JP7714909B2 - Image forming device - Google Patents

Description

The present invention relates to an image forming apparatus .

In conventional electrophotographic image forming devices, after a toner image is transferred to transfer paper or an intermediate transfer body, a cleaning device is used to remove any unnecessary residual toner adhering to the surface of the photosensitive body. A known cleaning device uses a strip-shaped cleaning blade as a cleaning member, as it has a simple structure and excellent cleaning performance.

This cleaning blade is made of an elastic material such as polyurethane rubber. The base end of the cleaning blade is supported by a support member, and the ridged tip is pressed against the circumferential surface of the photosensitive drum, intercepting and scraping off any toner remaining on the photosensitive drum.

In response to recent demands for higher image quality, image forming devices are known that use small, nearly spherical toner particles formed by polymerization methods (hereafter referred to as polymerized toner). This polymerized toner has advantages such as higher transfer efficiency compared to conventional pulverized toner, making it possible to meet the above demands.

However, polymerized toner is difficult to remove sufficiently from the surface of the photoreceptor using a cleaning blade, resulting in poor cleaning. This is because polymerized toner, with its small particle size and excellent sphericity, slips through the small gap formed between the blade and the photoreceptor.

To prevent this type of polymerized toner from slipping through, it is necessary to increase the contact pressure between the photosensitive drum and cleaning blade to improve cleaning performance.

For example, Patent Document 1 describes a cleaning blade that is composed of an elastic blade (elastic blade) whose surface has been treated to reduce friction by impregnation with at least one compound selected from an isocyanate compound, a fluorine compound, and a silicone compound, and a surface layer made of an ultraviolet-curable resin that is harder than the elastic blade and covers the edge of the tip of the elastic blade.

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

Patent Document 3 describes a cleaning blade in which an elastic blade is impregnated with a silicone-containing UV-curable material, causing it to swell, and then irradiated with UV light to form a surface layer that is harder than the elastic blade at least on the contact portion of the cleaning blade that contacts the photosensitive drum.

Patent document 4 describes a cleaning blade in which an acrylate polymer is impregnated to a depth of 5 μm to 100 μm from the surface of the cleaning blade, the acrylate polymer is then laminated onto the surface of the cleaning blade, and the ultraviolet-curable material is cured by irradiating it with ultraviolet light.

However, increasing the contact pressure of the cleaning blade increases the friction between the photosensitive drum and the cleaning blade, causing the ridge at the tip of the cleaning blade to curl. Furthermore, this curling of the cleaning blade can lead to localized wear (abnormal wear) and chipping of the ridge at the tip, resulting in poor cleaning (a condition in which toner cannot be cleaned properly).

The objective of the present invention is to provide an image forming apparatus that suppresses abnormal wear and maintains good cleaning performance.

In order to solve the above-mentioned 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 to remove deposits adhered to the surface of the photoreceptor, wherein 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 having a polycarbonate resin as a binder resin and one of alumina particles, fluorine-containing resin particles, and silica particles as particles, and having a 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%, and the cleaning blade is characterized in that the elastic member has a base layer and a surface layer, the surface layer having a tip ridge portion, and the surface layer has a domain containing dimethylsilicone oil and 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 of the elastic member to a depth of 100 μm.

One aspect of the present invention provides an image forming apparatus that suppresses abnormal wear and maintains good cleaning performance.

FIG. 1 is a schematic diagram illustrating the configuration of a printer according to an embodiment of the present invention. FIG. 2 is a schematic configuration diagram of an imaging unit according to the present embodiment. 1 is a conceptual diagram illustrating a problem occurring in a conventional cleaning blade. FIG. 2 is an enlarged cross-sectional view showing an example of a state in which an example of a cleaning blade according to the present invention is in contact with the surface of an image bearing member. FIG. 2 is a perspective view showing an example of a cleaning blade according to the present embodiment. 1 is a schematic diagram of an example of a cleaning blade with high dimensional accuracy. 1 is a schematic diagram of an example of a cleaning blade with poor dimensional accuracy. FIG. 1 is a diagram for explaining a region from the surface including the tip ridge line to a depth of 100 μm (part 1). FIG. 2 is a diagram (part 2) for explaining the region from the surface including the tip ridge line to a depth of 100 μm. FIG. 2 is a conceptual diagram showing a layer structure of a photoreceptor in the present embodiment (an example in which a single-layer photosensitive layer and a surface layer are provided). FIG. 2 is a conceptual diagram showing a layer structure of a photoreceptor in the present embodiment (an example in which a laminated photosensitive layer and a surface layer are provided). 1 is a conceptual diagram showing a layer structure of a photoreceptor in the present embodiment (an example in which an undercoat layer, a laminated photosensitive layer, and a surface layer are provided). FIG. 2 is a schematic diagram illustrating the Euler belt method, which is a method for measuring the coefficient of friction of a photoreceptor surface. 1 shows an X-ray diffraction spectrum of titanyl phthalocyanine powder used as a charge generation material in this embodiment. FIG. 4 is a schematic diagram showing measurement points of the wear width of the elastic blade.

The following describes an embodiment of the present invention.

<Image forming apparatus>
The image forming apparatus according to this embodiment has a photoreceptor and a cleaning blade having an elastic member that comes into contact with the surface of the photoreceptor to remove any deposits adhering to the surface of the photoreceptor.

In the image forming apparatus of this embodiment, the photoreceptor has a conductive support, a photosensitive layer, and a surface layer laminated in this order on the conductive support. The surface layer of the photoreceptor contains a binder resin and particles. The surface layer of the photoreceptor has a 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 image forming apparatus of this embodiment, the cleaning blade has an elastic member having a base layer and a surface layer, and the surface layer has a tip ridge portion. The surface layer of the cleaning blade has domains having a polysiloxane structure with an average dispersed diameter of 0.1 μm or more and 5.0 μm or less in a region extending from the surface, including the tip ridge portion of the elastic member, to a depth of 100 μm.

Figure 1 is a schematic diagram of an electrophotographic printer, showing an example of an image forming apparatus according to this embodiment. Below, the image forming apparatus according to this embodiment will be described using the printer 500 shown in Figure 1.

Printer 500 has four imaging units 1Y, 1C, 1M, and 1K for yellow, magenta, cyan, and black (hereinafter referred to as Y, C, M, and K). These use different colors of Y, C, M, and K toner as the image-forming material to form images, but are otherwise similar in configuration.

Above the four imaging units 1, a transfer unit 60 is arranged, which includes an intermediate transfer belt 14 as an intermediate transfer body. The toner images of each color formed on the surfaces of the photosensitive members 3Y, 3C, 3M, and 3K of the imaging units 1Y, 1C, 1M, and 1K (details of which will be described later) are transferred onto the surface of the intermediate transfer belt 14 in a superimposed state.

In addition, an optical writing unit 40 serving as latent image forming means is disposed below the four imaging units 1. The optical writing unit 40 emits laser light L based on image information and irradiates the photosensitive elements 3Y, 3C, 3M, and 3K of each imaging unit 1Y, 1C, 1M, and 1K. This forms electrostatic latent images for Y, C, M, and K on the photosensitive elements 3Y, 3C, 3M, and 3K.

The optical writing unit 40 deflects laser light L emitted from a light source using a polygon mirror 41, which is rotated by a motor, and irradiates the light onto photosensitive elements 3Y, 3C, 3M, and 3K via multiple optical lenses and mirrors. Alternatively, an LDE array can be used for optical scanning.

Below the optical writing unit 40, a first paper feed cassette 151 and a second paper feed cassette 152 are arranged so as to be stacked vertically. Each of these paper feed cassettes contains a stack of transfer paper P, which serves as a recording medium, with the topmost transfer paper P being in contact with the first paper feed roller 151a and the second paper feed roller 152a, respectively.

When the first paper feed roller 151a is driven to rotate counterclockwise in FIG. 1 by a drive means (not shown), the top sheet of transfer paper P in the first paper feed cassette 151 is ejected toward the paper feed path 153, which is arranged to extend vertically. When the second paper feed roller 152a is driven to rotate counterclockwise in FIG. 1 by a drive means (not shown), the top sheet of transfer paper P in the second paper feed cassette 152 is ejected toward the paper feed path 153.

Multiple pairs of transport rollers 154 are arranged within the paper feed path 153. The transfer paper P fed into the paper feed path 153 is sandwiched between the rollers of these transport roller pairs 154 and transported within the paper feed path 153 from the bottom to the top in Figure 1.

A registration roller pair 55 is arranged upstream of the roller pair 154 in the transport direction of the paper feed path 153. As soon as the registration roller pair 55 sandwiches the transfer paper P fed from the transport roller pair 154 between its rollers, it temporarily stops the rotation of both rollers. The transfer paper P is then sent towards the secondary transfer nip (described below) at the appropriate time.

Figure 2 is a diagram showing the general configuration of one of the four imaging units 1. As shown in Figure 2, the imaging unit 1 is equipped with a drum-shaped photoreceptor 3 as a photosensitive member. Although the photoreceptor 3 is shown as being drum-shaped, it may also be sheet-shaped or endless belt-shaped.

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

The charging roller 4 is a charging member provided in the charging device as a charging means. The charging roller 4 is positioned at a predetermined distance from the photosensitive element 3 without contact, and charges the photosensitive element 3 to a predetermined polarity and a predetermined potential.

The surface of the photoreceptor 3, which has been uniformly charged by the charging roller 4, is irradiated with laser light L from the optical writing unit 40, which serves as a latent image forming means, based on image information, forming an electrostatic latent image. A charging roller cleaner 8 is provided in contact with the charging roller 6, and foreign matter adhering to the charging roller 6 is cleaned off.

The developing device 5 constitutes a developing means that converts the latent image formed on the surface of the photoreceptor 3 into a toner image. The developing device 5 has a developing roller 51 as a developer carrier. A developing bias is applied to this developing roller 51 from a power source (not shown). Inside the casing of the developing device 5, there are a supply screw 52 and an agitating screw 53 that transport and agitate the developer contained in the casing in opposite directions.

The developing device 5 is also provided with a doctor 54 for regulating the developer carried by the developing roller 51. The toner in the developer, which is stirred and transported by the twin screws of the supply screw 52 and the stirring screw 53, is charged to a predetermined polarity. The developer is then drawn up onto the surface of the developing roller 51, where it is regulated by the doctor 54, and the toner adheres to the latent image on the photoconductor 3 in the development area facing the photoconductor 3.

The cleaning device 6 is a cleaning means that cleans the toner remaining on the photoreceptor 3 after the toner image has been transferred to the intermediate transfer belt 14. The cleaning device 6 includes a fur brush 101 and a cleaning blade 62. The cleaning blade 62 abuts against the photoreceptor 3 in a counter direction to the direction of surface movement of the photoreceptor 3. Details of the cleaning blade 62 will be described later.

