JP2012150203A - Image forming device and process cartridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device and a process cartridge having a cleaning blade capable of preventing separation of a tip ridge part and improving followability for an image carrier to be cleaned of the tip ridge part to maintain contact pressure.SOLUTION: A cleaning blade 62 comprises a strip-like elastic blade 622 having a width corresponding to a length in a direction orthogonal to a moving direction of a photoreceptor 3 and a surface layer 623, which is formed in a region including an edge in contact with the photoreceptor 3 of the tip surface 62a in the elastic blade 622 and having a predetermined area based on the area of the tip surface 62a, is harder than the elastic blade 622 and has a layer thickness of 0.1 to 2 μm. The cleaning blade 62 is in contact with the photoreceptor 3 by setting a cleaning angle which is an angle formed by the tip surface on which the surface layer 623 is formed and the surface of the photoreceptor 3 at 80 to 85 degrees and linear pressure with respect to the surface of the photoreceptor 3 at 10 to 15 g/cm.

Description

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

  Conventionally, in an electrophotographic image forming apparatus, unnecessary transfer residual toner adhering to a surface after transferring a toner image to a transfer paper or an intermediate transfer member is cleaned on an image carrier such as a photosensitive member as a member to be cleaned. It is removed by means of a cleaning device.

  As a cleaning member of this cleaning device, one that uses a strip-shaped cleaning blade is well known because it can generally be simplified in configuration and has excellent cleaning performance. This cleaning blade is composed of a strip-shaped elastic body such as polyurethane rubber. Then, the base end of the cleaning blade is supported by a support member, and the leading edge portion is pressed against the peripheral surface of the image carrier, and the toner remaining on the image carrier is damped and scraped off and removed.

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

  In order to suppress such slip-through, it is necessary to increase the cleaning pressure by increasing the contact pressure between the image carrier and the cleaning blade. However, when the contact pressure of the cleaning blade is increased, the frictional force between the image carrier 3 and the cleaning blade 92 increases as shown in FIG. 8A, and the cleaning blade 92 is pulled in the moving direction of the image carrier 3. As a result, the leading edge portion 92c of the cleaning blade 92 is turned up. When the turned cleaning blade 92 is restored to the original state against the turn, abnormal noise may occur. Further, when the cleaning is continued with the leading edge portion 92c of the cleaning blade 92 turned up, as shown in FIG. 8B, the cleaning blade 92 is separated from the leading edge portion 92c of the leading edge surface 92b by several [μm]. Local wear will occur at the site. If the cleaning is further continued in such a state, this local wear increases, and eventually, the leading edge line 92c is lost as shown in FIG. 8C. If the leading edge portion 92c is missing, the toner cannot be properly cleaned, resulting in poor cleaning.

  Patent Document 1 describes that a cleaning blade made of polyurethane elastomer is provided with a surface layer made of a resin having a film hardness of pencil hardness B to 6H on at least the contact portion. By providing a surface layer having a film hardness of pencil hardness B to 6H that is harder than the rubber member, the friction coefficient of the cleaning blade contact portion can be lowered, and the wear resistance of the cleaning blade can be increased. Further, it is possible to reduce the frictional force between the image carrier and the cleaning blade, and it is possible to satisfactorily suppress the turning of the edge portion of the cleaning blade. Furthermore, since the surface layer of the pencil hardness of pencil hardness B to 6H is hard and hardly deformed, it is possible to further suppress the turning of the tip ridge line portion of the cleaning blade.

  Patent Document 2 describes a cleaning blade in which a silicon-containing ultraviolet curable material is impregnated into an elastic blade to swell and then subjected to ultraviolet irradiation to form a cured layer on the surface. As described above, even by providing a hardened layer having a hardness higher than that of the elastic blade made of an ultraviolet curable material, the wear resistance can be improved and the turning of the tip ridge line portion of the cleaning blade can be suppressed.

However, even with a cleaning blade provided with a surface layer or a hardened layer as described above, a cleaning failure occurs under severe conditions such as during continuous solid image formation where the amount of powder formed on the image carrier is very large. There was a case.
Also, in an image forming apparatus having a lubricant application mechanism, viscosity is generated due to charge deterioration of the lubricant applied on the photosensitive member, particularly with a charging device using a charging roller, and as an adverse effect, the image bearing of the edge portion of the cleaning blade is carried. By reducing the followability to the body surface, a cleaning defect may occur as well.

  The present invention has been made in view of the above-described problems in the prior art, suppresses turning of the tip ridge line portion, and improves the followability of the tip ridge line portion with respect to the image carrier, thereby maintaining the contact pressure. An object of the present invention is to provide an image forming apparatus having a cleaning blade and a process cartridge.

The inventors confirmed the above-mentioned problem phenomenon by an experiment described later. This is considered to be due to the following reasons. That is, since the surface layer is provided over the longitudinal direction of the front end surface of the rubber member, the elasticity of the rubber member is hindered by the influence of the surface layer, and the followability of the front edge line portion of the cleaning blade to the image carrier surface is improved. However, when the image carrier is decentered or there is a slight undulation on the surface of the image carrier, the contact pressure varies. Further, when a large amount of toner is blocked by the cleaning blade, such as during continuous solid image formation, the pressing force to the cleaning blade by the blocked toner is high. Therefore, when the contact pressure of the cleaning blade with the image carrier fluctuates and the contact pressure decreases, the pressing force by the toner exceeds the contact pressure, and the toner slips through the cleaning blade. It is considered that defective cleaning has occurred under severe conditions such as during continuous solid image formation where the amount of powder formed on the carrier is very large.
Based on these findings, the inventors have intensively studied to solve the problem of poor cleaning and have come to achieve the present invention.

