JPH06263273A - Paper feeder - Google Patents

Abstract

PURPOSE:To downsize a driving force transmitting switching mechanism to separate and carry a paper sheet as well as to improve reliability. CONSTITUTION:A driving force transmitting switching mechanism 2 has a sun gear 19, a planetary arm 17, a planetary gear 21, a planetary gear support shaft 23 and a push-pressing spring 27, and has a fixed disk shape cam mechanism 26 which receives push-pressing force of the push-pressing spring 27 through the planetary gear 21 and allows autorotation and revolution of the planetary gear 21. The fixed disk shape cam mechanism 26 has a gear pushing-up cam surface 24A on a revolution orbit of the planetary gear 21 so as to push up the planetary gear 21 in the direction for separating from above the disk shape cam mechanism 26 against the push-pressing force of the push-pressing spring 27, and a meshing place to mesh so as to be engaged with/disengaged from a gear where the planetary gear 21 is connected to a paper sheet separating roller 1A, is arranged in a prescribed position on the revolution orbit in the regular direction of the planetary gear 21, and an inverse rotation preventive means 26A is arrange in the fixed disk shape cam mechanism 26 in the meshing place so as to check the revolution in the inverse direction of the planetary gear 21.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet feeding device, and more particularly to a sheet feeding device provided with a sheet separating mechanism portion, a sheet conveying mechanism portion, and a driving force transmission switching mechanism for transmitting a driving force to both of them. Regarding

[0002]

2. Description of the Related Art Conventionally, a sheet feeding device of this type is provided with a driving motor for each of the sheet separating and conveying means, or a driving force transmission switch as shown in FIGS. A device having a mechanism is known (for example, Japanese Patent Application Laid-Open No. 4-148959).

A conventional sheet feeding device having a driving force transmission switching mechanism will be described below. Here, FIG. 13 is a longitudinal sectional view of a main part including a driving force transmission switching mechanism of a conventional sheet feeding device, FIG. 14 is an exploded perspective view of the driving force transmission switching mechanism, and FIGS. It is a figure for demonstrating operation | movement of a switching transmission mechanism.

In FIGS. 13 and 14, the rotational drive force of the platen gear 110 is transmitted to the drive force transmission switching mechanism 103 via the drive transmission system 102.
The driving force transmission switching mechanism 103 is a driving disk 104.
And a control disk 105 and an idle gear 106 arranged on the same axis as the entrainment disk 104. The idle gear 106 meshes with the idle gear 107 of the next stage.
Is meshed with an idle gear 108 provided on a rotating shaft 109A of a sheet separating roller 109 for feeding a sheet (not shown) to the platen 110.

As shown in FIG. 14, the entrainment disc 104 is provided with a fan-shaped notch 141, and the engaging lever pin 11 protruding into the notch 141.
An engagement lever 111 having 1A is provided. One end of the engagement lever 111 is swingably supported and is biased via a spring 112 so as to face the center of the disc. Further, a stopper 113 is provided on the surface of the entrainment disc 104 that matches the control disc 105.

The control disk 105 has a circular outer peripheral edge 15
1 is provided, and a guide lever 114 formed of a leaf spring for providing a part of the death process is provided. A plate spring-shaped stopper 115 is provided on the surface of the control disk 105 that matches the entrainment disk 104, and is raised so that the drive rotation direction is the forward rotation side (clockwise direction). Further, a guide pin 116, which can be brought into contact with the idle gear 106, is provided in the dead process portion of the circular outer peripheral edge 152 in a form having a linear cam shape like a spring. On the other hand, the idle gear 106 is provided with a stopper 117 projecting on a surface thereof which coincides with the control disk 105 and which can be engaged with the guide pin 116.

Next, the operation of such a conventional example will be described with reference to FIGS.

First, as an initial state, the platen gear 10
It is assumed that 1 rotates in the normal direction. This rotational force is transmitted via the drive transmission system 102 to the drive disc 104 that constitutes the drive force transmission switching mechanism 103, and then to the control disc 105 via the stopper 113 provided on the drive disc 104. It At that time, carry disk 1
The position of the engaging lever pin 111A provided at 04 is at the starting point on the control disk (see FIG. 15).

Next, the platen gear 101 is instructed by the suction command.
Is reversed for a few lines (counterclockwise), the engaging lever pin 1
11A moves to the top dead center position of the control disk 105 (see FIG. 16).

