Thin, shallow-angle serrated hold-down with improved warming, for better

Abstract

The invention minimizes liquid-ink deposition on the top and edge of a guide-plate (or 'hold-down' plate), and also minimizes running of deposited liquid ink along the top to the edge. Through these two effects together the rate of ink deposition on the top and edge of the plate is held below the volume of ink per unit time that can dry there. The invention also minimizes ink transfer from the edge onto the print medium. The deposition-minimizing provisions include two features: serration, and a very fine vertical dimension of the edge itself. These features enhance air flow, and thus transport of ink spray, rapidly across the edge--discouraging formation of a dead-air zone from which spray readily precipitates onto the edge. The thin edge also presents a smaller direct target for ink droplets. The serrations may enhance transport by (1) promoting a more-favorable balance between laminar and turbulent flow; or (2) enabling air passage between opposed surfaces of the plate--from underside to top surface--creating an updraft to lift the flow away from the edge; or (3) both. To minimize running of liquid ink along the plate, the plate is mounted essentially all exposed to heat from a heater whose main purpose is drying ink on the print medium: this raises the plate temperature and so promotes drying of ink on the plate too. To further minimize running of liquid ink along the plate toward the edge, the edge panel is at a very shallow angle; and the air-flow provisions mentioned above also help carry away liquid carrier, from whatever ink does fall onto the edge, thus accelerating drying. To minimize brushing off even a slight accumulation of ink (liquid or dry) onto the medium, the serrations also raise most of the edge away from the medium.