JP2006017916A - Image forming apparatus and process cartridge with cleaning blade - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus and a process cartridge in which slipping of much toner through a contact part of a cleaning blade with a surface of an image carrier member at a time is suppressed and good cleaning can be carried out even when spherical toner is used. <P>SOLUTION: The cleaning blade 20 has a thick portion 20γ in a nearly central part and a blade tip side thin portion 20α and a blade root side thin portion 20β at both ends so that the shape of a cross section of the cleaning blade 20 is made nearly convex. A metal support plate 3 is bonded in such a manner that it sticks fast to a blade side face of the blade root side thin portion 20β, and a shape is provided in which a step face 20δ of the thick portion 20γ sticks fast to a tip face of the metal support plate 3. Repulsive elasticity modulus of the cleaning blade 2 at 23°C is set within a range of 8.0-30[%], a JIS A hardness of the blade is set within a range of 70-90[°], and linear pressure at a contact part of the blade with a photoreceptor drum 1 is set within a range of 0.784-1.176 [N/cm]. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine, a printer, and a facsimile machine that uses a cleaning blade to remove spherical toner adhered on an image carrier such as a photoconductor, and a process cartridge used therefor.

  As this type of image forming apparatus, there is widely known an apparatus that cleans residual toner remaining on the surface of the image carrier after the transfer process by scraping with a cleaning blade. As this cleaning blade, a metal blade or a blade formed of an elastic material such as urethane rubber is known. The former cleaning blade is difficult to deform at the contact portion with the surface of the image carrier, so that the processing accuracy of the blade tip that contacts the surface of the image carrier is low or there are minute irregularities on the surface of the image carrier. Cannot make contact between the blade tip and the surface of the image carrier. for that reason. A minute gap is formed at the contact portion between the blade tip and the surface of the image carrier. If there is such a minute gap, the toner slips through the gap and a cleaning failure is likely to occur. On the other hand, the latter cleaning blade deforms along the surface of the image carrier because the contact portion with the surface of the image carrier is deformed. Even if there is unevenness, it can be in close contact with the surface of the image carrier. Therefore, compared to the former cleaning blade, it can be said that the toner is less likely to slip through and has excellent cleaning performance. Therefore, a cleaning blade made of an elastic material such as rubber has been widely put into practical use.

In recent years, the demand for image quality of electrophotographic image forming apparatuses has been increasing. In order to improve the image quality, reduction of the particle size and spheroidization of the toner are effective means, and toner close to a sphere formed by a polymerization method or the like (hereinafter referred to as “spherical toner”) is used. Are becoming mainstream. This spherical toner has characteristics such as higher transfer efficiency than conventional pulverized toner (unshaped toner), and is known to be able to meet the recent demand for higher image quality. However, the spherical toner is difficult to remove from the surface of the image carrier using a conventional cleaning blade for cleaning the pulverized toner, and there is a problem that poor cleaning occurs. is doing.
Here, the conventional cleaning with the cleaning blade will be described. The cleaning blade abuts in the counter direction with respect to the rotation direction of the image carrier. When the transfer residual toner remaining on the image carrier after the transfer process reaches the edge of the cleaning blade, this is transferred to the image carrier. Scrape off.
Since an elastic body such as urethane rubber is used for the cleaning blade, the elastic body and the image carrier alone have a very high coefficient of friction, and as such, the cleaning blade cannot slide against the image carrier, and the blade Entrainment and chattering will occur. However, a developer used in an electrophotographic apparatus and a fine powder having a small particle diameter added for charge control and fluidity control of the developer are interposed between the blade and the image carrier, so that the image carrier Becomes slidable with respect to the cleaning blade. Further, a part of the transfer residual toner scraped off from the image carrier by the cleaning blade stays at the blade edge by the rotation of the image carrier. When the transfer residual toner stays at the blade edge, the frictional force acting between the cleaning blade and the image carrier is reduced, so that a stable cleaning property without the scratch of the cleaning blade can be obtained.
On the other hand, when the spherical toner is used, the spherical toner cannot stay on the blade edge, and the frictional force acting between the cleaning blade and the image carrier cannot be reduced. If the frictional force is not reduced, the surface of the image carrier is scraped to generate powder, and the shaved powder aggregates at the contact portion between the cleaning blade and the image carrier, which makes the contact portion unstable. The toner slips through.

  In Patent Document 1, spherical toner having a high roundness with a shape factor SF-1 of 100 to 140 and a shape factor SF-2 of 100 to 120 is used, and this is countered with respect to the image carrier surface movement direction. An image forming apparatus that performs cleaning with a cleaning blade that is in contact with a direction is disclosed. In this image forming apparatus, numerical ranges of various parameters are defined in order to suppress toner slipping that occurs at the contact portion between the cleaning blade and the image carrier surface when spherical toner is used. Specifically, the linear pressure at the contact portion between the cleaning blade and the surface of the image carrier is set to 20 [gf / cm] to 60 [gf / cm] (0.196 [N / cm] to 0.588 [N]. / Cm]). The cleaning blade has a hardness of 50 to 80 [°] and a rebound resilience of 10 to 50 [%].

Japanese Patent Laid-Open No. 2001-312191

  However, as a result of intensive studies by the present inventors, as described in Patent Document 1, when the linear pressure is less than 60 [gf / cm] (0.588 N / cm), the above-mentioned spherical toner slips sufficiently. It was found that it was not possible to prevent the occurrence of poor cleaning. Therefore, the present inventors conducted various experiments to uniquely elucidate the mechanism of occurrence of poor cleaning due to slipping of spherical toner. It was concluded that the mechanism of occurrence of this poor cleaning is as follows. Hereinafter, the mechanism will be described.

  FIG. 12 is a view for explaining the arrangement of the cleaning blade 2 as an elastic blade with respect to the photosensitive drum 1 as an image carrier. The cleaning blade 2 is in contact with the surface of the photosensitive drum 1 such that the tip of the cleaning blade 2 is in the counter direction with respect to the surface movement direction A of the photosensitive drum 1. The initial contact angle at this time is θ, and the amount of biting is d. Here, the “initial contact angle” is defined as follows. That is, when viewed from the axial direction of the photosensitive drum 1, when the photosensitive drum 1 is not present, the downstream side surface (hereinafter referred to as the photosensitive drum 1 surface movement direction A) of the cleaning blade 2 tip portion (two-dot chain line in the figure). This is simply referred to as the “downstream side surface”.) The tangent line G of the surface portion of the photosensitive drum 1 at the intersection C between the virtual line F where the 2a is located and the surface of the photosensitive drum 1 is taken. An angle θ formed by the tangent line G and the virtual line F is defined as an initial contact angle. In addition, “the amount of biting” is defined as follows. That is, when viewed from the axial direction of the photosensitive drum 1, the tangent line G and the photosensitive drum surface moving direction A downstream of the cleaning blade 2 tip surface, which is the leading edge of the elastic blade, when the photosensitive drum 1 is absent. The distance d from the imaginary line H parallel to the tangent line G passing through the imaginary point where the side edge (hereinafter simply referred to as “blade edge”) 2b is located is defined as the amount of biting. In order to realize such an arrangement of the cleaning blade 2, for example, first, the blade edge 2 b is brought into contact with the surface of the photosensitive drum 1. In this state, the cleaning blade 2 is moved along the normal direction of the surface portion of the photosensitive drum 1 at the contact point so that the relative posture of the cleaning blade 2 with respect to the surface of the photosensitive drum 1 is not changed. 1 Move to the surface side to the state shown in FIG.

The cleaning blade 2 is bonded to a metal support plate 3 as a support member fixed to a casing (not shown) at the end (rear end) opposite to the front end that contacts the surface of the photosensitive drum 1. Such a cleaning blade 2 has a thickness t ₁ of 0.5 [mm] or more and 2.0 [mm] or less, and a length t (free end portion) that is not bonded to the metal support plate 3. ₂ is generally 3.0 [mm] or more and 10.0 [mm] or less. As the material of the cleaning blade 2, an elastic member such as rubber is used. The polyurethane has a hardness of 65 [°] to 80 [°] and a rebound resilience of 20 [%] to 60 [%]. Is widely used.

FIG. 13 is a cross-sectional view of the deformation state of the blade tip portion when the blade tip portion of the cleaning blade 2 is brought into contact with the biting amount d while the photosensitive drum 1 is stationary as viewed from the axial direction of the photosensitive drum 1. FIG. The blade tip at this time is in a state where the downstream side surface thereof is in contact with the surface of the photosensitive drum 1 as shown in the figure. This state is called “slip state”.
FIG. 14 is a cross-sectional view of the deformed state of the blade tip when the surface of the photosensitive drum 1 is moved in the direction of arrow A in the state shown in FIG. 13 as seen from the axial direction of the photosensitive drum. When the surface of the photosensitive drum 1 moves in the direction of the arrow A in the figure, the downstream side surface portion (including the blade edge 2b) of the blade tip that was in contact with the surface of the photosensitive drum is subjected to frictional force with the surface of the photosensitive drum. Is pulled in the direction of arrow A in the figure. As a result, the blade edge 2b moves, and finally, as shown in FIG. 14, a part of the blade front end surface including the blade edge 2b comes into contact with the surface of the photosensitive drum to form a blade nip. . This state is called “stick state”. The elastic deformation around the blade edge 2b in the stick state is maintained when the restoring force due to the elastic deformation and the dynamic frictional force of the contact portion are in an equilibrium state while the surface of the photosensitive drum 1 is moving. While the surface movement of 1 is stopped, it is maintained by the static frictional force of the contact portion that is larger than the restoring force due to the elastic deformation. Accordingly, the dynamic frictional force of the contact portion does not change during the surface movement of the photosensitive drum 1, and the static frictional force of the contact portion is based on the restoring force against the elastic deformation around the blade edge 2b of the blade tip surface in the stick state. If it is larger, the stick state is kept constant.

