JP2005338149A - Image forming apparatus and process cartridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a self-scanning LED array system image forming apparatus capable of achieving higher image quality, a higher speed and a longer operating life in a high level and in a well-balanced state. <P>SOLUTION: The image forming apparatus 100 has an electrophotographic photoreceptor 106 and an exposure device 110. In the image forming apparatus 100, an electrophotographic process including charge, exposure, development and transfer is carried out in order. The exposure device 110 has an LED array comprising a plurality of LEDs as an exposure light source and has configuration adopting a self-scanning LED array system by which a light beam is scanned on the electrophotographic photoreceptor according to image data to form an electrostatic latent image. The electrophotographic photoreceptor 106 has a conductive substrate 2 and a photosensitive layer 3 comprising a charge generating layer 5 and a charge transport layer 6 formed on the conductive substrate 2, wherein when the electrophotographic process is repeated by 400,000 cycles, an average wear rate of the photosensitive layer 3 is ≤15 nm per 1,000 cycles, and difference between maximum and minimum values of thickness in an image forming region of the photosensitive layer 3 after 400,000 cycles is ≤15% of an average thickness of the charge transport layer 6 before carrying out the electrophotographic process. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus and a process cartridge.

  In an image forming apparatus such as an electrophotographic printer, a copying machine, and a facsimile, an LED print head (LPH) using an LED as a light source is used as a print head.

In recent years, an image forming apparatus using a self-scanning LED (SLED) as an LED print head has been proposed (for example, see Patent Document 1). In this self-scanning LED, a thyristor structure is applied to a portion corresponding to a switch portion for selectively turning on and off a light emitting point. By applying this thyristor structure, the self-scanning LED is a light emitting light source array in which the switch portion can be arranged on the same chip as the light emitting point. In addition, the self-scanning LED can selectively emit light by using two signal lines at the on / off timing of the switch, so that the data line can be shared and the wiring can be simplified.
JP-A-2-263668

  However, when an electrophotographic process including exposure is performed at high speed using a self-scanning LED array, potential fluctuations and sensitivity fluctuations due to wear of the photosensitive layer of the electrophotographic photosensitive member are likely to occur, resulting in deterioration in image quality. The life of the apparatus will be reduced. In addition, when the image forming apparatus is downsized, the wear of the photosensitive layer is further promoted by the increase in the number of repetitions of the electrophotographic process due to the reduction in the diameter of the electrophotographic photosensitive member and the increase in load due to the use of a contact charger. End up.

  Although it is conceivable to increase the thickness of the photosensitive layer as a method for improving the life of the electrophotographic photosensitive member, such a method is practically applied to an image forming apparatus having an exposure device using a self-scanning LED array. Not right. Specifically, in the case of a self-scanning LED, the light emission time of each light emission point per dot is limited to one or less the number of light emission points per chip, and the light emission time is longer than that of an LED that can emit light continuously. Short and less light emission. For example, when 256 light emitting points are formed on one chip and light is emitted sequentially by self-scanning, the light emission time is 1/256 or less compared to an LED that can emit light continuously. As described above, when the amount of light on the electrophotographic photosensitive member is insufficient, the thickening of the photosensitive layer causes deterioration in image quality.

  Further, in the LED print head, the light emission amount of each LED is controlled by the lighting time in order to suppress the occurrence of vertical stripes in the halftone due to the light emission amount and profile difference between the light emitting elements. However, as described above, if the wear of the photosensitive layer is promoted due to an increase in the number of repetitions of the electrophotographic process, or an increase in load due to the use of a contact charger, there arises a problem that vertical stripes are generated on the transfer medium. .

  The present invention has been made in view of the above-described problems of the prior art, and is a self-scanning LED array type image forming apparatus and process capable of achieving high image quality, high speed, and long life in a balanced manner at a high level. An object is to provide a cartridge.

  In order to solve the above problems, an image forming apparatus of the present invention is an image forming apparatus that sequentially performs an electrophotographic process including charging, exposure, development, and transfer, and includes an electrophotographic photosensitive member and a plurality of LEDs. An exposure apparatus having a configuration that employs a self-scanning LED array system in which an array is used as an exposure light source and a light beam is scanned on an electrophotographic photosensitive member according to image data to form an electrostatic latent image; When the electrophotographic photosensitive member has a conductive substrate and a photosensitive layer comprising a charge generation layer and a charge transport layer formed on the conductive substrate, the average wear of the photosensitive layer when the electrophotographic process is repeated 400,000 cycles The rate is 15 nm or less per 1,000 cycles, and the difference between the maximum value and the minimum value in the image forming area of the photosensitive layer after 400,000 cycles is the electrophotographic profile. Characterized in that 15% or less the average thickness of the front of the charge transport layer to perform processes.

  According to the image forming apparatus of the present invention, by adopting the above-described configuration, it is possible to sufficiently prevent potential fluctuation and sensitivity fluctuation by controlling the wear amount and film thickness unevenness of the photosensitive layer when performing the electrophotographic process. Is possible. Therefore, the self-scanning LED array system that complements the characteristics of the self-scanning LED array that the variable light quantity is small and the control width is small according to the present invention, and that can achieve high image quality, high speed, and long life in a balanced manner at a high level. The image forming apparatus is realized.

  In the case of a self-scanning LED array, if the self-scanning LED array is used as an exposure light source, it is difficult to obtain a uniform amount of light for each LED. For this reason, in the conventional image forming apparatus, the amount of wear of the photosensitive layer in the electrophotographic process is assumed in advance, and an electrical correction process is performed to make the light quantity of each LED uniform. However, if the photosensitive layer wears at an abnormal speed or wears out unevenly without being uniformly worn at a presumed speed, a deviation occurs in the electrical correction processing of the light quantity of the LED, resulting in potential fluctuations. The image quality becomes insufficient due to sensitivity fluctuations. In this case, sufficient image quality cannot be obtained simply by hardening the photosensitive layer of the electrophotographic photosensitive member or reducing the wear amount of the photosensitive layer. On the other hand, in the image forming apparatus of the present invention, it is possible to prevent deviations in the electrical correction processing of the light amount of the LED by controlling the wear amount and film thickness unevenness of the photoreceptor.

  The image forming apparatus of the present invention preferably further includes a cleaning device for removing residual toner attached to the electrophotographic photosensitive member after transfer, and a lubricant supply device for supplying a lubricant to the electrophotographic photosensitive member. .

  By further providing the cleaning device and the lubricant supply device in this way, it becomes possible to suppress the abrasion of the photosensitive layer by the lubricant, and in combination with the above-described control of the abrasion amount and film thickness unevenness of the photosensitive layer, the image It is possible to achieve higher quality, higher speed and longer life of the forming apparatus.

  The image forming apparatus of the present invention is an image forming apparatus that sequentially performs an electrophotographic process including charging, exposure, development, transfer, and cleaning, and includes an electrophotographic photosensitive member and an LED array having a plurality of LEDs as an exposure light source. An exposure apparatus having a configuration employing a self-scanning LED array system in which an electrostatic latent image is formed by scanning a light beam on an electrophotographic photoreceptor according to image data, and an electrophotographic photoreceptor after transfer A cleaning device that removes residual toner attached to the electrophotographic photosensitive member, and a lubricant supply device that supplies a lubricant to the electrophotographic photosensitive member.

  According to the image forming apparatus of the present invention, by adopting the above configuration, the lubricity of the surface of the electrophotographic photosensitive member is enhanced by the supplied lubricant when the electrophotographic process is performed, and the surface is cleaned by the cleaning device. Since it is sufficiently cleaned, it is possible to sufficiently prevent potential fluctuation and sensitivity fluctuation by suppressing wear of the photosensitive layer. Therefore, the present invention complements the characteristics of the self-scanning LED array with a small variable light amount and a narrow control width, and can achieve high image quality, high speed and long life in a high level with a good balance. An image forming apparatus of the type is realized.

  Further, in the image forming apparatus of the present invention, the electrophotographic photosensitive member has a substantially cylindrical shape provided rotatably around the first axis, and the lubricant supply device moves the outer peripheral surface of the electrophotographic photosensitive member. It is preferable that it is disposed upstream of the cleaning device with respect to the direction.

  As a result, the surface of the electrophotographic photosensitive member can be cleaned while reducing the contact resistance of the cleaning device with respect to the electrophotographic photosensitive member, thereby more reliably preventing potential fluctuations and sensitivity fluctuations due to wear of the photosensitive layer. it can.