The primary transfer roller 7 is a primary transfer member provided in the primary transfer device as a primary transfer means that transfers the toner image on the surface of the photosensitive drum 3 to the intermediate transfer belt 14.

The lubricant applicator 10 is a lubricant applicator that applies lubricant to the surface of the photoreceptor 3 after cleaning by the cleaning device 6. The static elimination lamp (not shown) constitutes static elimination means that eliminates the surface potential of the photoreceptor 3 after cleaning. The lubricant applicator 10 is equipped with a solid lubricant 103, a lubricant pressure spring 103a, etc., and uses a fur brush 101 as an applicator brush that applies the solid lubricant 103 to the photoreceptor 3.

The lubricant application device 10 is an example of a lubricant application unit that constitutes part of the image forming apparatus according to this embodiment.

The solid lubricant 103 is held by bracket 103b and is pressed toward the fur brush 101 by lubricant pressure spring 103a. The fur brush 101, which rotates in the same direction as the photoreceptor 3, scrapes off the solid lubricant 103, applying the lubricant to 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 when no image is being formed.

In this embodiment, a non-contact proximity charging system is used, in which the charging roller 4 is placed close to the photosensitive element 3. However, known charging devices such as corotrons, scorotrons, and solid-state chargers can also be used. Of these charging systems, the contact charging system or the non-contact proximity charging system is preferred, as it offers advantages such as high charging efficiency, low ozone generation, and the ability to miniaturize the device.

Light sources for the laser light L of the optical writing unit 40 and the static elimination lamp can include various light-emitting devices such as fluorescent lamps, tungsten lamps, halogen lamps, mercury lamps, sodium lamps, light-emitting diodes (LEDs), semiconductor lasers (LDs), and electroluminescent devices (ELs).

In addition, various filters such as sharp-cut filters, band-pass filters, near-infrared cut filters, dichroic filters, interference filters, and color temperature conversion filters can be used to irradiate only light in the desired wavelength range.

Of these light sources, light-emitting diodes and semiconductor lasers are preferred because they have high irradiation energy and emit long-wavelength light of 600 to 800 nm.

In addition to the intermediate transfer belt 14, the transfer unit 60 also includes a belt cleaning unit 162, a first bracket 63, a second bracket 64, and other components. It also includes four primary transfer rollers 7Y, 7C, 7M, and 7K, a secondary transfer backup roller 66, a drive roller 67, an auxiliary roller 68, and a tension roller 69.

The intermediate transfer belt 14 is stretched across these eight roller members and moves endlessly counterclockwise in FIG. 1 as driven by the rotation of the drive roller 67. The four primary transfer rollers 7Y, 7C, 7M, and 7K sandwich the endlessly moving intermediate transfer belt 14 between themselves and the photosensitive elements 3Y, 3C, 3M, and 3K, forming primary transfer nips.

A transfer bias of the opposite polarity (e.g., positive) to the toner is then applied to the back surface (inner surface of the loop) of the intermediate transfer belt 14. As the intermediate transfer belt 14 passes through the primary transfer nips for Y, C, M, and K in sequence as it moves endlessly, the Y, C, M, and K toner images on the photoreceptors 3Y, 3C, 3M, and 3K are superimposed and primarily transferred onto its surface. This forms a four-color superimposed toner image (hereinafter referred to as a four-color toner image) on the intermediate transfer belt 14.

The secondary transfer backup roller 66 sandwiches the intermediate transfer belt 14 between itself and a secondary transfer roller 70 disposed outside the loop of the intermediate transfer belt 14, forming a secondary transfer nip. The previously described registration roller pair 55 sends the transfer paper P sandwiched between the rollers toward the secondary transfer nip at a timing that synchronizes it with the four-color toner image on the intermediate transfer belt 14.

The four-color toner image on the intermediate transfer belt 14 is transferred in bulk to the transfer paper P in the secondary transfer nip due to the effects of the 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. This, combined with the white color of the transfer paper P, forms a full-color toner image.

After passing through the secondary transfer nip, residual toner that was not transferred to the transfer paper P remains on the intermediate transfer belt 14. This is cleaned by the belt cleaning unit 162. The belt cleaning unit 162 abuts the surface of the intermediate transfer belt 14 with a belt cleaning blade 162a, which scrapes off and removes residual toner from the intermediate transfer belt 14.

The first bracket 63 of the transfer unit 60 swings at a predetermined rotation angle around the rotation axis of the auxiliary roller 68 as the solenoid (not shown) is turned on and off.

When forming a monochrome image, the printer 500 drives the aforementioned solenoid to slightly rotate the first bracket 63 counterclockwise in FIG. 1. This rotation causes the primary transfer rollers 7Y, 7C, and 7M for Y, C, and M to revolve counterclockwise in FIG. 1 around the rotation axis of the auxiliary roller 68, thereby separating the intermediate transfer belt 14 from the photosensitive elements 3Y, 3C, and 3M for Y, C, and M.

Of the four imaging units 1Y, 1C, 1M, and 1K, only the imaging unit 1K for K is driven to form a monochrome image. This avoids wear and tear on the components that make up the imaging unit 1 due to unnecessary driving of the imaging units 1 for Y, C, and M when forming a monochrome image.

A fixing unit 80 is disposed above the secondary transfer nip in Figure 1. This fixing unit 80 includes a pressure/heat roller 81 containing a heat source such as a halogen lamp, and a fixing belt unit 82.

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 drive roller 86, a temperature sensor (not shown), and other components. The endless fixing belt 84 moves endlessly in the counterclockwise direction in FIG. 1 while being tensioned by the heating roller 83, tension roller 85, and drive roller 86.

During this endless movement, the fixing belt 84 is heated from the back side by the heating roller 83. The pressure and heat roller 81, which is driven to rotate clockwise in Figure 1, contacts the heated fixing belt 84 from the front side at the point where it is wrapped around the heating roller 83. This forms a fixing nip where the pressure and heat roller 81 and fixing belt 84 come into contact.

A temperature sensor (not shown) is arranged on the outside of the loop of the fixing belt 84, facing the surface of the fixing belt 84 with a specified gap between them, and detects the surface temperature of the fixing belt 84 immediately before it enters the fixing nip. The detection results are sent to a fixing power supply circuit (not shown). Based on the detection results from the temperature sensor, the fixing power supply circuit turns on and off the power supply to the heat sources contained within the heating roller 83 and pressure heating roller 81.

After passing through the secondary transfer nip described above, the transfer paper P is separated from the intermediate transfer belt 14 and sent into the fixing unit 80. As the transfer paper P is conveyed from the bottom to the top in FIG. 1 while being sandwiched in the fixing nip within the fixing unit 80, it is heated and pressed by the fixing belt 84, thereby fixing the full-color toner image to the transfer paper P.

After the transfer paper P has been fixed in this way, it passes between the rollers of the discharge roller pair 87 and is then discharged outside the machine. A stack section 88 is formed on the top surface of the casing of the printer 500 main body, and the transfer paper P discharged outside the machine by the discharge roller pair 87 is stacked in this stack section 88 one by one.

Four toner cartridges 100Y, 100C, 100M, and 100K containing Y, C, M, and K toner are arranged above the transfer unit 60. The Y, C, M, and K toner in the toner cartridges 100Y, 100C, 100M, and 100K are supplied as appropriate to the developing devices 5Y, 5C, 5M, and 5K of the imaging units 1Y, 1C, 1M, and 1K.

These toner cartridges 100Y, 100C, 100M, and 100K can be attached to and detached from the printer body independently of the imaging units 1Y, 1C, 1M, and 1K.

Next, we will explain the image formation operation of the printer 500.

When a print execution signal is received from an operation unit (not shown) or the like, a predetermined voltage or current is applied sequentially and at a predetermined timing to the charging roller 4 and the developing roller 51. Similarly, a predetermined voltage or current is applied sequentially and at a predetermined timing to the optical writing unit 40 and light sources such as the static elimination lamp. Synchronously with this, the photosensitive drum 3 is rotated in the direction of the arrow in Figure 1 by a photosensitive drum drive motor (not shown) serving as a driving means.

When the photoreceptor 3 rotates in the direction of the arrow in Figure 1, the surface of the photoreceptor 3 is first uniformly charged to a predetermined potential by the charging roller 4. Then, a laser beam L corresponding to the image information is irradiated onto the photoreceptor 3 from the optical writing unit 40, and the portions of the photoreceptor 3 surface irradiated by the laser beam L are discharged, forming an electrostatic latent image.

The surface of the photoreceptor 3, on which the electrostatic latent image is formed, is rubbed by a magnetic brush of 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 is moved toward the electrostatic latent image by a predetermined developing bias applied to the developing roller 51, and is turned into a toner image (developed).

A similar image creation process is performed in each imaging unit 1, and toner images of each color are formed on the surface of each photoconductor 3Y, C, M, K of each imaging unit 1Y, C, M, K.

In this way, in the printer 500, the electrostatic latent image formed on the photosensitive element 3 is reverse-developed by the developing device 5 using negatively charged toner. In this embodiment, an example using an N/P (negative/positive: toner adheres to areas with a low potential) non-contact charging roller system has been described, but the present invention is not limited to this.

The toner images of each color formed on the surface of each photoreceptor 3Y, 3C, 3M, and 3K are sequentially transferred (primary transfer) onto the surface of the intermediate transfer belt 14 so that they overlap. This forms a four-color toner image on the intermediate transfer belt 14.

The four-color toner image formed on the intermediate transfer belt 14 is transferred onto transfer paper P, which 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 fed to the secondary transfer nip. At this time, the transfer paper P stops briefly while sandwiched between the registration roller pair 55, and is then fed to the secondary transfer nip in synchronization with the leading edge of the image on the intermediate transfer belt 14.

The transfer paper P with the toner image transferred is separated from the intermediate transfer belt 14 and transported to the fixing unit 80. As the transfer paper P with the toner image transferred passes through the fixing unit 80, the toner image is fixed onto the transfer paper P by the action of heat and pressure, and the transfer paper P with the fixed toner image is ejected outside the printer 500 and stacked in the stack section 88.

Meanwhile, the surface of the intermediate transfer belt 14, from which the toner image has been transferred to the transfer paper P at the secondary transfer nip, has residual toner removed by the belt cleaning unit 162. Furthermore, the surface of the photoconductor 3, from which the toner images of each color have been transferred to the intermediate transfer belt 14 at the primary transfer nip, has residual toner removed by the cleaning device 6, and after lubricant is applied by the lubricant application device 10, the surface is neutralized by the neutralization lamp.

As shown in Figure 1, the imaging unit 1 of the printer 500 is provided (housed) in a frame 2 with a photosensitive member 3 and process means such as a charging roller 4, a developing device 5, a cleaning device 6, and a lubricant application device 10. The imaging unit 1 is detachable from the printer 500 body as a process cartridge.

