JP3477703B2 - Paper feeder - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stack of papers (plain paper, coated paper, OHP (overhead projector) sheet, glossy paper, cut sheet such as glossy film), one from the top. The present invention relates to a sheet feeding device that feeds each sheet. The present invention mainly relates to a sheet feeding device suitable for a printer or the like.

[0002]

2. Description of the Related Art Generally, as a sheet feeding device, a claw separation system and a pad separation system are known.

In the claw separation method, as is well known, the tip corners of the stacked sheets are locked to the claws, and the paper feed roller is arranged behind the claws (downstream in the paper feeding direction). , By rotating the paper feed roller, the uppermost paper is bent between the paper feed roller and the claw portion, and the uppermost paper is moved to the next position by utilizing the fact that this bending reaches the limit. This is a method in which only the topmost sheet is fed by separating it from the other sheets.

On the other hand, in the pad separation method, as is well known, the friction coefficient between the paper feed roller and the paper is μ1,
When the friction coefficient between the separation pad and the paper is μ2 and the friction coefficient between the papers is μ3, the paper feed roller and the separation pad are configured and rotated so that the relationship of μ1>μ2> μ3 is established. This is a method in which the uppermost sheet and the next sheet are separated by pinching the sheet between the sheet feeding roller and the separation pad that is pressed against the sheet, and only the uppermost sheet is fed.

In any of these methods, when the surface of the uppermost sheet comes into contact with the rotating sheet feeding roller and the uppermost sheet moves, the back surface of the uppermost sheet is on the other side of the contact portion. And the surface of the next paper will come into sliding contact with each other, and therefore, the surface of the next paper will have a thin scratch due to the sliding contact, and if the paper is glossy paper or a glossy film, the thin scratch will be slightly noticeable. .

Further, in the case of the claw separation system, the sliding contact portion (that is, the thin scratched portion) is located behind the claw portion, that is, the rear side of the uppermost sheet so that the uppermost sheet can be flexed. It is located in the area, which is not preferable.

On the other hand, in the case of the pad separation method, although a thin scratch is caused by sliding contact, this thin scratch only attaches to the front end of the surface of the next paper, and therefore is not normally located in the print area. .

Therefore, from the viewpoint of the above-mentioned thin scratches,
The pad separation method is superior.

However, the pad separation method has the following drawbacks.

For example, as shown in FIG. 26, when the paper feed device 1 using the pad separation method is used in a printer, the fed paper P1 is conveyed while being pinched by the conveyance rollers 2 and 3. Although the printing is performed by the printing unit 4, the paper P1 is not normally completely removed from the paper feeding device when the transportation of the paper P1 by the transportation rollers 2 and 3 is started.

On the other hand, in the pad separation system, the above μ1
>Μ2> μ3, that is, when the frictional force between the paper feed roller and the paper is f1, the frictional force between the paper and the separation pad is f2, and the frictional force between the paper and the paper is f3, f
Since the paper feed roller and the separation pad must be pressed against each other so that the relationship of 1>f2> f3 is established, the paper feed roller and the separation pad are separated from each other when the conveyance of the paper P1 by the conveyance rollers 2 and 3 is started. Is pressed, the paper P1
Is in a state where the rear part thereof is pinched by the paper feed roller and the separation pad.

Therefore, the sheet P1 is conveyed under a load (pulled rearward) under the load of the pressure-holding portion until the trailing edge of the paper P1 passes through the pressure-holding portion between the paper feed roller and the separation pad. It will be conveyed by the rollers 2 and 3.

If such a load (that is, back tension) is large, the feeding accuracy of the paper by the conveying rollers 2 and 3 is deteriorated, and the printing quality is also deteriorated. It is desirable that the pressure contact force of is as small as possible. However, if the pressure contact force is small, there is a drawback that the next paper sheet gradually enters the pressure contact portion between the paper feed roller and the separation pad every time the paper feed operation is repeated, and the paper sheets cannot be separated.

A sheet medium aligning mechanism described in Japanese Patent Laid-Open No. 7-53062 is a solution to these problems.

FIGS. 27A to 27E are views showing the structure and operation of this mechanism.

In the figure, 18 is a paper feed roller, 24 is a separation pad, and 22 is a lever.

The lever 22 is rotatably supported by a pivot A as shown in FIG. 3C, and is urged clockwise by a cantilever spring 26 that presses the arm 22c.

According to this mechanism, when the paper feed roller 18 rotates in the clockwise direction as shown in FIGS. 8B to 8E, the uppermost sheet S1 at the pressure contact portion between the paper feed roller 18 and the separation pad 24. Is separated from the next highest sheet S2, and only the highest sheet S1 is fed as shown in FIG. On this occasion,
The lever 22 is pushed by the sheet S1 and escapes as shown in FIGS. Then, even if the next sheet S2 (and further the next sheet S3) enters or is about to enter the pressure contact portion between the paper feed roller 18 and the separation pad 24, the trailing end of the previous sheet S1 is the lever 22. When the lever 22 passes the upper end, the lever 22 is rotated clockwise by the urging force of the cantilever spring 26, and the next sheet S2 (and further the next sheet S3) is pushed back as shown in FIG. Becomes

Therefore, according to this mechanism, the above-mentioned problem, that is, the next sheet of paper gradually enters the pressure contact portion between the paper feed roller and the separation pad and the paper cannot be separated, is once solved. It

However, the paper feed roller 1 as described above
8, that is, a paper feed roller having a circular shape when viewed from the side, is in a state of being constantly pressed against the separation pad, and thus has a drawback that it is easily worn.

Therefore, in order to solve this difficulty, there is known a sheet feeding device in which the sheet feeding roller is D-shaped in a side view.

As an example thereof, FIG.
The sheet feeder described in Japanese Patent No. 396 is shown.

In the figure, reference numeral 40 denotes a paper feed roller having a substantially D-shape in side view, which has an arc portion 40a and a straight portion 40b.

Reference numeral 41 is a guide block, and the shaft 40c of the paper feed roller 40 is supported by the guide block 41.

Reference numeral 42 is a cassette, and a loading plate 42 is provided inside.
a is provided. A plurality of sheets of paper P are set in a stacked state on the stacking plate 42a. 42c is a spring, and the paper P is biased toward the paper feed roller 40 by the spring 42c.

Reference numeral 43 is a separation pad, which is a bracket 43.
It is mounted on a. The separation pad 43 is located in the rotation path of the arc portion 40a of the paper feed roller 40,
The spring 44 biases the guide roller 45 in the direction of the paper feed roller shaft 40c.

Reference numeral 46 is an idle roller rotatably attached to the guide block 41, and 47 is the guide block 4.
A shaft 47a is movably attached to the first long groove 41a. Movable idle roller 47
Is urged toward the separation pad 43 by the spring 48 and is in contact with the separation pad 43.

The biasing force F2 of the spring 48 is set smaller than the biasing force F1 of the spring 44 of the separation pad 43 (that is, F1> F2).

The paper feeding apparatus as described above operates as follows.

In the standby state, as shown in FIG. 28, the linear portion 40b of the paper feed roller 40 faces the paper P, and the paper feed roller 40 is not in contact with the paper P.
The biasing force F2 of the spring 48 of the movable idle roller 47 is the biasing force F of the spring 44 of the separation pad 43.
Since it is set to be smaller than 1, the movable idle roller 47 is pushed up by the separation pad 43, and its shaft 47a is in contact with the upper end of the long groove 41a.

During the paper feed operation, the paper feed roller 40 rotates in the direction of the arrow, and the arc portion 40a thereof contacts the uppermost paper P1 of the paper P, so that the paper P1 is directed toward the separation pad 43. Sent. At this time, the paper P2, which is next to the paper P1, is adsorbed by the action of static electricity, or the frictional force acts between the paper P1 and the paper P2. May be

However, the sheet P2 is separated from the sheet P1 by the separation pad 43 in the following manner, and only the uppermost sheet P1 is fed.

That is, when the leading edge of the sheet P2 hits the separation pad 43, its movement is hindered and the sheet P2 can be temporarily separated from the sheet P1.

Further, the frictional force between the arc portion 40a of the paper feed roller 40 and the paper P1 is f1, and the paper P2 and the separation pad 4 are.
When the frictional force between the sheet P3 and the sheet P3 is f2 and the frictional force between the sheets P1 and P2 is f3, the paper feed roller 40 and the separation pad 43 are configured so that the relationship of f1>f2> f3 is established. Therefore, when the paper P1 and the paper P2 are both pressed by the arc portion 40a of the paper feed roller and the separation pad 43 as the paper feed roller 40 rotates, the paper P2
The friction between the separation pad 43 and the separation pad 43 hinders the movement of the separation pad 43, so that it is secondarily separated from the sheet P1 and only the sheet P1 is fed. The separation pad 43 is
Since the arcuate portion 40a of the sheet feeding roller 40 is located in the rotation path of the arcuate portion 40a, the arcuate portion 4a is rotated to rotate the arcuate portion 4a.
However, since the movable idle roller 47 is biased toward the separation pad 43 by the spring 48, even if the separation pad 43 is pressed down, the movable idle roller 47 comes into contact with the separation pad 43, and this contact also causes the paper to move. The separation operation will be performed.

The paper feed roller 40 makes one full rotation and returns to the standby state (the state shown in FIG. 28).

As described above, only the uppermost sheet P1 is fed.

According to such a sheet feeding device, since the sheet feeding roller 40 is not always in pressure contact with the separation pad 43, wear is reduced.

Further, since the movable idle roller 47 is pressed against the separation pad 43 by the spring 48, it is possible to prevent the next sheet from advancing into the pressure contact portion along with the uppermost sheet to some extent.

[0039]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
Sheet medium alignment mechanism described in Japanese Patent No. 3062 (FIG. 27)
After the uppermost sheet S1 is fed as shown in FIG. 27 (d), the lever 22 is rotated as shown in FIG. 27 (e) to move the next sheet S2 (and the next sheet S3). ) Is pushed back, so that when the next-order sheet S2 moves together with the highest-order sheet S1 and its leading edge passes through the tip of the lever 22, the next-order sheet S2 can no longer be pushed back. It's gone.

In such a situation, that is, the uppermost sheet S
When feeding 1, or even the topmost sheet S thereafter
The fact that the leading edge of the next sheet S2 passes the leading edge of the lever 22 when 1 is transported by a downstream transport roller or the like increases the pressure contact force between the sheet feeding roller 18 and the separation pad 24. It is possible to prevent this.

However, if the pressure contact force between the paper feed roller 18 and the separation pad 24 is increased, the above-mentioned load (back tension) at the time of paper conveyance becomes extremely large.
In order to obtain a conveyance force sufficient to overcome this load, it is necessary to increase the sandwiching force of the sheet by the conveyance rollers (2 and 3 in FIG. 26) and at the same time, a large driving force for driving the conveyance roller and the like. Are required, which causes a problem that the device becomes large and power consumption increases. Also,
There is also a problem that the transport rollers and the like are easily worn.

