Fusing apparatus

Abstract

An apparatus in which a powder pattern deposited on a support material is permanently affixed thereto. The support material is heated during the movement thereof into thermal communication with a radiant energy output. In this manner, the powder pattern is coalesced and fixed permanently to the support material. .[.The foregoing abstract is neither intended to define the invention disclosed in the specification, nor is it intended to be limiting as to the scope of the invention in any way..].

What is claimed is: .[.1. An electrophotographic printing machine of the type having a powder pattern formed on a sheet of support material, wherein the improvement includes: 
     
        pattern to the sheet of support material..]. 2. .[.A printing machine as recited in claim 1, further including:.]. .Iadd.An electrophotographic printing machine of the type having a powder pattern formed on a sheet of support material, wherein the improvement includes: means for transporting the sheet of support material with the powder image deposited on one surface thereof along a path of movement, said transport means being arranged to be in substantial contact with the other surface of the sheet of support material;   means for heating said transport means;   a radiant energy source having at least one heat strip arranged to be in thermal communication with the sheet of support material for supplying the energy output thereof onto the sheet of support material being moved with the powder pattern thereon by said transport means along the path of movement coalescing and affixing substantially permanently the powder pattern to the sheet of support material; .Iaddend.   first control means arranged to actuate said heating means in response to the printing machine being energized for rapidly heating and regulating said transport means at about a standby temperature; and   second control means arranged to actuate said radiant energy source, in response to the printing machine being energized, for rapidly heating said transport means to about the standby temperature; and deactuating said radiant energy source at about the standby temperature, said second control means, responsive to the sheet of support material being positioned on said transport means, for regulating said radiant energy source about a predetermined temperature at a lower power level and below   
     
     
        the predetermined temperature at a higher power level. 3. A printing machine as recited in claim 2, wherein said second control means includes: means for sensing the temperature in the region of said radiant energy source and generating an electrical output signal corresponding thereto;   means for developing a reference corresponding to the predetermined temperature;   means for comparing the electrical output signal with the reference to generate an electrical error signal indicative of the difference therebetween for regulating the power output from said radiant energy source; and   means for switching said radiant energy source to the lower power level from the higher power level in response to the electrical error signal from said comparing means indicating said sensing means being above the   
     
     
        predetermined temperature. 4. A printing machine as recited in claim 2, wherein said first control means includes: means for sensing the temperature in the region of said transport means and generating an electrical output signal corresponding thereto;   means for developing a reference corresponding to the standby temperature; and   means for comparing the reference with the electrical output signal and generating an electrical error signal indicative of the difference   
     
     
        therebetween for regulating the power from said heating means. 5. A printing machine as recited in .[.1.]. .Iadd.2 .Iaddend.wherein said transport means includes: a lower housing member defining an interior open ended chamber;   a frame member mounted removably in the chamber of said lower housing member;   a plurality of rollers mounted rotatably on said frame member, said rollers being positioned spaced from one another and having the axes of rotation thereof substantially parallel to one another;   an endless belt member having a plurality of apertures therein, said belt member being entrained about said rollers; and   means for removing air from the chamber of said lower housing to secure releasably the sheet of support material to the exterior surface of said   
     
     
        belt member. 6. A printing machine as recited in claim 5, wherein said endless belt member preferably is made from a high temperature elastomer. 
     
     
         . A printing machine as recited in claim 5, wherein said heating means includes: a plate member having a plurality of apertures therein, said plate member being mounted in the open end of the chamber of said lower housing interposed between said rollers and substantially contacting the interior surface of said belt member; and   at least one resistance heating element disposed in the chamber of said lower housing member, said heating element being positioned in the path of movement of the air being removed from the chamber heating the air which   
     
     
        heats said belt member. 8. .[.A printing machine as recited in claim 5, wherein said radiant energy source includes:.]. .Iadd.An electrophotographic printing machine of the type having a powder pattern formed on a sheet of support material, wherein the improvement includes: a lower housing member defining an interior open-ended chamber;   a frame member mounted removably in the chamber of said lower housing member;   a plurality of rollers mounted rotatably on said frame member, said rollers being positioned spaced from one another and having the axes of rotation thereof substantially parallel to one another;   an endless belt member having a plurality of apertures therein, said belt member being entrained about said rollers;   means for removing air from the chamber of said lower housing to secure releasably the sheet of support material to the exterior surface of said belt member; .Iaddend.   a cover member mounted on said lower housing member and defining with said lower housing member a passage way enabling said endless belt member to move support material therethrough;   at least one radiant heat strip secured to said cover member, said heat strip being configured to furnish substantially uniform radiation across the surface of the sheet of support material; and   reflecting means interposed between said cover member and said radiant strip directing the energy output therefrom onto the support material to   
     
     
        coalesce and permanently affix the powder pattern thereto. 9. A printing machine as recited in claim 8, wherein said heat strip is preferably made 
     
     
        from a helically wound ribbon of low thermal mass. 10. A printing machine as recited in claim 9, further including a pair of opposed spaced support members having said helical ribbon entrained thereabout, one of said support members being mounted substantially fixedly on said cover member and the other of said support members being mounted resiliently on said cover member to compensate for thermal expansion of said helical ribbon. 
     
     
          . A printing machine as recited in claim 8 wherein said heat strip is preferably made from high temperature nickel chromium alloy.