JPH11171352A - Sheet supplying device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To lower a tray for the same lowering time, regardless of the amount of loaded sheets, by switching damping force of a damping means by reaction force acted from a revolving body interlocking with a winding shaft of wire elevating and lowering a sheet loading means and working a damping action according to lowering speed of the tray. SOLUTION: A winding shaft gear 9 revolves according to the lowering of a tray. A first damp gear 11 has damping force which is increased and decreased according to revolving speed, damping force imparting to the first damper gear 11 is increased according to a rise in revolving speed and reaction force acting on the first damper gear 11 from the winding shaft gear 9 is also increased in proportion to this damping force. When a link arm 12 supporting the first damper gear 11 becomes prescribed reaction force or more, the link arm 12 rotates clockwise in the same direction as the revolving direction of the winding shaft gear 9 from its stationary location by gravity of a damper mechanism 10 and is switched to a state that damping force is increased because a second damper gear 13 is engaged with the winding gear 9.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a large-capacity sheet feeding apparatus used for an image forming apparatus such as a printer or a copying machine.

[0002]

2. Description of the Related Art In an apparatus for stacking large-capacity sheets and sequentially supplying the sheets to an image forming apparatus such as a printer or a copier, when lowering a tray for stacking sheets such as when pulling out a storage, The descent speed is attenuated using dampers. Conventional sheet feeding device,
This will be described with reference to FIG. FIG. 8 is an explanatory view of a sheet stacking portion of a conventional sheet feeding apparatus.

[0006] The sheet supply means 50 shown in FIG. 6 has a tray 52 in which sheets can be loaded and lowered in a storage 51, and is connected to a winding drum 54 by a lifting wire 53. A drive transmission gear 58 is attached to the winding drum 54, and the driving force of the drive motor 55 is transmitted through the drive transmission gears 57 and 56.

A take-up shaft gear is provided on the take-up drum 54.
59 is attached, and is configured to connect to and rotate the damper connection gear 60. Damper connection gear
A damper gear 61 is attached to a damper side plate 62.
It is connected to the.

[0005] The storage case 51 is configured such that the driving gear 57 and the driving gear 58 are engaged with each other to be transmitted to the driving force by being housed in the sheet feeding device main body. Here, when the storage case 51 is pulled out from the sheet feeding device main body in a state where the tray 52 is raised, the engagement between the drive transmission gear 57 and the drive transmission gear 58 is released, and the tray 52 is lowered.

At this time, since the tray 52 and the take-up drum 54 are connected by the lifting wire 53, the take-up drum 54 rotates as the tray 52 descends. As a result, a winding shaft gear 59 coaxially arranged with the winding drum 54.
Also rotate, and rotate the damper gear 61 via the damper connection gear 60. The damper gear 61 generates a resistance against rotation, and the descending speed of the tray 52 is attenuated.

[0007]

However, in the above-mentioned conventional sheet feeding apparatus, a constant resistance force is always generated by the damper, so that the tray descending speed varies depending on the amount of sheets stacked on the tray. In particular, in the case of a large-capacity sheet feeding apparatus, the load of the sheet greatly differs between the case where a large number of sheets are stacked and the case where the sheet is not stacked, and the lowering speed of the tray is also significantly different.

Further, since the damping function is normally set to work effectively when a large number of sheets are stacked, the tray descends for a long time in the case of an empty load, and the user loads the next sheet. In this case, the user has to wait until the tray descends.

In view of the above problems, the present invention makes it possible to lower the tray in the same descent time irrespective of the number of loaded sheets by exerting a damping action on the lowering speed according to the lowering speed of the tray. It is intended to provide a sheet feeding device.

[0010]

A typical configuration of a sheet feeding apparatus according to the present invention includes a stacking unit for stacking sheets to be supplied, a wire connected to the stacking unit for raising and lowering the stacking unit, and a wire. A storage shaft including a take-up shaft, a damping unit for attenuating the rotation of the take-up shaft, and a driving force transmitting unit connected to the take-up shaft, and a driving device for applying a driving force to the driving force transmitting unit. A sheet feeding device configured to separate the driving device and the driving force transmission unit so that the stacking unit falls, and a rotating body interlocked with rotation of a winding shaft of the wire; Damping means rotatably connected to the rotating body for applying a damping force, and damping force switching means for switching the damping force of the damping means by a reaction force acting on the damping means from the rotating body. The features.

