Image forming apparatus

Abstract

To provide an image forming apparatus that can prevent abnormal wear to maintain a cleaning performance.SOLUTION: An image forming apparatus has: a photoreceptor; and a cleaning blade having an elastic member that is in contact with a surface of the photoreceptor and removes an attachment attached to the surface of the photoreceptor. The photoreceptor has a conductive support, and a photosensitive layer and a surface layer that are sequentially laminated on the conductive support. The surface layer has a binder resin and particles. The surface layer has Martens hardness of 150 N / mm2 or more and less than 180 N / mm2, and an elastic power of 35% or more and less than 45%. In the cleaning blade, the elastic member has a base material layer and a surface layer. The surface layer has a tip ridge part. The surface layer has domains having a polysiloxane structure having an average dispersion diameter of 0.1 μm or more and 5.0 μm or less in an area from a surface of the elastic member including the tip ridge part to a depth of 100 μm.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an image forming apparatus. Set

Background Art

[0002] Conventionally, in an electrophotographic image forming apparatus, after transferring a toner image onto transfer paper or an intermediate transfer member, unnecessary transfer residual toner adhering to the surface of the photoreceptor is removed by a cleaning device. As a cleaning member of the cleaning device, there is known one using a strip-shaped cleaning blade having a simple configuration and excellent cleaning performance.

[0003] This cleaning blade is made of an elastic body such as polyurethane rubber. The cleaning blade has its base end supported by a support member, presses the tip ridge line portion against the circumferential surface of the photoreceptor, and blocks and scrapes off the toner remaining on the photoreceptor to remove it.

[0004] Also, in order to meet the recent demand for high image quality, there is known an image forming apparatus using toner having a small particle size and being close to a spherical shape (hereinafter referred to as polymerized toner) formed by a polymerization method or the like. This polymerized toner has characteristics such as high transfer efficiency compared to conventional pulverized toner, and can meet the above requirements.

[0005] However, the polymerized toner has a problem that it is difficult to sufficiently remove it even when trying to remove it from the surface of the photoreceptor using a cleaning blade, resulting in cleaning failure. This is because the polymerized toner having a small particle size and excellent sphericity passes through a slight gap formed between the blade and the photoreceptor.

[0006] In order to suppress such passing of the polymerized toner, it is necessary to increase the contact pressure between the photoreceptor and the cleaning blade to enhance the cleaning ability.

[0007] ​For example, Patent Document 1 describes a cleaning blade composed of an elastic blade (elastic body blade) whose surface is subjected to low-friction treatment by impregnation with at least one selected from an isocyanate compound, a fluorine compound, and a silicone compound, and a surface layer made of an ultraviolet curable resin harder than the elastic blade that covers the tip ridge line portion of the elastic blade.

[0008] Patent Document 2 describes a cleaning blade in which, as a method of providing a hard surface layer on an elastic blade to increase the hardness of the tip ridge line portion, a surface layer made of a resin having a pencil hardness of B to 6H is provided on at least the tip ridge line portion of the elastic blade.

[0009] Patent Document 3 describes a cleaning blade in which a silicone-containing ultraviolet curable material is impregnated into an elastic blade to swell it, and then subjected to ultraviolet irradiation treatment to form a surface layer harder than the elastic blade at least at the contact portion of the cleaning blade that contacts the photoreceptor.

[0010] Further, Patent Document 4 describes a cleaning blade in which an acrylate polymer is impregnated from the surface of the cleaning blade to a depth of 5 μm or more and 100 μm or less, and then the acrylate polymer is laminated on the surface of the cleaning blade and subjected to ultraviolet irradiation treatment to cure this ultraviolet curable material.

Summary of the Invention

Problems to be Solved by the Invention

[0011] However, when the contact pressure of the cleaning blade is increased, the frictional force between the photoreceptor and the cleaning blade increases, so that the tip ridge line portion of the cleaning blade is turned up. Further, due to such turning up of the cleaning blade, local wear (abnormal wear) and cleaning failure (a state where toner cannot be normally cleaned) due to the loss of the tip ridge line portion occur.

[0012] An object of the present invention is to provide an image forming apparatus that can suppress abnormal wear and maintain good cleaning performance.

Means for Solving the Problem

[0013] In order to solve the above-described problems, one aspect of the present invention is an image forming apparatus including a photoreceptor and a cleaning blade having an elastic member that contacts the surface of the photoreceptor and removes deposits adhering to the surface of the photoreceptor. The photoreceptor includes a conductive support and a photosensitive layer and a surface layer sequentially laminated on the conductive support. The surface layer includes a polycarbonate resin as a binder resin and any one of alumina particles, fluorine-containing resin particles, and silica particles as particles, and has a Martens hardness of 150 N / mm 2 or more and less than 180 N / mm 2 and an elastic work rate of 35% or more and less than 45%. The cleaning blade has a base material layer and a surface layer as the elastic member. The surface layer has a tip ridge line portion, and the surface layer has a domain having a polysiloxane structure with an average dispersion diameter of 0.1 μm or more and 5.0 μm or less in a region from the surface including the tip ridge line portion of the elastic member to a depth of 100 μm. Containing dimethyl silicone oil It is characterized by having a domain having a polysiloxane structure with an average dispersion diameter of 0.1 μm or more and 5.0 μm or less.

Advantages of the Invention

[0014] According to one aspect of the present invention, it is possible to provide an image forming apparatus that suppresses abnormal wear and maintains good cleaning performance.

Brief Description of the Drawings

[0015]

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Mode for Carrying Out the Invention

[0016] Hereinafter, embodiments of the present invention will be described.

[0017] <Image forming apparatus> The image forming apparatus according to this embodiment includes a photoreceptor and a cleaning blade having an elastic member that contacts the surface of the photoreceptor and removes deposits adhering to the surface of the photoreceptor.

[0018] In the image forming apparatus of the present embodiment, the photosensitive member has a conductive support and a photosensitive layer and a surface layer sequentially laminated on the conductive support. The surface layer of the photosensitive member has a binder resin and particles. The Martens hardness of the surface layer of the photosensitive member is 150 N / mm 2 or more and less than 180 N / mm 2 and the elastic work ratio is 35% or more and less than 45%.

[0019] In the image forming apparatus of the present embodiment, the cleaning blade has an elastic member having a base material layer and a surface layer, and the surface layer has a tip ridge line portion. The surface layer of the cleaning blade has a domain having a polysiloxane structure with an average dispersion diameter of 0.1 μm or more and 5.0 μm or less in a region from the surface including the tip ridge line portion of the elastic member to a depth of 100 μm.

[0020] FIG. 1 is a schematic configuration diagram of an electrophotographic printer showing an example of the image forming apparatus according to the present embodiment. Hereinafter, the image forming apparatus of the present embodiment will be described using the printer 500 shown in FIG. 1.

[0021] The printer 500 includes four image forming units 1Y, 1C, 1M, and 1K for yellow, magenta, cyan, and black (hereinafter referred to as Y, C, M, and K). These use Y, C, M, and K toners of different colors as image forming substances for forming images, but have the same configuration otherwise.

[0022] Above the four image forming units 1, a transfer unit 60 including an intermediate transfer belt 14 as an intermediate transfer member is disposed. The toner images of respective colors formed on the surfaces of the photosensitive members 3Y, 3C, 3M, and 3K provided in the respective image forming units 1Y, 1C, 1M, and 1K, which will be described in detail later, are transferred in an overlapping manner onto the surface of the intermediate transfer belt 14.

[0023] Below the four image forming units 1, an optical writing unit 40 as a latent image forming means is disposed. The optical writing unit 40 irradiates the photoreceptors 3Y, 3C, 3M, 3K of each image forming unit 1Y, 1C, 1M, 1K with the laser beam L emitted based on the image information. Thereby, electrostatic latent images for Y, C, M, and K are formed on the photoreceptors 3Y, 3C, 3M, 3K.

[0024] Note that the optical writing unit 40 irradiates the photoreceptors 3Y, 3C, 3M, 3K through a plurality of optical lenses and mirrors while deflecting the laser beam L emitted from the light source by a polygon mirror 41 that is rotationally driven by a motor. Further, instead of such a configuration, one that performs optical scanning using an LDE array can also be adopted.

[0025] Below the optical writing unit 40, a first paper feed cassette 151 and a second paper feed cassette 152 are disposed so as to overlap in the vertical direction. In these paper feed cassettes, stacks of a plurality of sheets of transfer paper P, which is a recording medium, are accommodated, and the first paper feed roller 151a and the second paper feed roller 152a are respectively in contact with the top transfer paper P.

[0026] When the first paper feed roller 151a is rotationally driven counterclockwise in FIG. 1 by a driving means (not shown), the top transfer paper P in the first paper feed cassette 151 is discharged toward a paper feed path 153 disposed so as to extend in the vertical direction. Also, when the second paper feed roller 152a is rotationally driven counterclockwise in FIG. 1 by a driving means (not shown), the top transfer paper P in the second paper feed cassette 152 is discharged toward the paper feed path 153.

[0027] In the paper feed path 153, a plurality of pairs of conveying rollers 154 are disposed. The transfer paper P fed into the paper feed path 153 is conveyed through the paper feed path 153 from the lower side to the upper side in FIG. 1 while being sandwiched between the rollers of these pairs of conveying rollers 154.

[0028] Upstream of the roller pair 154 in the conveyance direction of the paper feed path 153, a registration roller pair 55 is disposed. As soon as the registration roller pair 55 sandwiches the transfer paper P sent from the conveyance roller pair 154 between the rollers, the rotation of both rollers is temporarily stopped. Then, the transfer paper P is sent out toward the secondary transfer nip described later at an appropriate timing.

[0029] FIG. 2 is a configuration diagram showing a schematic configuration of one of the four image forming units 1. As shown in FIG. 2, the image forming unit 1 includes a drum-shaped photoreceptor 3 as a photoreceptor. Although the photoreceptor 3 shows a drum shape, it may be in the form of a sheet or an endless belt.

[0030] Around the photoreceptor 3, a charging roller 4, a developing device 5, a cleaning device 6, a primary transfer roller 7, a lubricant application device 10, and a charge elimination lamp (not shown) are arranged.

[0031] The charging roller 4 is a charging member provided in a charging device as a charging means. The charging roller 4 is disposed in non-contact with the photoreceptor 3 at a predetermined distance and charges the photoreceptor 3 to a predetermined polarity and a predetermined potential.

[0032] The surface of the photoreceptor 3 uniformly charged by the charging roller 4 is irradiated with laser light L based on image information from an optical writing unit 40 which is a latent image forming means, and an electrostatic latent image is formed. Note that a charging roller cleaner 8 is provided in contact with the charging roller 6, and foreign matter attached to the charging roller 6 is cleaned.

[0033] The developing device 5 constitutes developing means for toner imaging the latent image formed on the surface of the photoreceptor 3. The developing device 5 has a developing roller 51 as a developer carrier. A developing bias is applied to the developing roller 51 from a power source (not shown). Inside the casing of the developing device 5, a supply screw 52 and a stirring screw 53 for stirring the developer accommodated in the casing while conveying it in opposite directions to each other are provided.

[0034] The developing device 5 is also provided with a doctor 54 for regulating the developer carried on the developing roller 51. The toner in the developer agitated and conveyed by the two screws of the supply screw 52 and the agitation screw 53 is charged to a predetermined polarity. Then, the developer is pumped onto the surface of the developing roller 51, and the pumped developer is regulated by the doctor 54, and the toner adheres to the latent image on the photoreceptor 3 in the developing area facing the photoreceptor 3.

[0035] The cleaning device 6 is a cleaning means for cleaning the toner remaining on the photoreceptor 3 after transferring the toner image to the intermediate transfer belt 14. The cleaning device 6 has a fur brush 101, a cleaning blade 62, etc. The cleaning blade 62 is in contact with the photoreceptor 3 in a counter direction with respect to the surface movement direction of the photoreceptor 3. Details of the cleaning blade 62 will be described later.

[0036] The primary transfer roller 7 is a primary transfer member provided in a primary transfer device as a primary transfer means for transferring the toner image on the surface of the photoreceptor 3 to the intermediate transfer belt 14.

[0037] The lubricant application device 10 is a lubricant application means for applying a lubricant onto the surface of the photoreceptor 3 after being cleaned by the cleaning device 6. A charge elimination lamp (not shown) constitutes a charge elimination means for eliminating the surface potential of the photoreceptor 3 after cleaning. The lubricant application device 10 includes a solid lubricant 103, a lubricant pressure spring 103a, etc., and uses the fur brush 101 as an application brush for applying the solid lubricant 103 onto the photoreceptor 3.

[0038] Note that the lubricant application device 10 is an example of a lubricant application part constituting a part of the image forming apparatus according to the present embodiment.

[0039] The solid lubricant 103 is held by the bracket 103b and is pressed toward the fur brush 101 by the lubricant pressure spring 103a. Then, the solid lubricant 103 is scraped off by the fur brush 101 that rotates in the direction of being carried along with respect to the rotation direction of the photoreceptor 3, and the lubricant is applied onto the photoreceptor 3. By applying the lubricant to the photoreceptor, the coefficient of friction on the surface of the photoreceptor 3 is maintained at 0.2 or less during non-image formation.

