Definition
Flexographic ink spreader wheel is a laboratory simulation tool used to evaluate the color performance and printability of flexographic inks. It simulates the key conditions of the actual printing process to form a uniform ink film layer on the standard substrate, providing standardized samples for subsequent color measurement and performance testing. This instrument plays an important role in ink R&D and quality control in packaging printing, film printing and other related industries.
Principle
The core working principle of flexographic ink spreader wheel is to simulate the anilox roller ink transfer process of flexographic printing. The instrument typically consists of a precisely machined metal spreader wheel and a matching scraper system. The surface of the color spreader wheel has a specific mesh cavity structure, and its parameters such as the number of lines and volume can refer to the actual printing anilox roller specifications. During operation, the quantitative ink is applied to the surface of the rotating color spreader, and the scraper scrapes off the excess ink, so that the ink is just filled in the mesh cavity. Subsequently, the color roller transfers the ink in the mesh cavity to the printing substrate, forming a controllable and uniform ink film. This process realizes the controllable preparation from liquid ink to solid ink film, and the transfer amount can be estimated by the ink characteristics and the geometric volume of the mesh cavity, and the relevant ink transfer amount model can be simplified as:
V ≈ K × C
Where V represents the ink transfer volume per unit area, C represents the mesh volume of the anilox roller, and K is a coefficient related to ink rheological characteristics and transfer efficiency.
Measurement and evaluation methods
After preparing the standard color spreading spline using a flexographic ink color display wheel, systematic measurement is required. Color evaluation typically uses a spectrophotometer that measures the chromaticity values L*, a*, b*, and chromatic aberration ΔE to quantify color intensity and consistency. The ink layer thickness can be measured with a micrometer or a special film thickness gauge. In addition, the color spline needs to be tested for adhesion, abrasion resistance, light fastness, etc., all of which need to be performed under standard temperature and humidity environments. The entire evaluation process must strictly refer to relevant industry standards, such as the ISO 2834 series of standards for the preparation of printed products for prepress tests, to ensure data comparability and reproducibility.
Influencing factors
The color development effect is affected by multiple factors. In terms of instrument parameters, the number of threads, depth, shape and engraving angle of the color exhibition wheel determine the bearing and release characteristics of the ink. Under operating conditions, the rotation speed of the color spreader and the pressure and angle of the scraper will affect the uniformity of the ink film. The rheological properties of the ink itself, such as viscosity, thixotropy, and drying speed, are key variables that directly affect the filling and transfer behavior of the ink. Ambient temperature and humidity can affect the fluidity and drying process of the ink. Finally, the surface energy, roughness and ink absorption of the substrate can also lead to differences in the color and state of the final ink film.
Applications
Flexographic ink spreader wheels are mainly used in technical fields related to flexographic printing. In the ink manufacturing industry, it is used for color development, strength assessment, and printability testing of new ink formulations. In printing enterprises, it is used for quality consistency inspection of incoming inks. In the packaging material supply chain, brands or packaging processing plants can use this tool to formulate color standards and sign samples. In addition, it is also an important tool for scientific research institutions to study ink rheology, color science and printing transfer mechanisms.
Selection considerations
Choosing the right flexographic ink color spreader requires comprehensive consideration. First, it is necessary to clarify the type of ink to be tested and the corresponding range of substrates, such as paper, plastic film or metal foil. The core parameter is the screen specification of the color roller, which should ensure that its line number and volume range can cover the daily simulation of printing conditions. The manufacturing accuracy of the instrument, the durability of the material, and the stability of the squeegee system are fundamental to ensuring reproducible results. Ease of operation, such as the ease of cleaning and the versatility of accessories, also affect daily work efficiency. Finally, it is necessary to confirm the technical standards followed by the instrument design to ensure the recognition of its output data in the industry.