A cover feeder for providing book covers to a production unit of a book completion line includes a first receiving device for book covers of the same format, which can be positioned individually, in an overlapping flow and/or in a stack thereon, and a second receiving device that is arranged upstream of the first receiving device for a stack of book covers having different formats. The cover feeder includes a control unit to which information can be transmitted relating to the format and sequence of book covers in the stack of book covers having different formats, and a laterally adjustable centering device connected to the control unit for a defined lateral displacement and/or aligning of respectively one book cover that is separated out from the second receiving device and is positioned on the first receiving device.

A method for providing a stack of book covers for production of finished books includes supplying a task stack of book covers having identical cover formats and stacked one above another in an unknown or known sequence. Each book cover in the task stack includes an identifier comprising cover information. The book covers are separated out and conveyed from the task stack as separate book covers in a sequence that does not change until a completion signal is transmitted. The separated out book covers are counted, an identifier on each separated out book cover is detected, and cover information is read out of the respective identifier stored. The separated out book covers are deposited on top of one another in the sequence in which they were separated out for forming a detected stack. An identifier is stored that identifies the detected stack together with the temporarily stored cover information.

A sheet feeding apparatus includes a sheet stacking portion, a lift plate, an actuating segment, driving unit, a sheet feeding portion, a first detecting portion, a remaining amount detection portion. The remaining amount detection portion includes a detection piece, a link mechanism, a second detecting portion, a controller. The link mechanism couples together the driving shaft and the detection piece at a coupling position attained by pivoting the lift plate through a predetermined angle from a lower limit position in rotation direction, so as to let the driving shaft and the detection piece rotate together. The second detecting portion senses whether or not the detection piece is present. The controller determines the remaining quantity level of the stacked sheets according to whether or not the second detecting portion is detecting the detection piece being present.

An image forming system includes an image forming apparatus, a first conveyance path, a sheet feeding unit, a sheet post-processing unit, and a controller. The image forming apparatus has a first feed portion, and an image forming portion. The sheet feeding apparatus has a sheet stacking portion, a second feed portion, a relay conveyance portion, and a remaining amount detecting portion. When, during continuous printing, the existing number of recording sheets present in a conveyance passage from a confluence portion to the first feed portion is more than the constituting number of recording sheets contained in one bundle of sheets and in addition the sensing result of the remaining amount sensor is equal to or less than a predetermined amount, the controller controls first feed portion such that the existing number of the recording sheets is less than the constituting number of recording sheets.

A sheet feeding apparatus includes a sheet stacking portion, a lift plate, an actuating segment, driving unit, a sheet feeding portion, a first detecting portion, a remaining amount detection portion. The remaining amount detection portion includes a detection piece, a link mechanism, a second detecting portion, a controller. The link mechanism couples together the driving shaft and the detection piece at a coupling position attained by pivoting the lift plate through a predetermined angle from a lower limit position in rotation direction, so as to let the driving shaft and the detection piece rotate together. The second detecting portion senses whether or not the detection piece is present. The controller determines the remaining quantity level of the stacked sheets according to whether or not the second detecting portion is detecting the detection piece being present.

An image forming system includes an image forming apparatus, a first conveyance path, a sheet feeding unit, a sheet post-processing unit, and a controller. The image forming apparatus has a first feed portion, and an image forming portion. The sheet feeding apparatus has a sheet stacking portion, a second feed portion, a relay conveyance portion, and a remaining amount detecting portion. When, during continuous printing, the existing number of recording sheets present in a conveyance passage from a confluence portion to the first feed portion is more than the constituting number of recording sheets contained in one bundle of sheets and in addition the sensing result of the remaining amount sensor is equal to or less than a predetermined amount, the controller controls first feed portion such that the existing number of the recording sheets is less than the constituting number of recording sheets.

A cover feeder for providing book covers to a production unit of a book completion line includes a first receiving device for book covers of the same format, which can be positioned individually, in an overlapping flow and/or in a stack thereon, and a second receiving device that is arranged upstream of the first receiving device for a stack of book covers having different formats. The cover feeder includes a control unit to which information can be transmitted relating to the format and sequence of book covers in the stack of book covers having different formats, and a laterally adjustable centering device connected to the control unit for a defined lateral displacement and/or aligning of respectively one book cover that is separated out from the second receiving device and is positioned on the first receiving device.

A book case processing portion of a book production line forms a combination with a device for the removal of at least one book case from a stream of book cases conveyed in a main conveying direction along the book case processing portion of the book production line. The device includes a deposit tray that is extendible into the stream to remove the at least one book case from the stream of book cases.