That is, the present invention provided to solve the above problems is as follows. In addition, the site | part and code | symbol etc. which respond | correspond in the form for implementing this invention in a parenthesis are shown.
[1] Image carrier (photoconductor 3), charging means (charging device 4) for charging the surface of the image carrier, and latent image forming means for forming an electrostatic latent image on the surface of the charged image carrier. A developing means (developing device 5) for developing the electrostatic latent image formed on the surface of the image carrier into a toner image; and a transferring means (transfer device) for transferring the toner image on the surface of the image carrier to a transfer body. 7) and a cleaning unit (cleaning device 6) having a cleaning blade (cleaning blade 62) that contacts the surface of the image carrier and removes residual toner attached to the surface of the image carrier. The cleaning blade includes a strip-shaped elastic substrate (elastic blade 622) having a width corresponding to a length in a direction perpendicular to the moving direction of the image carrier, and a tip of the elastic substrate. Surface (tip surface 62a) A surface layer (including an end contacting the image carrier and having a predetermined area on the basis of the area of the tip surface, which is harder than the elastic substrate and has a layer thickness of 0.1 to 2 μm) A surface layer 623), a cleaning angle that is an angle formed by a tip surface on which the surface layer is formed and the surface of the image carrier is 80 to 85 degrees, and a linear pressure on the surface of the image carrier is 10 to An image forming apparatus that is in contact with the image carrier at 15 g / cm (FIGS. 1, 3 to 6).
[2] The surface layer includes a tip surface (tip surface 62a) that forms a tip ridge line portion (tip ridge line portion 62c) on the end side that contacts the image carrier of the elastic base material, and the image carrier. The image forming apparatus according to [1], wherein the image forming apparatus is formed on a part of each of a blade lower surface (blade lower surface 62b) which is a main surface facing the body (FIGS. 3B and 4). .
[3] The image forming apparatus according to [2], wherein the surface layer is formed in a region that is substantially half of a total length in the thickness direction of the elastic base material on the tip surface.
[4] The image formation according to [2] or [3], wherein an area of the surface layer formed on the lower surface of the blade is substantially the same as an area of the surface layer formed on the tip surface. apparatus.
[5] The image forming apparatus according to [1], wherein the surface layer is formed only on the entire front end surface of the elastic substrate (FIGS. 5B and 6).
[6] The image forming apparatus according to any one of [1] to [5], wherein the elastic base material is made of rubber containing a urethane group.
[7] Image carrier (photoconductor 3), charging means for charging the surface of the image carrier (charging device 4), and latent image forming means for forming an electrostatic latent image on the surface of the charged image carrier. A developing means (developing device 5) for developing the electrostatic latent image formed on the surface of the image carrier into a toner image; and a transferring means (transfer device) for transferring the toner image on the surface of the image carrier to a transfer body. 7) and a cleaning unit (cleaning device 6) having a cleaning blade (cleaning blade 62) that contacts the surface of the image carrier and removes residual toner attached to the surface of the image carrier. In the process cartridge that is detachably attachable to and integrally supports the image carrier and the cleaning means, the cleaning blade has a width corresponding to a length in a direction perpendicular to the moving direction of the image carrier. Short with A booklet-shaped elastic base material (elastic body blade 622) and a tip surface of the elastic base material (tip surface 62a) including an end portion that comes into contact with the image carrier and based on the area of the tip surface A surface layer (surface layer 623) which is formed in a region of a predetermined area and is harder than the elastic base material and has a layer thickness of 0.1 to 2 μm, and the tip surface on which the surface layer is formed and the image A process in which a cleaning angle, which is an angle formed by the surface of the carrier, is 80 to 85 degrees, and a linear pressure with respect to the surface of the image carrier is 10 to 15 g / cm, and is in contact with the image carrier. Cartridge (process cartridge 1, FIG. 1).

According to the image forming apparatus of the present invention, it is possible to form a surface layer in a region having a predetermined area with respect to the area of the tip surface of the elastic base material, thereby imparting appropriate rigidity and flexibility to the cleaning blade. Therefore, when the cleaning blade is brought into contact with the image carrier under a predetermined condition, it prevents the tip ridge line portion from moving in the moving direction of the image carrier, and suppresses erosion wear, It is possible to prevent the generation of abnormal noise without causing filming on the image carrier. Furthermore, since the contact portion (tip ridge line portion) of the elastic substrate follows the surface shape change of the image carrier, the tip ridge line portion, that is, the surface layer is always at a predetermined pressure in the entire width of the image carrier. It comes into contact, and good cleaning properties can be maintained for a long time without damaging the surface of the image carrier.
According to the process cartridge of the present invention, the above-described cleaning blade and the image carrier can be attached to and detached from the image forming apparatus while being held in contact with each other under a predetermined condition.

1 is a schematic configuration diagram of a printer that is an embodiment of an image forming apparatus according to the present invention. It is an explanatory diagram of a method for measuring the circularity of the toner. It is a perspective view showing a basic configuration example (1) of a cleaning blade used in the image forming apparatus according to the present invention. 1 is an enlarged cross-sectional view illustrating a configuration of a first embodiment of an image forming apparatus according to the present invention. It is a perspective view showing a basic configuration example (2) of a cleaning blade used in the image forming apparatus according to the present invention. FIG. 4 is an enlarged cross-sectional view illustrating a configuration of a second embodiment of an image forming apparatus according to the present invention. It is a schematic diagram which shows the measurement location of the abrasion width | variety of the elastic body blade in an Example. It is sectional drawing which shows the state in the ridgeline part of the front-end | tip of the conventional cleaning blade.

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

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

  Around the photosensitive member 3, a charging device 4 as a charging unit, a developing device 5 as a developing unit that converts a latent image into a toner image, a transfer device 7 as a transfer unit that transfers a toner image onto a transfer sheet as a recording medium, Cleaning device 6 as a cleaning means for cleaning toner remaining on the photoreceptor 3 after transfer, lubricant application device 10 as a lubricant application means for applying a lubricant on the photoreceptor 3, and a static elimination lamp for eliminating the charge on the photoreceptor 3. (Not shown) etc. are arranged. Reference numeral 14 denotes a transfer belt.

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

For the charging device 4, known means such as a corotron, a scorotron, and a solid state charger (solid state charger) are used.
Among these charging methods, the contact charging method or the non-contact proximity arrangement method is more desirable, and has advantages such as high charging efficiency, a small amount of ozone generation, and miniaturization of the apparatus.

  In addition, light sources such as fluorescent lamps, tungsten lamps, halogen lamps, mercury lamps, sodium lamps, light emitting diodes (LEDs), semiconductor lasers (LDs), and electroluminescences (ELs) are used as light sources such as exposure apparatuses and static elimination lamps (not shown). General can be used.

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

  Among these light sources, a light emitting diode and a semiconductor laser have high irradiation energy and have a long wavelength light of 600 to 800 [nm], so that they are used favorably.

  The developing device 5 has a developing roller 51 as a developer carrier. A developing bias is applied to the developing roller 51 from a power source (not shown). In the casing of the developing device 5, a supply screw 52 and a stirring screw 53 are provided for stirring the developer contained in the casing while conveying the developer in opposite directions. A doctor 54 for regulating the developer carried on the developing roller 51 is also provided. The toner in the developer stirred and conveyed by the two screws of the supply screw 52 and the stirring screw 53 is charged to a predetermined polarity. The developer is pumped up by the developing roller 51, and the pumped-up developer is regulated by the doctor 54, and the toner adheres to the latent image on the photoconductor 3 in the development area facing the photoconductor 3.

  The cleaning device 6 has a cleaning blade 62. The cleaning blade 62 is in contact with the photoconductor 3 in the counter direction with respect to the surface movement direction of the photoconductor 3. Details of the cleaning blade 62 will be described later.

  The lubricant application device 10 includes a solid lubricant 103, a lubricant pressure spring (not shown), and the like, and uses a fur brush 101 as an application brush for applying the solid lubricant 103 onto the photoreceptor 3. The solid lubricant 103 is held by a bracket (not shown) and is pressed toward the fur brush 101 by a lubricant pressurizing spring (not shown). Then, the solid lubricant 103 is scraped by the fur brush 101 that rotates in the rotational direction with respect to the rotation direction of the photoconductor 3, and the lubricant is applied onto the photoconductor 3. By applying the lubricant to the photoconductor 3, the friction coefficient of the surface of the photoconductor 3 is maintained at 0.2 or less during non-image formation.

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

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

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

  The toner image formed on the photoconductor 3 is supplied to a transfer area formed between the photoconductor 3 and the transfer device 7 from a paper supply unit (not shown) through a facing portion between the upper registration roller and the lower registration roller. It is transferred to the transfer paper to be paper. At this time, the transfer paper is supplied in synchronism with the leading edge of the image at the facing portion between the upper registration roller and the lower registration roller. In addition, a predetermined transfer bias is applied during transfer onto the transfer paper. The transfer paper onto which the toner image has been transferred is separated from the photoreceptor 3 and conveyed to a fixing device (not shown) as a fixing unit. By passing through the fixing device, the toner image is fixed on the transfer paper by the action of heat and pressure, and the transfer paper is discharged out of the apparatus.

