Mita Industrial Co., Ltd.

Tadashi Sakuma

Hideo Nakamori

Eiichi Miyamoto

Mikio Kakui

Hiroaki Iwasaki

Masashi Tanaka

Keizo Kimoto

Maki Uchida

Yukikatsu Imanaka

Nariaki Tanaka

Toshiyuki Fukami

Yasuyuki Hanatani

Hiroshi Takemoto

Nobuyuki Kashiwagi

Yuka Nakamura

Youichi Takesawa

A photosensitive drum unit for an electrostatographic printing apparatus is disclosed. The drum unit includes a drum tube formed with at least one opening at one axial end thereof. A flange member is configured to be inserted into the opening in the drum tube. The flange member is provided with a support hole into which a shaft pin is inserted for supporting the drum tube and flange member. An earth plate is formed with projections or claws that extend radially outward from a peripheral edge of the earth plate such that the projections contact with an inner peripheral surface of the drum tube. The earth plate is also formed with a pair of contact pieces extend axially away from the earth plate and also extend toward one another. The contact pieces are spaced apart from one another by a predetermined distance but are also configured to contact and engage a portion of the shaft pin.

Drum unit and earth plate used in the drum unit

The present invention provides a novel naphthylenediamine derivative which is superior in electric charge transferring capability, compatibility with binding resin and stability, and an electrophotosensitive material which has a higher sensitivity and an excellent durability. The above naphthylenediamine derivative is represented by the following general formula (1), and the electrophotosensitive material is formed by providing a photosensitive layer having this naphthylenediamine derivative as an electric charge transferring material on a conductive substrate. ##STR1## wherein R.sup.1 to R.sup.4, R.sup.5a to R.sup.5f and a to d are as defined.

Naphthylenediamine derivative and electrophotosensitive material using

The present invention provides a novel naphthylenediamine derivative which is superior in electric charge transferring capability, compatibility with binding resin and stability. The above naphthylenediamine derivative is represented by the following general formula (1) ##STR1## wherein R.sup.1 to R.sup.4, R.sup.5a to R.sup.5f and a to d are as defined.

Naphthylenediamine derivative

The organic photosensitive material for electrophotography in accordance with this invention is characterized in that a non-symmetrically substituted diphenoquinone derivative represented by the following formulae ##STR1## wherein each of R.sub.1 and R.sub.2 represents an alkyl or aryl group, R.sub.2 having larger carbon atoms than R.sub.1, is used as an electron transporting agent. This photosensitive material has a residual potential limited to a low level, and shows excellent sensitivity in both positive charging and negative charging.

Electrophotographic organic photosensitive material with diphenoquinone

Disclosed is a laminate type photosensitive material for the electrophotography, which comprises a charge-generating layer and a charge-transporting layer, which are formed on an electroconductive substrate, wherein the charge-transporting layer comprises a first charge-transporting material having an ionization potential smaller than that of a charge-generating material used for the charge-generating layer and a second charge-transporting material having an ionization potential larger than that of the charge-generating material. In this photosensitive material, by using a charge-transporting material having an ionization potential larger than that of the charge-generating material in combination with the charge-transporting material having an ionization potential smaller than that of the charge-generating material, a good residual potential can be maintained without disturbing injection of holes in the charge-transporting layer, the stability of the surface potential at the repeated use is improved and a good charging capacity can be attained.

Laminate type photosensitive material for electrophotography

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Sakai, Japan

Tadashi Sakuma