| 摘要 |
<p>A rotatable drum for use in a plotter, or similar device, that provides vacuum for holding the film or other media to the drum's surface, so as to easily accommodate films of various sizes. The drum includes first and second journals (10) and a plate (7) mounted on the circumference of the first and second journals. At least one of the journals has defined on its circumference circumferential channels. The plate (7) has interior and exterior sides, and the first and second journals and a portion of the plate's interior side define a chamber (3). The plate's exterior side has defined thereon a plurality of grooves (72). In one embodiment, at least one of the grooves, associated with a first film size, is in fluid communication with the chamber (3), and some of the remaining grooves, associated with the larger film sizes, are in fluid communication with the channels. A vacuum is supplied to the chamber, and a valve (50) is provided for controlling fluid communication between the channels and the chamber.</p> |
