JPH0797072A - Sheet material feeder - Google Patents

Abstract

PURPOSE:To provide a means for feeding sheet material positively sheet by sheet with simple constitution in a sheet material feeder in a printer, a copying machine, a facsimile, or the like. CONSTITUTION:A sheet material feeder is provided with a feed roller 11 for feeding sheet material, a sheet material stacking member 15 for stacking sheet material and pressing the sheet material onto the feed roller 11 side, a separating pad 20 for pressing the sheet material fed to the feed roller 11 from the stacking member 15, a pressure release cam 25 for releasing pressure to the sheet material placed on the stacking member 15, toward the feed roller 11, and a contact release cam 25 for releasing the contact of the sheet material with the feed roller 11. The sheet material can be thereby fed sheet by sheet with light torque transmission force with constitution with a small number of part items and desirable assemblage so as to reduce cost and to improve reliability.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet material feeder for separating sheet materials one by one and feeding them in printers, copying machines, facsimiles and the like.

[0002]

2. Description of the Related Art In an image forming apparatus such as a printer, a copying machine or a facsimile, printing is performed while feeding sheet materials such as paper one by one. Hereinafter, a conventional sheet material feeding device will be described.

FIG. 7, FIG. 8 and FIG. 9 are cross-sectional views of essential parts showing the sheet feeding operation of a conventional sheet material feeding device. 1 in FIG.
Is a sheet material, 2 is a paper feed roller in which a part of a cylinder for feeding the sheet material 1 is cut out, 3 is a paper feed shaft supporting the paper feed roller 2, and a one-rotation clutch (not shown) is incorporated. Has been. Reference numeral 4 denotes a separation pad that is supported inside the apparatus main body (not shown) so as to be swingable in the direction of arrow H, and is urged toward the paper feed roller 2 by a spring 5. Reference numeral 6 denotes a separation idler roller rotatably supported by the paper feed shaft 3, which is slightly smaller than the radius of the paper feed roller 2, and when the cut portion of the paper feed roller 2 rotationally moves to the separation pad 4 side, the separation pad 4 Contact with.

Reference numeral 7 is a stacking member for the sheet material 1 whose end portion is swingably supported inside the apparatus main body (not shown), and a spring 8
Is urged toward the paper feed roller 2 side. 9a is an upper guide for guiding the conveyance of the sheet material 1, 9b is a lower guide, 1
Denoted at 0a and 10b are transport rollers for transporting the sheet material 1 separated and fed one by one by the paper feed roller 2 to an image forming means (not shown) at a downstream position in the transport direction. Here, if the frictional forces between the sheet feed roller 2 and the sheet material 1, the separation pad 4 and the sheet material 1, and the sheet materials 1 are Q, R, and S, respectively, the sizes are Q>R> S. There is.

The operation of the conventional sheet material feeding device constructed as described above will be described below. Paper feed roller 2, separation pad 4, separation idler roller 6, sheet material 1
As for the positional relationship of the sheet material 1, when the sheet material 1 is not fed or conveyed, as shown in FIG. 7, the sheet feeding roller 2 is stopped in a state where the cut-out portion of the cylinder is located at the bottom, The separation pad 4 is pressed against the separation idler roller 6 side by being urged by the spring 5. The separation idler roller 6 is also in pressure contact with the sheet material 1 stacked and stacked on the stacking member 7.

When the paper feeding operation is started, the paper feeding roller 2 first rotates in the direction of arrow G, and the paper feeding roller 2 comes into contact with the sheet material 1. Further, when the paper feed roller 2 rotates, only the uppermost sheet material 1 stacked on the stacking member 7 is fed leftward between the paper feed roller 2 and the separation pad 4 as shown in FIG.

Since the paper feed roller 2 has a one-rotation clutch incorporated therein, the paper feed roller 2 is rotated once to rotate the sheet material 1 for a predetermined distance.
Is conveyed and then stopped, and the state shown in FIG. 9 is obtained. The conveyance distance by the rotation of the paper feed roller 2 is the conveyance roller 10a,
It is set longer than the distance between 10b and the paper feed roller 2. The sheet material 1 is conveyed by the paper feed roller 2 and then conveyed by the conveyance rollers 10a and 10b into the image forming means (not shown). At this time, the sheet material 1 is pushed by the separation pad 4 and is in pressure contact with the separation idler roller 6. However, since the separation idler roller 6 rotates as the sheet material 1 moves, it does not affect the conveyance of the sheet material 1. After the conveyance of the sheet material 1 is completed, the sheet feeding roller 2 is again provided.
Starts to rotate, and paper feeding is repeated as described above.

