JP2003012175A - Paper feeding device and image forming device equipped with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a paper feeding device capable of securely separating/ feeding sheets regard less so the rigidity of the sheets and an image forming device equipped with the same. SOLUTION: Sheets S stored in a sheet storing means 30 are sent out by a sheet feeding means 18, and after that, the sheets S are separated one by one by a separating slope 31 and fed. The sheet storing means 30 is rotatably mounted in the main body 2A of the device, and the angle θ between the sheet storing means 30 and the separating slope 31 is changed according to the rigidity of the sheets S.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet feeding device and an image forming apparatus having the same, and more particularly to a sheet feeding device for separating sheets using a separating slope.

[0002]

2. Description of the Related Art Conventionally, image forming apparatuses such as printers, copying machines, and facsimiles are equipped with a sheet feeding device for feeding sheets to an image forming section. As such a sheet feeding device, for example, GB1155370 (19
66.9.14 filed) FIG. As shown in FIG. 4, a separation slope is provided on the leading end side of a sheet feeding tray for stacking sheets, and the sent-out sheets are abutted against the separation slope to separate the sheets one by one. There is a separation method.

FIG. 10 is a diagram showing the construction of a sheet feeding device of such a slope separation type. In the figure, 14 is a sheet feeding device for sequentially feeding the stacked sheets S, and this sheet feeding device 14 is provided with a sheet feeding tray 30 for stacking the sheets S and a separation slope 31. Paper tray unit 15,
The paper feed unit 16 and the transport unit 17 are provided.

Here, the paper feed section 16 has a paper feed roller 18 which rotates integrally with a gear (not shown), an idler gear A19 which meshes with a gear (not shown) of the paper feed roller 18, an idler gear B20 which meshes with the idler gear A19, and an idler gear B20. A drive gear 21 that meshes with the drive gear 21
Drive shaft 2 mounted to rotate integrally with
2, a paper feed roller 18, an idler gear A19, an idler gear B20, and a drive gear 21 are rotatably supported, and a paper feed roller holder 23 is rotatably attached to a drive shaft 22. The drive shaft 22 is driven by a controllable drive mechanism (not shown), and as a result, the start and stop of the sheet feeding operation are controlled.

Further, the conveying section 17 is provided with the fed sheet S.
Lower guide 24 that guides the lower surface of the sheet S, an upper guide 25 that guides the upper surface of the fed sheet S, and a conveyance roller 26 that conveys the fed sheet S in a predetermined direction.
A rotatable transport roller 27 arranged to face the transport roller 26, a roller holder 28 rotatably supporting the transport roller 27 and rotatably supported by the upper guide 25, and a transport roller 27. It is provided with a conveyance spring 29 for urging the roller holder 28 so as to press it against the conveyance roller 26.

In the sheet feeding device 14 having such a configuration, the feeding operation of the sheet S is performed as follows.

When sheet feeding is started, the drive shaft 22 is driven by a controllable drive mechanism (not shown),
Rotate. Then, this rotation is transmitted to the paper feed roller 18 via the idler gear B20 and the idler gear A19,
The paper feed roller 18 starts rotating.

Here, the paper feed roller holder 23, which holds the paper feed roller 18 rotatably, exerts a force in a counterclockwise direction in the figure by an unillustrated urging means or its own weight. This force causes the paper feed roller 18 to move the sheets placed on the paper feed tray 30 to
It is lightly pressed onto the upper surface of the uppermost sheet S1. As a result, when the paper feed roller 18 starts to rotate,
A feeding force F due to a frictional force acts on the uppermost sheet S1, and the sheet S1 is fed by the feeding force F and abuts against the separation slope 31.

When the sheet S1 hits the separation slope 31 in this manner, the sheet S1 receives the reaction force F from the separation slope 31,
By being bent by the reaction force F, the separation slope 3
1 will be advanced in a bent state with its tip abutting.

After this, the sheet S1 is placed on the upper guide 2
5 and the lower guide 24 determine the direction of travel and enter the nip formed by the conveying roller 27 and the conveying roller 26 that are urged toward the conveying roller 26 by the conveying spring 29, and further move in the direction of arrow A by the conveying roller 26. Be transported to.

