Patent ID: 7845786

Claim:
An image forming apparatus, comprising: an ink ejection device which ejects ink through nozzles, the ink containing coloring material; a treatment liquid ejection device which ejects treatment liquid through nozzles, the treatment liquid being a colorless transparent liquid containing no coloring material, the treatment liquid containing infrared-absorbing material and having at least one of an action of insolubilizing the coloring material in the ink when contacting with the ink, an action of aggregating the coloring material in the ink when contacting with the ink, and an action of preventing dispersion of the coloring material in the ink when contacting with the ink; a test pattern formation control device which controls the treatment liquid ejection device to eject the treatment liquid to form a prescribed test pattern onto one of a recording medium and an intermediate transfer body by depositing the treatment liquid, the prescribed test pattern being formed with only the treatment liquid on which the ink is not superimposed; an infrared irradiating device which irradiates infrared light onto the treatment liquid having been ejected from the treatment liquid ejection device; a treatment liquid determination device which includes a photoelectric transducer having sensitivity to the infrared light and determining a formation state of the prescribed test pattern formed with only the treatment liquid on which the ink is not superimposed; and a treatment liquid ejection defect judgment device which judges a number and positions of defective ones of the nozzles of the treatment liquid ejection device according to a determination signal obtained from the photoelectric transducer of the treatment liquid determination device; and an image processing device which specifies a deposition arrangement of the ink in such a manner that usage rate for the nozzle of the ink ejection device corresponding to the position of the defective nozzle of the treatment liquid ejection device is reduced.