  Furthermore, in the image forming apparatus of the present invention, the lubricant supply device is provided so as to be rotatable about the second axis parallel to the first axis, and the rotating brush whose tip is in contact with the outer peripheral surface of the electrophotographic photosensitive member. And a support member that is swingably provided with a third axis parallel to the second axis as a fulcrum and supports the solid lubricant, and a moment from the support member toward the rotating brush around the third axis It is preferable that the solid lubricant is brought into contact with the rotating brush by the moment and the lubricant adhering to the rotating brush is supplied to the electrophotographic photosensitive member.

  In such a lubricant supply device, the lubricant attached to the rotating brush is applied to the electrophotographic photoreceptor by rotating the rotating brush in contact with the solid lubricant. Here, by generating a moment from the support member to the rotating brush around the third axis to bring the rotating brush and the solid lubricant into contact, the rotating brush and the solid lubricant are in contact with each other at a predetermined contact pressure. Further, irregular behavior such as the solid lubricant jumping up due to rotation of the rotating brush is prevented. Further, the support member that supports the solid lubricant is swingably provided with the third shaft as a fulcrum, and operations other than the circumferential direction of the third shaft are limited. The amount (bite-in amount) is kept substantially constant along the third axis direction. Therefore, by using such a lubricant supply device, it is possible to stably supply the lubricant over a long period of time while keeping the amount of the lubricant attached to the rotating brush and the amount supplied to the surface of the electrophotographic photosensitive member uniform. It becomes possible.

  Furthermore, the lubricant is preferably at least one selected from fatty acid metal salts and polytetrafluoroethylene. By using such a lubricant, potential fluctuations and sensitivity fluctuations due to wear of the photosensitive layer can be more reliably prevented.

  Furthermore, it is preferable that the amount of lubricant consumed when A4 size paper is used as the transfer medium is 2 to 15 μg per sheet. By setting the consumption amount of the lubricant to 2 to 15 μg, it becomes possible to maintain high image quality over a long period of time.

  The LED array preferably has a plurality of light emitting points arranged two-dimensionally. Thereby, higher image quality (higher resolution) and higher speed can be achieved at a higher level.

  Further, the linear velocity on the surface of the electrophotographic photosensitive member is preferably 100 mm / second or more. Thereby, even if the exposure amount per unit area of the electrophotographic photosensitive member is reduced, it is possible to realize high speed.

  Furthermore, it is preferable that the image resolution in the rotation direction of the electrophotographic photosensitive member is 1200 dpi (dots / inch) or more. Thereby, even if the effective light emission time of the LED is reduced and the exposure amount per unit area of the electrophotographic photosensitive member is reduced, high image quality (high resolution) can be achieved.

  The present invention further includes an electrophotographic photosensitive member and an LED array having a plurality of LEDs as an exposure light source, and scans a light beam on the electrophotographic photosensitive member according to image data to form an electrostatic latent image. An exposure apparatus having a configuration employing a type LED array system, and an electrophotographic photosensitive member having a conductive substrate and a photosensitive layer including a charge generation layer and a charge transport layer formed on the conductive substrate, When the electrophotographic process is repeated for 400,000 cycles, the average wear rate of the photosensitive layer is 15 nm or less per 1,000 cycles, and the maximum film thickness in the image forming area of the photosensitive layer after 400,000 cycles is The difference from the minimum value is 15% or less of the average film thickness of the charge transport layer before the electrophotographic process, An electrophotographic photosensitive member having a photosensitive layer formed on the conductive substrate and an LED array having a plurality of LEDs as an exposure light source, and scanning the light beam on the electrophotographic photosensitive member in accordance with image data. An exposure apparatus having a configuration employing a self-scanning LED array system for forming an electrostatic latent image, a cleaning apparatus for removing residual toner adhering to the electrophotographic photosensitive member after transfer, and a lubricant for the electrophotographic photosensitive member And a lubricant supply device for supplying the process cartridge.

  According to the process cartridge of the present invention, by adopting the above configuration, it is possible to easily control the abrasion of the photosensitive layer as in the image forming apparatus of the present invention by the process cartridge itself. Therefore, the potential fluctuation and sensitivity fluctuation of the electrophotographic photosensitive member are sufficiently prevented, and a self-scanning LED array type process cartridge capable of achieving high image quality, high speed and long life in a balanced manner is realized. Is done.

  According to the present invention, it is possible to provide a self-scanning LED array type image forming apparatus and process cartridge capable of achieving high image quality, high speed, and long life in a balanced manner at a high level.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings as the case may be. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and redundant description is omitted.

[First Embodiment of Image Forming Apparatus]
FIG. 1 is a schematic configuration diagram showing a preferred embodiment of an image forming apparatus of the present invention.
The image forming apparatus 100 is covered with a casing 102, and the upper surface of the image forming apparatus 100 also serves as the discharge tray unit 104. In the casing 102, an electrophotographic photosensitive member 106 is disposed at the center thereof. Around the electrophotographic photosensitive member 106, a charging device 108 for uniformly charging the surface of the electrophotographic photosensitive member 106 in a counterclockwise direction from slightly above to the right, a self-scanning LED (hereinafter referred to as an exposure light source). An exposure device 110 including a “SLED”), a developing device 116, an intermediate transfer belt 122, and a cleaning device 124 are disposed. Although not shown in detail in FIG. 1, the cleaning device 124 is integrated with the lubricant supply device. Details of the cleaning device 124 and the lubricant supply device will be described later with reference to FIG.

  The electrophotographic photoreceptor 106 has a photosensitive layer including a conductive substrate and a charge generation layer and a charge transport layer formed on the conductive substrate. Details of the electrophotographic photoreceptor 106 will be described later.

  The developing device 116 is equipped with a toner tank 112 for each color of cyan (C), magenta (M), yellow (Y), and black (K), and rotates to sequentially transfer the toner rolls 114 for each color to the electrophotographic photosensitive member. 106 is a rotary developing device that can be made to correspond to 106.

  The intermediate transfer belt 122 is wound around a plurality of rollers 120 and driven in the direction of arrow A in FIG. 1, and functions as a primary (intermediate) transfer member. When the toner image formed on the outer peripheral surface of the electrophotographic photosensitive member 106 is transferred to the intermediate transfer belt 122 by the developing device 116, the lubricant is supplied to the outer peripheral surface of the electrophotographic photosensitive member 106 by the lubricant supplying device. A region of the outer peripheral surface carrying the transferred toner image is cleaned by the cleaning device 124.

  A lower end portion of the intermediate transfer belt 122 is a part of a conveyance path of an image forming sheet (hereinafter simply referred to as “sheet”) 126, and the sheet 126 includes an intermediate transfer belt 122, a roller 118, and the lower end portion. It is nipped and conveyed between the two.

  A plurality of rollers 118 are arranged in the conveyance path of the sheet 126, and the uppermost sheet 126 stacked on the sheet feeding tray 128 is taken out by the sheet feeding device 130, and comes into contact with the lower end portion of the intermediate transfer member 124. The sheet is conveyed and sent out to the discharge tray section 104 via the fixing section 132.

  A density sensor 134 is provided at a position facing a part of the conveyance path of the intermediate transfer belt 122 so as to detect the density of, for example, a test patch (color and density sample).

  Next, the exposure apparatus 110 will be described in detail. The exposure apparatus 110 is composed of a light source array using SLED. FIG. 2 is a perspective view showing the appearance of the light source array. The light source array 140 is configured by further arranging a plurality of LED arrays (light emitting element arrays) 152 in which a plurality of chip-shaped LEDs 150 are arranged along the axial direction of the electrophotographic photosensitive member 106 in series. The light emitting points of the LEDs 150 are preferably arranged in a two-dimensional manner (for example, a staggered pattern). The light source array 140 is lighting-controlled by a drive circuit 156 (see FIG. 3) controlled within the same casing 154, and scans a light beam according to image data.

  FIG. 3 shows details of the drive circuit 156 of the light source array 140. The drive circuit 156 is basically a combination of a single drive circuit shown in FIG. Here, the detailed description of the thyristor 10 and the like is omitted.

  As a trigger for turning on the SLED, the voltage VS is applied to the point P1 (the number following the point P indicates the order of the plurality of LEDs arranged) via the resistor 158. All the points P (1 to N (N is a positive integer)) including the point P1 are connected to the base line 161 via the resistor 160, respectively. The base line 161 maintains a predetermined voltage in the first stage, and is set to a potential (Φga) that decreases by a predetermined potential (Vf) as it goes to each stage.

