Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
1997-03-25
2001-10-02
Barlow, John (Department: 2853)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
Reexamination Certificate
active
06296350
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to ink jet printers having a driver circuit for applying warming and firing pulses to ink jet printer heating elements.
BACKGROUND OF THE INVENTION
Drop-on-demand ink jet printers use thermal energy to produce a vapor bubble in an ink filled chamber to expel a droplet. A thermal energy generator or heating element, usually a resistor, is located in the chamber near a discharge orifice. A plurality of chambers, each provided with a single heating element, are provided in the printer's printhead. The resistors are individually addressed with an energy pulse to momentarily vaporize the ink and form a bubble which expels an ink droplet. Preferably, each ink droplet travels along a substantially straight-line path as it moves from the orifice to the recording medium, such as paper. The straight-line path is generally perpendicular to the printhead. At times, a small amount of ink collects on the outer surface of the printhead around one or more of the orifices. As the droplets travel out of the orifices, they may be contacted by this excess ink causing them to be diverted from their intended straight-line paths of movement.
It would be desirable to provide an ink jet printer which generates droplets that travel along substantially straight-line paths even if ink collects around the printhead orifices and contacts the ejected droplets.
SUMMARY OF THE INVENTION
The instant invention is directed to an ink jet printing apparatus which applies to each heating element a warming pulse and a firing pulse separated from one another by a delay period. A first quantity of thermal energy is applied to a thin layer of ink located just above the surface of the heating element as a result of the warming pulse. This energy is allowed to diffuse or “soak” into the ink during the delay period. A second quantity of thermal energy is transferred to the ink just above the heating element when a firing pulse is applied to the heating element at the end of the delay period. Assuming that the delay period is not too long or too short, the first and second quantities of thermal energy result in the formation of an ejection bubble having increased momentum. Such a bubble causes the resulting ejected ink droplet to likewise have increased momentum. The increased momentum, however, is due to a significant extent to an increase in velocity rather than droplet mass. The droplets ejected by the printing apparatus of the present invention, because of their increased velocity, are less likely to be diverted from their intended straight-line paths by ink which has collected on the outer surface of the printhead.
REFERENCES:
patent: 4313124 (1982-01-01), Hara
patent: 4490728 (1984-12-01), Vaught et al.
patent: 4503444 (1985-03-01), Tacklind
patent: 4638337 (1987-01-01), Torpey et al.
patent: 4746937 (1988-05-01), Realis Luc et al.
patent: 4982199 (1991-01-01), Dunn
patent: 5036337 (1991-07-01), Rezanka
patent: 5063655 (1991-11-01), Lamey et al.
patent: 5107276 (1992-04-01), Kneezel et al.
patent: 5138333 (1992-08-01), Bartky et al.
patent: 5172134 (1992-12-01), Kishida et al.
patent: 5285215 (1994-02-01), Liker
patent: 5300969 (1994-04-01), Miura et al.
patent: 5420618 (1995-05-01), Sekiya et al.
patent: 5559535 (1996-09-01), Otsuka et al.
patent: 5657060 (1997-08-01), Sekiya et al.
patent: 5838340 (1998-11-01), Shimoda
patent: 5963233 (1999-10-01), Shirota et al.
patent: 0 626 261 (1994-11-01), None
patent: 0 694 395 (1996-01-01), None
patent: 0 816 084 (1998-11-01), None
patent: WO90 10541 (1990-09-01), None
Cornell, R., “A Theoretical and Experimental Examination of Thermal Ink Jet Nucleation Criteria,” IS&T'NIP12: International Conference on Digital Printing Technologies, Oct./Nov. 1996, pp. 19-24.
Cornell Robert Wilson
Gibson Bruce David
Barlow John
Brady John A.
Brooke Michael S
Lexmark International Inc.
LandOfFree
Ink jet printer having driver circuit for generating warming... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Ink jet printer having driver circuit for generating warming..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Ink jet printer having driver circuit for generating warming... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2585936