1. The printing process
At present relatively popular scrape off the printing process is: hambuger paper, printing ink on the back the pervious to light and in positive printing invoices and tax stamp printing and printing invoices and spray number and password to isolate and oil coating printing silver covering layer and pulp products.
Special invoice paper and ordinary than paper, with a high opacity and tensile strength, for all kinds of printing methods have good adaptability. In order to prevent the pervious to light the prize of the observed while regional information disclosure, in the back of the corresponding GuaJiang area invoice position, should be a layer of the printing ink pervious to light, general printed black. Then, equipment and through the automatic turn-over device printing positive content, positive first printing and printing word float or sink common words, garnish with special color fluorescent ink printing tax chapter, it is by the same printing machines of different color group to finish. Invoice number and award area by digital printing system to accomplish the content, award after spray area content, again in the corresponding position on a layer of isolation printing oil, and the last in isolation on printing silver slurry oil layer, seal isolation oil is to ensure that the silver plasma layer can easily blow away. Thus completing a scrape off the invoice printing.
2. Printing mode
Scrape off the invoice is a high quality and not easy to fake prints, application of ordinary offset printing, no water offset printing, embossed, screen printing, flexible printing and digital printing and so on many kinds of printing mode, give full play to the advantages of computer information technology strong, a modern printing mode and digital printing technology with the beauty.
Scrape off the invoice printing, common graphic content by offset printing to finish, which also contains the offset printing way without water, the equipment can be professional paper printing machine, also can be more than five turn of the offset printing machine; Number and password variable information such as digital printing system by the inkjet complete way; Isolation oil coating commonly use embossed way; Silver plasma cover of printing is open invoice printing scraping highest technical content, technology as the most difficult a link, so for its printing mode also to have certain controversial.
At present, the silver plasma cover of printing is often used to screen printing, flexible printing and printing as toppan printing mode. Domestic have the screen printing most production line, the other two ways of application also gradually to increase. Three kinds of printing mode have different features. The way of the silver screen printing paste layer edge is bright and clean level luster, level off, easy to blow open, printing the best effect. But because the screen version of itself, the processing power is low resistance to seal the difficulty of cleaning reason, improve the added value of products, will lead to its further development bring resistance. With the further development of technology and improvement, and flexible version of letterpress will with its low cost and high efficiency of the features, and gradually expand market share, the development prospect is good.
3. The technological requirements
(1) the printing speed
Because open invoice printing is the scraping of the combination of mode of printing, the printing speed should take all kinds of printing mode bear ability, so the printing speed is low, usually in 50 ~ 100 m/minutes between. On the one hand, GuaJiangOu separately printed on number, isolation oil and silver pulp layer 3 items content, equipment with the dry device is still can't meet the requirement of high speed printing; Another aspect is the high resolution digital printing, because the content of the resolution to spurt the code for 200 ~ 300 dpi, five times before the magnifying glass in can distinguish the shape of the ink point, if the printing speed too fast, you can't guarantee the shape of the ink point clear representation; Finally, in order to guarantee not leak information, ask silver plasma cover of not less than 5 ink thickness μ m, but such ink layer the drying speed will slowly, make integral of the printing speed is limited.
(2) the silver slurry ratio
Silver plasma (scrath layer ink) is by the silver and silver paint oil to certain proportion, in an electric blender mixing even under a mixture. Among them, the silver is of extremely fine at the end of the aluminum powder, and the silver oil is a sensitive to uv light of chemical raw materials. Silver in the thing on printing paste printing, which not only have to guarantee transfer in the process to have quite the transportation fastness, and to ensure that when he is easy to blow away. Silver fabic and the silver in the slurry oil in 1: general ratio 9 ~ 1:6 between, but in actual production manufacturer to its specific components will be confidential ratio, the ratio of the size and the drying units function and the quality of printing paper about. If their content smooth and flat, ratio can small some; If their content is coarser, is the amount of silver paint should be some more, ratio will be bigger. Silver pulp mainly by UV drying dry way, in silver plasma thickness certain if the oil of sensitive to UV light silver wavelength and dry installations in the light is consistent with the wavelength, the drying speed is fast and the ratio can small some; If the wavelength agreement is bad, will inevitably affect the drying speed, the ratio is a few bigger. In addition, different and silver paint the silver oil, to print out the same effect, and it is the same ratio.
Silver pulp by many variable factors ratio influence. As silver plasma layer thickness sure, the smaller the ratio, the more liquid ingredients, the more not easy to dry. But in practical production because silver pulp cover of thickness is a variable factors, so it made of silver slurry ratio are more difficult to determine. Because the more liquid ingredients, silver plasma layer can India is thinner, the drying speed is faster; And when the greater the ratio, although less liquid ingredients, but due to the difficult to achieve thin ink layer, so still can't guarantee a high drying speed. In addition, the liquid ingredients is silver pulp sensitive to uv light tone of silver oil, therefore, its content increased is also a beneficial to dry factors, so its and ordinary liquid influence the nature of the drying speed and different. Therefore, the slurry ratio of silver is a quite uncertain parameters.