Abstract: An imaging engine for a platesetter comprises an imager for exposing a line of the plate that extends transversely across the plate. The plate is supported on a belt adjacent to the imager. The belt moves the plate to scan the line from the imager laterally across the plate. A vacuum platen is provided under the belt to pull the plate against the belt. The belt is the preferably porous to transfer the vacuum provided by the platen to the plate, to thereby pull the plate against the belt. Variable depth vacuum grooves can be utilized to provide a more constant vacuum across the platen. The belt is preferably supported by a first roller and a second roller that tension the belt under the imager. A detent system is provided to lock the rotation of the rollers to the movement of the belt. In this way, by using a high precision encoder in the drive motor, the belt can be positioned to the resolutions required for high resolution imaging of the plate.

Abstract: A method and apparatus automatically switches from one web media type to another, using a single drive roller to access and drive one of two web media supply cassettes mounted within an imaging system. A gear motor and eccentric shaft position and load the drive roller against either of two driven rollers. The media is nipped between the drive roller and one of the driven rollers and is advanced by the drive roller into the imaging system as needed. To switch media supply cassettes, the media is cut beyond the drive roller. The media is then drawn back into the supply cassette to free the media path for the alternate media to advance from the other of the two media supply cassettes.