Sheet stacking apparatus and image forming apparatus

An image forming apparatus comprising:

• an image forming unit configured to form an image on a sheet;
• an apparatus main body provided with the image forming unit;
• a door pivotable about a pivot relative to an apparatus main body;
• a sheet stacking unit provided in the door, wherein the sheet stacking unit includes a sheet stacking surface onto which sheets are to be stacked, and wherein one end of the sheet stacking surface is located higher than the other end of the sheet stacking surface in a state in which the door is at a closure position, and the one end of the sheet stacking surface can be located lower than the other end of the sheet stacking surface in a state in which the door is opened from the closure position;
• and
• a resistance application unit configured to apply resistance against the pivot of the door being moved to be opened,
• wherein the resistance application unit is configured to apply no resistance to the pivot of the door which is at any position in a first area, and to apply resistance to the pivot of the door which is at any position in a second area,
• wherein the first area is between the closure position and a first position where the door pivots from the closure position by a first angle, and the second area is an area where the door pivots to be opened over the first position,
• wherein, in a state in which the door is at the closure position, a centroid of the door is located on a first side of a vertical line passing through a center of the pivot,
• wherein, when the centroid of the door is located on the vertical line passing through the center of the pivot, the door is in the first area,
• wherein, in a state in which the door is at the first position, the one end of the sheet stacking surface is located higher than the other end of the sheet stacking surface and the centroid of the door is located on a second side of the vertical line passing through the center of the pivot and a self-weight of the door acts on the door in a direction moving from the first position to the second area,
• wherein, in a state in which the door is at a second position in the second area, the sheet stacking surface is horizontal, and
• wherein, in a state in which the door is at a third position in the second area, the one end of the sheet stacking surface is located lower than the other end of the sheet stacking surface.

A sheet stacking apparatus comprising:

• a door pivotable about a pivot relative to an apparatus main body;
• a sheet stacking unit provided in the door, wherein the sheet stacking unit includes a sheet stacking surface onto which sheets are to be stacked, and wherein one end of the sheet stacking surface is located higher than the other end of the sheet stacking surface in a state in which the door is at a closure position, and the one end of the sheet stacking surface can be located lower than the other end of the sheet stacking surface in a state in which the door is opened from the closure position;
• and
• a resistance application unit configured to apply resistance against the pivot of the door being moved to be opened,
• wherein the resistance application unit is configured to apply no resistance to the pivot of the door which is at any position in a first area, and to apply resistance to the pivot of the door which is at any position in a second area,
• wherein the first area is between the closure position and a first position where the door pivots from the closure position by a first angle, and the second area is an area where the door pivots to be opened over the first position,
• wherein, in a state in which the door is at the closure position, a centroid of the door is located on a first side of a vertical line passing through a center of the pivot,
• wherein, when the centroid of the door is located on the vertical line passing through the center of the pivot, the door is in the first area,
• wherein, in a state in which the door is at the first position, the centroid of the door is located on a second side of the vertical line passing through the center of the pivot and a self-weight of the door acts on the door in a direction moving from the first position to the second area,
• wherein, in a state in which the door is at the first position where the door pivots from the closure position by the first angle, the sheet on the sheet stacking surface does not move, along the sheet stacking surface, to the one end side of the sheet stacking surface by weight of the sheet, and
• wherein, in a state in which the door is at a second position in the second area, the sheet on the sheet stacking surface can move, along the sheet stacking surface, to the one end side of the sheet stacking surface by weight of the sheet.