JP5300652B2 - Cleaning device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cleaning device capable of efficiently removing a discharge product from a photoreceptor by rubbing by increasing the number of abrasive particles carried by a brush roller, even when the number of abrasive particles included in developer is small. <P>SOLUTION: The cleaning device 5 brings a cleaning blade 45 into contact with the photoreceptive drum 1, to remove toner remaining even after transfer. A fur brush 53 is arranged on the upstream side of the cleaning blade 45 and rotated while the abrasive particles mixed with the toner are adhered, to polish the surface of the photoreceptive drum and remove the discharge product. Recycling means (51 and 52) recover the abrasive particles and the toner from the brush roller (53) and then, separate the abrasive particles, to readhere them to the brush roller (53). The recycling means have a recovery blade 52 coming into contact with a recovery roller 51, to scrape the abrasive particles and the toner. Projecting and recesses whose ten-point average roughness in the longitudinal direction of the recovery roller is smaller than the average particle size of the toner and larger than the average particle size of the abrasive particles are formed on the surface of the recovery roller 51. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a cleaning device that removes toner containing abrasive particles from the surface of a photoreceptor, and more specifically, even if there are few abrasive particles contained in the toner, the photoreceptor is efficiently rubbed with abrasive particles to produce a discharge product. It relates to a structure that can be removed.

  2. Description of the Related Art Image forming apparatuses that transfer and thermally fix a toner image formed on a photoreceptor directly or indirectly to a recording material via an intermediate transfer member are widely used. The image forming apparatus performs charging of the surface of the photoconductor, formation of a toner image using toner, transfer of the toner image, and cleaning after transfer in a cycle of one rotation of the photoconductor. For cleaning the surface of the photoreceptor, a cleaning blade system in which a rubber blade is brought into contact with the rotating photoreceptor in the counter direction is generally used.

  However, the photosensitive layer on the surface of the photoconductor wears when continuously rubbed with a cleaning blade carrying toner at the tip, so a photoconductor with increased surface hardness and increased wear resistance is practical. (Patent Document 1).

  However, with a photoconductor with improved wear resistance, the discharge product cannot be sufficiently removed with a cleaning blade, and therefore the surface resistance of the photoconductor is reduced and image defects (image flow) are likely to occur in a high humidity environment. Become. For this reason, a proposal has been made that a brush roller that rotates at a high speed is disposed upstream of the cleaning blade, and the photosensitive member is rubbed with a brush roller carrying toner containing abrasive particles to remove discharge products (Patent Document). 2).

  Patent Document 3 discloses an electrostatic brush type cleaning device that removes toner by sliding a conductive brush roller to which a voltage is applied against a photoconductor. Here, a brush roller that rotates at a high speed is disposed upstream of the cleaning blade. Then, a potential gradient is formed in the order of the photoconductor, the brush roller, and the metal roller, the toner collected from the photoconductor is fed forward, and the toner transferred to the metal roller is scraped off by a collection blade that contacts the metal roller.

JP 2001-166520 A JP 2002-182536 A JP 2007-132999 A

  As a result of increasing the surface hardness of the photosensitive layer and further extending the life of the photoreceptor, it is more difficult to remove the discharge products with the existing cleaning devices disclosed in Patent Documents 2 and 3. Further, as a result of increasing the peripheral speed of the photosensitive member in order to increase the number of images formed per unit time, toner adhesion to the photosensitive member and resin film contamination (filming) are likely to occur.

  Therefore, it has been proposed to increase the proportion of abrasive particles contained in the developer and improve the cleaning performance of the existing cleaning device as compared with the past, but as the abrasive particles contained in the developer increase, there are various It has been found that harmful effects occur. That is, the charging performance is deteriorated due to the surface contamination of the charging roller, the recording material slips due to the surface contamination of the transfer roller, and the charging performance of the toner in the developing device is decreased.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a cleaning device capable of efficiently removing a discharge product from a photoreceptor by increasing the number of abrasive particles carried on a brush roller even if the amount of abrasive particles contained in a developer is small. Yes.

  The cleaning device of the present invention includes a brush roller that rotates and rubs the photoconductor to remove abrasive particles and toner from the surface of the photoconductor, and then polishes after collecting the abrasive particles and toner from the brush roller. Recycling means for separating particles and reattaching them to the brush roller is provided.

  In the cleaning device of the present invention, the abrasive particles collected from the brush roller and the abrasive particles are separated from the toner and reattached to the brush roller. For this reason, the brush roller rubs the photoreceptor while holding the abrasive particles that have been transferred from the photoreceptor.

  Therefore, even if there are few abrasive particles contained in the developer, the abrasive particles carried on the brush roller can be increased and the discharge product can be efficiently rubbed and removed from the photoreceptor.

It is explanatory drawing of a structure of the image forming apparatus of this invention. It is explanatory drawing of a structure of a cleaning apparatus. It is explanatory drawing of a structure of the cleaning apparatus of a comparative example. It is explanatory drawing of the surface roughness of the collection | recovery roller surface. FIG. 6 is an explanatory diagram of a relationship between an average particle diameter of toner and a surface roughness of a collecting roller surface. It is explanatory drawing of the relationship between the fiber diameter of a fur brush, and the surface roughness of the collection | recovery roller surface. It is explanatory drawing of the structure of the cleaning apparatus of Example 2. FIG.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the present invention, as long as abrasive particles are more likely to pass through the recovery blade than the contact portion between a general metal roller and a rubber blade, a part or all of the configuration of the embodiment is replaced with the alternative configuration. It can also be implemented in the embodiment.

  Therefore, any cleaning device can be used as long as it is a cleaning device that removes the transfer residual toner from the photoreceptor using a brush roller. Not only an image forming apparatus using a developer mixed with abrasive particles, but also an image forming apparatus of a type in which abrasive particles are directly injected into a developing device, a photoreceptor, a cleaning device, or the like can be used. Intermediate transfer type, recording material conveyance type, direct transfer type, tandem type, single drum type, full color, monochrome, one-component developer, two-component developer, and image forming with a cleaning device using brush rollers Can be implemented in the device.

  In addition, about the general matter regarding the image forming apparatus shown in patent documents 1-3, and a cleaning apparatus, illustration is abbreviate | omitted and the overlapping description is abbreviate | omitted.

