Author: Ping Baoping
In recent years, with the application of CDI technology in the flexo industry, flexo products have got rid of the image of poor printing quality and fineness in the early stage, and have gradually impacted on the middle and high-end markets. Nowadays, many flexo manufacturers can produce exquisite products that are compared with traditional offset printing and gravure printing. The application range of the product has also been promoted from the early low-grade packaging bags, carton corrugated paper, etc. to cigarette labels, wine labels, high-fidelity packaging, films, fine corrugated paper, milk bags and other fields. But simply having a digital flexographic version does not mean having high-precision flexo quality. Many manufacturers report that even if high-quality digital flexographic plates are used, the product fineness has not achieved the desired results.
The effect of substrates on product fineness
Various types of coated paper with a basis weight below 90g / m2, after long-distance transportation and long-term stacking, the moisture content will greatly change with the surrounding environment. In addition, the length of the paper path of the flexo printing machine must be dried by a multi-color unit. If it is thin paper, it will deform many times and the deformation direction is inconsistent, which has a great impact on the quality of the product with multi-color overprint. Therefore, the paper supplier must strictly control the moisture content of the paper factory, shorten the transportation cycle as much as possible, and avoid exposure to sunlight during the transportation or staying in the rainy weather for too long. These measures are the prerequisites for controlling the fineness of the product during the printing process.
The effect of ink on product fineness
Fine prints usually need to meet the following quality requirements:
(1) The ground is flat and delicate, with neat surroundings and no ghosting.
(2) The dots are clear, the deformation is small, and the layers are clear.
(3) If there are thin lines and small text, clear lines are required, and the text is exquisite and not confusing.
(4) Multi-color overprinting requires accurate overprinting, no leakage, and no too many overlapping borders.
Under the premise that the printing pressure has been adjusted in place, the ink performance is adjusted to maintain a stable viscosity and good printability, so that the printed matter can meet the above four requirements.
Generally, the viscosity of ink used in field products is 45 '～ 60' (coating 4 # cup), and the ink leveling and hiding power of this viscosity range are both. The ink has good hiding power and is solid on the ground; the ink has good leveling property and is fine and shiny on the ground. The viscosity of the ink used in the network cable product is 30'-40 '(coating 4 # cup), the ink transfer performance of this viscosity range is good, the reproducibility of the dot is strong, the printed product has clear dots, small deformation, and is not easy to paste , Dirty version. Multi-color overprinted products are designed to minimize trapping parameters under the premise of overprinting, and the printing color sequence is reasonably arranged to ensure that the ink color of the latter color printing covers the previous color trapping.
The effect of printing process on product fineness.
Printing process settings: such as trapping parameter settings, printing color sequence arranged before and after, embossing, stamping is not set for the post-process mark, etc.
Compared with offset printing and gravure printing, the overprinting accuracy of the flexo printing machine is poor. If the printed product must go through the subsequent processes such as bronzing and embossing, and can not be connected with the flexo printing machine, marking in advance on the printing plate is a prerequisite for ensuring the accuracy of the subsequent process and also ensuring whether the product packaging is beautiful The essential. Whether the product printing is suitable and perfect after packaging is an important aspect reflecting the fineness of the product.
In short, the improvement of the fineness of flexo products is not only directly related to printing equipment and plate production, but also has a closer relationship with the selection of substrates, ink adjustment, printing process and printing operation level in the printing process.
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Ningbo Fineweather International Trade Co., Ltd. , https://www.fwsbag.com