JP2010008462A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cleaning device keeping high cleaning performance for residual toner and a discharge product on an image carrier, and maintaining high print image quality for a long time. <P>SOLUTION: An image forming apparatus is provided with: at least an image carrier; a charging means to charge the surface of the image carrier; an exposing means to expose the image carrier to form a latent image; a developing means to develop the latent image with toner to form a visible image; a transfer means to transfer the visible image onto a transfer medium; and a cleaning means to remove toner remaining on the image carrier. On the downstream side of the transfer means, a toner holding member holding toner and a supporting member supporting the toner holding member are arranged. The toner holding member is pressed onto the image carrier surface while varying a pressing pressure of the toner holding member to the image carrier surface according to a friction factor between the toner holding member and the image carrier surface. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an image forming apparatus using an electrophotographic method, and more particularly to a cleaning device for an image forming apparatus.

  In recent years, so-called electrophotographic image forming apparatuses having a charging unit, an exposure unit, a developing unit, a transfer unit, and a fixing unit have been further increased in speed and life due to the technical progress of each member and system. . As a result, the demand for high-speed compatibility and high reliability of each subsystem is increasing.

  In particular, the electrophotographic photosensitive member used for image writing and the cleaner that removes untransferred toner from the surface of the electrophotographic photosensitive member are subject to a lot of stress due to sliding with the electrophotographic photosensitive member due to scratches, wear, chipping, etc. Image defects are likely to occur, and demands for high-speed compatibility and high reliability are even stronger. On the other hand, there is a strong demand for high image quality, and the toner has been made in a solvent 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. Toners, so-called chemical toners, have been actively developed. As a result, recently, so-called photographic image quality has been obtained.

  Conventionally, a cleaning blade made of an elastic material such as rubber is used as the cleaner, and an edge of one end thereof is brought into contact with the surface of an image carrier such as a photoconductor to remove developer such as toner attached to the surface. Such a configuration is well known. The advantages of this blade cleaning device are that it has a simple configuration and is inexpensive, and can efficiently remove toner and deposits. In this method, it is very important that the contact edge of the cleaning blade is stably brought into contact with the surface of the image carrier with a uniform pressure over a long period of time.

  However, cleaning failure is likely to occur due to toner fusing to the edge, paper dust being caught, edge chipping due to blade material deterioration, and the like. In addition, in the case of a system that uses a toner having a smaller particle diameter than that in the past in order to achieve an improvement in image quality, or in the case of using a so-called spherical toner, the adhesion force of the toner to the surface of the image carrier after transfer is low. Since it becomes extremely high as the Van der Waals force increases, or the rolling friction is reduced due to the spherical shape, it tends to slip out of the blade. When a cleaning blade is used, the contact pressure of the blade Must be set high. As a result, the frictional force between the blade and the surface of the image bearing member is increased, the blade is likely to be turned over, and the surface of the electrophotographic photosensitive member is likely to be increased in wear.

  In such a situation, as a means for removing the toner remaining on the surface of the image carrier or the intermediate transfer member, the knitted fabric is formed on the surface of the core rubber and the sponge rubber layer integrally formed on the core shaft or the surface of the low hardness rubber layer. In addition, a cleaning roller is known in which a covering layer made of a woven fabric or a non-woven fabric is used (see, for example, Patent Document 1). Moreover, the thing of the structure which affixes a nonwoven fabric on the foaming elastic member which mainly aims at the effect of paper dust removal and a cross section becomes a square is known (for example, refer patent document 2).

Japanese Utility Model Publication No. 62-181973 JP 2000-206850 A

  However, the hardness of elastic bodies such as urethane foam and urethane rubber decreases depending on the environment, such as decreasing at high temperature and high humidity and increasing at low temperature and low humidity. Therefore, discharge is generated in a high temperature and high humidity environment where image flow is likely to occur. There is a problem that the scraping performance of the object is insufficient, and there is a problem that the wear of the image carrier is promoted by excessive pressing pressure under low temperature and low humidity. Due to the contact with the agent, the nonwoven fabric itself is worn away, resulting in a problem that the cleaning performance is lowered.

  The present invention has been made in view of the circumstances as described above, and its purpose is to maintain high cleaning performance for residual toner and discharge products on the image carrier and good print image quality over a long period of time. It is to provide a cleaning device that can be used.

