Patent ID: 7597438

Claim:
An image forming apparatus, comprising: an ejection head which ejects ink having electrorheological properties onto a recording medium; an electric field application device which applies an electric field to a droplet of the ink deposited on the recording medium; a fixing promotion device which performs fixing promotion process for promoting fixing of the ink on the recording medium; a timing control device which controls a time difference between an electric field application cessation timing at which an application of the electric field to the ink on the recording medium by the electric field application device is ceased and a fixing promotion process timing at which the fixing promotion process is performed by the fixing promotion device; a conveyance device which causes the ejection head and the recording medium to move relatively to each other by conveying at least one of the ejection head and the recording medium in a relative movement direction; wherein: the electric field application device has a structure which is divided into a plurality of electrode regions aligned in the relative movement direction, electrode pairs each including a first electrode and a second electrode being disposed respectively in the electrode regions; the timing control device changes the region in which the electric field is generated by controlling application and non-application of voltage to the electrode pairs of the respective electrode regions; the electric field application device has an electrode region corresponding to a printing region of an ejection head and a plurality of electrode regions disposed in a range from a trailing end of the printing region until a process region of the fixing promotion device; and an electric field generation area is changed in terms of a conveyance direction of the recording medium by selectively applying voltage to the plurality of electrode regions according to at least one of a type of the recording medium, a type of the ink, and an ejection volume of the ink.