JP2011197218A - Cleaning blade, image forming apparatus, and process cartridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cleaning blade using a blade consisting of a metal member, which allows followability to fluctuation of eccentricity of an image carrier and minute swell of the surface or the like, and which achieves successful cleaning performance and lengthening of a usable period.SOLUTION: A metal blade 622 consisting of the metal member is used for the cleaning blade 62 which removes powder from the surface of a photoreceptor 3, the shape is formed like a strip so as to have flexibility, and its ridgeline part 62c is covered with a surface layer consisting of ultraviolet curing resin or thermosetting resin.

Description

  The present invention relates to a cleaning blade provided in a cleaning device used in an electrophotographic image forming apparatus, an image forming apparatus including the 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 not detected on an image carrier such as a photosensitive member which is a member to be cleaned. It is removed by a cleaning device which is a cleaning means. 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, the tip ridge line 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 referred to as a polymerization toner) formed by a polymerization method or the like is known. This polymerized toner has features such as higher transfer efficiency than conventional pulverized toner, and can meet the above-described 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 polymer toner having a small particle diameter and excellent sphericity passes through a slight gap formed between the blade and the image carrier.

  In order to suppress this slip-through, it is necessary to increase the contact pressure between the image carrier and the cleaning blade to enhance the cleaning ability. However, when the contact pressure of the cleaning blade is increased, in the cleaning blade made of an elastic body that has been used conventionally, as shown in FIG. The frictional force is increased, and the cleaning blade 62 is pulled in the moving direction of the image carrier 3, so that the leading edge portion 62 c of the cleaning blade 62 is turned up. When the turned cleaning blade 62 is restored to its original state against the turn, abnormal noise may occur. Further, when the cleaning is continued with the leading edge portion 62c of the cleaning blade 62 turned up, as shown in FIG. 8B, the cleaning blade 62 is separated from the leading edge portion 62c of the leading edge surface 62b by several [μm]. Local wear will occur at the site. If the cleaning is further continued in such a state, the local wear increases, and finally, the leading edge portion 62c is lost as shown in FIG. 8C. If the leading edge portion 62c is missing, the toner cannot be properly cleaned, resulting in poor cleaning. Further, due to such a problem, the usable period of the cleaning blade 62 has been shortened.

  In order to solve such problems, the inventors of the present invention disclosed in Patent Document 1 that the layer thickness of the tip ridge line portion is at least 1 [μm] to 50 [μm] in the vicinity of at least the tip ridge line portion of the cleaning blade made of an elastic blade. The following configuration was proposed in which a surface layer made of an ultraviolet curable resin having a pencil hardness of 7H or more was provided. By applying such a configuration, the cleaning blade is provided with a surface layer having a film hardness of a pencil hardness of 7H, which is harder than a rubber member or the like that is an elastic body, as compared with the prior art prior to Patent Document 1. The friction coefficient of the contact portion could be lowered, and the wear resistance of the cleaning blade could be improved. Further, the frictional force between the image carrier and the cleaning blade can be reduced, and the turning of the ridge line at the tip of the cleaning blade can be satisfactorily suppressed. Further, the pencil hardness surface layer having a pencil hardness of 7H is hard and not easily deformed, so that the turning of the tip ridge line portion of the cleaning blade can be further suppressed.

  As described above, as compared with the prior art prior to Patent Document 1, the deformation near the tip ridge line portion is suppressed, the cleaning failure caused by the deformation is suppressed, and the usable period of the cleaning blade is extended. I was able to do it. However, the recent demand for higher image quality and longer life is very high, and further suppression of cleaning failure and longer usable period of the cleaning blade are desired. The present inventors have also disclosed the invention described in Patent Document 1. Even after the proposal was made, research has been conducted on further improving the cleaning performance and extending the usable period of the cleaning blade.

  Regarding the suppression of the cleaning failure of the cleaning blade and the extension of the usable period of the cleaning blade, conventionally, as in the configuration proposed by the present inventors in Patent Document 1, the deformation in the vicinity of the tip ridge line portion of the elastic blade is known. In order to suppress this and to improve the wear resistance of the tip edge line portion, a surface layer such as a cured resin is provided in the vicinity of the tip portion of the elastic blade, or a hardening process is performed. However, in the cleaning blade using the elastic blade, since the base material itself uses an elastic blade made of polyurethane or the like, the deformation in the vicinity of the tip ridge line portion is suppressed, but the deformation itself occurs. .

  Therefore, the present inventors are unlikely to cause the tip ridge line portion to be turned over or deformed on the base material itself provided with the surface layer or the hardened layer in order to suppress the turning and deformation of the tip ridge line portion of the conventional cleaning blade. It was considered that it would be possible to suppress the deformation in the vicinity of the tip ridge line portion, thereby making it possible to perform a cleaning failure due to the deformation and further increase the usable period of the cleaning blade.

