JPH0721455Y2 - Paper feeder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention relates to a sheet feeding device that separates sheets into an image forming apparatus such as a copying machine, a printer, or a facsimile, and carries the sheets into the apparatus.

[Conventional technology]

For example, in a copying machine, a sheet stored in a sheet tray is carried into the apparatus by a sheet feeding device, and an image is formed on the sheet by a known electrophotographic method. When the paper is fed by the paper feeding device, various sorting methods are adopted so that a plurality of sheets are not simultaneously carried into the device, that is, double feeding does not occur.

As this handling method, corrugation retard method,
The corner snubber method, friction retard method, air feeding method, etc. are known, but because of their simple structure and good paper feeding characteristics as long as they are used under normal conditions, The corner snubber method that uses the paper picking claw is often adopted.

This paper handling claw is necessary to prevent double feeding, but it interferes when paper is replenished in the paper feed tray.
Therefore, when replenishing paper, the user lifts the paper separating claw while pushing down the push-up plate that is tiltably provided in the paper feed tray, and further tilts the bundle of paper in the paper feed tray. It was necessary to carry out the operation of accommodating at the same time. However, it is not easy to perform the above-mentioned plurality of operations at the same time, and there is a problem that workability is poor.

Therefore, in order to improve the workability at the time of replenishing the paper, there is one in which the push-up plate is temporarily fixed to the bottom when the paper is stored. In this type of sheet feeding device, a push-up plate made of a magnetic material is provided so as to be tiltable with respect to the tray, and the push-up plate is biased upward by a spring. Further, a magnet is provided at the bottom of the tray, and first, the push-up plate is pushed down against the force of the spring to be attracted to the magnet and held in the lowered position. At this time, if a stopper is provided so that the paper separating pawl does not fall below a certain height, a space is formed between the push-up plate and the paper separating pawl so that the paper can be easily stored. Then, by mounting the tray in the copying machine, the push-up plate is pushed up by the projecting member provided on the copying machine body side, the attraction by the magnet is released, and the spring force urges the tray upward. Therefore, while the push-up plate moves up with a stack of sheets stacked, the leading edge of the paper is locked by the paper-picking claws and ascends to the lift-up position of the push-up plate and stops. As a result, the leading edge of the sheet is locked by the sheet separating claw, and the bundle of sheets is pressed against the sheet feeding roll (not shown), so that the sheet separating operation can be performed.

[Problems to be solved by the device]

However, as mentioned above, while the push-up plate is rising,
When the paper separating pawl is locked to the paper, the paper is pressed by the paper separating pawl before the posture of the paper is stabilized, so that the engagement state between the paper and the paper separating pawl becomes inaccurate.
If paper feed is started with the paper feed roll in this state, the paper separating operation becomes unstable, and double feeding or paper jam occurs.

Therefore, according to the present invention, it is possible to accurately position the sheet separating claw with respect to the sheet by locking the sheet separating claw on the sheet after the state of the sheet is stabilized, and prevent double feeding and paper jam at the time of sheet feeding. To aim.

[Means for Solving the Problems]

In order to achieve the above-mentioned object, the paper feeding device of the present invention includes a paper feed tray provided so as to be drawn out from the main body of the image forming apparatus, and a push-up plate for placing the paper when the paper feed tray is in the drawn state. Is provided with a locking member that can be locked at the lowered position and that is unlocked when the paper feed tray is stored, and when the paper feed tray is in the pulled-out state, pushes the paper separating claw up to the raised position. In addition, it is characterized in that a push-up member for releasing the pushed-up state when the paper feed tray is stored is released later than the release of the lock of the paper feed tray.

It is preferable that the locking member is provided at a side portion of the paper feed tray and the push-up member is provided at a rear portion of the paper feed tray.

Further, the locking member is engaged with a front end portion of a rail that is provided in the image forming apparatus main body and slidably supports the paper feeding tray with respect to the image forming apparatus main body when the paper feeding tray is stored. The push-up member is abutted against a member provided at a position facing the push-up member on the back side of the image forming apparatus main body when the feeding tray is completely stored. The push-up state may be biased in the direction to be released.

[Action]

In the paper feeding device of the present invention, when the paper feeding tray is pulled out from the main body of the image forming apparatus, the paper picking claw is maintained at the raised position by the push-up member. Further, when the push-up plate is pushed down by hand, the push-up plate is locked by the locking member and maintained at the lowered position.

