Having Halftone Screen Patents (Class 399/180)
  • Patent number: 11740568
    Abstract: In an example of the disclosure, an imaging oil is applied upon a photoconductor surface. An element is brought into contact with the imaging oil at the photoconductor surface. The element has a first refractive index that is within a predefined tolerance of a second refractive index of the imaging oil. The photoconductor surface is exposed to light emitted by a writing component. The light passes through the element and the imaging oil.
    Type: Grant
    Filed: September 18, 2018
    Date of Patent: August 29, 2023
    Assignee: Hewlett-Packard Development Company, L.P.
    Inventors: Lavi Cohen, Sasha Zilbershtein, Michael Vinokur, Michael Plotkin
  • Patent number: 8922834
    Abstract: A method is disclosed. The method includes generating a Continuous Tone Image (CTI) with all pixel values same as a first gray level, generating an initial Half Tone Image (HTI) with all pixel values equal to minimum absorptance level and computing a change in pixel error for a first pixel. The change in pixel error is computed by identifying a first pixel indicated in a valid pixel map, toggling the first pixel with all the possible output states and swapping the first pixel with all neighbor pixels only if the stacking constraint is satisfied, updating the HTI with the maximum error decrease operation and continue to next pixel location till the end criteria is met.
    Type: Grant
    Filed: April 5, 2012
    Date of Patent: December 30, 2014
    Assignee: Ricoh Production Print Solutions LLC
    Inventors: Kartheek Chandu, Mikel J. Stanich, Chai Wah Wu, Barry M. Trager
  • Patent number: 8665487
    Abstract: Various systems, methods, and programs embodied in computer readable media are provided for calibration of at least one half-tone density in a printer. In one approach, a method is provided comprising the steps of acquiring a plurality of half-tone density values from a respective plurality of test patches generated on a belt in the printer over a period of time, each of the test patches embodying an intended half-tone density, generating a mathematically smoothed half-tone density value from the half-tone density values, and calibrating a half-tone density in the printer based upon the mathematically smoothed half-tone density value.
    Type: Grant
    Filed: April 30, 2004
    Date of Patent: March 4, 2014
    Assignee: Hewlett-Packard Development Company, L.P.
    Inventor: Dennis A. Abramsohn
  • Patent number: 8643910
    Abstract: An image forming apparatus includes an acquiring unit that acquires image data expressing an image region included in an image with a first value and a background region included in the image with a second value; a segmenting unit that segments the image region into multiple segments arranged in a fast scanning direction; a converting unit that converts a value of at least one of the segments into the second value; an output unit that generates an image signal on the basis of the image data and outputs the image signal; an exposure unit that exposes a charged image bearing member to light according to the output image signal by scanning the light thereto in the fast scanning direction so as to form a latent image; and a developing unit that forms the image by developing the latent image using an invisible toner that absorbs infrared light or ultraviolet light.
    Type: Grant
    Filed: July 27, 2011
    Date of Patent: February 4, 2014
    Assignee: Fuji Xerox Co., Ltd.
    Inventor: Junichi Ichikawa
  • Patent number: 8576451
    Abstract: As set forth herein, computer-implemented methods and systems facilitate the generation of halftone screens for moiré-free color halftoning. A first fundamental frequency vector and a second fundamental frequency vector of a halftone cell are sheared using a selected shearing value. The shearing value is selected as an offset in a fast scanning or slow scanning direction. The selected shearing value satisfies various moiré-free conditions associated with the identified frequency vectors and is capable of being selected for multiple halftone screens. The halftone screens generated using the sheared frequency vectors are used for moiré-free halftoning.
    Type: Grant
    Filed: July 8, 2011
    Date of Patent: November 5, 2013
    Assignee: Xerox Corporation
    Inventors: Shen-Ge Wang, Zhigang Fan, Robert Paul Loce
  • Patent number: 8208175
    Abstract: A target pixel is processed according to a blended combination of two or more error diffusion techniques. For example, the two or more techniques may include a standard error diffusion technique and rank ordered error diffusion. Additionally, or alternatively, a quantization resolution is selected for the target pixel based on information regarding the pixel. For example, a quantization resolution is selected based on a relative position of the target pixel or based on a value of the target pixel and/or values of pixels neighboring the target pixel.
