| 摘要 |
PURPOSE:To detect securely the kind of paper on which a toner image is formed and to perform accurate fixation by detecting a maximum (minimum) output of a sensor which corresponds to the kind of the paper. CONSTITUTION:A light emitting element 8 and a photodetecting element 9 are installed opposite in the conveyance path for a form 1 to be fixed, and the form 1 passes between them. Further, a reflection type paper presence/absence detection sensor 10 is arranged right in front of the elements 8 and 9. An analog switch 12 is connected to the output side of a diode 13 of the basis of the paper presence/absence detection output O2 when paper is present or grounded when not. Then when the paper is present, VP hold the positive up-to-date peak of the detection output through the peak holding circuit consisting of the diode 13, a JFET-input operational amplifier 14, and a capacitor 15. |
