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Ink jet printer

  • US 4,412,232 A
  • Filed: 04/15/1982
  • Issued: 10/25/1983
  • Est. Priority Date: 04/15/1982
  • Status: Expired due to Fees
First Claim
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1. A hand-held ink jet printer, comprising:

  • a housing;

    at least one wheel rotatably mounted on said housing to support said housing for manual movement over a medium onto which characters are to be printed by the printer;

    a movement sensing device for sensing the rotation of said wheel;

    a print head within said housing and having a plurality of nozzles and a piezoelectric element associated with each of said nozzles for being selectively energizable to cause ejection of a droplet of ink from its associated nozzle, said piezoelectric element driven in response to the movement of said housing;

    a container having an ink reservoir and connected for supplying ink to be ejected through said nozzles, the ink in said ink reservoir maintained at a predetermined underpressure relative to atmospheric pressure outside said container so that the ejection of ink can be controlled by the energization of each said piezoelectric element; and

    a collapsible bellows device connected by a tube to said ink reservoir, said bellows device having resilient side walls so that, as ink is ejected through said nozzles, said bellows device collapses to reduce the interior volume of said container, with said resilient side walls biased against the collapsing of said bellows device in order to maintain the predetermined underpressure of the ink in said ink reservoir.

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