[0040] In this embodiment, as the charging device method, a non-contact proximity arrangement method in which the charging roller 4 is brought close to the photoreceptor 3 is used. However, as the charging device, known configurations such as a corotron, a scorotron, and a solid charger (solid state charger) can be used. Among these charging methods, the contact charging method or the non-contact proximity arrangement method is preferable in terms of having merits such as high charging efficiency, low ozone generation amount, and possibility of downsizing the device.

[0041] For light sources such as the laser light L of the light writing unit 40 and the charge removal lamp, various light emitters such as a fluorescent lamp, a tungsten lamp, a halogen lamp, a mercury lamp, a sodium lamp, a light emitting diode (LED), a semiconductor laser (LD), and an electroluminescence (EL) can be used.

[0042] In addition, in order to irradiate only light in a desired wavelength range, various filters such as a sharp cut filter, a band pass filter, a near infrared cut filter, a dichroic filter, an interference filter, and a color temperature conversion filter can also be used.

[0043] Among these light sources, the light emitting diode and the semiconductor laser are preferably used because they have high irradiation energy and have long wavelength light of 600 to 800 nm.

[0044] The transfer unit 60 includes, in addition to the intermediate transfer belt 14, a belt cleaning unit 162, a first bracket 63, a second bracket 64, and the like. It also includes four primary transfer rollers 7Y, 7C, 7M, 7K, a secondary transfer backup roller 66, a driving roller 67, an auxiliary roller 68, a tension roller 69, and the like.

[0045] The intermediate transfer belt 14 is stretched over these eight roller members and moves endlessly counterclockwise in FIG. 1 by the rotational drive of the driving roller 67. The four primary transfer rollers 7Y, 7C, 7M, 7K sandwich the endlessly moving intermediate transfer belt 14 between the photoreceptors 3Y, 3C, 3M, 3K to form primary transfer nips respectively.

[0046] Then, a transfer bias of the opposite polarity (for example, positive) to the toner is applied to the back surface (inner peripheral surface of the loop) of the intermediate transfer belt 14. As the intermediate transfer belt 14 moves endlessly and sequentially passes through the primary transfer nips for Y, C, M, and K, it superposes the Y, C, M, and K toner images on the photoreceptors 3Y, 3C, 3M, 3K on its surface and performs primary transfer. As a result, a four-color superposed toner image (hereinafter referred to as a four-color toner image) is formed on the intermediate transfer belt 14.

[0047] The secondary transfer backup roller 66 sandwiches the intermediate transfer belt 14 between it and a secondary transfer roller 70 disposed outside the loop of the intermediate transfer belt 14 to form a secondary transfer nip. The resist roller pair 55 described above feeds the transfer paper P sandwiched between the rollers toward the secondary transfer nip at a timing that can synchronize with the four-color toner image on the intermediate transfer belt 14.

[0048] The four-color toner image on the intermediate transfer belt 14 is collectively secondarily transferred to the transfer paper P within the secondary transfer nip under the influence of a secondary transfer electric field formed between the secondary transfer roller 70 to which a secondary transfer bias is applied and the secondary transfer backup roller 66, and the nip pressure. Then, combined with the white color of the transfer paper P, it becomes a full-color toner image.

[0049] After passing through the secondary transfer nip, the intermediate transfer belt 14 has residual transfer toner that was not transferred to the transfer paper P adhering to it. This is cleaned by the belt cleaning unit 162. Note that the belt cleaning unit 162 has a belt cleaning blade 162a in contact with the surface of the intermediate transfer belt 14, and thereby scrapes off and removes the residual transfer toner on the intermediate transfer belt 14.

[0050] The first bracket 63 of the transfer unit 60 is configured to swing at a predetermined rotation angle about the rotation axis of the auxiliary roller 68 in accordance with the on / off driving of a solenoid (not shown).

[0051] When the printer 500 forms a monochrome image, the solenoid drives the first bracket 63 to rotate counterclockwise slightly in FIG. 1. Due to this rotation, the primary transfer rollers 7Y, 7C, 7M for Y, C, and M revolve counterclockwise in FIG. 1 about the rotation axis of the auxiliary roller 68, separating the intermediate transfer belt 14 from the photoreceptors 3Y, 3C, 3M for Y, C, and M.

[0052] Then, only the imaging unit 1K for K among the four imaging units 1Y, 1C, 1M, 1K is driven to form a monochrome image. Thereby, it is possible to avoid the consumption of each member constituting the imaging unit 1 due to driving the imaging units 1 for Y, C, and M uselessly during monochrome image formation.

[0053] Above the secondary transfer nip in FIG. 1, a fixing unit 80 is disposed. This fixing unit 80 includes a pressure heating roller 81 that incorporates a heat source such as a halogen lamp, and a fixing belt unit 82.

[0054] The fixing belt unit 82 includes a fixing belt 84 as a fixing member, a heating roller 83 containing a heat source such as a halogen lamp, a tension roller 85, a driving roller 86, a temperature sensor (not shown), and the like. And the endless fixing belt 84 is endlessly moved in the counterclockwise direction in FIG. 1 while being stretched by the heating roller 83, the tension roller 85, and the driving roller 86.

[0055] In the process of this endless movement, the fixing belt 84 is heated from the back side by the heating roller 83. At the location where the fixing belt 84 thus heated is wound around the heating roller 83, a pressure heating roller 81 that is rotationally driven in the clockwise direction in FIG. 1 abuts from the front side. Thereby, a fixing nip is formed where the pressure heating roller 81 and the fixing belt 84 abut.

[0056] Outside the loop of the fixing belt 84, a temperature sensor (not shown) is disposed so as to face the surface of the fixing belt 84 with a predetermined gap therebetween, and detects the surface temperature of the fixing belt 84 immediately before entering the fixing nip. This detection result is sent to a fixing power supply circuit (not shown). The fixing power supply circuit controls the on / off supply of power to the heat source included in the heating roller 83 and the pressure heating roller 81 based on the detection result by the temperature sensor.

[0057] The transfer paper P that has passed through the above-described secondary transfer nip is sent into the fixing unit 80 after being separated from the intermediate transfer belt 14. And in the process of being conveyed from the lower side to the upper side in FIG. 1 while being sandwiched by the fixing nip in the fixing unit 80, the full-color toner image is fixed on the transfer paper P by being heated and pressed by the fixing belt 84.

[0058] The transfer paper P thus subjected to the fixing process is discharged outside the machine after passing between the rollers of the paper discharge roller pair 87. A stack portion 88 is formed on the upper surface of the housing of the printer 500 main body, and the transfer paper P discharged outside the machine by the paper discharge roller pair 87 is sequentially stacked on this stack portion 88.

[0059] Above the transfer unit 60, four toner cartridges 100Y, 100C, 100M, and 100K for accommodating Y, C, M, and K toners are arranged. The Y, C, M, and K toners in the toner cartridges 100Y, 100C, 100M, and 100K are appropriately supplied to the developing devices 5Y, 5C, 5M, and 5K of the image forming units 1Y, 1C, 1M, and 1K.

[0060] These toner cartridges 100Y, 100C, 100M, and 100K are detachable from the printer main body independently of the image forming units 1Y, 1C, 1M, and 1K.

[0061] Next, the image forming operation in the printer 500 will be described.

[0062] When a print execution signal is received from an operation unit (not shown) or the like, a predetermined voltage or current is sequentially applied to the charging roller 4 and the developing roller 51 at a predetermined timing. Similarly, a predetermined voltage or current is sequentially applied to light sources such as the optical writing unit 40 and the charge eliminating lamp at a predetermined timing. Also, in synchronization with this, the photosensitive drum 3 is rotationally driven in the direction of the arrow in FIG. 1 by a photosensitive drum driving motor (not shown) as a driving means.

[0063] When the photosensitive drum 3 rotates in the direction of the arrow in FIG. 1, first, the surface of the photosensitive drum 3 is uniformly charged to a predetermined potential by the charging roller 4. Then, laser light L corresponding to the image information is irradiated onto the photosensitive drum 3 from the optical writing unit 40, and the portion of the surface of the photosensitive drum 3 irradiated with the laser light L is discharged to form an electrostatic latent image.

[0064] The surface of the photosensitive drum 3 on which the electrostatic latent image is formed is rubbed by the magnetic brush of the developer formed on the developing roller 51 at the portion facing the developing device 5. At this time, the negatively charged toner on the developing roller 51 moves toward the electrostatic latent image side by a predetermined developing bias applied to the developing roller 51, and is toner-imaged (developed).

[0065] In each image forming unit 1, a similar image forming process is executed, and toner images of respective colors are formed on the surfaces of the photoreceptors 3Y, 3C, 3M, and 3K of each image forming unit 1Y, C, M, K.

[0066] Thus, in the printer 500, the electrostatic latent image formed on the photoreceptor 3 is reversely developed by the toner charged negatively by the developing device 5. In this embodiment, an example using a non-contact charging roller system of N / P (negative-positive: a mode in which toner adheres to a portion with a lower potential) has been described, but the present invention is not limited thereto.

[0067] The toner images of respective colors formed on the surfaces of the photoreceptors 3Y, 3C, 3M, and 3K are sequentially primary transferred so as to overlap on the surface of the intermediate transfer belt 14. Thereby, a four-color toner image is formed on the intermediate transfer belt 14.

[0068] The four-color toner image formed on the intermediate transfer belt 14 is fed from the first paper feed cassette 151 or the second paper feed cassette 152, passes between the rollers of the registration roller pair 55, and is transferred to the transfer paper P fed to the secondary transfer nip. At this time, the transfer paper P is once stopped while being sandwiched by the registration roller pair 55, and is supplied to the secondary transfer nip in synchronization with the leading edge of the image on the intermediate transfer belt 14.

[0069] The transfer paper P onto which the toner image has been transferred is separated from the intermediate transfer belt 14 and conveyed to the fixing unit 80. Then, as the transfer paper P onto which the toner image has been transferred passes through the fixing unit 80, the toner image is fixed on the transfer paper P by the action of heat and pressure. The transfer paper P onto which the toner image has been fixed is discharged outside the printer 500 device and stacked in the stack unit 88.

[0070] On one hand, the surface of the intermediate transfer belt 14 on which the toner image has been transferred to the transfer paper P by the secondary transfer nip is cleaned of the residual toner on the surface by the belt cleaning unit 162. Also, the surface of the photoreceptor 3 on which the toner images of respective colors have been transferred to the intermediate transfer belt 14 by the primary transfer nip is cleaned of the residual toner after transfer by the cleaning device 6, lubricant is applied by the lubricant application device 10, and then it is discharged by the discharge lamp.

[0071] As shown in FIG. 1, the image forming unit 1 of the printer 500 includes a photoreceptor 3, a charging roller 4, a developing device 5, a cleaning device 6, a lubricant application device 10, etc. as process means, which are provided (housed) in a frame body 2. And the image forming unit 1 is integrally detachable from the main body of the printer 500 as a process cartridge.

[0072] In the printer 500, the image forming unit 1 integrally replaces the photoreceptor 3 as a process cartridge and each process means, but it is not limited to this configuration. For example, the printer 500 may be configured to replace with new ones in units such as the photoreceptor 3, the charging roller 4, the developing device 5, the cleaning device 6, and the lubricant application device 10.

[0073] Next, the toner suitable for the printer 500 of the present embodiment will be described.

[0074] As the toner used in the printer 500, in order to improve the image quality, it is preferable to use a polymer toner manufactured by a suspension polymerization method, an emulsion polymerization method, or a dispersion polymerization method that is easily made highly round and has a small particle size. For example, it is preferable to use a polymer toner having a circularity of 0.97 or more and a volume average particle size of 5.5 μm or less. By using one having an average circularity of 0.97 or more and a volume average particle size of 5.5 μm, an image with higher resolution can be formed.

[0075] Here, the circularity is the average circularity measured by a flow type particle image analyzer FPIA-2000 (manufactured by Toa Medical Electronics Co., Ltd., trade name).

[0076] Specifically, 100 to 150 ml of water from which impurities and solids have been removed in advance in a container is added with 0.1 to 0.5 ml of a surfactant, preferably an alkylbenzene sulfonate, as a dispersant, and further about 0.1 to 0.5 g of a measurement sample (toner) is added. Then, the suspension in which the toner is dispersed is subjected to dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes, and the one with a dispersion liquid concentration of 3,000 to 10,000 particles / μl is set in the above analyzer to measure the shape and distribution of the toner.

[0077] Regarding the volume average particle size, it can be determined by the Coulter counter method. Specifically, data on the number distribution and volume distribution of the toner measured by a Coulter Multisizer 2e type (manufactured by Coulter) is sent to a personal computer via an interface (manufactured by Nikka Kikai Co., Ltd.) for analysis.

[0078] More specifically, a 1% NaCl aqueous solution using primary sodium chloride is prepared as an electrolyte solution. Then, 0.1 to 5 ml of a surfactant, preferably an alkylbenzene sulfonate, as a dispersant is added to 100 to 150 ml of this electrolytic aqueous solution. Further, 2 to 20 mg of toner as a test sample is added thereto, and dispersion treatment is performed with an ultrasonic disperser for about 1 to 3 minutes.

[0079] Then, 100 to 200 ml of the electrolytic aqueous solution is placed in another beaker, and the solution after dispersion treatment is added thereto to a predetermined concentration and applied to the above Coulter Multisizer 2e type. As the aperture, a 100 μm one is used, and the particle sizes of 50,000 toner particles are measured.

