JP2009300750A - Image forming apparatus and process cartridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus and a process cartridge which suppress the occurrence of chatter vibration and noise, extend the lifetime of an image carrier and a cleaning blade, maintain good cleaning performance for a long time period of time, and allow a good image to be obtained. <P>SOLUTION: A cleaning blade 62 includes a strip-shaped holder 621 made of a rigid material like a metal or rigid plastics and a strip-shaped elastic blade 622, and a surface layer which is harder than the elastic blade and has a friction coefficient of 0.1 to 0.6 is formed on an entire front end surface 62a of the cleaning blade 62 and around a front end ridge part 62c of a lower surface 62b so as to cover the front end ridge part 62c. A lubricant applying device 10 is disposed downstream side of a contact position where the cleaning blade is brought into contact with a photoreceptor, in a photoreceptor surface moving direction and upstream side of a developing area of a developing device in the photoreceptor surface moving direction. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

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

  2. Description of the Related Art Conventionally, in an electrophotographic image forming apparatus, unnecessary transfer residual toner adhering to a surface after transferring a toner image to a transfer paper or an intermediate transfer body is removed as a cleaning unit. Has been removed by. As a cleaning member of this cleaning device, one that uses a strip-shaped cleaning blade is well known because it can generally be simplified in configuration and has excellent cleaning performance. This cleaning blade is made of an elastic body such as polyurethane rubber. Then, the base end of the cleaning blade is supported by a support member, and the leading edge portion is pressed against the peripheral surface of the image carrier, and the toner remaining on the image carrier is damped and scraped off and removed.

  Further, in order to meet the recent demand for higher image quality, an image forming apparatus using a toner having a small particle diameter and a nearly spherical shape (hereinafter, polymerized toner) formed by a polymerization method or the like is known. This polymerized toner has characteristics such as higher transfer efficiency than conventional pulverized toner, and can meet the above requirements. However, it is difficult to remove the polymerized toner sufficiently from the surface of the image carrier using a cleaning blade, and there is a problem that cleaning failure occurs. This is because the polymerized toner having a small particle size and excellent sphericity passes through a slight gap formed between the blade and the image carrier.

  In order to suppress such slip-through, it is necessary to increase the cleaning pressure by increasing the contact pressure between the image carrier and the cleaning blade. However, when the contact pressure of the cleaning blade is increased, the frictional force between the image carrier 3 and the cleaning blade 62 increases as shown in FIG. 7A, and the cleaning blade 62 is pulled in the moving direction of the image carrier 3. As a result, the tip edge line portion 62c of the cleaning blade 62 is turned over. When the turned cleaning blade 62 is restored to its original state against the turn, abnormal noise may occur. In addition, chatter vibration is generated by repeating this turning and restoration. Further, when the cleaning is continued with the leading edge portion 62c of the cleaning blade 62 turned up, as shown in FIG. 7B, the cleaning blade 62 is separated from the leading edge portion 62c of the leading edge surface 62b by several [μm]. Local wear will occur at the location. If the cleaning is further continued in such a state, the local wear increases, and the leading edge portion 62c is lost as shown in FIG. 7C. If the leading edge portion 62c is missing, the toner cannot be properly cleaned, resulting in poor cleaning.

  Patent Document 1 describes that a cleaning blade made of polyurethane elastomer is provided with a surface layer made of a resin having a film hardness of pencil hardness B to 6H on at least the contact portion. By setting the pencil hardness of the resin to B or higher, the friction coefficient of the cleaning blade contact portion can be lowered, the wear resistance of the cleaning blade can be increased, and the tip ridge portion of the cleaning blade can be prevented from being turned up. can do.

Japanese Patent No. 3602898

However, since the surface layer made of a resin harder than the rubber member of Patent Document 1 cannot be flexibly deformed like the rubber member, the surface layer of the surface layer when the tip ridge line portion of the cleaning blade is brought into contact with the surface of the photoreceptor. Stress concentrates near the edge of the tip. As a result, fine cracks will occur in the portion over time. When such fine cracks occur, good cleaning properties cannot be maintained.
In addition, since the surface layer harder than the rubber member contacts the surface of the image carrier with high contact pressure, the surface of the image carrier is worn out earlier than when the rubber blade is in contact with the image carrier. There was also a problem that the function of the carrier was lowered, and image quality deterioration such as background stains occurred at an early stage.

  As described in Japanese Patent Application No. 2008-68665, the present applicant provides a lubricant application device upstream of the cleaning blade contact position in the photosensitive member moving direction and downstream of the transfer position. It has been found that the cleaning performance can be maintained even if fine cracks occur in the surface layer by applying the lubricant to the surface of the body and supplying the lubricant to the contact position between the cleaning blade and the photoreceptor surface. It was. Further, by applying a lubricant to the surface of the photoconductor, the coefficient of friction of the photoconductor can be lowered, and wear and filming of the photoconductor can be suppressed.

  However, as in the image forming apparatus described in Japanese Patent Application No. 2008-68665, if a lubricant application device is provided upstream of the cleaning blade contact position in the photosensitive member moving direction and downstream of the transfer position, It was found that the following problems occur. That is, when a lubricant application device is provided upstream of the cleaning blade contact position in the direction of movement of the photosensitive member and downstream of the transfer position, the lubricant is applied onto the transfer toner adhered to the surface of the photosensitive member. It becomes. As a result, when the transfer residual toner is removed by the cleaning blade, the lubricant is also removed, and the amount of lubricant on the surface of the photoreceptor after passing through the cleaning blade corresponding to the location where a large amount of transfer residual toner has adhered is obtained. Therefore, the amount of lubricant on the surface of the photoconductor after passing through the cleaning blade corresponding to the place where the toner remaining after transfer is not much attached becomes smaller, and the amount of lubricant on the surface of the photoconductor after passing through the cleaning blade is biased. As a result, the adhesion force between the toner and the surface of the photosensitive member, which is adhered to the surface of the photosensitive member by the developing unit, and the toner and the surface of the photosensitive member, which are adhered to the portion of the surface of the photosensitive member by the developing unit that are less This is a defect that causes various abnormal images such as transfer unevenness, character missing, bug eater, image blur, and blur.

  Furthermore, the transfer residual toner adheres to the application brush for applying the lubricant to the surface of the photoreceptor of the lubricant application device, and the application brush becomes dirty, making it impossible to apply the lubricant uniformly on the surface of the photoreceptor over time. End up. As a result, sufficient lubricant cannot be supplied to a part of the contact portion between the cleaning blade and the surface of the photosensitive member in the axial direction, and toner slips through the portion, resulting in poor cleaning.

  The present invention has been made in view of the above problems, and its purpose is to suppress chatter vibration and abnormal noise, improve the life of the image carrier and the cleaning blade, and maintain good cleaning properties over time. And providing an image forming apparatus and a process cartridge capable of obtaining a good image.

