IMAGE FORMING APPARATUS

An image forming apparatus includes a first unit including means contributable to image formation; a second unit constituting a pair with the first unit and including means contributable to the image formation; a detecting device for detecting a degree of use of each of the first unit and the second unit, wherein limits of usability are predetermined for the first unit and the second unit, respectively; and a control device capable of outputting information signals for notifying states near the limits of usability on the basis of preset thresholds of degrees of use, respectively, wherein a number of capable image formations from an output of the signal indicating the near state for the first unit to the limit of usability of the first unit is larger than a number of capable image formations from an output of the signal indicating the near state for said second unit to the limit of usability of the second unit, and wherein the control device outputs the signal for the second unit when the degree of the second unit reaches a second threshold of degree, and the control device outputs the signal for the first unit when a condition that the degree of the first unit reaches a first threshold of degree of the first unit and a condition that the degree of the second unit reaches a second threshold of degree are satisfied.