Patent ID: 8836992

Claim:
An image forming apparatus comprising: a conveying unit that conveys a recording medium; a movable body that includes a recording head to eject a liquid droplet for image recording to the recording medium, and is supported movably in a main-scanning direction orthogonal to a conveying direction of the recording medium; a movable-body drive unit that moves the movable body in the main-scanning direction; an adjustment-pattern recording controller configured to cause a plurality of adjustment patterns to be recorded with a predetermined edge interval in the main-scanning direction by causing the liquid droplet ejected from the recording head to land on the recording medium, while causing the movable-body drive unit to move the movable body in the main-scanning direction; a reading unit that is mounted on the movable body to irradiate the recording medium on which the adjustment patterns are recorded with read light and read the adjustment patterns by photoelectrically converting reflected light from the recording medium; a calculator configured to calculate a positional deviation correction amount for correcting a deviation of a landing position of the liquid droplet, which is ejected from the recording head and landed on the recording medium, based on an ideal interval between the adjustment patterns recorded on the recording medium and a read result of the adjustment patterns read by the reading unit; a correction unit configured to cause the adjustment-pattern recording controller to record the adjustment pattern at a recording position where the interval between the adjustment patterns becomes an integral multiple of a fluctuation cycle in a relative movement of the reading unit and the adjustment pattern, which is caused by movement of the movable body mounted with the reading unit, and correct the recording position of the adjustment pattern based on the positional deviation correction amount calculated by the calculator; and an ejection timing adjustment unit configured to adjust an ejection timing of the liquid droplet by the recording head by performing repeatedly at least twice a recording process of the adjustment pattern on the recording medium by the adjustment-pattern recording controller, a reading process of the adjustment patterns by the reading unit, a calculation process of the positional deviation correction amount by the calculator, and a correction process of the recording position of the adjustment pattern by the correction unit.