To exclude a range in which accurate position cannot be decided due to slip and a range in which a detection level of an optical sensor is unstable, in detecting double feed at the same position in sheets of paper.
A conveyance pulse of a frequency proportional to the rotation speed of a drive motor for paper feeding and for driving a conveyance roller pair after the paper has passed an optical sensor 6, is generated. A light receiving level of the optical sensor from the front end to the rear end of the paper 1 is sequentially recorded in each memory element of a memory element row, for each pulse. A double feed detection position is determined from among rank positions between a rank that decreases from the front end by the number obtained by adding a margin to the number of pulses including slip from the front end of the paper passing the optical sensor to reaching the conveyance roller pair, and a rank that goes back from the rear end by the number obtained by adding a margin to the number of pulses from the rear end of the paper departing from a paper feed means to reaching the optical sensor.
NAGASAKI TOMOO
ETO SUGURU
| JP2001294344A | 2001-10-23 | |||
| JPH0632497A | 1994-02-08 | |||
| JP2007119153A | 2007-05-17 | |||
| JP2000103535A | 2000-04-11 | |||
| JPH1111707A | 1999-01-19 | |||
| JPH0429568U | 1992-03-10 |
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