Patent ID: 7142229

Claim:
An exposure apparatus, comprising: a light emitting device array in which a plurality of light emitting devices capable of being controlled and driven independently are arranged in a primary scanning direction to form a device row and a plurality of the device rows are arranged in a secondary scanning direction intersecting with the primary scanning direction, such that the light emitting devices are aligned in the secondary scanning direction with respect to a photosensitive material in the secondary scanning direction; and a drive-control device for driving and controlling each of the light emitting devices so as to cause the plurality of device rows arranged in the secondary scanning direction to be sequentially illuminated on a time-division basis; wherein when the plurality of device rows are illuminated in a direction identical to the secondary scanning direction, the device rows are arranged with a pitch that is expressed by an equation (1) given below, and when the plurality of device rows are illuminated in a direction opposite to the secondary scanning direction, the device rows are arranged with a pitch T that is expressed by an equation (2) given below, T =( m− 1/ n ) P (1) T =( m+ 1/ n ) P (2) where P is a pitch of an exposure pixel, m is an integer equal to or greater than 2, and n is a number of the device rows arranged in the secondary scanning direction.