Abstract: A full color copier having an inkjet printer includes a controller and algorithm for switching automatically intra page between one of two independent high speed carriage velocities and between one of two independent pen firing frequencies for maximize throughput relative to low ink density and high ink density graphic images to improve print quality images having densely inked areas by substantially reducing ink pen starvation, droplet trajectory errors, and fuzzy text edges.

Abstract: Two printing-medium guide systems restrain the medium. One is in an area upstream (along the direction of medium advance) from the pen, and extending laterally across the width of the medium except in one or more regions laterally near the engagement of a print-medium advancing device. The other guide system is disposed laterally from the pen, and extends laterally across the medium only in one or more regions laterally near the engagement of the advancing device. Preferably these "one or more regions" are only near the lateral edges of the medium--so that (1) the first guide system restrains the medium over an area that stops short (ideally about 11/2 centimeter short) of the lateral edges; and (2) the second guide system is bifurcated, disposed laterally in two directions from the pen, and restrains the medium across only the lateral edges of the medium (most preferably in a strip whose width is a few millimeters, ideally 3 mm).

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.

Abstract: An ink-jet printer having improved print quality and full color printing capability on plain paper media. To accommodate placement of both input and output media trays on the same side of the printer housing for operator convenience, a paper path with a direction reversal is employed. A paper preconditioning preheater with a curved surface and a multi-purpose paper path component accomplish the direction reversal. The printer further includes a manual feed path for guiding a manually fed sheet or envelope from a manual feed inlet slot at the top, rear corner of the printer to a path converging location with the primary feed path. The preheater includes a heating portion disposed along the primary path between the path converging location and the-print area, to provide the capability of preheating media fed either from the input tray or the manual feed slot.

Abstract: A graduated, highly tensioned metallic codestrip is used in a large-format automatic image-related device such as a D-size or larger plotter, yielding positional precision even better than those of prior small-format devices. Preferably perforations in the strip are the graduations, used in determining position of a carriage that holds image transducers (e. g., pens). The strip passes through a slot (open along one edge, closed at the other) in a perforation sensor. The image transducers are very close to the slotted sensor and the strip, to minimize the effect of disturbances arising between the strip and transducers. Two unperforated portions of the strip--one relatively broad, and another relatively narrow border portion--provide very good structural stability for the tensioned strip. Stability under tension is enhanced by wrapping the strip partway around a stanchion at each end.