Toner concentration sensor and toner concentration control method
US8380092B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 30, 2010 |
| Grant date | Feb 19, 2013 |
| Priority date | — |
| Expiry date | Oct 28, 2030 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03G15/0853
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
In this toner concentration sensor, as the magnetic permeability of a two-component developer 3 containing toner and carrier in a two-component developing unit 1 has changed with changing TC ratio of the two-component developer, the oscillation frequency of a first oscillation circuit 20 having a detection coil 5 changes, on the other hand the oscillation frequency of a second oscillation circuit 30 having a reference coil 6 does not change. While, changes in temperature conditions cause the oscillation frequency of the second oscillation circuit to change in the same way as the oscillation frequency of the first oscillation circuit. Therefore, utilizing a difference between the oscillation frequencies of the first and second oscillation circuits makes it possible to cancel out changes in the temperature conditions so that a value corresponding to only the magnetic permeability of the two-component developer can be obtained. Thus, detection errors of toner concentration due to temperature changes can be reliably prevented.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.