  Further, the point P (1 to N) is connected to the anode side of the LED 150. The cathode side of the LED 150 is connected to a gradation signal line 163 described later.

  Here, as shown in FIG. 4, the driving circuit of Φga is driven at a constant current upon receiving a light quantity instruction value from an APC (auto power control) 162 based on a detection signal from the density sensor 134. (Constant current drive circuit). That is, the light quantity instruction value is converted into an analog value by the DA converter 164 and connected to the negative side input terminal of the first comparator 168 via the resistor 166. The positive side input terminal of the first comparator 168 is grounded (GND). The output terminal of the first comparator 168 and the negative input terminal are connected via a resistor 170. As a result, the output of the first comparator 168 changes depending on the light quantity instruction value and becomes a predetermined voltage.

  Here, this output voltage is connected to the positive input terminal of the second comparator 172, the negative input terminal is connected to the reference voltage source VSS via the resistor 174, and the output terminal of the second comparator 172 is further connected. Is connected to the MOS transistor 176, a constant current flows through the MOS transistor 176.

  In FIG. 4, the driving circuit of Φga is the constant current driving circuit 178, but a constant voltage driving circuit 180 as shown in FIG. 5 may be used. Since the circuit configuration only needs to use the output of the first comparator 168 in FIG. 4, the same reference numerals are given and description of the configuration is omitted.

  As shown in FIG. 3, the emitter of the odd-numbered transistor Q2 is connected to the first control line (V1) 182, and the emitter of the even-numbered transistor Q2 is connected to the second control line (V2) 184. Yes. The point P (1 to N) of each stage is connected to one end of the LED 150, and the other end of the LED 150 is connected to a gradation signal line 163 that outputs a pulse wave that is a gradation signal of each stage. . When the gradation signal line 163 is at a low level (L), the LED is lit if the point P (1 to N) is at a predetermined potential.

  FIG. 6 shows a circuit 200 for generating a pulse waveform sent to the gradation signal line 163. The gradation signal (12 bits) output from the image processing unit 202 is input to the integrator 204. For example, the image processing unit 202 converts images in various formats sent from a recording medium, a communication line, or the like into a format corresponding to the image forming apparatus 100 of the present embodiment. Correction data (4 bits) held in the correction data holding unit 206 is also input to the accumulator 204, and unevenness of the light emission point of each LED 150 is corrected.

  The corrected gradation signal with the correction data added by the integrator is converted into an analog signal by the DA converter 208 (density signal), and the plus of the comparator 210 is input to the input terminal.

  On the other hand, branch lines 182A and 184A are connected to the control signal lines V1 (Φ1) and V2 (Φ2) output from the timing generator 212, respectively, and these branch lines 182A and 184A are input to the OR circuit 186. For this reason, the output of the OR circuit 186 is active when either one of V1 and V2 is active (here, low level). In synchronization with this active time, the triangular wave generation circuit 188 generates a triangular wave and inputs it to the negative side input terminal of the comparator 210.

  This operation is shown in the time chart of FIG. That is, a triangular wave is formed according to a signal obtained by ORing V1 (Φ1) and V2 (Φ2). At this time, a space a is generated between the triangular waves, and this becomes an interval for sequentially lighting one by one at the lighting timing of the odd-numbered LED and the even-numbered LED.

  By superimposing the density signal on this triangular wave, the range of the level higher than the density signal in the triangular wave becomes the actual lighting time, and a pulse waveform to be sent to the gradation signal line 163 can be generated.

  FIG. 8 is an operation timing chart of the LED drive circuit of FIG. 3, and FIG. 9 is a characteristic diagram showing the LED light emission state of the LED drive circuit of FIG. Here, the details are omitted.

  Note that the image forming apparatus 100 may directly transfer the toner image on the electrophotographic photosensitive member 106 to the sheet 126. After the toner image on the electrophotographic photosensitive member 106 is transferred to the intermediate transfer member, the image forming apparatus 100 may further include: An intermediate transfer method of transferring to a transfer medium may be used. As the intermediate transfer member, the belt-shaped intermediate transfer belt 122 is used as the intermediate transfer member in the image forming apparatus 100 shown in FIG. 1, but a drum-shaped intermediate transfer member may be used.

  Next, the electrophotographic photoreceptor 106 will be described in detail. FIG. 11 is a schematic cross-sectional view showing an example of an electrophotographic photosensitive member. The electrophotographic photosensitive member 106 has a function-separated type photosensitive layer 3 in which an undercoat layer 4, a charge generation layer 5, a charge transport layer 6, and a protective layer 7 are sequentially laminated on a conductive support 2.

  The material of the conductive substrate 2 includes metals such as aluminum, nickel, chromium, and stainless steel; aluminum, titanium, nickel, chromium, stainless steel, gold, vanadium, tin oxide, indium oxide, ITO, etc. on a substrate such as plastic Or a paper coated with or impregnated with a conductivity-imparting agent, a plastic film, or the like. Although the electrophotographic photosensitive member 106 in FIG. 1 has a drum shape, it may have a sheet shape, a plate shape, or the like.

  When a metal pipe substrate is used as the conductive substrate 2, the surface of the substrate may be a raw tube, and mirror cutting, etching, anodizing, rough cutting, centerless grinding, sand blasting, wet honing, coloring treatment in advance. Such processing may be performed. By roughening the surface of the substrate, it is possible to prevent grain-like density spots due to interference light in the electrophotographic photosensitive member 106 that may occur when a coherent light source is used.

  The undercoat layer 4 prevents the injection of charges from the conductive substrate 2 to the photosensitive layer 3 when the photosensitive layer 3 is charged, and allows the photosensitive layer 3 to be adhered and held integrally with the conductive substrate 2. It has an action as an adhesive layer, or an antireflection effect of light of the conductive substrate 2 depending on circumstances.

  Materials for the undercoat layer 4 include acetal resins such as polyvinyl butyral, polyvinyl alcohol resin, casein, polyamide resin, cellulose resin, gelatin, polyurethane resin, polyester resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, and polyvinyl acetate resin. And polymer resin compounds such as vinyl chloride-vinyl acetate-maleic anhydride resin, silicone resin, silicone-alkyd resin, phenol-formaldehyde resin, melamine resin. Further, a zirconium chelate compound, a titanium chelate compound, an aluminum chelate compound, a titanium alkoxide compound, an organic titanium compound, a silane coupling agent, or the like may be used. In addition, a charge transporting resin having a charge transporting group, a conductive resin such as polyaniline, or the like can be used. These compounds can be used alone or as a mixture or polycondensate of two or more. Among these, resins that are insoluble in the upper layer coating solvent are preferably used, and phenol resins, phenol-formaldehyde resins, melamine resins, urethane resins, epoxy resins, and the like are particularly preferably used. Furthermore, zirconium chelate compounds and silane coupling agents are excellent in performance, such as low residual potential, little potential change due to environment, and little potential change due to repeated use.

  Examples of silane coupling agents include vinyltrimethoxysilane, γ-methacryloxypropyl-tris (6-methoxyethoxy) silane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, and γ-glycidoxypropyltrimethoxy. Silane, vinyltriacetoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) -γ -Aminopropylmethylmethoxysilane, N, N-bis (β-hydroxyethyl) -γ-aminopropyltriethoxysilane, γ-chloropropyltrimethoxysilane and the like. Among these, vinyltriethoxysilane, vinyltris (2-methoxyethoxysilane), 3-methacryloxypropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxy Silane, N-2- (aminoethyl) 3-aminopropyltrimethoxysilane, N-2- (aminoethyl) 3-aminopropylmethyldimethoxysilane, 3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyl Silane coupling agents such as trimethoxysilane, 3-mercaptopropyltrimethoxysilane, and 3-chloropropyltrimethoxysilane are preferred.

  Zirconium chelate compounds include: zirconium butoxide, zirconium zirconium acetoacetate, zirconium triethanolamine, acetylacetonate zirconium butoxide, ethyl acetoacetate butoxide, zirconium acetate, zirconium oxalate, zirconium lactate, zirconium phosphonate, zirconium octoate, naphthenic acid Zirconium, zirconium laurate, zirconium stearate, zirconium isostearate, methacrylate zirconium butoxide, stearate zirconium butoxide, isostearate zirconium butoxide and the like.

  Titanium chelate compounds include tetraisopropyl titanate, tetranormal butyl titanate, butyl titanate dimer, tetra (2-ethylhexyl) titanate, titanium acetylacetonate, polytitanium acetylacetonate, titanium octylene glycolate, titanium lactate ammonium salt, titanium Examples include lactate, titanium lactate ethyl ester, titanium triethanolamate, and polyhydroxytitanium stearate.

