Abstract: In this proposal a method of multilevel halftoning is described that allows the definition of halftone patterns using more than two gray levels at a time. This feature can be employed to eliminate the texture contours produced when shades formed by a pattern of two levels blends into a shade formed by a single gray level. The method also gives control over the degree to which a given output gray level is used. This can be employed to limit ink coverage when certain levels require more ink to produce than do others. According to the method: initial pixel intensity ranges are obtained; the initial pixel intensity ranges are compared to at least two overlapping threshold arrays; and selection of enhanced pixel intensity levels are determined for halftone cells according to the comparison results of the initial pixel intensity ranges to at least two overlapping threshold arrays wherein the enhanced pixel intensity levels are a function of results from the comparison.
Type:
Grant
Filed:
July 1, 1997
Date of Patent:
January 11, 2000
Assignee:
Xerox Corporation
Inventors:
Steven J. Harrington, R. Victor Klassen
Abstract: A method for color error diffusion using semi-vector quantization is proposed that simplifies error diffusion calculations. When three color separations are used, the two separations with the most visually perceptive color output are compared with one another to determine their output colors, while the third, least visually perceptive separation, is treated separately. A correction term may be applied to the third separation based on the color output of the first two separations to insure uniformity of ink coverage. This method yields results close to vector quantization and also minimizes fluctuation in the two most visually perceptive output colors. Of course, this method may be used with more than three color separations. For example, when four color separations are used, the least visually perceptive color is processed differently than the three other color separations.
Abstract: An image sensor array includes a plurality of photosensor chips, which are butted end-to-end to form a single linear array of photosensors. Each individual chip in the array is provided with an independently-addressable output enable line and video output line. This configuration allows individual chips to be addressed to output image data at specific times and in a specific manner suitable for any kind of downstream circuitry.
Type:
Grant
Filed:
March 30, 1998
Date of Patent:
January 11, 2000
Assignee:
Xerox Corporation
Inventors:
Scott L. Tewinkle, Paul A. Hosier, Jagdish C. Tandon
Abstract: An image formation system includes: a paper transport unit transporting paper along a paper transport passage; an image formation unit forming an image on an image carry belt; an image sense unit sensing a position of the image formed on the image carry belt; a transfer unit transferring the image formed on the image carry belt to the paper transported by the paper transport unit; a paper passage sense unit sensing paper passage on the paper transport passage, the paper passage sense unit being disposed upstream from a position where the image is transferred by the transfer unit; and a control unit controlling paper transport speed of the paper transport unit based on the sense results of the image sense unit and the paper passage sense unit.
Abstract: Special stochastic screens are generated to eliminate the moire between stochastic screens and checkerboard inputs. Using the checkerboard pattern, we can divide the entire stochastic screen S into two subsets: S.sub.1 is defined by all pixels, which lie on the white half of the checkerboard, and S.sub.2 is by the black half. The design of a stochastic screen is a mathematical optimization process, which as a single-value merit function as Q(S), so the design process can be described as maximizing Q(S). To eliminate the moire between the checkerboard input and the stochastic screen, the same design criteria to the two subsets, S.sub.1 and S.sub.2, individually, as well as to the entire set S is applied.
Abstract: A data transmission apparatus having a storage device for storing at least one structure data piece of a data processing device in a receiving data processing apparatus, a computation device for computing a transmission error detection code from the structure data stored in the storage device and a device for attaching the transmission error detection code computed by the computation device to the structure data stored in the storage device.
Abstract: An image processing apparatus for converting input color image signals to image recording signals to be sent to an image forming apparatus. The image processing apparatus comprises: a first color converting unit for converting the input color image signals to three-variable color signals independent of devices; a second color converting unit for converting the three-variable color signals to the image recording signals; and a parameter determining unit for determining parameters of the first color converting unit. The parameter determining unit determines the parameters so as to make characteristic colors in the input color image signals coincide with predetermined colors and to maintain linearities of color reproduction characteristics of an output image from the image forming apparatus.
Abstract: An solid state scanning system having a single crystal silicon deflection mirror and scanning mirror is integrated with a light source. Separation of the micro-electro-mechanical systems and light emitters on separate substrates allows the use of flip-chip and solder bump bonding techniques for mounting of the light sources. The separate substrates are subsequently full wafer bonded together to create an integrated solid state scanning system.
Type:
Grant
Filed:
December 1, 1998
Date of Patent:
January 11, 2000
Assignee:
Xerox Corporation
Inventors:
Philip D. Floyd, Decai Sun, Joel A. Kubby
Abstract: There is disclosed a color xerographic printing system which utilizes one full length developer to develop a first latent image and registration marks on the margins along the first latent image. The color printing system of this invention, also utilizes a second developer which only covers the second latent image created over the first latent image to prevent the developed registration marks from attracting more toner.