[0080] As channels, those with a size of 2.00 μm or more and less than 2.52 μm; 2.52 μm or more and less than 3.17 μm; 3.17 μm or more and less than 4.00 μm; 4.00 μm or more and less than 5.04 μm; 5.04 μm or more and less than 6.35 μm; 6.35 μm or more and less than 8.00 μm; 8.00 μm or more and less than 10.08 μm; 10.08 μm or more and less than 12.70 μm; 12.70 μm or more and less than 16.00 μm; 16.00 μm or more and less than 20.20 μm; 20.20 μm or more and less than 25.40 μm; 25.40 μm or more and less than 32.00 μm; 32.00 μm or more and less than 40.30 μm are used, targeting toner particles with a particle size of 2.00 μm or more and 32.0 μm or less.

[0081] Then, based on the relational expression "volume average particle size = ΣXfV / ΣfV", the volume average particle size is calculated. Here, "X" is the representative diameter in each channel, "V" is the equivalent volume at the representative diameter of each channel, and "f" is the number of particles in each channel.

[0082] In such a polymerized toner, even if it is attempted to remove it with a conventional cleaning blade in the same manner as when removing a conventional pulverized toner from the surface of the photoreceptor, the polymerized toner cannot be sufficiently removed from the surface of the photoreceptor, resulting in cleaning defects. Therefore, when attempting to increase the contact pressure of the cleaning blade against the photoreceptor to improve the cleaning performance, there is a problem that the cleaning blade wears out prematurely.

[0083] Note that FIG. 3 is a conceptual diagram of problems occurring in a conventional cleaning blade. Also, when the frictional force between the cleaning blade and the photoreceptor increases, the portion of the cleaning blade in contact with the surface of the photoreceptor (the blade tip ridge line portion) is pulled and turned up in the moving direction of the photoreceptor. When the portion of the cleaning blade in contact with the photoreceptor turns up, various problems such as abnormal noise, vibration, wear (edge wear) and breakage of the blade tip ridge line portion occur.

[0084] As a result of intensive studies, the inventors of the present invention have found an image forming apparatus in which the surface layer of the cleaning blade has domains (regions) having a polysiloxane structure with an average dispersion diameter of 0.1 μm or more and 5.0 μm or less in a region from the surface including the tip ridge line portion to a depth of 100 μm.

[0085] In the image forming apparatus having such a configuration, it has been found that abnormal wear of the photoreceptor and the cleaning blade and the occurrence of curling at the tip ridge line portion of the cleaning blade are suppressed. In this image forming apparatus, it has further been found that the followability of the tip ridge line portion of the cleaning blade to the photoreceptor can be improved over a long period of time, and good cleaning performance can be maintained.

[0086] <Cleaning blade> Here, an example of the cleaning blade in the present embodiment will be described with reference to FIGS. 4 and 5. FIG. 4 is an explanatory view of a state in which the cleaning blade 62 is in contact with the surface of the photoreceptor 3, and FIG. 5 is a perspective view of the cleaning blade 62.

[0087] In FIGS. 4 and 5, the cleaning blade 62 has a support member 621 and an elastic member 624. The elastic member 624 has a base material layer (base material) 622 and a surface layer 623. In the present embodiment, the base material layer 622 has a strip shape. Further, the cleaning blade 62 has a blade tip surface 62a, a blade lower surface 62b, and a tip ridge line portion 62c (hereinafter, may be referred to as a contact portion or an edge portion).

[0088] In the present embodiment, on the longitudinal surface of the base material layer 622 constituting the elastic member 624, the surface facing the downstream side B in the traveling direction (the rotation directions indicated by A and B in FIG. 4) of the photoreceptor 3 (member to be cleaned) is referred to as the lower surface of the base material layer 622. Further, the tip surface of the base material layer 622 facing the upstream side A in the rotation direction of the member to be cleaned including the tip ridge line portion 62c of the base material layer 622 is referred to as the tip surface of the base material layer 622.

[0089] In FIG. 4, on the longitudinal surface of the elastic member 624, the surface facing the downstream side B in the rotation direction of the member to be cleaned corresponds to the lower surface 62b of the blade. Also, the tip surface facing the upstream side A in the rotation direction of the member to be cleaned including the tip ridge line portion 62c of the elastic member 624 corresponds to the blade tip surface 62a.

[0090] Further, the contact portion of the elastic member 624 that contacts the surface of the member to be cleaned includes the tip ridge line portion 62c of the elastic member 624. Also, when the tip ridge line portion 62c is curled or when the line pressure is high, a part of the blade tip surface 62a can also become the contact portion.

[0091] Note that the cleaning blade 62 is an example of a cleaning blade that constitutes a part of the image forming apparatus according to the present embodiment. Also, the cleaning blade 62 is an example of a cleaning blade according to the present embodiment.

[0092] <Elastic member> The elastic member 624 contacts the surface of the photoreceptor 3 (member to be cleaned) and removes the deposits adhering to the surface of the member to be cleaned. The elastic member 624 has at least a base material layer 622 and a surface layer 623, and further has other parts as necessary.

[0093] Since the elastic member 624 has the base material layer 622 and the surface layer 623, even when the elastic member 624 has a siloxane-based compound or a domain having a polysiloxane structure, the dimensional accuracy in the longitudinal direction of the elastic member 624 is good. The reason is considered as follows.

[0094] When an elastic member is made of only a single-layer urethane rubber containing a siloxane-based compound, when cutting the elastic member to the size for use, the cutting blade slips due to the low friction coefficient derived from the domain having a siloxane-based compound or a polysiloxane structure on the surface. As a result, it is difficult to obtain dimensional accuracy for an elastic member made of only a single-layer urethane rubber containing a siloxane-based compound.

[0095] On the other hand, when the elastic member 624 has a base material layer 622 and a surface layer 623 having a domain with a siloxane-based compound or a polysiloxane structure as in this embodiment, a cutting blade can be inserted from the side of the base material layer 622, enabling cutting with high dimensional accuracy.

[0096] If the dimensional accuracy in the longitudinal direction is poor, when the blade is pressed against the photoreceptor, the deviation of the pressure in the longitudinal direction becomes large (the pressure is high where the dimension is long and low where the dimension is short). If there is a large deviation in the pressing pressure, toner will slip through where the pressure is weak, deteriorating the image quality. As the deviation in the longitudinal direction, for example, 100 μm or less is preferable.

[0097] FIG. 6 shows an example of a cleaning blade with good dimensional accuracy. In the cleaning blade 62 shown in FIG. 6, the length X from the end of the support member 621 on the side opposite to the elastic member 624 side to the tip ridge line portion 62c of the elastic member 624 is uniform in the longitudinal direction. In this case, when the blade is pressed against the photoreceptor 3, the deviation of the pressure in the longitudinal direction is small.

[0098] FIG. 7 shows an example of a cleaning blade with poor dimensional accuracy. In the cleaning blade 62 shown in FIG. 7, the length X from the end of the support member 621 on the side opposite to the elastic member 624 side to the tip ridge line portion 62c of the elastic member 624 is non-uniform in the longitudinal direction. In this case, when the cleaning blade 62 is pressed against the photoreceptor 3, the deviation of the pressure in the longitudinal direction is large.

[0099] <<Surface layer>> The surface layer 623 has a tip ridge line portion 62c. The surface layer 623 has a domain with an average dispersion diameter of 0.1 μm or more and 5.0 μm or less in a region from the surface including the tip ridge line portion 62c to a depth of 100 μm. In the surface layer 623, the domain may be contained at a location other than the tip ridge line portion 62c. Note that the surface including the tip ridge line portion 62c corresponds to the aforementioned blade lower surface 62b (the surface facing the downstream side B in the rotation direction of the member to be cleaned).

[0100] The domain is a region having a polysiloxane structure. The polysiloxane structure is derived from, for example, a siloxane-based compound. The domain is formed, for example, by aggregation of a siloxane-based compound. At this time, the siloxane-based compound forming the domain may or may not be bonded to the matrix component.

[0101] The siloxane-based compound refers to a compound having a siloxane bond, and is, for example, silicone. Silicone exists in forms such as silicone oil, silicone resin, and silicone grease. The siloxane bond has the characteristic that the bond energy is larger than that of a carbon bond and can exist stably, and the siloxane-based compound has a small surface free energy and excellent releasability and lubricity.

[0102] As the siloxane-based compound, a compound composed of silicone is preferable, and the silicone described later can be used.

[0103] In the present embodiment, the average dispersion diameter of the domain is 0.1 μm or more and 5.0 μm or less, preferably 0.5 μm or more and 3.0 μm or less.

[0104] When the average dispersion diameter of the domain is 0.1 μm or more, since the dispersion diameter is large or it is difficult to be compatible, the effect of reducing the frictional force with the member to be cleaned (for example, the photoreceptor 3) is likely to appear, and the generation of curling at the tip of the blade can be suppressed. Further, when the average dispersion diameter of the domain is 5.0 μm or less, contamination due to the adhesion of the domain, which is an aggregation part of the siloxane-based compound, to the photoreceptor surface can be suppressed, and deterioration of image quality can be prevented.

[0105] Further, when the average dispersion diameter of the domain is 0.5 μm or more, curling at the tip of the blade can be more suppressed, and curling of the blade can be more suppressed even in a situation where images with less toner input to the blade are continuously output. Further, when the average dispersion diameter of the domain is 3.0 μm or less, since the dispersion diameter is smaller than that of a general toner particle size, it is less likely for the toner to adhere to the tip of the blade.

[0106] The method for calculating the average dispersion diameter can be obtained by measuring the dispersion diameters of 100 or more domains in a 100-μm region including an arbitrary tip ridge portion 62c and using the number average value. For example, the blade is cut at an arbitrary location to expose the cross section, and a 100-μm region including the tip ridge portion 62c is photographed with a laser microscope or SEM, and the dispersion diameter is measured from the image.

[0107] For the measurement of the dispersion diameter, it is also possible to calculate the dispersion diameter from the binary image using image analysis software such as ImagePro. At this time, it can be confirmed using EDS (Energy Dispersive X-ray Spectrometry) or the like that the domain of the observed image has a polysiloxane structure.

[0108] Note that the region from the surface including the tip ridge portion 62c to a depth of 100 μm is the region Y as shown in FIGS. 8 and 9. FIG. 8 is a diagram showing the position of the region Y, and FIG. 9 is an enlarged view of the region Y. In FIG. 9, the symbol S indicates a domain having a polysiloxane structure.

[0109] The average thickness of the surface layer 623 is not particularly limited and can be appropriately selected according to the purpose, but is preferably 30 μm or more and 800 μm or less, and more preferably 50 μm or more and 500 μm or less.

[0110] When the average thickness is 50 μm or more, even if it wears during long-term use, the surface exposed after wear also has a domain having a polysiloxane structure, and the portion in contact with the photoreceptor always has a domain having a polysiloxane structure even after wear, and a low friction coefficient can be maintained. Further, when the average thickness is 500 μm or less, deterioration of dimensional accuracy during processing due to the influence of the surface layer 623 having a domain having a polysiloxane structure can be further suppressed.

[0111] Here, the average film thickness of the surface layer 623 of the contact portion can be obtained by the arithmetic average value measured at 10 arbitrary locations of the surface layer 623 in the contact portion.

[0112] The method for measuring the thickness of the surface layer 623 of the contact portion is not particularly limited and can be appropriately selected according to the purpose. For example, a method of measuring a cut surface including the surface layer 623 of the contact portion using a microscope can be mentioned. Specifically, for example, the blade tip surface 62a is turned upward and observed with a microscope to measure the thickness of the surface layer 623.

[0113] The Martens hardness HM of the elastic member 624 measured under the condition of a load of 1000 μN from the surface layer 623 side at a position 20 μm from the tip edge portion 62c of the cleaning blade 62 is not particularly limited and can be appropriately selected according to the purpose. The Martens hardness HM (load: 1000 μN) of the elastic member 624 is from 0.3 N / mm 2 to 8.0 N / mm 2 or less is preferable, and from 0.5 N / mm 2 to 5.0 N / mm 2 or less is more preferable.

[0114] When the Martens hardness is 0.3 N / mm 2 or more, the tip edge portion 62c of the cleaning blade 62 is less likely to be deformed, and curling of the tip edge portion 62c can be further suppressed. When it is 8.0 N / mm 2 or less, chipping of the blade tip portion can be further suppressed.

[0115] The method for measuring the Martens hardness (HM) is as follows. For measuring the Martens hardness (HM), for example, a hardness tester (manufactured by Fischer Instruments, microhardness tester HM-2000) is used.

[0116] The Martens hardness is measured by pressing a Vickers indenter into the tip surface of the base material layer 622 with a force of 1.0 mN for 10 seconds, holding for 5 seconds, and pulling out with a force of 1.0 mN for 10 seconds. The measurement position shall be a position 20 μm away from the tip edge portion 62c of the lower surface S of the elastic member 624. As a method of measurement, the tip of the elastic member 624 is cut with a width of about 1 cm, fixed to a slide glass or the like with an adhesive or double-sided tape so that the lower surface S faces upward, and the above-described measurement position is measured.

[0117] The surface layer 623 of the elastic member 624 has, for example, a layer-forming resin component and a polysiloxane component that constitutes a domain. Specifically, in the surface layer 623, the polysiloxane component is dispersed in the layer-forming resin component.

