| 摘要 |
PROBLEM TO BE SOLVED: To accurately measure the amount of a developer in a developing unit irrespective of the influence of external environment.SOLUTION: A printer 1 of the present invention includes a developing unit 9 that develops a photoreceptor drum 7 with a toner stored therein, a toner sensor 28 that detects the magnetic permeability of the toner in the developing unit 9, and a toner amount measuring unit 46 that calculates the duty ratio of the magnetic permeability of the toner in the developing unit 9 on the basis of the result of the detection by the toner sensor 28, and measures the amount of the toner in the developing unit 9 on the basis of the duty ratio. |
