Patent ID: 8414098

Claim:
An image forming device comprising: a print head formed with a plurality of print elements for forming an image on a recording medium, the print elements including a downstream element and an upstream element positioned upstream of the downstream element in a conveying direction; a head moving mechanism for reciprocatingly moving the print head in a first direction and a second direction opposite to the first direction, wherein both the first direction and the second direction are orthogonal to the conveying direction, and the print head performs a bi-directional printing including a first print for forming a first image while being moved in the first direction and a second print for forming a second image while being moved in the second direction; a conveying mechanism that conveys the recording medium toward a downstream side in the conveying direction relative to the print head; a first memory that stores one of a positional offset amount and a positional offset calibration value, the positional offset amount indicating an offset between a first printing position when performing the first print and a second printing position when performing the second print, the positional offset calibration value being determined based on the positional offset amount; a determining unit that determines one of the first printing position and the second printing position that is located upstream in the conveying direction by referring to the one of the positional offset amount and the positional offset calibration value, in the case where performing an overlap print that overlaps images by the first print and the second print, wherein in the case where performing the overlap print, the conveying mechanism conveys the recording medium to a first position that is determined based on a predetermined distance prior to the first print and to a second position that is determined based on the predetermined distance and the one of the positional offset amount and the positional offset calibration value prior to the second print, wherein in the case where performing the overlap print, the first print is performed prior to the second print when the determining unit determines that the first printing position is located upstream of the second printing position, whereas the second print is performed prior to the first print when the determining unit determines that the second printing position is located upstream of the first printing position.