Optical device, image reading apparatus and adjusting method for optical device

1. An optical device equipped with a mirror which reflects light, comprising:

a plurality of first receiving parts that touch one face in one end in a lengthwise direction of said mirror; and

a plurality of first pressing parts that touch a face opposing to said face to which said first receiving parts touch, and press said mirror with elastic force toward said first receiving parts, wherein

two among said first receiving parts and two among said first pressing parts are set up separately each other respectively, and said two first pressing parts are installed such that they are located between said two first receiving parts sandwiching said mirror.

2. An optical device according to claim 1 , further comprising:

one second receiving part that touches one face in an other end of said mirror; and

one second pressing part that touches a face opposing to said face to which said second receiving part touches, and presses said mirror with elastic force toward said second receiving part.

3. An optical device according to claim 2 , further comprising:

a supporting part which supports a face of said mirror on which own weight of said mirror acts.

4. An optical device according to claim 3 , wherein

a contact zone of said supporting part and said mirror is lubricated by a lubricant.

5. An optical device according to claim 1 , wherein

said two first receiving parts are installed such that they are located between said two first pressing parts sandwiching said mirror.

6. An optical device according to claim 3 , further comprising:

an elastic pushing part which presses said mirror with elastic force in a direction toward said supporting part.

7. An optical device according to claim 6 , wherein

said elastic pushing part comprises: a spring member which pushes said mirror; and an elastic member installed between said spring member and said mirror.

8. An optical device according to claim 6 , wherein

a force which said second pressing part pushes said mirror toward said second receiving part and a force which said elastic pushing part pushes said mirror toward said supporting part are in proportional relation.

9. An adjusting method for an optical device equipped with a mirror which reflects light, comprising:

a procedure for sandwiching one of ends in a lengthwise direction of said mirror with a plurality of first receiving parts and a plurality of first pressing parts;

a procedure for sandwiching an other end of said mirror with one second receiving part and one second pressing part;

a procedure for supporting a face of said mirror on which own weight of said mirror acts; and

a procedure for pressing said mirror in a direction toward said supporting part, wherein

two among said first receiving parts and two among said first pressing parts are set up separately each other respectively, and said two first pressing parts are installed such that they are located between said two first receiving parts sandwiching said mirror, and

one of a force which said second pressing part pushes said mirror toward said second receiving part and a force which said elastic pushing part pushes said mirror toward said supporting part is adjusted such that they are in proportional relation.

10. An optical device equipped with a mirror which reflects light, comprising:

a plurality of first receiving means for receiving one face of one of ends in a lengthwise direction of said mirror; and

a plurality of first pressing means for touching a face opposing to said face to which said first receiving means touch, and pressing said mirror with elastic force toward said first receiving means, wherein

two among said first receiving means and two among said first pressing means are set up separately each other respectively, and said two first pressing means are installed such that they are located between said two first receiving means sandwiching said mirror.

11. An optical device according to claim 10 , further comprising:

one second receiving means for receiving one face in an other end of said mirror; and

one second pressing means for touching a face opposing to said face to which said second receiving means touches, and presses said mirror with elastic force toward said second receiving means.

12. An optical device according to claim 11 , further comprising:

a supporting part means for supporting a face of said mirror on which own weight of said mirror acts.

13. An image reading apparatus which reads image information on a manuscript, comprising:

a platen on which said manuscript is placed;

an optical device having a plurality of first receiving parts that touch one face of one of left and right ends in a lengthwise direction of said mirror, and a plurality of first pressing parts that touch a face opposing to said face to which said first receiving parts touch, and press said mirror with elastic force toward said first receiving parts; and

an optical device moving mechanism which moves said optical device in a predetermined direction when reading said manuscript, wherein

two among said first receiving parts and two among said first pressing parts are set up separately each other respectively, and said two first pressing parts are installed such that they are located between said two first receiving parts sandwiching said mirror.

14. An image reading apparatus which reads image information on a manuscript according to claim 13 , wherein

said optical device comprises: one second receiving part which touches one face in an other end of said mirror; and

a second pressing part that touches a face opposing to said face to which said second receiving part touches, and presses said mirror with elastic force toward said second receiving part.