[0011]

By the way, in such a conventional sheet feeding device and an image forming apparatus provided with such a sheet feeding device, it is possible to reliably feed a sheet S1 having a small rigidity such as thin paper. When the angle of the separation slope 31 with respect to the paper feed tray 30 (hereinafter referred to as the slope angle) is set to an angle close to a right angle, when a highly rigid sheet such as thick paper is fed, the space between the paper feed roller 18 and the separation slope 31 is increased. so,
A sheet with high rigidity must be bent and separated and fed.

[0012] Here, a large feeding force is required to bend and separate and feed such a sheet having a large rigidity, and when the feeding force is insufficient, a sheet having a large rigidity is used. Since the paper feed roller 18 slips on the upper side, a sheet having high rigidity cannot be separated and fed.

On the other hand, if the slope angle is set gently, it is not necessary to bend a highly rigid sheet to a large extent, and it is possible to reliably feed a highly rigid sheet with a small feeding force.

By the way, when the slope angle is set gently in this way, when feeding a sheet having low rigidity, the sheet is easily bent between the sheet feeding roller 18 and the separating slope 31 to separate and feed. At this time, the sheet immediately below the uppermost sheet S1 receives a very small feeding force due to the frictional force when the uppermost sheet S1 is fed.

When receiving such an extremely small feeding force, if the separating / feeding is possible with the extremely small feeding force, the sheet immediately below the topmost sheet is also separated / feeding, Double feed will occur.

That is, when the slope angle is set so that the sheet having low rigidity can be separated and fed, it becomes difficult to separate and feed the sheet having high rigidity, and the slope angle is set so that the sheet having high rigidity can be separated and fed. If set, there is a problem that double feeding may occur when separating and feeding sheets having low rigidity.

Further, as shown in FIG. 10, the paper feed roller 1
In the case of a configuration in which 8 is rotatably supported by the paper feed roller holder 23 and the paper feed roller holder 23 is rotatably supported with respect to the drive shaft 22, the paper feed tray 30 and the paper feed roller holder 23 form If the angle becomes too large, the paper feed roller 18 bites in the direction in which the sheet is pressed, which causes a problem of paper feed.

Therefore, the present invention has been made in view of the above situation, and a sheet feeding device capable of reliably separating and feeding sheets regardless of the rigidity of the sheet, and an image forming apparatus including the same. The purpose is to provide a device.

[0019]

SUMMARY OF THE INVENTION According to the present invention, a sheet is fed by a sheet feeding means for feeding a sheet stored in a sheet storing means, and a separation slope for separating the sheets fed by the sheet feeding means one by one. In a sheet feeding device that separates and feeds the sheets one by one, the sheet storage means is rotatably provided in the apparatus main body, and the angle formed by the sheet storage means and the separation slope is changed according to the rigidity of the sheet. It is characterized by doing so.

Further, according to the present invention, the sheet storage means is arranged at a first position where the angle formed by the sheet storage means and the separation slope is large when the rigidity of the sheet is high, and when the rigidity of the sheet is low, the separation slope is formed. It is characterized in that each of them is rotated to a second position where the angle formed by is smaller.

Further, according to the present invention, the sheet feeding means is arranged so that the distance between the sheet feeding means and the separation slope becomes long when the sheet storing means is rotated to the first position. It is characterized in that it is provided with a position control means for moving to a position where the distance to the separation slope becomes short when it is rotated to two positions.

The present invention further comprises an arm member for rotatably holding the sheet feeding means, and the arm member serves as the sheet storing means when the sheet storing means moves to the first or second position. It is characterized in that it is configured to move while keeping the angle of.

Further, the present invention comprises a detecting means for detecting the rigidity of the sheet, and a moving means for moving the sheet storing means to the first or second position, which is detected by the detecting means. The sheet storing means is moved to the first or second position by the moving means based on the detection of the rigidity of the sheet.

According to the present invention, the detection means is based on the magnitude of the reaction force received by the sheet feeding means from the separation slope when the sheet feeding means feeds the sheet stored in the sheet storing means. The present invention is characterized in that it is configured to detect the rigidity of the seat.

Further, the present invention is characterized in that the moving means is a cam means.

The present invention is also characterized in that the separation slope is provided rotatably on the apparatus main body.

Further, the present invention is an image forming apparatus comprising an image forming section and a sheet feeding apparatus for feeding a sheet to the image forming section, wherein the sheet feeding apparatus is any one of the above. It is characterized by that.

[0028]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a view showing the schematic arrangement of an image forming apparatus provided with a sheet feeding device according to the first embodiment of the present invention.

