JP4961754B2 - Cleaning device and image forming apparatus - Google Patents

Description

  The present invention relates to a cleaning device that cleans an image carrier and an image forming apparatus that forms a toner image.

  Conventionally, so-called xerographic (electrophotographic) image forming apparatuses have been widely used as printers, copiers, and facsimiles. A toner image is formed on the surface of the image forming apparatus and the toner image is carried thereon. Image carrier (electrophotographic photosensitive member), charging device for charging the surface of the image carrier, exposure device for exposing the surface of the charged image carrier to form an electrostatic latent image, and electrostatic latent image as toner A developing device that forms a toner image by developing the toner image, a transfer device that transfers the toner image from the image carrier to a recording paper, a fixing device that fixes the toner image on the recording paper, and the image carrier after the transfer of the toner image A cleaning device or the like is provided for removing toner remaining on the toner.

  In recent years, with respect to this image forming apparatus, further speeding up and longer life have been achieved by technical progress of each member and system. Along with this, the demand for high-speed compatibility and high reliability of each subsystem such as a developing device and a cleaning device is higher than before.

  In particular, an image carrier used for image writing and a cleaning device that removes untransferred toner from the surface of the image carrier are subjected to a lot of stress due to sliding between the image carrier and the cleaning device, and are scratched and worn. Image defects due to chipping and the like are likely to occur, and demands for high-speed compatibility and high reliability are further increased.

  In addition, there is a strong demand for high image quality, and the toner has been made in a medium mainly composed of water as a method for producing a toner that satisfies the quality by reducing the particle size of the toner, making the particle size distribution uniform, and making it spherical. So-called chemical toners have been actively developed. As a result, it has recently become possible to obtain an image of the so-called photographic quality, but on the other hand, removal of untransferred toner has become more difficult.

In response to this situation, as disclosed in Patent Document 1, as means for removing toner and paper powder remaining on the surface of the image carrier or the intermediate transfer member, a knitted fabric, a woven fabric or a nonwoven fabric made of fine fibers is used. An invention that uses is known. In the invention described in Patent Document 1, the non-woven fabric is supplied from a cleaning member supply device that holds the non-woven fabric wound around a roll, and the non-woven fabric is pressed against an image carrier or an intermediate transfer body by a press-contact roll. The image carrier and the intermediate transfer member are cleaned, and then the nonwoven fabric and the like are collected by the cleaning member winding device. Moreover, as disclosed in Patent Document 2 and Patent Document 3, a nonwoven fabric is affixed to a foamed elastic member or a sheet-shaped elastic member having a square cross section, mainly for the purpose of removing paper dust. An invention in which the image carrier is cleaned is also known. Further, as disclosed in Patent Document 4, the surface friction of the image carrier is achieved by installing a non-woven fabric made of fine fibers that are also attached to an elastic member on the downstream side of the cleaning device and the upstream side of the charging device. Inventions in which the coefficient is kept low are also known.
JP-A-10-1116011 JP 2000-206850 A JP 2000-227743 A JP 2002-333805 A

  However, in foamed elastic bodies such as urethane foam, urethane rubber, sheet-like elastic bodies such as SUS thin plates or PET films, etc., the hardness and spring constant generally have an environmental dependency that is proportional to temperature. have. For this reason, in a configuration in which a nonwoven fabric or the like is attached to an elastic body and pressed against the image carrier, the pressing pressure of the nonwoven fabric or the like decreases under high temperature and high humidity and increases under low temperature and low humidity. Therefore, in high temperature and high humidity environments where discharge stress is large and image flow is likely to occur, the scraping performance of the discharge products sticking to the surface of the image carrier becomes insufficient. There is a problem in that the wear of the image carrier is promoted and the image quality is deteriorated.

  In view of the above circumstances, an object of the present invention is to provide a cleaning device and an image forming apparatus capable of maintaining both high cleaning performance and good image quality over a long period of time.

The cleaning device of the present invention that achieves the above object provides:
In a cleaning device for cleaning an image carrier on which a toner image is formed,
A rubbing member that is pressed against the image carrier and rubs on the image carrier;
And a pressing portion that presses the rubbing member against the image carrier at a predetermined high temperature and presses with a pressing force stronger than a pressing force at a predetermined low temperature lower than the high temperature.

  The cleaning device of the present invention has a form that “the pressing portion has a bimetal, and the bimetal generates the pressing force” or “the pressing portion has an air spring, and the pressing force is generated by the air spring. The form of “is what produces” is typical.

  According to the cleaning device of the present invention, the bimetal or the air spring generates a strong pressing force at a high temperature where a high cleaning force is required to improve the cleaning power, and the pressing force is weakened at a low temperature to avoid wear of the image carrier. can do. As a result, both high cleaning performance and good image quality can be maintained over a long period of time.

  In addition, it is preferable that the cleaning device of the present invention further includes a removing unit that removes unnecessary materials on the image carrier rubbed by the rubbing member by a potential difference from the image carrier.

  When the image carrier is rubbed by the rubbing member, discharge products and the like attached to the surface of the image carrier become aggregates that can be easily removed from the image carrier. The removal unit that removes the image carrier with a potential difference can remove the image carrier without damaging it. For this reason, according to the cleaning device having such a removal section, the life of the image carrier is extended, and the image quality is maintained for a longer time.

