FUSER BASE PLATE TEMPERATURE CONTROLS
Original Publication Date: 1984-Feb-29
Included in the Prior Art Database: 2004-Apr-04
Xerox Disclosure Journal
Many electrostatographic reproducing machines employ a radiant fuser to fix the toner image to the copy paper support substrate. Typically, these radiant fusers include a heating element such as a lamp positioned above a base platen to soften the toner particles and fuse them into the copy sheet. Once the base plate has been heated to a temperature of about 230°F it is desirable to circulate air through the base plate in order to prevent its temperature from exceeding 230°F, thereby preventing scorching of the copy sheet. This is readily accomplished with the aid of a channel through the base plate and a blower blowing air therethrough. However, during the warm up time of the radiant fuser including the base plate, it is desirable to heat the base plate to the fusing temperature as quickly as possible. Accordingly, it is desirable to restrict the air flow through the channel in the base plate during this period of time. The figure illustrates a technique in which this may be done with the use of a bi-layered member that bends with temperature much in the way that a bi-metallic strip does. Thus-during the start up time when the base plate is cold the bi-layered material is within the channel in the base plate restricting the air flow so that it reaches the fusing temperature at an earlier time. Once heated to the fusing temperature, the bi-layered member moves out of the air path and air flow can continue to then cool the base plate. The bi-layered material is formed typically from a material having a high temperature coefficient of expansion such as, for example, a polymer and a material having a low temperature coefficient of expansion. This may be accomplished by laying one material over a cylinder applying an adhesive and applying the other material, thus gluing the two materials together. The preformed materials are then cut and inserted into the base plate blocking air flow when the base plate is cold and allowing air to flow when it is hot.