In external drum image recording devices, a movable optical carriage is used to displace an image exposing or recording source in a slow scan direction while a cylindrical drum supporting recording material on an external surface thereof is rotated with respect to the image exposing source. The drum rotation causes the recording material to advance past the exposing source along a direction which is substantially perpendicular to the slow scan direction. The recording material is therefore advanced past the exposing source by the rotating drum in a fast scan direction.
An image exposing source may include an optical system for scanning one or more exposing or recording beams. Each recording beam may be separately modulated according to a digital information signal representing data corresponding to the image to be recorded.
The recording media to be imaged by an external drum imaging system is commonly supplied in discrete sheets and may comprise a plurality of plates, hereinafter collectively referred to as xe2x80x9cplatesxe2x80x9d or xe2x80x9cprinting plates.xe2x80x9d Each plate may comprise one or more layers supported by a support substrate, which for many printing plates is a plano-graphic aluminum sheet. Other layers may include one or more image recording (i.e., xe2x80x9cimageablexe2x80x9d) layers such as a photosensitive, radiation sensitive, or thermally sensitive layer, or other chemically or physically alterable layers. Printing plates which are supported by a polyester support are also known and can be used in the present invention. Printing plates are available in a wide variety of sizes, typically ranging, e.g., from 9xe2x80x3xc3x9712xe2x80x3, or smaller, to 58xe2x80x3xc3x9780xe2x80x3, or larger. The printing plate may additionally comprise a flexographic printing plate.
External drum imaging systems have been proposed in commonly assigned U.S. Pat. Nos. 6,295,929, filed May 17, 2000; 6,318,262, filed May 17, 2000; and 6,321,651, filed May 15, 2000, the entire teachings of each reference being incorporated herein by reference. In one embodiment, with reference to FIGS. 1 and 6 of the present application, an imaging system 10 is used to record rasterized digital files onto a printing plate 18 secured to a cylindrical support surface 22. A leading edge clamping mechanism 40, actuated by an actuation system 75, is used to secure the leading edge 38 of the printing plate 18 to the surface 22. A separate actuation system 100 is used to actuate a trailing edge clamping mechanism 44 to secure the trailing edge 42 to the support surface 22.
It is proposed herein to combine actuation systems 75 and 100 into a single actuation system for beneficial reasons, such as reducing system cost and providing extra room within the imaging system.
In one embodiment, an imaging system and method for operating same are provided which includes a media support surface for supporting a printing plate during recording of an image thereon, a leading edge clamping mechanism for securing a leading edge of the printing plate to the media support surface, and a trailing edge clamping mechanism for securing a trailing edge of the printing plate to the media support surface. A single actuation system is used to actuate both the leading edge clamping mechanism and the trailing edge clamping mechanism to secure or unsecure the leading edge or the trailing edge of the printing plate.