  In the stick state, the area of the portion where the cleaning blade 2 and the surface of the photosensitive drum 1 are in contact with each other is smaller than that in the slip state. In addition, in the stick state, the periphery of the blade edge 2b, which does not occur in the slip state, is compressed and deformed in the normal direction of the blade tip surface due to the frictional force received from the surface of the photosensitive drum 1. The restoring force against the compression deformation acts to increase the contact pressure between the cleaning blade 2 and the surface of the photosensitive drum 1. As described above, in the stick state, the contact area with the surface of the photosensitive drum 1 is small, and the rebound resilience due to compression acts to increase the contact pressure between the cleaning blade 2 and the surface of the photosensitive drum 1. Therefore, the contact pressure is higher than that in the slip state, and the toner does not easily slip through. Therefore, in order to suppress toner slipping, it is important to stably maintain the stick state during cleaning.

The inventors have found through experiments that the cleaning blade 2 in contact with the photosensitive drum 1 is partially reciprocating between a stick state and a slip state (hereinafter referred to as stick-slip motion). . In this experiment, first, the cleaning blade 2 is brought into contact with the surface of a transparent surface moving member having the same friction characteristics as the surface of the photosensitive drum 1. Then, the surface moving member is moved in a state where spherical toner is adhered to the surface, and a contact portion between the cleaning blade 2 and the surface moving member at that time is photographed with a camera from the back surface of the surface moving member, The state of stick-slip motion of the cleaning blade 2 was observed. This occurs when the coefficient of friction of the surface of the photosensitive drum 1 partially changes when the state is stable in a stick state, and the frictional force between the surface of the photosensitive drum 1 and the cleaning blade 2 changes. Specifically, when the friction coefficient is partially reduced, the restoring force against the elastic deformation of the cleaning blade 2 becomes larger than the frictional force acting between the photosensitive drum 1 and the cleaning blade 1, and a slip state occurs. In the slip state, the restoring force is smaller than the frictional force, so that the surface is returned to the stick state as the photosensitive drum 1 moves. On the other hand, when the friction coefficient partially increases, the frictional force acting between the photosensitive drum 1 and the cleaning blade 2 becomes larger than the restoring force against the elastic deformation of the cleaning blade 2, and the downstream side surface portion of the blade tip portion Further, it is pulled in the direction of arrow A in the figure. When a portion having a large friction coefficient passes, the restoring force with respect to the elastic deformation of the cleaning blade 2 becomes larger than the frictional force acting between the photosensitive drum 1 and the cleaning blade 2, and a slip state occurs. In the slip state, the restoring force becomes smaller than the frictional force, so that the surface of the photosensitive drum 1 is moved back to the stick state.
In the stick-slip motion of the cleaning blade 2, it was observed that many spherical toners slipped between the cleaning blade 2 and the photosensitive drum 1 when the cleaning blade 2 was slipping.
On the other hand, when the pulverized toner that can be easily cleaned by the cleaning blade 2 is cleaned, the toner stays at the contact portion between the blade edge 2 b and the photosensitive drum 1, and is between the cleaning blade 2 and the photosensitive drum 1. The working friction force decreases. By reducing the frictional force, a stable blade nip with little stick-slip phenomenon was formed, and good cleaning properties could be obtained.
When spherical toner is used, the spherical toner cannot stay on the blade edge, so that the cleaning blade 2 repeats stick-slip due to frictional force with the photosensitive drum 1. As a result, an unstable blade nip is formed, and spherical toner slips through, resulting in poor cleaning.

Up to this point, the toner slipped out due to the stick-slip motion and the cleaning failure has been described. However, the problem with the conventional cleaning blade 2 shown in FIG. 12 is not limited thereto. Stress concentrates on the cleaning blade 2 in the vicinity of the support plate edge 3b, which is the leading edge of the metal support plate 3 in contact with the cleaning blade 2, and buckling occurs at a portion (hereinafter referred to as stress concentration portion) 2S where the stress is concentrated. There was a fear.
In order to obtain a linear pressure necessary to prevent the spherical toner from slipping through the contact portion between the cleaning blade 2 and the photosensitive drum 3, the cleaning blade 2 is outside the photosensitive drum 1 by the amount of bite d. Bending stress is generated. And this bending stress becomes the maximum in the stress concentration part 2S. Further, the stress applied to the cleaning blade 2 is not limited to the bending stress described above, and it is conceivable that a compressive stress acts in a direction parallel to the virtual line F in the drawing. When the stress applied to the stress concentration portion 2S reaches the limit due to these stresses, the cleaning blade 2 is buckled. When buckling occurs, a desired linear pressure cannot be obtained at the contact portion between the cleaning blade 2 and the photosensitive drum 1. If the desired linear pressure cannot be obtained, a large amount of toner slips at a time, resulting in poor cleaning.

  The present invention has been made in view of the above background. The object of the present invention is to provide a large number of contact portions between the elastic blade and the surface of the image carrier at one time even when spherical toner is used. An object of the present invention is to provide an image forming apparatus and a process cartridge in which toner can be prevented from slipping through and good cleaning can be performed.

In order to achieve the above object, the invention of claim 1 is such that a predetermined range including an image carrier that carries a toner image on its surface and moves on the surface, and a predetermined range including a tip edge line of the image carrier is in contact with the surface of the image carrier. An image forming apparatus comprising: a cleaning device that removes unnecessary toner attached to the surface of the image carrier from the surface of the image carrier using an elastic blade supported by a support member; The elastic blade is arranged so as to abut against the counter blade in the counter direction, and the stress applied to the elastic blade portion in the vicinity of the tip ridge line of the support member in contact with the elastic blade is dispersed to displace the elastic blade portion. Reinforcing means is provided, and the elastic body forming the elastic blade has a rebound resilience at 23 ° C. of 8.0 [%] or more and 30 [%] or less, and a JISA hardness of 70 [°] or more and 90 [°] or less. The pressing force per unit length in the axial direction (hereinafter referred to as linear pressure) applied to a predetermined range in contact with the surface of the image carrier is 0.784 [N / cm] or more and 1.176 [N]. / Cm] or less (80 [gf / cm] or more and 120 [gf / cm] or less).
According to a second aspect of the present invention, there is provided the image forming apparatus according to the first aspect, wherein at least a part of the thickness of the elastic blade is increased from the rear end to the front end of the elastic blade, and the thickness of the thickened portion is increased. However, the elastic blade is attached to the support member so as to be in close contact with the front end surface of the support member, and the reinforcing means is constituted by the thickened portion.
According to a third aspect of the present invention, in the image forming apparatus of the first aspect, the reinforcing means is used as the reinforcing means so that a rear end surface thereof is in close contact with a side surface of the elastic blade on the support member side. The reinforcing member is fixedly provided.
According to a fourth aspect of the present invention, in the image forming apparatus according to the first to third aspects, the elastic body forming the elastic blade is a polyurethane elastomer.
According to a fifth aspect of the present invention, in the image forming apparatus according to the first to fourth aspects, a lubricant is added to the toner that forms the toner image.
According to a sixth aspect of the present invention, in the image forming apparatus according to any of the first to fourth aspects, a lubricant applying means for applying a lubricant to the surface of the image carrier is provided.
According to a seventh aspect of the present invention, in the image forming apparatus according to the first to fourth aspects, a lubricating substance is internally added to the outermost layer of the image carrier.
According to an eighth aspect of the present invention, in the image forming apparatus according to the first to seventh aspects, the image carrier has a protective layer containing inorganic differential particles.
According to a ninth aspect of the present invention, in the image forming apparatus according to the first to seventh aspects, the image carrier is provided with a protective layer, and the binder resin of the protective layer has a crosslinked structure. .
According to a tenth aspect of the present invention, in the image forming apparatus according to the ninth aspect, the structure of the binder resin having the crosslinked structure of the protective layer has a charge transporting site.
According to an eleventh aspect of the present invention, in the image forming apparatus according to any of the first to tenth aspects, the image carrier and the cleaning device are integrally supported, and the process cartridge is detachable from the main body of the image forming apparatus. It is characterized by.
According to a twelfth aspect of the present invention, in the image forming apparatus of the eleventh aspect, the process cartridge has a heat insulating structure.

In the image forming apparatus according to the first to twelfth aspects, the numerical ranges of various parameters of the elastic blade that contacts the image carrier and cleans the transfer residual toner on the image carrier are as follows.
An axial unit that acts on a predetermined range in contact with the surface of the image carrier, with a resilience at 23 ° C. of 8.0 [%] to 30 [%] and a JISA hardness of 70 [%] to 90 [°]. The pressing force per length is 0.784 [N / cm] or more and 1.176 [N / cm] or less.
By setting the numerical range of the various parameters of the elastic blade within the above range, stick-slip motion can be suppressed, and toner slippage at the blade contact portion can be suppressed.
Also, by providing a reinforcing means for dispersing and reinforcing the stress applied to the elastic blade portion in the vicinity of the tip ridge line that contacts the elastic blade of the support member, the stress concentrates on a part of the elastic blade and the elastic blade buckles. Can be prevented. By preventing buckling of the elastic blade, it is possible to prevent toner from slipping through the blade contact portion due to buckling and the inability to maintain linear pressure.

  According to the first to twelfth aspects of the present invention, the toner can be prevented from slipping through the blade contact portion, so that an excellent effect can be obtained even when a spherical toner is used. is there.