Further, the platen gear 10 is used for the suction operation.
When 1 is rotated in the normal direction, the engagement lever pin 111A moves to the position of the bottom dead center (see FIG. 17). At that time, the engaging lever pin 111A pushes down the guide pin 116 provided in the dead step (top dead center to bottom dead center) of the control disk 105, and the stopper 11 provided in the idle gear 106.
By linking with 7, the rotational driving force of the platen gear 101 is transmitted to the idle gear 108, and the paper is fed from the paper separating roller 109 to the platen 110.

Next, in order to perform the intermittent operation, as a method of releasing the power, after the sheet is fed to the platen 110, the platen gear 110 is reversed until the engaging lever pin 111A overcomes the dead process, and the control is performed. The guide pin 116 at the bottom dead center of the disk 105 returns, the idle gear 106 becomes idle, and the rotation driving force of the platen 110 thereafter is not transmitted to the paper separating roller 109. Note that the engagement lever pin 111A during reverse rotation
Collides against the guide lever 114, but the guide lever 11
Since 4 is formed as a leaf spring, it can slip over the lever portion as shown in FIG.

In this way, the starting point defined by normal rotation is established with the driving force transmission switching mechanism 103 as the initial state, and the suction command is performed through the reverse rotation operation for several lines, whereby the death process is performed. By moving to the position of top dead center and further moving to the position of bottom dead center by inhaling operation and changing to normal rotation,
The driving force of the platen gear 101 is the sheet separation roller 109.
Be transmitted to. As a releasing method, the driving force is released by applying the reverse rotation again, and the normal rotation further causes the driving force transmission switching mechanism 103 to return to the initial state again, whereby the sheet passes through the platen 110 and is discharged. Become.

[0013]

However, in such a conventional sheet feeding device, there are many constituent elements of the transmission system from the driving source to the sheet separating roller, so that the driving force is lost and the driving force is reduced. Since the transmission switching mechanism is composed of triple discs, it is difficult to downsize the device. In addition, the shape of the portion of the disc itself that has the spring property is naturally thin, and in particular, the adoption of the structure that utilizes the spring property of the entrainment mechanism causes the deformation of the linking part due to the thin wall, which reduces the transmission efficiency. It was happening.

Further, in the paper feeding device of the type in which drive motors are provided for separating paper and for transporting paper, it is difficult to reduce the cost, downsize the device, and reduce the weight of the device.

[0015]

It is an object of the present invention to improve the disadvantages of the conventional example, and particularly to reduce the transmission loss of the driving force by reducing the transmission elements interposed from the predetermined drive source to the sheet separating roller and to reduce the transmission loss. It is an object of the present invention to provide a sheet feeding device capable of driving the sheet separating roller and the platen by the driving source of (3) and simplifying and downsizing the structure.

[0016]

According to the present invention, there is provided a sheet feeding apparatus having a driving force transmission switching mechanism for intermittently driving and controlling a sheet separating roller on a sheet hopper side by using a drive motor for driving a platen. The drive force transmission switching mechanism has a sun gear that rotates forward and backward in conjunction with the rotation of the drive motor, a planetary arm and a planetary gear that engage with the sun gear, and the planetary gear supported by the planetary arm is the axis of the sun gear. And a planetary gear support shaft that guides reciprocating movement in parallel with, and a pressing spring that is provided between the planetary arm and the planetary gear, and receives the pressing force of the pressing spring through the planetary gear, and Equipped with a fixed disc-shaped cam mechanism that allows the planetary gear to rotate and revolve, and this fixed disc-shaped cam mechanism separates the planetary gear from the disc-shaped cam mechanism against the pressing force of the pressing spring. Push up A gear pushing-up protrusion is provided on the revolution orbit of the planetary gear, and the planetary gear engages and disengages with a gear connected to the paper separating roller at a predetermined position on the revolution orbit of the planetary gear in the forward direction. In addition to providing the meshing portion, the fixed disc-shaped cam mechanism at the meshing portion is provided with an inversion preventing means for preventing the planetary gear from revolving in the opposite direction. This aims to achieve the above-mentioned object.