  Examples of the aluminum chelate compound include aluminum isopropylate, monobutoxy aluminum diisopropylate, aluminum butyrate, diethyl acetoacetate, aluminum diisopropylate, and aluminum tris (ethyl acetoacetate).

  The undercoat layer 4 can contain a conductive substance for improving the photoreceptor characteristics. Examples of such a conductive substance include metal oxides such as titanium oxide, zinc oxide, and tin oxide. Any known substance can be used as long as desired photoreceptor characteristics can be obtained.

  The metal oxide used for the undercoat layer 4 can be subjected to a surface treatment. By performing the surface treatment, resistance value control, dispersibility control, and improvement in photoreceptor characteristics can be achieved. As the surface treatment agent, known materials such as a zirconium chelate compound, a titanium chelate compound, an aluminum chelate compound, a titanium alkoxide compound, an organic titanium compound, and a silane coupling agent can be used. These compounds can be used alone or as a mixture or polycondensate of two or more compounds. Among them, the silane coupling agent is excellent in performance such as a low residual potential, a small potential change due to the environment, a small potential change due to repeated use, and excellent image quality characteristics. In addition, as a silane coupling agent, a zirconium chelate compound, a titanium chelate compound, and an aluminum chelate compound, the same substance as the example mentioned above is mentioned.

  As the surface treatment method, any known method can be used, but a dry method or a wet method can be used. When surface treatment is performed by a dry method, a silane coupling agent dissolved directly or in an organic solvent is dropped and sprayed with dry air or nitrogen gas while stirring the metal oxide fine particles with a mixer having a large shearing force. Can be processed uniformly. The addition or spraying is preferably performed at a temperature below the boiling point of the solvent. Spraying at a temperature equal to or higher than the boiling point of the solvent is not preferred because it causes the solvent to evaporate before being stirred uniformly, causing the silane coupling agent to locally accumulate and making uniform processing difficult. After addition or spraying, baking can be performed at 100 ° C. or higher. Baking can be carried out in an arbitrary range as long as the temperature and time allow the desired electrophotographic characteristics to be obtained. As a wet method, the metal oxide fine particles are dispersed in a solvent using stirring, ultrasonic waves, a sand mill, an attritor, a ball mill, etc., and a silane coupling agent solution is added and stirred or dispersed, and then the solvent is removed. Uniformly processed. The solvent removal method is distilled off by distillation. The removal method by filtration is not preferable because unreacted silane coupling agent tends to flow out, and the amount of silane coupling agent for obtaining desired characteristics is difficult to control. After removing the solvent, baking can be performed at 100 ° C. or higher. Baking can be carried out in an arbitrary range as long as the temperature and time allow the desired electrophotographic characteristics to be obtained. In the wet method, as a method for removing the metal oxide fine particle-containing water, a method of removing with stirring and heating in a solvent used for surface treatment, or a method of removing by azeotropic distillation with a solvent can be used.

  The amount of the silane coupling agent relative to the metal oxide fine particles in the undercoat layer 4 can be any amount as long as desired electrophotographic characteristics can be obtained.

  The ratio between the gold image oxide fine particles and the resin used in the undercoat layer 4 can be arbitrarily set as long as the desired electrophotographic characteristics can be obtained.

  Various organic or inorganic fine powders can be mixed in the undercoat layer 4 for the purpose of improving light scattering properties. In particular, white pigments such as titanium oxide, zinc oxide, zinc sulfide, lead white, and lithopone, inorganic pigments such as alumina, calcium carbonate, and barium sulfate, PTFE resin particles, benzoguanamine resin particles, and styrene resin particles are effective. It is. The added fine powder has a particle size of 0.01 to 2 μm. The fine powder is added as necessary, but when added, it is preferably 10 to 80% by mass, more preferably 30 to 70% by mass, based on the solid content of the undercoat layer 4 Is done.

  Various additives can be used in the coating liquid for forming the undercoat layer in order to improve electrical characteristics, environmental stability, and image quality. Additives include quinone compounds such as chloranil, bromoanil and anthraquinone, tetracyanoquinodimethane compounds, fluorenones such as 2,4,7-trinitrofluorenone and 2,4,5,7-tetranitro-9-fluorenone Compounds, 2- (4-biphenyl) -5- (4-t-butylphenyl) -1,3,4-oxadiazole and 2,5-bis (4-naphthyl) -1,3,4-oxadi Azoles, oxadiazole compounds such as 2,5-bis (4-diethylaminophenyl) -1,3,4 oxadiazole, xanthone compounds, thiophene compounds, 3,3 ′, 5,5 ′ tetra-t- It is also effective to contain an electron transporting substance such as a diphenoquinone compound such as butyldiphenoquinone, an electron transporting pigment such as a polycyclic condensation system or an azo group.

  In the formation of the undercoat layer coating liquid, when the fine powder such as the conductive material or the light scattering material as described above is mixed, the fine powder is added to the solution in which the resin component is dissolved and the dispersion treatment is performed. As a method for dispersing the fine powder in the resin, methods such as a roll mill, a ball mill, a vibrating ball mill, an attritor, a sand mill, a colloid mill, and a paint shaker can be used. Further, as the coating method used when the undercoat layer 4 is provided, conventional methods such as a blade coating method, a wire bar coating method, a spray coating method, a dip coating method, a bead coating method, an air knife coating method, and a curtain coating method are used. Can be used.

  The film thickness of the undercoat layer 4 is preferably 0.01 to 50 μm, more preferably 0.05 to 30 μm.

  Next, the charge generation layer 5 will be described. The charge generation layer 5 includes a charge generation material and a binder resin. The binder resin can be selected from a wide range of insulating resins, and can also be selected from organic photoconductive polymers such as poly-N-vinylcarbazole, polyvinylanthracene, polyvinylpyrene, and polysilane. Preferred binder resins include polyvinyl butyral resin, polyarylate resin (polycondensate of bisphenol A and phthalic acid, etc.), polycarbonate resin, polyester resin, phenoxy resin, vinyl chloride-vinyl acetate copolymer, polyamide resin, acrylic resin. Insulating resins such as polyacrylamide resin, polyvinyl pyridine resin, cellulose resin, urethane resin, epoxy resin, casein, polyvinyl alcohol resin, polyvinyl pyrrolidone resin can be mentioned, but are not limited thereto. These binder resins can be used alone or in combination of two or more.

  The charge generation material is not particularly limited, but metal and metal-free phthalocyanine pigments are preferable, and hydroxygallium phthalocyanine, chlorogallium phthalocyanine, dichlorotin phthalocyanine, and titanyl phthalocyanine having specific crystals are particularly preferable.

  The mixing ratio of the charge generation material and the binder resin (mass ratio) is preferably in the range of 10: 1 to 1:10. In addition, as a method for dispersing these, a usual method such as a ball mill dispersion method, an attritor dispersion method, a sand mill dispersion method, or the like can be used. . In the present embodiment, it is confirmed that the crystal form is not changed from that before dispersion in any of the above dispersion methods. Further, in this dispersion, it is effective that the particles have a particle size of 0.5 μm or less, preferably 0.3 μm or less, more preferably 0.15 μm or less. Moreover, as a solvent used for these dispersions, methanol, ethanol, n-propanol, n-butanol, benzyl alcohol, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, n-butyl acetate, dioxane, Usual organic solvents such as tetrahydrofuran, methylene chloride, chloroform, chlorobenzene and toluene can be used alone or in admixture of two or more. Further, the film thickness of the charge generation layer 5 in the present embodiment is generally 0.1 to 5 μm, preferably 0.2 to 2.0 μm. In addition, as a coating method used when the charge generation layer 5 is provided, a normal method such as a blade coating method, a Meyer bar coating method, a spray coating method, a dip coating method, a bead coating method, an air knife coating method, or a curtain coating method is used. Can be used. Further, a pigment surface-treated with a silane coupling agent may be used for the purpose of increasing the dispersion stability of the pigment, light sensitivity, or stabilizing the electrical characteristics. May be added.

  Next, the charge transport layer 6 will be described. The charge transport layer 6 is formed containing a charge transport material and a binder resin, or is formed containing a polymer charge transport material.

