A sheet processing device sandwiches a sheet-shaped medium in a two-ply sheet in which two sheets are overlaid and partially bonded. The sheet processing device includes a separator, a conveyor, and a switching member. The separator separates the two sheets of the two-ply sheet. The conveyor is disposed downstream from the separator in a sheet conveyance direction and conveys the two-ply sheet. The switching member is disposed downstream from the conveyor in the sheet conveyance direction. The switching member switches a conveyance path of the two-ply sheet to convey the two-ply sheet to a fixing path on which fixing processing is performed on the two-ply sheet or a non-fixing path on which no fixing processing is performed on the two-ply sheet.

A sheet processing apparatus is configured to sandwich one or more sheet media in a two-ply sheet in which two sheets are overlaid and bonded together at a portion of the two-ply sheet. The sheet processing apparatus includes circuitry configured to control insertion processing to insert the one or more sheet media into the two-ply sheet based on a length of the two-ply sheet in a conveyance direction, a length of one of the one or more sheet media in the conveyance direction, and a number of the one or more sheet media.

A sheet processing device inserts a sheet-shaped medium into a two-ply sheet in which two sheets are overlaid and partially bonded. The sheet processing device includes control circuitry to execute a single insertion mode in which one sheet-shaped medium is inserted into the two-ply sheet and a multiple insertion mode in which a plurality of sheet-shaped media are inserted into the two-ply sheet along a conveyance direction. The control circuitry inserts the one sheet-shaped medium into the two-ply sheet in the single insertion mode and the plurality of sheet-shaped media into the two-ply sheet in the multiple insertion mode, with the two-ply sheet being stopped.

An image forming apparatus includes a sheet separation device, a first sheet feeder, a second sheet feeder, an image forming device, and circuitry. The sheet separation device is configured to separate a non-bonding portion of a two-ply sheet in which two sheets are overlapped and bonded together at a bonding portion of the two-ply sheet. The first sheet feeder is configured to feed the two-ply sheet. The second sheet feeder is configured to feed an inner sheet to be inserted between the two sheets. The image forming device is configured to form an image on a surface of the inner sheet. The circuitry is configured to cause the first sheet feeder to feed the two-ply sheet, perform a sheet separating operation on the two-ply sheet and cause the second sheet feeder to start feeding the inner sheet before completion of the sheet separating operation on the two-ply sheet.

A sheet processing device is configured to separate a non-bonding portion of a two-ply sheet in which two sheets are overlapped and bonded together at one end as a bonding portion of the two-ply sheet. The sheet processing device includes a first sheet feeder configured to feed the two-ply sheet, a second sheet feeder configured to feed an inner sheet to be inserted between the two sheets of the two-ply sheet in a state in which the non-bonding portion of the two-ply sheet is separated, and circuitry configured to cause the first sheet feeder to feed the two-ply sheet, perform a sheet separating operation on the two-ply sheet to separate the non-bonding portion of the two-ply sheet, and cause the second sheet feeder to start feeding the inner sheet before completion of the sheet separating operation on the two-ply sheet.

A sheet processing device sandwiches a sheet-shaped medium in a two-ply sheet in which two sheets are overlaid and partially bonded. The sheet processing device includes a separator, a conveyor, and a switching member. The separator separates the two sheets of the two-ply sheet. The conveyor is disposed downstream from the separator in a sheet conveyance direction and conveys the two-ply sheet. The switching member is disposed downstream from the conveyor in the sheet conveyance direction. The switching member switches a conveyance path of the two-ply sheet to convey the two-ply sheet to a fixing path on which fixing processing is performed on the two-ply sheet or a non-fixing path on which no fixing processing is performed on the two-ply sheet.

A sheet separation device separates a non-bonding portion of a two-ply sheet in which two sheets are overlapped and bonded together at a bonding portion of the two-ply sheet. The sheet separation device includes a winding roller and a gripper. The winding roller rotates and winds the two-ply sheet to separate the two-ply sheet. The gripper is disposed in the winding roller and configured to grip a gripped portion of the two-ply sheet at one end of the two-ply sheet without abutting a tip of the gripped portion at the one end of the two-ply sheet on a member.

A sheet processing device includes a conveyor, a rotator, a separator, and control circuitry. The conveyor conveys a two-ply sheet in which two sheets are overlapped and bonded together at a portion of the two-ply sheet. The rotator winds the two-ply sheet. The control circuitry causes the conveyor to convey the two-ply sheet in a winding direction to wind the two-ply sheet around the rotator such that a sagging space is created in the two-ply sheet, and causes the separator to insert into the sagging space to separate the two-ply sheet into two sheets. The control circuitry causes the conveyor to convey the two-ply sheet in a direction opposite the winding direction before an insertion of the separator into the sagging space.

A sheet processing device is configured to separate a non-bonding portion of a two-ply sheet in which two sheets are overlapped and bonded together at one end as a bonding portion of the two-ply sheet. The sheet processing device includes a first sheet feeder configured to feed the two-ply sheet, a second sheet feeder configured to feed an inner sheet to be inserted between the two sheets of the two-ply sheet in a state in which the non-bonding portion of the two-ply sheet is separated, and circuitry configured to cause the first sheet feeder to feed the two-ply sheet, perform a sheet separating operation on the two-ply sheet to separate the non-bonding portion of the two-ply sheet, and cause the second sheet feeder to start feeding the inner sheet before completion of the sheet separating operation on the two-ply sheet.

A sheet processing device is configured to separate a non-bonding portion of a two-ply sheet in which two sheets are overlapped and bonded together at one end as a bonding portion of the two-ply sheet. The sheet processing device includes a first sheet feeder configured to feed the two-ply sheet, a second sheet feeder configured to feed an inner sheet to be inserted between the two sheets of the two-ply sheet in a state in which the non-bonding portion of the two-ply sheet is separated, and circuitry configured to cause the first sheet feeder to feed the two-ply sheet, perform a sheet separating operation on the two-ply sheet to separate the non-bonding portion of the two-ply sheet, and cause the second sheet feeder to start feeding the inner sheet before completion of the sheet separating operation on the two-ply sheet.