UV-hardening technology for industrial applications since the early 1960s, Germany's use of wood in the wood until the surface coating layer sclerosis. The world's first use of UV lithography in the United States, Britain was in 1970 the company successfully used (Holland, 1997). And traditional offset printing, compared to only be regarded as a very young new technology, but it has become a very important printing technology. In general, UV is not specifically applied to lithography, it is a UV light exposure to chemicals, and the chemicals were contained in dirt, "says agent before (Photoinitiator)" by UV light stimulation, at very short time (less than 1 second) so that the chemicals contained in the "monomer polymerization (Polymer)" have glue hardening "of radiation-hardening technology (Radiation Curing)", commonly known as UV-hardening (UV Curing). The international community will be with the "electron beam hardening technology (Electronic Beam Curing)" attributed to the same, collectively known as UV / EB Curing. UV-hardening can be used in a variety of traditional print format, including Toppan Forms, Toppan flexibility (Flexo), lithography, screen printing, etc., as long as the use of UV inks, with UV light to complete the major part. UV lithography printing that is the structure of lithography, the use of UV inks, with UV light source from, of course, with some very important conditions need to be reached at the same time. In addition to printing, the use of transparent materials for UV printing materials is also polishing the market widely used way of polishing.

     First, the characteristics of the printing UV lithography

    In general, UV printing with the advantages: 1. High color saturation, color effect. And compared to traditional offset printing, lithography can be relatively high UV printing color effects, more stringent requirements for the color of the print, will be more satisfactory results.

   2.印纹high-gloss, visual Yanli. And background with extinction, it will be exciting visual contrast enhanced products for high-quality image, a very useful (Tolliver, 1998).

   3. Applicable to the physical properties and the resistance is totally different from the many types of printed materials, including paper, cardboard, plastics, game road network, PVC, PE ... ... such as paper and film category. This features than the traditional offset printing to print more product categories, there are more possibilities for the future of the market.

   4. At the same time in a printed immediately dry, can significantly improve production efficiency (RadTech, 1998). As a result do not need to wait for ink drying time, it can significantly shorten production time, printing companies can also save a lot of storage to be dry for printed materials space, cost savings of more than helpful.

   5. Because of printing as soon as dry, there was no need to use the spray, because the powder to improve the quality problems caused by, can be avoided.

   6. Because of printing as soon as dry, it can not be as traditional offset printing in general, and India down within 48 hours of color changes will happen (Ehrlitzer, 1998).

   7.印纹of lightfastness better.

   8.印纹rub of better abrasion resistance.

   9. On the environment and a more pro-(RadTech, 1998).
In addition to the merits of the aforementioned, whether or not printed in lithography UV no flaws? The answer is that it would certainly get some shortcomings:

   1. Lithographic printing machine UV investment cost than traditional offset printing equipment, high, investment decision-making to be more careful.

   2. You can use UV lithography printing market types than the traditional offset printing market broader and more dispersed, so manufacturers to put the development of this technology, it should first conduct a market analysis, so as not to invest in equipment orders can not find the risk of occurrence .

   3. Lithographic printing UV ink cost of traditional offset printing ink cost of about 3 to 4 times, material costs are high. Printing production management techniques of production, process technology, and cost control, the need for more stringent, or the proportion of the cost of wear and tear than conventional lithography high.

   4. Ink storage area needs to carry out more strict temperature control, to be maintained at below 20 ℃, storage costs are relatively high (HostmannSteinberg, 1992).

   5. UV leakage of staff will have health implications.

   6. Lithography UV printing is not as universal as traditional offset printing, familiar with the operation of technology, manpower supply and training need to rely on their own. In general, UV printing technology will be applied to the types of references to the following simple:

   1. UV light source equipment: including lamp, reflector shield, energy control device, temperature control device (or cooling).

  (1) Lamp: UV light tubes used, the most commonly used for internal types of mercury tube filled with mercury (Mercury Lamp), sometimes add other metals, just like gallium (Gallium). In addition metal halogen tubes, and the quartz tube (quartz lamp) is also commonly used types. At present, more dependent on imports. UV lamp of electromagnetic waves emitted by a long range to be between 200 ~ 400nm.

  (2) Reflector: Reflector for the major functions of UV reflection of electromagnetic waves to come back in order to increase the efficiency of UV light (UV Tech Publications, 1991), another important function to maintain the lamp operating temperature. Reflector usually aluminum surface reflectivity requirements normally takes up to 90%.