  In the cleaning device of the present invention, it is also preferable that the rubbing member has a cloth made of fine fibers having a diameter of 10 μm or less, and the image carrier is rubbed with the cloth. Since the above-mentioned aggregate is efficiently generated by appropriately entanglement of toner, discharge products, and the like on a cloth made of such fine fibers, the cleaning apparatus having such a cloth as a rubbing member is more suitable. High cleaning performance can be obtained.

Furthermore, the cleaning device of the present invention includes:
The rubbing member has a cloth made of fine fibers having a diameter of 10 μm or less and a foamed elastic body covered with the cloth, and the image carrier is rubbed with the cloth.
The pressing portion presses the sliding elastic member against the image carrier by pressing the foamed elastic body of the rubbing member with the pressing force. "
This form is also preferable.

  Since the rubbing member having such a foamed elastic body and a cloth is in wide and uniform contact with the image carrier, the above-mentioned aggregate is efficiently generated, and higher cleaning performance can be obtained.

The image forming apparatus of the present invention that achieves the above object provides:
An image carrier on which a toner image is formed and which carries and moves the toner image;
A charging unit for charging the image carrier;
An exposure unit that forms an electrostatic latent image by irradiating exposure light onto the image carrier charged by the charger;
A developing unit that forms a toner image by developing the electrostatic latent image formed by the exposure unit with toner;
A transfer unit that transfers the toner image formed by the developing unit onto a predetermined transfer object;
A rubbing member that is pressed against the image carrier after the toner image is transferred by the transfer unit and rubs on the image carrier;
And a pressing portion that presses the rubbing member against the image carrier at a predetermined high temperature and presses with a pressing force stronger than a pressing force at a predetermined low temperature lower than the high temperature.

  According to the image forming apparatus of the present invention, a strong pressing force is generated at a high temperature where a high cleaning force is required to improve the cleaning force, and the pressing force is weakened at a low temperature to avoid wear of the image carrier. As a result, both high cleaning performance and good image quality can be maintained over a long period of time.

  It should be noted that the image forming apparatus according to the present invention is only shown in its basic form here, but this is merely to avoid duplication, and the image forming apparatus according to the present invention has only the above basic form. Instead, various forms corresponding to the forms of the cleaning device described above are included.

  As described above, according to the cleaning device and the image forming apparatus of the present invention, both high cleaning performance and good image quality can be maintained over a long period of time.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a schematic sectional view showing a first embodiment of the present invention.

  FIG. 1 shows a printer 100 which is a first embodiment of the image forming apparatus of the present invention. The printer 100 is a so-called rotary type full-color printer.

  The printer 100 is typified by a photosensitive drum 101 that rotates in the direction of arrow A in the figure, an electrostatic latent image or a toner image formed on the surface, a charger 102 that charges the photosensitive drum 101, and a personal computer. An exposure unit 103 that inputs image data output from an external device and irradiates the photosensitive drum 101 with exposure light modulated based on the image data to form an electrostatic latent image; A developing unit 104 that applies toner to an image to form a toner image, an intermediate transfer belt 105 that contacts the photosensitive drum 101 and circulates in the direction of arrow B in the figure, and a toner formed on the photosensitive drum 101 A primary transfer roll 106 for primary transfer of an image to the intermediate transfer belt 105, a photoreceptor cleaner 107 for cleaning the photoreceptor drum 101 after the primary transfer, A secondary transfer unit 109 that secondary-transfers the toner image primary-transferred onto the inter-transfer belt 105 from the internal tray 108a or the manual feed tray 108b to the paper transported by the transport roll 108c, and an intermediate after the secondary transfer. A belt cleaner 110 that cleans the transfer belt 105, a fixing device 111 that fixes the toner image transferred onto the sheet by heating and pressurizing the sheet, and a stacking tray 112 on which the sheet on which the toner image is fixed are stacked. It has been.

  The development unit 104 incorporates four development units 104Y, 104M, 104C, and 104K corresponding to the four colors of CMYK, and each development unit 104Y, 104M, 104C, and 104K includes toner and a carrier of each color. A two-component developer is contained. The development unit 104 is sequentially rotated by 90 degrees, whereby development is performed with toners of four colors of CMYK, and toner images of the respective colors are formed. The toner images of the respective colors are superimposed on each other when transferred to the intermediate transfer belt 105 by the primary transfer roll 106 to form a full color toner image, and the full color toner image is transferred to the paper by the secondary transfer device 109. Is done.

  Here, the photosensitive drum 101 corresponds to an example of an image carrier according to the present invention, the charger 102 corresponds to an example of a charging unit according to the present invention, and the exposure unit 103 corresponds to an exposure unit according to the present invention. It corresponds to an example. The developing unit 104 corresponds to an example of the developing unit referred to in the present invention, the intermediate transfer belt 105 corresponds to an example of the transfer object referred to in the present invention, and the primary transfer roll 106 corresponds to the transfer unit referred to in the present invention. It corresponds to an example. The photoreceptor cleaner 107 corresponds to an embodiment of the cleaning device of the present invention.

  FIG. 2 is a schematic cross-sectional view showing the photoconductor cleaner in the first embodiment.