[0118] In other words, the surface layer 623 has a sea-island structure in which the layer-forming resin component is the sea and the domains formed by the aggregation of the polysiloxane structure are the islands. The sea-island structure exists, for example, in a region up to a depth of 100 μm from the surface including at least the tip edge portion 62c. Note that the layer-forming resin component and the polysiloxane component may or may not be bonded by a chemical bond.

[0119] In the surface layer 623, the area ratio of the domains in the cross-section of the region Y is not particularly limited and can be appropriately selected according to the purpose. As the area ratio of the domains, in terms of being able to more effectively exhibit the effects of the present invention, it is preferably 0.1% or more and 40% or less, more preferably 0.5% or more and 30% or less, and even more preferably 1.0% or more and 20% or less.

[0120] The area ratio of the domains in the cross-section of the region can be obtained, for example, by the following method. The blade is cut at an arbitrary location to expose the cross-section, the region of 100 μm including the tip edge portion 62c is photographed with a laser microscope or SEM, and the area ratio occupied by the siloxane-based compound is calculated from the image. It can be obtained by calculating the area ratio from the binarized image using image analysis software such as ImagePro.

[0121] The surface layer 623 is obtained, for example, by curing the following second composition. The second composition is obtained by adding a curing agent composed of an active hydrogen compound to the following first composition in an emulsified state, for example.

[0122] [[First Composition]] The first composition contains at least one of the following component A and component B, and component C. A: NCO-terminated modified silicone prepolymer B: silicone oil C: NCO-terminated urethane prepolymer

[0123] [A: NCO-terminated modified silicone prepolymer] The NCO-terminated modified silicone prepolymer is a prepolymer having an isocyanate group at the terminal, which is obtained by reacting a modified silicone having at least one hydroxyl group at the terminal with a first polyisocyanate.

[0124] The modified silicone is a silicone having at least one hydroxyl group at the terminal, and commercially available products can be used. The modified silicone is selected from those capable of reacting with the first polyisocyanate to form a prepolymer having an NCO group at the terminal. Specifically, the modified silicone has a hydroxyl group or an amino group at the terminal, and from the viewpoint of stability, a hydroxyl group-modified silicone is preferred.

[0125] Examples of the modified silicone include KF-6000, KF-6001, KF-6002, KF-6003, X-22-176F, X-22-176DX, X-22-176GX-A (all commercially available products manufactured by Shin-Etsu Silicone Co., Ltd.). As for the type of terminal modification, there are single-terminal, double-terminal, side-chain, etc., but single-terminal modification is more preferred from the viewpoint of the efficiency of functioning as a surfactant as described later.

[0126] The first polyisocyanate is a compound that binds to the terminal of the modified silicone via a urethane bond and has an isocyanate group (NCO) at the terminal. Details of the first polyisocyanate will be described later.

[0127] The NCO-terminated modified silicone prepolymer is a silicone prepolymer having an NCO group at its terminal, obtained by the reaction of a modified silicone and a first polyisocyanate. The NCO-terminated modified silicone prepolymer can be obtained by mixing about twice the equivalent amount of the first polyisocyanate of the functional groups on the modified silicone side and heating with stirring.

[0128] [B: Silicone oil] The silicone oil is a silicone oil (organopolysiloxane) that is liquid at room temperature, and commercially available products can be used.

[0129] As the silicone oil, general polyorganosiloxanes can be used. Since the silicone oil is to be stably dispersed in the polyurethane / urea matrix, it is more preferable that the compatibility with the matrix is poor. Such a silicone oil is dispersed, for example, in an emulsified state in an NCO-terminated urethane prepolymer using an NCO-terminated modified silicone prepolymer as a surfactant.

[0130] Among the silicone oils, dimethyl silicone is more preferable. Dimethyl silicone oil is the most widely used silicone oil, and commercially available products from various companies can be used. In addition, during the above-mentioned emulsification, higher energy is required when the viscosity is high, so those having a viscosity of about 1 to 10,000 mPa·s / 25 °C are preferably used.

[0131] [C: NCO-terminated urethane prepolymer] The NCO-terminated urethane prepolymer is a prepolymer having an isocyanate group at its terminal, obtained by reacting a polyol and a second polyisocyanate.

[0132] The polyol is, for example, a polyol having a molecular weight of 500 to 4000, which is a so-called long-chain polyol used in the production of polyurethane resins. Polyester polyols, polyether polyols, polycarbonate polyols, etc. are preferably used.

[0133] The second polyisocyanate is a compound that reacts with the hydroxyl groups at the ends of the polyol and binds through urethane bonds, with the ends being isocyanate groups (NCO).

[0134] Examples of the polyisocyanate compounds used as the first polyisocyanate and the second polyisocyanate include m-phenylene diisocyanate, p-phenylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, naphthalene-1,4-diisocyanate, diphenylmethane-4,4'-diisocyanate, 3,3'-methoxy-4,4'-diphenyl diisocyanate, 3,3'-dimethyl diphenylmethane-4,4'-diisocyanate, xylylene-1,4-diisocyanate, 4,4'-diphenylpropane diisocyanate, hexamethylene diisocyanate, 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate, dicyclohexylmethane 4,4'-diisocyanate, cyclohexylene-1,2-diisocyanate, cyclohexylene-1,4-diisocyanate, and the like.

[0135] Here, it is preferable to select the first polyisocyanate and the second polyisocyanate such that the reactivity of the first polyisocyanate with respect to the curing agent is higher than that of the second polyisocyanate. The reactivity of the isocyanate group (R-NCO) increases as the electron-withdrawing property of the substituent R increases.

[0136] Specifically, the reactivity of aromatic polyisocyanates is greater than that of aliphatic polyisocyanates, and the reactivity decreases due to steric hindrance such as methyl groups in the side chains. These can be inferred from the following literature related to urethane.

[0137] · Hepburn, C.: Polyurethane Elastomers, Applied Science Publishers, (1982) · Saunders J. H., Frisch K. C. : Polyurethanes : Chemistry and technology, Part1. Chemistry, New York : Interscience Publishers, 170 (1962) · Handbook of Polyurethane Resins, edited by Keiji Iwata, Nikkan Kogyo Shimbun Ltd. (1987) · Curing Agents for Polyurethane Resin Coatings, Yoshiaki Takana, Journal of the Society of Color Material, 49 (1976)

[0138] Thus, generally, aromatic polyisocyanates have higher reactivity with curing agents than aliphatic or alicyclic polyisocyanates. For example, the first polyisocyanate may be an aromatic polyisocyanate, and the second polyisocyanate may be an aliphatic or alicyclic polyisocyanate. Also, both the first polyisocyanate and the second polyisocyanate may be aromatic polyisocyanates or aliphatic or alicyclic polyisocyanates.

[0139] Specifically, for example, an aromatic polyisocyanate can be used as the first polyisocyanate, and an aliphatic polyisocyanate can be used as the second polyisocyanate. Also, both the first polyisocyanate and the second polyisocyanate can be selected from aromatic polyisocyanates or aliphatic polyisocyanates.

[0140] Specifically, combinations such as xylylene diisocyanate (aliphatic high reactivity) as the first polyisocyanate and dicyclohexylmethane 4,4'-diisocyanate (aliphatic low reactivity) as the second polyisocyanate can be exemplified.

[0141] The NCO-terminated urethane prepolymer is the main component that forms the matrix of the cured urethane resin and can be appropriately synthesized or selected from commercially available products according to the desired physical properties. For example, it can be obtained by mixing a long-chain polyol such as a polyester polyol, a polyether polyol, or a polycarbonate polyol with a molecular weight of 500 to 4000 and a second polyisocyanate in an amount approximately twice the equivalent of the hydroxyl groups on the polyol side, and heating and stirring.

[0142] In addition, the NCO-terminated urethane prepolymer can be selected from commercially available products as long as it meets the requirements for the relative reactivity with the first polyisocyanate of the NCO-terminated modified silicone prepolymer.

[0143] The first composition contains at least one of component A and component B, as well as component C, and, for example, becomes an emulsified state by mixing.

[0144] That is, the NCO-terminated modified silicone prepolymer of component A acts as a surfactant and can hold the silicone oil of component B in an emulsified state in the NCO-terminated urethane prepolymer of component C. That is, the NCO-terminated modified silicone prepolymer coordinates around the particles of the silicone oil to form micelles, which become an emulsion dispersed in the NCO-terminated urethane prepolymer.

[0145] As described above, the first composition can be, for example, an emulsion in which the NCO-terminated modified silicone prepolymer and the silicone oil are dispersed in the NCO-terminated urethane prepolymer. As the dispersing device, general emulsifying devices such as a high-speed stirrer and a homogenizer can be used.

[0146] When the silicone oil is dispersed after the NCO-terminated modified silicone prepolymer is dispersed in the NCO-terminated urethane prepolymer, the first composition can be quickly produced as a uniform milky white dispersion.

[0147] <<Second Composition>> The second composition is obtained by adding a curing agent composed of an active hydrogen compound to the first composition in an emulsified state.

[0148] The curing agent is an active hydrogen-containing compound having reactivity with an NCO group. Specifically, it is a polyhydric hydroxy compound or a polyamine compound. When a polyhydric hydroxy compound is used as the curing agent, the matrix resin (layer-forming resin) becomes a polyurethane resin. When a polyamine is used as the curing agent, the matrix resin becomes a polyurethane urea resin.

[0149] Since it is effective to rapidly advance the reaction between the NCO-terminated silicone prepolymer serving as the shell and the curing agent, a curing agent containing a polyamine in an amount equal to or more than the NCO equivalent of the silicone prepolymer is preferably used.

[0150] The polyhydric hydroxy compound may be used together with a polyamine as a chain extender. In addition, known urethane curing catalysts (amines, organometallics) can also be used in combination to appropriately proceed the curing reaction.

[0151] Here, the polyhydric hydroxy compound is not particularly limited, but aliphatic polyhydric alcohols are preferably used.

[0152] Examples of the aliphatic polyhydric alcohol include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,4-cyclohexanedimethanol, 1,4-bis(hydroxyethoxy)benzene, 1,3-bis(hydroxyethoxy)benzene, and the like.

[0153] Examples of the polyamine compound include 4,4'-methylenebis(2-chloroaniline), diethyltoluenediamine, dimethylthiotoluenediamine, and the like.

[0154] The second composition becomes a cured polyurethane / urea resin by thermosetting with a predetermined mold or the like.

[0155] Here, since the second composition contains an NCO-terminated silicone prepolymer, an NCO-terminated urethane prepolymer, and a curing agent which is an active hydrogen-containing compound having reactivity with an NCO group, a cured polyurethane resin is obtained by reacting the NCO group with the curing agent.

[0156] Also, it is preferable to use, as the first polyisocyanate added to the terminal of the NCO-terminated silicone prepolymer and the second polyisocyanate added to the terminal of the NCO-terminated urethane prepolymer, those in which the reactivity with the curing agent is higher for the first polyisocyanate than for the second polyisocyanate.

[0157] In that case, the NCO-terminated silicone prepolymer forming the micelles reacts with the curing agent first, a core-shell structure is formed in which the silicone oil becomes the core and the cured product of the NCO-terminated silicone prepolymer becomes the shell.

[0158] That is, when the NCO-terminated silicone prepolymer forming the micelles reacts with the curing agent first, pseudo-capsules in which the silicone oil is immobilized in the micelles are generated. Then, since the NCO-terminated urethane prepolymer serving as the matrix reacts with the curing agent and cures, a cured urethane resin is obtained in a state where the core-shell structure is stably dispersed in the urethane / urea matrix.

[0159] The content of the siloxane-based compound in the cured urethane resin (surface layer 623) can be appropriately selected, but is preferably 0.1% by mass or more and 20% by mass or less, more preferably 1% by mass or more and 10% by mass or less, based on the cured product (surface layer 623).

[0160] When the content of the siloxane compound in the cured urethane resin is 0.1% by mass or more, the friction coefficient becomes small, and the curling of the tip ridge portion 62c can be suppressed. When the content of the siloxane compound in the cured urethane resin is 20% by mass or less, it is possible to suppress the component of the siloxane compound from moving to the member to be cleaned (for example, the photoreceptor 3) and contaminating the member to be cleaned.

[0161] In addition, when the siloxane compound is uniformly present throughout the surface layer 623, the content of the siloxane compound in the cured urethane resin may be determined by measuring at an arbitrary position of the surface layer 623. When the siloxane compound is unevenly distributed in the region up to a depth of 100 μm from the surface including the tip ridge portion 62c or in the vicinity thereof, the content of the siloxane compound in the cured urethane resin is the content in the region.

[0162] <<Base material layer>> The base material layer 622 of the elastic member 624 is not particularly limited with respect to its shape, size, material, structure, etc., and can be appropriately selected according to the purpose.

[0163] Examples of the shape of the base material layer 622 in the elastic member 624 include a flat plate shape, a strip shape, a sheet shape, etc. In addition, examples of the shape of the base material layer 622 include a shape having a pair of plate surfaces facing each other in the thickness direction of the base material layer 622, and two pairs of end surfaces orthogonal to the plate surfaces and facing each other in the in-plane direction of the plate surfaces.

[0164] In addition, the size of the base material layer 622 in the elastic member 624 can be appropriately selected according to, for example, the size of the member to be cleaned. As the material of the base material layer 622 in the elastic member 624, for example, polyurethane rubber, polyurethane elastomer, etc. are preferably used from the viewpoint of easily obtaining high elasticity.

