Tuesday, April 30, 2019
A major envelope manufacturer needs to verify the presence of seam gum on bright white envelope wings to assure product quality, reduce scrap and associated costs.
Recent trends in the paper industry have resulted in increased brightness of commercial white paper to 92 bright. Optical brighteners added to white paper causes the paper to fluoresce. Traditional gum verification systems that rely on UV additives in the gum to detect its presence cannot reliably differentiate between the background (92 bright paper) and the gum due to the strong emission of the paper.