  The image forming apparatus of the present invention includes at least an image carrier, a charging unit that charges the surface of the image carrier, an exposure unit that exposes the image carrier to form a latent image, and develops the latent image with toner to make it visible. A toner having a developing unit for forming an image, a transfer unit for transferring a visible image to a transfer medium, and a cleaning unit for removing toner remaining on the image carrier, and holding the toner downstream of the transfer unit A holding member and a supporting member for supporting the toner holding member, and the toner holding member applies pressure to the toner holding member against the surface of the image carrier according to a friction coefficient between the toner holding member and the image carrier surface. It is characterized by being changed and pressed against the surface of the image carrier.

  According to a second aspect of the present invention, in the image forming apparatus, the toner holding member has a cross section formed only by a curve and is fixed on a cam-like base material, and the rotation shaft of the cam-like member is It is characterized by being supported by an elastic body.

  According to a third aspect of the present invention, in the image forming apparatus, the toner holding member is a fiber cloth made of fine fibers having a diameter of 10 μm or less.

  According to a fourth aspect of the present invention, in the image forming apparatus, the image bearing member includes a conductive support and a photosensitive layer formed on the conductive support, and the photosensitive layer is formed from the conductive support. It is characterized by having a charge transporting outermost surface layer containing a resin having a crosslinked structure at the farthest position.

Hereinafter, embodiments of the present invention will be described in detail.
FIG. 1 is a schematic view of an image forming process by an electrophotographic method. Reference numeral 1 denotes an image carrier (photoconductor). First, a portion corresponding to a colored portion of an image formed by the charging device 2 is charged to form a latent image, and a colored toner is applied to the latent image portion by the developing device 3. Is supplied. Next, the toner is transferred to a medium such as paper held on the intermediate transfer belt 7 by the primary transfer device 4, and the toner is fixed on the medium by a fixing unit (not shown) to form an electrophotographic image. Since the toner remains on the surface of the photosensitive member 1 after the transfer, the cleaning device 5 removes the toner, and the photosensitive member 1 is again subjected to the electrophotographic forming process.

  In the present invention, in order to achieve the above-described object, at least the image carrier 1, charging means 2 for charging the surface of the image carrier, and exposure means 6 for exposing the image carrier to form a latent image; Developing means 3 for developing the latent image with toner to form a visible image; transfer means 4 for transferring the visible image to a transfer medium; and cleaning means for removing toner remaining on the image carrier. In the image forming apparatus shown in FIG. 1, the image forming apparatus includes a toner holding member that holds toner on the downstream side of the transfer unit and a support member that supports the toner holding member.

  FIG. 2 is an enlarged view of the image carrier 1 and the cleaning means 5. 2 (a) and 2 (c) are embodiments of the present invention, and (b) and (c) are conventional embodiments. As shown in FIG. 2A, inside the cleaning means, the conductive brush member 15 is in contact with the image carrier 1, and the conductive recovery roller member 16 is in contact with the conductive brush member 15. Further, the scraper 17 is in contact with the conductive recovery roller member 16. The toner remaining on the image carrier 1 is collected by the conductive collection roller member 16 through the conductive brush member 15 and scraped off by the scraper 17.

  In the present invention, a toner holding member 18 a is further provided on the upstream side, and the toner holding member 18 a is held by the support member 19. Here, the toner holding member 18a has an eccentric roll shape in which a fine fiber is pasted on a cam-like base material whose cross section is constituted only by a curve and has a rotation shaft at an eccentric position, and the shaft is elastic. It is supported by a support member 19 made of a body, such as a spring.

  According to the above configuration, when discharge products adhere to the surface of the image carrier 1, the friction between the surface of the image carrier 1 and the toner holding member 18 a increases, and the toner holding member 18 a is attached to the image carrier 1. The surface of the toner holding member 18a having a smaller curvature comes into contact with the image carrier 1, and the pressing pressure is relatively increased. As a result, the removal of the discharge product can be promoted. On the other hand, when the amount of discharge products decreases on the surface of the image carrier 1, the friction between the surface of the image carrier 1 and the toner holding member decreases, and the toner holding member 18a rises due to the restoring force of the support member 19 made of an elastic body. The surface of the toner holding member 18a having the larger curvature comes into contact with the image carrier 1, and the pressing pressure is relatively reduced. As a result, the wear of the surface of the image carrier 1 can be reduced.

