Hewlett-Packard Development Company, L.p.

Matthew James West

Jose Miguel Rodriguez

Cesar Fernandez Espasa

Matthew J Gelhaus

Tanner D Christensen

In an example of the disclosure, power of a first light beam emitted across a web media along a length of the roller is measured utilizing a first optical transmitter and first optical receiver pair situated adjacent to a roller. Power of a second light beam emitted across a length of the roller is measured utilizing a second optical transmitter and second optical receiver pair situated adjacent to the roller. A media height non-uniformity is identified based upon of the measurement of the power of the first light beam and the measurement of the power of the second light beam.

Media height non-uniformity detection

According to examples, an apparatus may include a processor and a memory on which are stored machine readable instructions. The instructions, when executed by the processor, may cause the processor to access a property value respectively corresponding to each of a plurality of firing actuators in a printing system and determine a count of the firing actuators having property values that are outside of a predefined threshold value range. Based on the count exceeding a predefined maximum threshold value, the instructions may cause the processor to determine locations of the plurality of the firing actuators having property values that are outside of the predefined threshold value range, determine a standard deviation of the determined locations, and based on the determined standard deviation being below a predetermined threshold, output an indication concerning a potential printhead strike.

Potential printhead strike determination

In example implementations, a fluid ejection system is provided. The fluid ejection system includes a plurality of fluid ejection devices, a sensor and a feedback system. The plurality of fluid ejection devices can distribute fluid onto a media. The sensor may analyze a line of an image formed by the fluid on the media. The feedback system can determine a respective amount of time delay for each one of the plurality of fluid ejection devices based on the line of the image on the media that is analyzed by the sensor. The respective amount of time delay is inserted into at least one sideband signal to provide a correct alignment of the fluid ejection devices when printing a subsequent line of the image on the media.

Sideband signal for fluid ejection

Methods and apparatus are provided related to testing electrical connectivity. A sequence of distinct test data signal patterns is issued. The test data signals are propagated by way of respective pathways and electrical connectors. A feedback signal is generated in accordance with a test function for each of the test data signal patterns. A test results message is generated in accordance with the feedback signals, which can include specific diagnostic or identifying information.

Electrical connectivity test apparatus and methods

Embodiments of modifying data are disclosed.

Growing community of inventors

Corvallis, OR, United States of America

Matthew James West