Apparatus for adaptively checking document thickness

Claim 2

The combination comprising: a. first means for providing a first voltage; b. second means for providing a voltage range; said voltage range being a predetermined percentage of a second voltage; c. means coupled to said first means and said second means for comparing said voltage to said voltage range, said comparing means providing a signal in either a first or second state; and d. means coupled to said comparing means and responsive to the signal provided thereby for repetitively changing said voltage range provided by said second means when said comparing means provides said signal in said first state.

Claim 3

The combination as defined in claim 1 and further comprising: halt means for indicating when said first voltage is unacceptable, and means coupled to said comparing means for initializing said halt means when said comparing means is in said second state.

Claim 4

The combination as defined in claim 1 wherein said second voltage is a reference voltage and wherein said second means includes at least one voltage window which has a range of voltage comprising a predetermined percentage of said reference voltage.

Claim 5

The combination as defined in claim 3 wherein said window includes a resistive divider; and, said resistive divider providing a voltage corresponding to an extreme voltage.

Claim 6

The combination as defined in claim 1 wherein said second means includes a first voltage window and a second voltage window; said first window providing a voltage equal to an upper voltage reference; and said second window providing a voltagE equal to a lower voltage reference.

Claim 7

The combination as defined in claim 5 wherein said comparison means includes a first amplifier which contrasts said voltage of said first means to said voltage of said first window; a second amplifier which contrasts said voltage of said first means to said voltage of said second window; said first amplifier providing a signal in said first state when said voltage of said first means is less than said voltage of said first window; and said second amplifier providing a signal in said first state when said voltage of said first means is greater than said voltage of said second window.

Claim 8

The combination as defined in claim 1 wherein said second means includes a gating element, said signal in said first state from said comparing means enabling said gating element to transfer said first voltage to said second voltage, said voltage range of said second means being changed to a predetermined percentage of said first voltage.

Claim 9

The combination as defined in claim 1 and further including initializing means coupled to said comparing means and said means for changing for energizing said means for changing; and said initializing means including a bistable means having a first and second state.

Claim 10

The combination as defined in claim 8 and further including time delay means coupled to said first means for providing a predetermined delay period; said time delay means responsive to said voltage from said first means; and said time delay means providing a signal to said means for changing and to said means for initializing.

Claim 11

Document thickness checking apparatus comprising: reference voltage means for providing a reference voltage, source means for providing a voltage to be monitored, means responsive to said reference voltage for establishing a voltage range having the limits of an acceptable voltage being monitored, means responsive to said source means and said establishing means for comparing said voltage to said voltage range, and means responsive to said comparing means for transferring said voltage of said source means to said reference voltage means when said voltage of said source means is within said voltage range, whereby said voltage becomes the reference voltage and said establishing means effects a new voltage range.

Claim 12

Document thickness checking apparatus comprising: reference voltage means for providing a reference voltage, source means for providing a voltage to be monitored, means responsive to said reference voltage for establishing a voltage range having the limits of an acceptable voltage being monitored, means responsive to said source means and said establishing means for comparing said voltage to said voltage range, and means responsive to said comparing means for transferring said voltage of said source means to said reference voltage means when said voltage of said source means is within said voltage range, whereby said voltage becomes the reference voltage and said establishing means effects a new voltage range.

Claim 13

Apparatus as defined in claim 10 wherein said reference voltage is proportional to the thickness of a first document received by said apparatus and wherein said source voltage is proportional to the thickness of a second document received by said apparatus after the reception of said first document, whereby the voltage of said first means for providing is refreshed with a voltage corresponding to successively received documents.

Claim 14

Apparatus as defined in claim 11 wherein said means for changing is inhibited if said voltage proportional to the thickness of said second document is outside said voltage range.

Claim 15

Apparatus as defined in claim 11 wherein said reference voltage means includes a capacitor and wherein said capacitor is changed to said voltage proportional to said second document if said voltage proportional to the thickness of said second document is within said voltage range.

Claim 16

Adaptive document thickness checking apparatus comprising: a. a first voltage means for providing a voltage corresponding to the thickness of an unknown document, b. a second voltage means coupled to said first voltage means for providing a voltage corresponding to the thickness of a previously detected document, c. comparison means coupled to both said first and second voltage means for contrasting said voltage from said first voltage means to said voltage from said second voltage means, said comparison means providing a signal in either a first or second state, d. control means coupled to said comparison means and responsive to said signal in said first state from said comparison means, said contrOl means coupled to change said voltage of said second voltage means to the voltage of said first voltage means, and e. inhibiting means coupled to said comparison means and responsive to said signal in said second state from said comparison means, said inhibiting means arresting the operation of said apparatus.

Claim 17

Adaptive document thickness checking apparatus comprising: a. a first voltage means for providing a voltage corresponding to the thickness of an unknown document, b. a second voltage means coupled to said first voltage means for providing a voltage corresponding to the thickness of a previously detected document, c. comparison means coupled to both said first and second voltage means for contrasting said voltage from said first voltage means to said voltage from said second voltage means, said comparison means providing a signal in either a first or second state, d. control means coupled to said comparison means and responsive to said signal in said first state from said comparison means, said contrOl means coupled to change said voltage of said second voltage means to the voltage of said first voltage means, and e. inhibiting means coupled to said comparison means and responsive to said signal in said second state from said comparison means, said inhibiting means arresting the operation of said apparatus.

Claim 18

An apparatus as defined in claim 14 and further including time delay means coupled between said first voltage means and said control means for providing a predetermined period between the introduction of said voltage to said first voltage means and said signal from said comparison means, initializing means coupled to said comparison means for providing a signal to said comparison means, said initializing means inhibiting said comparison means.

Claim 19

An apparatus as defined in claim 15 wherein said second voltage means includes a memory element storing said voltage of said second voltage means, a first window including a first resistive divider, said first window providing a voltage equal to an upper limit reference voltage, a second window including a second resistive divider, said second window providing a voltage equal to a lower limit reference voltage, and said voltage of said memory element providing the basis for said upper and lower limit reference voltage.