| 摘要 |
PURPOSE:To eliminate the need for a focus adjustmemt by forming a positioning member which sets the reference surface of a short-focus, small-diameter image forming element array structure in the optical axis-direction at a specific position and a guide member which moves original glass in one body. CONSTITUTION:When the distance from the reference surface of the short-focus, small-diameter image forming array structure 2 to the center of the structure 2 is denoted as (d), a surface AA in the center of the optical distance from an original surface 1' to the image formation surface of a photosensitive drum 3 is coincident to the center of said element array 2, and the distance l0 between the reference surface of the array structure 2 and the exposure surface of the photosensitive drum 3 is expressed by an equation I . A holding member 14 which has a positioning surface 14b at distance l0 from the image formation surface of the photosensitive drum 3 is fixed to a front-side plate 13, and an platen glass receiving surface 14a is constituted in one body over the holding member 14 in sliding contact with the platen glass 1. |
