EP0624469B1 - Générateur amélioré de gouttellettes avec amortissement pour la suppression de vibration - Google Patents

Générateur amélioré de gouttellettes avec amortissement pour la suppression de vibration Download PDF

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Publication number
EP0624469B1
EP0624469B1 EP19940303109 EP94303109A EP0624469B1 EP 0624469 B1 EP0624469 B1 EP 0624469B1 EP 19940303109 EP19940303109 EP 19940303109 EP 94303109 A EP94303109 A EP 94303109A EP 0624469 B1 EP0624469 B1 EP 0624469B1
Authority
EP
European Patent Office
Prior art keywords
damping
resonator
mode
print head
head device
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP19940303109
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German (de)
English (en)
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EP0624469A1 (fr
Inventor
James A. Katerberg
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Kodak Versamark Inc
Original Assignee
Kodak Versamark Inc
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Filing date
Publication date
Application filed by Kodak Versamark Inc filed Critical Kodak Versamark Inc
Publication of EP0624469A1 publication Critical patent/EP0624469A1/fr
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Anticipated expiration legal-status Critical
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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
    • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
    • B41J2/01—Ink jet
    • B41J2/135—Nozzles
    • B41J2/145—Arrangement thereof
    • B41J2/155—Arrangement thereof for line printing
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
    • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
    • B41J2/01—Ink jet
    • B41J2/015—Ink jet characterised by the jet generation process
    • B41J2/02—Ink jet characterised by the jet generation process generating a continuous ink jet
    • B41J2/025—Ink jet characterised by the jet generation process generating a continuous ink jet by vibration

