Method for black pixel designation in document image data

A printer driver comprising:

• a raster mechanism configured to convert all vector objects into bitmap data for printing, including a black extractor configured to replace all composite black pixels in the vector objects with true black pixels;
• a color object locator configured to identify all color vector objects of all the respective vector objects that include color and to identify all near-color black vector objects of all the respective vector objects that are positioned alongside, but not in contact with, the identified color vector objects;
• and
• a black extraction switch configured to suspend operation of the black extractor for all composite black pixels in the identified color vector objects and the identified near-color black vector objects to maintain their designation as composite black pixels to enable half-tone printing as a portion of true black ink and a portion of composite black ink.

A printer comprising:

• an ink supply including a color ink reservoir and a black ink reservoir;
• a printhead in fluid communication with the ink supply and including a single orifice plate;
• a printer driver stored in memory and configured to convert vector objects in document image data from a raster format into a bitmap format for printing with all black portions being designated as composite black pixels and with the printer driver including:
• a black extractor configured to replace all composite black pixels in the vector objects with true black pixels;
• a color object locator configured to identify, in the document image data, color objects that include color and to identify near-color objects that are positioned to border color objects or that are positioned alongside, but spaced apart form, color objects;
• and
• a black extraction switch configured to maintain a composite black pixel designation for all black pixels in the identified color objects and the identified near-color objects without conversion to a true black pixel via the black extractor of printer driver.

A printer driver comprising:

• means for converting text objects, and graphics objects in document image data into bitmap data for printing, including means for designating all black portions in the text objects and in the graphics objects as composite black pixels and means for selectively replacing composite black pixels with true black pixels;
• means for identifying, among the respective converted text objects and converted graphics objects in the document image data, color text objects and color graphics objects that include color pixels, respectively, and for identifying color-overlap text objects and color-overlap graphics objects that overlap color objects, respectively;
• and
• means for blocking performance, of the means for selectively replacing composite black pixels, to maintain all black pixels as composite black pixels in the identified color text objects, identified color graphics objects, identified color-overlap text objects, and identified color-overlap graphics objects.

A computer-readable medium having computer-executable instructions for performing a method of processing document image data for printing, the method comprising:

• rasterizing all objects in the document image data into a bitmap format including converting all black portions of the respective objects into composite black pixels;
• identifying, among all the respective objects in the document image data, color objects that contain color and color-border black objects that omit color while bordering color objects;
• maintaining all composite black pixels in the identified color-border black objects as composite black pixel designations without substitution to true black pixels;
• and
• generating print data in which the composite black pixel designations are to be half-tone printed on a print medium as a portion of composite black ink and a portion of true black ink.