JPH0635257Y2 - Image forming device cleaning device - Google Patents

Description

[Detailed description of the device] [Industrial applications]

The present invention relates to a cleaning device for an image forming apparatus that applies a bias voltage to a conductive bristle brush to clean residual toner on the surface of an image carrier.

[Prior art]

Generally, in an image forming apparatus such as a transfer type electrophotographic copying machine, an image carrier which is a rotating drum type photoconductor having a photoconductive photosensitive layer on its outer peripheral surface is used, and the photosensitive layer is rotated while the image carrier is rotated. An electrostatic latent image is formed on the surface of the sheet, the image is developed with toner, and the obtained toner image is transferred to a recording sheet. After the transfer is completed, the outer peripheral surface of the image carrier is separated and cleaned by the cleaning device to remove the residual toner, and an electrostatic latent image is formed again, and a new image is transferred. In recent years, as a method for removing the residual toner adhering to the outer peripheral surface of the image bearing member, a conductive bristle brush is charged with a polarity opposite to that of the residual toner, and the outer peripheral surface of the image bearing member is rubbed to remove static electricity. BACKGROUND OF THE INVENTION Cleaning devices have been used that remove residual toner by the use of an electric attraction force and a scraping force of a brush. A cleaning device that removes residual toner by rubbing the surface of the image bearing member with a bristle brush to which a bias voltage is applied is disclosed in
42-16590 discloses a basic method of applying a bias voltage to a bristle brush. Then, in JP-B-49-20227, in order to collect the toner adsorbed on the bristle brush, a roller to which a bias voltage is applied is brought into contact with the bristle brush to collect the toner, and the toner attached to the roller is bladed. The method of scraping with is disclosed. Japanese Patent Publication No. 56-40349 discloses a method of forming a bristle body of a brush with conductive fibers. After that, the results of various studies were disclosed, such as the material of the bristle constituting the conductive bristle brush, the implantation density, the resistance of the bristle, the voltage value applied to the conductive bristle brush, and the control method thereof.

[Problems to be solved by the device]

However, in such a cleaning device that removes the residual toner from the surface of the image carrier with the conductive hair brush, the toner once collected from the image carrier may be separated and scattered from the both ends of the conductive hair brush. . The scattered toner redeposits near both ends of the image carrier surface to cause cleaning failure, and mixes with the bearing part that hangs the conductive bristle brush to wear the bearing part and stain peripheral equipment. It had a defect that it was caused. The present invention has been made in view of the above-mentioned drawbacks of the prior art, and a shielding member for preventing toner scattering is provided at both ends of the conductive bristle brush to prevent contamination and wear of peripheral devices and a stable cleaning effect. It is an object of the present invention to provide a cleaning device in an image forming apparatus having the above.

[Means for solving problems]

The purpose is to apply a bias voltage to the conductive bristle brush,
The toner remaining on the surface of the image carrier is removed by rubbing the image carrier, and a bias voltage is applied to the conductive roller in contact with the conductive hair brush to collect the toner from the conductive hair brush. In the cleaning device of the image forming apparatus, the outer diameter is equal to or smaller than the outer diameter of the conductive bristle brush between both side end portions of the conductive bristle brush and both bearing portions of the side plate on which the conductive bristle brush is mounted. This is achieved by a cleaning device for an image forming apparatus, which is filled with an elastic member within this range and fixed to the shaft of the conductive bristle brush.

