According to one embodiment, a sheet post-processing device includes a first tray to receive sheets from an image forming unit, a second tray to receive sheets from the first tray, and a third tray to receive sheets from the second tray. The third tray is movable relative to the second tray. A bundle claw is configured to move sheets in a first direction from the second tray to the third tray. A controller is configured to move the third tray relative to the second tray according to the sheets on the second tray. Depending on various characteristics of the sheets on the second tray or the presence of sheets already on the third tray, the position of the third tray may be changed to reduce possible misalignments of sheets in the transfer from the second to third tray.

According to one embodiment, a sheet post-processing device includes a first tray to receive sheets from an image forming unit, a second tray to receive sheets from the first tray, and a third tray to receive sheets from the second tray. The third tray is movable relative to the second tray. A bundle claw is configured to move sheets in a first direction from the second tray to the third tray. A controller is configured to move the third tray relative to the second tray according to the sheets on the second tray. Depending on various characteristics of the sheets on the second tray or the presence of sheets already on the third tray, the position of the third tray may be changed to reduce possible misalignments of sheets in the transfer from the second to third tray.

A sheet processing apparatus for processing sheets includes: a stack tray on which a sheet is stacked; a discharge roller pair composed of first and second rollers and configured to discharge a sheet onto the stack tray, the second roller being configured to be movable between a pressure contact position to contact with the first roller and a retracting position to separate from the first roller; and a pressure contact/separation mechanism for moving the second roller from the retracting position to the pressure contact position. The pressure contact/separation mechanism changes the timing at which the second roller reaches the pressure contact position according to the type of a sheet to be discharged.

A sheet processing apparatus for processing sheets includes: a stack tray on which a sheet is stacked; a discharge roller pair composed of first and second rollers and configured to discharge a sheet onto the stack tray, the second roller being configured to be movable between a pressure contact position to contact with the first roller and a retracting position to separate from the first roller; and a pressure contact/separation mechanism for moving the second roller from the retracting position to the pressure contact position. The pressure contact/separation mechanism changes the timing at which the second roller reaches the pressure contact position according to the type of a sheet to be discharged.

A sheet conveyer, having a sheet tray, a tray-driving mechanism, a conveyance guide, a feed roller, a conveyer-driving mechanism, a first sensor, and a controller, is provided. The controller controls the tray-driving mechanism and the conveyer-driving mechanism, during a sequential conveying action, when the first sensor detects an upper-surface level being at a lower limit of a correct range, delay a lift-start timing, at which the tray-driving mechanism starts moving the sheet tray upward, to be later at least than a timing, at which the feed roller after feeding one of the sheets completely and pausing resumes rotating for feeding a next one of the sheets, and cause the sheet tray to complete moving to a higher position prior to completion of feeding of the next sheet.

A sheet conveyer, having a sheet tray, a tray-driving mechanism, a conveyance guide, a feed roller, a conveyer-driving mechanism, a first sensor, and a controller, is provided. The controller controls the tray-driving mechanism and the conveyer-driving mechanism, during a sequential conveying action, when the first sensor detects an upper-surface level being at a lower limit of a correct range, delay a lift-start timing, at which the tray-driving mechanism starts moving the sheet tray upward, to be later at least than a timing, at which the feed roller after feeding one of the sheets completely and pausing resumes rotating for feeding a next one of the sheets, and cause the sheet tray to complete moving to a higher position prior to completion of feeding of the next sheet.

A sheet conveying device includes a sheet placement table, a sheet discharge table, a conveyance mechanism, raising/lowering mechanism, and a raising/lowering control portion. The sheet discharge table is located below the sheet placement table. The conveyance mechanism conveys a sheet placed on the sheet placement table onto the sheet discharge table via an execution position at which image processing is executed by an image processing portion. The raising/lowering mechanism raises and lowers the sheet placement table. The raising/lowering control portion controls the raising/lowering mechanism in accordance with a clearance that is defined by a height from the sheet on the sheet discharge table to the sheet placement table, so as to maintain the clearance to be equal to or higher than a set value.

A sheet conveying device includes a sheet placement table, a sheet discharge table, a conveyance mechanism, raising/lowering mechanism, and a raising/lowering control portion. The sheet discharge table is located below the sheet placement table. The conveyance mechanism conveys a sheet placed on the sheet placement table onto the sheet discharge table via an execution position at which image processing is executed by an image processing portion. The raising/lowering mechanism raises and lowers the sheet placement table. The raising/lowering control portion controls the raising/lowering mechanism in accordance with a clearance that is defined by a height from the sheet on the sheet discharge table to the sheet placement table, so as to maintain the clearance to be equal to or higher than a set value.

A rotation device rotates a sheet on an upstream side of, in a sheet conveyance orientation, a working device positioned in a middle of a conveyance path, thereby changing an orientation of the sheet. An information acquiring portion acquires sheet size information and sheet orientation information representing a size and the orientation of the sheet in a sheet storing portion, and working position information representing a working position on the sheet. A rotation control portion controls the rotation device in accordance with the sheet orientation information and the working position information. The working control portion controls the working device in accordance with the orientation of the sheet after passing through the rotation device, and the sheet size information and the working position information.

A rotation device rotates a sheet on an upstream side of, in a sheet conveyance orientation, a working device positioned in a middle of a conveyance path, thereby changing an orientation of the sheet. An information acquiring portion acquires sheet size information and sheet orientation information representing a size and the orientation of the sheet in a sheet storing portion, and working position information representing a working position on the sheet. A rotation control portion controls the rotation device in accordance with the sheet orientation information and the working position information. The working control portion controls the working device in accordance with the orientation of the sheet after passing through the rotation device, and the sheet size information and the working position information.