  First, attention was paid to a blade made of a metal member (hereinafter referred to as a metal blade) used in a toner regulating blade or the like. However, conventionally, the metal blade has not been applied as a cleaning blade used for an image carrier because it has the following problems. General metal blades used for conventional toner regulating blades generally have high bending rigidity, so they have low flexibility, and follow fluctuations such as eccentricity of the image carrier and minute waviness of the surface. Can not do it. In addition, there is a problem in that the toner cleaning performance is insufficient because minute toner particles slip through the gap between the member and the member to be cleaned. If the contact pressure between the image carrier and the cleaning blade is increased in order to suppress this slip-through, the metal blade of a general material has a high hardness and may damage the surface of the image carrier. However, there was also a problem that it was much higher than the elastic blade.

  Accordingly, the inventors of the present invention provide flexibility to the metal blade by reducing the thickness of the metal blade within a recoverable range so as to cope with fluctuations such as eccentricity of the image bearing member and minute waviness of the surface. I thought whether I could improve the following ability. However, by simply making the metal blade flexible by reducing the thickness, it is not possible to sufficiently follow fluctuations such as the eccentricity of the image carrier and the minute waviness of the surface, resulting in poor cleaning. . In particular, this poor cleaning became conspicuous with a polymerized toner having a small particle size and excellent sphericity.

  The present invention has been made in view of the above-mentioned problems, and its purpose is to use a blade made of a metal member, to follow fluctuations such as eccentricity of the image carrier and minute waviness of the surface, and good cleaning performance. And a cleaning blade capable of extending the usable period, a process cartridge including the cleaning blade, and an image forming apparatus.

In order to achieve the above object, the invention according to claim 1 is a cleaning blade that contacts the surface of a member to be cleaned and removes powder from the surface of the member to be cleaned, wherein the cleaning blade is made of a metal member, The shape is formed in a strip shape so as to have flexibility, and the tip ridge line portion is covered with a surface layer made of an ultraviolet curable resin or a thermosetting resin.
According to a second aspect of the present invention, in the cleaning blade of the first aspect, the thickness of the metal member is 20 [μm] or more and 200 [μm] or less.
The invention described in claim 3 is characterized in that, in the cleaning blade according to claim 1, the ultraviolet curable resin covering the tip ridge line portion has a pencil hardness of 7H or more.
According to a fourth aspect of the present invention, in the cleaning blade according to the first aspect, the thermosetting resin covering the tip ridge line portion is a fluororesin.
According to a fifth aspect of the present invention, there is provided a process cartridge according to a fifth aspect of the present invention, comprising: an image carrier; cleaning means having a cleaning blade that removes at least residual toner adhering to the surface of the image carrier; and lubrication on the surface of the image carrier. In a process cartridge that integrally supports a lubricant application unit that applies an agent and is detachable from the image forming apparatus main body, the cleaning blade according to any one of claims 1 to 4 is used as the cleaning blade. In addition, the coefficient of friction of the surface of the image carrier is set to 0.2 or less during non-image formation by the lubricant application unit.
According to a sixth aspect of the present invention, there is provided an image forming apparatus comprising: an image carrier; charging means for charging the surface of the image carrier; and latent image formation for forming an electrostatic latent image on the charged surface of the image carrier. Means for developing the electrostatic latent image formed on the surface of the image carrier to form a toner image on the surface of the image carrier; and the toner image on the surface of the image carrier on the transfer body Transfer means for transferring, cleaning means having a cleaning blade that contacts the surface of the image carrier and removes residual toner adhering to the surface of the image carrier, and lubricant application for applying a lubricant on the surface of the image carrier And a friction coefficient of the surface of the image carrier when the non-image is formed by the lubricant application unit. 0. It is characterized in that less.
In the present invention, a metal member that is generally hard to deform in a minute region is used for a cleaning blade that contacts the surface of a member to be cleaned and removes powder from the surface of the member to be cleaned. This eliminates the deformation of the cleaning blade so that the vicinity of the tip ridge portion of the cleaning blade is turned up in a minute region where the tip ridge portion and the surface of the member to be cleaned contact each other like a cleaning blade using a conventional elastic blade. I was able to. The shape of the cleaning blade made of a metal member is formed in a strip shape so as to have flexibility, and the tip ridge line portion is covered with a resin coat layer. As a result, even a cleaning blade made of a metal member can follow the eccentricity of the member to be cleaned and minute undulations on the surface. And the low follow-up with respect to the member to be cleaned which was an obstacle to applying the conventional metal blade to the cleaning blade of the member to be cleaned could be compensated. Moreover, the material which coat | covers the front-end | tip ridgeline part of a cleaning blade is an ultraviolet curable resin or a thermosetting resin. Thus, even if the contact pressure between the member to be cleaned and the cleaning blade is increased in order to suppress slipping of minute toner particles, there is a possibility that the surface of the member to be cleaned may be damaged. It was possible to suppress the increase from becoming very high.

