Patents by Inventor Alan S. Campbell
Alan S. Campbell has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 9927762Abstract: In an imaging device having a photoconductive drum and a lubricant applicator brush, methods and apparatus teach application of the lubricant to the drum at a transfer nip and removing undeveloped toner particles. A first voltage is applied to the drum while the brush receives a voltage that switches more positive and more negative than the first voltage. It attracts to the brush from the drum negatively and positively charged toner. Embodiments contemplate amounts of voltages and frequencies of switching. An elongate rod contacts the brush downstream of the transfer nip to flicker off the toner particles from the brush. The rod can also have voltages applied and switched greater than and lesser than the voltages of the applicator brush to facilitate toner removal. A cleaning blade downstream of the transfer nip scrapes clean a surface of the drum.Type: GrantFiled: May 31, 2016Date of Patent: March 27, 2018Assignee: LEXMARK INTERNATIONAL, INC.Inventors: Michael J Dixon, Pramod K Sharma, Alan S Campbell
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Publication number: 20170343954Abstract: In an imaging device having a photoconductive drum and a lubricant applicator brush, methods and apparatus teach application of the lubricant to the drum at a transfer nip and removing undeveloped toner particles. A first voltage is applied to the drum while the brush receives a voltage that switches more positive and more negative than the first voltage. It attracts to the brush from the drum negatively and positively charged toner. Embodiments contemplate amounts of voltages and frequencies of switching. An elongate rod contacts the brush downstream of the transfer nip to flicker off the toner particles from the brush. The rod can also have voltages applied and switched greater than and lesser than the voltages of the applicator brush to facilitate toner removal. A cleaning blade downstream of the transfer nip scrapes clean a surface of the drum.Type: ApplicationFiled: May 31, 2016Publication date: November 30, 2017Inventors: MICHAEL J. DIXON, PRAMOD K. SHARMA, ALAN S. CAMPBELL
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Patent number: 7710441Abstract: An imaging system comprises a laser source for emitting a beam, a photoconductive surface, a scanning device and a controller. The controller designates at least a first part and a second part of each line of image data, corresponding to a first part and a second part of each associated sweep of the beam. The laser source is modulated based upon the first part of the line of image data during the first part of a first one of the associated sweeps of the beam. The laser source is not modulated according to image data for the second part of the first one of the sweeps. During the first part of a second one of the associated sweeps of the beam, the laser source is not modulated based upon image data. However, the laser source is modulated based upon the second part of the line of image data during the second part of the second one of the sweeps.Type: GrantFiled: March 20, 2006Date of Patent: May 4, 2010Assignee: Lexmark International, Inc.Inventors: Alan S. Campbell, David B. Langer, David A. Schneider
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Patent number: 7277111Abstract: An electrophotographic device comprises a printhead having at least one laser associated with a corresponding photoconductive surface. Where multiple laser beams are associated with the same photoconductive surface, the laser beams are spaced a predetermined distance from one another in a process direction, which is orthogonal to a scan direction in which the laser beams are swept. The electrophotographic device operates at one of at least two image transfer rates. A controller in the electrophotographic device selectively directs image data to the printhead based, at least in part, upon the selected image transfer rate, the facet resolution, and/or the desired output image resolution. The print speed can thus be adjusted over a relatively wide range.Type: GrantFiled: January 28, 2005Date of Patent: October 2, 2007Assignee: Lexmark International, Inc.Inventors: Alan S. Campbell, Cary P. Ravitz, John P. Richey
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Patent number: 5500724Abstract: In a liquid toner electrophotographic printer (1), an abrasive blade (5), located between the cleaning station (19) and the charging station (9) disturbs the outer, photoconductive surface of drum (3) to continuously rejuvenate that surface. The abrasion merely disturbs the surface and may be accomplished by alternative abrasive mechanisms.Type: GrantFiled: March 23, 1995Date of Patent: March 19, 1996Assignee: Lexmark International, Inc.Inventors: Alan S. Campbell, Donald L. Elbert, William C. McCornack, Eric L. Ziercher
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Patent number: 5406356Abstract: An electrophotographic device (1) in which a photoconductor drum (3) is charged by a charging roller (5). Insulating liquid (19, 30) is applied at their initial nip. The charging roller both charges and squeegees largely dry the photoconductor member. The liquid (19) may be produced by incomplete cleaning by a cleaning blade (21). Excess liquid is collected at the sides.This results in reduction in foreign gasses, and reduction in the operating potential between photoconductor drum and charging roller.Type: GrantFiled: August 9, 1993Date of Patent: April 11, 1995Assignee: Lexmark International, Inc.Inventors: Alan S. Campbell, Curt J. Claflin, Randy L. Fagerquist, Tracy G. Floyd, Brenda M. Kelly, Ronald L. Roe, Eric L. Ziercher
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Patent number: 4870433Abstract: An array of resistive heater elements, each of which is connected in an electrical circuit between a common electrode and one of the control electrodes. Each of the resistive heater elements comprises a plurality of portions arranged so that a small elongated opening in provided at the middle of the heater element where no resistive material is present. Each of the resistive heater elements, when energized, has a bubble formed at each of the plurality of portions. All of the bubbles coalesce to form a single pillow-shaped bubble which causes a drop of ink to be ejected from the associated nozzle. During collapse of the bubble, the bubble collapses inwardly so that cavitational shock impacts the heater element at the opening and little or no damage to the resistive heater is produced.Type: GrantFiled: July 28, 1988Date of Patent: September 26, 1989Assignee: International Business Machines CorporationInventors: Alan S. Campbell, Jerome M. Eldridge, Francis C. Lee, Graham Olive
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Patent number: 4199767Abstract: Disclosed is improved apparatus for inhibiting the emission of a stream of ink drops from the nozzle orifice of an ink jet printer. The apparatus comprises a valve which is located externally of the head associated with the nozzle, and adjacent the outlet orifice of the nozzle. The valve includes a resilient gate member which is mounted for movement with respect to the outlet orifice but adjacent thereto, the gate member being movable between a first position allowing an uninhibited emission of a stream of ink drops from the outlet orifice of the nozzle and a sealing position of the outlet orifice when the gate member is in a second position. In this connection, the outlet orifice serves as a seat for the gate member when the member is in the second position. Moreover, the gate member is preferably composed of a thin but resilient material which is biased into a sealing engagement with the seat at least when the gate member is in the second position.Type: GrantFiled: February 21, 1979Date of Patent: April 22, 1980Assignee: International Business Machines CorporationInventors: Alan S. Campbell, Jack H. Jennings