[0011]

[First Embodiment] A first embodiment of a sheet feeding apparatus according to the present invention will be described with reference to the drawings. 1 is an overall perspective view of the sheet feeding apparatus according to the present embodiment, FIG. 2 is a side view of the damping unit, FIG. 3 is a front view of the damping unit, and FIG.

The sheet supply means A shown in FIG.
A tray 2 on which sheets can be loaded and moved up and down is arranged. The tray 2 is connected to a winding drum 4 by a lifting wire 3. Winding shaft 4 of winding drum 4
A drive transmission gear 8 is attached to a, and the driving force of the drive motor 5 is transmitted through the drive transmission gears 7 and 6.

The storage 1 is configured to receive the driving force by being housed in the main body of the sheet feeding device so that the drive transmission gear 7 and the drive transmission gear 8 mesh with each other. On the other hand, when the storage 1 is pulled out of the sheet feeding apparatus main body with the tray 2 raised, the engagement between the drive transmission gear 7 and the drive transmission gear 8 is released, and the tray 2 is lowered.

At this time, since the tray 2 and the take-up drum 4 are connected by the lifting wire 3, the take-up drum 4 rotates as the tray 2 descends. A take-up shaft gear 9 is attached to the end of the take-up shaft 4a opposite to the drive transmission gear 8, and a damper mechanism 10 as damping force switching means is further attached to the take-up shaft gear 9. I have.

The damper mechanism 10 has a first damper gear 11 and a second damper gear 13 as damping means. The first damper gear 11 is rotatably mounted around the take-up shaft gear 9 by a link arm 12 and can rotate while being joined to the take-up shaft gear 9. The second damper gear 13 is rotatably mounted about a support shaft 15 by a link arm 14.
Is configured to be able to be separated from and connected to.

The link arm 12 is formed in a T-shape, and has an engaging portion 12a at its tip. On the other hand, the link arm 14 is provided with a link groove 14a,
12a is slidably fitted. Therefore the link arm
When the first damper gear 11 rotates, the second damper gear 13
Will also rotate. The link arm 12 is provided with a stopper 16 that regulates one of the movements, and regulates the rotation angle of the first damper gear 11.

That is, the damper mechanism 10 is a link mechanism in which the link shaft 12 and the link arm 14 are connected to each other by the engagement portion 12a and the link groove 14a using the shaft center of the winding shaft gear 9 and the support shaft 15 as fixed support shafts. It is configured. The swing range of the link mechanism is regulated by the stopper 16.

Next, the operation will be described. While the storage 1 is attached to the sheet feeding device main body, the tray 2 is at a position where the tray 2 is raised to supply sheets. When the take-up shaft gear 9 is in a stopped state, the link arm 12 abuts against the stopper 16 due to the weight of the damper mechanism 10, and the second damper gear 13 is moved from the take-up shaft gear 9 as shown in FIG. It is in a separated state.

When the storage 1 is pulled out from the sheet feeding apparatus main body, the drive transmission gear 7 and the drive transmission gear 8 are disengaged from each other as described above, and the tray 2 descends. The wire 3 is sequentially sent out from the winding drum 4 as the tray 2 moves down, and the winding shaft 4a and the winding shaft gear 9 are rotated clockwise in FIG.

Here, since the first damper gear 11 is engaged with the winding shaft gear 9, the first damper gear 11 starts rotating with the rotation of the winding shaft gear 9. The first damper gear 11 increases or decreases the damping force according to the rotation speed. Accordingly, as the rotational speed increases, the damping force applied by the first damper gear 11 to the winding shaft gear 9 increases, and the reaction force acting on the first damper gear 11 from the winding shaft gear 9 increases in proportion thereto. .

Then, the link arm 12 supporting the first damper gear 11 is rotatable about the winding shaft gear 9, so that when the reaction force exceeds a predetermined reaction force, the link arm 12 is taken up from a stationary position due to its own weight of the damper mechanism 10. It rotates clockwise in the same direction as the rotation direction of the shaft gear 9. With this, the link arm
14 also rotates about the support shaft 15, and the second damper gear 13 meshes with the winding shaft gear 9.

