Image forming apparatus

1. An image forming apparatus comprising:

an apparatus main body having a first surface and a second surface opposed in a first direction, and housing an image forming unit that outputs an image to a recording material;

a housing body for housing an image reading unit that optically reads a document, the housing body disposed on an upper surface side of the apparatus main body, and a first end of the housing body rotatably connected to the apparatus main body near the second surface,

the housing body rotatably displacing to

a closed position at which a second end of the housing body near to the first surface is disposed in closest proximity to the apparatus main body,

a fully open position at which the second end is most separated from the apparatus main body, and

an intermediate open position between the closed position and the fully open position;

a link member retaining the housing body, which has displaced to the fully open position, at the fully open position,

a first end of the link member connected rotatably to the housing body, and

the link member configured to reciprocally displace in the first direction so that a second end of the link member

is positioned in closest proximity to a first position near the first surface when the housing body is positioned at the closed position,

is positioned in closest proximity to a second position near the second surface when the housing body is positioned at the fully open position, and

is positioned at a third position between the first position and the second position when the housing body is positioned at the intermediate open position;

a guide portion formed to extend in the first direction on an upper side of the housing body, guiding the second end of the link member, and including a stopper formed near the second surface;

a suspended portion disposed on the guide portion near the second surface to reciprocally displace in the first direction,

the suspended portion positioned

at a restricted position in abutment with the stopper when the housing body is positioned at the closed position or the intermediate open position, and

at a non-restricted position near to the second surface and not in abutment with the stopper when the housing body is positioned at the fully open position;

a tension spring, one end of which is connected to the link member and the other end of which is connected to the suspended portion,

the tension spring

being in an extended state with the other end being disposed at a position corresponding to the restricted position when the housing body is positioned at the closed position,

being in a free-length state with the other end being disposed at the position corresponding to the restricted position when the housing body is positioned at the intermediate open position, and

being in a free-length state with the other end being disposed at a position corresponding to the non-restricted position closer to the second surface than the restricted position when the housing body is positioned at the fully open position, wherein

when the housing body displaces and rotates from the fully open position to the intermediate open position, the tension spring displaces in the free-length state towards the first surface, and

when the housing body displaces and rotates from the intermediate open position to the closed position, the second end does not displace, and only the first end displaces towards the first surface, the tension spring shifts from the free-length state to the extended state.

2. An image forming apparatus according to comprising:

an apparatus main body having a first surface and a second surface opposed in a first direction, and housing an image forming unit that outputs an image to a recording material;

a housing body for housing an image reading unit that optically reads a document, the housing body disposed on an upper surface side of the apparatus main body, and a first end of the housing body rotatably connected to the apparatus main body near the second surface,

the housing body rotatably displacing to

a closed position at which a second end of the housing body near to the first surface is disposed in closest proximity to the apparatus main body,

a fully open position at which the second end is most separated from the apparatus main body, and

an intermediate open position between the closed position and the fully open position;

a link member retaining the housing body, which has displaced to the fully open position, at the fully open position,

a first end of the link member connected rotatably to the housing body, and

the link member configured to reciprocally displace in the first direction so that a second end of the link member

is positioned in closest proximity to a first position near the first surface when the housing body is positioned at the closed position,

is positioned in closest proximity to a second position near the second surface when the housing body is positioned at the fully open position, and

is positioned at a third position between the first position and the second position when the housing body is positioned at the intermediate open position;

a guide portion formed to extend in the first direction on an upper side of the housing body, guiding the second end of the link member, and including a stopper formed near the second surface;

a suspended portion disposed on the guide portion near the second surface to reciprocally displace in the first direction,

the suspended portion positioned

at a restricted position in abutment with the stopper when the housing body is positioned at the closed position or the intermediate open position, and

at a non-restricted position near to the second surface and not in abutment with the stopper when the housing body is positioned at the fully open position;

a tension spring, one end of which is connected to the link member and the other end of which is connected to the suspended portion,

the tension spring

being in an extended state with the other end being disposed at a position corresponding to the restricted position when the housing body is positioned at the closed position,

being in a free-length state with the other end being disposed at the position corresponding to the restricted position when the housing body is positioned at the intermediate open position, and

being in a free-length state with the other end being disposed at a position corresponding to the non-restricted position closer to the second surface than the restricted position when the housing body is positioned at the fully open position, wherein

when the housing body displaces and rotates from the fully open position to the intermediate open position, the tension spring is displaced in the free-length state towards the first surface together with the suspended portion that is connected to the second end since the first end is displaced towards the first surface by the link member, and

when the housing body displaces and rotates from the intermediate open position to the closed position, a displacement of the second end towards the first surface is restricted by the suspended portion, the first end is displaced further towards the first surface by the link member, and the tension spring shifts from the free-length state to the extended state.

3. The image forming apparatus according to claim 1 , further comprising a restricting portion for restricting the link member that is disposed at the second position from moving towards the first surface, when the housing body is positioned at the fully open position.

4. The image forming apparatus according to claim 1 further comprising an outer wall member, wherein

the outer wall member is disposed between the apparatus main body and the housing body, connected to the apparatus main body to rotate to a non-exposure position at which an inner portion of the apparatus main body is not exposed and an exposure position at which the inner portion of the apparatus main body is exposed, and connected to the housing body to displace and rotate in response to displacement and rotation of the housing body, and

the outer wall member is configured so that a rotation angle of the outer wall member is greater than a rotation angle of the housing body when the housing body is in the full open position.

5. The image forming apparatus according to claim 2 , further comprising a restricting portion for restricting the link member that is disposed at the second position from moving towards the first surface, when the housing body is positioned at the fully open position.

6. The image forming apparatus according to claim 2 further comprising an outer wall member, wherein

the outer wall member is disposed between the apparatus main body and the housing body, connected to the apparatus main body to rotate to a non-exposure position at which an inner portion of the apparatus main body is not exposed and an exposure position at which the inner portion of the apparatus main body is exposed, and connected to the housing body to displace and rotate in response to displacement and rotation of the housing body, and

the outer wall member is configured so that a rotation angle of the outer wall member is greater than a rotation angle of the housing body when the housing body is in the fully open position.