Multiple sheet detecting apparatus
AssigneeEastman Kodak Company
InventorsPhillip W. Pearce, Robert J. Hutchison
Life of this patent
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Abstract
A multiple sheet detecting apparatus is disclosed which includes an ultrasonic transducer responsive to a time varying electrical signal to produce a time varying ultrasonic signal which impinges upon sheet(s) at a position along a predetermined path. A second ultrasonic transducer receives a portion of the ultrasonic wave which passes through such impinged upon sheet(s) for producing a second time varying signal. Comparison means are then provided which compare the phase relationship between the time varying electrical signals and produce an indication when such phase relationship indicates a multiple sheet feed condition has occurred.
Claims8
Apparatus for detecting the presence of multiple sheets moving along a predetermined path, comprising:
- a. means for producing a first time varying electrical signal;
- b. first transducer means disposed on one side of the path and responsive to said first time varying signal for producing a time varying ultrasonic signal which impinges upon sheet(s) at a first position along the path;
- c. second transducer means disposed on the opposite side of the sheet path and aligned with said first transducer means to receive at least a portion of the ultrasonic wave which impinged upon said sheet(s) for producing a second time varying electrical signal;
- and
- d. phase comparison means responsive to said first and second time varying electrical signals for comparing their phase relationship and producing an output signal when such phase relationship indicates a multiple sheet feed condition has occurred.
Apparatus for detecting the presence of multiple sheets moving along a predetermined path, comprising:
- a. means for producing a first time varying electrical signal;
- b. first transducer means disposed on one side of the path and responsive to said first time varying signal for producing a time varying ultrasonic signal which impinges upon sheet(s) at a first position along the path;
- c. second transducer means disposed on the opposite side of the sheet path and aligned with said first transducer means to receive at least a portion of the ultrasonic wave which impinged upon said sheet(s) for producing a second time varying electrical signal;
- d. means responsive to said first and second time varying signals for producing a third electrical signal having a parameter which is a function of the difference between the phases of such first and second signals;
- e. means for producing a reference signal having a parameter which defines a range of parameters for the parameter of said third signal so that the third signal parameter will be within such range when a multiple sheet condition has occurred;
- and
- f. comparison means for comparing such third electrical signal and reference signal parameters for producing an output indicating that a multiple sheet condition has occurred when the third parameter is within such reference signal parameter range.
Method for detecting a multiple sheet feed condition comprising:
- a. producing a time varying ultrasonic signal which impinges upon sheet(s) at a first position along a predetermined sheet feeding path;
- b. receiving a portion of the ultrasonic wave which impinged upon such sheet(s) and, in response thereto, producing a first time varying electrical signal;
- and
- c. providing an output when the phase of such first time varying electrical signal indicates a multiple sheet feed condition has occurred.
Method for detecting a multiple sheet feed condition comprising:
- a. producing a first time varying electrical signal at a predetermined frequency;
- b. producing a time varying ultrasonic signal at such predetermined frequency which impinges sheet(s) at a position along a predetermined path;
- c. receiving a portion of said ultrasonic signal which impinged upon said sheet(s) and, in response thereto, producing a second time varying electrical signal;
- and
- d. comparing such first and second electrical signals and producing an output when the phase difference between said signals indicates that a multiple sheet feed condition has occurred.
Method for determining the presence or absence of a sheet at a predetermined position comprising:
- a. directing a time varying ultrasonic signal to said predetermined position;
- b. receiving a portion of the ultrasonic signal coming from said predetermined position;
- c. comparing the phase of the directed and received ultrasonic signals;
- and
- d. producing an indication of the presence or absence of a sheet at said predetermined position in accordance with the differences in phase of said directed and received ultrasonic signals.
Method for determining whether or not a sheet is disposed at a predetermined position along a path comprising:
- a. producing a first time varying electrical signal at a predetermined frequency;
- b. producing a time varying ultrasonic signal having a frequency and phase which corresponds to that of said first signal;
- c. directing said ultrasonic signal to impinge upon a sheet if it were disposed at said predetermined position;
- d. receiving at least a portion of the ultrasonic signal at said predetermined position and, in response thereto, producing a second time varying electrical signal having a frequency and phase corresponding to said received ultrasonic signal;
- and
- e. comparing the phase relationship between the first and second electrical signals and in response thereto producing a manifestation of whether or not a sheet is disposed at the predetermined position.
Dependencies are inferred from the claim text.