Safety device in a blueprint machine

摘要

A safety device in a blueprint machine contains an air-cooled exposure cylinder through which there flows, from an external blower, cooling air which enters the cylinder at at least one end face and flows into at least one suction line of the blower. In order to specify a reliable and safe overheating protection, there is arranged at the endface entry of the cooling air a measuring sensor of a pressure switch which switches off the blueprint machine when a prescribed minimum underpressure is undershot at the cooling air entry. Consequently, the cooling itself - and not the temperature - is detected as the measured quantity which initiates the overheating protection.