Monitoring apparatus for the sheet feed to a sheet-processing machine, and method of monitoring the sheet stream structure/the sheet stream

A method of monitoring a sheet stream structure or a sheet stream being transferred into a sheet-processing machine, which comprises:

• transporting a stream of sheets across a back-pressure element and towards a sheet-processing machine;
• displacing at least one sensing element in a direction towards the back-pressure element over which the stream of sheets is guided in the form of an overlapping sheet stream or a sheet stream having individual sheets;
• detecting, with the sensing element set against the sheet stream, the sheet stream as it is transferred into the sheet-processing machine;
• and
• thereby displacing the sensing element with respect to the sheet stream in dependence on an instantaneous sheet stream thickness such that a pressing force with which the sensing element is pressed against the sheet stream is maintained within a predefined range.

A method of monitoring a sheet stream structure or a sheet stream being transferred into a sheet-processing machine, which comprises:

• transporting a stream of sheets across a back-pressure element and towards a sheet-processing machine;
• displacing at least one sensing element in a direction towards the back-pressure element over which the stream of sheets is guided in the form of an overlapping sheet stream or a sheet stream having individual sheets;
• detecting a sheet stream structure with the sensing element in contact at a start of the sheet transfer;
• determining a height profile of the sheet stream from information obtained in the sheet stream detecting step;
• setting the sensing element away from the sheet stream and, during a further transfer of the sheet stream, continuously displacing the sensing element in the direction of the sheet stream and in the opposite direction such that a clear spacing between the sensing element and the sheet stream is substantially constant;
• and
• if a fault in the sheet stream is detected, outputting a fault message.