Patents by Inventor Raghulinga R. Thettu
Raghulinga R. Thettu 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: 4640504Abstract: An apparatus for feeding individual substrates from the top of a stack of substrates upon demand includes a paddle wheel having paddles that are semi-cylindrical. The paddles buckle upon contact with the substrates rather than bending and thereby providing reduced normal force sensitivity to paddle deflection and reduced pressure since the force of buckling is a function of the paddle cross-section rather than paddle length for all areas of the paddles except near the paddle wheel hub. The semi-circular blades reduce misfeeding and multifeeding while having an extended wear life.Type: GrantFiled: July 2, 1984Date of Patent: February 3, 1987Assignee: Xerox CorporationInventors: Gerald M. Garavuso, Shwu-Jian Liang, Raghulinga R. Thettu
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Patent number: 4372668Abstract: Reproducing apparatus with a stationary optical system, a reciprocating platen to transport a document across the stationary optical system, a copy sheet feeding apparatus and a copy sheet registration apparatus to feed a copy sheet in synchronism with the transport of a document by the platen. The platen has mechanical means such as a linear cam to actuate the copy sheet registration apparatus and the copy sheet registration apparatus is responsive to the platen actuating means to directly actuate the copy sheet registration apparatus.Type: GrantFiled: December 24, 1980Date of Patent: February 8, 1983Assignee: Xerox CorporationInventors: Michael A. Malachowski, Victor Shur, Raghulinga R. Thettu
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Patent number: 4335950Abstract: Xerographic reproducing apparatus including a frame assembly made up of upper and lower molded plastic frame members, each frame member having sheet guiding elements integrally molded therein so that a sheet of copy paper being processed through the reproducing apparatus is guided along its path by the sheet guiding elements in the upper and lower molded plastic frame members. In a specific embodiment each of the frame members may have several machine element mounting means integrally molded therein and they are pivotally mounted relative to each other in clam shell fashion at one end and when in the closed position are securely positioned by cooperating datum points. With such construction control over the positioning of machine elements and in particular the paper path may be achieved at the time of construction and the cost and complexity of construction can be substantially reduced.Type: GrantFiled: December 24, 1980Date of Patent: June 22, 1982Assignee: Xerox CorporationInventors: Edward J. Gunzelmann, Raghulinga R. Thettu, Larry M. Wood
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Patent number: 4294540Abstract: In a document handling system in which documents are moved on an apertured belt over a vacuum manifold to an imaging station of a copier, the vacuum manifold surface engaging the backside of the belt contains narrow, spaced apart, shallow grooves extending in the direction of movement of the belt. Vacuum is applied to the belt only through these grooves, to reduce belt/manifold friction. These manifold surface grooves have light reflective bottom surfaces closely spaced below the back of the belt to underlie the belt apertures and reduce their printout through translucent documents. The apertures in the vacuum belt are only in narrow bands overlying the grooves in the vacuum manifold. The apertures in the vacuum manifold are also preferably transversely spaced from the vacuum belt apertures so that they are not aligned during the belt movement.Type: GrantFiled: January 10, 1980Date of Patent: October 13, 1981Assignee: Xerox CorporationInventor: Raghulinga R. Thettu
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Patent number: 4018555Abstract: A contact fuser assembly for use in electrostatic reproducing apparatus, said assembly including a heated fuser roll structure cooperating with a backup roll to form a nip through which copy sheets or substrate material having toner images thereon move with the toner images contacting the heated fuser roll structure. The fuser assembly is characterized by the provision of a cleaning arrangement comprising a roll having a tacky surface which is adapted to contact the fuser roll structure to thereby remove toner and other contaminants therefrom with subsequent embedding of the contaminants in the tacky surface. The cleaning arrangement is further characterized by the provision of means for maintaining the effectiveness of the cleaning arrangement.Type: GrantFiled: September 24, 1975Date of Patent: April 19, 1977Assignee: Xerox CorporationInventor: Raghulinga R. Thettu
