Method and apparatus for the control of thermal ink jet printers.

摘要

The volume of drops ejected from thermal ink jet printheads varies with the temperature of the printhead (20). The variation in drop volume degrades print quality by causing variations in the darkness in black and white text, the contrast of gray scale images, and variations in the chroma, hue, and lightness of color images. The present invention reduces the range of drop volume variation by reducing the range of printhead (20) temperature variation during the print cycle by keeping the printhead temperature above a reference temperature. When the printhead temperature falls below the reference temperature during a print cycle the printhead is heated with nonprinting pulses. <IMAGE>