Patent ID: 9005864
Filing Date: 2015-04-14
Classification: G03G

Abstract:
1. A toner comprising: toner base particles; and an external additive, the toner base particles each comprising a binder resin and a colorant, wherein the external additive comprises non-spherical particles and spherical particles, wherein the spherical particles comprise dry silica, and have an average particle diameter of 10 nm to 35 nm, wherein the non-spherical particles comprise sol-gel silica and are each a secondary particle in which spherical primary particles are coalesced together, wherein the non-spherical particles have an average particle diameter of 60 nm to 480 nm, and wherein the non-spherical particles and the spherical particles in the external additive satisfy a relationship expressed by the following formula (1): where Ca is greater than 10% but smaller than 20% and Cb is greater than 40% but smaller than 70%, and Ca and Cb are values given by: where the surface area of the toner base particles is a value given by: 6/(an average particle diameter of the toner x a specific gravity of the toner); the projected area of the non-spherical particles is a value given by: 3/(2×an average particle diameter of the non-spherical particles x a specific gravity of the non-spherical particles); and the projected area of the spherical particles is a value given by: 3/(2×an average particle diameter of the spherical particles x a specific gravity of the spherical particles).