【Example】

Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings of FIGS. 1 to 4. First, the general functions of the multicolor image forming apparatus having the cleaning device of the present invention will be described with reference to FIG. In FIG. 2, A is a reading unit, B is a writing unit, C is an image forming unit, and D is a paper feeding unit. In the reading unit A, 1 is a platen glass,
The original 2 is placed on the platen glass 1. Manuscript 2
Is illuminated by fluorescent lights 5 and 6 provided on a carriage 4 moving on a slide rail 3. The movable mirror unit 8 is provided with mirrors 9a and 9b, moves on the slide rail 3, and in combination with the first mirror 7 provided on the carriage 4, the optical image of the original 2 on the platen glass 1 is lensed. Lead to the reading unit 20. The carriage 4 and the movable mirror unit 8 are a pulley 1 driven by a stepping motor 10 via a wire 15.
1,12,13,14 are driven in the same direction at speeds of V and 1 / 2V, respectively. Standard white plates 16 and 17 are provided on the back surfaces of both ends of the platen glass 1 so that a standard white signal can be obtained before and / or after the scanning of the original document is started. The lens reading unit 20 includes a lens 21, a prism 22, a first reading substrate 24, a red channel (hereinafter referred to as R-ch) CCD 25, a second reading substrate 26, and a cyan channel (hereinafter referred to as C-ch) CCD 27. The original light image transmitted by the first mirror 7, the mirror 9a, and the mirror 9b is focused by the lens 21, and the R-ch CCD 25 provided on the first reading substrate 24 and the C provided on the second reading substrate 26. An image is formed on the light-receiving surface of the −ch CCD27. The fluorescent lamps 5 and 6 are commercially available warm white fluorescent lamps for preventing the emphasis and attenuation of a specific color based on the light source when reading a multicolor original, and are also lit by a high frequency power source of 40khz to prevent flicker, It is kept warm by a heater using a posistor to keep the tube wall at a constant temperature or to promote warm-up. The image signals output from the R-ch CCD25 and C-ch CCD27 are processed by a signal processing unit. In the signal processing unit, color signals that are color-separated according to the color of the toner, which will be described later, are output and input to the writing unit B. In the writing unit B, the laser beam generated by the semiconductor laser is rotationally scanned by the polygon mirror 32 rotated by the drive motor 30, the optical path is bent by the reflecting mirror 37 through the Fθ lens 36, and the image carrier 40 is formed. A bright line is formed by being projected onto the surface of the photosensitive drum. When the scanning is started, the beam is detected by the index sensor, and the modulation of the beam by the first color signal is started. The modulated beam scans the image carrier 40 that has been uniformly charged in advance by the charger 41. A latent image corresponding to the first color is formed on the surface of the image carrier by the main scanning by the laser beam and the sub-scanning by the rotation of the image carrier 40. This latent image is, for example, a developing device 43 loaded with red toner.
To develop a red toner image on the surface of the image carrier. The obtained toner image, while being held on the surface of the image carrier, passes under the cleaning device 70 which is separated and retracted from the surface of the image carrier, and enters the next copy cycle. The image carrier 40 is uniformly charged by the charger 41. Then, the second color signal output from the signal processing unit is input to the writing unit B, and writing is performed on the surface of the image carrier to form a latent image in the same manner as in the case of the first color signal. . This latent image is developed by the developing device 44 loaded with the second color, for example, blue toner. This blue toner image is formed on the already formed red toner image on the surface of the image carrier. Reference numeral 45 denotes a developing device having a black toner, which forms a black toner image on the surface of the image carrier based on the control signal generated by the signal processing section. AC and DC bias voltages are applied to the sleeves of the developing units 43, 44, and 45, jumping development is performed by a two-component developer, and development is performed in a non-contact manner with the grounded image carrier 40. The toner image based on the first color signal, the toner image based on the second color signal, and the toner image developed based on the black toner image, which are developed in this manner, are superposed on each other. It is transferred onto the recording paper 61 which is a transfer body sent by the feeding belt 62 and the feeding roller 63. The recording paper on which the toner image has been transferred is separated from the image carrier by the separating electrode 51 and is further conveyed to the fixing device 53 to be fixed and a multicolor hard copy is obtained. Thus, the cleaning device 70 shown in FIG. 3 acts on the image carrier 40 that has completed the transfer to remove the unnecessary toner remaining on the peripheral surface. FIG. 3 is a sectional view of a cleaning device according to the present invention. The cleaning device 70 includes a conductive bristle brush 71 and a collecting roller.
