Magnetic black toner and multi-color or full-color image forming method
US5840457A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 30, 1997 |
| Grant date | Nov 24, 1998 |
| Priority date | — |
| Expiry date | Jul 30, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03G2215/0174
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A magnetic black toner for electrophotography, includes: (a) magnetic black toner particles containing a binder resin, a magnetic material in 30-200 wt. parts per 100 wt. parts of the binder resin, and a first solid wax, and (b) first inorganic fine powder. The first solid wax (ii) provides a DSC heat-absorption main peak in a range of 60.degree.-120.degree. C., and (iii) shows a molecular weight distribution factor Mw/Mn of 1.0-2.0. The binder resin (iv) has a THF (tetrahydrofuran)-insoluble content of at most 5 wt. %, and (v) contains a THF-soluble content showing a GPC molecular weight distribution including a content (M1) of 40-70% in molecular weights of below 5.times.10.sup.4, a content (M2.ltoreq.M1) of 20-45% in molecular weights of 5.times.10.sup.4 -5.times.10.sup.5, and a content (M3<M2) of 2-25% in molecular weights exceeding 5.times.10.sup.5. (vi) The magnetic black toner exhibits a tan .delta. of 0.5-3.0 in a range of 150.degree.-190.degree. C. and a tan .delta. at 150.degree. C. that is equal to or larger than a tan .delta. at 100.degree. C. The magnetic black toner shows a good fixability in an oil-less fixation system to provide a fixed image having a gloss comparab…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.