A paper feeding apparatus includes a tray, an air blower, a floating detector, and a hardware processor. In the tray, a sheet of paper is loaded. The air blower blows air to the sheet loaded in the tray to float the sheet. The floating detector is provided above the sheet loaded in the tray and detects the floating of the sheet to a predetermined level. The hardware processor causes the air blower to blow the air and determines a basis weight of the sheet loaded in the tray from an air amount that has caused the floating detector to detect the floating of the sheet.

A sheet suction device includes a sheet carrier, a suction unit, and a rotary body. The sheet carrier has a carrying region. The carrying region includes a plurality of suction openings. The sheet carrier is configured to rotate while holding a sheet. The suction unit is configured to communicate with the plurality of suction openings and suck air via the plurality of suction openings. The rotary body is disposed between the plurality of suction openings and the suction unit. The rotary body is configured to rotate to change a number of suction openings that communicate with the suction unit, among the plurality of suction openings of the sheet carrier.

A sheet suction device includes a sheet carrier, a suction unit, and a rotary body. The sheet carrier has a carrying region. The carrying region includes a plurality of suction openings. The sheet carrier is configured to rotate while holding a sheet. The suction unit is configured to communicate with the plurality of suction openings and suck air via the plurality of suction openings. The rotary body is disposed between the plurality of suction openings and the suction unit. The rotary body is configured to rotate to change a number of suction openings that communicate with the suction unit, among the plurality of suction openings of the sheet carrier.

A medium feeding device includes a container member that accommodates sheet media, a discharging member located further than the media accommodated in the container member in a discharging direction in which the media are discharged, to discharge the media one by one, a hand-over member disposed above the container member to suck the media accommodated in the container member with air and pass the media to the discharging member, a floating device disposed on a side of the media accommodated in the container member to blow air to an upper area of a side end surface of the media to float the media while an upper portion of the media is separated, a detector that detects a separation state of the medium floated by the floating device, and a controller that controls a medium-feeding operation including a pre-feeding blowing operation and a during-feeding blowing operation, the pre-feeding blowing operation serving as an air blowing operation performed by the floating device before the medium is fed, and the during-feeding blowing operation serving as an air blowing operation performed by the floating device from a start of feeding the medium and an end of feeding the medium. While performing the pre-feeding blowing operation or the during-feeding blowing operation, the controller performs detection with the detector, and on condition that a result of the detection fails to satisfy a preset target range, the controller changes a parameter for the medium-feeding operation including at least one of the pre-feeding blowing operation or the during-feeding blowing operation.

A conveying apparatus includes a conveyor and a conveyed object receptor. The conveyor includes a conveyance surface facing downward and configured to convey a conveyed object having a sheet-like shape. The conveyed object receptor is arranged below the conveyor and configured to receive the conveyed object having fallen from the conveyor.

A conveying apparatus includes a conveyor and a conveyed object receptor. The conveyor includes a conveyance surface facing downward and configured to convey a conveyed object having a sheet-like shape. The conveyed object receptor is arranged below the conveyor and configured to receive the conveyed object having fallen from the conveyor.

Perforated endless conveying belts are stretched between drive and idle rollers. A suction box is arranged between upper and lower belt portions of the perforated endless conveying belts. Abutment members are attached to positions of a support corresponding to the perforated endless conveying belts and pressed against the perforated endless conveying belts. The upstream of the suction box from the abutment members forms an attracting area, and intake holes are formed therein. Lifting plates extend to at least an intake hole range of the attracting area between the perforated endless conveying belts. The lifting plates move between a first position to vertically open the intake holes and project from conveying surfaces of the perforated endless conveying belts and a second position to close the intake holes and retract from the conveying surfaces of the perforated endless conveying belts.

Perforated endless conveying belts are stretched between drive and idle rollers. A suction box is arranged between upper and lower belt portions of the perforated endless conveying belts. Abutment members are attached to positions of a support corresponding to the perforated endless conveying belts and pressed against the perforated endless conveying belts. The upstream of the suction box from the abutment members forms an attracting area, and intake holes are formed therein. Lifting plates extend to at least an intake hole range of the attracting area between the perforated endless conveying belts. The lifting plates move between a first position to vertically open the intake holes and project from conveying surfaces of the perforated endless conveying belts and a second position to close the intake holes and retract from the conveying surfaces of the perforated endless conveying belts.

Method for controlling a sheet feeding device (1) comprising an elevator (2) for a stack of sheets, and an air supply system (3) configured to supply and direct one of more air streams towards an upper region (4) of the sheet feeding device for floating a plurality of upper sheets of the stack of sheets, wherein the elevator comprises a vertically movable support (5) for supporting the stack of sheets from below, wherein the sheet feeding device comprises an optical sensor (6) positioned adjacent the floated sheets for measuring light reflected from the floated sheets at a plurality of different heights, wherein the method comprises the steps of: continuously deriving from the optical sensor a density reading (DR) indicating the density of sheets floated, continuously deriving an average density (AD) based on a plurality of density readings, continuously deriving an upper density limit (UDL) based on the average density multiplied by a predetermined upper density limit factor (UDLF), continuously deriving a lower density limit (LDL) based on the average density multiplied by a predetermined lower density limit factor (LDLF), adjusting a first operating parameter (OP) of the sheet feeding device should the density reading exceed the upper density limit, wherein the adjustment of the first operating parameter is such as to decrease the density of floated sheets, and adjusting the first operating parameter of the sheet feeding device should the density reading subceed the lower density limit, wherein the adjustment of the first operating parameter is such as to increase the density of floated sheets. Also, a sheet feeding device connected to a controller configured to operate according to this method.

Method for controlling a sheet feeding device (1) comprising an elevator (2) for a stack of sheets, and an air supply system (3) configured to supply and direct one of more air streams towards an upper region (4) of the sheet feeding device for floating a plurality of upper sheets of the stack of sheets, wherein the elevator comprises a vertically movable support (5) for supporting the stack of sheets from below, wherein the sheet feeding device comprises an optical sensor (6) positioned adjacent the floated sheets for measuring light reflected from the floated sheets at a plurality of different heights, wherein the method comprises the steps of: continuously deriving from the optical sensor a density reading (DR) indicating the density of sheets floated, continuously deriving an average density (AD) based on a plurality of density readings, continuously deriving an upper density limit (UDL) based on the average density multiplied by a predetermined upper density limit factor (UDLF), continuously deriving a lower density limit (LDL) based on the average density multiplied by a predetermined lower density limit factor (LDLF), adjusting a first operating parameter (OP) of the sheet feeding device should the density reading exceed the upper density limit, wherein the adjustment of the first operating parameter is such as to decrease the density of floated sheets, and adjusting the first operating parameter of the sheet feeding device should the density reading subceed the lower density limit, wherein the adjustment of the first operating parameter is such as to increase the density of floated sheets. Also, a sheet feeding device connected to a controller configured to operate according to this method.