Abstract: This invention relates to methods and applications of forming clusters of pixels in 2-D sensing and display arrays. Using TFT switches having more than one predetermined electrical characteristics. The array formed according to these teachings being used in sensing, displaying, adjusting resolution, color selection, image processing, object recognition and filtering.
Type:
Grant
Filed:
October 21, 1996
Date of Patent:
January 4, 2000
Assignee:
Xerox Corporation
Inventors:
Ping Mei, James B. Boyce, Robert A. Street, David K. Fork
Abstract: A system controls the laser-induced discharging of pixel-sized image areas on a photoreceptor in a multi-color xerographic printer where multiple layers of toner are placed on the photoreceptor surface. A light collector, disposed to collect light either reflected from or passing through the photoreceptor, detects conditions in which the laser must pass through one or more layers of previously-placed toner to discharge the photoreceptor. When such a condition is detected, the system increases either the intensity or exposure duration of the laser.
Abstract: A method in which first and second representations of a document are provided, for example, by being made available on one or more server computers connected to a computer network, such as the Internet or a corporate intranet. The first and second representations are resolution-dependent structured representations and have, respectively, first and second characteristic resolutions, the second resolution being greater than the first. The first representation, but not the second, is provided in digital form to an untrusted recipient. For example, the first representation can be transmitted through the network from the server on which the first representation is available to a client computer connected to the network. The second representation is converted to a third representation of the document, the third representation being a representation in a human-readable, nondigital form.
Type:
Grant
Filed:
November 8, 1996
Date of Patent:
January 4, 2000
Assignee:
Xerox Corporation
Inventors:
Daniel P. Huttenlocher, William J. Rucklidge, John Seely Brown
Abstract: A gradient index lens assembly is formed by joining a plurality of separate lens arrays end to end to form a lens array assembly of extended length. This concept is especially useful in machines for copying large documents where lens arrays of up to 36 inches in length are required. A single lens array of this length is expensive to manufacture but can be approximated by three shorter 12-inch lenses at a fraction of the price of the single, unitary lens. Each of the plurality of the lens arrays are masked at their end, the mask overlapping the end fibers. The lens arrays are joined together in an alternate staggered configuration so that light transmitted through each lens array is optically coupled or stitched at the interfaces to optically form a single, continuous line of exposure at an image plane.
Abstract: A fuser member having a) a substrate; and thereover b) a filled polymeric outer layer with a zinc compound dispersed therein; and thereover c) a fluid release agent with molecules having amino functionality.
Type:
Grant
Filed:
September 19, 1997
Date of Patent:
January 4, 2000
Assignee:
Xerox Corporation
Inventors:
Clifford O. Eddy, Arnold W. Henry, Samuel Kaplan, Che C. Chow, James B. Maliborski
Abstract: An electrophotographic photoreceptor comprising an electrically-conductive substrate having thereon at least a photosensitive layer and a surface protective layer: wherein the surface protective layer has a network structure formed by the reaction of hydroxyl group-containing compounds with an isocyanate group-containing compound; and wherein at least one of the hydroxyl group-containing compounds is an electric charge-transporting material containing a hydroxyl group. Also disclosed are a preparation process of the electrophotographic photoreceptor and an image forming apparatus comprising the electrophotographic photoreceptor.
Abstract: A device and method for automatically adjusting conditioner metering roll liquid film thickness. The device including a transfer roll that mates with a back-up roll to form a nip through which a sheet passes for wetting a side of the sheet. A metering roll mates with the transfer roll and has a portion thereof positioned in a liquid filled sump for liquid to be added to an outside surface thereof. An optical sensor is positioned to detect the type of reflected light from the liquid on the outside surface of the metering roll and gives off a signal that is received by a controller that actuates a stepper motor to move the metering roll in a predetermined direction until the correct liquid thickness is obtained on the surface of the metering roll.
Abstract: A carrier comprised of a core and a polymer coating of (1) styrene/monoalkylaminoalkyl methacrylate or (2) styrene/dialkylaminoalkyl methacrylate.
Type:
Grant
Filed:
August 26, 1998
Date of Patent:
January 4, 2000
Assignee:
Xerox Corporation
Inventors:
Angelo J. Barbetta, Robert D. Bayley, Thomas R. Hoffend, Scott M. Silence, K. Derek Henderson, Carol A. Fox, John G. VanDusen
Abstract: A process for the preparation of colored dispersions which comprises adding colorant, a liquid vehicle, a free radical initiator, and a stable free radical agent to a microfluidizer; heating at a temperature of from about 100 to about 160.degree. C.; and thereafter, optionally cooling.