Printer nonuniformity compensation for halftone screens

A method for providing gain control to light emitting pixels of a printer depending on a particular type of halftone screen selected from a group of halftone screens comprising:

• providing a print head having a plurality of different light sources wherein each light source can produce different levels of light, an electronic version of each halftone screen, and a plurality of stored gain control adjustment signals for each light source based upon the light output of that light source;
• selecting a particular hard copy test target halftone image corresponding to the electronic version of a selected screen;
• and
• scanning the selected hard copy test target halftone screen and providing data representing differences in density between the hardcopy test target and the electronic version of the selected screen;
• producing adjusted gain control signals for each of the different light sources for the selected halftone screen based upon the density-difference data;
• and
• repeating the selecting through producing steps for each halftone screen in the group of halftone screens.

A method for providing gain control to light emitting pixels of a printer depending on a particular type of halftone screen selected from a group of halftone screens comprising:

• providing a print head having a plurality of different light sources wherein each light source can produce different levels of light, an electronic version of each halftone screen, and a plurality of stored gain control adjustment signals for each light source based upon the light output of that light source;
• selecting a particular hard copy test target halftone image corresponding to the electronic version of a selected screen;
• and
• scanning the selected hard copy test target halftone screen and providing data representing differences in density between the hardcopy test target and the electronic version of the selected screen;
• producing first adjusted gain control signals for each of the different light sources for the selected halftone screen from the stored gain control adjustment signals based upon the density-difference data;
• receiving a screen correlation factor corresponding to one of the halftone screens in the group other than the selected screen;
• and
• producing second adjusted gain control signals from the first adjusted gain control signals for the one of the halftone screens based upon the received screen correlation factor for the one of the halftone screens.