<Image forming apparatus>
An image forming apparatus such as a copying machine or a laser beam printer that forms an image using an electrophotographic process basically has an electrophotographic photosensitive member (photosensitive member) generally of a rotating drum type. Also, a charging unit that uniformly charges the surface of the photoconductor to a predetermined polarity and potential, an image exposure unit that forms an electrostatic image on the charging surface of the photoconductor, and a development that develops the electrostatic image as a toner image Means. The image forming apparatus further includes a transfer unit that transfers the image from the photoreceptor surface to the intermediate transfer member or the recording material, and a fixing unit that fixes the toner image transferred to the recording material side as a fixed image. The image forming apparatus further includes a cleaning unit that removes transfer residual toner from the surface of the photoconductor after the toner image is transferred and cleans the photoconductor surface. The recording material fixed by the fixing unit is discharged as an image formed product (copy, print), and the photoconductor cleaned by the cleaning unit is repeatedly used for image formation.

  FIG. 1 is an explanatory diagram of the configuration of the image forming apparatus of the present invention.

  As shown in FIG. 1, the image forming apparatus 100 is a monochrome printer that directly transfers a toner image formed on a photosensitive drum 1 onto a recording material P. Surrounding the photosensitive drum 1, a charging roller 2, an exposure device 9, a developing device 3, a transfer roller 4, a cleaning device 5, and a static elimination exposure device 8 are disposed. The static elimination exposure device 8 linearly exposes the surface of the photosensitive drum 1 to eliminate variations in surface potential remaining after the previous image formation.

  The charging roller 2 is driven to rotate in contact with the rotating photosensitive drum 1, and is applied with an oscillating voltage obtained by superimposing an AC voltage on a DC voltage from the power source D1, so that the surface of the photosensitive drum 1 has a uniform negative polarity. Charge to dark part potential VD. The exposure device 3 scans a laser beam that is ON-OFF modulated in accordance with an image signal obtained by developing image data, and writes an electrostatic image of the image on the surface of the charged photosensitive drum 1. The developing device 4 carries a charged two-component developer on the developing sleeve 15 and slides it on the photosensitive drum 1, transfers toner to the exposed portion of the photosensitive drum 1, and develops the electrostatic image into a toner image.

  The recording material P stored in the recording material cassette 10 is separated one by one by the separation roller 11 and fed to the registration roller 12. The registration roller 12 waits for the recording material P, and sends the recording material P to the transfer portion T1 in synchronization with the toner image on the photosensitive drum 1.

  The transfer roller 4 abuts on the photosensitive drum 1 to form a transfer portion T1. By applying a positive DC voltage to the transfer roller 4, the toner image carried on the photosensitive drum 1 is transferred to the recording material P that passes through the transfer portion T <b> 1. The recording material P to which the toner image has been transferred by the transfer portion T1 is nipped and conveyed while being heated and pressurized by the fixing device 6 to fix the image on the surface.

  The cleaning device 5 removes the transfer residual toner remaining on the surface of the photosensitive drum 1 that has passed through the transfer portion T1. The cleaning device 5 is provided with a conveyance screw 48 for discharging the transfer residual toner, and the collected toner is conveyed by the conveyance screw 48 to the back side of the image forming apparatus 100 perpendicular to the paper surface, and is collected in a collection container 49. It is discharged and collected. With this configuration, the cleaning device 5 is not clogged with residual transfer toner.

<Photosensitive drum>
There are organic photoreceptors mainly composed of organic semiconductors and inorganic photoreceptors mainly composed of inorganic semiconductors. The organic photoreceptor is generally composed of a charge injection blocking layer, a charge generation layer, a charge transport layer and the like on a conductive substrate. Furthermore, in order to improve the durability of the photoreceptor, a material having excellent wear resistance may be provided as a protective layer on the outermost layer. When there is no protective layer, it is necessary to increase the film thickness of the charge transport layer in order to improve the durability performance of the photoreceptor. On the other hand, providing a protective layer makes it possible to achieve both high image quality and high durability.

  Inorganic photoreceptors are those in which an inorganic semiconductor such as selenium, CdS, or α-Si is formed on a conductive substrate. In particular, α-Si has high wear resistance and is not toxic. Used in forming equipment.

  The photosensitive drum 1 is an organic photoreceptor that is coated on an aluminum drum substrate in the order of an undercoat layer, a positive charge injection preventing layer, a charge generation layer, and a surface protective layer. The surface protective layer has improved wear resistance using an electron beam curable resin. Although the photosensitive drum 1 having high wear resistance is advantageous in terms of life, it is difficult to remove discharge products adsorbed on the surface of the photosensitive drum 1, and image flow is likely to occur during startup at high humidity.

<Charging device>
A corona charging method or a contact charging method is generally used as charging means for uniformly charging the surface of the photoreceptor to a predetermined polarity and potential.

  In the corona charging method, a high voltage is applied to a metal wire that is placed in contact with the surface to be charged in a non-contact manner to generate corona discharge, and the surface to be charged is exposed to the discharged charged particles and charged to a predetermined polarity and potential. Let In the corona charging method, ozone and other discharge products that do not contribute to charging due to corona discharge are generated and easily adhere to the photoreceptor.

  In the contact charging method, a predetermined voltage is applied to a conductive charging member (charging member) such as a roller type (charging roller), a fur brush type, a magnetic brush type, a blade type or the like and brought into contact with a surface to be charged. The charged surface is charged to a predetermined polarity and potential. Since the contact charging method directly discharges the surface to be charged, it has lower ozone and lower power consumption than the corona charging method.

  As a charging voltage application method for the charging member, there are a DC charging method in which only a DC voltage is applied and an AC charging method in which an AC voltage is superimposed on the DC voltage. In the DC charging method, the surface to be charged is charged to a voltage obtained by subtracting the discharge threshold Vth from the applied DC voltage value. However, since the discharge threshold Vth varies due to environmental fluctuations, the potential of the surface to be charged is stabilized at a desired value. It is difficult to let Further, the potential of the surface to be charged is likely to change due to the resistance change of the charging member, and the image density may vary.

  The image forming apparatus 100 employs an AC charging method, and applies an AC component having a peak-to-peak voltage Vpp that is equal to or more than twice the discharge threshold Vth to the DC voltage corresponding to the desired dark portion potential VD. The superimposed vibration voltage is applied. This is for the purpose of smoothing the charged potential by the AC component, and the potential of the surface to be charged converges to VD, which is the center of the peak of the AC component, and is hardly affected by disturbances such as the environment. However, in order to perform charging with discharge due to an AC component, discharge products adhere to the photosensitive drum 1 so that the charging roller 2 is evenly applied to the surface of the photosensitive drum 1 during image formation.