[0165] The structure of the base material layer 622 in the elastic member 624 is not particularly limited and can be appropriately selected according to the purpose. For example, a single-layer structure composed of one type of material, a two-layer structure integrally formed by two different materials, a multi-layer structure integrally formed by several different materials, and the like can be mentioned.

[0166] In addition, when manufacturing the base material layer 622 in which two or more layers are laminated in the elastic member 624, raw materials with different mixing ratios can be continuously injected into the centrifugal molding die before each layer is completely cured, so that they can be integrally molded to prevent delamination between layers.

[0167] The manufacturing method of the base material layer 622 of the elastic member 624 is not particularly limited and can be appropriately selected according to the purpose.

[0168] For example, a polyurethane prepolymer is prepared using a polyol compound and a polyisocyanate compound, a curing agent and, if necessary, a curing catalyst are added to the polyurethane prepolymer, crosslinked in a predetermined mold, post-crosslinked in a furnace, then molded into a sheet shape by centrifugal molding, left at room temperature and aged, and then cut into a flat plate shape with a predetermined size, whereby the base material layer 622 of the elastic member 624 is manufactured.

[0169] The polyol compound is not particularly limited and can be appropriately selected according to the purpose. Examples of the polyol compound include high molecular weight polyol, low molecular weight polyol, and the like.

[0170] Examples of high molecular weight polyols include polyester polyols which are condensates of alkylene glycols and aliphatic dibasic acids; polyester-based polyols such as polyester polyols of alkylene glycol and adipic acid like ethylene adipate ester polyol, butylene adipate ester polyol, hexylene adipate ester polyol, ethylene propylene adipate ester polyol, ethylene butylene adipate ester polyol, ethylene neopentylene adipate ester polyol, etc.; polycaprolactone-based polyols such as polycaprolactone ester polyol obtained by ring-opening polymerization of caprolactone; polyether-based polyols such as poly(oxytetramethylene) glycol, poly(oxypropylene) glycol, etc. These may be used alone or in combination of two or more.

[0171] Examples of low molecular weight polyols include dihydric alcohols such as 1,4 - butanediol, ethylene glycol, neopentyl glycol, hydroquinone - bis(2 - hydroxyethyl) ether, 3,3´ - dichloro - 4,4´ - diaminodiphenylmethane, 4,4´ - diaminodiphenylmethane; trihydric or higher polyhydric alcohols such as 1,1,1 - trimethylolpropane, glycerin, 1,2,6 - hexanetriol, 1,2,4 - butanetriol, trimethylolethane, 1,1,1 - tris(hydroxyethoxymethyl)propane, diglycerin, pentaerythritol, etc. These may be used alone or in combination of two or more.

[0172] The polyisocyanate compound is not particularly limited and can be appropriately selected according to the purpose. Examples of the polyisocyanate compound include methylene diphenyl diisocyanate (MDI), tolylene diisocyanate (TDI), xylylene diisocyanate (XDI), naphthylene 1,5-diisocyanate (NDI), tetramethyl xylylene diisocyanate (TMXDI), isophorone diisocyanate (IPDI), hydrogenated xylylene diisocyanate (H6XDI), dicyclohexylmethane diisocyanate (H12MDI), hexamethylene diisocyanate (HDI), dimer acid diisocyanate (DDI), norbornene diisocyanate (NBDI), trimethylhexamethylene diisocyanate (TMDI), and the like. These may be used alone or in combination of two or more.

[0173] The curing catalyst is not particularly limited and can be appropriately selected according to the purpose. Examples thereof include 2-methylimidazole and 1,2-dimethylimidazole.

[0174] The content of the curing catalyst is not particularly limited and can be appropriately selected according to the purpose. Preferably, it is 0.01% by mass or more and 0.5% by mass or less, and more preferably 0.05% by mass or more and 0.3% by mass or less.

[0175] The JIS-A hardness of the base material layer 622 is not particularly limited and can be appropriately selected according to the purpose. Preferably, it is 60 degrees or more, and more preferably 65 degrees or more and 80 degrees or less. When the JIS-A hardness is 60 degrees or more, it is easy to obtain the blade line pressure, and the area of the contact portion with the photoreceptor is not easily expanded, so that cleaning failure is less likely to occur.

[0176] Here, the JIS-A hardness of the base material layer 622 can be measured using, for example, a hardness meter (manufactured by Kobunshi Keiki Co., Ltd., micro rubber hardness meter MD-1).

[0177] The resilience modulus of the base material layer 622 is not particularly limited and can be appropriately selected according to the purpose. Here, the resilience modulus of the base material layer 622 can be measured, for example, in accordance with the JIS K6255 standard, at 23°C, using a No. 221 resilience tester manufactured by Toyo Seiki Seisakusho.

[0178] The average thickness of the base material layer 622 is not particularly limited and can be appropriately selected according to the purpose, but is preferably 1.0 mm or more and 3.0 mm or less.

[0179] <Support member> The cleaning blade 62 preferably comprises a support member 621 and a flat elastic member 624 having one end connected to the support member 621 and a free end of a predetermined length at the other end. The cleaning blade 62 is arranged such that a contact portion including a tip ridge line portion, which is one end on the free end side of the elastic member 624, contacts the surface of the member to be cleaned along the longitudinal direction.

[0180] As the support member 621, as long as it is a member that supports the elastic member 624, its shape, size, material, etc. are not particularly limited and can be appropriately selected according to the purpose. Examples of the shape of the support member 621 include a flat plate shape, a strip shape, a sheet shape, etc. The size of the support member 621 can be appropriately selected according to the size of the member to be cleaned.

[0181] Examples of the material of the support member 621 include metal, plastic, ceramic, etc. Among these, a metal plate is preferable from the viewpoint of strength, and a steel plate such as stainless steel, an aluminum plate, and a phosphor bronze plate are particularly preferable.

[0182] <Photoconductor> Next, the photoconductor in the image forming apparatus of the present embodiment will be described. First, the layer structure of the photoconductor 3 will be described.

[0183] The photoreceptor 3 has a conductive support 91, a photosensitive layer 92, and a surface layer 93. The photosensitive layer 92 and the surface layer 93 are sequentially laminated on the conductive support 91. The surface layer 93 of the photoreceptor 3 has a binder resin and particles, and the Martens hardness is 150 N / mm 2 or more and less than 180 N / mm 2 and the elastic work rate is 35% or more and less than 45%.

[0184] As long as the photoreceptor 3 has a conductive support 91, a photosensitive layer 92, and a surface layer 93, other layers and the like may be arbitrarily combined.

[0185] Note that the photoreceptor 3 is an example of a photoreceptor (member to be cleaned) that constitutes a part of the image forming apparatus according to the present embodiment. Also, the photoreceptor 3 is an example of the photoreceptor according to the present embodiment.

[0186] FIG. 10 is an example of a photoreceptor in which a single-layer photosensitive layer 92 and a surface layer 93 are provided on a conductive support 91. FIG. 11 is an example of a photoreceptor in which a photosensitive layer 92 formed by laminating a charge generation layer 921 and a charge transport layer 922 on a conductive support 91 and a surface layer 93 are provided. Further, FIG. 12 is an example of a photoreceptor in which an undercoat layer 94 is provided on a conductive support 91, and a photosensitive layer 92 formed by laminating a charge generation layer 921 and a charge transport layer 922 and a surface layer 93 are provided.

[0187] As the conductive support 91, one having conductivity with a volume resistivity of 1010 Ω·cm or less can be used.

[0188] As such a conductive support, for example, a metal oxide coated on a film-shaped or cylindrical plastic or paper by vapor deposition or sputtering can be used. In this case, examples of the metal oxide include oxides of aluminum, nickel, chromium, copper, gold, silver, platinum, tin, indium, and the like.

[0189] In addition, as the conductive support 91, a tube obtained by forming a metal or a metal plate into a hollow tube by a method such as extrusion or drawing and then subjecting it to surface treatment such as cutting, superfinishing, and polishing can also be used. Examples of the metal in this case include aluminum, aluminum alloy, nickel, stainless steel, and the like.

[0190] Also, an endless nickel belt and an endless stainless steel belt disclosed in Japanese Patent Application Laid-Open No. 52-36016 can also be used as the conductive support 91.

[0191] In addition, a material obtained by dispersing conductive powder in an appropriate binder resin and coating it on the above support can also be used as the conductive support 91. Examples of the conductive powder in this case include carbon black, acetylene black, and metal powders such as aluminum, nickel, iron, nichrome, copper, zinc, and silver, or metal oxide powders such as conductive tin oxide and ITO (indium tin oxide).

[0192] Also, examples of the binder resin used simultaneously include thermoplastic resins, thermosetting resins, or photocurable resins such as 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, melamine resin, urethane resin, phenol resin, and alkyd resin.

[0193] Such a conductive layer can be provided by dispersing these conductive powder and binder resin in an appropriate solvent such as tetrahydrofuran, dichloromethane, methyl ethyl ketone, toluene, etc. and coating them.

[0194] Furthermore, a heat-shrinkable tube containing conductive powder in a material such as polyvinyl chloride, polypropylene, polyester, polystyrene, polyvinylidene chloride, polyethylene, chlorinated rubber, Teflon (registered trademark), etc. on a suitable cylindrical substrate and provided with a conductive layer can also be preferably used as the conductive support 91.

[0195] Next, the photosensitive layer 92 will be described. The photosensitive layer 92 may be a single layer or a laminate. First, the photosensitive layer 92 having a laminated structure composed of a charge generation layer 921 and a charge transport layer 922 shown in FIGS. 11 and 12 will be described.

[0196] The charge generation layer 921 is a layer mainly composed of a charge generating substance. Known charge generating substances can be used for the charge generation layer 921.

[0197] Examples of the charge generating substance include monoazo pigments, disazo pigments, trisazo pigments, perylene-based pigments, perinone-based pigments, quinacridone-based pigments, quinone-based condensed polycyclic compounds, squaric acid-based dyes, other phthalocyanine-based pigments, naphthalocyanine-based pigments, azulenium salt-based dyes, etc. These charge generating substances may be used alone or in combination of two or more.

[0198] In this embodiment, an azo pigment and / or a phthalocyanine pigment is preferably used as the charge generating substance. Among these, the azo pigment represented by the following [Chemical Formula 1], or titanyl phthalocyanine (particularly titanyl phthalocyanine having a maximum diffraction peak at at least 27.2° as a diffraction peak (±0.2°) of the Bragg angle 2θ with respect to the characteristic X-ray of CuKα (wavelength 1.514 Å)) is more preferably used.

[0199]

Chemical Formula

[0200] The charge generating layer 921 is formed by dispersing the charge generating material, if necessary together with a binder resin, in a suitable solvent using a ball mill, attritor, sand mill, ultrasonic wave, or the like, applying the dispersion to the conductive support 91, and drying it.

[0201] Examples of binder resins that can be used in the charge generating layer 921 as needed include polyamide, polyurethane, epoxy resin, polyketone, polycarbonate, silicone resin, acrylic resin, polyvinyl butyral, polyvinyl formal, polyvinyl ketone, polystyrene, polysulfone, poly-N-vinylcarbazole, polyacrylamide, polyvinyl benzal, polyester, phenoxy resin, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyphenylene oxide, polyamide, polyvinylpyridine, cellulose-based resin, casein, polyvinyl alcohol, and polyvinylpyrrolidone.

[0202] The amount of binder resin is not particularly limited, and can be 0 to 500% by mass, and preferably 10 to 300% by mass, relative to 100% by mass of the charge generating substance.

[0203] 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, etc. Among these, ketone-based solvents, ester-based solvents, and ether-based solvents are preferably used as the solvent.

[0204] The coating method for the coating liquid may be dip coating, spray coating, bead coating, nozzle coating, spinner coating, ring coating, or the like.

[0205] The thickness of the charge generating layer 921 can be set to about 0.01 to 5 μm, and preferably 0.1 to 2 μm.

[0206] The charge transport layer 922 can be formed by dissolving or dispersing a charge transport material and a binder resin in a suitable solvent, applying this onto the charge generation layer 921, and drying. Also, a plasticizer, a leveling agent, an antioxidant, etc. may be added as necessary.

[0207] There are an electron transport material and a hole transport material as the charge transport materials.

[0208] Examples of the electron transport material include electron-accepting materials such as chloranil, bromanil, tetracyanoethylene, tetracyanoquinodimethane, 2,4,7-trinitro-9-fluorenone, 2,4,5,7-tetranitro-9-fluorenone, 2,4,5,7-tetranitroxanthone, 2,4,8-trinitrothioxanthone, 2,6,8-trinitro-4H-inden[1,2-b]thiophen-4-one, 1,3,7-trinitrodibenzothiophene-5,5-dioxide, and benzoquinone derivatives.

[0209] Examples of the hole transport material include poly-N-vinylcarbazole and its derivatives, poly-γ-carbazolylethyl glutamate and its derivatives, pyrene-formaldehyde condensates and their derivatives, 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, pyrazoline derivatives, divinylbenzene derivatives, hydrazone derivatives, indene derivatives, butadiene derivatives, pyrene derivatives, etc., bisstilbene derivatives, enamine derivatives, etc.

[0210] These charge transport materials may be used alone or in combination of two or more.

