Loading patent…
AssigneeXerox Corporation
InventorsFred F. Hubble III, Tonya L. Love, Daniel A. Robbins
Estimating the term…
An improved and lower cost color spectrophotometer, especially suitable for an on-line color printer color control system, in which plural different spectra LEDs sequentially perpendicularly illuminate a common and substantially circularly illuminated color test area, which may be variably spaced and variably oriented relative to the spectrophotometer, through a common central lens system, and also the reflected illumination therefrom may be measured at 45 degrees thereto by averaging the outputs of photodetectors spaced around that circularly illuminated color test area, to provide reduced sensitivity to the variable angular or azimuthal orientation of the color test area relative to the spectrophotometer, and which photodetectors may be so illuminated by 1:1 optics for spatial insensitivity.
A color correction system for a color printer having an output path for moving printed color sheets, including printed test sheets with printed color test patches, in which a spectrophotometer is mounted adjacent to said printer output path for sensing the colors printed on said printed color test patches on said printed test sheets as said printed test sheets are moving past said spectrophotometer in said output path, said color correction system including plural illumination sources for sequentially illuminating said color test patches with different illumination spectra in a substantially circular illumination pattern, and a plural photodetectors system for providing electrical output signals in response to the color of said test patches from said sequential illumination of said test patches by reflection of said illumination of said color test patches in said substantially circular illumination pattern by said illumination sources, and a lens system for transmitting said reflected illumination from said color test patches to said plural photodetectors system, so as to provide improved angular displacement insensitivity of said spectrophotometer relative to said printed test sheets.
A color correction system for a color printer having an output path for moving printed sheets, including printed test sheets with printed color test patches, in which a spectrophotometer is mounted adjacent to said printer output path for sensing the colors printed on said printed color test patches on said printed test sheets as said printed test sheets are moving past said spectrophotometer in said output path, said spectrophotometer being adapted to measure the colors of said printed color test patches on said printed test sheets while said moving printed test sheets are variably angularly oriented relative to said spectrophotometer, said spectrophotometer comprising plural illumination sources for sequentially projecting plural different spectral illuminations from said plural illumination sources substantially perpendicular to said printed color test patches to illuminate said color test patches, and plural photodetectors angularly spaced from said illuminated color test patches to angularly receive reflected illumination therefrom from different directions, so as to provide reduced angular displacement sensitivity of said spectrophotometer relative to said color test patches.
A method of color correction for a color printer having an output path for moving printed sheets including printed test sheets with printed color test patches, in which a spectrophotometer is mounted adjacent to said printer output path for sensing the colors printed on said printed color test patches on said printed test sheets as said printed test sheets are moving past said spectrophotometer in said output path, said spectrophotometer being adapted to measure the colors of said printed color test patches on said printed test sheets while said moving printed test sheets are variably angularly oriented relative to said spectrophotometer to provide a broad spectrum color measurement of said color test patches, comprising substantially perpendicularly sequentially illuminating a substantially circular area of said color test patches with a limited plural number of different spectra illuminations, and sequentially non-contact measuring reflected illumination from said sequentially illuminated substantially circular area of said color test patches at approximately 45 degrees thereto with at least one photodetector spaced from said color test area to provide reduced angular sensitivity of said photodetector relative to said color test patches.
A method of color correction for a color printer having an output of printed sheets including printed test sheets with printed color test patches, in which a non-contacting spectrophotometer measures the colors of said printed color test patches on said printed test sheets, wherein said color test patches are substantially perpendicularly illuminated in a substantially circular illuminated area of said color test patches sequentially with a limited plural number of different spectra illuminations, and the angularly reflected illumination from said sequentially substantially circularly illuminated color test patch areas is measured by applying said angularly reflected illumination simultaneously to plural photodetectors spaced around said illuminated area and providing averaged output signals from said photodetectors for reduced variable angle positioning sensitivity of said color test patches relative to said non-contacting spectrophotometer.
A color correction system for a color printer comprising means for substantially perpendicularly sequentially illuminating a substantially circular color test area of printed test sheets with a limited plural number of different spectra illuminations, and means for sequentially measuring the angularly reflected illumination from said sequentially illuminated substantially circular illuminated color test area by applying said angularly reflected illumination simultaneously to plural photodetectors spaced around said color test area and summing the outputs of said plural photodetectors to provide an averaged output.
Dependencies are inferred from the claim text.