JPS63225044A - Automatic paper feeder - Google Patents

Abstract

PURPOSE:To prevent sheets of paper from being jammed by mounting a feed-in guide plate retractably from a paper feed passage, loading the feed-in guide plate toward the paper feed passage with an elastic member and restricting the position of the plate in the direction of the paper feed passage with a stopper member. CONSTITUTION:When many sheets of paper are sent by a primary feed roller 10, a high pressing force is applied to a feed-in guide plate 30. Then the feed-in guide plate 30 is swung down against the load of a compressed coiled spring 32 to retract from the paper feed passage, whereby preventing many sheets of paper from being jammed between the secondary feed roller 15 and the feed-in guide plate 30. On the other hand a low limit stopper 34 restricts the retraction position of the feed-in guide plate 30, whereby preventing said guide plate 30 from coming into contact with the separation roller 20.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an automatic paper feeder that feeds paper sheets one by one in an image forming apparatus such as an electrophotographic copying machine.

Raiimo technique and its season.

Conventionally, in the automatic paper feed device of a copying machine, in addition to the paper feed roller that feeds paper by rotating and pressing against the top surface of the paper on the paper loading table, another paper feed roller is installed downstream of the paper feed roller. (Hereinafter, this paper feed roller will be referred to as the second paper feed roller, and the paper feed roller that presses against the top surface of the paper will be referred to as the first paper feed roller.); and a reversible separation roller that presses against the second paper feed roller. It has a judging mechanism consisting of. and,
This sorting mechanism is provided with a plunge guide plate that guides the paper fed from the first paper feed roller to the nip portion between the second paper feed roller and the separation roller.

However, with this model, the entry guide plate is fixed to the main body of the copying machine, so when the first paper feed roller finishes feeding out a large number of sheets, the leading edges of these papers enter the second paper feed roller. This has the problem that paper jams occur when the paper gets wedged between the paper and the guide plate. In particular, as the rollers are made smaller in diameter in order to downsize the device, such problems become more prominent.

In order to solve the above problems, the automatic paper feeder according to the present invention includes a plunge guide plate that guides the paper to the nip between the second paper feed roller and the separation roller in the paper feed path. It is characterized in that it is provided so as to be movable forward and backward relative to the paper feed path, is urged toward the paper feed path by an elastic member, and is positioned in the direction of the paper feed path by a stopper member.

In other words, the paper is fed from the top layer based on the rotation of the first paper feed roller that presses against the top surface of the paper, and is guided by the entry guide plate until it passes through the nip between the second paper feed roller and the separation roller. The paper enters the section, and all but the top layer of paper are returned by the reversal of the separation roller, and only the top layer of paper is fed downstream.The entry guide plate is fed by an elastic member. It is positioned by the stopper member while being biased toward the passage. Therefore, when a large number of sheets of paper are sent out, the entry guide plate resists the urging force and retreats from the paper feed path, preventing the leading edge of the paper from being wedged between the second paper feed roller and the entry guide plate. To prevent.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of an automatic paper feeder according to the present invention will be described with reference to the accompanying drawings.

[First embodiment, see Figure 1] In Figure 1, the automatic paper feed cassette (1) is a well-known type that can be attached to and detached from the paper feed slot of the main body of the copying machine. ) is rotatable about the hinge metal fitting (3) as a fulcrum, and is pushed upward by the push-up plate (4). The push-up plate (4) is rotatable about the support shaft (5), and is driven in the direction of arrow (a) by a motor (not shown). The height of the mounting table (2) is automatically adjusted by controlling the motor on and off so that the height of the uppermost surface of the paper sheet placed on its upper surface is always constant.

The second paper feed roller (15) is rotatably installed at the position shown in the figure with the support shaft (16> as a fulcrum).The first paper feed roller (10> is swingably supported on the support shaft (16). It is attached to the tip of the paper feed roller frame (11) and placed on the loading table (2).
It can be pressed against the top surface of the paper above.

The separation roller (20) is attached to a separation roller frame (22) that is swingably supported around a support shaft (21), and is attached to a second paper feed roller (15) by the biasing force of a compression coil spring (23). It is elastically pressed against.

Each of the rollers (10), (15), and (20) described above can be rotated counterclockwise by a drive system (not shown), and this rotation is controlled on and off at predetermined timing.

The entry guide plate (30) is installed to be able to swing vertically about the support shaft (31), and is supported by a compression coil spring (3
It is constantly urged upward by the urging force of 2).

The vertical swing position of this entry guide plate (30) is regulated by an upper limit stopper (33) and a lower limit stopper (34), the upper limit stopper (33) is fixed to the back surface of the separation roller frame (22), and the lower limit stopper ( 34) is fixed to the distal end surface of the cassette (1) via a bracket (35).

That is, the entry guide plate (30) is in a state in which its leading end has entered the paper feed path leading from the first paper feed roller (10) to the nip between the second paper feed roller (15) and the separation roller (20>). The position is regulated by an upper limit stopper (33).

Next, the operation of the automatic paper feeder having the above configuration will be explained.

The first paper feed roller (10) is pressed by its own weight to the top surface of the paper stacked on the #C table (2). This pressing force (sheet feeding pressure) is approximately 100 to 250 g, and is adjusted by providing an auxiliary spring (not shown) if necessary.

When the paper feed signal is turned on, each roller (10), (15)
.