Such a problem is, for example, in the structure described in Japanese Utility Model Publication No. 8-3396 shown in FIG.
7 described in JP-A-7-53062
The same occurs when 2 is provided. That is, in this case, unless the pressure contact force between the movable idle roller 47 and the separation pad 43 is increased, when the fed uppermost sheet is further conveyed by a conveying roller or the like in the subsequent stage, the next sheet is conveyed. It is not possible to prevent the situation in which the tip of the blade passes the tip of the lever 22, and then the back tension becomes large.

An object of the present invention is to solve the above problems, and in a sheet feeding device using a separation pad system and a sheet return lever, the leading edge of the next sheet can be moved without increasing the back tension. This is to make it difficult to pass the tip of the paper return lever.

[0044]

[0045]

[0046]

[Means for Solving the Problems] To achieve the above object
According to another aspect of the present invention, there is provided a paper feeding device having a circular arc portion and a straight line portion, the paper feeding roller having a substantially D shape in a side view, which rotates in a forward direction during a paper feeding operation, and the circular arc portion of the paper feeding roller. Paper to be fed by stacking a plurality of sheets, and the paper is pressed between the hopper that presses the paper toward the paper feed roller when the paper feed roller rotates forward and at least the arc portion when the paper feed roller rotates normally. The separation pad for separating the paper to be fed by the paper feed roller from the next paper, and at least when the separation pad does not press the paper between the arc portion of the paper feed roller. And the trailing edge of the uppermost sheet fed by the paper feed roller passes after passing the idle roller that regulates the movement of the next sheet of paper and then rotates backward to move the next sheet of paper. The tip is from the contact portion between the idle roller and the separation pad. A paper return lever that pushes back the next paper toward the rear so that it is located rearward, a position of the paper return lever when the uppermost paper is fed by the paper feed roller, the separation pad, and the idle roller. A sheet path is formed between the sheet and the abutment position of the separating pad, and when the leading end portion of the sheet passing through this passage is curved toward the paper feed roller, the leading end portion is formed. And a guide that abuts against.

According to a second aspect of the present invention, in the paper feeding device according to the first aspect, a surface of the separation pad facing the paper feed roller and a surface of the guide facing the separation pad are substantially parallel to each other. Alternatively, the distance between the both facing surfaces is formed to be narrower toward the downstream side in the sheet feeding direction.

According to a third aspect of the present invention, there is provided the paper feeding device according to the first aspect.
In the paper feeding device according to the second aspect, the surface of the separation pad facing the paper feed roller is located downstream of the contact portion between the separation pad and the idle roller with respect to the paper feed roller. It is characterized by being curved in a concave shape.

According to a fourth aspect of the present invention, there is provided the paper feeding device according to the first or second aspect.
In the paper feeding device described in 2 or 3 , the guide is
It is characterized in that it is provided integrally with an idle roller holder that supports the idle roller.

A paper feeding device according to a fifth aspect is the paper feeding device according to any one of the first to third aspects.
In the paper feeding device described in any one of 4, the paper to be fed by the paper feeding roller is stacked in an inclined state.

The paper feeding device according to claim 6 is the paper feeding device according to claim 1 .
5. In the paper feeding device according to any one of 5 , the contact force between the separation pad and the idle roller is set to be smaller than the contact pressure between the paper feeding roller and the separation pad. Characterize.

A sheet feeding device according to a seventh aspect is a sheet feeding device according to the first aspect.
5. The paper feeding device according to any one of 5 , wherein a separation mechanism that separates the separation pad from the idle roller when the paper return lever pivots backward and pushes back the next paper toward the rear. It is characterized by having.

The sheet feeding device according to claim 8 is the sheet feeding device according to claim 1 .
7. In the paper feeding device according to any one of 7, the hopper is configured such that when the paper return lever rotates rearward,
The hopper separates the sheets stacked in the hopper from the sheet feeding roller, and a supporting surface for supporting the leading end of the sheets stacked in the hopper is provided in front of the hopper in the sheet feeding direction. The sheet return lever pushes back the next-order sheet so that the leading edge of the next-order sheet reaches behind the support surface.

A paper feeding device according to a ninth aspect is a paper feeding device according to any one of the first to third aspects.
8. The sheet feeding device according to any one of 8 , further comprising a biasing member that biases the sheets stacked on the hopper toward a sheet supporting surface of the hopper. .

According to a tenth aspect of the present invention, there is provided the paper feeding device according to the first aspect.
In the paper feeding device according to any one of Claims 9 to 9, the paper feeding roller is a roller that normally rotates once during a paper feeding operation, and reverses once before the first rotation, and the paper is fed by the reverse rotation. It is characterized in that the return lever rotates rearward.

[0056] paper feeding apparatus according to claim 11, wherein the claim 1
9. The sheet feeding device according to any one of claims 9 to 9 , wherein the idle roller is separated from the separation pad when the leading end of the sheet to be fed passes between the separation pad and the idle roller, After the tip of the sheet passes between the separation pad and the idle roller, the idle roller is brought into contact with the separation pad before the contact between the arc portion of the paper feed roller and the separation pad is released. It is characterized by having a roller retracting mechanism.

The paper feeding device according to claim 12 is the paper feeding device according to claim 1.
In the paper feeding apparatus described in 1 , the idle roller retracting mechanism is provided on a shaft of the paper feeding roller and is operated by a cam that rotates together with the shaft.

[0058]

[0059]

[0060]

[0061]

[0062]

[0063]

[0064]

[0065]

[Advantageous effects] According to the sheet feeding apparatus according to claim 1, and a circular arc portion and a straight portion, the paper feed roller side view D-shaped in a normal direction during the feeding operation, said paper feed roller A hopper that stacks a plurality of sheets of paper to be fed in contact with the arc portion and presses the paper toward the paper feeding roller when the paper feeding roller rotates normally, and at least the arc portion when the paper feeding roller rotates normally. It is equipped with a separation pad that separates the paper to be fed by the paper feed roller from the next paper by pinching the paper between the paper and the paper, so that only the top paper is fed during the paper feeding operation. To be done.

When the fed uppermost sheet is conveyed by a conveying roller or the like in the subsequent stage, the next sheet is attracted to the uppermost sheet by the action of static electricity, or Due to the frictional force acting on the next paper, the next paper may try to be fed together with the top paper, but the movement of this next paper is restricted by the idle rollers, and After the trailing edge of the trailing edge has passed, the paper return lever is rotated rearward so that the leading edge of the next sheet is pushed back so that its leading edge is positioned behind the contact portion between the idle roller and the separation pad. Be done.

If the leading edge of the next paper sheet passes through the leading edge of the paper return lever when the paper return lever is rotated rearward, the next paper sheet will not be pushed back by the paper return lever. Such a situation is likely to occur when the leading end portion of the next paper is curved in the direction away from the separation pad, that is, the paper feed roller side. If the leading edge of the next sheet is curved toward the paper feed roller, the leading edge of the sheet that has passed the contact position between the separation pad and the idle roller does not contact the separation pad, or even if it contacts. This is because the contact force becomes small, and therefore, the resistance due to the separation pad is not received or the resistance becomes small.

[0068] In contrast, according to the paper feeding device of the first aspect, the contact between the position of the return sheet when the uppermost sheet is fed by the feed roller lever and the separation pad and the idle roller A guide for forming a paper path between the position and the separation pad and for contacting the leading end of the paper passing through the passage when the leading end is curved toward the paper feed roller. Is equipped with
If the leading end portion of the next sheet that has passed the contact position between the separation pad and the idle roller is curved toward the paper feed roller, the leading end portion contacts the guide,
The elastic force of the leading end portion (curved portion) of the sheet itself causes the sheet to be pressed against the separation pad, and as a result, the resistance of the separation pad is received.

Therefore, even if the pressure contact force between the separation pad and the idle roller is not so large, it is unlikely that the next-order sheet whose front end portion is curved toward the sheet-feed roller moves together with the highest-order sheet. As a result, it becomes difficult for the leading edge of the next sheet to pass through the leading edge of the sheet return lever when the sheet return lever rotates rearward.

[0070] That is, according to the paper feeding device of the claim 1, wherein, without increasing the back tension can be the tip of the next order of the sheet is difficult to pass the tip of the paper return lever, as a result, The stacked sheets can be reliably fed one by one without increasing the load (back tension) by using the separation pad method.

According to the sheet feeding device of the second aspect, in the sheet feeding device of the first aspect, a surface of the separation pad facing the sheet feeding roller and a surface of the guide facing the separation pad are substantially formed. Since the parallel or the space between the both facing surfaces is formed to be narrower toward the downstream side in the sheet feeding direction, the leading edge of the next sheet whose leading edge is curved toward the paper feed roller is more reliable. Then, it comes into contact with the guide and reliably receives the resistance of the separation pad.

Therefore, even if the pressure contact force between the separation pad and the idle roller is not increased so much, the next sheet whose front end portion is curved toward the sheet feeding roller is more likely to move together with the uppermost sheet. As a result, when the paper return lever rotates rearward, the situation in which the leading end of the next paper has passed the leading end of the paper return lever becomes even less likely to occur.

According to the paper feeding device of the third aspect, in the paper feeding device of the first or second aspect, the surface of the separation pad facing the paper feeding roller is in contact with the separation pad and the idle roller. Since it is curved concavely with respect to the sheet feeding roller on the downstream side of the sheet in the sheet feeding direction, the following operational effects are obtained.

That is, since the surface of the separation pad facing the paper feed roller is not curved on the upstream side in the feeding direction,
As a result, the space between the separation pad and the paper feed roller is secured on the upstream side, and it becomes easier for the paper to be introduced between the separation pad and the paper feed roller during the paper feeding operation, while the paper is idled by the idle roller on the downstream side. Since it is pressed to the separation pad side, if the leading edge of the next sheet that has passed the contact position between the separation pad and the idle roller is not curved toward the paper feeding roller, the leading edge of Even if the leading edge of the next sheet that passes through the contact position between the separation pad and the idle roller is curved toward the paper feed roller side, the tip of the separation pad more reliably abuts the curved surface of the separation pad. The portion comes into contact with the guide and is pressed against the separation pad by the elastic force of the leading end portion (curved portion) of the paper sheet, and receives the resistance of the separation pad.

Therefore, according to the sheet feeding device of the third aspect , a smoother feeding state can be obtained, and
It is even less likely that the leading edge of the next-order sheet will pass the leading edge of the sheet return lever.

According to the sheet feeding device of the fourth aspect, in the sheet feeding device of the first, second, or third aspect , the guide is provided integrally with an idle roller holder that supports the idle roller. Therefore, it is not necessary to separately provide a supporting member that supports the guide, and the structure can be simplified.

Moreover, the idle roller is a member that comes into contact with the separation pad, and as a result of the guide being provided integrally with the idle roller holder that supports this idle roller, the gap between the guide and the separation pad (ie, Since the paper path will be formed properly,
It is possible to more reliably obtain the effects of the sheet feeding device according to the first , second, or third aspect of the invention described above.

According to the sheet feeding device of the fifth aspect, in the sheet feeding device according to any one of the first to fourth aspects, the sheet to be fed by the sheet feeding roller is in an inclined state. Since they are stacked, the installation area is reduced.

Since the sheets are stacked in an inclined state on the hopper, when the uppermost sheet is fed, the next-highest sheet also easily descends toward the sheet feeding roller. When the arc portion and the separation pad are in pressure contact with each other, the pressure contact portion impedes the lowering of the next sheet.