  According to the present invention, it is possible to eliminate problems such as generation of abnormal noise and defective cleaning due to deformation of the conventional cleaning blade so that the vicinity of the tip ridge line portion is turned up, and cleaning that has been shortened due to such problems. The usable period of the blade can be increased. Further, it has become possible to provide a cleaning blade made of a metal member that can be satisfactorily cleaned even if the toner adhering to an image carrier such as a photoconductor is a small particle size toner.

1 is a schematic configuration diagram illustrating a main part of a printer according to an embodiment of the present invention. (A) And (b) is explanatory drawing for demonstrating the measuring method of the circularity of a toner. The perspective view of the cleaning blade which concerns on this embodiment. The expanded sectional view with the cleaning blade concerning this embodiment. The expanded sectional view with the conventional cleaning blade. The figure explaining the coating form of the front-end | tip part of the front-end ridgeline part of the cleaning blade in this embodiment. FIG. 2 is a schematic configuration diagram illustrating a main part of an image forming apparatus used in a verification experiment. Explanatory drawing for demonstrating the state of the front-end | tip ridgeline part of the cleaning blade comprised with the conventional elastic body.

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

  As shown in FIG. 1, the printer includes a drum-shaped photoconductor 3 as an image carrier. The photosensitive member 3 has a drum shape, but may be a sheet shape or an endless belt shape. Around the photosensitive member 3, a charging device 4 as a charging unit, an exposure device (not shown) that forms an electrostatic latent image on the surface of the photosensitive member 3, a developing device 5 that is a developing unit that forms a latent image into a toner image, and toner A transfer device 7 as a transfer means for transferring an image onto a transfer paper as a recording medium, a cleaning device 6 as a cleaning means for cleaning toner remaining on the photoreceptor 3 after transfer, and a lubricant on the surface of the photoreceptor 3. A lubricant application device 10 as a lubricant application means for application, a static elimination lamp (not shown) for neutralizing the photosensitive member 3, and the like are arranged.

  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.

  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 includes a cleaning blade 62 and the like. 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.

  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.

  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 form a toner image, that is, developed. 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 fed from a paper feed unit (not shown) to a transfer region formed between the photoconductor 3 and the transfer device 7 through a nip portion of a pair of registration rollers (not shown). Transferred onto the transfer paper. At this time, the transfer paper is supplied in synchronization with the leading edge of the image at a nip portion of a pair of registration rollers (not shown). 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, the surface of the photosensitive member 3 after the transfer is discharged by a discharging lamp (not shown) after the residual toner after the transfer is removed by the cleaning device 6.

  Further, in this printer, the photosensitive member 3 and the charging device 4, the developing device 5, the cleaning device 6 and the like as process means are housed in the frame 2, and the process cartridge 1 can be integrally attached to and detached from the apparatus main body. It has become. In this embodiment, the photosensitive member 3 as the process cartridge 1 and the process means are integrally replaced. However, like the photosensitive member 3, the charging device 4, the developing device 5, and the cleaning device 6. The structure which replaces | exchanges for a new thing in a unit may be sufficient.

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

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

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

  In such a polymerized toner, as described above, in the configuration in which the elastic blade made of a conventional elastic material such as rubber is used as the cleaning blade 62, the same operation as that when the pulverized toner is removed from the surface of the photoreceptor 3 is performed. Even if the cleaning blade 62 tries to remove the polymerized toner, the polymerized toner cannot be sufficiently removed from the surface of the photoreceptor 3, and a cleaning failure occurs. Therefore, when the contact pressure of the cleaning blade 62 to the photosensitive member 3 is increased to improve the cleaning performance, in the conventional configuration using the elastic blade made of only an elastic body such as rubber, the elastic blade is in an early stage. There was a problem of wear. In addition, the frictional force between the elastic blade and the photoconductor 3 is increased, and the tip ridge line portion that is in contact with the photoconductor 3 of the elastic blade is pulled in the moving direction of the photoconductor 3 to turn the tip ridge line portion. End up. When the tip ridge line portion of the cleaning blade 62 is turned, various problems such as abnormal noise, vibration, and lack of the tip ridge line portion occur.

  Further, conventionally, in order to improve the above-described problems, the deformation of the tip ridge line portion of the elastic blade is suppressed, and at the tip ridge line portion, the resin having higher hardness than the elastic blade is used to reduce the frictional force. Several proposals have been made to provide a coat layer. In all of these proposals, a resin coat layer having a hardness higher than that of the elastic blade is provided on the tip ridge line portion of the elastic blade, thereby suppressing deformation of the tip ridge line portion of the elastic blade and reducing the frictional force. It is based on the technical idea of doing.

  However, the recent demand for higher image quality and longer life is very high, and further suppression of cleaning failure and longer usable period of the cleaning blade have been desired.

