| 摘要 |
PURPOSE:To prevent a photosensing function from deteriorating due to dust sticking to an element lens surface, by blowing compressed air to light emitting and photo detecting surfaces of light emitting and photo detecting elements constituting a photosensor. CONSTITUTION:Photo diode 1 as a light emitting element is fitted under the passage channel of magnetic tape 4, and beams from photo diode 1 are reflected by reflex mirror 2 and then photo-detected by photo transistor 3 as a photo detecting element fitted under the channel. Blow-off outlet 5 for compressed air is so fitted that compressed air will be blown to lens surface of photo diode 1 and photo transistor 3. consequently, the photosensing function can be prevented from deteriorating due to dust, etc., on the lens surfaces of those elements. |
