JP3108161B2 - Sheet transport device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet conveying device applied to an image forming apparatus such as a copying machine, a printing machine, a laser beam printer, etc., and more particularly, to a U-shape for guiding a fed sheet. The present invention relates to a sheet conveying device having a reversing path.

[0002]

2. Description of the Related Art Conventionally, there has been known a sheet conveying apparatus which reverses and conveys a sheet stored in a cassette as a sheet stacking section by a U-shaped reversing path immediately after feeding a sheet by a sheet feed roller. FIG. 1 shows an example of this type of transfer device.
It is shown in FIG.

In FIG. 1, a paper feeding unit 202 disposed below an image forming apparatus 201 includes a paper feeding unit (hereinafter, referred to as a feeding roller) 205 composed of half-moon-shaped rollers and a stacking unit (hereinafter, referred to as a cassette). ) 206 and the like. The cassette 206 includes a middle plate 207 on which the sheets P are stacked, a pressure spring 209 for urging the middle plate 207 toward the feeding roller 205, a separation claw 210 for separating the sheets P one by one, and the like. ing.

[0004] A sheet transport section 211 for transporting the fed sheet P is provided downstream of the paper feed section 202. The sheet conveying unit 211 is provided with a U-shaped inversion path 2
12, a transport roller pair 213, a transport guide 215, and the like. Downstream of the conveyance guide 215, a pair of registration rollers 216 and a photosensitive drum 217 on which a toner image corresponding to image information is formed are provided.

The U-shaped reversing path 212 includes an inner guide 212a and an outer lower guide 212 facing the inner guide 212a.
b, the outer upper guide 212c and the like. The outer lower guide 212b is rotatable about a support shaft 219 to facilitate removal of the jammed sheet P in the U-shaped reversing path 212.

In the image forming apparatus 201, when a start key (not shown) is operated, the sheet feeding roller 205 rotates in the direction of the arrow to feed out the sheet P, and the separation claw 210
, Only the uppermost sheet P is separated and fed to the U-shaped reverse path 212. Further, the sheet P conveyed by the conveying roller pair 213 is conveyed to the photosensitive drum 217 by the registration roller pair 216 at a timing synchronized with the image on the photosensitive drum 217 to form an image. Cassette 2
When the rear end Pb of the fed sheet Pa leaves the separation claw 210, the sheet P in the U-shaped inversion path 212 contacts the outer lower guide 212 b due to the elasticity of the sheet P in the U-shaped inversion path 212. Go on.

[0007]

However, the above-mentioned conventional sheet conveying apparatus has the following problems.

The sheet Pa fed from the cassette 206
Is conveyed in the U-shaped reversing path 212, the sheet Pa
The rear end Pb is located on the outer lower guide 21 of the U-shaped reversing path 212.
Due to hit 2b, a rather unpleasant sound is generated. If the height of the front end of the cassette 206 from which the rear end Pb of the sheet Pa protrudes is not set at a high position so as to form a gap with the outer lower guide 212b of the U-shaped inversion path 212, the sheet front end will be U-shaped inversion path 212 Before it reaches the entrance of the U-shaped reversing path 212, and therefore, the leading end of the cassette 206 and the outer lower guide 212
It was difficult to eliminate the gap with b and the generation of an unpleasant tapping sound.

If the rear end Pb of the sheet Pa is hit so strongly that the rear end Pb rebounds in synchronism with the image formation, the image may be disturbed.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a sheet conveying apparatus in which a rear end of a sheet fed from a stacking section can be conveyed into a U-shaped reversing path without hitting the U-shaped reversing path. It is assumed that.

[0011]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has a cassette for storing sheets and detachable from an apparatus main body, and a cassette for storing sheets contained in the cassette. A sheet feeding means for sequentially feeding the sheet in a direction intersecting with the attaching / detaching direction, and a U-shaped inversion which is adjacent to the downstream side of the cassette in the sheet feeding direction and inverts and guides the sheet fed by the sheet feeding means. A sheet feeding device having a guide position provided in the apparatus main body, a part of which overlaps the cassette and guides a sheet fed from the cassette to the U-shaped inversion path; and A guide member movably provided between a retracted position and a retracted position when the cassette is not mounted, and interlocked with the mounting of the cassette. Characterized in that and a mechanism for moving the guide member to the guide position and release the restriction at the retracted position of the guide member Te.

[0012]

According to the above construction, in a sheet conveying apparatus of a type for feeding sheets in a direction intersecting with the cassette mounting / dismounting direction, a guide member provided on the apparatus main body side is located at a retracted position when the cassette is not mounted. Therefore, the cassette can be mounted smoothly. In addition, since the guide member moves to the guide position in conjunction with the mounting of the cassette, the sheet fed out of the cassette has a rear end portion of the sheet passing through the U-shaped reverse path by the guide member between the cassette and the U-shaped reverse path. It is guided and transported to the U-shaped reversing path without hitting.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, reference embodiments for understanding the present invention will be described first, followed by embodiments of the present invention.