  The photoconductor cleaner 107 is provided at a position fixed with respect to the rotation of the photoconductor drum 101, and includes a brush 107a in contact with the surface of the photoconductor drum 101, a collection roll 107b in contact with the brush 107a, and a collection roll. And a scraper 107c in contact with 107b. A positive cleaning bias is applied to the brush 107a and the collecting roll 107b, and the electric field generated by the cleaning bias causes the brush 107a to be removed from the surface of the photosensitive drum 101 such as toner, discharge products, and paper dust. And the collection roll 107b collects the unnecessary matter accumulated on the brush 107a. The scraper 107 c scrapes off unnecessary materials collected by the collection roll 107 b into the photoreceptor cleaner 107.

  Here, the recovery roll 107b is made of a thermosetting resin, and is hardened (crosslinked) by heating to be formed. Therefore, the post-molding shrinkage hardly occurs, and is extremely superior to the dimensional accuracy required for the recovery roll. Examples of the thermosetting resin used in the recovery roll include phenol resin, urea resin, melamine resin, unsaturated polyester, epoxy resin, polyimide resin, etc. Among them, phenol resin has high dimensional accuracy and is easy to mold, In addition, since it is excellent in surface smoothness of the molded product and is inexpensive, it is optimal as a material used for the collecting roll of the present invention.

  Furthermore, if the flexural modulus of elasticity of the collecting roll in JIS-K7171; 94 is less than 700 Kpa, the collecting roller is bent and the contact position and the amount of biting with the brush member and the blade cannot be kept constant. If a material with low flexural modulus is used and the rigidity of the collecting roller is increased to maintain rigidity, molding shrinkage increases and the desired dimensional accuracy cannot be obtained, but the weight increases, molding time increases, Costs increase due to various problems such as the need for processing. Further, the collection roll is constantly in contact with the brush member and the scraper. Accordingly, it is required to be made of a material that is resistant to wear. When the wear amount exceeds 20 mg in JIS-K6902; 98, the life of the collecting roller is shortened and must be frequently replaced. Further, since the amount of wear is small, the contact pressure and biting amount of the brush member and blade can be set large, and the image carrier can be stably cleaned over a long period of time. In addition, since it becomes possible to form with high dimensional accuracy and the roller is very strong against scraping, it is preferable that the Rockwell hardness (M scale) of the recovery roll in JIS-K7202; 95 is 100 or more. .

Further, for the purpose of increasing the rigidity and adjusting the electric resistance within a predetermined range, one or more fillers may be filled in the collecting roll. Fillers here include carbon black, carbon powder, graphite, magnetic powder, zinc oxide, tin oxide, metal oxides such as titanium oxide, metal sulfides such as copper sulfide and zinc sulfide, strontium, barium, rare earth, etc. So-called hard ferrite, magnetite, ferrite such as copper, zinc, nickel and manganese, or those whose surfaces are subjected to conductive treatment as necessary, copper, iron, manganese, nickel, zinc, cobalt, barium, aluminum, tin, lithium, Metal oxide solid solution obtained by firing at high temperature selected from oxides, hydroxides, carbonates or metal compounds containing different metal elements such as magnesium, silicon and phosphorus, so-called composite metal oxide, tin , Metal powders such as iron, copper, and aluminum, metal fibers, and glass fibers. When the electrical resistance of the recovery roll is lower than 1 × 10 ⁵ Ω, charge injection occurs and the polarity of the fine powder such as toner and paper powder scraped off by the brush member is reversed, making it impossible to be electrically adsorbed. End up. On the other hand, if the electrical resistance of the collection roll exceeds 1 × 10 ¹⁰ Ω, so-called charge-up occurs in which charge is accumulated on the collection roller, and it is impossible to electrically adsorb fine powder such as toner and paper powder. The electrical resistance of the collecting roll when 500 V is applied is in the range of 1 × 10 ⁵ to 1 × 10 ¹⁰ Ω, preferably 1 × 10 ⁶ to 1 × 10 ⁸ Ω.

  There is a potential difference between the cleaning bias applied to the brush 107a and the recovery roll 107b, the potential difference between the brush 107a and the recovery roll 107b is | 100V | or more, preferably | 200V | or more, and the upper limit is regulated by the bias leak limit. And is preferably suppressed to | 650V | or less.

The brush 107a is formed in a roll shape in which countless fibers are arranged on the outer periphery of the rotating shaft. The brush is arranged at a position where the tip of the fiber slightly bites into the photosensitive drum, and the peripheral surface of the brush rotates in a direction opposite to the direction of movement of the peripheral surface of the photosensitive drum, and at this time, by sliding contact with the photosensitive drum. The toner and external additives are peeled off from the surface of the photosensitive drum and are transported to a collecting roll. The amount of biting between the brush and the photosensitive drum is desirably 0.1 to 2.5 mm, preferably 0.2 to 2.0 mm, and more preferably 0.5 to 1.5 mm.
Specific materials for brushes include resin fibers such as nylon, acrylic, polyolefin, polyester, etc., and conductive powder and ionic conductive agents are added to provide conductivity, or the interior of each fiber. Alternatively, an external conductive layer can be used, and the resistance value is preferably 10 ² to 10 ¹⁵ Ω as a single fiber, more preferably 10 ⁴ to 10 ¹³ , and the fiber thickness is 30d (denier) or less, preferably 20d less, more preferably 2D～10d, the density of the fibers 20,000 / inch ² or more, preferably 30,000 / inch ² or more, more preferably present 60,000 / Inch ² or more. Specific examples include Beltron (manufactured by Kanebo), SA-7 (manufactured by Toray), and UU nylon (manufactured by Unitika). Furthermore, it is more preferable that the material imparting conductivity is uniformly blended in the fiber because of excellent cleaning maintenance.

