Magnetic developer for developing electrostatic images
US5364720A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 14, 1993 |
| Grant date | Nov 15, 1994 |
| Priority date | — |
| Expiry date | Oct 14, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03G9/08797
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A magnetic developer for developing electrostatic images is constituted by magnetic toner particles, each containing a binder resin having a melt viscosity of at most 5.0.times.10.sup.6 poise at 150.degree. C. and a magnetic material. The magnetic material is blended with a proportion (C) [wt. %] of inorganic fine particles based on the magnetic material to carry 0.2-5 wt. % of the inorganic fine particles secured to the magnetic material surface. The magnetic material has a specific surface area (A) [m.sup.2 /g] before securing of the inorganic fine particles and is provided with an increase in surface area (B) [m.sup.2 /g] by the securing of the inorganic fine particles; wherein the parameters A, B and C satisfy the following formulae (1) and (2): EQU 0.1.ltoreq.B/A.ltoreq.0.8 (1) EQU B<30.times.C (2). As a result, the magnetic developer is provided with an improved low-temperature fixability without causing problems accompanying the use of a low-temperature softening binder resin, such as deterioration of anti-offset characteristic, storage characteristic, developing characteristic.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.