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- Nachgewiesen in: USPTO Patent Grants
- Sprachen: English
- Patent Number: 5,193,008
- Publication Date: March 09, 1993
- Appl. No: 07/610,094
- Application Filed: November 07, 1990
- Assignees: DP-Tek, Inc. (Wichita, KS)
- Claim: What is claimed is
- Claim: 1. Apparatus for enhancing the image produced by a scanning laser beam printer, utilizing a charge pattern and toner to develop an image, said laser printer having a resolution comprised of a predetermined DPI (dots per inch) along parallel laser beam scan lines with the number of scan lines per inch corresponding to said DPI, said laser beam being normally selectively energized, at said predetermined DPI rate along said scan lines, at a predetermined dot-writing level sufficient to exceed a predetermined threshold of the imaging components, said threshold being determinative of the presence or absence of dots on the laser printer image, and said laser printer also having means for accepting an external video signal that controls the energizing of said laser beam, said apparatus comprising
- Claim: means for providing digital signals corresponding to a double DPI bit map of the desired image to be produced by said laser printer, said bit map having twice the predetermined DPI resolution of said laser printer;
- Claim: temporary storage means, coupled to receive said digital signals, for temporarily storing at least portions of three lines from said double DPI bit map, with one of said lines corresponding to a normal scan line of said laser printer and the other lines being the double DPI lines immediately above and below said scan line;
- Claim: means for extracting successive sets of three bits, one bit from each of said three lines at corresponding positions along said lines;
- Claim: logic means for decoding said three bits into up to five different values, each of said different values associated with one of a plurality of video pulse widths, some of said pulse widths being below said threshold level of said laser printer, but are of sufficient intensity to produce an image dot between scan lines when adjacent points on successive scan lines are energized just below the imaging threshold;
- Claim: means for generating scan lines of video signal at twice said predetermined DPI of said laser printer, but with the same number of scan lines as said laser printer, said video signal comprised of consecutive pulses of said pulse widths corresponding to the decoded values associated with the combinations of said three bits, and at least some of said pulse widths being below the predetermined threshold level of said laser printer;
- Claim: means for coupling said video signal to energize the laser beam of said laser printer;
- Claim: said apparatus including means for producing a complete image at a higher resolution than said predetermined DPI with a single pass of said laser beam; and
- Claim: said apparatus including means for providing a laser beam which extends more than half way between adjacent scan lines.
- Claim: 2. An apparatus as defined in claim 1 wherein a random access memory is provided for storing a double density bit map from which said digital signals are provided.
- Claim: 3. An apparatus as defined in claim 1 wherein said temporary storage means includes a plurality of random access memory FIFO circuits.
- Claim: 4. An apparatus as defined in claim wherein said bit extracting means includes a plurality of shift registers.
- Claim: 5. An apparatus as defined in claim 1 wherein said means for generating scan lines of video signal includes logic circuit means for determining the intensity of video signals at each bit position along the scan lines from three binary input signals from said bit map, including (1) the pixel signal corresponding to the current scan line, (2) the pixel signal corresponding to the line immediately above the current scan line, and (3) the pixel signal corresponding to the line immediately below the current scan line.
- Claim: 6. An apparatus as defined in claim 5 wherein the means for generating scan lines of video signal includes three FIFO circuits, three shift registers coupled to said FIFO circuits, and said logic circuit coupled to the output of said shift registers.
- Claim: 7. In a raster based laser beam imaging system having a predetermined normal DPI (dots per inch) resolution, and having a single laser beam making horizontal sweeps corresponding to said resolution, and using imaging materials having a predetermined threshold level, the improvement comprising
- Claim: means for energizing the laser beam at a rate to provide a higher number of dots per inch in the horizontal scan direction than said predetermined DPI;
- Claim: means for selectively creating predetermined, interleaved dots located at points between the horizontal scan lines of the laser beam by energizing said laser beam at two points on said scan lines directly above and below each predetermined desired interleaved dot, with the energization at one or both of said additional points on said scan lines being selectively below said threshold level, but with the cumulative energization at the interleaved predetermined point being greater than said threshold level so that dots appear at the predetermined interleaved points;
- Claim: said apparatus including means for producing a complete image at a higher resolution than said predetermined normal DPI with a single pass of said laser beam; and
- Claim: said apparatus including means for producing a laser beam which extends more than half way between adjacent scan lines.
