Abstract: In an apparatus on a spinning preparation machine, for example, a flat card, draw frame or the like, for monitoring at least one sliver, having two rotating rollers that form a roller nip through which at least one sliver passes, an optical monitoring arrangement (sensor) that monitors the presence of the sliver is provided in the vicinity of the rollers. To permit a reliable and trouble-free monitoring of sliver breakage in a structurally simple manner, the sensor arrangement is arranged in the region between the shared tangents to the peripheral surfaces of the rollers, the tangents being arranged perpendicularly to the running direction of the fiber, and the optical path of the sensor runs parallel to the axles of the rollers.

Abstract: In an apparatus on a spinning preparation machine, for example, a flat card, roller card, draw frame or the like, for monitoring fiber material, having at least one rotating roller that delivers fiber material, and a monitoring arrangement device that detects undesirable accumulations (build-up) of fiber material and emits an electrical signal is present. To permit immediate detection of undesirable accumulations of material in a structurally simple manner, the monitoring arrangement comprises a non-contact sensor arrangement (sensor), which is capable of detecting undesirable accumulations of fiber material.