JP2015118357A5 - Imaging optical system, image forming apparatus and image reading apparatus including the same - Google Patents

Description

The present invention relates to an imaging optical system, and is suitable for a lens array optical system used in, for example, an image forming apparatus and an image reading apparatus.

Accordingly, an object of the present invention is to provide an imaging optical system capable of suppressing the shielding of the imaging light flux and the generation of ghost light.

To achieve the above object, an imaging optical system according to one aspect of the present invention includes a plurality of lenses arranged in a first direction, of the object in the first cross section parallel to the first direction A first lens array that forms an intermediate image; a second lens array that includes a plurality of lenses arranged in a first direction and re-images the intermediate image of the object in the first cross section; And a light shielding member disposed between optical axes of adjacent lenses in the second lens array, and at least one of the first and second lens arrays has a scattering portion between adjacent lens surfaces. Or it has a light absorption part, The width | variety in the 1st direction of a scattering part or a light absorption part is larger than the width | variety in the 1st direction of a light shielding member, It is characterized by the above-mentioned.
Further objects and other features of the present invention will become apparent from the preferred embodiments described below with reference to the accompanying drawings.

According to the present invention, in the imaging optical system, the imaging light beam is blocked and the ghost light is generated due to the relative positional fluctuation between the lens array and the light shielding member due to the placement error during manufacturing and the environmental temperature fluctuation, and the lens. Generation of ghost light due to the characteristic shape of the scattering portion provided between the surfaces can be suppressed.

A part 102a of the lens array optical system includes a first lens 107a, a part of the light shielding member 108, and a second lens 109a, which are arranged so as to be aligned with each other. The cross section perpendicular to the optical axis of the first lens 107a and the second lens 109a has a rectangular shape. The effective diameter of the surface on the light source 101 side (hereinafter referred to as G1R1 surface) of the first lens 107a and the surface on the photosensitive portion 103 side (hereinafter referred to as G2R2 surface) of the second lens 109a is 0.76 mm. is there. On the other hand, the effective diameter of the surface of the first lens 107a on the light shielding member 108 side (hereinafter referred to as G1R2 surface) and the surface of the second lens 109a on the light shielding member 108 side (hereinafter referred to as G2R1 surface). 0.69 mm. That is, the effective diameter is different for each surface of the lens.
A scattering part is provided between adjacent lens surfaces . Specifically, a scattering unit 110 is provided between the G1R2 surface of the first lens 107a and the G1R2 surface of the adjacent first lens (not shown). Similarly, the scattering portion 110 is also provided between the G2R1 surface of the second lens 109a and the G2R1 surfaces of the adjacent second lens (not shown). The light shielding member 108 of the present embodiment has a plurality of openings penetrating in the optical axis direction corresponding to the number of lenses constituting the lens array, and the light shielding wall between the adjacent openings is the optical axis of the adjacent lens. It is located in between and is arranged so as to match the scattering portion 110.
The light shielding member 108 is disposed between the optical axes of adjacent lenses in the main array section.
The light shielding member 108 may be configured to insert and fix a light shielding plate at fixed intervals in a frame extending in the main arrangement direction so as to demarcate the position in the main arrangement direction.
The first lenses 107a, 107b,... And the second lenses 109a, 109b,.

Here, ΔL is the distance from the position where the lens arrays 107 and 109 and the light shielding member 108 are positioned to the farthest position in the lens array optical system 102. In other words, ΔL is the distance from the portion where the lens array optical system 102 is positioned in the main array direction to the portion of the lens array optical system 102 farthest away. Further, the most distant position of the light shielding member 108 is the most distant position in the portion functioning as the light shielding member in the light shielding member 108.
ΔT is the difference between the temperature when the lens arrays 107 and 109 and the light shielding member 108 are positioned and the temperature when the lens array optical system 102 is used. In other words, ΔT is the difference between the temperature when the lens array optical system 102 is positioned and the temperature when the lens array optical system 102 is used.
ΔX is the absolute value of the difference between the linear expansion coefficient of the lens array 107 and the linear expansion coefficient of the member that defines (ie, positions) the light shielding members 108 in the main array direction and the sub array direction, and The larger of the absolute values of the difference between the linear expansion coefficient of the lens array 109 and the linear expansion coefficient of the member that defines (ie, positions) the light blocking members 108 in the main array direction and the sub array direction. Is the value of
ΔW is the difference between the width Bm of the scattering portion 110 along between lenses adjacent to the width Tm of the light shielding member 108 along between adjacent lenses in the main array direction in the main array direction (Bm-Tm).

Bm is the width of the scattering portion 110 in the main array direction , and Tm is the width of the light shielding member 108 in the main array direction . Further, Be is the distance between the ridge lines of the prisms at both ends in the scattering unit 110. That is, it means that the prism ridgeline formed in the scattering portion 110 is included only in the width Be.

