International Business Machines Corporation

Allison H Caudill

Jerry J Abbott

John A Thompson

William J Bernardelli

Lowell M Simson

William H Bruce, Jr

Charles A Campbell

James W Stanley

A clamping device for securing a photoconductor in the form of a closed loop, flexible sleeve on a drum having a channel on the drum periphery, and with the channel running substantially parallel to the drum central axis, along the length of the drum, is disclosed. The clamping device comprises an elongated bar having a cross-sectional configuration for fitting within the channel, means for latching the bar to the drum when the bar is in position within the channel, and an electrically conducting spring positioned relative to the bar and the sleeve for making an electrical connection between the photoconductor sleeve and the drum, and for applying variable tension to the sleeve in response to forcing of the sleeve partially into the channel by the bar.

Photoconductor tensioning device

A magnetic brush developer having a toner dispenser cooperable with a removable toner container of the bottle type so that transfer of toner to the dispenser occurs without spillage or exposure of the toner to the external environment. The bottle and dispenser have mating interfaces which must be properly located, and then rotated, before dumping of toner from the bottle to the dispenser can occur. The dispenser interface is positioned in a slidable cover so that the bottle's toner content can be evenly distributed along the length of the dispenser, this length corresponding substantially to the length of the developer's development zone.

Toner container and toner dispensing apparatus

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.

Optimum preclean corona current for eliminating the accumulation of

For use in an electrophotographic copy machine utilizing magnetic brush roll development, an improved hollow magnetic roll made of non-magnetic material containing axially located grooves along the exterior periphery. The grooves are spaced in a range from 15-25 times the diameter of the permeable carrier beads used in the development process and the lands between grooves are polished to a high degree, e.g., 25 .mu. inches. The depth of the grooves is to a minimum of 1-2 times bead diameter while the groove width is to a minimum of 2-3 times bead diameter.

Grooved magnetic brush roll

An auger fed magnetic brush developer wherein two parallel augers continuously recirculate the developer mix and cause the mix to be enriched with toner prior to its being returned to the magnetic brush roll. A supply auger communicates with the brush roll along its entire length and directly elevates the mix to a lower part of the brush roll's surface. This supply auger includes four flutes of a pitch equal to one-half the length of the brush roll. This auger flute arrangement insures that a uniform supply of mix is presented to the brush roll along its entire length. In addition, this supply auger construction insures that a uniform supply of enriched mix is presented to the brush roll along its entire length, since the gradually depleting carrier tends to be presented to the brush roll a minimum number of times, for example three, prior to its exiting one end of the supply auger. The carrier exiting the supply auger enters a turnaround compartment whereat new toner is added. The depleted carrier and new toner is mixed by a return auger. To insure adequate triboelectric agitation, the return auger includes two flutes of a pitch equal to that of the supply auger. The two augers are rotated at different flute and pitch related speeds which insure equal flow through the augers. The two augers are of equal length, and are longer than the brush roll. The two augers are mounted in axially offset fashion, with the opposite end of each auger substantially coextensive with opposite ends of the brush roll, and with the other end of each auger extending into end disposed turnaround compartments.

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Lafayette, CO, United States of America

Allison H Caudill