Hewlett-packard Development Company, L.P.

Hewlett-packard Company

Vance M Stephens

Steve Orrin Rasmussen

Robert M Yraceburu

Steven P Downing

Dan Arquilevich

Victor Bruhn

Stuart Douglas Spencer

Jason S Belbey

Allan G Olson

William Richard Huseby

Peter J Boucher

David W Pinkernell

Jim Beehler

A difference in feed roller diameter from one printer to another causes a media to advance by a different amount for a given rotation of a drive shaft to which the feed roller is coupled. Such variation in advance distance is a linefeed error. Mean linefeed error is determined and corrected by printing a test plot having several areas. Each area is formed of the same image pattern, but is printed at a different linefeed error adjustment to compensate for mean linefeed error. The different adjustments are prescribed and span a typical compensation range for a given print engine model. The different adjustment factors cause banding to occur in some areas. The user picks one of the test pattern areas which has the highest print quality (i.e., least or no banding). The linefeed adjustment factor corresponding to such area is used for normal printing.

Method for adjusting drive roller linefeed distance

Techniques for printing an image on a print medium. Information regarding the actual size of the medium, or the actual placement of the medium at a print zone, is used to shift the image to properly align the image on the medium. The image can be shifted digitally, or by movement of the medium relative to the printing element.

Techniques for aligning images using page characteristics and image shifting

In an inkjet printing apparatus an inkjet printhead has a plurality of inkjet nozzles which eject ink onto media located within a print-zone. A drive shaft is located upstream of the printhead and is incrementally rotated to advance the media. The drive shaft has a longitudinal axis, a first radius over a central length and a second radius less than the first radius at a first recess and a second recess, each said recess being peripheral to the central length. A plurality of pinch devices stabilize the media against the drive shaft. A first guide is aligned with the first recess and is spaced from an axis of the drive shaft by a first distance which is less than the first radius. A second guide is aligned with the second recess and is spaced from the axis by a second distance less than the first radius.

Controlling media curl in print-zone

A holddown for a hard copy device comprises a member having a surface and plural vacuum zones. Each of the vacuum zones defines a cavity in the surface having at least one port therethrough, and each cavity is defined by a sidewall circumscribing the cavity. At least one of the cavities has sidewall with a first section at a first height relative to the surface and a second section at a second height relative to the surface.

Holddown for a hardcopy device

A vacuum platen assembly for a fluid-ejection device of one embodiment of the invention is disclosed includes a platen that has a number of vacuum holes. Each of at least one of the vacuum holes has sidewalls with anti-clog profiles at least substantially prevent collection of media debris and aerosol on the sidewalls.

Vacuum platen assembly for fluid-ejection device with anti-clog vacuum hole sidewall profiles

A printing mechanism comprises a print engine that prints an image on a first side of a photographic print media, a laminator that laminates the first side of said photographic print media having said image printed thereon, and a duplexer that returns said photographic print media to said print engine for printing on a second side of said photographic print media.

Printing mechanism

In an inkjet printing apparatus an inkjet printhead ejects ink into a print-zone. A drive shaft, located upstream of the printhead, has a longitudinal axis, a first radius over a central length, and a second radius less than the first radius at a first recess and a second recess. Each recess is peripheral to the central length. A plurality of pinch devices stabilize the media against the drive shaft. A first guide and a second guide, spaced from the longitudinal axis, are aligned with and extend into the first recess and second recess.

Apparatus for advancing media through a hardcopy device includes a cylindrical guide wheel having a first radius mounted on a shaft having an axis transverse to a media feed path axis. A guide surface is spaced apart from the guide wheel and defines a media feed path between the guide wheel and the guide surface. A drive wheel having an extended portion that is concentric with the guide wheel, and which has a greater radius than the first radius is fixed to the shaft. A pinch roller communicates with the media feed path.

Input converger for hardcopy devices

The invented printer includes a paper drive and mechanisms which hold paper in proper alignment in the drive. Specifically, it includes a pressure plate capable of bringing a sheet of paper into contact with a drive roller so that the paper is properly aligned, a wrapper which keeps paper in proper contact with the drive roller, a media edge contactor that presses against paper, a carriage guide support which helps to insure proper alignment of the paper during printing, and a back-out restraint to prevent paper from backing out of the printer.

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Brush Prairie, WA, United States of America

Vance M Stephens