A folding machine comprises a blade folding unit having a first and a second folding roller, the folding roller axes thereof defining a folding roller plane, and having a folding blade which is oriented and is movable in a folding blade plane which is oriented perpendicularly to the folding roller plane and intersects the folding roller plane in an intersection line. The folding blade is arranged in a retracted position in or below a horizontal plane which comprises the intersection line.

An embodiment of this disclosure provides a folding apparatus configured to stack and fold a designated number of sheets at a time. The folding apparatus includes a conveyor configured to sequentially convey the designated number of sheets, a stacker configured to temporarily store a sheet conveyed by the conveyor to stack the designated number of sheets, a sheet folding device configured to fold the designated number of sheets at a time, and control circuitry. The control circuitry is configured to cause the sheet folding device to fold the stored sheet in response to an occurrence of a sheet jam upstream from the stacker in a direction of sheet conveyance, in processing the designated number of sheets.

A collation folding device comprising one or more fold rollers mounted in fixed positions. Below and adjacent to the fold rollers are adjustable nip rollers to form nip spacing between the rollers. The adjustable nip roller is mounted on a nip axis shaft. An adjustment mechanism is used for moving the nip axis shaft to adjust the nip spacing. The nip adjustment mechanism includes a bearing block cam follower on which the nip axis shaft is fixedly mounted and supported. An eccentric cam in operative contact with the bearing block cam follower. Rotation of the eccentric cam on the eccentric cam axis drives the bearing block cam follower in its linear motion to adjust the nip spacing.

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.

A sheet folding apparatus includes a conveyance member to convey a sheet from an ejection member at a first speed lower than a conveyance speed by the ejection member or a second speed substantially same as or higher than the conveyance speed; a registration member; a pair of first and second rollers to rotate in forward and reverse directions; a plurality of folding rollers downstream from the second roller, to rotate in forward and reverse directions to fold the sheet; and circuitry to determine whether the sheet is equal to or smaller than a reference length from an exit position from the ejection member to a folding start position downstream from the pair of the first and second rollers. The circuitry performs first-speed folding when the sheet is equal to or smaller than the reference length and performs second-speed folding when the sheet is longer than the reference length.

An embodiment of this disclosure provides a folding apparatus configured to stack and fold a designated number of sheets at a time. The folding apparatus includes a conveyor configured to sequentially convey the designated number of sheets, a stacker configured to temporarily store a sheet conveyed by the conveyor to stack the designated number of sheets, a sheet folding device configured to fold the designated number of sheets at a time, and control circuitry. The control circuitry is configured to cause the sheet folding device to fold the stored sheet in response to an occurrence of a sheet jam upstream from the stacker in a direction of sheet conveyance, in processing the designated number of sheets.

A sheet folding apparatus includes a conveyance member to convey a sheet from an ejection member at a first speed lower than a conveyance speed by the ejection member or a second speed substantially same as or higher than the conveyance speed; a registration member; a pair of first and second rollers to rotate in forward and reverse directions; a plurality of folding rollers downstream from the second roller, to rotate in forward and reverse directions to fold the sheet; and circuitry to determine whether the sheet is equal to or smaller than a reference length from an exit position from the ejection member to a folding start position downstream from the pair of the first and second rollers. The circuitry performs first-speed folding when the sheet is equal to or smaller than the reference length and performs second-speed folding when the sheet is longer than the reference length.

A sheet processing apparatus includes conveyers to convey a sheet. The conveyers include a registration conveyer which a plurality of sheets is to sequentially contact and is configured to bend a preceding sheet contacting the registration conveyer toward a direction in which the preceding sheet does not obstruct an entry of a following sheet to the registration conveyer when the conveyers overlay and convey the plurality of sheets after the plurality of sheets sequentially contacts the registration conveyer.

The present invention provides a roller folder (100c). Existing roller folders do not provide sufficient entry margin for entry of intermediate items into the roller folder. The roller folder includes swiveling arms (212 or 224) that are angularly oriented from a first tangent (221) which increase entry margin (220) for the intermediate items such as paper strips. In some of embodiments, biasing members (237 or 238) restore positions of swivel arms (212 or 224) during folding operation. In other embodiments, slots (300 or 310) are provided for changing the angular orientation of the swiveling arms (212 or 224). The angular orientation of the swivel arms (212 or 224) reduces the occurrence of jamming of intermediate items while performing folding, pressing operations.

A sheet processing apparatus includes conveyers to convey a sheet. The conveyers include a registration conveyer which a plurality of sheets is to sequentially contact and is configured to bend a preceding sheet contacting the registration conveyer toward a direction in which the preceding sheet does not obstruct an entry of a following sheet to the registration conveyer when the conveyers overlay and convey the plurality of sheets after the plurality of sheets sequentially contacts the registration conveyer.