In the printer 500, the image-forming unit 1 is designed so that the photosensitive element 3 and each process means serving as a process cartridge are replaced as a whole, but this configuration is not limited to this. For example, the printer 500 may be designed so that the photosensitive element 3, charging roller 4, developing device 5, cleaning device 6, and lubricant application device 10 can be replaced individually with new ones.

Next, we will explain the toner suitable for the printer 500 of this embodiment.

To improve image quality, it is preferable to use polymerized toner manufactured by suspension polymerization, emulsion polymerization, or dispersion polymerization, which facilitates high circularity and small particle size. For example, it is preferable to use polymerized toner with a circularity of 0.97 or more and a volume average particle size of 5.5 μm or less. Using a polymerized toner with an average circularity of 0.97 or more and a volume average particle size of 5.5 μm or less allows for the production of images with higher resolution.

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

Specifically, 0.1 to 0.5 ml of a surfactant, preferably alkylbenzene sulfonate, is added as a dispersant to 100 to 150 ml of water in a container from which impurities have been removed, and approximately 0.1 to 0.5 g of the measurement sample (toner) is then added. The suspension with the dispersed toner is then dispersed in an ultrasonic disperser for approximately 1 to 3 minutes, until the dispersion concentration reaches 3,000 to 10,000 particles/μl. This suspension is then placed in the above-mentioned analyzer and the shape and distribution of the toner are measured.

The volume average particle size can be determined using the Coulter Counter method. Specifically, data on the number distribution and volume distribution of toner measured using a Coulter Multisizer 2e (manufactured by Coulter) is sent to a personal computer via an interface (manufactured by Nikkaki Co., Ltd.) and analyzed.

More specifically, a 1% NaCl aqueous solution using primary sodium chloride is prepared as the electrolyte. Then, 0.1 to 5 ml of a surfactant, preferably alkylbenzene sulfonate, is added as a dispersant to 100 to 150 ml of this electrolyte solution. 2 to 20 mg of toner as the test sample is then added, and the mixture is dispersed in an ultrasonic disperser for approximately 1 to 3 minutes.

Then, place 100-200 ml of aqueous electrolyte solution in a separate beaker, add the post-dispersion solution to a specified concentration, and run it through the Coulter Multisizer Model 2e. Use a 100 μm aperture and measure the particle sizes of 50,000 toner particles.

Thirteen channels are used, with diameters ranging from 2.00 μm to less than 2.52 μm; from 2.52 μm to less than 3.17 μm; from 3.17 μm to less than 4.00 μm; from 4.00 μm to less than 5.04 μm; from 5.04 μm to less than 6.35 μm; from 6.35 μm to less than 8.00 μm; from 8.00 μm to less than 10.08 μm; from 10.08 μm to less than 12.70 μm; from 12.70 μm to less than 16.00 μm; from 16.00 μm to less than 20.20 μm; from 20.20 μm to less than 25.40 μm; from 25.40 μm to less than 32.00 μm; and from 32.00 μm to less than 40.30 μm, and are intended for toner particles with particle diameters of 2.00 μm to 32.0 μm.

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

When attempting to remove such polymerized toner with a conventional cleaning blade in the same way as conventional pulverized toner is removed from the surface of the photoreceptor, the polymerized toner cannot be sufficiently removed from the surface of the photoreceptor, resulting in poor cleaning. Therefore, when an attempt is made to improve cleaning performance by increasing the contact pressure of the cleaning blade against the photoreceptor, the cleaning blade wears out prematurely, which is a problem.

Figure 3 is a conceptual diagram of the problems that occur with conventional cleaning blades. Furthermore, as the friction between the cleaning blade and the photosensitive drum increases, the portion of the cleaning blade that contacts the surface of the photosensitive drum (the blade's leading edge) is pulled in the direction of movement of the photosensitive drum and becomes curled up. When the portion of the cleaning blade that contacts the photosensitive drum becomes curled up, various problems occur, including abnormal noise and vibration, and wear (grooving) and chipping of the blade's leading edge.

After extensive research, the inventors discovered an image forming device in which the surface layer of a cleaning blade has domains (regions) with a polysiloxane structure having an average dispersion diameter of 0.1 μm or more and 5.0 μm or less in a region extending to a depth of 100 μm from the surface, including the tip ridge.

It was found that an image forming device with this configuration suppresses abnormal wear of the photosensitive element and cleaning blade, and curling of the cleaning blade's leading edge. Furthermore, it was found that this image forming device can maintain good cleaning performance over the long term by improving the ability of the cleaning blade's leading edge to follow the photosensitive element.

<Cleaning blade>
An example of the cleaning blade in this embodiment will now be described with reference to Figures 4 and 5. Figure 4 is an explanatory diagram showing a state in which the cleaning blade 62 is in contact with the surface of the photoreceptor 3, and Figure 5 is a perspective view of the cleaning blade 62.

In Figures 4 and 5, the cleaning blade 62 has a support member 621 and an elastic member 624. The elastic member 624 also has a base layer (substrate) 622 and a surface layer 623. In this embodiment, the base layer 622 is strip-shaped. The cleaning blade 62 also has a blade tip surface 62a, a blade undersurface 62b, and a tip ridge portion 62c (hereinafter sometimes referred to as the abutment portion or edge portion).

In this embodiment, the longitudinal surface of the base layer 622 constituting the elastic member 624, which faces the downstream side B in the direction of travel of the photosensitive element 3 (the member to be cleaned) (the rotation direction indicated by A and B in Figure 4), is referred to as the bottom surface of the base layer 622. Furthermore, the leading edge surface of the base layer 622, which faces the upstream side A in the rotation direction of the member to be cleaned and includes the leading edge portion 62c, is referred to as the leading edge surface of the base layer 622.

In Figure 4, the longitudinal surface of the elastic member 624 that faces the downstream side B in the rotational direction of the member to be cleaned corresponds to the blade lower surface 62b. Furthermore, the tip surface of the elastic member 624, including the tip ridge portion 62c, that faces the upstream side A in the rotational direction of the member to be cleaned corresponds to the blade tip surface 62a.

The contact portion of the elastic member 624 that contacts the surface of the member to be cleaned includes the leading edge portion 62c of the elastic member 624. Furthermore, if the leading edge portion 62c is turned up or if the linear pressure is high, part of the blade leading surface 62a may also become the contact portion.

The cleaning blade 62 is an example of a cleaning blade that constitutes part of the image forming apparatus according to this embodiment. The cleaning blade 62 is also an example of a cleaning blade according to this embodiment.

<Elastic member>
The elastic member 624 comes into contact with the surface of the photoreceptor 3 (the member to be cleaned) to remove any deposits adhering to the surface of the member to be cleaned. The elastic member 624 has at least a base layer 622 and a surface layer 623, and may further have other parts as necessary.

By having the base material layer 622 and the surface layer 623, the elastic member 624 has good dimensional accuracy in the longitudinal direction, even when the elastic member 624 has domains with a siloxane compound or polysiloxane structure. The reasons for this are thought to be as follows.

If an elastic member is made from only a single layer of urethane rubber containing a siloxane compound, the cutting blade will slip when cutting the elastic member to the size required for use due to the low coefficient of friction derived from the domains on the surface that have a siloxane compound or polysiloxane structure. As a result, it is difficult to achieve dimensional precision with elastic members made from only a single layer of urethane rubber containing a siloxane compound.

In contrast, in this embodiment, when the elastic member 624 has a base layer 622 and a surface layer 623 having domains with a siloxane compound or polysiloxane structure, the cutting blade can be inserted from the base layer 622 side, enabling cutting with good dimensional accuracy.

If the longitudinal dimensional accuracy is poor, the deviation in the longitudinal pressure when the blade is pressed against the photosensitive member will be large (high pressure in long dimensions and low pressure in short dimensions). If the deviation in the pressing pressure is large, toner will slip through where the pressure is weak, resulting in poor image quality. It is preferable that the longitudinal deviation be, for example, 100 μm or less.

Figure 6 shows an example of a cleaning blade with good dimensional accuracy. In the cleaning blade 62 shown in Figure 6, the length X from the end of the support member 621 opposite the elastic member 624 side to the tip ridge 62c of the elastic member 624 is uniform in the longitudinal direction. In this case, there is little deviation in pressure in the longitudinal direction when the blade is pressed against the photosensitive element 3.

Figure 7 shows an example of a cleaning blade with poor dimensional accuracy. In the cleaning blade 62 shown in Figure 7, the length X from the end of the support member 621 opposite the elastic member 624 side to the leading edge portion 62c of the elastic member 624 is uneven in the longitudinal direction. In this case, there is a large deviation in pressure in the longitudinal direction when the cleaning blade 62 is pressed against the photosensitive element 3.

<<Surface layer>>
The surface layer 623 has a leading edge portion 62c. The surface layer 623 has domains 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 leading edge portion 62c to a depth of 100 μm. In the surface layer 623, the domains may be contained in locations other than the leading edge portion 62c. The surface including the leading edge portion 62c corresponds to the above-mentioned blade undersurface 62b (the surface facing the downstream side B in the rotation direction of the member to be cleaned).

A domain is a region having a polysiloxane structure. The polysiloxane structure is derived from, for example, a siloxane-based compound. A domain is formed, for example, by aggregation of siloxane-based compounds. In this case, the siloxane-based compounds that form the domain may or may not be bonded to a matrix component.

A siloxane compound is a compound that contains a siloxane bond, such as silicone. Silicones exist in the form of silicone oil, silicone resin, and silicone grease. Siloxane bonds have greater bond energy than carbon bonds and can exist more stably. Siloxane compounds have low surface free energy and excellent release and lubricity.

As a siloxane-based compound, a compound made of silicone is preferred, and the silicone described below can be used.

In this embodiment, the average dispersion diameter of the domains is 0.1 μm or more and 5.0 μm or less, and preferably 0.5 μm or more and 3.0 μm or less.

When the average dispersion diameter of the domains is 0.1 μm or greater, the dispersion diameter is large or the compatibility is poor, making it easier to reduce the frictional force with the member being cleaned (e.g., photoreceptor 3) and preventing curling of the blade tip. Furthermore, when the average dispersion diameter of the domains is 5.0 μm or less, contamination caused by the domains, which are aggregates of siloxane-based compounds, adhering to the photoreceptor surface is suppressed, preventing deterioration of image quality.

Furthermore, if the average dispersion diameter of the domains is 0.5 μm or more, curling at the tip of the blade can be further suppressed, even when images are continuously output that result in less toner being input to the blade. Furthermore, if the average dispersion diameter of the domains is 3.0 μm or less, the dispersion diameter is smaller than the particle size of ordinary toner, making it more unlikely that toner will adhere to the tip of the blade.

