaphthalene until the powder turned blue, then washed several times with methanol, and further 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 (Japanese Patent Publication No. 7-97221) and Synthesis Example 1. That is, 5 parts of α-type TiOPc was subjected to 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 dilute sulfuric acid aqueous solution, washed with ion-exchanged water until the acid content disappeared, and dried to obtain a pigment. This is designated as Pigment 9.

(Comparative Synthesis Example 7)
A pigment was prepared according to the method described in JP-A No. 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 then 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 stirred at a high speed, and the precipitated crystals are filtered. The crystals are washed with distilled water until no acid remains, and a wet cake is obtained. 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 (Patent No. 3005052) and Synthesis Example 2. That is, by mixing the above wet cake 10 parts prepared in Reference Synthesis Example 1 in 15 parts of diethylene glycol 7 parts of sodium chloride, was subjected to 60 hours milling treatment by an automatic mortar under heating at 80 ° C.. Next, sufficient washing was performed to completely remove sodium chloride and diethylene glycol contained in the treated product. After drying this under reduced pressure, 200 parts of cyclohexanone and glass beads having a diameter of 1 mm were added, and the mixture was treated with a sand mill for 30 minutes to obtain a pigment. This is designated as Pigment 11.

(Comparative Synthesis Example 9)
A pigment was prepared according to the method described in JP-A No. 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 and filtered until neutral, and dried. Further, this was dispersed with THF in a ball mill for 10 hours, filtered and dried to obtain a pigment powder. This is designated as Pigment 12.

(Comparative Synthesis Example 10)
A pigment was prepared according to the method described in JP-A No. 5-134437, Production Example 1 and Production Example 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 dropping, the temperature was raised, and the mixture was reacted at 200 to 220 ° C. for 3 hours with stirring, then allowed to cool, filtered hot at 100 to 130 ° C., and washed with 200 ml of α-chloronaphthalene heated to 100 ° C. Furthermore, the hot-washing process (100 degreeC, 1 hour) was performed 3 times with 200 ml N-methylpyrrolidone. Subsequently, the suspension was washed with 300 ml of methanol at room temperature, and further washed with 500 ml of methanol for 1 hour. This is designated as phthalocyanine 1.
Next, phthalocyanine 1 was ground in a sand grind mill for 20 hours, then placed in a suspension of 400 ml of water and 40 ml of o-dichlorobenzene, and heat-treated at 60 ° C. for 1 hour. This is designated as phthalocyanine 2.
Further, according to Example 1 of JP-A-5-134437, 6 parts by weight and 4 parts by weight of phthalocyanine 1 and phthalocyanine 2 were mixed, 200 parts by weight of n-propanol was added, and pulverized with a sand grind mill for 10 hours. Then, atomization dispersion treatment was performed. This was dried to obtain phthalocyanine powder. This is designated as Pigment 13.

( Synthesis Example 1 )
According to the method of Reference Synthesis Example 1 , a titanyl phthalocyanine pigment water paste was synthesized, and crystal conversion was performed as follows to obtain phthalocyanine crystals having smaller primary particles than those of Synthesis Example 1.
Add 1500 parts of tetrahydrofuran to 60 parts of the water paste before crystal conversion obtained in Reference Synthesis Example 1 and stir vigorously (2000 rpm) with a homomixer (Kennis, MARKIIf model) at room temperature. When the color changed to light blue (20 minutes after the start of stirring), stirring was stopped and filtration under reduced pressure was immediately performed. The crystals obtained on the filter were washed with tetrahydrofuran to obtain a pigment wet cake. This was dried under reduced pressure (5 mmHg) at 70 ° C. for 2 days to obtain 58 parts of titanyl phthalocyanine crystals.
Further, 30 g of this titanyl phthalocyanine crystal was immersed in 300 g of tetrahydrofuran, and a second crystal conversion was performed. After leaving it immersed for 12 hours, it 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 designated as Pigment 14.

Part of the pre-crystallized titanyl phthalocyanine (water paste) prepared in Reference Synthesis Example 1 was diluted with ion-exchanged water to approximately 1% by weight, and the surface was scooped with a conductive copper net, and titanyl The particle size of phthalocyanine was observed with a transmission electron microscope (TEM, Hitachi: H-9000NAR) at a magnification of 75000 times. The average particle size was determined as follows.
The TEM image observed as described above is taken as a TEM photograph, and 30 titanyl phthalocyanine particles (a shape close to a needle shape) projected are arbitrarily selected, and the size of each major axis is measured. The arithmetic average of the major diameters of the 30 individuals measured was determined as the average particle size.
The average particle size in the water paste in Reference Synthesis Example 1 determined by the above method was 0.06 μm.

