In a mail processing machine having a receive deck for receiving a stack of mail items for printing, jogging means for jogging the stack of items against a reference wall, selection means for extracting mail items for printing one by one from stack of items, and print means for printing a postal imprint on the selected mail item, a jogging device is provided that includes an external strip slidably mounted on a moving slideway and having a jogging flat mounted at the terminal end thereof, a brake-forming friction shoe secured to the stationary slideway and mounted between the stationary slideway and the moving slideway, and a resilient element having one end connected to the moving slideway and its other end connected to the external strip in order to cause the external strip to back off automatically through a determined distance from the moving slideway once the jogging flap has been brought into contact with the stack of mail items.