JPH0641965Y2 - Discharge sheet stacking device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial Field of the Invention The present invention relates to a discharge sheet stacking device such as a copying machine or a printer.

2. Description of the Related Art Ejected sheet stacking apparatuses are used in many places where image-formed sheets are ejected and collected in an image forming apparatus such as a printer or a copying machine. Sheet stacking devices are generally configured to receive discharged sheets from the discharge rollers or chutes of the device and various types have been proposed.
For example, it may be of the simple receiving type, or may have a stack support surface for indicating a stack of stacked sheets, said support surface for holding the top of the stack being formed at a substantially constant height. There is also proposed a type in which the can be raised and lowered.

Further, JP-A-59-26855 discloses a discharged sheet stacking device having a braking roll (damper roll).
In the discharged sheet stacking device described in this publication, a damper roll having a large friction coefficient between the contacting sheets is rotated by its own weight to the discharged sheet on the tray to brake the sheet. In order to prevent the sheet from bouncing, the damper roll is combined with a pawl and ratchet or a one-way clutch in order to prevent the sheet from bouncing while aligning the front edge of the sheet with the alignment stopper provided at right angles to the sheet ejection direction It is constructed by providing a reverse rotation prevention mechanism such as.

Problems to be Solved by the Invention However, in the discharge sheet stacking device described in the above-mentioned publication, since the reverse rotation prevention mechanism is provided in the damper roll, there is a problem that the mechanism becomes complicated and the sheet size changes. In this case, since the position of the damper roll is fixed, depending on the sheet size, even if the leading edge of the sheet contacts the alignment stopper, the trailing edge of the sheet may still be nipped by the discharge roller pair. In this case, the sheet will be curled,
There was a problem that it was not possible to flexibly adapt to the sheet size.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a discharged sheet stacking device capable of flexibly coping with a change in sheet size with a simple mechanism.

Means for Solving the Problems An alignment stopper for aligning the leading edge of the sheet is attached to the discharge tray so as to be movable according to the sheet size. Further, by mounting a braking roller that is in rotational contact with the top surface of the sheet that is being discharged and accumulated by the discharging roller pair so as to be movable while keeping a constant distance from the alignment stopper, Solve the problem of.

Action The braking roller is ejected by the ejection roller and is rotationally contacted with the top surface of the sheet while being accumulated, whereby the movement of the sheet is braked, and the leading edge of the sheet abuts the alignment stopper lightly and stops. When the size of the ejected sheet is changed, the alignment stopper and the braking roller are moved together without changing the distance between them, so that the sheet can be curled or the like without causing a problem such as curling. It is possible to flexibly deal with stacking.

Embodiment Hereinafter, the present invention will be described in detail based on an embodiment shown in the drawings.

Referring to FIG. 1, there is shown a schematic side view of an embodiment of the present invention, which is an apparatus main body 10 such as a copying machine or a printer.
A discharge roller pair 12 is provided below the shafts, and each roller has a shaft 12a, 12b as shown in the schematic plan view of FIG.
The sheet is conveyed by rotating one of them by a rotation driving means (not shown) and the other by being driven to rotate. A discharge tray 14 is provided so as to be inclined so as to descend in the sheet entry direction in order to help the sheet 15 enter the tray 14. At the tip of the discharge tray 14, an alignment stopper extending from the discharge tray 14 in a direction perpendicular to the upright sheet discharge direction is provided.
16 is provided so as to be movable and adjustable with respect to the discharge tray 14. The alignment stopper 16 is attached to the discharge tray 14 by a known means so that it can be adjusted in three stages according to the sheet size of B5, A4, B4, for example.

Reference numeral 18 denotes a sheet guide plate, which is bifurcated as shown in FIG.
Are fixed, and the bracket 20 is provided with an elongated hole 22. Braking roll (damper roll) in this slot 22
The shaft 24a of 24 is fitted, the damper roll 24 is supported so as to be movable in the vertical direction, and comes into contact with the discharge sheet 15 by its own weight. Damper roll 24,
For example, it is formed of a material having a high coefficient of friction with the sheet 15 such as chloroprene rubber. A base end portion 18a of the sheet guide plate 18 is slidably mounted on a slide rail 26 provided in the apparatus main body 10, and a roller 28 is rotatably provided at a tip end portion thereof.

The distance between the discharge roller pair 12 and the damper roller 24 is the sheet
The positional relationship is set so that the front edge of the roller 15 sunk into the lower portion of the damper roll 24 before the roller 15 leaves the nip of the discharge roller pair 12. Further, the sheet guide plate 18 guides the sheet 15 so that the front edge of the sheet 15 leaves the pair of discharge rollers 12 after the leading edge of the sheet 15 and surely sinks between the damper roll 24 and the tray 14, and the damper roll is provided by the slot 22. It has the function of holding 24 while allowing it to move up and down.

The operation of this embodiment configured as described above will be described below.

