InterTechEliminating Banding In Inkjet Output

Danny Hall, Global Graphics

Ellerhold Aktiengesellschaft was facing quality issues on its large-format posters, also known as mega lights or classic billboard posters, the most popular indoor and outdoor advertising medium in Germany. The firm’s printheads caused visible bands, often on large areas of flat color. To stay relevant in a highly competitive environment, Ellerhold Aktiengesellschaft needed a reliable solution and turned to Global Graphics’ PrintFlat technology to start a calibration workflow for its printing device to produce uniform output covering the entire poster width. Now the company follows a simplified process where staff upload scans to Global Graphics online inkjet press calibration service. Automatically the company receives corrected calibrations, allowing the firm to have print runs with the best quality.

PrintFlat software corrects banding and non-uniformity in inkjet output that happens because of manufacturing variations within and between printheads or after they are replaced in the field. Banding, also known as the inkjet smile or frown, is chronic on areas of flat tints, such as the blues of a sky. This makes the print output unacceptable to press vendors and their customers, leading to financial losses. That’s because a significant percent of jobs, depending of the market, cannot be printed digitally because of banding issues.

PrintFlat creates customized calibration based on press measurement, which is installed into the ScreenPro screening engine. This directly corrects the presses. By adjusting the density within, ScreenPro, PrintFlat creates uniformity across a print bar. Also by automating the process, it allows for closed-loop correction, meaning there is no effect on jetting stability or head lifetime, ink pressure, and timing/drop speed variation.

Companies see immediate results. Businesses can have very fine granularity because the software addresses every nozzle separately on any head while making previously unacceptable print heads acceptable. It saves the time and cost of building and maintaining a press. PrintFlat can also be accessed via an online portal and businesses can upload a scan of the print bar to a website via a user account. PrintFlat creates corrections that can be applied directly to the presses.

To correct undesired effects people generally have had to tweak the head voltages, but that is a hands-on and time consuming task that doesn’t easily lead to the desired results. The main advantages from PrintFlat are that it is quick to apply, saves money, and can be used in any workflow.

This is the second InterTech Technology Award in successive years for Global Graphics. Last year the company received an award for SceenPro screening engine that can mask imperfections in output from high-speed inkjet presses.