CONTROL METHOD OF TRANSFER CURRENT AND IMAGE FORMING APPARATUS

• Main Authors: NAKAMURA KEIGO, AOKI SHINJI, IIMURA HARUO
• Format: Patent
• Language: English; Japanese
• Published: 21.12.2015
• Subjects: CINEMATOGRAPHY; ELECTROGRAPHY; ELECTROPHOTOGRAPHY; HOLOGRAPHY; MAGNETOGRAPHY; PHOTOGRAPHY; PHYSICS

PROBLEM TO BE SOLVED: To provide a control method of a transfer current, when controlling the transfer current according to an image area ratio, capable of suppressing an occurrence of image density variation due to response delay of a transfer electric field.SOLUTION: An image forming apparatus includes a primary transfer roller 25 for transferring a toner image carried on a photoreceptor 2 to an intermediate transfer belt 21. A target control value of a primary transfer current to be applied from a primary transfer power supply 81 to the primary transfer roller 25 is set as follows, where a C toner is cited as an example. A target control value ICt of the primary transfer current, when the primary transfer current is changed, is set by taking account of an image area ratio x1c of an area B as a prescribed area for passing through an outlet of a primary transfer nip and an image area ratio x0c of an area A as a downstream-side area to which the C toner image is transferred. 【課題】画像面積率に応じて転写電流を制御するときに、転写電界の応答遅延による、画像濃度変動の発生を抑制できる転写電流の制御方法を提供する。【解決手段】感光体２上に担持したトナー像を中間転写ベルト２１に転写する一次転写ローラ２５を備え、一次転写ローラ２５に対して、一次転写電源８１から印加される一次転写電流の目標制御値を、Ｃトナーを例に挙げると、次のようにして設定することとした。一次転写ニップの出口を通過する、所定領域である領域Ｂの画像面積率：ｘ１ｃと、Ｃトナー像が転写された下流側領域である領域Ａの領域の画像面積率：ｘ０ｃとを考慮して、一次転写電流を変化させるときの一次転写電流の目標制御値：ＩＣｔを設定する。【選択図】図７