Patent ID: 6103440
Filing Date: 2000-08-15
Classification: G03G

Abstract:
A toner comprised of toner particles consisting essentially of a melt mixture of resin particles, an internal charge additive, and an internal release agent, wherein the toner resin is a styrene-butadiene copolymer with a weight average molecular weight of about 100,000 to about 400,000 in an amount of from about 55 to about 70 weight percent, the colorant is mixture of an acicular magnetite in an amount of from about 27 to about 34 weight percent and carbon black in an amount of from about 2 to about 3 weight percent based on the total weight of the toner composition, wherein the internal charge additive is quaternary ammonium salt in an amount of from about 0.7 to about 1.5 weight percent, wherein the internal release agent is a low molecular weight wax with a weight average molecular weight of from about 1,000 to about 3,000 in an amount of from about 4.5 to about 6 weight percent; and the surface of the toner particles consists of a mixture of a hydrophobic silica flow aid compound in an amount of from about 0.75 to about 1.0 weight percent, strontium titanate in an amount of from about 0.5 to about 1.25 weight percent, and polymethylmethacrylate surface additive particles electrostatically adhering to the surface of said toner particles in an amount of from about 0.25 to about 0.75 weight percent based on the total weight of the toner, wherein the toner has a net positive charging character, and wherein the background deposits (BKG) and solid area development (SAD) components of the machine toner concentration latitude of said toner composition is in the range of about 4 to about 5 units compared to a range of about 1 to about 1.5 units for a toner without said polymethylmethacrylate particles on the surface of the toner.