JPH08188294A - Paper feeding device and image forming device - Google Patents

Abstract

PURPOSE: To maintain operability to supply paper sheets and process jamming by a method wherein when a paper placing table is mounted on a device body, an auxiliary guide member is positioned by an energizing means to apply a given suction force on the paper placing table and when the paper placing table is separated away from the device body, the auxiliary guide member is separated away from the paper placing table. CONSTITUTION: An auxiliary guide member 26 is supported to one end of a U-turn guide member 6 and arranged to the vicinity of the the inversion curved part 16 of a paper cassette 4 being the paper placing table of the U-turn guide member 6. When the paper cassette 4 is mounted on a device body, the auxiliary guide member 26 is engaged with a tension spring 25, being an energizing means to apply a given suction force or a press force on the paper cassette 4, for positioning. Further, when the paper cassette 4 is separated away from the device body, the auxiliary guide member 26 is separated away from the paper cassette 4. This constitution maintains operability to supply paper sheets 2 and process jamming.

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 used in image forming apparatuses such as copying machines, laser beam printers, electrostatic printers and facsimiles.

[0002]

2. Description of the Related Art Conventionally, as a sheet feeding apparatus having a reversing guide member for reversing the sheet feeding direction, for example, there is one as shown in FIG. This sheet feeding device 100
Is provided with a sheet cassette 111 for accommodating the sheet bundle 102, and the sheet bundle 102 is stacked on an intermediate plate 105 provided in the sheet cassette 111.

Further, the intermediate plate 105 is illustrated by a pressure spring 104.
The sheet bundle 102 is urged above the sheet 12, and is pressed against the feeding roller 103. The sheet 101 located at the top of the sheet bundle 102 is separated by the feed roller 103 and the separation claw 112 provided in front of the sheet cassette 111, and the sheet 10
The sheet is fed on the U-turn guide member 108 as a reversing guide member having a concave reversing curved surface 108a for reversing the feeding direction of 1.

Then, the separated and fed sheet 101 conveys the conveying roller 106 which is constantly rotating during rotation of a main motor (not shown), a driven roller 107 which is rotated by the conveying roller 106, and the sheet 101. The pair of registration rollers 109, which are provided so as to be able to move in and out of the conveyance path constituted by the guides 110, and the pair of upper and lower guide plates 113 and 114, which guide the sheet 101 to the transfer means (not shown), are inverted to 180 ° After that, the toner image is transferred to the transfer unit and the toner image is transferred.
After being heated and fixed by a fixing unit (not shown),
It is discharged to the outside of the device.

The rear end of the sheet 101 is a sheet cassette 111.
12 when leaving the U-turn guide member 108.
Since there is a drop between points A and B, the tip of the U-turn guide member 108 on the side of the sheet cassette 111 (position of point B) and the rear end of the sheet 101 collide with each other depending on the strength of the sheet 101, which is large. Impact noise may be generated, or abnormal noise may be generated by the bounce of the seat 101 itself.

As a conventional technique for preventing the generation of such an impulsive sound and a strange noise due to a bounce, an auxiliary guide member 120 is attached to the U-turn guide member 108 as shown in FIG. 13, or shown in FIG. As described above, there is a structure in which the auxiliary guide member 121 is attached to the sheet cassette 111 so that the rear end of the sheet 101 reaches the U-turn guide member 108 smoothly from the sheet cassette 111.

[0007]

However, in the above-mentioned conventional technique, in the case of the sheet feeding apparatus shown in FIG. 13, the step C between the auxiliary guide member 120 and the sheet cassette 111 for conveying the sheet 101 has a structure. Is necessary. Since the auxiliary guide member 120 and the sheet cassette 111 are formed separately, the tolerance of the step C varies, and when the step C is large, a large collision occurs when the rear end of the sheet 101 comes into contact with the auxiliary guide member 120. There is a problem that sound is generated or abnormal noise is generated due to the momentum of the seat itself.