<Developing device>
The developing device 4 stirs the two-component developer in the developing container 19 in which the nonmagnetic toner and the magnetic carrier are mixed with the stirring screws 21 and 22 to charge the nonmagnetic toner to the negative polarity and the magnetic carrier to the positive polarity. . The developing sleeve 15 rotating around the fixed magnetic pole magnet 14 carries the two-component developer whose layer thickness is regulated by the regulating blade 18 and rubs it against the photosensitive drum 1 in a spiked state. By applying an oscillating voltage in which an AC voltage is superimposed on a DC voltage from the power source D2 to the developing sleeve 15, the toner is transferred to the exposed portion of the photosensitive drum 1 having a relatively positive polarity, and the electrostatic image is inverted. Developed.

  The developing sleeve 15 has a diameter of 24 mm, the photosensitive drum 1 has a diameter of 80 mm, and the developing sleeve 15 and the photosensitive drum 1 are opposed to each other with a spacing of 300 μm to form a developing portion. The developing sleeve 15 rotates in the width direction at a peripheral speed of 300 mm / sec and the photosensitive drum 1 at a peripheral speed of 150 mm / sec. The charged potential (dark portion potential VD) of the photosensitive drum 1 is -650V, and the exposed bright portion potential is -200V. The oscillating voltage applied to the developing sleeve 15 is obtained by superimposing a DC voltage Vdc of −500 V on a square wave AC voltage having a peak-to-peak voltage Vpp = 2 kV and a frequency of 2 kHz.

  The two-component developer is a mixture of a non-magnetic toner (toner) having a volume average particle diameter of 8 μm and a magnetic carrier having a volume average particle diameter of 50 μm, and the toner concentration is 5% by weight. The toner charge amount was −30 μQ / g as measured by the blow-off method.

  The toner concentration in the developing container 19 is detected by an optical toner concentration sensor (not shown), and the replenishment toner in the toner hopper 20 is replenished by the supply roller 23 so that the toner concentration is kept constant.

  In the two-component developer, silica and strontium titanate are added as external additives. Silica is added for the purpose of improving the fluidity of the two-component developer and stabilizing the toner charge amount. The strontium titanate stays as abrasive particles at the tip of the cleaning blade 45 or adheres to the fur brush 53 to remove discharge products from the surface of the photosensitive drum 1. By removing discharge products generated along with the alternating current discharge of charging, the surface resistance of the photosensitive drum 1 is prevented from being lowered and the occurrence of image flow is prevented. The toner fusion in which the toner is fused to the photosensitive drum 1 by friction with the cleaning blade 45 is also removed by the polishing effect of the abrasive particles.

<Cleaning device>
FIG. 2 is an explanatory diagram of the configuration of the cleaning device.

  In the electrophotographic image forming apparatus, foreign matters such as transfer residual toner remaining on the surface of the photoreceptor after transfer are removed by a cleaning unit. In the image forming apparatus, it is difficult to transfer all the toner images formed on the surface of the photosensitive member to the intermediate transfer member or the recording material, and about 10% of the toner remains on the surface of the photosensitive member after the transfer. Also, external additives released from the toner and powder (paper powder) generated when the recording material comes into contact with the photosensitive member easily escapes from the transfer and adheres to the photosensitive member. For this reason, it is necessary to remove toner, external additives, paper dust, and the like (transfer residual toner) remaining on the surface of the photoreceptor after transfer every time the toner image is transferred.

  The cleaning device 5 is a blade cleaning system that uses a cleaning blade made of an elastic material such as rubber. The blade cleaning system scrapes off the transfer residual toner by bringing the edge of the cleaning blade into contact with the surface of the photosensitive member, and is excellent in the function of removing the transfer residual toner while having a simple configuration and low cost.

  As shown in FIG. 2, the casing 44 of the cleaning device 5 has an opening 44a at a position facing the photosensitive drum 1, and a cleaning blade 45 and a fur brush 53 are arranged in the opening 44a. The cleaning blade 45 abuts one edge 45 a of a rubber blade made of urethane rubber with a thickness of 5 mm in the counter direction with respect to the rotation direction of the photosensitive drum 1. The fur brush 53 rotates in the arrow R5 direction at a peripheral speed of 130% of the rotational speed of the photosensitive drum 1.

  The transfer residual toner generated at the transfer portion (T1: FIG. 1) is scattered by the rotating fur brush 53, and a part thereof adheres to the fur brush 53. The remaining transfer residual toner adheres to the photosensitive drum 1, passes through the fur brush 53, reaches the edge 45 a of the cleaning blade 45, and is scraped off.

  A rake sheet 47 is attached so as to occupy the lower part of the opening 44 a of the casing 44. The rake sheet 47 is a urethane sheet having a thickness of 60 μm. The rake sheet 47 does not cause the transfer residual toner scraped off from the surface of the photosensitive drum 1 by the cleaning blade 45 or the transfer residual toner dropped from the fur brush 53 to fall into the casing 44 and flow backward to the photosensitive drum 1 side.

  The cleaning blade 45 is attached to the attachment plate 50, and the attachment plate 50 is fixed to the upper end position of the casing 44 to form the upper edge of the opening 44a. The casing 44 is supported so as to be tiltable as a whole around the swing shaft 50a, and the contact pressure of the cleaning blade 45 against the photosensitive drum 1 is set by changing the tilt angle.

  A pair of tension springs 41 are disposed on both outer sides of the casing 44 in the longitudinal direction. One end of the tension spring 41 is attached to the casing 44 and the other end is attached to a pedestal 44 b of the frame of the image forming apparatus 100. The pulling force of the tension spring 41 rotates the entire casing 44 around the swing shaft 50a in the direction of the arrow R6 so that the edge 45a of the cleaning blade 45 is brought into contact with the photosensitive drum 1.

  The fur brush 53 comes into contact with the rotating collection roller 51 on the opposite side of the opening 44a to collect the transfer residual toner. The collection roller 51 is formed of a stainless steel pipe having an outer diameter of φ12 mm, and is disposed so that the amount of entry with respect to the fur brush 53 having a diameter of φ20 mm is 1 mm. The collection roller 51 is rotating in the direction of the arrow R6 at a peripheral speed of 110% with respect to the peripheral speed of the fur brush 53. The collection roller 51, the conveying screw 48, and the fur brush 53 are interlocked by a gear mechanism 43, and are driven by the drive motor 42 to rotate integrally.

  Conventionally, the surface of the collection roller 51 has been polished to a mirror surface by a collection blade so that toner and abrasive particles can be almost completely crushed and removed. However, here, in order to constitute the recycling means of the present invention, the optimum roughening condition of the surface is obtained using the glass beads of # 100 to # 1500, and blasting using such glass beads is performed. The surface is roughened.

