Abstract: A method for manufacturing optical scanning systems by which plural optical scanning systems with different effective scanning widths can be manufactured by changing a polygon mirror alone is provided. The method includes the steps of designing a first scanning optical system using a first polygon mirror corresponding to a first value of effective scanning width; designing a second scanning optical system provided with a second polygon mirror corresponding to a second value of effective scanning width, the second value being smaller than the first value, wherein a reference point of deflection is located at the position of the reference point of deflection of the first scanning optical system; and adjusting a size and a position of the scanning lens so as to adjust a lateral magnification in a cross section in the sub-scanning direction of the imaging optical system.

Abstract: A method of producing a mold for a microlens array with a cutting tool rotating around a rotation axis, microlenses having the substantially same shapes. A z-axis of an (x, y, z) coordinate system is in the direction of the central axis of a surface of the mold. The method includes the steps of cutting a surface of the mold while each of angle ? between the rotation axis of the cutting tool and a straight line passing through a point on the rotation axis and parallel to the z-axis and angle ? of a plane containing the rotation axis and the straight line around the straight line is kept constant; and cutting the plural surfaces while the values of angle ? and angle ? are determined such that a variance of the values of at least one of angle ? and angle ? is greater than a predetermined value.

Abstract: A method for manufacturing optical scanning systems by which plural optical scanning systems with different effective scanning widths can be manufactured by changing a polygon mirror alone is provided. The method includes the steps of designing a first scanning optical system using a first polygon mirror corresponding to a first value of effective scanning width; designing a second scanning optical system provided with a second polygon mirror corresponding to a second value of effective scanning width, the second value being smaller than the first value, wherein a reference point of deflection is located at the position of the reference point of deflection of the first scanning optical system; and adjusting a size and a position of the scanning lens so as to adjust a lateral magnification in a cross section in the sub-scanning direction of the imaging optical system.

Abstract: The reflector is provided with plural reflector units. Each reflector unit is shaped as a prism or a cylinder provided with a retroreflective structure at one end, the retroreflective structure is configured to reflect incident rays from the other end of the prism or the cylinder in a direction of incidence, and in a reference cross section of the reflector unit, the reference cross section containing the central axis of the prism or the cylinder and the reference cross section being determined such that the shape of the retroreflective structure is line-symmetric with respect to the central axis in the reference cross section, the shape of a light receiving surface at the other end is line-symmetric with respect to the central axis and has a portion inclined with respect to a direction perpendicular to the central axis in the reflector unit.

Abstract: A microlens array includes N microlenses arranged in a predetermined direction on an x-y plane. A projection onto the x-y plane of the vertex of each microlens is arranged in the vicinity of a lattice point of a reference lattice on the x-y plane, the lattice spacing of the reference lattice in the predetermined direction being D/M (millimeters) where M is a positive integer. A distance between two sides of a lens facing each other is approximately equal to D, and a distance between the projection onto the x-y plane of the vertex of the lens and the projection onto the x-y plane of a side of the lens is D/2+?i. Letting n represent the refractive index of the material of each microlens and letting f (millimeters) represent the focal length of each microlens, the following relationships are satisfied. 0.0042 D < D 2 ? ? f = D ? ( n - 1 ) 2 ? ? R 0.0048 ? f ? { 1 + ( D / 2 ? ? f ) 2 } < ? < 0.

Abstract: A microlens array includes N microlenses arranged in a predetermined direction on an x-y plane. A projection onto the x-y plane of the vertex of each microlens is arranged in the vicinity of a lattice point of a reference lattice on the x-y plane, the lattice spacing of the reference lattice in the predetermined direction being D/M (millimeters) where M is a positive integer. A distance between two sides of a lens facing each other is approximately equal to D, and a distance between the projection onto the x-y plane of the vertex of the lens and the projection onto the x-y plane of a side of the lens is D/2+?i. Letting n represent the refractive index of the material of each microlens and letting f (millimeters) represent the focal length of each microlens, the following relationships are satisfied. 0.0042 D < D 2 ? ? f = D ? ( n - 1 ) 2 ? ? R 0.0048 ? f ? { 1 + ( D / 2 ? ? f ) 2 } < ? < 0.

Abstract: In an optical scanning system, each of plural light beams is reflected at a point on a deflector in a sub-scanning cross section, a point of reflection on the deflector of the principal ray of each beam in the case that the principal ray is incident normally to a scanning surface in a main scanning cross section is designated as a fiducial point, distance from the fiducial point to the scanning surface is designated as L, distance from the center of curvature of the exit surface of one of the second scanning lenses for a light beam i to the scanning surface is designated as BFi, refractive powers of the first scanning lens and one of the second scanning lenses are designated as ?1si and ?2si, and then the following expressions are satisfied. 0.15?BFi/L?0.2??(1) 0.

Abstract: An optical scanning system includes a variable-focus element, an imaging lens and a deflector, wherein the reciprocal of the focal length f of the variable-focus element is changed from 1/fMIN to 1/fMAX, and for the case that the equation 1/f={(1/fMAX)+(1/fMIN)}/2 holds, a beam which has passed through the variable-focus element is a divergent beam, and x 2 + x 2 2 x 1 > x 3 ( 1 ) is satisfied, where x1 represents a distance from a virtual image point of the divergent beam to the principal point on the entry side of the variable-focus element, x2 represents a distance from the principal point on the exit side of the variable-focus element to the principal point on the entry side of the imaging lens, and x3 represents a distance from the principal point on the exit side of the imaging lens to an image point.

Abstract: An optical scanning system includes a variable-focus element, an imaging lens and a deflector, wherein the reciprocal of the focal length f of the variable-focus element is changed from 1/fMIN to 1/fMAX, and for the case that the equation 1/f={(1/fMAX)+(1/fMIN)}/2 holds, a beam which has passed through the variable-focus element is a divergent beam, and x 2 + x 2 2 x 1 > x 3 ( 1 ) is satisfied, where x1 represents a distance from a virtual image point of the divergent beam to the principal point on the entry side of the variable-focus element, x2 represents a distance from the principal point on the exit side of the variable-focus element to the principal point on the entry side of the imaging lens, and x3 represents a distance from the principal point on the exit side of the imaging lens to an image point.

Abstract: The method includes the steps of: obtaining lateral magnification of an optical scanning system; obtaining the maximum value of thickness in the optical axis direction of an scanner lens; obtaining allowance b on one side and beam diameter a in the vertical scanning direction in the lens; and obtaining width h in the vertical scanning direction of the lens by the following expression h=a+2b. The allowance b is a product of the maximum value of thickness in the optical axis direction of the lens and a coefficient, and the coefficient is determined according to the lateral magnification of the system in such a way that the maximum value of movement of the focal point of the lens due to moisture absorption is made smaller than or equal to a predetermined value.

Abstract: The method includes the steps of: obtaining lateral magnification of an optical scanning system; obtaining the maximum value of thickness in the optical axis direction of an scanner lens; obtaining allowance b on one side and beam diameter a in the vertical scanning direction in the lens; and obtaining width h in the vertical scanning direction of the lens by the following expression h=a+2b. The allowance b is a product of the maximum value of thickness in the optical axis direction of the lens and a coefficient, and the coefficient is determined according to the lateral magnification of the system in such a way that the maximum value of movement of the focal point of the lens due to moisture absorption is made smaller than or equal to a predetermined value.