When the U-turn guide member 108 is rotated around the shaft 108a in the direction of arrow a in FIG. 13 in order to remove the sheet jammed in the vicinity of the separating claw 112, the auxiliary guide member 12
Since the 0 and the U-turn guide member 108 are integrally formed, the auxiliary guide member 120 also rotates in association with the protrusion, and thus the auxiliary guide member 120 hinders the work of removing the sheet jammed in the vicinity of the separation claw 112. There was a problem of becoming.

Further, in the case of the sheet feeding device shown in FIG.
Since the sheet cassette 111 and the auxiliary guide member 121 are integrally formed, the sheet cassette 111 can be used to replenish sheets.
There is a problem that the auxiliary guide member 121 is likely to be damaged when the 111 is pulled out from the apparatus body or attached to the apparatus body.

In the case of so-called front loading for removing the sheet cassette 111 in the direction perpendicular to the paper surface in FIG. 14 (removing the sheet mounting table in a direction orthogonal to the sheet feeding direction), it is necessary to retract the auxiliary guide member 121. However, there is a problem in that the retracting mechanism becomes complicated.

The present invention solves the above-mentioned problems.
The purpose is to maintain the operability of sheet replenishment and jam processing and reduce the occurrence of collision noise when the sheet collides with the reversing curved surface of the reversing guide member and abnormal noise of the sheet itself popping. A sheet feeding apparatus and an image forming apparatus including the sheet feeding apparatus are provided.

[0012]

A typical structure according to the present invention for achieving the above-mentioned object is a sheet mounting table on which sheets are stacked, and a sheet stacked on the sheet mounting table is fed in a predetermined direction. A sheet feeding device comprising: a sheet feeding device for performing sheet feeding; and a reversing guide member having a concave reversing curved surface for reversing the feeding direction of the sheet fed by the sheet feeding device, the device body or the While being supported by either one of the reversing guide members, it has an auxiliary guide member arranged in the vicinity of the reversing curved surface of the reversing guide member on the sheet mounting table side, and the auxiliary guide member,
When the sheet mounting table is mounted on the apparatus main body, the sheet mounting table is positioned by the biasing means that exerts a predetermined suction force or pressing force on the sheet mounting table, and when the sheet mounting table is detached from the apparatus main body. The sheet feeding device is configured to be separated from the sheet mounting table.

In the sheet feeding device in which the auxiliary guide member is supported by the reversal guide member, the auxiliary guide member is housed in the reversal guide member when the reversal guide member is retracted. It is characterized by being configured.

Further, the image forming apparatus according to the present invention forms an image on the sheet conveyed by the sheet conveying device and the sheet conveyed by the sheet conveying device according to image information. An image forming apparatus comprising: a recording unit for recording.

[0015]

Since the sheet feeding device according to the present invention is configured as described above, the sheet reversing guide member for reversing the sheet fed from the sheet placing table by the sheet feeding means has the inverted curved surface on the sheet placing table side. By providing the auxiliary guide member in the vicinity, the step difference from the sheet mounting table to the reversing guide member is reduced, and the rear end of the sheet fed by the sheet feeding means first comes into contact with the lower end of the reversing curved surface. It is possible to reduce the occurrence of collision noise and abnormal noise caused by the seat itself popping.

That is, since the auxiliary guide member is positioned with respect to the sheet mounting table by the biasing means, the step difference between the sheet mounting table and the auxiliary guide member is constant, and the sheet can be smoothly guided. Therefore, it is possible to reduce the collision noise between the rear end of the sheet and the auxiliary guide member and the abnormal noise of the sheet itself popping.

Further, since the sheet placing table and the auxiliary guide member are separable from each other, side replenishment (dismounting the sheet placing table in the sheet feeding direction) from the apparatus main body when replenishing the sheet placing table with sheets or The auxiliary guide member will not be damaged even when the sheet mounting table is pulled out by the front loading (the sheet mounting table is attached / detached in the direction orthogonal to the sheet feeding direction) or attached to the main body of the apparatus, and sheet replenishment work is performed. The auxiliary guide member does not interfere.