- Claim: 8. An apparatus as defined in claim 7 wherein the means for energizing the laser beam includes means for providing digital signals representing the desired image with a resolution of twice said predetermined DPI.
- Claim: 9. An apparatus as defined in claim 8 wherein said means for generating video signals includes logic circuit means for determining the intensity of video signals at each bit position along the horizontal scan lines from three binary input signals from said bit map, including (1) the pixel signal corresponding to the current scan line, (2) the pixel signal corresponding to the line immediately above the current scan line, and (3) the pixel signal corresponding to the line immediately below the current scan line.
- Claim: 10. An apparatus as defined in claim 7 wherein the means for energizing the laser beam includes three FIFO circuits, three shift registers coupled to said FIFO circuits, and a logic circuit coupled to the output of said shift registers.
- Claim: 11. An apparatus for use with an image creation device such as a laser printer, the device including a body presenting an actuatable surface having image regions such as pixels defined thereon, and including a single selectively operable actuating means for actuating respective image regions for image creation and in order to present, for each actuated region, an actuated central zone surrounded by an actuated outer zone, said apparatus comprising
- Claim: control means for controlling the device actuating means in order to actuate a pair of vertically aligned image regions such that at least one of the respective central zones thereof is insufficiently actuated for substantial image creation while the respective outer zones cooperatively interact to form, between said respective central zones, an intermediate zone which is sufficiently actuated for image creation; with the energization of said actuating means being determined solely by the desired bit configuration of precisely three vertically aligned pixels;
- Claim: means for operably coupling said control means with the device actuating means;
- Claim: said apparatus including means for producing a complete image at a higher resolution than the normal resolution of said image creation device with a single pass of said actuating means; and
- Claim: said apparatus including means for providing an actuating means which extends more than half way between adjacent vertically spaced image regions.
- Claim: 12. The apparatus as set forth in claim 11, the image regions being actuatable by a beam of radiation such as laser light impinging thereon, the actuating means including means for selectively producing and directing a beam for impingement on and sweeping across each region during a predetermined sweep time period
- Claim: said control means further including means for modulating the beam directed for impingement on said pair of regions such that the beam impinges thereon for a time period sufficient to form said intermediate zone and for a time period less than the sweep time period.
- Claim: 13. The apparatus as set forth in claim 12, the image regions being configured to present a plurality of side-by-side image lines, said control means further including means for actuating respective image regions in adjacent ones of the image lines in order to present said pair of image regions.
- Claim: 14. The apparatus as set forth in claim 13, said adjacent ones of the image lines presenting an intermediate space therebetween, said control means further including means for forming said intermediate zone within said intermediate space.
- Claim: 15. The apparatus as set forth in claim 12, said control means further including means for processing said image data such that modulation data represents beam on-time for each image region.
- Claim: 16. Apparatus for enhancing the image produced by a scanning laser beam printer, said laser printer having a resolution comprised of a predetermined DPI (dots per inch) including parallel laser beam scan lines with the number of scan lines per inch corresponding to said DPI, and a predetermined DPI bit rate of energizing said laser beam along said scan lines, said laser beam being normally selectively energized, at said predetermined rate along said scan lines, at a predetermined dot-writing level sufficient to exceed a predetermined threshold of the imaging components and also determinative of the size of the image dots, said threshold being determinative of the presence or absence of dots on the laser printer image, and said laser printer also having means for accepting an external video signal that controls the energizing of said laser beam, said apparatus comprising
- Claim: means for providing digital signals corresponding to a double bit map having double DPI at least in the vertical direction of the desired image to be produced by said laser printer, said bit map having twice the predetermined DPI resolution of said laser printer; at least in the vertical direction;
- Claim: temporary storage means, coupled to receive said digital signals, for temporarily storing at least portions of three lines from said bit map, with one of said lines corresponding to a normal scan line of said laser printer and the other lines being the double DPI lines immediately above and below said scan line;
- Claim: logic means for decoding said three bits into up to five different values, each of said different values associated with one of a plurality of video pulse widths, some of said pulse widths being below said threshold level of said laser printer;
- Claim: means for generating scan lines of video signal with the same number of scan lines as said laser printer, said video signal comprised of consecutive pulses of said pulse widths corresponding to the decoded values associated with the combinations of said three bits, and at least some of said pulse widths being below the predetermined threshold level of said laser printer;
- Claim: said apparatus including means for producing a complete image at a higher resolution than said predetermined DPI with a single pass of said laser beam;
- Claim: 17. An apparatus as defined in claim 16 wherein a random access memory is provided for storing the bit map from which said digital signals are provided.
