Hewlett-packard Company

Hewlett-packard Development Company, L.P.

Alpha N Doan

Darren W Wilcox

Mark S Hickman

Dennis Sonnenburg

Brent W Richtsmeier

Jack H Schmidt

Craig A Maurer

Jon Lee Zimmerman

Scott F Williams

Peter C Morris

Paul J Wield

Curt N Torgerson

Anthony D Parkhurst

Lawrence W Chan

A dust tolerant scanner without a transparent plate to support objects scanned by its media scan assembly. Other dust or debris collecting surfaces in the optical path of the scanner are positioned as far away as possible from an object focal plane of the media scan assembly. The media scan assembly includes upper and lower document feeder portions which define a media path adjacent to a reference surface of the upper portion. The lower document feeder portion includes a media conformance member which positions pieces of media against the reference surface as the pieces of media are advanced along the media path. The media conformance member includes ramp portions and an aperture which provides an optical path between the object focal plane and a sensor focal plane within the scanner.

Dust tolerant windowless scanner

In a scanning unit such as a facsimile machine, an automatic document feeder transports individual sheets from a stack of documents along a document path over a scanning window to an output tray. An upper guide member includes an integrated chassis which provides most of the functional features required for picking individual sheets from a stack of documents in an input tray and transporting the sheet past a scanning window. The various components incorporated in the integrated chassis include a document separation mechanism, pre-scanning pinch rollers, post-scanning pinch rollers, a spring-loaded limiter with minimal paper path obstruction, a hinging mechanism to facilitate manual access to the document path, a latching mechanism, referencing datums, and ESD grounding including ESD brushes adjacent the document path and an ESD shield for a circuit board housed in the upper guide member. In the preferred form, the integrated chassis is formed from an enlarged sheet metal plate which attaches to the underside of a manual control/display panel with the circuit board sandwiched therebetween.

Integrated chassis for automatic document feeder in a scanning unit

A color ink jet printer including a print carriage movable along a carriage scan axis, a plurality of non-black color printing ink jet printheads supported by the print carriage and offset relative to each other so that their nozzle arrays are non-overlapping along the media scan axis, and a black printing ink jet printhead having a nozzle array that overlaps along the media axis with one of the nozzle arrays of the non-black color printing ink jet printheads, whereby as the carriage is scanned along the carriage scan axis the nozzle arrays of the non-black color printing ink jet printheads traverse non-overlapping print regions and the nozzle array of the black printing printhead traverses a print region that overlaps one of the non-overlapping print regions traversed by the nozzle arrays of the non-black color printing ink jet printheads.

Ink jet painter having staggered nozzle array for color printing

Ink-jet images are improved by printing groups of adjacent pixels with clusters of overlapping ink drops for resisting random ink drop coalescence that would lead to a mottled image.

Ink drop placement for improved imaging

In a scanning unit such as a facsimile machine, an automatic document feeder transports individual sheets from a stack of documents along a document path over a scanning window to an output tray. An upper guide member includes an integrated rigid chassis for positioning document control components adjacent the scanning window. The document control components included a central pre-scanning pinch roller, a full width hold-down limiter, and a central post-scanning pinch roller which are each mounted with their own separate biasing springs on the integrated chassis. Two elongated wire springs respectively engage both ends of the hold-down limiter, while two sets of cantilever leaf springs provide strong and weak spring biasing, respectively, to the pre-scanning and post-scanning pinch rollers.

Scanning unit with independent spring-loaded document control components

A color ink jet printer including a print carriage movable along a carriage scan axis and a plurality of color producing ink jet printheads supported by the print carriage and offset relative to each other so that their nozzle arrays are non-overlapping along the media scan axis, such that the nozzle arrays of the ink jet printheads traverse non-overlapping regions as the carriage is scanned along the carriage scan axis.

Staggered pens in color thermal ink-jet printer

Quality of printed images as produced by an ink-jet printer (10) is improved by staggering applications of ink dots (30) to pixel locations (36) such that overlapping ink dots are printed on successive passes of a printhead (16) and such that swaths (38) are partially printed on overlapping passes of the printhead. Quality of multi-colored or multi-shaded images is further improved by grouping pixels (36) into super pixels (42), and applying various combinations of colored ink dots to the various pixels within each super pixel in a staggered sequence.

Interlace printing process

A retractable pin sprocket drive for feeding paper employs free floating, radially moving, cam actuated sprocket pins in axially spaced sprocket hubs forming sprocket wheels. The pins are slidably fitted in equally angularly spaced radial slots in each sprocket hub. The sprocket wheels are each journalled in a sprocket wheel housing and the sprocket pins are moved radially only by a stationary cam track in each sprocket housing as the sprocket wheels rotate. Insertion of paper having perforated edges is facilitated by means providing for the precise axial spacing of the sprocket wheels and angular positioning of the sprocket wheels and pins in relation to the perforations or holes along the edges of the paper, together with transparent sprocket wheel housings and openings therethrough permitting viewing of the sprocket pins and the holes in the paper as they come together, to permit precise sprocket pin insertion into the holes in the paper.

Growing community of inventors

San Diego, CA, United States of America

Alpha N Doan