[0017]

In the present invention, the rotation of the motor gear causes the sun gear engaged with the motor gear to rotate, and with this rotation, the planet gear revolves around the sun gear in the forward direction. A fixed disc-shaped cam mechanism or the like provided between the planetary gear and the separation roller gear prevents the planetary gear from revolving in the opposite direction and separates the planetary gear from the separation roller gear during paper separation. At a predetermined timing, for example, when the paper separating operation is completed, the planet gear is allowed to revolve in the positive direction and the engagement between the planet gear and the separating roller gear is released.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS.

The embodiment shown in FIGS. 1 to 9 is provided with a drive force transmission switching mechanism 2 for intermittently controlling the drive of the sheet separating roller 1A on the side of the sheet hopper 1 by using a drive motor 12 for driving the platen. ing. This driving force transmission switching mechanism 2
Is a sun gear 19 that rotates forward and backward in synchronization with the rotation of the drive motor 12, and the planetary arm 1 that engages with the sun gear 19.
7 and the planetary gear 21, a planetary gear support shaft 23 supported by the planetary arm 17 for guiding the planetary gear 21 to reciprocate in parallel to the axis of the sun gear 19, the planetary arm 17 and the planetary gear 21. Pressure spring 27 installed between and
It has and.

Further, the pressing force of the pressing spring 27 is controlled by the planetary gear 2
1 is equipped with a fixed disc-shaped cam mechanism 26 which receives the rotation of the planetary gear 21 and allows the planetary gear 21 to rotate and revolve. The fixed disc-shaped cam mechanism 26 includes a pressing spring 27.
The planetary gear 21 against the disc-shaped cam mechanism 2 against the pressing force of the planetary gear 21.
6 is equipped with a cam surface 24A for pushing up the gear which pushes it up in the direction to separate from the top on the revolution orbit of the planetary gear.

Further, at a predetermined position on the revolution path of the planetary gear 21 in the forward direction, there is provided a meshing portion at which the planetary gear 21 meshes with a separation roller gear 28 connected to the sheet separation roller 1A so as to be freely disengageable. On the fixed disc-shaped cam mechanism 26 at the meshing portion, a reversal prevention unit 26A that prevents the planetary gear 21 from revolving in the opposite direction is provided.

To explain this in more detail, FIG. 1 shows a schematic configuration diagram of a sheet conveying system showing an embodiment of the present invention, and FIG. 2 shows a sectional view of a driving force transmission switching mechanism. 3 to 9 are state diagrams of the driving force transmission system in the switching of the driving force transmission in this embodiment.

The paper transport system, as shown in FIG.
A paper hopper 1 constituting a storage portion of the paper, a paper separating roller 1A for separating the paper P from the paper hopper 1 one by one, and paper transport guides 4A, 4B for directing the paper P sent from the paper hopper 1 to the platen 3. This paper guide 4A, 4
A sheet detection sensor 5 disposed along B and provided for detecting the presence or absence of the sheet P, a rear pressure roller 6 and a front pressure roller 7 that are in contact with the outer peripheral surface of the platen 3, and the sheet P. And a paper discharge roller pair 9 that conveys the printed paper P to the stacker 10.

The driving force transmission system to the platen 3 is, as shown in FIGS. 1 to 4, a single driving motor 12 fixed to a frame 11 via a bracket (not shown).
A motor gear 13 fixed to the output shaft of the drive motor 12, an idle gear 14 rotatably supported via a rotation shaft (not shown) provided in the frame 11, and an idle gear 14 engageable with the idle gear 14. Provided,
The platen gear 15 is fixed to the shaft end portion of the platen 3.

As shown in FIG. 1, the drive force transmission switching mechanism 2 for the sheet separating roller 1A is rotatably supported by the rotary shaft 16 on the frame 11 and engageable with the idle gear 14. A sun gear 19, a planetary arm 17 provided at an end of the sun gear 19 opposite to the frame, and a planetary gear 21 supported by a rotary shaft 23 provided at a tip end of the planetary gear 17 are configured to be included. ing.