  On the other hand, after the transfer, the surface of the photoreceptor 3 is removed by the cleaning device 6 to remove the residual toner. After the lubricant is applied by the lubricant application device 10, the surface of the photoreceptor 3 is discharged by the charge removal lamp.

  Further, in this printer, the photosensitive member 3, the charging device 4, the developing device 5, the cleaning device 6, the lubricant applying device 10 and the like as process means are housed in the frame 2, and the process cartridge 1 is provided from the main body of the apparatus. It is detachable integrally. In the present embodiment, the photosensitive member 3 as the process cartridge 1 and the process means are integrally replaced. However, at least the photosensitive member 3 and the cleaning device 6 are integrally supported, which will be described later. The process cartridge 1 may be configured such that the cleaning blade is in contact with the photosensitive member 3 under a predetermined contact condition.

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

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

  The volume average particle diameter can be determined by a Coulter counter method. Specifically, the toner number distribution and volume distribution data measured by the Coulter Multisizer 2e type (manufactured by Coulter) are sent to a personal computer for analysis via an interface (manufactured by Nikka Kikai). More specifically, a 1% NaCl aqueous solution using first grade sodium chloride is prepared as an electrolytic solution. Then, 0.1 to 5 [ml] of a surfactant, preferably alkylbenzene sulfonate, is added as a dispersant to 100 to 150 [ml] of the electrolytic aqueous solution. Further, 2 to 20 [mg] of toner as a test sample is added thereto, and the dispersion treatment is performed for about 1 to 3 minutes using an ultrasonic disperser. Then, 100 to 200 [ml] of the electrolytic aqueous solution is put into another beaker, and the solution after the dispersion treatment is added to the beaker so as to have a predetermined concentration, and the Coulter Multisizer 2e type is applied.

  The aperture is 100 [μm], and the particle size of 50,000 toner particles is measured. As a channel, it is less than 2.00-2.52 [micrometer]; 2.52-less than 3.17 [micrometer]; 3.17-less than 4.00 [micrometer]; 4.00-5.04 [micrometer] Less than 5.04 to 6.35 [μm]; 6.35 to less than 8.00 [μm]; 8.00 to less than 10.08 [μm]; 10.08 to less than 12.70 [μm]; 12.70 to less than 16.00 [μm]; 16.00 to less than 20.20 [μm]; 20.20 to less than 25.40 [μm]; 25.40 to less than 32.00 [μm]; Using 13 channels of 00 to less than 40.30 [μm], toner particles with a particle size of 2.00 [μm] or more and 32.0 [μm] or less are targeted. Then, the volume average particle diameter is calculated based on the relational expression “volume average particle diameter = ΣXfV / ΣfV”. However, X is the representative diameter in each channel, V is the equivalent volume in the representative diameter of each channel, and f is the number of particles in each channel.

  In such a polymerized toner, as described above, if the pulverized toner is removed from the surface of the photoreceptor 3 in the same manner as when the ground toner is removed from the surface of the photoreceptor 3, the polymerized toner is sufficiently removed from the surface of the photoreceptor 3. Cannot be completely removed, resulting in poor cleaning. Therefore, when the contact pressure of the cleaning blade 92 to the photosensitive member 3 is increased to improve the cleaning performance, there is a problem that the cleaning blade 92 wears out early. Further, the frictional force between the cleaning blade 92 and the photosensitive member 3 is increased, and the ridge line portion (tip ridge line portion) of the cleaning blade 92 in contact with the photosensitive member 3 is pulled in the moving direction of the photosensitive member 3. The tip ridge line turned over. When the tip ridge line portion of the cleaning blade 92 is turned, various problems such as abnormal noise, vibration, and lack of the tip ridge line portion occur.

Therefore, the inventors have intensively studied to solve this problem and have come to achieve the present invention.
That is, an image forming apparatus according to the present invention includes an image carrier, a charging unit that charges the surface of the image carrier, a latent image forming unit that forms an electrostatic latent image on the surface of the charged image carrier, A developing unit that develops the electrostatic latent image formed on the surface of the image carrier to form a toner image; a transfer unit that transfers the toner image on the surface of the image carrier to a transfer member; and a surface that contacts the surface of the image carrier. Cleaning means having a cleaning blade for removing residual toner adhering to the surface of the image carrier, and the cleaning blade has a length in a direction perpendicular to the moving direction of the image carrier. A strip-shaped elastic base material having a width corresponding to, and an end portion in contact with the image carrier of the front end surface of the elastic base material in a region having a predetermined area on the basis of the area of the front end surface Formed and harder than the elastic substrate Is a surface layer of 0.1 to 2 μm, and a cleaning angle that is an angle formed by the tip surface on which the surface layer is formed and the surface of the image carrier is 80 to 85 degrees with respect to the surface of the image carrier The linear pressure is set to 10 to 15 g / cm, and the linear pressure is in contact with the image carrier.

Hereinafter, embodiments of an image forming apparatus according to the present invention will be described.
(First embodiment)
The configuration of the first embodiment of the image forming apparatus according to the present invention will be described with reference to FIGS.
FIG. 3 is a perspective view showing a basic configuration example (1) of the cleaning blade used in the image forming apparatus according to the present invention. 3A is an overall view of the cleaning blade 62, and FIG. 3B is an enlarged view of the elastic blade 622. FIG. 4 is an enlarged cross-sectional view showing the configuration of the first embodiment of the image forming apparatus according to the present invention.

  As shown in FIGS. 3A and 4, the cleaning blade 62 includes a strip-shaped holder 621 made of a rigid material such as metal or hard plastic, and a moving direction of the photosensitive member 3 whose longitudinal direction is a member to be cleaned ( An elastic blade 622 that is a strip-shaped elastic base material that has a length (width) direction perpendicular to the rotation direction) and that corresponds to the width of the photoconductor 3, and a photoconductor of the elastic blade 622. 3 at a predetermined film thickness on each of a front end surface 62a constituting a front end ridge line portion (also referred to as a front end corner portion) 62c and a blade lower surface 62b which is a main surface facing the photoreceptor 3. And a surface layer 623 that is formed and harder than the elastic blade 622. The elastic blade 622 is fixed to one end side of the holder 621 with an adhesive or the like, and the other end side of the holder 621 is cantilevered by the case of the cleaning device 6.

  Here, the elastic blade 622 is preferably a rubber having a high resilience elastic modulus so that the elastic blade 622 can follow the eccentricity of the photosensitive member 3 and the minute undulations on the surface of the photosensitive member 3. Certain urethane rubbers are preferred.

