An image sheet forming method includes supplying a first sheet including a non-transparent layer, and transferring a toner image onto a toner image carrying surface of the first sheet. The method further includes integrating a second sheet, which includes a base layer and a transparent layer, with the first sheet in a manner that the toner image is sandwiched between the toner image carrying surface of the first sheet and the transparent layer of the second sheet. The method further includes separating the base layer from the second sheet while fixing the toner image.