Colorimetric chart and color reproduction estimating device
AssigneeRicoh Company, Ltd.
InventorTakeshi Shibuya
Life of this patent
Estimating the term…
Abstract
A colorimetric chart, for measuring a color reproduction characteristic of an image forming apparatus, includes: a patch column that is arranged in a sub-scanning direction representing a conveying direction in which the image forming apparatus conveys the colorimetric chart and that is used in detecting periodic color fluctuation attributed to the image forming apparatus, wherein the patch column includes patches that are arranged in different phases on the same patch column.
Claims12
An apparatus for measuring a color reproduction characteristic of an image forming apparatus, comprising:
- a colorimetric device for measuring color reproduction characteristics data, the colorimetric device generates a colorimetric chart including a patch column that is arranged in a sub-scanning direction representing a conveying direction in which the image forming apparatus conveys the colorimetric chart and that is used in detecting periodic color fluctuation attributed to the image forming apparatus,
- wherein the patch column includes patches that are arranged in different phases on the same patch column,
- wherein the image forming apparatus that includes a photosensitive drum, and
- wherein the patch column includes a plurality of patches of different colors, and the plurality of patches are either arranged:
- in a repeating fashion according to a non-integral cycle of a ratio Rt between a drum cycle of the photosensitive drum and the patch cycle of the plurality of patches of different colors or,
- when the ratio Rt is approximated to an integer equal to or smaller than five, arranged in a repeating fashion according to a cycle of the ratio Rt and in different phases.
An apparatus for measuring a color reproduction characteristic of an image forming apparatus, comprising:
- a colorimetric device for measuring color reproduction characteristics data, the colorimetric device generates a colorimetric chart including a patch column that is arranged in a sub-scanning direction representing a conveying direction in which the image forming apparatus conveys the colorimetric chart and that is used in detecting periodic color fluctuation attributed to the image forming apparatus, wherein the patch column includes patches that are arranged in different phases on the same patch column,
- a color reproduction estimating device for estimating the color reproduction characteristic of the image forming apparatus that forms a color image on a printing medium by superimposing a plurality of basic colors based on image data, and
- an estimating unit:
- for converting, based on an internal parameter configured based on a measurement value obtained by measuring the patch color characteristic, the measurement value of the colorimetric patch area measured by the colorimetric device into an intermediate parameter that does not undergo a scale change due to concentration fluctuation, and
- for estimating, based on the intermediate parameter and the internal parameter, reproduced colors of the image forming apparatus, wherein:
- from a color attribute value included in the patch color characteristic measured by the colorimetric unit, the estimating unit,
- estimates phase, amplitude, and offset of a color attribute fluctuation component of a basic color synchronizing with a particular cycle, and
- corrects the intermediate parameter obtained by conversion from a patch input value of the colorimetric patch area.
Dependencies are inferred from the claim text.