Patent ID: 8333459

Claim:
A printing device ( 10 ), comprising: a substrate ( 22 ) including an aperture ( 20 ) extending therethrough that defines a slot formed into said substrate and wherein said slot includes a mechanical strengthening structure ( 28 ) extending across an expanse of said aperture, wherein said aperture includes a side wall ( 46 ) and defines a liquid ink flow path; an ink firing chamber ( 24 ) including interior wall surfaces ( 52 ) that define a firing channel ( 34 ) that terminates in a firing orifice ( 36 ) fluidically connected to said aperture; and a coating ( 50 ) positioned on said side wall of said aperture and positioned on all of said interior wall surfaces of said firing channel, said coating being impervious to etching by liquid ink ( 42 ), and wherein said coating is chosen from one of silicon dioxide, aluminum oxide, hafnium oxide, silicon nitride, a conformal polymer formed from a gas phase monomer, an organic polymer, a plated metal chosen from one of nickel, gold and palladium, silicon carbide, and a combination thereof.