72, a blade 73, a toner suction means 74, etc. are provided inside the frame 75, a cleaning means 80, a potential control means 85 on the surface of the image carrier located upstream of the conductive bristle brush 71, and this cleaning means. A contact / release means 81 for pressing and releasing 80 onto the image carrier 40 and a drive means 82 for driving each cleaning member in the cleaning means 80. The cleaning unit 80 is controlled by the contact / release unit 81 into an operating state in which the cleaning unit 80 is in pressure contact with the image carrier 40 and an operating state in which contact is released from the image carrier 40. The potential control means 85 for controlling the surface potential of the image carrier 40 is composed of a charger 86 which is a charge giving member and an exposure lamp 87. The charger 86 is a corotron or a scoroton, and is installed on the upstream side of the conductive bristle brush 71 so as to face the photosensitive surface of the image carrier 40. The exposure lamp 87 is a cold cathode tube with an output of 8W. The diameter of the tube is
The effective length is 6.5 mm, which is equal to or larger than the photosensitive width of the image carrier 40. The exposure lamp 87 is installed at a position close to the downstream side of the charger 86 and 3 mm away from the photosensitive surface of the image carrier 40. The conductive bristle brush 71 is a cylindrical brush in which a conductive bristle 78 and a base cloth are connected to a conductive pipe such as aluminum by a conductive adhesive. The conductive bristle body 78 is woven into the base cloth by a so-called W weave so that the contact portion with the conductive pipe is increased. The planting density of the conductive bristles 78 for the pipe is 100,000 to 200,000.
Filament / in ² . The conductive hair 78 is made of conductive rayon “RecGR” or “RecA”.
R ”(both manufactured by Unitika). Conductive rayon "RecGR" has a fiber specific resistance of 10 ⁸ to 10 ⁹ Ωcm
“RecAR” has a fiber specific resistance of 10 ⁷ to 10 ⁸ Ωcm. The conductive bristle brush of this embodiment has a length of 10 mm and a thickness of 5-6.
Denier conductive hairs were used. FIG. 4 shows a method for measuring the fiber specific resistance. In Figure 4
90 is a fiber specific resistance measuring circuit, P and Q are electrodes, 91 is a measured fiber, 92 is a 500V voltage power source, and 93 is an ammeter. The specific resistance of the measured fiber 91 is measured as follows. First, the filament P to be measured 91 is connected to the electrodes P and Q. The distance 1 between both electrodes is 10 cm. The voltage power supply 92 applies a voltage of 500 V between the electrodes P and Q, and the current value I ₀ flowing at that time is read from the ammeter 93. Specific resistance of the measured fiber 91 ρ
Is calculated from the following equation. ρ = 500 / I ₀ · S / l Note that S is the total cross-sectional area of the measured fiber 91 and is the product of the fiber thickness and the number of fibers. The conductive bristle brush 71 is installed at a position separated from the separation electrode 51 on the downstream side in the rotation direction of the image carrier in a state of being pressed against the image carrier. This pressed state is a state in which the conductive bristle brush 71 and the image carrier 40 bite into each other by 2 mm in the mutual overlapping amount in the radial direction. A bias voltage of DC 200 V is applied to the conductive bristle brush 71 by the first bias voltage power supply 76. The collecting roller 72 is a conductive metal roller. The collecting roller 72 is installed in a pressure contact state with the brush at a position separated from the pressure contact portion between the conductive bristle brush 71 and the image carrier 40 to the downstream side in the rotation direction of the brush. This pressed state is a state in which the collecting roller 72 and the conductive bristle brush 71 bite by 2 to 4 mm in the mutual overlapping amount in the radial direction. A bias voltage of 400 V to 600 V DC is applied to the recovery roller 72 by the second bias voltage power supply 77. The blade 73 is an elastic plate made of hard urethane rubber having a thickness of 0.5 mm. The blade 73 is pressed against the entire length of the collecting roller 72 in the longitudinal direction to scrape off the toner from the surface of the roller. The toner suction unit 74 includes an electric suction fan 741 and a filter 742. The suction opening of the toner suction means 74 is provided so as to face a downstream side portion in the rotation direction of the brush 71 in the vicinity of the pressure contact portion between the conductive bristle brush 71 and the recovery roller 72. The conveying screw 79 is provided near the lower part of the blade 73, and conveys the toner scraped off from the collecting roller 72 to a toner collecting tank (not shown). The pressing means / release means 81 of the cleaning means 80 to the image carrier 40 is an eccentric cam 811 fixed to the drive shaft 83.
And spring 812. Eccentric cam 811
And the frame 75 of the cleaning means 80 is always spring 812.
It is pressed by a spring and is pressed against the image carrier 40 by the rotation of the eccentric cam 811 by the conductive bristle brush 71 to perform a pressing operation and / or a deactivating operation. Conductive bristle brush 71 and recovery roller in the cleaning means 80