  The scraper 107c is formed of a stainless steel or phosphor bronze metal sheet from the viewpoint of high durability and low cost, and its thickness is about 0.02 to 2 mm, preferably 0.05 to 1 mm. Used for.

  Within the photoreceptor cleaner 107, a fine fiber cloth 107d that slidably rubs the surface of the photoconductor drum 101 upstream of the brush 107a with respect to the rotation of the photoconductor drum 101, and the fine fiber cloth 107d is attached to the surface of the photoconductor drum 101. A support member 107e is also provided to press against. The fine fiber cloth 107d corresponds to an example of a rubbing member according to the present invention, and the support member 107e corresponds to an example of a pressing portion according to the present invention.

  The fine fiber cloth 107d is rubbed against the surface of the photoconductive drum 101 to remove toner and external additives and temporarily held between the fibers, and the surface of the photoconductive drum 101 is further held with the held toner. Is efficiently removed from discharge products and the like strongly adhering to the surface of the photosensitive drum 101. Unnecessary items such as toner, external additives, and discharge products are temporarily held between the fibers of the fine fiber cloth 107d. When a certain amount is reached, an aggregate is formed and the fine fiber cloth 107d forms the photosensitive drum 101. It overflows to the surface and is efficiently removed by the brush 107a.

  The fine fiber cloth 107d is a non-woven fabric made of ultrafine fibers, and it is easy to hold the toner densely by forming a micro gap between the surface and the contact surface of the photosensitive drum, and thereby the discharge product adhered to the surface of the photosensitive drum. And external additives can be removed uniformly.

  Here, the ultrafine fiber means 0.2d to 1.0d, typically 0.2d to 0.5d, and the fiber of 0.2d or less is called a superfine fiber. The fiber diameter is about 1 μm to 5 μm, and those having a diameter of 1 μm or less are called ultrafine fine fibers. In the present invention, ultrafine fibers can be handled in the same manner as the ultrafine fibers. The ultrafine fibers are composed of polyester fiber, polyamide fiber, polyvinyl alcohol fiber, polyvinylidene chloride fiber, polyvinyl chloride fiber, acrylic fiber, polyolefin fiber, polyurethane fiber, polyethylene fiber, polypropylene fiber, synthetic fiber, acetate, etc. , Semi-synthetic fibers, regenerated fibers such as rayon, cupra and polynosic, natural fibers made of pulp, silk, cotton, hemp, asbestos and wool can be used. Alternatively, a core-sheath type or side-by-side type composite fiber formed by combining a plurality of these fibers can also be used.

  These ultrafine fibers can be obtained by the following method. For example, there is a melt-blowing method in which the fiber is made finer by spinning the fiber from a nozzle and applying compressed air. Also, the cross-sectional shape is, for example, a sea-island type fiber in which other components are arranged in islands in one component, a multi-bimetal type in which different components are laminated in layers, or a chrysanthemum type in which one component is arranged radially in another component It can be obtained by dividing (orange type) fiber (hereinafter, these composite fibers that can be divided into ultrafine fibers are referred to as “divided fibers”). As a combination of resin components constituting the splittable fiber, for example, when two resin components are used, different materials such as a polyamide resin and a polyester resin, a polyamide resin and a polyolefin resin, a polyester resin and a polyacrylonitrile resin are used. There are similar resins, such as polyethylene and polypropylene. These split fibers are mechanically actuated (for example, splitting by a fluid flow such as water flow, splitting by pressing a pair of rolls, splitting by pressing a flat plate press device, etc.) and chemical action (for example, removal of resin components by a solvent or It is also possible to obtain ultrafine fibers by dividing by swelling or the like.

  There are two methods for processing fibers into fabrics: a method in which yarns are knitted to form a two-dimensional material, and a method in which fabrics are made directly from fibers. The latter allows fibers to be bonded to each other or mechanically entangled. This is processed into a sheet shape, which is called a non-woven fabric. Although the cloth obtained by any of the methods can be used for the rubbing member of the present invention, a nonwoven fabric is desirable in that the cloth has high strength and density, is highly flexible, and can hold the toner well between the fibers.

  The manufacturing process of a nonwoven fabric generally consists of two processes, a fiber web formation process and an interfiber bonding process. First, a fiber web is formed. As a method of forming the fiber web, for example, a dry method in which short fibers (15 to 100 mm) are formed in a fixed direction or randomly using a machine called a card or an air flow called an air array, or very short fibers are formed. There are a wet method in which it is dispersed in water and rolled up into a net-like net, and a spunbond method in which a melted raw resin is directly eluted from the tip of a nozzle and spun to form a fleece with continuous fibers. The fibers are then bonded together. As a method of bonding between fibers, a chemical bond method in which an adhesive resin of an emulsion system is attached to a fiber web by a method such as impregnation or spraying, heated and dried to bond the intersections of the fibers, and thermocompression bonding is performed between hot rolls. Alternatively, a thermal bond method that applies hot air to bond the fibers together, a needle punch method that repeatedly stabs with a needle that moves up and down at a high speed, and entangles the fibers with protrusions called barbs engraved on the needle, a high pressure water stream is injected into a columnar shape, and the fibers are There is a water entanglement method to entangle.