In addition, the titanyl phthalocyanine crystal after crystal conversion just before filtration in Reference Synthesis Example 1 and Synthesis Example 1 was diluted with tetrahydrofuran to approximately 1% by weight, and observed in the same manner as the above method. The average particle size obtained as described above is shown in Table 1. In addition, the titanyl phthalocyanine crystal produced in Reference Synthesis Example 1 and Synthesis Example 1 did not necessarily have the same shape of all crystals (a shape close to a triangle, a shape close to a square, etc.). For this reason, the calculation was performed with the length of the largest diagonal line of the crystal as the major axis.

また、以上の比較合成例３〜１０で作製した顔料は、先程と同様の方法でＸ線回折スペクトルを測定し、それぞれの公報に記載のスペクトルと同様であることを確認した。表２にそれぞれのＸ線回折スペクトルと参考合成例１で得られた顔料のＸ線回折スペクトルのピーク位置の特徴を示す。
なお、表２中の２６．３°のピーク強度とは、前述の通り、２６．３°のピーク強度の２７．２°のピーク強度の比である。この計算に際して、図１１のように２６．３°のピークが明確に観測されない場合には、ピーク強度＝０として計算を行なった。また、合成例１で作製した顔料のＸ線回折スペクトルは、２６．３°のピーク強度以外は、参考合成例１で作製した顔料のスペクトルと一致した。表２にそれぞれのＸ線回折スペクトルと参考合成例１で得られた顔料のＸ線回折スペクトルのピーク位置の特徴を示す。

In addition, the pigments produced in the above Comparative Synthesis Examples 3 to 10 were measured for X-ray diffraction spectra by the same method as described above, and confirmed to be the same as the spectra described in the respective publications. Table 2 shows the characteristics of each X-ray diffraction spectrum and the peak position of the X-ray diffraction spectrum of the pigment obtained in Reference Synthesis Example 1 .
The peak intensity at 26.3 ° in Table 2 is the ratio of the peak intensity at 27.2 ° 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. 11, the calculation was performed with the peak intensity = 0. Further, X-ray diffraction spectrum of the pigment prepared in Synthesis Example 1, except the peak intensity of 26.3 °, were consistent with the spectrum of the pigment prepared in Reference Synthesis Example 1. Table 2 shows the characteristics of each X-ray diffraction spectrum and the peak position of the X-ray diffraction spectrum of the pigment obtained in Reference Synthesis Example 1 .

(Photoreceptor Preparation Example 1)
An undercoat layer coating solution, a charge generation layer coating solution, and a charge transport layer coating solution having the following composition were sequentially applied and dried on an aluminum cylinder (JIS1050) having a diameter of 60 mm, and an undercoat layer of 3.5 μm, A charge generation layer and a charge transport layer of 25 μm were formed to produce a laminated photoreceptor (referred to as photoreceptor 1). The film thickness of the charge generation layer was adjusted so that the transmittance of the charge generation layer at 780 nm was 20%. The charge generation layer transmittance was measured by applying a charge generation layer coating solution having the following composition to an aluminum cylinder wrapped with a polyethylene terephthalate film under the same conditions as the preparation of the photoreceptor, and coating the charge generation layer as a comparative control. The transmittance was measured at 780 nm using a commercially available spectrophotometer (Shimadzu: UV-3100).
◎ Undercoat layer coating solution Titanium oxide (CR-EL: manufactured by Ishihara Sangyo Co., Ltd.) 70 parts Alkyd resin 15 parts (Beckolite M6401-50-S (solid content 50%),
Dainippon Ink & Chemicals)
Melamine resin 10 parts (Super Becamine L-121-60 (solid content 60%),
Dainippon Ink & Chemicals)
2-Butanone 100 parts Charge generation layer coating solution A dispersion having the following composition was prepared by bead milling under the conditions shown below.
Titanyl phthalocyanine pigment prepared in Reference Synthesis Example 1 15 parts polyvinyl butyral (manufactured by Sekisui Chemical: BX-1) 10 parts 2-butanone 280 parts Dissolve polyvinyl butyral in a commercially available bead mill disperser using PSZ balls with a diameter of 0.5 mm. The 2-butanone and the pigment were all charged, and the rotor rotational speed was 1500 r. p. m. For 30 minutes to prepare a dispersion.
The particle size distribution of the pigment particles in this dispersion was measured by HORIBA, Ltd .: CAPA-700. As a result, the average particle size was 0.29 μm, and the standard deviation was 0.18 μm.
◎ Charge transport layer coating solution Polycarbonate (TS2050: manufactured by Teijin Chemicals Ltd.) 10 parts Charge transport material of the following structural formula 7 parts