  Examples of charge transport materials include quinone compounds such as p-benzoquinone, chloranil, bromanyl, anthraquinone, tetracyanoquinodimethane compounds, fluorenone compounds such as 2,4,7-trinitrofluorenone, xanthone compounds, benzophenone compounds Electron transporting compounds such as cyanovinyl compounds and ethylene compounds, triarylamine compounds, benzidine compounds, arylalkane compounds, aryl-substituted ethylene compounds, stilbene compounds, anthracene compounds, hydrazone compounds, etc. Examples thereof include pore transporting compounds. These charge transport materials can be used alone or in combination of two or more, but are not limited thereto.

  As the binder resin used for forming the charge transport layer 6, polycarbonate resin, polyester resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, polyvinylidene chloride resin, polystyrene resin, polyvinyl acetate resin, styrene-butadiene copolymer, Vinylidene chloride-acrylonitrile copolymer, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer, silicone resin, silicon-alkyd resin, phenol-formaldehyde resin, styrene-alkyd resin, poly Polymeric charge transport materials such as -N-vinylcarbazole, polysilane, and polyester-based polymer charge transport materials disclosed in JP-A-8-176293 and JP-A-8-208820 can also be used. The film thickness of the charge transport layer 6 according to this embodiment is generally 5 to 50 μm, preferably 15 to 22 μm. As a coating method, a normal method such as a blade coating method, a Meyer bar coating method, a spray coating method, a dip coating method, a bead coating method, an air knife coating method, or a curtain coating method can be used. Furthermore, as a solvent used when providing a charge transport layer, aromatic hydrocarbons such as benzene, toluene, xylene and chlorobenzene, ketones such as acetone and 2-butanone, and halogenation such as methylene chloride, chloroform and ethylene chloride Ordinary organic solvents such as aliphatic hydrocarbons, cyclic or linear ethers such as tetrahydrofuran and ethyl ether can be used alone or in admixture of two or more. Usually, the charge transport layer 6 is formed by mixing these materials and drying the coating liquid with hot air.

  Additives such as antioxidants, light stabilizers, and heat stabilizers in the photosensitive layer for the purpose of preventing deterioration of the photoreceptor 106 due to ozone, oxidizing gas, or light / heat generated in the image forming apparatus 100. Can be added. For example, examples of the antioxidant include hindered phenol, hindered amine, paraphenylenediamine, arylalkane, hydroquinone, spirochroman, spiroidanone and derivatives thereof, organic sulfur compounds, and organic phosphorus compounds. Examples of light stabilizers include derivatives such as benzophenone, benzoazole, dithiocarbamate, and tetramethylpipen.

  Next, the protective layer 7 will be described. The protective layer 7 has a function of preventing the chemical change of the charge transport layer 6 and the like during charging, and further improving the mechanical strength of the photosensitive layer 3. For example, the protective layer 7 is appropriately bonded with a conductive material. It is configured to be contained in the resin.

  Examples of the conductive material used for forming the protective layer 7 include metallocene compounds such as N, N′-dimethylferrocene, N, N′-diphenyl-N, N′-bis (3-methylphenyl)-[1,1 ′. -Biphenyl] -4,4′-diamine and other aromatic amine compounds, molybdenum oxide, tungsten oxide, antimony oxide, tin oxide, titanium oxide, indium oxide, tin oxide and antimony oxide, or a solid solution carrier of these A mixture, a mixture of these metal oxides in a single particle, or a coating of these may be mentioned, but the invention is not limited to these.

  As the binder resin used for forming the protective layer 125, polyamide resin, polyvinyl acetal resin, polyurethane resin, polyester resin, epoxy resin, polyketone resin, polycarbonate resin, polyvinyl ketone resin, polystyrene resin, polyacrylamide resin, polyimide resin, polyamide Examples thereof include imide resins, and these can be used after being crosslinked. Furthermore, a siloxane-based resin having a charge transporting property and having a crosslinked structure can be used as the protective layer. In the case of a cured siloxane resin film containing a charge transporting compound, any known material can be used as the charge transporting compound. For example, JP-A-10-95787, JP-A-10-251277, Examples thereof include, but are not limited to, compounds disclosed in JP-A-11-32716, JP-A-11-38656, and JP-A-11-236391.

  In the electrophotographic photoreceptor 106 according to this embodiment, when the electrophotographic process is repeated 400,000 cycles, the average wear rate of the photosensitive layer 3 is 15 nm or less, preferably 12 nm or less, more preferably 9 nm or less per 1,000 cycles. It is. Further, the difference between the maximum value and the minimum value of the film thickness in the image forming region of the photosensitive layer 3 is 15% or less, preferably 12% or less of the average film thickness of the charge transport layer 6 before performing the electrophotographic process. More preferably, it is 9% or less. Thereby, higher image quality, higher speed, and longer life can be achieved at a higher level.

  The linear velocity on the surface of the electrophotographic photosensitive member 106 is preferably 100 mm / second or more, more preferably 120 mm / second or more, and still more preferably 150 mm / second or more, from the viewpoint of increasing the speed. Further, the image resolution in the rotation direction of the electrophotographic photosensitive member 106 is preferably 1200 dpi or more, more preferably 1800 dpi or more, and further preferably 2400 dpi or more, from the viewpoint of high resolution and high image quality.

  Further, the image forming apparatus 100 according to the present embodiment can include a lubricating oil supply device and a cleaning device 124 as necessary. By providing the lubricating oil supply device and the cleaning device 124, wear of the electrophotographic photosensitive member 106 can be suppressed. In addition, the electrophotographic photosensitive member is selected by selecting the type of constituent material of the photosensitive layer 3, the amount of lubricant supplied from a lubricant supplying device, which will be described later, the contact pressure between the cleaning device 124 and the electrophotographic photosensitive member 106, and the like. The mechanical or chemical strength of 106 can be further increased.

  Next, the lubricating oil supply device will be described in detail. FIG. 12 is an exploded perspective view showing a main part of the lubricant supply device. As illustrated, the lubricant supply device 200 includes a rotating brush 212, a support member 216, a torsion spring coil 217, and two bearing members 218.

  The rotating brush 212 is provided so as to be rotatable about a shaft portion 212 a (second axis) parallel to the rotating shaft (first axis) of the electrophotographic photosensitive member 106, and the tip of the brush is the end of the electrophotographic photosensitive member 106. It arrange | positions so that an outer peripheral surface may be contacted. The rotating brush 212 is rotatably supported by passing both ends of the shaft portion 212a through the shaft hole 218a of the bearing member 218. The rotation direction of the rotary brush 212 is preferably the same direction at the contact position with the electrophotographic photosensitive member 106. The rotational speed of the rotary brush 212 may be set so that the moving speed of the tip of the rotating brush 212 is higher than the moving speed of the outer peripheral surface of the electrophotographic photosensitive member 106 at the position of contact with the electrophotographic photosensitive member 106. preferable.

  The support member 216 includes a plate-like support portion 216a and a shaft portion 216b provided at an end portion of the support portion 216a on the rear side (the opposite side to the photoconductor 106). The solid lubricant 214 is attached to the surface of the support portion 216a on the rotating brush 212 side. As the solid lubricant 214, fatty acid metal salts and polytetrafluoroethylene are preferably used. Further, the shaft portion 216b functions as a third shaft parallel to the shaft portion 2a by having both ends thereof passed through the shaft hole 218b of the bearing member 218, and the support member 216 is swingable with the shaft portion 216b as a fulcrum. Supported.

  Around the shaft portion 216b, a moment from the support member 216 toward the rotating brush 212 is generated around the shaft portion 216b due to the weight of the support portion 216a and the gravity of the solid lubricant 214. Due to this moment, the solid lubricant 214 comes into contact with the rotating brush 212 at a predetermined pressure. Since the strength of the pressure increases as the weight of the support portion 216a and the weight of the solid lubricant 214 increases, the contact pressure of the solid lubricant 214 with respect to the rotating brush 212 can be set by appropriately setting these values. Further, the moment can be increased by attaching a weight on the surface of the support portion 216a opposite to the solid lubricant 214.

  Further, the torsion spring coil 217 is for increasing the contact pressure of the solid lubricant 214 with respect to the rotary brush 212, and is disposed in contact with the surface of the support portion 216a opposite to the solid lubricant 214. Note that the torsion spring coil 217 may not be used when a sufficient moment can be generated by the weight of the support portion 216a and the gravity of the solid lubricant 214.