[0008]

However, in the configuration of the above-mentioned conventional sheet material feeding device, the sheet feeding roller 2 and the conveying roller 1 are used for feeding, separating and conveying the sheet material 1.
Two feeding means 0a and 10b are required, and there is a problem that the cost is increased by the increase in the number of parts and the size of the apparatus is increased. Further, since the drive transmission of the sheet feeding roller 2 is switched by disposing a one-rotation clutch on the sheet feeding shaft 3 of the sheet feeding roller 2, the sheet feeding roller 2 conveys the sheet material 1 in the one rotation clutch. Is required to have a necessary transmission force, which results in a problem that the one-rotation clutch becomes large in size and cost, and that a high transmission force is required, resulting in a decrease in reliability. It was

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a sheet material feeding device capable of reliably feeding sheet materials one by one with a simple structure having a small number of parts.

[0010]

To this end, according to the present invention, a sheet feeding roller for feeding a sheet material, a driving means for rotating the sheet feeding roller, and a sheet material stacked on the circumference of the sheet feeding roller. Stacking means for pressing the sheet material against the surface, a separation pad for bringing the sheet material sent out from the stacking means into contact with the peripheral surface of the paper feeding roller by rotation of the paper feeding roller, and the paper feeding roller of the stacking means A sheet material feeding device is composed of a pressure releasing means capable of releasing the pressing to the side and an abutting releasing means capable of releasing the contact of the sheet material fed from the stacking means with the sheet feeding roller. .

[0011]

According to the present invention, the sheet material stacked on the stacking means can be reliably delivered one by one by the intermittent switching of the pressing of the sheet material to the sheet feeding roller, and the light torque transmission. The force allows the sheet material to be fed.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view of a main portion of a sheet material feeding device according to an embodiment of the present invention, and FIGS. 2, 3, 4, 5, and 6 show a sheet material feeding device according to an embodiment of the present invention. It is a principal part sectional view which shows a paper feeding operation. In FIGS. 1 and 2, 11 is fixed to a shaft 12 and is a paper feed roller for feeding the sheet material 1 by being rotationally driven integrally with the shaft 12,
A driving roller 3 is fixed to a driving source (not shown) and drives the shaft 12. Reference numeral 14 is a stacking means for stacking the sheet material 1, and a stacking member 15 for stacking the sheet material 1 and side guide members 16 for guiding both sides of the sheet material 1 so that the sheet material 1 is smoothly fed in the feeding direction. The spring 17 is configured to press the stacked sheet materials 1 against the peripheral surface of the sheet feeding roller 11.

Reference numeral 20 denotes a separation pad supported inside the apparatus main body (not shown) so as to be swingable in the direction of arrow A.
The sheet material 1 pressed by the sheet feeding roller 11 side by the sheet feeding device 14 is brought into contact with the peripheral surface of the sheet feeding roller 11. Reference numeral 22 is a rod-shaped member having a rotation center portion 22a at one end, and the other end 22b is interposed between the paper feed roller 11 and the sheet material 1.

Reference numeral 23 is a pressure releasing cam fixed to both sides of the cam shaft 24 and driven to rotate integrally with the cam shaft 24, and the cam contact portions 18 formed at both ends of the stacking member 15.
Is in contact with. When the pressing release cam 23 rotates and the cam contact portion 18 is pushed downward, the stacking member 15 moves the spring 1
The sheet material 1 stacked on the stacking member 15 by being pushed down against the spring force of 7 separates from the peripheral surface of the paper feed roller 11 (see FIG. 2). In addition, as shown in FIG.
When 3 further rotates to release the pressed state against the cam contact portion 18, the stacking member 15 is repulsed by the spring 17 and moves up, and the sheet material 1 is pressed against the peripheral surface of the paper feed roller 11. 25
Is a contact release cam fixed to the central portion of the cam shaft 24 and rotationally driven integrally therewith, and is arranged near the rotation center portion 22 a of the rod member 22. 3, 4, and 5
In the state where the contact release cam 25 is not in contact with the rod-shaped member 22 as shown in FIG. 5, the other end 22b is in the raised position and the separation pad 20 is in contact with the peripheral surface of the paper feed roller 11. 2, the contact release cam 25 is D
When the rod-shaped member 22 is rotated in the counterclockwise direction, the other end 22b pushes down the separation pad 20 and separates the separation pad 20 from the peripheral surface of the paper feed roller 11.

