ข่าว บริษัท เกี่ยวกับ UV LED curing in offset printing

Offset printing is a printing process with a thin ink layer, mainly used for high-precision color commercial printing on flat materials such as paper and cardboard.

A factory specializing in color printing for high-end wine and cosmetic packaging uses traditional UV mercury lamp offset printing presses. Their main challenges are:

• Production efficiency bottlenecks: The mercury lamps require warming up and cooling down, resulting in long job changeover times.
• High energy consumption: Mercury lamps consume significant energy and require complex exhaust systems to dissipate heat.
• Substrate limitations: The high temperatures generated by the mercury lamps can cause deformation of films and some synthetic papers, limiting material choices. The factory decided to upgrade some of its offset printing units to UV LED curing systems.

1. Ink/Light Source Matching: Changing inks and fountain solutions: Traditional inks are replaced with offset inks and varnishes specifically designed for the UV LED wavelength (typically 385 nm or 395 nm). The fountain solution formulation is also adjusted to suit the LED ink system. The UV LED must emit at the precise wavelength that corresponds to the absorption peak of the ink's photoinitiator.
2. System Integration and Installation: Replacing the Light Source: Traditional mercury lamp-based UV drying cabinets are removed and replaced with highly compact UV LED modules. These modules are installed between printing units (inline curing) or before the delivery unit (final curing) in the printing press. The LED modules must be extremely small and highly integrated to fit within the confined space of the press.
3. Heat Dissipation and Safety Configuration: An efficient heat dissipation system: Although LED curing emits less heat, the chip itself still requires efficient heat dissipation. The system is equipped with water cooling or high-efficiency air cooling to ensure stable operation of the LED at high power output. Good thermal management is critical to ensuring LED life and stable output.
4. Power Optimization and Adjustment: Irradiance Adjustment: Engineers use a radiometer to precisely measure the peak irradiance (e.g., W/cm²) and energy density (e.g., J/cm²) of each UV LED module in each printing unit. The goal is to adjust the power to the lowest effective curing level to conserve energy and optimize ink performance. This ensures that, at high line speeds (e.g., 18,000 sheets/hour), exposure times are extremely short, yet peak power is sufficient to initiate curing instantly.

Shenzhen Super-curing Opto-Electronic CO Ltd UVLEED enables ultra-high-speed production, ensuring that even at high speeds (e.g., exposure times of 5-10 milliseconds per second), UV energy is sufficient to thoroughly cure thin ink layers, achieving "instant dry" results.

• Instant On/Off Switching improves production efficiency, eliminating the 5-10 minute warm-up and cool-down time required by traditional mercury lamps. The machine can be started and stopped instantly, significantly reducing job changeover time.
• Cold Curing expands the range of substrates. Producing virtually no infrared heat radiation, it enables stable printing on temperature-sensitive materials such as film, thermal labels, and synthetic paper, increasing product value.
• Environmentally friendly and mercury-free, it complies with regulations and reduces costs. It completely eliminates mercury vapor and ozone emissions. Eliminating complex exhaust/ozone systems reduces equipment investment and ongoing maintenance costs.
• Lower Energy Consumption significantly reduces operating costs. It uses energy more efficiently than mercury lamps and only turns on when printing, significantly reducing electricity consumption.