Here, when the paper is stored in the paper feed tray and pushed into the main body of the image forming apparatus, for example, at the front end of the rail for guiding the paper feed tray, first, the locking member provided on the side of the paper feed tray. Is urged, and the lock by the push-up plate is released. Therefore, the push-up plate rises together with the paper. When the paper feed tray is pushed further in, for example, a push-up member provided at the rear of the paper feed tray abuts against a frame or the like provided at the back of the image forming apparatus body and is urged to raise the paper picking claw. Is released. Therefore, after the posture of the sheet disturbed during the movement of the push-up plate is sufficiently stabilized, the sheet separating claw engages with the sheet. Therefore, the positional relationship between the sheet separating claw and the sheet becomes accurate.

〔Example〕

Hereinafter, features of the present invention will be specifically described based on embodiments with reference to the drawings.

FIG. 1 is a plan view of a paper feeding device according to an embodiment of the present invention, FIG. 2 is a cross-sectional view of the paper feeding device, FIG. 3 is an enlarged rear view of the main parts of the paper feeding device, and FIG. It is a principal part enlarged plan view of an apparatus.

A paper feed tray 1 in which sheets are housed and mounted in the direction of the arrow A with respect to the main body of the copying machine includes a rectangular bottom plate 2 and four bottom plates 2.
Left side plate 3, right side plate 4, front plate 5 which are vertically raised from the side
And a rear plate 6. On the front side of the front plate 5, a drawer portion 7 is provided continuously to the front plate 5.

Between the front plate 5 and the rear plate 6, there are bearings 8 and 9,
A rotating shaft 11 of the push-up plate 10 is pivotally supported, and the push-up plate 10 is tiltable with respect to the bottom plate 2. Push-up plate 10 and bottom plate 2
A compression spring 2a is provided between and, and the push-up plate 10 is biased upward.

Further, as shown in FIG. 4, along the inner wall of the rear plate 6 of the paper feed tray 1, there is provided a paper separating claw 13 which is tiltable about a shaft 12. The sheet separating claw 13 includes an arm 13a pivotally supported by the shaft 12 and a claw body 13b integrally provided at the tip of the arm 13a. The claw body 13b is housed in the paper feed tray 1. It is designed to be locked at the leading edge of the paper. Also, from the inner wall of the rear plate 6 to the arm 13
A protrusion 6a protruding in the a direction is formed, and a steady rest plate 6b is formed at a position sandwiching the arm 13a with the rear face plate 6, and the position of the claw body 13b is regulated by the protrusion 6a and the steady rest plate 6b. It

A paper guide 14 for restricting the lateral position of the paper is attached to the bottom plate 2 of the paper feed tray 1 at a position corresponding to the size of the paper.

In the vicinity of the position where the arm 13a of the rear plate 6 of the paper feed tray 1 tilts, a snubber as a push-up member that pushes up the paper picking claw 13 when the paper feed tray 1 is pulled out from the main body of the copying machine. A link 15 is rotatably provided.

As shown in FIGS. 5A and 5B, the snubber link 15 has a tubular body 15a integrally formed with an actuator piece 15b, a snubber pushing-up piece 15c and a spring locking piece 15d. The snubber link 15 includes a shaft 16 inserted in the tubular body 15a.
Thus, the pair of bearings 17a and 17b are erected on the outer wall of the rear plate 6 of the paper feed tray 1 so as to support the shaft. Back plate 6
A through hole 18 through which the snubber push-up piece 15c can be inserted is formed in the hole, and, as shown in FIG. 6, between the spring locking piece 15d of the snubber link 15 and the spring locking piece 6c of the rear plate 6. In the free state, the snubber link 15 tilts in the direction shown by the arrow B in FIG.
The posture shown by the broken line is obtained, and the arm 13a of the sheet separating claw 13 is lifted by the snubber pushing-up piece 15c.

A push-up plate locking member 20 for maintaining the push-up plate 10 in the lowered position when the paper feed tray 1 is pulled out from the main body of the copying machine is provided near the inner portion of the right side plate 4 of the paper feed tray 1. It is movably installed. As shown in FIGS. 7 (a), (b), and (c), the push-up plate locking member 20 is provided with a substantially right triangular support plate 20a having a through hole 20b, and its lower surface is provided with a support plate 20a. A contact piece 20c that abuts a front end portion 24a of a rail 24, which will be described later, and a locking piece 20d that maintains the push-up plate 10 in a lowered position.
Also, a spring locking piece 20e is formed. Furthermore, the locking piece 20d
An inclined surface 20f and a flat bottom surface 20g are formed on the.
The push-up plate locking member 20 has a screw 21 (see FIG. 8) inserted into the through hole 20b and is screwed into a part of the right side plate 4 from below, so that the right side plate 4 is centered on a vertical axis. The right plate 4 and the spring locking piece 20e of the push-up plate locking member 20 are rotatable.
A tension spring 23 stretched between the spring locking piece 22 formed on the side and the spring locking piece 22 is urged in the direction of arrow D in FIG. The rotation angle of the push-up plate locking member 20 depends on the support plate.
It is limited by a stopper 20h formed on the upper surface of 20a.

