2-D image based correction of thermal ghosting in a digital printer
AssigneeXerox Corporation
InventorsJack T. Lestrange, Palghat S. Ramesh, Joseph C. Sheflin
Life of this patent
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Abstract
An image based correction system compensates for the image quality artifacts induced by thermal ghosting. With thermal ghosting directly tied to previous image content, a feed forward control system predicts the thermal ghosting artifact based on the images previous printed and generates an open loop, 2-D correction to the gray-level image that mitigates the undesirable ghosting artifacts. For example, the correction system compensates for the thermal ghosting by making the current digital image “lighter” in areas that will be imaged onto warmer blanket regions, thereby cancelling out TRC differences between different temperature regions.
Claims20
A method for printing a plurality of images with an ink-based digital image forming device having a rotatable imaging member with a reimageable surface in an environment having an ambient temperature, the plurality of images including a current digital image and a previously printed image, the method comprising:
- a) aligning information of the current digital image with a temperature map of the reimageable surface where the current digital image will be rendered, the information including a pixel-wise gray level of the current digital image, the temperature map representing temperature increases on the reimageable surface caused by formation of the previously printed image on the reimageable surface;
- b) determining a corrected current digital image including a gray level modification of the current digital image based on the pixel-wise gray level of the current digital image and the temperature map to decrease marking material density at reimageable surface discrete coordinates that are warmer than a reference temperature and prevent ghosting of the previously printed image on a printing of the current digital image;
- and
- c) rendering the corrected current digital image on the reimageable surface for a printing by the ink-based digital image forming device, the printing of the rendered corrected current digital image appearing not as the corrected current digital image, but as the current digital image.
An image formation apparatus for printing a plurality of images with an ink-based digital image forming device having a rotatable imaging member with a reimageable surface in an environment having an ambient temperature, the plurality of images including a current digital image and a previously printed image, comprising:
- a controller;
- and
- a storage device coupled to the controller, the storage device having instructions operative on the controller to
- a) align information of the current digital image with the temperature map of the reimageable surface where the current digital image will be rendered, the information including a pixel-wise gray level of the current digital image, the temperature map representing temperature increases on the reimageable surface caused by formation of the previously printed image on the reimageable surface;
- b) determine a corrected current digital image including a gray level modification of the current digital image based on the pixel-wise gray level of the current digital image and the aligned temperature map to decrease marking material density at reimageable surface discrete coordinates that are warmer than the background area and prevent ghosting of the previously printed image on a printing of the current digital image;
- and
- c) instruct the ink-based digital image forming device to render the corrected current digital image on the reimageable surface for a printing by the ink-based digital image forming device, the printing of the rendered corrected current digital image appearing not as the corrected current digital image, but as the current digital image.
A method for printing a plurality of images with an ink-based digital image forming device having a rotatable imaging member with a reimageable surface in an environment having an ambient temperature, the plurality of images including a current digital image and a previously printed image, the method comprising:
- a) creating a temperature map of the reimageable surface based on temperature increases above a reference temperature for a plurality of reimageable surface discrete coordinates on the reimageable surface, the reference temperature associated with a temperature setpoint of a central drum chilling system, the temperature increases for the plurality of reimageable surface discrete coordinates resulting from formation of the previously printed image on the reimageable surface;
- b) aligning information of the current digital image with the temperature map of the reimageable surface where the current digital image will be rendered, the information including a pixel-wise gray level of the current digital image;
- c) determining a corrected current digital image including a gray level modification of the current digital image based on the pixel-wise gray level of the current digital image and the aligned temperature map to decrease marking material density at reimageable surface discrete coordinates that are warmer than the background area and prevent ghosting of the previously printed image on a printing of the current digital image;
- and
- d) rendering the corrected current digital image on the reimageable surface for a printing by the ink-based digital image forming device, the printing of the rendered corrected current digital image appearing not as the corrected current digital image, but as the current digital image.
Dependencies are inferred from the claim text.