Common Quality Issues with Printing Rollers

Common Quality Issues with Printing Rollers

During the printing process, common problems with printing rollers include scratches, impacts, collisions, roller depressions, and chrome peeling.

Scratches

Scratches refer to visible lines on the entire surface of the plate roller, often appearing after printing. These lines can be clear and distinct, and severe cases may expose the copper, affecting print quality. The primary cause of scratches is improper printing operation. Common misconceptions in our current operating methods include manually adjusting the blade pressure instead of using the blade cylinder to regulate it. Additionally, when facing print quality issues related to inadequate scraping, it's often narrowly interpreted as insufficient blade pressure. Some attempt to solve the problem by directly shutting off the ink blade's swinging stroke. However, these methods increase friction between the ink blade and the plate roller. Under high-speed printing conditions, direct, harsh contact between the ink blade and the plate roller occurs, lacking the necessary elasticity. This results in excessive ink blade pressure, increased friction, rapid blade wear, flipping, plate roller damage, and a shallower halftone and chrome layer. Ultimately, this leads to visible scraping lines on the plate, causing damage to the plate roller and ink blade.

Solution: When assembling the ink blade, pay attention to the parallelism of the three points and a line. Train employees to master the correct operation of the ink blade and understand how to address printing quality issues through proper adjustment.

Impacts and Collisions

During the transportation of plate rollers or in the printing process, local injuries can occur due to foreign objects colliding with the roller body, affecting the information in the graphic area.

The main reasons for impacts and collisions are inadequate protective measures during roller handling or excessive movement, leading to deviations in the on-machine operation program. This is often due to the arbitrary nature of employees when disassembling and assembling plate rollers, the lack of specialized tools, and insufficient training for operators. In the printing workshop, improper operation and procedural issues during the use of plate rollers can result in collisions and impacts, particularly among new or less conscientious employees.

Recommendation: Establish appropriate and correct standards and operating procedures for the entry and exit of plate rollers. Train employees in the correct operation and use of plate rollers and create suitable specialized tools, such as plate transport carts and plate-loading carts. More importantly, focus on training in quality and responsibility awareness.

Roller Depressions

Roller depressions refer to the occurrence of a depression in a specific area of the roller during the pre-production or production process, preventing complete printing of the graphic information.

The main cause of roller depressions lies with the roller supplier. While such issues are relatively rare among reputable roller suppliers, one phenomenon worth noting is missed engraving.

Recommendation: In addition to routine checks, it is essential to conduct detailed inspections of the roller body for each batch of rollers. When cleaning the plate roller, pay attention to the sensation when hands come into contact with the roller. Depressions are noticeably different from the normal roller body, and this requires careful observation to identify. Additionally, after completing a full sample, carefully inspect it to discover any of the aforementioned problems.

Chrome Peeling

Chrome peeling occurs when the chrome layer on the roller body peels off intermittently or continuously, directly affecting the ability to print graphic information and resulting in defects.

The main reasons for chrome peeling are inadequate chrome layer thickness and treatment effects on the plate roller. Furthermore, poor storage conditions, improper operation, maintenance, and cleaning during the later stages of printing can contribute to chrome peeling. Many flexible packaging companies are considering cost-saving measures, and plate-making factories are no exception. When choosing plate roller suppliers, it is crucial not only to consider price but also to prioritize quality. Some plate-making factories offer lower prices per square meter, claiming to be more cost-effective. While some enterprises may have cost savings in technology and management and can compete at lower prices while maintaining quality, this is the exception rather than the rule. Cheap plate rollers may have deviations in chrome layer treatment and thickness. Overall gloss, halftone quality, and the quality of the two ends of the plug may also deviate. Therefore, selecting high-quality suppliers is crucial to ensuring product and plate roller quality and minimizing losses.