Abstract: A star wheel releasing mechanism for a printing apparatus is described. The star wheel releasing mechanism comprises a base, the exit wheels disposed at the base, a star wheel module, a pair of supporting plates and a front cover. The base includes a first side and a second side. The star wheel module having a plurality of star wheels is movably disposed on the base. The supporting plates are oppositely disposed at the first side and the second side of the base. Each supporting plate has an arc slot. Two ends of the star wheel module are respectively slidable within the arc slots of two supporting plates. The front cover pivoted on the supporting plates and connected to the star wheel module is movable between a first position and a second position.

Abstract: To prevent wavy swell from causing in sheet in transferring thereof and avoid wrinkle from being produced in later printing steps, there is provided a sheet transfer machine forward from a printing drum and a press roll. The machine is provided with upper and lower guide plates respectively formed with hole portions. Upper and lower rolls are disposed at the hole portions. There are provided hold rollers for pressing sheet coming from between the upper and the lower guide plates to an upper face of the lower guide plate downstream from the upper roll in a direction of transferring print sheet. In printing, swell is prevented from being produced by pressing the print sheet coming from between the two rolls by the hold rollers. When the sheet is sandwiched by the printing drum and the press roll and printed in later steps, wrinkle is not produced in the print sheet.