JPH0631121B2 - Paper ejection device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a sheet ejection device capable of always stably stacking sheets regardless of the stacking amount of ejected sheets.

[Conventional technology]

FIG. 2 shows an outline of a conventional general paper ejection device used in a recording device such as a copying machine.
It comprises a pinch roller 2 forming a pair with the paper discharge roller 1, and a paper discharge tray 3 arranged behind the both rollers. As is well known, in this paper discharge device, the paper discharge roller 1 is used.
On the other hand, the pinch roller 2 is rotatably pressed with a constant pressure so that the sheet 4 supplied from the left side of the drawing is gripped between the rollers with this pressure and driven by a driving means such as a motor. The discharge rollers 1 are conveyed in accordance with the rotation of the discharge rollers 1 and sequentially discharged and stacked (stacked) on the discharge tray 3. Needless to say, the most important issue in this type of paper ejection device is to stack the papers 4 ejected to the paper ejection tray 3 in a state in which the front, rear, left and right are precisely aligned and the curls and the like are corrected without unevenness. .

[Problems to be solved by the invention]

Now, assuming that the angle formed between the bottom surface of the paper ejection tray 3 and the paper ejection direction is the paper entry angle α with respect to the paper ejection tray 3, the paper stack performance and the paper stack amount in the paper ejection device of this type are The following can be said about the relationship.

For example, in order to shorten the time required for the discharged paper to stand still and stabilize, and to enhance the posture correction ability of the paper that is deformed in a curl shape, the paper plunge angle α is set to a relatively large value. Is desirable.

This method is certainly effective in improving the stack performance when the stack amount of paper is small, but when the stack amount increases, the fact that the paper plunge angle α is large as described above does not necessarily improve the stack performance. It will not contribute.

The main reason for this is that as the stack amount increases, the stack arrival position of newly discharged sheets with respect to the stacked sheets gradually approaches the discharge rollers.

That is, when the stack arrival position with respect to the paper discharge roller becomes gradually clogged as the stack amount increases, the influence of the succeeding discharged paper on the previously discharged paper 4 increases,
In particular, when the sheet plunge angle α is large, the sheet 4 is likely to buckle due to the trailing sheet ejected at a high angle.
In addition, rolling (paper curl) frequently occurs on the curled paper 4. Despite the existence of such a special relationship, the discharge roller 1,
In the above-mentioned conventional apparatus in which the pinch roller 2 and the paper ejection tray 3 are fixedly arranged and the paper ejection angle α with respect to the paper ejection tray 3 is constant, no matter how ideally the paper ejection angle α is set. There is a problem that the stack performance fluctuates significantly according to the stack amount.

[Means for solving problems]

The present invention has a support mechanism for press-contacting and supporting the pressure contact of the pinch roller with respect to the paper discharge roller so as to be movable, and a paper discharge means for discharging the paper in the contact direction of the pressure contact, and a discharge device The sheet ejection tray has a height that is displaced according to the stack weight of the sheets, and a transmission unit that transmits the height displacement of the sheet ejection tray to the support mechanism. The pressure contact of the roller pair is changed such that the discharge angle of the sheet with respect to the sheet discharge tray is gradually reduced in accordance with the height change of the sheet tray.

[Action]

In the present invention, the pressure contact of the roller pair is moved so that the stack weight of the sheets increases and the sheet discharge angle with respect to the sheet discharge tray gradually decreases as the sheet discharge tray moves downward. .

As a result, while the stack amount is small, it is possible to shorten the time required for the discharged sheets to remain stationary and to stabilize the posture correcting ability of the deformed sheets while the large sheet plunge angle is set.

Further, when the stack amount increases, it is possible to perform stable sheet ejection while suppressing a high-angle entry of the previously ejected sheet with a smaller sheet entry angle set.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a plan view showing the overall construction of the paper ejection device of the present invention, and a side view thereof is shown in FIG. According to the apparatus configuration shown in FIGS. 1 and 3, first, bearings (rolling bearings) 101 and 201 are fitted respectively at both ends of the rotation shafts 100 and 200 of the discharge roller 1 and the pinch roller 2 so as to be rotatable. With these bearings
By providing tension springs 5 and 6 between 101 and 201, the pinch roller 2 is pressed against the paper discharge roller 1 at a predetermined pressure. Further, a tension spring 9 similar to the above is provided between one end of the bearing 201 and a stud (support) 8 fixed to the frame 7 to apply a biasing force to the pinch roller 2 in the direction of arrow a and The wire 10 connected to the other end of the bearing 201 and having a certain length is guided by the guide roller 11 so as to oppose the force, and is extended from the paper discharge tray 3 and the upward movement is restricted by the stopper 12. It is connected to the support bar 13 that is provided. Further, a compression spring 14 for urging the paper discharge tray 3 in the direction of arrow b is provided between the paper discharge tray 3 and the apparatus main body,
In the state where the discharged sheets are not stacked as shown in the figure, the sheet discharge tray 3 is pushed upward until the support bar 13 contacts the stopper 12. The compression spring 14 is configured to contract as the stack amount of the sheets discharged onto the sheet discharge tray 3 increases, and is provided to displace the height of the sheet discharge tray 3 according to the weight of the sheet stack. It is the mechanism that was created.