The average dispersion diameter can be calculated by measuring the dispersion diameter of 100 or more domains in a 100 μm area including any one of the tip ridges 62c, and calculating the average value by number. For example, the blade can be cut at any location to expose the cross section, and the 100 μm area including the tip ridge 62c can be photographed using a laser microscope or SEM, and the dispersion diameter can be measured from the image.

The dispersion diameter can also be measured by calculating it from a binarized image using image analysis software such as ImagePro. Whether the domains in the observed image have a polysiloxane structure can be confirmed using EDS (energy dispersive X-ray spectrometry) or similar.

The region from the surface including the tip ridge 62c to a depth of 100 μm is region Y as shown in Figures 8 and 9. Figure 8 is a diagram showing the position of region Y, and Figure 9 is an enlarged view of region Y. In Figure 9, the symbol S indicates a domain having a polysiloxane structure.

The average thickness of the surface layer 623 is not particularly limited and can be selected appropriately depending on 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.

When the average thickness is 50 μm or more, even if the surface becomes worn during long-term use, the surface exposed after wear also has domains with a polysiloxane structure, and even when worn, the part in contact with the photosensitive element always has domains with a polysiloxane structure, allowing a low coefficient of friction to be maintained. Furthermore, when the average thickness is 500 μm or less, deterioration in dimensional accuracy during processing due to the influence of the surface layer 623 having domains with a polysiloxane structure can be further suppressed.

Here, the average film thickness of the surface layer 623 at the contact portion can be determined by taking the arithmetic mean value of measurements taken at 10 arbitrary locations on the surface layer 623 at the contact portion.

The method for measuring the thickness of the surface layer 623 at the contact portion is not particularly limited and can be selected appropriately depending on the purpose. For example, a method can be used to measure the cut surface including the surface layer 623 at the contact portion using a microscope. Specifically, for example, the blade tip surface 62a is held facing upward and observed under a microscope to measure the thickness of the surface layer 623.

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

When the Martens hardness is 0.3 N/ ^mm2 or more, the tip ridge portion 62c of the cleaning blade 62 is less likely to deform, and curling of the tip ridge portion 62c can be more effectively prevented, and when the Martens hardness is 8.0 N/ ^mm2 or less, chipping of the blade tip can be more effectively prevented.

The method for measuring Martens hardness (HM) is as follows. To measure Martens hardness (HM), for example, a hardness tester (Fisher Instruments, Microhardness Tester HM-2000) is used.

The Martens hardness is measured by pressing a Vickers indenter into the tip surface of the base layer 622 with a force of 1.0 mN for 10 seconds, holding it in place for 5 seconds, and then removing it with a force of 1.0 mN for 10 seconds. The measurement position is a position 20 μm inward from the tip ridge 62c of the lower surface S of the elastic member 624. The measurement method is to cut the tip of the elastic member 624 to a width of approximately 1 cm, fix it to a slide glass or the like with adhesive or double-sided tape so that the lower surface S faces upward, and measure the measurement position described above.

The surface layer 623 of the elastic member 624 contains, for example, a layer-constituting resin component and a polysiloxane component that forms a domain. Specifically, in the surface layer 623, the polysiloxane component is dispersed in the layer-constituting resin component.

In other words, the surface layer 623 has a sea-island structure in which the layer-forming resin component forms the sea and the islands are domains formed by aggregation of the polysiloxane structure. The sea-island structure exists, for example, at least in a region extending to a depth of 100 μm from the surface, including the tip ridge portion 62c. The layer-forming resin component and the polysiloxane component may or may not be chemically bonded.

In the surface layer 623, the area ratio of the domains in the cross section of region Y is not particularly limited and can be selected appropriately depending on the purpose. In order to maximize the effects of the present invention, the area ratio of the domains is preferably 0.1% to 40%, more preferably 0.5% to 30%, and even more preferably 1.0% to 20%.

The area ratio of the domain in the cross section of the region can be determined, for example, by the following method. The blade is cut at any location to expose the cross section, and a 100 μm area including the tip ridge 62c is photographed using a laser microscope or SEM. The area ratio occupied by the siloxane-based compound is calculated from the image. The area ratio can be determined by calculating the area ratio from a binarized image using image analysis software such as ImagePro.

The surface layer 623 can be obtained, for example, by curing the following second composition. The second composition is, for example, the following first composition in an emulsified state, which contains a curing agent made of an active hydrogen compound.

<<First composition>>
The first composition contains at least one of the following components A and B, and component C.
A: NCO-terminated modified silicone prepolymer B: Silicone oil C: NCO-terminated urethane prepolymer

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

The modified silicone is a silicone having at least one hydroxyl group at the end, and commercially available products can be used. The modified silicone is selected from those that can react with the first polyisocyanate to form a prepolymer having an NCO group at the end. Specifically, the modified silicone has a hydroxyl group and an amino group at the end, and from the standpoint of stability, hydroxyl-modified silicone is preferred.

Examples of modified silicones include KF-6000, KF-6001, KF-6002, KF-6003, X-22-176F, X-22-176DX, and X-22-176GX-A (all commercially available products from Shin-Etsu Silicones Co., Ltd.). Modifications at the terminals include one terminal, both terminals, and side chains, but as described below, one terminal modification is more preferred in terms of the efficiency with which the silicone functions as a surfactant.

The first polyisocyanate is a compound that bonds to the end of the modified silicone via a urethane bond, resulting in an isocyanate group (NCO) at the end. Details of the first polyisocyanate will be described later.

NCO-terminated modified silicone prepolymer is a silicone prepolymer with NCO groups at the terminals, obtained by reacting a modified silicone with a first polyisocyanate. NCO-terminated modified silicone prepolymer can be obtained by mixing approximately twice the equivalent amount of first polyisocyanate relative to the functional groups on the modified silicone, heating and stirring the mixture.

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

General polyorganosiloxanes can be used as silicone oils. To ensure stable dispersion in the polyurethane/urea matrix, silicone oils with poor compatibility with the matrix are preferred. Such silicone oils are dispersed in an emulsified state in NCO-terminated urethane prepolymer, for example, using an NCO-terminated modified silicone prepolymer as a surfactant.

Among silicone oils, dimethyl silicone is more preferred. Dimethyl silicone oil is the most commonly used silicone oil, and commercially available products from various companies can be used. Note that, since higher viscosity requires more energy during the emulsification process, silicones with a viscosity of approximately 1 to 10,000 mPa·s/25°C are preferably used.

[C: NCO-terminated urethane prepolymer]
The NCO-terminated urethane prepolymer is a prepolymer having an isocyanate group at the end, which is obtained by reacting a polyol with a second polyisocyanate.

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

The second polyisocyanate is a compound that reacts with the terminal hydroxyl groups of the polyol to bond via a urethane bond, resulting in an isocyanate group (NCO) at the end.

Polyisocyanate compounds used as the first polyisocyanate and the second polyisocyanate include, for example, 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'-dimethyldiphenyl diisocyanate, Examples include diisocyanate-4,4'-dicyclohexylmethane, 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, and cyclohexylene-1,4-diisocyanate.

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

Specifically, the reactivity of aromatic polyisocyanates is greater than that of aliphatic polyisocyanates, and the reactivity is reduced by steric hindrance such as methyl groups in the side chains. This can be inferred from the following literature on urethanes:

・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)
・Polyurethane Resin Handbook, edited by Keiji Iwata, Nikkan Kogyo Shimbun (1987)
- Curing Agents for Polyurethane Resin Paints, Yoshiaki Takanaka, Journal of the Japan Color Materials Association, 49 (1976)

As such, aromatic polyisocyanates generally have higher reactivity with curing agents than aliphatic or alicyclic polyisocyanates, so, for example, the first polyisocyanate may be an aromatic polyisocyanate and the second polyisocyanate may be an aliphatic or alicyclic polyisocyanate. Furthermore, both the first and second polyisocyanates may be aromatic polyisocyanates or aliphatic or alicyclic polyisocyanates.

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

Specific examples include a combination of xylylene diisocyanate (high aliphatic reactivity) as the first polyisocyanate and dicyclohexylmethane 4,4'-diisocyanate (low aliphatic reactivity) as the second polyisocyanate.

NCO-terminated urethane prepolymers are the main component that forms the matrix of cured urethane resins, and can be synthesized or selected from commercially available products depending on the desired physical properties. For example, they can be obtained by mixing a long-chain polyol, such as polyester polyol, polyether polyol, or polycarbonate polyol, with a molecular weight of 500 to 4000, with a second polyisocyanate in an amount approximately twice the equivalent of the hydroxyl groups on the polyol, and then heating and stirring.

The NCO-terminated urethane prepolymer can be selected from commercially available products as long as it satisfies the requirements for the relative reactivity of the NCO-terminated modified silicone prepolymer with the first polyisocyanate.

The first composition contains at least one of component A and component B, and component C, and, for example, becomes emulsified when mixed.

In other words, the NCO-terminated silicone prepolymer of component A acts as a surfactant, keeping the silicone oil of component B in an emulsified state in the NCO-terminated urethane prepolymer of component C. In other words, the NCO-terminated silicone prepolymer coordinates around the silicone oil particles to form micelles, which then become an emulsion dispersed in the NCO-terminated urethane prepolymer.

As described above, the first composition can be, for example, an emulsion in which an NCO-terminated urethane prepolymer is dispersed with an NCO-terminated modified silicone prepolymer and silicone oil. A typical emulsifying device such as a high-speed mixer or homogenizer can be used as the dispersing device.

The first composition can be quickly produced as a uniform, milky-white dispersion by dispersing an NCO-terminated modified silicone prepolymer in an NCO-terminated urethane prepolymer and then dispersing silicone oil.

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

The curing agent is an active hydrogen-containing compound that is reactive with NCO groups, specifically a polyhydroxy compound or a polyamine compound. When a polyhydroxy compound is used as the curing agent, the matrix resin (layer-constituting resin) becomes a polyurethane resin. When a polyamine is used as the curing agent, the matrix resin becomes a polyurethane-urea resin.

Since it is effective to rapidly promote the reaction between the NCO-terminated silicone prepolymer that forms the shell and the curing agent, it is preferable to use a curing agent that contains a polyamine with an NCO equivalent equal to or greater than the silicone prepolymer.

The polyhydric hydroxy compound may be used together with a polyamine as a chain extender. Furthermore, known urethane curing catalysts (amines, organometallics) can also be used in combination to properly promote the curing reaction.

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

Examples of aliphatic polyhydric alcohols 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, and 1,3-bis(hydroxyethoxy)benzene.

Examples of polyamine compounds include 4,4'-methylenebis(2-chloroaniline), diethyltoluenediamine, and dimethylthiotoluenediamine.

The second composition is thermally cured in a specified mold or the like to become a cured polyurethane/urea resin.

