We can help you identify the cause and mitigate these print defects
There are several print defects that show as lines across your finished printed products. This defect can be the result of various print issues. Understanding the cause will enable you to get your print back on track quickly, avoiding unnecessary print rejects and downtime.
These print issues include:
Flute lines showing:
Excessive print pressure creates flute lines, also known as Wash Boarding. Contaminated anilox rollers often lead to this problem, as operators increase the pressure to try and rectify the issue.
White line(s) across your print:
Using a ‘water-only’ wash-up cycle leads to dried ink residue forming across the metal doctor blades, which contaminates the anilox roller. Water is unable to clean and remove dried ink, which over time, results in a build-up of ink to form. This issue plugs the anilox cells with dried ink, resulting in a reduced amount of ink transferring to the stereo.
This type of print defect is frequently experienced. However, the root cause is often not identified until significant damage is caused to the anilox roller. When cleaning down your anilox rollers, it is essential that at the end of a print run and working shift you check to ensure the doctor blades are not left in situ against the anilox rollers.
When doctor blades are left against the anilox roller, any ink will dry and cause the doctor blade to become stuck to the anilox.
If this is left unnoticed or is a regular occurrence, a horizontal score line will appear across the width of the anilox roller. This will mirror onto the printed product, resulting in print rejects.
This is when too much ink is delivered to the printing plate, resulting in the image filling in or ‘Dot Gain’ happening. There are a several causes of dot gain, but the typical reasons are:
- Printing pressure is too high
- Incorrect ink viscosity
- Too much anilox cell volume
- Doctor blade transferring too much ink
- Impression or printing plate cylinder is dirty
The possible causes can be checked to identify what is causing the issue of dot gain. However, with regular anilox audits and the correct care and maintenance in place, these issues can be avoided.
These print issues will have serious impact on your print quality, especially if you are printing a fine image or a customer’s branded logo. Dot gain will make the image or logo look ‘fuzzy’ or darker than it should be. This can have serious impact on print rejects.
Other critical components can effect print quality:
Ink viscosity needs to remain constant and correct for the job you are running. In simple terms you don’t want a thick treacle type consistency for your ink, or a very liquid consistency. Either will cause issues with the way the ink acts and relays to the printed substrate and your finish print.
If doctor blades are either the incorrect ones for the press and print job, or been installed incorrectly, or damaged, the transfer of ink will be affected. This can lead to too much ink being transferred from the anilox roller to the plate. Not only will this effect your print and result in print rejects, it will waste your expensive inks. A cost your business certainly wants to avoid.
Ensure you have the correct components to suit your print quality needs
There is a need to ensure you have the correct anilox rollers for the type of print you are using. Anilox rollers come with various cell configurations. The angle and depth of the cells within an anilox roller will have an impact on your print. It is important that you choose the right anilox rollers for your print requirements, to maintain the best quality print.
You can see that there are a number of variables that need to be reviewed and monitored regularly to avoid white line print defects.
It is crucial that your anilox rollers have the correct cell configuration for your print requirements. Anilox rollers also need to be kept in top condition to avoid contamination and incorrect transfer of ink being applied.
Doctor blades are too a vital component in the flexographic print process and should be maintained and changed immediately if they become damaged.
These various issues can impede your print quality. Print Tech Solutions are here to help you minimise your print rejects and production downtime. We provide safe and effective cleaning solutions that have been formulated specifically for the anilox rollers in the flexographic process. With our wealth of experience and expertise we can also support your print operators with technical support and guidance to aid you in maintaining optimum print for your business.
We offer technical support to monitor and maintain your anilox rollers.
Print Tech Solutions offers comprehensive care and maintenance packages that not only ensure consistent high-quality print but also empower your print operators. With the correct training, your print operators will become better equipped in how to monitor the condition of anilox rollers and action to take to reduce and prevent print defects. Our comprehensive training programs will help to achieve these skills.
If you are suffering from print issues or would benefit from additional resources to support you maintain your anilox rollers in top condition, contact our team now.
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