An image forming apparatus includes: an inverting unit that inverts a sheet when an image forming process for forming images on both sides of the sheet is performed; an image forming unit that forms an image on a second side of the sheet based on first side image data and forms an image on a third side of the sheet based on second side image data; a controller that starts the image forming process upon receiving print data to be printed on specific paper, and inverts a sheet fed from a sheet feeding unit once or more; and a converting unit that, when the sheet fed from the sheet feeding unit is the specific paper, converts the first side print data which is received to be printed on the specific paper into N-th side image data where N2 and transfers the N-th side image data to the image forming unit.

Described herein is a security LEP ink composition comprising an absorber, a resin; and a carrier liquid for printing a security image.

An image forming apparatus according to an embodiment includes a decolorable image forming unit that forms a decolorable image with a decolorable material. A mask control unit controls the decolorable image forming unit to form, with the decolorable material on a sheet, a mask that hides at least one portion of an image formed on the sheet with non-decolorable material.

In general, according to one embodiment, an image forming apparatus includes a display unit, an operation input unit, a storage unit, a control unit, and an image forming unit. The operation input unit receives an operation input. The storage unit stores function restriction instruction content that disables setting and use of a predetermined function related to printing, so as to correspond to a sheet handling method after image formation. The control unit displays a setting screen for setting each function related to printing and selecting the sheet handling method on the display unit, acquires the function restriction instruction content corresponding to the selected sheet handling method from the storage unit when the sheet handling method is selected, displays the setting screen in which setting and use of the predetermined function are disabled on the display unit on the basis of the acquired function restriction instruction content, and receives print setting on the setting screen. The image forming unit is controlled by the control unit on the basis of the setting received on the setting screen and forms an image on a sheet.

An image forming apparatus includes an image forming device that forms an image on a recording medium and circuitry that controls the image forming device. The image forming device forms an invisible image with an invisible material on the recording medium and forms a visible image with a visible material on the invisible image. Each of first and second adhesion amounts includes respective adhesion amounts of the visible material and the invisible material per unit area in a portion, in which the visible image is formed on the invisible image, of the composite image. The second adhesion amount is smaller than the first adhesion amount. The controller adjusts the amount of the invisible material included in the second adhesion amount to be smaller than that included in the first adhesion amount, to cause the image forming device to form the image according to the second adhesion amount.