Patents by Inventor Mark A. Gwaltney
Mark A. Gwaltney 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: 7688473Abstract: Disclosed herein is an image processing method for producing enhanced halftone edges, particularly suited to those edges which only lie upon the background as apposed to those edges which abut other halftone screens. It utilizes a step of defining border pixels and a step of halftoning those border pixels in a different manner than the halftoning applied to the interior region of the tint or image segment. The preferred halftone for the border pixels will be related to the interior halftone by some number of common spatial frequency harmonics.Type: GrantFiled: October 26, 2004Date of Patent: March 30, 2010Assignee: Xerox CorporationInventors: Connie F. Purdum, Robert P. Loce, Beilei Xu, David J. Lieberman, Mark A. Gwaltney, Jon S. McElvain, Charles M. Hains
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Patent number: 7639389Abstract: Test image data is introduced into the image processing path of a marking device, at various points prior to the marking engine. Comparison of output of the marking engine from various sources of image data is made to diagnose imaging path component failure. Imaging data at various points in the image processing path is captured for analysis as part of component failure diagnosis. Various memory devices are used to both introduce test data at various points in the image processing path and capture data at various points of the image processing path.Type: GrantFiled: December 12, 2006Date of Patent: December 29, 2009Assignee: Xerox CorporationInventors: Paul M. Butterfield, Mark A. Gwaltney, Connie F. Purdum, Carlos O. Alva
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Publication number: 20080137124Abstract: Test image data is introduced into the image processing path of a marking device, at various points prior to the marking engine. Comparison of output of the marking engine from various sources of image data is made to diagnose imaging path component failure. Imaging data at various points in the image processing path is captured for analysis as part of component failure diagnosis. Various memory devices are used to both introduce test data at various points in the image processing path and capture data at various points of the image processing path.Type: ApplicationFiled: December 12, 2006Publication date: June 12, 2008Applicant: Xerox CorporationInventors: Paul M. Butterfield, Mark A. Gwaltney, Connie F. Purdum, Carlos O. Alva
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Patent number: 7110144Abstract: Method, system and computer-readable medium containing instructions for performing halftone gamma correction in a printing environment to achieve and maintain high print quality. The system includes one or more subsystems, including a tone reproduction subsystem that creates one or more print calibration pages, each having a tone curve defining a relationship between a plurality of input color levels, output color levels and a level of measured darkness. A pixel adjustment subsystem associates each input color level with one of the output color levels based on a desired percentage change in the level of measured darkness. Further, a gamma correction system performs gamma correction on a selected tone curve of one of the print calibration pages by associating each input color level with one of the output color levels based on the desired percentage change in the level of measured darkness in a substantially flat region of the selected tone curve.Type: GrantFiled: September 5, 2001Date of Patent: September 19, 2006Assignee: Xerox CorporationInventors: Shirley Cheng, Mark A. Gwaltney, Robert P. Loce, Martin S. Maltz, Connie F. Purdum
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Publication number: 20060087694Abstract: Disclosed herein is an image processing method for producing enhanced halftone edges, particularly suited to those edges which only lie upon the background as apposed to those edges which abut other halftone screens. It utilizes a step of defining border pixels and a step of halftoning those border pixels in a different manner than the halftoning applied to the interior region of the tint or image segment. The preferred halftone for the border pixels will be related to the interior halftone by some number of common spatial frequency harmonics.Type: ApplicationFiled: October 26, 2004Publication date: April 27, 2006Inventors: Connie Purdum, Robert Loce, Beilei Xu, David Lieberman, Mark Gwaltney, Jon McElvain, Charles Hains
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Publication number: 20050157317Abstract: A system and method for detecting and correcting color misregistration errors in a color image forming device. Spectrophotometric analysis is performed on special color registration patches to transform color registration errors into a color signal. The color registration patch is designed so the color shift detected by the spectrophotometer allows prediction of the amount of color misregistration.Type: ApplicationFiled: January 16, 2004Publication date: July 21, 2005Applicant: XEROX CORPORATIONInventors: Paul Butterfield, Mark Gwaltney, Timothy Sulenski
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Publication number: 20030048478Abstract: Method, system and computer-readable medium containing instructions for performing halftone gamma correction in a printing environment to achieve and maintain high print quality. The system includes one or more subsystems, including a tone reproduction subsystem that creates one or more print calibration pages, each having a tone curve defining a relationship between a plurality of input color levels, output color levels and a level of measured darkness. A pixel adjustment subsystem associates each input color level with one of the output color levels based on a desired percentage change in the level of measured darkness. Further, a gamma correction system performs gamma correction on a selected tone curve of one of the print calibration pages by associating each input color level with one of the output color levels based on the desired percentage change in the level of measured darkness in a substantially flat region of the selected tone curve.Type: ApplicationFiled: September 5, 2001Publication date: March 13, 2003Applicant: Xerox CorporationInventors: Shirley Cheng, Mark A. Gwaltney, Robert P. Loce, Martin S. Maltz, Connie F. Purdum