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Patent number: 4013400Abstract: A contact fuser assembly for use in electrostatic reproducing apparatus including a heated fuser roll structure cooperating with a backup roll to form a nip through which copy sheets having toner images thereon move with the toner images contacting the heated fuser roll structure. The fuser assembly is characterized by the provision of a cleaning arrangement comprising a roll having a tacky surface which is adapted to contact the fuser roll structure to thereby remove contaminants therefrom. The cleaning arrangement is further characterized by the provision of means for rejuvenating the tacky surface of the cleaning roll wherein polymer material is applied to the cleaning roll and is tacky at the operating temperature of the fuser apparatus.Type: GrantFiled: July 21, 1975Date of Patent: March 22, 1977Assignee: Xerox CorporationInventors: Raghulinga R. Thettu, Michael J. Oszczakiewicz
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Patent number: 4004127Abstract: An apparatus for fusing toner images onto flexible support material in which the support material is transported in a path past a flash fusing lamp. The path is defined by an outer member and an inner member which guide the sheet past the flash fusing lamp. The inner member is made of a transparent material and the outer member is reflective. Warm air under pressure is used to advance the support material along its path and to crust the toner images facing inwardly toward the lamp to prevent offset and reduce energy requirements of the lamp to permanently fix the images to the support material.Type: GrantFiled: March 2, 1976Date of Patent: January 18, 1977Assignee: Xerox CorporationInventors: John M. Bailey, Raghulinga R. Thettu
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Patent number: 4000963Abstract: A contact fuser assembly for use in electrostatic reproducing apparatus including a heated fuser roll structure cooperating with a backup roll to form a nip through which copy sheets having toner images thereon move with the toner images contacting the heated fuser roll structure. The fuser assembly is characterized by the provision of a cleaning arrangement comprising a roll having a tacky surface which is adapted to contact the fuser roll structure to thereby remove contaminants therefrom. The cleaning arrangement is further characterized by the provision of means for rejuvenating the tacky surface of the cleaning roll wherein polymer material is applied to the cleaning roll and is tacky at the operating temperature of the fuser apparatus.Type: GrantFiled: July 21, 1975Date of Patent: January 4, 1977Assignee: Xerox CorporationInventor: Raghulinga R. Thettu
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Patent number: 3999510Abstract: Fuser apparatus for fixing toner images to substrates comprising a heated fuser roll structure and a backup roll structure forming a nip through which the substrates pass with the toner images contacting the heated fuser roll structure to thereby soften the toner images. A cleaning roll structure for removing toner offset to said fuser roll structure comprises an outer layer of silicone rubber containing relatively high surface energy filler particles (i.e. surface energy on the order of 30-95 dynes/centimeter when utilized with a fuser roll structure surface comprising polytetrafluoroethylene) which have a high affinity for the offset toner.Type: GrantFiled: January 2, 1975Date of Patent: December 28, 1976Assignee: Xerox CorporationInventor: Raghulinga R. Thettu
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Patent number: 3988817Abstract: An improved pressure roll construction for a heated pressure roll fusing apparatus. The pressure roll has an elastomeric core member made of silicone rubber covered by a rigid, flexible sleeve which can be made of metal or fluoroethylene-propylene. The sleeve is covered with an exterior coating made of silicone rubber to enhance paper handling characteristics in the fuser nip.Type: GrantFiled: December 18, 1973Date of Patent: November 2, 1976Assignee: Xerox CorporationInventor: Raghulinga R. Thettu
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Patent number: 3983393Abstract: A corona generating device including an elongated corona electrode in the form of a thin wire to which a corona generating potential is applied. The wire is partially surrounded by a conductive corona shield which may be grounded. Intermediate the wire and shield and spaced apart from each are various configurations of ozone reducing members which partially surround the wire. These members are coated with a catalytic material which reacts with the ozone in an area as close as possible to the area in which it is generated, preferably in the corona glow region, and thus have been found to be more effective in reducing the ozone.Type: GrantFiled: June 11, 1975Date of Patent: September 28, 1976Assignee: Xerox CorporationInventors: Raghulinga R. Thettu, Phillip L. Harrison, John Stavisky
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Patent number: 3970038Abstract: Fuser apparatus for fixing toner images to substrates comprising a heated fuser roll structure and a backup roll structure forming a nip through which the substrates pass with the toner images contacting the heated fuser roll structure to thereby soften the toner images. A cleaning structure for removing toner offset to said fuser roll structure comprises a plurality of flexible fingers supported for wiping contact with the fuser roll structure. Spaces between the finger serve as areas for collecting the toner to prevent the toner from re-applied to the fuser roll. The cleaning structure contacts areas of the fuser roll prior to such areas being contacted by a wick employed for applying offset preventing liquid to the fuser roll, such positioning of the fuser roll structure serving to prolong the life of the wick.Type: GrantFiled: January 2, 1975Date of Patent: July 20, 1976Assignee: Xerox CorporationInventor: Raghulinga R. Thettu