Since the paper feed roller is substantially D-shaped in side view having an arc portion and a linear portion, the pressure contact between the arc portion and the separation pad is released during the rotation of the paper feeding roller, and the linear portion is separated from the separation pad. When the pressure contact portion disappears, the next sheet of paper tries to descend, but at this time, the idle roller comes into contact with the separation pad and regulates the descending of the next sheet of paper. The descent of the next paper is regulated.

After the trailing edge of the uppermost sheet fed by the sheet feeding roller has passed, the leading edge of the succeeding sheet is moved to the idle roller by the backward movement of the sheet return lever. The next-order sheet is pushed back toward the rear so that it is located behind the contact portion with the separation pad.

Moreover, as described above, when the paper return lever is rotated rearward, it is unlikely that the leading edge of the next paper has passed the leading edge of the paper return lever. The paper return operation by the return lever is surely performed.

Therefore, according to the paper feeding device of the fifth aspect , the paper feeding roller is a D-shaped roller, and the sheets are stacked in an inclined state to reduce the installation area. It is difficult for the next paper to gradually (cumulatively) enter the pressure contact portion between the paper feed roller and the separation pad, and the paper cannot be separated.

[0084] According to the sheet feeding apparatus according to claim 6, wherein, in the sheet feeding apparatus according to any one of claims 1 to 5, in comparison with the clamping pressure between the feed roller and the separation pad,
Since the contact force between the separation pad and the idle roller is set to be smaller, the addition (back tension) acting on the rear portion of the fed uppermost sheet is further reduced.

More specifically, in the conventional sheet feeding device shown in FIG. 28, as described above, the sheet feeding roller 40 makes one rotation during the sheet feeding operation, and the state shown in FIG.
Becomes a state in which the separation pad 43 is not pressed), the urging force F1 of the spring 44 of the separation pad 43 is set to be larger than the urging force F2 of the spring 48 of the movable idle roller 47. The movable idle roller 47 is stopped in a state of being pushed up until its shaft 47a comes into contact with the upper end of the long groove 41a.

That is, in the conventional paper feeding device, the paper P1
Is separated by the urging force F1 of the spring 44 of the separation pad 43 from the separation pad 43 and the movable idle roller 4
In the state of being clamped between the sheet and the sheet 7, the sheet is conveyed by the conveying rollers 2 and 3 shown in FIG. 26, for example.

The separation pad 43 prevents the paper from being fed when two or more papers are to be fed by pinching the paper with the arc portion 40a of the paper feed roller 40 as described above. Therefore, the urging force F1 needs to be set relatively large (at least larger than the urging force F2 of the movable idle roller 47 as described above).

In the conventional sheet feeding device, since the rear portion of the sheet P1 is clamped by the relatively large urging force F1, the load on the pinching portion is large.
Moreover, if the flexible idle roller 47 is used to prevent the above-described cumulative entry of the next sheet, the urging force F2 of the movable idle roller 47 must be increased.

On the other hand, according to the sheet feeding device of the sixth aspect, by adopting the configuration according to any one of the first to fifth aspects, the sheet feeding roller and the separation pad are sandwiched. Even though the contact force between the separation pad and the idle roller is set to be smaller than the pressure, the leading edge of the next sheet of paper when the paper return lever is rotated rearward is the tip of the paper return lever. Since it is unlikely that the paper will have passed through the paper, the paper return operation is reliably performed by the paper return lever, and as a result, the next paper is gradually (cumulatively) accumulated in the pressure contact portion between the paper feed roller and the separation pad. It will be difficult for the situation that the paper cannot be separated after it has entered.

Therefore, it is possible to further reduce the addition (back tension) acting on the rear portion of the fed uppermost sheet.

According to the paper feeding device of the seventh aspect, in the paper feeding device according to any one of the first to sixth aspects, the paper return lever is rotated rearward to move the next paper. Since the separating mechanism is provided to separate the separation pad from the idle roller when the sheet is pushed back to the rear, the next sheet can be smoothly pushed back.

According to the paper feeding device of the eighth aspect, in the paper feeding device of any one of the first to seventh aspects, the hopper is provided when the paper return lever is rotated rearward. , A hopper that separates the sheets stacked in the hopper from the paper feed roller, and
A support surface for supporting the leading edge of the sheets stacked on the hopper is provided in the front of the sheet feeding direction, and the sheet return lever is arranged so that the leading edge of the next sheet reaches the rear side of the supporting surface. Since it is configured to push back the first sheet of paper, the leading end of the next sheet of paper that has been pushed back is supported by the support surface.

Therefore, the above-mentioned cumulative entry of the next-higher sheet can be prevented more reliably.

According to the sheet feeding device of the ninth aspect, in the sheet feeding device according to any one of the first to eighth aspects, the sheets stacked on the hopper are placed on the sheet supporting surface of the hopper. Since the urging member for urging the urging member is provided, the next paper pushed back will be dropped onto the hopper by the urging member, and the leading edge of the next paper pushed back will surely come out. Will be supported on the support surface.

Therefore, the above-mentioned cumulative intrusion of the next sheet is more surely prevented.

According to the paper feeding device of the tenth aspect, in the paper feeding device according to any one of the first to ninth aspects, the paper feeding roller is a roller that rotates normally once during a paper feeding operation. In addition, since the paper return lever is rotated once before the one rotation and the paper return lever is rotated backward by this reverse rotation, the paper is fed by the paper feed roller for some reason before the paper feed operation is started. Even if it enters between the separation pad and the separation pad, it can be surely returned once.

Therefore, if a paper feed operation is performed as it is while the paper is inserted between the paper feed roller and the separation pad for some reason, a trouble (for example, a defective cue of the paper) may occur. Can be prevented.

According to an eleventh aspect of the present invention, in the sheet feeding device according to any one of the first to tenth aspects, the leading end of the sheet to be fed is a separation pad and an idle roller. The idle roller is separated from the separation pad when passing through the gap, and the leading edge of the paper passes between the separation pad and the idle roller, and then the arc portion of the paper feed roller and the separation pad are interposed. Since the idle roller retreating mechanism for bringing the idle roller into contact with the separation pad before the contact is released, the following operational effects are obtained.

That is, during the paper feeding operation, the paper feeding roller rotates to feed the uppermost paper, and when the leading edge of the paper tries to pass the contact portion between the arc portion of the paper feeding roller and the separation pad, When the idle roller is urged toward the separation pad and is in contact with the separation pad, the idle roller becomes a resistance against the sheet of paper passing through.

On the other hand, according to the paper feeding apparatus of the eleventh aspect , when the leading edge of the paper to be fed passes between the separation pad and the idle roller, the idle roller is separated from the separation pad. Since the mechanism is provided, the idle roller does not become a resistance to the sheet of paper that is about to pass.

The retracting mechanism is arranged so that, after the leading edge of the sheet has passed between the separation pad and the idle roller, before the contact between the arc portion of the sheet feed roller and the separation pad via the sheet is released. Since the idle roller is brought into contact with the separation pad, the contact between the arc portion of the paper feed roller and the separation pad via the paper is released, and then the next paper is sent together with the top paper. Nothing.

According to the paper feeding device of the twelfth aspect, in the paper feeding device of the eleventh aspect , the idle roller retracting mechanism is provided on a shaft of the paper feeding roller and is operated by a cam rotating together with the shaft. Since it is configured to be, it is possible to simplify the structure. For example, the structure can be simple as compared with the case where it is operated by a solenoid or the like.

[0103]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

The embodiment to be described here is based on the sheet feeding device of Japanese Patent Application No. 8-298043 filed by the applicant of the present application as a basic configuration and is improved. The paper feeding device will be described.

FIG. 1 is a perspective view showing a basic structure of an embodiment of a paper feeding device according to the present invention, and FIG. 2 is a view showing an example of attachment to a printer, a side view of a part of which is transparent. .

As shown in FIG. 1, the paper feeding device SF is
A frame 100, a paper feed roller shaft 110 rotatably supported by the frame, and a pair of paper feed roller units 120, 12 attached to the paper feed roller shaft 110.
0 ′ and a hopper 130 rotatably attached to the frame 100.

An edge guide 131 slidable in the width direction of the paper is attached to the hopper 130. One of the pair of paper feed roller units 120 and 120 ′ is connected to the edge guide 131, and is slidable along the paper feed roller shaft 110 together with the edge guide 131. There is.

Such a sheet feeding device SF is shown in FIG.
It is built into the printer as shown in. In FIG.
Reference numerals 2 and 3 are a pair of transport rollers for transporting the sheet, 4 is a print head for printing on the sheet, 5 and 6 are a pair of discharge rollers for discharging the printed sheet, and 8a and 8b are sheet guides.

The hopper 130 is inclined as shown in the drawing, and a plurality of sheets of paper P (FIG. 2) are set on the hopper 130 in a stacked state.

The edge guide 131 shown in FIG. 1 is slid to match the width of the sheet set by the user and guides one side edge of the sheet to be fed. The other side edge is
It is guided by the side wall 101 of the frame 100. Therefore, the other paper feed roller unit 120 is the paper feed roller shaft 1
Do not slide on 10.

A pair of paper feed roller units 120, 12
0'is symmetrically configured, and is different only in whether or not it slides. Therefore, with respect to the sheet feeding roller unit, only one sheet feeding roller unit 120 will be described below.

FIG. 3 is a partially cut side view mainly showing the sheet feeding roller unit of the sheet feeding device, and FIG.
IV sectional view, FIG. 5 is a sectional view mainly showing the paper feed roller and hopper, and FIG. 6 is a partially omitted plan view of FIG.

In these figures, reference numeral 121 denotes a paper feed roller, which is formed in a substantially D shape in a side view having an arcuate portion 121a and a straight portion 121b, and at least an arcuate portion 121.
The surface of a and the surface of the straight portion 121b are formed of a high friction material (for example, rubber). This paper feed roller 121
Is fixed to the paper feed roller shaft 110 mainly through a bush 122 as shown in FIG. That is, the paper feeding roller 121 and the bush 122 are the same as the paper feeding roller shaft 11.
It cannot rotate with respect to 0. The paper feed roller shaft 110 is rotatably driven by exactly one rotation during a paper feed operation by a driving unit (not shown) via a gear 111 (see FIG. 1) fixed to the shaft end thereof.

The hopper 130 has a shaft 13 as shown in FIG.
It is rotatably attached to the frame 100 by 2. Reference numeral 137 is a paper feed tray, which is attached to the printer. A plurality of sheets of paper P are set in a stacked state on the hopper 130 and the paper feed tray 137 (see FIG. 2). The leading edge Pa of the set paper P is supported and aligned by contacting the back surface (support surface) 152 of the separation pad holder 151 described later.

Reference numeral 140 denotes a frame of the paper feed roller unit 120 (hereinafter referred to as a subframe), and a hopper spring (compression spring) 133 is provided between the subframe 140 and the tip of the hopper 130. Therefore, the hopper 130 is always urged by the hopper spring 133 in the clockwise direction in FIG. 5, that is, in the direction in which the paper P is brought into contact with the paper feed roller 121. However, as shown in FIGS. Cam followers 134 are formed at both ends of the cam 130.
Is a hopper cam 135 fixed to the paper feed roller shaft 110.
(See FIG. 1) the rotation thereof is restricted. As shown in FIGS. 5 and 6, the hopper 1
A pad 136 similar to a separation pad described later is provided on the upper surface of the tip portion of 30.