The second composition contains an NCO-terminated silicone prepolymer, an NCO-terminated urethane prepolymer, and a curing agent that is an active hydrogen-containing compound reactive with NCO groups. By reacting the NCO groups with the curing agent, a cured polyurethane resin is formed.

Furthermore, it is preferable that the first polyisocyanate added to the end of the NCO-terminated silicone prepolymer and the second polyisocyanate added to the end of the NCO-terminated urethane prepolymer have a higher reactivity with the curing agent than the second polyisocyanate.

In this case, the NCO-terminated modified silicone prepolymer that forms the micelles reacts with the curing agent first, forming a core-shell structure in which the silicone oil forms the core and the cured NCO-terminated modified silicone prepolymer forms the shell.

In other words, when the NCO-terminated silicone prepolymer that forms the micelles reacts with the curing agent first, pseudo-capsules are formed in which the silicone oil is immobilized within the micelles. The NCO-terminated urethane prepolymer that forms the matrix then reacts with the curing agent and hardens, resulting in a cured urethane resin in which the core-shell structure is stably dispersed within the urethane/urea matrix.

The content of the siloxane compound in the cured urethane resin (surface layer 623) can be selected as appropriate, but is preferably 0.1% by mass or more and 20% by mass or less, and more preferably 1% by mass or more and 10% by mass or less, relative to the cured product (surface layer 623).

When the content of siloxane-based compounds in the cured urethane resin is 0.1% by mass or more, the coefficient of friction is reduced, and curling of the tip ridge portion 62c can be suppressed. When the content of siloxane-based compounds in the cured urethane resin is 20% by mass or less, migration of the siloxane-based compound components to the member being cleaned (e.g., photoreceptor 3) and contamination of the member being cleaned can be suppressed.

When the siloxane-based compound is present uniformly throughout the surface layer 623, the content of the siloxane-based compound in the cured urethane resin product can be determined by measuring at any position on the surface layer 623. When the siloxane-based compound is unevenly distributed in or near a region extending from the surface, including the tip ridge portion 62c, to a depth of 100 μm, the content of the siloxane-based compound in the cured urethane resin product is the content in that region.

<<Base material layer>>
The shape, size, material, structure, etc. of the base material layer 622 of the elastic member 624 are not particularly limited, and can be appropriately selected depending on the purpose.

The shape of the base material layer 622 in the elastic member 624 can be, for example, a flat plate, a strip, or a sheet. The shape of the base material layer 622 can also be, for example, a shape having a pair of plate surfaces that face each other in the thickness direction of the base material layer 622, and two pairs of end surfaces that are perpendicular to the plate surfaces and face each other in the in-plane direction of the plate surfaces.

The size of the base material layer 622 in the elastic member 624 can be selected appropriately, for example, depending on the size of the member to be cleaned. As a material for the base material layer 622 in the elastic member 624, polyurethane rubber, polyurethane elastomer, etc., are preferably used, as these materials tend to provide high elasticity.

The structure of the base material layer 622 in the elastic member 624 is not particularly limited and can be selected appropriately depending on the purpose. Examples include a single-layer structure made of one material, a two-layer structure made of two different materials molded together, and a multi-layer structure made of several different materials molded together.

When manufacturing the base layer 622 of the elastic member 624, which is made up of two or more laminated layers, raw materials with different mixture ratios can be continuously injected into a centrifugal molding die before each layer is completely hardened, allowing the layers to be molded together in an integrated manner without delamination.

The manufacturing method for the base material layer 622 of the elastic member 624 is not particularly limited and can be selected appropriately depending on the purpose.

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, and the prepolymer is crosslinked in a specified mold. The crosslinked product is then centrifuged into a sheet, which is then left to mature at room temperature and cut into a flat plate of specified dimensions to produce the base layer 622 of the elastic member 624.

The polyol compound is not particularly limited and can be selected appropriately depending on the purpose. Examples of polyol compounds include high molecular weight polyols and low molecular weight polyols.

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

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, and 4,4'-diaminodiphenylmethane; and 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, and pentaerythritol. These may be used alone or in combination of two or more.

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

The curing catalyst is not particularly limited and can be selected appropriately depending on the purpose. Examples include 2-methylimidazole, 1,2-dimethylimidazole, etc.

The content of the curing catalyst is not particularly limited and can be selected appropriately depending on the purpose, but is preferably 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.

The JIS-A hardness of the substrate layer 622 is not particularly limited and can be selected appropriately depending on the purpose, but is preferably 60 degrees or higher, and more preferably 65 degrees or higher and 80 degrees or lower. If the JIS-A hardness is 60 degrees or higher, blade line pressure is easily achieved and the area of contact with the photosensitive member is less likely to expand, making cleaning defects less likely to occur.

Here, the JIS-A hardness of the base layer 622 can be measured using, for example, a hardness tester (Micro Rubber Hardness Tester MD-1, manufactured by Kobunshi Keiki Co., Ltd.).

The rebound resilience of the base layer 622 is not particularly limited and can be selected appropriately depending on the purpose. Here, the rebound resilience of the base layer 622 can be measured, for example, in accordance with JIS K6255 standard at 23°C using a Toyo Seiki Seisakusho No. 221 resilience tester.

The average thickness of the base layer 622 is not particularly limited and can be selected appropriately depending on the purpose, but is preferably 1.0 mm or more and 3.0 mm or less.

<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 the other end having a free end of a predetermined length. The cleaning blade 62 is arranged so that a contact portion including a leading edge portion, which is one end of the free end side of the elastic member 624, contacts the surface of the member to be cleaned along the longitudinal direction.

The shape, size, material, etc. of the support member 621 are not particularly limited as long as they are capable of supporting the elastic member 624, and can be selected appropriately depending on the purpose. Examples of the shape of the support member 621 include flat plates, strips, and sheets. The size of the support member 621 can be selected appropriately depending on the size of the member to be cleaned.

Examples of materials for the support member 621 include metal, plastic, and ceramic. Among these, metal plates are preferred from the standpoint of strength, with steel plates such as stainless steel, aluminum plates, and phosphor bronze plates being particularly preferred.

<Photoreceptor>
Next, the photoconductor in the image forming apparatus of this embodiment will be described. First, the layer structure of the photoconductor 3 will be described.

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 contains 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 power of 35% or more and less than 45%.

The photoreceptor 3 has a conductive support 91, a photosensitive layer 92, and a surface layer 93, and may be optionally combined with other layers.

Note that photoreceptor 3 is an example of a photoreceptor (cleaned member) that constitutes part of the image forming apparatus according to this embodiment. Photoreceptor 3 is also an example of a photoreceptor according to this embodiment.

Figure 10 shows 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. Figure 11 shows an example of a photoreceptor in which a photosensitive layer 92 consisting of a charge generation layer 921 and a charge transport layer 922 laminated on a conductive support 91, and a surface layer 93 are provided. Figure 12 shows an example of a photoreceptor in which an undercoat layer 94 is provided on a conductive support 91, and a photosensitive layer 92 consisting of a charge generation layer 921 and a charge transport layer 922 laminated on a surface layer 93 are provided.

The conductive support 91 can be one that exhibits conductivity with a volume resistivity of 1010 Ω·cm or less.

Such conductive supports can be, for example, films or cylindrical plastic or paper coated with metal oxides by vapor deposition or sputtering. Examples of metal oxides in this case include oxides of aluminum, nickel, chromium, copper, gold, silver, platinum, tin, and indium.

The conductive support 91 can also be a tube made by forming a metal or metal plate into a bare tube using a process such as extrusion or drawing, and then surface-treating it with cutting, superfinishing, or polishing. Examples of metals that can be used in this case include aluminum, aluminum alloys, nickel, and stainless steel.

The endless nickel belt and endless stainless steel belt disclosed in Japanese Patent Laid-Open Publication No. 52-36016 can also be used as the conductive support 91.

In addition, a conductive powder dispersed in a suitable binder resin and coated on the above support can also be used as the conductive support 91. Examples of conductive powders in this case include carbon black, acetylene black, metal powders such as aluminum, nickel, iron, nichrome, copper, zinc, and silver, and metal oxide powders such as conductive tin oxide and ITO (indium tin oxide).

Binder resins that can be used at the same time 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, phenolic resin, and alkyd resin.

Such a conductive layer can be formed by dispersing the conductive powder and binder resin in an appropriate solvent, such as tetrahydrofuran, dichloromethane, methyl ethyl ketone, or toluene, and then applying the dispersion.

Furthermore, a conductive layer formed on a suitable cylindrical substrate using a heat-shrinkable tube made of a material such as polyvinyl chloride, polypropylene, polyester, polystyrene, polyvinylidene chloride, polyethylene, chlorinated rubber, or Teflon (registered trademark) containing conductive powder can also be suitably used as the conductive support 91.

Next, the photosensitive layer 92 will be described. The photosensitive layer 92 may be a single layer or a laminated layer. First, a photosensitive layer 92 having a laminated structure consisting of a charge generation layer 921 and a charge transport layer 922 will be described, as shown in Figures 11 and 12.

The charge generation layer 921 is a layer whose main component is a charge generation material. A known charge generation material can be used for the charge generation layer 921.

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

In this embodiment, azo pigments and/or phthalocyanine pigments are preferably used as the charge generation material. Among these, the azo pigment represented by the following [Chemical Formula 1] or titanyl phthalocyanine (particularly titanyl phthalocyanine having a maximum diffraction peak at a Bragg angle 2θ of at least 27.2° (±0.2°) for CuKα characteristic X-rays (wavelength 1.514 Å)) is more preferably used.

The charge generation layer 921 is formed by dispersing the charge generation material, along with a binder resin if necessary, in an appropriate solvent using a ball mill, attritor, sand mill, ultrasonic wave, etc., and then applying the dispersion to the conductive support 91 and drying it.

Examples of binder resins that may be used in the charge generating layer 921 if necessary 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.

The amount of binder resin is not particularly limited, and can be 0 to 500% by weight, preferably 10 to 300% by weight, relative to 100% by weight of the charge-generating material.

Solvents that can be used here include, for example, isopropanol, acetone, methyl ethyl ketone, cyclohexanone, tetrahydrofuran, dioxane, ethyl cellosolve, ethyl acetate, methyl acetate, dichloromethane, dichloroethane, monochlorobenzene, cyclohexane, toluene, xylene, and ligroin. Among these, ketone-based solvents, ester-based solvents, and ether-based solvents are preferred.

Methods that can be used to apply the coating liquid include dip coating, spray coating, bead coating, nozzle coating, spinner coating, and ring coating.

The film thickness of the charge generation layer 921 can be approximately 0.01 to 5 μm, and preferably 0.1 to 2 μm.

The charge transport layer 922 can be formed by dissolving or dispersing a charge transport material and a binder resin in an appropriate solvent, applying this to the charge generation layer 921, and drying it. If necessary, plasticizers, leveling agents, antioxidants, etc. may also be added.

