An image forming apparatus including an image forming unit, a fixing unit, a temperature sensor, and a controller to execute a printing operation is provided. The printing operation is conducted at one of a first high-temperature printing pace, a first low-temperature printing pace, a second high-temperature printing pace, and a second low-temperature printing pace depending on a temperature detected by the temperature sensor. The first low-temperature printing pace is one of lower and equal to the first high-temperature printing pace. The second low-temperature printing pace is one of lower and equal to the second high-temperature printing pace. An absolute difference between the second high-temperature printing pace and the second low-temperature printing pace is greater than an absolute difference between the first high-temperature printing pace and the first low-temperature printing pace.

The digital printing process includes the printing of liquid toner on both substrate sides. Thereto developed portions of a first and a second liquid toner are transferred to the first side and fused by exposure to infrared radiation and by subsequent contact fusing. The substrate is conditioned for a further transfer step by maintaining a substantially uniform water content therein during and after the fusing step, in which further transfer step at least one further developed portion of liquid toner is transferred to a side of the substrate. This occurs particularly by limiting heat development in the liquid toner, such as by using a black toner liquid with an absorbance at 800 nm of at most than 0.8.

Folding information and printing surface information, included in content information of a sealed letter creation job, are compared with content printing conditions stored in a storage section, and an appropriate condition (a conveyance path after printing, execution/non-execution of image rotation, and printing page order) is selected such that the position of a window of a windowed envelope is aligned with the position of specifying information printed on a print sheet P to be a content when the print sheet P is enclosed in the envelope. A convey section and a printing section are controlled based on the selected content printing condition.

An image forming apparatus includes an image bearing member, a transfer device, a voltage applying portion, a fixing device, and a controller. During execution of an operation in an output mode, the controller is capable of selectively executing: an operation in which test images formed on a first side of a first recording material are fixed and then the first recording material is outputted without forming the test images on a second side of the first recording material and then in which a second recording material is passed through the fixing device without forming the test images on a first side of the second recording material and then the test images are transferred onto a second side of the second recording material.

An image forming apparatus includes an image forming unit configured to form an image including an adhesive image by powder adhesive on a sheet that is conveyed; a bonding unit, to which sheets on which the image has been formed by the image forming unit are conveyed in order, configured to, by heating a plurality of sheets conveyed to and stacked in the bonding unit, bond the plurality of sheets, using adhesive images formed on the plurality of sheets; and a control unit configured to evaluate a temperature of the plurality of sheets conveyed to the bonding unit and, based on the evaluated temperature, control an amount of heat to be applied to the plurality of sheets by the bonding unit heating the plurality of sheets.