- Claim: 18. An apparatus as defined in claim 16 wherein said temporary storage means includes a plurality of random access memory FIFO circuits.
- Claim: 19. An apparatus as defined in claim 16 wherein said bit extracting means includes a plurality of shift registers.
- Claim: 20. An apparatus as defined in claim 16 including means for energizing said laser beam at a double DPI rate along said scan lines.
- Claim: 21. Apparatus for enhancing an image produced by a scanning beam marking engine, said marking engine having a nominal resolution comprised of a predetermined number of scan lines of a scanning beam of said marking engine, with each said scan line having a predetermined number of picture elements or pixels, said scanning beam normally being energized selectively at a predetermined rate along said scan lines to yield said predetermined number of pixels, said scanning beam energization being at a predetermined dot-writing level sufficient to exceed a predetermined threshold of imaging components included in said marking engine and also being determinative of a size of image dots, said threshold being determinative of a presence or absence of dots on an output image from the marking engine, said apparatus comprising
- Claim: means for producing digital signals corresponding to pixels, at a desired output resolution different from said nominal resolution, of a bit map of a desired image to be produced by said marking engine;
- Claim: temporary storage means, coupled to receive said digital signals, for temporarily storing a plurality of consecutive lines of said bit map;
- Claim: means for selecting a plurality of actuating signals for said marking engine, such that some of said actuating signals are below an imaging threshold of said marking engine, but are of sufficient intensity to produce an image dot between scan lines when adjacent points on successive scan lines are energized just below the imaging threshold;
- Claim: means for selecting a position at which said marking engine is capable of producing an imaging signals;
- Claim: means for extracting from said temporary storage means a sample subset having a predetermined number of pixels in a predetermined configuration, having said selected position in said marking engine which coincides with an approximate center of said predetermined number of pixels in a predetermined configuration, and with at least one of said pixels being spaced between scan lines of said marking engine;
- Claim: logic means for decoding the predetermined configuration of pixels and selecting a corresponding one of said actuating signals for said marking engine;
- Claim: means for generating actuating signals for said marking engine from the configuration of pixels;
- Claim: means for generating said scan lines from said actuating signals for said marking engine;
- Claim: said apparatus including means for producing a complete image at said different output revolution with a single pass of said beam; and
- Claim: said apparatus including means for producing a scanning beam which extends more than half way between adjacent scan lines.
- Claim: 22. An apparatus as defined in claim 21, wherein said desired output resolution is twice said nominal resolution.
- Current U.S. Class: 358/298; 346/108
- Current International Class: H04N 121
- Patent References Cited: 4437122 March 1984 Walsh et al. ; 4460909 July 1984 Bassetti et al. ; 4544264 October 1985 Bassetti et al. ; 4625222 November 1986 Bassetti et al. ; 4742363 May 1988 Shiraishi ; 4847641 July 1989 Tung ; 4864326 September 1989 Kawammura et al. ; 4873537 October 1989 Ohta ; 4879605 November 1989 Warkentin et al. ; 4933689 June 1990 Yoknis ; 5006704 April 1991 Mochizuki et al. ; 5017944 May 1991 Kitamura et al.
- Primary Examiner: Grimley, A. T.
- Assistant Examiner: Ramirez, Nestor R.
- Attorney, Agent or Firm: Poms, Smith, Lande & Rose
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