Calibrated apparent surface voltage measurement apparatus and method
US4433298A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 12, 1981 |
| Grant date | Feb 21, 1984 |
| Priority date | — |
| Expiry date | Nov 12, 2001 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R29/24
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The disclosed calibrated ASV measurement apparatus provides accurate measurements of the ASV (apparent surface voltage) on a photoconductive imaging medium using a relatively low cost, commercially available ASV probe. To obtain accurate ASV measurements, the probe sensitivity (relating probe voltgage output to sensed potential) is periodically recalibrated to compensate for changes in environmental and electrical conditions. The calibration function is implemented using a calibration target mounted directly to the housing of the probe's sensing head so as to occupy a portion of the probe's sensing field. During periodic calibration intervals, when the ASV probe is responsive only to potentials on the calibration target, known potentials are applied to the calibration target, and an indication of a change in probe sensitivity with respect to the calibration target is calculated and used to recalibrate the value for probe sensitivity used in ASV measurement. During periodic ASV measurement intervals (with the calibration target at ground potential), the ASV probe is exposed to a reference ground and to the ASV on the imaging medium to obtain a differential probe voltgage, and this d…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.