Electrophotographic apparatus, image forming method and process cartridge
US6026260A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 20, 1998 |
| Grant date | Feb 15, 2000 |
| Priority date | — |
| Expiry date | Oct 20, 2018 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S430/102
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An electrophotographic apparatus includes: an electrophotographic photosensitive member, a charging device including a charging member formed of magnetic particles and disposed contactable to the photosensitive member so as to charge the photosensitive member based on a voltage applied thereto, exposure device, developing device, and a transfer device. The magnetic particles exhibit a good charging ability for a long period and therefore provide a good continuous image-forming performance because they are formed of ferrite particles including a ferrite having a very limited composition represented by the formula of: EQU (MnO).sub.x (MgO).sub.y (Fe.sub.2 O.sub.3).sub.z, wherein x, y and z are numbers satisfying x+y+z.ltoreq.1, 0.2<x<0.5, 0.05<y<0.25 and 0.4<z<0.6, and 0.01-3 wt. parts of phosphorus added per 100 wt. parts of the ferrite and contained preferentially at a larger concentration at the surfaces of the magnetic particles than in the entirety of the magnetic particles.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.