  A collection blade 52 formed of urethane rubber and having a thickness of 3 mm is in contact with the collection roller 51 in the counter direction. The nip length in the rotation direction at the contact portion between the collection blade 52 and the collection roller 51 is 20 μm.

  Part of the toner that enters the cleaning device 5 from the photosensitive drum 1 adheres to the fur brush 53 and is delivered to the collection roller 51, and then scraped off by the collection blade 52 and falls into the casing 44. The toner adhering to the fur brush 53 rotates with the fur brush 53 and is transferred to the collecting roller 51, and then scraped off by the collecting blade 52.

As the fur brush 53, the same one as that used in the conventional electrostatic cleaning device was diverted. The fur brush 53 is formed by adhering a fiber-raised sheet to the outer peripheral surface of a stainless steel pipe. A fiber in which carbon is dispersed in nylon to impart conductivity and the resistance is adjusted to 1 × 10 ⁸ Ω / cm is used, and the single yarn diameter of the fiber is 27 μm (5D: denier).

  In addition, as another material of the fur body of the fur brush 53, for example, a metal fiber such as stainless steel, or a synthetic fiber such as rayon or PET resin, which is made conductive by adding a conductive substance such as carbon is available. .

  The cleaning device 5 uses a cleaning blade 45 as a cleaning means, and uses a fur brush 53 as a cleaning auxiliary means. The fur brush 53 prevents a large amount of untransferred toner from directly reaching the cleaning blade 45 when a recording material jam occurs in the transfer portion (T1: FIG. 1), thereby preventing a cleaning failure.

  Further, the fur brush 53 holds the toner scraped off by the cleaning blade 45 on the fiber, a part of the toner is reattached to the photosensitive drum 1, and again on the edge 45 a of the cleaning blade 45 by the rotation of the photosensitive drum 1. Supply. By supplying toner, which is powder, between the photosensitive drum 1 and the edge 45a of the cleaning blade 45, the frictional force between the two is reduced, and the cleaning blade 45 is prevented from being turned over. It also has the effect of obtaining cleaning performance.

  That is, the fur brush 53 also functions as a toner buffer unit that holds toner and returns it to the photosensitive drum 1 little by little. Even when an image with a low image ratio continues to be output, the toner returned from the fur brush 53 is supplied to the edge 45a of the cleaning blade 45, so that the toner staying at the edge 45a of the cleaning blade 45 does not need to be exhausted.

<Comparative example>
FIG. 3 is an explanatory diagram of a configuration of a cleaning device of a comparative example.

  In response to increasing demands for lower running costs and higher image quality for image forming apparatuses, there is an increasing tendency to use photosensitive drums with high wear resistance. In photosensitive drums with high wear resistance, discharge products from the charging device that have been removed at the same time that the photosensitive drum has been scraped are likely to remain on the surface of the photosensitive drum, which causes deterioration in cleaning performance and image quality. Flow may occur.

  If the friction coefficient and adhesion force on the surface of the photoreceptor greatly increase due to the adhesion of the discharge product, in the blade cleaning method, vibration, torsional deformation, etc. may occur at the tip of the cleaning blade due to the increase in frictional force, resulting in a decrease in cleaning performance. is there.

  In addition, since the discharge product is ionic, if it adheres to the surface of the photoreceptor, it tends to adsorb moisture in the air, and the surface resistance of the photoreceptor decreases in a high humidity environment. When the surface resistance of the photosensitive member decreases, the charges that form an electrostatic image are likely to diffuse, and image blur called image flow may occur.

  One method for preventing image flow is to avoid moisture adsorption on the surface of the photoreceptor by heating with a heater. However, if a heater is provided on the photoconductor, not only the configuration of the photoconductor becomes complicated, but also temperature control and the like become necessary, the system becomes complicated, and it becomes impossible to cope with downsizing and personalization of the image forming apparatus. Since a certain time is required for the temperature of the heater to rise, the time from warming up to the start of printing (warm-up time) is increased and the power consumption is also increased. In recent years, the melting point of toner has been lowered due to the demand for energy saving. However, when the photosensitive member is heated by a heater, the toner is easily fused to the surface of the photosensitive member.

  Another method for preventing image flow is a method of scraping the discharge product from the surface of the photoreceptor using a developer containing abrasive particles. By supplying abrasive particles from the developing device to the photosensitive drum and holding the abrasive particles on the tip of the cleaning blade or the hair surface of the brush roller, the polishing effect of the discharge products accompanying the rubbing of the photosensitive member can be enhanced. it can.

  As shown in FIG. 3, in the cleaning device 5E of the comparative example, a collection blade 54 is arranged instead of the collection roller 51 and the collection blade 52 shown in FIG. The collection blade 54 is disposed in direct contact with the fur brush 53 and scrapes off the toner excessively attached to the rotating fur brush 53. All of the toner scraped off from the fur brush 53 by the collection blade 54 falls into the casing 44, is carried out of the casing 44 by the conveying screw 48, and is collected in a collection container (49: FIG. 1).

  As shown in FIG. 1, the abrasive particles added to the two-component developer are supplied from the developing device 3 to the photosensitive drum 1 in a state where they are attached to the toner or the abrasive particles alone. Abrasive particles adhering to the toner or abrasive particles adhering directly to the photosensitive drum 1 enter the cleaning device 5 as the photosensitive drum 1 rotates.

  The toner and abrasive particles that have passed through the fur brush 53 while being attached to the photosensitive drum 1 without being captured by the fur brush 53 are scraped off by the cleaning blade 45 and stay at the tip of the cleaning blade 45. In this state, the abrasive particles are rubbed and polished on the photosensitive drum 1, whereby the discharge products attached to the photosensitive drum 1 are removed.

  A part of the abrasive particles staying at the tip of the cleaning blade 45 passes through the cleaning blade 45 and rotates with the photosensitive drum 1. When the toner and abrasive particles staying at the tip of the cleaning blade 45 grow, a part of them falls on the fur brush 53 and another part falls in the casing 44. The toner and abrasive particles that have fallen into the casing 44 are carried out of the casing 44 by the conveying screw 48 and collected in a collection container (49: FIG. 1).

  The toner and abrasive particles falling on the fur brush 53 and captured by the fur brush 53 rub against the photosensitive drum 1 as the fur brush 53 rotates, and the abrasive particles polish the surface of the photosensitive drum 1 and discharge. Remove the product.

