As with the XC, the C3 also delivers a fully focused UV output to maximize the UV energy input into the ink. Both reflector profiles were designed using ray-tracing, a computerized modeling program to simulate the effects of different reflector geometries and maximize the amount of UV energy reaching the ink. This has enabled the latest reflectors from GEW to be in the region of 25 to 30 percent more efficient than others. As a result of additional development work, the C3 also benefits from a number of improvements over its predecessor, notably with regard to its heat management capabilities, the company says.
The reflector material is made up of a multi-layered dichroic coating as opposed to the polished aluminium used before. This allows infrared radiation from the lamp to be absorbed by the reflector and removed by air-cooling of the reflector’s rear surface; UV radiation is simultaneously redirected back to the web. The dichroic coating is applied to replaceable reflector inserts as opposed to directly onto the extruded reflector body, which makes them significantly cheaper to replace.
A second improvement has been the addition of a cold filter, which blocks IR radiation from the lamp and prevents it from reaching the printed substrate, allowing the UV to pass through.
Third, a “cold shutter” has been integrated into the C3 that has eliminated the risk of damage to substrates from heat when the press stops and the shutters close, according to GEW. The single-blade shutter is parked away from the direct radiation path of the lamp when the UV is running, so when the machine stops and it closes, it is cool. A layer of thermal insulation also covers the exterior of the shutter in case the lamps are left on standby for a long period of time, which prevents heat absorbed by the shutter from being re-radiated to the web.When the press restarts, the shutter opens and moves into its parked position, where it is re-cooled by the lamphead’s internal airflow.
GEW (EC) Ltd. manufactures UV curing and systems for all makes of printing and converting machines and supplies both original equipment manufactures as well as UV upgrades for existing equipment. The company is headquartered in Redhill, England.