Maintaining black edge quality in liquid ink printing

A method of processing color image data for printing on an inkjet printer to maintain edge quality in an image recorded on a receiving medium, comprising:

• receiving color image data comprising a plurality of color planes, the color planes including at least one black plane and at least one non-black plane, wherein each color plane comprises an array of separation pixels, each separation pixel having at least three states, a first state corresponding to depositing no ink, a second state corresponding to depositing one ink drop, and a third state corresponding to depositing more than one ink drop;
• identifying an interface between a black area and a non-printed area;
• defining an N-Dixel wide border within the black area;
• modifying the color image data corresponding to the N-pixel wide border to set substantially all the separation pixels in the black plane to the second state.

A method of processing color image data for printing on an inkjet printer to maintain edge quality in an image recorded on a receiving medium, comprising:

• receiving color image data comprising a plurality of color planes, the color planes including at least one black plane and at least one non-black plane, wherein each color plane comprises an array of separation pixels, each separation pixel having at least three states, a first state corresponding to depositing no ink, a second state corresponding to depositing one ink drop, and a third state corresponding to depositing more than one ink drop;
• identifying an interface between a black area and a non-printed area;
• defining an N-pixel wide border within the black area;
• modifying the color image data corresponding to the N-pixel wide border to set substantially all the separation pixels in the black plane to a selected pixel state;
• identifying an interface between a color area and a non-printed area;
• defining an M-pixel wide border region within the color area;
• and
• modifying the color image data corresponding to the M-pixel wide border region to set substantially all the separation pixels in a first non-black plane to a selected pixel state.

A method of processing color image data for printing on an inkjet printer to maintain edge quality in an image recorded on a receiving medium, comprising:

• receiving a target pixel comprising multiple separation pixels, each separation pixel being associated with a separate color plane and having at least three states, a first state corresponding to depositing no ink, a second state corresponding to depositing one ink drop, and a third state corresponding to depositing more than one ink drop;
• determining if the target pixel is within a black border region near a black/non-printed interface, and if so, setting the separation pixel associated with a black color plane to a selected black pixel state;
• and
• determining if the target pixel is within a color border region near a black/non-printed interface;
• and if so, setting the separation pixels associated with the non-black color planes to a selected color pixel state.

A device for processing color image data to maintain edge quality in an image recorded on a receiving medium, comprising:

• a black window filter connected to receive a first set of pixels including a target pixel comprising multiple separation pixels, each separation pixel being associated with a separate color plane and having at least three states, a first state corresponding to depositing no ink, a second state corresponding to depositing one ink drop, and a third state corresponding to depositing more than one ink drop, the black window filter generating a black statistics signal;
• a pixel identification circuit connected to receive the black statistics signal, the identification circuit generating a pixel identification signal indicating whether the target pixel is within a black border region near a black/non-printed interface;
• a pixel modification circuit connected to receive the pixel identification signal, the modification circuit filtering the target pixel to set the separation pixel associated with a black color plane to a selected black pixel state;
• and
• a color statistics collection filter operating on a second set of pixels including the target pixel, the color statistics collection filter generating a color statistics signal;
• wherein the pixel identification signal further indicates whether the target pixel is within a color border region near a color/non-printed interface;
• and
• wherein the pixel modification circuit filters the target pixel to set the separation pixels associated with the non-black color planes to a selected color pixel state.

A method of processing color image data for printing on an inkjet printer to maintain edge quality in an image recorded on a receiving medium, comprising:

• receiving a target pixel comprising multiple separation pixels, each separation pixel being associated with a separate color plane and having at least three states, a first state corresponding to depositing no ink, a second state corresponding to depositing a first volume of ink, and a third state corresponding to depositing a second volume of ink, the second volume being greater than the first volume;
• determining if the target pixel is within a black border region near a black/non-printed interface, and if so, setting the separation pixel associated with a black color plane to a selected black pixel state;
• and
• determining if the target pixel is within a color border region near a black/non-printed interface;
• and if so, setting the separation pixels associated with the non-black color planes to a selected color pixel state.

A method of processing color image data for printing on an inkjet printer to maintain edge quality in an image recorded on a receiving medium, comprising:

• receiving color image data comprising a plurality of color planes, the color planes including at least one black plane and at least one non-black plane, wherein each color plane comprises an array of separation pixels, each separation pixel having at least three states, a first state corresponding to depositing no ink, a second state corresponding to depositing one ink drop, and a third state corresponding to depositing more than one ink drop;
• identifying an interface between a black area and a non-printed area;
• defining an N-pixel wide border within the black area;
• modifying the color image data corresponding to the N-pixel wide border to set substantially all the separation pixels in the black plane to a selected pixel state;
• identifying an interface between a color area and a non-printed area;
• defining an M-pixel wide border region within the color area;
• and
• modifying the color image data corresponding to the M-pixel wide border region to set substantially all the separation pixels in a first non-black plane to a selected pixel state.