UV lamps
The purple down-line launcher is generally a quartz tube containing mercury in an inert gas atmosphere. The transparency of high-quality quartz can ensure that 90% of ultraviolet rays can pass through, and can withstand high temperatures of 800 ℃. Mercury is used because the radiation it emits cures the colors commonly used in printing over the entire spectral range. For special applications (such as opaque white, thick ink film and special colors), doped lamps (cobalt, calcium, indium, iron, lead) are required. UV lamps need a transformer to provide several thousand volts of current.
UV mercury lamps are very reliable, but their output will continue to decline with use. The attenuation is related to (a) the number of operating hours, (b) the number of start-ups and shutdowns, (c) the efficiency of the cooling system, and the cleaning procedures of the lamps and reflectors. Generally speaking, depending on the supplier and the type of lamp, the guaranteed service life of the lamp is 1000 to 1500 hours. The new generation of UV lamps use a cyclic halogen process, which greatly avoids the edge blackening (due to electrode corrosion) and significantly delays the internal pollution of the entire lamp (electrode material deposition). If the lamp is correct Maintenance can achieve a very long service life.
The high rated power of the lamp does not mean that the system can provide high UV efficiency and generate low heat at a certain energy consumption. Efficiency depends not only on the power rating of the luminaire, but also on the quality and system performance of the luminaire-this indicator varies according to the supplier and design, which affects the efficiency of curing and energy, such as:
– To reduce the cost of electrical standstill and the risk of fire, the lighting system should be equipped with a shutter that can automatically shut down when the printing press is shut down. After the shutter is installed, the position of the lamp can be as close as possible to the printing material, which can improve the efficiency by 20% (it also requires less cooling and less energy than other designs).
– The profile curve of the reflector should be able to focus the radiation to obtain the highest radiation intensity. The ideal situation is to minimize direct radiation and focus the highest intensity on a narrow area.
– First of all, high-strength curing is required, because it can quickly seal the ink surface to reduce the effect of oxygen suppression (otherwise the diffusion of a large amount of oxygen will deform the polished surface).
– Avoid pre-radiation and increase the power required for main curing.
– Back radiation is only recommended for heat sensitive materials that may cause registration problems due to heat generated by curing between the units.
Reflective plate
Only about 35% of the lamp radiation is directly transmitted from the lamp to the printing material (basic energy). The remaining (secondary) energy is reflected on the substrate through the reflector. The efficiency of the entire lamp is determined by the nature of the reflective material used and the profile curve of the reflector.
The reflector should provide maximum UV curing radiation with minimum energy consumption and minimal heat accumulation. The decisive factor in curing is the amount of ultraviolet light that reaches the printing material. The UV module should be as close to the printing material as possible, because increasing the distance from the surface of the printing material will greatly reduce the UV intensity.
Most UV reflectors are made of aluminum or glass, and their reflection performance is basically equal. Aluminum is used a lot, because users can replace the reflective plate by themselves when the reflective plate is dirty (glass requires professional technicians to replace it), and there is no need to worry about the glass falling onto the printing machine when the reflective plate breaks. For the heat-sensitive printing materials, a selective mirror of a dichroic reflective coating is used to reflect ultraviolet rays and absorb most infrared rays.
Module
The new-generation UV module optimizes the contour curves of the elliptical reflector and the object reflector, improves the strength, and reduces the back radiation to reduce energy consumption (such as LightGuide by Adphos-Eltosch). The updated module can be easily moved between docking stations, and the disassembly and assembly time does not exceed one minute. The plug-and-play connection allows the module to be used as a drying module between UV units for one use, while the UV module at the end of the printing press is used for another purpose. The UV lamp itself also has a plug-and-play connection, which allows the lamp to be replaced for no less than one minute without the use of tools.
cool down
The surface temperature of UV lamps can reach 800 ℃, and it needs to be cooled effectively to avoid damage to the printing materials or printing system. The water cooling system absorbs most of the energy produced by infrared rays. The cooling water is basically pure (mineral free) and free of bacteria.
Curing system control
The precise UV dosage should match each ink color at various printer speeds. The control system should allow each UV lamp output module to be individually programmed to achieve extremely precise doses (especially on the radiation used for heat-sensitive printing materials), plus each UV of the UV drying device at the end of the printer The modules can be programmed separately. Other required functions include: stepless output adjustment of the dimmer; the assembled shutter system can prevent the radiation line from entering the printing machine while the printing machine is waiting for operation; monitor.
Special lamps and modules
TwinRay: A new curing concept that allows different UV lamps to be combined in one module to eliminate heat problems related to infrared energy, including registration, paper ripples, high stack temperature and stacking issues For printing materials that are sensitive to heat.
WhiteCure: The UV curing opaque white absorption range used when printing plastic films is different from standard UV inks (white pigments in different ranges absorb better than standard colors). This means that it will compete with the photoinitiator for energy during curing. Higher energy is usually used to ensure that curing proceeds, but this can cause problems on heat-sensitive printing materials. The specially doped WhiteCure UV curing module (inserted into a standard light fixture) can improve the curing performance of opaque white by 25%.
Ningbo XISXI E-commerce Co., Ltd , https://www.petspetsproducts.com