Definitions

  • the present invention relates to ink jet drop generators and, more particularly, to an improved structure for an ink jet drop generator.
  • ink is supplied under pressure to a manifold region that distributes the ink to a plurality of orifices, typically arranged in a linear array(s).
  • the ink discharges from the orifices in filaments which break into droplet streams.
  • the approach for printing with these droplet streams is to selectively charge and deflect certain drops from their normal trajectories.
  • U.S. Patent No. 4,999,647 discloses a drop generator for use with a long array of holes such that the length is larger than the height. A plurality of slots were employed to insure uniform vibration amplitude of the longitudinal mode (height direction) across the orifice plate face.
  • a n B n /[(f n 2 - f 2 ) + c]
  • a n is the vibration amplitude of mode n
  • B n is a constant depending on the mode shape
  • f n is the resonant frequency of node n
  • f is the driving frequency
  • c is a small value related to attenuation.
  • the amplitude of A n+1 would be B n+1 /((f n+1 2 - f n 2 ) + c) .
  • the separation between the resonant modes, f n+1 - f n decreases.
  • the ratio of their amplitudes A n /A n+1 decreases. It is therefore harder to excite the mode n without also exciting the n+1 mode.
  • the undesirable excitation of an adjacent resonant mode can produce unacceptable stimulation uniformity across the array.
  • the degree to which the undesirable modes are excited and subsequently the level of vibration uniformity across the array may be unacceptably sensitive to the operating frequency and manufacturing tolerances.
  • EP-A-0126649 discloses a fluid jet print head having a transducer arrangement, including piezoelectric means and having acoustic isolation material surrounding the piexoelectric means.
  • the transducer means when excited, produces pressure waves of uniform wave front which travel through fluid in a reservoirtowards an orifice plate.
  • US-A-4135197 discloses an ink jet printing device having a vibration damping means in the printing head, which comprises comprises an adjustably positionable rigid contact member that engages the surface of the orifice plate at a position remote from the vibration stimulation means that produces a high frequency standing wave vibration longitudinally in the orifice plate.
  • One important object of the present invention is to provide an improved structure for an ink jet drop generator which can utilize long arrays of ink jets. This is accomplished by an approach wherein the system is designed to include damping means for suppression of undesired vibration modes.
  • the present invention provides a print head device for use in continuous ink jet printing, the device comprising a resonator means having an ink supply body formed of a solid high acoustic Q material; transducer means attached to the resonator means; and means for energizing the transducer means in a resonant mode at a desired drop frequency to induce vibration in the resonator means; and damping means which suppress undesired interfering vibration modes of the resonator means, to achieve uniformity of the vibration mode of the resonator means, the damping material comprising a viscoelastic material placed on or around locations of the printhead having relatively high stress in the interfering modes and relatively low stress in the desired mode.
  • Fig. 1 schematically illustrates the components that cooperate to comprise a prior art embodiment of a drop ejection device.
  • drop ejection device generally referred to as 10
  • the device 10 functions to produce the desired streams of uniformly sized and spaced drops in a highly synchronous condition.
  • Other continuous ink jet printer components such as charge and deflection electrodes, drop catcher, media feed system and data input and machine control electronics (not shown) cooperate with the drop streams, produced by device 10 to effect continuous ink jet printing.
  • the drop generator 10 is constructed to provide synchronous drop streams in a long array printer, and comprises a resonator/manifold body 12.
  • the resonator/manifold body 12 is constructed of a high acoustic Q material, e.g. stainless steel, and in the form of a predeterminedly dimensioned rectangular solid, the length (l) of which is substantially greater than its height (h) , which body height (h) is substantially greater than the body thickness.
  • an orifice plate 14 having a plurality of orifices is bonded onto the resonator body 12.
  • the resonator body 12 also includes an ink supply body or fluid cavity 16, having fluid cavity side walls for containing the ink. It is understood that the resonator/manifold body 12 further includes fluid ports, or fluid fittings 20, for supplying ink from a fluid supply means to the ink supply cavity.
  • the fluid inlet and outlet fittings 20 may comprise thin wall tubing bent to form an elbow 24, over which flexible ink conduit lines 22 may be attached.
  • Pins 26, protruding outward from the front and back faces of the resonator body 12 can be used to mount the drop generator 10 in a support frame, such as frame 34 in Fig. 6.
  • a plurality of piezoelectric elements 18 are used to induce the vibration of the resonator/manifold body 12.
  • the desired vibration mode for good stimulation is typically the longitudinal mode in the h direction.
  • the resonator/manifold body 12 expands and contracts in the h direction.
  • the slots 28 ensure that the uniformity of this longitudinal mode is sufficient for proper drop generation operation.
  • damping means may be utilized.
  • a typical damping means comprises a damping material such as viscoelastic materials. As these materials undergo periodic stress or strain, they convert some of the vibrational energy into heat, attenuating the vibration amplitude. Since these materials must undergo periodic stress to attenuate the vibration amplitude, they are most effective when they are attached to the high stress regions of the resonating system. Suppression of the undesirable vibration mode therefore involves attaching damping materials to those areas of drop generator 10 where the stresses are concentrated for such undesired modes. Conversely, the damping materials should not be attached to those areas of the drop generator 10 having high stress in the longitudinal mode.
  • Fig. 2 illustrates one possible vibration mode of the fittings. In this mode, the elbow 24 can be seen to flex in and out.
  • the resonant mode of Fig. 2 can couple into the resonator body 12 affecting the vibration uniformity at the orifice plate 14, or it can drive a pressure wave in the fluid cavity 16.
  • the placement of a damping rubber sleeve 30 around the elbow 24 as shown in Fig. 3 can strongly attenuate this mode while having little effect on the resonator body longitudinal mode.
  • a second type of interfering vibrational mode involves flexure modes of the sides of the cavity.
  • the side walls 32 around the fluid cavity can undergo flexure modes in the form of standing waves down the array.
  • Fig. 4 is representative of only one of many possible cavity wall flexure modes. Such modes can produce large variations in the stimulation amplitude down the array.
  • cavity flexure modes can be suppressed by attaching damping material 36, such as E-A-R/SC SD-40PSA material to the side walls 32 of the fluid cavity 16 as shown in Fig. 5. As the stresses are low near the end of the resonator in the longitudinal mode, the longitudinal mode is not strongly attenuated by the damping material.
  • the third type of interfering resonance involves the drop generator mounting frame.
  • the drop generator is mounted in a frame 34 by means of pins 26.
  • the pins 26 are located near the nodal plane of the drop generator 10, they are able to couple some vibrational energy from the drop generator 10 to the frame 34. If the frame has a resonance near the operating frequency of the drop generator this can result in the frame 34 resonating. The vibration of the frame 34 can then be coupled back into the drop generator 10 through the pins 26, affecting the stimulation uniformity.
  • applying damping material 38 to the frame can suppress the frame resonance so that the stimulation uniformity is not degraded, without adversely affecting the longitudinal mode of the resonator.
  • damping rubber sleeve 30, the damping material 36 and the damping material 38 being used for mode suppression may be used singularly or cooperatively, depending on the presence or absence of the interfering modes for a particular drop generator.
  • interfering resonant modes illustrated herein are examples of some of the many interfering resonant modes which may be present in drop generator designs, and are not to be considered as limiting the scope of the invention.
  • the desired suppression of the interfering mode can be produced by placement of the damping material in regions having relatively high stress in the interfering modes and relatively low stress in the desired mode.
  • the present invention is useful in the field of ink jet printing, and has the advantage of suppressing undesired vibration and interfering resonant modes.
  • the present invention has the further advantage of providing such suppression without adversely affecting the longitudinal mode of the resonator.

