Optical scanning system

An optical scanning system that comprises first and second light sources, a polygon mirror and first to fourth scanning lenses and is configured such that a first light beam emitted by the first light source is reflected by the polygon mirror and passes through the first scanning lens and the third scanning lens and a second light beam emitted by the second light source is reflected by the polygon mirror and passes through the second scanning lens and the fourth scanning lens,

• wherein when A1 represents the vertex of the object-side surface of the first scanning lens, A2 represents the vertex of the object-side surface of the second scanning lens, an x-axis is defined to be in a direction of the central axis of the polygon mirror, a y-axis is defined to be in a scanning direction of the light beams, a z-axis is defined to be orthogonal to the x-axis and the y-axis, P1 represents a reference point of deflection of the first light beam, P2 represents a reference point of deflection of the second light beam, L1 represents a distance in the z-axis direction between the point P1 and the point A1, L2 represents a distance in the z-axis direction between P2 and A2, Lp12 represents a distance in the z-axis direction between P1 and P2, h1 represents a thickness in the x-axis direction of the first scanning lens, h2 represents a thickness in the x-axis direction of the second scanning lens, θ1 represents an acute angle that a projection of the principal ray of the first light beam onto a plane containing the x-axis and the y-axis forms with the y-axis and θ2 represents an acute angle that a projection of the principal ray of the second light beam onto a plane containing the x-axis and the y-axis forms with the y-axis,
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• are satisfied and
• wherein the optical scanning system is configured such that a light beam emitted by each light source is substantially focused at each reference point of deflection in the direction corresponding to the x-axis direction of the light beam on each surface to be scanned and a lateral magnification in the x-axis direction from each reference point of deflection to each surface to be scanned is in a range from 2 to 3.