| 摘要 |
<p>PURPOSE:To achieve the improvement in resolving power and picture quality by providing a means of controlling the movement of a focusing type optical transmission body. CONSTITUTION:A pair of link mechanisms 4 which assume pantagraph form are disposed on both sides of a cathode ray tube 1 and a focusing type optical transmistion body 2 is forward and backward slidably held near the central part of their cross bar 41. In addition, the roller 5 provided to the end of the cross bar 41 is turnably contacted to the surface of a photoreceptor 3 and further the focusing type optical transmission body 2 is firmly supported at the center of the longitudinal bar 42. Then, if the distance between the stationary cathode ray tube 1 and photoreceptor 3 fluctuates owing to the deformation of the photoreceptor 3 itself, the eccentricity of the drum, etc., the link mechanism 4 deforms, causing the focusing type optical transmission body 2 to move. Hence, the ratios of the respective distances between the focusing type optical transmission body 2 and cathode ray tube 1 as well as the focusing type optical transmission body 2 and image forming plane are maintained always constant and always sharp beam is radiated onto the image forming plane.</p> |