On the other hand, at a position corresponding to the push-up plate locking member 20 of the push-up plate 10,
The locking projection 10a is formed, and in a normal state, a part of the locking piece 20d of the push-up plate locking member 20 and a part of the locking projection 10a overlap each other.

Outside plates 3a and 4a are provided outside the left side plate 3 and the right side plate 4 of the paper feed tray 1, respectively.
As shown in FIGS. 8 and 9, a and 4a are guided by a rail 24 having a substantially U-shaped cross section provided on the copying machine main body side,
It can slide back and forth with respect to the main body of the copying machine. Further, a frame 25 is provided at the back of the paper tray 1 accommodating portion on the copying machine main body side so as to abut the actuator piece 15b of the paper snubber link 15.

Next, the operation of the snubber link 15 and the push-up plate locking member 20 when the paper is stored in the paper feed tray 1 and then mounted again in the copying machine main body will be described.

Now, if there is no paper in the paper feed tray 1, the compression spring
The push-up plate 10 is in the raised position by the urging force of the sheet 2a, and the claw body 13b of the sheet separating claw 13 is in direct contact with the corner of the push-up plate 10. At this time, the snubber link 15 is pulled by the tension spring 19 and rotated in the direction of arrow B as shown in FIG. That is, the snubber push-up piece 15c moves upward, and the arm 1 of the paper separating claw 13 moves.
Lifting 3a. Further, the push-up plate locking member 20 is biased in the direction of the arrow D by the tension spring 23, and the locking piece 20d of the push-up plate locking member 20 and the locking protrusion 10a of the push-up plate 10 overlap each other. Has become. However, the locking protrusion 10a is located above the locking piece 20d.

Next, when the push-up plate 10 is manually pushed down against the force of the compression spring 2a, the locking projection 10a comes into contact with the inclined surface 20f of the locking piece 20d,
The push-up plate locking member 20 is indicated by the arrow E against the force of the tension spring 23.
The locking piece 20d pivots in the direction and retracts with respect to the locking projection 10a. When the push-up plate 10 is pushed further in, the locking projection 10a
After passing through the 0d portion, the push-up plate locking member 20 returns to the original position shown in FIG. 4 by the force of the tension spring 23.

Next, when the hand is released from the push-up plate 10, the push-up plate 10 is pressed by the compression spring 2a
However, at this time, the locking piece 20d is located above the locking projection 10a, and the locking piece 20d
Since the bottom surface 20g of d is flat, the locking projection 10a
The push-up plate 10 is prevented from rising by being locked by. That is, the push-up plate 10 is maintained in the depressed state.

Therefore, when storing paper in the paper feed tray 1,
It is sufficient to simply place a stack of sheets on the push-up plate 10 and the workability is good. At this time, as described above, the paper separating claw 13
Since it is also in the raised position, the claw body 13b does not interfere with the paper accommodating work.

Next, when the paper feed tray 1 is pushed toward the main body of the copying machine, the outer plates 3a and 4a of the paper feed tray 1 are guided by the rails 24 and proceed in the depth direction of the main body of the copying machine. When the push-up plate locking member 20 provided on the paper feed tray 1 reaches the front end portion 24a of the rail 24 (see FIG. 9), the contact piece 20c abuts on the rail 24, and the push-up plate locking member 20 moves. It rotates in the arrow E direction against the force of the spring 23. Therefore, the locking piece 20d retracts with respect to the locking projection 10a, and the push-up plate 10 holds the stack of sheets on the compression spring 2a.
Is moved upward by the force of and contacts the upper limit stopper (not shown) to stop.

When the push-up plate 10 moves upward, the push-up plate is impacted by an impact.
Although the posture of the bundle is temporarily disturbed on the sheets placed on the sheet 10, at this time, since the sheet separating claw 13 is lifted upward by the snubber pushing-up piece 15c, the sheet posture is not restricted, and the sheet is naturally restrained. Return to the correct posture.

Next, when the paper feed tray 1 is fully inserted, as shown in FIG. 6, the actuator piece 15b of the snubber link 15 is pressed by the frame 25 provided on the main body of the copying machine,
It rotates in the direction of the arrow C and assumes the posture shown by the solid line. That is, since the snubber pushing-up piece 15c is in the lowered state, the sheet handling claw 13 is also lowered accordingly, and the claw body 13b stops in a state of contacting the corner of the sheet.