To achieve the above object, the invention of claim 1 is directed to an image carrier, charging means for charging the surface of the image carrier, and latent image formation for forming an electrostatic latent image on the charged surface of the image carrier. Developing means for developing the electrostatic latent image formed on the surface of the image carrier into a toner image, transfer means for transferring the toner image on the surface of the image carrier to a transfer body, and the image carrier In an image forming apparatus comprising a cleaning unit having a cleaning blade that contacts a body surface and cleans transfer residual toner attached to the surface of the image carrier, the cleaning blade includes a strip-shaped elastic blade, Covering the tip ridge line portion of the elastic blade, having a surface layer that is harder than the elastic blade and has a friction coefficient of 0.1 to 0.6, and is in contact with the image carrier of the cleaning blade Lubricant application means for applying a lubricant to the surface of the image carrier on the downstream side in the moving direction of the image carrier from the contact position and on the upstream side of the development area of the developing means in the direction of movement of the image carrier. It is characterized by the arrangement.
According to a second aspect of the present invention, in the image forming apparatus of the first aspect, the surface layer has a pencil hardness of 7 [H] or more.
According to a third aspect of the present invention, in the image forming apparatus of the first or second aspect, a rubber containing a urethane group is used as the elastic blade.
According to a fourth aspect of the present invention, in the image forming apparatus according to any one of the first to third aspects, the lubricant application unit includes a lubricant supply unit that supplies a lubricant to the surface of the image carrier, and the lubricant supply. And a lubricant leveling means for leveling the lubricant supplied to the surface of the image carrier by the means.
According to a fifth aspect of the present invention, in the image forming apparatus of the fourth aspect, a blade member is used as the lubricant leveling means.
According to a sixth aspect of the present invention, in the image forming apparatus of the fourth or fifth aspect, the lubricant is a solid lubricant, and the solid lubricant is scraped off while rotating as the lubricant supply means. The present invention is characterized in that a roller-shaped brush for supplying to the image carrier is used.
According to a seventh aspect of the present invention, in the image forming apparatus according to any one of the first to sixth aspects, the lubricant is a metal soap, and is at least one selected from zinc stearate, aluminum stearate, and calcium stearate. It is the above metal soap.
According to an eighth aspect of the present invention, there is provided the image forming apparatus according to any one of the first to seventh aspects, wherein the image carrier, at least the cleaning unit, and the lubricant applying unit are integrally supported, with respect to the apparatus main body. And a process cartridge that is detachable.
The invention according to claim 9 integrally supports the image carrier and at least a cleaning means having a cleaning blade for cleaning the transfer residual toner adhering to the surface of the image carrier, and is detachably attached to the main body of the image forming apparatus. In this process cartridge, the cleaning blade covers a strip-shaped elastic blade and a tip ridge line portion of the elastic blade, is harder than the elastic blade, and has a friction coefficient of 0.1 to 0.6. The image carrier surface movement relative to the image carrier surface movement direction downstream from the contact position of the cleaning blade in contact with the image carrier and from the developing region of the developing means. A lubricant application unit for applying a lubricant to the surface of the image carrier is provided on the upstream side in the direction.

According to the first to ninth aspects of the present invention, as shown in the experimental results to be described later, the tip edge line portion of the cleaning blade is harder than the elastic blade and is covered with a surface layer having a friction coefficient of 0.1 to 0.6. Thus, the tip ridge line portion is not covered with the surface layer, and the wear resistance of the cleaning blade can be improved as compared with a cleaning blade made of only an elastic blade. Therefore, the lifetime of the cleaning blade can be extended. In addition, deformation of the tip ridge line portion of the cleaning blade is suppressed, and turning of the tip ridge line portion can be suppressed. Therefore, chatter vibration and abnormal noise can be suppressed, and local wear on the cleaning blade tip surface can be suppressed.
Further, the lubricant can be supplied to the contact position between the cleaning blade and the surface of the image carrier by applying the lubricant to the surface of the image carrier by the lubricant application means. Thereby, even if a fine crack occurs in the surface layer, good cleaning properties can be maintained. Further, by applying a lubricant to the surface of the photoconductor, the coefficient of friction of the photoconductor can be lowered, and wear and filming of the photoconductor can be suppressed.
Further, a lubricant application unit is provided on the downstream side of the image carrier surface movement direction with respect to the contact position of the cleaning blade with the image carrier and on the upstream side of the development region of the developing unit with respect to the image carrier surface movement direction. Thus, the lubricant applied by the lubricant applying device is not removed together with the transfer residual toner by the cleaning blade before passing through the developing area of the developing means. Accordingly, the amount of lubricant on the surface of the image carrier passing through the development area of the developing unit can be made uniform, and the adhesion force between the toner attached to the surface of the photosensitive member by the developing unit and the image carrier can be made uniform. As a result, good transferability can be obtained and a good image can be obtained.
Further, the toner hardly adheres to the surface of the image carrier from the contact position where the cleaning blade contacts the image carrier to the development area of the developing means. Therefore, by applying the lubricant in this region, it is possible to prevent the toner from adhering to the lubricant applying means, and to apply the lubricant uniformly in the axial direction over time. Thereby, a good cleaning property and a good image can be maintained over time.

Hereinafter, an embodiment in which the present invention is applied to an electrophotographic printer (hereinafter simply referred to as a printer) as an image forming apparatus will be described.
FIG. 1 is a schematic configuration diagram illustrating a main part of the printer according to the present embodiment. The printer performs single-color copying, and forms a monochrome image based on image data read by an image reading unit (not shown).

  As shown in FIG. 1, the printer includes a drum-shaped photoconductor 3 as an image carrier. The photosensitive member 3 has a drum shape, but may be a sheet shape or an endless belt shape.

  Around the photosensitive member 3, a charging charger 4 as a charging means, a developing device 5 as a developing means for converting a latent image into a toner image, a transfer device 7 as a transferring means for transferring a toner image onto a transfer sheet as a recording medium, Separation claw 8 for separating the transfer paper from the photoreceptor 3, charger 9 before cleaning for aligning the charging polarity of the toner remaining on the photoreceptor 3 after transfer, and toner remaining on the photoreceptor 3 after transfer A cleaning device 6 for cleaning, a lubricant coating device 10, a neutralizing lamp 11 for neutralizing the photosensitive member 3, and the like are arranged.

  The charging charger 4 is arranged in a non-contact manner with a predetermined distance from the photoconductor 3, and charges the photoconductor 3 to a predetermined polarity and a predetermined potential. The photosensitive member 3 uniformly charged by the charging charger 4 is irradiated with light L based on image data from an exposure device which is a latent image forming means (not shown), and an electrostatic latent image is formed.

  The developing device 5 has a developing roller 51 as a developer carrier. A developing bias is applied to the developing roller 51 from a power source (not shown). In the casing of the developing device 5, a supply screw 52 and a stirring screw 53 are provided for stirring the developer contained in the casing while conveying the developer in opposite directions. A doctor 54 for regulating the developer carried on the developing roller 51 is also provided. The toner in the developer stirred and conveyed by the two screws of the supply screw 52 and the stirring screw 53 is charged to a predetermined polarity. The developer is pumped up by the developing roller 51, and the pumped-up developer 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 transfer device 7 includes a pre-transfer charger 71, a transfer charger 72, and a separation charger 73. Negative corona discharge is performed by the pre-transfer charger 71 to align the polarity of the toner, and then the toner image is transferred onto the transfer paper under corona discharge by the transfer charger 72. The transfer paper is separated from the surface of the photosensitive member 3 by the corona discharge of the separation charger 73 and the separation claw 8.

