Definition
The Printing Manual Spreader Wheel is a specialized hand tool used for quality control in the printing industry, primarily used to prepare uniform and quantitative ink or coating color samples on substrates. It simulates the printing process through mechanical rolling, helping operators quickly evaluate key parameters such as color performance, masking force, and adhesion, providing an experimental basis for printing process adjustment and material selection.
Principle
The instrument works on the principle of mechanical rolling transfer. To operate it, the dosing ink is placed on a stationary substrate and rolled at a constant speed at constant pressure by manually driving the color spreader. The special material and structure design of the color spreader surface make the ink evenly stretched during the rolling process, forming a continuous ink film with controllable thickness. This process simulates the transfer behavior of the printing machine roller, and the ink film thickness T can be approximately expressed as: T = V / (w × L), where V represents the ink volume, w is the color spread width, and L is the rolling unfolding length.
Measurement method
Clean the color roller and substrate before use. Take a standard amount of ink and place it at the starting end of the substrate, and push the color spreader wheel to roll in one direction at a stable speed to ensure that the wheel body is in full contact with the substrate. After unfolding, the color sample is cured in a standard environment and then quantified by visual colorimetry, density meter, or colorimeter. Parameters such as ambient temperature and humidity, substrate type, and curing time should be recorded during measurement to ensure comparability of results.
Influencing factors
The color development effect is affected by many factors. The stability of the operating angle and speed directly affects the uniformity of the ink film. Ambient temperature and humidity will affect ink leveling and drying speed. The physical characteristics of the surface energy and ink absorption of the substrate determine the adhesion state of the ink layer. The hardness and surface texture of the color roller also play a role in the ink transfer efficiency. In addition, the rheological properties of the ink itself, such as viscosity and thixotropy, are also key variables.
Applications
The tool is widely used in printing shops, ink manufacturing plants, and quality inspection laboratories. It is mainly used in ink color proofing, coverage force comparison test, preliminary evaluation of printed wear resistance, spot color verification and other scenarios. In the fields of packaging printing, publication printing and special printing, it can be used as a quick pre-inspection method before the printing machine goes online, and assists in the formulation of printing process parameters.
Selection considerations
When selecting, it is necessary to pay attention to the width specification of the color exhibition wheel, which should match the width of the commonly used printed product; The material of the wheel body should consider solvent resistance and wear resistance; The pressure adjustment mechanism should ensure pressure repeatability; The design of the grip structure affects the comfort and stability of the operation. At the same time, it is necessary to select the color roll with corresponding surface characteristics according to the type of commonly used ink, and consider the compatibility of the supporting substrate fixture. The selection should be based on the typical substrate, ink system and testing standards of the actual application scenario.