Xerox Corporation

Delphax Systems

Wm Keith Baker

Sotos M Theodoulou

Christopher W Thomson

Eric F Vannerson

Eric Vannerson

Ken Hurley

Alvin C Sun

The present invention provides a method and a circuit for driving control electrodes between a reset voltage and an adjustable extraction voltage. The circuit includes a reset switch having first and second terminals with the first terminal being connected to a high voltage source. A plurality of set switches, each capable of assuming an on state and an off state connected such that a first terminal of each set switch is connected to a corresponding one of the control electrodes and a second terminal is connected to a low voltage source. The circuit further includes a plurality of diodes, each being connected between the second terminal of the reset switch and a corresponding one of the control electrodes. A plurality of current sources, each current source being capable of assuming an enabled and a non-enabled state, are connected between a high voltage source and a corresponding one of the control electrodes to supply a constant current to the control electrodes and thereby adjust the extraction voltage at the control electrode.

Adjustable voltage finger driver

The present invention provides a method and circuit for driving control electrodes between a reset voltage and an adjustable control voltage. The circuit includes a reset switch capable of assuming a first state and a second state, the reset switch including a first terminal connected to a first voltage source; a plurality of diodes, each one of the plurality connected between a second terminal of the reset switch and a corresponding one of the control electrodes; and a plurality of voltage control switches, each voltage control switch being capable of assuming an active state and an inactive state, each voltage control switch including a first terminal connected to a corresponding one of the control electrodes and a second terminal connected to a second voltage source, wherein the extraction voltage supplied to a control electrode is adjusted by adjusting the length of time that the corresponding voltage source is made active.

A device for providing an RF signal burst to an external load includes a voltage-controlled oscillator to generate a drive signal having a frequency f.sub.VCO fixed by an oscillator control signal. An RF driver stage coupled to the external load receives the drive signal and generates an RF signal burst in response to the drive signal. A current transformer coupled between the RF driver stage and the external load senses the current in the RF driver stage and generates a reference current having the same phase as the sensed current. A phase detector receives the reference current along with the drive signal and generates a phase detection signal that provides a measure of the phase of the current in the RF driver stage with respect to the drive signal. The phase detection signal can be used to adjust the oscillator control signal to drive the oscillator frequency to a desired value.

High frequency RF driver

Ionographic raster scan printing apparatus capable of printing with selectable print density utilizes an imaging drum having a surface movable in a process direction, a connector assembly for receiving an imaging module having a characteristic dot density determined by a set of control electrodes individually driven by clocked driver elements, a sensor module for generating density signals representative of the characteristic dot density, and a position encoder for generating position signals representative of the instantaneous position of the imaging drum surface. A scan clock synthesizer module generates activation signals for clocking the driver elements, the signals having a clock frequency proportional to an algebraic combination of the density signals and the position signals.

Growing community of inventors

Belfountain, Canada

Wm Keith Baker