Charge transport materials are divided into electron transport materials and hole transport materials.

Examples of electron transport substances include electron accepting substances 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-indeno[1,2-b]thiophen-4-one, 1,3,7-trinitrodibenzothiophene-5,5-dioxide, and benzoquinone derivatives.

Examples of hole-transporting materials include poly-N-vinylcarbazole and its derivatives, poly-γ-carbazolylethyl glutamate and its derivatives, pyrene-formaldehyde condensates and its 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, bisstilbene derivatives, and enamine derivatives.

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

Examples of binder resins include thermoplastic 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, polyarates, phenoxy resins, polycarbonates, cellulose acetate resins, ethyl cellulose resins, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly-N-vinylcarbazole, acrylic resins, silicone resins, epoxy resins, melamine resins, urethane resins, phenolic resins, and alkyd resins.

The amount of charge transport material is not particularly limited, but can be 20 to 300% by weight, preferably 40 to 150% by weight, relative to 100% by weight of the binder resin.

The thickness of the charge transport layer 922 is not particularly limited, but is preferably 30 μm or less from the standpoint 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.

Solvents used here include, for example, tetrahydrofuran, dioxane, toluene, dichloromethane, monochlorobenzene, dichloroethane, cyclohexanone, methyl ethyl ketone, and acetone.

In the photoreceptor of this embodiment, a plasticizer or leveling agent may be added to the charge transport layer 922. Plasticizers that are commonly used as plasticizers for resins, such as dibutyl phthalate and dioctyl phthalate, can be used as they are, and the amount used is approximately 0 to 30% by weight of the binder resin.

Examples of leveling agents that can be used include silicone oils such as dimethyl silicone oil and methylphenyl silicone oil, and polymers and oligomers with perfluoroalkyl groups on the side chains. The appropriate amount used is 0 to 1% by mass of the binder resin.

Next, we will explain the case where the photosensitive layer 92 has a single-layer structure, as shown in Figure 10.

The photosensitive layer 92 can be a photoreceptor in which the charge-generating material described above is dispersed in a binder resin. A single-layer photosensitive layer 92 is formed by dissolving or dispersing the charge-generating material, charge-transport material, and binder resin in an appropriate solvent, applying the solution, and drying it.

If necessary, plasticizers, leveling agents, antioxidants, etc. can also be added to the photosensitive layer 92. As the binder resin, the binder resins listed above for the charge transport layer 922 can be used as is, or they can be mixed with the binder resins listed for the charge generation layer.

The amount of charge generating material is preferably 5 to 40% by weight, and the amount of charge transport material is preferably 0 to 190% by weight, and more preferably 50 to 150% by weight, relative to 100% by weight of binder resin.

The single-layer photosensitive layer 92 can be formed by dispersing a charge-generating material, a binder resin, and other solvents such as tetrahydrofuran, dioxane, dichloroethane, or cyclohexane in a disperser or other device, and then applying the resulting coating solution by dip coating, spray coating, bead coating, or other methods.

The film thickness of the single-layer photosensitive layer 92 is preferably approximately 5 to 35 μm.

Furthermore, in the photoreceptor of this embodiment, as shown in FIG. 12, an undercoat layer 94 can be provided between the conductive support 91 and the photosensitive layer 92. The undercoat layer 94 is usually composed primarily of a resin, but considering that the photosensitive layer 92 will be applied onto the resin using a solvent, it is desirable for the resin to be highly resistant to ordinary organic solvents.

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.

Fine powder pigments of metal oxides such as titanium oxide, silica, alumina, zirconium oxide, tin oxide, and indium oxide may also be added to the undercoat layer 94 to prevent moire and reduce residual potential.

The undercoat layer 94 can be formed using an appropriate solvent and coating method, as with the photosensitive layer 92 described above. Furthermore, in this embodiment, a silane coupling agent, a titanium coupling agent, a chromium coupling agent, or the like can also be used as the undercoat layer 94.

Alternatively, the undercoat layer 94 may be formed by anodizing Al ₂ O ₃ , or by forming an organic material such as polyparaxylylene (parylene) or an inorganic material such as SiO ₂ , SnO ₂ , TiO ₂ , ITO, or CeO ₂ using a vacuum thin film deposition method. Other known materials may also be used for the undercoat layer 94.

There are no particular restrictions on the thickness of the undercoat layer 94, but it is preferably 0 to 5 μm.

In the photoreceptor 3 of this embodiment, a surface layer 93 having a binder resin and particles, a 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%, is laminated on a single-layer or multi-layer photosensitive layer 92.

The surface layer 93 of the photoreceptor 3 used in this embodiment is coated with a coating liquid 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 power of 35% or more and less than 45%.

The surface layer 93 is composed of at least particles and a binder resin. Examples of binder resins that can be used include thermoplastic resins such as polyarylate resin and polycarbonate resin, and cross-linked resins such as urethane resin and phenol resin.

The particles used can be organic or inorganic.

Examples of organic particles include fluorine-containing resin particles and diamond particles.

Examples of 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, antimony-doped tin oxide, and tin-doped indium oxide; and inorganic materials such as potassium titanate. Among these, oxides are preferred as inorganic particles, with silicon oxide, aluminum oxide, and titanium oxide being more preferred.

A higher concentration of inorganic particles in the surface layer 93 is preferable in that it increases abrasion resistance, but if it is too high, side effects such as an increase in residual potential and a decrease in the write light transmittance of the protective layer may occur. Therefore, the concentration of inorganic particles in the surface layer 93 is approximately 50% by mass or less, and preferably 30% by weight or less, based on the total solids content. There is no particular lower limit for the concentration of inorganic particles in the surface layer 93, but it is typically 5% by weight.

These inorganic particles can also be surface-treated with at least one surface treatment agent. Surface-treating the inorganic particles in this manner is preferable in terms of the dispersibility of the inorganic particles.

A decrease in the dispersibility of inorganic particles not only increases the residual potential, but also reduces the transparency of the coating film, causes coating defects, and even reduces abrasion resistance, which can potentially develop into a major problem that hinders the achievement of high durability or high image quality.

Conventional surface treatment agents can be used, but surface treatment agents that can maintain the insulating properties of inorganic particles are preferred.

As such surface treatment agents, for example, titanate-based coupling agents, aluminum-based coupling agents, zircoaluminate-based coupling agents, higher fatty acids, etc., or mixtures of these with silane coupling agents, or Al ₂ O ₃ , TiO ₂ , ZrO ₂ , silicone, aluminum stearate, etc., or mixtures of these, are more preferred in terms of dispersibility of inorganic particles and image blurring.

Treatment with a silane coupling agent can result in increased image blurring, but this effect can sometimes be reduced by mixing the above-mentioned surface treatment agent with a silane coupling agent.

The amount of surface treatment varies depending on the average primary particle size of the inorganic particles used, but an appropriate amount is approximately 3 to 30 wt%, and preferably 5 to 20 wt%. If the amount of surface treatment is too small, the inorganic particles will not be dispersed effectively, and if it is too large, it may cause a significant increase in residual potential.

These inorganic particles may be used alone or in combination of two or more types.

There are no particular restrictions on the thickness of the surface layer 93, but it is preferable that it be in the range of 1.0 to 8.0 μm.

Photoconductors that are used repeatedly over long periods of time are designed to be highly mechanically durable and resistant to wear. However, in actual equipment, ozone and NOx gases are generated from charging members and other components, and these 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.

Therefore, when considering long-term repeated use, it is preferable that the surface layer 93 have a film thickness of at least 1.0 μm or more.

Furthermore, if the thickness of the surface layer 93 is greater than 8.0 μm, there is a possibility of an increase in residual potential and a decrease in fine dot reproducibility. These inorganic particles can be dispersed using an appropriate disperser.

In addition, from the perspective of the transmittance of the surface layer 93, the average particle size of the inorganic particles in the dispersion liquid is preferably 1 μm or less, and more preferably 0.5 μm or less.

Methods for providing the surface layer 93 on the photosensitive layer 92 include, for example, dip coating, ring coating, and spray coating. Among these, a common method for forming the surface layer 93 is spray coating, in which paint is ejected from a nozzle with a microscopic opening, atomized, and the resulting microdroplets are deposited on the photosensitive layer 92 to form a coating.

Solvents used here include, for example, tetrahydrofuran, dioxane, toluene, dichloromethane, monochlorobenzene, dichloroethane, cyclohexanone, methyl ethyl ketone, and acetone.

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

When a low-molecular-weight charge transport material is used as the charge transport material, a concentration gradient may be present in the surface layer 93.

In addition, polymeric charge transport materials that function as both a charge transport material and a binder resin are also preferably used for the surface layer 93. Surface layers 93 made of these polymeric charge transport materials have excellent abrasion resistance.

While known materials can be used as polymeric charge transport materials, 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 preferred.

The surface layer 93 of the photoreceptor 3 has a hardness of 150 N/ ^mm2 or more and less than 180 N/ ^mm2 in Martens hardness, and an elastic power (We/Wt value) of 35% or more and less than 45%. Here, the Martens hardness and the elastic power are measured under the following conditions.

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

If the Martens hardness is less than 150 N/ ^mm2 , the toner may adhere to the surface of the photoreceptor, and if it is 180 N/ ^mm2 or more, local wear of the cleaning blade used in this embodiment increases.

Furthermore, if the elastic power (We/Wt value) is less than 35%, the photosensitive member wear speed will change when the image area ratio changes in the axial direction of the photosensitive member, making it more likely that uneven wear will occur. If it is 45% or higher, the cleaning performance of the cleaning blade 62 when cleaning toner remaining on the photosensitive member may decrease.

For this reason, hardness and elastic power are controlled by the amount of inorganic particles added and the type of resin. The hardness and elastic power of resins such as polycarbonate and polyarylate can be improved by incorporating a rigid structure into the resin skeleton. Furthermore, the use of polymeric charge transport materials can improve hardness and elastic power.

The coefficient of friction of the photoreceptor 3 is not particularly limited and can be selected appropriately depending on the purpose, but preferably the surface coefficient of friction measured by the Euler belt method is 0.2 or higher. The Euler belt method is a method for measuring the coefficient of friction between paper and a photoreceptor, and is described, for example, in paragraph 0023 of JP 2010-134398 A. Specifically, the coefficient of friction of the photoreceptor surface is measured using the measuring device shown in Figure 13.

In the measurement device based on the Euler belt method shown in Figure 13, the belt 140 is made from a 30 mm x 250 mm piece of medium-weight fine paper (#6200 paper (T-grain)). Hooks 140a and 140b are attached to both ends of the belt 140. A load (e.g., a load weighing 100 g) 141 is attached to hook 140a, and a digital force gauge 142 is installed on hook 140b. A cylindrical photosensitive element 143 is then fixed to a support base 144.