In a sheet discharging unit such as a high speed printer, the sheet conveying speed of the discharging roll pair 12 is about 1 m / sec. The sheet 15 discharged at such a high speed has the front edge thereof sunk between the damper roll 24 and the discharge tray 14 before leaving the conveyance nip of the discharge roller pair 12, so that the damper roll 24 is roughly the sheet 15. Start rotating at the same peripheral speed. As described above, since the damper roll 24 is made of chloroprene rubber or the like having a high friction coefficient with the sheet, the sheet 15
Hardly slips with the damper roll 24, so that the damper roll 24 starts to rotate at substantially the same peripheral speed as the seat 15. For example, damper roll 24
Is 11 g, the damper roll is formed so that the friction coefficient between the damper roll 24 and the seat 15 is μ = 1 to 1.1, and two damper rolls are arranged in parallel as shown in the figure. It was confirmed to be effective.

After passing under the damper roll 24, the sheet 15 is conveyed to the alignment stopper 16 while being braked by the damper roll 24, but when the front edge of the sheet 15 collides with the alignment stopper 16, it tries to jump back. However, since the damper roll 24 rotates in the sheet conveying direction at a high speed to some extent, the sheet 15
Is restricted by its inertial force and its movement in the bounce direction is restricted, so that the leading edge of the sheet 15 stops at the position of the alignment stopper 16.

The height of the stack increases as the sheets are stacked (stacked), but since the damper roll 24 can be moved in the vertical direction by the long hole 22 provided in the sheet guide plate 18, the self-weight of the damper roll 24 is always constant. Acts on seat 15. Weighing 64
g / m ² of B5, A4, B4 fine paper, and was a long-side feed of a sheet weighing 132.5 g / m ² of A4, hardly it is跳返Ri from the alignment stopper 16 of the seat 15 in the condition Was confirmed.

Also, because two damper rolls 24 are arranged in parallel,
The rotation of the sheet 15 on the discharge tray 14 can be prevented, and as a result, the disturbance of the sheet 15 in the short side direction can be suppressed.

If the ejected sheet size is different, the alignment stopper
16 is moved to the position of 16 'or 16 ". When the alignment stopper 16 is moved in this manner, one end 18a of the sheet guide plate 18 is moved.
Is slidably mounted on the sliding rail 26,
In combination with the inclination of the discharge tray 14, the sheet guide plate 18 moves to the right in the figure while the roller 28 provided at the leading end of the sheet guide plate 18 is brought into contact with the alignment stopper 16. As a result,
The damper roller 24 attached to the sheet guide plate 18 is also moved to the right without changing the distance from the alignment stopper 16. As a result, even if the sheet size is changed,
The damper roll 24 can be kept at a constant distance from the alignment stopper 16.

Another method for keeping the distance between the damper roll 24 and the alignment stopper 16 constant is to use the damper roll 24 as a sheet guide plate.
By mounting it on the alignment stopper 16 via a bracket instead of mounting it on 18, it is possible to keep the distance between the damper roll 24 and the alignment stopper 16 constant even if the alignment stopper 16 is moved.

There are a center registration method as shown in FIG. 3 and a corner registration method as shown in FIG. 4 depending on the copying machine printer and the like, but for general high-quality paper weighing 64 g / m ^2. It has been confirmed by experiments that the discharged sheet stacking device of the present invention is sufficiently effective not only for center registration but also for corner registration paper feeders for B5, A4 and B4 size sheets. did it.

Effect of the Invention Since the present invention is configured as described above in detail, the reverse rotation prevention mechanism is not provided on the braking roller, and even when the discharged sheet size is different, the sheet is not curled or the like on the tray. It is possible to provide an ejected sheet stacking device capable of stacking sheets on the tray by surely aligning them with the provided alignment stopper.

[Brief description of drawings]

FIG. 1 is a schematic side view of an embodiment of the present invention, FIG. 2 is a schematic plan view in which the sliding rail is omitted in FIG. 1, FIG. 3 is an explanatory view of center registration, and FIG. It is explanatory drawing of a corner registration. 10 ... Device body, 12 ... Ejection roller pair, 14 ... Ejection tray, 15 ... Sheet, 16 ... Alignment stopper, 18 ... Sheet guide plate, 24 ... Damper roll, 26 ... Sliding roller, 28 ... Roller.

Claims (1)

[Scope of utility model registration request] 1. A braking roller that is in rotational contact with the top surface of a sheet that is being discharged and accumulated by a pair of discharging rollers,
In a discharged sheet stacking device that stacks discharged sheets on a tray by aligning the leading edges of the sheets with an alignment stopper arranged in a direction perpendicular to the sheet conveying direction, the alignment stopper is movable on the tray according to the sheet size. In addition, the sheet guide plate is attached to the main body of the apparatus such that the tip of the sheet guide plate is always in contact with the alignment stopper so as to be movable, and the braking roller is rotatably attached to a predetermined position of the sheet guide plate. Discharge sheet stacking device.