Next, the operation of the device of the present invention will be described in detail. First, when the sheets 4 are not stacked on the sheet discharge tray 3 or when the stack amount is extremely small, the sheet discharge tray 3 is regulated by the compression spring 14 by the stopper 12 as shown in FIG. Maintained at the highest position. At this time, the length of the wire 10 extending from the discharge tray 3 between the guide roller 11 and the pinch roller 2 becomes the longest, and therefore the pinch roller 2 urged by the tension spring 9 is used.
Is held at a position closest to the stud 8 on the peripheral surface of the paper discharge roller 1. At this time, the piercing angle α ₁ of the sheet 4 discharged in the tangential direction at the contact point between the pinch roller 2 and the sheet discharge roller 1 into the sheet discharge tray 3 becomes relatively large and in the initial discharge state (when the stack is in a small amount). The sheet 4 can be stabilized (stationary) in a short time, and can be deformed into a curl shape to surely correct the posture of the sheet 4.

After that, when the stack amount of the sheets 4 discharged onto the sheet discharge tray 3 increases, the sheet discharge tray 3 gradually moves downward against the biasing force of the compression spring 14 according to the weight thereof. The displacement of the paper discharge tray 3 is transmitted to the pinch roller 2 through the wire 10 and the pinch roller 2
Is gradually moved to the left against the biasing force of the tension spring 9. As described above, since the pinch roller 2 is pressed against the paper discharge roller 1 by the tension springs 5 and 6, the paper discharge roller 1 is operated as an operation corresponding to the leftward movement.
A circular arc motion will be performed on the peripheral surface of while maintaining its pressure contact. The contact position of both rollers is gradually moved to the left along with this arc movement, whereby the discharge direction of the paper 4 discharged in the tangential direction at this contact gradually becomes upward as described above.

Then, as shown in FIG. 5, when a considerable amount of the sheets 4 are stacked on the discharge tray 3, this tendency further progresses, and accordingly, the sheet plunge angle α ₂ defined as described above is shown in FIG. The value is smaller than when the stack is small. That is, since the plunge angle of the sheet 4 into the already stacked sheets becomes small, the sheet 4 at the time of stack increase, which has been conventionally a problem due to the plunge angle into the stacked sheet,
It is possible to minimize the buckling or the rolling of the sheet 4 deformed into a curl (rolling of the sheet) to a minimum. The device of the present invention is suitable for a relatively large-capacity discharging device because the discharging angle can be changed according to the stack weight of sheets.

〔The invention's effect〕

As described above, according to the sheet discharging apparatus of the present invention, the stack amount of discharged sheets increases, and the sheet discharging angle with respect to the sheet discharging tray becomes gradually smaller as the sheet discharging tray moves downward. Therefore, it is possible to realize a stable stack of sheets that is always stable regardless of the stack amount without using an expensive and complicated structure and electrical means that requires control.

[Brief description of drawings]

1 and 3 are views showing the overall structure of the sheet discharging device of the present invention. FIG. 1 is a plan view, FIG. 3 is a side view, and FIG.
FIG. 4 is a diagram showing a configuration example of a conventional sheet discharging device, and FIGS. 4 and 5 are diagrams showing operation states in the apparatus of the present invention according to respective sheet stack amounts. 1 ... Paper discharging roller, 2 ... Pinch roller, 3 ... Paper discharging tray, 5,6,9 ... Tension spring, 7 ... Frame, 8 ... Stud, 10 ... Wire, 11 ... Guide roller , 12
...... Stopper, 13 ...... Support rod, 14 ...... Compression spring, 10
0,200 …… Rotary shaft, 101,201 …… Bearing (rolling bearing), α, α ₁ , α ₂ …… Paper entry angle

Claims (1)

[Claims] 1. A paper ejecting means for ejecting a paper in a tangential direction of the pressure contact, which comprises a support mechanism for press-contacting and supporting the pressure contact of the pinch roller with respect to the paper ejection roller so as to be movable. The sheet ejection tray has a height that is displaced according to the stack weight of the sheets, and a transmission unit that transmits the height displacement of the sheet ejection tray to the support mechanism. A paper ejection device, wherein the pressure contact of the roller pair is changed so that the ejection angle of the paper with respect to the paper ejection tray becomes gradually smaller in accordance with the height change of the paper tray.