To form a high definition image by an image forming apparatus while prolonging the lifetime of a light emitting element provided in an exposure head.
A recess 40 is formed in the light exit plane Sb of a substrate S and a lens array 27 is provided at a position opposing the pixel electrode 30 of each organic EL element 24 on the bottom 40a of the recess 40 using an optical adhesive 43. Lens arrays 27 corresponding in number to that of the organic EL elements 24 are provided at positions opposing the pixel electrodes 30 of each organic EL element 24. Furthermore, each lens array 27 is constituted of a light guide fiber 42 extending toward a photosensitive drum and a microlens 26 provided at the photosensitive drum side end of the light guide fiber 42. Length L of each light guide fiber 42 is adjusted appropriately such that light exiting each microlens 26 forms a focus on the photosensitive drum.
Fujitsuna Hideyoshi
Osamu Suzawa