A display apparatus that switches and displays a plurality of operation screens each including an operation object selectable by an operator and having a layered structure includes a storage unit which stores information on guidance of prompting an operator to select a predetermined operation object, a recognizing unit which recognizes that an operation object is added or deleted, and an update unit which updates information on guidance in response to a relation between an operation screen to/from which the operation object is added or deleted and an operation screen positioned higher or lower than the operation screen such that content of the guidance provided on the basis of the information reflects configurations of the plurality of operation screens after addition or deletion of the operation object, when the operation object is added or deleted.

An image forming apparatus includes an image forming device which forms an image on a recording medium and an image scanning device which transmits scanned image data to the image forming device. The image forming device includes a receiver, a first image forming unit, a second image forming unit, and a controller. The receiver receives at least one of external image data transmitted from an external device and the scanned image data as input image data. The first image forming unit forms a developer image based on the input image data on the recording medium. The second image forming unit forms a mark image on the recording medium. The controller determines whether to make the second image forming unit form the mark image or not depending on a type of a transmission source of the input image data.

In an embodiment, a processor-readable medium stores code representing instructions that when executed by a processor cause the processor to access a list of print jobs for printing. The processor further determines a healthy area of a transfer media. For each job in the list, the processor calculates an image risk area (IRA) based on the healthy area, and ranks each job in a print order according to its IRA.

An image forming apparatus includes a transfer portion, a fixing unit, a conveyance belt configured to convey a sheet from the transfer portion toward the fixing unit, a driving portion configured to drive the conveyance belt, and a controller configured to control the driving portion. The controller is configured to, in a case of switching the image forming apparatus to a standby state in which the image forming apparatus is ready to start an image forming operation and stands by for input of an image forming job, execute preheating in which the fixing unit is preliminarily heated, and cause the driving portion to rotate the conveyance belt while the preheating is executed.