In the lubricant supply device 200 having the above configuration, the lubricant attached to the rotary brush 212 is applied to the electrophotographic photosensitive member 106 by rotating the rotary brush 212 in contact with the solid lubricant 214. The amount of consumption of the solid lubricant 214 is not particularly limited as long as sufficient lubricity is imparted to the outer peripheral surface of the electrophotographic photosensitive member 106. For example, when A4 size paper is used as the transfer medium, the solid lubricant The consumption amount of 214 is preferably ^{2 to} 15 μg per sheet (7.6 to 57 ng / cm ² per unit area).

  Further, when the lubricant is supplied by the lubricant supply device 200, the support member 216 is restricted from moving in a direction other than the circumferential direction of the shaft portion 216b, and therefore, the nip amount (biting amount) of the solid lubricant 214 with respect to the rotating brush 212. Is substantially constant in the direction along the shaft portion 216b. Therefore, the amount of solid lubricant 214 consumed, that is, the amount of solid lubricant 214 attached to the rotating brush 212 is uniform in the axial direction, and the amount of lubricant applied to the outer peripheral surface of the electrophotographic photosensitive member 106 is also uniform. It becomes. Accordingly, a high level of lubricity can be stably imparted to the outer peripheral surface of the electrophotographic photosensitive member 106 over a long period of time, and potential fluctuations and sensitivity fluctuations due to wear of the electrophotographic photosensitive member 106 (photosensitive layer) can be sufficiently prevented. be able to. Further, such lubricity makes it difficult for the subsequent cleaning blade to be worn or chipped, so that the cleaning performance can be maintained at a high level for a long period of time.

  Further, since the support member 216 that supports the solid lubricant 214 generates a moment around the shaft portion 216b, the solid lubricant 214 can be brought into contact with the rotary brush 212 with a predetermined contact pressure due to the moment. Since random movement such as the splashing of the solid lubricant 214 due to the rotation of the rotating brush 212 can be suppressed, the solid lubricant 214 can be stably supplied over a long period of time with a constant nip amount. Therefore, even when the supply amount of the solid lubricant 214 is increased, stable supply of the lubricant can be effectively performed.

  The toner attached to the rotating brush 212 is removed by a flicker (not shown) and collected by a toner transport auger (not shown).

  Next, the cleaning device 124 will be described in detail. FIG. 13 is a schematic configuration diagram illustrating an example of a cleaning device. The cleaning device 124 is for removing residual toner adhering to the surface of the electrophotographic photosensitive member 106 after the transfer process, and the electrophotographic photosensitive member 106 thus cleaned is repeatedly used for the electrophotographic process. .

  The cleaning device 124 according to the present embodiment is integrated with the lubricant supply device 200, except that the cleaning blade 222 is attached to the downstream side of the rotating brush 212 at the front portion of the housing 50, as shown in FIG. The same configuration as the lubricating oil supply device shown in FIG. In addition, the cleaning device 124 applies a solid lubricant 214 to the electrophotographic photosensitive member 106 by the rotating brush 212 to reduce the contact resistance of the cleaning blade 222. Then, the toner adhering to the rotating brush 212 is removed by a flicker (not shown) and collected by a toner transport auger (not shown). As the cleaning device 124, in addition to a cleaning blade, brush cleaning, roll cleaning, and the like can be used. Among these, it is preferable to use a cleaning blade. Examples of the material for the cleaning blade include urethane rubber, neoprene rubber, and silicone rubber.

  As described above, in this embodiment, by combining the exposure apparatus 110 including the SLED and the electrophotographic photosensitive member 106, it becomes easy to control the wear amount and film thickness unevenness of the photosensitive layer 3. In addition, by further combining the lubricant supply device 200 and the cleaning device 124, the lubricity of the outer peripheral surface of the electrophotographic photosensitive member 106 is enhanced by the supplied lubricant during the electrophotographic process, and the cleaning device 124. The surface is sufficiently cleaned. Thereby, abrasion of the photosensitive layer 3 can be suppressed and potential fluctuation and sensitivity fluctuation can be sufficiently prevented. Therefore, according to the present invention, the characteristics of the self-scanning LED having a small variable light amount and a narrow control range are complemented, and an image forming apparatus capable of achieving high image quality, high speed, and long life at a high level in a balanced manner is realized. .

  The present invention is not limited to the above embodiment. For example, the electrophotographic photoreceptor 106 is not limited to the one having the laminated structure shown in FIG. 11, and the undercoat layer 4 and the protective layer 7 are provided when sufficient electrophotographic characteristics are obtained. It does not have to be.

  12 includes a support member 216 in which the support portion 216a and the shaft portion 216b are integrated. The shaft corresponding to the third shaft is fixed to the bearing member 218 and supported. By providing a through-hole in the member, the support member can be swingable independently of the shaft.

  In the image forming apparatus 100 shown in FIG. 1, the lubricant supply device and the cleaning device 124 are integrated. However, the lubricant supply device and the cleaning supply device may be provided separately.

[Second Embodiment of Image Forming Apparatus]
Next, a second embodiment of the image forming apparatus will be described. In addition, the same code | symbol is attached | subjected about the component same or equivalent to 1st Embodiment, and the overlapping description is abbreviate | omitted.

  The image forming apparatus according to the present embodiment has the same configuration as that of the image forming apparatus shown in FIG. 1 and is different in that the lubricant supply device and the cleaning device 124 are essential elements. In other words, the image forming apparatus 100 according to the present embodiment includes the electrophotographic photosensitive member 106, the exposure device 110, the lubricant supply device, and the cleaning device 124. The configurations and arrangements of the exposure apparatus 110, the lubricating oil supply apparatus, and the cleaning apparatus 124 are as described in the first embodiment.

  The electrophotographic photosensitive member 106 is not limited to the one having the function-separated type photosensitive layer 3 as shown in FIG. 11, and is a single-layer type photosensitive material including a charge generation material and a charge transport material in the same layer. It may have the layer 3. Further, when sufficient electrophotographic characteristics are obtained, the undercoat layer 4 and the protective layer 7 may not be provided.

  Furthermore, also in the electrophotographic photoreceptor 106 according to the present embodiment, when the electrophotographic process is repeated for 400,000 cycles, the average wear rate of the photosensitive layer 3 is preferably 15 nm or less per 1,000 cycles, and more preferably 12 nm or less. 9 nm or less is more preferable. Further, the difference between the maximum value and the minimum value of the film thickness in the image forming area of the photosensitive layer 3 is preferably 15% or less of the average film thickness of the charge transport layer 6 before the electrophotographic process, and 12% or less. More preferred is 9% or less. Thereby, higher image quality, higher speed, and longer life can be achieved at a higher level.

  The linear velocity on the surface of the electrophotographic photosensitive member 106 is preferably 100 mm / second or more, more preferably 120 mm / second or more, and still more preferably 150 mm / second or more, from the viewpoint of increasing the speed. Further, the image resolution in the rotation direction of the electrophotographic photosensitive member 106 is preferably 1200 dpi or more, more preferably 1800 dpi or more, and further preferably 2400 dpi or more, from the viewpoint of high resolution and high image quality.

  As described above, in this embodiment, by combining the exposure apparatus 110 including the SLED, the lubricant supply apparatus 200, and the cleaning apparatus 124, the outer peripheral surface of the electrophotographic photosensitive member 106 is supplied by the supplied lubricant when performing the electrophotographic process. In addition, the surface of the surface is sufficiently cleaned by the cleaning device 124, so that wear of the photosensitive layer 3 can be suppressed and potential fluctuation and sensitivity fluctuation can be sufficiently prevented. Therefore, according to the present invention, the characteristics of the self-scanning LED having a small variable light amount and a narrow control width are complemented, and an image forming apparatus capable of achieving high image quality, high speed and long life in a balanced and high level is realized. .

[First Embodiment of Process Cartridge]
Next, the process cartridge will be described. The process cartridge according to the present embodiment includes an electrophotographic photosensitive member and an exposure device.

  FIG. 13 is a schematic view showing a preferred embodiment of a process cartridge. As shown in FIG. 13, the process cartridge 300 includes a casing 311, and the electrophotographic photosensitive member 106 is disposed inside the casing 311. In addition, a charging device 108, an exposure device 110, and a cleaning device 124 are sequentially arranged inside the casing 311 and around the electrophotographic photosensitive member 106. The configurations of the electrophotographic photosensitive member 106, the charging device 108, the exposure device 110, and the cleaning device 124 are as described in the first embodiment of the image forming apparatus. The lubricating oil supply device is housed in a cleaning device 124 as shown in FIG.

