A conveyor device for conveying flat articles on edge, for example as part of a postal sorting machine, includes a back belt and a front belt that define a first nip zone for conveying the flat articles along a first path, a conveying strip provided with a first slide plate supporting the flat articles and mounted to move between a working position in which it is situated adjacent to the first nip zone, the first slide plate being aligned with the nip zone, and a retracted position, in which it is remote from the first nip zone, the slide plate being taken out of alignment with the first nip zone for the purpose of allowing access to the first nip zone.