Patent ID: 9560226
Date: 2017-01-31
CPC Classifications: H04N

Claim:
1. An image reading apparatus comprising: an apparatus body having a document placement surface; a cover portion supported by the apparatus body so as to be pivotable between an open position where the document placement surface is uncovered and a closed position where the document placement surface is covered with the cover portion; a magnetic force generating portion configured to selectively generate a magnetic attraction force and a magnetic repulsion force between a pair of opposing members provided in the cover portion and the apparatus body, respectively; a magnetic force control portion configured to switch the magnetic force generating portion between a state where the magnetic force generating portion generates the attraction force and a state where the magnetic force generating portion generates the repulsion force; a guide portion configured to guide a permanent magnet along a vertical direction, the permanent magnet provided in the apparatus body so that the permanent magnet is displaceable between a first position opposing an electromagnet fixed to the cover portion and a second position lower than the first position; a detection portion configured to detect that the permanent magnet is located at at least one of the first position and the second position, the detection portion includes a light-emitting portion and a light-receiving portion, light emitted from the light-emitting portion is not blocked by the permanent magnet located at the first position, and light emitted from the light-emitting portion is blocked by the permanent magnet located at the second position; and a determination portion configured to determine whether the cover portion is at the open position or the closed position, based on a result of the detection of the detection portion, when the magnetic force generating portion is generating the attraction force; wherein the pair of opposing members of the magnetic force generating portion are the permanent magnet and the electromagnet, respectively, and the magnetic force control portion switches the magnetic force generating portion between the state where the magnetic force generating portion generates the attraction force and the state where the magnetic force generating portion generates the repulsion force, by changing a direction of a current supplied to the electromagnet.