  The recovery roll member in the cleaning means is a thermosetting resin and is cured (cross-linked) and formed by heating. Therefore, the post-molding shrinkage hardly occurs, and is very advantageous for the dimensional accuracy required of the recovery roll member. . Examples of the thermosetting resin used in the recovery roll member of the present invention include phenol resin, urea resin, melamine resin, unsaturated polyester, epoxy resin, polyimide resin, etc. Among them, phenol resin has high dimensional accuracy and is molded. It is suitable as a material for use in the recovery roll member of the present invention because it is easy to remove, has excellent surface smoothness of the molded product, and is inexpensive.

  Further, it is preferable that the recovery roll member be an image carrier surface cleaning means having a flexural modulus of JIS K7203 of 700 Kpa or more. If the flexural modulus is less than 700 Kpa, the collecting roll member is bent, and the contact position and the amount of biting with the brush member and the blade cannot be kept constant. Also, using a material with a low flexural modulus, and increasing the wall pressure of the recovery roll member to maintain rigidity, molding shrinkage increases and the desired dimensional accuracy cannot be obtained, but the weight increases and molding time increases. Costs increase due to various problems such as the need for post-processing. Further, the recovery roll member is constantly in contact with the brush member and the blade. Therefore, it is required to be composed of a material that is resistant to wear. When the wear amount exceeds 20 mg according to JIS-K6902, the life of the collecting roll member 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. Moreover, since it becomes possible to form with high dimensional accuracy and the roller is extremely strong against scraping, it is preferable that the Rockwell hardness (M scale) of the recovery roll member in JIS-K7202 is 100 or more.

Further, for the purpose of increasing the rigidity and adjusting the electric resistance to a predetermined range, either one or a plurality of organic fillers or inorganic fillers, and both of the organic fillers and the inorganic fillers are used in the recovery roll member. Plural kinds may be filled. The organic filler mentioned here is carbon black, carbon powder, graphite, magnetic powder, metal oxides such as zinc oxide, tin oxide and 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 oxides, etc. Inorganic fillers include metal powders such as tin, 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 member 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.

  Furthermore, in order to efficiently attract and move fine powder such as toner and paper dust, the brush member disposed in contact with the surface of the image carrier and the collection roll member disposed in contact with the brush member It is preferable to apply a cleaning bias having a potential difference between them. The potential difference between the brush member and the recovery roll member is 100 V or more, preferably 200 V or more. The upper limit is regulated by the bias leak limit, and is preferably suppressed to 650 V or less.

  The so-called transfer residual toner remaining on the image bearing member after the transfer process has a variation in polarity due to the influence of the transfer electric field, and there is even a product that is reversed from the positive electrode to the reverse electrode. Multiple image carrier surface cleaning units, consisting of brush members, recovery roll members, and blades, are installed for each image carrier for the purpose of efficiently removing positive transfer residual toner and reverse transfer residual toner. In addition, a potential difference having a different polarity can be provided for each. The so-called transfer residual toner remaining on the image bearing member after the transfer process has a variation in polarity due to the influence of the transfer electric field, but most of the toner remains as the positive electrode (original charge polarity). . Therefore, a cleaning bias having a potential different from that of the brush member and the recovery roll member with a polarity different from that of the toner is applied to the first image carrier surface cleaning unit to electrostatically attract and move the positive toner occupying most of the transfer residual toner. The next image carrier surface cleaning unit electrostatically adsorbs the toner that has the same polarity as the toner and reverses the polarity by applying a cleaning bias that has a potential difference between the brush member and the recovery roller. It is effective to move.

  The image carrier surface cleaning unit includes an image carrier, a brush member, a recovery roll member, and a blade, and these can be used as one process car cartridge. By using a process car cartridge, maintenance-free operation is realized, and high-quality image formation can be easily repeated simply by replacing the process car cartridge.

  The brush member is formed in a roll shape in which countless fibers are arranged on the outer periphery of the rotating shaft. The brush member is disposed at a position where the tip of the brush slightly bites into the image carrier, and the peripheral surface of the brush member rotates in a direction opposite to the direction of movement of the peripheral surface of the image carrier. The toner and the external additive are peeled off from the surface of the image carrier by contact with each other and are carried to the collecting roll member. The amount of biting between the brush and the image carrier is desirably 0.1 to 2.5 mm, preferably 0.5 to 2.0 mm, and more preferably 0.9 to 1.8 mm.