More specifically, the base end portion of the planetary arm 17 of the sun gear 19 is provided with a tubular sliding portion 20 which is fitted onto the rotating shaft 16, and the sliding portion 20 is provided.
A friction sheet 18 is interposed between the sun gear 19 and the sun gear 19. The planetary gear 21 supported by the planetary arm 17 is integrally provided with a cam follower portion 22, and the planetary gear 21 is normally provided with a slide spring 27 arranged between the planetary gear 21 and the cam follower 22. Are urged toward the fixed disc-shaped cam mechanism 26 provided on the frame 11. The fixed disc-shaped cam mechanism 26 is formed with two cam surfaces 24A, 24B for shifting the planetary gear 21 in the axial direction at predetermined intervals. When the planetary gear 21 revolves in the forward direction (direction of arrow 30 in FIG. 5), these two cam surfaces 24A and 24B function as a gear pushing-up protrusion, and in the opposite direction (direction of arrow 29 in FIG. 3). When revolving, it functions as a reversal prevention means. Further, as shown in FIG. 4, the separation roller gear 28 is fixedly mounted on the shaft end of the paper separation roller 1A as described above.
The planetary gear 22 can be appropriately engaged with the separation roller gear 28, and when the two are engaged, the paper separation roller 1A
Power is transmitted to.

Next, the operation of this embodiment will be described with reference to FIG.

When the power of the printer main body is turned on, or when the paper feeding device is attached to the printer main body, the planetary gear 21 is initialized so as to be set to the initial position described later. When the sheet suction command is sent, the drive motor 12 rotates in the forward (clockwise) direction by a specific step. Power from the drive motor 12 is idle gear 14, sun gear 1
9 is transmitted to the planet arm 17 via the
3 moves in the direction of the arrow 29 in FIG. 3, the cam follower 22 of the planetary gear 21 hits the wall of the cam surface 24B of the clutch cam 26, and the planetary arm 17 cannot move any further in the direction of the arrow 29, and the planetary gear 21 moves. Clutch cam 2
The idler section 25 of 6 is designed to idle. This state, that is, when the planetary gear 21 is in the idling portion 25 of the clutch cam 26 is the initial state (see S200 in FIG. 10). At this time, the driving force transmission mechanism is in the state shown in FIGS. 3 and 4, and in this state, the sheet separation roller 1A
No drive force is transmitted to the.

After the initialization is completed, the paper detection sensor 5 detects the presence or absence of paper (see S201 in FIG. 10). Here, if the absence of paper is detected, the operation proceeds to the paper separating operation. That is, the drive motor 12 is reversely rotated by a specific step from the above-mentioned initial state (see S202), and the sun gear 1
By reversing 9 the planetary arm 17 is moved in the direction of arrow 30 shown in FIG. At this time, the planet gear 21 revolves around the sun gear 19 in the direction of the arrow 30 and moves along the cam surface 24A while shifting. By this shift operation, the planetary gear 21 rides over the separation roller gear 28 as shown in FIGS. 5 and 6. In this case, torque is transmitted from the sun gear 19 to the planet arm 17 via the friction sheet 18, and the planet gear 21 can easily climb up the cam surface 24A. After that, by rotating the drive motor 12 forward again, the planetary gear 21 revolves somewhat in the clockwise direction in FIG. 7, and the planetary gear 21 and the separation roller gear 28 are as shown in FIGS. 7 and 8. Are engaged with each other. As a result, the driving force can be transmitted to the separation / separation roller 2 and the sheet can be separated or the sheet can be conveyed to the platen 3 (see S203).

When the conveyance of the sheet to the platen 3 is completed, the drive motor 12 is released in order to cancel the drive transmission to the sheet separating roller 1A in order to prevent the sheet P from being continuously sent out from the hopper 1.
Is reversed by a specific step (see S204 in FIG. 10). By this reverse rotation operation, the planetary arm 17 moves in the direction of the arrow 31 as shown in FIG. 9, the planetary gear 21 climbs along the cam surface 24B, and after landing on the idle portion 25.

After that, the drive motor 12 is normally rotated (see FIG. 1).
During 0, refer to S205), paper feed is performed, and printing and paper ejection are performed. At this time, the planetary gear 21 is prevented from moving in the direction of the arrow 29 by the action of the other reversal preventing means (the end surface of the cam surface 24B on the side of the idle portion 25) in the idle portion 25 as described above, and continues to idle. Become. In addition, this idling section 2
Since the state in which the planetary gear 21 is positioned at 5 is the initialized state as described above, the reverse operation is performed when the next print command is sent after the printing is completed, and the above-described operation is repeated.

