Recorders – Record receiver deforming
Patent
1981-05-29
1983-02-22
Miller, Jr., George H.
Recorders
Record receiver deforming
346140R, G01D 1518
Patent
active
043750621
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to continuous stream ink jet printers, and more particularly relates to an aspirator configuration for such printers.
STATE OF THE PRIOR ART
During the continuous ink jet printing process, charged ink droplets enter a strong electric field which accelerates them more or less proportionally to their charge. As the drops separate from interaction with the field, they follow a multiplicity of trajectories, staggered in time and position. At any instant, the drops respond to the vector sum of electric field and aerodynamic forces, as well as self weight due to gravity which is usually neglected because the mass of the individual droplets is small. As the drops change their relative positions, the vector sum of forces also changes with the effect of perturbing the drop trajectories. Empirical correction techniques which compensate for this drop interaction are complex if they are applicable to all possible drop patterns. For example, the IBM 6640 continuous stream ink jet printer employs a complex guard drop scheme such as illustrated in U.S. Pat. No. 4,086,601, issued on Apr. 25, 1978.
It is the purpose of aspiration to reduce the magnitude of inter-drop forces and simplify the drop placement logic which must adjust the individual drop charge to compensate for these perturbations.
In essence, aspiration attempts to directly minimize aerodynamic perturbations between the drops by surrounding them with a column of co-linearly moving air, the effect of which is to reduce the relative velocity of the drop with respect to its surroundings to a minimum. This results in reduced particle drag while minimizing the intensity of the momentum wake trailing the drop. As a consequence, the drops may traverse longer trajectories. By allowing the traversal of the drops in longer trajectories, electric field deflection efficiency is greatly enhanced and electrostatic inter-drop interaction is reduced because the actual charge applied to each drop by the charge electrode may be reduced.
In U.S. Pat. No. 3,596,275 to Richard B. Sweet, Jr. July 27, 1971, column 5, line 65 et seq there is a discussion of both co-linear or perpendicular aspiration. U.S. Pat. No. 3,972,051, Lundquist, et al., issued July 27, 1976, discloses a small air duct surrounding the ink stream so that the air is slowed as it approaches the paper. The relative velocity between the drops and the air is reduced, but minimization of air to ink drop velocity is not achieved and is in fact avoided in the exit of the air tunnel. In the Hendriks and Giordano, U.S. Pat. No. 4,097,872, issued on June 27, 1978, a structure is taught for reducing the overall stream turbulance and elimination of the wake associated with the drop source (such as illustrated in the aforementioned Sweet reference), with the intent of approaching the ideal zero relative velocity of the drop and air throughout the trajectory of the drop. The Giordano et al. patent introduced novel innovations to the flow pattern to achieve an almost zero relative velocity between the ink and air. First flow straightners are employed upstream from a hemispherical settling chamber wherein the fine scale turbulance generated by the air passing through porous screens would have time to dissipate before entering the tunnel duct. Next, the co-linear air stream was folded back on itself, effectively placing the source of charged drops outside the main air flow. This eliminated the generation of wake from the drop generator as practiced in Sweet's configuration. Finally, the cross-sectional area of the tunnel was constrained to substantially a constant. It has been discovered that maintaining the cross-sectional area of the tunnel (or duct) to a constant does not achieve an optimal configuration for a minimum relative velocity between the ink and the air.
SUMMARY OF THE INVENTION
In view of the above, it is a principle object of the present invention to provide an aspirator for a continuous stream ink jet printer wherein the relative velocity between the ink and the
REFERENCES:
patent: 4097872 (1978-06-01), Giordano et al.
patent: 4297712 (1981-10-01), Lammers et al.
Dick William J.
International Business Machines - Corporation
Miller Jr. George H.
LandOfFree
Aspirator for an ink jet printer does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Aspirator for an ink jet printer, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Aspirator for an ink jet printer will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1375201