Let’s start with the basics. A rotary screen is exactly what it sounds like, a steel screen in a cylindrical form that is glued to aluminum rings on each end called end rings. Once the screen is assembled, emulsion is applied to the entire screen and a film positive is placed around the screen. The screen is exposed to UV light and then washed out to remove the emulsion from the imaged areas. Once the screen is exposed, it is placed in the press where ink is pumped directly in to the screen. As it rotates, ink is forced out of the exposed area of the screen with a “squeegee” and transferred to the material you are printing.

Now that we understand the basics, we can move on to why one would use a rotary screen. Two of the most common uses for rotary screen printing are for additional opacity and the need to print bold small type that can be easily read on any colored container. Therefore, a majority of the time the substrate used is a clear material to give the “no label” appearance.

Let’s start with opacity. Because we are pushing ink through a screen onto the substrate, we have the ability to put down a variable amount of ink depending on the mesh count and open area. The mesh count is the number of openings per linear inch and the open area is the total surface area of the holes in the screen as a percentage of the total surface area. By varying either factor, you are able to adjust the ink laydown from a very heavy coat (3 – 10.5 mils) to a light coat (.24 mils). However, keep in mind a light coat of rotary screen is still 4 times more ink coverage than your heaviest anilox when printing UV flexo. A majority of the time a rotary screen white ink is placed behind 4-cp images to allow them to “pop” and give a clean, crisp look.

The second most common use for rotary screens is the printing of very small fine type (4 pt. Serif) with legibility being of the greatest importance. With the “no label” look being so popular in today’s market, the only way to print on a clear label with readable type is to use rotary screens. On today’s busy store shelves, with the many different colors representing your competition, you want your product to stand out and be clearly recognizable by the consumer.

To learn more about printing rotary screen’s and how ROI can help you with your label applications, please give your ROI Sales Representative a call today, or you can reach me at 410.576.1111 ext. 103. In addition, we have placed on our website (www.roilabels.com/whatsnew ) more information and screen specifications for your review.

Start the New Year off with a bang and give us a call to discuss how you can increase your shelf presence and improve your market share with rotary screen printing. Happy New Year!

Tim D. Roberts