Hybrid technology of the hottest offset press and

2022-08-23
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Hybrid technology of offset printing machine and digital printing machine

with the increasing maturity of digital printing technology and the continuous decline of cost, many printers have begun to try to combine traditional offset printing machine with digital printing machine to complete production. The purpose is to provide unique value-added services that can make profits and meet the requirements of preform. Combining static color offset printing with dynamic monochrome digital printing can benefit many applications, such as daily transactional printing, newsletters, labels, plastic plates, retail flyers, direct mail letters, human resources pamphlets, etc

however, there are great technical challenges in combining an old technology with a new technology. In the process of combining offset printing and digital printing, printers have to consider: which is the most ideal substrate for a technology, regular return visits of ink, and timely meeting customer needs and operating environment. These two processes can be compatible with each other only when the printing parameters are strictly controlled. The following are the determinants of how to successfully mix the two technologies:

the importance of ink

in the process of combining offset printing with digital printing, ink is the most important factor that deserves serious consideration. Although compared with paper, the value of ink itself and its impact on the profitability of a printing job are relatively weak, which may become a neglected factor, in the process of the integration of the two technologies, the characteristics of ink will directly affect the product quality

ink is the cheapest material in the printing process, but it is very important. However, the ink used in offset printing cannot bear the heat in digital printing, mainly because the ink in offset printing usually contains a large amount of wax, zero formaldehyde and resin to improve the anti friction ability. However, once the printing sheet enters the digital printing machine using electrostatic copying technology, it must withstand the test of up to 400 degrees Fahrenheit. Such a high temperature can melt the toner on the substrate, but at the same time, it also softens the wax and resin in the ordinary offset printing ink, resulting in ghosting and back rubbing, which reduces the transparency of yellow. Metal and fluorescent inks also often cause problems in digital printing, mainly because the sheet of metal ink is easy to deposit on the hot-melt roller of the printer

in order to perfectly combine offset printing and digital printing, it is recommended to use an ink compatible with laser technology to withstand excessive temperature. In order to judge the ability of ink to be compatible with laser, the service center of GATF research laboratory has developed a blocking experiment of simulating the internal pressure and heat of digital printing machine. The experimental process is as follows: clamp two samples with a clamp, and apply a high temperature of 400 degrees Fahrenheit and a pressure of 25lbs for 30 minutes. If the sample is sticky, this kind of ink cannot be used in laser imaging printers. The only difference between the two printing machines is the type of ink required: Di printing machines require anhydrous ink, while offset printing machines require ink compatible with laser technology

drying and curing

laser compatible inks generally contain little or no wax or resin, so the anti friction ability of this kind of ink is low. It can be treated to better carry out post press processing, such as polishing on the print or water-based coating to seal the ink and toner. Experiments can be carried out to find the most suitable method and formula

after offset printing with ink compatible with laser technology, sufficient drying and curing time is required before the printing sheet enters the digital printer, generally 24 ~ 72 hours. Printers must reduce the amount of powder spraying as much as possible, because digital printers are extremely sensitive to this pollutant

most equipment manufacturers want users to use digital printers first in the production process, and then complete color printing on the traditional offset press, so as to keep the drum clean. However, some prints need to overprint black fonts in the color area, so the offset ink must be completely dry before the print sheet enters the digital printer, otherwise the back will rub dirty

in order to save production time, printers can use offset printing to print a large number of book covers, which can be preserved after coating and lamination, and further processing can be completed by digital printers when necessary. But this method is only suitable for those printing activities that do not need to change the cover design. Otherwise, it will lead to waste of time, ink and paper

speed requirements

if you already have a stable offset press, but want to provide customers with variable data printing services, what kind of digital printer should be selected to match the existing equipment? The answer is: digital printing machines that can keep up with the speed of offset printing machines, at least not much lower than the speed of offset printing, otherwise it will lead to a decline in profits. This criterion is more practical especially when the digital printing press is connected with the offset press

if only monochrome variable data information is processed, and there is an offset printing machine, if there is another digital printing machine with high speed, it is very ideal to combine digital printing with offset printing. Xeikon's varypress printing machine is often online with offset printing machines, with a speed of 300 ~ 400fpm. It is generally used for the production of commercial forms and transportation labels. If we have to reduce the speed of the offset press by 2/3 in order to adapt to the speed of the digital press, it will be at the cost of losing production efficiency

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