Claims (13)

A first lens array for forming an intermediate image of the object in the first comprises a plurality of lenses arranged in a direction, the first in a first section parallel to the direction,
A second lens array including a plurality of lenses arranged in the first direction and re-imaging an intermediate image of the object in the first cross section;
A light shielding member disposed between optical axes of adjacent lenses in the first and second lens arrays,
Wherein at least one of the first and second lens array has a scattering portion or absorbance portion between the lens surfaces adjacent to,
The imaging optical system, wherein a width of the scattering portion or the light absorbing portion in the first direction is larger than a width of the light shielding member in the first direction. A first lens that includes a plurality of lenses arranged in a first direction and a second direction perpendicular to the first direction , and forms an intermediate image of the object in a first cross section parallel to the first direction. Lens array,
A second lens array including a plurality of lenses arranged in the first and second directions and re-imaging an intermediate image of the object in the first cross section;
A light shielding member disposed between optical axes of adjacent lenses in the first and second lens arrays,
Wherein at least one of the first and second lens array has a scattering portion or absorbance portion between the lens surfaces adjacent to,
The imaging optical system, wherein a width of the scattering portion or the light absorption portion in the second direction is larger than a width of the light shielding member in the second direction. Each of the first and second lens arrays includes a plurality of lenses arranged in the first direction and a second direction perpendicular to the first direction;
2. The imaging optical system according to claim 1, wherein a width of the scattering portion or the light absorption portion in the second direction is larger than a width of the light shielding member in the second direction. Temperature and the imaging when the distance from the portion where the imaging optical system in the first direction is positioned to the portion of the farthest image forming optical system [Delta] L, the imaging optical system is positioned ΔT is the difference from the temperature when the optical system is used, the absolute value of the difference between the linear expansion coefficient of the first lens array and the linear expansion coefficient of the member positioning the light shielding member, and the first absolute value of the difference between the linear expansion coefficient of the member linear expansion coefficient of the second lens array to be positioning the shielding member, the larger the ΔX of, the scattering portion or absorbance unit in the first direction when the difference in the width between the width of the light shielding member [Delta] W, and,
ΔL × ΔT × ΔX ≦ ΔW / 2
An imaging optical system according to any one of claims 1 to 3, characterized in that to satisfy the following condition. The light blocking member, wherein is arranged between the first lens array and the second lens array, wherein the scattering portion or width in the first direction of the absorption portion Bm, said light shielding member first The width in the direction 1 is Tm, the arrangement period of the first and second lens arrays is P, the length of the light shielding member in the direction of the optical axis is Ls, and the first lens array and the second lens when the maximum distance in the direction of the optical axis between the lens surface facing the array Lmax, a,
Bm + Tm ≧ P × (1− (Ls / Lmax))
An imaging optical system according to any one of claims 1 to 4, characterized in that to satisfy the following condition. The said length direction of the optical axis of the light shielding member may have smaller than the shortest distance in the direction of the optical axis between the opposing lens surfaces of the first lens array and the second lens array 6. The imaging optical system according to claim 1 , wherein the imaging optical system is characterized in that:   The absolute value of the difference between the linear expansion coefficient of the first lens array and the linear expansion coefficient of the member positioning the light shielding member, and the linear expansion coefficient of the second lens array and the light shielding member are positioned. ΔX is the larger of the absolute values of the difference from the linear expansion coefficient of the existing member, and ΔW is the difference between the width of the scattering part or light absorbing part and the width of the light shielding member in the first direction. ,
    105mm × 30 ° C × ΔX ≦ ΔW / 2
The imaging optical system according to claim 1, wherein the following condition is satisfied. The light shielding member, any of claims 1 to 7, characterized in that said that are located in at least one of the position of the image side of the first lens position and the second lens array of the object side of the array The imaging optical system according to claim 1.   9. The imaging optics according to claim 1, wherein at least one of the first and second lens arrays has a scattering portion between adjacent lens surfaces. 10. system. The scattering portion, the imaging optical system according to claim 9, characterized in that it comprises a plurality of prisms. When the distance between the ridges of the opposite ends of the prism before Symbol scattering portion and Be,
Tm ≧ Be
An imaging optical system according to claim 10, characterized in that to satisfy the following condition. An imaging optical system according to any one of claims 1 to 11, a developing device for developing an electrostatic latent image formed on the photosensitive surface by said imaging optical system as a toner image, which is the development an image forming apparatus comprising a transferring device for transferring the toner image to a transfer material, a fixing device for fixing the transferred toner image on the transfer material, that Ru comprising a. Image forming optical system according to any one of claims 1 to 11, and the light receiving portion you receive light from the focused original by said imaging optical system, characterized in that Ru provided with Reader.