Abstract: An ink jet print head (10) has a supply channel (14, 24, 52) connecting an ink source with an upper manifold (60U) and a lower manifold (60L). Each manifold has a tapered structure. From each manifold multiple inlet channels (36, 34, 44, 54) each lead to a respective pressure chamber (28) from which an outlet channel (40, 38, 46, 56, 62, 76, 82) leads to nozzles (88) from which droplets of liquid ink are expelled as a result of the action of a pressure transducer on the pressure chamber. Each manifold is separated from the supply channel by a baffle structure (92) that includes three baffles (94) formed by alternating plates (64, 78) having an open manifold with plates (58, 72) having a blocked manifold. The baffle structure reduces jetting nonuniformity by damping pressure displacement waves in the ink caused by the expulsion of ink droplets. The baffle structure also promotes effective heat transfer from the print head to ink being drawn in to the print head from the ink source.

Abstract: An image transfer ink-jet printer (10) employs an image receiving drum (12) that rotates relative to a ink-jet array print head (26) spanning the full width of the drum. An encoder disk (70) is coupled to the drum to coordinate ink drop ejection with precise angular rotational increments of the drum. The encoder disk has an alternating transparent/opaque pattern with a pitch that is one-half the desired resolution of the printer. A photo-optical detector (72) senses the alternating pattern and sends an asymmetrical signal to a duty-cycle correction circuit (140) that generates a symmetrical signal having a frequency double the one received from the photo-optical detector.