Ink jet printing apparatus and method providing an induced clean-air region

Abstract From the Canadian patent

To protect critical operative portions (e.g. the orifice plate) of ink jet printing apparatus from airborne debris particles (e.g. paper dust) a wall is, provided to substantially enclose a region around those critical operative portions and filtered air is induced to flow through the enclosed region from a location proximate the operative portions to a droplet outlet. In one mode the energy of printing droplet streams induces the air flow. In another embodiment the energy of printing substrate movement induces the air flow.