IMAGE FORMING APPARATUS

To provide an image forming apparatus that can estimate the state of deterioration of a cleaning blade.SOLUTION: An image forming apparatus 100 comprises: an image carrier 65; a developing device that has a developer carrier 641; a voltage application unit 121; a measuring unit 101; a cleaning blade that is in contact with the image carrier 65; and an estimation unit 102. The voltage application unit 121 applies, to the developer carrier 641, a bias voltage including a DC (direct current) bias and an AC (alternating current) bias. The measuring unit 101 measures a developing current Id flowing between the developer carrier 641 and the image carrier 65. The estimation unit 102 changes the DC bias to a first value and a second value, calculates a current ratio indicating the ratio between a first magnitude Id1 of the developing current Id with respect to the first value and a second magnitude Id2 of the developing current Id with respect to the second value Vdc2, and estimates the state of deterioration of the cleaning blade according to the value of the current ratio.SELECTED DRAWING: Figure 3 【課題】クリーニングブレードの劣化状態を推定することができる画像形成装置を提供する。【解決手段】画像形成装置１００は、像担持体６５と、現像剤担持体６４１を有する現像装置と、電圧印加部１２１と、測定部１０１と、像担持体６５に当接するクリーニングブレードと、推定部１０２とを備える。電圧印加部１２１は、ＤＣ（直流）バイアスとＡＣ（交流）バイアスとを含むバイアス電圧を現像剤担持体６４１に印加する。測定部１０１は、現像剤担持体６４１と像担持体６５との間に流れる現像電流Ｉｄを測定する。推定部１０２は、ＤＣバイアスを第１の値及び第２の値にそれぞれ変化させ、第１の値に対する現像電流Ｉｄの第１の大きさＩｄ１と、第２の値Ｖｄｃ２に対する現像電流Ｉｄの第２の大きさＩｄ２との比率を示す電流比率を算出し、電流比率の値に応じてクリーニングブレードの劣化状態を推定する。【選択図】図３