PURPOSE: To prevent scattering of press plates by a method wherein a light sensitive material is mounted on a rotary drum and an evacuating means is stopped, then, abnormality in the drum is judged by an internal pressure-detecting means after a certain period of time has elapsed while picture recording process is prohibited when an abnormality is recognized.

CONSTITUTION: A blower is operated to suck and discharge air in the inner chamber of a rotary drum 1 and, subsequently, a motor is driven so as to be rotated into normal rotation to wind press plates S around an attracting section. After the drum 1 is turned by a specific angle, the motor is stopped and the rear ends of the press plates S are inserted by a transfer mechanism into a rear end pressing member. Next, the rotary drum 1 is driven by the motor with a low-speed to stop the drum 1 at a position capable of detecting a sensing plate 21 in an internal pressure detecting unit 20 by a photosensor 30 and, successively, the blower is stopped. After certain period of time has elapsed, the voltage of the photosensor 30 is detected and when a specific voltage is outputted, it is judged as normal. On the other hand, when the press plate is not wound around the rotary drum 1 or there is the leakage of suction, the sensing plate 21 is pushed outwardly to intercept the light path of the photosensor 30 and the output becomes zero, whereby the abnormality of the internal pressure can be judged.