Specific examples of the material for the brush member include resin fibers such as nylon, acrylic, polyolefin, polyester, etc., by adding conductive powder or an ionic conductive agent to impart conductivity, or for each fiber. A material having a conductive layer formed inside or outside can be used, and the resistance value is preferably 10 ² to 10 ⁹ Ω as a single fiber, more preferably 10 ⁴ to 10 ⁵ , and the thickness of the fiber. Is 30 d (denier) or less, preferably 20 d or less, more preferably 2 d to 10 d, and the density of the fibers is 20,000 / inch ² or more, preferably 30,000 / inch ² or more, more preferably 60,000. it is this / 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 electrical conductivity is uniformly blended in the fiber because of excellent cleaning maintenance.

  The toner collecting roll member is disposed at a position where the outer circumferential surface slightly bites into the outer circumferential surface of the brush member, carries residual toner and external additives attached to the brush member, and is disposed in contact with the toner collecting roll member. The cleaning blade collects residual toner, external additives, and the like carried on the surface.

  A cleaning bias having a potential difference is applied to the brush member and the toner collecting roll member. Residual toner, external additives, and the like scraped from the surface of the image carrier by the mechanical shear force and the potential difference are electrostatically charged. To the toner collecting roll member. A cleaning bias brush having a potential difference applied to the brush member and the toner collecting roll member is first caused by an electrostatic attraction force from the surface of the image carrier to the brush member by an electric field formed between the brush member and the image carrier. It is pulled and removed from the surface of the image carrier. On the other hand, a cleaning bias having an absolute value higher than that of the brush member and having the same polarity as that of the brush member is applied to the toner recovery roll member, so that residual toner and external additives attached to the brush member reattach to the toner recovery roll member. . A cleaning blade or a scraping member is in contact with the toner collection roll member, and toner or the like adhering to the toner collection roll member is removed from the roll member by the cleaning means. This cleaning means is formed from a stainless steel or phosphor bronze metal thin plate 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.

  Next, the toner holding member 18a for cleaning the discharge products and external additives attached to the surface of the photoreceptor 1 will be described. The surface of the toner holding member is made of fine microfibers, and by forming a micro gap between the surface and the contact surface of the photoconductor, the toner remaining on the photoconductor can be held tightly, and thereby the surface of the photoconductor The attached discharge product and external additive 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 any method can be used for the member of the present invention, a nonwoven fabric is desirable in that the strength and density of the fabric is large and the flexibility is high, and the toner can be well held 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 jetted 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 (made 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 (manufactured 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.

  Further, it is desirable that the fine fiber cloth is affixed to a pressing member having elasticity as a backup material, and the surface thereof is pressed against the photosensitive member with a predetermined pressure. Examples of the backup material include foamed urethane, urethane rubber, and silicone rubber. The pressure for pressing the conductive fine fiber against the photoconductor with the backup material 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 photoconductor is too strong and the member itself and the photoconductor are deteriorated. Invitation and induce filming.

  Further, in order to promote uniform rubbing, the fiber cloth member may be reciprocated in the photosensitive member axial direction. The reciprocating movement distance is preferably in the range of 2 mm to 10 mm. If the moving distance is less than 2 mm, the effect is not seen, and if it is 10 mm or more, the effect is not changed and the cleaning unit is increased in size.

Hereinafter, specific embodiments of the present invention will be described with reference to the accompanying drawings. The present invention is not limited to the following examples.
FIG. 1 is a schematic cross-sectional view of an image forming apparatus provided with a cleaning device used in this embodiment. The image carrier 1 of the image forming apparatus is uniformly charged by the charging device 2, and the image carrier 1 is irradiated with light from the exposure device 6 according to the image signal. Then, electrostatic development is formed on the portion of the image carrier 1 irradiated with the light beam, and this electrostatic development is developed by the developing device 3 with toner as a developer and visualized. On the other hand, transfer paper P, which is a recording medium, is loaded on the paper supply device 13, and the transfer paper P in the paper supply device is sent to the secondary transfer roll 10 and the secondary transfer backup roll 9. The visible image carried on the image carrier 1 is transferred to the intermediate transfer belt 7 by the primary transfer device 4 and transferred to the transfer paper P by the secondary transfer roll 10. Then, after the image is fixed by heat and pressure by the fixing device 14, the image is discharged out of the apparatus. The toner remaining on the image carrier 1 is removed by the cleaning device 5 according to the present invention, and the image carrier 1 is again used for image formation.