  Conventionally, strontium titanate has been used as an external additive added to the developer as such abrasive particles. However, cerium oxide, aluminum oxide, magnesium oxide, chromium oxide, silicon nitride, silicon carbide, germanium oxide, zinc oxide, tin oxide, zirconium oxide, molybdenum oxide, and tungsten oxide can also be used. Strontium oxide, boron oxide, calcium sulfate, barium sulfate, calcium carbonate, magnesium carbonate, aluminum carbonate and the like can also be used.

  In the cleaning device 5E of the comparative example, it is not necessary to include the heater described above, the configuration is simple, and an image forming process corresponding to energy saving is established. However, adding abrasive particles to the developer replenished to the developing device 4 may affect the charging characteristics and durability characteristics of the toner, and may cause a reduction in image density and toner scattering. is there.

  For this reason, it is preferable to reduce the amount of abrasive particles added to the developer as much as possible. For that purpose, it is important to efficiently utilize the abrasive particles. However, in the cleaning device 5E of the comparative example, the supplied abrasive particles are sequentially discarded together with the toner, so that it cannot be said that the abrasive particles are used efficiently.

  Therefore, as shown in FIG. 2, in the cleaning device of Example 1, the recycling means (51, 52) collects abrasive particles and toner from the brush roller (53), and then separates the abrasive particles to remove the brush roller (53). It is reattached to. The recycling means includes a collection roller 51 that rotates and contacts the brush roller to transfer abrasive particles and toner to the surface, and a collection blade 52 that contacts the collection roller 51 and scrapes the abrasive particles and toner. Then, the contact portion between the collection roller 51 and the collection blade 52 blocks the toner while passing through the abrasive particles.

  Since the average particle size of the abrasive particles is smaller than that of the toner, the ten-point average roughness in the longitudinal direction of the recovery roller is smaller than the average particle size of the toner and larger than the average particle size of the abrasive particles on the surface of the recovery roller 51. Unevenness is formed. As a result, the abrasive particles are not scraped off as much as the recovery blade 52 scrapes off the toner. There is a higher possibility that abrasive particles follow the recovery roller and reattach to the brush roller than when a general mirror-finished metal roller is used as the recovery roller in the conventional fur brush cleaning device. As a result, the abrasive particles that adhere to the brush roller and go around increase.

  Further, since the hair roller cross-section of the brush roller is circular, the average curvature radius of the concave and convex recesses in the longitudinal direction of the recovery roller 51 is set to increase the transfer efficiency from the recovery roller 51 to the brush roller. It is larger than the radius of the cross section. Such irregularities are blasted using spherical glass beads having an average particle diameter larger than the diameter of the hair cross section of the brush roller.

<Example 1>
FIG. 4 is an explanatory view of the surface roughness of the collection roller surface. FIG. 5 is an explanatory diagram of the relationship between the average particle diameter of the toner and the surface roughness of the collection roller surface. FIG. 6 is an explanatory diagram of the relationship between the fiber diameter of the fur brush and the surface roughness of the collection roller surface.

  As shown in FIG. 2, in the first embodiment, a toner pool in which abrasive particles and toner temporarily stay is formed at the contact portion between the collection roller 51 and the collection blade 52. In the toner pool, the toner rotates between the moving collection roller 51 surface and the stationary collection blade 52, so that abrasive particles adhering to the toner due to stirring and friction are easily released from the toner. The abrasive particles released from the toner pass through the staying toner and gather at the tip of the collection blade 52, and pass through the collection blade 52 while being constrained by the irregularities on the surface of the collection roller 51. The abrasive particles that have passed through the collection blade 52 come into contact with the fur brush 53 again and adhere as the collection roller 51 rotates. The abrasive particles adhering to the fur brush 53 are polished by rubbing the photosensitive drum 1. Part of the abrasive particles moves from the fur brush 53 to the photosensitive drum 1 and is supplied to the tip of the cleaning blade 45 where the photosensitive drum 1 is polished again.

  With such a configuration, the abrasive particles that have been discarded together with the conventional toner are also separated from the toner by the collecting roller 51 and supplied again to the fur brush 53, so that the use efficiency of the abrasive particles is increased. For this reason, the number of abrasive particles added to the toner can be reduced, and the influence of development characteristics due to an increase in the abrasive particles can be minimized.

  In the first embodiment, the recovery roller 51 is roughened, and the abrasive particles attached to the toner are slipped by the recovery blade 52 in contact with the recovery roller 51. By reattaching the abrasive particles passing through the collecting roller 51 to the fur brush 53, the abrasive particles are recycled to effectively use the abrasive particles.

  In order to improve the reusability of the abrasive particles, it is important how only the abrasive particles are selectively slipped on the collection roller 51 and the toner is not slipped. Therefore, it is necessary to define the relationship between the roughness of the surface of the collection roller 51 and the average particle diameter of the abrasive particles.

  As shown in FIG. 4A, the particle size distribution of normal toner A and abrasive particles was measured. The normal toner A has a normally distributed particle number distribution centered on the average particle diameter Ma, and the abrasive particles have a normally distributed particle number distribution centered on the average particle diameter m. Therefore, for the normal toner A, it is desirable to set the ten-point average roughness Rz between the upper limit value Ma and the lower limit value Mk.

  As shown in FIG. 4B, the particle size distribution of the fine particle toner A and the abrasive particles was measured. The fine particle toner B has a normally distributed particle number distribution centered on the average particle diameter Mb, and the abrasive particles have a normally distributed particle number distribution centered on the average particle diameter m. Therefore, for the fine particle toner B, it is desirable to set the ten-point average roughness Rz between the upper limit value Mb and the lower limit value Mk.

  As shown in FIG. 5, the relationship between the average particle diameter of the toner and the ten-point average roughness Rz of the surface of the collection roller 51 is defined at the contact portion between the collection roller 51 and the collection blade 53. In order to stop the toner that adheres to the collection roller 51 and moves by the collection blade 52, the gap generated between the collection roller 51 and the collection blade 52 needs to be smaller than the particle size of the toner. If the gap is equal to or larger than the particle size of the toner, the toner in the concave / convex depressions on the collection roller 51 will slip out without being caught by the collection blade 51.

  The depth of the unevenness on the surface of the collection roller 51 can be representatively expressed using the ten-point average roughness Rz. Here, σa is the standard deviation of the particle size distribution of normal toner A, and σb is the standard deviation of the particle size distribution of fine toner B.

  The standard deviations σa and σb are obtained by approximating the toner particle size distribution to a normal distribution. In the case of the normal distribution, 99% or more of the particle parameter of the normal toner A is included in the range of the average value Ma ± 3σa shown in FIG. In addition, almost all of the normal toner A can be blocked if it is a gap that can block toner having a particle size of Ma-3σa or more.

