UV curing (UV curing) refers to the use of
UV light to stimulate the polymerization of monomers in ink into polymer, which
is a technology of curing ink droplets. In recent years, with the continuous
improvement of digital imaging technology and the rapid promotion of its
application, the application of UV curing technology in the China Printing field has
been promoted, and good results have been achieved. Due to the characteristics
of rapid curing, high efficiency, low pollution, energy saving, UV curing
material has rapidly developed into a new type of digital imaging material.
In order to meet the needs of modern
printing industry, manufacturers use the advantages of ink-jet technology and
UV curing technology to combine ink-jet printing head, printing device, UV
curing system and UV curing ink, thus forming the UV curing ink-jet printing
technology. With the emergence of UV curing technology, the printing speed of
UV ink-jet printing has been greatly improved. UV ink-jet printing is being
adopted by more and more printers in China Printing. It can be
said that UV curing technology has saved the ink-jet printing and can be
applied to a wider and newer market and field.
UV curing device
1. UV lamp device
The important part of UV curing device is
UV lamp device. The lamp device should meet the ideal design requirements. The
specific requirements are as follows.
1) Miniaturization design, compact
equipment design. The UV lamp installed on the small inkjet printing machine
must be a non volume structure and easy to assemble and disassemble. The
accessory equipment, such as the cooling and blowing device for the lamp,
should also be small, with small air volume and no impact when the ink is
ejected from the printing head.
2) Can be set in the office, as a copier to
apply.
3) Cool the air. In order to keep the
surface temperature of light valve constant, it is necessary to cool the
surface of light valve in UV system, and air cooling is often used.
4) It can be imaged on any substrate: for
the substrate without heat resistance, or the substrate with wrinkle caused by
rapid evaporation of moisture in the substrate due to heat, a low heat UV lamp
device should be used.
5) Stable images can be obtained without
skilled techniques.
6) The stability and long life of the light
output. UV curing reaction is affected by illumination, luminescence spectrum
and curing temperature. It is very important to use strong light and ensure the
stability of the luminescence spectrum in the use time. The key factors to
ensure the stability of illumination and luminous spectrum are the luminous
valve itself, optical system and the stability of power supply to the luminous
valve.
7) High illumination output and spectrum
matching. In order to obtain high quality output image, the high illumination
output from UV lamp is required to match the spectral band needed for curing.
This is due to the advantages of high-intensity UV lamp irradiation. According
to most studies in Europe and America, high-intensity UV lamp has a certain
effect on preventing oxygen barrier, and is beneficial to improving the curing
speed.
2. UV curing process in
The UV curing process is as follows: 1)
firstly, the UV ink is sprayed onto the substrate surface: pigment particles,
photoinitiators, monomers and prepolymers; 2) then, the UV photoluminescence
initiators become free radicals and react with the monomers and prepolymers; 3)
the monomers and prepolymers continue to react to form photosensitive polymer;
4) finally, the UV ink is dried and the pigment particles adhere to the
substrate Substrate surface.
