Fuser control apparatus

Claim 2

Apparatus for sensing the velocity of a sheet of final support material during the heat fusing of a xerographic image thereto including: transport means for moving the sheet past a source of heat energy at a predetermined velocity whereby the xerographic image on said sheet is fused and the sheet remains undamaged; an encoder disk positioned at the sheet entrance to the fusing zone and being arranged to be rotated by contacting a sheet passing therethrough; optical means operatively associated with said encoder disk for generating a signal indicative of the sensed sheet velocity; means for comparing the sensed sheet velocity to said predetermined velocity; and means responsive to said last mentioned means to inactivate said source of energy when said sensed sheet velocity falls below said predetermined velocity.

Claim 3

The apparatus of claim 1 wherein said means to compare the sheet rate to said predetermined rate consists of electrical means for differentiating the encoded signal to obtain a true sheet velocity output, and clock means for comparing the true sheet velocity signal with a predetermined output velocity signal.

Claim 4

The apparatus of claim 2 wherein said encoder disk has a serrated outer periphery and wherein said disk has a series of equally distant spaced apertures therein and a series of congruent opaque areas between said apertures, and wherein said optical means comprises cooperating optical elements positioned on either side of said disk so that opaque disk areas interrupt the optical communication between the elements to generate a periodic signal.

Claim 5

Apparatus for sensing the velocity of a sheet of final support material during the heat fusing of a xerographic image thereto including: transport means for moving the sheet past a source of heat energy at a predetermined velocity whereby the xerographic image on said sheet is fused and the sheet remains undamaged; means for sensing and encoding the velocity of the sheet as it moves through the fusing zone; electrical means for differentiating the encoded signal to obtain a true sheet velocity signal; clock means for comparing the true sheet velocity signal with a predetermined velocity signal; and means responsive to said last mentioned means to inactivate said souce of energy when the true sheet velocity signal fals below said predetermined velocity signal.

Claim 6

Apparatus for sensing the velocity of a sheet of final support material during the heat fusing of a xerographic image thereto including: transport means for moving the sheet past a source of heat energy at a predetermined velocity whereby the xerographic image on said sheet is fused and the sheet remains undamaged; means for sensing and encoding the velocity of the sheet as it moves through the fusing zone; electrical means for differentiating the encoded signal to obtain a true sheet velocity signal; clock means for comparing the true sheet velocity signal with a predetermined velocity signal; and means responsive to said last mentioned means to inactivate said souce of energy when the true sheet velocity signal fals below said predetermined velocity signal.

Claim 7

The apparatus of claim 4 wherein said encoder disk has a serrated outer periphery, and wherein said disk has a series of equally distant spaced apertures therein and a series of congruent opaque areas between said apertures, and wherein said optical means comprises cooperating optical elements positioned on either side of said disk so that opaque disk areas interrupt the optical communication between the elements to generate a periodic signal.

Claim 8

Apparatus for preventing the destruction of a sheet of final support material during the heat fusing of a xerographic image thereto including: a radiant source of energy arranged to concentrate its output within a fusing zone; transport means for moving the image bearing sheet of final support material through said fusing zone in thermal communication with said energy source at a predetermined velocity sufficient to fix the images thereon and being insufficient to damage such support sheet; an encoder disk positioned at the sheet entrance to the fusing zone and being arranged to be rotated by contacting a sheet passing therethrough; optical means operatively associated with said encoder disk for generating a signal indicative of the sensed sheet velocity; comparator means for comparing the sensed sheet velocity to said predetermined velocity; and means responsive to said comparator means to inactivate the radiant source of energy when the true sheet velocity falls below said predetermined velocity.

Claim 9

Apparatus for preventing the destruction of a sheet of final support material during the heat fusing of a xerographic image thereto including: a radiant source of energy arranged to concentrate its output within a fusing zone; transport means for moving the image bearing sheet of final support material through said fusing zone in thermal communication with said energy source at a predetermined velocity sufficient to fix the images thereon and being insufficient to damage such support sheet; an encoder disk positioned at the sheet entrance to the fusing zone and being arranged to be rotated by contacting a sheet passing therethrough; optical means operatively associated with said encoder disk for generating a signal indicative of the sensed sheet velocity; comparator means for comparing the sensed sheet velocity to said predetermined velocity; and means responsive to said comparator means to inactivate the radiant source of energy when the true sheet velocity falls below said predetermined velocity.

Claim 10

The apparatus of claim 6 wherein said encoder disk has a serrated outer periphery, and wherein said disk has a series of equally distant spaced apertures therein and a series of congruent opaque areas between said apertures, and wherein said optical means comprises cooperating optical elements positioned on either side of said disk so that opaque disk areas interrupt the optical communication between the elements to generate a periodic signal.

Claim 11

The apparatus of claim 7 wherein said inactivation means is further operable to inactivate said transport means.