    Type: Grant
    Filed: April 13, 2005
    Date of Patent: June 26, 2012
    Assignee: Xerox Corporation
    Inventors: Beilei Xu, Robert Paul Loce
  • Patent number: 8175483
    Abstract: An image forming apparatus includes: print data generating unit for generating gradation correction test chart print data to juxtapose and draw a basis density pattern having a basis density of a yellow color and plural reference density patterns having respective densities of the yellow color compared with the basis density and additionally draw a contrast effect pattern composed of colors having a contrast effect on the yellow color; printing unit for printing a gradation correction test chart including a yellow color gradation correction pattern in which the basis density pattern and the plurality of reference density patterns are juxtaposed and printed and the contrast effect pattern is additionally printed; receiving unit for receiving an input of a density adjustment value of any pattern based on a shading comparison of the basis density pattern and the reference density patterns; and gradation correcting unit for performing a gradation correction.
    Type: Grant
    Filed: September 2, 2009
    Date of Patent: May 8, 2012
    Assignee: Fuji Xerox Co., Ltd.
    Inventors: Seiji Shiraki, Yasuo Komatsu, Kiyoshi Une, Takumi Nishikata
  • Patent number: 8125665
    Abstract: An image processing system includes a printing unit configured to print an image, a managing unit configured to manage charging information that can be reduced according to print processing performed by the printing unit, and a control unit configured to slow down the print processing performed by the printing unit if an available printing remaining amount indicated by the charging information is less than a predetermined value.
    Type: Grant
    Filed: May 29, 2008
    Date of Patent: February 28, 2012
    Assignee: Canon Kabushiki Kaisha
    Inventor: Nobuaki Miyahara
  • Patent number: 7684736
    Abstract: An image forming apparatus for forming a color image of CMK color plates by electrophotography system in which a K color plate having highest visibility among CMYK colors is composed of a rational number mesh. Profile of halftone dots (201Kh) becomes constant substantially and the factor for generating streak and unevenness is suppressed. Furthermore, C color plate and M color plate are formed of super cells and the K color plate, C color plate and M color plate are formed at an interval of 30°. Consequently, a Rosetta formed of halftone dots (201Ch, 201Mh, 201Kh) of CMK is optimized and the factor for generating moiré component is suppressed.
    Type: Grant
    Filed: January 25, 2006
    Date of Patent: March 23, 2010
    Assignee: FUJIFILM Corporation
    Inventor: Makoto Sugizaki
  • Patent number: 7215444
    Abstract: Conventional design tools were not developed for designing square zero-shift supercells. Conventionally, solutions that enable square zero-shift supercells were found by trial and error or by exhaustive analysis. According to a first design criterion of this invention, a non-square supercell in a first frame of reference has a diagonal that is equal in length to the diagonal of a square supercell in a second frame of reference rotated at a desired screen angle to the first frame of reference. The screen angle is a function of the lengths of the sides of the non-square supercell in the first frame of reference. According to a second design criterion, if the area of the corresponding square supercell in the second frame of reference is an integer, a square zero-shift supercell can be designed based on the lengths of the sides of the non-square supercell in the first frame of reference.
    Type: Grant
    Filed: July 16, 2002
    Date of Patent: May 8, 2007
    Assignee: Xerox Corporation
    Inventor: Charles M. Hains
  • Patent number: 6606470
    Abstract: A method for reducing edge effect (white gapping) between objects formed on a photoconductive member of an imaging device includes, during processing of a given color plane, partially exposing the photoconductive member for all image data that specifies a color to be developed on at least one color plane but that specifies no color to be developed on the given color plane. As such, the partial exposing does not enable development of that image data during image processing of the given color plane. By partially exposing objects that do not include a color to be developed on the color plane currently being processed, and while normally exposing adjacent objects that include a color to be developed on the current color plane, the lateral electric field effects between the objects is reduced and, thus, toner development for the given color plane is more edge precise for reduced white gapping between the objects.
    Type: Grant
    Filed: September 28, 2000
    Date of Patent: August 12, 2003
    Assignee: Hewlett-Packard Development Company, L.P.
    Inventors: Mark Wibbels, Victor Loewen
  • Patent number: 5786843
    Abstract: An improved method of line screen printing. Instead of screening the image with only one set of lines, the image is also screened with a second set of lines, which are substantially orthogonal to those of the first set. (FIG. 3). The screening is accomplished with two types of cells, horizonal cells and vertical cells. The pixels are classified according to their distance from the nearest line in the horizontal cells. This process is repeated with respect to the vertical cells. (FIG. 5). Different tone curves, which map input pixel values to output pixel values, are associated with different pixel classifications. In general, pixels closer to lines have tone curves that map to higher output values. (FIGS. 6 and 7). Because each pixel is in both a horizontal cell and a vertical cell, each pixel has two values from the tone curves. For each pixel, its two tone curve values are combined to obtain a greyscale value for that pixel.
    Type: Grant
    Filed: September 27, 1996
    Date of Patent: July 28, 1998
    Inventor: Vadlamannati Venkateswar