Ricoh Company, Ltd.

Shingo Katou

Nobuo Iwata

Tomonori Yabuta

Shigeo Kurotaka

Takahiro Tamiya

Yutaka Shio

Tsuyoshi Deki

Takeshi Motohashi

A full-color image forming apparatus having a photo-conductive belt on which mono-color toner images are respectively formed, an intermediate transfer belt onto which the mono-color toner images are respectively transferred to form a full-color toner image, and a transfer member for transferring the full-color toner image onto a copy sheet. The intermediate transfer belt includes timing marks printed thereon which are detected by a sensor to generate an image forming start signal for each of the first mono-color toner image forming processes. The start signal is generated by a controller only when cleaning of the intermediate transfer belt has completed and the cleaning blade has left therefrom. A timer may be used to delay the starting of the first mono-color image forming process until the transfer belt returns to a normal operating speed after the cleaning blade is removed from the transfer belt.

Registration control for an image forming apparatus having an

In a paper conveyer of an image forming apparatus, a transfer operation is performed by a transfer roller and an unfixed image in the transfer operation is carried onto the lower side of a transfer paper sheet. The transfer paper sheet is conveyed to a fixing device constructed by a fixing roller and a pressurizing roller. A hardness of the fixing roller is smaller than that of the pressurizing roller, while a nipping portion of the fixing and pressurizing rollers is formed in a concave shape. The fixing and pressurizing rollers are arranged such that a nipping inlet port point of the fixing and pressurizing rollers is located in the vicinity of a line of a conveying locus of a thin transfer paper sheet. A paper guide plate guides the transfer paper sheet to the nipping inlet port. In this construction, a transferred paper sheet is conveyed such that this transferred paper sheet is reliably fed into the nipping portion of the fixing device, and it is possible to prevent an image rub, wrinkles, a jam, etc. from being caused.

Paper conveyer of image forming apparatus which conveys paper to a

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Yokohama, Japan

Shingo Katou