Tektronix, Inc.

Xerox Corporation

Other

Bruce K Baur

David Lyell Knierim

Christian Carl Gadke

Nathaniel Morrison

Aaron L Boyce

Lee M Oien

Roger Gaylord Leighton

Ernest I Esplin

Joseph Benjamin Gault

John Charles Dalrymple

Michael Cameron Gordon

Scott J Phillips

Abu Saeed Islam

Alexander J Fioravanti

Larry Eugene Hindman

Kelly Anne Kessler

Gordon W Meigs

John R Ollis

Cory A Westerlund

Christian C Gadke

A method responds to an over-temperature condition in a printhead. The method includes generating a first electrical signal corresponding to a temperature in a printhead, monitoring the first electrical signal with a first electronic circuit to terminate delivery of electrical power to a printhead in response to detection of a safety event, and monitoring the first electrical signal with a second electronic circuit to regulate an amount of electrical power delivered to the printhead.

System and method for protecting a printer from an over-temperature condition in a printhead

A maintenance system and method for maintaining an imaging member of an imaging device includes a pre-cleaning device to clean the imaging member; an applicator to apply release agent to the imaging member; a metering device to meter release agent on the imaging member; a reservoir to remotely store release agent; and a pump to supply the applicator with release agent from the reservoir. The saturation level of the applicator is monitored and maintained within a predetermined range. The applicator, pre-cleaning device and metering device may be independently actuated to engage the imaging member. Release agent collected by the pre-cleaning device and/or metering device may be recycled. Debris collected by the pre-cleaning device and/or metering device may be stored and/or removed.

Drum maintenance system for an imaging device and method and system for maintaining an imaging device

A duty cycle based AC power control method reduces objectionable voltage fluctuations at a frequency that causes 'flicker' by shifting the frequency of actuations of controlled devices to frequencies significantly greater than and/or less than the flicker sensitive frequency. The frequency of actuations may be redistributed (1) by segmenting the devices to provide approximately equal power requirements per actuation, (2) by providing one-half cycle actuation pulses rather than one cycle actuation pulses, and/or (3) by spacing the actuations evenly over a given time period and forcing the aggregate demand to follow a slowly rising/falling envelope. The result is the minimization of power distribution at the flicker frequency.

Duty cycle based AC power control with reduced voltage fluctuations

A base drive compensation circuit for a power amplifier samples a fixed saturation voltage level on the output of a power transistor and couples the sampled output to an inverting input of an error amplifier having a sawtooth signal on its non-inverting input. The output of the error amplifier is a negative going signal whose duty cycle is established by the voltage level on the inverting input. The negative going signal is coupled to a switching power supply that develops a voltage which controls the base drive current to the power transistor.

Compensation circuit for power amplifier

A base drive circuit for a flyback output transistor has an inductive element having series connected coils for generating a linear ramping current to the base electrode of the output transistor in response to an input pulse. A high, almost instantaneous reverse current is produced through a discharge coil that receives inductively coupled energy from the current generating coils. The ratio of the maximum input current to the discharge current is established by the number of coils generating the input current versus the number of coils in the discharge circuit. Linearity of the base drive current is maintained by dissipating any excess energy in the inductive element to ground prior to each input pulse.

High speed base drive for power amplifier

A silicon controlled rectifier (SCR) is connected between a selected electrode of a CRT and a reference potential level that is negative relative to the selected CRT electrode. The SCR remains non-conductive so long as the voltage between the selected electrode and the reference potential level remains below the breakdown voltage of the SCR and the SCR's dv/dt rating is not exceeded. If the voltage between the electrode and the reference potential level increases at a rate that exceeds the threshold rate for the SCR, the SCR turns on and shorts the selected electrode to the reference potential level.

Circuit arrangement for protecting a CRT and associated circuitry from

A power amplifier circuit for driving an inductive load comprises a capacitor coupled between first and second circuit nodes, a first unidirectionally-conductive device having a first terminal coupled to the first circuit node, and a transistor having its collector coupled to the second terminal of the first unidirectionally-conductive device and having its emitter coupled to the second circuit node. The direction of conduction of the first unidirectionally-conductive device is the same as the direction of conduction through the collector-emitter path of the transistor. The circuit also comprises a second unidirectionally-conductive device connected in parallel with the first unidirectionally-conductive device for conducting current in the opposite direction from the direction of conduction of the first unidirectionally-conductive device.

Power amplifiers for driving inductive loads

A circuit including a conventional digital-to-analog converter (DAC) and a charge pump for producing an analog representation of an input waveform defined by an input digital bit stream, the analog representation being relatively free of spurious aberrations usually present in the output of a conventional DAC. The charge pump and an associated integrator are used to produce a first approximation of the input waveform and the DAC and an associated detuned slew-rate filter are used to maintain the first approximation in long-term conformance with a more accurate second approximation. Spurious aberrations in the second approximation are integrated over several steps of the input bit stream, thereby minimizing their adverse impact on the relatively true first approximation.

Growing community of inventors

Milwaukie, OR, United States of America

Bruce K Baur