Developing device using a two-ingredient type developer and image forming apparatus including the same
US6873814B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 1, 2002 |
| Grant date | Mar 29, 2005 |
| Priority date | — |
| Expiry date | Nov 6, 2022 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03G13/09
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A developing device including a developer containing magnetic toner grains and includes a main pole for development disposed in a sleeve. Flux density generated by the magnetic pole in a direction normal to the surface of the sleeve outside of the surface has an attenuation ratio of 50% or above. The toner grains have a weight mean grain size of 6.0 μm to 8.0 μm while the toner grains having grain sizes of 5 μm and below occupy 40% to 80% of the entire developer. The toner grains have magnetization strength of 10 emu/g to 25 emu/g in a magnetic field of 5 kOe or magnetization strength of 7 emu/g to 20 emu/g in a magnetic field of 1 kOe. The toner grains reduce toner scattering and image defects despite that they are magnetic, thereby implementing ultrahigh resolution.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.