IMAGE FORMING APPARATUS USING A PLURALITY OF TONER PATCHES DURING A NON-PRINTING PERIOD

An image forming apparatus includes a controller configured to control a toner-image forming device to form a toner patch; and a detector configured to detect the toner patch on the image carrier. During a non-printing period, the controller causes a toner-image forming device to form toner patches, causes the detector to detect densities of the toner patches, and adjusts an image-forming condition of the toner-image forming device based on detected densities. During a printing period, the controller causes the toner-image forming device to form an output image in an image area and form fewer toner patches in a non-image area, causes the detector to detect densities of the fewer toner patches, and adjusts the image-forming condition of the toner-image forming device based on detected densities. The fewer toner patches are selected from and fewer than the plurality of toner patches formed during the non-printing period.