[0211] Examples of binder resins include thermoplastic resins or thermosetting resins such as polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyvinylidene 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, phenolic resin, and alkyd resin.

[0212] The amount of the charge transport material is not particularly limited, and can be 20 to 300% by mass, preferably 40 to 150% by mass, relative to 100% by mass of the binder resin.

[0213] The thickness of the charge transport layer 922 is not particularly limited, but is preferably 30 μm or less from the viewpoint of resolution or responsiveness. The lower limit of the thickness of the charge transport layer 922 varies depending on the system used (e.g., charging potential, etc.), but is preferably 5 μm or more.

[0214] Examples of the solvent used here include tetrahydrofuran, dioxane, toluene, dichloromethane, monochlorobenzene, dichloroethane, cyclohexanone, methyl ethyl ketone, and acetone.

[0215] In the photoreceptor of this embodiment, a plasticizer or a leveling agent may be added to the charge transport layer 922. As the plasticizer, dibutyl phthalate, dioctyl phthalate, or the like, which is used as a plasticizer for general resins, can be used as is, and the amount used is about 0 to 30% by mass of the binder resin.

[0216] As the leveling agent, for example, silicone oils such as dimethyl silicone oil and methylphenyl silicone oil, polymers having a perfluoroalkyl group in the side chain, oligomers, etc. are used, and the appropriate amount used is 0 to 1% by mass based on the binder resin.

[0217] Next, the case where the photosensitive layer 92 has a single-layer structure shown in FIG. 10 will be described.

[0218] As the photosensitive layer 92, a photoreceptor in which the above-described charge generating substance is dispersed in a binder resin can be used. The single-layer photosensitive layer 92 is formed by dissolving or dispersing a charge generating substance, a charge transporting substance, and a binder resin in an appropriate solvent, and then coating and drying this solution.

[0219] Also, if necessary, a plasticizer, a leveling agent, an antioxidant, etc. can be added to the photosensitive layer 92. As the binder resin, in addition to using the binder resin listed in the charge transport layer 922 above as it is, the binder resin listed in the charge generation layer may be mixed and used.

[0220] With respect to 100% by mass of the binder resin, the amount of the charge generating substance is preferably 5 to 40% by mass, and the amount of the charge transporting substance is preferably 0 to 190% by mass, more preferably 50 to 150% by mass.

[0221] The single-layer photosensitive layer 92 can be formed by coating a coating liquid obtained by dispersing a charge generating substance, a binder resin, and a solvent such as tetrahydrofuran, dioxane, dichloroethane, cyclohexane, etc. with a dispersing machine, etc. using a dipping coating method, spray coating, bead coating, etc.

[0222] The film thickness of the single-layer photosensitive layer 92 is appropriately about 5 to 35 μm.

[0223] 12, the photoreceptor of this embodiment can have an undercoat layer 94 between the conductive support 91 and the photosensitive layer 92. The undercoat layer 94 is usually composed mainly of a resin, and considering that the photosensitive layer 92 is applied onto the undercoat layer 94 using a solvent, it is desirable that the resin be highly resistant to ordinary organic solvents.

[0224] 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; and curable resins that form a three-dimensional network structure, such as polyurethane, melamine resin, phenolic resin, alkyd-melamine resin, and epoxy resin.

[0225] Furthermore, the undercoat layer 94 may contain fine powder pigments of metal oxides such as titanium oxide, silica, alumina, zirconium oxide, tin oxide, and indium oxide to prevent moire and reduce residual potential.

[0226] The undercoat layer 94 can be formed using an appropriate solvent and coating method, as in the case of the photosensitive layer 92. Furthermore, in this embodiment, the undercoat layer 94 can also be formed using a silane coupling agent, a titanium coupling agent, a chromium coupling agent, or the like.

[0227] Alternatively, the undercoat layer 94 may be formed by anodizing AlO or by vacuum thin film deposition of an organic material such as polyparaxylylene (parylene) or an inorganic material such as SiO, SnO, TiO, ITO, or CeO. Other known materials may also be used for the undercoat layer 94.

[0228] The thickness of the undercoat layer 94 is not particularly limited, but is preferably 0 to 5 μm.

[0229] The photoreceptor 3 in this embodiment has a binder resin and particles on a single-layer or multi-layer photosensitive layer 92, and has a Martens hardness of 150 N / mm 2 More than 180N / mm2 A surface layer 93 having a Martens hardness of less than 180 N / mm² and an elastic work ratio of 35% or more and less than 45% is laminated.

[0230] The surface layer 93 of the photoreceptor 3 used in this embodiment is formed by applying a coating solution containing at least a binder resin and particles, and has a Martens hardness of 150 N / mm² or more and less than 180 N / mm², and an elastic work ratio of 35% or more and less than 45%. 2 or more and less than 180 N / mm² 2 and one having an elastic work ratio of 35% or more and less than 45% is used.

[0231] The surface layer 93 is composed of at least particles and a binder resin. As the binder resin, for example, thermoplastic resins such as polyarylate resin and polycarbonate resin, and crosslinked resins such as urethane resin and phenol resin are used.

[0232] As the particles, organic particles and inorganic particles are used.

[0233] Examples of the organic particles include fluorine-containing resin particles and diamond particles.

[0234] Examples of the inorganic particles include metal powders such as copper, tin, aluminum, and indium, oxides such as silicon oxide, silica, tin oxide, zinc oxide, titanium oxide, indium oxide, antimony oxide, bismuth oxide, tin-doped indium oxide, and antimony-doped tin oxide, and inorganic materials such as potassium titanate. Among these inorganic particles, oxides are preferable, and silicon oxide, aluminum oxide, titanium oxide, etc. are more preferable.

[0235] The higher the concentration of the inorganic particles in the surface layer 93, the more preferable it is in terms of higher wear resistance. However, if it is too high, the residual potential may increase and the light transmittance of the writing light of the protective layer may decrease, resulting in side effects. Therefore, the concentration of the inorganic particles in the surface layer 93 is about 50% by mass or less based on the total solid content, preferably 30% by weight or less. The lower limit value of the concentration of the inorganic particles in the surface layer 93 is not particularly limited, but is usually 5% by weight.

[0236] Also, these inorganic particles can be surface-treated with at least one kind of surface treatment agent. Further, surface-treating the inorganic particles in this way is preferable in terms of the dispersibility of the inorganic particles.

[0237] A decrease in the dispersibility of inorganic particles not only causes an increase in the residual potential, but also leads to a decrease in the transparency of the coating film, the occurrence of coating film defects, and further a decrease in the wear resistance. Therefore, it may develop into a major problem that hinders high durability or high image quality.

[0238] As the surface treatment agent, conventionally used surface treatment agents can be used, but surface treatment agents that can maintain the insulating properties of the inorganic particles are preferable.

[0239] Examples of such surface treatment agents include titanate-based coupling agents, aluminum-based coupling agents, zirconate-based coupling agents, higher fatty acids, etc., or a mixed treatment of these with a silane coupling agent, or Al2O3, TiO2, ZrO2, silicone, aluminum stearate, etc., or a mixed treatment thereof is more preferable in terms of the dispersibility of the inorganic particles and image blurring.

[0240] Treatment with a silane coupling agent strengthens the influence of image blurring, but in some cases, the influence can be suppressed by performing a mixed treatment of the above surface treatment agent and the silane coupling agent.

[0241] The amount of surface treatment varies depending on the average primary particle diameter of the inorganic particles used, but about 3 to 30 wt% is an appropriate amount, and preferably about 5 to 20 wt%. If the amount of surface treatment is too small, the dispersing effect of the inorganic particles cannot be obtained, and if it is too large, there is a possibility of causing a significant increase in the residual potential.

[0242] These inorganic particles may be used alone or in combination of two or more.

[0243] The film thickness of the surface layer 93 is not particularly limited, but is preferably in the range of 1.0 to 8.0 μm.

[0244] Photoconductors that are used repeatedly over long periods of time are mechanically durable and resistant to wear. However, in actual machines, ozone and NOx gases are generated from charging components and other elements, and these gases adhere to the surface of the photoconductor. The presence of these deposits can cause image deletion. To prevent this image deletion, the photosensitive layer 92 must be worn at a certain rate or faster.

[0245] Therefore, when long-term repeated use is taken into consideration, it is preferable that the surface layer 93 has a film thickness of at least 1.0 μm or more.

[0246] Furthermore, if the thickness of the surface layer 93 is greater than 8.0 μm, the residual potential may increase and the reproducibility of fine dots may decrease. These inorganic particles can be dispersed using an appropriate dispersing machine.

[0247] Furthermore, in terms of the transmittance of the surface layer 93, the average particle size of the inorganic particles in the dispersion is preferably 1 μm or less, and more preferably 0.5 μm or less.

[0248] For example, dip coating, ring coating, spray coating, etc. can be used as a method for providing the surface layer 93 on the photosensitive layer 92. Among these, a common method for forming the surface layer 93 is the spray coating method, in which paint is ejected from a nozzle with a minute opening, atomized, and the resulting minute droplets are deposited on the photosensitive layer 92 to form a coating film.

[0249] Examples of the solvent used here include tetrahydrofuran, dioxane, toluene, dichloromethane, monochlorobenzene, dichloroethane, cyclohexanone, methyl ethyl ketone, and acetone.

[0250] The surface layer 93 may contain a charge transport material to reduce residual potential and improve response. The charge transport material may be the same as that used in the charge transport layer described above.

[0251] When a low molecular weight charge transport material is used as the charge transport material, the surface layer 93 may have a concentration gradient.

[0252] A polymer charge transport material that functions as both a charge transport material and a binder resin is also preferably used for the surface layer 93. The surface layer 93 made of such a polymer charge transport material has excellent abrasion resistance.

[0253] Although known materials can be used as the polymer charge transport material, it is preferable to use at least one polymer selected from the group consisting of polycarbonate, polyurethane, polyester, and polyether. Among these, polycarbonate containing a triarylamine structure in the main chain and / or side chain is preferable.

[0254] The hardness of the surface layer 93 of the photoreceptor 3 is Martens hardness 150 N / mm 2 More than 180N / mm 2 The Martens hardness and the elastic power (We / Wt value) are measured under the following conditions.

[0255] Evaluation device: Fisherscope H-100 Test method: Repeated loading and unloading (1 time) test Indenter: Micro Vickers indenter Maximum load: 9.8mN Loading (unloading) time: 30 seconds Holding time: 5sec

[0256] Martens hardness 150N / mm 2 If the pressure is less than 180N / mm, the toner may stick to the surface of the photoconductor. 2 In the above cases, local wear of the cleaning blade used in this embodiment increases.

[0257] Also, when the elastic work rate (We / Wt value) is less than 35%, the wear speed of the photoreceptor changes, such as when the image area ratio changes in the axial direction of the photoreceptor, and wear unevenness is likely to occur. When it is 45% or more, the cleaning performance may decrease when cleaning the toner remaining on the photoreceptor with the cleaning blade 62.

[0258] Therefore, the hardness and elastic work rate are controlled by the addition amount of inorganic particles and the resin type. Resins such as polycarbonate and polyarylate improve the hardness and elastic work rate by incorporating a rigid structure into the resin skeleton. Also, by adopting a polymer charge transport material, the hardness and elastic work rate are improved.

[0259] The friction coefficient of the photoreceptor 3 is not particularly limited and can be appropriately selected according to the purpose. Preferably, the surface friction coefficient measured by the Euler belt method is 0.2 or more. Here, the Euler belt method is a method for measuring the friction coefficient between paper and the photoreceptor, and is described, for example, in paragraph 0023 of JP-A-2010-134398. Specifically, the friction coefficient of the photoreceptor surface is measured using the measuring device shown in FIG. 13.

[0260] In the measuring device based on the Euler belt method of FIG. 13, the belt 140 is composed of a piece of medium-thick high-quality paper (#6200 paper (T mesh)) of 30 mm × 250 mm. Hooks 140a and 140b are attached to both ends of the belt 140. A load (for example, a load of 100 g weight) 141 is hung on the hook 140a, and a digital force gauge 142 is installed on the hook 140b. Then, the cylindrical photoreceptor 143 is fixed by the support base 144.

[0261] In the measuring device of FIG. 13, the digital force gauge 42 is pulled in the 90° direction, the value F at the time when the belt 40 starts to move is read, and substituted into the following formula (1) to calculate the photoreceptor surface friction coefficient μ.

[0262] μ = ln(F / W) / (π / 2) ··· (1) However, F: The value indicated by the digital force gauge W: Load (100g in this experiment) π: Pi is.

[0263] As described above, the image forming apparatus of this embodiment has a Martens hardness of 150 N / mm 2 More than 180N / mm 2 and a cleaning blade 62 having a domain having a polysiloxane structure with an average dispersion diameter of 0.1 μm or more and 5.0 μm or less in a region from the surface including the tip ridge portion 62c of the elastic member 624 to a depth of 100 μm.

[0264] With this configuration, the image forming apparatus of this embodiment can suppress abnormal wear of the photosensitive member and cleaning blade and curling of the cleaning blade edge. Also, the image forming apparatus of this embodiment can improve the cleaning blade edge's ability to follow the photosensitive member over a long period of time, thereby maintaining good cleaning performance.

