Abstract: 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.

Abstract: An automatic density control device in a copying machine combined with an automatic document feeder capable of feeding a document onto a document support table has a document density detector for detecting the density of a document placed on the document support table, a scanner means movable in a forward direction for exposure to the image of the document on the document support table and movable in a backward direction for enabling the document density detector means to read the density of the document on the document support table, a reference position detector for detecting when the scanner means reaches a reference position, and a controller for determining the density of the document from a document density signal from the document density detector means in a range prior to generation of a signal by the reference position detector means when the scanner means moves back to the reference position, for determining an amount of exposure or an image developing bias voltage based on the document density sign