  The cleaning device 6 includes a cleaning blade 62, a lubricant application device 10, and the like. The cleaning blade 62 is an elastic blade in which urethane rubber, silicone rubber, or the like is formed in a strip shape. It touches. The cleaning blade 62 removes transfer residual toner on the photoreceptor. Details of the cleaning blade 62 will be described later.

  The lubricant application device 10 is disposed downstream of the cleaning blade 62 in the moving direction of the photosensitive member surface. A leveling blade 110 is provided as a means for controlling. The solid lubricant 103 is obtained by dissolving a lubricant additive mainly composed of zinc stearate and then cooling and solidifying the lubricant, and is formed into a bar shape. The solid lubricant 103 is held by the bracket 105 and is pressed toward the application brush 101 by a lubricant pressurizing spring 104 attached to the case of the cleaning device 6. The coating brush 101 is provided in contact with the photosensitive member 3, and the solid lubricant 103 is scraped by rotation of the coating brush 101 in the rotating direction with respect to the rotation direction of the photosensitive member 3, and residual toner is removed by the cleaning blade 62. A lubricant is applied to the surface of the photoreceptor 3 that has been removed and is in a clean state. The lubricant applied to the photoreceptor surface by the application brush 101 is stretched by a leveling blade that rubs against the photoreceptor surface. As a result, a thin layer of lubricant is formed on the surface of the photoreceptor. In FIG. 1, the leveling blade is in contact with the photoconductor 3 in the trail direction with respect to the surface movement direction of the photoconductor 3, but may be in contact in the counter direction. Further, the supply amount of the lubricant to the photoconductor 3 can be controlled by the pressing force of the lubricant pressurizing spring 104 that presses the solid lubricant 103 against the application brush 101.

  As the solid lubricant 103, at least one metal soap selected from zinc stearate, aluminum stearate, and calcium stearate can be suitably used. It is also possible to use a dry solid hydrophobic lubricant. Besides the above, barium stearate, lead stearate, iron stearate, nickel stearate, cobalt stearate, copper stearate, strontium stearate Those having a stearic acid group such as cadmium stearate and magnesium stearate can be used. In addition, the same fatty acid groups zinc oleate, manganese oleate, iron oleate, cobalt oleate, lead oleate, magnesium oleate, copper oleate, and palmitic acid, zinc cobalt palmitate, copper palmitate, palmitate Magnesium acid, aluminum palmitate, and calcium palmitate may be used. In addition, fatty acids such as lead caprylate, lead caproate, zinc linolenate, cobalt linolenate, calcium linolenate and cadmium ricolinolenate, metal salts of fatty acids, and the like can also be used. Further, waxes such as candelilla wax, carnauba wax, rice wax, wax, ooba oil, beeswax, and lanolin can be used.

  The pre-transfer charger 71, the separation claw 8, and the pre-cleaning charger 9 are arranged as necessary.

As the charging charger 4, the pre-transfer charger 71, the transfer charger 72, the separation charger 73, and the pre-cleaning charger 9, known means such as a corotron, a scorotron, and a solid state charger are used.
Among these charging methods, the contact charging method or the non-contact proximity arrangement method is more desirable, and has advantages such as high charging efficiency, a small amount of ozone generation, and miniaturization of the apparatus.

Further, light sources such as an exposure apparatus (not shown) and a charge removal lamp 11 include a fluorescent lamp, a tungsten lamp, a halogen lamp, a mercury lamp, a sodium lamp, a light emitting diode (LED), a semiconductor laser (LD), and an electroluminescence (EL). All luminescent materials can be used.
In addition, various types of filters such as a sharp cut filter, a band pass filter, a near infrared cut filter, a dichroic filter, an interference filter, and a color temperature conversion filter can be used to irradiate only light in a desired wavelength range.
Among these light sources, light emitting diodes and semiconductor lasers are used favorably because they have high irradiation energy and long wavelength light of 600 to 800 nm.

Next, an image forming operation in the printer will be described.
When a print execution signal is received from an operation unit (not shown), a predetermined voltage or current is sequentially applied to the charging charger 4, the developing roller 51, the pre-transfer charger 71, the transfer charger 72, the separation charger 73, and the pre-cleaning charger 9, respectively. Applied at timing. Similarly, a predetermined voltage or current is sequentially applied to the exposure apparatus and the charge removal lamp 11 at predetermined timing. In synchronism with this, the photosensitive member 3 is rotationally driven in the direction of the arrow in the figure by a photosensitive member driving motor (not shown) as a driving means.

  When the photoconductor 3 rotates in the direction of the arrow in the figure, the surface of the photoconductor is first charged to a predetermined potential by the charging charger 4. Then, light L corresponding to the image signal is irradiated onto the photoconductor 3 from an exposure device (not shown), and the portion of the photoconductor 3 irradiated with the light L is neutralized to form an electrostatic latent image.

  The photosensitive member 3 on which the electrostatic latent image is formed is rubbed against the surface of the photosensitive member 3 with a magnetic brush of developer formed on the developing roller 51 at a portion facing the developing device 5. At this time, the negatively charged toner on the developing roller 51 is moved to the electrostatic latent image side by a predetermined developing bias applied to the developing roller 51 to be converted into a toner image (development). Thus, in the present embodiment, the electrostatic latent image formed on the photoreceptor 3 is reversely developed by the developing device 5 with the negatively charged toner. In this embodiment, an example using a non-contact charging roller system of N / P (negative positive: toner adheres to a place where the potential is low) has been described, but the present invention is not limited to this.

The toner image formed on the photoconductor 3 passes through a facing portion between the upper registration roller 11 and the lower registration roller 12 from a paper supply unit (not shown) to a transfer region formed between the photoconductor 1 and the transfer charger. It is transferred to the transfer paper that is fed. At this time, the transfer paper is supplied in synchronism with the leading edge of the image at the facing portion between the upper registration roller 12 and the lower registration roller 13. In addition, a predetermined transfer bias is applied during transfer onto the transfer paper. The transfer paper onto which the toner image has been transferred is separated from the photosensitive member 3 by the separation claw 8 and the separation charger 73, and is conveyed to a fixing device (not shown) as fixing means. By passing through the fixing device, the toner image is fixed on the transfer paper by the action of heat and pressure, and the transfer paper is discharged out of the apparatus.
On the other hand, the surface of the photoreceptor 3 after the transfer is subjected to removal of residual toner after the transfer by the cleaning device 6, then the lubricant is applied by the lubricant applying device 10, and the charge is removed by the charge removing lamp 11.

  Further, in this printer, a photosensitive member 3, a charging charger 4, a developing device 5, a cleaning device 6, a lubricant applying device 10 and the like as process means are housed in a frame 2, and a process cartridge 1 is provided from the main body of the device. It is detachable integrally. In this embodiment, the photosensitive member 3 as the process cartridge 1 and the process means are integrally replaced. However, the photosensitive member 3, the charging charger 4, the developing device 5, the cleaning device 6, the lubricant. The structure which replaces | exchanges for a new thing in units like the coating device 10 may be sufficient.

Next, a toner suitable for the printer will be described.
As the toner used in the printer, it is preferable to use a polymerized toner produced by a suspension polymerization method, an emulsion polymerization method, or a dispersion polymerization method, which can easily increase the circularity and reduce the particle size in order to improve the image quality.
In particular, it is preferable to use a polymerized toner having a circularity of 0.97 or more and a volume average particle size of 5.5 [μm] or less. By using a material having an average circularity of 0.97 or more and a volume average particle size of 5.5 [μm], a higher resolution image can be formed.

