Talk about the combination printing technology bas

Talk about the combined printing process based on flexographic printing

with the continuous strengthening of people's aesthetic outlook and the continuous improvement of environmental protection requirements, the green printing extended from green tobacco has developed rapidly. The combined printing process based on narrow flexographic printing is widely used in the packaging of medium and high-end soft cigarette boxes (such as Honghe 88, Honghe 99, treasure Baisha series, etc.) because it meets this requirement

it is well known that flexographic printing is famous for environmental friendly water-based ink printing. Printing is characterized by thick ink layer and wide range of substrates. Offset printing is characterized by strong layering and soft transition. Gravure printing is characterized by thick ink layer and high printing resistance. Therefore, the combination of flexographic printing and silk printing, the combination of flexographic printing, silk printing and gravure printing, the combination of flexographic printing, silk printing, gravure printing and offset printing, and the combined process of wire transfer, cold pressing and die-cutting units have emerged

among them, the combined process of the combined printing line transfer, cold pressing and die cutting unit, which mainly focuses on flexographic printing, is a new integrated process that optimizes the combination of the four printing methods according to the product characteristics, and focuses on flexographic printing. Let's discuss the characteristics of the combined printing process with our peers

characteristics of combined printing process

1 The difference from the single printing process

the combined printing process based on flexographic printing adopts the web printing method, and the substrate is mostly 80 ~ 100g/m2 web coated paper. The selection range of substrate is relatively single, and the paper printing method is relatively narrow; The ink system is mainly water-based ink, combined with ester, alcohol soluble gravure ink, UV offset ink and printing ink. Compared with the single printing method, the viscosity, product hue and drying condition of the combined system are more difficult to control; The structure of combined flexographic printing machine is very similar to that of web gravure printing machine, which is generally composed of unwinding part, flexographic printing unit, printing (gravure printing, offset printing) unit, glazing unit and registration, die cutting, waste discharge and winding part. The machine speed is relatively slow compared with a single printing method; However, the movable operation control panel and selective optimization combination are incomparable to a single printing method, especially its enhanced connection transfer, cold pressing and die cutting functions avoid the defects of a single printing method, such as long production cycle, complicated processes, easy paper deformation and many registration wastes

2. The same with the single printing process

flexographic printing, offset printing and printing unit have relatively low printing resistance, the tension between flexographic printing units is not easy to control, and the color phase of gravure printing unit is stable. These characteristics are the same as the printing process of single offset printing, gravure printing, printing and flexographic printing

difficulties of combined printing process

1 Calculation of the amount of registration and scaling between different printing methods

for a product printed by combined printing process, when the process route is designed, then the printing plate is made. When the flexo, gravure, offset, silk plate, polishing plate, embossing plate and die-cutting plate are made according to a single printing process, according to the paper, printing environment, machine, registration accuracy requirements and previous practical experience, They all have their own scaling parameters. When several printing methods are combined, the previous scaling parameters can only be used as a reference. The plate making parameters must be preliminarily determined according to the paper used, the ink drying method of various printing methods, the normal machine speed, and the selected plate material. Through proofing, re explore new parameters, find the best scaling between various plates, and then check the resistance, energy consumption resistance After measurement, this work is the most critical and difficult for combination printing. Generally, the paper with stable performance (including the base paper for lamination and transfer) and the ambient temperature and humidity are first determined, and then the small sample version is made according to the individual zoom of each printing method and the combination of the plate, printing film and drawing used. After proofing, the production printing plate is made. The repetition of this process will be avoided as much as possible

2. Control of ink in the production process

haze is measured by the ratio of transmitted light intensity and total transmitted light intensity whose deviation from the direction of the incident beam is greater than 2.5 degrees. The printing process is mainly to control the viscosity and hue of the ink. Flexographic printing uses ceramic roller for indirect ink supply, gravure printing is immersion direct ink supply, and printing uses the ink scraper to move back and forth to directly supply ink on the plate. Offset printing mostly uses ink roller for indirect ink supply

flexographic printing inks are roughly divided into water-based inks, alcohol soluble inks and UV inks. Gravure printing inks are now mainly ester soluble and alcohol soluble inks represented by the national development and Reform Commission of the Ministry of industry and information technology of the people's Republic of China. Printing inks are typical of UV and anti-counterfeiting inks, and offset printing is mainly UV inks, which are widely used in medium and high-end combined printing

different ink supply methods and different systems of inks make it more difficult to control the ink in the production process of combined printing. Generally, try to use the same system of inks and multiple inkers in one machine to reduce the difficulty of operation and control

3. Requirements for the quality of operators

combined printing line post-processing is the combination of several single printing methods, such as line transfer, cold pressing, die-cutting unit, etc. it puts forward high quality requirements for operators, requiring them to not only know the machine structure and registration device like the palm of their hand, but also understand the four printing processes and post press processing principles thoroughly, and master the operation of equipment and the adjustment of ink hue and viscosity. Generally, the captain with rich work experience must be trained at multiple levels to make all aspects of skills qualified in order to ensure product quality

in a word, with the rapid development of medium and high-end cigarette labels in the direction of integration and soft package, the combined printing technology of connecting line transfer, cold pressing, die cutting and other elements based on flexible printing will be more and more perfect, and will continue to be applied to cigarette package printing technology. The above are some of the author's experiences and experiences. If there is anything inappropriate, please comment and correct it

reprinted from: Youyin