If a fiber web is formed from mechanically splittable fibers and the fibers are entangled by needle punching or fluid flow, the fibers can be split at the same time, which is preferable in manufacturing.
The amount of the ultrafine fiber is preferably 20 parts by weight or more, but the more the fiber is, the more uniform the fiber sheet surface. Therefore, the ultrafine fiber is most preferably 100 parts by weight.
As the non-woven fabric as described above, for example, Toraysee, Exeine (above made by Toray Industries, Inc.), Sabina Minimax, Krauzen (above made by Kanebo Inc.), Miemie (produced by Mitsubishi Rayon Co., Ltd.), Microstar (produced by Teijin Ltd.) ), Benlyse, Luxer, Bencot (made by Asahi Kasei Kogyo Co., Ltd.), biodegradable nonwoven fabric (manufactured by Kanai Important Industry Co., Ltd.), FLEXILON (manufactured by Veratech Japan Co., Ltd.), Kuraray Flex (made by Kuraray Co., Ltd.), Saffron (manufactured by Sansho Co., Ltd.) ), Miracle cloth (manufactured by Daiwa Boseki Co., Ltd.), Sontara (manufactured by DuPont Japan), KF paper (manufactured by Toyobo Co., Ltd.), Pal cloth (manufactured by Honshu Paper Co., Ltd.), and the like.

  The support member 107e that presses the fine fiber cloth 107d against the surface of the photosensitive drum 101 is formed of a so-called bimetal that has elasticity and bends and expands according to temperature, and the direction in which the tip moves at the high temperature is the photosensitive drum 101 side. It is installed as follows. For this reason, as the temperature becomes higher, the fine fiber cloth 107d is more strongly pressed against the photosensitive drum 101. Under high temperature and high humidity, it is known that a large discharge stress is applied to the photosensitive drum 101 and a lot of discharge products are generated, so that an image flow is likely to occur. However, the support member 107e made of bimetal is Since the fine fiber cloth 107d is more strongly pressed against the photosensitive drum 101 at a high temperature, the cleaning power at a high temperature and high humidity is improved, and an image flow or the like is suppressed. On the other hand, since the pressing force by the support member 107e is small under low temperature and low humidity with low discharge stress, wear of the photosensitive drum 101 due to the fine fiber cloth 107d sliding on the photosensitive drum 101 is reduced. As a result, both high cleaning performance and good image quality are maintained over a long period of time.

  The pressure with which the support member 107e presses the fine fiber cloth 107d against the surface of the photosensitive drum 101 is preferably in the range of 0.5 to 6.0 gf / mm. A more preferable range is 1.0 to 4.0 gf / mm. When the pressing pressure is lower than 0.5 gf / mm, a sufficient rubbing function cannot be exhibited. When the pressing pressure is higher than 6.0 gf / mm, the rubbing with the photosensitive drum is too strong, and the fine fiber cloth and the photosensitive drum. In addition, it causes filming and the like.

  In order to promote uniform rubbing, the fine fiber cloth 107d may be reciprocated in the direction along the axis of the photosensitive drum. The reciprocating movement distance is preferably in the range of 2 mm to 10 mm. When the moving distance is less than 2 mm, the effect is not seen, and when the moving distance is 10 mm or more, the effect is not changed, and the photoreceptor cleaner is increased in size.

  Next, another embodiment of the present invention will be described. However, other embodiments described below are the same as the first embodiment described above except that the structure of the photoconductor cleaner is partially different. Therefore, the following differences from the first embodiment will be described. Other embodiments will be described by focusing on only the points, and among the components of the other embodiments, the same components as those in the first embodiment are denoted by the reference numerals used in the first embodiment. The same reference numerals are used and redundant description is omitted.

  FIG. 3 is a schematic cross-sectional view showing a photoreceptor cleaner in the second embodiment.

  In the photoconductor cleaner 117 in the second embodiment, a rectangular parallelepiped foamed elastic body 117f is attached to the tip portion of the support member 107e, and the fine fiber cloth 107d covers the surface of the foamed elastic body 117f. When the supporting member 107e presses the foamed elastic body 117f, the fine fiber cloth 107d is pressed against the photosensitive drum 101 and rubs against the surface of the photosensitive drum 101. That is, in the second embodiment, an example of the rubbing member according to the present invention is constituted by the fine fiber cloth 107d and the foamed elastic body 117f.

  Examples of the material of the foamed elastic body 117f include foamed urethane, urethane rubber, and silicone rubber.

  By providing the foamed elastic body 117f as described above, the fine fiber cloth 107d is pressed widely and uniformly against the surface of the photosensitive drum 101. As a result, the fine fiber cloth 107d surely wipes unnecessary materials from the surface of the photosensitive drum 101 and collects the unnecessary materials in the above-described aggregates. Therefore, in the two embodiments, high cleaning performance is exhibited. The Rukoto.

  FIG. 4 is a schematic cross-sectional view showing a photoconductor cleaner in the third embodiment.