塩化メチレン ８０部

80 parts of methylene chloride

(Photosensitive member production examples 2 to 14)
The titanyl phthalocyanine pigments (prepared in Reference Synthesis Example 1 ) used in the charge generation layer coating solution used in Photoreceptor Preparation Example 1 were prepared in Reference Synthesis Examples 2 and 3, Synthesis Example 1 and Comparative Synthesis Examples 1 to 10, respectively. A photoconductor was prepared in the same manner as in Photoconductor Preparation Example 1 except that the titanyl phthalocyanine pigment was changed. In addition, the film 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 Photoreceptor Preparation Example 1.

(Photoreceptor Preparation Example 15)
The charge generation layer coating solution used in Photoreceptor Preparation Example 1 was filtered using a cotton wind cartridge filter, TCW-3-CS (effective pore size 3 μm) manufactured by Advantech before coating. During filtration, a pump was used and filtration was performed in a pressurized state.

(Photoreceptor Production Example 16)
The charge generation layer coating solution used in Photoconductor Preparation Example 1 was filtered using a cotton wind cartridge filter, TCW-1-CS (effective pore size 1 μm) manufactured by Advantech before coating. During filtration, a pump was used and filtration was performed in a pressurized state.

(Photoreceptor Preparation Example 17)
The charge generation layer coating solution used in Photoreceptor Preparation Example 1 was filtered using a cotton wind cartridge filter, TCW-5-CS (effective pore size 5 μm) manufactured by Advantech before coating. During filtration, a pump was used and filtration was performed in a pressurized state.

(Reference Examples 1-6, Example 1 and Comparative Examples 1-27)
The electrophotographic photoconductors of photoconductor production examples 1 to 17 produced as described above are mounted on the electrophotographic apparatus shown in FIG. 2, and an image exposure light source is a semiconductor laser of 780 nm (image writing by a polygon mirror) as a charging member. Using a contact-type charging roller and a transfer belt as a transfer member, using a chart with a writing rate of 6% under the following charging and transfer conditions, evaluating an image after continuous 200,000 sheets printing, The presence or absence was confirmed (the test environment was 22 ° C.-55% RH). At this time, the transfer current was controlled by a circuit as shown in FIG. The evaluation was carried out in 4 stages. Very good ones were indicated by 、, good ones were indicated by ○, slightly inferior ones were indicated by Δ, and very bad ones were indicated by ×. The above results are shown in Table 3-1.
Charging conditions:
DC bias: -900V
AC bias: 2.0 kV (Peak to peak), frequency: 1.5 kHz
Transfer conditions:
Two conditions of 75μA and 60μA
Further, after the above test at 22 ° C.-55% RH, the above charging conditions are maintained (transfer conditions are only 75 μA), 20,000 sheets at 10 ° C.-15% RH, and 20,000 sheets at 30 ° C.-90% RH. The running test was conducted, and image evaluation was performed in the same manner for each image after 20,000 sheets. The results are shown in Table 3-2 and Table 3-3, respectively.
<Evaluation results under 22 ° C.-55% RH environment>

＜１０℃−１５％ＲＨ環境下での評価結果＞

<Evaluation results under 10 ° C-15% RH environment>

参考例１〜３の画像はいずれも良好な画像であったが、１０℃−１５％ＲＨ環境下での２万枚後の画像において、参考例２の画像は、参考例１および参考例３の画像に比べて僅かではあるが、画像濃度が低かった。
＜３０℃−９０％ＲＨ環境下での評価結果＞

Although images of Reference Examples 1 to 3 were good images both in 20,000 sheets after image under 10 ° C. -15% RH environment, the image of Reference Example 2, Reference Example 1 and Reference Example 3 The image density was low although it was slightly compared with the image of.
<Evaluation results in a 30 ° C.-90% RH environment>