  The “circularity” here is an average circularity measured by a flow type particle image analyzer FPIA-2000 (trade name, manufactured by Toa Medical Electronics Co., Ltd.). Specifically, in 100 to 150 [ml] of water from which impure solids have been removed in advance in a container, 0.1 to 0.5 [ml] of a surfactant, preferably alkylbenzene sulfonate, is added as a dispersant, Further, about 0.1 to 0.5 [g] of a measurement sample (toner) is added. Thereafter, the suspension in which the toner is dispersed is subjected to a dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes so that the concentration of the dispersion becomes 3000 to 1 [10,000 / μl]. To measure the shape and distribution of the toner. Based on the measurement result, the outer peripheral length of the actual toner projection shape shown in FIG. 2A is C1, and the projection area is S. The outer circumference of the perfect circle shown in FIG. C2 / C1 was determined when the length was C2, and the average value was defined as the circularity.

  The volume average particle diameter can be determined by a Coulter counter method. Specifically, the toner number distribution and volume distribution data measured by the Coulter Multisizer 2e type (manufactured by Coulter) are sent to a personal computer via an interface (manufactured by Nikkaki Co., Ltd.) for analysis. More specifically, a 1% NaCl aqueous solution using first grade sodium chloride is prepared as an electrolytic solution. Then, 0.1 to 5 [ml] of a surfactant, preferably alkylbenzene sulfonate, is added as a dispersant to 100 to 150 [ml] of the electrolytic aqueous solution. Further, 2 to 20 [mg] of toner as a test sample is added thereto, and the dispersion treatment is performed for about 1 to 3 minutes using an ultrasonic disperser. Then, 100 to 200 [ml] of the electrolytic aqueous solution is put into another beaker, and the solution after the dispersion treatment is added to the beaker so as to have a predetermined concentration, and then applied to the Coulter Multisizer 2e type. The aperture is 100 [μm], and the particle size of 50,000 toner particles is measured. As a channel, it is less than 2.00-2.52 [micrometer]; 2.52-less than 3.17 [micrometer]; 3.17-less than 4.00 [micrometer]; 4.00-5.04 [micrometer] Less than 5.04 to 6.35 [μm]; 6.35 to less than 8.00 [μm]; 8.00 to less than 10.08 [μm]; 10.08 to less than 12.70 [μm]; 12.70 to less than 16.00 [μm]; 16.00 to less than 20.20 [μm]; 20.20 to less than 25.40 [μm]; 25.40 to less than 32.00 [μm]; Using 13 channels of 00 to less than 40.30 [μm], toner particles with a particle size of 2.00 [μm] or more and 32.0 [μm] or less are targeted. Then, the volume average particle diameter is calculated based on the relational expression “volume average particle diameter = ΣXfV / ΣfV”. However, X is the representative diameter in each channel, V is the equivalent volume in the representative diameter of each channel, and f is the number of particles in each channel.

  In such a polymerized toner, as described above, if the pulverized toner is removed by the cleaning blade 62 in the same manner as when the pulverized toner is removed from the surface of the photoreceptor 3, the polymerized toner is sufficiently removed from the surface of the photoreceptor 3. Not clean, resulting in poor cleaning. Therefore, when the contact pressure of the cleaning blade 62 to the photosensitive member 3 is increased to improve the cleaning performance, there is a problem that the cleaning blade 62 wears out early. In addition, the frictional force between the cleaning blade 62 and the photosensitive member 3 is increased, and the leading edge portion of the cleaning blade 62 in contact with the photosensitive member 3 is pulled in the moving direction of the photosensitive member 3 so that the leading edge portion is turned. End up. When the tip ridge line portion of the cleaning blade 62 is turned, various problems such as abnormal noise, vibration, and lack of the tip ridge line portion occur.

  Therefore, in the present embodiment, a surface layer having a hardness higher than that of the cleaning blade 62 is provided so as to cover the tip ridge line portion of the cleaning blade 62.

FIG. 3 is a perspective view of the cleaning blade 62, and FIG. 4 is an enlarged configuration diagram of the cleaning blade 62.
The cleaning blade 62 includes a strip-shaped holder 621 made of a rigid material such as metal or hard plastic, and a strip-shaped elastic blade 622. The cleaning blade 62 has a front end ridge line on the entire front end surface 62a and a lower end 62b. A surface layer 623 is formed in the vicinity of the portion 62c so as to cover the tip ridge line portion 62c.
The elastic blade 622 is fixed to one end side of the holder 621 with an adhesive or the like, and the other end side of the holder 621 is supported by the case of the cleaning device 6.

The elastic blade 622 is preferably a highly repulsive elastic body so that it can follow the eccentricity of the photosensitive member 3 and minute undulations on the surface of the photosensitive member, such as urethane rubber, which is a rubber containing a urethane group. It is. In particular, urethane rubber having a hardness at 25 ° C. of 70 to 75 degrees (JIS A) and a rebound resilience of 30 to 68 [%] is preferable. When the hardness of the urethane rubber exceeds 75 degrees, the flexibility becomes poor. For example, when the holder 621 is attached with a slight inclination, the contact pressure between the one end side and the other end side in the axial direction of the cleaning blade 62 is reduced. Different so-called uneven contact is likely to occur, and it is difficult to obtain a uniform contact pressure in the axial direction. As a result, there is a possibility that the cleaning property is deteriorated. On the other hand, when the hardness is less than 70 degrees, the cleaning blade 62 is warped when the contact pressure is set to be high so that even the polymerized toner can be cleaned, and the tip ridge line portion 62c of the cleaning blade 62 is lifted, and the cleaning is performed. A so-called anti-hit phenomenon in which the blade lower surface 62b of the blade 62 abuts against the photosensitive member 3 occurs. When the stomach contact phenomenon occurs, the contact area between the cleaning blade 62 and the surface of the photosensitive member increases rapidly, so that the contact pressure is reduced even if the cleaning blade 62 is pressed with a large force, and the cleaning performance is deteriorated. End up.
Moreover, the fact is that there is almost no urethane rubber having a rebound resilience exceeding 68 [%], and since it is not a general-purpose product, there is a risk that the cost will increase. On the other hand, when the resilience elastic modulus exceeds 68 [%], an abnormal noise such as a high-pitched blade is likely to occur when the cleaning blade 62 is turned over. On the other hand, if the rebound resilience is less than 30 [%], the followability to the eccentricity of the photosensitive member 3 and the minute waviness of the photosensitive member surface is deteriorated, and the cleaning property may be deteriorated.

  Thus, good cleaning properties can be obtained by using urethane rubber having a hardness at 25 ° C. of 70 to 75 degrees (JIS A) and a rebound resilience of 30 to 68 [%] as the urethane rubber.

  The surface layer 623 coats the tip ridge line portion 62c of the cleaning blade 62 by spray coating or dip coating. As the surface layer 623, it is preferable to coat a member having higher hardness than the elastic blade 622. By using a member having a hardness higher than that of the elastic blade 622, the cleaning blade 62 is less likely to be scraped off by the photosensitive member 3 than the elastic blade 622, and compared with a member that makes the elastic blade 622 contact the surface of the photosensitive member. The wear resistance of can be improved. Further, the material of the surface layer 623 is preferably a material having a friction coefficient of 0.1 to 0.6. When the friction coefficient exceeds 0.6, the frictional force between the photoreceptor 3 and the surface layer 623 becomes high, and the cleaning blade 62 is turned over. On the other hand, if the friction coefficient is less than 0.1, the wear resistance of the surface layer 623 is lowered. This is because the amount of the low friction additive for making the friction coefficient less than 0.1 increases.

