Sheet laminator, image forming apparatus, and sheet laminating method

A sheet laminator configured to laminate a two-ply sheet in which two sheets are overlapped and bonded together at one end of the two-ply sheet and a sheet-shaped medium inserted between the two sheets of the two-ply sheet, the sheet laminator comprising:

• a sheet feeder configured to feed the two-ply sheet;
• a multi-feeding detector disposed downstream from the sheet feeder in a conveyance direction in which the two-ply sheet is conveyed, the multi-feeding detector being configured to detect multiple feeding of the two-ply sheet;
• a fixing device disposed downstream from the multi-feeding detector in the conveyance direction, the fixing device being configured to fix the two-ply sheet by application of heat and pressure;
• an ejection device disposed downstream from the fixing device in the conveyance direction, the ejection device being configured to eject the two-ply sheet that has been fixed by the fixing device;
• a purging portion disposed at a position different from the ejection device, the purging portion including a retracted sheet conveyance passage branched at a point upstream from the fixing device in the conveyance direction;
• a passage switcher disposed upstream from the fixing device and the purging portion in the conveyance direction, the passage switcher being configured to switch a conveyance passage of the two-ply sheet to the fixing device or to the purging portion;
• and
• circuitry configured to, in response to detection of multiple feeding of the two-ply sheet, convey the two-ply sheet to the purging portion and retry sheet feeding with another two-ply sheet.