(Photoreceptor Preparation Example 18)
A photoconductor was prepared in the same manner as in Photoconductor Preparation Example 1 except that the charge transport layer coating solution in Photoconductor Preparation Example 1 was changed to one having the following composition.
◎ Charge transport layer coating solution 10 parts of polymer charge transport material having the following composition (weight average molecular weight: about 135,000)

下記構造の添加剤 ０．５部

0.5 parts of additive with the following structure

塩化メチレン １００部

100 parts methylene chloride

(Photoreceptor Preparation Example 19)
Similar to Photoreceptor Preparation Example 1 except that the thickness of the charge transport layer in Photoreceptor Preparation Example 1 was 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 photoreceptor was prepared.
◎ Protective layer coating solution Polycarbonate (TS2050: manufactured by Teijin Chemicals Ltd.) 10 parts Charge transport material of the following structural formula: 7 parts

アルミナ微粒子 ４部
（比抵抗：２．５×１０^１２Ω・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

(Photoreceptor Preparation Example 20)
A photoconductor was prepared in the same manner as in Photoconductor Preparation Example 19 except that the alumina fine particles in the protective layer coating solution in Photoconductor Preparation Example 19 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 Preparation Example 21)
A photoconductor was prepared in the same manner as in Photoconductor Preparation Example 19 except that the alumina fine particles in the protective layer coating solution in Photoconductor Preparation Example 19 were changed to the following.
4 parts of tin oxide-antimony oxide powder (specific resistance: 10 ⁶ Ω · cm, average primary particle size 0.4 μm)

(Photoconductor Preparation Example 22)
The aluminum cylinder (JIS 1050) in photoreceptor preparation example 1 is subjected to the following anodic oxide film treatment, and then a charge generation layer and a charge transport layer are provided in the same manner as in photoreceptor preparation example 1 without providing an undercoat layer. Was made.
◎ Anodic oxide film treatment After mirror polishing of the support surface, degreasing and water washing, immersion in an electrolytic bath with a liquid temperature of 20 ° C and sulfuric acid of 15 vol%, and an anodic oxide film treatment at an electrolytic voltage of 15 V for 30 minutes. Was done. Further, after washing with water, 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 on which a 7 μm anodic oxide film was formed.

( Reference Examples 7 to 17, Example 2 and Comparative Examples 28 to 37)
The electrophotographic photoconductors of the photoconductor production examples 1 to 22 produced as described above are mounted on the electrophotographic apparatus shown in FIG. 2, and an image exposure light source is a semiconductor laser of 780 nm (image writing by a polygon mirror), and a charging member. As a charging member, a charging member for close placement in which an insulating tape having a thickness of 50 μm is wound around both ends of a charging roller as shown in FIG. 3 (the gap between the surface of the photosensitive member and the charging member is 50 μm) is used. Under the transfer conditions, using a chart with a writing rate of 6%, the presence or absence of background stains after continuous printing of 250,000 sheets and a halftone image were confirmed (the test environment is 22 ° C.-55% RH). At this time, the transfer current was controlled by a circuit as shown in FIG. In addition, the evaluation of the background stain was performed in four stages, and an extremely good one was indicated by 、, a good one by ○, a slightly inferior by Δ, and a very bad one by ×. In addition, the amount of abrasion of the photosensitive layer after printing 250,000 sheets (the amount of abrasion of the protective layer when a protective layer is provided) was measured. The results are shown in Table 4.
Charging conditions:
DC bias: -900V
AC bias: 2.0 kV (Peak to peak), frequency: 1.5 kHz
Transfer conditions:
90μA

( Reference Example 18 )
In Reference Example 7 , after a paper passing test of 250,000 sheets, a halftone image was output in a 30 ° C.-90% RH environment, and image evaluation was performed.

( Reference Example 19 )
The charging member in Reference Example 7 was changed from a charging member for close placement to a scorotron charger, and the surface potential of the non-image portion of the photoreceptor was set to be the same (−900 V) as in Reference Example 7 . Without changing the other conditions, the paper passing test of 250,000 sheets was performed in the same manner as in Reference Example 7 . After the paper passing test, as in Reference Example 18 , a halftone image was output in a 30 ° C.-90% RH environment, and image evaluation was performed.