Since there is a time lag between the lifting plate 10 rising and the sheet separating claw 13 lowering, when the claw body 13b abuts the sheet, the posture of the sheet is already stable, and the position of the sheet and the sheet The positional relationship with the separating claw 13 becomes accurate. Therefore, at the time of the paper feeding operation, the uppermost sheet of the bundle of sheets is reliably separated by the sheet separating claw 13 one by one and conveyed, and the risk of double feeding is greatly reduced.

Table 1 compares the state of double feeding in the conventional sheet feeding apparatus that simultaneously raises the push-up plate and lowers the sheet picking claws with the state of double feeding in the sheet feeding apparatus according to this embodiment.

As is clear from the above table, according to the present embodiment, it is possible to greatly reduce the occurrence of double feeding especially at the interface which is the boundary of the sheet bundle.

[Effect of device]

As described above, according to the present invention, since the paper separating claw is locked to the paper after the posture of the paper is stable, the positional relationship between the paper separating claw and the paper is accurate. Become. Therefore, at the time of the paper feeding operation, the uppermost sheets of the bundle of sheets are reliably separated one by one and conveyed, and the possibility of double feeding is greatly reduced.

Further, a locking member for locking the push-up plate is provided on a side portion of the paper tray, and a push-up member for pushing up the paper picking claw is provided on the rear portion of the paper feed tray, thereby interlocking with the mounting operation of the paper feed tray. , The locking of each part is automatically released with a time lag.

[Brief description of drawings]

FIG. 1 is a plan view of a paper feeding device according to an embodiment of the present invention, FIG. 2 is a cross-sectional view of the paper feeding device, FIG. 3 is an enlarged rear view of the main parts of the paper feeding device, and FIG. FIG. 5 (a) and FIG. 5 (b) are side views and a plan view of a single snubber link, and FIG. 6 is a diagram for explaining the operation of the snubber link. ), (B) and (c) are a plan view, a front view and a side view of the push-up plate locking member alone, FIG. 8 is a schematic sectional view showing a sliding structure of the paper feed tray, and FIG. 9 is a push-up plate engaging member. It is a schematic perspective view which shows the relationship between a stop member and a rail. 1: Paper tray, 2: Bottom plate 2a: Compression spring, 3: Left side plate 3a, 4a: Outer side plate, 4: Right side plate 5: Front plate, 6: Rear plate 6a: Protrusion, 6b: Rest plate 6c: Spring Locking piece, 7: Drawer 8, 9: Bearing, 10: Push-up plate 10a: Locking protrusion, 11: Rotating shaft 12: Shaft, 13: Paper picking claw 13a: Arm, 13b: Claw body 14: Paper guide, 15: Snubber link 15a: Cylindrical body, 15b: Actuator piece 15c: Snubber push-up piece, 15d: Spring locking piece 16: Shaft, 17a, 17b: Bearing part 18: Through hole, 19: Extension spring 20: Push-up plate locking member, 20b: through hole 20a: support plate, 20c: contact piece 20d: locking piece, 20e: spring locking piece 20f: inclined surface, 20g: bottom surface 20h: stopper, 21: screw 21 22: Spring locking piece, 23: Extension spring 24: Rail, 24a: Front end 25: Frame

Claims (3)

[Scope of utility model registration request] 1. A paper feed tray provided so as to be drawn out from the main body of the image forming apparatus, a push-up plate for placing paper can be locked at a lowered position when the paper feed tray is in a drawn-out state, and Providing a locking member for releasing this locking when the paper feed tray is stored, pushing up the paper separating claw to a raised position when the paper feed tray is in a pulled-out state, and pushing up when the paper feed tray is stored A sheet feeding device provided with a push-up member for releasing the state after the release of the lock of the sheet feeding tray. 2. The paper feeding apparatus according to claim 1, wherein the locking member is provided on a side portion of the paper feeding tray, and the push-up member is provided on a rear portion of the paper feeding tray. 3. The locking member contacts a front end portion of a rail which is provided in the image forming apparatus main body and slidably supports the paper feeding tray with respect to the image forming apparatus main body when the paper feeding tray is stored. The push-up member is provided in a position facing the push-up member on the back side of the main body of the image forming apparatus when the feeding tray is completely stored. 3. The sheet feeding device according to claim 2, wherein the sheet feeding device is urged in a direction in which the member is brought into contact with the member and the lifted state is released.