New process for packaging and printing

In the field of packaging and printing, even in the fast-growing short-run printing market, many sheet-fed offset presses are equipped with flexo coating units. The flexo printing unit is equipped with closed doctor blades and anilox rollers, and not only Coating on glazing, but also able to overprint a good print. The usual usage is that the flexo printing unit at the back of the offset printing unit is used for on-line coating or other effects of the printing; and the flexo printing unit at the front of the offset printing unit can perform surface preparation on the printing material, such as gold and silver cards. The paper or transparent plastic surface is coated with a layer of opaque coating, followed by an offset printing process. Prior to printing, the substrate is treated with pearlescent coating to produce a creamy effect on the printed image. This is a method of processing that is of interest to many fashion clients.

The advantages of offset printing are good print quality, low cost before printing and printing plates. On the other hand, flexographic printing has its advantage in that the ink layer is thicker, so that more pigments enter the interior of the substrate and the machine structure is simpler. The viscosity of flexographic ink is very similar to that of gravure ink. Compared with offset printing process, the flexographic ink layer is thicker and even forms a layer of ink “coating”. The ink layer thickness changes with the change of the anilox roller. The diameter of the metal pigment particles in the offset ink is at most 3.5 μm, while the metal pigment particles of the gravure and flexo inks can reach 9 μm. The main uses of the flexo printing machine on the offset printing press include white ink primer, pearlescent coating, foam coating, metallic gloss coating, UV coating, and waterborne coating.

The development of a sheetfed offset printing machine equipped with a flexo printing unit as a simple sheet-fed flexo/glazing machine is in line with the development of logic. Sheetfed flexo presses are common in corrugated board printing. In addition, the new packaging printing sheet-fed offset printing machine is equipped with a gripper paper delivery system to ensure that the paper is accurately transferred between the units. The printing range extends from plain paper to 1.25mm thick cardboard.

The structural design of the sheetfed flexo press is similar to that of a sheet-fed offset press equipped with two flexo printing units. It can also be used solely for UV coating or other effects. Special glazing processes require thick coatings, such as glazing, glazing, sizing, pearlescent glazing, and metallic glazing, which require precise coating thickness. If the glazing method is often replaced, two glazing units can be provided, one for waterborne glazing and the other for UV glazing.

High-quality packaging and printing processes generally go through many processing processes. Therefore, most of the printed products must go back and forth several times between the glazing unit and the flexo printing unit. If the flexo printing machine is used for coating and multi-color printing, the production process The "bottleneck". In terms of technology, the use of off-line sheet-fed flexo presses is an option for the high-quality packaging and printing market.

UV print sales have grown at a rate three times that of conventional offset products. UV technology represents high quality. It means high efficiency in on-line processing, uniform product, no harmful substances volatilization, and good environmental protection. In particular, UV glazing can be fixed instantly, making the product more glossy and has good wear resistance.

However, the use of UV printing technology requires training of new technology for employees, increased equipment investment, material and UV curing costs, planning of the timing between conversion of UV printing and conventional offset printing, and adjustment of printing characteristics, reducing the odor of UV prints is UV printing Problems to be solved. However, the advantages of UV printing far outweigh the disadvantages. Especially for packaging printing, due to the large number of non-absorbent printing materials used, this poses a severe challenge to packaging design, packaging printing and label printing.

UV printers need some adjustments to suit different printing manufacturers and print requirements. UV printing units can be combined with small format, medium format, and wide format offset presses. For beginners of UV technology, we recommend that UV printing and conventional offset printing be used at the beginning to ensure that the primer coating layer meets the requirements of the UV printer. In the future, the waterless UV sheet-fed offset press will also prove its advantages in packaging printing and processing, especially printing non-absorbent substrates. With the wide acceptance of UV technology, it will promote the application of waterless UV sheet-fed offset presses. UV technology also includes CTP waterless version and CTcP and other technologies.

The demand for plastic film printing is on the rise. In the past, this was a monopoly market for screen printing. With UV technology, offset printing manufacturers can also be involved in this market. Because the high temperature of the UV lamp affects the stability and registration accuracy of the substrate, a new UV curing system is now available. The ink or varnish can be cured in an enclosed chamber filled with inert gas or nitrogen, reducing the UV lamp. Tube performance requirements.

In addition to a single UV-curing device on the market, dual-cure devices are now available, making it possible to perform on-line UV glazing on conventional offset inks at a significant cost reduction. After testing, special colors of ink surface can also be UV glazing, provided that the printing machine must have 2 coating units with a drying zone in between.

Mixed inks Focused processing technology

Another noteworthy new technology for on-line processing is the HyPid ink technology, in which traditional mineral oil inks and new hybrid inks can be used simultaneously on a sheet-fed offset press, provided that the press passes through The conversion. Since the chemical properties of the mixed ink surface are virtually the same as those of the UV ink, the ink does not swell the rubber blanket or the rubber roller at the same time as overcoming problems such as weak bonding and poor print glossiness.

To achieve film effect

Until now, miss-printing techniques, such as screen-printing techniques, are common techniques for achieving plastic-like texture effects. However, compared to sheet-fed offset printing, they have lower production efficiency and are therefore not suitable for printing medium or large batch jobs. To this end, KBA experts will work with printing ink manufacturers Sun Chemical and Epple to launch a solution for large-volume sheetfed offsets: printing images, text, or other images in a printer's first color group with mixed inks Highlighted parts; then dried and cured by a UV dryer; printed in a later color set with a conventional oil-based offset ink/varnish; and finally UV-cured and UV-cured. In the final print, the text part printed with the mixed ink can achieve high gloss, which can only be achieved through double-layer coating before, not only taking up more equipment resources, but also consuming more Power and energy. The graphic part after printing with oil offset ink will show a matte and matt effect under the interaction of conventional ink and UV varnish. If a special kind of varnish is used, even a film-like effect can be achieved even in visual and tactile sense.

Low investment in local glazing

The use of a hybrid ink system allows for partial coating, even if the coating has a complex shape, it can be obtained by only one polishing mechanism. In the past, the need for a special printing plate for spot-off offset printing, such as a photosensitive resin plate made by a professional company, or a hand-sculpted glazing plate, was not only expensive to make, but also required an increase in the plate time. The new technology can use two different inks at the same time, using two ink printing graphics to form a sharp contrast on the gloss, to achieve the purpose of local glazing.

Offset manufacturers are always faced with some problems when providing services for printing customers. They need to provide value-added services, prices must be reasonable, and the printing effect must be different. As the printing machinery adopts a modular structure, this lowers the threshold for entry into the above UV technology. Therefore, the upcoming Drupa 2004 is an ideal place for you to weigh all processes and understand the overall overview of inks and offset presses. After all, UV technology will infiltrate commercial offset printing in the coming years.