  The film hardness of the surface layer 623 is preferably a pencil hardness of 7H or more. By setting the pencil hardness to 7H or more, the surface layer 623 is hardly scraped off by the photoreceptor 3, the wear resistance of the cleaning blade 62 can be remarkably improved, and the cleaning performance can be maintained over time. Further, by setting the pencil hardness to 7H or more, the surface layer 623 becomes relatively rigid, and the turning of the tip ridge line portion 62c of the cleaning blade 62 can be further suppressed.

  In addition, it is preferable to form a surface layer on the tip surface 62a and the blade lower surface 62b up to a position 50 [μm] away from the tip ridge line portion 62c that may come into contact with the photosensitive member 3. As a result, the surface of the tip ridge line portion 62c is scraped, the elastic blade 622 and the photoconductor 3 are in direct contact, and the tip ridge line portion 62c is turned up, and a place away from the tip ridge line portion 62c of the tip face 62a by several [μm]. Even if it contacts the photoreceptor 3, the surface layer 623 is also formed there, so that local wear of the front end face 62a is suppressed. Therefore, it is possible to suppress the lack of the leading edge portion 62c of the cleaning blade 62 due to local wear of the leading edge surface 62a. Further, the contact pressure of the cleaning blade 62 becomes higher than necessary due to the mounting error of the photosensitive member 3 or the mounting error of the cleaning blade, and the cleaning blade 62 bends more than necessary, so that the tip ridge line portion 62c of the blade lower surface 62b is bent. Even if a part separated by several [μm] is in contact with the photoreceptor 3, the surface layer 623 is also formed there, so that local wear on the lower surface of the blade can be suppressed.

  The layer thickness of the surface layer 623 is preferably 5 to 20 [μm]. If the layer thickness is 5 [μm] or less, the rigidity of the surface layer becomes weak, and the leading edge portion 62c of the cleaning blade 62 is likely to be turned. On the other hand, when the layer thickness exceeds 20 [μm], toner slip-through increases and cleaning failure tends to occur. This is because the surface layer 623 is formed by adhering a liquid material as in spray coating or dip coating, and therefore the tip ridge line portion 62c is less likely to form a film due to surface tension. For this reason, the layer thickness of the surface layer 623 increases as the distance from the tip ridge line portion 62c increases. When the layer thickness exceeds 20 [μm], the difference between the layer thickness of the tip ridge line portion 62c and the layer thickness at a position away from the tip ridge line portion 62c increases, and the angle of the tip ridge line portion 62c of the cleaning blade 62 becomes an obtuse angle. turn into. When the angle of the tip ridge line portion 62c becomes an obtuse angle, the gap X (see FIG. 4) on the upstream side of the contact portion formed by the blade tip surface 62a and the photosensitive member 1 is compared with the case where the tip ridge line portion 62c is a right angle. Narrow. For this reason, when toner accumulates in the gap by a cleaning operation over a long period of time, the toner in the blocked gap X has no escape, so the toner in the gap X is gradually pushed out to the downstream side of the photoreceptor 3. A cleaning failure occurs.

  As a material of the surface layer 623, a resin is preferable, and an ultraviolet curable resin is more preferable. By using the ultraviolet curable resin, the surface layer 623 having the desired hardness can be obtained simply by irradiating the resin adhered to the tip ridge line portion 62c of the cleaning blade 62 with ultraviolet rays, and the cleaning blade 62 is manufactured at low cost. be able to.

Next, a verification experiment conducted by the applicants will be described.
The durability test was performed by changing the material of the elastic blade 622, the material of the surface layer 623, and the arrangement position of the lubricant application device.

[Elastic blade]
As the elastic blade 622, five urethane rubbers having the following physical properties at 25 [° C.] were prepared.
Urethane rubber 1: 70 degree hardness, 50% rebound resilience (Toyo Tire & Rubber)
Urethane rubber 2: Hardness 72 degrees, rebound resilience 31% (Toyo Tire & Rubber)
Urethane rubber 3: Hardness 71 degrees, rebound resilience 18% (manufactured by Toyo Tire & Rubber)
Urethane rubber 4: Hardness 77 degrees, rebound resilience 27% (manufactured by Syndtech)
Urethane rubber 5: Hardness 70 degrees, rebound resilience 68% (manufactured by Syndtech)

The hardness of urethane rubber was measured according to JIS K6253 using a durometer manufactured by Shimadzu Corporation. The sample was a stack of approximately 2 [mm] sheets so that the thickness was 6 [mm] or more.
The resilience of urethane rubber is No. manufactured by Toyo Seiki Seisakusho. The measurement was performed according to JIS K6255 using a 221 regilynester. The sample was a stack of about 2 [mm] sheets so that the thickness was 4 [mm] or more.

[Surface layer]
The following were used as the surface layer.
(Surface layer 1)
Acrylate monomer: Nippon Kayaku KAYARAD TMPTA 20 parts Polymerization initiator: Ciba Specialty Chemicals Irgacure 184 1 part Low friction coefficient additive: Shin-Etsu Chemical (X-22-174DX) 1 part Solvent: 2-butanone 78 parts coating film Hardness: Pencil hardness 8H
Friction coefficient: 0.1
(Surface layer 2)
Urethane acrylate oligomer: Negami Kogyo UN-3320HA 20 parts Polymerization initiator: Ciba Specialty Chemicals Irgacure 184 1 part Low friction coefficient additive: DIC (Defenza Exp. TF-3026) 0.6 part Solvent: 2-butanone 78 .Part coating film hardness: Pencil hardness 7H
Friction coefficient: 0.3
(Surface layer 3)
Acrylate monomer: Nippon Kayaku KAYARAD DPCA-120 20 parts Polymerization initiator: Ciba Specialty Chemicals Irgacure 184 1 part Solvent: 2-butanone 79 parts Coating film hardness: pencil hardness 5H
Coefficient of friction: 0.8
(Surface layer 4)
Urethane acrylate oligomer: Negami Kogyo UN-904 20 parts Polymerization initiator: Ciba Specialty Chemicals Inc. Irgacure 184 1 part Solvent: 2-butanone 79 parts Coating film hardness: Pencil hardness 9H
Friction coefficient: 0.6
(Surface layer 5)
Urethane acrylate oligomer: Negami Kogyo UN-904 20 parts Polymerization initiator: Ciba Specialty Chemicals Irgacure 184 1 part Low friction coefficient additive: DIC (Exp.TF-3026) 0.6 part Solvent: 2-butanone 78.4 Part coating film hardness: Pencil hardness 9H
Friction coefficient: 0.3
(Surface layer 6)
Acrylate monomer: Nippon Kayaku KAYARAD DPCA-120 20 parts Polymerization initiator: Ciba Specialty Chemicals Co., Ltd. Irgacure 184 1 part Low friction coefficient additive: Shin-Etsu Chemical (X-22-174DX) 1 part Solvent: 2-butanone 78 parts Film hardness: Pencil hardness 5H
Friction coefficient: 0.3

The pencil hardness of the surface layer was measured according to JIS K5600-5-4 using a pencil scratch tester KTVF-2380 manufactured by Cortec Corporation. The sample was obtained by spraying the surface layer material about 10 [μm] on a 50 [mm] × 50 [mm] glass plate.
As the friction coefficient of the surface layer, the maximum static friction coefficient was measured using a tribogear muse 94i manufactured by Shinto Kagaku. The sample was obtained by spraying the coating material on a glass plate of 50 [mm] × 50 [mm] by about 10 [μm].

