IMAGE FORMING APPARATUS

To prevent, in removing an excess external additive attached to an image holding body, acceleration of adhesion of the external additive, compared with the case where a discharge bias applied to a charger is maintained the same as that during image formation.SOLUTION: While an image forming operation is not executed, an image forming apparatus (U) executes external additive removal processing of rotating image holding bodies (Py to Pk) while a discharge bias applied to discharge members (CRy to CRk, Jy to Jk) is reduced compared with that during image formation, and sets execution time of the external additive removal processing (t1) according to an amount of an external additive attached to the image holding bodies (Py to Pk).SELECTED DRAWING: Figure 5 【課題】像保持体に付着した過剰な外添剤を除去する際に、帯電器へ印加される放電バイアスを画像形成時と同一の状態に維持する場合に比較して、外添剤の固着の促進を抑制すること。【解決手段】画像形成動作が実行されていない状態で、放電部材（ＣＲｙ〜ＣＲｋ、Ｊｙ〜Ｊｋ）へ印加される放電バイアスを画像形成時よりも低くした状態で像保持体（Ｐｙ〜Ｐｋ）を回転させる外添剤の除去処理を実行すると共に、外添剤の除去処理の実行時間（ｔ１）を、像保持体（Ｐｙ〜Ｐｋ）に付着している外添剤の量に応じて設定することを特徴とする画像形成装置（Ｕ）。【選択図】図５