Method of detecting a toner concentration
US4054230A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 6, 1976 |
| Grant date | Oct 18, 1977 |
| Priority date | — |
| Expiry date | Apr 6, 1996 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S222/01
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
The method detects a toner concentration in a developer comprising a mixture of magnetic carrier particles and a non-magnetic toner through the determination of a leakage magnetic flux with a Hall element having a high sensitivity. The mixture is first shaped into a predetermined configuration and brought into a fixed magnetic field where the leakage magnetic flux is sensed by the Hall element. The shaped mixture may be a magnetic brush per se in case of the well-known magnetic brush device used. Such a Hall element is very susceptible to a variation of environmental temperature and thus requires a compensation therefor upon the determination of magnetic field. In one aspect of the invention, the compensation may be conveniently achieved by detecting a voltage across the control current terminals of the Hall element and supplying the detected result into an input of analog calculator.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.