Electrophotographic, resin-containing, electret, or inkjet compositions containing magenta azo pigment and use thereof

US6159649A · kind A · utility

Assignee

• Clariant Corporation · DE

Inventors

• Hans-Tobias Macholdt · Darmstadt, DE
• Dieter Baumgart · Egelsbach, DE
• Rudiger Baur · Eppstein, DE

Key dates

• Filing date: Sep 18, 1998
• Grant date: Dec 12, 2000
• Expiry date: Sep 18, 2018

Classification

• Technology area (CPC H): Electricity
• CPC primary: H01G7/021
• WIPO field: Basic materials chemistry
• WIPO sector: Chemistry

Abstract

The use of an azo pigment of the formula (1) ##STR1## as a colorant in electrophotographic toners, electrophotographic developers, powders and powder coatings, and electret materials, wherein said azo pigment is prepared in the presence of 20 to 50% by weight of an auxiliary selected from the group consisting of a rosin, a salt of a rosin, an abietic acid, and a salt of an abietic acid, wherein said weight is based on the overall weight of the azo pigment including said auxiliary, and wherein the azo pigment has a specific surface area of more than 70 m.sup.2 /g and the azo pigment particles comprising the azo pigment have a length-to-width ratio of on average less than 2.8:1 and a mean particle size d.sub.50 of less than 130 nm.