Matsushita Electric Industrial Co., Ltd.

Junichi Nawama

Akira Kumon

Yoshio Umeda

Seiichi Suzuki

Toshiki Yamamura

Teruyuki Naka

Katsutoshi Ogawa

Hisanori Nagase

Noboru Katakabe

Masaichiro Tatekawa

Masahiro Aizawa

Hitoshi Hisada

In a color electrophotographic printer, an intermediate transfer belt is provided to layer toner images of a plurality of colors, and the toner images on the belt are transferred onto a paper sheet. In order to remove a paper sheet when a paper jam happens, a door is provided in a case of the printer, while a cover is provided to protect a transfer region where the intermediate transfer belt contacts with a paper sheet for transferring the toner images. When the door is opened, the cover moves to cover a portion of the surface of the intermediate transfer belt exposed to the door. When the jammed paper sheet is removed, the image forming process is resumed immediately on the toner images on the intermediate transfer belt. Further, an intermediate transfer unit including the intermediate transfer belt and the cover detachable from the printer may be provided. In a modified example, a transfer member which is connected to a transfer member is provided instead of the cover, and when the door is opened, the transfer member covers the surface of the intermediate transfer belt.

Image forming apparatus having a cover for protecting a transfer region

A charging device for charging a movable object to be charged. A charging member contacts the object to be charged. A power source applies a voltage to the charging member, wherein the power spectrum PS satisfies the following relation when the space frequency of the profile of the surface of the charging member is analyzed. In the section of 10.ltoreq.f.ltoreq.100 (cycles/mm):

Charging device and an image forming apparatus using a charging device

A charging device for charging a moving photoconductor. The charging device includes a charging member, an electric power supply for applying a voltage to the charging member, and a light exposing device, such as a LED for exposing surfaces of the charging member and the photoconductor in a closing region where the surfaces of the charging member and the photoconductor move closer to each other. The charging member is a blade having a transparent layer for guiding a light beam from the LED to the closing region and a shading layer for shading the light beam to a contacting region and a separating region. The contacting region is where the surfaces of the charging member and the photoconductor contact, and the separating region is where the surfaces of the charging member and the photoconductor gradually separate from each other. The LED is disposed in the vicinity of an end of the transparent layer opposite to the other end in the closing region in a section parallel to the moving direction of the photoconductor.

Charging device and image forming apparatus containing the charging

A color image forming apparatus forming toner images of yellow, magenta, cyanogen and black respectively by rotational movement of different image forming units is described. The toner images are transferred to and superimposed on an intermediate transfer belt and then re-transferred to a paper sheet by pressing a transfer roller on the intermediate transfer belt via the paper sheet. A rotational axis of the transfer roller is immovable, and a potential of the transfer roller is electrically floated while the toner images are transferred to the intermediate transfer belt.

Color image forming apparatus and method having toner images transferred

A charging member for charging a photosensitive member from above toner in an electrophotographic process in which charging, exposure, development, and transfer steps are performed repeatedly and in which a step of cleaning toner remaining on a photosensitive member is eliminated, the charging member including: an electrically conductive charging wire which is disposed in contact with the photosensitive member; the charging wire forming an angle of less than 90.degree. with a direction of a rotational axis of the photosensitive member and is arranged at an interval in the direction of the rotational axis of the photosensitive member; and a power source for applying a pulse voltage to the charging wire, the pulse voltage having a polarity identical with that of the toner so as to vibrate the toner.

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Osaka, Japan

Junichi Nawama