The hardness of the elastic blade 622 is preferably urethane rubber having a hardness at 25 ° C. of 69 to 75 degrees (JIS A). When the hardness of the urethane rubber exceeds 75 degrees, the flexibility becomes poor. For example, when the holder 621 is slightly tilted and attached to the cleaning device 6, the axial direction (width direction) one end side of the cleaning blade 62 and It is easy to make a so-called uneven contact with different contact pressures on the other end side, making it difficult to obtain a uniform contact pressure in the axial direction. As a result, there is a possibility that the cleaning property is deteriorated.
On the other hand, when the hardness is less than 69 degrees, the cleaning blade 62 is warped when the contact pressure is set high so that even the polymerized toner can be cleaned, and the leading edge line portion 62c of the cleaning blade 62 is lifted, and the cleaning blade A so-called anti-hit phenomenon occurs in which the blade lower surface 62b of 62 is in contact with the photosensitive member 3. When the stomach contact phenomenon occurs, the contact area between the cleaning blade 62 and the surface of the photosensitive member 3 increases abruptly. Therefore, even if the cleaning blade 62 is pressed with a large force, the contact pressure is reduced and the cleaning performance is lowered. This is not suitable. In particular, in the configuration having the surface layer 623 on the tip surface 62a of the elastic blade 622 as in the present invention, these phenomena occur remarkably, so the hardness of the elastic blade 622 needs to be in the above range.

  The surface layer 623 is a film made of a material having a hardness higher than that of the elastic blade 622 formed so as to cover the leading edge portion 62c of the cleaning blade 62 by spray coating, dip coating, screen printing, or the like. Accordingly, the surface layer 623 is made of a member having a hardness higher than that of the elastic blade 622 and is rigid, so that the surface layer 623 is difficult to be deformed, and the turning of the leading edge portion 62c of the cleaning blade 62 can be suppressed.

  The material of the surface layer 623 is preferably a resin, and more preferably an ultraviolet curable resin. By using the ultraviolet curable resin, the surface layer 623 having a desired hardness harder than that of the elastic blade 622 can be obtained simply by irradiating the resin adhering to the tip ridge line portion 62c of the cleaning blade 62 with ultraviolet rays. The blade 62 can be manufactured at low cost.

  As the ultraviolet curable resin used for forming the surface layer 623, it is preferable to use a monomer having a molecular weight of 300 to 1500 per functional group. When the molecular weight per functional group exceeds 1500, the surface layer 623 becomes too fragile, the tip edge line portion 62c of the cleaning blade 62 turns over, and the tip surface wear as shown in FIG. The cleaning property cannot be maintained. On the other hand, when the molecular weight is less than 300, the surface layer 623 becomes too rigid. If the surface layer 623 becomes too rigid, the wear resistance performance of the surface layer 623 is reduced and chatter noise (abnormal noise) is likely to occur.

  The layer thickness (film thickness) of the surface layer 623 is preferably 0.1 to 2 [μm]. This layer thickness is the thickness on the plane of the tip surface 62a or the blade lower surface 62b excluding the tip ridge line portion 62c of the elastic blade 622, which is at least 50 times the layer thickness from the viewpoint of uniformity. The value at a location far from the front end ridge line portion 62c is used. If the layer thickness is less than 0.1 [μm], the rigidity of the surface layer 623 becomes weak, and the leading edge portion 62c of the cleaning blade 62 is likely to be turned. On the other hand, when the layer thickness exceeds 2 [μm], the rigidity of the tip ridge line portion 62c of the cleaning blade 62 increases, and the toner slip-through increases due to the decrease in the followability to the surface shape change of the photoreceptor 3. It becomes easy to generate defective cleaning. Furthermore, when the layer thickness exceeds 2 [μm], the corner angle of the tip ridge line portion 62c of the cleaning blade 62 becomes obtuse. That is, when the surface layer 623 is formed by adhering a liquid material as in spray coating or dip coating, the tip ridge line portion 62c is difficult to form a coating film due to the surface tension, and the tip ridge line portion This is because the thickness of the surface layer 623 tends to increase as the distance from 62c increases. As a result, the corner angle of the tip ridge line portion 62c of the cleaning blade 62 becomes an obtuse angle, and the tip surface 62a on which the surface layer 623 is formed and the photoreceptor 3 are compared with the case where the corner angle of the tip ridge line portion 62c is a right angle. The gap X (see FIG. 4) on the upstream side of the contact portion formed becomes narrow. In this case, when the cleaning operation is performed for a long period of time, toner accumulates in the gap X, and the toner in the blocked gap X disappears, and the toner in the gap X is gradually pushed out to the downstream side of the photoreceptor 3. Inadequate cleaning will occur.

  In the present embodiment, as shown in FIG. 3B, the surface layer 623 is formed on a part of the tip surface 62a and a part of the blade lower surface 62b so as to straddle the tip ridge line part 62c. Reinforced moderately. That is, the tip surface 62a has a region where the surface layer 623 is not formed (non-covered region), and instead, the surface layer 623 is formed on a part of the blade lower surface 62b.

  Here, the area of the region covered by the surface layer 623 is preferably 1.00 times or more and 2.50 times or less, and 1.00 times the area of the tip surface 62a (width of the elastic blade 622 × thickness t). Above, 1.50 times or less is more preferable. At this time, since the surface layer 623 covers the entire width of each of the tip surface 62a and the blade lower surface 62b, the elasticity of the region covered with the surface layer 623 on the tip surface 62a as shown in FIG. The length in the thickness direction of the body blade 622 (distance from the leading edge portion 62c) L1 and the length in the direction perpendicular to the width direction of the elastic blade 622 in the region covered with the surface layer 623 on the blade lower surface 62b ( The sum of the distance L2 from the tip ridge line portion 62c) is preferably 1.00 times or more and 2.50 times or less, more preferably 1.00 times or more and 1.50 times or less the thickness t of the elastic blade 622. It can be said.

  Further, the surface layer 623 is preferably formed in a region that is substantially half of the total length (thickness t) in the thickness direction of the elastic blade 622 on the tip end surface 62a. The area of the surface layer 623 formed on the blade lower surface 62b is preferably substantially the same as the area of the surface layer 623 formed on the tip surface 62a.

  Further, the method of bringing the leading edge portion 62c into contact with the photosensitive member 3 includes the case of the elastic blade 622 that does not form the surface layer 623 and the case of the elastic blade 622 that forms the surface layer 623 as in the present invention. The contact condition differs depending on the case. That is, in the case of the elastic blade 622 that does not form the surface layer 623, the cleaning angle, which is the angle formed by the tip surface 62a and the surface of the photosensitive member 3, is 75 to 80 degrees, and the linear pressure on the photosensitive member 3 is 20 to 25 g / cm. As described above, the elastic blade 622 is relatively strongly pressed against the photosensitive member 3 to bend the elastic blade 622 so as to contact the surface of the photosensitive member 3. On the other hand, in the present invention, the cleaning angle, which is the angle formed by the tip surface 62a on which the surface layer 623 is formed, and the photoreceptor 3 is 80 to 85 degrees, and the linear pressure on the surface of the photoreceptor 3 is 10 to 15 g / cm. The elastic blade 622 is pressed against and contacted with the photoreceptor 3 under relatively light conditions (FIG. 4).

  When the cleaning blade 62 having the above configuration is used, the elastic body blade 622 has an appropriate rigidity by forming the surface layer 623 on a part of the tip surface 62a and a part of the blade lower surface 62b across the tip ridge line part 62c. Since flexibility can be imparted, when the cleaning blade 62 is brought into contact with the photosensitive member 3, the contact portion (tip ridge line portion 62 c) moves in the moving direction of the photosensitive member 3. This prevents the wear and tear, prevents filming on the photosensitive member 3, and prevents the generation of abnormal noise. Further, since the contact portion (tip ridge line portion 62c) of the elastic body blade 622 follows the surface shape change of the photoconductor 3, the tip ridge line portion 62c, that is, the surface layer 623 always has a predetermined pressure over the entire width of the photoconductor 3. Therefore, good cleaning properties can be maintained for a long time without damaging the surface of the photoreceptor 3.