  As shown in FIG. 5, the normal toner A can be damped almost completely by setting the ten-point average roughness Rz of the surface of the collecting roller 51 to be smaller than Ma-3σa.

  On the other hand, as a condition for the abrasive particles to pass through at the contact portion between the collection roller 51 and the collection blade 52, the clearance between the collection roller 51 and the collection blade 52 needs to be larger than the particle size of the abrasive particles, contrary to the clogging condition. is there. When the standard deviation of the particle size of the abrasive particles is σk and the average particle size is Mk, 99% or more of the abrasive particles are included in the particle size range of Mk + 3σk or less. Then, by setting the ten-point average roughness Rz on the surface of the collection roller 51 to be larger than Mk + 3σk, most of the abrasive particles can be passed through.

  Therefore, when the average particle size M and the particle size distribution σ of the toner and the abrasive particles are different, an appropriate ten-point average roughness Rz of the collecting roller 51 can be defined from the average particle size M and the standard deviation σ of the toner and the abrasive particles.

In the case of the normal toner A shown in FIG. 4A, by satisfying the relationship of the following equation, only the abrasive particles are slipped through the collection roller 51 while clogging the normal toner A, so that the contact portion with the fur brush 53 is contacted. Abrasive particles can be conveyed.
Mk + 3σk <Rz <Ma-3σa (1)

In the case of the fine particle toner B shown in FIG. 4B, by satisfying the relationship of the following formula, only the abrasive particles are slipped through the collection roller 51 while the fine particle toner B is damped, and the fine toner B is brought into contact with the fur brush 53. Abrasive particles can be conveyed.
Mk + 3σk <Rz <Mb-3σb (2)

  By the way, most of the abrasive particles that have passed through the collection blade 52 are attached to the recesses on the surface of the collection roller 51. For this reason, in order to efficiently transfer the abrasive particles on the surface of the collection roller 51 to the fur brush 53, the tip of the fiber of the fur brush 53 needs to enter the recess on the surface of the collection roller 51. Therefore, a condition for allowing the fiber of the fur brush 53 to enter the recess of the collection roller 51 will be considered.

  Since the tip of the fur brush is cut into a cylindrical shape, the cut surface of the fiber is almost a surface perpendicular to the fiber direction of the fiber.

  As shown in FIG. 6A, when the cut surface of the fiber is perpendicular to the fiber direction, the end of the fiber enters the recess most deeply because the cut surface of the fiber is at 90 ° with respect to the collection roller 51. When standing.

  As shown in FIG. 6B, when the state of FIG. 6A is viewed from the cut surface side of the fiber, if the curvature of the concave portion on the surface of the collection roller 51 is larger than the curvature of the fiber, the fur brush 53 is removed from the collection roller 51. It turns out that it penetrates to the bottom of the concave portion on the surface.

  The shape of the recess on the surface of the collection roller 51 depends on the roughening method. In Example 1, since it is a blast process using spherical glass particles, the curvature of the recesses is determined according to the particle size of the blast particles.

When the fiber single yarn diameter of the fur brush is Df and the particle diameter of the blast particle is Db, the tip of the fur brush 53 efficiently scrapes the abrasive particles from the concave portion of the collection roller 51 by satisfying the relationship of the following formula. Can do. Thereby, the abrasive particles on the collection roller 51 adhere to the fur brush 53 efficiently.
Db> Df (3)

  As shown in Tables 1 to 5 below, in order to verify the relationship of the above formulas (1) to (3), the image forming apparatus 100 is used to measure the ten-point average roughness Rz on the surface of the collection roller 51, the fur brush The image flow test was conducted with 53 single yarn diameters Df being different. The image flow test was performed by intermittently forming 100,000 images in a high-temperature and high-humidity test environment of 30 ° C. and 80% RH and visually confirming the degree of image flow on the output image. The degree of image flow was evaluated in three stages, where no image flow was indicated by ◯, there was image flow at a part of the image, Δ, and there was image flow at the entire image.

  Further, in order to quantify the abrasive particles adhering to the fur brush 53, elemental analysis was performed using a fluorescent X-ray analyzer. Fluorescence X-ray analysis was quantified by directly irradiating the fur brush 53 under various conditions with X-rays using an XGT-5000 manufactured by HORIBA, and measuring the spectral intensity peak values of the elements contained in the abrasive particles. . In Example 1, since strontium titanate was used as the abrasive particles, quantification was performed using the spectral intensity peak value of strontium (Sr).

  Further, in order to confirm the toner slipping state at the contact portion between the collection roller 51 and the collection blade 52, the toner adhesion amount was visually confirmed at a position downstream of the collection blade 52 of the collection roller 51. The presence state of the toner on the collecting roller 51 exhibited a binary behavior depending on conditions such as a ten-point average roughness Rz, and thus was evaluated with two or more stages.

(Experiment 1)
First, the ten-point average roughness Rz was shaken using normal toner A. The normal toner A has an average particle size Ma = 6.0 μm and a standard deviation σa = 1.0 μm. In general toner A, strontium titanate having an average particle size Mk = 0.10 μm and standard deviation σk = 0.01 μm is added as abrasive particles at a ratio of 1.0% by weight, and in addition, a central particle as a fluidity imparting agent is added. Silica with a diameter of 0.02 μm was added. The fiber single yarn diameter Df of the fur brush 53 was set to 27 μm, and the blast particle diameter Db was fixed to 40 μm. The experimental results are shown in Table 1.

  Substituting the above numerical values into equation (1), the 10-point average roughness Rz of the collection roller 51 is preferably in the range of 0.13 μm to 3.0 μm, as shown in FIG. Also in Table 1, no image flow is seen in Examples 1-1, 1-2, 1-3, and 1-4 that fall within this range. In Comparative Example 1-1 in which the ten-point average roughness Rz on the surface of the collection roller 51 is less than 0.13 μm, it is considered that the image flow occurred because the abrasive particles recycled to the fur brush 53 were too few.

  This is supported by the spectral intensity peak value of strontium. If the peak value is 60 or more as in Examples 1-1, 1-2, 1-3, and 1-4, it is estimated that a sufficient amount of abrasive particles is recycled to the fur brush 53 and no image flow occurs. it can.

  This is because if the amount of abrasive particles held on the fur brush 53 is large, the polishing effect of the photosensitive drum 1 by the fur brush 53 is enhanced. In addition to this, the abrasive particles are sufficiently supplied from the fur brush 53 to the photosensitive drum 1 and carried to the tip of the cleaning blade 45, and the polishing effect at the tip of the cleaning blade 45 is enhanced.