A separation pad 150 is fixed to the separation pad holder 151. The separation pad 150 is made of a material (for example, a material such as cork) whose coefficient of friction with respect to the paper P is smaller than that of the paper feed roller 121. Further, each of the friction coefficients is made of a material having a friction coefficient larger than that between the sheets. That is, the friction coefficient between the paper feed roller 121 and the paper is μ
1, the friction coefficient between the separation pad 150 and the paper is μ2,
If the friction coefficient between sheets is μ3, then μ1>μ2> μ
It is 3.

As shown in FIGS. 7 and 8, the separation pad holder 151 includes a pad supporting portion 153 to which the separation pad 150 is fixed, and a support surface (rear surface) 152 portion of the above-mentioned sheet which is integral with the pad supporting portion 153. The sub-frame 140 has an arm portion 154 formed integrally therewith, and the shafts 155 provided on both sides of the rear end of the arm portion 154 fit into the track holes 140a of the sub-frame 140.
Is rotatably attached to.

A pad spring (compression spring) 156 as a pad urging means is provided between the lower surface of the pad support portion 153 and the sub-frame 140. Therefore, the separation pad holder 151 is always urged by the pad spring 156 in the clockwise direction in FIG. 5, that is, in the direction of bringing the separation pad 150 into contact with the sheet feeding roller 121. Is the protrusion 157
(See FIGS. 7 and 8) are formed, and the protrusion 157 is formed.
However, as shown in FIG. 4, its rotation is regulated by abutting on a pin 141 (see FIG. 8) which is a pad regulating means provided on the sub-frame 140. With the protrusion 157 in contact with the pin 141, the separation pad 150 is located on the rotation path of the arc portion 121 a of the paper feed roller 121.

In FIGS. 3 to 5 and 9, 160
Is an idle roller, and 161 is an idle roller holder. Incidentally, 170 is a cover of the paper feed roller 121,
It is attached to the subframe 140.

The idle roller holder 161 has a substantially ring shape having a hole 161a at its center. A shaft 163 is provided below one side surface of the idle roller holder 161, and the idle roller 160 is rotatably supported by the shaft 163. In FIG. 9, 163
a is a retaining hook.

As shown in FIG. 9, the idle roller holder 161 is formed with a pair of claws 161b and 161b. These claws 161b and 161b are formed on the sub-frame 14a.
The idle roller holder 161 is attached to the sub-frame 140 by lightly fitting with the long holes 142, 142 provided at 0. As shown in FIGS. 4 and 5, a pair of pins 161c and 161c are provided above and below the other side surface of the idle roller holder 161, respectively. As shown in FIGS. Track holes 143, 14 formed in the frame 140
It fits slidably with respect to 3. further,
As shown in FIG. 4, the paper feed roller shaft 110 and the bush 122 are inserted into the hole 161a of the idle roller holder 161, and the diameter of the hole 161a is formed larger than the outer diameter of the corresponding portion 122a of the bush 122. Has been done.

Therefore, the idle roller holder 161
The pins 161c, 161c have track holes 143,
By being guided by 143, the arrow a in FIG.
Slidable in the direction of 1, a2, and therefore also
The idle roller 160 can also slide in the directions of arrows a1 and a2.

As shown in FIGS. 3, 4, and 9, a spring receiving portion 164 is provided above the idle roller holder 161.
Is provided, and a roller spring (tensile coil spring) 165 as a roller urging unit is provided so as to straddle the spring receiving portion 164. This roller spring 16
5 is attached to the sub-frame 140 by locking both ends thereof to the hooking portions 144 and 144 (see FIG. 9) formed on the inner surface of the sub-frame 140. Therefore, the idle roller holder 161 is constantly urged in the direction of arrow a1 in FIG. 5 by the roller spring 165. Cam 12 formed on
Its movement is restricted (by abutting against 3). The biasing force of the roller spring 165 is set smaller than the biasing force of the pad spring 156. Therefore, the idle roller 160 does not push down the separation pad 150.

On the other hand, a cam follower 166 is formed above one side surface of the idle roller holder 161, and the cam follower 166 comes into contact with and separates from the cam 123 (see FIGS. 3 to 5) formed on the bush 122 described above. As a result, the idle roller holder 161 moves in the direction of arrow a1 or a2, and therefore the idle roller 160 also moves in the direction of arrow a1 or a2. That is, in this paper feeding device, the idle roller retracting mechanism is composed of the idle roller holder 161 and the cam 123, and the operation of the cam 123 causes the leading end of the paper to be fed to separate the pad 150. And the idle roller 160, the idle roller 160 is separated from the separation pad 150, and after the leading edge of the sheet passes between the separation pad 150 and the idle roller 160, the arc portion 121a of the paper feed roller 121 The idle roller 160 is separated from the separation pad 15 before the contact between the separation pad 150 and the separation pad 150 is released.
The shape of the cam 123 is configured so as to be brought into contact with 0.

In FIGS. 3, 4, 9, and 10, reference numeral 180 is a paper return lever.

This paper return lever 180 has a base portion 1
81 is formed in a tubular shape having a C-shaped cross section, and by utilizing its elasticity, the tubular base portion 181 is fitted to the shafts 145a and 145b formed in the subframe 140, thereby rotating the subframe 140. It is possible to install. A small diameter portion 181a is formed on the tubular base portion 181, and the torsion spring 18 is attached to the small diameter portion 181a.
2 is attached (the small diameter portion 181a is the torsion spring 18).
Second coil portion 182a). One arm 182b of the torsion spring 182 is inserted into a hole 183 formed in the paper return lever 180 and locked by the lever 180, and the other arm 182c is formed at both ends of receiving grooves 146, 146 formed in the subframe 140. Is supported and the central portion is hooked on the hook 147 to be locked to the sub-frame 140. Therefore, the lever 18
0 is in the neutral position shown in FIGS. 3 and 9 when no external force acts on it, but when an external force (an external force of the disk 124 of the bush 122 described later or an external force of the fed sheet) acts, the spring 182 is attached. When it rotates clockwise or counterclockwise in FIG. 3 against the force and the external force stops acting, it returns to the neutral position by the urging force of the spring 182.

As shown in FIG. 4, the bush 122 includes:
The disk 124 is placed at a position corresponding to the paper return lever 180.
Are integrally formed. The disk 124 is shown in FIG.
As shown in FIG. 11 and FIG. 11, a recess 124a is provided, and the paper return lever 180 at the neutral position described above is inserted into the recess 124a. Therefore, when the bush 122 rotates (when the paper feeding roller shaft 110 rotates), the corner portion 124b or 124c of the disk 124 contacts the lever 180, which causes the lever 180 to rotate clockwise or counterclockwise in FIG. Move. When rotated in the clockwise direction, the paper is pushed back as will be described later, and at this time, the separating pad 150 described above is separated from the idle roller 160 by the separating mechanism described below. There is.

The separating mechanism is mainly composed of the paper return lever 180 and the separating lever 190 (FIG. 1) incorporated in the lower surface of the pad supporting portion 153 of the separating pad holder 151.
2)) and.

12 (a) and 12 (b) show a separation lever 190.
FIG. 7 is a perspective view showing a state in which the above is incorporated into a separation pad holder 151. In addition, in this figure, the top and bottom are drawn upside down in order to make it easy to understand the assembled state.

The separating lever 190 has a shaft 191, a spring receiving portion 192, and a projecting piece 193.

On the other hand, the separation pad holder 151 has a bearing hole 151a and a bearing groove 151b, and a window 151c.
And spring receiving holes 151d, 151d are formed.

The separating lever 190 has its projection 193 inserted through the window 151c so that the shaft 191 receives the bearing hole 1.
The separation pad holder 151 is attached to the separation pad holder 151 so as to be rotatable around the shaft 191 by being fitted in the bearing groove 151b and the bearing groove 151b.

In FIG. 13B, reference numeral 194 denotes a coil spring, which is formed by partially increasing the winding diameter.
4a is formed.

The coil spring 194 is attached to the separation pad holder 151 by engaging both ends thereof with the spring receiving holes 151d, 151d, so that the spring receiving portion 192 of the spacing lever 190 is pressed downward in FIG. Has become. Therefore, the spacing lever 190 is biased by the coil spring 194, and the protrusion 193 thereof is normally in contact with the lower edge 151f (see FIG. 8) of the window 151c of the separation pad holder 151 (see FIGS. 3 and 4). But one piece
93 is rotatable within a range in which it can move within the window 151c. Note that 151e is a protrusion that engages with the step portion 194a and prevents the coil spring 194 from coming off.

On the other hand, as shown in FIG. 10, a protrusion cam 184 is formed on the paper return lever 180 described above, and the separation pad holder 151 is a sub-frame as shown in FIGS. 3, 4 and 9. When it is assembled into the cam 140, the protruding piece 193 of the separation lever 190 causes the protruding cam 18 to move.
It is designed to be positioned in the rotation orbit of No. 4. Therefore, as will be described later, when the paper return lever 180 rotates clockwise in FIG. 3, the protruding cam 184 causes the protruding piece 193 to move.
, Which causes the pad 150 to be pushed down and separated from the idle roller 160.

In FIGS. 1 and 3, reference numeral 200 denotes a synthetic resin sheet as a biasing member. This sheet 20
The upper end 201 of 0 is fixed to the guide 171 fixed to the cover 170 of the paper feed roller. In the free state, the sheet 200 is in a straight line state as shown by a chain double-dashed line in FIG. 3, but its lower end 201 is brought into contact with the upper surface Pc of the sheet P on the hopper 130 so as to be shown by a solid line. It is designed to bend. Conversely, this sheet 200 urges the sheets P stacked on the hopper 130 toward the sheet supporting surface 130a of the hopper 130.

The sheet feeding device of this embodiment is provided with a hopper holding mechanism for restricting the rotation of the hopper 130, in addition to the above-mentioned hopper cam 135 (see FIG. 1).

The hopper holding mechanism mainly consists of the holding lever 2
10 (see FIGS. 3 and 13).

In FIG. 3, reference numeral 102 denotes a pin projecting from the side wall 101 (see FIG. 1) of the frame 100, and the holding lever 210 is rotatably attached to the side wall 101 by this pin 102. A tension spring (not shown) is provided between the rear end 211 of the holding lever 210 and the side wall 101. The tension spring always urges the holding lever 210 in the clockwise direction in FIG. Since the hopper cam 135 is located on the rotation track, it is rotated counterclockwise when the tip 212 contacts the hopper cam 135 as shown in FIG. A protrusion 213 is formed in the middle of the holding lever 210, and the protrusion 213 can be engaged with and disengaged from the recess 138 formed at the side end of the hopper 130. That is, when the holding lever 210 rotates in the clockwise direction, the protrusion 213 engages with (enters) the recess 138 and the hopper 1 moves.
When the upward movement of 30 (clockwise rotation in FIG. 3) is restricted and the holding lever 210 rotates counterclockwise, the projection 213 is removed from the recess 138 and the hopper 130 can be moved upward. The hopper holding mechanism is provided on both sides of the hopper 130.