When the auxiliary guide member is supported by the reversing guide member and can be housed in the reversing guide member, the reversing guide member is retracted to remove the sheet jammed in the vicinity of the separating claw. At this time, the auxiliary guide member is accommodated in the reversing guide member in conjunction with the retracting operation of the reversing guide member, so that the auxiliary guide member does not interfere with the sheet jam processing operation.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a sheet feeding apparatus and an image forming apparatus having the same according to the present invention will be specifically described with reference to the drawings. 1 is a sectional explanatory view showing an image forming apparatus equipped with a sheet feeding apparatus of the present invention, FIG. 2 is a sectional explanatory view showing a first embodiment of the sheet feeding apparatus of the present invention, and FIG. 3 is a first embodiment. In the example, a sectional explanatory view showing a state in which the sheet mounting table is pulled out, FIG. 4 is a sectional explanatory view showing a state in which the reversal guide member is rotated in the first embodiment, and FIG. 5 is a configuration of the reversal guide member and the sheet guide member. FIG.

The electrophotographic image forming apparatus shown in FIG. 1 is equipped with a sheet feeding device according to the present invention, which will be described later in detail, and irradiates a light image based on image information from the reading means 1 to carry an image. A latent image is formed on an electrophotographic photosensitive member, which is a body, and the latent image is converted into a toner image by a developing unit, and a sheet 2 made of a predetermined material such as paper or synthetic resin is fed from a sheet feeding device. It is to be transcribed.

The reading means 1 irradiates a document placed on the document glass 1a with the image surface facing downward from a light source 1b, and reflects the reflected light through a plurality of mirrors 1c and a focusing lens 1d. The photosensitive drum 3a, which is an electrophotographic photosensitive member, in the process cartridge 3 is irradiated with the latent image to form a latent image, and the latent image is visualized as a toner image by developing means.

On the other hand, in synchronization with the formation of the image, the sheets 2 stacked in the sheet cassette 4 serving as the sheet mounting table are fed by the feeding roller 5 serving as the sheet feeding means, and the U-turn guide serving as the reversing guide member. Sheet 2 by member 6
In the image forming portion which is conveyed by the sheet conveying means including the pair of registration rollers 7 and which is formed as the process cartridge 3, and the toner image formed on the photosensitive drum 3a is transferred to the transfer roller 8 as the transfer means. The voltage is applied to the sheet 2 to transfer it to the sheet 2, and the sheet 2 is conveyed to the fixing unit 10 by the conveying belt 9.

The fixing means 10 comprises a fixing rotator 10a having a heater and a driving roller 10b for pressing and conveying the sheet 2 to the fixing rotator 10a.
The toner image is fixed by applying heat and pressure when passing between a and the driving roller 10b. And fixing means
The sheet 2 that has passed 10 is discharged by the discharge roller pair 11.

Next, the first sheet feeding apparatus according to the present invention will be described.
An example will be described with reference to FIGS. In the sheet feeding apparatus of the first embodiment, a large number of sheets 2 are stacked in a sheet cassette 4, and a compression spring 12 is used to press a middle plate 13 from below.
The uppermost sheet 2 pressed by the feeding roller 5 through the sheet feeding roller 5 is rotatably supported by the feeding shaft 14 and intermittently rotates so that the sheet cassette 4 is fed at a predetermined timing. There is.

Sheet 2 fed by feeding roller 5
Is separated into one sheet by separating claws 15 provided at both front and rear corners of the sheet cassette 4 (here, "front" means the right direction on the paper surface of FIG. 2), and the separated and fed sheet 2 is fed. It is fed to the U-turn guide member 6 having a concave curved surface 16 that reverses the feeding direction by approximately 180 °.

The sheet 2 curved along the reverse curved surface 16 is formed by a conveying roller 17 which is constantly rotating during rotation of a main motor (not shown), and a slip roller 18 which is rotated by the conveying roller 17. It is pinched and conveyed, and U
A pair of registration rollers 7 and an upper and lower pair which are provided so as to be able to enter and retract in a sheet conveyance path formed by a turn guide member 6 and a conveyance guide 19 having a curved surface corresponding to the inverted curved surface 16 of the U-turn guide member 6. It is conveyed to the above-mentioned transfer position by the guide plates 20 and 21.