In FIG. 1, 1 is an image forming apparatus, 1A is an image forming apparatus main body (hereinafter referred to as an apparatus main body), and the image forming apparatus 1 includes an image forming section 3 for forming an image on a sheet S, A sheet feeding device 2 that feeds a sheet to the image forming unit 3, a fixing device 9 that fixes the image formed on the sheet S in the image forming unit 3, and a sheet S to which the image is fixed.
Ejecting means 4 for ejecting the sheets and sheet stacking means 5 for stacking the ejected sheets S are provided.

Here, the image forming section 3 is a photosensitive drum 7 which is an image carrier having a photosensitive layer on its surface, and a charging means which is a charging means for uniformly charging the surface of the photosensitive drum 7 by applying a voltage. A roller 10, a developing means 11 for developing a latent image formed on the photosensitive drum by exposure by the exposing means 6 with a developer (hereinafter referred to as toner), and a developing means 11.
A transfer roller 8 for transferring the toner image formed on the photosensitive drum 7 to the sheet by the transfer roller 8 and for scraping off the toner remaining on the surface of the photosensitive drum 7 after the toner image is transferred to the sheet by the transfer roller 8. The cleaning means 12 of FIG. In addition, 13 is a photosensitive drum 7,
Charging roller 10, developing unit 11, cleaning unit 12
Is a process cartridge integrally provided with.

Next, the image forming operation of the image forming apparatus 1 thus constructed will be described.

When an image is formed, first, the photosensitive drum 7 is irradiated with an optical image based on the target image information by the exposing means 6 such as slit image forming projection means and laser scanning exposing means, and the latent image is formed on the photosensitive drum. Form an image. Next, this latent image
The developing means 11 develops to form a toner image on the photosensitive drum.

On the other hand, in synchronization with the formation of this toner image, the sheet S is fed from the sheet feeding device 2 to the nip between the photosensitive drum 7 and the transfer roller 8, and the sheet S is fed onto the photosensitive drum. The toner image formed on the above is transferred by the transfer roller 8. Thereafter, the sheet S on which the toner image is transferred is fixed to the fixing rotator 9a and the fixing rotator 9 having a heater (not shown) built therein.
The toner image is conveyed to a fixing device 9 including a driving roller 9b that is in pressure contact with a, and the toner image is fixed on the sheet S. Further, after fixing the toner image in this way, the sheet S is discharged to the sheet stacking unit 5 by the discharging unit 4.

By the way, FIG. 2 is an enlarged view of the sheet feeding device 2. As shown in FIG. 2, the sheet feeding device 2 includes a sheet feeding tray portion 15 having a sheet feeding tray 30 as sheet storing means, and a sheet feeding tray portion 15. The sheet tray 30 includes a feeding unit 16 for sequentially feeding the sheets S stacked on the paper tray 30, and a conveying unit 17.

Here, the feeding unit 16 includes a sheet feeding roller 18 which is a sheet feeding unit that rotates integrally with a gear (not shown),
An idler gear A19 that meshes with a gear (not shown) of the paper feed roller 18, an idler gear B20 that meshes with the idler gear A19, and a drive gear 21 that meshes with the idler gear B20.
And a drive shaft 22 to which the drive gear 21 is attached,
Paper feed roller 18, idler gear A19, idler gear B
20 and a drive gear 21 are rotatably supported, and a paper feed roller holder 23, which is an arm member rotatably attached to a drive shaft 22, is provided. The drive shaft 22 is driven by a controlled drive means (not shown).
It is controlled to drive at the time of separation and feeding.

On the other hand, the conveying section 17 has a lower guide 24 and an upper guide 25 for guiding the lower surface and the upper surface of the sheet S separated and sent out by the feeding section 16, and the sent sheet in a predetermined direction. Transport roller 2 for transport
6 and the conveying roller 2 arranged to face the conveying roller 26.
7 and the transfer roller 27 rotatably supported, and the roller holder 28 rotatably supported by the upper guide 25 via the rotating shaft 28a, and the roller holder 28 for pressing the transfer roller 27 against the transfer roller 26. And a conveying spring 29 that is biased.

The paper feed tray section 15 includes a paper feed tray 30 and a separation slope 31. Here, the paper feed tray 30 is rotatably attached to a frame (hereinafter, referred to as a main body frame) 32 of the paper feed device main body 2A around a rotary shaft 33, and has a snap fit protrusion 30a. is doing.

