Non-printing patterns for improving font print quality

摘要

Utilization of non-printing high-spatial-frequency auxiliary pixels are introduced into the bitmap of a font to obtain local control of the text image development by modification of local average voltage in the development nip. These auxiliary pixels embody frequencies or levels of charge that are past the threshold for printing on the Modulation Transfer Function (MTF) curve, and therefore by themselves result in no toner deposition on the resultant page. These auxiliary pixels will however, position the toner cloud by modulating it and compensate for cleaning field and toner supply effects. This will better position the toner cloud to ensure adequate toner supply to all parts of the font so that the desired printing pixels will print as intended.