Browse Prior Art Database

Fluid Droplet Printer

IP.com Disclosure Number: IPCOM000079463D
Original Publication Date: 1973-Jul-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 2 page(s) / 41K

Publishing Venue

IBM

Related People

Lee, C: AUTHOR [+2]

Abstract

Input data from an external source is converted to an analog voltage by D-to-A converter 25 and amplified by amplifier 26, where it is applied to charge pin 33 located in the stream of droplets 32 generated from source 23. A data clock 41 applies timing pulses to the D-to-A converter 25 for proper gating of the voltage on pin 33.

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Fluid Droplet Printer

Input data from an external source is converted to an analog voltage by D-to- A converter 25 and amplified by amplifier 26, where it is applied to charge pin 33 located in the stream of droplets 32 generated from source 23. A data clock 41 applies timing pulses to the D-to-A converter 25 for proper gating of the voltage on pin 33.

When an ink droplet 32 strikes pin 33 and a voltage is present on that pin from amplifier 26 a small current passes from the voltage amplifier 26 through charge pin 33, droplet 32, charge plate 34, and current sensor 35 to ground. Sense amplifier 42 connected to current sensor 35 detects the presence of this current and converts it to a logic level. Phase detector 43 connected to sense amplifier 42 determines the timing relationship between this output pulse and the data clock 41, and gives an output pulse whose duty cycle is proportional to that relationship.

Voltage control single-shot 45 fires once each data clock cycle so that its frequency is the same as the data clock 41. The output of the phase detector 43 is filtered through integrator 44, where it controls the duration of single-shot 45. Integrator 46 on the output of single-shot 45 then filters the output and presents the resulting analog voltage to the voltage-controlled, variable-frequency, sine- wave oscillator 47. Integrators 44 and 46 would be designed to have a desired frequency response phase and amplification, particularly integrator 46, where the closed-loop responses match the mechanical delay time inherent between crystal transducer 29 of source 23 and the time a perturbed droplet arrives and is detected at charging plate 34,...