Hewlett-packard Development Company, L.p.

Hewlett-packard Company

Algird M Gudaitis

Tod S Heiles

Sam Michael Sarmast

Christopher M Lesniak

Dan Arquilevich

David K Klaffenbach

Rick Minoru Tanaka

Chadwick W Stryker

Stephen A Smith

Michael J Campin

Duane A Koehler

David E Smith

Christopher A Schantz

Wen-Li Su

Yifeng Wu

Ronald A Juve

Matias Negatu

Mark Jon Westlund

Jon S Boehm

William Lester Plishker

Kit Hui

A system includes a photodetector, a first amplifier, a second amplifier, and a filter. The photodetector is to detect backscattered light from liquid drops to provide a current signal. The first amplifier is to convert the current signal into a first voltage signal. The second amplifier is to amplify the first voltage signal to provide a second voltage signal, and the filter is to filter the second voltage signal to provide an output signal to indicate the presence or absence of liquid drops.

Liquid drop detection using backscattered light with amplifiers

A circuit includes a capacitive-type humidity sensor. The circuit provides start and stop signals to a processor in accordance with a charge voltage across the sensor. The processor performs a counting function to derive an integer count value in response to the start and stop signals. The processor uses the integer count value to determine parameters for controlling an ink-jetting print engine. Printing speed can be controlled in accordance with ambient humidity and/or temperature so that the printed media are sufficiently dried before handling by a user or other operations.

Control signaling using capacitive humidity sensor

A system is provided that includes an encoder strip having encoder markings, first and second optical encoders positioned at a fixed distance from one another on a substrate and, responsive to being moved along the encoder strip, configured to generate first and second signals, respectively, that each indicate detection of the encoder markings on the encoder strip and processing circuitry configured to determine a current phase difference between the first and the second signals using a first portion of the first signal that corresponds to a first plurality of encoder markings and a second portion of the second signal that corresponds to a second plurality of encoder markings.

Determining encoder strip expansion

This invention relates to a media jam and media bent corner detector, comprising: a carriage; a transducer operatively connected to or adjacent to the carriage; and a piezoelectric film beam operatively connected to the transducer such that a portion of the beam substantially extends into a media path to detect the presence of a media jam or a media bent corner.

Media jam and bent corner detector

Embodiments of power supply circuits are disclosed in which a filter function is performed on a count value from a counter that counts the number of times of enabling of a power supply circuit.

Power supply circuit

Apparatus and methods for color calibrating low cost sensors in a printing system are disclosed. Exemplary embodiments include printing targets from multiple printhead die; making multiple readings of each target; fitting a curve to the acquired data; and generating calibration coefficients based on the fitted curve. Exemplary embodiments may include a generic calibration to map sensor measurements to a colorimetric color space, and a specific calibration to account for sensor-to-sensor variation.

Apparatus and methods for color sensor calibration in a multi-die printer

Embodiments of a switching power supply circuit are disclosed wherein the number of times that a switch of the circuit is enabled is counted.

System and method for determining the power drawn from a switching power supply by counting the number of times a switching power supply switch is enabled

Correcting color values for color calibration is disclosed. A sensor measures a color calibration pattern output by a device, to color values for the patch. Corrective action(s) are then performed on the color values. A first such action corrects for measurement corruption of a patch color of the patch resulting from the sensor erroneously measuring adjacent patch colors to the desired patch color. A second action corrects for non-parallel motion of the sensor while measuring the patch. A third corrective action corrects for ambient light detected by the sensor while measuring the patch, without necessarily filtering the sensor. A final action corrects for slow-drift measurement corruption of the patch, by both scaling and offsetting the color values.

Color calibration color value correction

A method and apparatus for color measurement using a physically distributed multiplicity of sensors. Broad band illumination is provided to irradiate a test pattern. The sensors are used to measure color characteristics of discrete areas of a region of the pattern that has an intended single color by providing the pattern and sensors arrayed in a substantially matching geometric configuration.

Color measurement with distributed sensors in a color hard copy apparatus

A method, includes illuminating a first portion of a colored region with first light from a gas discharge tube and generating a first output using a diffuse reflection of the first light from the first portion. The method further includes illuminating a second portion of the colored region with second light from a first solid state lamp and generating a second output using a diffuse reflection of the second light from the second portion. Additionally, the method includes illuminating a third portion of the colored region with third light from a second solid state lamp and generating a third output using a diffuse reflection of the third light from the third portion.

Color measurement device and color measurement method

A compact optical sensing system is used in hardcopy devices for scanning and/or printing images, for instance, using inkjet printing technology in desktop printing or in photographic printers appearing in grocery and variety stores. Several light emitting diodes ('LEDs') illuminate a sheet of print media, and one or more photodiodes receive light reflected from the sheet. The photodiode generates signals in response to the light received, and the hardcopy device uses these signals to adjust printing parameters for optimal print quality. Using a chip-on-board process, the bare silicon die for each component is wire bonded directly to a printed circuit board assembly, allowing at least four LEDs (blue, green, red and soft-orange) to be grouped closely together in a space smaller than that occupied by a factory-made, single-packaged LED. A calibrating system uses a white target covered for cleanliness by a windowed door which is opened/closed by a printhead carriage.

Compact optical sensing system

A compact optical sensing system is used in hardcopy devices for scanning and/or printing images, for instance, using inkjet printing technology in desktop printing or in photographic printers appearing in grocery and variety stores. Several light emitting diodes (&ldquo;LEDs&rdquo;) illuminate a sheet of print media, and one or more photodiodes receive light reflected from the sheet. The photodiode generates signals in response to the light received, and the hardcopy device uses these signals to adjust printing parameters for optimal print quality. Using a chip-on-board process, the bare silicon die for each component is wire bonded directly to a printed circuit board assembly, allowing at least four LEDs (blue, green, red and soft-orange) to be grouped closely together in a space smaller than that occupied by a factory-made, single-packaged LED. A calibrating system uses a white target covered for cleanliness by a windowed door which is opened/closed by a printhead carriage.

Tuning system for a compact optical sensor

Calibrating system for a compact optical sensor

A pen alignment method for a multi-pen printer is provided, the method including directing a first pen to print a first pattern of a first color, directing a second pen to print a second pattern of a second color in a predetermined relative alignment with the first pattern to form a test block, determining an actual hue of the test block via spectral analysis of the test block using a color sensor, and comparing the actual hue of the test block with an expected hue of the test block to determine whether the first and second pens are misaligned relative to each other, wherein the expected hue of the test block is the hue that would be detected if the first pen and second pen were correctly aligned.

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Vancouver, WA, United States of America

Algird M Gudaitis