Method and apparatus for reducing the size of drops ejected from a thermal ink jet printhead

The volume of drops ejected from thermal ink jet printheads varies with the temperature of the printhead. 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 light...

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Bibliographische Detailangaben
Hauptverfasser:	YEUNG, KING-WAH W, HOLSTUN, CLAYTON, CANFIELD, BRIAN
Format:	Patent
Sprache:	eng
Schlagworte:	CORRECTION OF TYPOGRAPHICAL ERRORS i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME LINING MACHINES PERFORMING OPERATIONS PRINTING SELECTIVE PRINTING MECHANISMS STAMPS TRANSPORTING TYPEWRITERS
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Beschreibung
Zusammenfassung:	The volume of drops ejected from thermal ink jet printheads varies with the temperature of the printhead. 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 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.