Electrophotography – Cleaning of imaging surface – Having handling of removed material
Reexamination Certificate
2000-02-10
2001-06-19
Grimloy, Arthur T. (Department: 2852)
Electrophotography
Cleaning of imaging surface
Having handling of removed material
C399S123000, C399S351000
Reexamination Certificate
active
06249665
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an image forming apparatus, and more particularly to improvement of a cleaner for removing toner remaining on the surface of an image bearing body after transfer of a toner image.
Conventionally, in an image forming apparatus such as an electronic photography copying machine, a cleaner having a cleaning blade has been used to remove developing agent not transferred but remaining on the surface of an image bearing body, as disclosed in Jpn. Pat. Appln. KOKOKU Publication No. 63-23552.
Further, there is well known an image forming apparatus which is provided with a magnet member for forcibly attracting waste toner remaining on the image bearing body scraped by a cleaning blade. As a method for removing toner from the roller-shaped magnet member, a method in which a scraper-like toner scraping member is disposed to be in contact with the magnet roller and a method in which a portion of a belt-like sheet member located near the image bearing body brought into contact with the magnet, the end portion of the sheet is separated from magnetic body so as to remove toner have been known.
The remaining toner kept on the surface of the image bearing body in the cleaner by the cleaning blade comes to have a higher packing density compared to ordinary toner if accumulated thereon. Therefore, if the packing density of the accumulated remaining toner increases extremely, a cleaning limit of the cleaning blade is exceeded so that a cleaning fault occurs. Alternatively, a blade edge is damaged by an increase of load so that the aging is accelerated. As a result, the cleaning limit value is lowered thereby leading to such cleaning fault.
Conventionally, to reduce this toner accumulating quantity, a paddle-like rotating body or roll-like magnet is provided to relax the toner pressure. However, because if such a member is provided, the toner scraping member comes into a contact with a rotating roller or paddle, flip sound or friction noise occurs or unnecessary vibration occurs.
Further, because the elastic sheet-like toner separating member vibrates in an enclosed space of the cleaner, gas in the cleaner is discharged out thereof thereby leading to dissipation of toner. Further, the scraping member or paddle or magnet is worn during a copy service life so that removal of toner becomes unequal. As a result, toner collection is partially made difficult so that the cleaning fault is generated.
BRIEF SUMMARY OF THE INVENTION
An object of the present invention is to provide an image forming apparatus capable of removing and collecting developing agent remaining on the surface of an image bearing body effectively without generating friction noise or vibration.
Another object of the present invention is to provide an image forming apparatus capable of removing and collecting developing agent remaining on the surface of the image bearing body effectively without dissipating in the apparatus.
To achieve the above object, according to an aspect of the present invention, there is provided an image forming apparatus comprising a developer for developing a static latent image on an image bearing body using developing agent, a transfer unit for transferring a developed developing agent image on a transfer member and a cleaner disposed so as to be in a sliding contact with the surface of the image bearing body for removing developing agent remaining on the image bearing body after the transferring, the cleaner including a cleaning member for removing developing agent remaining on the image bearing body from the image bearing body, a rotating paddle having a developing agent conveying face for conveying developing agent removed from the image bearing body by the cleaning member upward from a portion near the image bearing body while rotating, and a developing agent scraping member whose tip is in contact with the developing agent conveying face of the rotating paddle for scraping developing agent adhering to the rotating paddle, wherein assuming that an angle between a tangent line of the developing agent conveying face of the rotating paddle and a tangent line of the image bearing body is ∠&thgr;1 at a position in which the tip of the rotating paddle approaches the image bearing body most and the ∠&thgr;1 in the center of the rotating paddle is ∠&thgr;1A while the ∠&thgr;1 at the tip of the rotating paddle is ∠&thgr;1B, the rotating paddle has a curved shape so as to satisfy an inequality of ∠&thgr;1A>∠&thgr;1B.
Further, according to another aspect of the present invention, there is provided an image forming apparatus comprising a developer for developing a static latent image on an image bearing body using developing agent, a transfer unit for transferring a developed developing agent image on a transfer member and a cleaner disposed so as to be in a sliding contact with the surface of the image bearing body for removing developing agent remaining on the image bearing body after the transferring, the cleaner including a cleaning member for removing developing agent remaining on the image bearing body from the image bearing body, a rotating paddle having a developing agent conveying face for conveying developing agent removed from the image bearing body by the cleaning member upward from a portion near the image bearing body while rotating, a developing agent scraping member whose tip is in contact with the developing agent conveying face of the rotating paddle for scraping developing agent adhering to the rotating paddle and a partition wall disposed at a position between the developing agent scraping member and the cleaning member, corresponding to a region outside of a region in which an image is formed on the image bearing body in a longitudinal direction of the cleaning member.
Further, according to still another aspect of the present invention, there is provided an image forming apparatus comprising a developer for developing a static latent image on an image bearing body using developing agent, a transfer unit for transferring a developed developing agent image on a transfer member and a cleaner disposed so as to be in a sliding contact with the surface of the image bearing body for removing developing agent remaining on the image bearing body after the transferring, the cleaner including a cleaning member for removing developing agent remaining on the image bearing body from the image bearing body, a rotating paddle having a developing agent conveying face for conveying developing agent removed from the image bearing body by the cleaning member upward from a portion near the image bearing body while rotating, a developing agent scraping member whose tip is in contact with the developing agent conveying face of the rotating paddle for scraping developing agent adhering to the rotating paddle and a partition wall disposed at a position between the developing agent scraping member and the cleaning member, corresponding to a region outside of a region in which an image is formed on the image bearing body in a longitudinal direction of the cleaning member, wherein assuming that an angle between a tangent line of the developing agent conveying face of the rotating paddle and a tangent line of the image bearing body is ∠&thgr;1 at a position in which the tip of the rotating paddle approaches the image bearing body most and the ∠&thgr;1 in the center of the rotating paddle is ∠&thgr;1A while the ∠&thgr;1 at the tip of the rotating paddle is ∠&thgr;1B, the rotating paddle has a curved shape so as to satisfy an inequality of ∠&thgr;1A>∠&thgr;1B.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.
REFERENCES:
patent: 4364660 (1982-12-01), Oda
patent: 4501620 (1985-02-01), Oda
patent: 4
Sanmonji Yoshinori
Yuge Keiji
Foley & Lardner
Grimloy Arthur T.
Ngo Hoang
Toshiba Tec Kabushiki Kaisha
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