Method and device for monitoring an access point leading into a safety zone of a roll winder or unwinder, and printing press

In some examples, an access point that leads into a safety zone of a roll unwinder or winder is monitored by a monitoring sensor system. The monitoring sensor system includes two scanners having respective measuring beams that pass over an angular region situated in the same plane extending in an opening. The access point is monitored in a pattern of multiple protection fields having various sizes and/or shapes. Multiple ones of the protection fields are encompassed by a next-larger and/or next-wider protection field, entirely or at least viewed in the width and toward the top. The scan images of the two scanners are checked for a breach of the relevant protection fields in differing, adjoining, or overlapping partial regions of the plane. Information about the permissibility of a determined protection field breach is derived by evaluation of breach patterns of breached protection fields obtained in the two partial regions.