Static buildup is directly related to the moisture content of the paper and the relative humidity of the pressroom. Toner-based digital presses have a high-temperature fuser roller that melts or softens the toner, which adheres it to the paper and also removes a significant amount of moisture from the paper. This results in the paper being more prone to static buildup. The recommended relative humidity of the pressroom is 45%-55%. Relative humidity around or below 30% RH will contribute to static buildup.
One inexpensive method of reducing static electricity in your paper is to tape a dryer sheet to the back of each paper drawer. You want to make sure it won't get pulled in as well, so ensure the dryer sheet is taped and/or properly secured in the back of the drawer. Consult your digital press representative for their recommendations.