In FIG. 1, reference numeral 26 is a one-rotation clutch integrally arranged at the end of the cam shaft 24, and 26a is a protrusion thereof, and the other end of the shaft 12 is switched by switching the solenoid 27 on and off. The presence / absence of drive transmission from the drive means 28 provided to the camshaft 24 is switched. 27a
Is the claw. Reference numeral 31 denotes a driven roller rotatably arranged with respect to the shaft 32, which is located on the downstream side of the sheet feeding roller 11 in the sheet material feeding direction.
Is pressed toward the paper feed roller 11 by the paper feed roller 1
The driven rotation is performed together with the rotation of 1. Here, if the frictional forces between the sheet feed roller 11 and the sheet material 1, the separation pad 20 and the sheet material 1, and the sheet materials 1 are T, R, and S, respectively,
The size relationship is T> R <S. In FIG. 2, 34, 35, and 36 are guides for guiding the conveyance of the sheet material 1. Feeding and carrying of the sheet material 1 are performed by making the shape of the pressure release cam 23 and the shape of the contact release cam 25 appropriate shapes described later, and controlling the switching time of the solenoid 27 on / off. be able to.

Next, the operation of the sheet material feeding device will be described. First, the state in which the sheet material 1 is not being fed and conveyed, that is, the standby state for the sheet feed signal shown in FIG. 2 will be described. In this state, the solenoid 27 in FIG.
In the state of ff, the claw portion 27a of the solenoid 27 is caught by the protrusion 26a of the one-turn clutch 26, and the drive from the drive means 28 is not transmitted. Therefore, the driving force transmitted from the other driving roller 13 rotates the sheet feeding roller 11 in the direction of arrow B and the driven roller 31 in the direction of arrow C, but the cam shaft 24 does not rotate.

At this time, the stacking member 15 is pressed toward the paper feed roller 11 side by the spring 17, and the cam contact portions 18 provided at both ends thereof are pressed release cams 23 provided at both ends of the cam shaft 24. Is pushed to move in the direction of arrow F,
The sheet material 1 is kept in a state where it does not contact the paper feed roller 11. In this state, the sheet material 1 is not delivered even if the paper feed roller 11 is constantly rotating. Further, the sheet material 1 can be supplied to the stacking member 15.

On the other hand, the contact release cam 25 is constituted by the rod-shaped member 22.
And the rod-shaped member 22 is moved in the direction of arrow E. Therefore, the other end 22b of the rod-shaped member 22
Is pressed against the separation pad 20 which is urged toward the paper feed roller 11 by the spring 21, and the other end 22b covers the paper feed roller 11. As a result, even if the sheet material 1 stacked on the stacking member 15 is lifted up, the sheet material 1 will not be removed.
Since it contacts the other end 22b of No. 2, it does not contact the paper feed roller 11. That is, even if the sheet material 1 floats up, the sheet material 1 is not delivered.

Next, the paper feeding operation will be described. When a paper feed signal is sent from a control unit (not shown), the solenoid 27 of FIG. 1 attracts the claw portion 27a, the one-rotation clutch 26 is opened, and the drive of the drive means 28 is transmitted to the cam shaft 24. Then, the cam shaft 24 rotates, and at the same time, the pressure release cam 2
3 and the contact release cam 25 rotate. With these rotations, the loading member 15 first moves upward in the direction opposite to the arrow F in FIG. 2, and then the rod-shaped member 22 moves upward in the direction opposite to the arrow E, and the state shown in FIG. 3 is obtained. In this state, the paper feed roller 11 is in pressure contact with both the separation pad 20 and the sheet material 1.
By rotating the paper feed roller 11 in this state, the sheet material 1 on the stacking member 15 is fed between the paper feed roller 11 and the separation pad 20, but the sheet material 1 stacked on the stacking member 15 is Only the uppermost sheet material 1 is sent out due to the difference in frictional force between the separation pad 20 and the paper feed roller 11. FIG. 4 shows this state. What is important here is the order in which the pressure release cam 23 and the contact release cam 25 operate. According to the order described above, the sheet member 1 can be brought into contact with the sheet feeding roller 11 after the shock of the stacking member 15 rising from the lowermost position is absorbed by the rod-shaped member 22, and the double feeding caused by the shock is performed. And misfeed can be avoided. If the order is reversed, the stacking member 15 directly receives the shock of rising from the lowermost position by the sheet feeding roller 11, so that double feeding and misfeeding are likely to occur.

By further rotating the cam shaft 24, the pressing release cam 23 and the contact releasing cam 25 also rotate,
The state shown in FIG. 5 is obtained. However, the shapes of the press release cam 23 and the contact release cam 25 are the same as the rod-shaped member 22 and the stacking member 15.
4 has a shape that does not move from the state of FIG. 4, only the uppermost sheet material 1 sent out in FIG. 4 is conveyed to the position of the driven roller 31.