  2A and 2C are schematic cross-sectional views of the cleaning device of the present invention. As described above, the conductive brush member 15, the conductive recovery roll member 16, and the scraper 17 are attached to the cleaning device of FIG. 2A, and the toner holding member 18a and the support member 19 of the present invention are provided. It is attached. FIG. 2C shows a mode in which the blade 20 is brought into direct contact with the image carrier 1 instead of the conductive brush member 15, the conductive recovery roll member 16 and the scraper 17.

  2B and 2D are schematic cross-sectional views of a cleaning device of a comparative example. FIG. 2B shows a mode in which a cylindrical toner holding member 18b is arranged in place of the toner holding member 18a of the present invention and fixedly brought into contact with the image carrier 1, and FIG. Is a mode in which a disturber brush is brought into contact.

As shown below, each component of the image forming apparatus was produced.
1. Cleaning system 1
<1-a. Brush>
Brush material: Conductive nylon Thickness: 2d (about 17μm)
Electrical resistance: 1.0 × 10 ⁸ Ω
Hair length: 3.5mm
Density: 12,000 pieces / inch ²
Biting into the photoreceptor: approx. 0.5 mm
Peripheral speed: 171 mm / s
Rotation direction: reverse rotation brush applied bias with respect to the rotation direction of the photoconductor: + 260V

<1-b. Collection roll>
Material: Disperse conductive carbon in phenol resin Electrical resistance: 1.0 × 10 ⁸ Ω
Flexural modulus: 100Mpa
Abrasion amount: 2.0mg
Rockwell hardness (M): 120
Biting into the brush: 1.0mm
Peripheral speed: 201mm / s
Applied bias: + 660V

<1-c. Scraper>
Material: SUS304
Thickness: 80μm
Biting amount: 1.3 mm
Free length: 8.0mm

<1-d. Toner Holding Member>
A foamed urethane group using a non-woven fabric made of polyester and nylon (trade name WP8085, manufactured by Japan Vilene Co., Ltd.) having a fiber thickness of 3 to 5 μm and a thickness of 430 μm and having an elliptical cross section (major axis: 18 mm, minor axis: 10 mm) The shaft made of SUS304 and having a shaft diameter of φ5 mm was passed through the focal position on the side far from the image carrier to obtain an eccentric nonwoven fabric roll. A spring member made of SUS304 was attached to both shafts of the shaft as a support member and fixed.

2. Cleaning system 2
<2-a. Blade>
Material: Urethane rubber rebound resilience: 50% (25 ° C, JIS-K6255)
300% modulus: 230 kgf / cm ² (JIS-K6251)
Tear strength: 35 kgf / cm (JIS-K6252)
Permanent elongation: 2.8% (JIS-K6262)
Thickness: 2.0mm
Pressing force: 4.0 gf / mm
Free length: 8.0mm

<2-b. Toner Holding Member>
A foamed urethane group using a non-woven fabric made of polyester and nylon (trade name WP8085, manufactured by Japan Vilene Co., Ltd.) having a fiber thickness of 3 to 5 μm and a thickness of 430 μm and having an elliptical cross section (major axis: 18 mm, minor axis: 10 mm) The shaft was affixed on the material, and a shaft with a shaft diameter of φ5 mm made of SUS304 was passed through the focal position on the side far from the image carrier to obtain an eccentric nonwoven fabric roll. A spring member made of SUS304 was attached to both shafts of the shaft as a support member and fixed.

Next, a photoreceptor of the present invention was produced. Hereinafter, “part” means “part by mass”.
3. Base photoconductor First, a cylindrical aluminum substrate having an outer diameter of 84 mmφ subjected to a honing process was prepared. Next, 100 parts of a zirconium compound (trade name ORGATICS ZC540, manufactured by Matsumoto Pharmaceutical Co., Ltd.), 10 parts of a silane compound (trade name A1100, manufactured by Nihon Unicar Co., Ltd.), 400 parts of isopropanol, and 200 parts of butanol are mixed. A coating solution for forming an undercoat layer was obtained. 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 of hydroxygallium phthalocyanine having a strong diffraction peak at 28.3 °, 1 part of polyvinyl butyral (trade name ESREC BM-S, manufactured by Sekisui Chemical Co., Ltd.) and 100 parts of n-butyl acetate are mixed, and glass beads At the same time, it was dispersed by treating with a paint shaker for 1 hour 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 of a charge transport material represented by the following formula (I-1), 3 parts of a polymer compound having a structural unit represented by the following formula (I-2) (viscosity average molecular weight 39,000), and 20 parts of chlorobenzene was 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. In this way, the photoreceptor in which the undercoat layer, the charge generation layer, and the charge transport layer were formed on the honing-treated aluminum substrate was referred to as a “base photoreceptor”.