FIGS. 1 and 2 show a reference embodiment.
In FIG. 1, a sheet feeding unit 2 provided at a lower portion in the sheet conveying device 1 includes a sheet feeding unit (hereinafter, referred to as a feeding roller) 5 including a half-moon-shaped roller and a stacking unit (hereinafter, referred to as a cassette).
6 etc. The cassette 6 includes a middle plate 7 on which sheets P are stacked, a pressure spring 9 for urging the sheets P on the middle plate 7 against the feed roller 5, and a separation unit for separating the sheets P one by one. It has claws 10 and the like.

A projection 6a is integrally formed at the tip of the cassette 6, and the projection 6a is arranged at a position where it does not hinder sheet conveyance.

Downstream of the paper feed section 2, there is provided a sheet transport section 11 for transporting the fed sheet P. The sheet transport section 11 includes a U-shaped reversing path 12,
It comprises a pair of transport rollers 13, a transport guide 15, and the like. On the downstream side of the transport guide 15, a registration roller 16 is provided.
And a photosensitive drum 17 on which a toner image corresponding to image information is formed.

The U-shaped reversing path 12 is used for the inner guide 1.
2a and an outer lower guide 12b and an outer upper guide 12c opposed thereto. The outer lower guide 12b is rotatable about a support shaft 19 in order to facilitate removal of the jammed sheet P in the U-shaped reversing path 12.

Outer lower guide 12b of U-shaped reversing path 12
, A base of a two-armed guide member 20 is pivotally mounted on a support shaft 21. When the cassette 6 is inserted into the apparatus main body 3, the protrusion 6a is
The sheet P can be moved to a position (guide position) where the sheet P is passed over the U-shaped reversing path 12 by engaging with the lower arm 20b and rotating clockwise.

The upper arm 20a of the guide member 20 in this state
Is located slightly lower than the exit height of the sheet P fed from the cassette 6 (the height at which the separation claw 10 is located), but a space (gap) between the cassette 6 and the U-shaped reversing path 12. It is located where to grow.

When the cassette 6 is removed from the apparatus main body 3 as shown in FIG. 2, the guide member 20 rotates counterclockwise by its own weight and retracts to a position where it is engaged with the support shaft 19. Although the guide member 20 and the protrusion 6a of the cassette 6 overlap, there is no problem such that they interfere with each other when the cassette is inserted, so that the gap between the cassette 6 and the U-shaped reversing path 12 is filled and the jam sheet is formed. There is no problem with the jam removal property for removing the stencil, the operation of inserting the cassette 6, and the like.

When the sheet conveying device according to the present embodiment is used, the sheet P sent out by the feed roller 5 is
Separated by the separation claw 10 and fed from the cassette 6,
The paper is conveyed to the guide member 20 along the guide member 20. Further, the sheet P is sent to the photosensitive drum 17 by the registration roller 16 at a predetermined timing to form an image.

At the time of feeding the sheet P, the sheet P separates from the separation claw 10 of the cassette 6 and then passes over the guide member 20 with almost no gap and moves toward the U-shaped reversing path 12. can do. Fed sheet P1
When the sheet P1 is conveyed while being nipped by the conveying roller pair 13 as shown in FIG. 1, the rear end of the sheet P1 smoothly guides to the U-shaped reversing path 12 without hitting the outer lower guide 12b. Therefore, the occurrence of a tapping sound at the rear end of the outer lower guide 12b and the disturbance of the conveyance of the sheet P1 as in the conventional apparatus are eliminated.

Next, an embodiment of the present invention will be described with reference to FIGS.
It will be explained by. It is assumed that parts of the sheet conveying apparatus of the present embodiment that are not particularly described have the same configuration as the above-described reference embodiment.

As shown in FIG. 3, the cassette 6 is a so-called front loading type cassette in which the insertion of the cassette 6 into the sheet conveying device is operated from the near side of the operator. Must be inserted in the direction. In this cassette 6, the cassette 6
A protrusion 29 is provided at a rear portion on the front end side of the. The guide member 30 is pivotally supported by the support shaft 21 toward the apparatus main body 3, and has a guide position at which a gap between the cassette 6 and the U-shaped inversion path 12 can be filled, and a guide position of the cassette 6 to the apparatus main body 3. It can be moved between a retracted position for facilitating insertion. FIG. 5 shows a retracted state of the guide member 30 when the cassette 6 is not inserted into the apparatus main body 3, and is lifted by an operation member 31 described later. FIG. 6 shows a state in which the cassette 6 is inserted. The guide member 30 is shown in a guide state in which the guide member 30 has been lowered to a position where the gap between the cassette 6 and the U-shaped reversing path 12 is filled.