Next, the configuration of the image forming apparatus for which the verification experiment was performed will be described.
A strip-shaped elastic blade having a thickness of 2 [mm] is prepared using any of the urethane rubbers 1 to 5, and spray coating is performed on the elastic blade to form any one of the surface layers 1 to 6 above. Form. Specifically, each elastic blade made of urethane rubber is applied twice at a spray gun moving speed of 10 [mm / s] from the two directions of the blade surface and the tip surface, and is dry to the touch for 3 minutes. Post-ultraviolet exposure (140 [W / cm] × 3 [m / min] × 5 passes) was performed. However, the lower surface of the blade was regulated so as to form a surface layer with a width of 3 mm at the tip by masking tape.

  The elastic blade on which the surface layer is formed is fixed to a sheet metal holder that can be mounted on the Ricoh color composite machine, image Neo Neo C455, with an adhesive to produce a prototype cleaning blade. Image forming of Examples 1 to 9 and Comparative Examples 1 to 4 in which the prepared prototype cleaning blade was attached to a Ricoh color composite machine image Neo Neo C455 (same configuration as in FIG. 1) and the position of lubricant application was changed. Created a device. The cleaning blade was attached so that the linear pressure was 20 [g / cm] and the cleaning angle was 79 degrees. In addition, a zinc stearate was used as the lubricant, and the pressure test with the lubricant pressure spring was changed from 5000 [mN] to 2000 [mN], and a verification experiment was performed.

  Note that the image forming apparatus of Comparative Example 2 has a configuration as shown in FIG. 5, and has a configuration in which a lubricant coating device is provided upstream of the cleaning blade and the leveling blade is eliminated.

In the verification experiment, a toner prepared by a polymerization method was used. The physical properties of the toner are as follows.
Toner base: circularity 0.98, average particle size 4.9 [μm]
External additive: 1.5 parts of small particle size silica (Clariant H2000)
0.5 parts small particle size titanium oxide (Taika MT-150AI)
1.0 parts of large particle size silica (UFP-30H manufactured by Denki Kagaku Kogyo)

The verification experiment was performed with 300,000 sheets (A4 side) of continuous evaluation of an evaluation environment: 20 [° C.] and 65 [% RH], and a sheet passing condition: an image area ratio of 5 [%]. And the following items were evaluated.
[Evaluation item]
Occurrence of cleaning failure: Existence (image area ratio 5% chart output visual observation)
Blade edge wear width: Wear width seen from the bottom side of the blade Photoconductor wear amount: Large wear amount

  The photoconductor wear amount was obtained by measuring the photoconductor film thickness before and after the verification experiment using an eddy current film thickness meter Fischer scope MMS (manufactured by Fischer) and calculating the difference.

  The material of the urethane rubber used in Examples 1-9 and Comparative Examples 1-4, the material of the surface layer, the lubricant application method, and the results of the verification experiment are shown below. In addition, the layer thickness of the surface layer was measured with a cross section of an elastic blade separately coated in the same manner using a Keyence microscope VHX-100. The sample was a cross-section cut using a trimming razor for SEM sample preparation manufactured by Nisshin EM.

Table 1 above summarizes the results of verification experiments of Examples 1 to 9 and Comparative Examples 1 to 4.
As shown in Table 1, in Examples 1 to 9, no defective cleaning occurred and good images could be obtained over time.

  On the other hand, in Comparative Example 1, chatter vibration occurred. This is because the friction coefficient of the surface layer is as large as 0.8, so that the frictional force with the photoreceptor is large. For this reason, it is considered that the surface layer was worn over time and the strength over time decreased, eventually the frictional force was won and the cleaning blade was turned over, resulting in chatter vibration.

  In Comparative Example 2, four strip-like cleaning defects occurred. Further, when the surface of the photoreceptor after the verification experiment was observed, filming was confirmed. In addition, the amount of wear on the surface of the photoconductor also increased compared to Examples 1-9. This is because the position of lubricant application is upstream of the cleaning blade in the direction of movement of the photosensitive member, and the application brush becomes dirty and it becomes impossible to uniformly apply the lubricant to the surface of the photosensitive member over time. It is thought that. Further, when the image was confirmed, various abnormal images such as transfer unevenness, character missing, bug eater, image blur, and blurring were confirmed in the initial use. This is because the lubricant application position is upstream of the cleaning blade in the moving direction of the photosensitive member, so that the lubricant applied by the cleaning blade is removed together with the transfer residual toner, and the amount of lubricant applied to the surface of the photosensitive member is reduced. This is thought to be due to a bias.

  In Comparative Example 3, five strip-like cleaning defects occurred. Since no lubricant is applied to the surface of the photoconductor, the cleaning blade surface was worn early due to friction with the surface of the photoconductor, and it is considered that a cleaning failure occurred. Further, when the surface of the photoreceptor after the verification experiment was observed, filming was confirmed. Since no lubricant is applied to the surface of the photoconductor, the adhesion between the photoconductor and the toner becomes strong, and it is considered that filming has occurred. Further, the amount of wear on the surface of the photoreceptor was also worn by 2.0 [μm]. This is probably because the lubricant was not applied to the surface of the photoconductor, so that the coefficient of friction on the surface of the photoconductor was high, and the surface hardness was scraped off by the hard surface layer having a pencil hardness of 8H.

  In Comparative Example 4, streaky cleaning failure occurred. Further, when the front end surface of the cleaning blade after the poor cleaning was observed, the chipping occurred. Since the surface layer is not formed, the frictional force with the photosensitive member is large, and the strength of the tip ridge line portion is not sufficient, so that the tip ridge line portion of the cleaning blade is turned up and a part of the tip surface is formed. It is considered that the tip face was chipped due to local wear.

  On the other hand, in Examples 1 to 9, since the friction coefficient is as low as 0.1 to 0.6, the frictional force with the photoconductor is kept low, the occurrence of turning of the tip ridge line portion of the cleaning blade is suppressed, and chattering is achieved. There was no vibration, abnormal noise, or tipping, and good cleaning was maintained for a long time. Further, since the lubricant is applied downstream of the cleaning blade in the moving direction of the photoreceptor surface, the residual toner is removed and the lubricant can be applied to the surface of the photoreceptor 3 in a clean state. Therefore, a certain amount of lubricant can be applied to the photoreceptor surface over time without the application brush becoming dirty over time. For this reason, since a uniform lubricant can be applied to the surface of the photoconductor with a leveling blade over time, cleaning failure, filming of the photoconductor surface, and abrasion of the photoconductor surface can be suppressed over time.

