Xerographic fusing apparatus

Claim 1

XEROGRAPHIC FUSING APPARATUS FOR FUSING A XEROGRAPHIC POWDER IMAGE FUSIBLE AT A TEMPERATURE BELOW THE CHARRING TEMPERATURE OF PAPER ON A PAPER SHEET COMPRISING A SUPPORTING FRAME AND SUPPORT MEMBERS MOUNTED THERON, A ROTATABLE DRUM ON THE SUPPORT MEMBERS AND MEANS FOR ROTATING THE DRUM, A PLURALITY OF CORONA DISCHARGE WIRES ARRANGED IN STATIONARY POSITION ALONG ONE SEGMENT AROUND THE DRUM AND SPACED FROM THE SURFACE OF THE DRUM, MEANS TO FEED A PAPER SHEET BETWEEN THE CORONA DISCHARGE WIRES AND THE DRUM THE PAPER BEING POSITIONED TO RECEIVE A DEPOSIT OF ION DISCHARGE IN ITS OUTER SURFACE WHILE IN CONTACT WITH THE DRUM THERBY ELECTROSTATICALLY SECURING THE PAPER AGAINST THE DRUM AND IN CLOSE CONTACT THERWITH, AND HEATING MEMBERS CONTAINED WITHIN THE DRUM TO HEAT THE DRUM SURFACE, WHEREBY THE HOT ROTATING DRUM FILLS THE DUAL ROLE OF DIRVE MEMBER FOR THE SHEET MATERIAL AND THE FUSING ZONE MEMBER AND HEATS THE FUSIBLE POWDER TO ITS FUSING POINT BY CONDUCTION THROUGH THE SHEET MATERIAL, THE CORONA WIRES BEING ARRANGED IN TWO GROUPS, THE FIRST GROUP BEING CLOSLY IN POSITION ADJACENT TO THE POINT OF FIRST CONTACT BETWEN THE PAPER SHEET AND THE DRUM, AND THE SECOND GROUP BEING SPACED SUBSTANTIALLY MORE WIDLEY APART.