A sheet folding apparatus having two-folding rollers each of whose outer diameter gradually decreases from the central part to each end part, a folding plate which can move forward to or backward from a nip between the two-folding rollers, and has a cutout part located at an edge part of the folding plate facing the nip between central parts of the two-folding rollers, wherein the cutout part does not reach the nip between the central parts of the two-folding rollers when the sheets are folded, and a folding plate support member which is placed at a position facing the nip between the central parts of the two-folding rollers, and can slide in a direction of moving closer to or away from the nip, wherein the folding plate support member projects from the cutout part when the sheets are set, and does not reach the nip when the sheets are folded.

A sheet folding apparatus having two-folding rollers each of whose outer diameter gradually decreases from the central part to each end part, a folding plate which can move forward to or backward from a nip between the two-folding rollers, and has a cutout part located at an edge part of the folding plate facing the nip between central parts of the two-folding rollers, wherein the cutout part does not reach the nip between the central parts of the two-folding rollers when the sheets are folded, and a folding plate support member which is placed at a position facing the nip between the central parts of the two-folding rollers, and can slide in a direction of moving closer to or away from the nip, wherein the folding plate support member projects from the cutout part when the sheets are set, and does not reach the nip when the sheets are folded.

An apparatus for folding and receiving book documents comprises a main conveying device arranged and adapted to convey unfolded book documents in a main conveying direction and a secondary conveying device arranged and adapted to receive the book documents conveyed by the main conveying device and to convey them in a secondary conveying direction and/or against the secondary conveying direction, wherein the secondary conveying direction is transverse to the main conveying direction. Further, the apparatus comprises a receiving device arranged at a spatial distance from the first and/or the second conveying surface and configured to receive folded book documents. The device folds the conveyed book documents respectively with a movement in the secondary conveying direction and/or against the secondary conveying direction. Furthermore, a lifting device is arranged to convey the folded book documents from the main conveying device and/or from the secondary conveying device into the receiving device.

A sheet post-processing apparatus includes a stacker, a pair of folding rollers having a nip portion therebetween, and a blade. A sheet is stacked on the stacker. The blade is configured to fold the sheet in half by pushing the sheet stacked on the stacker into the nip portion of the pair of folding rollers. The pair of folding rollers are configured to switch between a first posture and a second posture. In the first posture, the sheet is pushed into the nip portion by the blade. In the second posture, a feeding direction of the sheet is different from that in the first posture.

In order to enable a sheet to be properly guided to a nip portion in performing folding processing, a sheet processing apparatus for performing folding processing on a sheet is provided with a rotating body pair which nips the sheet by a nip portion to rotate, and thereby draws the sheet to perform folding processing, a folding blade that pushes the sheet to the nip portion of the rotating body pair, and a blade guide member including a guide portion for pushing the sheet to the nip portion when the folding blade pushes the sheet to the nip portion, where the folding blade and blade guide member are relatively shifted so that a distance from a push front edge portion to the guide portion when the folding blade pushes the sheet to the nip portion is longer than a distance from the front edge portion to the guide portion.

To prevent displacement of first fold positions and collapse of discharged and stacked sheets when sheet fold processing is performed a plurality of times for each sheet. First fold processing is applied to a sheet conveyed to a conveying path by a rotating body pair 22. The sheet that has been subjected to the first fold processing is fed back to the conveying path while a first fold line is being opened. Then, second fold processing is applied to the sheet that has been fed back to the conveying path by the rotating body pair 22. The resultant sheet is discharged with the first fold line opened.

To prevent displacement of first fold positions and collapse of discharged and stacked sheets when sheet fold processing is performed a plurality of times for each sheet. First fold processing is applied to a sheet conveyed to a conveying path by a rotating body pair 22. The sheet that has been subjected to the first fold processing is fed back to the conveying path while a first fold line is being opened. Then, second fold processing is applied to the sheet that has been fed back to the conveying path by the rotating body pair 22. The resultant sheet is discharged with the first fold line opened.

A folding machine for folding fiber products and fiber products formed and stacked thereby are disclosed. The folding machine includes two folding devices, each of which includes a cutting device, a delivery wheel, a folding-line wheel, a platen wheel, and a folding wheel. The cutting device cuts the fiber product and transports the cut fiber product to the delivery wheel. The folding-line wheel is adjacent to the delivery wheel for making a first folding line on the fiber product carried by the delivery wheel, and then the platen wheel folds the fiber product along the first folding line. Subsequently, the once-folded fiber product is transported to the folding wheel. The folding wheels of the two folding devices are adjacent to each other and are used to fold the fiber product passing therethrough for a second time, and thus fiber products with three folds are formed.

A postprocessing device performs postprocessing on sheets received from an image forming apparatus. The postprocessing device includes a pair of folding rollers, a folding blade, a transport device, a drive portion, and a drive controller. The drive controller controls the drive portion to match moving speed of a tip portion of the folding blade with moving speed of a circumferential surface of the folding rollers, at a time point that the sheaf of the sheets makes contact with the circumferential surface of the folding rollers, when the image forming apparatus forms the image by ink jet printing, and to match the moving speed of the tip portion of the folding blade with the moving speed of the circumferential surface of the folding rollers, at a time point that the sheaf of the sheets reaches the nip region between the folding rollers.

In a sheet folding apparatus for folding a sheet, a sheet is pushed at a predetermined position thereof by a push member while the sheet is being conveyed by a conveyance roller. The predetermined position of the sheet is guided to the nip section of a folding roller pair. Then, the sheet is nipped at the predetermined position thereof and folded by the folding roller pair.