US Patent 7339603 Exposure device for an electrophotographic apparatus

An exposure device for an electrophotographic apparatus including one or more laser light sources which expose an image carrier in accordance with a print information signal supplied from an external information processing apparatus, a resolution switching lens, and a switching unit to switch over a low resolution and a high resolution by inserting and extracting the resolution switching lens into and from a laser optical path. Preferably, a light emission time of each of the laser light sources with respect to the print information signal is changeable.