  Therefore, in this embodiment, a blade made of a metal member (hereinafter referred to as a metal blade) that has not been conventionally used for an image carrier such as a photoconductor is used as the cleaning blade 62. And the shape is formed in strip shape so that it may have flexibility, and the surface layer coat | covered with the resin coat layer which consists of an ultraviolet curable resin or a thermosetting resin is provided in the front-end ridgeline part.

  Here, in the present embodiment, the surface layer as described above is provided at the tip ridge line portion of the metal blade to which flexibility is imparted, and the fluctuations such as the eccentricity of the image carrier such as the photoconductor and the minute waviness of the surface are detected. This is based on the technical idea of improving the followability, and is different from the technical idea of providing a resin coat layer on the tip edge line portion of the conventional elastic blade.

  FIG. 3 is a perspective view of the cleaning blade 62, and FIG. 4 is an enlarged cross-sectional view of the cleaning blade 62 composed of the metal blade 622 of this embodiment. FIG. 6 is a view for explaining the coating form of the tip that can be applied to the cleaning blade 62. Here, the cleaning blade 62 includes a strip-shaped holder 621 made of a rigid material such as metal or hard plastic, and a metal blade 622 formed in a strip shape so that the shape thereof is flexible. Yes.

  The metal blade 622 has a surface layer 623 formed so as to cover the tip ridge line portion 62c in the vicinity of the tip ridge line portion 62c of the entire metal blade 622 and the lower surface 62b. The metal blade 622 is fixed to one end side of the holder 621 with an adhesive or the like, and the other end side of the holder 621 is supported by the case of the cleaning device 6.

  Further, a surface layer is formed on the tip surface 62a and the blade lower surface 62b to a position separated from the tip ridge line portion 62c that may be in contact with the photosensitive member 3 by the blade thickness. Thereby, the contact pressure of the cleaning blade 62 becomes higher than necessary due to the mounting error of the photosensitive member 3 or the mounting error of the cleaning blade, and the cleaning blade 62 bends more than necessary, and the leading edge portion 62c of the blade lower surface 62b. Even if a location several [μm] away from the photosensitive member 3 is in contact with the photosensitive member 3, or a location several [μm] away from the leading edge portion 62 c of the leading end surface 62 a is in contact with the photosensitive member 3. Since the surface layer 623 is formed, local wear can be suppressed.

  In addition, the metal blade 622 of the present embodiment has a blade thickness of 20 [μm] or more and 200 [μm] or less in order to have flexibility. Here, the reason why the blade thickness is 20 [μm] or more and 200 [μm] or less is that when the blade thickness is 20 [μm], the flexibility is too large, and the photosensitive member of the metal blade 622 is used. This is because the predetermined contact pressure with respect to 3, that is, the linear pressure is lowered and the predetermined linear pressure cannot be maintained. On the other hand, when the blade thickness exceeds 200 [μm], on the contrary, the flexibility is reduced, and the contact pressure of the metal blade 622 against the photosensitive member 3, that is, the linear pressure increases, and the predetermined linear pressure is maintained. This is because it is considered that the surface pressure of the photoreceptor 3 may be damaged as the linear pressure becomes too high.

  The material of the surface layer 623 is preferably an ultraviolet curable resin or a thermosetting resin, and the ultraviolet curable resin is more preferably a pencil hardness of 7H or more. The thermosetting resin is more preferably a fluororesin. A surface layer is provided on the tip ridge line portion 62c of the metal blade to which flexibility is imparted by using these as a resin coating layer and a blade thickness of 20 [μm] or more and 200 [μm] or less, so that the eccentricity of the photoreceptor 3 and the minute surface The followability to fluctuations such as swells could be improved.

  The metal blade 622 of the present embodiment can sufficiently follow fluctuations such as eccentricity of the photoreceptor 3 and minute waviness on the surface, and is a polymer toner having a small particle size and excellent sphericity. It was possible to maintain good cleaning performance over a long period of time.

  In addition, by using an ultraviolet curable resin having a pencil hardness of 7H or more or a thermosetting resin made of a fluorine resin as the material of the surface layer 623, it is possible to suppress wear due to rubbing with the photosensitive member 3 to be extremely small. In addition, the usable period until the metal thin plate layer of the metal blade 622 was exposed became very long. As shown in a verification experiment to be described later, the usable period is about 10 times or more compared to the cleaning blade 62 using the elastic blade 624 made of only an elastic body such as rubber, which has been used conventionally. We were able to.

  Here, the reason why the film hardness when the ultraviolet curable resin is employed as the material of the surface layer 623 is preferably a pencil hardness of 7H or more is that the surface layer 623 is not easily scraped by the photoreceptor 3 by setting the pencil hardness to 7H or more. This is because, with normal linear pressure, the abrasion resistance of the cleaning blade 62 can be improved without damaging the photoreceptor 3, and the cleaning performance can be maintained over time. Then, by applying an ultraviolet curable resin having a pencil hardness of 7H or more to the metal blade 622 that is less likely to be deformed such as turning of the tip ridge line portion 62c, it can be used for a longer period of time than the conventional elastic blade 624. I was able to.

