Charging device and electrophotographic apparatus including the same
AssigneeSharp Kabushiki Kaisha
InventorsToshiki Takiguchi, Tatsuya Inoue, Hirokazu Yamauchi, Kazuhiro Matsuyama, Yasuhiro Takai
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Abstract
In an image forming apparatus of the present invention, a scorotron charging device has a meshed grid electrode which is meshed more coarsely in a high-speed apparatus than a meshed grid electrode in a low-speed apparatus according to a circumferential velocity of a photoreceptor. With this arrangement, it is possible to charge the photoreceptor at a predetermined potential in the high-speed apparatus, without increase of the amount of ozone generation and upsizing of the image forming apparatus.
Claims5
A charging device which is installed in an electrophotographic apparatus and charges at a predetermined potential a surface of an electrostatic latent image carrier which is driven for rotation,
- the charging device comprising:
- at least one wire which is subjected to application of a high voltage and placed at a position that faces the electrostatic latent image carrier so that an axial direction of the wire is orthogonal to a rotational direction of the electrostatic latent image carrier;
- a shield electrode which shields the wire and has an open surface that faces the electrostatic latent image carrier;
- and
- a meshed grid electrode which is placed so as to face the open surface of the shield electrode, wherein:
- the grid electrode is arranged to be a fine-meshed grid electrode as a circumferential velocity of the electrostatic latent image carrier is low, and to be a coarse-meshed grid electrode as a circumferential velocity of the electrostatic latent image carrier is high.
An electrophotographic apparatus comprising:
- an electrostatic latent image carrier which retains an electrostatic latent image formed on a surface thereof and is driven for rotation;
- and a charging device which charges a surface of the electrostatic latent image carrier at a predetermined potential,
- the charging device being realized by one scorotron charger,
- the scorotron charger comprising:
- at least one wire which is subjected to application of a high voltage and placed at a position that faces the electrostatic latent image carrier so that an axial direction of the wire is orthogonal to a rotational direction of the electrostatic latent image carrier;
- a shield electrode which shields the wire and has an open surface that faces the electrostatic latent image carrier;
- and
- a meshed grid electrode which is placed so as to face the open surface of the shield electrode, wherein:
- the grid electrode is arranged to be a fine-meshed grid electrode as a circumferential velocity of the electrostatic latent image carrier is low, and to be a coarse-meshed grid electrode as a circumferential velocity of the electrostatic latent image carrier is high.
Dependencies are inferred from the claim text.