Patent ID: 7946691

Claim:
A printhead comprising: a nozzle array having a width; a gas flow source; and a gas flow duct in fluid communication with the gas flow source, the gas flow duct including an expansion region and a compression region, the expansion region having a cross sectional length and a cross sectional width, the expansion region including a first portion and a second portion, the first portion of the gas flow duct being coupled to the gas flow source, the expansion region of the gas flow duct gradually expanding along its cross sectional length to at least the width of the nozzle array such that the cross sectional width of the expansion region in the second portion of the expansion region is greater than the cross sectional width of the expansion region in the first portion of the expansion region, the compression region having a cross section sectional length and a cross sectional width, the compression region including a third portion and a fourth portion, the third portion of the compression region being adjacent to the second portion of the expansion region, the compression region of the gas flow duct gradually contracting along its cross sectional length such that the cross sectional width of the compression region in the fourth portion of the compression region is less than the cross sectional width of the compression region in the third portion of the compression region.