A cleaning device serves for cleaning sensing or sensor rollers which are mutually biased towards each other and between which travels a fiber sliver. Roll cleaning is effected by means of a scraper blade which, in accordance with the invention, is moved intermittently into a scraping position and away therefrom. This provides the advantages of reduced wear on the scraper blade provided at the cleaning device and also reduced wear on the peripheral surface of the associated sensing or sensor roller which is to be cleaned.