Next, a verification experiment conducted by the applicants will be described.
The durability test was performed by changing the thickness of the metal blade 622 and the material of the surface layer 624. For comparison, the elastic blade 623 was also subjected to an endurance test with and without the surface layer 624.

[Metal blade]
As the metal blade 622, a stainless material (SUS304) was used.
Three types of plate thicknesses of 20 [μm], 50 [μm], and 200 [μm] were prepared.
[Elastic blade]
As the elastic blade 623, urethane rubber 1 having physical properties at 25 [° C.] hardness of 69 degrees and rebound resilience of 50 [%] (manufactured by Toyo Tire & Rubber Co., Ltd.) was prepared. In both cases, the plate thickness is 1800 [μm].

  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.

[Surface layer]
The following were used as the surface layer.
(Surface layer 1)
UV curable resin: PETIA 10 parts Polymerization initiator: Irgacure 184 1 part Solvent: 2-butanone 89 parts Pencil hardness: 9H
(Surface layer 2)
UV curable resin: UN-3320HA 10 parts Polymerization initiator: Irgacure 184 1 part Solvent: 2-butanone 89 parts Pencil hardness: 7H
(Surface layer 3)
Thermosetting resin: PTFE

  The pencil hardness of the surface layer 624 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 about 5 [μm] of the material of the surface layer 624 on a glass plate of 50 [mm] × 50 [mm].

Next, the configuration of the image forming apparatus for which the verification experiment has been performed will be described.
The metal blade and the elastic blade on which the surface layer was formed were fixed with an adhesive to a sheet metal holder that can be mounted on the Ricoh color composite machine imaginio MP C4500, to obtain a prototype cleaning blade. This was similarly attached to a Ricoh color composite machine imagio MP C4500, and image forming apparatuses of Examples 1 to 3, Comparative Example 1, and Comparative Example 2 were produced. Here, the cleaning blade was attached so that the linear pressure was 20 [g / cm] and the cleaning angle was 79 [°].

  In the image forming apparatuses of Examples 1 to 3 and Comparative Examples 1 and 2, as shown in FIG. 7, the solid lubricant 103 and the leveling blade 102 are removed, and the lubricant is applied to the surface of the photoreceptor. It is configured not to be.

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

  The verification experiment was performed in a laboratory environment: 21 [° C.] · 65 [% RH], paper feeding condition: image area ratio 5% chart with 3 prints / job at 50,000 sheets (A4 landscape). And the following items were evaluated.

  As for the coating method for forming the surface layer and the coating thickness, since the plate thickness of the metal blade 622 is thin in this verification experiment, a resin coat layer is provided by dip coating, and the shape of the tip of the resin coat Was a complete film type (round shape) as shown in FIG. The same applies to the elastic blade of Comparative Example 2 that forms the surface layer.

  Here, as is well known, when coating is performed by dip coating, the thickness of the resin coating layer at the tip ridge line portion 62c, which is a corner, is more dependent on the surface tension than the thickness of the resin coating layer separated from the corner. It will be thinner.

  Therefore, in this verification experiment, the coating was performed so that the layer thickness of the surface layer 623 in the direction in which the metal blade 622 contacts the photoreceptor 3 from the leading edge portion 62c is in the range of 1 to 5 [μm]. Specifically, in order to set the layer thickness of the tip ridge line portion 62c, which is a corner portion that becomes thin due to the above-described surface tension, to the above-described range, the layers are perpendicular to the respective surfaces of the tip surface 62a and the blade lower surface 62b. The coating was performed so that the layer thickness from the tip ridge line portion 62c in the direction to 50 [μm] was 5 to 10 [μm].

  If the layer thickness in the direction in contact with the photosensitive member 3 from the leading edge portion 62c is less than 1 [μm], the rigidity of the surface layer itself becomes weak, and the metal thin plate layer at the corner of the leading edge portion 62c of the metal blade 622 is removed. It is exposed at an early stage and comes into contact with the photoreceptor 3. Further, if coating is performed so that the layer thickness in the direction in contact with the photoreceptor 3 from the tip ridge line portion 62c exceeds 5 [μm], the range of the resin coat formed on the tip surface 62a and the blade lower surface 62b becomes long. turn into. If the range of the resin coating formed on the blade lower surface 62b becomes too long, the influence of the hardness of the coating surface layer becomes too strong, and the flexibility imparted by reducing the blade thickness of the metal blade 622 is lost. As a result, the followability to fluctuations such as eccentricity of the photoreceptor is reduced. As a result, it was considered that good cleaning properties could not be obtained.

