Method and arrangement for preventing sheets from charring in copying machines

摘要

In an electro-photographic copier of the type wherein an image is formed on an image-carrying sheet and is thereafter fixed by subjecting the sheet at a fixing station to the influence of heat, a combination comprises a heating device at the fixing station for fixing an image on a sheet, and a conveyor device for moving the heating device relative to a sheet located in the fixing station at a predetermined speed sufficient to permit the heating device to fix the image on the sheet and also to prevent charring of the latter. A sheet-advancing device advances a sheet through the fixing station in direction opposite to the direction of movement of the conveyor device so as to increase the relative speed between the heating device and the advancing sheet. The movement of the heating device relative to the sheet prevents charring or burning of the sheet in the event that the sheet-advancing device malfunctions and advances a sheet at speeds lower than its normally rated speed, including zero speed, i.e., complete breakdown.