Electric heaters

Claim 2

A quick-response electric heater, adapted for use in a xerographic system, comprising: a support frame, electric resistance means comprising a plurality of reaches extending between terminals carried by a first pair of opposed parts of said frame, the resistance means being in the form of a bare resistance metal of small cross-sectional area and therefore fragile in nature, and a plurality of supports extending in spaced relation between a second pair of opposed parts of said frame, and crosswise of said reaches, each support comprising a pair of superimposed insulating rods of substantially circular cross section having opposite ends connected to respective ones of said second pair of opposed parts of said frame, each pair of rods engaging opposed surfaces of said reaches at substantially the same point to sandwich the latter therebetween, thereby to support said reaches against sagging at a plurality of places spaced longitudinally thereof.

Claim 3

The construction of claim 1 wherein said resistance means is in the form of a bare metal resistor ribbon, and wherein each pair of rods engages opposed flat surfaces of said ribbon.

Claim 4

The construction of claim 2 wherein each ribbon reach is corrugated, and wherein each pair of rods cooperates with corrugations of said ribbons to restrict thermal expansion of the ribbon in said reaches between adjoining pair of said supports.

Claim 5

The construction of claim 1 wherein each of said insulating rods is in the form of a small diameter metal rod having its opposite ends connected to respective ones of said second pair of opposed frame parts, and ceramic tubes threaded onto said metal rods and engageable with opposed surfaces of said resistance means reaches.

Claim 6

The construction according to claim 1 wherein said frame support is formed of sheet metal and said first pair of opposed frame parts are opposed sheet metal walls, each having a plurality of slots therein, with apertured ceramic bushings seated within respectives slots, said terminals being of good electrically conductive metal, each having one portion extending through an aperture in a respective bushing and outwardly of the space defined by said frame for electrical power connection, each terminal having a second portion extending from a respective bushing and inwardly of the space defined by said frame support and electrically connected to the adjoining end of a reach of said resistance means.

Claim 7

An electric heater for use in a xerographic system and the like, comprising a metal frame having a rectangular opening defined by opposed pairs of frame legs, one pair of opposed frame legs having slots for receiving insulating blocks, the latter being locked in respective slots by deformation of walls margining such slots, a terminal for each block, having a tail portion extending through an opening in the block and a head portion extending into the frame opening, a plurality of reaches of metal resistance ribbon, each reach spanning the space bEtween head portions of corresponding terminals, said ribbon being in the order of about 0.001 inch thick for rapid heating and being transversely corrugated, and a plurality of support members extending crosswise of said ribbon reaches to support the same at places spaced longitudinally of their span, each support member comprising a pair of supports, one above and the other below said ribbon reaches, and each support comprising a metal rod of small diameter having its ends connected to the other pair of opposed frame legs and ceramic bushings of small diameter on said metal rods and engageable with opposite sides of the ribbon in said reaches, said ceramic bushings interengaging with the corrugations of said ribbon reaches to restrict thermal expansion of said ribbon in said reaches between adjoining pair of said supports.

Claim 8

An electric heater for use in a xerographic system and the like, comprising a metal frame having a rectangular opening defined by opposed pairs of frame legs, one pair of opposed frame legs having slots for receiving insulating blocks, the latter being locked in respective slots by deformation of walls margining such slots, a terminal for each block, having a tail portion extending through an opening in the block and a head portion extending into the frame opening, a plurality of reaches of metal resistance ribbon, each reach spanning the space bEtween head portions of corresponding terminals, said ribbon being in the order of about 0.001 inch thick for rapid heating and being transversely corrugated, and a plurality of support members extending crosswise of said ribbon reaches to support the same at places spaced longitudinally of their span, each support member comprising a pair of supports, one above and the other below said ribbon reaches, and each support comprising a metal rod of small diameter having its ends connected to the other pair of opposed frame legs and ceramic bushings of small diameter on said metal rods and engageable with opposite sides of the ribbon in said reaches, said ceramic bushings interengaging with the corrugations of said ribbon reaches to restrict thermal expansion of said ribbon in said reaches between adjoining pair of said supports.