<3-a. Photoconductor 1>
2 parts of a compound represented by the following formula (I-3), 3 parts of Resist Top PL4852 (manufactured by Gunei Chemical), 0.1 part of a hindered phenol-based antioxidant (trade name AO-80, manufactured by Asahi Denka) Part, 0.2 part of fluorine graft polymer (trade name ZX007C, manufactured by Fuji Kasei) and 0.1 part of fluorine coupling agent (trade name KBM-7803, manufactured by Shin-Etsu Chemical) are mixed and dissolved in 10 parts of isopropyl alcohol. Thus, a coating solution for forming a protective layer was obtained. This coating solution is applied on the charge transport layer of the base photoreceptor 2 by a ring-type dip coating method, air-dried at room temperature for 30 minutes, and then cured by heat treatment at 135 ° C. for 1 hour to protect the film with a thickness of about 3 μm. A layer was formed. The obtained photoreceptor is referred to as “Photoreceptor 1”.

  The cleaning system 1 and the photoreceptor 1 were combined to obtain Example 1 (FIG. 2a). Comparative Example 1 (FIG. 2b) is a toner holding member that is affixed on a foamed urethane base material: φ17 mm whose cross section is a perfect circle and the shaft passes through the center of the toner holding member. The cleaning system 2 and the photoreceptor 1 were combined to obtain Example 2 (FIG. 2c). The toner holding member was removed, and the following disturber brush was installed as Comparative Example 2 (FIG. 2d).

4). Brush Material: Polypropylene Thickness: 17d
Hair length: 6.5mm
Density: 15,000 / inch ²
Biting into the photoconductor: approx. 1.0 mm
Peripheral speed: 171 mm / s
The rotation was reverse to the rotation direction of the photoreceptor.

  FIG. 3 shows the pressing pressure of the toner holding member of this configuration under high temperature and high humidity conditions (28 ° C., 85 RH%) and low temperature and low humidity conditions (10 ° C., 15 RH%). 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 ambient atmosphere was shifted to the high temperature and high humidity condition and the low temperature and low humidity condition, and the pressing load in a state where the value was sufficiently stable was measured. In Example 1, it turns out by the effect of a spring that it shows the stable pressing pressure, without depending on the environment dependence of a urethane foam base material.

  FIG. 4 shows the relationship between the pressing force of the toner holding member of this configuration and the friction coefficient of the image carrier surface. First, discharge stress was applied to the surface of the image carrier, and image carrier samples having different friction coefficients were prepared. Using a scorotron of Color DocuTech 60V (Fuji Xerox Co., Ltd.), a DC constant current of −900 μA was applied and discharged. The friction coefficient of the surface of the image carrier is measured by using HEIDON tribogear (manufactured by Shinto Kagaku Co., Ltd.), applying a load of 100 g to a 10 mm square WP8085 section and contacting the surface of the image carrier at a speed of 1000 mm / min. Measured by feeding. The measurement was performed in an environment of 22 ° C. and 55 RH%, and the dynamic friction coefficient at that time was μK.

  The toner holding member of the present configuration was placed on the image carrier sample prepared as described above, rotated at a speed of 400 mm / s, and the pressing load of the toner holding member at that time was measured. In Example 1, it was shown that the pressing pressure changes according to the friction coefficient of the surface of the image carrier.

  5 and 6 show the relationship of the coefficient of friction of the photoreceptor surface with respect to the number of rotations in this configuration. Using a modified DocuCenter Color 500 (Fuji Xerox Co., Ltd.), the image forming process was performed 100,000 times in an environment of 10 ° C., 15 RH% or 28 ° C., 85 RH%. As the toner and the developer, those manufactured by DocuCenter Color f450 (manufactured by Fuji Xerox Co., Ltd.) were used. As an image pattern, a halftone image having an average image density of 2.2% was developed on the entire surface of the image carrier. The coefficient of friction of the image carrier surface was measured and compared in the same manner as described above. Particularly in the environment of high temperature and high humidity, the configurations of Examples 1 and 2 can keep the coefficient of friction on the surface of the image carrier lower than the configurations of Comparative Examples 1 and 2. The friction coefficient on the surface of the image carrier has a correlation with the amount of discharge products existing on the surface of the image carrier, and the fact that the friction coefficient is kept low indicates that the discharge products are sufficiently scraped off.

