A control system controls an image forming unit that includes a charging device, an image bearer to be charged by the charging device, a light-emitting device array including a plurality of light emitting devices, and a driving causing the light emitting devices to emit light to form a latent image on the image bearer. The control system includes a storage unit, a corrector, and a controller. The storage unit is configured to store a light-amount correction value of each of the light emitting devices. The corrector is configured to correct a pixel value of each pixel in image data, based on the light-amount correction value of each light emitting device stored in the storage unit. The controller is configured to control the driver to cause each light emitting device to emit light based on image data for which a pixel value of each pixel has been corrected.

An optical line sensor reads an inspection object conveyed in a sub-scanning direction by a reading line L extending in a main scanning direction and includes a plurality of light-receiving lenses 11 and a plurality of light-receiving elements. The plurality of light-receiving lenses 11 are arranged along the main scanning direction. The plurality of light-receiving elements are arranged linearly along the main scanning direction, and receive light transmitted through the plurality of light-receiving lenses 11. The plurality of light-receiving lenses 11 are arranged to be separated from each other by a diameter of the light-receiving lens 11 or longer. A plurality of light-receiving elements 121 form at least one row or more of the reading lines L.