(Second Embodiment)
The configuration of the second embodiment of the image forming apparatus according to the present invention will be described with reference to FIGS.
FIG. 5 is a perspective view showing a basic configuration example (2) of the cleaning blade used in the image forming apparatus according to the present invention. FIG. 5A is an overall view of the cleaning blade 62, and FIG. 5B is an enlarged view of the elastic blade 622. FIG. 6 is an enlarged sectional view showing the configuration of the second embodiment of the image forming apparatus according to the present invention. In addition, the material which comprises the cleaning blade 62 in this embodiment is the same as 1st Embodiment, and the covering state of the surface layer 623 differs from the thing of 1st Embodiment, and others are 1st Embodiment. Same as shown.

  That is, the surface layer 623 is formed only on the entire front end surface 62a of the elastic blade 622, as shown in FIG. That is, in this embodiment, the surface layer 623 is not formed on the blade lower surface 62b.

  Further, the contact condition of the leading edge portion 62c with the photosensitive member 3 is a cleaning angle of 80 to 80, which is an angle formed by the leading edge surface 62a on which the surface layer 623 is formed and the photosensitive member 3, as in the first embodiment. The elastic blade 622 is pressed against and brought into contact with the photosensitive member 3 under a relatively light condition at 85 degrees and the linear pressure on the surface of the photosensitive member 3 is set to 10 to 15 g / cm (FIG. 6).

  If the cleaning blade 62 having the above configuration is used, the surface blade 623 is formed only on the entire front end surface 62a, so that appropriate rigidity and flexibility can be imparted to the elastic blade 622. When contacted with the photoreceptor 3, the contact portion (tip ridge line portion 62 c) is prevented from moving in the moving direction of the photoreceptor 3 to suppress the erosion wear and fill the photoreceptor 3. This prevents the generation of abnormal noise. Further, since the contact portion (tip ridge line portion 62c) of the elastic body blade 622 follows the surface shape change of the photoconductor 3, the tip ridge line portion 62c, that is, the surface layer 623 always has a predetermined pressure over the entire width of the photoconductor 3. Therefore, good cleaning properties can be maintained for a long time without damaging the surface of the photoreceptor 3.

Hereinafter, the verification experiment of the present invention conducted by the inventors will be described.
[Example A]
In the first embodiment of the present invention, the cleaning blade 62 (FIGS. 3 and 4) was produced by changing the conditions of the elastic blade 622 and the surface layer 622, and the durability test was performed.
[Sample material]
The conditions of the elastic blade 622 and the surface layer 623 are as follows.
(1) Elastic body blade 622
As the elastic body blade 622, five urethane rubbers (urethane rubber Nos. A1 to A5) having the following physical properties at 25 [° C.] were used.
Urethane rubber A1: Hardness 74 degrees, rebound resilience 49 [%] (manufactured by Toyo Tire & Rubber)
Urethane rubber A2: hardness 69 degrees, rebound resilience 50 [%] (manufactured by Toyo Tire & Rubber)
Urethane rubber A3: hardness 72 degrees, rebound resilience 31 [%] (manufactured by Toyo Tire & Rubber)
Urethane rubber A4: Hardness 71 degrees, rebound resilience 18 [%] (manufactured by Toyo Tire & Rubber)
Urethane rubber A5: hardness 72 degrees, rebound resilience 23 [%] (manufactured by Syndtech)

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

(2) Surface layer 623
As the surface layer 623, the following five ultraviolet curable resin films (surface layers No. 1 to 5) were used.
(Surface layer 1)
Urethane acrylate oligomer 1: Negami Kogyo UN-904 0.5 part Urethane acrylate oligomer 2: Negami Kogyo UN-2700 19.5 parts Polymerization initiator: Ciba Specialty Chemicals Irgacure 184 1 part Solvent: 2-butanone 79 parts Coating film Hardness: Pencil hardness 2H
Friction coefficient: 0.6
(Surface layer 2)
Urethane acrylate oligomer 1: Negami Kogyo UN-904 5 parts Urethane acrylate oligomer 2: Negami Kogyo UN-2700 15 parts Polymerization initiator: Ciba Specialty Chemicals Irgacure 184 1 part Solvent: 2-butanone 79 parts Coating film hardness: Pencil hardness 3H
Friction coefficient: 0.5
(Surface layer 3)
Urethane acrylate oligomer 1: Negami Kogyo UN-904 8 parts Urethane acrylate oligomer 2: Negami Kogyo UN-2700 12 parts Polymerization initiator: Ciba Specialty Chemicals Irgacure 184 1 part Solvent: 2-butanone 79 parts Coating film hardness: Pencil hardness 6H
Friction coefficient: 0.45
(Surface layer 4)
Urethane acrylate oligomer 1: Negami Kogyo UN-3320HA 5 parts Urethane acrylate oligomer 2: Negami Kogyo UN-2700 15 parts Polymerization initiator: Ciba Specialty Chemicals Irgacure 184 1 part Solvent: 2-butanone 79 parts Coating film hardness: Pencil hardness 2H
Friction coefficient: 0.5
(Surface layer 5)
Urethane acrylate oligomer 1: Negami Kogyo UN-904 20 parts Polymerization initiator: Ciba Specialty Chemicals Irgacure 184 1 part Solvent: 2-butanone 79 parts Coating film hardness: pencil hardness 9H
Friction coefficient: 0.4

The pencil hardness of the surface layer 623 was measured according to JIS K5600-5-4 using a pencil scratch tester KTVF-2380 manufactured by Cortec Corporation. The sample was obtained by spraying the material of the surface layer 623 on a glass plate of 50 [mm] × 50 [mm] by about 5 [μm].
In addition, the friction coefficient of the surface layer 623 is measured using the Shinto Kagaku Tribogear Muse 94i and the maximum static friction coefficient for the cloth material (standard product for Tribogear Muse 94i, test cloth for clock meter made by Atlas Electric Device Co., Ltd.). did. The sample was obtained by spraying the coating material on a glass plate of 50 [mm] × 50 [mm] by about 5 [μm].

[Experimental procedure]
Next, the procedure of the verification experiment will be described.
First, a strip-shaped elastic blade 622 having a thickness (t) of 1.8 mm is prepared using any of the urethane rubbers A1 to A5, and as shown in FIG. Any one of the surface layers 1 to 5 was formed on a part of each of the leading end surface 62a and the blade lower surface 62b by spray coating. Specifically, first, the tip surface 62a of the elastic blade 622 is overcoated so as to have a predetermined film thickness at a spray gun moving speed of 10 [mm / s], and touch-dried for 3 minutes. Next, coating was performed so that a surface layer was similarly formed on the blade lower surface 62b. Thereafter, finger touch drying was further performed for 3 minutes, and ultraviolet exposure (140 [W / cm] × 5 [m / min] × 5 passes) was performed. In addition, the area | region which forms a surface layer by spray coating at this time was restrict | limited with the masking tape, and it applied.
Next, the obtained elastic blade 622 was fixed with an adhesive to a sheet metal holder (holder 621) that can be mounted on the Ricoh color composite machine imagio MP C4500, and a prototype cleaning blade 62 was obtained.

