In one embodiment, a pixel count portion that accumulates pixel count values for each pixel obtained by multiplying the input signal levels of a multilevel image by weighting coefficients, a toner consumption calculating portion that calculates toner consumption of each color from the pixel count sum value, an average toner consumption calculating portion that calculates average toner consumption per page based on the total amount of toner consumption and total number of pages printed subsequent to shipment, and a remaining toner calculating portion that calculates the amount of remaining toner from the total toner consumption based on the sum total of divided regions since the most recent time that a toner cartridge was exchanged, are provided, and a control portion executes a toner saving mode when the amount of remaining toner calculated by the remaining toner calculating portion reaches not more than a predetermined value set in advance.