Next, the operation of the above-described paper feeding device will be described.

First, the standby state will be described.

During standby, as shown in FIG. 3, the hopper 130 is pushed down because the cam follower 134 of the hopper 130 is in contact with the hopper cam 135 (see FIG. 5).

The paper feed roller 121 has a linear portion 121b.
Is in a state of facing the paper P, and the paper feed roller 12
1 does not contact the paper P.

Therefore, in this state, the paper P can be easily set on the hopper 130.

The separation pad holder 151 (that is, the separation pad 150) is biased in the clockwise direction in FIG. 3 by the pad spring 156 (see FIG. 5), but as shown in FIG. By the contact, the rotation is restricted, and it stops at the position shown in FIGS. 3 and 5. Therefore, the biasing force of the pad spring 156 does not act on the idle roller 160. Further, at this time, the separation pad 150 has the arc portion 121 of the paper feed roller.
It is located in the rotation orbit of a.

The cam 123 of the bush 122 and the cam follower 166 of the idle roller holder 161 are not in contact with each other. Therefore, the idle roller 160 is in contact with the separation pad 150 by the urging force of the roller spring 165.

The sheet return lever 180 is in the neutral position and is in the recess 124a of the bush 122.

Projecting cam 184 of paper return lever 180
And the protrusion 193 of the separation lever 190 are not in contact with each other or are in slight contact with each other.

The protruding piece 193 of the separating lever 190 is in contact with the lower edge 151f of the window 151c of the separation pad holder 151.

The tip end 212 of the holding lever 210 of the hopper holding mechanism is in contact with the hopper cam 135, so that the projection 213 of the holding lever 210 has the projection 213.
It is in a state of being removed from the concave portion 138.

Next, the paper returning operation and the paper feeding operation will be described.

(I) In this paper feeding device, first, the paper returning operation is performed.

However, for convenience of explanation, it is easier to understand the paper returning operation after the paper feeding operation described in the following (ii) is performed, so that it will be described later.

(Ii) In FIG. 3, the paper feed roller shaft 11
0 starts rotating clockwise. Therefore, the paper feed roller 121, the bush 122, and the hopper cam 135
Also starts rotating.

(Iii) As shown in FIG. 14, the paper feed roller 121, the bush 12 together with the paper feed roller shaft 110.
2. When the hopper cam 135 rotates by a predetermined angle and the contact between the hopper cam 135 and the cam follower 134 of the hopper 130 is released, the hopper 130 is momentarily pushed up by the hopper spring 133 (see FIG. 5) and the paper P is also pushed up. Then, the uppermost sheet P1 is fed to the sheet feeding roller 121.
Is pressed against the circular arc portion 121a. Since the hopper 130 and the paper P are momentarily pushed up, even if the upper paper comes off the support surface 152, it hardly descends, and the paper is sandwiched between the hopper 130 and the paper feed roller 121 as shown in the figure.

The separation pad holder 151 (that is, the separation pad 150) is in the same state as the standby state described above. The cam 123 of the bush 122 and the cam follower 166 of the idle roller holder 161 are not yet in contact with each other, and the idle roller 160 is in contact with the separation pad 150 by the urging force of the roller spring 165. The paper return lever 180 is rotated by the bush 122 so that the disk 12 is rotated.
It is pushed by the corner portion 124c (see FIG. 3) of No. 4 and rotates in the counterclockwise direction to come out of the recess portion 124a so that the tip thereof is along the peripheral surface 124d of the disc 124. Therefore, the projection cam 184 of the paper return lever 180 is completely separated from the protrusion 193 of the separation lever 190. The separation lever 190 and the holding lever 210 remain in the same state as the standby state.

(Iv) Further, as the paper feed roller shaft 110 continues to rotate, the arc portion 121a of the paper feed roller 121 and the uppermost paper P1 are in contact with each other as shown in FIG. Paper P1 is separation pad 150
Sent to. At this time, the paper P2, which is next to the paper P1, is adsorbed by the action of static electricity, or the frictional force acts between the paper P1 and the paper P2. However, the leading edge P2a of the sheet P2 is separated by the separation pad 15
When it hits 0, its movement is hindered and it can be temporarily separated from the sheet P1. Similarly, even if the lower-order sheet P3 or the like is sent, it can be separated in the same manner. In addition, as you can see from now on, "the next paper"
In addition, the lower-order sheet P3 and the like are included, but in order to avoid complication of the description, the term "the lower-order sheet P3 and the like" is simply included unless necessary. To

At this time (the time shown in FIG. 15), the slope 123a of the cam 23 of the bush 122 contacts the cam follower 166 of the idle roller holder 161, but the leading edge P1a of the uppermost sheet P1 is still separated from the idle roller 160. The contact portion T with the pad 150 is not reached. The contact portion T is an arc portion 121 of the sheet feeding roller 121.
a coincides with the contact portion between the separation pad 150 (see FIG. 1).
8).

The other members are described in (ii) above.
It remains in the same state as i).

(V) Further, as the paper feed roller shaft 110 continues to rotate, as shown in FIG.
The arcuate portion 121a of 21 presses the separation pad 150 via the uppermost sheet P1. Thereby, the separation pad 1
50 is pressed down in the direction of arrow b1 against the urging force of the pad spring 156, and at the same time, the urging force of the pad spring 156 pinches the uppermost sheet P1 with the arc portion 121a of the sheet feeding roller 121. That is, the paper P1 is sent while being pinched between the paper feed roller 121 and the separation pad 150. At this time, as described above, the next-order paper P2 may be likely to be sent together with the paper P1, but as described above, the friction coefficient between the paper feed roller 121 and the paper is μ1, and the separation pad 150 is If the coefficient of friction with the paper is μ2 and the coefficient of friction with the paper is μ3, then μ1>μ2> μ3.
As the sheet P1 and the sheet P2 are pressed by the arc portion 121a of the sheet feed roller and the separation pad 150 as the sheet 21 rotates, the movement of the sheet P2 is hindered by the frictional force between the sheet P2 and the separation pad 150. And the paper P is secondarily
Only the paper P1 is separated from the paper P1.

At this point (at the point shown in FIG. 16),
The cam follower 166 of the idle roller holder 161 is
The cam 123 is pushed up by the inclined surface 123a of the cam 123 and rides on the arc surface 123b of the cam 123. As a result, the idle roller 160 moves in the direction of arrow a2 and is separated from the separation pad 150, but the leading edge P1a of the uppermost sheet P1 is still idle roller 160.
Does not reach the contact portion T (see FIG. 15) between the separation pad 150 and the separation pad 150.

That is, when the leading edge P1a of the paper P1 to be fed passes between the separation pad 150 and the idle roller 160, the idle roller 160 has already been separated from the separation pad 150. Becomes

The other members are described in (ii) above.
It remains in the same state as i).

(Vi) By further continuing the rotation of the paper feed roller shaft 110, the paper P1 is further fed while being pinched by the paper feed roller 121 and the separation pad 150, as shown in FIG. The paper P1 is fed by rotating the paper return lever 180 counterclockwise, and the paper return lever 180 is rotated counterclockwise according to the paper P1 until the rear end of the paper P1 passes.

At this time (the time shown in FIG. 17), the cam follower 166 of the idle roller holder 161 has the cam 1
It is located near the end of the circular arc surface 123b of 23.

At this point, the paper feed roller shaft 110
Of the hopper cam 135 shown in FIG.
7, the tip 212 of the holding lever 210 of the hopper holding mechanism is disengaged from the hopper cam 135, and therefore, the protrusion 213 of the holding lever 210 of the hopper 130 is about to rotate clockwise in FIG. Front 13
By abutting against 9, the rotation in the clockwise direction is restricted (see the phantom line in FIG. 17).

The other members are described in (ii) above.
It remains in the same state as i).

(Vii) As the paper feed roller shaft 110 continues to rotate, as shown in FIG.
Is further fed while being pinched by the paper feed roller 121 and the separation pad 150.

At this point (the point shown in FIG. 18), the cam follower 166 of the idle roller holder 161 has the cam 1
23 slides down on the other inclined surface 123c, and thus the idle roller 1 is driven by the biasing force of the roller spring 165.
60 abuts the separation pad 150. However, at this point, the arc portion 121a of the paper feed roller 121 still has the paper P
The separation pad 150 is being pressed via 1.

That is, the arc portion 12 of the paper feed roller 121.
Before the contact between the sheet 1a and the separation pad 150 via the sheet P1 is released, the idle roller 160 moves the separation pad 150
Will come into contact with.

The other members are as described in (vi) above.
However, the hopper 130 is pushed down by the hopper cam 135.

(Viii) Further, the paper feed roller shaft 110 rotates (just rotates once), and as shown in FIG. 19, the hopper 130 is completely pushed down by the hopper cam 135 and is in the standby state (the state shown in FIG. 3). Return to.

However, at this point, the paper P1 is not completely removed from the paper feeding device.

Therefore, until the rear end of the sheet P1 passes through the contact portion T between the separation pad 150 and the idle roller 160, the load is applied to the contact portion T (the state of being pulled rearward). Then, the sheet is conveyed by the conveying rollers 2 and 3 shown in FIG.

In this case, the idle roller 160 is urged by the roller spring 165 toward the separation pad 150 to pinch the paper P1 with the separation pad 150. This is prevented even if the paper P2 tries to descend due to its own weight, is attracted to the paper P1 by the action of static electricity, or is sent together with the paper P1 due to the frictional force between the paper P1 and the paper P1.

(Ix) After the trailing edge of the sheet P1 fed and conveyed as described above is removed from the sheet feeding device, the sheet feeding operation is performed again if necessary. Since the hopper 130 of the paper device is inclined and a plurality of paper sheets P are set on the hopper 130 in a stacked state, once the paper feeding operation is performed as described above, as shown in FIG. The leading edge P2a of the second sheet P2 is the separation pad 1
It is in a lowered state until it is located near the contact portion T between the idler roller 160 and the idle roller 160. If the paper is a slippery film or the like, the tip P2a of the film may pass through the contact portion T. Therefore, if the paper feeding operation is repeated in this state, the next paper P3 or the like further enters between the paper feed roller 121 and the separation pad 150, and the next paper P4 further enters. And the idle rollers 160 are provided, the next paper that should not be sent passes through the contact portion T between the idle roller 160 and the separation pad 150, which is the maximum. A situation may occur in which the sheets are sent (double-fed) together with the upper sheet.

Therefore, in this paper feeding device, before performing the paper feeding operation, first, as described above, the paper returning operation is performed in (i). That is, this paper returning operation is performed as follows prior to the above-mentioned operation (ii).

The paper returning operation is as follows.

(I-1) From the standby state described above (see FIGS. 3 and 19), the paper feed roller shaft 110 starts rotating (reverse rotation) in the counterclockwise direction. Therefore, the paper feed roller 121, the bush 122, and the hopper cam 135 also start reverse rotation.

