Image forming apparatus and toner cartridge

Abstract

An image forming apparatus includes an image carrier; a charging section that charges the surface of the image carrier; an electrostatic-charge-image-forming section that forms an electrostatic charge image on the charged surface of the image carrier; a developing section that contains toner for electrostatic charge image development and develops the electrostatic charge image on the surface of the image carrier into a toner image using the toner; a replenishment toner supplying section that supplies the toner to the developing section, the replenishment toner supplying section including a replenishment toner cartridge, the replenishment toner cartridge containing the toner, having a cap and a body, and detachably attached to the image forming apparatus, the cap being at a first axial end of the replenishment toner cartridge and having an outlet for the replenishment toner to be ejected therethrough, whereas the body having a ridged portion by which the toner inside is moved in the direction from a second axial end of the replenishment toner cartridge to the outlet as the body rotates; a transfer section that transfers the toner image formed on the surface of the image carrier to the surface of a recording medium; and a fixing section that fixes the toner image transferred to the surface of the recording medium. The toner satisfying the following relations: (ln η(T)−ln η(T))/(T−T)≤−0.14; (ln η(T)−ln η(T))/(T−T)≥−0.15; and (ln η(T)−ln η(T))/(T−T)<(ln η(T)−ln η(T))/(T−T), where η(T) represents a viscosity of the toner at 60° C., η(T) represents a viscosity of the toner at 90° C., and η(T) represents a viscosity of the toner at 130° C.