Landscapes

  • Particle Formation And Scattering Control In Inkjet Printers (AREA)

Claims (6)

  1. Dispositif pour tête d'impression destiné à servir dans l'impression à jet d'encre continu, le dispositif comprenant :
    a. des moyens formant un résonateur ayant un corps d'alimentation en encre (12) formé en un matériau solide de haute qualité acoustique ;
    b. des moyens formant un transducteur (18) fixés aux moyens formant un résonateur ;
    c. des moyens pour activer les moyens formant un transducteur dans un mode d'onde résonant à une fréquence de gouttes souhaitée pour provoquer des vibrations dans les moyens formant un résonateur ; et
    d. des moyens d'amortissement (36) qui suppriment des modes vibratoires parasites non souhaités des moyens formant un résonateur, pour obtenir l'uniformité du mode vibratoire des moyens formant un résonateur, les moyens d'amortissement comprenant une matière viscoélastique placée sur ou autour d'emplacements de la tête d'impression ayant une contrainte relativement élevée dans les modes parasites et une contrainte relativement faible dans le mode souhaité.
  2. Dispositif pour tête d'impression selon la revendication 1, dans lequel les moyens formant un résonateur ont des ports de fluide pour acheminer l'encre depuis des moyens d'alimentation en fluide jusqu'au corps d'alimentation en encre et les moyens d'amortissement (36) appliquent un amortissement aux ports de fluide pour supprimer un mode vibratoire parasite non souhaité.
  3. Dispositif pour tête d'impression selon la revendication 2, dans lequel les moyens d'amortissement comprennent un manchon en caoutchouc placé autour d'une partie d'un port de fluide subissant une importante concentration de contraintes dans un mode vibratoire particulier non souhaité.
  4. Dispositif pour tête d'impression selon la revendication 1, dans lequel le corps d'alimentation en encre comprend des parois latérales de cavité de fluide (32) destinées à contenir l'encre et les moyens d'amortissement (36) appliquent un amortissement aux parois latérales de cavité de fluide (32) pour supprimer des modes vibratoires parasites non souhaités.
  5. Dispositif pour tête d'impression selon la revendication 1, dans lequel les moyens formant un résonateur sont montés dans un châssis de support (34) et les moyens d'amortissement (38) appliquent un amortissement au châssis de support (34) pour supprimer un mode vibratoire parasite non souhaité.
  6. Dispositif pour tête d'impression selon la revendication 5, dans lequel les moyens formant un résonateur sont montés dans un châssis de support (34) A l'aide d'une pluralité d'ergots (26).
EP19940303109 1993-05-12 1994-04-28 Générateur amélioré de gouttellettes avec amortissement pour la suppression de vibration Expired - Lifetime EP0624469B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US6139193A 1993-05-12 1993-05-12
US61391 1993-05-12

Publications (2)

Publication Number Publication Date
EP0624469A1 EP0624469A1 (fr) 1994-11-17
EP0624469B1 true EP0624469B1 (fr) 1998-06-10

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP19940303109 Expired - Lifetime EP0624469B1 (fr) 1993-05-12 1994-04-28 Générateur amélioré de gouttellettes avec amortissement pour la suppression de vibration

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EP (1) EP0624469B1 (fr)
DE (1) DE69410878T2 (fr)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0805026B1 (fr) * 1996-04-30 2000-05-24 SCITEX DIGITAL PRINTING, Inc. Procédé de brasage fort pour une tête d'impression à jet d'encre continu
EP0805036B1 (fr) * 1996-04-30 2001-09-19 SCITEX DIGITAL PRINTING, Inc. Générateur de gouttelettes à alimentaion par le haut
GB9709462D0 (en) * 1997-05-09 1997-07-02 Videojet Systems Int A droplet generator for a continuous stream ink jet print head

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4135197A (en) * 1977-10-14 1979-01-16 The Mead Corporation Vibration damping means for ink jet printing device
DE3006726C2 (de) * 1980-02-22 1982-03-11 Siemens AG, 1000 Berlin und 8000 München Tintenschreibeinrichtung
DE3470398D1 (en) * 1983-05-19 1988-05-19 Mead Corp Fluid jet print head
IT1178828B (it) * 1984-01-20 1987-09-16 Olivetti & Co Spa Dispositivo di stampa a getto selettivo di inchiostro
US4999647A (en) * 1989-12-28 1991-03-12 Eastman Kodak Company Synchronous stimulation for long array continuous ink jet printer

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Publication number Publication date
DE69410878D1 (de) 1998-07-16
EP0624469A1 (fr) 1994-11-17
DE69410878T2 (de) 1998-10-08

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