12 May What Type of Construction is Your Computer-to-Plate Imagesetter?
Making the switch to a new plate could be a solid financial decision to improve overall production.
Businesses worldwide continue transitioning to digital technologies. The printing industry is no exception. But as technology advances and needs for Computer-to-Plate (CTP) increases, companies face more choices than ever before. More often than not, weighing the best options can be complicated. Manufactures are not only introducing new imagesetters to the market but creating different CTP methods.
CTP techniques differ based on two factors — the construction and the light source. Buyers can choose from three different kinds of equipment solutions, including an internal drum, external drum, or flat-bed imagesetters. There are also two main light sources — ultraviolet light lamps and laser diodes to expose the plate. In deciding what solution best meets your business needs, there are also additional factors which come into play, including price, maintenance costs and environmental concerns.
Here are the ways CTP construction varies:
Internal Drum Imagesetters
With this process, the plate is placed in a cylinder and the imaging head — which rotates around its axis to expose the plate. A rotating mirror at the end of the imaging head, positions the laser on the desired part of the fixed plate. This construction method can make it more difficult to use several lasers simultaneously, however operating one laser has advantages, such as providing a uniform beam intensity over the entire plate surface throughout the duration of imaging.
External Drum Imagesetters
This type of construction is a bit simpler. The plate wraps around a drum which rotates around its axis. At the same time, the imaging head — which projects the image onto the plate — moves along the axis and focuses the laser beam on the plate surface. External drum CTP image setters make it possible for machine operators to arrange multiple image heads next to each other and concurrently use several image heads. External drums also decrease the time it takes to expose images to entire printing plates.
This CTP solution allows an image to reproduced line-by-line on a fixed, flat printing plate. The laser beam is redirected by a rotating polygon mirror and then onto the plate. As a result of this setup, the laser beam can be less accurate along the printing plate’s edges. Typically, printers use flat-bed image setters for smaller images where high-quality output is not as critical. Industry experts and technicians suggest setting customers’ expectations before utilizing this technology.