Abstract: An ink jet array print head (101) includes four media-width linear ink jet arrays (100). Ink flows from four sets of manifolds (106) through acoustically matched inlet filters (116), inlet ports (117), inlet channels (118), pressure chamber ports (120), and ink pressure chambers (122). Ink leaves the pressure chambers through outlet ports (124) and flows through oval outlet channels (128) to orifices (108), from which ink drops (110) are ejected. The ink pressure chambers are bounded by flexible diaphragms (130) to which piezo-ceramic transducers (132) are bonded. To minimize inter-jet cross-talk caused by pressure fluctuations in the manifolds, compliant walls (150) form one wall along the entire length of each manifold. An improved ink feed system (210) supplies four colors of ink to the print head.

Abstract: A method of cleaning a media preheater that is positioned in the media path of a printer is disclosed. The media preheater has a fixed heater and a movable plate array biased toward the heater such that printer media passing between the plate array and the heater is compressed therebetween and heated. The preheater may be positioned upstream of a print head and downstream of a media advancing mechanism in the media path. More than one plate may be provided in the plate array to accommodate non-planarity of the heater or the printing media. The method elevates the temperature of the contact surface of the preheater to a cleaning temperature that is greater than the operating temperature and then passes a chase sheet over the surface to remove contamination from the preheater surface.

Abstract: A media preheater positioned in the media path of a printer and having a fixed heater and a movable plate array biased toward the heater such that printing media passing between the heater and the plate array is compressed therebetween and heated. The preheater may be positioned upstream of a print head and downstream of a media advancing mechanism in the media path. More than one plate may be provided in the plate array to accommodate non-planarity of the heater or the printing medium. The plate array may be a thermally massive element that contacts the heater when no media is present, thereby permitting the medium to be heated from both sides.

Abstract: An improved media-width phase-change ink-jet print had (102) maintains a uniform temperature across its width to produce consistent drop mass and uniform print quality. The print head uses a heater (120) including two separately controlled, overlapping heating zones (154). The heating zones produce heat gradients (170, 172) that have maximum outputs toward opposing edges (168a, 168b) of the print head and are controlled in response to thermistors (138s, 168b) positioned at the corresponding edges. The two heating zones together produce a linear heat gradient (180) across the print heat to compensate for uneven head-to-drum spacing (166) and other unsymmetrical thermal loads on the print head. The improved print head also includes baffles (192) that reduce air flow between the head and the attached reservoir (118), and thermal breaks (218) that insulate the section (220) of the head that includes the jets from the thermal gradients at the edges of the print head.