As shown in FIG. 5, the U-turn guide member 6 has ribs 22 each having a curved surface corresponding to the inverted curved surface 16 arranged at a predetermined interval. In the vicinity of the lower end 22a of the rib located at the lower end,
As shown in FIG. 2, it is slidably supported by guides 23 and 24 fixed to the U-turn guide member 6, and at least one end thereof is engaged with a tension spring 25 fixed to the U-turn guide member 6. One auxiliary guide member 26 is arranged.

Both end portions of the auxiliary guide member 26 are restricted by the guides 23 and 24, and the movable range in the vertical direction in FIG. 2 is restricted. In addition, a long hole 26 is provided at a predetermined position of the auxiliary guide member 26.
b is bored, fitted in the elongated hole 26b, and U
A shaft 27 fixed to the turn guide member 6 restricts the movable range of the auxiliary guide member 26 in the left-right direction in FIG. 2 within the length range of the elongated hole 26b. A concave hole 26a is formed at a position of the auxiliary guide member 26 facing the sheet cassette 4, and a magnet 28 is arranged on the outer peripheral portion of the hole 26a.

Further, in the sheet cassette 4, a projection 4a having a size corresponding to the size of the hole 26a is provided at a position facing the hole 26a of the auxiliary guide member 26. A magnet 29 is arranged at a position facing the magnet 28 on the outer periphery of 4a.

The magnets 28 and 29 are arranged so that the N and S poles thereof face each other, and the sheet cassette 4 and the auxiliary guide member.
A predetermined suction force acts on the sheet cassette 26 and the sheet cassette 4 and the U-turn guide member 6 are in contact with each other or are attracted to each other while maintaining an extremely short distance.

With the above structure, the protrusion 4a of the sheet cassette 4 is fitted into the hole 26a of the auxiliary guide member 26, and the auxiliary guide member 26 is attached to the sheet cassette 4 by the attraction force of the magnets 28 and 29. The positioning can be done reliably.

A sheet guide member 30, which is bent upward at a predetermined angle or curved at a predetermined curvature in FIG. 2 for guiding the conveyance of the sheet 2, is fixed to the upper portion of the auxiliary guide member 26. The sheet 2 separated and conveyed from the sheet cassette 4 by the guide member 30 is smoothly conveyed along the upper surface of the sheet guide member 30.

As shown in FIG. 5, the sheet guide member 30 is formed so that one end thereof has a cutout portion 30a corresponding to the width of the rib 22 located on the inverted curved surface 16, and the cutout portion is formed.
One end of the sheet guide member 30 is configured to be able to escape between the ribs 22 via the 30a. As a result, the sheet guide member 30 is conveyed on the sheet guide member 30 and the ribs.
The leading end of the sheet 2 that is in contact with the intersection 31 with 22 can smoothly enter the U-turn guide member 6.

When the leading edge of the sheet 2 further enters the U-turn guide member 6, the sheet 2 is curved along the sheet conveying path formed by the inverted curved surface 16 of the U-turn guide member 6. The sheet guide member 30 is pushed downward by the elastic force of the sheet 2 itself generated by the curved shape of the sheet 2, and the reversing curved surface 16, the conveying roller 17, the slip roller
18, transport guide 19, registration roller pair 7, pair of guide plates
Sheets 2 and 20 are completely inverted by 180 °.

At this time, the elasticity of the sheet 2 is maximized, but the rear end of the sheet 2 which has left the separation claw 15 is smoothly conveyed along the sheet guide member 30, so that the rear end of the sheet 2 is rib 22. It is possible to reduce the occurrence of a collision noise and an abnormal noise caused by the popping of the sheet 2 itself when abutting on the intersection 31 between the sheet guide member 30 and the sheet guide member 30.

Further, as shown in FIG. 3, when the sheet cassette 4 is pulled out from the main body of the apparatus against the attraction force of the magnets 28 and 29 for replenishing sheets, the auxiliary guide member 26 and the sheet cassette 4 are separated. Therefore, the auxiliary guide member 26 does not hinder the sheet replenishing work to the sheet cassette 4.

