One, LED UV printing advantage

With the increasing popularity of UV curing technology in the printing industry, more and more printing companies are concerned with the use of UVLED light emitting diode as the light source. In this paper, the characteristics of the UV LED light source are discussed, and the development of the printing industry in the future is analyzed.

Two, LED UV curing principle

The traditional UV printing refers to the photopolymerization initiator in the UV ink, under the irradiation of the UV light source, absorb the ultraviolet light of different wavelength and energy, reach the excited state, form free radical or ion. Through the intermolecular energy transfer, the prepolymer, monomer and polymer become excited state, resulting in the charge transfer complex. Complex particle continuous polymerization, process the ink curing film and adsorption on the printed matter, UV LED (Light-Emitting Diode) light source is UV light source technology toward more energy-efficient and environmentally friendly product development, is a very narrow emission spectral half width, and the electric energy into the light of semiconductor electronic components. The use of photoelectric conversion principle, obtained by the semiconductor substrate injection impurity doping growth of PN junction, the electroluminescent light emitting mechanism of edge effect, electron and positive charge in the process of moving into the light of the collision with. The radiation wave crest is single, and the light energy is concentrated in a section of ultraviolet spectrum with effective curing effect. Because the spectral half width is narrower than the traditional UV light source, the energy is highly centralized, the low heat energy, the radiation is more even. The use of UVLED light source can reduce the waste of printing resources, reduce printing costs, thereby saving the production time of printing enterprises, greatly improving the production efficiency of enterprises.

Three, LED UV printing edge

1 long life

The traditional UV light source to change in 600-1500 hours after about the frequent replacement of light source parts, may cause frequent failure at the same time curing printing machine; may also reduce the running efficiency of printing machine, printing enterprises affect normal production. The UVLED light source can be used to achieve more than a few times the traditional UV light source can reach 20000 hours, and not affected by the number of switches. According to the principle of UV light, LED light source only in one direction is energized, the forward voltage, when the electric current passes through, electrons and holes in the composite and emit light, to ensure the stability of the light source, the light decay rate is much smaller. For example, after 8000 hours of work, the luminous intensity can reach its maximum power of 95%.

2 save energy

The traditional UV printing, in front of the official printing to open the lighting system to preheat, the light power is stronger, the longer the waiting time. Part of the printing enterprises in order not to delay the duration of printing products and to maintain the life of the UV lamp, often choose not to close the irradiation system, so that it remains in the state of radiation, resulting in a large number of light source waste. The UV LED light source according to its own characteristics of the structure, the instantaneous conversion of electrical energy into light, can be started at low pressure, so there is no warm-up time, you can achieve maximum power output. More than 80% of the light source is used for curing ink. At the same time, low brightness, small calorific value. Very low light intensity can achieve the same curing effect of the traditional UV light source, can reduce the power consumption of 70% ~ 80%. High energy utilization rate. And it can be shut down when not needed to further reduce energy consumption and cost.

3 more comfortable

Traditional UV light source, calorific value, easy to heat deformation. The UV LED is a cold light source, issued a single wavelength, no infrared light, no heat radiation, does not produce too much heat. Therefore, the use of UV LED light source can significantly reduce the heat generated during the curing process, does not destroy the substrate appearance. For example, in the traditional UV equipment can not be printed on the thermal sensitive film substrate, in the use of UVLED printing can be very suitable for printing. Now the rapid development of the label printing, printing faster and faster, more and more thin substrate. If the heat is too high, the substrate will react to heat it to wrinkle, affecting product quality. The use of UV LED printing method can greatly reduce the defective rate of the product, to ensure the quality and quantity of the completion of the printing period of the task.

4 environmental protection

Now UV printing in the printing industry, a substantial increase in market share. Some of the printing enterprises in the use of high-pressure mercury lamp as the light source of UV. Factory after use cost of manpower and financial resources on the emissions of mercury are scrapped. If the treatment is not timely, it will penetrate into the surrounding environment. The mercury content of the discharged wastewater is very low, will not directly cause harm to human body; but the inside of the microorganism can absorb mercury compounds, and transfer through the food chain, fish and other seafood was eventually absorbed and accumulated. The transformation and excretion of mercury in living organisms is very slow, and it can be preserved for a long time. If this kind of eating seafood, which will seriously affect the health. The UV LED light system is not mercury and other harmful chemical elements, the work will not cause any pollution to the environment and humans.

Four, UVLED printing outlook

Although the domestic UV LED technology in many aspects of industrial and civil has shown its obvious advantages, but in the printing industry started late. Today, the UVLED market is growing at an annual rate of more than 20%, the market is expected to reach $350 million by 2020. But the UV LED light source price is at a high level, a group of UVLED lamps priced at more than ten million, compared with the traditional UV lamp is more expensive, but with the support of the UV LED ink, to choose suitable photosensitizer in the spectral range of extremely narrow, so more specific than the traditional cost, about UV ink 20%, the price is better than the traditional UV ink is a lot more expensive. Most of the printing business