(20) are rotated in the counterclockwise direction, and the paper is fed from the top layer based on the rotation of the first paper feed roller (10), and is guided by the entry guide plate (30) to the second paper feed roller (10). It enters the nip between the paper roller (15) and the separation roller (2o). At this time, two or three sheets of paper are fed out at the same time due to the frictional force between the sheets, and only the topmost sheet is fed to the right in the figure by the rotation of the second paper feed roller (15), and the other sheets are fed to the right in the figure. The paper is transferred to the cassette (by rotation of the separation roller (2o)
1) Returned to the side. The fed sheet of paper is conveyed to the transfer section via a conveyance roller (not shown).

In this way, the second paper feed roller (15) and the separation roller (20
) is able to separate sheets one by one by the frictional force between the second paper feed roller (15) and the paper, μm, the frictional force between the separation roller rough 20) and the paper, and the distance between the sheets. This is because the relationship is set as μm〉μ2〉μ3, where the frictional force is μ3.

During the above paper handling, the first liner roller (10)
When a large number of sheets of paper have been fed out, a large pressure force is applied to the plunge guide plate (30), causing the plunge guide plate (30) to be fed out.
30) swings downward against the biasing force of the compression fill spring (32) and retreats from the paper feed path. This prevents the leading edges of a large number of sheets from getting wedged between the second paper feed roller (15) and the leading edge of the entry guide plate (30) and causing a paper jam.

On the other hand, a predetermined separation pressure is maintained from the compression coil spring (23) to the separation roller (20). The retracted position of the entry guide plate (30) is regulated by the lower limit stopper (34);
This is to prevent the roller (2o) from falling too much by itself and coming into contact with the separation roller (2o).

By the way, in this embodiment, the separation roller (20) is also compressed by the compression coil spring (20) due to the rush of many sheets of paper.
It retreats downward against the biasing force of 3) to prevent defective handling operations. Furthermore, by providing the upper limit stopper (33) of the entry guide plate (30) on the separation roller frame (22), the tip of the entry guide plate <30) can be accurately installed at a position closer to the separation roller (20). Can be done. Moreover, the entry guide plate (30) not only retracts independently, but also moves in conjunction with the retraction of the separation roller (20), so that a constant positional relationship with the separation roller (20) can be maintained.

[Second Embodiment, see Figure 2] In Figure 2, the entry guide plate (30) is
) formed in the pin (30b), (30b).
6) and (36) so as to be movable up and down, and is constantly urged upward by a compression coil spring (32). The upper and lower limits are the lower and upper edges of the recess (30c) formed in the side piece (30a).
2) is regulated by coming into contact with the end stopper (22a).

Note that the other configurations are the same as those of the first embodiment, and the operations and effects are also the same.

[See Third Embodiment, Figure 3] In Figure 3, the entry guide plate (30) has side pieces (30d
) through the pin (37) to the separation roller frame (22)
It is swingably attached to and is constantly urged upward by a tension coil spring (38). The upper and lower limits are regulated by the ends (30e) coming into contact with stoppers (40>, (41) fixed to the separation roller frame (22)).

Note that the other configurations are the same as those of the first and second embodiments. The action and effect are the same, but in addition, by pivotally supporting the plunge guide plate (30) on the separation roller frame (22), the urging force by the tension coil spring (38) acts on the separation roller (20). There's nothing to do,
The separation pressure of the separation roller (20) against the second paper feed roller (15) can be adjusted only by the biasing force of the compression fill spring (23).

[Other Embodiments] The automatic paper feeder according to the present invention is not limited to the above embodiments, and can be modified in various ways within the scope of the gist.

In particular, the separation roller (20) is not necessarily retractable from the paper feed path, but may be fixed in position.

Furthermore, if the separation roller (20) and the tip of the entry guide plate (30) are configured in a comb-like shape so that they overlap each other,
There is no possibility that the two will come into contact when the entry guide plate (30) is retracted downward. Therefore, in this case, the lower limit stoppers (34) and (41>) are unnecessary.

As is clear from the above explanation, according to the present invention, the plunge guide plate is provided so as to be movable forward and backward with respect to the paper feed path, is urged toward the paper feed path by an elastic member, and Since the position in the direction of the paper feed path is regulated by a stopper member, when a large number of sheets of paper are sent out by the first paper feed roller, the entry guide plate automatically retreats from the paper feed path, and the leading edge of the paper is The paper does not get jammed between the two paper feed rollers and the entry guide plate, and reliable paper cutting performance is achieved.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway front view of the first embodiment, Fig. 2 is a partially cutaway front view of the second embodiment, and Fig. 3 is a partially cutaway front view of the second embodiment.
FIG. 2 is a partially cutaway front view of the embodiment. (1)...Cassette, (10)...First paper feed roller, (11)...Paper feed roller frame, (15)...
Second paper feed roller, (20)... Separation roller, (22a
)... End stopper, (30)... Entry guide plate,
(30c)... recess, (32)... compression coil spring, (33)... upper limit stopper, (38)...
Tension coil spring, (40>... upper limit stopper.

Claims (1)

[Scope of Claims] 1. A first paper feed roller that feeds paper by rotating while in pressure contact with the uppermost surface of the paper on a paper loading table, and a position downstream of the first paper feed roller in the paper feeding direction. In an automatic paper feeding device, the automatic paper feeding device includes a second paper feeding roller that is rotationally driven in the paper feeding direction, and a separation roller that is in pressure contact with the second paper feeding roller and is rotationally driven in the opposite direction to the paper feeding direction. A plunge guide plate is provided to guide the paper fed from the first paper feed roller to the nip portion between the second paper feed roller and the separation roller, and is movable forward and backward with respect to the paper feed path, and an elastic member is used to guide the paper into the nip portion between the second paper feed roller and the separation roller. An automatic paper feeder characterized in that it is biased towards the paper path and its position is regulated by a stopper member in the direction of the paper feed path.