Image forming apparatus
An image forming apparatus includes a developer tank which houses two-component developer containing toner and carrier, and a supply unit which supplies the developer tank with supply developer containing toner and carrier, wherein, when the ratio of mass of inorganic fine particles attached to the carrier contained in the two-component developer to mass of the carrier contained in the two-component developer is A, and when the ratio of mass of inorganic fine particles attached to the carrier contained in the supply developer to mass of the carrier contained in the supply developer is B, the following Formula (1) is satisfied: 0.7< B/A <0.96 (1).
1. An image forming apparatus, comprising:
a developer tank that houses a two-component developer containing toner and carrier; and
a supply unit that supplies the developer tank with supply developer containing toner and carrier,
wherein the toner contained in the two-component developer contains toner mother particles, and inorganic fine particles that are externally added to the toner mother particles,
the toner contained in the supply developer contains toner mother particles, and inorganic fine particles that are externally added to the toner mother particles,
the inorganic fine particles are silicon dioxide particles,
the toner contained in the two-component developer is the same as the toner contained in the supply developer,
the carrier contained in the two-component developer is identical to the carrier contained in the supply developer with respect to composition, but has been treated to have a rougher surface, and
wherein, when the ratio of mass of inorganic fine particles attached to the carrier contained in the two-component developer to mass of the carrier contained in the two-component developer is A, and the ratio of mass of inorganic fine particles attached to the carrier contained in the supply developer to mass of the carrier contained in the supply developer is B,
the following Formula (I) is satisfied:
0.7 <B/A< 0.96 (1).
2. The image forming apparatus according to claim 1 ,
wherein the inorganic fine particles attached to the carrier contained in the two-component developer are formed by the transfer of the inorganic fine particles contained in the toner in the two-component developer to the carrier, and
the inorganic fine particles attached to the carrier contained in the supply developer are formed by the transfer of the inorganic fine particles contained in the toner in the supply developer to the carrier.
3. The image forming apparatus according to claim 1 ,
wherein the content of the carrier in the supply developer is 1 to 20 parts by mass relative to 100 parts by mass of the toner.