  Furthermore, in Example 5 in which the pencil hardness of the surface layer was 5H, the blade wear width was wider than in other examples having a pencil hardness of 7H or more. This is because the durability of the surface layer is improved in Examples 1 to 4 and Examples 6 to 9 in which the pencil hardness is 7H or higher compared to Example 5 in which the pencil hardness of the surface layer is 5H. It is thought that wear was suppressed.

  Further, when the surface layer of the cleaning blade after the verification experiment was observed for Examples 1 to 9, fine cracks were generated, but no events that could cause abnormal images such as defective cleaning were confirmed. The reason for this is not clear, but it is considered that the image forming apparatuses of Examples 1 to 9 are provided with a lubricant application device, and the lubricant is applied to the surface of the photoreceptor by the lubricant application device.

  The present embodiment is an example of a so-called monochrome image forming apparatus, but may be a color image forming apparatus. Hereinafter, a specific example in which the feature points of the present embodiment are applied to a color image forming apparatus will be described.

FIG. 7 is a diagram showing an example in which the present invention is applied to a printer which is a so-called tandem type full-color image forming apparatus.
In FIG. 7, reference numeral (3C, 3M, 3Y, 3K) denotes a drum-shaped photoconductor, and the photoconductors 3C, 3M, 3Y, 3K rotate in the direction of the arrow in the figure and are charged around at least in the order of rotation. Devices 4C, 4M, 4Y, 4K, developing devices 5C, 5M, 5Y, 5K, and cleaning devices 6C, 6M, 6Y, 6K are arranged.

  Laser light LC, LM, LY, LK from an exposure device (not shown) is irradiated from the back side of the photoreceptor between the charging devices 4C, 4M, 4Y, 4K and the developing devices 5C, 5M, 5Y, 5K. Electrostatic latent images are formed on 3C, 3M, 3Y, and 3K. Then, four process cartridges 1C, 1M, 1Y, and 1K centering on such photoreceptors 3C, 3M, 3Y, and 3K are juxtaposed along a transfer conveyance belt 14 that is a transfer material conveyance unit. The transfer / conveying belt 14 contacts the photosensitive members 3C, 3M, 3Y, and 3K between the developing devices 5C, 5M, 5Y, and 5K of the process cartridges 1C, 1M, 1Y, and 1K and the cleaning devices 6C, 6M, 6Y, and 6K. In addition, transfer brushes 7C, 7M, 7Y, and 7K for applying a transfer bias are arranged on the surface (back surface) of the transfer and transport belt 14 that contacts the back side of the photoconductor. Each of the process cartridges 1C, 1M, 1Y, and 1K has a different toner color inside the developing device, and the others have the same configuration.

  In the color electrophotographic image forming apparatus having the configuration shown in FIG. 7, the image forming operation is performed as follows. First, in each of the process cartridges 1C, 1M, 1Y, and 1K, the photoconductors 3C, 3M, 3Y, and 3K are charged by the charging devices 4C, 4M, 4Y, and 4K that rotate in the direction of the arrow (the direction around the photoconductor). Next, an electrostatic latent image corresponding to each color image to be created is formed by laser light LC, LM, LY, and LK by an exposure device (not shown) arranged inside the photoconductor.

Next, the latent image is developed by the developing devices 5C, 5M, 5Y, and 5K to form a toner image. The developing devices 5C, 5M, 5Y, and 5K are developing devices that perform development with toners of C (cyan), M (magenta), Y (yellow), and K (black), respectively, and the four photosensitive members 3C, 3M, and 3Y. , 3K toner images of each color are superimposed on the transfer paper.
The transfer paper P is sent out from the tray by the paper supply roller 15, temporarily stopped by the upper registration roller 12 and the lower registration roller 13, and sent to the transfer conveyance belt 14 in synchronization with the image formation on the photosensitive member. The transfer paper P held on the transfer conveyance belt 14 is conveyed, and the toner images of the respective colors are transferred at the contact positions (transfer portions) with the photoconductors 3C, 3M, 3Y, 3K.
The toner image on the photoconductor is transferred onto the transfer paper P by an electric field formed by a potential difference between the transfer bias applied to the transfer brushes 7C, 7M, 7Y, and 7K and the photoconductors 3C, 3M, 3Y, and 3K. The Then, the recording paper P on which the four color toner images are passed through the four transfer portions is conveyed to the fixing device 16 where the toner is fixed and discharged to a paper discharge portion (not shown). Further, the residual toner that is not transferred by the transfer unit and remains on the photosensitive members 3C, 3M, 3Y, and 3K is collected by the cleaning devices 6C, 6M, 6Y, and 6K. In the example of FIG. 7, the image forming elements are arranged in the order of C (cyan), M (magenta), Y (yellow), and K (black) from the upstream side to the downstream side in the transfer paper conveyance direction. However, it is not limited to this order, and the color order is arbitrarily set.
In FIG. 7, the charging device is in contact with the photoconductor. By providing an appropriate gap (about 10 to 200 μm) between the two, the wear amount of the both can be reduced, and the toner film on the charging member can be reduced. It can be used satisfactorily with less ming.

Also in this color electrophotographic image forming apparatus, the cleaning devices 6C, 6M, 6Y, and 6K of the process cartridges 1C, 1M, 1Y, and 1K include a cleaning blade, and the tip edge line portion of the cleaning blade has a friction coefficient. Covered with a surface layer of 0.1 to 0.6. Further, each of the process cartridges 1C, 1M, 1Y, and 1K is located downstream of the contact position of the cleaning blade in contact with the photosensitive member, in the photosensitive member surface movement direction, and upstream of the developing region of the developing device in the photosensitive member surface movement direction. A lubricant application device for applying a lubricant to the surface of the photoreceptor is provided on the side.
Since this color electrophotographic image forming apparatus has the above-described configuration, even if the linear pressure of the cleaning blade is increased so that the polymerized toner can be cleaned, the leading edge portion of the cleaning blade does not turn up. Good cleaning properties can be maintained over time. Further, the progress of abrasion of the photoreceptor is suppressed, and a good image can be maintained over a long period.

  As described above, in the image forming apparatus of the present embodiment, the photosensitive member as the image carrier, the charging charger as the charging unit for charging the surface of the photosensitive member, and the latent image forming unit for forming an electrostatic latent image on the charged surface of the photosensitive member. A developing device that is a developing unit that develops an electrostatic latent image formed on the surface of the photoconductor to form a toner image, and a transfer that is a transfer unit that transfers the toner image on the surface of the photoconductor to a transfer sheet as a transfer body. And a cleaning device that is a cleaning unit having a cleaning blade that contacts the photosensitive member and cleans the transfer residual toner that adheres to the surface of the photosensitive member. The cleaning blade is a strip-shaped elastic blade that covers the tip ridge line portion of the elastic blade, is harder than the elastic blade, and has a surface layer with a friction coefficient of 0.1 to 0.6. . By covering the tip ridge line portion of the cleaning blade with a surface layer harder than the elastic blade, the wear resistance of the cleaning blade is improved and the life of the cleaning blade can be extended. Further, by setting the friction coefficient of the surface layer to 0.1 or more and 0.6 or less, it is possible to reduce the frictional force between the photoconductor and the cleaning blade, and to suppress the deterioration of the wear resistance of the surface layer. Can do. Furthermore, since the surface layer is harder and more difficult to deform than the elastic blade, deformation of the tip ridge line portion of the cleaning blade is suppressed, and turning of the tip ridge line portion can be suppressed. Therefore, chatter vibration and abnormal noise can be suppressed, and local wear on the cleaning blade tip surface can be suppressed.

