Meidum passage switching mechanism disposed on a casing of an image forming device and related image forming device

An image forming device comprising:

• a casing, an entrance passage, a first exit passage and a second exit passage being formed inside the casing;
• and
• a medium passage switching mechanism disposed on the casing and for guiding a medium to enter into the first exit passage or the second exit passage from the entrance passage, the medium passage switching mechanism comprising:
• a medium tray pivotally connected to the casing and pivotally switchable between a first position and a second position;
• a guiding component pivotally connected to the casing and pivotally switchable between a third position and a fourth position;
• and
• at least one resilient component abutting against the guiding component;
• wherein when the medium tray pivots relative to the casing from the first position to the second position along a first pivoting direction, the medium tray does not contact with the guiding component, so that the guiding component is driven by the at least one resilient component to pivot relative to the casing from the third position to the fourth position along the first pivoting direction, when the guiding component is located at the fourth position, the guiding component guides the medium to enter into the second exit passage from the entrance passage, when the medium tray pivots relative to the casing from the second position to the first position along a second pivoting direction opposite to the first pivoting direction, the medium tray abuts against the guiding component to drive the guiding component to pivot relative to the casing from the fourth position to the third position along the second pivoting direction and to compress the at least one resilient component, and when the guiding component is located at the third position, the guiding component guides the medium to enter into the first exit passage from the entrance passage.