A sheet stacking system is disclosed that has improved tolerance for sheets that are not flat. Successive sheets are aligned onto a stack by a plurality of registration belts. The heights of the pivoting registration belts are compared with one another to determine the unevenness of the top of the stack. This unevenness is represented by the difference between the heights of the highest and lowest registration belt .sub.stack-height and is monitored to quantify the planarity of the top of the stack. When the unevenness (.sub.stack-height) exceeds a threshold, the system switches to a modified method to control the elevation of the stack. This method may include stopping the machine from stacking before the unevenness is too large for the registration belts to uniformly drive sheets. This invention prevents the stacker from attempting to stack when sheets are expected to skew thereby preventing jams and unusable stacks.

A printing apparatus includes: a sheet discharge tray having an upstream portion tilted to extend downward in a direction of gravity; an upper member limiting a height of a space above the sheet discharge tray; a full sensor configured to detect an upstream end of a top sheet of sheets stacked on the sheet discharge tray; a counter configured to count a number of the sheets discharged onto the sheet discharge tray; and a controller. The controller determines whether to stop discharging of the sheets to the sheet discharge tray, based on a detection result of the full sensor upon the sheets to be stacked on the sheet discharge tray including only sheets each with uniform thickness and based on a count value of the counter upon the sheets to be stacked on the sheet discharge tray including a sheet with thickness varying partly.

A printing apparatus includes: a sheet discharge tray having an upstream portion tilted to extend downward in a direction of gravity; an upper member limiting a height of a space above the sheet discharge tray; a full sensor configured to detect an upstream end of a top sheet of sheets stacked on the sheet discharge tray; a counter configured to count a number of the sheets discharged onto the sheet discharge tray; and a controller. The controller determines whether to stop discharging of the sheets to the sheet discharge tray, based on a detection result of the full sensor upon the sheets to be stacked on the sheet discharge tray including only sheets each with uniform thickness and based on a count value of the counter upon the sheets to be stacked on the sheet discharge tray including a sheet with thickness varying partly.

A device for detecting a foreign object attached on a surface of a sheet-like medium, comprising a static electricity providing part (A) for providing static electrical charges, a medium transporting part (B) for transporting a medium under detection, and a static electricity sensor and identifier part (C). The medium transporting part comprises a static electricity receiving unit and a static electricity absorbing unit sequentially connected. The static electricity receiving unit is connected to the static electricity providing part (A), and the static electricity absorbing unit is connected to the static electricity sensor and identifier part (C). The static electricity receiving unit is configured to transfer the static electrical charges obtained from the static electricity providing part (A) to the medium under detection. The static electricity absorbing unit is configured to absorb the static electrical charges of the medium under detection.

A sheet binding processing apparatus including a crimp binding member that performs binding processing on a predetermined region of a sheet by sandwiching and pressing the sheet between an upper tooth and a lower tooth meshing with each other, and a detection unit that detects a state of the predetermined region of the sheet to be bound by the crimp binding member. If the detection unit detects that the predetermined region is not capable of binding, the binding processing on the predetermined region is prohibited.

A sheet binding processing apparatus including a crimp binding member that performs binding processing on a predetermined region of a sheet by sandwiching and pressing the sheet between an upper tooth and a lower tooth meshing with each other, and a detection unit that detects a state of the predetermined region of the sheet to be bound by the crimp binding member. If the detection unit detects that the predetermined region is not capable of binding, the binding processing on the predetermined region is prohibited.

A diverter conveyor includes a frame supporting an upper conveyor that has an upstream end and a downstream end and that is configured to carry sheets in a first, downstream, direction. A plurality of nip rollers are mounted on the frame upstream of the upstream end of the upper conveyor and are spaced from the upstream end of the upper conveyor by a gap. The nip rollers feed the sheets along a main path to the upstream end of the upper conveyor. A rejection conveyor is supported by the frame and has a portion beneath the gap and extends away from the upper conveyor at an acute angle. A plurality of paddles are mounted at the first gap, and an actuator is operably connected to the paddles and configured to shift the paddles from a first position out of the main path to a second position in the main path.

A diverter conveyor includes a frame supporting an upper conveyor that has an upstream end and a downstream end and that is configured to carry sheets in a first, downstream, direction. A plurality of nip rollers are mounted on the frame upstream of the upstream end of the upper conveyor and are spaced from the upstream end of the upper conveyor by a gap. The nip rollers feed the sheets along a main path to the upstream end of the upper conveyor. A rejection conveyor is supported by the frame and has a portion beneath the gap and extends away from the upper conveyor at an acute angle. A plurality of paddles are mounted at the first gap, and an actuator is operably connected to the paddles and configured to shift the paddles from a first position out of the main path to a second position in the main path.

A paper sheet handling machine (for example, a banknote handling machine (10)) includes: a storage unit (for example, an escrow unit (20), banknote storages (30), a banknote storage cassette (40)) configured to store a paper sheet transported from a transport unit (16); and a shifting unit (19) provided in the transport unit (16) and configured to shift the paper sheet transported by the transport unit (16), in a width direction orthogonal to a direction in which the paper sheet is transported, according to a position, in the width direction, of a specific member (for example, a tape (136) in the escrow unit (20), a pair of feed rollers of a banknote feeding mechanism (32, 42) provided in the banknote storages (30), a banknote storage cassette (40)) in the storage unit.

A method for transferring a sheet in a sheet transport assembly from a supplying conveyor to a receiving conveyor. The method includes arranging a contact side of a sheet in contact with a transport belt of the supplying conveyor, advancing the sheet on the transport belt in a transport direction along a process unit, which applies a process to a process side of the sheet opposite to the contact side, and to a transfer area where the sheet is transferred to a receiving conveyor. To correct for curl deformation of the sheet, air flow is directed onto the process side of sheet, which urges the sheet towards a supporting element. The air flow is controlled in response to a curl deformation behavior of the sheet.