  On the other hand, in Comparative Example 1-2 in which the ten-point average roughness Rz on the surface of the collection roller 51 exceeded 3.0 μm, the toner on the collection roller 51 increased and image flow occurred. This is presumably because the toner was not separated at the contact portion between the collection roller 51 and the collection blade 52, and the toner was recycled along with the abrasive particles to the fur brush 53 along with the collection roller 51. The large particle size toner adhering to the fiber of the fur brush 53 reduces the chance of contact between the small particle size abrasive particles adhering to the fiber and the photosensitive drum 1. Further, the toner scraped off by the cleaning blade 45 increases, and the abrasive particles staying at the tip of the cleaning blade 45 decrease. The proportion of abrasive particles that fall together with the toner into the casing 44 and are quickly discharged by the conveying screw 48 increases. By these, the polishing effect by the abrasive particles is hindered.

(Experiment 2)
Next, the ten-point average roughness Rz was shaken using the fine particle toner B. The fine particle toner B has an average particle diameter Mb = 5.0 μm and a standard deviation σb = 1.2 μm. To the fine particle toner B, 1.0% by weight of strontium titanate having an average particle size Mk = 0.20 μm and a standard deviation σk = 0.02 μm is added as abrasive particles, and a central particle is used as a fluidity imparting agent. Silica with a diameter of 0.02 μm was added. The fiber single yarn diameter Df = 27 μm of the fur brush 53 and the particle diameter Db = 40 μm of the blast particles are the same as those in Experiment 1. The experimental results are shown in Table 2.

  Substituting the above numerical values into equation (2), the 10-point average roughness Rz of the surface of the collection roller 51 is preferably in the range of 0.26 μm to 1.40 μm, as shown in FIG. Also in Table 2, no image flow is seen in Examples 1-5 and 1-6 that fall within this range. In Comparative Examples 1-3 and 1-4 in which the ten-point average roughness Rz on the surface of the collecting roller 51 is less than 0.26 μm, it is considered that the image flow is generated because the abrasive particles recycled to the fur brush 53 are too few. It is done. Further, in Comparative Examples 1-5 and 1-6 in which the 10-point average roughness Rz on the surface of the collection roller 51 exceeds 1.40 μm, a large amount of toner passes through the collection blade 52 and adheres to the brush roller 53. As a result, abrasive particles It is considered that image polishing occurred due to the loss of the polishing effect.

(Experiment 3)
Next, as shown in FIG. 6B, the radius of curvature of the concave portion on the surface of the collection roller 51 as viewed from the rotation direction was varied. Using normal toner A, the particle size Db of the blast particles was changed to 15, 20, 27, 35, and 40 μm. The ten-point average roughness Rz = 0.3 μm on the surface of the collection roller 51 and the fiber single yarn diameter Df = 27 μm of the fur brush 53 are common. The experimental results are shown in Table 3.

  If Df = 27 μm is substituted into equation (3), as shown in FIG. 6B, the optimum range of the particle size Db of the blast particles is 27 μm or more, and the curvature radius of the recess is 13.5 μm or more. Also in Table 3, in Example 1-7 where Db = 27 μm, Example 1-8 where Db = 35 μm, and Example 1-9 where Db = 40 μm, no image flows.

  In Comparative Examples 1-7 and 1-8, in which the particle size Db of the blast particles is less than 27 μm, image flow occurred. This is probably because the fur brush 53 does not sufficiently enter the concave portion of the collection roller 51, so that the abrasive particles are not sufficiently transferred to the fur brush 53 and the polishing effect by the abrasive particles is insufficient. This is also supported by the spectral intensity peak value of strontium. In Comparative Examples 1-7 and 1-8, the peak value is less than 60 and the amount of abrasive particles in the fur brush 53 is insufficient.

(Experiment 4)
Next, in the case where the fiber single fiber diameter Df of the fur brush 53 was 35 μm, the particle diameter Db of the blast particles was changed to 15, 20, 27, 35, and 40 μm, as in Experiment 3. The ten-point average roughness Rz = 0.3 μm on the surface of the collection roller 51, and the toner and abrasive particles are the same as in Experiment 3. The experimental results are shown in Table 4.

  If Df = 35 μm is substituted into equation (3), the optimum range of the particle size Db of the blast particles is 35 μm or more, and the curvature radius of the recess is 17.5 μm or more. Also in Table 4, no image flow occurred in Examples 1-10 and 1-11 where Db = 35 μm or more.

  In Comparative Examples 1-9, 1-10, and 1-11 in which the blast particle diameter Db is less than 35 μm, the spectral intensity peak value of strontium is less than 60. Since the fur brush 53 does not sufficiently enter the concave portion of the collection roller 51, the amount of abrasive particles in the fur brush 53 is insufficient, and image flow occurs.

(Experiment 5)
As Comparative Example 1-13, a comparison was made with the case where the rotation of the collection roller 51 was stopped and the collection roller 51 was operated only as a contact member of the fur brush 53. In this case, the toner is not collected by the collection roller 51, and the toner adhering to the fur brush 53 is bounced off as the fur brush 53 comes into contact with the collection roller 51. Therefore, the comparative example shown in FIG. The corresponding result. The experimental results are shown in Table 5.

  In Comparative Example 1-13 that does not have the collection roller 51 and the collection blade 52 formed with irregularities, the spectral intensity peak value of strontium was less than 60, and the abrasive particles on the fur brush 53 were not sufficient, and image flow occurred.

From the above, the following relationship was verified. The ten-point average roughness of the collection roller 51 is Rz, the average particle size of the toner is Mt, the standard deviation of the particle size distribution is σt, the average particle size of the abrasive particles is Mk, the standard deviation of the particle size distribution is σk, and the fur brush 53 The fiber single yarn diameter is Df, and the blast particle diameter is Db. At this time, in the first embodiment, image flow does not occur if the following conditions are satisfied.
Mt + 3σt <Rz <Mk-3σk
Db> Df

  Accordingly, the abrasive particles are separated from the toner on the collection roller 51 more efficiently than when the ten-point average roughness Rz is “Mt <Rz <Mk”, and only the abrasive particles are supplied to the fur brush 53. be able to. Accordingly, the adhesion amount of the abrasive particles on the fur brush 53 is further increased, and the image flow is prevented.

<Example 2>
FIG. 7 is an explanatory diagram of a configuration of the cleaning device according to the second embodiment. The second embodiment is mounted on the image forming apparatus 100 shown in FIG. 1 by replacing the cleaning device 5. The only difference from the first embodiment is that it has a means for applying a voltage to the fur brush 53 and the collection roller 51. Therefore, the same components as those in FIG.

