IMAGE FORMING APPARATUS

To predict an appropriate replacement time of a charging member by using the amount of a current flowing when a predetermined applied voltage is applied to the charging member.SOLUTION: An image forming apparatus comprises: current detection means 21 that detects the amount of a current Idc flowing when a predetermined applied voltage Vc is applied to a charging member 123a that, upon application of a predetermined charging voltage, charges a surface of an image carrier 122; and prediction means 10 that predicts a replacement time of the charging member by using the current amount detected by the current detection means. The prediction means calculates the capacitance C of the image carrier from the applied voltage Vc applied to the charging member and the current amount Idc detected by the current detection means, and executes prediction processing of predicting the replacement time of the charging member by using the calculated capacitance C and the current amount Idc detected by the current detection means.SELECTED DRAWING: Figure 3 【課題】帯電部材に対して所定の印加電圧を印加した時に流れる電流量を用いて、帯電部材の適切な交換時期を予測する。【解決手段】所定の帯電電圧が印加されることで像担持体１２２の表面を帯電させる帯電部材１２３ａに対して所定の印加電圧Ｖｃを印加した時に流れる電流量Ｉｄｃを検知する電流検知手段２１と、前記電流検知手段が検知した電流量を用いて前記帯電部材の交換時期を予測する予測手段１０とを有する画像形成装置において、前記予測手段は、前記帯電部材に印加した印加電圧Ｖｃと前記電流検知手段が検知した電流量Ｉｄｃとから前記像担持体の静電容量Ｃを算出し、算出した静電容量Ｃと、前記電流検知手段が検知した電流量Ｉｄｃとを用いて、前記帯電部材の交換時期を予測する予測処理を実行する。【選択図】図３