Patent ID: 6130693
Filing Date: 2000-10-10
Classification: B41J

Abstract:
An ink jet printhead which prevents accumulation of air bubbles therein, comprising:a heater plate having on one surface thereof an array of heating elements, addressing circuitry means, and electrical leads for the selective application of electrical pulses to each of the heating elements, each of the selectively applied pulses ejecting an ink droplet from the printhead; anda planar structure having a plurality of ink flow directing channels with substantially equal cross-sectional areas and opposing ends, the channels having one end open and the other end in fluid communication with an ink reservoir, the reservoir having an ink inlet and providing an ink supply from which the channels are capillarily refilled when ink droplets are ejected from the printhead, the reservoir having a cross-sectional area in an orientation substantially perpendicular to the ink flow direction therethrough, which, is substantially equal to the total cross-sectional areas of the plurality of the channels in the ink flow direction, thereby providing an ink volume in the reservoir which is sufficiently low to prevent the ink therein from residing for a relatively long time period during a printing operation and maintaining a relatively high ink flow rate through the reservoir during a printing operation, so that air bubbles, formed during the droplet ejection process are removed with subsequent droplet ejections.