Here, the initial state will be supplemented. When the planetary gear 21 is in the area A (between the wall of the cam surface 24A and the slope of the cam surface 24B) shown in FIG. 9 due to a disturbance, for example, when the paper feed knob of the printer main body is turned when the power is turned on, When the drive motor 12 is rotated in the normal direction, the drive force is transmitted to the separation roller 1A and the paper is sent, but at this time,
Since the sheet detection sensor 5 detects the sheet suction, the drive motor 12 is once rotated in the reverse direction (see S206 in FIG. 10).
After releasing the drive transmission to the sheet separation roller 2 in this manner, the drive motor 12 is rotated in the normal direction (see S207), and the sucked sheet is once discharged and then rotated in the reverse direction (S208).
After the planetary gear 21 is initialized, the planetary gear 21 may be rotated in the normal direction to perform the sheet suction operation (see S209). On this occasion,
It is desirable to make the area A as narrow as possible in order to remove the influence of disturbance.

By such a series of operations, sheet separation and sheet separation roller 1 are carried out through forward and reverse rotations of drive motor 12.
The driving force transmission to A can be canceled, the paper can be fed, and the paper can be discharged.

Next, another embodiment of the present invention will be described with reference to FIGS.

In this embodiment, while the fan-shaped position detecting section 34 is provided on the planetary arm 17 in the above-described embodiment, the position detecting sensor 33 is provided correspondingly thereto, and the position detecting section 34 and the position detecting sensor 33 are used. The feature is that the initial position detecting means is configured. That is, the planetary arm 17 blocks the slit of the position detection sensor 33 when the planetary gear 21 is in the region A shown in FIG. 9, and whether the planetary gear 21 is in the region A at the start. The position detecting sensor 33 detects the angle (see S300 in FIG. 12). Here, when the planetary gear 21 is located in the area A, the drive motor 12 is rotated in the reverse direction (see S301), and the planetary gear 21 is normally rotated after the planetary gear 21 is disengaged from the area A (see S302), and the planetary gear 21 is returned to the normal initial state. After being moved to the position, the sheet is normally rotated again to connect to the sheet separation gear 28 for the sheet separation operation (see S303).

Next, when the paper is separated, the planet gear 21 must be in the area A. At this time, the position detection sensor 33 determines whether the planet gear 21 is in the area A or not. (See S304). If it is determined that the planet gear 21 does not exist in the area A, the reverse rotation is performed until it is detected that the planet gear 21 exists in the area A (S30).
After this is detected, the sheet is normally rotated and the sheet separating operation is started (see S306).

After the paper separation is completed, the paper separation gear 2
8 is reversed to release the connection to S8 (see S307).
Then, during the paper feeding or discharging operation, the planetary gear 2
Although 1 should not be in the area A, the position detection sensor 33 judges this at this time. Here, when it is determined that the planetary gear 21 exists in the area A, the area A
Is reversed until the planet gear 21 escapes from (S30
9)), when the escape is confirmed, rotate the paper forward and feed it,
The discharge operation is started (see S310).

According to this embodiment, the drive force transmission switching mechanism of the sheet feeding device is the sun gear 19, the planetary arm 17, the planetary gear 21, the fixed disk-shaped cam mechanism 26, and the pressing spring 2.
7 and the like, the drive force transmission switching at the time of sheet separation and sheet conveyance is performed by the forward rotation and the reverse rotation of the drive motor 12. Therefore, it is not necessary to provide drive motors for sheet separation and sheet conveyance, respectively, and thus cost reduction. There is an effect that the size and weight can be reduced.

Further, in the above-described embodiment, the driving force transmission switching mechanism can be downsized by adopting a structure different from the conventional triple disk structure, and further, a portion weak in rigidity as compared with the prior art. In addition, since the number of transmission elements interposed from the drive motor 12 as a drive source to the sheet separation roller 2 is small, it is possible to obtain an effect that the driving force transmission loss is reduced.

Further, the planetary arm 17 is provided with the position detecting section 34 and the position detecting sensor 33 having a slit through which the position detecting section 34 can pass, so that the planetary gear 21 is displaced from the initial position due to disturbance or the like. However, there is an effect that this can be corrected without difficulty and the reliability can be further improved.

[0041]

The present invention is constructed as described above, and
According to this, according to this, since the drive force transmission switching mechanism is configured around the sun gear, the number of transmission elements interposed from the predetermined drive source to the sheet separation roller is reduced, which effectively reduces the transmission loss of the drive force. Can be suppressed,
In addition, since the sheet separating roller and the platen can be driven by a single drive source, it is possible to provide an excellent paper feeding device that has not been available in the related art in which the structure can be simplified and the size can be reduced. .