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Patent number: 6456394Abstract: A method is disclosed for reducing halo print defects occurring in printed/copied color images. The method includes detecting a boundary between a first image object and a second image object within a color separation of the color document, and modifying the video values of a plurality of pixels within the color separation so that the video values slope toward the boundary, the plurality of pixels being located within a transition zone adjacent the boundary. In the case where toner black is used, the video values of a plurality of pixels within a transition zone of a toner black color separation are modified so that the video values ramp or slope down toward the boundary, and the video values of a plurality of pixels within transition zones of a cyan color separation, a magenta color separation, and a yellow color separation are modified so that the video values ramp or slope up toward the boundary. In effect, the process increasingly replaces toner black with process black (i.e.Type: GrantFiled: December 10, 1998Date of Patent: September 24, 2002Assignee: Xerox CorporationInventors: Mark A. Gwaltney, Kevin M. Sheridan
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Patent number: 5867198Abstract: An improved method for estimating toner usage in digital xerographic printers and copiers. The method is characterized by taking into account digital image dot spreading which results in the area of a pixel not being developed fully and some areas outside of the pixel being developed. Thus, the improved method takes into account the departure of a developed image from an ideal shape (i.e. square). To this end, the improved method compensates for departure of a developed image from an ideal shape. In carrying out the method estimated toner usage is based on pixel groupings rather than simple pixel counting.Type: GrantFiled: August 12, 1996Date of Patent: February 2, 1999Assignee: Xerox CorporationInventors: Mark A. Gwaltney, David R. Wyble
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Patent number: 5751432Abstract: Apparatus and method for glossing certain areas of a substrate. In particular, highlight images are created by incorporating in some of the images on a substrate a clear polymer material thereby providing them with a larger mass thereby resulting in a higher gloss than those images on the same substrate which do not contain the additional clear polymer.Type: GrantFiled: May 31, 1996Date of Patent: May 12, 1998Assignee: Xerox CorporationInventor: Mark A. Gwaltney
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Patent number: 5600430Abstract: In a multi-color imaging apparatus utilizing a recharge step between two image creation steps for recharging a charge retentive surface to a predetermined potential pursuant to forming the second of the two images, a first corona generating device recharges the charge retentive surface to a higher absolute potential than a predetermined potential, and then a second corona generating device recharges the charge retentive surface to the predetermined potential. An electrical charge associated with the first image is substantially neutralized after being recharged by the first and second corona generating device.Type: GrantFiled: November 30, 1994Date of Patent: February 4, 1997Assignee: Xerox CorporationInventors: Jeffrey J. Folkins, Roger L. Bullock, Thomas J. Fleck, Kenneth W. Pietrowski, Charles H. Tabb, Zhao-Zhi Yu, Mark A. Gwaltney
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Patent number: 5579100Abstract: In a multi-color imaging apparatus utilizing a recharge step between two image creation steps, a corona generating device is used to recharge the developed image areas and untoned areas of a charge retentive surface to a lower electrical potential than that associated with the developed image areas before recharge, so that the residual voltage associated with the developed image is substantially reduced and a minimal level of negative charge is driven through the toner layer(s). An electrical charge associated with any previously developed images is substantially neutralized prior to development of any subsequent images thereon.Type: GrantFiled: December 23, 1994Date of Patent: November 26, 1996Assignee: Xerox CorporationInventors: Zhao-Zhi Yu, Charles H. Tabb, John F. O'Brien, James R. Beachner, Mark A. Gwaltney, Meng H. Lean, Jeffrey J. Folkins
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Patent number: 5559579Abstract: A developer control for enabling the use of developer and toner materials with widely varying At in high quality xerographic copying and printing. Pixel count data is combined with toner test patch reflectance data during a brief toner rundown to determine the rate of change of density per unit change in toner concentration. During toner rundown, dispensing of toner is suspended for a period of time for effecting toner concentration reduction by approximately 0.25%. The change in Toner Concentration (TC) is estimated using pixel counting. Additionally, toner test patches are created and the reflectance thereof is measured for determining the change in toner density. The estimated TC change and the change in toner density are processed using linear regression to find the average change in density sensor output for the estimated change in TC which is referred to as the rundown slope. The rundown slope is then compared to a target value.Type: GrantFiled: September 29, 1994Date of Patent: September 24, 1996Assignee: Xerox CorporationInventors: Mark A. Gwaltney, Robert E. Grace
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Patent number: 5491538Abstract: A printing machine of the type in which a latent image recorded on an image bearing surface is developed with toner to form a visible image thereof, includes a development apparatus for developing the latent image. The development apparatus includes a housing storing a supply of magnetically-attractable developer material containing toner. A moving flexible donor belt mounted within the housing spaced from the image bearing surface transports developer to a development zone adjacent the image bearing surface. A magnetic member attracts and transports the developer material within the housing to the donor belt. A plurality of selectively-actuable electrodes embedded within the donor belt are biased to create a powder-cloud of toner particles within the development zone. Within the development zone, the flexible donor belt moves over a pair of spaced apart support rollers defining the width of the development nip.Type: GrantFiled: July 5, 1994Date of Patent: February 13, 1996Assignee: Xerox CorporationInventor: Mark A. Gwaltney