Liquid developer charge director control
US4860924A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 25, 1988 |
| Grant date | Aug 29, 1989 |
| Priority date | — |
| Expiry date | Jul 25, 2008 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S222/01
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A copier wherein charge director is supplied to a liquid developer in response to a conductivity measurement thereof. Toner concentrate deficient in charge director is supplied to the liquid developer in response to an optical transmissivity measurement thereof. Conductivity is measured by a pair of spaced electrodes immersed in the developer and through which a variable alternating current is passed. A variable capacitor neutralizes the inherent capacitance of the electrodes. A phase sensitive detector is provided with a reference voltage having the same phase shift as that caused by capacitive effects. The conductivity measurement is corrected in response to a developer temperature measurement.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.