Electrostatographic developer composition

US5545501A · kind A · utility

Assignee

• Agfa-Gevaert NV · BE

Inventors

• Serge Tavernier · Lint, BE
• Frank Ruttens · Overijse, BE
• Andr e Verhecken · Mortsel, BE
• Jozef L. Mampaey · Kontich, BE
• Ludovicus Joly · Hove, BE

Key dates

• Filing date: Dec 6, 1994
• Grant date: Aug 13, 1996
• Expiry date: Dec 6, 2014

Classification

• Technology area (CPC G): Physics
• CPC primary: G03G9/10
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

This invention provides an electrostatographic developer composition comprising carrier particles and toner particles with a toner particle size distribution having a volume average particle size (T) such that 4 m.mu..ltoreq.T.ltoreq.12 .mu.m and an average charge (absolute value) pro diameter in femtocoulomb/10 .mu.m (C.sub.T) after triboelectric contact with said carrier particles such that 1 fC/10 .mu.m.ltoreq.C.sub.T .ltoreq.10 fc/10 .mu.m characterised in that PA1 (i) said carrier particles have a saturation magnetization value, M.sub.sat, expressed in Tesla (T) such that M.sub.sat .gtoreq.0.30 T PA1 (ii) said carrier particles have a volume average particle size (C.sub.avg) such that 30 .mu.m.ltoreq.C.sub.avg .ltoreq.60 .mu.m PA1 (iii) said volume based particle size distribution of said carrier particles has at least 90% of the particles having a particle diameter C such that 0.5 C.sub.avg .ltoreq.C.ltoreq.2C.sub.avg PA1 (iv) said volume based particles size distribution of said carrier particles comprises less than b % particles smaller than 25 .mu.m wherein b=0.35.times.(M.sub.sat).sup.2 .times.P with PA2 M.sub.sat : saturation magnetization value, M.sub.sat, expressed in …