Hewlett-packard Company

James A Kazakoff

Jeffrey L Trask

Brian E Hoffmann

Richard H Benear

David S Pitou

Rulon G Esplin

Fine pulse width modulation (PWM) adjustments in the output of a laser printer are accomplished by receiving values from a bit map and modifying the values in accordance with values in a lookup table (LUT). The lookup table is subdivided into a plurality of blocks, and a selection of the blocks is made in accordance with external values. This allows the output of a pulse width modulation circuit to be adjusted to a precision that is greater than that afforded by the bit size of the values from the bit map. The use of plural blocks in the lookup table permits adjustments in the output of the pulse width modulation circuit in accordance with external factors such as relative humidity, sensitivity of an optical photoreceptor, and developer life.

Adjustment of dot size for laser imagers

In hard copy machines, automatic detection of the size of print media in a supply bin is provided by electrical devices. Adjustable print media alignment fences are operatively connected to the electrical devices, such as potentiometers, photovoltaic strips, photoemitter-photodetector arrays, or the like. The output signals from the electrical devices are correlated to width and length dimensions of the print media or the absence of print media availability. Embodiments are disclosed for standard and custom print media size detection.

Print media supply apparatus with media parameter detection capability

Embodiments are shown and described of an electrode biasing scheme and developer design for use with liquid electrophotographic imaging machines. The biasing scheme includes a bi-modal charge transport characteristic, wherein the time constant for reverse-plating is prolonged compared to the time constant for forward-plating. This characteristic may be achieved with a diode between the developer electrode and bias voltage source. The preferred developer design is a micro-developer, having a plurality of electrode micro-regions that each adapt in bias to match the photoconductor voltage profile. The invented developer electrode design significantly reduces the backplating of toner on the electrode surface, and can be used to lengthen the available development time period for a given electrophotographic process.

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Boise, ID, United States of America

James A Kazakoff