As shown in FIGS. 7 and 10, the operating member 31 is pivotally supported by a support shaft 32, and is biased by a resilient force of a tension spring 33 in a direction in which a free end rises. Are located below the guide member 30. When the cassette 6 is not inserted as shown in FIG. 8, the guide member 30 is pushed upward by the operating member 31 and is regulated at the retracted position so that the cassette 6 can be easily inserted. Then, when the cassette 6 is inserted into the apparatus main body 3 as shown in FIG. 7, the projection 29 of the cassette 6 presses the operating member 31 to rotate the free end in a downward direction. Moves to a guide position overlapping the cassette 6 and the U-shaped reversing path 12 so as to fill the gap.

With the above configuration, even in the front loading type cassette, the guide member 30 can fill the gap between the cassette 6 and the U-shaped reversing path 12 without obstructing the insertion of the cassette 6, The guide member 30 can be retracted to a position where the guide member 30 is not obstructed even when the jam of the loading type cassette is cleared.

The protrusion 29 for driving the operating member 31
Can be made movable by operating a handle as shown in FIG. The projection 29 is mounted on the cassette 6 so as to be movable in the left-right direction in the figure, and the front end thereof is pivotally attached to the handle 35. The handle 35 whose base is pivotally supported by the support shaft 35a is urged in the counterclockwise direction in the figure by a tension spring 36. When the cassette 6 is moved to the arrow A and inserted into the apparatus main body 3, the protrusion 29 The operating member 31 is rotated. With the cassette 6 inserted, the protrusion 29 interlocking with the handle 35 is withdrawn so that the guide member 3 can be pulled out without having to pull out the cassette 6.
0 can escape upward, and there is an advantage that the insertion of the cassette 6 into the apparatus main body 3 can be performed more smoothly.

[0028]

As described above, according to the present invention, in a sheet conveying apparatus of a type for feeding sheets in a direction intersecting with a mounting / detaching direction of a cassette, a guide member provided on a main body side of the apparatus has a guide member. When the cassette is not mounted, it is located at the retracted position, so that the cassette can be mounted smoothly.

Since the guide member moves to the guide position when the cassette is mounted, the sheet fed from the cassette is guided and conveyed to the U-shaped reverse path by the guide member between the cassette and the U-shaped reverse path. This allows
The rear end of the sheet is smoothly conveyed into the U-shaped reversing path without hitting the U-shaped reversing path, and the tapping sound due to the sheet rear end generated in the conventional device is eliminated.
The occurrence of image disturbance due to a shock at the time of hitting the rear end is prevented. Further, sheet feeding from the cassette to the U-shaped reversing path becomes smooth.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional side view of a sheet conveying apparatus according to a reference embodiment.

FIG. 2 is an operation diagram.

FIG. 3 is a side view of an apparatus main body and a tray according to the embodiment of the present invention.

FIG. 4 is a side view of the same.

FIG. 5 is a side view of the cassette and the operating member when the cassette is not mounted.

FIG. 6 is a side view of the cassette and the operating member when the cassette is mounted.

FIG. 7 is an operation diagram of an operation member when a cassette is inserted.

FIG. 8 is an operation diagram of the operation member when the cassette is pulled out.

FIG. 9 is a side view showing a modified example of the projection that engages with the operating member.

FIG. 10 is a perspective view of a cassette, a guide member, and an operation member.

FIG. 11 is a side view showing an example of a conventional sheet conveying device.

[Explanation of symbols]

 P sheet 1 sheet conveying device 2 sheet feeding unit 3 apparatus main body 5 sheet feeding means (feeding roller) 6 stacking unit (cassette) 12 U-shaped reversing path 12b lower outer guide 29 protrusion 30 guide member 31 operating member 40 guide member 42 Actuating member

──────────────────────────────────────────────────続 き Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B65H 5/38 B65H 3/68 B65H 15/00

Claims (2)

(57) [Claims] 1. A cassette that stores sheets and is detachable from an apparatus main body, a sheet feeding unit that sequentially feeds the sheets stored in the cassette in a direction that intersects a direction in which the cassette is mounted and demounted, and the cassette. U which is adjacent to the downstream side of the sheet feeding direction and guides the sheet fed by the sheet feeding means in reverse.
And a guide position provided on the apparatus main body, a part of which overlaps the cassette and guides a sheet fed from the cassette to the U-shaped reverse path. A guide member movably provided between a retracted position retracted from the cassette, and a guide member that restricts the guide member at the retracted position when the cassette is not mounted, and interlocks with the mounting of the cassette. And a mechanism for releasing the regulation at the retracted position of the guide member and moving the guide member to the guide position. 2. The apparatus according to claim 2, wherein the guide member is pivotally supported by the apparatus main body so as to be movable between the guide position and the retracted position.
An operating member that pushes up the guide member from the guide position to the retracted position by an elastic force of a spring is provided, and the operating member is rotated by the cassette mounted on the apparatus main body against the elastic force of the spring. 2. The guide member is moved down to the guide position by pressing.
3. The sheet conveying device according to 1.