  As described above, the process cartridge 300 according to the present embodiment can easily control the wear amount and film thickness unevenness of the photosensitive layer 3 by combining the exposure apparatus 110 including the SLED and the electrophotographic photosensitive member 106. In addition, by further combining the lubricant supply device 200 and the cleaning device 124, the lubricity of the outer peripheral surface of the electrophotographic photosensitive member 106 is enhanced by the supplied lubricant during the electrophotographic process, and the cleaning device 124. The surface is sufficiently cleaned. Thereby, abrasion of the photosensitive layer 3 can be suppressed and potential fluctuation and sensitivity fluctuation can be sufficiently prevented. Therefore, according to the present invention, the characteristics of the self-scanning LED having a small variable light amount and a narrow control width are complemented, and a process cartridge capable of achieving high image quality, high speed, and long life at a high level in a balanced manner is realized.

[Second Embodiment of Process Cartridge]
Next, a second embodiment of the image forming apparatus will be described. In addition, the same code | symbol is attached | subjected about the component same or equivalent to 1st Embodiment, and the overlapping description is abbreviate | omitted.

  The process cartridge according to the present embodiment has the same configuration as the process cartridge shown in FIG. 13 and is different in that the lubricant supply device and the cleaning device 124 are essential elements. That is, the process cartridge 300 according to this embodiment includes the electrophotographic photosensitive member 106, the exposure device 110, the lubricant supply device, and the cleaning device 124. The configurations and arrangements of the exposure apparatus 110, the lubricating oil supply apparatus, and the cleaning apparatus 124 are as described in the first embodiment.

  The electrophotographic photosensitive member 106 is not limited to the one having the function-separated type photosensitive layer 3 as shown in FIG. 11, and is a single-layer type photosensitive material including a charge generation material and a charge transport material in the same layer. It may have the layer 3. Further, when sufficient electrophotographic characteristics are obtained, the undercoat layer 4 and the protective layer 7 may not be provided.

  In the electrophotographic photoreceptor 106 according to this embodiment, when the electrophotographic process is repeated 400,000 cycles, the average wear rate of the photosensitive layer 3 is preferably 15 nm or less per 1,000 cycles, and more preferably 12 nm or less. 9 nm or less is more preferable. Further, the difference between the maximum value and the minimum value of the film thickness in the image forming area of the photosensitive layer 3 is preferably 15% or less of the average film thickness of the charge transport layer 6 before the electrophotographic process, and 12% or less. More preferred is 9% or less. Thereby, higher image quality, higher speed, and longer life can be achieved at a higher level.

  Furthermore, the linear velocity of the electrophotographic photosensitive member 106 is preferably 100 mm / second or more, more preferably 120 mm / second or more, and further preferably 150 mm / second or more, from the viewpoint of increasing the speed. Further, the image resolution in the rotation direction of the electrophotographic photosensitive member 106 is preferably 1200 dpi or more, more preferably 1800 dpi or more, and further preferably 2400 dpi or more, from the viewpoints of high resolution and high image quality. preferable.

  As described above, the process cartridge according to the present embodiment includes 300, the exposure device 110 including the SLED, the lubricant supply device, and the cleaning device 124, so that the wear of the photosensitive layer 3 can be suppressed. It is possible to realize a process cartridge of a self-scanning LED array system capable of achieving a high level, high speed and long life in a balanced manner.

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example and a comparative example, this invention is not limited to a following example at all.

(Preparation of electrophotographic photoreceptor 1)
A hoisted cylindrical aluminum base (outer diameter 30 mm, length 340 mm, wall thickness 1 mm) was prepared. Next, 20 parts by mass of a zirconium compound (trade name: Organochix ZC540, manufactured by Matsumoto Pharmaceutical Co., Ltd.), 2.5 parts by mass of a silane coupling agent (trade name: A1100, manufactured by Nihon Unicar Company), polyvinyl butyral resin (trade name: An undercoat layer forming coating solution was prepared by mixing 2 parts by mass of ESREC BM-S (manufactured by Sekisui Chemical Co., Ltd.) and 43 parts by mass of butanol. This coating solution was applied to the outer peripheral surface of the aluminum substrate by a dip coating method and dried by heating at 150 ° C. for 10 minutes to form an undercoat layer having a thickness of 1.0 μm.

  Next, 15 parts by mass of hydroxygallium phthalocyanine having diffraction peaks at X-ray diffraction spectra at Bragg angles (2θ ± 0.2 °) of 7.3 °, 16.0 °, 24.9 ° and 28.0 ° , 10 parts by weight of vinyl chloride-vinyl acetate copolymer resin (VMCH, manufactured by Nihon Unicar Co., Ltd.) as a binder resin and 300 parts by weight of n-butyl acetate were mixed and dispersed with glass beads for 0.5 hour in a horizontal sand mill. Then, a coating solution for forming a charge generation layer was prepared. The obtained coating solution was dip-coated on the undercoat layer and dried by heating at 100 ° C. for 10 minutes to form a charge generation layer having a thickness of about 0.15 μm.

Next, 2 parts by mass of a compound represented by the following formula (1), 15 parts by mass of a compound represented by the following formula (2), and a polymer compound represented by the following formula (3) (viscosity average molecular weight 39,000) ) 55 parts by mass was dissolved in a mixed solvent of 75 parts by mass of tetrahydrofuran and 25 parts by mass of chlorobenzene to prepare a coating solution for forming a charge transport layer. The obtained coating solution was applied onto the charge generation layer by a dip coating method and dried with hot air at 135 ° C. for 40 minutes to form a charge transport layer having a thickness of 32 μm. Thus, an electrophotographic photoreceptor 1 was obtained.

(Preparation of electrophotographic photoreceptor 2)
A cylindrical aluminum substrate (outer diameter 30 mm, length 340 mm, wall thickness 1 mm) was prepared. Next, 100 parts by mass of zinc oxide (average particle size 70 μm, manufactured by Teica) was stirred and mixed with 500 parts by mass of toluene, and then 1.5 parts by mass of a silane coupling agent (trade name: KBM603, manufactured by Shin-Etsu Chemical Co., Ltd.) Added and stirred for 2 hours. Next, toluene was distilled off under reduced pressure and baked at 150 ° C. for 2 hours to obtain zinc oxide that had been surface-treated. Next, 60 parts by mass of surface-treated zinc oxide, 15 parts by mass of a curing agent (block isocyanate, trade name: Sumidur 3175, manufactured by Sumitomo Bayern Urethane Co., Ltd.), and butyral resin (trade name: BM-1, Sekisui Chemical) 15 parts by mass) were dissolved in 85 parts by mass of methyl ethyl ketone. Next, 38 parts by mass of this solution and 25 parts by mass of methyl ethyl ketone were mixed and subjected to a dispersion treatment for 2 hours with a sand mill using glass beads of 1 mmφ to obtain a dispersion. To the obtained dispersion, 0.005 part by mass of dioctyltin dilaurate as a catalyst was added to obtain a coating liquid for forming an undercoat layer. This coating solution was applied onto an aluminum substrate by a dip coating method, followed by drying and curing at 160 ° C. for 100 minutes to form an undercoat layer having a thickness of 20 μm.

  Next, 15 parts by mass of hydroxygallium phthalocyanine having diffraction peaks at X-ray diffraction spectra at Bragg angles (2θ ± 0.2 °) of 7.3 °, 16.0 °, 24.9 °, and 28.0 ° , 10 parts by weight of vinyl chloride-vinyl acetate copolymer resin (VMCH, manufactured by Nihon Unicar) as a binder resin and 300 parts by weight of n-butyl acetate were mixed and dispersed with glass beads for 0.5 hour in a horizontal sand mill. Then, a coating solution for forming a charge generation layer was prepared. The obtained coating solution was dip-coated on the undercoat layer and dried by heating at 100 ° C. for 10 minutes to form a charge generation layer having a thickness of about 0.15 μm.

  Next, 2 parts by mass of the compound represented by the above formula (1) and 3 parts by mass of the polymer compound (viscosity average molecular weight 39,000) represented by the following formula (3) were 15 parts by mass of tetrahydrofuran and 5 parts by mass of chlorobenzene. A coating solution for forming a charge transport layer was prepared by dissolving in part of the mixed solvent. The obtained coating solution was applied onto the charge generation layer by a dip coating method and dried with hot air at 135 ° C. for 40 minutes to form a charge transport layer having a thickness of 32 μm. Thus, an electrophotographic photoreceptor 2 was obtained.

