Sheet detection device and image forming apparatus

An image forming apparatus comprising:

• a sheet detection device;
• and
• an image forming unit configured to form an image on a sheet by using an image forming condition based on a feature amount of the sheet measured by a measurement unit,
• wherein the sheet detection device comprises:
• a measurement unit for measuring a feature amount of a sheet conveyed by a conveyance unit;
• a pressing member movable between a first position separated from the measurement unit and a second position closer to the measurement unit than the first position;
• and
• a moving unit configured to move the pressing member,
• wherein the pressing member is arranged by the moving unit at the first position in a case where the measurement unit detects that the sheet has not been conveyed to a measurement position of the measurement unit,
• wherein the moving unit is configured to move the pressing member from the first position to the second position in a case where the measurement unit detects that the sheet has been conveyed to the measurement position of the measurement unit, and
• wherein the measurement unit is configured to measure the feature amount of the sheet under a state in which the pressing member is arranged at the second position.