Image forming apparatus

An image forming apparatus, comprising:

• a recording head configured to eject ink corresponding to an image to be printed, using arranged nozzles;
• a control unit configured to determine nozzles corresponding to the image to be printed and cause the recording head to eject ink from the nozzles;
• and
• an ejection malfunction nozzle detecting unit configured to (a) cause the recording head to print a test pattern on a print sheet using the recording head, and (b) detect an ejection malfunction nozzle on the basis of a scanned image of the test pattern;
• wherein the test pattern includes plural test pattern images of a line shape or a band shape such that in each of the plural test pattern images a dot is not formed at a dot position of a target nozzle by setting the target nozzle as a non ejection nozzle;
• the target nozzles of the plural test pattern images are sequentially shifted by one nozzle in a primary scanning direction;
• the ejection malfunction nozzle detecting unit determines an ejection malfunction nozzle on which ejection deviation occurs, on the basis of density decreasing amounts of respective density decrease parts in the plural test pattern images in the scanned image;
• and
• the ejection malfunction nozzle detecting unit determines as an ejection malfunction nozzle on which ejection deviation occurs a nozzle between a position of the target nozzle in a test pattern image of which the density decreasing amount is largest and a position of the target nozzle in a test pattern image of which the density decreasing amount is smallest.