  In the photoconductor cleaner 127 according to the third embodiment, instead of the support member 107e according to the second embodiment, the metal plate 127g made of stainless steel and the elastic force of the air containing the air function as a spring. An air spring 127h is provided, and the metal plate 127g and the air spring 127h constitute an example of the pressing portion referred to in the present invention.

  The metal plate 127g hardly changes in elastic force with respect to temperature change, but the air spring 127h exhibits a stronger pressing force as the temperature increases due to thermal expansion of the air enclosed inside. As a result, the fine fiber cloth 107d is pressed against the photosensitive drum 101 at a high temperature and weakly at a low temperature, improving the cleaning power at a high temperature and a high humidity, and wear of the photosensitive drum 101 at a low temperature and a low humidity with a low discharge stress. Is reduced. That is, also in the third embodiment, both high cleaning performance and good image quality are maintained over a long period of time.

  Hereinafter, the effects of the present invention will be verified using specific examples and comparative examples.

  First, the photoconductive drum used in common in the examples and comparative examples will be described.

  First, a cylindrical aluminum substrate having an outer diameter of 84 mmφ subjected to a honing treatment was prepared. Next, 100 parts by mass of zirconium compound (trade name: Orgatics ZC540, manufactured by Matsumoto Pharmaceutical Co., Ltd.), 10 parts by mass of silane compound (trade name: A1100, manufactured by Nihon Unicar Co., Ltd.), 400 parts by mass of isopropanol, and butanol 200 parts by mass was mixed to obtain a coating solution for forming the undercoat layer. This coating solution was dip-coated on an aluminum substrate and dried by heating at 150 ° C. for 10 minutes to form an undercoat layer having a thickness of 0.1 μm.

  Next, the Bragg angle (2θ ± 0.2 °) in the Xf-ray diffraction spectrum is 7.5 °, 9.9 °, 12.5 °, 16.3 °, 18.6 °, 25.1 ° and 1 part by mass of hydroxygallium phthalocyanine having a strong diffraction peak at 28.3 °, 1 part by mass of polyvinyl butyral (ESREC BM-S, manufactured by Sekisui Chemical Co., Ltd.), and 100 parts by mass of n-butyl acetate are further mixed. The mixture was dispersed for 1 hour with a vibrating disperser together with the beads to obtain a coating solution for forming a charge generation layer. This coating solution was dip-coated on the undercoat layer and dried by heating at 100 ° C. for 10 minutes to form a charge generation layer having a thickness of about 0.15 μm.

  Next, 2 parts by mass of the charge transport material represented by the following formula (I-1), and 3 parts by mass of a polymer compound having a structural unit represented by the following formula (I-2) (viscosity average molecular weight 39,000) And 20 parts by mass of chlorobenzene were mixed to obtain a coating solution for forming a charge transport layer.

  This coating solution was applied onto the charge generation layer by a dip coating method and heated at 110 ° C. for 40 minutes to form a charge transport layer having a thickness of 20 μm.

  Furthermore, 2.5 parts by mass of a compound represented by the following formula (I-3), 3 parts by mass of Shonor BRL-204 (manufactured by Showa Polymer), hindered phenol antioxidant (AO-80: Asahi Denka) 0.1 parts by mass), 0.2 parts by mass of fluorine graft polymer (ZX007C: manufactured by Fuji Kasei), and 0.1 parts by mass of fluorine coupling agent (KBM-7803: manufactured by Shin-Etsu Chemical) It was dissolved in 5 parts by mass of alcohol and 5 parts by mass of methyl butyl ketone to obtain a coating solution for forming a protective layer. This coating solution was applied onto the charge transport layer by a ring-type dip coating method, air dried at room temperature for 30 minutes, and then cured by heat treatment at 150 ° C. for 1 hour to form a protective layer having a thickness of about 3 μm.

  A photoreceptor drum was obtained by the process described above.

Next, the photoconductor cleaner used in each example and comparative example will be described.
Example 1
In Example 1, the basic configuration of the photoreceptor cleaner 107 shown in FIG. 2 was adopted, and the following components were used as the respective components.
<Brush>
Brush material: conductive nylon, thickness: 2d (about 17 μm), electric resistance: 1.0 × 10 ⁸ Ω, hair leg length: 3.5 mm, density: 120,000 / inch ² , biting into the photoreceptor Amount: about 0.5 mm, peripheral speed: 171 mm / s, rotation direction: reverse rotation with respect to the rotation direction of the photoconductor, brush application bias: + 260V.
<Recovery roll>
Material: Disperse conductive carbon in phenol resin, electrical resistance: 1.0 × 10 ⁸ Ω, flexural modulus: 100 Mpa, wear amount: 2.0 mg, Rockwell hardness (M): 120, bite amount into brush: 1.0 mm, peripheral speed: 201 mm / s, and applied bias: + 660V.
<Scraper>
Material: SUS304, thickness: 80 μm, biting amount: 1.3 mm, free length: 8.0 mm.
<Supporting member>
Material: Bimetal (meeting the standard of TM2 in JIS-C2530), thickness: 0.2 mm M2 (Fuji Metals) was used.
<Fine fiber cloth>
Material: Polyester and nylon, Fiber thickness: 3-5 μm, Thickness: 430 μm Nonwoven WP8085 (manufactured by Japan Vilene Co., Ltd.), biting amount to photoreceptor: 2.0 mm, contact width in photoreceptor rotation direction: 6. Set to 0 mm.
(Example 2)
In Example 2, the basic configuration of the photoconductor cleaner 117 shown in FIG. 3 was adopted, and each component shown below was used as each component.
<Brush>, <Recovery roll>, <Scraper>, <Support member>, <Fine fiber cloth>
Same as Example 1.
<Fine fiber cloth and foamed elastic body>
Material: polyester and nylon, fiber thickness: 3-5 μm: thickness: 430 μm non-woven fabric WP8085 (manufactured by Japan Vilene Co., Ltd.), thickness: 4.0 mm urethane urethane USC (manufactured by Chiyoda Integre Co., Ltd.) The amount of biting into the photoreceptor: 2.0 mm, and the contact length in the photoreceptor process direction: 6.0 mm.
(Comparative Example 1)
A structure having the same configuration as in Example 1 and the material of the support member changed to SUS304 was used as Comparative Example 1.
(Comparative Example 2-1)
A structure having the same configuration as that of Example 2 and the material of the support member was changed to SUS304 was referred to as Comparative Example 2-1.
(Comparative Example 2-2)
Comparative Example 2-2 was obtained by changing the material of the support member to SUS304 and changing the material of the foamed elastic body to soft foamed urethane RR26 (manufactured by INOAC).