( Reference Example 20 )
The charging member in Reference Example 7 was changed from the proximity charging member to the contact charging member (no gap), and the charging conditions were set to the same conditions as in Reference Example 7 . Without changing the other conditions, the paper passing test of 250,000 sheets was performed in the same manner as in Reference Example 7 . After the paper passing test, as in Reference Example 18 , a halftone image was output in a 30 ° C.-90% RH environment, and image evaluation was performed.

( Reference Example 21 )
Evaluation was performed in the same manner as in Reference Example 20 except that the charging conditions in Reference Example 20 were changed as follows.
Charging conditions:
DC bias: −1600 V (surface potential of the non-image portion of the photoreceptor in the initial state is −900 V)
AC bias: None

( Reference Example 22 )
Evaluation was performed in the same manner as in Reference Example 7 except that the charging conditions in Reference Example 7 were changed as follows. After a paper passing test of 250,000 sheets, a halftone image was output in a 30 ° C.-90% RH environment in the same manner as in Reference Example 18, and image evaluation was performed.
Charging conditions:
DC bias: −1600 V (surface potential of the non-image portion of the photoreceptor in the initial state is −900 V)
AC bias: None

( Reference Example 23 )
Evaluation was performed in the same manner as in Reference Example 7 except that the gap of the charging member (proximity charging roller) used in Reference Example 7 was changed to 100 μm. After a paper passing test of 250,000 sheets, a halftone image was output in a 30 ° C.-90% RH environment in the same manner as in Reference Example 18, and image evaluation was performed.

( Reference Example 24 )
Evaluation was performed in the same manner as in Reference Example 7 except that the gap of the charging member (proximity charging roller) used in Reference Example 7 was changed to 150 μm. After a paper passing test of 250,000 sheets, a halftone image was output in a 30 ° C.-90% RH environment in the same manner as in Reference Example 18, and image evaluation was performed.

( Reference Example 25 )
Evaluation was performed in the same manner as in Reference Example 7 except that the gap of the charging member (proximity charging roller) used in Reference Example 7 was changed to 250 μm. After a paper passing test of 250,000 sheets, a halftone image was output in a 30 ° C.-90% RH environment in the same manner as in Reference Example 18, and image evaluation was performed.

( Reference Example 26 )
In Example 2 , after a paper passing test of 250,000 sheets, a halftone image was output in a 30 ° C.-90% RH environment, and image evaluation was performed.

( Reference Example 27 )
In Reference Example 10 , after a paper passing test of 250,000 sheets, a halftone image was output in a 30 ° C.-90% RH environment, and image evaluation was performed.
The evaluation results in the above Reference Examples 18 to 27 are shown in Table 5.

(Photoconductor Preparation Example 23)
A photoconductor was prepared in the same manner as in Photoconductor Preparation Example 1 except that the charge transport layer coating solution in Photoconductor Preparation Example 1 was changed to the following composition.
◎ Charge transport layer coating solution Polycarbonate (TS2050: manufactured by Teijin Chemicals Ltd.) 10 parts Charge transport material of the following structural formula 7 parts

テトラヒドロフラン ８０部

80 parts of tetrahydrofuran

(Photoconductor Preparation Example 24)
A photoconductor was prepared in the same manner as in Photoconductor Preparation Example 11 except that the charge transport layer coating solution in Photoconductor Preparation Example 11 was changed to the following composition.
◎ Charge transport layer coating solution Polycarbonate (TS2050: manufactured by Teijin Chemicals Ltd.) 10 parts Charge transport material of the following structural formula 7 parts

テトラヒドロフラン ８０部

80 parts of tetrahydrofuran

(Photoconductor Preparation Example 25)
A photoconductor was prepared in the same manner as in Photoconductor Preparation Example 1 except that the charge transport layer coating solution in Photoconductor Preparation Example 1 was changed to the following composition.
◎ Charge transport layer coating solution Polycarbonate (TS2050: manufactured by Teijin Chemicals Ltd.) 10 parts Charge transport material of the following structural formula 7 parts

ジオキソラン ８０部

80 parts of dioxolane

(Photoconductor Preparation Example 26)
A photoconductor was prepared in the same manner as in Photoconductor Preparation Example 1 except that the charge transport layer coating solution in Photoconductor Preparation Example 1 was changed to the following composition.
◎ Charge transport layer coating solution Polycarbonate (TS2050: manufactured by Teijin Chemicals Ltd.) 10 parts Charge transport material of the following structural formula 7 parts