  This was similarly attached to a Ricoh color composite machine imagio MP C4500 (same configuration as FIG. 1), and image forming apparatuses of Examples A1 to A5 and Comparative Examples A1 to A3 were produced. The cleaning blade 62 was attached so as to have a predetermined linear pressure and cleaning angle according to the tip biting amount and attachment angle examined in advance.

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

[Evaluation item]
The verification experiment was conducted in a laboratory environment: 21 [° C.] 65 [% RH], paper feeding condition: image area ratio 5% chart with 3 prints / job, passing 50000 sheets (copy paper A4 side). It was.
The evaluation items are as follows.

(1) Blade edge wear width: The wear width on the blade lower surface 62b side was measured as shown in FIG.
(2) Occurrence of cleaning failure: The following evaluation image was formed after continuous feeding of 50000 sheets, and the presence or absence of cleaning failure was visually observed.
Image at the time of evaluation: Vertical band pattern (with respect to the paper traveling direction) 43 [mm] width, 3 charts
Output 20 sheets (copier paper A4 side)
(3) Abnormal noise generation: Presence / absence (4) Excavation wear of blade tip surface 62a: Presence / absence (visual observation)

The conditions and results of the verification experiments for the cleaning blades of Examples A1 to A5 and Comparative Examples A1 to A3 are shown below.
In addition, the film thickness of the surface layer 623 was measured with the cross section of the elastic body blade 622 separately applied similarly using the Keyence microscope VHX-100. The sample used was a cross-section cut using a trimming razor for Nisshin EM electron microscope (SEM) sample preparation.

(Example A1)
Elastic blade 622: Urethane rubber A2
-Surface layer 623: Surface layer 3
..Formation length L1: 1.0 [mm] on the tip surface 62a
..Layer thickness at tip surface 62a: 1.0 [μm]
..Formation length L2 on the blade lower surface 62b: 1.0 [mm]
..Layer thickness on blade lower surface 62b: 1.0 [μm]
..Area ratio with respect to the tip end face 62a area ((L1 + L2) / t): 1.11.
・ Cleaning blade contact condition ・ ・ Cleaning angle: 80 degrees
..Line pressure: 12 [g / cm]
・ Blade edge wear width: 4.0 [μm]
・ Cleaning failure occurrence: None ・ Noise occurrence: None

(Example A2)
Elastic blade 622: Urethane rubber A5
-Surface layer 623: Surface layer 1
..Formation length L1 at the front end face 62a: 0.9 [mm]
..Layer thickness at tip surface 62a: 0.5 [μm]
..Formation length L2 on the blade lower surface 62b: 1.0 [mm]
..Layer thickness on blade lower surface 62b: 0.5 [μm]
..Area ratio with respect to the tip end face 62a area ((L1 + L2) / t): 1.06
・ Cleaning blade contact condition ・ ・ Cleaning angle: 85 degrees
..Line pressure: 13 [g / cm]
・ Blade edge wear width: 5.0 [μm]
・ Cleaning failure occurrence: None ・ Noise occurrence: None

(Example A3)
Elastic blade 622: Urethane rubber A1
-Surface layer 623: Surface layer 5
..Formation length L1: 1.1 [mm] on the tip surface 62a
..Layer thickness at tip surface 62a: 1.5 [μm]
..Formation length L2 on the blade lower surface 62b: 1.5 [mm]
..Layer thickness on blade lower surface 62b: 0.7 [μm]
..Area ratio with respect to the tip end face 62a area ((L1 + L2) / t): 1.44
・ Cleaning blade contact condition ・ ・ Cleaning angle: 82 [degrees]
..Line pressure: 15 [g / cm]
・ Blade edge wear width: 6.0 [μm]
・ Cleaning failure occurrence: None ・ Noise occurrence: None

(Example A4)
Elastic blade 622: Urethane rubber A4
-Surface layer 623: Surface layer 2
..Formation length L1: 1.0 [mm] on the tip surface 62a
..Layer thickness at tip surface 62a: 0.8 [μm]
..Formation length L2 on the blade lower surface 62b: 1.2 [mm]
..Layer thickness on blade lower surface 62b: 0.6 [μm]
..Area ratio with respect to the tip end face 62a area ((L1 + L2) / t): 1.22
・ Cleaning blade contact condition ・ ・ Cleaning angle: 80 degrees
..Line pressure: 12 [g / cm]
・ Blade edge wear width: 4.5 [μm]
・ Cleaning failure occurrence: None ・ Noise occurrence: None

(Example A5)
Elastic blade 622: Urethane rubber A3
-Surface layer 623: Surface layer 4
..Formation length L1 at the front end face 62a: 0.9 [mm]
..Layer thickness at tip surface 62a: 0.5 [μm]
..Formation length L2 on the blade lower surface 62b: 1.0 [mm]
..Layer thickness on blade lower surface 62b: 0.5 [μm]
..Area ratio with respect to the tip end face 62a area ((L1 + L2) / t): 1.06
・ Cleaning blade contact condition ・ ・ Cleaning angle: 82 [degrees]
..Line pressure: 10 [g / cm]
・ Blade edge wear width: 3.5 [μm]
・ Cleaning failure occurrence: None ・ Noise occurrence: None

(Comparative Example A1)
Elastic blade 622: Urethane rubber A4
-Surface layer 623: Surface layer 2
..Formation length L1: 1.8 [mm] on the front end surface 62a (entire surface)
..Layer thickness at tip surface 62a: 2.0 [μm]
..Formation length L2 on the blade lower surface 62b: 10.0 [mm]
..Layer thickness on blade lower surface 62b: 2.5 [μm]
.. Area ratio to tip surface 62a area ((L1 + L2) / t): 6.56
・ Cleaning blade contact condition ・ ・ Cleaning angle: 80 degrees
..Line pressure: 15 [g / cm]
・ Blade edge wear width: 12.5 [μm]
・ Cleaning failure occurred: Two belt-like cleaning defects ・ Abnormal noise occurrence: chattering

(Comparative Example A2)
Elastic blade 622: Urethane rubber A1
-Surface layer 623: Surface layer 1
..Formation length L1: 1.8 [mm] on the front end surface 62a (entire surface)
..Layer thickness at tip surface 62a: 5.0 [μm]
..Formation length L2 on the blade lower surface 62b: 3.0 [mm]
..Layer thickness on blade lower surface 62b: 5.0 [μm]
.. Area ratio to tip surface 62a area ((L1 + L2) / t): 2.67
・ Cleaning blade contact condition ・ ・ Cleaning angle: 79 degrees
..Line pressure: 20 [g / cm]
・ Blade edge wear width: 15.0 [μm]
・ Cleaning failure occurrence: 4 streaky cleaning failures ・ Abnormal noise occurrence: chattering ・ Gap wear at the tip

(Comparative Example A3)
Elastic blade 622: Urethane rubber A2
-Surface layer 623: Surface layer 3
..Formation length L1 at the front end face 62a: 1.7 [mm]
..Layer thickness at tip surface 62a: 8.0 [μm]
..Formation length L2 on the blade lower surface 62b: 5.0 [mm]
..Layer thickness on blade lower surface 62b: 10.0 [μm]
.. Area ratio with respect to tip surface 62a area ((L1 + L2) / t): 3.72
・ Cleaning blade contact condition ・ ・ Cleaning angle: 77 degrees
..Line pressure: 22 [g / cm]
・ Blade edge wear width: 9.0 [μm]
・ Insufficient cleaning: 3 belt-like cleaning defects ・ Abnormal noise: chattering ・ Gripping tip wear