As a result, the two damper gears 11 and 13 mesh with the winding shaft gear 9, and the state is switched to a state where the damping force is increased. If the rotation speed of the take-up shaft gear 9 drops below a predetermined value, the self-weight of the damper mechanism 10 exceeds the reaction force of the first damper gear 11, so that the second damper gear 13 is separated from the take-up shaft gear 9 The engagement is released, and the damping force is switched to the reduced state. In this way, the action of the damping force can be switched according to the descending speed of the tray.

[Second Embodiment] Next, a second embodiment of the present invention will be described with reference to the drawings. FIG. 5 is an enlarged view of the damping means of the sheet feeding device according to the present embodiment. The same reference numerals are given to the same portions as those in the first embodiment, and the description is omitted.

In the damper mechanism 17 as the damping means according to the present embodiment, the link arm 14 of the second damper gear 13 is provided with a stopper locking portion 14b as the moving load means. The stopper locking portion 14b has flexibility, and is configured to engage with the stopper 16 when the second damper gear 13 is engaged with the winding shaft gear 9.

In this damper mechanism 17, the first damper gear 11 meshes with the winding shaft gear 9 as in the first embodiment, and the first damper gear 11 is attenuated as the rotation speed of the winding shaft gear 9 increases. The force also increases, and the reaction force that the first damper gear 11 receives from the winding shaft gear 9 also increases. When a predetermined or more reaction force is applied, the first damper gear 11 rotates around the winding shaft gear 9, the link arm 14 rotates by the link mechanism, and the second damper gear 13 moves to the winding shaft gear 9. Move towards.

The link arm 14 rotates to stop the stopper.
When the stopper 14b comes into contact with the stopper 16, the stopper locking portion 14b is deformed along the stopper 16 as shown in FIG. 5B, and is engaged as shown in FIG. 5A. Thus, a damping force is generated by the two damper gears of the first damper gear 11 and the second damper gear 13, that is, the damping force can be switched.

When the remaining number of sheets loaded on the tray 2 is equal to or less than a predetermined value, the rotation speed of the winding shaft gear 9 is reduced by the action of the first damper gear 11 and the second damper gear 13. Then, the reaction force that the first damper gear 11 receives from the winding shaft gear 9 also decreases. However, even when the second damper gear 13 separates from the winding shaft gear 9, the stopper locking portion 14b needs to be deformed. Therefore, the second damper gear 13 is kept in contact with the winding shaft gear 9 until the predetermined reaction force further decreases. Maintain the engaged state.

That is, in order for the second damper gear 13 to mesh with the take-up shaft gear 9, a reaction force combining the own weight of the damper mechanism 10 and the force for deforming the stopper locking portion 14b is required. On the other hand, to release the engagement, the damper mechanism
The reaction force must be reduced until the stopper locking portion 14b is deformed by its own weight of 10.

From this, the reaction force for releasing the engagement is smaller than the reaction force required for the engagement, and once the second damper gear 13 and the winding shaft gear 9 are engaged, the predetermined rotation is required. The meshing is continued until the speed decreases. Accordingly, when the reaction force due to the lowering speed of the tray 2 that has become constant due to the action of the first damper gear 11 and the reaction force at which the second damper gear 13 meshes with the winding shaft gear 9 are matched, the second damper gear 13 The engagement with the winding shaft gear 9 can be prevented from becoming vibratory.

[Third Embodiment] Next, a third embodiment of the present invention will be described with reference to the drawings. FIG. 6 is an enlarged view of the damping means of the sheet feeding device according to the present embodiment. For the overlapping part of the description with the first and second embodiments,
The same reference numerals are given and the description is omitted.

In FIG. 6, the winding shaft gear 9 has an arrow R
The direction of the reaction force that the second damper gear 13 receives from the winding shaft gear 9 when the second damper gear 13 rotates in the direction is indicated by an arrow F.
In the damper mechanism 18 which is the damping means according to the present embodiment, the rotation center of the link arm 19 supporting the second damper gear 13 is moved in the direction F of the reaction force (the pressure angle between the second damper gear 13 and the take-up shaft gear 9). ) Is located below the extension line in the figure. Thereby, the take-up shaft gear 9 of the second damper gear 13
Is set at a predetermined angle with respect to the radial direction of the winding shaft gear 9.