Incidentally, the auxiliary guide member 26 and the sheet cassette 4
Is separated, the auxiliary guide member 26 is pulled by the tension spring 25 arranged in the U-turn guide member 6 to guide 23,
It is adapted to be housed inside the U-turn guide member 6 along 24. At this time, the sheet guide member 30 fixed to the U-turn guide member 6 escapes between the ribs 22 as shown in FIG.

When the sheet cassette 4 is attached to the main body of the apparatus after replenishing the sheets, the attraction force of the magnets 28 and 29 pulls the spring.
The auxiliary guide member 26 jumps out of the U-turn guide member 6 by overcoming the pulling force of 25, the projection 4a of the sheet cassette 4 is fitted into the hole 26a of the auxiliary guide member 26, and the magnet
The auxiliary guide member 26 can be reliably positioned with respect to the sheet cassette 4 by the suction force of 28 and 29.

As described above, since the auxiliary guide member 26 is configured to be surely positioned with respect to the sheet cassette 4, the step difference between the sheet cassette 4 and the sheet guide member 30 on the auxiliary guide member 26 is minimized. The sheet 2 that has exited the sheet cassette 4 is configured by
The rear end of the sheet guide member on the auxiliary guide member 26 smoothly
Since the sheet 2 is conveyed to the upper surface of the sheet 30, it is possible to reduce the generation of a collision sound when the rear end of the sheet 2 comes into contact with the sheet guide member 30 and the generation of an abnormal noise due to the bounce of the sheet 2 itself.

The sheet 2 clogged near the separating claw 15
When the U-turn guide member 6 is rotated about the shaft 32 by 90 ° in the direction of arrow a in FIG. 2 in order to remove it, the auxiliary guide member 26 is restricted by the guides 23 and 24 as shown in FIG. It rotates in conjunction with the member 6.

At this time, the detaching force due to the rotation overcomes the attractive force of the magnets 28, 29, and the projection 4a of the sheet cassette 4 and the hole 26a of the auxiliary guide member 26 are disengaged. Then, the auxiliary guide member 26 is released from the restraint from the magnets 28 and 29, and is housed inside the U-turn guide member 6 by the extension spring 25 as described above, and the sheet guide member 30 is provided with the rib 22 as shown in FIG.
Run away during.

Therefore, the auxiliary guide member 26, the sheet guide member 30 and the like do not interfere with the jam processing work for removing the sheet 2 jammed in the vicinity of the separating claw 15, and the jam processing can be performed smoothly as usual. is there.

Next, the second sheet feeding apparatus according to the present invention
An example will be described with reference to FIGS. FIG. 6 is a sectional explanatory view showing a second embodiment of the sheet feeding apparatus according to the present invention, FIG. 7 is a sectional explanatory view showing a state in which the sheet placing table is pulled out in the second embodiment, and FIG. 8 is a second embodiment. FIG. 7 is a cross-sectional explanatory view showing a state in which the inversion guide member is rotated in FIG. The same members as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

In FIG. 6, the auxiliary guide member 26 is an arm.
A spring 34 rotatably supported by the U-turn guide member 6 with respect to the rotation center shaft 32 of the U-turn guide member 6 and further fixed to the apparatus main body.
6 is supported from below in FIG. The spring 34 is set to have a natural length when the auxiliary guide member 26 is in the posture shown in FIG. 6, and the action of the spring 34 restricts the movable range of the auxiliary guide member 26 in the vertical direction in FIG. The posture of the auxiliary guide member 26 can always be kept constant.

Similar to the first embodiment, holes 26a and 26a are provided at the positions of the auxiliary guide member 26 facing the sheet cassette 4 and the positions of the sheet cassette 4 facing the auxiliary guide member 26, respectively.
The protrusion 4a and the magnets 28 and 29 are arranged.
The hole 26a is fitted in a and the auxiliary guide member 26 is surely positioned with respect to the sheet cassette 4 by the attraction force of the magnets 28 and 29, as in the first embodiment. Other configurations are similar to those of the first embodiment.

