The carton is printed and discolored, what should I do?
pull out,waste bin,trash can Foshan Gruwill Hardware Products Co., Ltd. , https://www.zsgruwill.com
When operating a carton flexo ink printing machine, it's common for the color of the printed material to change during the process. This can be frustrating, especially when operators lack the experience or tools to predict and address such issues promptly. As a result, many defective prints may end up being produced. In this article, "Packaging Zone" shares several practical solutions that industry professionals can apply to minimize color variations and improve print quality.
First, it's essential to review the design of your printed materials. For instance, if a large area with heavy ink coverage is placed in a position that’s hard to control, it can lead to uneven ink distribution and color inconsistencies. To avoid this, try positioning such areas in the gripper zone, where the paper is better controlled. This helps maintain consistent ink transfer and reduces the risk of color shifts. If after making these adjustments the problem persists, it's important to contact the manufacturer for further inspection and repair.
Next, after ruling out film-related issues, check the ink delivery system. A simple but effective method is to clean the ink path thoroughly using car wash water (you can add some detergent if needed). Once cleaned, inspect the ink path for any white crystalline deposits. These particles can cause localized color changes, especially in certain areas of the print. If no crystals are found, restart the press, apply ink to all the ink rollers, and then close the plate and water rollers. Check the pressure settings and adjust them if necessary to ensure optimal performance.
During the printing process, it's recommended to use high-quality coated paper to reduce the impact of paper quality on color consistency. For thin paper, keep the air volume as low as possible, while for thicker paper, adjust it appropriately. If color changes occur, don’t immediately assume it's a machine issue. Instead, start by checking external factors like the printing plate. Use a magnifying glass to examine the dots on the plate and look for any deformation. Also, verify the film to rule out any issues that may have occurred during the exposure process.
Another important step is to evaluate the condition of the paper feed system. This includes adjusting the paper wind, ensuring the paper is flat at the front gauge, checking the interaction between the paper and the pressure plate, and verifying the conveyor belt operation. After confirming that the ink path is working properly, move on to the water system. Adjust the pressure between the plate water roller, metering roller, water bucket roller, and water channeling roller. Pay special attention to the intermediate roller and avoid using it if possible.
If the color issue still remains, consider checking the impression cylinder (teeth) for dirt or wear. Clean the rubber pads and the teeth thoroughly, and if possible, remove the spring for a deeper clean. Some operators mistakenly only clean the pads without addressing the teeth, which can lead to poor impressions and color problems. Inspect the teeth for any dead spots and use a high-efficiency rust remover like WD-40 to clean them. Apply grease to the teeth and shafts to ensure smooth operation.
Finally, check the condition of the rubber blanket. The thickness should be around 35 wire, and it's best to use a brand-name aluminum strip. Ensure the blanket is new and re-tighten it after a period of use. Proper maintenance of all components is key to achieving consistent and high-quality prints. By following these steps, you can significantly reduce the occurrence of color variation and improve overall production efficiency.