Patent ID: 8382226

Claim:
An image forming system configured to eject ink onto a sheet conveyed in a first direction comprising: a first head including a plurality of first ejection ports configured to eject the ink; a second head including a plurality of second ejection ports configured to eject the ink and an end part overlapping with the first head; an input part to which ejection port information on the plurality of first ejection ports and the plurality of second ejection ports is input; and a controller configured to control ejection of the ink from the first ejection ports and the second ejection ports based on the ejection port information, wherein the first head includes an end part overlapping with the second head, the plurality of first ejection ports and the plurality of second ejection ports are aligned in a second direction intersecting with the first direction, the second head in a shifted position in the first direction with respect to the first head is shifted in the second direction with respect to the first head so as to form an overlapped area in which a first printing area defined by the plurality of first ejection ports and a second printing area defined by the plurality of second ejection ports overlap with each other in the second direction, the plurality of first ejection ports include a first reference ejection port defining an edge of the overlapped area, the plurality of second ejection ports include a second reference ejection port defining an edge of the overlapped area, the second reference election port being closest to the end part of the second head among the plurality of second ejection ports, the first reference election port is positioned closest to the second reference ejection port among the plurality of first election ports, the ejection port information includes information for defining a first ejection port between the first reference ejection port and the end part of the first head as inactive ejection port that does not eject the ink, and the controller selectively switches between ejection of the ink from the first reference ejection port and ejection of the ink from the second reference ejection port and causes the ink to be ejected from the plurality of first ejection ports excluding the first ejection port defined as the inactive ejection port.