[0265] In addition, as described above, in the image forming apparatus of this embodiment, the cleaning blade 62 has a Martens hardness of 0.3 N / mm2 of the elastic member 624 measured under a load of 1000 μN from the side of the surface layer 623 at a position 20 μm away from the edge 62c toward the inside of the surface. 2 More than 8.0N / mm 2 The following is the result.

[0266] With this configuration, in the image forming apparatus of this embodiment, the leading edge 62c of the cleaning blade 62 is less likely to deform, and the leading edge 62c is more likely to be prevented from curling up, while chipping of the blade leading edge can be more effectively prevented.

[0267] Furthermore, as described above, the image forming apparatus of this embodiment has a lubricant application device 10 (lubricant application unit) that applies a lubricant to the surface of the photosensitive member 3, thereby enabling the surface of the photosensitive member 3 to maintain a low coefficient of friction even when worn.

[0268] Furthermore, in the image forming apparatus of the present embodiment, as described above, by setting the coefficient of friction on the surface of the photoreceptor 3 measured by the Euler belt method to 0.2 or more, while suppressing the curling of the tip ridge line portion 62c of the cleaning blade 62, it becomes easier to obtain the blade line pressure. Therefore, in the image forming apparatus of the present embodiment, it is less likely to cause cleaning failures.

[0269] As described above, the cleaning blade of the present embodiment has a domain having a polysiloxane structure with an average dispersion diameter of 0.1 μm or more and 5.0 μm or less in a region from the surface including the tip ridge line portion 62c of the elastic member 624 to a depth of 100 μm. With such a configuration, the cleaning blade of the present embodiment can obtain the same effects as those obtained by the cleaning blade constituting a part of the above-described image forming apparatus.

[0270] Specifically, the cleaning blade of the present embodiment can suppress abnormal wear of the photoreceptor and the cleaning blade and the occurrence of curling of the tip ridge line portion of the cleaning blade. Further, the cleaning blade of the present embodiment can maintain good followability of the tip ridge line portion of the cleaning blade to the photoreceptor over a long period of time and maintain good cleaning performance.

[0271] Also, as described above, the cleaning blade of the present embodiment has a Martens hardness of the elastic member 624 measured under the condition of a load of 1000 μN from the side of the surface layer 623 at a position 20 μm away from the tip ridge line portion 62c to the inside of the surface. 2 is 0.3 N / mm 2 or more and 8.0 N / mm

[0272] Specifically, in the cleaning blade of this embodiment, the leading edge 62c of the cleaning blade 62 is less likely to deform, and thus the leading edge 62c is more effectively prevented from curling up, while chipping of the blade leading edge can be more effectively prevented.

[0273] As described above, the photoreceptor of this embodiment has a surface layer 93 with a Martens hardness of 150 N / mm 2 More than 180N / mm 2 and the elastic power is 35% or more and less than 45%. With this configuration, the photoreceptor of this embodiment can directly obtain the effects obtained with the photoreceptor that constitutes a part of the image forming apparatus described above.

[0274] Specifically, the photoreceptor of this embodiment can suppress abnormal wear of the photoreceptor and cleaning blade and curling of the cleaning blade edge. Furthermore, the photoreceptor of this embodiment can improve the ability of the cleaning blade edge to follow the photoreceptor, thereby maintaining good cleaning performance over a long period of time.

[0275] Furthermore, as described above, the photoreceptor of this embodiment has a surface friction coefficient of 0.2 or more measured by the Euler belt method, thereby achieving the same effects as those of the photoreceptor constituting a part of the image forming apparatus described above. Specifically, the photoreceptor of this embodiment makes it easier to obtain blade linear pressure while suppressing curling of the leading edge portion 62c of the cleaning blade 62. [Example]

[0276] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples. In the following, "parts" and "%" are by mass unless otherwise specified.

[0277] <Test specimen (elastic member)> As a test piece, an elastic member having a base material layer and a surface layer was produced. The base material layer of the elastic member was produced by centrifugal molding of the following urethane rubber with a JIS-A hardness, a 23°C resilience rate, and a Martens hardness (HM). JIS-A hardness: 75° 23°C resilience rate: 45% Martens hardness (HM): 0.9 N / mm 2

[0278] The measurement methods for each of the JIS-A hardness, the 23°C resilience rate, and the Martens hardness (HM) are shown below.

[0279] [[Base material layer's JIS-A hardness]] The JIS-A hardness on the lower surface side of the base material layer of the elastic member was measured at 23°C in accordance with JIS K6253 using a hardness meter (manufactured by Kobunshi Keiki Co., Ltd., Micro Rubber Hardness Meter MD-1).

[0280] [[Base material layer's resilience rate]] The resilience rate of the base material layer of the elastic member was measured at 23°C in accordance with JIS K6255 using a resilience tester (manufactured by Toyo Seiki Seisakusho, No. 221 Resilience Tester). As the sample, two sheets of 2 mm thick sheets were overlapped so that the thickness was 4 mm or more.

[0281] [[Base material layer's Martens hardness]] The Martens hardness of the base material layer of the elastic member was measured using the above-mentioned hardness meter (manufactured by Fisher Instruments, Micro Hardness Meter HM-2000).

[0282] [[Surface layer formation]] The materials used in the curable composition for forming the surface layer are shown below.

[0283] [[Isocyanate]] · MDI (4,4'-diphenylmethane diisocyanate): manufactured by Tosoh Corporation, Millionate (registered trademark) MT · Hydrogenated MDI (dicyclohexylmethane 4,4'-diisocyanate): manufactured by Tokyo Chemical Industry Co., Ltd. ·TDI (2,4-Tolylene Diisocyanate): Manufactured by Tosoh Corporation, Coronate (registered trademark) T-100 ·TODI (o-Tolylene Diisocyanate): Manufactured by Nippon Soda Co., Ltd.

[0284] [Polyol] ·PTMG (Polytetramethylene Ether Glycol): Manufactured by Mitsubishi Chemical Corporation, PTMG1000 ·PCL (Polycaprolactone Diol): Manufactured by Daicel Corporation, Placcel (registered trademark) 220

[0285] [Hardening Agent] ·DETDA (Diethyltoluenediamine): Manufactured by Mitsui Chemicals Fine Inc., Ethacure (registered trademark) 100 ·DMTDA (Dimethylthiotoluenediamine): Mitsui Chemicals Fine, Ethacure (registered trademark) 300 ·BD (1,4-Butanediol): Manufactured by Mitsubishi Chemical Corporation ·TMP (Trimethylolpropane): Manufactured by Mitsubishi Gas Chemical Company

[0286] [Siloxane-based Compound] ·Monofunctional Carbinol-modified Silicone Oil: Manufactured by Shin-Etsu Silicone Co., Ltd., X-22-176DX ·Bifunctional Carbinol-modified Silicone Oil: Manufactured by Shin-Etsu Silicone Co., Ltd., KF6000 ·Dimethyl Silicone Oil: Manufactured by Shin-Etsu Silicone Co., Ltd., KF96-3000cs

[0287] [Synthesis of NCO-terminated Silicone Prepolymer (Prepolymer A)] As shown in Table 1 below, the isocyanate and the modified silicone oil were mixed so as to obtain the desired NCO%, and reacted at 60 °C for 90 minutes to prepare NCO-terminated silicone prepolymers A1 and A2.

[0288]

Table 1

[0289] In Table 1, "176-DX" indicates X-22-176DX.

[0290] [Synthesis of NCO-terminated urethane prepolymer (prepolymer B)] As shown in Table 2 below, isocyanate and polyol were mixed to achieve the desired NCO % and reacted with 0.01 g of a tin catalyst (dibutyltin dilaurate) at 80°C for 90 minutes to prepare NCO-terminated urethane prepolymers B1 to B3.

[0291] [Table 2]

[0292] In Table 2, "PCL220" represents Placcel 220.

[0293] [Preparation of hardener] As shown in Table 3 below, curing agents 1 to 3 were prepared.

[0294] [Table 3]

[0295] <Production of cleaning blade 1> Prepolymer A1, prepolymer B, and silicone oil were mixed in the formulation shown in Table 4 and stirred with a homogenizer (15,000 rpm) to obtain a first composition. The stirring conditions are shown in Table 4.

[0296] The first composition, in which silicone oil was emulsified and heated to 80°C, was mixed with curing agent 1, and the mixture was allowed to react for 30 minutes in a centrifugal drum heated to 125°C (curing temperature) to form a base layer, yielding a rubber sheet with a surface layer. The mixture of the first composition and curing agent was adjusted so that the R value (NCO group / OH group molar ratio) was 0.925.

[0297] A part of the obtained rubber sheet was cut out into a strip shape so that it could be mounted on a color printer (Ricoh Pro C9110, manufactured by Ricoh Company, Ltd.), and fixed to a sheet metal holder (support member) with an adhesive. In this way, the cleaning blade 1 having an elastic member with a surface layer formed on the contact portion was produced. At this time, the rubber sheet was placed with the surface layer facing downward and cut from the base material layer side so that the razor blade would hit it.

[0298] <Creation of Cleaning Blades 2 to 9> In the production of the cleaning blade 1, except that the first composition, curing agent, homogenizer time, and curing temperature were changed to those shown in Table 4 for the first composition, curing agent, homogenizer time, and curing temperature, the cleaning blade was produced in the same manner as the cleaning blade 1.

[0299]

Table 4

[0300] In Table 4, KF96 indicates KF96-3000cs.

[0301] For the produced cleaning blades 1 to 9, the average dispersion diameter of the domain and the Martens hardness were measured as follows. The results are shown in Table 5.

[0302]

Table 5

[0303] <Average Dispersion Diameter of Domains Having a Polysiloxane Structure> The produced elastic member was cut into rings on a plane perpendicular to the longitudinal direction, with this cross-section facing upward, and a 100-μm region including the tip ridge line portion was observed with a laser microscope (OLS4100, manufactured by Olympus Corporation). As a method of cutting the elastic member into rings, a razor was used to cut perpendicularly to the longitudinal direction of the elastic member so that the thickness in the longitudinal direction of the elastic member would be 3 mm. At that time, when using a vertical slicer, the cross-section can be cut more neatly.

[0304] For the observed images, the average dispersion diameter of the domains was measured using ImagePro ver5.1. The length of the line segment connecting two points on the outer periphery of the domain observed in the cross-section and passing through the center of gravity of the domain was measured in steps of two degrees. The average value of the measured line segment lengths was taken as the dispersion diameter of the domain. The dispersion diameters of 100 to 200 domains were measured, and the number average value was calculated and taken as the average dispersion diameter.

[0305] <Martens hardness of the cleaning blade> The Martens hardness (HM) of the cleaning blade on the lower surface of the cleaning blade was measured using a hardness tester (Fisher Instruments, microhardness tester HM-2000), with a Vickers indenter pressed in with a force of 1.0 mN for 10 seconds, held for 5 seconds, and pulled out with a force of 1.0 mN for 10 seconds.

[0306] The measurement position was set at a position 20 μm from the leading edge ridge of the blade lower surface, and the measurement was performed with the Vickers indenter in contact with the surface layer. Note that the measurement locations were positions excluding the 2 cm portions at both ends.

[0307] <Assembly of the image forming apparatus> The above-prepared blades 1 to 9 were attached to a color printer (Ricoh, RICOH Pro C9110) to assemble an image forming apparatus. The cleaning blade was attached to the image forming apparatus so that the line pressure was 20 g / cm and the cleaning angle was 79°.

[0308] <Fabrication of the photoreceptor> Photoreceptors 1 to 8 were fabricated under the following conditions.

[0309] <Photoreceptor 1> [Support] An aluminum support (outer diameter 100 mmΦ) bare tube was used.

[0310] [Undercoat layer] The undercoat layer coating liquid was applied by dipping onto the support so that the film thickness after drying would be 3.5 μm, thereby forming an undercoat layer.

[0311] (Undercoat layer coating liquid) Alkyd resin: Beccosol (registered trademark) 1307-60-EL, manufactured by Dainippon Ink and Chemicals, Inc. Melamine resin: Super Beckamin G-821-60 manufactured by Dainippon Ink and Chemicals, Inc. Titanium oxide: Ishihara Sangyo Co., Ltd., CR-EL Methyl ethyl ketone (mass ratio): alkyd resin / melamine resin / titanium oxide / methyl ethyl ketone = 3 / 2 / 20 / 100

[0312] [Charge generation layer] A charge generating layer coating liquid containing titanyl dicyanine was applied onto the undercoat layer by dip coating, and then dried by heating to form a charge generating layer having a thickness of 0.2 μm.

[0313] (Charge generation layer coating liquid) Titanyl dicyanine Polyvinyl butyral (XYHL:UCC) 2-Butanone (mass ratio): titanyl cyclohexyl cyanine / polyvinyl butyral / 2-butanone = 8 / 5 / 400

[0314] FIG. 14 shows an example of the powder X-ray diffraction spectrum of the titanyl phthalocyanine used.

[0315] [Charge transport layer] The following coating liquid for a charge transport layer was applied onto the charge generating layer by dip coating, and then dried by heating to form a charge transport layer having a thickness of 25 μm.

[0316] (Charge transport layer coating liquid) Charge transport layer coating liquid: Bisphenol Z type polycarbonate Charge transport material of the following formula [Chemical formula 2] [ka] Tetrahydrofuran (mass ratio): polycarbonate / charge transport material / tetrahydrofuran = 1 / 1 / 10

[0317] [Surface layer] The surface layer coating solution 1 described below was spray-coated onto the charge transport layer, and the coating was dried to the touch for 5 minutes. The coating was then dried at 130°C for 20 minutes to form a 5 μm surface layer. Photoreceptor 1 was thus obtained.

