Definition
Ink decolorization testing machine is a special testing equipment used to evaluate the abrasion resistance of inks on the surface of printed products. It quantitatively measures the ability of ink layers to resist peeling or transfer by simulating friction that may occur during actual use or transportation. The instrument has a wide range of applications in the printing and packaging, label manufacturing, publishing and consumer goods industries, and its test results are often used as an important basis for product quality control and compliance verification.
Principle
The ink decolorization testing machine is designed based on the principle of mechanical friction. Instruments are typically equipped with a friction head that applies a defined pressure that wraps around a standard friction medium such as white test paper or a specific fabric. During the test, the friction head moves back and forth on the surface of the specimen with a fixed stroke and frequency, so that the ink layer is subjected to uniform friction. The wear resistance of the ink can be evaluated before and after friction by comparing the color change of the specimen or the amount of ink transferred to the friction medium. The basic force relationship can be expressed as: F = μ × N, where F is the friction force, μ is the friction coefficient, and N is the applied positive pressure. The instrument ensures consistency in test conditions by precisely controlling N, friction velocity, and stroke.
Measurement method
Standard measurement processes typically follow relevant industry specifications (e.g., GB/T 7706, ASTM D5264, etc.). First, the printed specimen is fixed on the testing machine platform. The clean friction media is then installed on the friction head, and the load weight, number of frictions and movement speed are set according to the standard. After starting the instrument, the friction head automatically completes the friction test according to the set parameters. After the test, the specimen is removed from the friction medium, and the color difference between the friction area and the non-friction area is compared using a colorimeter or grayscale card, or the degree of contamination of the friction medium is assessed. Some methods calculate the decolorization rate as follows: ΔE = √((L₁ - L₂)² + (a₁ - a₂)² + (b₁ - b₂)²), where ΔE is the color difference value and L, a, and b represent the coordinates of the color space.
Influencing factors
Test results are influenced by multiple factors. In terms of instrument parameters, the applied pressure, friction frequency, friction stroke and friction head shape will directly affect the friction strength. Environmental conditions such as temperature and humidity can alter the physical state of the ink or substrate. The characteristics of the specimen include ink type, dryness, coating thickness and surface energy of the substrate, etc., which determine the adhesion and wear resistance of the ink. Additionally, the choice of friction medium (e.g., paper weight, fabric texture) can also affect ink transfer effectiveness. Therefore, standard tests need to strictly control the above variables to ensure data comparability and repeatability.
Applications
This equipment is mainly used for quality control in the printing and packaging industry, such as testing the abrasion resistance of printed materials such as food packaging, cosmetic boxes, and book covers, to ensure that they maintain the integrity of graphics and texts in circulation. In the labeling industry, it is used to evaluate the durability of self-adhesive labels and shipping labels. Printing patterns in consumer goods such as toys and stationery are also often subject to decolorization tests to meet safety and durability requirements. In addition, test data can be used during the R&D phase to assist in optimizing ink formulations, printing processes, or surface treatment options.
Selection considerations
Choosing a suitable ink decolorization testing machine requires comprehensive consideration of testing needs and technical parameters. First of all, the standard system to be followed should be clarified to ensure that the instrument meets the requirements of the corresponding specification for load range, friction stroke and control accuracy. Secondly, according to the size and shape of common specimens, choose the appropriate specimen fixture. The operation interface of the instrument should be intuitive and easy to use, and the data logging function should facilitate the traceability of results. Durability and ease of maintenance are also key factors for long-term use, and it is recommended to pay attention to the material and design of the core components. Finally, consider whether multi-function expansions, such as integrated chromatic aberration measurement modules, are needed to improve testing efficiency and integration.