Back to results
US 2014/0209787 A1Published application
Liquid drop detection
AssigneeHewlett-Packard Development Company, L.P.
InventorsAlgird M. Gudaitis, David E. Smith
Life of this patent
Estimating the term…
Abstract
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.
Claims15
A system comprising:
- a photodetector to detect backscattered light from liquid drops to provide a current signal;
- a first amplifier to convert the current signal into a first voltage signal;
- a second amplifier to amplify the first voltage signal to provide a second voltage signal;
- and
- a filter to filter the second voltage signal to provide an output signal to indicate the presence or absence of liquid drops.
2 more elements
A printer comprising:
- a plurality of photodiodes to detect backscattered light from ink drops;
- a plurality of transimpedance amplifiers, each transimpedance amplifier to convert a current signal from a respective photodiode into a respective first voltage signal;
- a summing amplifier to receive the first voltage signal from each transimpedance amplifier to provide a second voltage signal;
- and
- an output filter to filter the second voltage signal to provide an output signal to indicate the presence or absence of ink drops.
2 more elements
An ink drop detector comprising:
- a plurality of photodiodes to detect backscattered light from ink drops;
- a plurality of transimpedance amplifiers, each transimpedance amplifier to convert a current signal from a respective photodiode into a respective first voltage signal, each transimpedance amplifier having an AC gain at least 20 times greater than a DC gain of each transimpedance amplifier;
- an AC-coupled summing amplifier to receive the first voltage signals to provide a second voltage signal, the AC-coupled summing amplifier having a gain set to create full scale second voltage signal swings without clipping at either voltage rail of the summing amplifier even when a combination of desired and undesired signals is present;
- and
- a 2-pole, low pass output filter to filter the second voltage signal to provide an output signal to indicate the presence or absence of ink drops.
2 more elements
Dependencies are inferred from the claim text.