Mita Industrial Co., Ltd.

Atsushi Kanou

Arihiro Tsunoda

Syuji Yamada

Toshinobu Katafuchi

Toshiyuki Osaka

Naoki Mizutani

Hiroyoshi Omuras

A transfer unit of an image forming apparatus includes a transfer device, a pressing member, and a regulative member. The transfer device is provided adjacent to a photoconductor of the image forming apparatus and is separable from the photoconductor under its own weight. The pressing member presses the transfer device against the photoconductor. The regulative member regulates the distance by which transfer device is separated from the photoconductor when the pressing member disengages the transfer device therefrom. In this transfer unit, if a printing sheet is large, the pressing member disengages the transfer device after a given transfer operation. As a result, the transfer device separates from the photoconductor under its own weight, with the distance separating the transfer device from the photoconductor being regulated by the regulative member. Then, the transfer device idles in the separated state, wherein preparation for a subsequent transfer operation is made. In this manner, the transfer device is idled simply by regulating the movement of the transfer device through means of the regulative member. Consequently, little distortion occurs to the transfer unit support frames, and deterioration of the quality of the transferred images is thus checked.

Transfer unit of an image forming apparatus

A nipping device is provided in a transfer unit having a fixed support and rotating element rotatably supported by the fixed support. The nipping device retains a printing sheet against the circumferential surface of the rotating element, and separates the printing sheet from the transfer unit. The nipping device includes a nipper, a pivoting lever device and a drive device. The nipper is disposed pivotally on the circumferential surface of the rotating element, and retains the feed-leading edge of the printing sheet. The levers of the pivoting lever device are disposed within the rotating element, pivotal on an axes intersecting the circumferential surface of the transfer unit, and functions therein to open and close the nipper by which the printing sheet is nipped against and separated from the transfer unit. The drive device is disposed in the fixed support, and functions to turn the pivoting levers. Due to the structure of this device, it is possible to impel the pivoting levers in a uniform direction by the use of tension springs, and furthermore the setting of the impelling force of the springs to the minimum necessary, is facilitated, such that the load applied to the driving system of the transfer unit can be reduced.

Nipping device of a transfer unit

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Amagasaki, Japan

Atsushi Kanou