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Patent number: 3965973Abstract: A conductive heat transfer mechanism through which energy readily flows between two bodies or systems at different temperatures. The present mechanism is embodied in a temperature sensing network for determining and controlling the surface temperature of a xerographic fuser roll. The network includes a probe shoe containing at least one temperature sensing element with the shoe being positioned in close non-contiguous relation with the moving surface of a heated fuser roll. A magnetic flux field is created within the air gap between the heated roll surface and the probe shoe and a magnetic medium, preferably being in fluid form, having a relatively high coefficient of thermal conductivity is placed within the flux field through which a rapid and efficient flow of heat is maintained.Type: GrantFiled: November 13, 1974Date of Patent: June 29, 1976Assignee: Xerox CorporationInventors: Raghulinga R. Thettu, Xerox Corporation
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Patent number: 3965332Abstract: Apparatus of the type which fuses toner images onto support material by heat and pressure. A heated fuser roll includes a cylindrical member made of quartz which transmits radiant energy from a lamp source located on the interior of the cylindrical member. The cylindrical member is covered with a layer made of elastomeric material which also transmits radiant energy. A first reflector member is positioned adjacent the lamp source for focusing the radiant energy along a heat transfer zone segment of the elastomeric layer. Positioned adjacent to the heat transfer zone is a second reflector member to reflect the energy back to the surface of the layer. Tack and detack corotrons tack sheets bearing powder images to be fused to the surface of the elastomeric layer to selectively heat the powder images. A pressure roll forms a nip with the layer at the exit of the heat transfer zone to apply heat and pressure thereat.Type: GrantFiled: March 10, 1975Date of Patent: June 22, 1976Assignee: Xerox CorporationInventor: Raghulinga R. Thettu
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Patent number: 3948214Abstract: Apparatus of the type which fuses toner images onto support material by heat and pressure including an instantly heated fuser roll and a pressure back-up roll having an elastomeric surface. The fuser roll has a cylindrical member made of quartz or other material which transmits radiant energy from a source located on the interior of the cylindrical member. The cylindrical member has a first layer made of elastomeric material which transmits radiant energy. The first layer is covered with a second layer of material which absorbs radiant energy. A third layer of material covers the second layer of heat absorbing material to effect a good toner release characteristic on the fuser roll surface. The third or image contacting layer may be made of an elastomeric material where dry fusing is preferred or alternatively a rigid material where a silicone oil is applied to the image contact layer to prevent toner offset onto the fuser roll surface.Type: GrantFiled: February 4, 1975Date of Patent: April 6, 1976Assignee: Xerox CorporationInventor: Raghulinga R. Thettu
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Patent number: 3947108Abstract: An improved cleaning apparatus and process are provided including a cleaning means for removing toner particles and other particulate contaminants. A contaminant removal means is provided positioned between the cleaning means and the means for charging an electrostatic imaging member. The contaminant removal means which comprises a scrubber member is adapted to remove film-like contaminants which would otherwise cause deletions in the resulting copy sheet.Type: GrantFiled: May 20, 1974Date of Patent: March 30, 1976Assignee: Xerox CorporationInventors: Raghulinga R. Thettu, Donald J. Quant
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Patent number: 3934477Abstract: A conductive heat transfer mechanism through which energy readily flows between two bodies or systems at different temperatures. The present mechanism is embodied in a temperature sensing network for determining and controlling the surface temperature of a xerographic fuser roll. The network includes a probe shoe containing at least one temperature sensing element with the shoe being positioned in close non-contiguous relation with the moving surface of a heated fuser roll. A magnetic flux field is created within the air gap between the heated roll surface and the probe shoe and a magnetic medium, preferably being in fluid form, having a relatively high coefficient of thermal conductivity is placed within the flux field through which a rapid and efficient flow of heat is maintained.Type: GrantFiled: November 13, 1974Date of Patent: January 27, 1976Assignee: Xerox CorporationInventor: Raghulinga R. Thettu