Further, the cam shaft 24 rotates, and the pressing release cam 23 and the contact releasing cam 25 also rotate.
The shapes of 3 and the contact release cam 25 are such that the rod-shaped member 22 moves in the arrow E direction and the stacking member 15 moves in the arrow F direction. Also at this time, 1
The protrusion 26a of the rotary clutch 26 is caught by the claw 27a of the solenoid 27, and the drive transmission from the drive means 28 is cut off. At this time, the paper feed roller 11 and the separation pad 2
0, the contact between the paper feed roller 11 and the second sheet material 1 stacked on the stacking member 15 is eliminated, and the second sheet material 1 and thereafter are not fed, but the first sheet material The sheet 1 is nipped between the sheet feeding roller 11 and the driven roller 31, and is conveyed to an image forming unit (not shown). At this time, the sheet material 1 is pressed against the rod-shaped member 22 by the separation pad 20, but since the rod-shaped member 22 is made of a low friction material, it does not affect the conveyance of the sheet material 1. After the sheet material 1 has been conveyed, the sheet feeding signal is returned to the state of FIG.

As described above, according to this embodiment, the rotation control of the cam shaft 24 by the on / off of the solenoid 27,
By appropriately setting the shape of the pressure release cam 23 fixed integrally with the cam shaft 24 and the shape of the contact release cam 25, the sheet material 1 is fed and conveyed to the image forming means. For paper and conveyance, a paper feed roller 11 and a driven roller 31
You can do it alone.

Further, in this method, only the rotation control of the cam shaft 24 is performed through the one-rotation clutch 26, so that the driving force required to convey the sheet material 1 by the paper feed roller 11 is transmitted through the one-rotation clutch 26. No need. Further, since the cam shaft 24 also moves the rod-shaped member 22 formed of a low friction material by the contact release cam 25, the rotating portion is small. Therefore, there is no need to use the large-sized one-rotation clutch 26 that has a large drive transmission force and is costly as in the prior art, and the cost can be reduced and the reliability can be improved.

[0024]

As described above, according to the present invention, it is possible to reliably feed and convey the sheet materials one by one with a simple structure having a small number of parts and a light torque transmission force. Further, it is not necessary to use a large-sized one-rotation clutch having a large drive transmission force and a high cost as in the prior art, so that further cost reduction and reliability improvement can be achieved. Further, by constructing the sheet material releasing means, the rotation center portion, and the other end by a rod-like member which can contact the contact portion between the sheet feeding roller and the sheet material, the assembling property of the apparatus can be improved.

[Brief description of drawings]

FIG. 1 is a perspective view of a main part of a sheet material feeding device according to an embodiment of the present invention.

FIG. 2 is a sectional view of an essential part showing a sheet feeding operation of a sheet material feeding device according to an embodiment of the present invention.

FIG. 3 is a cross-sectional view of essential parts showing a sheet feeding operation of a sheet material feeding device according to an embodiment of the present invention.

FIG. 4 is a cross-sectional view of essential parts showing a sheet feeding operation of a sheet material feeding device according to an embodiment of the present invention.

FIG. 5 is a cross-sectional view of an essential part showing a sheet feeding operation of a sheet material feeding device according to an embodiment of the present invention.

FIG. 6 is a cross-sectional view of essential parts showing a sheet feeding operation of a sheet material feeding device according to an embodiment of the present invention.

FIG. 7 is a cross-sectional view of essential parts showing a paper feeding operation of a conventional sheet material feeding device.

FIG. 8 is a cross-sectional view of essential parts showing a paper feeding operation of a conventional sheet material feeding device.

FIG. 9 is a cross-sectional view of essential parts showing a paper feeding operation of a conventional sheet material feeding device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 sheet material 11 paper feed roller 13 drive roller 14 loading means 15 loading member 17 spring 20 separation pad 22 rod-shaped member 22a rotation center part 22b other end 23 pressing release cam 25 contact release cam 28 drive means 31 driven roller

Claims (4)

[Claims] 1. A paper feed roller for feeding a sheet material, a drive means for rotating the paper feed roller, and a sheet material stacking means for pressing the stacked sheet material against the peripheral surface of the paper feed roller. A separation pad for bringing the sheet material sent out from the stacking means into contact with the peripheral surface of the paper feed roller by the rotation of the paper feed roller, and a pressure capable of releasing the pressing of the stacking means on the paper feed roller side. A sheet material feeding device comprising: a release means and a contact release means capable of releasing the contact of the sheet material sent from the stacking means with the paper feed roller. 2. The pressing release means is operated to press the stacking means toward the paper feed roller, and then the contact release means is controlled to bring the sheet material into contact with the paper feed roller. The sheet material feeding device according to claim 1, wherein: 3. The pressing release means comprises a cam for pushing down the stacking means, and the contact release means includes a rod-shaped member having one end interposed between the paper feed roller and the separation pad, and the rod-shaped member. 2. The sheet material feeding device according to claim 1, further comprising a cam that abuts on the member and rotates the rod-shaped member around the rotation center of the other end. 4. A driven roller is provided on the downstream side of the sheet feeding roller in the sheet material feeding direction, the driven roller being pressed by the sheet feeding roller and rotating with the rotation of the sheet feeding roller. The sheet material feeding device according to claim 1.