Electrophotographic toner
US6824945B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 7, 2003 |
| Grant date | Nov 30, 2004 |
| Priority date | — |
| Expiry date | Jul 7, 2023 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03G9/09
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
Disclosed is an electrophotographic toner using a polyester resin as a binder and a highly dispersed pigment colorant. The toner gives a high quality image excellent in transparency and chroma (brightness, gloss) and exhibits excellent powder fluidity, anti-offset property, charge stability and transferability.The toner is obtained by dispersing an oil dispersion, containing an isocyanate group-containing polyester prepolymer dissolved in an organic solvent, a pigment colorant dispersed therein and a releasing agent dissolved or dispersed therein, in an aqueous medium in the presence of inorganic fine particles and/or polymer fine particles, reacting the prepolymer in the dispersion with a polyamine and/or a monoamine containing an active hydrogen-containing group to form an urea-modified polyester resin having an urea group, and by removing the liquid medium from the dispersion containing the urea-modified polyester resin, and is characterized in that the pigment colorant contained in the toner has a dispersion diameter, in terms of a number average diameter, of 0.5 &mgr;m or less and in that particles of the pigment colorant having a diameter of 0.7 &mgr;m or more account for 5% …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.