Table 1 summarizes the results of verification experiments of Examples A1 to A5 and Comparative Examples A1 to A3.
In each of Examples A1 to A5, it was possible to suppress blade edge wear over time and maintain good cleaning properties, and it was also possible to suppress erosion wear on the tip surface 62a of the cleaning blade 62 and generation of abnormal noise. .
On the other hand, in Comparative Examples A1 to A3, even when the same contact condition was adopted, filming on the surface of the image carrier, generation of abnormal noise, and further increase in wear occurred over time. For example, when the area ratio of the surface layer 623 exceeds a predetermined range, it is considered that filming on the surface of the photoconductor 3 and generation of abnormal noise may occur over time. Further, if the thickness of the surface layer 623 on the tip surface 62a and the blade lower surface 62b is not within a predetermined range, blade wear may increase or abnormal noise may occur, and it is considered that good cleaning properties cannot be maintained. .
From the above, the surface layer 623 is locally formed on the blade tip under a predetermined condition, and the contact condition is limited to a specific condition. It is considered that filming on the photosensitive member 3 and generation of abnormal noise on the blade itself can be suppressed.

[Example B]
In the second embodiment of the present invention, the cleaning blade 62 (FIGS. 5 and 6) was prepared by changing the conditions of the elastic blade 622 and the surface layer 623, and the durability test was performed.

[Sample material]
The conditions of the elastic blade 622 and the surface layer 623 are as follows.
(1) Elastic body blade 622
As the elastic blade 622, five urethane rubbers (urethane rubber Nos. B1 to B4) having the following physical properties at 25 [° C.] were used.
Urethane rubber B1: Hardness 69 degrees, rebound resilience 50 [%] (manufactured by Toyo Tire & Rubber)
Urethane rubber B2: Hardness 72 degrees, rebound resilience 31 [%] (manufactured by Toyo Tire & Rubber)
Urethane rubber B3: Hardness 75 degrees, rebound resilience 45 [%] (manufactured by Toyo Tire & Rubber)
Urethane rubber B4: Hardness 76 degrees, rebound resilience 32 [%] (manufactured by Syndtech)

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

(2) Surface layer 623
As the surface layer 623, the same five ultraviolet curable resin films (surface layers No. 1 to 5) as in Example A were used.

[Experimental procedure]
Next, the procedure of the verification experiment will be described.
First, by using any of the urethane rubbers B1 to B4, a strip-shaped elastic blade 622 having a thickness (t) of 1.8 mm is formed, and as shown in FIG. Only the surface layers 1 to 5 were formed by spray coating only. Specifically, first, the tip surface 62a of the elastic blade 622 was overcoated at a spray gun moving speed of 10 [mm / s] so as to have a predetermined film thickness, and then touch-dried for 3 minutes. Note that some of the comparative samples were coated so that the surface layer was similarly formed on the blade lower surface 62b, and then touch-dried for another 3 minutes. Then, ultraviolet exposure (140 [W / cm] × 5 [m / min] × 5 passes) was performed. In addition, the area | region which forms a surface layer by spray coating at this time was restrict | limited with the masking tape, and it applied.
Next, the obtained elastic blade 622 was fixed with an adhesive to a sheet metal holder (holder 621) that can be mounted on the Ricoh color composite machine imagio MP C4500, and a prototype cleaning blade 62 was obtained.

  This was similarly attached to a Ricoh color composite machine imagio MP C4500 (same configuration as in FIG. 1), and image forming apparatuses of Examples B1 to B5 and Comparative Examples B1 to B5 were produced. The cleaning blade 62 was attached so as to have a predetermined linear pressure and cleaning angle according to the tip biting amount and attachment angle examined in advance.

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

[Evaluation item]
The verification experiment was conducted in a laboratory environment: 21 [° C.] 65 [% RH], paper feeding condition: image area ratio 5% chart with 3 prints / job, passing 50000 sheets (copy paper A4 side). It was.
The evaluation items are as follows.

(1) Blade edge wear width: The wear width on the blade lower surface 62b side was measured as shown in FIG.
(2) Occurrence of cleaning failure: The following evaluation image was formed after continuous feeding of 50000 sheets, and the presence or absence of cleaning failure was visually observed.
Image at the time of evaluation: Vertical band pattern (with respect to the paper traveling direction) 43 [mm] width, 3 charts
Output 20 sheets (copier paper A4 side)
(3) Abnormal noise generation: Presence / absence (4) Excavation wear of blade tip surface 62a: Presence / absence (visual observation)

The conditions and results of the verification experiments for the cleaning blades of Examples B1 to B5 and Comparative Examples B1 to B5 are shown below.
In addition, the film thickness of the surface layer 623 was measured with the cross section of the elastic body blade 622 separately applied similarly using the Keyence microscope VHX-100. The sample used was a cross-section cut using a trimming razor for Nisshin EM electron microscope (SEM) sample preparation.

(Example B1)
Elastic blade 622: Urethane rubber B1
Surface layer 623: Surface layer 5 (layer thickness 0.1 [μm])
・ Cleaning blade contact condition ・ ・ Cleaning angle: 82 [degrees]
..Line pressure: 15 [g / cm]
・ Blade edge wear width: 3.0 [μm]
・ Cleaning failure occurrence: None ・ Noise occurrence: None

(Example B2)
Elastic blade 622: Urethane rubber B3
Surface layer 623: Surface layer 3 (layer thickness 0.5 [μm])
・ Cleaning blade contact condition ・ ・ Cleaning angle: 80 degrees
..Line pressure: 10 [g / cm]
・ Blade edge wear width: 5.0 [μm]
・ Cleaning failure occurrence: None ・ Noise occurrence: None

(Example B3)
Elastic blade 622: Urethane rubber B2
Surface layer 623: Surface layer 1 (layer thickness 2.0 [μm])
・ Cleaning blade contact condition ・ ・ Cleaning angle: 85 degrees
..Line pressure: 13 [g / cm]
・ Blade edge wear width: 7.0 [μm]
・ Cleaning failure occurrence: None ・ Noise occurrence: None

(Example B4)
Elastic blade 622: Urethane rubber B1
Surface layer 623: Surface layer 2 (layer thickness 1.0 [μm])
・ Cleaning blade contact condition ・ ・ Cleaning angle: 82 [degrees]
..Line pressure: 15 [g / cm]
・ Blade edge wear width: 10.0 [μm]
・ Cleaning failure occurrence: None ・ Noise occurrence: None

(Example B5)
Elastic blade 622: Urethane rubber B2
Surface layer 623: Surface layer 4 (layer thickness 1.0 [μm])
・ Cleaning blade contact condition ・ ・ Cleaning angle: 80 degrees
..Line pressure: 12 [g / cm]
・ Blade edge wear width: 6.0 [μm]
・ Cleaning failure occurrence: None ・ Noise occurrence: None

(Comparative Example B1)
Elastic blade 622: Urethane rubber B1
-Surface layer 623: Surface layer 5
..Formation length L1: 1.8 [mm] on the front end surface 62a (entire surface)
..Layer thickness at tip surface 62a: 1.0 [μm]
..Formation length L2 on the blade lower surface 62b: 10.0 [mm]
..Layer thickness on blade lower surface 62b: 1.0 [μm]
..Area ratio with respect to the area of the front end face 62a ((L1 + L2) / t): 11.8
・ Cleaning blade contact condition ・ ・ Cleaning angle: 80 degrees
..Line pressure: 15 [g / cm]
・ Blade edge wear width: 12.0 [μm]
・ Cleaning failure occurred: 3 streaky cleaning defects ・ Abnormal noise: chatter

