Conveyor device and image forming apparatus

A conveyor device comprising:

• a support portion in which a through hole is formed and which is configured to support a to-be-conveyed medium;
• a negative pressure chamber configured to cause negative pressure to act on the to-be-conveyed medium through the through hole to suck the to-be-conveyed medium to the support portion;
• and
• a conveyance section configured to convey the to-be-conveyed medium sucked to the support portion,
• wherein the negative pressure chamber includes a wall in which a communication hole to communicate the negative pressure chamber with the air is formed,
• the conveyor device further comprising:
• a shutter configured to slide on the wall of the negative pressure chamber to open/close the communication hole;
• an opening/closing controller configured to control an opening/closing operation of the shutter;
• and
• a target sensor configured to detect the fact that a lead edge of the to-be-conveyed medium passes over a predetermined detection point located upstream of the support portion in a conveyance direction and detect the fact that a rear edge of the to-be-conveyed medium passes over the detection point,
• wherein the opening/closing controller drives to open the shutter when a first time period elapses from the time when the target sensor detects the fact that the lead edge of the to-be-conveyed medium passes over the detection point and drives to close the shutter when a second time period elapses from the time when the target sensor detects the fact that the rear edge of the to-be-conveyed medium passes over the detection point.