[Embodiment 1]
Hereinafter, an embodiment in which the present invention is applied to a printer which is an electrophotographic image forming apparatus (hereinafter referred to as Embodiment 1) will be described.
First, the configuration and operation of the entire printer according to the first embodiment will be described.
FIG. 2 is a schematic configuration diagram of the entire printer according to the first embodiment. This printer includes a photosensitive drum 1 as an image carrier that rotates in the direction of arrow A in the figure. The photosensitive drum 1 is formed by forming a photosensitive layer made of an organic photosensitive member on the outer peripheral surface of an aluminum substrate, the drum surface layer is made of polycarbonate, and the friction coefficient μ measured by the Euler belt method is 0. It is within the range of 3 ≦ μ ≦ 0.6. Around the photosensitive drum 1, there are a charging device 7 as a charging means, an exposure device 3 as a latent image forming means, a developing device 4 as a developing means, a transfer device 5 as a transferring means, and a cleaning as a cleaning means. A device 9 and a static elimination device 8 as a static elimination means are arranged. Further, the toner on the recording material P is located downstream of the transfer region in which the transfer is performed by the transfer device 5 in the recording material conveyance direction (in the direction of arrow B in the figure) in which the recording material P such as paper is conveyed. A fixing device 6 is provided as a fixing unit for fixing the image.

  The charging device 7 uniformly charges the surface of the photosensitive drum 1. The charging device 7 is arranged such that a charging member is brought into contact with the surface of the photosensitive drum 1 or a small gap is provided from the surface of the photosensitive drum 1 and a charging bias is applied to the charging member 7 to thereby surface the surface of the photosensitive drum 1. Are uniformly charged to a desired polarity and a desired potential. As this charging member, for example, a charging roller made of an elastic body, a scorotron charger using a wire electrode and a grid electrode, or the like can be used. The charging device 7 is not limited to such a configuration, and a widely known device can be used.

  The exposure device 3 forms an electrostatic latent image corresponding to image data on the surface of the photosensitive drum 1 charged by the charging device 7. The exposure apparatus 3 uses, for example, an LD (Laser Diode) or an LED (Light Emitting Diode) as a light emitting element, and irradiates light based on image data onto the uniformly charged surface of the photosensitive drum 1. As a result, an electrostatic latent image is formed on the surface of the photosensitive drum 1. The exposure apparatus 3 is not limited to such a configuration, and a widely known apparatus can be used.

  The developing device 4 performs development by attaching toner to the electrostatic latent image formed on the surface of the photosensitive drum 1. The developing device 4 includes a developing roller 4a as a developer carrier having a magnet roller as a magnetic field generating means arranged in a fixed manner. The developing roller 4 a rotates while carrying the developer on the surface thereof, thereby conveying the developer to a developing area facing the photosensitive drum 1. In the first embodiment, a two-component developer composed of a toner and a carrier is used as a developer, and a magnetic brush development method is used in which the carrier is sprinkled in a developing region by a magnetic force of a magnet roller and developed in a brush shape. . As the developer, a one-component developer composed only of toner without using a carrier may be used. A developing bias is applied to the developing roller 4a from a developing bias power source. As a result, a potential difference is generated between the potential on the surface of the developing roller 4a and the potential on the electrostatic latent image portion on the surface of the photosensitive drum 1 in the developing region. The toner in the agent adheres to the electrostatic latent image. As a result, the electrostatic latent image on the photosensitive drum 1 becomes a toner image. The developing device 4 is not limited to such a configuration, and a widely known device can be used.

  The transfer device 5 transfers the toner image on the photosensitive drum 1 onto the recording material P conveyed in the direction of arrow B in the drawing. The transfer device 5 brings a transfer member such as a transfer roller into contact with the surface of the photosensitive drum 1 with a predetermined pressing force, and forms a transfer nip between the transfer member and the photosensitive drum 1. Then, the toner on the surface of the photosensitive drum 1 is formed by a transfer electric field formed by applying a transfer bias having a polarity opposite to that of the toner from the transfer bias power source to the transfer member with the recording material P sandwiched by the transfer nip. The image is transferred onto the recording material P. As the transfer member, for example, a transfer roller or transfer belt made of an elastic body, or a scorotron charger using a wire electrode and a grid electrode can be used. The transfer device 5 is not limited to such a configuration, and a widely known device can be used. The recording material P onto which the toner image has been transferred in this manner is conveyed to the fixing device 6 where the toner image is fixed and then discharged outside the apparatus.

  The cleaning device 9 removes transfer residual toner remaining on the surface of the photosensitive drum 1 without being transferred from the surface of the photosensitive drum 1. The cleaning device 9 scrapes and removes the transfer residual toner on the surface of the photosensitive drum 1 by the cleaning blade 2 as an elastic blade. The transfer residual toner collected at the tip of the cleaning blade 2 falls into the cleaning device 9. Then, the toner is transported as waste toner to a waste toner bottle (not shown) by a toner transport mechanism (not shown) and stored therein. The waste toner stored in the waste toner bottle in this way is collected by a service person or the like. Note that the untransferred toner dropped into the cleaning device 9 may be conveyed to the developing device 4 as recycled toner and used again for development.

  The static eliminator 8 removes residual charges on the surface of the photosensitive drum. The surface of the photosensitive drum 1 from which the residual charge has been removed contributes to the next image formation. In addition, although this static elimination apparatus 8 employ | adopts the optical static elimination system using LED etc., it is not restricted to this.

  In recent years, in the image forming apparatus 100 that performs image formation using toner, there is an increasing demand for high resolution in order to form a high-precision and high-definition image. As a method for achieving high resolution, it is known that it is effective to use a spherical toner having a small particle diameter and a nearly spherical shape. Therefore, in the first embodiment, spherical toner having a toner particle size of 2.0 μm to 10 μm and a circularity of 0.98 or more is used to improve image quality. 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, a surfactant, preferably alkylbenzene sulfonate, is added as a dispersant, 0.1 to 0.5 [ml], 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 dispersion concentration becomes 3000 to 1 [10,000 / μl]. Set and measure toner shape and distribution. Based on the measurement result, the outer peripheral length of the actual toner projection shape shown in FIG. 3A is L1, and the projection area is S. The outer circumference of the perfect circle shown in FIG. L2 / L1 was determined when the length was L2, and the average value was defined as the circularity.

  As the spherical toner, it is possible to use an irregularly shaped toner (pulverized toner) whose shape is distorted by a pulverization method that has been widely used in the past, which has been spheroidized by heat treatment, or a toner manufactured by a polymerization method. The manufacturing method is not limited. In such a spherical toner, as described above, the conventional cleaning blade 2 used for removing the pulverized toner from the surface of the photosensitive drum 1 sufficiently removes the spherical toner from the surface of the photosensitive drum 1. There is a problem that cleaning failure occurs.

Accordingly, the present inventors have solved the problem that when the spherical toner is cleaned by the cleaning blade 2, the spherical toner slips through the contact portion between the cleaning blade 2 and the photosensitive drum 1 to cause a cleaning failure. In the counter-type cleaning blade 2, the inventors have made extensive studies on the cause of cleaning failure when spherical toner is used.
As a result, it was found that the minute vibration (stick slip) at the tip of the cleaning blade 2 is largely related to the defective cleaning of the spherical toner. Stick-slip is generated by the magnitude relationship between the frictional force (Fbp) acting between the photosensitive drum 1 and the cleaning blade 2 and the restoring force (Fbr) of the cleaning blade 2 that is an elastic body.
When the frictional force Fbp acting between the photosensitive drum 1 and the cleaning blade 2 and the elastic force Fbr of the cleaning blade 2 are Fbp> Fbr, the tip of the cleaning blade 2 is along the surface movement direction of the photosensitive drum 1. Move (stick).
When Fbp <Fbr, the photosensitive drum 1 moves (slips) in the direction opposite to the surface movement direction of the photosensitive drum 1. In the stick-slip motion of the cleaning blade 2, it was observed that the spherical toner slipped through the blade nip portion between the cleaning blade 2 and the photosensitive drum 1 when the cleaning blade 2 was slipping.

  On the other hand, when the pulverized toner that can be easily cleaned by the cleaning blade 2 was cleaned, it was observed that the occurrence of stick-slip was low and the blade nip was stable. That is, the spherical toner can be cleaned by reducing stick-slip generated when cleaning the spherical toner and forming a stable blade nip with little minute vibration. Specifically, the distance of reciprocation by the stick-slip motion of the cleaning blade 2 is short, and the occurrence of stick-slip can be reduced to prevent the spherical toner from slipping through. However, when the cleaning blade 2 made of an elastic member such as urethane rubber is pressed against the photosensitive drum 1, a stick-slip movement always occurs more or less. Therefore, we examined the case where spherical toner can be cleaned even when stick-slip occurs.

In order to examine the stick-slip motion in detail, the blade edge 2b where the cleaning blade 2 and the photosensitive drum 1 are in contact with each other is observed, and observation is performed using a high-magnification lens. FIG. 4A shows an outline of the observation result. The blade edge 2b is formed with a tip turning portion 2c by contact with the photosensitive drum 1, and a load applied to press the cleaning blade 2 against the photosensitive drum 1 is concentrated on the turning portion 2c. The cleaning blade 2 is in a stick state by the frictional force acting between the photosensitive drum 1 moving on the surface and the blade edge 2b, and moves along the surface movement direction of the photosensitive drum 1. When the restoring force of the cleaning blade 2 becomes greater than the frictional force, the cleaning blade 2 shifts to a slip state and moves in the direction opposite to the surface movement direction of the photosensitive drum 1. By such stick-slip motion, the blade edge 2 b reciprocates with respect to the surface movement direction of the photosensitive drum 1. At this time, an angle θ (actual cleaning angle: defined below) formed by the cleaning blade 2 and the photosensitive drum 1 also changes. As the stick state is reached, when the blade edge 2b is pulled along the surface movement direction of the photosensitive drum 1, θ decreases. On the other hand, during the slip movement, θ is larger than that in the stick state. The smaller the amplitude of the stick-slip motion of the cleaning blade 2, the smaller the change in the value of θ (= dθ). The present inventors consider that there is a correlation between the stability of cleaning by the cleaning blade 2 and stick-slip motion,
Stability ∝ (1 / dθ)
It was.
Here, the actual cleaning angle θ and the change amount dθ are defined as follows.
The actual cleaning angle θ was defined from an image obtained by observing the blade tip. That is, as shown in FIG. 4A, the angle formed by the tangent line between the spherical toner and the blade as a reference and the tangent line between the spherical toner and the photosensitive member is defined as the actual cleaning angle θ. Here, a spherical toner T having a particle diameter of 7 μm was used as a reference. Specifically, a 7 μm circle was applied to the observed image to determine the contact and tangent, and the actual cleaning angle θ was determined.
Further, as shown in FIGS. 4B and 4C, the actual cleaning angle change amount dθ is defined by the following equation from the maximum value θmax and the minimum value θmin of the actual cleaning angle θ during the cleaning operation.
dθ = θmax−θmin

  When cleaning the spherical toner, the toner hardly stays in the blade nip portion between the blade edge 2b and the photosensitive drum 1, and therefore the frictional force is reduced by the staying toner and the effect of suppressing stick-slip is hard to work. For this reason, stick slip tends to become more intense than when the pulverized toner is cleaned. The stick-slip motion of the cleaning blade 2 is complicatedly related to the influence of at least the cleaning blade 2, the photosensitive drum 1, and the toner.

