Sheet loading apparatus and image forming apparatus

A sheet loading apparatus for carrying a sheet loaded in a first tray to a second tray downstream of the first tray in a sheet feed direction, the sheet loading apparatus comprising:

• a grip portion configured to grip the sheet loaded in the first tray;
• a sliding portion configured to move the grip portion parallel to a sheet loading surface of the first tray between a sheet gripping position at an upstream end of the first tray in the sheet feed direction and a sheet release position at a downstream end in the sheet feed direction;
• a lift portion configured to move the grip portion via the sliding portion and cause the grip portion to emerge from the sheet loading surface of the first tray;
• and
• a common power transmission portion configured to transmit power to both the sliding portion and the lift portion, wherein
• in one cycle during which the grip portion is moved from the gripping position to the release position of a sheet and then back to the gripping position, after the sliding portion moves the grip portion from the gripping position of a sheet to a downstream side in the sheet feed direction, the lift portion moves the grip portion downward of the sheet loading surface of the first tray and in a direction in which the grip portion is inclined toward an upstream side in the sheet feed direction with respect to the sheet loading surface to cause the grip portion to reach the release position of a sheet, and after the sliding portion moves the grip portion concealed below the sheet loading surface of the first tray to the upstream side in the sheet feed direction, the lift portion moves the grip portion to the gripping position above the sheet loading surface of the first tray in a direction forming a substantially right angle to the sheet loading surface,
• wherein the sliding portion includes
• a plurality of engagement members supported by the grip portion and placed, side by side, in the sheet feed direction,
• a rail member having a guide portion extending parallel to the sheet loading surface of the first tray to movably engage with the plurality of engagement members along the sheet feed direction,
• a crank portion, having a crank shaft extending in the direction intersecting with the sheet feed direction and a crank pin extending away from and parallel to the crank shaft, to be rotatable about the crank shaft in a plane extending in the sheet feed direction and an up-and-down direction, and
• a crank arm having a first arm member whose lower end is rotatably supported via a support shaft parallel to the crank shaft and a second arm member attached at an upper end to the grip portion to be displaced relatively to the first arm member, the second arm member having a groove portion movably engaging with the crank pin.

A sheet loading apparatus for carrying a sheet loaded in a first tray to a second tray downstream of the first tray in a sheet feed direction, the sheet loading apparatus comprising:

• a grip portion configured to grip the sheet loaded in the first tray;
• a sliding portion configured to move the grip portion parallel to a sheet loading surface of the first tray between a sheet gripping position at an upstream end of the first tray in the sheet feed direction and a sheet release position at a downstream end in the sheet feed direction;
• a lift portion configured to move the grip portion via the sliding portion and cause the grip portion to emerge from the sheet loading surface of the first tray;
• and
• a common power transmission portion configured to transmit power to both the sliding portion and the lift portion, wherein
• in one cycle during which the grip portion is moved from the gripping position to the release position of a sheet and then back to the gripping position, after the sliding portion moves the grip portion from the gripping position of a sheet to a downstream side in the sheet feed direction, the lift portion moves the grip portion downward of the sheet loading surface of the first tray and in a direction in which the grip portion is inclined toward an upstream side in the sheet feed direction with respect to the sheet loading surface to cause the grip portion to reach the release position of a sheet, and after the sliding portion moves the grip portion concealed below the sheet loading surface of the first tray to the upstream side in the sheet feed direction, the lift portion moves the grip portion to the gripping position above the sheet loading surface of the first tray in a direction forming a substantially right angle to the sheet loading surface,
• wherein the lift portion includes
• a cam portion configured to be rotatable about a cam shaft extending in a direction intersecting with the sheet feed direction in a plane extending in the sheet feed direction and an up-and-down direction,
• a follower member configured to be able to oscillate about a support shaft extending parallel to the cam shaft, following the cam shape of the cam portion, and
• a link mechanism connected between the sliding portion and the follower member to move the sliding portion in the up-and-down direction in step with the oscillation of the follower member.