| 摘要 |
PURPOSE:To eliminate the effects of disturbing light, by driving a light-emitting part by a driving signal having a predetermined signal format, and detecting an optical signal from the light-emitting part corresponding to the driving signal by a light-receiving part. CONSTITUTION:A recoding part P is provided with an optical detector 23, and a medium detection signal Vo outputted therefrom is inputted to an MPU 50. When a light-emitting part 33 is driven by a light emission control signal and a recoding medium is inserted in a predetermined timing, the light emitted from the light-emitting part turned On and OFF is a timing corresponding to the light emission control signal Vi is reflected by a recording medium and strikes a light-receiving part 34, so that the medium detection signal Vo outputted from the light-receiving part 34 becomes a pulse having substantially the same ON/OFF timings as those of the light emission control signal. Accordingly, the effects of disturbing light can be removed by detecting whether a light reception signal has a signal format corresponding to a driving signal for the light-emitting part. |
