An image forming apparatus includes a controller circuitry configured to control the ink-jet module to form a density adjustive image pattern on one of the multiple sheets, detect a jam during continuous feeding, and then determine whether or not images, which are to be formed on one or more fed-and-unejected sheets, include the density adjustive image pattern, where the images include the density adjustive image pattern, determine whether or not the unejected sheet, on which the density adjustive image pattern is to be formed, has passed through a certain position of the sheet conveyer path, and control the ink-jet module, where the unejected sheet, on which the density adjustive image pattern is to be formed, has passed through the certain position, not to re-form the density adjustive image pattern and to re-form images on rest of the unejected sheets.