[Evaluation item]
Occurrence of cleaning failure: Existence (visual observation)
Image at the time of evaluation: Vertical band pattern (with respect to the paper traveling direction) 43 [mm] width, 3 charts
Output 20 sheets (A4 side)
Blade edge wear width: Wear width seen from the bottom side of the blade

  The result of the verification experiment of the cleaning blades of Examples 1 to 3, Comparative Example 1, and Comparative Example 2 is shown below. Here, the layer thickness of the surface layer was measured by a cross section of a metal blade and an elastic blade separately coated in the same manner using a Keyence microscope VHX-100. The sample was a cross-section cut using a trimming razor for SEM sample preparation manufactured by Nisshin EM.

Example 1
Base stainless steel: SUS304
Plate thickness: 20 [μm]
Surface layer: Surface layer 1
Layer thickness at 50 [μm] from edge: 5 μm
Blade edge wear width: 5 [μm]
Occurrence of cleaning failure: None Occurrence of abnormal noise: None

(Example 2)
Base stainless steel: SUS304
Plate thickness: 50 [μm]
Surface layer: Surface layer 2
Layer thickness at 50 [μm] from edge: 5 μm
Blade edge wear width: 3 [μm]
Occurrence of cleaning failure: None Occurrence of abnormal noise: None

(Example 3)
Base stainless steel: SUS304
Plate thickness: 200 [μm]
Surface layer: Surface layer 3
Layer thickness at 50 [μm] from edge: 5 μm
Blade edge wear width: 2 [μm]
Occurrence of cleaning failure: None Occurrence of abnormal noise: None

(Comparative Example 1)
Base urethane rubber: Urethane rubber 1
Surface layer: None Layer thickness at 50 [μm] from edge: None Blade edge wear width: 30 [μm]
Occurrence of defective cleaning: Three strips of defective cleaning Occurrence of abnormal noise: None

(Comparative Example 2)
Base urethane rubber: Urethane rubber 1
Surface layer: 1
Layer thickness at 50 [μm] from edge: 10 μm
Blade edge wear width: 10 [μm]
Occurrence of cleaning failure: 1 band cleaning failure Occurrence of abnormal noise: None

  Table 1 above summarizes the results of verification experiments of Examples 1 to 3, Comparative Example 1, and Comparative Example 2.

  In Examples 1 to 3, the wear width of the tip ridge line portion 62c of the metal blade 622 after the 50,000 sheet passing test can be suppressed to 5 [μm] or less. This is because the front edge portion 62c of the metal blade 622 is provided with the surface layers 1 to 3 to suppress wear due to friction with the photoreceptor 3, and the metal blade 622 itself is generally used. This is presumably because it is made of a metal member that is difficult to deform in a minute region. Therefore, it is considered that the wear width of the tip ridge line portion 62c was not wide. Further, it has been said that, in a conventional cleaning blade made of only an elastic blade, when the wear width of the tip ridge line portion 62c reaches 30 to 50 [μm], a cleaning failure occurs.

  In Examples 1 to 3, polymerized toners having a spherical toner particle size of 0.98 and an average particle diameter of 4.9 [μm] and having a small particle diameter were used. Even in the cleaning evaluation of continuous solid images of 1,000 sheets over time, it was possible to suppress poor cleaning, and good cleaning properties were obtained. In the first to third embodiments, the surface layers 1 to 3 are provided on the tip ridge line portions 62c of the metal blade 622 to which flexibility is added by reducing the blade thickness, so that the flexibility is improved. This is considered to be because the low follow-up property against the eccentricity of the photosensitive member 3 and the minute waviness of the surface in the case of only the added metal blade 622 was compensated.

  In addition, in Examples 1 to 3, no chatter noise was confirmed. This is because the surface layers 1 to 3 are respectively provided on the leading edge portions 62c of the metal blade 622 so that wear due to rubbing against the photoreceptor 3 is suppressed to a very small level, and the metal blade 622 itself is not deformed. This is considered to be because it is made of a metal member and has a necessary followability to the fluctuation of the photoreceptor 3 of the metal blade 622. In the first place, the chatter noise is a very small region where the tip ridge line portion 62c of the cleaning blade 62 and the photosensitive member 3 are in contact with each other, and the tip ridge line portion 62c is photosensitive by the frictional force between the tip ridge line portion 62c of the cleaning blade 62 and the photosensitive member 3. Since it is an abnormal noise generated by chatter vibration caused by a slight deformation in the moving direction of the body 3, it is considered that the noise was not generated in the first to third embodiments for the reason described above.

  Further, the wear width of the tip ridge line portion 62c of the elastic blade 624 of Comparative Example 1 described below was 30 [μm] after the 50,000 sheet passing test. That is, it was the same value as the lower value of the wear width of the tip ridge line portion 62c where the conventional cleaning failure occurs. Here, the wear width of the tip ridge line portion 62c is generally proportional to the number of sheets passing, and compared with the wear width of the tip ridge line portion 62c of the second embodiment being 3 [μm], the first to first embodiments. 3, the usable time is about 10 times or more.

