A sheet stacker includes a load table to stack a bundle of sheets; a conveyor to convey a sheet to the load table in a conveyance direction at a conveyance speed; a guide including a holder to: hold a leading end of the sheet conveyed by the conveyor by the holder at a standby position; and move the holder to guide the sheet along a movement path in the conveyance direction at a moving speed while holding the sheet by the holder; and a leading-end alignment mechanism including a partition extending to the movement path of the holder, the leading-end alignment mechanism to align, in the conveyance direction, a leading-end position of the sheet on the load table; and circuitry configured to differentiate the conveyance speed of the conveyor and the moving speed of the holder.

A device for storing a sheet pile in a converting machine (10) comprises a transfer mechanism (28) for delivering sheets (22) into a piling area (26) of the device (22), and a sampling plate (44) which is adjustable between a sampling position and an access position, wherein the top of the piling area (26) is covered by the sampling plate (44) when the sampling plate (44) is in the sampling position and the top of the piling area (26) is free when the sampling plate (44) is in the access position.

A sheet material processing unit (20, 22, 24) comprises a transport system (32) for transporting sheets (12) or parts thereof from a respective input end (20i, 22i, 24i) to a respective output end (20o, 22o, 24o). A gripper unit (46) is releasably coupled to the transport system (32) and is configured for holding at least a part of one of the sheets (12). Additionally, at least one handover mechanism (47d, 47r) is provided being configured for decoupling the gripper unit (46) from the transport system (32) and providing the gripper unit (46) to a neighboring sheet material processing unit (20, 22, 24) and/or receiving a gripper unit (46) from a neighboring sheet material processing unit (20, 22, 24) and coupling the received gripper unit (46) to the corresponding transport system (32). Additionally, a sheet material processing machine (10) is presented which comprises at least two such sheet material processing units (20, 22, 24).

A sheet stacker includes: a loader to which a sheet bundle is to be loaded; a guide to receive a leading end of a sheet conveyed to an area above the loader, and guide the sheet along a guide path above the loader in a conveyance direction; a blower disposed above the guide path of the guide to blow air downward to the sheet; and multiple lines: disposed above the guide path of the guide; and extending in a direction inclined relative to the conveyance direction.