As shown in FIG. 20, the paper feed roller shaft 110.
At the same time, when the paper feed roller 121, the bush 122, and the hopper cam 135 are reversed by a predetermined angle, the paper return lever 180 is pushed by the corner portion 124b of the disk 124 of the bush 122 to push back the leading edge P2a of the paper at the trailing edge 185. It rotates clockwise, and its projection cam 184 abuts the projection piece 193 of the separation lever 190 and pushes it down. The protruding piece 193 is provided with the window 151 of the separation pad holder 151.
Since it is in contact with the lower edge 151f of c, the separation pad 150 is also pushed down as a result, and the separation pad 150 is pushed by the separation roller 150 and the idle roller 160 as shown in the figure.
Will be separated from. In this way, the separation pad 15
0 is separated from the paper feed roller 121 and the idle roller 160 because, when the paper is a slippery film or the like as described above, the leading end P2a of the film has passed through the contact portion T. In such a case, the separation pad 150 and the paper feed roller 121 and the idle roller 160 are not separated from each other, and the paper P2
Even if the sheet return lever 180 pushes back the sheet, it cannot be pushed back smoothly.

The downward movement of the idle roller 160 is restricted by the cam follower 166 of the idle roller holder 161 contacting the cam 123.

At this time point (the time point shown in FIG. 20), the cam follower 134 of the hopper 130 has the hopper cam 135.
The holding lever 210 of the hopper holding mechanism is rotated clockwise with the tip 212 of the holding lever 210 disengaged from the hopper cam 135, and the projection 213 of the holding lever 210 is recessed in the hopper 130. 138 is entered.

(I-2) As the paper feed roller shaft 110 continues to rotate in the reverse direction, the paper return lever 180 further rotates clockwise as shown in FIG.
At 5, the paper P2 is pushed back. The projection cam 184 of the paper return lever 180 abuts on the projection piece 193 of the separation lever 190 and keeps pressing it down. Therefore, the separation pad 150 causes the separation pad 150 to feed the feed roller 121 and the idle roller 160.
Remains separated from.

Since the cam follower 134 of the hopper 130 is in contact with the hopper cam 135,
It remains pressed down, and the protrusion 213 of the holding lever 210 also remains in the recess 138 of the hopper 130.

(I-3) As the paper feed roller shaft 110 continues to rotate in the reverse direction, the paper return lever 180 further rotates clockwise as shown in FIG.
At 5, the paper P2 is completely pushed back. That is, the paper return lever 180 pushes back the paper P2 so that the front end P2a of the paper P2 reaches the rear of the support surface 152. As a result, the paper sheet P2 is moved by its own weight and the sheet 200
Urging the paper P (that is, the paper P2) toward the paper support surface 130a of the hopper 130, the paper P is completely returned (dropped) onto the hopper 130.

At this point, the hopper cam 135 has the hopper 1
Since the hopper 130 tries to move up because it is disengaged from the cam follower 134 of 30, the hopper 130 does not move up but moves down because the projection 213 of the holding lever 210 has entered the recess 138 of the hopper 130. (The state shown in FIG. 22) remains as it is. Therefore, the dropping of the paper is surely performed. In addition, such a hopper 13
The holding operation of 0 changes the shape of the hopper cam 135, that is, even if the paper feed roller shaft 110 reverses as shown in FIG. 22, the shape is still in contact with the cam follower 134 (shape indicated by imaginary line 135 ′). It is also possible by However, with such a shape, the hopper 130 is pushed down quickly (lowers before reaching the state shown in FIG. 17) at the time of the above-described paper feeding operation, and a sheet is pushed by the pushing force of the hopper 130. This is not desirable because the contact period with the sheet feeding roller 121 may become insufficient and the sheet feeding operation itself may not be performed reliably.

When the paper return lever 180 completely rotates in the clockwise direction, the projection cam 184 is disengaged from the protrusion 193 of the separation lever 190. Therefore, the separation pad 150 is allowed to move upward, but its upward movement is restricted by contacting the paper feed roller 121 at this point.

In this paper feeding device, the paper P2 is completely returned to the hopper 130 as described above, but at least the leading end P2a of the next paper P2 is formed by the idle roller 160 and the separation pad 150. If it is pushed back so that it is located rearward of the contact portion T, the above-mentioned cumulative entry is prevented.

After the paper return operation as described above is performed,
The paper feed roller shaft 110 rotates in the normal direction, and after the standby state described above, the paper feed operation after (ii) is performed. When the paper feed roller shaft 110 rotates in the forward direction after the paper return operation is performed, the paper return lever 180 causes the paper return lever 180 to rotate by the biasing force of the torsion spring 182 and the corner portion 124c of the disk 124 of the bush 122.
It is rotated counterclockwise by being pushed by, but at this time, the projection cam 184 of the paper return lever 180 is pressed.
Only contacts the lower surface of the protruding piece 193 of the spacing lever 190 and pushes it up (rotates the spacing lever 190 counterclockwise) to pass.

According to the paper feeding device as described above, the following operational effects can be obtained.

(A) A sheet feeding roller 121 having an arcuate portion 121a and a straight portion 121b, which is normally rotated during a sheet feeding operation, and is in contact with the arcuate portion 121a of the sheet feeding roller 121. A plurality of sheets of paper P to be fed are stacked, and a hopper 130 that presses the paper P toward the paper feed roller 121 when the paper feed roller 121 rotates normally, and a rotation path of the arc portion 121 a of the paper feed roller 121. Located, pad biasing means 1
Separation pad for separating the paper P1 to be sent by the paper feed roller 121 from the next paper P2 by pressing the paper P between the arc portion 121a and the paper feed roller 121 urged by 56. Since 150 is provided, only the uppermost sheet P1 is fed during the sheet feeding operation.

(B) Since the sheets P are stacked on the hopper 130 in an inclined state, this sheet feeding device can reduce the installation area.

Since the sheets P are stacked in an inclined state on the hopper 130, when the uppermost sheet P1 is fed,
The next paper P2 also descends toward the paper feed roller 121, but when the arcuate portion 121a of the paper feed roller 121 and the separation pad 150 are in pressure contact with each other, this pressure contact portion causes the next paper P2 to move. The descent is inhibited (see FIG. 15, etc.).

Since the paper feed roller 121 is substantially D-shaped in a side view having an arcuate portion 121a and a straight portion 121b, the pressure contact between the arcuate portion 121a and the separation pad 150 is released in the process of one rotation of the paper feed roller 121. Then, when the linear portion 121b comes into a state of facing the separation pad 150, that is, when the pressure contact portion disappears, the next paper P2 tries to descend, but at this time, the idle roller 160 causes the separation pad 15 to move.
Since it comes into contact with 0 and prevents the next paper P2 from descending,
The lowermost sheet P2 is prevented from descending (see FIG. 19).

Then, after the trailing edge of the uppermost sheet P1 fed by the sheet feeding roller 121 has passed, the sheet return lever 180 is rotated rearward so that the leading edge P2a of the next-order sheet P2 is moved. Since the next-order sheet P2 is pushed back toward the rear so as to be positioned behind the contact portion T between the idle roller 160 and the separation pad 150,
Although the paper feed roller 121 is a D-shaped roller and the paper P is stacked in an inclined state, the next paper P2
The situation where the paper gradually enters (cumulatively) into the pressure contact portion between the paper feed roller 121 and the separation pad 150 and the paper cannot be separated will not occur.

(C) Further, according to this paper feeding device, when the separation pad 150 does not press the paper between the separation pad 150 and the arc portion 121a of the paper feeding roller 121, the separation pad 150 facing the paper feeding roller 121 is moved. A pin 14 as a pad restricting means for restricting the movement, which is different from the idle roller 160.
1 is provided, the urging force of the pad urging means 156 is received by the pad regulating means 141.

Therefore, the contact force between the idle roller 160 and the separation pad 150 is obtained by the roller urging means 165, and the urging force by the roller urging means 165 is smaller than the urging force by the pad urging means 156. The paper clamping force can be made smaller than that of the conventional device.

More specifically, in the conventional sheet feeding device shown in FIG. 28, as described above, the sheet feeding roller 40 makes one rotation during the sheet feeding operation, and the state shown in FIG.
Becomes a state in which the separation pad 43 is not pressed), the urging force F1 of the spring 44 of the separation pad 43 is set to be larger than the urging force F2 of the spring 48 of the movable idle roller 47. The movable idle roller 47 is stopped in a state of being pushed up until its shaft 47a comes into contact with the upper end of the long groove 41a.

That is, in the conventional paper feeding device, the paper P1
Is separated by the urging force F1 of the spring 44 of the separation pad 43 from the separation pad 43 and the movable idle roller 4
In the state of being clamped between the sheet and the sheet 7, the sheet is conveyed by the conveying rollers 2 and 3 shown in FIG. 26, for example.

The separation pad 43 is for preventing the paper from being fed when two or more papers are fed by pinching the paper with the arc portion 40a of the paper feed roller 40 as described above. Therefore, the urging force F1 needs to be set relatively large (at least larger than the urging force F2 of the movable idle roller 47 as described above).

In the conventional sheet feeding device, since the rear portion of the sheet P1 is pinched by the relatively large urging force F1, the load on the pinching portion is large.
Moreover, if the flexible idle roller 47 is used to prevent the above-described cumulative entry of the next sheet, the urging force F2 of the movable idle roller 47 must be increased.

On the other hand, the sheet feeding device S of this embodiment
According to F, the idle roller 160 that restricts the movement of the separation pad 150 toward the paper feed roller 121 when the separation pad 150 does not press the paper P1 between the separation pad 150 and the arc portion 121a of the paper feed roller 121 is described. Another pad regulation means 1
Since 41 is provided, the urging force of the pad urging means 156 is received by the pad regulating means 141.

Therefore, the contact force between the idle roller 160 and the separation pad 150 is obtained by the roller urging means 165, and the urging force by the roller urging means 165 is smaller than the urging force by the pad urging means 156. That is, the next paper P2 is the paper return lever 18
Since a relatively small biasing force that can prevent the movement of the next paper P2 can be prevented so as not to reach the position where it cannot be pushed back by the rotation of 0, the idle roller 160 and the separation pad 150 are provided. The nipping force of the paper due to and can be made smaller than that in the conventional apparatus, and as a result, the load acting on the paper P1 after feeding the uppermost paper P1 can be reduced.

As described above, according to the sheet feeding device SF, the sheets P stacked and held in the inclined state are reliably separated one by one using the separation pad method without increasing the load (back tension). Can be delivered.

(D) According to this paper feeding device SF, when the paper return lever 180 pivots backward and pushes back the next paper P2 backward, the separation pad 150 is separated from the idle roller 160. Since it has a mechanism,
The second-order sheet P2 can be pushed back smoothly.

(E) The hopper 130 is a hopper that separates the paper P stacked on the hopper 130 from the paper feed roller 121 when the paper return lever 180 rotates rearward. A support surface 152 that supports the leading edge of the sheets stacked on the hopper 130 is provided in the front of the sheet feeding direction, and the sheet return lever 180 has the leading edge P2a of the next-order sheet P2 on the supporting surface 152.
Since the next-order sheet P2 is pushed back so as to reach the rear of the sheet, the leading edge P of the pushed-back next-order sheet P2 is reached.
2a will be supported by the support surface 152.