  Therefore, the present inventors have examined a blade in which the cleaning blade 2 is difficult to perform stick-slip motion. Of the blade characteristics, we focused on the resilience and hardness that are closely related to stick-slip. As for the resilience, the higher the resilience, the more intense the stick-slip motion, and the lower the resilience, the more the stick-slip motion tends to be suppressed. Further, the higher the hardness is, the more the blade deformation is suppressed and the stick-slip motion tends to be suppressed.

[Experiment 1]
In order to reduce stick-slip by changing the physical property value of the blade, the following experiment was conducted to clarify the relationship between the physical property value of the blade and the stick-slip motion. The cleaning blade 2 having the shape shown in FIG. 12 is brought into contact with a transparent surface moving member having a friction coefficient equivalent to that of the photosensitive drum 1, and spherical toner is adhered to the surface moving body, and cleaning is performed with the cleaning blade 2. The cleaning property was evaluated. Further, in order to clarify the relationship between the resilience / hardness and the actual cleaning angle variation dθ, the variation in the actual cleaning angle θ during the cleaning of the blades (1) to (12) under the following experimental conditions. dθ was measured.
Experimental conditions:
Encroachment amount d = 1.0 [mm]
Surface moving body: μ = 0.3 to 0.6 (by Euler belt method)
Surface moving body linear velocity: 100 [mm / s]
Initial contact angle β = 20 [°]
Cleaning blade thickness t ₁ = 2.0 [mm]
Free length t ₂ = 7.0 [mm]

The cleaning properties shown in Table 1 were determined based on the following criteria for the amount of toner remaining on the surface of the image carrier after cleaning.
○: When completely cleaned.
(Triangle | delta): When a stripe-like cleaning defect generate | occur | produces partially, or when some toner remains on the whole surface.
X: When streaky or a large amount of toner remains on the entire surface.

From Table 1, blades (3), (7), (9), and (10) having a hardness of about 80 [°] and a rebound resilience of 30 [%] or less are fluctuation amounts of the actual cleaning angle during cleaning. When dθ is about 20 [°] or less, the amplitude of the stick-slip motion is small, indicating that the cleaning property is good. On the other hand, a blade having a rebound resilience of about 35% or more has a high dθ and a poor cleaning property. Therefore, it is considered that a cleaning property is advantageous by using a blade having a low rebound resilience.
Table 1 shows that the smaller the fluctuation amount dθ of the actual cleaning angle due to the stick-slip motion of the cleaning blade 2 and the more stable the tip behavior of the cleaning blade, the more advantageous it is for spherical toner cleaning.
On the other hand, as shown in Table 1 (1), (6), and (8), even when the actual cleaning angle variation dθ is 20 ° or less and the blade nip portion is stable, the cleaning property is good. It may not be possible.
In order to clarify this point, for the blades (1) to (12) shown in Table 1, the line when the initial contact angle β ₀ = 20 [°] and the biting amount is 1.0 [mm] is shown. The pressure and the linear pressure when the biting amount was 0.7 [mm] were measured, and the cleaning property was evaluated for each biting amount. The results are shown in Table 2.

Here, although the values of the resilience are close, the blades (1) and (3), the blades (6) and (7), and the blades (8) and (9) have different cleaning properties in Table 1. ).
When the blades (1) and (3) are compared, the linear pressure of (1) is 0.49 [N / cm] (50 [gf / cm]), the linear pressure of (3) is 0.7938 [N / cm] (81 [gf / cm]).
When the blades (6) and (7) are compared, the linear pressure of (6) is 0.6762 [N / cm] (69 [gf / cm]), and the linear pressure of (7) is 0.833. [N / cm] (85 [gf / cm]).
When the blades (8) and (9) are compared, the linear pressure of (8) is 0.7154 [N / cm] (73 [gf / cm]), and the linear pressure of (9) is 0.784. [N / cm] (80 [gf / cm]).
In either case, it is considered that the linear pressure is reduced due to the decrease in blade hardness.

Even when the blade slip is reduced and the blade nip is stable, if the blade linear pressure is low, the spherical toner pushes up the cleaning blade, which is an elastic body, and enters the blade nip, resulting in poor cleaning. . Accordingly, it is necessary to apply a load (linear pressure) to the blade to prevent the toner from entering the blade nip portion.
Spherical toner tends to slip into the blade nip as compared with conventional pulverized toner, and therefore, it is necessary to apply a larger load than conventional pulverized toner in order to suppress the entrapping of spherical toner.

The blade (4) has a hardness of 78 [°] and a linear pressure of 0.9604 [N / cm] (98 [gf / cm]), and the linear pressure sufficient to suppress the force of entering the spherical toner blade is sufficient. Has been granted. However, since the rebound resilience is high at 50%, stick stick is large and an unstable blade nip is formed, and it is considered that the spherical toner cannot be cleaned.
The blade (11), like the blade (4), has a linear pressure of 0.7938 [N / cm] (81 [gf / cm]), but the rebound resilience is 35 [%], and the stick of the blade It is considered that cleaning is poor due to the large slip movement.
On the other hand, even when the blades (3) and (7) showed good cleaning properties when the impact resilience of the blade was 20% or less and the biting amount d was 1.0 [mm], the blade bites into the image carrier. When the amount d was changed from 1.0 [mm] to 0.7 [mm], a cleaning failure occurred. This is because the linear pressure becomes 0.784 [N / cm] (80 g [f / cm]) or less by reducing the biting amount d, and the linear pressure necessary to prevent the spherical toner from slipping through is obtained. Because it was not possible.
From the above, in order to clean the spherical toner from the image bearing member whose friction coefficient on the surface of the image bearing member is μ = 0.3 to 0.6 (measured by the Euler belt method), the rebound resilience is 8.0. -30% (23 ° C), hardness 70-90 °, linear pressure 0.784 [N / cm] (80 [gf / cm]) or more are required.

Next, the shape of the cleaning blade 2 will be examined.
FIG. 5 shows a blade (hereinafter referred to as a conventional shape) having a shape in which a strip-shaped cleaning blade 2 is bonded to a metal support plate 3 as a blade support member used in Experiment 1 described above.
When cleaning is performed using the cleaning blade 2 having a conventional shape, stress concentrates on 2S in the drawing, which is a portion in the vicinity of the support plate edge 3b of the metal support plate 3 of the cleaning blade 2. If the strength of the stress-concentrated portion is not sufficient, the cleaning blade 2 may buckle at the stress-concentrated portion before reaching the expected life of the cleaning blade 2 and other members. If the cleaning blade 2 is buckled, a sufficient pressing force cannot be applied to the contact portion between the cleaning blade 2 and the photosensitive drum 1, the linear pressure at the contact portion cannot be maintained, and the spherical toner is trapped. Cannot be prevented.
For example, in the case of the blade (1) shown in Table 1, since the hardness is 70 [°], the biting amount d = 1.0 [mm] and the initial contact angle β = 20 [°] The linear pressure becomes 0.49 [N / cm] (50 [gf / cm]), and a sufficient linear pressure cannot be obtained to prevent the spherical toner from being trapped. Therefore, a cleaning blade that suppresses buckling by providing a reinforcing structure as a reinforcing means in a portion where stress is concentrated will be described.

  FIG. 1 is an enlarged view of the cleaning blade 2 applied to the first embodiment when viewed from the photosensitive drum axial direction, and FIG. 6 is an explanatory view of the cleaning blade 2 in FIG. As shown in FIG. 6, the cleaning blade 20 which is an elastic body has a generally convex shape with a thick portion 20γ at the center, a blade tip side thin portion 20α and a blade root side thin portion 20β at both ends. It consists of. Then, a stepped surface 20δ between the thick portion 20γ and the blade base thin portion 20β is supported by being in close contact with the tip surface of the metal support plate 3 (hereinafter referred to as a reinforcing shape). Yes. As shown in FIG. 6, a reinforcing structure that reinforces the cleaning blade 2 by dispersing the stress applied to the portion where the stress is concentrated in the vicinity of the support plate edge 3b of the metal support plate 3 if the stress is concentrated. By doing so, buckling of the cleaning blade can be suppressed.

[Experiment 2]
In Experiment 1, the linear pressure when a reinforcing structure was used for a rubber material for which a sufficient linear pressure could not be obtained with the blade of the conventional shape was measured. The experimental conditions are the same as in Experiment 1 except that the shape of the blade is different.
The results of Experiment 2 are shown in Table 1.
Same hardness as blade (1) of Experiment 1 70 [°], rebound resilience 8.0 [%]
Same hardness as blade (6) 71 [°], rebound resilience 17 [%]
Same hardness as blade (8) 72 [°], rebound resilience 23 [%]
When the three urethane elastomers were used and the shape was as shown in FIG. 6, the linear pressure was measured.
The lengths of the portions indicated by t in FIGS. 5 and 6 are t ₀ = 1.6 [mm], t ₁ = 2.0 [mm], t ₂ = 7.0 [mm], respectively. t ₃ = 11 [mm], t ₄ = 4.0 [mm], and t ₅ = 1.6 [mm].