As in the above embodiments, the lowering speed of the tray 2 increases and the reaction force of the first damper gear 11 increases, whereby the second damper gear 13 meshes with the winding shaft gear 9. Then, since the support shaft 15 is disposed below the direction F of the reaction force, the reaction force of the second damper gear 13 acts in the direction of pressing the link arm 19 against the stopper 16.

That is, when the damper mechanism 18 is operated and the second damper gear 13 once meshes with the winding shaft gear 9, the second damper gear 13 transmits the first damper gear transmitted through the link arms 12 and 19 to the second damper gear 13. The reaction force, the own weight of the link arms 12, 19 and the second damper gear 13, and the urging force due to the reaction force of the second damper gear 13 act. Therefore, the second damper gear 13
The first damper gear 11 for separating from the winding shaft gear 9
Is smaller than the reaction force for engagement.

Accordingly, when the reaction force due to the lowering speed of the tray 2 that has become constant by the action of the first damper gear 11 and the reaction force at which the second damper gear 13 meshes with the winding shaft gear 9 match, It is possible to prevent the engagement between the damper gear 13 and the winding shaft gear 9 from becoming vibrating.

In each of the above embodiments, the first damper gear 11, the second damper gear 13, and the take-up shaft gear 9 are configured to operate the damper. The outer periphery of the body may be formed.

In each embodiment, only one damper gear is used for switching the damping force. However, the damping force may be increased and decreased stepwise by using a plurality of damper gears. Furthermore, although the rotating body that meshes with the damper gear is shown attached to the take-up shaft 4a, a separate rotating shaft may be provided to rotate in conjunction with the lowering of the tray 2.

The operation of the damper mechanism is performed by the weight of the damper mechanism and the reaction force of the first damper gear 11. However, a biasing means such as a spring is provided in the damper mechanism, and the damper mechanism is operated by the reaction force. It may be configured to operate.

Here, the structure of the image forming means B to which the sheet feeding means A is connected will be schematically described with reference to FIG.
Note that the sheet feeding device A also serves as a frame on which the image forming means B is placed, and the sheets P stacked on the tray 2 of the sheet feeding means A are sent out by the pickup roller 20 from the uppermost position, and the feed roller 21 and the retard Image forming means B separated one by one by rollers 22
Supplied to

The apparatus main body of the image forming means B is provided with front loading type sheet cassettes 111 and 112 which are mounted from the front. Sheet cassette 111,
The sheet P accommodated in the pickup roller 113
, 114 and feed rollers 115, 117 and retard rollers 116, 118, which are separated and fed one by one. These sheet cassettes 111 and 11
2 and the sheet P sent from the sheet supply means A, an image is formed in the image forming section 101.

The image forming section 101 has a process cartridge 102 detachable from the printer main body. The process cartridge 102 includes an electrophotographic photosensitive drum 103 serving as an image carrier, and a charging means for charging the surface of the photosensitive drum 103. 104, developing means 105 for forming a toner image on the photosensitive drum 103, cleaning means 106 for removing the toner image remaining on the surface of the photosensitive drum 103, and the like. The photosensitive drum 103 scans the scanner unit 1 according to the image signal.
It is exposed by the image light emitted from 07.

The image forming section 101 also includes the photosensitive drum 10
A transfer roller 108 for transferring the toner image formed on the surface of No. 3 onto the sheet P is provided. This transfer roller
Reference numeral 108 denotes a member for pressing the sheet fed from the sheet cassettes 111 and 112 or the sheet supply means A to the photosensitive drum 103. By applying a voltage having a polarity opposite to that of the toner image to the transfer roller 108, the toner on the surface of the photosensitive drum 103 is changed. The image is transferred to sheet P.

A fixing section 109 is provided downstream of the image forming section 101. A fixing roller 110 is disposed in the fixing unit 109, and the toner image transferred to the sheet in the image forming unit 101 is fixed by applying heat and pressure by the fixing roller 110. Then, the sheet on which the toner image is fixed is discharged onto the discharge tray 119.

[0043]

With the above configuration, the sheet feeding apparatus according to the present invention can exert a damping action on the descending speed of the tray according to the descending speed of the tray. The tray can be lowered in the descent time. Therefore, the tray can be safely lowered even when a large number of sheets are loaded, and even when the remaining amount of sheets is small or empty, the tray can be lowered quickly to reduce the user's waiting time. Can be.

