The invention relates to a device for conveying and guiding mail items in a postage meter provided with an inkjet print head, in which postage meter each mail item, which has a top face and a bottom face, passes under the print head between a top reference surface defined by the bottom surface of a stationary guide plate and a bottom reference surface, said device having at least two drive assemblies mounted transversely side-by-side and to move vertically independently from each other, so that the top surfaces of the mail items remain continuously pressed against said stationary guide plate regardless of the thickness of the mail item, and in particular when said thickness varies over the width of the mail item.