| 摘要 |
A lithographic duplicating machine includes a device for feeding an imaged master from a stack of masters through a treating unit, containing conversion fluid for converting the imaged surface of the master, to a master cylinder. A motor drive system is provided for conditioning the master cylinder for operation at a printing speed and a starting speed for drawing the master through the treating unit. The motor speed is controlled by an electronic switching arrangement which receives input signals from machine responsive electrical switches and manually settable potentiometers to which the motor drive system is connected. A control device comprising contoured cams and a blocking mechanism is provided for operating the master cylinder at the starting speed, and a one-revolution mechanism including a cam operated linkage, cam discs and a follower are provided for rotating the master cylinder through a single revolution only during attachment of the master to the master cylinder while operating at the starting speed. A clamping device on the master cylinder clamps one end of the master as it exits from the treating unit and, upon completion of the conversion operation and with the master wrapped about the master cylinder, the speed of the master cylinder is operated to the printing speed. On completion of the printing operation, the master is ejected from the master cylinder and the machine is in a condition for receiving a new master for a subsequent printing operation.
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