As shown in Table 3, it is possible to easily increase the blade linear pressure in the blades (1), (6), and (8) by using a reinforced shape as compared with the conventional shape. A linear pressure of 0.784 [N / cm] (80 [gf / cm]) or more necessary to prevent toner from getting in can be obtained, and good cleaning can be achieved.
In addition, since the hardness of the cleaning blade itself is lower than that of the blade that showed good cleaning properties in Experiment 1, it can be more closely attached to the photosensitive drum than that having a high hardness, and good cleaning properties can be obtained. .

However, the linear pressure at the time of biting amount d = 1.0 [mm] in Table 3 is so high that it exceeds 1.176 [N / cm] (120 [gf / cm]) in any blade. It has become. If the linear pressure at the contact portion between the cleaning blade 20 and the photosensitive drum 1 is too high, the driving torque of the photosensitive drum 1 may increase or the life of each member may be shortened due to rubbing. It is not preferable. Therefore, the linear pressure at the contact portion between the cleaning blade 20 and the photosensitive drum 1 is 1.176 [N / cm] (120 [gf / cm]). In the first embodiment, the blade (1) in Table 3 employs a blade with a biting amount d = 0.7 [mm].
When the cleaning blade 2 has a conventional shape as shown in FIG. 5, the stress of the cleaning blade 2 in the vicinity of the support plate edge 3 b of the metal support plate 3 when the low-hardness elastic cleaning blade 2 is used. Buckling occurred at the concentrated portion 2S, and sufficient linear pressure was not applied to the blade tip. However, in FIG. 6, a thick portion 20γ is provided as a reinforcing structure for reinforcing the cleaning blade 2 by dispersing the stress applied to the portion of the cleaning blade 2 in the vicinity of the support plate edge 3 b of the metal support plate 3. . As a result, even when the blade (1), which is a low-hardness elastic member, is used, a sufficient linear pressure can be applied to the tip of the cleaning blade, and the occurrence of poor cleaning can be suppressed.

Next, an example of the configuration of the photosensitive drum 1 used in Embodiment 1 will be described.
The photosensitive drum 1 is a negatively charged organic photosensitive member, and a photosensitive layer or the like is provided on a drum-shaped conductive support 50 having a diameter of 30 [mm]. FIG. 8 is a cross-sectional view showing the photosensitive drum 1 used in the first embodiment. An undercoat layer 51 which is an insulating layer is provided on the conductive support 50 as a base layer. Further, a charge generation layer (CGL) 52 and a charge transport layer (CTL) 53 as a photosensitive layer are provided thereon. Furthermore, a surface protective layer (FR) 54 is laminated thereon.

As the conductive support 50, a conductive support having a volume resistance of 10 ¹⁰ Ω · cm or less can be used. For example, a metal such as aluminum, nickel, chromium, nichrome, copper, gold, silver, platinum, or a metal oxide such as tin oxide or indium oxide is coated on a film or cylindrical plastic or paper by vapor deposition or sputtering. Can be used, such as aluminum, aluminum alloy, nickel, stainless steel plates and the like, and pipes that have been surface treated by cutting, superfinishing, polishing, etc. . Further, an endless nickel belt and an endless stainless steel belt disclosed in Japanese Patent Application Laid-Open No. 52-36016 can also be used as the conductive support 50.
In addition to this, the conductive support 50 can also be obtained by coating conductive powder dispersed in an appropriate binder resin on the support. Examples of the conductive powder include carbon black, acetylene black, metal powder such as aluminum, nickel, iron, nichrome, copper, zinc and silver, or metal oxide powder such as conductive tin oxide and ITO. It is done. The binder resin used at the same time is polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer. , Polyvinyl acetate, polyvinylidene chloride, polyarylate resin, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly-N-vinylcarbazole, acrylic resin, silicone resin, epoxy resin, Examples thereof include thermoplastic, thermosetting resins, and photocurable resins such as melamine resin, urethane resin, phenol resin, and alkyd resin. Such a conductive layer can be provided by dispersing and coating these conductive powder and binder resin in a suitable solvent such as tetrahydrofuran, dichloromethane, methyl ethyl ketone, and toluene.
Furthermore, it is electrically conductive by a heat-shrinkable tube in which the conductive powder is contained in a material such as polyvinyl chloride, polypropylene, polyester, polystyrene, polyvinylidene chloride, polyethylene, chlorinated rubber, Teflon (registered trademark) on a suitable cylindrical substrate. Those provided with a conductive layer can also be used favorably as the conductive support 50 of the present invention.

Next, the photosensitive layer will be described. The photosensitive layer may be a single layer or a laminate, but for convenience of explanation, first, a case of a laminate configuration comprising a charge generation layer 52 and a charge transport layer 53 will be described.
The charge generation layer 52 is a layer mainly composed of a charge generation material. A known charge generation material can be used for the charge generation layer 52, and representative examples thereof include monoazo pigments, disazo pigments, trisazo pigments, perylene pigments, perinone pigments, quinacridone pigments, and quinone condensed polycyclic compounds. , Squaric acid dyes, other phthalocyanine pigments, naphthalocyanine pigments, azulenium salt dyes, and the like, which are useful. These charge generation materials can be used alone or in combination.
In the charge generation layer 52, a charge generation material is dispersed in a suitable solvent together with a binder resin as necessary using a ball mill, an attritor, a sand mill, ultrasonic waves, or the like, and this is dispersed on the conductive support 50 or below. It is formed by applying on the pulling layer 51 and drying.
In the charge generation layer 52, the charge generation material can be dispersed in a binder resin as necessary. Examples of binder resins that can be used include polyamide, polyurethane, epoxy resin, polyketone, polycarbonate, silicone resin, acrylic resin, polyvinyl butyral, polyvinyl formal, polyvinyl ketone, polystyrene, polysulfone, poly-N-vinylcarbazole, poly Examples include acrylamide, polyvinyl benzal, polyester, phenoxy resin, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyphenylene oxide, polyamide, polyvinyl pyridine, cellulose resin, casein, polyvinyl alcohol, and polyvinyl pyrrolidone. The amount of the binder resin is suitably 0 to 500 parts by weight, preferably 10 to 300 parts by weight with respect to 100 parts by weight of the charge generating material. The binder resin may be added before or after dispersion.
Examples of the solvent used here include isopropanol, acetone, methyl ethyl ketone, cyclohexanone, tetrahydrofuran, dioxane, ethyl cellosolve, ethyl acetate, methyl acetate, dichloromethane, dichloroethane, monochlorobenzene, cyclohexane, toluene, xylene, and ligroin. In particular, ketone solvents, ester solvents, and ether solvents are preferably used. These may be used alone or in combination of two or more.
The charge generation layer 52 includes a charge generation material, a solvent, and a binder resin as main components, and includes any additive such as a sensitizer, a dispersant, a surfactant, and silicone oil. Also good.
As a coating method for the coating solution, a dip coating method, spray coating, beat coating, nozzle coating, spinner coating, ring coating, or the like can be used. The film thickness of the charge generation layer 52 is suitably about 0.01 to 5 [μm], preferably 0.1 to 2 [μm].

Next, the charge transport layer 53 will be described. The charge transport layer 53 can be formed by dissolving or dispersing a charge transport material and a binder resin in an appropriate solvent, and applying and drying the solution on the charge generation layer 52. Further, if necessary, one or more plasticizers, leveling agents, antioxidants, etc. can be added. Charge transport materials include hole transport materials and electron transport materials.
Examples of the electron transporting material include chloroanil, bromoanil, tetracyanoethylene, tetracyanoquinodimethane, 2,4,7-trinitro-9-fluorenone, 2,4,5,7-tetranitro-9-fluorenone, 2,4 , 5,7-tetranitroxanthone, 2,4,8-trinitrothioxanthone, 2,6,8-trinitro-4H-indeno [1,2-b] thiophen-4-one, 1,3,7-tri Examples thereof include electron-accepting substances such as nitrodibenzothiophene-5,5-dioxide and benzoquinone derivatives.
Examples of hole transport materials include poly-N-vinylcarbazole and derivatives thereof, poly-γ-carbazolylethyl glutamate and derivatives thereof, pyrene-formaldehyde condensates and derivatives thereof, polyvinylpyrene, polyvinylphenanthrene, polysilane, oxazole derivatives, Oxadiazole derivatives, imidazole derivatives, monoarylamine derivatives, diarylamine derivatives, triarylamine derivatives, stilbene derivatives, α-phenylstilbene derivatives, benzidine derivatives, diarylmethane derivatives, triarylmethane derivatives, 9-styrylanthracene derivatives, pyrazolines Derivatives, divinylbenzene derivatives, hydrazone derivatives, indene derivatives, butadiene derivatives, pyrene derivatives, bisstilbene derivatives, enamine derivatives, etc. Other known materials may be used. These charge transport materials may be used alone or in combination of two or more.
As the binder resin, 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-vinyl carbazole, acrylic resin, silicone resin, epoxy resin, melamine resin, urethane resin And thermoplastic or thermosetting resins such as phenol resins and alkyd resins.
The amount of the charge transport material is appropriately 20 to 300 parts by weight, preferably 40 to 150 parts by weight, based on 100 parts by weight of the binder resin. The film thickness of the charge transport layer 53 is preferably 25 [μm] or less from the viewpoint of resolution and responsiveness. Regarding the lower limit, although it differs depending on the system to be used (particularly the charging potential), it is preferably 5 [μm] or more.
As the solvent used here, tetrahydrofuran, dioxane, toluene, dichloromethane, monochlorobenzene, dichloroethane, cyclohexanone, methyl ethyl ketone, acetone and the like are used. These may be used alone or in combination of two or more.

