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Can flexographic water-based ink be used for offset printing

Date: Jan 30 2025  From: Star Color   


In the printing industry, the compatibility between ink and printing methods is crucial, as it directly affects the quality and production efficiency of printed materials. Recently, many friends have been asking: Can flexographic water-based ink be used for offset printing? Today, let's delve into this interesting topic together.

Flexographic water-based ink and principles of flexographic printing

Flexographic water-based ink, using water as the main solvent, has outstanding environmental characteristics and is highly favored by the market. In flexographic printing, its transfer process is very distinctive. Firstly, the ink is quantitatively transferred through a mesh roller, and the ink is transferred to a flexible printing plate with elasticity. Then, the printing plate comes into contact with the substrate, and under a certain pressure, the ink is transferred to the surface of the substrate, completing the printing process. This printing method is suitable for various materials such as paper, plastic film, label materials, etc., and is widely used in the field of packaging printing.

The unique principle of offset printing
Offset printing utilizes the principle of oil water incompatibility. The graphic and textual parts on the printing plate are hydrophilic and hydrophobic, while the blank parts are hydrophilic and hydrophobic. First, supply water to the printing plate to form a water film on the blank area, and then supply ink to absorb the ink on the graphic and text parts. Afterwards, the ink is first transferred to the rubber blanket, and finally transferred to the substrate through the rubber blanket. Offset printing has high printing accuracy and is commonly used in the production of printed materials such as books, magazines, posters, etc. that require high printing quality.
Can flexographic water-based ink be used for offset printing

Adaptability from Ink Characteristics

Characteristics of flexographic water-based ink
Viscosity characteristics: The viscosity of flexographic water-based ink is usually between 200-2000mPa · s, which belongs to medium to low viscosity. This is to meet the ink transfer requirements of the mesh roller in flexographic printing, so that the ink can smoothly fill the mesh holes and transfer to the printing plate and substrate.

Drying characteristics: It mainly relies on water evaporation for drying, with a relatively slow drying speed, and is greatly affected by environmental temperature and humidity. In high temperature and low humidity environments, the drying speed will accelerate; On the contrary, in low temperature and high humidity environments, the drying speed slows down significantly.

Requirements for Ink in Offset Printing
Viscosity requirement: The viscosity of offset printing ink is relatively high, generally between 10000-50000mPa · s. Because ink needs to be well transferred between ink rollers during the offset printing process, high viscosity can prevent excessive diffusion of ink on the rollers, ensuring accurate transfer of ink to the printing plate and substrate, and ensuring the clarity and color saturation of the printed product.
Drying characteristics: The drying method of offset printing ink is relatively complex, in addition to infiltration drying, there are also oxidation film drying and other methods. This requires ink to quickly penetrate into the interior of the paper after printing, while rapidly oxidizing the film on the surface of the paper to form a strong ink film.

Challenges brought by differences in characteristics

From the comparison of the above characteristics, it can be seen that there are significant differences in the ink requirements between flexographic water-based ink and offset printing. If flexographic water-based ink is used for offset printing, problems will first arise in the ink transfer process. Low viscosity flexographic water-based ink may not be able to stably transfer between offset ink rollers, leading to ink splashing, uneven ink volume, and other issues that seriously affect printing quality. Secondly, in terms of drying, the slow drying speed and high environmental impact of flexographic water-based ink do not meet the requirements of rapid drying in offset printing, which may lead to problems such as dirtiness and adhesion of printed materials, reducing production efficiency.
Can flexographic water-based ink be used for offset printing

Practical application cases and industry attempts

In actual production, some companies have tried to use flexographic water-based ink for offset printing, but most of them have poor results. For example, a small printing company attempted to use flexographic water-based ink on offset printing machines to print promotional posters in order to reduce costs and improve environmental protection. The frequent occurrence of unstable ink transfer, uneven color distribution, and extremely slow drying speed during the printing process seriously affected the production schedule. In the end, this batch of posters could not be delivered due to quality issues, causing economic losses to the company.

However, there are also some research institutions and ink manufacturers working hard to explore solutions. They attempted to improve the viscosity and drying speed of flexographic water-based ink by adjusting its formula, making it closer to the performance requirements of offset printing ink. However, at present, these improvements are still in the experimental stage and have not fully solved the technical difficulties of using flexographic water-based ink for offset printing.

Although flexographic water-based ink has significant environmental advantages, it cannot be directly used for offset printing based on current technology and processes. The development of the printing industry cannot be separated from technological innovation and breakthroughs. Perhaps in the near future, with the advancement of technology, the compatibility problem between flexographic water-based ink and offset printing can be solved, bringing more environmentally friendly and efficient production methods to the printing industry.