Sheet stacking apparatus, sheet processing apparatus, and image forming system

A sheet stacking apparatus, comprising:

• a placement portion on which a sheet is placed;
• a conveyance portion configured to convey a sheet placed on the placement portion;
• a regulation portion configured to regulate a position of a sheet conveyed by the conveyance portion through contact with the sheet;
• a pressing portion configured to press a sheet regulated in position by the regulation portion, the pressing portion being configured to press a sheet regulated in position by the regulation portion at a pressing position, the pressing portion being configured to press a sheet which is being conveyed by the conveyance portion and is not in contact with the regulation portion at the pressing position;
• and
• a support member configured to support the pressing portion in a movable manner in a thickness direction of a sheet placed on the placement portion and a conveyance direction in which the conveyance portion conveys a sheet,
• wherein the support member includes four-bar connecting members constructing a parallel link mechanism.

A sheet stacking apparatus, comprising:

• a placement portion on which a sheet is placed;
• a conveyance portion configured to convey a sheet placed on the placement portion;
• a regulation portion configured to regulate a position of a sheet conveyed by the conveyance portion through contact with the sheet;
• a pressing member configured to press a sheet regulated in position by the regulation portion, the pressing member comprising a pressing portion and a guide portion, the pressing portion being configured to move integrally with the guide portion, the pressing portion being configured to press a sheet regulated in position by the regulation portion at a first pressing position and a second pressing position, the second pressing position being spaced apart from the placement portion in a thickness direction of a sheet placed on the placement portion by a distance which is longer than a distance between the placement portion and the first pressing position, the pressing portion being configured to press a sheet which is being conveyed by the conveyance portion and is not in contact with the regulation portion at the first pressing position, and the pressing portion being configured to press a sheet which is being conveyed by the conveyance portion and is not in contact with the regulation portion at the second pressing position, the guide portion being located at a position opposite to the regulation portion across the pressing portion in a conveyance direction in which the conveyance portion conveys a sheet and being configured to guide a sheet to be conveyed to the regulation portion;
• and
• a support member configured to support the pressing member such that a whole of the pressing member moves in the thickness direction and the conveyance direction, the pressing portion moving to a position corresponding to the first pressing position and a position corresponding to the second pressing position by being supported by the support member, the guide portion moving to a first position and a second position by being supported by the support member, the guide portion being positioned at the first position in a case that the pressing portion presses a sheet at the first pressing position, the guide portion being positioned at the second position in a case that the pressing portion presses a sheet at the second pressing position, a distance between the guide portion located at the first position and the regulation portion in the conveyance direction being longer than a distance between the guide portion located at the second position and the regulation portion in the conveyance direction.

A sheet stacking apparatus, comprising:

• a placement portion on which a sheet is placed;
• a conveyance portion configured to convey a sheet placed on the placement portion;
• a regulation portion configured to regulate a position of a sheet conveyed by the conveyance portion through contact with the sheet;
• a pressing portion configured to press a sheet regulated in position by the regulation portion, the pressing portion being configured to press a sheet regulated in position by the regulation portion at a pressing position, the pressing portion being configured to press a sheet which is being conveyed by the conveyance portion and is not in contact with the regulation portion at the pressing position;
• and
• a support member configured to support the pressing portion in a movable manner in a thickness direction of a sheet placed on the placement portion and a conveyance direction in which the conveyance portion conveys a sheet, the support member being configured to be rotatable about a first axis and supporting the pressing portion such that the pressing portion rotates about a second axis different from the first axis.