Then, as shown in FIG. 7, when the sheet cassette 4 is pulled out from the apparatus main body to replenish the sheet cassette 4 with sheets 2, the auxiliary guide member 26 and the sheet cassette 4 are separated from each other as in the first embodiment. Since they are separated, the auxiliary guide member 26 does not hinder the sheet replenishing work.
At this time, since the auxiliary guide member 26 is supported by the shaft 32 and is restrained by the arm 33 supported by the main body of the apparatus via the spring 34, the auxiliary guide member 26 is held in the same posture.

When the sheet cassette 4 is mounted on the main body of the apparatus after the sheets are replenished, the projection 4a of the sheet cassette 4 is fitted into the hole 26a of the auxiliary guide member 26 and the magnets 28, 29 are inserted.
The auxiliary guide member 26 can be reliably positioned with respect to the sheet cassette 4 by the suction force.

The sheet 2 jammed near the separating claw 15
When the U-turn guide member 6 is rotated about the shaft 32 in the direction of arrow a shown in FIG.
Since the auxiliary guide member 26 is constrained by the magnets 28, 29 and the spring 34 as shown in FIG. 5, it does not rotate in conjunction with the U-turn guide member 6.

Therefore, the auxiliary guide member 26 does not project in the vicinity of the separation claw 15 and does not interfere with the jam processing work for removing the jammed sheet 2. Therefore, the jam clearance work can be performed smoothly as usual.

Next, the third sheet feeding apparatus according to the present invention will be described.
An example will be described with reference to FIGS. 9 to 11. 9 is a sectional explanatory view showing a third embodiment of the sheet feeding device according to the present invention, FIG. 10 is a sectional explanatory view showing a state in which the sheet placing table is pulled out in the third embodiment, and FIG. 11 is a third embodiment. FIG. 7 is a cross-sectional explanatory view showing a state in which the inversion guide member is rotated in FIG. The same members as those in the first or second embodiment are designated by the same reference numerals and the description thereof will be omitted.

In FIG. 9, the auxiliary guide member 26 is supported by the springs 35 and 36 from the two directions, the downward direction and the rightward direction in FIG. The springs 35 and 36 have substantially the same action as the spring 34 shown in the second embodiment,
When the auxiliary guide member 26 is in the posture shown in FIG. 9, the spring 35,
36 is set to have a natural length, and this spring 35,
By the action of 36, the movable range of the auxiliary guide member 26 in the vertical direction and the horizontal direction in FIG. 9 is regulated, and the posture of the auxiliary guide member 26 can be constantly maintained.

As in the first embodiment, holes 26a, 26a are provided at the positions of the auxiliary guide member 26 facing the sheet cassette 4 and the positions of the sheet cassette 4 facing the auxiliary guide member 26, respectively.
The protrusion 4a is disposed, and the hole 26a is fitted into the protrusion 4a by the pressing force of the spring 36 so that the auxiliary guide member 26 is reliably positioned with respect to the sheet cassette 4. Other configurations are similar to those of the first embodiment.

As shown in FIG. 10, when the sheet cassette 4 is pulled out from the apparatus main body to replenish the sheet 2, the auxiliary guide member 26 and the sheet cassette 4 are separated from each other, so that the auxiliary guide member 26 is used for sheet replenishment work. There is no hindrance. At this time, since the auxiliary guide member 26 is supported by the apparatus main body by the springs 35 and 36 and its posture is restrained as described above, the auxiliary guide member 26 is held in the same posture state.

When the sheet cassette 4 is mounted on the main body of the apparatus after the sheets are replenished, the projection 4a of the sheet cassette 4 is fitted into the hole 26a of the auxiliary guide member 26 and the pressing force of the spring 36 causes the sheet cassette 4 to move. Auxiliary guide member
26 can be positioned reliably.

The sheet 2 clogged near the separating claw 15
When the U-turn guide member 6 is rotated about the shaft 32 by 90 ° in the direction of arrow a in FIG. 9 to remove the auxiliary guide member 26, the auxiliary guide member 26 is attached to the main body of the device by the springs 35 and 36 as shown in FIG. Since it is constrained, it does not rotate in conjunction with the U-turn guide member 6.

