An electro-photographic printing device has a development location where toner is transferred onto a drum in proportion to the amount of light charges on the drum and a transfer location where toner is transferred from the drum to a sheet of paper. A heater unit for fixing the toner by heating it to a predetermined temperature has a heater and a blower for heat removal. Responsive to a call for printing, data to be printed are stored in a memory. The heater is energized until a set temperature is obtained. Printing is initiated as soon as the set temperature is obtained. The blower is stopped after heating has been discontinued, after printing has been completed, until there is a new call.