Therefore, the above-mentioned cumulative entry of the second-order sheet P2 is surely prevented.

(F) Since the sheet P stacked on the hopper 130 is provided with the sheet 200 as an urging member for urging the sheets P toward the sheet supporting surface 130a of the hopper 130, the sheet 200 is pushed back to the next position. The paper P2 of the
Will be dropped on the hopper 130 by
The leading edge of the next sheet P2 pushed back is surely supported by the support surface 1
It will be supported by 52.

Therefore, the above-mentioned cumulative entry of the next-order sheet P2 can be prevented more reliably.

(G) The paper feed roller 121 reverses once before making one revolution, and by this reverse rotation, the paper return lever 18
Since 0 is rotated backward, the paper is fed by the paper feed roller 121 for some reason before the paper feed operation is started.
Even if it gets in between the separation pad 150 and
This can be reliably returned once.

Therefore, for some reason, if the paper feed operation is performed as it is while the paper is inserted between the paper feed roller 121 and the separation pad 150, a trouble (for example, a misfeed of the paper) may occur. It can be prevented.

(H) When the leading edge of the paper P1 to be fed passes between the separation pad 150 and the idle roller 160, the idle roller 160 is separated from the separation pad 150 (see FIG. 16), and the paper P1 After the leading edge passes between the separation pad 150 and the idle roller 160, before the contact between the arcuate portion 121a of the paper feed roller 121 and the separation pad 150 via the sheet is released, the idle roller 1
Since the idle roller retracting mechanism for bringing the 60 into contact with the separation pad 150 (see FIG. 18) is provided, the following operational effects are obtained.

That is, during the paper feeding operation, the paper feeding roller 121
Is rotated and the uppermost sheet P1 is fed, and when the leading edge of the sheet P1 tries to pass through the contact portion between the arcuate portion 121a of the sheet feed roller 121 and the separation pad 150, the idle roller 160 moves the separation pad 150. When the idle roller 16 is pressed against the separation pad 150,
0 becomes a resistance against the sheet P1 which is about to pass.

On the other hand, according to the sheet feeding device of the embodiment, when the leading end P1a of the sheet P1 to be fed passes between the separation pad 150 and the idle roller 160, the idle roller 160 is separated from the separation pad. Since the retracting mechanism that separates the sheet from 150 is provided, the idle roller 160 does not become a resistance against the sheet that is about to pass.

In the retracting mechanism, after the leading edge of the paper P1 passes between the separation pad 150 and the idle roller 160, the arc portion 121a of the paper feed roller 121 and the separation pad 1 are separated.
Since the idle roller 160 is brought into contact with the separation pad 150 before the contact with the sheet 50 via the paper is released, the contact between the arc portion 121a of the paper feed roller 121 and the separation pad 150 via the paper is released. And the top paper P1
At the same time, the next paper P2 will not be sent.

(I) Since the idle roller retracting mechanism is provided on the shaft 110 of the paper feeding roller and is operated by the cam 123 that rotates together with the shaft 110, the structure can be simplified. For example, the structure can be simple as compared with the case where it is operated by a solenoid or the like.

As described above, Japanese Patent Application No. 8 previously filed by the applicant
Although the sheet feeding device of No. 298043 has been described, the embodiment of the present invention is an improvement of this, and therefore the improvement will be described.

FIG. 23 is a side view showing an essential part of this embodiment, FIG. 24 is a view mainly showing an idle roller holder, (a) is a front view with an idle roller attached, and (b) is the same. A side view, (c) is a front view of only the idle roller holder, and (d) is a side view of the same. In these figures, the same or corresponding parts as those described above are designated by the same reference numerals.

The first main feature of this embodiment is shown in FIG.
3, the paper feed roller 121 of the separation pad 150
The opposite surface 150a to and is curved in a concave shape with respect to the sheet feeding roller 121.

The second main characteristic is the paper feed roller 121.
Is located between the position of the paper return lever 180 (position indicated by imaginary line 180) and the contact position T between the separation pad 150 and the idle roller 160 when the uppermost paper P1 is fed by the separation pad 150. A paper path R is formed between the paper and the paper P that is about to pass through the path R.
2 (see FIG. 25B) is provided with a guide 167 that comes into contact with the tip portion P2b when the tip portion P2b is curved toward the paper feed roller.

The separation pad 150 is a thin plate having flexibility as shown in FIG. 7. In this embodiment, as shown in FIGS. 23 and 25, the pad support in the separation pad holder 151 'is supported. Top surface 153 of section 153 '
By bending a into a concave shape, the upper surface 153a
The separation pad 150 attached to is curved, and the surface 150 a facing the sheet feeding roller 121 is curved in a concave shape with respect to the sheet feeding roller 121.

The upper surface 153a of the pad support portion 153 'is
Contact part T between separation pad 150 and idle roller 160
It is curved only on the downstream side (left side in the figure) of the sheet in the sheet feeding direction, and is not curved concavely on the upstream side (right side in the figure). Therefore, the surface 150a of the separation pad 150 facing the paper feed roller is also curved in a concave shape only on the downstream side of the contact portion T in the paper feeding direction.

As shown in FIG. 24, the guide 167 is used for the idle roller holder 1 that supports the idle roller 160.
It is provided integrally with 61.

The guide 167 guides the upper surfaces of both side portions of the sheet that has passed between the separation pad 150 and the idle roller 160, and the surface 167a facing the separation pad has a sheet feeding roller of the separation pad 150. It is curved so as to be substantially parallel to the facing surface 150a facing 121. The surface 150a of the separation pad 150 facing the paper feed roller
The distance between the guide 167 and the separation pad 167a facing the separation pad may be narrowed toward the downstream side (the left side in the drawing) of the sheet in the sheet feeding direction.

According to such an embodiment, the following operational effects can be obtained in addition to the operational effects (a) to (i) described above.

(J) FIG. 23 shows how the uppermost sheet P1 is fed by the paper feeding operation, and the sheet P1 is further conveyed by the conveying rollers 2 and 3 in the subsequent stage.

[0227] In this way, the fed uppermost sheet P1
However, when it is conveyed by the conveying rollers 2 and 3 in the subsequent stage, as described above, the second-order sheet P2 is adsorbed to the uppermost sheet P1 by the action of static electricity, or Due to the frictional force acting on the sheet, the next-order sheet P2 may try to be fed together with the highest-order sheet P1, and this tendency is promoted when the sheet is in an inclined state.

The movement of the next-order sheet P2 is restricted by the idle roller 160 being pressed against the separation pad 150, but this pressing force (in this embodiment, the biasing force by the roller spring 165) is increased. Then, the back tension for the sheet P1 conveyed by the conveying rollers 2 and 3 increases, which is not desirable, as described above.

Therefore, it is desirable to reduce the pressure contact force between the idle roller 160 and the separation pad 150, but if this force is reduced, the next paper P2 will easily pass through the pressure contact portion T. And the top paper P
1 rear end P1b is the front end 180a of the paper return lever 180.
If the leading end P2a of the next paper P2 passes through the leading end 180a of the paper return lever when the paper return lever 180 pivots rearward after passing through the paper return lever 180, the next paper P2 is returned. It will not be pushed back by the lever 180.

On the other hand, according to the paper feeding device of this embodiment, as shown in FIG.
Since the surface 150a facing the paper feeding roller is concavely curved with respect to the paper feeding roller, even if the next paper P2 passes through the pressure contact portion T between the idle roller 160 and the separation pad 150, the tip thereof It becomes easy for P2a to contact the curved surface (150a) of the separation pad 150.

Therefore, even if the pressure contact force between the separation pad 150 and the idle roller 160 is not so large,
A situation in which the next-order sheet P2 moves together with the highest-order sheet P1 is unlikely to occur, and as a result, when the sheet return lever 180 rotates rearward, the leading end P2a of the next-order sheet P2 returns to the sheet. A situation in which the tip 180a of the lever 180 has already passed is unlikely to occur.

That is, according to the sheet feeding device of this embodiment, it is possible to reduce the back tension without increasing the back tension (the back tension can be made smaller than the back tension in the sheet feeding device having the basic structure described above. However, it is possible to make it difficult for the leading edge P2a of the next sheet P2 to pass through the leading edge 180a of the sheet return lever, and as a result, the stacked sheets P are loaded (back tension) using the separation pad method. It is possible to reliably feed the sheets one by one without increasing the number of sheets.

(K) Since the surface 150a of the separation pad 150 facing the paper feed roller is curved downstream of the contact portion T between the separation pad 150 and the idle roller 160 in the paper feeding direction, The following effects can be obtained.

That is, since the surface 150a of the separation pad 150 facing the paper feed roller is not curved concavely on the upstream side in the feeding direction, as a result, the distance between the separation pad 150 and the paper feed roller 121 on the upstream side is increased. C (see FIG. 23) is secured, and the paper P is separated by the separation pad 15 during the paper feeding operation.
0 is more likely to be introduced between the paper feed roller 121 and
On the downstream side, as shown in FIG. 25A, since the sheet (particularly the next-order sheet P2) is pressed by the idle roller 160 toward the separation pad 150, the leading edge P2a of the next-order sheet P2. Are more likely to contact the curved surface (150a) of the separation pad 150.

Therefore, according to the sheet feeding device of this embodiment, a smooth feeding state can be obtained, and the leading end P2a of the next paper P2 is the leading end 18 of the paper return lever 180.
It becomes even more difficult for the situation of passing 0a to occur.

(L) As described above, the paper return lever 1
If the leading edge P2a of the next-order sheet P2 passes through the leading edge 180a of the sheet return lever 180 when the 80 rotates rearward, the next-order sheet P2 moves to the sheet return lever 18.
It will not be pushed back by 0, but such a situation is
This is likely to occur when the leading edge of the next sheet is curved in the direction away from the separation pad 150, that is, toward the sheet feed roller. If the leading end of the next sheet is curved toward the paper feed roller, the leading end of the sheet that has passed the contact position T between the separation pad 150 and the idle roller 160 will be separated pad 150.
This is because the contacting force does not come into contact with or does not come into contact with, and therefore the contacting force becomes small, and therefore the resistance due to the separation pad is not received or the resistance becomes small.

On the other hand, according to the sheet feeding device of this embodiment, the position of the sheet return lever 180 (see FIG. 23) and the separation pad when the uppermost sheet P1 is fed by the sheet feeding roller 121. And a contact position T between the idle roller and the idle roller, a paper path R is formed between the paper and the separation pad 150, and the leading end of the paper passing through the path R is curved toward the paper feed roller 121. Since the guide 167 that comes into contact with the leading end portion of the sheet P2 when it is in contact is provided, as shown in FIG. 25B, the next sheet P2 that has passed the contact position T between the separation pad 150 and the idle roller 160. If the tip portion P2b of the sheet is curved toward the paper feed roller, the tip portion P2b (particularly, the tip portion P2b
When a) comes into contact with the guide 167, the elastic force of the leading end portion (curved portion) P2b of the sheet P presses the separation pad 150, and as a result, the resistance of the separation pad 150 is received.

Therefore, even if the pressure contact force between the separation pad 150 and the idle roller 160 is not so large,
It becomes difficult for the next paper P2 whose front end portion is curved toward the paper feed roller to move together with the uppermost paper P1. As a result, when the paper return lever 180 rotates rearward, It becomes difficult for the leading end P2a of the second sheet P2 to pass through the leading end 180a of the sheet return lever 180.