(Comparative Example B2)
Elastic blade 622: Urethane rubber B4
Surface layer 623: Surface layer 3 (layer thickness 5.0 [μm])
・ Cleaning blade contact condition ・ ・ Cleaning angle: 80 degrees
..Line pressure: 13 [g / cm]
・ Blade edge wear width: 20.0 [μm]
・ Cleaning failure occurrence: strip cleaning failure 3 places ・ Noise generation: chattering

(Comparative Example B3)
Elastic blade 622: Urethane rubber B2
-Surface layer 623: None-Cleaning blade contact conditions-Cleaning angle: 78 [degrees]
..Line pressure: 18 [g / cm]
・ Blade edge wear width: 9.0 [μm]
・ Cleaning failure occurred: 2 belt-like cleaning failures ・ Noise generation: None

(Comparative Example B4)
Elastic blade 622: Urethane rubber B2
Surface layer 623: Surface layer 1 (layer thickness 2.0 [μm])
・ Cleaning blade contact condition ・ ・ Cleaning angle: 86 degrees
..Line pressure: 16 [g / cm]
・ Blade edge wear width: 12.0 [μm]
・ Cleaning failure occurred: Two belt-like cleaning failures ・ Noise generation: None

(Comparative Example B5)
Elastic blade 622: Urethane rubber B1
Surface layer 623: Surface layer 2 (layer thickness 1.0 [μm])
・ Cleaning blade contact condition ・ ・ Cleaning angle: 79 degrees
..Line pressure: 9 [g / cm]
・ Blade edge wear width: 15.0 [μm]
・ Cleaning failure occurred: 2 streaky cleaning defects ・ Abnormal noise occurrence: None

Table 2 summarizes the results of verification experiments of Examples B1 to B5 and Comparative Examples B1 to B5.
In each of Examples B1 to B5, it was possible to suppress blade edge wear over time and maintain good cleaning properties, and it was also possible to suppress erosion wear on the tip surface 62a of the cleaning blade 62 and generation of abnormal noise. .
On the other hand, in the comparative example, even when the same contact condition is employed, if a surface layer is provided in addition to the front end face 62a (Comparative Example B1) or a specific elastic blade is used (Comparative Example B2), the photosensitive member 3 over time. This resulted in filming on the surface, generation of abnormal noise, and increased wear. Further, in the combination of the surface layer 623 and the elastic body blade 622, as the contact condition, if the linear pressure exceeds 15 [g / cm] and the cleaning angle is less than 80 [degrees], the filming on the surface of the photoreceptor 3 over time can be performed. Increased wear was observed.
Further, when the thickness of the surface layer 623 is not in the range of 0.1 [μm] to 2 [μm], blade wear may increase and abnormal noise may occur, and good cleaning properties can be maintained. could not.
From the above, when the surface layer 623 is formed only on the entire front end surface 62a, the elastic blade 622 is specified and the surface layer 623 is set to an appropriate layer thickness, and the contact condition is limited to the specified condition. By doing so, it is considered that the movability of the blade tip does not deteriorate, good cleaning performance can be maintained, and filming on the photoreceptor 3 and generation of abnormal noise of the blade itself can be suppressed.

  Although the present invention has been described with the embodiments shown in the drawings, the present invention is not limited to the embodiments shown in the drawings, and other embodiments, additions, modifications, deletions, etc. Can be changed within the range that can be conceived, and any embodiment is included in the scope of the present invention as long as the effects and advantages of the present invention are exhibited.

DESCRIPTION OF SYMBOLS 1 Process cartridge 2 Frame 3 Photoconductor 4 Charging device 5 Developing device 6 Cleaning device 7 Transfer device 10 Lubricant application device 14 Transfer belt 51 Developing roller 52 Supply screw 53 Stirring screw 54 Doctor 62, 92 Cleaning blade 62a, 92a Tip surface 62b, 92c Blade lower surface 62c, 92c Tip edge portion 101 Fur brush 103 Solid lubricant 621 Holder 622 Elastic blade 623 Surface layer L Light

Japanese Patent No. 3602898 JP 2004-233818 A

Claims (7)

An image carrier, a charging unit for charging the surface of the image carrier, a latent image forming unit for forming an electrostatic latent image on the charged image carrier surface, and an electrostatic latent image formed on the surface of the image carrier. Developing means for developing the image into a toner image; Transfer means for transferring the toner image on the surface of the image carrier to the transfer body; and Residual toner attached to the surface of the image carrier in contact with the surface of the image carrier In an image forming apparatus comprising a cleaning means having a cleaning blade for removing
The cleaning blade is
A strip-shaped elastic substrate having a width corresponding to the length in a direction perpendicular to the moving direction of the image carrier;
It is formed in a region of a predetermined area including the end of the tip surface of the elastic base material in contact with the image carrier and is harder than the elastic base material and has a layer thickness. A surface layer of 0.1 to 2 μm,
The image carrier is set with a cleaning angle of 80 to 85 degrees, which is an angle formed between the tip surface on which the surface layer is formed and the surface of the image carrier, and a linear pressure with respect to the surface of the image carrier is 10 to 15 g / cm. An image forming apparatus which is in contact with a body.   The surface layer includes one of a tip surface constituting a tip ridge line portion on an end portion side of the elastic substrate that contacts the image carrier and a lower surface of a blade that is a main surface facing the image carrier. The image forming apparatus according to claim 1, wherein the image forming apparatus is formed in a portion.   3. The image forming apparatus according to claim 2, wherein the surface layer is formed in a region that is substantially half of a total length of the elastic base material in the thickness direction on the front end surface.   The image forming apparatus according to claim 2, wherein an area of the surface layer formed on the lower surface of the blade is substantially the same as an area of the surface layer formed on the tip surface.   The image forming apparatus according to claim 1, wherein the surface layer is formed only on the entire front end surface of the elastic base material.   The image forming apparatus according to claim 1, wherein the elastic base material is made of rubber containing a urethane group. An image carrier, a charging unit for charging the surface of the image carrier, a latent image forming unit for forming an electrostatic latent image on the charged image carrier surface, and an electrostatic latent image formed on the surface of the image carrier. Developing means for developing the image into a toner image; Transfer means for transferring the toner image on the surface of the image carrier to the transfer body; and Residual toner attached to the surface of the image carrier in contact with the surface of the image carrier In a process cartridge that can be attached to and detached from an image forming apparatus including a cleaning blade that removes the image carrier, and integrally supports the image carrier and the cleaning means.
The cleaning blade is
A strip-shaped elastic substrate having a width corresponding to the length in a direction perpendicular to the moving direction of the image carrier;
It is formed in a region of a predetermined area including the end of the tip surface of the elastic base material in contact with the image carrier and is harder than the elastic base material and has a layer thickness. A surface layer of 0.1 to 2 μm,
The image carrier is set with a cleaning angle of 80 to 85 degrees, which is an angle formed between the tip surface on which the surface layer is formed and the surface of the image carrier, and a linear pressure with respect to the surface of the image carrier is 10 to 15 g / cm. A process cartridge which is in contact with a body.

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