  On the other hand, in Comparative Example 1, no chatter noise was confirmed, but the wear width of the tip ridge line portion 62c of the elastic blade 624 was 30 [μm] after the 50,000 sheet passing test, which has been said conventionally. This was the same value as the lower value of the wear width of the leading edge line portion 62c where the cleaning failure that occurred. Also in the cleaning evaluation, three streaky cleaning defects occurred. The reason for the occurrence of poor cleaning and the reason why the wear width of the tip ridge line portion 62c is 30 [μm] is because the problem of the cleaning blade 62 composed only of the above-described conventional elastic blade occurs. It is considered a thing.

Further, in Comparative Example 2, no chatter noise was confirmed, but the wear width of the tip ridge line portion 62c was 10 [μm] after the 50,000 sheet passing test, and in the cleaning evaluation, streak-like cleaning failure was found. One location occurred. This is because the surface layer 1 similar to that in Example 1 was formed, so that the abrasion due to the rubbing against the photosensitive member 3 was reduced compared with Comparative Example 1, and the deformation of the tip ridge line portion 62c of the elastic blade 624 was also suppressed. This is thought to be due to this. However, since the tip ridge line portion 62c itself of the elastic blade 624 is deformed, it is considered that the wear width and the cleaning failure of the tip ridge line portion 62c could not be suppressed as in the first to third embodiments.

  In the above-described embodiment, the example in which the present invention is applied to the cleaning device that cleans the toner on the surface of the photoreceptor 3 as the image carrier has been described, but the present invention is not limited to this. For example, the toner image formed on the photoreceptor 3 is primarily transferred to an intermediate transfer belt as an image carrier, and the toner image primarily transferred to the intermediate transfer belt is secondarily transferred to transfer paper. The present invention can be applied to an intermediate transfer belt cleaning device that cleans transfer residual toner.

  In the above-described embodiment, a monochrome printer has been described as an example of a so-called monochrome image forming apparatus, but a color image forming apparatus may be used.

As described above, the cleaning blade 62 that contacts the surface of the photoreceptor 3 of the present embodiment and removes powder from the surface of the photoreceptor 3 is generally made of a metal member that is difficult to deform in a minute region. A metal blade 622 is used. Thus, like the cleaning blade 62 using the conventional elastic blade 624, the vicinity of the tip ridge line portion 62c of the cleaning blade 62 is turned up in a minute region where the tip ridge line portion 62c contacts the surface of the photosensitive member 3. It is possible to eliminate deformation. Accordingly, it is possible to eliminate problems such as generation of abnormal noise and defective cleaning due to the deformation of the conventional cleaning blade 62 so that the vicinity of the front edge portion 62c of the cleaning blade 62 is turned up. The possible period can be lengthened. Moreover, the shape of the metal blade 622 is formed in a strip shape so as to have flexibility, and the tip ridge line portion 62c is covered with a surface layer made of a resin coat layer. As a result, the cleaning blade 62 composed of the metal blade 622 can follow the eccentricity of the photosensitive member 3 and the minute waviness of the surface. Further, it is possible to compensate for the low followability of the photoreceptor 3 as the member to be cleaned, which has been an obstacle to applying the metal blade made of the conventional metal member to the cleaning blade of the photoreceptor 3 as the member to be cleaned. did it. Therefore, it is possible to provide the cleaning blade 62 composed of the metal blade 622 that can be satisfactorily cleaned even if the toner adhering to the photoconductor 3 is a small particle size toner. Moreover, the material which coat | covers the front-end | tip ridgeline part 62c of the metal braid | blade 622 is an ultraviolet curable resin or a thermosetting resin. As a result, even if the contact pressure between the photoconductor 3 and the metal blade 622 is increased in order to suppress the passage of minute toner particles, there is a possibility that the surface of the photoconductor 3 may be damaged. It was possible to suppress the height from being extremely higher than that of the blade 624. Therefore, it is possible to provide the cleaning blade 62 composed of the metal blade 622 that can be cleaned satisfactorily without damaging the surface of the photoconductor 3 even when the toner adhering to the photoconductor 3 is a small particle size toner. It has become possible.
In the cleaning blade 62 of the present embodiment, the thickness of the metal blade 622 made of a metal member is 20 [μm] or more and 200 [μm] or less. With this configuration, the metal blade 622 can be given good flexibility.
In the cleaning blade 62 of the present embodiment, the ultraviolet curable resin that covers the tip ridge line portion 62c of the metal blade 622 has a pencil hardness of 7H or more. With this configuration, wear due to rubbing against the photoreceptor 3 can be suppressed to a very low level, and the usable period until the metal thin plate layer of the metal blade 622 is exposed becomes very long. It was. As shown in a verification experiment to be described later, the usable period is about 10 times or more compared to the cleaning blade 62 using the elastic blade 624 made of only an elastic body such as rubber, which has been used conventionally. We were able to.
In the cleaning blade 62 of the present embodiment, the thermosetting resin that covers the tip ridge line portion 62c of the metal blade 622 is a fluororesin. With this configuration, wear due to rubbing against the photoreceptor 3 can be suppressed to a very low level, and the usable period until the metal thin plate layer of the metal blade 622 is exposed becomes very long. It was. As shown in a verification experiment to be described later, the usable period is about 10 times or more compared to the cleaning blade 62 using the elastic blade 624 made of only an elastic body such as rubber, which has been used conventionally. We were able to.
Further, the process cartridge 1 according to the present embodiment is configured to apply a lubricant on the surface of the photoreceptor 3, the cleaning device 6 having the cleaning blade 62 that removes at least the residual toner adhered on the surface of the photoreceptor 3, and the surface of the photoreceptor 3. The lubricant application device 10 is integrally supported. Further, it is detachable from the printer main body, uses any one of the above-described cleaning blades 62 as a cleaning blade, and has a coefficient of friction of 0.2 on the surface of the photoreceptor 3 when the non-image is formed by the lubricant application device 10. It is as follows. With this configuration, it is possible to obtain the operational effects of any of the above-described cleaning blades 62, and it is possible to further reduce wear due to friction with the photosensitive member 3, and a metal blade The usable period until the metal thin plate layer 622 is exposed can also be made longer.
The printer according to the present embodiment includes a photosensitive member 3, a lubricant coating device 10 that charges the photosensitive member 3, an exposure device that forms an electrostatic latent image on the surface of the charged photosensitive member 3, and the surface of the photosensitive member 3. The developing device 5 that develops the electrostatic latent image formed on the surface of the photosensitive member 3 to form a toner image on the surface of the photosensitive member 3, the transfer device 7 that transfers the toner image on the surface of the photosensitive member 3 to the transfer member, and the photosensitive member In a printer provided with a cleaning device 6 having a cleaning blade for removing residual toner adhering to the surface of the photosensitive member 3 in contact with the surface of the photosensitive member 3, and a lubricant applying device 10 for applying a lubricant on the surface of the photosensitive member 3. Any one of the above-described cleaning blades 62 is used as the cleaning blade, and the coefficient of friction of the surface of the photoreceptor 3 is set to 0.2 or less when the non-image is formed by the lubricant application device 10. With this configuration, it is possible to obtain the operational effects of any of the above-described cleaning blades 62, and it is possible to further reduce wear due to friction with the photosensitive member 3, and a metal blade The usable period until the metal thin plate layer 622 is exposed can also be made longer.

