Image forming apparatus and light-emitting-device head

A light-emitting-device head comprising:

• a first light-emitting-device arrangement including light emitting devices arranged in lines extending in a first scanning direction;
• a second light-emitting-device arrangement including light emitting devices arranged in lines extending in the first scanning direction, the second light-emitting-device arrangement overlapping the first light-emitting-device arrangement in a second scanning direction at least in part;
• an optical device that forms an electrostatic latent image by focusing light emitted from the light emitting devices on a photoconductor and exposing the photoconductor to the light;
• and
• a switching unit that switches the light-emitting-device arrangement to be lit up between the first light-emitting-device arrangement and the second light-emitting-device arrangement at a switching position defined at any position in an overlapping portion where the first light-emitting-device arrangement and the second light-emitting-device arrangement overlap each other;
• and
• a correcting unit that corrects, at the switching position, density variation occurring in an image formed on a recording medium.

An image forming apparatus comprising:

• means for forming a toner image by using a first light-emitting-device arrangement and a second light-emitting-device arrangement in each of which light-emitting devices are arranged in lines extending in a first scanning direction, the second light-emitting-device arrangement overlapping the first light-emitting-device arrangement in a second scanning direction at least in part, and an optical device that forms an electrostatic latent image by focusing light emitted from the light-emitting devices on a photoconductor and exposing the photoconductor to the light;
• means for transferring the toner image to a recording medium;
• means for fixing the toner image transferred to the recording medium and finishes the image;
• means for switching the light-emitting-device arrangement to be lit up between the first light-emitting-device arrangement and the second light-emitting-device arrangement at a switching position defined at any position in an overlapping portion where the first light-emitting-device arrangement and the second light-emitting-device arrangement overlap each other;
• means for acquiring information on density variation at the switching position in the image formed on the recording medium;
• and
• means for correcting the density variation with reference to the information on density variation.