In the image forming apparatus according to the present embodiment, the surface of the photoconductor surface is moved downstream of the contact position where the lubricant coating device contacts the photoconductor of the cleaning blade, and the surface of the photoconductor is moved more than the developing area of the developing device. Arranged upstream in the direction. Thus, the lubricant applied by the lubricant application device is not removed together with the transfer residual toner by the cleaning blade before passing through the development region. Therefore, the amount of lubricant on the surface of the photoreceptor passing through the development area can be made uniform, and the adhesion force between the toner adhered to the surface of the photoreceptor by the developing device and the photoreceptor can be made uniform. As a result, good transferability can be obtained and a good image can be obtained.
Further, almost no toner adheres to the surface of the photosensitive member from the contact position where the cleaning blade contacts the photosensitive member to the development area. Therefore, by applying the lubricant in this region, it is possible to suppress the toner from adhering to the application brush, and the lubricant can be applied uniformly in the axial direction over time. Thereby, a good cleaning property and a good image can be maintained over time.

  Further, by setting the pencil hardness of the surface layer to 7 [H] or more, the wear resistance can be improved and the life of the cleaning blade can be extended.

  In addition, by using rubber containing a urethane group as the elastic blade, the cleaning blade can be flexibly deformed to maintain a predetermined contact pressure even if the photoreceptor is eccentric, etc. Cleanability can be maintained.

  Further, the lubricant application device includes an application brush as a lubricant supply means for supplying a lubricant to the surface of the photoconductor, and a leveling blade as a lubricant leveling means for leveling the lubricant supplied to the surface of the photoconductor by the application brush. And. As a result, the lubricant can be uniformly applied to the surface of the photoreceptor.

  By using a blade member as the lubricant leveling means, it is possible to level the lubricant supplied to the surface of the photoreceptor with an inexpensive configuration.

  In addition, since the photosensitive member and at least the cleaning device are integrally supported and the process cartridge is detachable from the apparatus main body, the photosensitive member and the cleaning device can be easily exchanged.

  Further, the photoconductive member comprises an organic photoconductor using a cross-linkable charge transport material and an elastic blade, covers the tip ridge line portion of the elastic blade, is harder than the elastic blade, and has a friction coefficient of 0.1-0. Since the cleaning blade having the surface layer 6 is provided, a process cartridge having a long life and good cleaning properties can be provided.

  Also, the lubricant is a solid lubricant, and is configured to scrape and supply the solid lubricant to the photoconductor while rotating with an application brush which is a roller brush. A lubricant can be supplied to the surface.

  Further, since the lubricant is a metal soap and is at least one metal soap selected from zinc stearate, aluminum stearate and calcium stearate, the coefficient of friction on the surface of the photoreceptor can be lowered, and the photosensitive material can be reduced. The body wear can be suppressed well.

  In addition, the photosensitive member, at least the cleaning device and the lubricant application device are integrally supported, and the process cartridge is detachable from the main body of the device, so that the photosensitive member, the cleaning device and the lubricant application device can be easily replaced. It can be carried out.

  Also, a cleaning blade comprising a photoconductor and an elastic blade, covering a tip ridge line portion of the elastic blade, having a surface layer harder than the elastic blade and having a friction coefficient of 0.1 to 0.6, and a cleaning blade Further, since the lubricant application device is provided on the downstream side in the moving direction of the photosensitive member, it is possible to provide a process cartridge having a long life and good cleaning properties.

1 is a schematic configuration diagram of a printer according to an embodiment of the present invention. (A) And (b) is explanatory drawing for demonstrating the measuring method of circularity. The perspective view of a cleaning blade. The enlarged block diagram of a cleaning blade. FIG. 3 is a schematic configuration diagram of an image forming apparatus of Comparative Example 2. 1 is a main part configuration diagram of a tandem full-color image forming apparatus. (A) is a figure which shows the state in which the cleaning blade front-end ridgeline part was turned up. (B) is a figure explaining the local abrasion of the front end surface of a cleaning blade. (C) is a figure which shows the state which the front-end ridgeline part of the cleaning blade missing.

Explanation of symbols

1: Process cartridge 3: Photoconductor 5: Developing device 6: Cleaning device 10: Lubricant coating device 62: Cleaning blade 622: Elastic blade 623: Surface layer

Claims (9)

An image carrier;
Charging means for charging the surface of the image carrier;
Latent image forming means for forming an electrostatic latent image on the surface of the charged image carrier;
Developing means for developing the electrostatic latent image formed on the surface of the image carrier to form a toner image;
Transfer means for transferring the toner image on the surface of the image carrier to a transfer body;
In an image forming apparatus comprising a cleaning unit having a cleaning blade that contacts the surface of the image carrier and cleans transfer residual toner attached to the surface of the image carrier.
The cleaning blade is a strip-shaped elastic blade, and
Covering the tip ridge line portion of the elastic blade, having a surface layer that is harder than the elastic blade and has a friction coefficient of 0.1 or more and 0.6 or less,
The image carrier on the downstream side of the image carrier surface movement direction with respect to the contact position of the cleaning blade with the image carrier and on the upstream side of the image carrier surface movement direction with respect to the developing region of the developing means. An image forming apparatus comprising a lubricant applying means for applying a lubricant to a surface. The image forming apparatus according to claim 1.
An image forming apparatus, wherein the surface layer has a pencil hardness of 7 [H] or more. The image forming apparatus according to claim 1 or 2,
An image forming apparatus using a rubber containing a urethane group as the elastic blade. The image forming apparatus according to any one of claims 1 to 3,
The lubricant application means includes a lubricant supply means for supplying a lubricant to the surface of the image carrier, and a lubricant leveling means for leveling the lubricant supplied to the surface of the image carrier by the lubricant supply means. An image forming apparatus comprising: The image forming apparatus according to claim 4.
An image forming apparatus using a blade member as the lubricant leveling means. The image forming apparatus according to claim 4 or 5,
The lubricant is a solid lubricant,
2. An image forming apparatus according to claim 1, wherein a roller-like brush that scrapes off the solid lubricant while rotating and supplies the lubricant to the image carrier is used as the lubricant supply means. The image forming apparatus according to claim 1.
The image forming apparatus, wherein the lubricant is a metal soap, and is at least one metal soap selected from zinc stearate, aluminum stearate, and calcium stearate. The image forming apparatus according to claim 1,
An image forming apparatus comprising: a process cartridge that integrally supports the image carrier, at least the cleaning unit, and the lubricant application unit, and is detachable from the apparatus main body. In a process cartridge that integrally supports an image carrier and at least a cleaning unit having a cleaning blade that cleans transfer residual toner attached to the surface of the image carrier, and is detachable from the image forming apparatus main body,
The cleaning blade is a strip-shaped elastic blade, and
It covers the tip ridge line portion of the elastic blade, is harder than the elastic blade, and has a surface layer with a friction coefficient of 0.1 or more and 0.6 or less,
The image carrier on the downstream side of the image carrier surface movement direction with respect to the contact position of the cleaning blade with the image carrier and on the upstream side of the image carrier surface movement direction with respect to the developing region of the developing means. A process cartridge comprising a lubricant application means for applying a lubricant to a surface.

Images