| 摘要 |
<p>PURPOSE:To make a device small in size and the cost low by providing a photo detector wherein light issued from a light source fixed on an end of a micro discharge tube array monitors light reflected on a record medium, and an actuator for controlling the distance between the micro discharge tube array and the record medium in accordance with the output of the detector. CONSTITUTION:An optical writing device is constituted of a micro discharge tube 6 arranged opposite to a record medium 5, a height control circuit 7, and an actuator 8. A semiconductor laser 13 as a light source is attached on one bevel of an angle-shaped section in a direction intersecting rectangularly the longitudinal direction of the micro discharge tube 6. On the other bevel, a photo detector 14, wherein light issued from the semiconductor laser 13 monitors light reflected on the face of the record medium 5, is attached. When the distance between the record medium 5 and the semiconductor laser 13 changes, the position of the light received at the photo detector 14 changes. Therefore, by monitoring the change of the output of the photo detector 14, change of the distance between the record medium 5 and the micro discharge tube array can be monitored and the distance is controlled by the actuator 8 in accordance with the output of the photo detector 14.</p> |