テトラヒドロフラン ４０部
トルエン ４０部

Tetrahydrofuran 40 parts Toluene 40 parts

(Photoconductor Preparation Example 27)
A photoconductor was prepared in the same manner as in Photoconductor Preparation Example 4 except that the charge transport layer coating solution in Photoconductor Preparation Example 4 was changed to the following composition.
◎ Charge transport layer coating solution Polycarbonate (TS2050: manufactured by Teijin Chemicals Ltd.) 10 parts Charge transport material of the following structural formula 7 parts

テトラヒドロフラン ８０部

80 parts of tetrahydrofuran

(Photoreceptor Preparation Example 28)
A photoconductor was prepared in the same manner as in Photoconductor Preparation Example 14 except that the charge transport layer coating solution in Photoconductor Preparation Example 14 was changed to the following composition.
◎ Charge transport layer coating solution Polycarbonate (TS2050: manufactured by Teijin Chemicals Ltd.) 10 parts Charge transport material of the following structural formula 7 parts

テトラヒドロフラン ８０部

80 parts of tetrahydrofuran

( Examples 28-31, Example 3 and Comparative Example 38)
As in the case of Example 1, the photoconductors of photoconductor production examples 23 to 28 produced as described above were mounted on the electrophotographic apparatus shown in FIG. 2, and the image exposure light source was a 780 nm semiconductor laser (using a polygon mirror). For image writing, a contact-type charging roller was used as a charging member, and a halftone line image was output under the following charging and transfer conditions. At this time, the transfer current was controlled by a circuit as shown in FIG. The above results are shown in Table 6 together with Reference Example 1 and Comparative Example 7.
Charging conditions:
DC bias: -900V
AC bias: 2.0 kV (Peak to peak), frequency: 1.5 kHz
Transfer conditions:
110 μA

(Photoconductor Preparation Example 29)
The aluminum cylinder of the photoreceptor preparation example 1 was changed to one having a diameter of 30 mm, and a photoreceptor having the same composition as that of the photoreceptor preparation example 1 was prepared.

(Photoreceptor Preparation Example 30)
The aluminum cylinder of the photoreceptor preparation example 9 was changed to one having a diameter of 30 mm, and a photoreceptor having the same composition as that of the photoreceptor preparation example 9 was prepared.

(Photoreceptor Preparation Example 31)
The aluminum cylinder of the photoreceptor preparation example 10 was changed to one having a diameter of 30 mm, and a photoreceptor having the same composition as that of the photoreceptor preparation example 10 was prepared.

(Photoconductor Preparation Example 32)
The aluminum cylinder of the photoreceptor preparation example 4 was changed to one having a diameter of 30 mm, and a photoreceptor having the same composition as that of the photoreceptor preparation example 4 was prepared.

(Photoconductor Preparation Example 33)
The aluminum cylinder of the photoreceptor preparation example 15 was changed to one having a diameter of 30 mm, and a photoreceptor having the same composition as that of the photoreceptor preparation example 15 was prepared.

( Reference Examples 32-33, Example 4 and Comparative Examples 39-45)
The photoreceptors of Preparation Examples 29 to 33 prepared as described above were mounted on one electrophotographic apparatus process cartridge together with the charging member, and further mounted on the full-color electrophotographic apparatus shown in FIG. The four image forming elements were subjected to a test for passing through 200,000 full-color images under the process conditions shown below, followed by checking for missing characters, background smudges, and halftone image evaluation (the test environment was 22 ° C.-55). % RH). At this time, the transfer current was controlled by a circuit as shown in FIG. Character omission and background stain evaluation were performed in four stages. Very good ones were indicated by ◎, good ones were indicated by ○, slightly inferior ones by Δ, and very bad ones by x. The results are shown in Table 7.
Charging condition: DC bias -800V,
AC bias 1.5 kV (peak to peak),
Frequency 2.0kHz
Charging member: same as used in Reference Example 7
Writing: 780nm LD (using polygon mirror)
Transfer conditions: 2 conditions of 75 μA and 60 μA

  Finally, 7.3 ° which is the lowest angle peak of the Bragg angle θ, which is a feature of the titanyl phthalocyanine crystal used in the present invention, will be verified as to whether or not it is the same as the lowest angle 7.5 ° of known materials.