For this reason, the auxiliary guide member 26 does not project near the separation claw 15 and does not interfere with the jam processing work for removing the jammed sheet 2. Therefore, the jam clearance work can be performed smoothly as usual.

In each of the above embodiments, the sheet guide member
It is preferable to use a sound absorbing member such as maltoprene or a rubber material as the material of the surface of the sheet 30 through which the sheet 2 passes, particularly the surface that receives the rear end of the sheet 2 first, because the sound deadening effect is improved.

Further, by performing a treatment such as sticking a low friction sheet member such as polyester on the sound absorbing member, it is possible to improve slidability when the sheet 2 is fed. preferable.

Further, in each of the above-mentioned embodiments, the U-turn guide member 6 is configured to be axially rotated and retracted in order to remove the clogging of the sheet. However, withdrawal other than rotation, for example, parallel movement or removal. The evacuation method based on the above may be applied.

In the first and second embodiments, the magnets 28 and 29 are set to N
Although it is composed of a pair of magnets having poles and S poles, as another embodiment, one of the magnets 28 and 29 may be composed of a magnet, and the other may be composed of a magnetic material such as an iron plate instead of the magnet. Similar effects can be obtained.

Further, in the same manner as in the first and second embodiments, the third embodiment is additionally provided with a suction means in which one of the magnets 28, 29 is made of a magnetic material such as an iron plate. This is preferable because the alignment with the auxiliary guide member 26 can be improved.

The image forming apparatus provided with the sheet feeding apparatus according to the present invention is applied to the electrophotographic image forming apparatus, but the ink jet recording means, the heat sensitive recording means, the thermal transfer recording means, or the wire dot recording means is used. It is also possible to apply the present invention to an image forming apparatus or the like.

[0063]

Since the sheet feeding device according to the present invention has the above-described structure and operation, it is provided near the lower end of the reversing curved surface of the reversing guide member for reversing the sheet fed from the sheet mounting table. An auxiliary guide member that is gently connected to the inverted curved surface and that can be connected and separated at a small step is provided on the sheet mounting table. The sheet mounting table and the auxiliary guide member are attracted by a magnet or a pressing force of a spring and a sheet. In the case where the projection provided on the mounting table and the recess provided on the auxiliary guide member are configured to be positioned by fitting,
It is possible to reduce the occurrence of a collision noise or a popping noise of the sheet itself when the rear end of the sheet fed from the sheet mounting table by the sheet feeding means first comes into contact with the auxiliary guide member and the reversing guide member.

That is, since the auxiliary guide member and the sheet mounting table are separated when the sheet mounting table is removed from the main body of the apparatus in order to replenish the sheet mounting table, the sheet replenishing work is not hindered.

Further, since the auxiliary guide member can be surely positioned with respect to the sheet mounting table when the sheet mounting table is mounted on the main body of the apparatus after the sheets are replenished, the sheet mounting table and the auxiliary guide member can be reliably positioned. The step can be made as small as possible. According to this structure, it is possible to reduce the occurrence of collision noise when the rear end of the sheet comes into contact with the sheet guide member provided on the auxiliary guide member and abnormal noise due to the bounce of the sheet itself.

When the auxiliary guide member is supported by the reversing guide member, the auxiliary guide member is housed in the reversing guide member when the reversing guide member retracts, so that the auxiliary guide member is accommodated. The sheet guide member does not hinder the sheet jam processing work, and the jam processing can be performed smoothly. Further, when the auxiliary guide member is configured to hold the posture as it is when the reversing guide member retracts, the auxiliary guide member and the sheet guide member may project in conjunction with the retracting operation of the reversing guide member. Since the auxiliary guide member and the sheet guide member do not interfere with the sheet jam processing work, the jam processing can be performed smoothly.

Further, an image forming apparatus equipped with the sheet feeding device is an image forming apparatus which exhibits the action of the sheet feeding device and reduces the occurrence of sheet collision noise and abnormal noise due to sheet bounce. Can be provided.

