In the production process of printed labels, the registration accuracy directly affects the quality and appearance of the labels, and is related to the market image of the product. The following are several key registration accuracy control methods.
First, accurate debugging and maintenance of the equipment is the basis. Before printing, the various components of the printing press should be carefully inspected and calibrated. For example, ensure that the installation position of the plate roller is accurate, and the concentricity and cylindricity of the plate roller must meet the standards to avoid displacement of the pattern during printing due to plate roller deviation. At the same time, adjust the printing pressure. Excessive or insufficient pressure will affect the amount of ink transfer and the degree of paper deformation, thereby destroying the registration accuracy. Regularly maintain the transmission system of the printing press to ensure that the wear of transmission parts such as gears and chains is within a reasonable range, so that the transmission ratio between each plate roller is stable and accurate. For example, by installing a high-precision encoder to monitor and adjust the speed of the plate roller in real time, ensure the synchronous operation of different color plate rollers, and effectively reduce the registration error.
Secondly, adopt advanced registration detection and control systems. Most modern printing presses are equipped with high-precision registration detection devices, such as photoelectric eye detection systems. It can monitor the position of the printed pattern in real time and feed back the signal to the control system. Once the registration deviation is found, the control system will quickly adjust the position of the plate roller or the printing speed. For example, in the multi-color printing process, the photoelectric eye can accurately detect the deviation value of each color pattern relative to the reference point. The control system calculates the adjustment amount based on these data, and drives the plate roller to make fine adjustments in the horizontal or vertical direction through the motor, so that the subsequent printed pattern can be accurately registered, and the deviation is controlled within a very small range, generally within ±0.1 mm.
In addition, the printing materials should be effectively managed and pre-processed. The quality and performance of the paper or film materials used in printed labels have a significant impact on the registration accuracy. The thickness uniformity, flatness and expansion rate of the material need to be strictly controlled. Before printing, the material can be pre-processed, such as humidifying the paper to stabilize its moisture content and reduce the expansion and contraction deformation of the paper caused by changes in environmental humidity. For materials such as plastic films, products with stable quality, suitable tensile strength and expansion rate should be selected, and the tension should be reasonably controlled during the printing process. The tension sensor monitors and adjusts the tension of the material in real time to avoid excessive or insufficient tension that causes the material to stretch or relax, thereby ensuring that each color pattern can be accurately overprinted during the printing process.
Finally, the professional quality and experience of the operator are also crucial. Skilled operators can promptly detect potential overprinting problems during the printing process and take effective measures to deal with them. They can reasonably set printing parameters such as ink viscosity and drying speed according to different printing tasks and material characteristics to avoid overprinting errors caused by poor ink drying. At the same time, operators should focus on summarizing experience in their daily work and form a set of effective responses to common overprinting problems. For example, when encountering slight overprinting deviations, they can quickly determine whether it is an equipment problem or a material problem, and make targeted adjustments to ensure that the overprinting accuracy of printed labels is always at a high level to meet the requirements of high-quality printing.