72 is rotated by a belt drive by drive means 82 outside the frame 75. While the cleaning unit 80 is deactivated from the image carrier 40 and retracted, the multicolor toner image completed after a plurality of exposures and developments is transferred to the recording paper in the transfer process. To be done. After the transfer step is completed, the residual toner that has not been transferred and has adhered to the outer peripheral surface of the image carrier 40 reaches the facing position of the cleaning unit 80 according to the rotation of the image carrier 40 in the direction of the arrow and adheres here. Are removed. The surface of the image carrier 40 and the adhered toner are first detected by the potential control means 85.
The charging device 86 reaches a position opposite to the charging device 86 and is charged by the charging device 86. By this charging, the adhered toner uniformly has a toner layer potential close to a saturation value, and the surface portion of the image carrier 40 has a potential difference of 300 V to 400 V from the potential before the charging.
The charged state is increased to some extent. Then, the image carrier 40 rotates and receives the irradiation of the exposure lamp 87 together with the adhered toner. By the irradiation of the exposure lamp 87, the photosensitive layer on the surface of the image carrier 40 receives light, and the surface potential of the light receiving portion is lowered. The adhered toner which is still charged and the image carrier whose potential has been lowered reach the position facing the conductive bristle brush 71. Immediately before this, the conductive bristle brush 71 is pressed against the surface of the image carrier 40 by the action of the pressing / releasing means 81, and slides and removes the adhered toner that has reached its facing position. The linear velocity of the outer peripheral surface of the image carrier 40 at this time is 200 mm / se.
c. The linear velocities of the conductive bristle brush 71 and the image carrier 40 are equal and the directions of rotation are opposite. Therefore, the toner adhered on the image carrier 40 is rubbed by the conductive bristle brush 71 at a rub speed of 400 mm / sec. The conductive bristle 78 of the conductive bristle brush 71 is applied with a bias voltage of DC 200V by the first bias voltage power supply 76,
It is charged to the opposite polarity to the adhered toner. The conductive hair body 78 applies electrostatic attraction to the adhered toner to adsorb the toner to the conductive hair body and remove it from the outer peripheral surface of the image carrier 40. The toner adsorbed on the conductive bristle body 78 of the conductive bristle brush 71 is then collected by the collecting roller 72 that rotates while being pressed against the conductive bristle brush 71. The linear velocities of the conductive bristle brush 71 and the collecting roller 72 in the vicinity of the outer peripheral surfaces of both are equal, but the rotating directions are opposite. Therefore, the collection roller 72 rubs the attracted toner of the conductive bristle brush 71 at a rub speed of 400 mm / sec. The recovery roller 72 is a second bias voltage power supply.
A bias voltage of 400 V to 600 V DC is applied by the 77 and the toner is charged in the opposite polarity to the toner. Collection roller
72 is a conductive bristle body for the toner in the conductive bristle brush 71.
The electrostatic attraction, which is stronger than the adsorption force of 78, is applied to collect the toner. Then, the toner collected by the collecting roller 72 is scraped off from the peripheral surface of the roller by the blade 73 and drops onto the conveying screw 79. On the other hand, part of the toner that has entered between the bristles of the conductive bristle brush 71 is not collected by the collection roller 72 and remains on the conductive bristle brush 71. The conductive bristle body 78 is released from the pressing of the collecting roller 72 at the downstream side in the rotation direction of the brush near the contact portion between the conductive bristle brush 71 and the collecting roller 72, and the fluffed state returns to the napped state. Due to the centrifugal force when returning to the napped state, the uncollected toner is separated from the conductive bristle brush 71 and scattered in the air. The scattered toner is a toner suction means provided with a suction opening in the vicinity of the toner releasing portion.
It is sucked and collected by 74. FIG. 1 is an upper partial sectional view in the vicinity of a conductive bristle brush showing a mounting state of a shielding member according to the present invention. In the figure, 95 and 96 are shielding members, 97 and 98 are bearings, 711
Is a rotating shaft of the conductive bristle brush 71, 721 is a rotating shaft of the collecting roller 72, and 751 and 752 are side plates of the frame 75. The shielding members 95 and 96 are made of elastic members such as sponge and rubber. This shielding member has a shaft escape hole at its center,
The cylindrical body has an outer diameter equal to or less than the outer diameter of the conductive bristle brush 71, and a length equal to or less than the distance from the side end surface of the conductive bristle brush to the end surface of the bearing. A thin plate-shaped low friction member 95 such as polytetrafluoroethylene or polyethylene terephthalate is provided on an end surface portion of the shielding members 95 and 96 which are opposed to the side end surface of the conductive bristle brush 71.
1,961 can be attached. The shielding member 95 fills the space between the conductive bristle brush 71 and the bearing 97, and the shielding member 96 also fills the space between the conductive bristle brush 71 and the bearing 98.

