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Compensation for Uniform Drop Deflection

IP.com Disclosure Number: IPCOM000082258D
Original Publication Date: 1974-Nov-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 2 page(s) / 42K

Publishing Venue

IBM

Related People

Zable, JL: AUTHOR

Abstract

In a magnetic ink jet printer, a stream of magnetic ink drops 10 from a drop generator 11 is directed along a path successively between poles 12 of an electromagnetic selector 13 and poles 15 of deflector electromagnets 16 to a print medium 18. Drop selection pulses are applied to winding 14 of selector 13 to horizontally displace certain drops 10 from the stream trajectory, to ultimately be intercepted by a drop catcher 19 located in advance of the print medium 18.

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Compensation for Uniform Drop Deflection

In a magnetic ink jet printer, a stream of magnetic ink drops 10 from a drop generator 11 is directed along a path successively between poles 12 of an electromagnetic selector 13 and poles 15 of deflector electromagnets 16 to a print medium 18. Drop selection pulses are applied to winding 14 of selector 13 to horizontally displace certain drops 10 from the stream trajectory, to ultimately be intercepted by a drop catcher 19 located in advance of the print medium 18.

As the drops 10 pass between poles 15 of deilector electromagnet 16, they are subjected to a vertical deflection force generated by a deflection signal applied from source 20 to winding 17. The vertical deflection for a deflection field of substantial horizontal length resulting from a constant amplitude pulse, results in nonlinear deflection of successive drops. Thus the droplets will arrive at the print medium 18 at successively different times, resulting in slightly distorted characters.

Fig. 2 shows a modified square-wave signal applicable to the winding 17 of deflector 16 which compensates for the nonlinear displacement of drops, so that they are substantially uniformly spaced as deflected during the time of energization of the winding 17.

In the circuit of Fig. 3 for producing a waveform of Fig. 2, the deflector winding 17 is connected in series with resistor 21 and capacitor 22 and switch
23. When switch 23 is in position A, the current from voltage sour...