  Tables 1 and 2 below show evaluation results of image quality and photoconductor life in this configuration. After the completion of the image forming cycle, the sample was left in the same environment for 8 hours and then an image quality evaluation sample was printed. The image quality evaluation sample is 300 lines and 20%. The image flow on the image was evaluated, and the surface wear amount and surface state of the photoreceptor were evaluated. Image flow has two levels of “O: not generated / ×: generated”, and filming has three levels of “O: not generated / Δ: generated but no defect is observed in image quality / ×: generated”, cleaning Defects were visually evaluated at two levels: “◯: not generated / ×: generated”. 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). When the film thickness after 100,000 cycles could not be measured due to filming deterioration,-: no data.

  From the results shown in the above table, it was found that in Example 1 and Example 2, good print image quality was obtained under both high temperature and high humidity and low temperature and low humidity conditions, and it was possible to suppress wear particularly under low temperature and low humidity. .

  It has high cleaning performance for residual toner and discharge products on the image carrier, stabilizes the photoreceptor wear rate against environmental load fluctuations, aging, biting and other noise, and provides good print image quality over a long period of time. A cleaning device can be provided that can be maintained across.

1 is a schematic sectional view of an image forming apparatus of the present invention. 2 is an enlarged cross-sectional view of an image carrier 1 and a cleaning unit portion. FIG. 6 is a graph showing the pressing pressure of the toner holding member of the present invention under high temperature and high humidity conditions and low temperature and low humidity conditions. 6 is a graph showing the relationship of the pressing pressure of the toner holding member of the present invention with respect to the coefficient of friction of the image carrier surface. 6 is a graph showing the relationship between the photosensitive member surface friction coefficient and the photosensitive member rotational speed in Example 1 and Comparative Example 1 of the present invention. 6 is a graph showing the relationship of the coefficient of friction of the photoreceptor surface with respect to the photoreceptor rotation speed in Example 2 and Comparative Example 2 of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Image carrier (photoconductor), 2 ... Charging device, 3 ... Developing device, 4 ... Primary transfer device, 5 ... Cleaning device, 6 ... Exposure device (laser generating device), 7 ... Intermediate transfer belt, 9 ... Secondary transfer backup roll, 10 ... secondary transfer roll, 11 ... intermediate transfer belt cleaning device, 13 ... paper feeding device, 14 ... fixing device, 15 ... conductive brush member, 16 ... conductive recovery roll member, 17 ... Scraper, 18a ... toner holding member, 18b ... toner holding member (columnar shape), 19 ... support member, 20 ... blade, 21 ... disturber brush, P ... transfer sheet

Claims (4)

  At least an image carrier, a charging unit that charges the surface of the image carrier, an exposure unit that exposes the image carrier to form a latent image, and a developer that develops the latent image with toner to form a visible image A toner holding member for holding toner on the downstream side of the transfer means, and a transfer means for transferring the visible image onto a transfer medium; and a cleaning means for removing toner remaining on the image carrier. And a support member that supports the toner holding member, and the toner holding member moves to the surface of the image carrier of the toner holding member according to a friction coefficient between the toner holding member and the surface of the image carrier. An image forming apparatus characterized in that the pressure is changed and pressed against the surface of the image carrier.   2. The toner holding member according to claim 1, wherein a cross section of the toner holding member is constituted only by a curve, and the toner holding member is fixed on a cam-like base material, and a rotating shaft of the cam-like member is supported by an elastic body. Item 2. The image forming apparatus according to Item 1.   The image forming apparatus according to claim 1, wherein the toner holding member is a fiber cloth made of fine fibers having a diameter of 10 μm or less. The image carrier includes a conductive support and a photosensitive layer formed on the conductive support, and the photosensitive layer contains a resin having a crosslinked structure at a position farthest from the conductive support. The image forming apparatus according to claim 3, further comprising a charge transporting outermost surface layer.

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