  For these examples and comparative examples, the amount of fine fiber cloth biting and pressing pressure were measured.

  FIG. 5 is a diagram showing the performance of the support members in the examples and comparative examples.

  The graph of FIG. 5 shows the temperature dependence of the amount of fine fiber cloth biting with respect to the photosensitive drum. The horizontal axis shows temperature and the vertical axis shows the amount of bite displacement. Using the tip position on the contact surface side of the support member under laboratory conditions (22 ° C, 55RH%) as a reference, the support member is gradually heated or cooled, and the displacement of the tip is measured with a laser displacement meter (manufactured by Keyence Corporation). By doing so, the amount of displacement of the bite amount was obtained. The side closer to the surface of the photosensitive drum is positive, and the side away from the photosensitive drum is negative.

  In Example 1 and Example 2, it was confirmed that the amount of biting increases with increasing temperature and the amount of biting decreases with decreasing temperature. On the other hand, in Comparative Example 1 and Comparative Example 2-1, the amount of biting hardly changes with respect to the temperature change, and the change direction is confirmed to be opposite to the change direction in Example 1 and Example 2. It was.

  FIG. 6 is a diagram illustrating the pressing pressure in the example and the comparative example.

  First, the toner holding member was fixed at a position where the amount of biting with respect to the surface of the image carrier becomes 2.0 mm under laboratory conditions (22 ° C., 55 RH%). Subsequently, the surrounding atmosphere was shifted to a high temperature and high humidity condition (28 ° C., 85 RH%) and a low temperature and low humidity condition (10 ° C., 15 RH%), and the pressing pressure in a sufficiently stable state was measured.

  In both Example 1 and Example 2, the pressing pressure increases under the high temperature and high humidity conditions than under the laboratory conditions, and the pressing pressure decreases under the low temperature and low humidity conditions. On the other hand, in Comparative Example 1, Comparative Example 2-1, and Comparative Example 2-2, the pressing pressure decreases under high temperature and high pressure conditions, and the pressing pressure increases under low temperature and low humidity conditions.

  Using these Examples and Comparative Examples, the image quality and the photoreceptor life were evaluated as described below. This evaluation was performed using a modified machine of DocuCenter Color 500 (Fuji Xerox Co., Ltd.). The toner and developer used in the DocuCenter Color f450 (manufactured by Fuji Xerox Co., Ltd.) products are used, and high temperature and high humidity conditions (28 ° C, 85RH%) and low temperature and low humidity conditions (10 ° C, 15RH%) In this environment, 100,000 image forming cycles were performed. As an image pattern, an average image density of 5% was created by arranging a plurality of patches having a solid density of 100% and having a circumferential length of 9 mm and an axial length of 27 mm on the entire A4 sheet. . After the 100,000 image forming cycles are completed, the image quality evaluation sample of 300% and 20% is printed after being left in the same environment for 8 hours, and the image flow (depression) on the image quality evaluation sample is evaluated. At the same time, filming on the photoreceptor surface and the amount of wear were evaluated. The image flow was evaluated by visual observation at three levels: o: not generated / x: generated at two levels, filming: O: not generated / Δ: generated but no defect was observed in image quality / x: generated at three levels. Further, the photoreceptor surface wear amount was measured by comparing the initial film thickness with the film thickness after 100,000 cycles using an eddy current film thickness measuring device (Fischer Instruments).

  FIG. 7 is a table summarizing the evaluation results under high temperature and high humidity conditions (28 ° C., 85 RH%), and FIG. 8 is a table summarizing the evaluation results under low temperature and low humidity conditions (10 ° C., 15 RH%).

  In Example 1 and Example 2, it was confirmed that image printing can be sufficiently prevented under any conditions and a good print image quality can be obtained. In addition, the occurrence of filming was suppressed, and it was confirmed that high cleaning performance was obtained. Further, it was confirmed that the surface wear amount of the photoreceptor was suppressed to 0.25 μm or less under high temperature and high humidity, and further suppressed to 0.20 μm or less under low temperature and low humidity. It was confirmed that realization was realized. That is, a desired effect is obtained by using a bimetal for the support member.