(Measurement Example 1)
A pigment prepared in the same manner as the pigment described in JP-A-61-239248 (having a maximum diffraction peak at 7.5 °) was used as the pigment obtained in Comparative Synthesis Example 1 (minimum angle 7.3 °). Weight% was added and mixed in a mortar, and the X-ray diffraction spectrum was measured in the same manner as before. The X-ray diffraction spectrum of Measurement Example 1 is shown in FIG.

(Measurement example 2)
3 was prepared in the same manner as the pigment described in JP-A-61-239248 (having a maximum diffraction peak at 7.5 °) as the pigment obtained in Comparative Synthesis Example 2 (minimum angle 7.5 °). Weight% was added and mixed in a mortar, and the X-ray diffraction spectrum was measured in the same manner as before. The X-ray diffraction spectrum of Measurement Example 2 is shown in FIG.

In the spectrum of FIG. 13, it can be seen that there are two independent peaks at 7.3 ° and 7.5 ° on the lower angle side, and at least the peaks at 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 minimum angle peak of 7.3 ° in the titanyl phthalocyanine crystal of the present invention is different from the 7.5 ° peak in the known titanyl phthalocyanine crystal.

It is a figure showing the relationship between transfer current and transfer efficiency. It is the schematic for demonstrating the electrophotographic process and electrophotographic apparatus of this invention. In the present invention, it is a diagram showing an example of a proximity charging mechanism in which a gap forming member is disposed on the charging member side. It is a diagram showing a transfer circuit capable of constant current control. It is a figure for demonstrating the process cartridge for electrophotographic apparatuses of this invention. 1 is a schematic view for explaining a tandem-type full-color electrophotographic apparatus of the present invention. FIG. It is a figure showing the layer structure of the electrophotographic photosensitive member used for this invention. It is a figure showing the layer structure of another electrophotographic photosensitive member used for this invention. It is a figure showing the XD spectrum of the dry powder of the water paste. 4 is a diagram illustrating an XD spectrum of titanyl phthalocyanine synthesized in Reference Synthesis Example 1. FIG. 4 is a diagram showing an XD spectrum of titanyl phthalocyanine synthesized in Comparative Synthesis Example 1. FIG. 6 is a diagram showing an XD spectrum of titanyl phthalocyanine synthesized in Comparative Synthesis Example 2. FIG. It is a figure showing the XD spectrum of the titanyl phthalocyanine used in the measurement example 1. It is a figure showing the XD spectrum of the titanyl phthalocyanine used in the measurement example 2. It is a TEM image of amorphous titanyl phthalocyanine. The scale bar in the figure is 0.2 μm. It is a TEM image of titanyl phthalocyanine after crystal conversion. The scale bar in the figure is 0.2 μm. It is a TEM image of a titanyl phthalocyanine crystal that has undergone crystal conversion in a short time. The scale bar in the figure is 0.2 μm. It is a figure which shows the state of the dispersion liquid when dispersion time is short. It is a figure which shows a state in case dispersion | distribution time is long. It is a figure which shows an average particle diameter and a particle size distribution about the dispersion liquid of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photoconductor 1C Photoconductor 1M Photoconductor 1Y Photoconductor 1K Photoconductor 2 Static elimination lamp 2C Charging member 2M Charging member 2Y Charging member 2K Charging member 3 Charging roller 3C Laser beam 3M Laser beam 3Y Laser beam 3K Laser beam 4C Developing member 4M Development Member 4Y Developing member 4K Developing member 5 Image exposing portion 5C Cleaning member 5M Cleaning member 5Y Cleaning member 5K Cleaning member 6 Developing unit 6C Image forming element 6M Image forming element 6Y Image forming element 6K Image forming element 7 Transfer paper 8 Paper feed roller 9 Registration roller 10 Transfer conveyor belt 11 Transfer bias roller 11C Transfer brush 11M Transfer brush 11Y Transfer brush 11K Transfer brush 12 Fixing device 13 Pre-cleaning charger 14 Fur brush 15 Cleaning brush 16 Developing roller 17 Transfer roller La 18 Separation claw 21 Gap forming member 22 Metal shaft 23 Image forming area 24 Non-image forming area 31 Conductive support 33 Intermediate layer 35 Charge generation layer 37 Charge transport layer 100 Photoconductor 101 Transfer conveyance belt 102 Drive roller 103 Driven roller 104 Bias roller 105 High voltage power supply (Power pack)
106 Current detection resistor

