International Business Machines Corporation

William J Bernardelli

John A Thompson

Allison H Caudill

Fred Young Brandon

Jerry J Abbott

A hot roll fuser includes a heated roller and a substantially non-deformable backup roll forming a nip through which a carrier with unfused toner may pass, the toner becoming fused by virtue of the heating action from the hot roll. A cleaning arrangement for cleaning the backup roll comprises a support and a pair of scraping blades, each supported in contacting relationship with the backup roll. To insure good scraping action, each of the blades has a serrated or interrupted scraping edge, and the serrations or interruptions of the first and second blades are offset so that the entire surface area of the backup roll is scraped either by the first or second blades, or both.

Backup roll cleaning system for a heated roll fuser

A magnetic-brush developer for use in an electrophotographic machine wherein the magnetic brush is used to transport toner-coated carrier particles to an elevated development zone from a pickup zone. A path for so moving the carrier is provided between the magnetic brush roll and an overflow plate, the lower end of which also serves as a doctoring blade. The carrier is moved to the top of the roll where a doctoring blade limits the amount of carrier entering the development zone. Excess carrier is accumulated in an expanded spatial area near the doctoring blade and returned to the vicinity of the pickup zone by falling back between the overflow plate and the housing. An area is provided near the doctoring blade at the top of the roll where no magnetic field is present. The overflow plate is made of non-magnetic material.

Electrophotographic developer with carrier overflow control

An electrophotographic machine of the transfer type in which tetrafluoroethylene-coated carrier beads transport toner particles to a development zone by virute of the triboelectric attraction between positive toner and negative tetrafluoroethylene. At the development zone, the carrier beads are crushed together and occasionally a piece of tetrafluoroethylene is worn off of the surface of the beads and carried along on the surface of the photoconductor. These tetrafluoroethylene-wear products are subjected to high level preclean corona current to reverse the triboelectric negative polarity thereof. In that manner, a positive wear product is made to act as though it was toner and is therefore carried out of the machine on copy paper. In a similar manner, paper dust and other contaminants on the photoconductor surface are subjected to a high level preclean corona current to receive a positive charge for being carried out of the machine on the copy paper.

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Longmont, CO, United States of America

William J Bernardelli