Newspapers and magazines produced in printing works must be counted as they travel on fast moving conveyors.
Newspapers and magazines produced in printing works must be counted as they travel on fast moving conveyors. Here the printed products are transported in an offset, i.e. overlapped arrangement. Currently mechanical switches are used for this task, however there are subject to wear and require maintenance. It is also not possible to exclude incorrect counting or the failure to count.
For counting newspapers and magazines in the printing press, the offset stack counter DMH is used in many cases, predominantly with a scanning range of 110 mm. The height profile acquired by the sensor is evaluated based on the step reductions in height caused by the layers of newspapers. Here the step changes in height can leave the measurement field in the direction away from the sensor (mode 1) and in the direction toward the sensor (mode 3). At the point when a step change in height from one newspaper to the next, a so-called offset stack, is detected, the offset stack counter DMH outputs the corresponding count pulse. Newspapers and magazines of varying thickness can be correctly counted after one-off adjustment.
Using this non-contact system, the maintenance required on mechanical switches due to wear is avoided. The error rates when counting are also significantly reduced. Even height fluctuations on the conveyor or interrupted flows of offset stacks do not affect the measured result.