Next, the case where the photosensitive layer has a single layer structure will be described. The photosensitive layer is formed by dissolving or dispersing the above-described charge generation material, charge transport material, binder resin, etc. in an appropriate solvent, and applying and drying the solution on the conductive support 50 or the undercoat layer 51. it can. You may comprise from a charge generation material and binder resin, without containing a charge transport material. Moreover, a plasticizer, a leveling agent, antioxidant, etc. can also be added as needed.
As the binder resin, in addition to the binder resin previously mentioned in the charge transport layer 53, the binder resin mentioned in the charge generation layer 52 may be mixed and used. Of course, the polymer charge transport materials mentioned above can also be used favorably. The amount of the charge generating material with respect to 100 parts by weight of the binder resin is preferably 5 to 40 parts by weight, and the amount of the charge transporting material is preferably 0 to 190 parts by weight, and more preferably 50 to 150 parts by weight.
The photosensitive layer is formed by dip coating, spray coating, bead coating, a coating solution in which a charge generating material and a binder resin are dispersed together with a charge transporting material using a solvent such as tetrahydrofuran, dioxane, dichloroethane, and cyclohexane. It can be formed by coating with a ring coat or the like. The film thickness of the photosensitive layer is suitably about 5 to 25 [μm].

Next, the undercoat layer 51 will be described. In the photosensitive drum 1 according to Embodiment 1, an undercoat layer 51 can be provided between the conductive support 50 and the photosensitive layer. The undercoat layer 51 generally contains a resin as a main component. However, considering that the photosensitive layer is applied with a solvent on these resins, the undercoat layer 51 is a resin having a high solvent resistance with respect to a general organic solvent. Is desirable. Examples of such resins include water-soluble resins such as polyvinyl alcohol, casein, and sodium polyacrylate, alcohol-soluble resins such as copolymer nylon and methoxymethylated nylon, polyurethane, melamine resin, phenol resin, alkyd-melamine resin, and epoxy. Examples thereof include a curable resin that forms a three-dimensional network structure such as a resin. In order to prevent moire and reduce residual potential, the undercoat layer 51 may be added with fine powder pigments of metal oxides exemplified by titanium oxide, silica, alumina, zirconium oxide, tin oxide, indium oxide and the like. Further, the undercoat layer 51 can be formed using an appropriate solvent and a coating method like the above-described photosensitive layer. Furthermore, as the undercoat layer 51 of Embodiment 1, a silane coupling agent, a titanium coupling agent, a chromium coupling agent, or the like can also be used. In addition, in the undercoat layer 51 of Embodiment 1, Al ₂ O ₃ is provided by anodic oxidation, organic substances such as polyparaxylylene (parylene), SiO ₂ , SnO ₂ , TiO ₂ , ITO, an inorganic material such as CeO ₂ can be preferably used those provided by a vacuum thin-film forming method. In addition, known ones can be used. The thickness of the undercoat layer 51 is suitably 0 to 5 [μm].

Next, the structure which employ | adopted FR-OPC as a 1st Example of the protective layer 54 is demonstrated.
A protective layer 54 can be provided on the outermost surface layer of the photoreceptor to prevent mechanical wear. For example, a photoconductor surface-coated with amorphous silicon to improve wear resistance, or an organic photoconductor provided with an outermost surface layer in which alumina, tin oxide or the like is further dispersed on the surface of the charge transport layer 53, or the like is used. You can also.
As described above, the configuration of the photoreceptor 1 that can be used in the first embodiment is not limited to a specific configuration. A one-layer configuration in which only a photosensitive layer mainly composed of a charge generation material and a charge transport material is provided on the conductive support 50, or a charge generation layer mainly composed of a charge generation material on the conductive support 50 52 and a charge transporting layer 53 mainly composed of a charge transporting material, or a photosensitive layer mainly composed of a charge generating material and a charge transporting material is provided on the conductive support 50, on which Further, a structure in which a protective layer is provided, or a charge generation layer 52 mainly composed of a charge generation material and a charge transport layer 53 mainly composed of a charge transport material are laminated on the conductive support 50, and the charge transport. A structure in which a protective layer is provided on the layer 53, or a charge transport layer 53 mainly composed of a charge transport material and a charge generation layer 52 mainly composed of a charge generation material are laminated on the conductive support 50. Various layer configurations such as a configuration in which a protective layer is provided on the charge generation layer 52 It is applicable to photoreceptors having.

Next, a configuration in which super-FR-OPC is adopted as a second embodiment of the protective layer 54 will be described.
As the binder structure of the protective layer 54, a protective layer having a crosslinked structure is also effectively used. Regarding the formation of a cross-linked structure, a reactive monomer having a plurality of cross-linkable functional groups in one molecule is used to cause a cross-linking reaction using light or thermal energy to form a three-dimensional network structure. is there. This network structure functions as a binder resin and exhibits high wear resistance.
From the viewpoint of electrical stability, printing durability, and life, it is a very effective means to use a monomer having a charge transporting ability in whole or in part as the reactive monomer. By using such a monomer, a charge transporting site is formed in the network structure, and the function as a protective layer can be sufficiently expressed.
The reactive monomer having charge transporting ability includes a compound containing at least one charge transporting component and a silicon atom having a hydrolyzable substituent in the same molecule, and a charge transporting component in the same molecule. A compound containing a hydroxyl group, a compound containing a charge transporting component and a carboxyl group in the same molecule, a compound containing a charge transporting component and an epoxy group in the same molecule, a charge transporting component in the same molecule And a compound containing an isocyanate group. These charge transport materials having a reactive group may be used alone or in combination of two or more.
More preferably, a reactive monomer having a triarylamine structure is effectively used as the monomer having a charge transporting ability because of high electrical and chemical stability and high carrier mobility. Besides this, monofunctional and bifunctional polymerizable monomers and polymerizable oligomers are used in combination for the purpose of viscosity adjustment during coating, stress relaxation of the crosslinkable charge transport layer 53, low surface energy, and friction coefficient reduction. can do. As these polymerizable monomers and oligomers, known ones can be used.
In the present invention, the hole transporting compound is polymerized or cross-linked using heat or light. When the polymerization reaction is performed by heat, the polymerization initiator may be used in the case where the polymerization reaction proceeds only with thermal energy. Although it may be necessary, it is preferable to add an initiator in order to advance the reaction efficiently at a lower temperature.
In the case of polymerization by light, it is preferable to use ultraviolet light as light, but the reaction rarely proceeds only by light energy, and a photopolymerization initiator is generally used in combination. The polymerization initiator in this case mainly absorbs ultraviolet rays having a wavelength of 400 nm or less to generate active species such as radicals and ions, and initiates polymerization. In the present invention, the aforementioned heat and photopolymerization initiator can be used in combination.
The charge transport layer 53 having a network structure formed in this manner has high wear resistance, but has a large volume shrinkage during the crosslinking reaction, and if it becomes too thick, cracks and the like may occur. In such a case, the protective layer may be a laminated structure, a low molecular dispersion polymer protective layer may be used for the lower layer (photosensitive layer side), and a protective layer having a crosslinked structure may be formed on the upper layer (surface side). good.

The photosensitive drum 1 may be prepared in the same manner as in the first embodiment except that the protective layer coating solution and the film thickness / preparation conditions are changed as follows.
Methyltrimethoxysilane: 182 parts, dihydroxymethyltriphenylamine: 40 parts, 2-propanol: 225 parts, 2% acetic acid: 106 parts, aluminum trisacetylacetonate: 1 part are mixed to prepare a coating solution for the protective layer. Prepared. This coating solution was applied onto the charge transport layer 53 and dried, followed by heat curing at 110 ° C. for 1 hour to form a protective layer having a thickness of 3 μm.

The photosensitive drum 1 may be prepared in the same manner as in the first embodiment except that the protective layer coating solution and the film thickness / preparation conditions are changed as follows.
30 parts of the hole transporting compound represented by the chemical formula 1, 0.6 parts of the acrylic monomer and the photopolymerization initiator (1-hydroxy-cyclohexyl-phenyl-ketone) represented by the chemical formula 2, and 50 parts of monochlorobenzene / 50 parts of dichloromethane. It melt | dissolved in the mixed solvent and the coating material for the surface protective layers 54 was prepared. This paint was applied onto the charge transport layer 53 by spray coating, and cured for 30 seconds at a light intensity of 500 mW / cm ² using a metal halide lamp, thereby forming a surface protective layer 54 having a thickness of 5 μm.

Next, an example of the configuration of the charging device 7 used in the first embodiment will be described.
As a charging means, there has been conventionally used a corona charging method using corona discharge. In the corona charging method, a charge wire is disposed close to a member to be charged, and a high voltage is applied to the charge wire to cause a corona discharge between the charge wire and the member to be charged. Is charged. However, in the case of the corona charging method, discharge products such as ozone and nitrogen oxide (NOx) are generated with corona discharge. Since the discharge-generating substance may form a film of nitric acid or nitrate that adversely affects image formation on the surface of the photoreceptor, it is desirable to avoid the occurrence of the substance if possible.
Therefore, in recent years, in place of the corona charging method, the development of a contact charging method or a proximity charging method in which the generation of a discharge generating material is small and charging can be performed with low power has been active. In these methods, a charging member such as a roller, a brush, or a blade is brought into contact with or in close proximity to a charged member such as a photosensitive member, and a voltage is applied to the charging member to charge the surface of the charged member. It is. According to this method, compared to the corona charging method, the generation of a discharge generation material is small, and low power can be realized, so that the utility is high. In addition, since a large charging device is not required, the device can be miniaturized, which meets the needs for miniaturization of the device.

