Ricoh Company, Ltd.

Yoshihiko Iijima

Yukimichi Someya

Takuro Sekiya

Yasuo Katano

Naomi Sugimoto

Toshihiro Ishii

Eiichi Ohta

Shohji Tanaka

An electric charging apparatus charges a surface of a charging object. The electric charging apparatus includes an electric field forming device including two electrodes facing each other that form an electric field therebetween. An electron discharging member is provided at a portion of one of the two electrodes that faces the other electrode and discharges electrons into the electric field. The electric charging apparatus also includes a voltage applying controller that controls a voltage applied to the two electrodes. The voltage applying controller selects two or more nonzero intensities of the electric field.

Electric charging apparatus and image forming apparatus using the same

An electron emission element according to the present invention is compact, thin and low cost, and has a structure and constitution in which deterioration of the electron emission material itself is low. In the electron emission element, boron nitride material is used as the electron emission material, and a metal material or a semiconductor material is used as a substrate for forming the boron nitride material. In this way it is possible to obtain good quality boron nitride material on the substrate. Also, a voltage can be applied to the material to emit electrons, also electrons can be supplied. Moreover, by using Sp-bonded boron nitride as the boron nitride material, and using Sp-bonded 5H&#x2014;BN material or Sp-bonded 6H&#x2014;BN material as the Sp-bonded boron nitride, a field electron emission element can be achieved for which high efficiency electron emission characteristics unprecedented in conventional art can be obtained.

Electron emission element, charging device, process cartridge, and image forming apparatus

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Sendai, Japan

Yoshihiko Iijima