Abstract A device for thermofusing an electroscopic toner image to the surface of a support by moving the support through a passageway formed by a pair of platens, at least one of which is heated. The heated platen is connected to an air supply, the air being discharged under pressure through a slot in the heated platen and directed toward the image-bearing surface. The air is heated as it is discharged and attains a temperature sufficient to fuse the toner image. The air pressure is sufficient to hold the support in a spaced relation with respect to the heated platen. In another embodiment, a vacuum platen is arranged adjacent the other surface of the support, the applied vacuum or suction drawing the thin layer of air on the image-bearing surface through the support to increase the efficiency of the device by utilizing the heated air more effectively.
A device for fusing an electroscopic toner image to the surface of a support bearing said toner image, comprising: two platens having spaced, opposed surfaces, at least one of said platens having a central chamber and being heated and provided with an elongated slot interconnecting said chamber to the heated surface thereof facing the image-bearing surface; means for moving said support between said opposed surfaces in a direction transverse of said slot with said image-bearing surface facing the heated surface of said one platen; means operatively associated with said heated platen for directing a flow of air under pressure into said chamber for discharge through said slot into the space between said opposed surfaces and at said image-bearing surface to maintain the latter in spaced relation to the heated surface of said one platen; said flow of air between said opposed surfaces transferring sufficient heat from the heated surface of said one platen to said image-bearing surface to fuse said toner image to said support.
Claim 2
Independent Claim
165 words
A device for fusing an electroscopic toner image to the surface of a support bearing said toner image, comprising: two platens having spaced, opposed surfaces, at least one of said platens having a central chamber and being heated and provided with an elongated slot interconnecting said chamber to the heated surface thereof facing the image-bearing surface; means for moving said support between said opposed surfaces in a direction transverse of said slot with said image-bearing surface facing the heated surface of said one platen; means operatively associated with said heated platen for directing a flow of air under pressure into said chamber for discharge through said slot into the space between said opposed surfaces and at said image-bearing surface to maintain the latter in spaced relation to the heated surface of said one platen; said flow of air between said opposed surfaces transferring sufficient heat from the heated surface of said one platen to said image-bearing surface to fuse said toner image to said support.
Claim 3
Dependent Claim
35 words
The fusing device in accordance with claim 1 wherein said heated platen is provided with one or more heating elements on each side of said chamber and adjacent the facing surface of said heated platen.
Claim 4
Dependent Claim
45 words
The fusing device in accordance with claim 1 wherein the other of said platens comprises a hollow, rotatable drum having a perforated peripheral surface for engaging the other surface of said support at least along a line generally opposite and aligned with said elongated slot.
Claim 5
Dependent Claim
30 words
The fusing device in accordance with claim 3 including vacuum means connected to said drum for maintaining the other surface of said support against the peripheral surface of said drum.
Claim 6
Dependent Claim
33 words
The fusing device in accordance with claim 1 wherein the space between the image-bearing surface of said support and the facing surface of said heated platen is from 0.005 to about 0.020 inches.
Claim 7
Dependent Claim
45 words
The fusing device in accordance with claim 4 wherein said vacuum means draws the thin layer of air on said image-bearing surface through said support, thereby rendering more effective the heat transfer from said heated platen to said image-bearing surface by said flow of air.