In the measuring device shown in Figure 13, the digital force gauge 42 is pulled in the 90° direction, and the value F is read when the belt 40 begins to move. This is then substituted into the following equation (1) to calculate the photoreceptor surface friction coefficient μ.

μ=ln(F/W)/(π/2)...(1)
however,
F: Value indicated by the digital force gauge W: Load (100g in this experiment)
π: The constant of the circumference of a circle.

As described above, the image forming apparatus of this embodiment includes the photoreceptor 3 having a surface layer 93 with a 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%, and the cleaning blade 62 having a domain having a polysiloxane structure with an average dispersed diameter of 0.1 μm or more and 5.0 μm or less in a region from the surface including the tip ridge portion 62 c of the elastic member 624 to a depth of 100 μm.

With this configuration, the image forming device of this embodiment can prevent abnormal wear of the photosensitive element and cleaning blade, and prevent curling of the cleaning blade's leading edge. Furthermore, the image forming device of this embodiment can maintain good cleaning performance over the long term by improving the ability of the cleaning blade's leading edge to follow the photosensitive element.

Furthermore, in the image forming apparatus of this embodiment, as described above, the Martens hardness of the elastic member 624 of the cleaning blade 62 measured under a load of 1000 μN from the side of the surface layer 623 at a position 20 μm inward from the tip ridge portion 62 c of the cleaning blade 62 is 0.3 N/ ^mm2 or more and 8.0 N/ ^mm2 or less.

With this configuration, in the image forming device of this embodiment, the leading edge 62c of the cleaning blade 62 is less likely to deform, and curling of the leading edge 62c is further suppressed, while chipping of the blade leading edge can be further suppressed.

Furthermore, as described above, the image forming apparatus of this embodiment has a lubricant application device 10 (lubricant application unit) that applies lubricant to the surface of the photoreceptor 3, which allows the surface of the photoreceptor 3 to maintain a low coefficient of friction even when it wears.

Furthermore, in the image forming device of this embodiment, as described above, by setting the coefficient of friction of the surface of the photoreceptor 3, measured by the Euler belt method, to 0.2 or more, it becomes easier to obtain blade line pressure while suppressing curling of the leading edge portion 62c of the cleaning blade 62. As a result, cleaning defects are less likely to occur in the image forming device of this embodiment.

As described above, the cleaning blade of this embodiment has domains with polysiloxane structures having an average dispersion diameter of 0.1 μm or more and 5.0 μm or less in a region extending to a depth of 100 μm from the surface, including the tip ridge portion 62c of the elastic member 624. This configuration allows the cleaning blade of this embodiment to achieve the same effects as the cleaning blade that constitutes part of the image forming device described above.

Specifically, the cleaning blade of this embodiment can suppress abnormal wear of the photosensitive element and cleaning blade, and the occurrence of curling of the cleaning blade's leading edge. Furthermore, the cleaning blade of this embodiment can maintain good cleaning performance over the long term by improving the ability of the cleaning blade's leading edge to follow the photosensitive element.

Furthermore, as described above, in the cleaning blade of this embodiment, the Martens hardness of the elastic member 624 measured under a load of 1000 μN from the surface layer 623 side at a position 20 μm inward from the tip ridge 62 c is 0.3 N/mm ² or more and 8.0 N/mm ² or less. With this configuration, the cleaning blade of this embodiment can achieve the same effects as those achieved by the cleaning blade that constitutes a part of the above-mentioned image forming apparatus.

Specifically, in the cleaning blade of this embodiment, the leading edge 62c of the cleaning blade 62 is less likely to deform, which further reduces curling of the leading edge 62c and chipping of the blade tip.

As described above, the photoreceptor of this embodiment has a surface layer 93 with a 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%. With this configuration, the photoreceptor of this embodiment can directly achieve the same effects as those of the photoreceptor constituting a part of the image forming apparatus described above.

Specifically, the photoreceptor of this embodiment can suppress abnormal wear of the photoreceptor and cleaning blade, and the occurrence of curling of the cleaning blade's leading edge. Furthermore, the photoreceptor of this embodiment can improve the ability of the cleaning blade's leading edge to follow the photoreceptor, maintaining good cleaning performance over the long term.

Furthermore, as described above, the photoreceptor of this embodiment achieves the same effects as those of the photoreceptor constituting part of the image forming apparatus described above by setting the coefficient of friction of the surface of the photoreceptor 3, measured by the Euler belt method, to 0.2 or more. Specifically, the photoreceptor of this embodiment makes it easier to obtain blade line pressure while suppressing curling of the leading edge portion 62c of the cleaning blade 62.

The present invention will be explained 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 weight unless otherwise specified.

<Test specimen (elastic member)>
An elastic member having a base layer and a surface layer was prepared as a test specimen. The base layer of the elastic member was prepared by centrifugal molding of a urethane rubber having the following JIS-A hardness, 23°C rebound resilience, and Martens hardness (HM).
JIS-A hardness: 75°
23°C rebound resilience: 45%
Martens hardness (HM): 0.9 N/mm ²

The methods for measuring JIS-A hardness, 23°C rebound resilience, and Martens hardness (HM) are shown below.

<<JIS-A hardness of base layer>>
The JIS-A hardness of the lower surface side of the base material layer of the elastic member was measured at 23° C. using a hardness tester (Micro Rubber Hardness Tester MD-1, manufactured by Kobunshi Keiki Co., Ltd.) in accordance with JIS K6253.

<<Rebound resilience of base layer>>
The rebound resilience of the base material layer of the elastic member was measured at 23° C. in accordance with JIS K6255 using a rebound resilience tester (No. 221 Resilience Tester, manufactured by Toyo Seiki Seisaku-sho, Ltd.) The sample used was two 2 mm thick sheets stacked together to give a thickness of 4 mm or more.

<<Martens hardness of base layer>>
The Martens hardness of the substrate layer of the elastic member was measured using the aforementioned hardness tester (Fisher Instruments, Microhardness Tester HM-2000).

<Surface layer formation>
The materials used in the curable composition for forming the surface layer are shown below.

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

[Polyol]
PTMG (Polytetramethylene ether glycol): Mitsubishi Chemical, PTMG1000
PCL (polycaprolactone diol): Daicel, Plaxel (registered trademark) 220

[Curing agent]
DETDA (diethyltoluenediamine): Ethacure (registered trademark) 100, manufactured by Mitsui Fine Chemicals, Inc.
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

[Siloxane-based compounds]
- One-terminated carbinol-modified silicone oil: Shin-Etsu Silicone, X-22-176DX
- Both-end carbinol-modified silicone oil: Shin-Etsu Silicone, KF6000
Dimethyl silicone oil: Shin-Etsu Silicone, KF96-3000cs

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

In Table 1, "176-DX" refers to X-22-176DX.

[Synthesis of NCO-Terminated Urethane Prepolymer (Prepolymer B)]
As shown in Table 2 below, isocyanate and polyol were mixed so as to obtain the desired NCO percentage, 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.

In Table 2, "PCL220" stands for Plaxel 220.

[Preparation of Curing Agent]
Curing agents 1 to 3 were prepared as shown in Table 3 below.

<Preparation 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.

Curing agent 1 was added to the first composition, which contained an emulsified silicone oil and was heated to 80°C. This mixture was allowed to react for 30 minutes in a centrifugal drum heated to 125°C (the 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.

A portion of the obtained rubber sheet was cut into a strip shape suitable for installation in a color printer (RICOH Pro C9110, manufactured by Ricoh Co., Ltd.) and fixed to a sheet metal holder (support member) with adhesive. In this way, cleaning blade 1 was produced, which had an elastic member with a surface layer formed on the contact portion. The rubber sheet was cut with the surface layer facing downwards so that the razor blade would contact the base layer side.

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

In Table 4, KF96 indicates KF96-3000cs.

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

<Average Dispersion Diameter of Domains Having Polysiloxane Structure>
The prepared elastic member was sliced into rings perpendicular to the longitudinal direction, and the cross section was placed facing upward, and a 100 μm region including the tip ridge was observed using a laser microscope (OLS4100, manufactured by Olympus Corporation). The elastic member was sliced into rings by cutting perpendicular to the longitudinal direction of the elastic member using a razor so that the thickness of the elastic member in the longitudinal direction was 3 mm. Using a vertical slicer allowed for a cleaner cut.

The average dispersion diameter of the domains was measured for the observed images using ImagePro ver. 5.1. The length of a line segment connecting two points on the periphery of the domain observed in the cross section and passing through the center of gravity of the domain was measured in increments of 2 degrees. The average length of the measured line segment was taken as the dispersion diameter of that domain. The dispersion diameters of 100 to 200 domains were measured, and the number-average value was calculated, which was taken as the average dispersion diameter.

<Martens hardness of cleaning blade>
The Martens hardness (HM) of the cleaning blade on the lower surface thereof was measured using a hardness tester (Fisher Instruments, Microhardness Tester HM-2000) by pressing a Vickers indenter with a force of 1.0 mN for 10 seconds, holding the indenter for 5 seconds, and then removing the indenter with a force of 1.0 mN for 10 seconds.

The measurement was performed 20 μm from the tip ridge of the underside of the blade, with the Vickers indenter in contact with the surface layer. The measurement was performed at a location excluding 2 cm sections on both ends.

<Assembly of Image Forming Apparatus>
The prepared blades 1 to 9 were attached to a color printer (RICOH Pro C9110, manufactured by Ricoh Co., Ltd.) to assemble an image forming apparatus. The cleaning blade was attached to the image forming apparatus so that the linear pressure was 20 g/cm and the cleaning angle was 79°.

<Preparation of Photoreceptor>
Photoreceptors 1 to 8 were prepared under the following conditions.

<Photoreceptor 1>
[Support]
An aluminum support (outer diameter 100 mm) was used as a blank tube.

[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.

(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: CR-EL, manufactured by Ishihara Sangyo Kaisha
Methyl ethyl ketone (mass ratio): alkyd resin/melamine resin/titanium oxide/methyl ethyl ketone = 3/2/20/100

[Charge Generation Layer]
A charge generating layer coating liquid containing titanyl fluorocyanine 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.

(Charge generation layer coating liquid)
Titanyl nitrile cyanine polyvinyl butyral (XYHL:UCC)
2-butanone (mass ratio): titanyl nitrile/polyvinyl butyral/2-butanone = 8/5/400

Figure 14 shows an example of the powder X-ray diffraction spectrum of the titanyl phthalocyanine used.

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

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

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

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

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

(Surface layer coating liquid 2)
Charge transport material of the formula (3): 7.5 parts; Binder resin of bisphenol Z type polycarbonate (manufactured by Teijin Chemicals, Ltd., Panlite (registered trademark) TS-2040): 2 parts; Binder resin of bisphenol Z type polycarbonate (manufactured by Teijin Chemicals, Ltd., Panlite (registered trademark) TS-2050): 8 parts; Additive (manufactured by BASF Japan, Ltd., Irganox 1076): 1 part; Fluorine particles (manufactured by DuPont-Mitsui Fluorochemicals, MPE-056): 2 parts; Tetrahydrofuran: 400 parts

<Photoreceptor 3>
Photoreceptor 3 was obtained in the same manner as for photoreceptor 1, except that surface layer coating liquid 3 below was used.

