BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a stacking device on which sheets are stacked and which is provided in an image forming apparatus or a sheet post-processing device mounted in the image forming apparatus.

Description of the Related Art

Conventionally, a discharged sheet stacking unit on which sheets as recording materials are stacked is provided in an image forming apparatus or a sheet post-processing device as a stacking device. The discharged sheet stacking unit includes a sheet stacking unit on which sheets are stacked and a conveying unit that discharges sheets onto the sheet stacking unit. As an example of a stacking device, a device in which a rear end wall provided on an upstream end side (a sheet rear end side) in a conveying direction of stacked sheets is integrated with a sheet stacking unit and can be separated from a conveying unit is known. This configuration is effective in creating a space for users to access a jammed sheet during clearing of a paper jam, for example. Japanese Patent Application Publication No. 2002-274727 discloses a stacking device which further includes an abutting member as a configuration that abuts on a sheet stacked on a sheet stacking unit in addition to the rear end wall and the sheet stacking unit which are integrated. This abutting member is configured to abut on a sheet stacked on the sheet stacking unit from an upper side so that a sheet abutting position changes according to the height of the stacked sheet. However, in the device configuration disclosed in Japanese Patent Application Publication No. 2002-274727, when the sheet stacking unit and the rear end wall are separated from the conveying unit during clearing of a paper jam so as to return to original positions, the rear end wall and the abutting member interfere with each other. Therefore, in Japanese Patent Application Publication No. 2002-274727, a cam shape is provided in a portion of the rear end wall making contact with the abutting member to avoid interference so that the abutting member moves along the cam shape when the rear end wall returns to the original position. However, since the abutting member moves in a state of continuously making contact with the cam shape, when there is an impact (for example, when the rear end wall returns to the original position with great power), the abutting member may be broken without following the cam shape.

SUMMARY OF THE INVENTION

However, a stacking device which includes a detection flag for detecting the height of a sheet stacked on a sheet stacking unit, for example, in addition to a sheet pressing member as a configuration that presses sheets stacked on the sheet stacking unit is known. The detection flag is also configured so that the sheet abutting position changes according to the height of a stacked sheet similarly to the sheet pressing member. Therefore, when the sheet stacking unit and the rear end wall are separated from the conveying unit so as to return to the original positions during clearing of a paper jam, problems similar to those of a device having the sheet pressing member occur.

Therefore, the present invention has been made in view of such a situation. That is, an object of the present invention is to provide a stacking device which can be detachably attached to an image forming apparatus body without breaking an abutting member that abuts on a recording material stacked on the stacking device even when an operation of pulling or returning the stacking device with great power when the stacking device is attached to or detached from the apparatus body.

In order to attain the object, a stacking device, which is detachably attached to an apparatus body of an image forming apparatus including the apparatus body having an abutting member that abuts on a stacked recording material and on which a recording material discharged from the apparatus body is stacked, according to the present invention includes:

a first supporting unit that supports the recording material from a lower side of the recording material; and

a second supporting unit that supports an end of the recording material in an attachment/detachment direction which is a direction in which the stacking device is attached to and detached from the apparatus body,

wherein the second supporting unit includes a corresponding region, and a position of the corresponding region agrees with a position of the abutting member abut with the recording material in a width direction which is orthogonal to the attachment/detachment direction, and

wherein at least a height of the corresponding region in a direction orthogonal to the attachment/detachment direction and the width direction is lower than a height of the abutting member.

In order to attain the object, an image forming apparatus according to the present invention includes:

an image forming unit that forms an image on a recording material;

the stacking device described above, and

an abutting member that abuts on the recording material stacked on the stacking device.

In order to attain the object, an image forming apparatus according to the present invention includes:

an image forming unit that forms an image on a recording material;

a stacking device on which the recording material on which an image is formed by the image forming unit is stacked and which is detachably attached to an apparatus body of the image forming apparatus, the stacking device including a first supporting unit that supports the recording material from a lower side of the recording material and a second supporting unit that supports an end of the recording material in an attachment/detachment direction in which the stacking device is attached to and detached from the apparatus body;

a control unit that controls conveying of the recording material in the image forming apparatus;

a first abutting member that abuts on the recording material stacked on the stacking device and is configured such that an abutting position of abutting on the recording material stacked on the stacking device changes according to a height of the stacked recording materials; and

a second abutting member that abuts on the recording material stacked on the stacking device and is configured such that an abutting position of abutting on the recording material stacked on the stacking device is located closer to the end supported by the second supporting unit than the abutting position between the first abutting member and the recording material and changes according to the height of the stacked recording materials,

wherein the control unit performs control so that conveying of the recording material to the stacking device is stopped when either one of the first abutting member or the second abutting member abuts on the recording material at a maximum height position at which the recording material can be supported by the second supporting unit in a direction orthogonal to the attachment/detachment direction and the width direction of the recording material.

According to the present invention, it is possible to provide a stacking device which can be detachably attached to an image forming apparatus body without breaking an abutting member that abuts on a recording material stacked on the stacking device even when an operation of pulling or returning the stacking device with great power when the stacking device is attached to or detached from the apparatus body.

Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings.