(Example 1)
Using the electrophotographic photoreceptor 1, an image forming apparatus having the configuration shown in FIG. As the exposure apparatus, a self-scanning LED chip type exposure apparatus provided with LED chips arranged in a staggered pattern as an exposure light source and scanning a light beam according to image data was used. Further, as the lubricant supply device, a lubricant oil supply device having the same configuration as that in FIG. 12 and including zinc stearate as a solid lubricant was used. Elements other than the electrophotographic photosensitive member, the exposure device, and the lubricant supply device were the same as those used in DCC1250 manufactured by Fuji Xerox.

  Next, using the obtained image forming apparatus, a continuous printing test was performed in an environment of about 28 ° C./80% RH. Fuji Xerox PPC paper (L, A4) was used as the continuous printing paper. In this test, the consumption of the lubricant, the wear rate of the photosensitive layer, the life of the photoreceptor and the film thickness unevenness, and the occurrence of image quality streak density unevenness were evaluated. The obtained results are shown in Table 1.

  In Table 1, the lubricant consumption is the consumption of lubricant per A4 size sheet. The wear rate means the average wear rate per 1,000 cycles of the photosensitive layer when the electrophotographic process is repeated 400,000 cycles. The photoconductor life means the number of repetitions of the electrophotographic process until the gradation, resolution, and density uniformity of the image deteriorates, and the upper limit of the number of repetitions is 980,000. That is, “> 980 (kcycle)” in the column of the photoconductor lifetime in Table 1 indicates that the electrophotographic characteristics of the photoconductor were maintained when the electrophotographic process was repeated 980,000 times. Further, the film thickness unevenness means the ratio (%) of the difference between the maximum value and the minimum value of the film thickness in the image forming region of the photosensitive layer with respect to the average film thickness of the charge transport layer before the electrophotographic process.

  In addition, the occurrence of image-quality streak density unevenness is evaluated by a test by the following method. First, the exposure amount of each light emitting point of the SLED was adjusted so that streak density unevenness generated in the rotation direction of the photoconductor did not occur under the conditions of 22 ° C. and 50% RH. Next, a print test was performed at 10 ° C. and 15% RH to examine whether or not image quality streak density unevenness occurred. In Table 1, A indicates that image quality streak density unevenness is not generated or is extremely slight, B indicates image quality streak density unevenness generation is slight, and C indicates that image quality streak density unevenness occurs significantly. means.

(Example 2)
An image forming apparatus is produced by the same method as in Example 1 except that the electrophotographic photosensitive member 2 is used, and the lubricant consumption, the photosensitive layer wear rate, the photosensitive member lifetime and the film thickness unevenness by the continuous printing test, In addition, the occurrence of image quality streak density unevenness was evaluated. The obtained results are shown in Table 1.

(Example 3)
An image forming apparatus was produced by the same method as in Example 1 except that a lubricating oil supply apparatus that fixedly supports a solid lubricant was used, and lubricant consumption, photosensitive layer wear rate, The lifetime of the photoreceptor and film thickness unevenness and the occurrence of image quality streak density unevenness were evaluated. The obtained results are shown in Table 1.

Example 4
An image forming apparatus was prepared in the same manner as in Example 1 except that paraffin wax was used as the solid lubricant, and lubricant consumption, photosensitive layer wear rate, photoconductor lifetime, and film thickness unevenness were measured by a continuous printing test. And the occurrence of streak density unevenness. The obtained results are shown in Table 1.

(Comparative Example 1)
An image forming apparatus was produced by the same method as in Example 1 except that the lubricating oil supply device was not installed, and the lubricant consumption, the photosensitive layer wear rate, the photoreceptor life, and the film thickness unevenness were measured by a continuous printing test. And the occurrence of streak density unevenness. The obtained results are shown in Table 1.

1 is a schematic configuration diagram illustrating a preferred embodiment of an image forming apparatus of the present invention. It is a perspective view which shows the external appearance of a light source array. It is a LED drive circuit diagram incorporated in the light source array. It is a constant current drive circuit diagram. It is a constant voltage drive circuit diagram. It is a density signal (ΦD) generation circuit diagram. 7 is an operation timing chart of FIG. 6. 4 is an operation timing chart of the LED drive circuit of FIG. 3. It is a characteristic view which shows the LED light emission state of the LED drive circuit of FIG. It is a drive circuit diagram in SLED single-piece | unit. 1 is a schematic cross-sectional view showing an example of a first electrophotographic photosensitive member according to the present invention. It is a disassembled perspective view which shows an example of a lubricant supply apparatus. It is a schematic block diagram which shows an example of the apparatus with which the cleaning apparatus and the lubricant supply apparatus were integrated. It is a schematic block diagram which shows suitable one Embodiment of a process cartridge.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 100 ... Image forming apparatus 106 ... Electrophotographic photosensitive member 108 ... Charging apparatus 110 ... Exposure apparatus 116 ... Developing apparatus 120 ... Transfer apparatus.

Claims (7)

An image forming apparatus for sequentially performing an electrophotographic process including charging, exposure, development and transfer,
An electrophotographic photoreceptor;
An LED array having a plurality of LEDs is provided as an exposure light source, and a self-scanning LED array system is adopted in which an electrostatic latent image is formed by scanning a light beam on the electrophotographic photosensitive member according to image data. An exposure apparatus,
When the electrophotographic photosensitive member has a conductive substrate and a photosensitive layer having a charge generation layer and a charge transport layer formed on the conductive substrate, and the electrophotographic process is repeated 400,000 cycles, the photosensitive layer The average wear rate of the charge transport layer is 15 nm or less per 1,000 cycles, and the difference between the maximum value and the minimum value of the film thickness in the image forming region of the photosensitive layer is the average of the charge transport layer before the electrophotographic process is performed. An image forming apparatus having a thickness of 15% or less. A cleaning device for removing residual toner adhered to the electrophotographic photosensitive member after transfer;
A lubricant supply device for supplying a lubricant to the electrophotographic photosensitive member;
The image forming apparatus according to claim 1, further comprising: An image forming apparatus that sequentially performs an electrophotographic process including charging, exposure, development, transfer, and cleaning,
An electrophotographic photoreceptor;
An LED array having a plurality of LEDs is provided as an exposure light source, and a self-scanning LED array system is adopted in which an electrostatic latent image is formed by scanning a light beam on the electrophotographic photosensitive member according to image data. An exposure device;
A cleaning device for removing residual toner adhered to the electrophotographic photosensitive member after transfer;
A lubricant supply device for supplying a lubricant to the electrophotographic photosensitive member;
An image forming apparatus comprising:   The electrophotographic photosensitive member has a substantially cylindrical shape that is rotatably provided around a first axis, and the lubricant supply device is provided by the cleaning device based on the moving direction of the outer peripheral surface of the electrophotographic photosensitive member. 4. The image forming apparatus according to claim 2, wherein the image forming apparatus is also disposed upstream.   The lubricant supply device is provided so as to be rotatable about a second axis parallel to the first axis, a rotating brush whose brush tip contacts the outer peripheral surface of the electrophotographic photosensitive member, and the second axis And a support member that supports the solid lubricant so as to be swingable about a parallel third axis, and generates a moment from the support member toward the rotating brush around the third axis. The solid lubricant is brought into contact with the rotating brush by the moment, and the lubricant adhering to the rotating brush is supplied to the electrophotographic photosensitive member. The image forming apparatus according to claim 1. An electrophotographic photoreceptor;
An LED array having a plurality of LEDs is provided as an exposure light source, and a self-scanning LED array system is adopted in which an electrostatic latent image is formed by scanning a light beam on the electrophotographic photosensitive member according to image data. An exposure device;
With
When the electrophotographic photosensitive member has a conductive substrate and a photosensitive layer having a charge generation layer and a charge transport layer formed on the conductive substrate, and the electrophotographic process is repeated 400,000 cycles, the photosensitive layer The average wear rate of the charge transport layer is 15 nm or less per 1,000 cycles, and the difference between the maximum value and the minimum value of the film thickness in the image forming region of the photosensitive layer is the average of the charge transport layer before the electrophotographic process is performed. A process cartridge having a thickness of 15% or less. An electrophotographic photoreceptor comprising a conductive substrate and a photosensitive layer formed on the conductive substrate;
An LED array having a plurality of LEDs is provided as an exposure light source, and a self-scanning LED array system is adopted in which an electrostatic latent image is formed by scanning a light beam on the electrophotographic photosensitive member according to image data. An exposure device;
A cleaning device for removing residual toner adhered to the electrophotographic photosensitive member after transfer;
A lubricant supply device for supplying a lubricant to the electrophotographic photosensitive member;
A process cartridge comprising:

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