(Surface layer coating liquid 3)
Charge transport material of the above [Chemical Formula 3]: 8 parts; Bisphenol Z type polycarbonate binder resin (Teijin Chemical Co., Ltd., Panlite (registered trademark) TS-2050): 5 parts; Bisphenol Z type polycarbonate binder resin (Teijin Chemical Co., Ltd., Panlite (registered trademark) TS-2080): 5 parts; Additive (BASF Japan Ltd., Irganox 1076): 1 part; Alumina particles (AA03: Sumitomo Chemical Co., Ltd.): 2 parts; Tetrahydrofuran: 500 parts

<Photoreceptor 4>
Photoreceptor 4 was obtained in the same manner as for photoreceptor 1, except that surface layer coating liquid 4 below was used.

(Surface layer coating liquid 4)
Charge transport material of the above [Chemical Formula 3]: 7.5 parts Bisphenol Z type polycarbonate binder resin (Teijin Chemical Co., Ltd., Panlite (registered trademark) TS-2050): 5 parts Bisphenol Z type polycarbonate binder resin (Teijin Chemical Co., Ltd., Panlite (registered trademark) TS-2080): 5 parts Additive (BASF Japan Ltd., Irganox 1076): 1.5 parts Alumina particles (AA03: Sumitomo Chemical Co., Ltd.): 2 parts Tetrahydrofuran: 500 parts

<Photoreceptor 5>
Photoreceptor 5 was obtained in the same manner as in Photoreceptor 1 except that Surface Layer Coating Solution 5 below was used.

(Surface layer coating liquid 5)
Charge transport material of the formula (3): 7 parts; Bisphenol Z-type polycarbonate binder resin (Teijin Chemical Co., Ltd., Panlite (registered trademark) TS-2050): 5 parts; Bisphenol Z-type polycarbonate binder resin (Teijin Chemical Co., Ltd., Panlite (registered trademark) TS-2080): 5 parts; Additive (BASF Japan, Irganox 1076): 1.5 parts; Alumina particles (AA03: Sumitomo Chemical Co., Ltd.): 2 parts; Silicone oil (Shin-Etsu Chemical Co., Ltd., KF-50-100CS): 0.005 parts; Tetrahydrofuran: 500 parts

<Photoreceptor 6>
Photoreceptor 6 was obtained in the same manner as for photoreceptor 1, except that surface layer coating liquid 6 below was used.

(Surface layer coating liquid 6)
Charge transport material of the formula (3): 6.5 parts; Binder resin of bisphenol Z-type polycarbonate (Teijin Chemical Co., Ltd., Panlite (registered trademark) TS-2040): 2 parts; Binder resin of bisphenol Z-type polycarbonate (Teijin Chemical Co., Ltd., Panlite (registered trademark) TS-2050): 8 parts; Additive (BASF Japan, Irganox 1076): 1.5 parts; Fluorine particles (Mitsui DuPont Fluorochemicals, MPE-056): 2 parts; Silicone oil (Shin-Etsu Chemical Co., Ltd., KF-50-100CS): 0.005 parts; Tetrahydrofuran: 400 parts

<Photoreceptor 7>
Photoreceptor 7 was obtained in the same manner as in Photoreceptor 1 except that Surface Layer Coating Solution 7 below was used.

(Surface layer coating liquid 7)
Charge transport material of the formula (3): 7 parts; Bisphenol Z-type polycarbonate binder resin (Teijin Chemical Co., Ltd., Panlite (registered trademark) TS-2040): 10 parts; Additive (BASF Japan Ltd., Irganox 1076): 1.5 parts; Alumina particles (AA03: Sumitomo Chemical Co., Ltd.): 2 parts; Silicone oil (Shin-Etsu Chemical Co., Ltd., KF-50-100CS): 0.005 parts; Tetrahydrofuran: 400 parts

<Photoreceptor 8>
Photoreceptor 8 was obtained in the same manner as for photoreceptor 1, except that surface layer coating solution 8 below was used.

(Surface layer coating liquid 8)
Charge transport material of the formula (3): 6 parts; Binder resin of bisphenol Z-type polycarbonate (Teijin Chemical Co., Ltd., Panlite (registered trademark) TS-2050): 2 parts; Binder resin of bisphenol Z-type polycarbonate (Teijin Chemical Co., Ltd., Panlite (registered trademark) TS-2080): 8 parts; Additive (BASF Japan Ltd., Irganox 1076): 1.5 parts; Alumina particles (AA03: Sumitomo Chemical Co., Ltd.): 2 parts; Silicone oil (Shin-Etsu Chemical Co., Ltd., KF-50-100CS): 0.005 parts; Tetrahydrofuran: 550 parts

<Friction coefficient of photoreceptor>
The friction coefficient of the photoreceptor surface was measured by the Euler belt method described above.

Table 6 shows the results of measuring the surface hardness (Martens hardness), elastic power (We/Wt value), and coefficient of friction for the prepared photoreceptors 1 to 8.

Next, we will explain the configuration of the image forming device used in the verification experiment.

The above-prepared blades 1 to 9 and the above-prepared photoreceptors 1 to 8 were mounted in the combinations shown in Table 7 in a color printer (RICOH PRO C9110, manufactured by Ricoh) to produce the image forming devices of Examples 1 to 9 and Comparative Examples 1 to 4. A 400,000-sheet paper feed test was conducted with these image forming devices under the following conditions.

・Paper used: NBS Ricoh My Paper A4
Station used: Black Output image: Image area ratio 0%, 50%, 100% (Images with different image area ratios are output within the same chart.)
Lubricant application means: Only in Example 7, the mechanism was modified to not use a lubricant application means, and a verification experiment was carried out.

The following items were evaluated for Examples 1 to 9 and Comparative Examples 1 to 4 shown in Table 7.

<Cleaning failure>
Under the conditions of a vertical band pattern (in the paper travel direction) 43 mm wide and three charts, the image after outputting 20 sheets (A4 landscape) was visually inspected and the cleaning failure was evaluated according to the following evaluation criteria.
(Evaluation criteria)
Good: Not occurring. Possible: Occurs only at the edges. Unacceptable: Occurs on the entire surface.

<Observation of the blade edge>
The blade edge was visually observed using a microscope (Keyence Corporation, Digital Microscope VHX-100) and evaluated according to the following evaluation criteria.
(Evaluation criteria)
Good: No chipping or toner adhesion on the edge of the entire cleaning blade. Fair: Minor chipping or toner adhesion on the edge. Poor: Clear chipping or toner adhesion on the edge.

<Blade edge wear width>
As shown in Figure 15, the wear width as viewed from the blade tip surface was measured using a microscope (Keyence Corporation, Digital Microscope VHX-100) on the cross section of a similarly coated elastic blade. The sample was cut into a cross section using a trimming razor for SEM sample preparation manufactured by Nissin EM. The wear width of the blade edge was evaluated according to the following criteria.
(Evaluation criteria)
Good: Wear width less than 50 μm Acceptable: Wear width 50 μm or more but less than 100 μm Unacceptable: Wear width 100 μm or more

<Observation of the surface of the photoreceptor>
The results were evaluated visually and using a real color confocal microscope OPTELICS H1200 manufactured by Lasertec Corporation according to the following evaluation criteria.
(Evaluation criteria)
Good: No scratches or toner adhesions on the entire surface of the photoconductor. Fair: Minor scratches or toner adhesions on part of the surface of the photoconductor. Poor: Clear scratches or toner adhesions on the entire surface of the photoconductor. Photoconductor wear evaluation

<Photoreceptor Film Thickness Reduction>
The film thickness at any five points in the area where the image area was continuously output at 0%, 50%, and 100% was measured using an eddy current film thickness meter (Fisherscope (registered trademark) MMS, manufactured by Fisher Instruments) to show the amount of film thickness reduction from the initial value.
Good: The film thickness reduction is less than 1 μm. Acceptable: The film thickness reduction is 1 μm or more but less than 3 μm. Unacceptable: The film thickness reduction is 3 μm or more.

The results are shown in Table 8.

Table 8 shows that Examples 1 to 9 maintained good cleaning performance over a long period of time, and were able to suppress abnormal wear of the photoreceptor and cleaning blade, as well as curling of the ridge at the tip of the cleaning blade.

On the other hand, in Comparative Examples 1 to 4, poor results were obtained in the cleaning evaluation, and abnormal wear was observed.

Although the above describes an embodiment of the present invention, the present invention is not limited to a specific embodiment, and various modifications and variations are possible within the scope of the invention described in the claims.

1 Imaging unit (process cartridge)
2 Frame 3 Photosensitive member 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 tip surface 62b Blade lower surface 62c Tip ridge portion 621 Support member 622 Base 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 Undercoat layer 101 Fur brush 103 Solid lubricant 140 Belt 140a, 140b Hook 141 Load 142 Digital force gauge 143 Photosensitive member 144 Support base 162 Belt cleaning unit 162a Belt cleaning blade 500 Printer 621 Support member

JP 2010-191378 A Patent No. 3602898 Japanese Patent Application Laid-Open No. 2004-233818 JP 2011-138110 A

Claims (4)

A photoreceptor;
a cleaning blade having an elastic member that comes into contact with the surface of the photoreceptor to remove deposits adhering to the surface of the photoreceptor,
The photoreceptor is
A conductive support;
a photosensitive layer and a surface layer laminated in this order on the conductive support,
the surface layer contains a polycarbonate resin as a binder resin and one of alumina particles, fluorine-containing resin particles, and silica particles as particles, and has a 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%,
The cleaning blade is
the elastic member has a base layer and a surface layer,
the surface layer has a tip ridge portion,
An image forming apparatus characterized in that the surface layer has a domain having a polysiloxane structure containing dimethyl silicone oil and having an average dispersed diameter of 0.1 μm or more and 5.0 μm or less in a region from the surface including the tip ridge portion of the elastic member to a depth of 100 μm. The cleaning blade is
2. The image forming apparatus according to claim 1, wherein the Martens hardness of the elastic member measured from the surface layer side at a position 20 μm inward from the tip ridge line portion under a load of 1000 μN is 0.3 N/ ^mm2 or more and 8.0 N/ ^mm2 or less. The image forming apparatus of claim 1 or 2, further comprising a lubricant application unit that applies a lubricant to the surface of the photoreceptor. The image forming apparatus of any one of claims 1 to 3, wherein the coefficient of friction of the surface of the photoreceptor measured by the Euler belt method is 0.2 or more.