DESCRIPTION OF SYMBOLS 1 Process cartridge 2 Frame 3 Photoconductor 4 Charging device 5 Developing device 6 Cleaning device 7 Transfer device 10 Lubricant coating device 14 Transfer belt 51 Developing roller 52 Supply screw 53 Stirring screw 54 Doctor 62 Cleaning blade 62a Tip surface 62b Blade lower surface 62c Tip edge portion 101 Fur brush 103 Solid lubricant 621 Holder 622 Metal blade 623 Surface layer 624 Elastic blade

JP 2009-227033 A

Claims (6)

In the cleaning blade that contacts the surface of the member to be cleaned and removes powder from the surface of the member to be cleaned,
The cleaning blade is made of a metal member, and the shape of the cleaning blade is formed in a strip shape so as to have flexibility, and the edge of the tip is covered with a surface layer made of an ultraviolet curable resin or a thermosetting resin. And a cleaning blade. The cleaning blade of claim 1.
A cleaning blade, wherein the thickness of the metal member is 20 [μm] or more and 200 [μm] or less. The cleaning blade according to claim 1, wherein
A cleaning blade, wherein the ultraviolet curable resin covering the tip ridge line portion has a pencil hardness of 7H or more. The cleaning blade according to claim 1, wherein
A cleaning blade, wherein the thermosetting resin that covers the tip ridge is a fluororesin. An image carrier;
Cleaning means having at least a cleaning blade for removing residual toner adhering to the surface of the image carrier;
In a process cartridge that integrally supports a lubricant application unit that applies a lubricant on the surface of the image carrier, and is detachable from the image forming apparatus main body.
The cleaning blade according to any one of claims 1 to 4 is used as the cleaning blade, and the coefficient of friction of the surface of the image carrier is set to 0.2 or less during non-image formation by the lubricant application unit. Process cartridge. An image carrier;
Charging means for charging the surface of the image carrier;
A latent image forming means for forming an electrostatic latent image on the surface of the charged image carrier;
Developing means for developing the electrostatic latent image formed on the surface of the image carrier and forming a toner image on the surface of the image carrier;
Transfer means for transferring the toner image on the surface of the image carrier to a transfer member;
Cleaning means having a cleaning blade that contacts the surface of the image carrier and removes residual toner adhering to the surface of the image carrier;
In an image forming apparatus provided with a lubricant application means for applying a lubricant on the surface of the image carrier,
The cleaning blade according to any one of claims 1 to 4 is used as the cleaning blade, and the coefficient of friction of the surface of the image carrier is set to 0.2 or less during non-image formation by the lubricant application unit. Image forming apparatus.

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