Heat-fusing apparatus in electrostatic copier

Claim 1

A copying apparatus of the type in which images are heatfused in an image-fixing station, said apparatus including duct means from which a blast of heated air is ejecTed into said image-fixing station, a source of electrical voltage, electrical heater means in said duct connectable to said source of electrical voltage for heating the blast of air ejected from said duct, thermostat means disposed in said image-fixing station and connected to said heater means and said source of electrical voltage for normally maintaining the temperature of said air blast at a temperature lower than the heat-fusion temperature of the copying paper employed in said apparatus but substantially higher than ambient temperature, and control circuit means responsive to the initiation of a copying operation for temporarily bypassing said thermostat to provide increased voltage to said heater means in response to the initiation of a copying cycle to cause the air blast from said duct to be at a temperature sufficiently high for heat-fusing an image on copy paper subsequently fed to said image-fixing station in response to the initiation of the printing cycle so that the temperature of the blast is at a sufficiently high level upon arrival of said copy paper at the image-fixing station to fuse the image on said copy paper.