[Effect of device]

In the cleaning device of the image forming apparatus of the present invention, since the shielding member formed of the elastic member is provided between the both ends of the conductive bristle brush and the bearing, the length of the conductive bristle brush in the axial direction is image-carried. It has become possible to shorten the width of the body to almost the same as the effective width for image formation. Further, it has become possible to prevent the toner from coming off and scattering from both sides of the conductive bristle brush to prevent the peripheral equipment inside the machine from being soiled. Further, it is possible to prevent the toner from entering the bearing portion, and the life of the bearing is extended. Further, it has become possible to prevent defective cleaning of the portions corresponding to the vicinity of both sides of the conductive bristle brush.

[Brief description of drawings]

FIG. 1 is an upper partial sectional view of a cleaning device showing an embodiment of the present invention, FIG. 2 is a block diagram of a multicolor image forming device, and FIG.
FIG. 4 is a sectional view of the cleaning device, and FIG. 4 is a circuit diagram showing a method for measuring the fiber specific resistance. 40 ... Image carrier, 50 ... Transfer electrode 51 ... Separation electrode, 70 ... Cleaning device 71 ... Conductive bristle brush 72 ... Collection roller, 73 ... Blade 74 ... Toner suction means 75 ... Frame Body 76 …… First bias voltage power supply 77 …… Second bias voltage power supply 78 …… Conductive bristle, 79 …… Conveying screw 80 …… Cleaning means 81 …… Pressing / release means 82 …… Driving means, 85… … Potential control means 86 …… Charger (charge giving member) 87 …… Exposure lamp, 95,96 …… Shielding member 97,98 …… Bearing, 711 …… Rotating shaft 751,752 …… Side plate 951,961 …… Sheet plate low friction Member A ... reading unit B ... writing unit C ... image forming unit, D ... paper feeding unit

Claims (1)

[Scope of utility model registration request] 1. A bias voltage is applied to a conductive bristle brush,
The toner remaining on the surface of the image carrier is removed by rubbing the image carrier, and a bias voltage is applied to the conductive roller in contact with the conductive hair brush to collect the toner from the conductive hair brush. In a cleaning device of an image forming apparatus, an outer diameter is equal to an outer diameter of the conductive bristle brush between both side end portions of the conductive bristle brush and both bearing portions of a side plate on which the conductive bristle brush is mounted. Alternatively, the cleaning device of the image forming apparatus is characterized in that it is filled with an elastic member within the range and the elastic member is fixed to the shaft of the conductive bristle brush.