Patent ID: 7857407

Claim:
An image forming apparatus comprising: a liquid ejection head including a plurality of nozzles, the liquid ejection head ejecting a first liquid containing a coloring material through the nozzles onto a recording medium while the liquid ejection head and the recording medium are relatively moved in a first direction; an abnormal nozzle identifying device which identifies, out of the nozzles, an abnormal nozzle for which an error in a landing position of the first liquid on the recording medium with respect to a second direction orthogonal to the first direction is not less than a predetermined amount; and a correcting device which corrects dot data in such a manner that a second dot on the recording medium formed from the first liquid subsequently ejected from the abnormal nozzle makes contact with at least part of a first dot on the recording medium formed from the first liquid previously ejected from the abnormal nozzle wherein when one of the nozzles ejects droplets of the first liquid continuously at a frequency higher than a predetermined frequency so that the ejected droplets are deposited on the recording medium to make contact with one another, the deposited droplets spread out more in the second direction than in other directions and form spread dots on the recording medium, and wherein in a case where there are the abnormal nozzles adjacent to one another in a projected nozzle row obtained by projecting the nozzles so that the nozzles are aligned in the second direction, the correcting device corrects the dot data in such a manner that a third dot formed by one of the abnormal nozzles and a fourth dot formed by the other of the abnormal nozzles are not aligned in the second direction.