An optical apparatus for developing an image by using an electrostatic latent image and forming an image by transferring the developed image to a printing medium, the apparatus comprising:
- a linear light exposure device;
- a photoconductive medium on which an electrostatic latent image is formed by light irradiated from the linear light exposure device;
- a developing unit for developing the electrostatic latent image formed on the photoconductive medium;
- a transferring unit for transferring the image developed by the developing unit to a printing medium;
- and
- a fixing unit for fixing the image transferred to the printing medium,
- wherein the linear light exposure device includes:
- a light source module in which light emitting elements are arranged in at least one line;
- and a lens array for irradiating light emitted from the light source module to a surface to be exposed, the lens array including:
- an image side lens array unit in which a plurality of lens cells are arranged in at least one line in an arrangement direction and arranged having optical axes thereof parallel with each other;
- a columnar light blocking unit provided on an incidence surface of the image side lens array unit;
- and a light source side lens array unit spaced apart from the image side lens array unit by the light blocking unit, the light blocking unit having light transmission regions, through which light is transmitted toward each lens cell of the image side lens array unit, and light blocking regions in regions other than the light transmission regions,
- wherein the light blocking regions include partition walls, by which the light transmission regions are partitioned,
- wherein the light source side lens array unit includes a plurality of lens cells arranged in at least one line in the arrangement direction,
- wherein one of the plurality of lens cells of the image side lens array unit, one of the plurality of lens cells of the light source side lens array unit, and one of the light transmission regions share a common one of the optical axes, and each has a square effective optical region,
- wherein cross sections perpendicular to the common optical axis of the one of the lens cells of the image side lens array unit, one of the lens cells of the light source side lens array unit and the one of the light transmission regions are square, and
- wherein the light transmission regions face directly light emitting surfaces of the lens cells of the light source side lens array unit and light incident surfaces of the lens cells of the image side lens array unit, respectively.