Ricoh Company, Ltd.

Atsushi Arai

Masahiko Sato

Hiroshi Yokoyama

Hiroshi Kawano

Jun Okamoto

Yutaka Fukuchi

Toshiaki Higaya

Hirobumi Yoshino

Mitsuo Shibusawa

Tsutomu Yamakami

A fixing apparatus for fixing an image on a record sheet comprises a fixing roller in which a heater is disposed, a pressing roller urged against the fixing roller, heat pipes extending in either one of the fixing and pressing rollers in a longitudinal direction thereof, and a temperature detection / control device for detecting to control a temperature of the fixing roller. In a typical embodiment, the heat pipes are disposed in the fixing roller to extend both through an imaging portion, through which a record sheet passes, and through a non-imaging portion, through which no record sheet passes and the temperature detection / control device has a temperature detection device for detecting a temperature of the fixing roller in contact with the non-imaging portion. The temperature detection / control device is provided with a temperature regulating device for interrupting electricity to the heater when the fixing roller exceeds a predetermined temperature. In another embodiment, at least one of heat pipes is provided in the fixing roller in parallel with an axis of the fixing roller, and a core of the fixing roller is produced by extrusion.

Fixing apparatus

A method of controlling the surface temperature of a heat roller included in a fixing device and having a heater therein by sensing it by a thermistor. The thermistor is held in contact with the heat roller during warm-up operation and in a standby condition or spaced apart from the heat roller while a copying operation is under way. The heater is on/off controlled on the basis of a temperature measured when the thermistor is spaced apart from the heat roller. The method corrects this temperature by comparing temperatures measured in the contact and non-contact positions of the thermistor. In such a correction mode, if the difference between the two measured temperatures does not lie in a predetermined range, the method stops energizing the heater determining that an error has occurred.

Temperature control method for a fixing device

A copying paper processing apparatus comprises a sorter, a stapling device for stapling sheets of copying paper sorted by the sorter, and a device for automatically selecting and setting a sort mode when a staple mode is selected and set. The processing apparatus may comprise a switch for selecting the stapling operation, and a device for automatically selecting and setting a staple mode when the staple selecting switch is turned on and a sort mode is selectively set. The processing apparatus may comprise a device for transmitting a signal indicating that there is no staple needle when the number of staple needles left in the stapling device is a predetermined number greater than the total number of bins of the sorter. The processing apparatus may comprise a device for inhibiting the operation of the stapling device when one of sensors respectively disposed in a paper-receiving base of the stapling device and a sorter bin of the sorter detects that there is no paper.

Copying paper processing apparatus

A fixing apparatus installed in an image forming apparatus and having a pair of rollers engaged with each other for fusing and fixing toner images to a paper. Pivotable sheet separator pawls are resiliently engageable at their free ends with the periphery of one of the said rollers for separating from the periphery of the roller a leading end portion of the paper coming out of a nipping section of the rollers with the fixed toner images. The sheet separator pawls moves in parallel with the direction of axes of said rollers while said rollers stop.

Fixing apparatus having sheet separator pawls for image forming apparatus

A method of controlling a fixing unit which is installed in an electrophotographic copier, facsimile apparatus or like image forming apparatus and includes a fixing roller and a pressing roller. A secure fixing temperature of the fixing unit is selectively set to at least two different temperatures.

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Ichikawa, Japan

Atsushi Arai