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US 4,588,997 AGranted
Electrographic writing head
AssigneeXerox Corporation
InventorsHsing C. Tuan, Malcolm J. Thompson
Life of this patent
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Abstract
An electrographic writing head capable of placing continuous marks upon a record medium in response to the application of a high voltage to selected writing styluses. The writing head includes a substrate upon which stylus electrodes, multiplexed driver circuitry and active devices are integrally fabricated by thin film deposition techniques. For each stylus, there is provided a high voltage thin film transistor and a latching circuit for holding the state of the high voltage transistor for substantially an entire line writing time.
Claims13
An improved thin film electrographic marking head characterized by comprising
- a substrate,
- a plurality of marking electrodes upon said substrate,
- a plurality of high voltage transistors upon said substrate, each high voltage transistor connected to a marking electrode, each high voltage transistor including a source electrode, a drain electrode and a gate electrode, and each of said high voltage transistors being capable of switching a marking potential of several hundred volts between said source and said drain by means of a gate potential of at least an order of magnitude lower than said source to drain potential,
- a plurality of latching means each connected to said high voltage transistor gate electrodes,
- data input means for selectively loading a gate potential on said gate electrodes through said latching means, in a fraction of a line time, said latching means holding said gate potential on said high voltage transistors for substantially an entire line time, and
- said marking electrodes, said high voltage transistors, said latching means and said data input means being thin film elements integrally formed upon said substrate.
3 more elements
Dependencies are inferred from the claim text.