Double Sheet Sensors

Double-sheet monitoring is a special application for which through-beam sensorsare ideally designed. In this application originating in the printing industry, an ultrasonic through-beam sensor measures paper or sheet thickness.

Ultrasonic sensors for double-sheet monitoring are suitable for detecting the difference between:

• No sheet, one sheet or double sheet
• Carrier material
• Carrier material with labels

Ultrasonic double-sheet monitoring is used in applications where the difference between carrier materials, labels and individual or double sheets must be detected automatically and at high speed to protect machines or prevent rejection. A complete system consists of an ultrasonic transmitter, an ultrasonic receiver and an evaluation unit, which may be separate or integrated into the receiver. The components are optimally tuned to each other when they ship from the factory and must not be used separately from each other.

Product features:

• Detection of materials from paper (10 g/m²) to cardboard (2000 g/m²) possible
• Thin plastic or metal sheets can also be detected
• TEACH-IN for different materials
• Suitable for use on glossy and transparent materials
• Automatic compensation for slowly changing ambient conditions
• Very high processing speed
• Insensitive to dirt

Typical applications include:

• Use in print machines where ultrasonic double-sheet monitoring protects complex mechanical systems from being damaged by drawing in two sheets or prevents the second sheet from remaining in the machine
• Detecting whether labels have been applied to a carrier material and to count how many labels are applied in labeling machines
• Used in letter opening devices to check that letters have been completely emptied of all contents
• Used in receipt counting machines where ultrasonic double-sheet monitoring is used to ensure that bank receipts are counted correctly
• Used in packaging machines to detect adhesive points where two sheets will be joined together and machine speed permits
• Detection of air, individual and double sheets in paper processing machines