Image reading apparatus and image forming apparatus including the same

1. An image reading apparatus, comprising: a placing member on which an original is to be placed, the placing member including an opposite surface which is opposite to a surface of the placing member that contacts the original; a reading unit movable to a position opposed to the original across the placing member and constructed to read an image of the original placed on the placing member by receiving light reflected off the original via the placing member; a casing constructed to support an outer peripheral edge portion of the placing member; the opposite surface of the placing member includes a portion through which a light to be received by the reading unit passes when the reading unit reads the image of the original; and a support member that supports a portion of the opposite surface other than the outer peripheral edge portion of the placing member, the support member is further constructed to include an abutment portion abutting against the casing, such that the support member supports the placing member when the abutment portion abuts against the casing.

2. An image reading apparatus according to claim 1 , wherein the reading unit has an abutment portion abutting against the casing so that the reading unit is supported by the casing, the abutment portion of the reading unit being different from the abutment portion of the support member.

3. An image reading apparatus according to claim 1 , wherein the support member is movable between a support position capable of supporting the placing member and a retracted position retracted from the placing member relative to the support position.

4. An image reading apparatus according to claim 3 , wherein the reading unit is configured to read the image of the original while moving, and when the support member is situated in the support position, the support member restricts movement of the reading unit, and when the support member is situated in the retracted position, the support member avoids restricting the movement of the reading unit.

5. An image reading apparatus according to claim 3 , further comprising a restricting member movable between a restricting position for restricting movement of the reading unit and a restriction canceling position for canceling the restriction, the restricting member moving from the restricting position to the restriction canceling position in association with movement of the support member from the support position to the retracted position.

6. An image reading apparatus according to claim 5 , wherein the support member and the restricting member are configured to move integrally.

7. An image reading apparatus according to claim 1 , wherein the support member is configured to move in a direction parallel to a placing surface of the placing member, on which the original is to be placed, in association with movement of the reading unit.

8. An image reading apparatus according to claim 7 , wherein the support member is movable relative to the reading unit in a normal direction to the placing surface.

9. An image reading apparatus according to claim 7 , wherein the support member is separated from the placing member under a state in which the placing member is not distorted.

10. An image reading apparatus according to claim 7 , wherein the support member is separated from the casing under a state in which the placing member is not distorted.

11. An image reading apparatus according to claim 1 , wherein the reading unit is separated from the placing member under a state in which the support member supports the placing member.

12. An image reading apparatus according to claim 7 , wherein the support member has a bending portion which is freely bendable, the bending portion having one end coupled to the reading unit, and having another end coupled to the casing, the bending portion being bendable in association with the movement of the reading unit.

13. An image reading apparatus according to claim 12 , wherein the bending portion has a signal line bundle connected to the reading unit.

14. An image reading apparatus according to claim 1 , wherein the support member is a rotary member which is rotatable and movable in a moving direction of the reading unit.

15. An image reading apparatus according to claim 3 , wherein when the support member moves from the retracted position to the support position, a part of the support member which abuts against the placing member moves in a normal direction to a placing surface of the placing member, on which the original is to be placed.

16. An image reading apparatus according to claim 3 , wherein when a power of the image reading apparatus is turned ON under a state in which the support member is situated at the support position, the support member moves to the retracted position.

17. An image reading apparatus according to claim 3 , wherein the support member moves from the support position to the retracted position in association with an operation in which a protective member placed on a main body of the image reading apparatus and protecting the image reading apparatus is removed from the main body.

18. An image reading apparatus according to claim 1 , wherein the support member supports a center portion of the opposite surface of the placing member in a moving direction of the reading unit and a direction orthogonal to the moving direction.

19. An image reading apparatus according to claim 1 , wherein a part of the support member which abuts against the placing member is an elastic portion.

20. An image reading apparatus according to claim 1 , further comprising an image forming unit for forming an image on a recording material based on information of an image of an original, which is read by the reading unit.