Image reading apparatus and image forming apparatus

An image reading apparatus comprising:

• a sheet conveyance portion configured to convey a sheet;
• an image reading portion comprising a movable portion and an image sensor and configured to read an image on the sheet conveyed by the sheet conveyance portion, the movable portion comprising a light source and being movable in a movement direction, the image sensor being configured to photoelectrically convert reflection light emitted from the light source and reflected on the sheet;
• and
• a first opening/closing unit configured to openably and closeably support the sheet conveyance portion with respect to the image reading portion,
• the first opening/closing unit being provided at, in the movement direction, a position a first distance from a center of gravity of the sheet conveyance portion;
• and
• a second opening/closing unit configured to openably and closeably support the sheet conveyance portion with respect to the image reading portion, the second opening/closing unit being provided at a position a second distance longer than the first distance from the center of gravity in the movement direction,
• wherein the first opening/closing unit comprises a first spring configured to urge the sheet conveyance portion in a direction in which the sheet conveyance portion moves from a closed position toward an opened position,
• wherein the second opening/closing unit comprises a second spring configured to urge the sheet conveyance portion in a direction in which the sheet conveyance portion moves from the closed position toward the opened position and an oil damper configured to attenuate vibration energy of the sheet conveyance portion, and
• wherein the first opening/closing unit does not comprise an oil damper.

An image reading apparatus comprising:

• a sheet conveyance portion configured to convey a sheet;
• an image reading portion configured to read an image on the sheet conveyed by the sheet conveyance portion at a reading position;
• a first support portion configured to support the sheet conveyance portion such that the sheet conveyance portion is pivotable about an axis with respect to the image reading portion, the first support portion comprising a first spring configured to urge the sheet conveyance portion in a direction in which the sheet conveyance portion moves from a closed position toward an opened position;
• and
• a second support portion configured to support the sheet conveyance portion such that the sheet conveyance portion is pivotable about the axis with respect to the image reading portion, the second support portion being provided in a position different from the first support portion in a direction along the axis and comprising a second spring configured to urge the sheet conveyance portion in the direction in which the sheet conveyance portion moves from the closed position toward the opened position,
• wherein a distance between the reading position and the first support portion in the direction along the axis is shorter than a distance between the reading position and the second support portion in the direction along the axis,
• wherein the second support portion comprises an oil damper that applies a resistance force against pivot of the sheet conveyance portion about the axis, and
• wherein the first support portion does not comprise an oil damper.