Further, by providing a moving load means on the oscillating damper gear or by setting the moving direction of the second damper gear with respect to the rotating body at a predetermined angle with respect to the radial direction of the rotating body, the characteristics of the damper can be improved. Even at a boundary speed determined by the weight of the tray including the remaining sheets, the engagement and release of the damper gear and the outer gear can be smoothly lowered without becoming oscillating.

[Brief description of the drawings]

FIG. 1 is an overall perspective view of a sheet feeding device according to a first embodiment.

FIG. 2 is a side view of the damping means.

FIG. 3 is a front view of the damping means.

FIG. 4 is an explanatory diagram of an operation of a damping unit.

FIG. 5 is an enlarged view of a damping unit of the sheet feeding device according to the second embodiment.

FIG. 6 is an enlarged view of a damping unit of a sheet feeding device according to a third embodiment.

FIG. 7 is a schematic configuration diagram of an image forming apparatus according to an embodiment of the present invention.

FIG. 8 is an explanatory diagram of a sheet stacking portion of a sheet feeding apparatus according to a conventional example.

[Explanation of symbols]

 A: Sheet feeding means 1 ... Storage 2 ... Tray 3 ... Lifting wire 4 ... Winding drum 4a ... Winding shaft 5 ... Drive motor 6 ... Drive transmission gear 7 ... Drive transmission gear 8 ... Drive transmission gear 9 ... Winding shaft Gear 10 Damper mechanism 11 First damper gear 12 Link arm 12a Engagement part 13 Second damper gear 14 Link arm 14a Link groove 14b Stopper locking part 15 Support shaft 16 Stopper 17 Damper mechanism 18 … Damper mechanism 19… Link arm 20… Pickup roller 21… Feed roller 22… Retard roller 23… Convey path 101… Image forming unit 102… Process cartridge 103… Electrophotographic photosensitive drum 104… Charging means 105… Developing means 106… Cleaning means 107: Scanner unit 108: Transfer roller 109: Fixing unit 110: Fixing rollers 111, 112: Sheet cassettes 113, 114: Picker Roller 115, 117… Feed roller 116, 118… Retard roller 119… Discharge tray

Continuing on the front page (72) Inventor: Judge Sekiya 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Yuzo Isoda 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Takashi Kuwata 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc.

Claims (6)

[Claims] 1. loading means for loading sheets to be supplied;
A wire connected to the loading means for raising and lowering the loading means, a winding shaft of the wire, a damping means for attenuating the rotation of the winding shaft, and a driving force transmitting means connected to the winding shaft. And a driving device for applying a driving force to the driving force transmitting means, wherein the stacking means is dropped by separating the driving device and the driving force transmitting means. A rotating body interlocked with the rotation of the winding shaft of the wire; a damping means rotatably connected to the rotating body for applying a damping force; and a damping force generated by a reaction force acting on the damping means from the rotating body. A sheet feeding device provided with damping force switching means for switching damping force of the means. 2. The damping force switching means sets a difference in a reaction force for switching between a state in which the damping force of the damping means is increased and a state in which the damping force is decreased, and increases the reaction force for switching to a state in which the damping force is increased. By reducing the reaction force for switching to the state of decreasing, the state where the damping force switching means switches to the state of increasing the damping force maintains the state of increasing the damping force even if the reaction force is reduced by the damping force. The sheet feeding device according to claim 1, wherein the sheet feeding device is configured to perform the following. 3. The damping means is two damper gears connecting an oil damper and a gear, and the damping force switching means is a damping gear switching means. The sheet feeding device according to claim 1, wherein the sheet feeding device connects and disconnects with a second damper gear. 4. A moving load means is provided on a movement path of said second damper gear by said damping force switching means, and said second damper gear is driven by said damping force switching means with a force necessary for passing said moving load means. 4. The sheet feeding device according to claim 3, wherein a difference in a reaction force for switching is configured. 5. A moving direction of the second damper gear with respect to the rotating body is set at a predetermined angle with respect to a radial direction of the rotating body, and a reaction force received by the second damper gear from the rotating body is equal to the second damper gear. 4. The sheet feeding apparatus according to claim 3, wherein a difference in a reaction force for switching the damping force switching means is configured by acting on the rotating body in a direction of urging the rotating body. 6. A sheet supply apparatus according to claim 1, further comprising: an image forming unit configured to form an image on a sheet sent from the sheet supply apparatus. Image forming device.