(19)
(11) EP 0 716 926 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
16.04.1997 Bulletin 1997/16

(43) Date of publication A2:
19.06.1996 Bulletin 1996/25

(21) Application number: 95309100.6

(22) Date of filing: 14.12.1995
(51) International Patent Classification (IPC)6: B41J 2/16, B41J 2/045
(84) Designated Contracting States:
DE FR GB IT SE

(30) Priority: 16.12.1994 US 357725

(71) Applicant: Compaq Computer Corporation
Houston, Texas 77070-2698 (US)

(72) Inventors:
  • Good, Lowell M.
    Cypress, Texas 77379 (US)
  • Wallace, David B.
    Dallas, Texas 75205 (US)

(74) Representative: Brunner, Michael John et al
GILL JENNINGS & EVERY Broadgate House 7 Eldon Street
London EC2M 7LH
London EC2M 7LH (GB)

   


(54) Length-mode drop-on-demand ink jet printhead for ejecting orthogonally directed droplets at improved operating speeds


(57) A length-mode ink jet printhead which includes an active lower body portion, a series of active intermediate body portions and an inactive upper body portion which collectively define a series of generally parallel channels which extend between front and rear side surfaces of the printhead. Each channel is bounded by first and second sidewalls, each comprised of a lower body projection and an intermediate body portion conductively mounted thereto. Formed in the upper body portion are a series of ink ejection orifices, each of which extends from the top side surface to a corresponding one of the series of channels and is located midway between the front and rear side surfaces of the printhead. Mounted on the front and rear side surfaces of the printhead are acoustic pressure wave reflection interfaces for respectively reflecting forwardly and rearwardly propagating pressure waves generated in the series of channels. An orthogonally directed droplet of ink is ejected from an ink ejection orifice by imparting an acoustic pressure wave to a selected channel in communication with the ink ejection orifice.






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