[0318] (Surface layer coating liquid 1) 8 parts of the charge transport material of the following formula [3] [ka] Bisphenol Z-type polycarbonate binder resin (Teijin Chemicals, Panlite (registered trademark) TS-2040): 2 parts Bisphenol Z-type polycarbonate binder resin (Teijin Chemicals, Panlite (registered trademark) TS-2050): 8 parts Additive (BASF Japan, Irganox 1076): 1.5 parts Silica particles (KMPX100, manufactured by Shin-Etsu Chemical Co., Ltd.): 2 parts Tetrahydrofuran: 400 parts

[0319] <Photoconductor 2> Photoreceptor 2 was obtained in the same manner as for photoreceptor 1, except that surface layer coating liquid 2 below was used.

[0320] (Surface layer coating liquid 2) Charge transport material of the above formula (3): 7.5 parts Bisphenol Z-type polycarbonate binder resin (Teijin Chemicals, Panlite (registered trademark) TS-2040): 2 parts Bisphenol Z-type polycarbonate binder resin (Teijin Chemicals, Panlite (registered trademark) TS-2050): 8 parts Additive (BASF Japan, Irganox 1076): 1 part Fluorine particles (Mitsui DuPont Fluorochemicals, MPE-056): 2 parts · Tetrahydrofuran: 400 parts

[0321] <Photoconductor 3> A photoconductor 3 was obtained in the same manner as the photoconductor 1, except that the following surface layer coating liquid 3 was used.

[0322] (Surface layer coating liquid 3) · Charge transport material of the above [Chemical formula 3]: 8 parts · Binder resin of bisphenol Z type polycarbonate (manufactured by Teijin Chemicals, Panlite (registered trademark) TS-2050): 5 parts · Binder resin of bisphenol Z type polycarbonate (manufactured by Teijin Chemicals, Panlite (registered trademark) TS-2080): 5 parts · Additive (manufactured by BASF Japan, Irganox1076): 1 part · Alumina particles (AA03: manufactured by Sumitomo Chemical): 2 parts · Tetrahydrofuran: 500 parts

[0323] <Photoconductor 4> A photoconductor 4 was obtained in the same manner as the photoconductor 1, except that the following surface layer coating liquid 4 was used.

[0324] (Surface layer coating liquid 4) · Charge transport material of the above [Chemical formula 3]: 7.5 parts · Binder resin of bisphenol Z type polycarbonate (manufactured by Teijin Chemicals, Panlite (registered trademark) TS-2050): 5 parts · Binder resin of bisphenol Z type polycarbonate (manufactured by Teijin Chemicals, Panlite (registered trademark) TS-2080): 5 parts · Additive (manufactured by BASF Japan, Irganox1076): 1.5 parts · Alumina particles (AA03: manufactured by Sumitomo Chemical): 2 parts · Tetrahydrofuran: 500 parts

[0325] <Photoconductor 5> A photoconductor 5 was obtained in the same manner as the photoconductor 1, except that the following surface layer coating liquid 5 was used.

[0326] (Surface layer coating liquid 5) · Charge transport material of the above [Chemical Formula 3]: 7 parts · Binder resin of bisphenol Z type polycarbonate (manufactured by Teijin Chemicals, Panlite (registered trademark) TS-2050): 5 parts · Binder resin of bisphenol Z type polycarbonate (manufactured by Teijin Chemicals, Panlite (registered trademark) TS-2080): 5 parts · Additive (manufactured by BASF Japan, Irganox1076): 1.5 parts · Alumina particles (AA03: manufactured by Sumitomo Chemical): 2 parts · Silicon oil (manufactured by Shin-Etsu Chemical Co., Ltd., KF-50-100CS): 0.005 parts · Tetrahydrofuran: 500 parts

[0327] <Photoconductor 6> A photoconductor 6 was obtained in the same manner as the photoconductor 1 except that the following surface layer coating liquid 6 was used.

[0328] (Surface layer coating liquid 6) · Charge transport material of the above [Chemical Formula 3]: 6.5 parts · Binder resin of bisphenol Z type polycarbonate (manufactured by Teijin Chemicals, Panlite (registered trademark) TS-2040): 2 parts · Binder resin of bisphenol Z type polycarbonate (manufactured by Teijin Chemicals, Panlite (registered trademark) TS-2050): 8 parts · Additive (manufactured by BASF Japan, Irganox1076): 1.5 parts · Fluorine particles (manufactured by Mitsui DuPont Fluorochemicals, MPE-056): 2 parts · Silicon oil (manufactured by Shin-Etsu Chemical Co., Ltd., KF-50-100CS): 0.005 parts · Tetrahydrofuran: 400 parts

[0329] <Photoconductor 7> A photoconductor 7 was obtained in the same manner as the photoconductor 1 except that the following surface layer coating liquid 7 was used.

[0330] (Surface layer coating liquid 7) · Charge transport material of the above [Chemical Formula 3]: 7 parts · Binder resin of bisphenol Z type polycarbonate (manufactured by Teijin Chemicals Ltd., Panlite (registered trademark) TS-2040): 10 parts · Additive (manufactured by BASF Japan Ltd., Irganox1076): 1.5 parts · Alumina particles (AA03: manufactured by Sumitomo Chemical Co., Ltd.): 2 parts · Silicone oil (manufactured by Shin-Etsu Chemical Co., Ltd., KF-50-100CS): 0.005 parts · Tetrahydrofuran: 400 parts

[0331] <Photoconductor 8> A photoconductor 8 was obtained in the same manner as the photoconductor 1 except that the following surface layer coating liquid 8 was used.

[0332] (Surface layer coating liquid 8) · Charge transport material of the above [Chemical Formula 3]: 6 parts · Binder resin of bisphenol Z type polycarbonate (manufactured by Teijin Chemicals Ltd., Panlite (registered trademark) TS-2050): 2 parts · Binder resin of bisphenol Z type polycarbonate (manufactured by Teijin Chemicals Ltd., Panlite (registered trademark) TS-2080): 8 parts · Additive (manufactured by BASF Japan Ltd., Irganox1076): 1.5 parts · Alumina particles (AA03: manufactured by Sumitomo Chemical Co., Ltd.): 2 parts · Silicone oil (manufactured by Shin-Etsu Chemical Co., Ltd., KF-50-100CS): 0.005 parts · Tetrahydrofuran: 550 parts

[0333] <Friction coefficient of the photoconductor> The friction coefficient of the photoconductor surface was the friction coefficient of the photoconductor surface measured by the aforementioned Euler belt method.

[0334] Table 6 shows the results of measuring the surface hardness (Martens hardness), elastic work ratio (We / Wt value), and friction coefficient for the prepared photoconductors 1 to 8.

[0335]

Table 6

[0336] Next, the configuration of the image forming apparatus used in the verification experiment will be described.

[0337] The manufactured blades 1 to 9 and the manufactured photoreceptors 1 to 8 were mounted on a color printer (manufactured by Ricoh, RICOH PRO C9110) in the combinations shown in Table 7, and image forming apparatuses of Examples 1 to 9 and Comparative Examples 1 to 4 were manufactured. With this image forming apparatus, a 400,000-sheet actual paper feeding test was carried out under the following conditions.

[0338] · Paper for use: NBS Ricoh, My Paper A4 · Station used: Black · Output image: Image area ratios of 0%, 50%, and 100% (images with different image area ratios within the same chart are output). · Lubricant application means: Only in Example 7, the verification experiment was carried out after modifying the mechanism to not use the lubricant application means.

[0339]

Table 7

[0340] For Examples 1 to 9 and Comparative Examples 1 to 4 shown in Table 7, the following items were evaluated.

[0341] <Cleaning defect> Under the conditions of a vertical band pattern (in the paper feeding direction) with a width of 43 mm and three charts, the image after outputting 20 sheets (A4 landscape) was visually confirmed, and the cleaning defect was evaluated according to the following evaluation criteria. (Evaluation criteria) Good: Not occurred Fair: Occurred only at the ends Poor: Occurred over the entire surface

[0342] [[ID=^]] Using a microscope (manufactured by Keyence Corporation, digital microscope VHX-100), the blade edge was visually observed and evaluated according to the following evaluation criteria. (Evaluation criteria)​ Good: There are no chips or toner adhesion at the edge over the entire cleaning blade area. Acceptable: There are minute chips or toner adhesion at the edge. Unacceptable: There are obvious chips or toner adhesion at the edge.

[0343] <Wear width of blade edge> As shown in Fig. 15, the wear width as viewed from the blade tip surface side was measured by using a microscope (Keyence Corporation, Digital Microscope VHX-100) on the cross-section of an elastic blade coated in the same manner separately. The sample was cut into a cross-section using a trimming razor for SEM sample preparation made by Nitto EM. The wear width of the blade edge was evaluated according to the following evaluation criteria. (Evaluation criteria) Good: Wear width is less than 50 μm. Acceptable: Wear width is 50 μm or more and less than 100 μm. Unacceptable: Wear width is 100 μm or more.

[0344] <Observation of photoreceptor surface> Visual inspection and using a real color confocal microscope OPTELICS H1200 made by Lasertec Corporation, it was evaluated according to the following evaluation criteria. (Evaluation criteria) [[ID=^29]]Good: There are no scratches or toner adhesion over the entire photoreceptor surface. Acceptable: There are minute scratches or toner adhesion on a part of the photoreceptor surface. Unacceptable: There are obvious scratches or toner adhesion over the entire photoreceptor surface. ·Photoreceptor wear evaluation

[0345] <Reduction amount of photoreceptor film thickness> Among the parts with continuous output at image areas of 0%, 50%, and 100%, the film thickness at any 5 points was measured with an eddy current type film thickness gauge (Fisher Instruments Corporation, FISHERSCOPE (registered trademark) MMS), and the reduction amount of the film thickness from the initial stage was shown. Good: Reduction amount of film thickness is less than 1 μm. Acceptable: Reduction amount of film thickness is 1 μm or more and less than 3 μm. Unacceptable: Reduction amount of film thickness is 3 μm or more.

[0346] The results are shown in Table 8.

[0347] [Table 8]

[0348] From Table 8, in Examples 1 to 9, good cleaning performance was maintained over a long period, and the occurrence of abnormal wear of the photoreceptor and the cleaning blade, and the curling of the tip ridge portion of the cleaning blade were suppressed.

[0349] On the other hand, in Comparative Examples 1 to 4, good results were not obtained in the cleaning evaluation, and the occurrence of abnormal wear was observed.

[0350] As described above, the embodiments of the present invention have been described. However, the present invention is not limited to specific embodiments, and various modifications and changes are possible within the scope of the invention described in the claims. [Explanation of Reference Numerals]

[0351] 1 Image forming unit (process cartridge) 2 Frame 3 Photoreceptor 4 Charging roller 5 Developing device 6 Cleaning device 7 Primary transfer roller 8 Charging roller cleaner 10 Lubricant application device 14 Intermediate transfer belt 60 Transfer unit 62 Cleaning blade 62a Blade front surface 62b Blade lower surface 62c Tip ridge portion 621 Support member 622 Base material layer 623 Surface layer 624 Elastic member 80 Fixing unit 91 Conductive support 92 Photosensitive layer 921 Charge generation layer 922 Charge transport layer 93 Surface layer 94 Underlying layer 101 Fiber brush 103 Solid lubricant 140 Belt 140a, 140b Hook 141 Load 142 Digital force gauge 143 Photoconductor 144 Support base 162 Belt cleaning unit 162a Belt cleaning blade 500 Printer 621 Support member

Prior art documents

Patent documents

[0352]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Claims

1. A photoreceptor, A cleaning blade having an elastic member that contacts the surface of the photoreceptor and removes deposits adhering to the surface of the photoreceptor, and an image forming apparatus having the same, The photoreceptor, A conductive support, A photosensitive layer and a surface layer sequentially laminated on the conductive support, and having, The surface layer has a polycarbonate resin as a binder resin and any one of alumina particles, fluorine-containing resin particles, and silica particles as particles, and has a Martens hardness of 150 N / mm ２ or more and less than 180 N / mm ２ less than that, and an elastic work ratio of 35% or more and less than 45%, The cleaning blade, The elastic member has a base material layer and a surface layer, The surface layer has a tip ridge line portion, The surface layer has a domain having a polysiloxane structure with an average dispersion diameter of 0.1 μm or more and 5.0 μm or less in which dimethyl silicone oil is contained in a region from the surface including the tip ridge line portion of the elastic member to a depth of 100 μm. An image forming apparatus characterized by that.

2. The cleaning blade, The Martens hardness of the elastic member measured under the condition of a load of 1000 μN from the side of the surface layer at a position 20 μm away from the tip ridge line portion to the inside of the surface is 0.3 N / mm ２ or more and 8.0 N / mm ２ or less. The image forming apparatus according to claim 1.

3. The image forming apparatus according to claim 1 or 2, further comprising a lubricant application unit that applies a lubricant to the surface of the photoreceptor.

4. The image forming apparatus according to any one of claims 1 to 3, wherein the friction coefficient of the surface of the photoreceptor measured by the Euler belt method is 0.2 or more.

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