Claims (18)

An electrophotographic apparatus comprising at least a charging unit, an exposing unit, a developing unit, a transferring unit, and an electrophotographic photosensitive member, wherein a transfer current applied from the transferring unit to the electrophotographic photosensitive member is 65 μA or more. the electrophotographic photosensitive member, Ri Na by laminating at least a charge generation layer and a charge transport layer in this order on a conductive support, the charge generation layer is a layer containing titanyl phthalocyanine crystals, the titanyl phthalocyanine crystal As a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to CuKα characteristic X-ray (wavelength 1.542 mm), it has a maximum diffraction peak at at least 7.0 to 7.5 °, and half of the diffraction peak Amorphous titanyl phthalocyanine or low crystalline titanyl phthalocyanine having an average size of primary particles with a width of 1 ° or more and 0.1 μm or less is organically added in the presence of water. Crystal transformation is performed with a solvent, and titanyl phthalocyanine after crystal transformation is fractionated and filtered from the organic solvent before the average size of primary particles after crystal transformation grows larger than 0.30 μm. As a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to (wavelength 1.542 mm), it has a maximum diffraction peak at least 27.2 °, and further 9.4 °, 9.6 °, 24.0 °. And has a peak at 7.3 ° as the lowest angled diffraction peak, and has a peak between the 7.3 ° peak and the 9.4 ° peak. Further, it has a peak at 26.3 °, 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 °, and the primary particles. Crystals with an average size of less than 0.3 μm Electrophotographic apparatus, characterized in that. 2. The electrophotographic apparatus according to claim 1, wherein the electrophotographic apparatus controls a transfer current by constant current control. Current measuring means provided in a feedback mechanism that feeds back the bypass current that flows through the transfer member from the power supply to the power supply during transfer, and is measured by the output current from the power supply and the current measuring means. 2. The electrophotographic apparatus according to claim 1, wherein a transfer current flowing through the photosensitive member as a difference from the measured current is controlled. 4. The electrophotographic apparatus according to claim 1, wherein the charge transport layer contains at least a polycarbonate having a triarylamine structure in the main chain and / or 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 5 , wherein the protective layer contains an inorganic pigment or metal oxide having a specific resistance of 10 ¹⁰ Ω · cm or more. The electrophotographic apparatus according to claim 6 , wherein the metal oxide is any one of alumina, titanium oxide, and silica having a specific resistance of 10 ¹⁰ Ω · cm or more. The electrophotographic apparatus according to claim 7 , wherein the metal oxide is α-alumina having a specific resistance of 10 ¹⁰ Ω · cm or more. The electrophotographic apparatus according to claim 5, wherein the protective layer contains a polymer charge transport material. 10. The electrophotographic apparatus according to claim 1, wherein the charge transport layer of the photoreceptor is formed using a non-halogen solvent. The electrophotographic apparatus according to claim 10 , wherein at least one selected from cyclic ethers or aromatic hydrocarbons is used as the non-halogen solvent. The electrophotographic apparatus according to any one of claims 1 to 11, wherein the surface of the electroconductive support of the electrophotographic photosensitive member is anodized. 13. The electrophotographic apparatus according to claim 1 , wherein a plurality of image forming elements including at least a charging unit, an exposure unit, a developing unit, a transfer unit, and an electrophotographic photosensitive member are arranged. 14. The electrophotographic apparatus according to claim 1 , wherein a contact charging method is used as a charging unit of the electrophotographic apparatus. 14. The electrophotographic apparatus according to claim 1 , wherein a non-contact proximity arrangement method is used for the charging means of the electrophotographic apparatus. The electrophotographic apparatus according to claim 15 , wherein a gap between a charging member used for the charging unit and the photosensitive member is 200 μm or less. The electrophotographic apparatus according to claim 14, wherein an AC superimposed voltage is applied to charging means of the electrophotographic apparatus. The electrophotographic apparatus includes an apparatus main body in which a photosensitive member and at least one unit selected from a charging unit, an exposure unit, a developing unit, and a cleaning unit are integrated, and a detachable cartridge. The electrophotographic apparatus according to claim 1 .

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