Fuser control circuit for copying apparatus

Claim 2

In an apparatus for producing copies of documents having a fuser for fixing images produced on the copies together with a heater for heating the fuser, the combination of: switching means to control power to said fuser heater adapted when in a first switching state to provide power to said heater and when in a second switching state to interrupt power to said heater; and control means for operating said switching means including first capacitance means adapted on a predetermined charge to switch said switching means to said second state whereby power to said heater is interrupted, means to charge said first capacitance means in proportion to line voltages across said heater, second capacitance means adapted on a predetermined charge to switch said switching means to said first state and provide power to said heater, and means for charging said second capacitance means in response to switching of said switching means to said second state.

Claim 3

In a reproduction apparatus for producing copies of original documents, said apparatus including a fuser for permanently fixing the images produced and a heater for heating said fuser, the combination of: switching means in the power circuit to said heater switchable on a predetermined control signal to a blocking condition whereby power to said heater is interrupted; control switch means adapted in a first switch condition to provide said control signal and in a second switch condition to terminate said control signal; and circuit means for operating said control switch means including a first control capacitor, means to charge said first capacitor in proportion to the power supplied to said heater, said circuit means being adapted on a predetermined first capacitor charge to trigger said control switch means to said first switch condition whereby said switching means is switched to a blocking condition and power to said heater is interrupted, and a second control capacitor chargeable upon switching of said control switch means to said first switch condition, said circuit means being adapted on a predetermined second capacitor charge to trigger said control switch means to said second switch condition whereby said switching means is switched to a conducting condition and power is provided to said heater.

Claim 4

In a reproduction apparatus for producing copies of original documents, said apparatus including a fuser for permanently fixing the images produced and a heater for heating said fuser, the combination of: switching means in the power circuit to said heater switchable on a predetermined control signal to a blocking condition whereby power to said heater is interrupted; control switch means adapted in a first switch condition to provide said control signal and in a second switch condition to terminate said control signal; and circuit means for operating said control switch means including a first control capacitor, means to charge said first capacitor in proportion to the power supplied to said heater, said circuit means being adapted on a predetermined first capacitor charge to trigger said control switch means to said first switch condition whereby said switching means is switched to a blocking condition and power to said heater is interrupted, and a second control capacitor chargeable upon switching of said control switch means to said first switch condition, said circuit means being adapted on a predetermined second capacitor charge to trigger said control switch means to said second switch condition whereby said switching means is switched to a conducting condition and power is provided to said heater.

Claim 5

A power controller for the fuser of a copying machine adapted to maintain a predetermined power input to the fuser despite variations in line voltage, comprising, in combination: means monitoring poweR input to said fuser adapted when said predetermined power level is reached to cut off power to said fuser; and means adapted following a preset timed interval to restore power to said fuser.

Claim 6

A power controller for the fuser of a copying machine adapted to maintain a predetermined power input to the fuser despite variations in line voltage, comprising, in combination: means monitoring poweR input to said fuser adapted when said predetermined power level is reached to cut off power to said fuser; and means adapted following a preset timed interval to restore power to said fuser.

Claim 7

A power controller for the fuser of a copying machine adapted to maintain a predetermined power input to the fuser despite variations in line voltage, comprising, in combination: means to cut off said fuser from the power source whenever power input to said fuser exceeds a predetermined level; and means to prevent restoration of power to said fuser for a preset interval.

Claim 8

A power controller for the fuser of a copying machine adapted to maintain a predetermined power input to the fuser despite variations in line voltage, comprising, in combination: means to cut off said fuser from the power source whenever power input to said fuser exceeds a predetermined level; and means to prevent restoration of power to said fuser for a preset interval.

Claim 9

A power controller to protect the fuser of a copying machine from excessive line voltage, comprising: signal generating means for monitoring power levels across said fuser adapted on a predetermined power level to generate a preset control signal; means responsive to said control signal to interrupt said line voltage and terminate power to said fuser; and timing means adapted following a timed interval to restore said line voltage.

Claim 10

A power controller to protect the fuser of a copying machine from excessive line voltage, comprising: signal generating means for monitoring power levels across said fuser adapted on a predetermined power level to generate a preset control signal; means responsive to said control signal to interrupt said line voltage and terminate power to said fuser; and timing means adapted following a timed interval to restore said line voltage.

Claim 11

In an apparatus for producing copies of documents having a fuser for fixing images produced on the copies together with a heater for heating the fuser, the combination of: switching means to control power to said fuser heater adapted when in a first switching state to provide power to said heater and when in a second switching state to interrupt power to said heater; and control means for operating said switching means including means responding to power input to said heater adapted on a preset power input to switch said switching means to said second state whereby power to said heater is interrupted; and means for switching said switch means to said first state following a predetermined interval whereby to restore power to said fuser.

Claim 12

In an apparatus for producing copies of documents having a fuser for fixing images produced on the copies together with a heater for heating the fuser, the combination of: switching means to control power to said fuser heater adapted when in a first switching state to provide power to said heater and when in a second switching state to interrupt power to said heater; and control means for operating said switching means including means responding to power input to said heater adapted on a preset power input to switch said switching means to said second state whereby power to said heater is interrupted; and means for switching said switch means to said first state following a predetermined interval whereby to restore power to said fuser.