ELECTRON EMISSION DEVICE, CHARGING DEVICE WITH THE ELECTRON EMISSION DEVICE, IMAGE FORMATION APPARATUS WITH THE ELECTRON EMISSION DEVICE, AND METHOD OF CONTROLLING THE ELECTRON EMISSION DEVICE

PROBLEM TO BE SOLVED: To provide an electron emission device capable of having its lifetime prolonged by stably controlling the charging amount and charging potential of an electron emission object such as a photoreceptor drum.SOLUTION: A control part 119 finds an estimated value MIe of a discharging current amount Ie corresponding to the amount (electron emission amount) of emitted electrons emitted from an electron emission element (111) based upon an in-element current amount Ip measured by an inflow ammeter 117 and a temperature T and a humidity H around the electron emission element 111 measured by an environment detection part 118, and controls a driving voltage Vd of a driving power source 115 so that the estimated value MIe reaches a target value AIe of the discharging current amount Ie. 【課題】感光体ドラム等の電子放出対象物の帯電量並びに帯電電位を安定制御し、装置の長寿命化を実現することが可能な電子放出装置を提供する。【解決手段】制御部１１９は、流入電流計１１７により測定された素子内電流量Ｉp及び環境検出部１１８により測定された電子放出素子１１１周辺の温度Ｔ及び湿度Ｈに基づき電子放出素子１１１から放出される放出電子の量（電子放出量）に対応する放出電流量Ｉeの推定値ＭＩeを求め、この推定値ＭＩeが放出電流量Ｉeの目標値ＡＩeとなるように駆動電源１１５の駆動電圧Ｖdを制御する。【選択図】図２