In the first embodiment, an example using the non-contact roller charging method shown below will be shown as an example to achieve the needs for low power, low hazard, and downsizing as described above.
When spherical toner is used, cleaning failure is likely to occur as compared with conventional pulverized toner as described above. Even in an image forming apparatus in which spherical toner is prevented from passing through the cleaning blade 2 and the photosensitive drum 1 as in the first embodiment, even if a cleaning failure should occur, the cleaning blade can be used as long as it is a non-contact roller charging system. Since the spherical toner that has passed through 2 does not adhere to the charging device 7, there is an advantage that an abnormal image does not occur due to an abnormal charging.
In the charging device 7 according to the first embodiment, the photosensitive member is charged by AC applied discharge by charging members arranged close to each other so as to be non-contact. There is a method in which the photosensitive member is charged by AC applied discharge by a charging member arranged in contact with and opposed to each other. When this method is applied, it is preferable to use an elastic member that improves the contact between the surface of the photoreceptor and the charging member and does not apply mechanical stress to the photoreceptor. However, when an elastic member is used, the charging nip width becomes wide, and the protective material may easily adhere to the charging roller side due to this. Therefore, it is more advantageous to charge the object to be charged without contact.

FIG. 9 is a schematic explanatory diagram of the charging device 7 and the photosensitive drum 1. The charging device 7 includes a charging roller 7a as a charging member, a spacer 22, a spring 15, and a power source 16. The charging roller 7a has a shaft portion 21a and a roller portion 21b as a charging portion. Among these, the roller portion 21b has a function of charging the surface of the photosensitive drum 1 so as to face the photosensitive drum 1, and is configured to be rotatable by the rotation of the shaft portion 21a. A spacer 22 as a gap holding member is provided on the charging roller so that the charging portion 21b on the surface of the charging roller 7a is opposed to the surface of the photosensitive belt with a small gap. By the spacer 22, a portion of the surface of the photosensitive drum 1 that faces the image forming area 11 where an image is formed is disposed so as not to contact the photosensitive drum 1. The length of the roller portion 21b in the longitudinal direction is set to be longer than the image forming area of the photosensitive drum 1, and the spacer 22 is brought into contact with the non-image forming area 12 of the photosensitive drum 1 so that the small gap is formed. 14 is formed. The charging roller 7a is rotated around the surface of the photosensitive drum 1 through the spacer 22 and rotated. The minute gap 14 is configured such that the closest portion between the charging roller portion 21b and the photosensitive drum 1 is 1 to 100 [μm].
The closest distance is more preferably 30 to 65 [μm]. In the apparatus of Embodiment 1, it arrange | positioned so that it might be set to 50 [micrometers]. A spring 15 for pressing the charging roller 7a toward the charged body is attached to the shaft portion 21a. As a result, the minute gap 14 can be maintained with high accuracy.
The charging roller 7a is connected to a power source 16 for charging, and uniformly charges the surface of the photosensitive drum 1 by AC applied discharge in a minute gap between the surface of the photosensitive drum 1 and the surface of the charging roller 7a. In the first embodiment, an alternating voltage in which an AC voltage that is an AC component is superimposed on a DC voltage that is a DC component is applied to the charging portion of the charging roller 7a. By using the alternating voltage, the influence of variations in charging potential caused by minute gap fluctuations is suppressed, and uniform charging becomes possible.

The charging roller 7a includes a cored bar as a conductive support having a cylindrical shape, and a resistance adjusting layer formed on the outer peripheral surface of the cored bar. In the first embodiment, the charging roller 7a has a diameter of 10 [mm].
For example, a known material such as a rubber member can be used for the surface of the charging roller 7a, but it is more preferable to use a resin material. This is because, when a rubber member is used, it is difficult to maintain a minute gap with respect to the photosensitive drum 1 due to water absorption of the rubber and generation of deflection. Depending on the image forming conditions, only the central portion of the charging roller 7a may suddenly contact the surface of the photoreceptor. It is difficult to cope with such disturbance of the surface layer of the photosensitive member due to the local and sudden contact of the charging roller 7a with the photosensitive drum 1. Therefore, when charging the photoconductor by the non-contact charging method, it is more preferable to use a hard material capable of maintaining a small gap between the charging roller 7a and the photoconductor drum 1 uniformly.

Next, the surface layer of the charging roller 7a will be described.
As a material whose surface of the charging roller 7a is hard, for example, the following can be used. The resistance adjustment layer is formed from a thermoplastic resin composition (polyethylene, polypropylene, polymethyl methacrylate, polystyrene, or a copolymer thereof, etc.) in which a polymer type ion conductive agent is dispersed, and the surface of the resistance adjustment layer is formed with a curing agent. For example, a cured film. The cured film treatment can be performed, for example, by immersing the resistance adjusting layer in a treatment solution containing an isocyanate-containing compound. Alternatively, a cured film layer may be formed again on the surface of the resistance adjustment layer.

Further, as shown in FIG. 10, the image forming apparatus 100 of Embodiment 1 includes a process cartridge 200 that integrally includes at least the cleaning blade 2 and the photosensitive drum 1. By using the process cartridge 200, the user can easily replace the blade when the blade life and the image carrier life are reached.
Further, the process cartridge 200 has a heat insulating structure, and the temperature variation in the process cartridge 200 that is an environment in which the cleaning blade 2 is used is reduced. When urethane rubber or the like is used for the cleaning blade 2, cleaning properties are affected by changes in the resilience of the rubber, particularly due to environmental changes. Therefore, since the process cartridge 200 has a heat insulating structure, it is possible to minimize the deterioration of the cleaning property due to environmental fluctuations. As the heat insulating structure, various heat insulating sheets and methods such as stretching a foam material in the cartridge case are simple, but are not limited to the above methods.

As described above, according to the first embodiment, the thickened portion 20γ with the blade thickness increased as a reinforcing means at the substantially central portion and the blade tip side thinned portion 20α at both ends so that the sectional shape of the cleaning blade 2 is substantially convex. It consists of a blade root side thin part 20β. The metal support plate 3 is in close contact with and bonded to the blade side surface of the blade base side thin portion 20β. The stepped surface 20 δ of the thick portion 20 γ is in a shape (hereinafter referred to as a reinforcing shape) supported by being in close contact with the tip surface of the metal support plate 3. As shown in FIG. 6, the stress applied to the stress concentration portion 2S in FIG. 5 where the stress was concentrated in the conventional shape shown in FIG. 5 is distributed to the contact portion between the step surface 20δ and the tip surface of the metal plate. The buckling of the cleaning blade 2 can be suppressed by providing the reinforcing structure. Further, the rebound resilience at 23 ° C. of the cleaning blade 2 is 8.0 [%] within the range of 8.0 [%] to 30 [%], and the JISA hardness is 70 [°] and 70 [°] or higher. The linear pressure at the contact portion with the photosensitive drum 1 is 1.0682 [N / cm] (109 gf / cm) and is 0.784 [N / cm] or more and 1.176. [N / cm] or less (80 [gf / cm] or more and 120 [gf / cm] or less). By using a cleaning blade having such physical property values, it is possible to suppress slipping of the spherical toner, and good cleaning can be performed.
In addition, by using a polyurethane elastomer as an elastic body forming the cleaning blade 2, good cleaning can be performed.
Further, since the photosensitive drum 1 has the protective layer 54 in which inorganic fine particles such as alumina and tin oxide are dispersed and contained, the wear resistance of the surface of the photosensitive drum 1 is improved and toner slipping is prevented. Even if the linear pressure is increased, the member life of the photosensitive drum 1 can be maintained.
Further, since the binder resin of the protective layer 54 of the photosensitive drum 1 has a cross-linked structure, the abrasion resistance of the photosensitive drum 1 is improved, and even if the linear pressure is increased to prevent the toner from slipping, the photosensitive drum 1 can be exposed to light. The member life of the body drum 1 can be maintained. Furthermore, by having a charge transport site in the structure of the binder resin, the performance of the protective layer 54 can be improved, and the member life of the photosensitive drum 1 can be further maintained.
Further, when at least the cleaning blade 2 and the photosensitive drum 1 are integrated to form the process cartridge 200, the user can easily replace the blade when the blade life and the image carrier life are reached.
In addition, by making the process cartridge 200 a heat resistant structure, the rebound resilience of the rubber changes due to environmental fluctuations caused by temperature changes in particular, thereby affecting the cleaning performance and reducing the cleaning performance due to environmental fluctuations. Can be minimized.

[Modification 1]
In the first embodiment, as the reinforcing structure, the thick portion 20γ is provided near the center of the cleaning blade 20 to suppress the occurrence of buckling. However, the reinforcing structure is not limited to this. As the reinforcing structure, a reinforcing member may be provided in the direction from the stress concentration portion 2S in FIG. A configuration provided with a reinforcing member for the cleaning blade 2 is shown in FIGS.
In FIG. 7A, a reinforcing member 30A having the same thickness as that of the metal support plate 3 is provided so that the free length t ₆ of the cleaning blade 30 that is an elastic body is 3.0 [mm]. The reinforcing member 30A may be made of a material different from or the same as that of the metal support plate 3, and is in close contact with and adhered to at least the side surface of the cleaning blade 2. As a material of the reinforcing member 30A, it is desirable to use a material having a hardness lower than that of the metal support plate 3 and higher than that of the cleaning blade 30. It may be selected length of the free length t ₆ as appropriate, not as far as the above.
In FIG. 7B, a reinforcing member 40A thinner than the thickness of the metal support plate 3 is attached to the cleaning blade 40 that is an elastic body. In the drawing, the reinforcing member 40A is pasted up to the forefront of the cleaning blade 40, but this is not restrictive, and the length of the reinforcing member 40A may be set arbitrarily.
The configuration of Modification 1 shown in FIGS. 7A and 7B is a configuration in which a reinforcing member is provided as a reinforcing structure on the cleaning blade 2 having the conventional shape shown in FIG. With this configuration, the cleaning property of the conventional cleaning blade can be improved with an easy configuration in which a reinforcing member is provided on the conventional cleaning blade 2.
Further, the reinforcing structure shown in FIGS. 6 and 7 is not limited to a material whose cleaning property is not sufficient due to the low hardness in Experiment 1, and a material which has sufficient cleaning property may be used. Even when a material having high hardness is used, there is a risk of buckling. Therefore, by employing the above-described reinforcing structure, a more reliable cleaning device can be obtained.