That is, according to the paper feeding device of this embodiment, the leading edge P2a of the next paper P2 is the leading edge 1 of the paper return lever 180 without increasing the back tension.
It is possible to make it difficult for the sheet to pass through 80a, and as a result, the stacked and held sheets can be reliably fed one by one without increasing the load (back tension) by using the separation pad method.

(M) Since the surface 150a of the separation pad 150 facing the paper feed roller and the surface 167a of the guide 167 facing the separation pad are formed substantially parallel to each other, FIG.
As shown in (b), the leading end portion P2b of the next paper P2 whose leading end portion is curved toward the paper feed roller is more reliably brought into contact with the guide 167, and the resistance of the separation pad 150 is surely received. Become. It should be noted that this action is performed by the surface of the separation pad 150 facing the paper feed roller 150a and the guide 1
In the case where the interval between the separation pad 67 and the facing surface 167a is narrowed toward the downstream side in the sheet feeding direction, it can be obtained more reliably.

Therefore, even if the pressure contact force between the separation pad 150 and the idle roller 160 is not so large,
It becomes even more difficult for the next paper P2 whose front end portion is curved toward the paper feed roller to move together with the uppermost paper P1, and as a result, when the paper return lever 180 rotates backward, It is even more difficult for the leading edge P2a of the next highest sheet to pass through the leading edge 180a of the sheet return lever 180.

(N) The guide 167 is the idle roller 1
Since it is provided integrally with the idle roller holder 161 that supports 60, it is not necessary to separately provide a support member that supports this guide 167, and the structure can be simplified.

Moreover, the idle roller 160 is a member that comes into contact with the separation pad 150.
As a result of the guide 167 being integrally provided with the idle roller holder 161 that supports 60, the gap between the guide 167 and the separation pad 150 (that is, the paper path R) is appropriately formed. The action and effect of (l) and (m) described above can be obtained more reliably.

Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications can be appropriately made within the scope of the gist of the present invention.

[0245]

The paper feeding device according to any one of claims 1 to 12 can prevent the back tension from increasing.
It is possible to make it difficult for the leading edge of the next paper to pass through the leading edge of the paper return lever, and as a result,
By using the separation pad method, it is possible to reliably feed the sheets one by one without increasing the load (back tension).

[0246]

Further, according to the paper feeding apparatus of the second aspect , when the paper return lever is rotated rearward, the leading end of the next paper has passed the leading end of the paper return lever. Is more difficult to occur.

According to the paper feeding device of the third aspect , a smoother feeding state can be obtained, and a situation in which the leading edge of the next-order sheet passes the leading edge of the sheet return lever is more reliably caused. It will be difficult.

According to the sheet feeding device of the fourth aspect, it is not necessary to separately provide a supporting member that supports the guide, and the structure can be simplified.

Moreover, the above-mentioned claim 1, 2, or
The effect of the sheet feeding device described in 3 can be obtained more reliably.

According to the paper feeding device of the fifth aspect , the installation area can be reduced.

According to the sheet feeding device of the sixth aspect , the load (back tension) acting on the rear portion of the fed uppermost sheet can be further reduced.

According to the paper feeding device of the seventh aspect , it is possible to smoothly push back the next paper.

According to the paper feeding device of the eighth aspect, the cumulative entry of the next paper is prevented more reliably.

According to the sheet feeding device of the ninth aspect, the cumulative entry of the next sheet is more surely prevented.

According to the paper feeding device of the tenth aspect, a problem that may occur if the paper feeding operation is performed as it is while the paper is inserted between the paper feeding roller and the separation pad for some reason ( For example, it is possible to prevent the paper cue failure).

According to the paper feeding device of the eleventh aspect , the idle roller does not become a resistance against the paper that is about to pass.

According to the paper feeder of the twelfth aspect , the structure can be simplified.

[0259]

[Brief description of drawings]

FIG. 1 is a perspective view showing the basic configuration of an embodiment of a sheet feeding device according to the present invention.

FIG. 2 is a diagram showing an example of attaching the above-described paper feeding device to a printer, and is a partially omitted side view showing a part of the same.

FIG. 3 is a partially cut side view mainly showing a paper feeding roller unit of the paper feeding device.

4 is a sectional view taken along line IV-IV in FIG.

FIG. 5 is a cross-sectional view mainly showing a paper feed roller, a hopper, and the like of the same paper feeder.

6 is a partially omitted plan view of FIG.

FIG. 7 is a perspective view of a separation pad 150 and a separation pad holder 151 of the same paper feeder.

FIG. 8 is a perspective view of the separation pad holder 151 and the sub-frame 140 of the same paper feeder.

FIG. 9 is a perspective view mainly showing the idle roller holder 161 and the sub-frame 140 of the same paper feeding device.

FIG. 10 is the same as that of the paper feeding device, mainly the paper return lever 18;
0 is a perspective view showing 0 and the sub-frame 140.

FIG. 11: Disc 124 of bush 122 of the same paper feeder
FIG.

12 (a) and 12 (b) are the same as the separation lever 1 of the sheet feeding device.
The perspective view which shows the attachment state of 90.

FIG. 13 is a side view of a holding lever 210 of the same paper feeding device.

FIG. 14 is an operation explanatory view of the same paper feeding device.

FIG. 15 is an explanatory view of the operation of the same paper feeding device.

FIG. 16 is an explanatory view of the operation of the same paper feeding device.

FIG. 17 is an explanatory view of the operation of the same paper feeding device.

FIG. 18 is an operation explanatory view of the same paper feeding device.

FIG. 19 is an operation explanatory view of the same paper feeding device.

FIG. 20 is an operation explanatory diagram of the same paper feeding device.

FIG. 21 is an operation explanatory view of the same paper feeding device.

FIG. 22 is an explanatory view of the operation of the same paper feeding device.

FIG. 23 is a side view showing a main part of an embodiment of a paper feeding device according to the present invention.

FIG. 24 is a view mainly showing an idle roller holder of the same paper feeder, (a) is a front view with an idle roller attached, (b) is a side view of the same, and (c) is a front view of only the idle roller holder. The figure and (d) are also side views.

25 (a) and 25 (b) are diagrams for explaining the operation of the same paper feeding device.

FIG. 26 is an explanatory diagram of a conventional technique.

27A to 27E are explanatory views of a conventional technique.

FIG. 28 is an explanatory diagram of a conventional technique.

[Explanation of symbols]

P paper P1 topmost paper P2 Secondary paper R passage 121 paper feed roller 121a arc part 121b Straight part 123 cam 130 hoppers 140 subframes 141 pin 150 separation pad 150a Surface facing the paper feed roller 152 support surface 156 pad spring 160 idle roller 161 Idol roller holder 165 Roller spring 166 Cam Follower 167 Guide 167a Face facing separation pad 180 Paper return lever 190 Separation lever 200 sheets

Continuation of the front page (56) Reference JP-A-6-234437 (JP, A) JP-A-59-217538 (JP, A) JP-A-62-295842 (JP, A) JP-A-61-282237 (JP , A) JP-A-8-217280 (JP, A) JP-A-3-51235 (JP, A) Jikken 8-3396 (JP, Y2) (58) Fields investigated (Int.Cl. ⁷ , DB) (Name) B65H 3/46 B41J 13/00 B65H 3/06 330

Claims (12)

(57) [Claims] 1. A sheet feeding roller having an arcuate portion and a linear portion, which is substantially D-shaped in a side view and rotates normally during a sheet feeding operation, and the sheet feeding roller should be in contact with the arcuate portion to be fed. By stacking a plurality of sheets of paper, by pinching the paper between a hopper that presses the paper toward the paper feed roller when the paper feed roller is normally rotated, and at least the arc portion of the paper feed roller when the paper is normally rotated, The separation pad, which separates the paper to be sent by the paper feed roller from the next paper, and the separation pad, at least when the separation pad does not press the paper between the arc portion of the paper feed roller and the separation pad, An idle roller for restricting the movement of the uppermost sheet, and a rear end of the uppermost sheet fed by the paper feed roller, and then a backward rotation to cause the leading edge of the next sheet to be the idle roller. Located behind the abutment part with the separation pad So that the next sheet of paper is pushed backward, the position of the sheet return lever when the uppermost sheet is fed by the paper feed roller, and the contact between the separation pad and the idle roller A sheet path is formed between the position and the separation pad, and when the leading end portion of the sheet passing through this passage is curved toward the paper feed roller, it abuts the leading end portion. A paper feeding device comprising: a guide. 2. The surface of the separation pad facing the paper feed roller and the surface of the guide facing the separation pad are substantially parallel to each other, or the distance between the both surfaces faces toward the downstream side in the paper feeding direction. Therefore, the sheet feeding device according to claim 1 , wherein the sheet feeding device is formed narrow. 3. The surface of the separation pad facing the paper feed roller is concavely curved with respect to the paper feed roller at a position downstream of a contact portion between the separation pad and the idle roller in a paper feeding direction. 3. The paper feeding device according to claim 1, wherein the paper feeding device is provided. 4. The sheet feeding device according to claim 1, wherein the guide is provided integrally with an idle roller holder that supports the idle roller. 5. A sheet to be fed by the paper feed roller, according to claim 1, characterized in that it is laminated in an inclined state
The sheet feeding device according to any one of 4 to 4 . 6. Compared to the clamping pressure between the feed roller and the separation pad, claim 1, characterized in that the direction of the contact force is smaller between the separation pad and the idle roller
5. The sheet feeding device according to any one of 5 to 5 . 7. A separation mechanism is provided which separates the separation pad from the idle roller when the paper return lever pivots backward and pushes back the next paper toward the rear. Item 7. The sheet feeding device according to any one of items 1 to 6 . 8. The hopper is a hopper that separates the sheets stacked in the hopper from the paper feed roller when the paper return lever rotates rearward, and the hopper has a paper feeding direction. At the front, a support surface for supporting the leading edge of the sheets stacked on the hopper is provided, and the sheet return lever moves the next sheet so that the leading edge of the next sheet reaches the rear of the supporting surface. The paper feeding device according to claim 1 , wherein the paper feeding device is pushed back. 9. A urging member for urging the sheets stacked on the hopper toward a sheet supporting surface of the hopper, according to any one of claims 1 to 8.
Paper feeder described in 1. 10. The paper feed roller is a roller that normally rotates once during a paper feed operation, and reverses once before the first rotation, and the paper return lever rotates backward due to this reverse rotation. The sheet feeding device according to any one of claims 1 to 9 . 11. The idle roller is separated from the separation pad when the front end of the paper to be fed passes between the separation pad and the idle roller, and the front end of the paper is between the separation pad and the idle roller. And an idle roller retracting mechanism for bringing the idle roller into contact with the separation pad after the contact between the arc portion of the paper feed roller and the separation pad via the paper is released. sheet feeding apparatus according to any one of claims 1 to 10. 12. The sheet feeding device according to claim 11, wherein the idle roller retracting mechanism is provided on a shaft of the sheet feeding roller and is operated by a cam that rotates together with the shaft.