  In the first embodiment, the abrasive particles transferred to the recovery roller 51 are increased to transfer the abrasive particles from the recovery roller 51 to the fur brush 53 due to the concentration difference of the abrasive particles. On the other hand, in the second embodiment, the abrasive particles are electrically transferred from the collection roller 51 to the fur brush 53 in addition to the density difference by utilizing the fact that the abrasive particles are charged by friction with the toner. did.

  As shown in FIG. 7, in the cleaning device 5 </ b> A according to the second embodiment, power supplies D <b> 5 and D <b> 6 are connected to the fur brush 53 and the collection roller 51, respectively. The power source D5 applies a DC voltage of −50V to the fur brush 53. The power source D <b> 6 applies a +100 V DC voltage to the collection roller 51. The fur brush 53 and the collection roller 51 are conductive, and a DC voltage having a polarity opposite to the charging polarity of the toner is applied to at least the collection roller. A DC voltage is applied to at least one of the fur brush 53 and the collection roller 51 so that the collection roller 51 has a potential opposite to the charging polarity of the toner with respect to the fur brush 53.

  When the residual potential of the photosensitive drum 1 was measured on the downstream side of the transfer portion T1 shown in FIG. 1, it was about −100 V at the exposed portion and about −300 V at the non-exposed portion. Further, when the transfer residual toner was collected from the photosensitive drum 1 and the charge amount was measured, it was about −10 μQ / g.

  Since the fur brush 53 to which a DC voltage of −50 V is applied has a positive polarity with respect to the photosensitive drum 1 (about −100 V, −300 V), the transfer residual toner is fur at the contact portion between the fur brush 53 and the photosensitive drum 1. Electrostatic force toward the brush 53 is received. For this reason, the amount of toner to which the abrasive particles are attached moves from the photosensitive drum 1 to the fur brush 53 more than in the first embodiment.

  Further, the collecting roller 51 to which a DC voltage of +100 V is applied has a positive polarity with respect to the fur brush 53 to which a DC voltage of −50 V is applied, so that the collected toner is collected at the contact portion between the fur brush 53 and the collecting roller 51. Electrostatic force toward the roller 51 is received. Therefore, a larger amount of collected toner moves from the fur brush 53 to the collecting roller 51 than in the first embodiment.

  Here, strontium titanate as the abrasive particles has a property of being positively charged by friction with the toner. At the contact portion between the collection roller 51 and the collection blade 52, the collected toner stays and is agitated, and the abrasive particles (strontium titanate) are positively charged by the friction between the toner and the abrasive particles. As in the first embodiment, the abrasive particles that have passed through the contact portion between the collection roller 51 and the collection blade 52 during the agitation process are brought into contact with the fur brush 53 along with the collection roller 51.

  At this time, the fur brush 53 to which a DC voltage of −50 V is applied has a negative polarity with respect to the collection roller 51 to which a DC voltage of +100 V is applied. Therefore, abrasive particles are generated at the contact portion between the fur brush 53 and the collection roller 51. Electrostatic force toward the fur brush 53 is received. For this reason, more abrasive particles than Example 1 move to the fur brush 53 efficiently.

  The abrasive particles carried on the fur brush 53 are subjected to an electrostatic force toward the photosensitive drum 1 at the contact portion between the fur brush 53 and the photosensitive drum, and a part thereof moves to the photosensitive drum 1. It moves to the photosensitive drum 1 more efficiently than the configuration of the first embodiment that relies solely on the physical adhesion of toner and abrasive particles.

  In the configuration of Example 2, the same image flow test as in Example 1 was performed to measure the spectral intensity peak value of strontium in the fur brush 53. As a result, the amount of abrasive particles on the fur brush 53 increased more than in Example 1. It was. The results are shown in Table 6.

  This means that the recycling efficiency of the abrasive particles is further increased by positively controlling the toner and the abrasive particles by electrostatic force. By applying a voltage to the fur brush and the collecting roller using abrasive particles that are charged with a polarity opposite to that of the toner, it is possible to minimize the abrasive particles added to the developer and effectively prevent image flow.

  If the toner has a negative charge and the abrasive particles have a positive charge, it is possible to move the abrasive particles smoothly and efficiently by adopting a configuration such that the voltage of the photoconductor <the applied voltage of the fur brush <the voltage of the collection roller. Can be done.

  In addition, as a material having the same charging characteristics as strontium titanate, a material charged with a charge having a polarity opposite to that of the toner, such as cerium oxide, can be suitably used in the configuration of the second embodiment.

  An image forming apparatus that forms a toner image and transfers it to a recording material.

1 Photosensitive drum 5 Cleaning device 44 Casing 45 Cleaning blade 47 Scoop sheet 48 Conveying screw 51 Recovery roller 52 Recovery blade 53 Fur brush 100 Image forming devices D5 and D6 Power supply

Claims (7)

In a cleaning device provided with a brush roller that rotates and rubs the photoreceptor to remove abrasive particles and toner from the surface of the photoreceptor,
A cleaning apparatus comprising: a recycling unit that collects abrasive particles and toner from the brush roller and then separates the abrasive particles and reattaches them to the brush roller.   The recycling means includes a collection roller that rotates and contacts the brush roller to transfer abrasive particles and toner to the surface, and a collection blade that contacts the collection roller and scrapes the abrasive particles and toner, The cleaning device according to claim 1, wherein the contact portion between the recovery roller and the recovery blade blocks the toner while passing through the abrasive particles. The abrasive particles have an average particle size smaller than that of the toner,
The unevenness having a ten-point average roughness in the longitudinal direction of the collecting roller that is smaller than the average particle size of the toner and larger than the average particle size of the abrasive particles is formed on the surface of the collecting roller. 3. The cleaning device according to 2.   The bristle section of the brush roller is circular, and the unevenness has an average radius of curvature of the recess in the longitudinal direction of the collecting roller that is larger than the radius of the bristle section of the brush roller. 3. The cleaning device according to 3.   5. The cleaning apparatus according to claim 4, wherein the recovery roller is blasted using spherical glass beads having an average particle diameter larger than a diameter of a hair cross section of the brush roller.   The brush roller and the collecting roller are electrically conductive, and a direct current is applied to at least one of the brush roller and the collecting roller so that the collecting roller has a potential opposite to the charging polarity of the toner with respect to the brush roller. The cleaning apparatus according to claim 1, wherein a voltage is applied.   The cleaning apparatus according to claim 1, wherein a cleaning blade is disposed on the downstream side of the brush roller in the rotation direction of the photosensitive member and is in contact with the photosensitive member.

Images