Patent ID: 6042222
Filing Date: 2000-03-28
Classification: B41J

Abstract:
An inkjet printhead for ejecting ink droplets onto a print medium, said printhead comprising:a plurality of resistive elements for heating ink supplied from a reservoir to generate said ink droplets;a plurality of nozzles through which said ink droplets are ejected, with one nozzle associated with one resistive element;a plurality of firing chambers with one nozzle and one resistive element associated with one firing chamber, each one firing chamber enclosed on a side by a barrier, each one firing chamber having a base supporting said one associated resistive element, with said one associated nozzle above said one associated resistive element;a plurality of ink feed channels with one feed channel associated with one firing chamber, each one feed channel for supplying ink to said one associated firing chamber through a firing chamber entrance through said essentially enclosing barrier of said associated firing chamber, wherein for each said one feed channel a pair of opposed projections separated by a first width are formed in walls to said one feed channel to cause a constriction, wherein said walls converge along feed channel length toward the constriction at a first angle and diverge along feed channel length from the constriction toward the firing chamber at a second angle, wherein the first angle is equal to the second angle; andan ink refill channel operatively associated with said plurality of ink feed channels, the ink refill channel defined by an edge;wherein said plurality of resistive elements are grouped into sets, with resistive elements within a given set staggered at different distances from said edge, and wherein the first angle is prescribed as a function of the distance for the resistive element associated with a given feed channel.