  In contrast to these examples, in Comparative Example 1 and Comparative Example 2-1, image flow occurred under high-temperature and high-humidity conditions, and under low-temperature and low-humidity, the photoreceptor surface wear amount was as large as 0.35 μm. Show. This is because the scraping property of the discharge product is reduced under high temperature and high humidity conditions due to the change in pressing pressure shown in FIG. 6, and the wear on the surface of the photoreceptor is accelerated by excessive pressing pressure under low temperature and low humidity conditions. Guessed. Further, in Comparative Example 2-2, although the photoreceptor surface wear amount is suppressed to a small value of 0.10 μm or less, image flow and filming occur even under low temperature and low humidity, and cleaning performance Is clearly lacking.

  Thus, the effects of the present invention were verified by specific examples and comparative examples.

  In the above description, a printer is shown as an embodiment of the image forming apparatus of the present invention, but the image forming apparatus of the present invention may be a copier or a facsimile. The printer is a so-called rotary type color printer, but the image forming apparatus of the present invention may be a so-called tandem type color printer or a monochrome printer.

  In the above description, an example of the rubbing member according to the present invention is shown by rubbing with a fine fiber cloth, but the rubbing member according to the present invention is rubbing with foamed urethane or the like. May be.

  In the above description, an example in which one photosensitive cleaner is provided for the photosensitive drum is shown, but the image forming apparatus of the present invention includes a plurality of cleaning devices for one image carrier. It may be provided.

It is a schematic sectional drawing which shows 1st Embodiment of this invention. It is a schematic sectional drawing which shows the photoconductor cleaner in 1st Embodiment. It is a schematic sectional drawing which shows the photoreceptor cleaner in 2nd Embodiment. It is a schematic sectional drawing which shows the photoreceptor cleaner in 3rd Embodiment. It is a figure which shows the performance of the supporting member in an Example and a comparative example. It is a figure which shows the pressing pressure in an Example and a comparative example. It is the table | surface which put together the evaluation result in high temperature, high humidity conditions (28 degreeC, 85RH%). It is the table | surface which put together the evaluation result in low temperature low humidity conditions (10 degreeC, 15RH%).

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Printer 101 Photoconductor drum 102 Charger 103 Exposure part 104 Developing unit 104Y, 104M, 104C, 104K Developer 105 Intermediate transfer belt 106 Primary transfer roll 107, 117, 127 Photoconductor cleaner 107a Brush 107b Recovery roll 107c Scraper 107d Fine Fiber cloth 107e Support member 117f Foam elastic body 127g Metal plate 127h Air spring 108a Internal tray 108b Manual feed tray 108c Transport roll 109 Secondary transfer device 110 Belt cleaner 111 Fixing device 112 Loading tray

Claims (5)

In a cleaning device for cleaning an image carrier on which a toner image is formed,
A rubbing member that is pressed against the image carrier and rubs on the image carrier;
A pressing portion that presses the rubbing member against the image carrier, and at a predetermined high temperature, a pressing portion that presses with a pressing force stronger than a pressing force at a predetermined low temperature lower than the high temperature;
The rubbing member has a cloth made of fine fibers having a diameter of 10 μm or less, and the image carrier is rubbed with the cloth.
Wherein the fabric is, with respect to the image carrier surface state, and are not in surface contact with the rubbing direction has a width,
A cleaning device , comprising: a removing unit that removes an unnecessary object on the image carrier rubbed by the rubbing member by a potential difference from the image carrier .   The cleaning device according to claim 1, wherein the pressing portion includes a bimetal, and the pressing force is generated by the bimetal.   The cleaning device according to claim 1, wherein the pressing portion includes an air spring, and the pressing force is generated by the air spring. The rubbing member has the cloth and a foamed elastic body covered with the cloth, and rubs the image carrier with the cloth.
2. The cleaning apparatus according to claim 1 , wherein the pressing portion presses the rubbing member against the image carrier by pressing the foamed elastic body of the rubbing member with the pressing force . An image carrier on which a toner image is formed and which carries and moves the toner image;
  A charging unit for charging the image carrier;
  An exposure unit that forms an electrostatic latent image by irradiating exposure light onto the image carrier charged by the charger;
  A developing unit that forms a toner image by developing the electrostatic latent image formed by the exposure unit with toner;
  A transfer unit that transfers the toner image formed by the developing unit onto a predetermined transfer object;
  A rubbing member that is pressed against the image carrier after the toner image is transferred by the transfer unit and rubs on the image carrier;
  A pressing portion that presses the rubbing member against the image carrier, and at a predetermined high temperature, a pressing portion that presses with a pressing force stronger than a pressing force at a predetermined low temperature lower than the high temperature;
  The rubbing member has a cloth made of fine fibers having a diameter of 10 μm or less, and the image carrier is rubbed with the cloth.
  The cloth is in surface contact with the image bearing member surface with a width in the rubbing direction,
  An image forming apparatus comprising: a removing unit that removes an unnecessary object on the image carrier rubbed by the rubbing member by a potential difference from the image carrier.

Images