[Modification 2]
Further, in the conventional shape shown in FIG. 5, the thickness is t ₁ = 2 [mm] to 2.5 [mm] or more: for example, 2.8 [mm], 3.0 [mm], 3 .6 [mm], etc., and by adjusting the biting amount d as appropriate, even if the blade is made of the urethane elastomer used in the blades (1), (6), (8), etc., the line necessary for cleaning the spherical toner A pressure of 0.784 [N / cm] (80 [gf / cm]) can be obtained.

[Modification 3]
In the first embodiment, the stick-slip motion of the cleaning blade is suppressed by using a member having low rebound resilience, but the present invention is not limited to this. Hereinafter, Modification 3 will be described in which stick slip is reduced by reducing the coefficient of friction of the surface of the photosensitive drum 1 as an image carrier.
FIG. 11 is a schematic configuration diagram of the entire printer according to the modified example 3 provided with the lubricant application device 10 as the lubricant application means for applying the lubricant in order to reduce the friction coefficient of the surface of the photosensitive drum 1. .
In the first embodiment, in order to reduce the stick-slip motion of the cleaning blade, the rebound resilience and hardness of the cleaning blade are set to be low repulsion and high hardness, respectively, compared to the conventional pulverized toner blade, thereby cleaning the spherical toner. It has good characteristics.
On the other hand, in Modification 3, the lubricant is molded into a solid lubricant to form a solid lubricant 32, and the solid lubricant 32 is pressed against the fur brush 31 rotated by the pressurizing spring 33, and the photoreceptor is passed through the fur brush 31. It is applied to the drum 1. By applying a lubricant to the surface of the photosensitive drum 1 as an image carrier and reducing the friction coefficient, the stick-slip motion of the cleaning blade 2 is further suppressed by the configuration of the first embodiment. The amplitude of the stick-slip motion of the cleaning blade 2, which is a particular problem when using spherical toner, greatly depends on the frictional force between the cleaning blade 2 and the photosensitive drum 1. Therefore, the stick slip of the cleaning blade 2 can be significantly suppressed by reducing the coefficient of friction on the surface of the photosensitive drum 1.

実験１、２より、球形トナーがクリーニング可能な条件を満たす表４に示すブレードについて、低摩擦係数化する前の像担持体と、低摩擦係数化した像担持体での実クリーニング角ｄθを測定した。その結果、各ブレードとも、低摩擦係数化した像担持体を用いることにより、スティックスリップが抑制され、ｄθが小さくなることが分かる。
これは、像担持体の低摩擦係数化により、クリーニングブレードと像担持体間の摩擦力が小さくなり、スティックスリップ運動が低減されているからである。 [Experiment 3]
Under the following experimental conditions, when the lubricant is applied to the photoreceptor in the reinforcing shape of blades (1) and (6) in Table 2 and the conventional shapes of blades (3) and (7) in Table 1; The variation dθ of the actual cleaning angle θ during cleaning in the same surface state was measured. Here, the shape shown in FIG. 62 of Embodiment 1 was used as the reinforcing shape.
Experimental conditions:
Surface moving body surface: μ = 0.2 or less (by Euler belt method)
Surface moving body linear velocity: 100 mm / s
Initial contact angle β = 20 °
Table 4 compares the cleaning angle variation dθ measured in Experiment 3 with the cleaning angle variation dθ in Experiment 1 or 2 under the same conditions except that the friction coefficient of the surface moving body was reduced. is there.

From Experiments 1 and 2, for the blade shown in Table 4 that satisfies the condition that the spherical toner can be cleaned, the actual cleaning angle dθ between the image carrier before the reduction of the friction coefficient and the image carrier having the reduced friction coefficient is measured. did. As a result, it is understood that stick slip is suppressed and dθ is reduced by using an image carrier having a low friction coefficient for each blade.
This is because the frictional force between the cleaning blade and the image carrier is reduced by reducing the friction coefficient of the image carrier, and the stick-slip motion is reduced.

As the lubricant, a lamellar crystal powder such as zinc stearate is preferably used. A lamellar crystal has a layered structure in which amphiphilic molecules are self-organized, and when a shearing force is applied, the crystal breaks along the layers and is slippery. This action is considered to be effective in reducing the friction coefficient. In addition, it is also possible to use other substances such as various fatty acid salts, waxes, and silicone oils as lubricants.
Examples of fatty acids include undecyl acid, lauric acid, tridecyl acid, myristic acid, palmitic acid, pendadecyl acid, stearic acid, heptadecyl acid, arachidic acid, montanic acid, oleic acid, arachidonic acid, caprylic acid, capric acid, caproic acid, etc. Examples of the metal salt include salts with metals such as zinc, iron, copper, magnesium, aluminum, and calcium.

As described above, stick-slip motion can be suppressed and a more stable blade nip can be formed compared to the case where a lubricant is applied by the lubricant application device 10 on the surface of the photosensitive drum 1 as an image carrier. Therefore, the toner can be prevented from slipping through and the cleaning property can be improved.
Further, since the adhesion force of the toner to the image carrier can be reduced, the spherical toner can be cleaned more easily.

  In Modification 3, the lubricant is applied in order to reduce the coefficient of friction on the surface of the image carrier. However, the present invention is not limited to this, and a substance having a low friction coefficient is internally added to the surface of the image carrier. Alternatively, the same effect can be obtained by adding a lubricating substance to the toner and applying it to the surface of the image carrier through the toner.

FIG. 3 is an enlarged view of a cleaning blade included in a cleaning device included in the printer according to the first embodiment when viewed from the photosensitive drum axial direction. 1 is a schematic configuration diagram of an entire printer according to a first embodiment. (A) And (b) is explanatory drawing for demonstrating the measuring method of circularity. (A), (b) and (c) is explanatory drawing for demonstrating real cleaning angle (theta) and variation | change_quantity d (theta). Explanatory drawing of the blade of a conventional shape. FIG. 3 is an explanatory diagram of a reinforcing blade according to the first embodiment. (A) And (b) is explanatory drawing of the braid | blade of the reinforcement shape which concerns on the modification 1. FIG. Sectional drawing of a photoreceptor. FIG. 3 is a schematic explanatory diagram of a charging device and a photoreceptor. FIG. 3 is a cross-sectional view illustrating a schematic configuration of a process cartridge that can be attached to and detached from the printer according to the first embodiment. . FIG. 10 is a schematic configuration diagram of an entire printer according to a third modification. Explanatory drawing for demonstrating arrangement | positioning of the cleaning blade with respect to the conventional photoreceptor drum (image carrier). FIG. 4 is a cross-sectional view of the blade tip portion deformed from the photosensitive drum axial direction when the cleaning blade is brought into contact with the biting amount while the photosensitive drum is stationary. FIG. 14 is a cross-sectional view of a deformed state of a blade tip when the surface of the photosensitive drum 1 is moved in the direction of an arrow A in the state shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photosensitive drum 2 Cleaning blade 3 Metal support plate 4 Developing apparatus 5 Transfer apparatus 6 Fixing apparatus 7 Charging apparatus 8 Static elimination apparatus 9 Cleaning apparatus 10 Lubricant coating apparatus 100 Image forming apparatus 200 Process cartridge

Claims (12)

An image carrier that carries a toner image on the surface and moves; and
Unnecessary toner adhering to the surface of the image carrier is removed from the surface of the image carrier using an elastic blade supported by a support member so that a predetermined range including the edge of the tip contacts the surface of the image carrier. In an image forming apparatus provided with a cleaning device,
The elastic blade is disposed in contact with the counter direction with respect to the surface movement direction of the image carrier,
A reinforcing means for reinforcing the elastic blade portion by dispersing stress applied to the elastic blade portion in the vicinity of the leading edge ridge line of the support member in contact with the elastic blade;
The elastic body forming the elastic blade has a rebound resilience at 23 ° C. of 8.0 [%] or more and 30 [%] or less, a JISA hardness of 70 [°] or more and 90 [°] or less, and the image carrier The pressing force per unit length in the axial direction (hereinafter referred to as linear pressure) applied to a predetermined range in contact with the surface is 0.784 [N / cm] or more and 1.176 [N / cm] or less (80 [ gf / cm] or more and 120 [gf / cm] or less). The image forming apparatus according to claim 1.
Increase the thickness at least partially from the middle of the elastic blade from the rear end to the tip,
The elastic blade is attached to the support member so that the stepped surface of the thickened portion is in close contact with the tip surface of the support member, and the reinforcing means is configured by the thickened portion. An image forming apparatus. The image forming apparatus according to claim 1.
To the side surface of the elastic blade on the support member side, the rear end surface is in close contact with the front end surface of the support member.
An image forming apparatus, wherein a reinforcing member as the reinforcing means is fixed. The image forming apparatus according to claim 1.
An image forming apparatus, wherein the elastic body forming the elastic blade is a polyurethane elastomer. The image forming apparatus according to claim 1, wherein:
An image forming apparatus, wherein a lubricant is added to the toner for forming the toner image. The image forming apparatus according to claim 1, wherein:
An image forming apparatus comprising: a lubricant applying means for applying a lubricant to the surface of the image carrier. The image forming apparatus according to claim 1, wherein:
An image forming apparatus, wherein a lubricating material is internally added to the outermost layer of the image carrier. The image forming apparatus according to claim 1.
An image forming apparatus, wherein the image carrier has a protective layer containing inorganic differential particles. The image forming apparatus according to claim 1.
An image forming apparatus, wherein the image carrier is provided with a protective layer, and the binder resin of the protective layer has a crosslinked structure. The image forming apparatus according to claim 9.
An image forming apparatus comprising a charge transport site in the structure of the binder resin having the crosslinked structure of the protective layer. The image forming apparatus according to claim 1.
An image forming apparatus comprising: a process cartridge that integrally supports the image carrier and the cleaning device and is detachable from a main body of the image forming apparatus. The image forming apparatus according to claim 11.
An image forming apparatus, wherein the process cartridge has a heat insulating structure.

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