Toner having improved charge characteristics
View Patent ↗This invention provides a toner with improved charge and charge stability by suitable addition of extra particulate additives (EPA) such as aluminum cerium oxide and/or cerium zirconium oxide. The additives may be combined with toner in a conical mixer having selected temperature control. The invention also provides toner which may provide reduced print quality defects such as ghosting or residual image and fade-to-color.
1. An electrophotographic toner composition comprising:
toner particles;
at least one particulate metal oxide dispersed with the toner particles, wherein the metal oxide is selected from the group consisting of aluminum cerium oxide having the formula AlCeO 3 , cerium zirconium oxide having the formula (CeO 2 ).(ZrO 2 ) and combinations thereof, and the metal oxide content is from 0.05 to 1.0 weight percent of the toner composition; and
silica oxide and titania are each present at a combined weight of less than 5% of the weight percent of the toner composition, wherein the titania include an acicular titanium oxide and strontium titanate.
2. The toner composition of claim 1 wherein said metal oxide content is from 0.05 to 0.5 weight percent of the toner composition.
3. The toner composition of claim 1 wherein said metal oxide content is from 0.05 to 0.25 weight percent of the toner composition.
4. The toner composition of claim 1 wherein the particle size for the metal oxides is >50 nm.