[Brief description of drawings]

FIG. 1 is a sectional view of a driving force transmission switching mechanism according to the present invention.

FIG. 2 is a schematic configuration diagram showing a paper transport system in which the embodiment shown in FIG. 1 is incorporated.

3 is a state explanatory view showing an initial position of the driving force transmission switching mechanism shown in FIG. 1 before sheet separation.

FIG. 4 is a schematic right side view with a part of FIG. 3 omitted.

FIG. 5 is an explanatory view of a state on the way from the initial position to the connection to the sheet separation gear.

FIG. 6 is a schematic right side view with a part of FIG. 5 omitted.

FIG. 7 is an explanatory view showing a state when the planetary gear and the separation roller gear are engaged with each other.

8 is a schematic right side view with a part of FIG. 7 omitted.

FIG. 9 is a state explanatory view for explaining an operation when the planetary gear is not at the initial position.

FIG. 10 is a flow chart for explaining the overall operation of the above embodiment.

FIG. 11 is a state explanatory view showing a driving force switching mechanism portion in another embodiment of the present invention.

12 is a flow chart for explaining the overall operation in the embodiment shown in FIG.

FIG. 13 is a cross-sectional view in which a main part including a driving force transmission mechanism in a conventional paper feeding device is partially cut longitudinally.

FIG. 14 is an exploded perspective view of a driving force transmission mechanism of a conventional example.

FIG. 15 is a diagram for explaining a relative positional relationship between a drive disk and a control disk of a driving force transmission mechanism of a conventional example.

FIG. 16 is a diagram for explaining a relative positional relationship between a drive disc and a control disc of a driving force transmission mechanism of a conventional example.

FIG. 17 is a diagram for explaining a relative positional relationship between a drive disc and a control disc of a driving force transmission mechanism of a conventional example.

FIG. 18 is a diagram for explaining a relative positional relationship between a drive disk and a control disk of a driving force transmission mechanism of a conventional example.

[Explanation of symbols]

 1 Paper Hopper 1A Paper Separation Roller 2 Drive Force Transmission Switching Mechanism 3 Platen 12 Drive Motor 13 Motor Gear 17 Planetary Arm 19 Sun Gear as a Sun Gear 21 Planetary Gear as a Planetary Gear 24A Fixed Cam Surface 24B on Fixed Disc-shaped Cam Mechanism Cam surface 26 on the disc-shaped cam mechanism 26 Fixed disc-shaped cam mechanism 27 Pressing spring 28 Separation roller gear 33 Position detection sensor constituting initial position detection means 34 Position detection unit constituting initial position detection means

Claims (4)

[Claims] 1. A sheet feeding device provided with a driving force transmission switching mechanism for intermittently driving and controlling a sheet separating roller on a sheet hopper side by using a drive motor for driving a platen, wherein the driving force transmission switching mechanism comprises: A sun gear that rotates forward and reverse in conjunction with the rotation of the drive motor, a planet arm and a planet gear that engage with the sun gear, and the planet gear supported by the planet arm is parallel to the axis of the sun gear. A planetary gear support shaft that guides the reciprocating movement, and a pressing spring provided between the planet arm and the planetary gear, and receives the pressing force of the pressing spring via the planetary gear, The planetary gear is equipped with a fixed disk-shaped cam mechanism that allows the planetary gear to rotate and revolve, and the fixed disk-shaped cam mechanism moves the planetary gear on the disk-shaped cam mechanism against the pressing force of the pressing spring. Leave from A planetary gear revolving orbit is mounted on the revolution orbit of the planetary gear, and the planetary gear is engaged with the gear connected to the paper separating roller at a predetermined position on the revolution orbit of the planetary gear in the positive direction. In addition to providing a meshing point that meshes freely
A sheet feeding device, characterized in that the fixed disc-shaped cam mechanism at the meshing portion is provided with an inversion prevention means for preventing the planetary gear from revolving in the opposite direction. 2. The planetary arm is engaged with the sun gear by a frictional force that is large enough to maintain a revolution force of the planetary gear at an axial center portion of the sun gear. Item 1. The sheet feeding device according to item 1. 3. The paper feeding device according to claim 1, wherein the reversal preventing means is formed integrally with a cam surface for pushing up a gear, which is a part of the disk-shaped cam mechanism. 4. The paper feeding device according to claim 1, wherein the planetary arm includes a position detection sensor that externally outputs a rotational position of the planetary arm.