Printing unit of a printing press, comprising at least two frame parts, the position of which relative to one another can be changed

A printing unit of a printing press comprising:

• first and second interacting frame parts, the positions of which, relative to one another, can be changed, and wherein the first and second interacting frame parts can be placed contacting one another along a shared joining surface in a first operating position and can be moved away from one another along an adjustment path to a second operating position;
• an intermediate space, having an intermediate space distance, formed between the first and second interacting frame parts, when the first and second frame parts are moved away from one another in the printing unit and along the adjustment path to the second operating position, and which intermediate space is delimited in part by the first and second frame parts;
• means for moving at least one frame part with respect to the other frame part along the adjustment path
• at least one sensor adapted to monitor the intermediate space between the first and second frame part, the at least one sensor having at least one of a directional characteristic effective along the joining surface and a sensing zone effective along the joining surface, a first field width of a first angular field of the at least one of the directional characteristic and of the sensing zone, which first field width is oriented parallel to the adjustment path of the movable frame part, being smaller than a respective field width of a second angular field or of a third angular field of the at least one of the directional characteristic and the sensing zone, the second field width of the second angular field of the at least one of the directional characteristic and the sensing zone being oriented in an axial direction of at least one printing couple cylinder mounted in the movable frame part and the third field width of the third angular field of the at least one of the directional characteristic and the sensing zone, being oriented in a direction of a height of the movable frame part;
• and
• a control unit connected to the at least one sensor to control the means for moving the at least one frame part, which control unit does not evaluate a signal received from the at least one sensor, when a predefined distance, over which the first and second frame parts have been moved toward one another, is reached, the predefined distance at which the control unit does not evaluate a signal received from the at least one sensor being greater than the first field width and less than the intermediate space.