[Brief description of drawings]

FIG. 1 is a cross-sectional explanatory view showing an image forming apparatus equipped with a sheet feeding apparatus of the present invention.

FIG. 2 is a sectional explanatory view showing a first embodiment of the sheet feeding device according to the present invention.

FIG. 3 is an explanatory sectional view showing how the sheet mounting table is pulled out in the first embodiment.

FIG. 4 is an explanatory sectional view showing a state in which the reversal guide member is rotated in the first embodiment.

FIG. 5 is a perspective view showing configurations of an inversion guide member and a sheet guide member.

FIG. 6 is a sectional explanatory view showing a second embodiment of the sheet feeding device according to the present invention.

FIG. 7 is an explanatory sectional view showing how the sheet placing table is pulled out in the second embodiment.

FIG. 8 is an explanatory sectional view showing a state in which the reversal guide member is rotated in the second embodiment.

FIG. 9 is a sectional explanatory view showing a third embodiment of the sheet feeding apparatus according to the present invention.

FIG. 10 is a cross-sectional explanatory view showing a state in which the sheet mounting table is pulled out in the third embodiment.

FIG. 11 is an explanatory sectional view showing a state in which the reversal guide member is rotated in the third embodiment.

FIG. 12 is a diagram illustrating a conventional example.

FIG. 13 is a diagram illustrating a conventional example.

FIG. 14 is a diagram illustrating a conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Reading means, 1a ... Original glass, 1b ... Light source, 1c ...
Mirror, 1d ... Focusing lens, 2 ... Sheet, 3 ... Process cartridge, 3a ... Photosensitive drum, 4 ... Sheet cassette, 4a ... Projection part, 5 ... Feed roller, 6 ... U-turn guide member, 7 ... Registration roller Pair, 8 ... Transfer roller, 9 ... Conveying belt, 10 ... Fixing means, 10a ... Fixing rotator, 10b ... Driving roller, 11 ... Discharge roller pair, 12 ... Compression spring, 13 ... Middle plate, 14 ... Feeding shaft, 15 ... Separation claw, 16 ... Inverted curved surface, 17 ... Conveying roller, 18 ... Slip roller, 19 ... Conveying guide, 20, 21
... Guide plate, 22 ... Rib, 22a ... Rib lower end, 23, 24 ... Guide, 25 ... Extension spring, 26 ... Auxiliary guide member, 26a ...
Hole, 26b ... Slot, 27 ... Shaft, 28, 29 ... Magnet, 30 ... Sheet guide member, 30a ... Notch, 31 ... Intersection, 32 ... Shaft, 33 ... Arm, 34, 35, 36 ... Spring

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display G03G 15/00

Claims (3)

[Claims] 1. A sheet mounting table for stacking sheets, a sheet feeding unit for feeding the sheets stacked on the sheet mounting table in a predetermined direction, and a sheet feeding unit for feeding the sheets fed by the sheet feeding unit. In a sheet feeding device including a reversing guide member having a concave reversing curved surface for reversing a direction, the reversing guide member is supported by either the apparatus main body or the reversing guide member, and the reversing guide member is mounted on the sheet. The auxiliary guide member is disposed in the vicinity of the inverted curved surface on the table side, and the auxiliary guide member has a predetermined suction force or pressing force against the sheet table when the sheet table is attached to the apparatus main body. The sheet is positioned by the urging means that exerts the force, and is separated from the sheet mounting table when the sheet mounting table is detached from the apparatus main body. Feeding device. 2. The sheet feeding apparatus according to claim 1, wherein the auxiliary guide member is supported by the reversal guide member, and the auxiliary guide member is disposed inside the reversal guide member when the reversal guide member is retracted. A sheet feeding device, which is configured to be stored. 3. A sheet conveying unit configured to convey a sheet fed by the sheet feeding apparatus according to claim 1 or 2, and an image on the sheet conveyed by the sheet conveying unit according to image information. An image forming apparatus comprising: a recording unit for recording.