An imaging device includes a photoreceptor portion including a plurality of photoreceptors arranged in an array, a microlens array including a plurality of microlenses, and a light shielding layer placed between the photoreceptor portion and the microlens array. The pigment composition is prepared by mixing a press cake of the pigment with a liquid containing a selected type of dispersant before the resulting slurry is dried. At least a part of a surface of the rotary disk includes a conductor, and the conductor is electrically connected to a detecting terminal disposed inside the storing bowl.