    Reflector There are two basic types, one for the Focus model, and the other for defocusing type, with the manufacturer's development and extension of other types.

  (3) energy control device: This device can control mainly for the UV lamp emits energy of the UV stability in order to maintain the efficiency and stability of hardening to cater for different needs of the printing speed. Electronic design, but also the use of microcomputer control. 2. Cooling device: As the UV lamp on the issue of UV electromagnetic waves, it will also issue a IR (infrared wave), makes UV equipment will operate at high temperatures (for example, the temperature of the quartz tube up to 600 ~ 800 ℃), so in addition to shorten the life span of equipment, and the printed materials are also easily lead to scalable, resulting in digital printing Regulation can not register, so the importance of cooling device can be seen.
3. For the ink system:

    As a result of UV ink than traditional lithography inks have a higher viscosity, and the greater the friction, and the components of the printing press (including blankets, roller, etc.) will damage not only to deal with printing ink tank of Mexico should continue to carry out mixing, the ink system for ink roller and blanket should be used should be designed for UV printing.

    Also in order to maintain the stability of UV inks, so as to avoid excessive temperature of the viscosity of ink, ink roller temperature control device is also important equipment.

 4. Cooling and exhaust devices:

    The main functions of the internal machinery and due to excessive heat generated when the ink polymerization hardening rule out use of ozone. Usually by the exhaust motor and exhaust pipe formed.

  5. Ink:

    Ink quality is good or not is a direct impact on UV printing the most critical factor. It not only affects the color gamut performance and quality of traditional factors, the Printability ink was even more direct impact on India and India in a printed material印纹after the completion of the adhesion, strength, anti-friction and so on. KPS before monomer polymerization agents and the types and characteristics of the basic materials for the key.

    To control the adhesion of UV inks for the wet and the UV ink printed material contact, was printed the surface tension (unit: dynes / cm) must be greater than the ink surface tension (Schilstra, 1997), in order to produce good ink adhesion, so control of ink and is printed for the surface tension of the important UV printing technology.

   6. UV energy measurement equipment:

   UV printing on them, because the UV lamp aging, power, speed printing presses and other factors, the need to control the UV energy to maintain stability, so measuring UV energy technology as a very important part.

   7. Foreign technology development trends:

  (1) the growth of market stability.

  (2) the application of multi-color printing and high-precision performance of the separation technology. Including Hi-Fi Color, and random dots over the net technology (Stochastic Screening Technology).

  (3) cold UV hardening technology (Cold UV Curing) (Holland, 1997):

    Heraeus company Excimer Lamp, will not have infra-red, it will not be fever, for the film print or prone contraction effect of the printed material, effective best place to control the outcome of regulatory and other advantages are: energy, will not erode the press parts, not to issue the smell ... ... and so on. However, to date its effectiveness can not be replaced by mercury tube, the future development potential.

    Under the current version of the use of UV printing situation, with traditional offset printing, compared to belong to a very small number of technology types. So far, specifically for the installation of UV lithography printing features designed by the manufacturers rarely lithography presses, the majority of magnetic cards for use in production, film, and high-quality cosmetics packaging boxes.

    Domestic printing company to use more UV lithography applications, the majority of applications in the use of glazing, they were mostly off-line UV coating type. When the traditional offset printing to complete the printing of paper printed needs to deal with high-gloss polish (including full and partial glazing glazing), the majority used in this way. Its smaller amount of investment, and most of polishing plant investment, so do not have to invest in printing company, and polishing factory because equipment can play a more efficient and cost-effective. The shortcomings of the production process for long, and the quality of instability. Due to the use of traditional offset printing dusting, polishing the effect it will be affected. This combination of more than applies to commercial advertising, such as printing and packaging.

   At present, UV lithography printing technology on the domestic use of the current status of the device is no longer a big problem. As the leader in the international arena (such as printing presses: Heidelberg, Roland; UV equipment: IST METZ, Eltossch, Spectral; UV lamp: OSRAM ... ... etc.) have the professional integrity of equipment, these devices have also been experienced foreign the printing company's most stringent tests of efficiency and stability of their use is no longer a major issue, in addition to equipment, the high amount of investment this financial problem. At present, UV lithography printing technology issues, mainly in material supply and other related issues Printability