The main body frame 32 has a paper feed tray 3
The first holding hole 32a that engages with the protruding portion 30a of No. 0 and holds the paper feed tray 30 in the upwardly rotated position (hereinafter referred to as the second position) shown in FIG. Second holding hole 3 for holding at the predetermined position (hereinafter referred to as the first position)
2b is formed.

Then, the projection 30a of the snap fit
By engaging with the holding holes 32a and 32b of the main body frame 32, the paper feed tray 30 can be held at the first position or the second position.

Next, the sheet feeding operation of the sheet feeding device 2 having such a configuration will be described.

When carrying out the paper feeding operation, first, the drive shaft 22 is rotated by a drive mechanism (not shown) which is driven and controlled by a control means (not shown) which controls the start and stop of the paper feeding operation. When the drive shaft 22 rotates in this way, this rotation is transmitted to the paper feed roller 18 via the idler gear B20 and the idler gear A19, and the paper feed roller 18 starts rotating.

Here, the paper feed roller holder 23, which holds the paper feed roller 18 rotatably, exerts a force in a counterclockwise direction in the figure by an urging means (not shown) or its own weight. This force causes the paper feed roller 18 to move the sheets placed on the paper feed tray 30 to
It is lightly pressed onto the upper surface of the uppermost sheet S1. As a result, when the paper feed roller 18 starts rotating,
The feeding force due to the frictional force of the paper feed roller 18 acts on the uppermost sheet S1, and when such a feeding force acts, the uppermost sheet S1 abuts on the separation slope 31 and then the separation slope. It will be able to bend by receiving the reaction force from 31.

By the way, in the present embodiment, when feeding a sheet having low rigidity, the sheet feeding tray 30 is moved to the second position shown in FIG. 2 before starting the sheet feeding operation. . Then, when the paper feed tray 30 is moved to the second position in this way, the angle θ formed by the separation slope 31 and the paper feed tray 30 (hereinafter referred to as the slope angle) becomes sufficiently small.

Here, when the slope angle θ is made sufficiently small in this way, the feeding force necessary for separating and feeding the sheet S becomes larger. As a result, the paper feed tray 30
The sheet S2 immediately below the uppermost sheet S1 stacked on the sheet S is not separated / fed by a very small feeding force due to a frictional force when the uppermost sheet S1 is fed. Disappear. As a result, double feeding can be reliably prevented.

On the other hand, when feeding a highly rigid sheet, the paper feed tray 30 is moved to the first position shown in FIG. When the paper feed tray 30 is moved to the first position in this way, the slope angle θ becomes large, and the feeding force necessary for separating and feeding the highly rigid sheet S becomes small.

As a result, when the sheet S having high rigidity is separated and fed, it is not necessary to bend the sheet S having high rigidity between the paper feed roller 18 and the separation slope 31, and the sheet having high rigidity can be surely obtained. S can be delivered.

As described above, according to the present embodiment, by changing the slope angle θ according to the rigidity of the sheet S, that is, when the sheet S having a low rigidity is fed, the paper feed tray 3
0 to the second position to decrease the slope angle θ, and when feeding the sheet S having high rigidity, the paper feed tray 30 is moved to the first position to increase the slope angle θ, so that the slope angle θ is always appropriate. The sheet S can be separated and fed at the slope angle θ. As a result, the sheet S can be reliably separated and fed regardless of the rigidity of the sheet S, and the sheet feeding performance can be sufficiently satisfied.

Next, a second embodiment of the present invention will be described.

FIG. 4 is a diagram showing the structure of the sheet feeding device according to the present embodiment. In the figure, the same symbols as those in FIG. 2 indicate the same or corresponding parts.

In the figure, 34 is a paper feed tray 30,
The drive side plate 34 is mounted slidably in the sheet feeding direction, and the drive side plate 34 supports the drive shaft 22 and a controlled drive means (not shown). Also, 3
Reference numeral 4a denotes a protrusion formed on the side wall surface of the drive side plate 34. The protrusion 34a is formed inside the side surface of the main body frame 32 and is always engaged with the guide groove 32c which constitutes the position regulating means together with the drive side plate 34. Configured to match.

Here, the guide groove 32c is interlocked with the movement of the sheet feeding tray 30 when the sheet feeding tray 30 is moved from the second position shown in the same drawing to the first position shown in FIG. When the drive side plate 34 is slid in the direction away from the separation slope 31 and is moved from the first position shown in FIG. 5 to the second position shown in FIG. 4, the drive side plate 34 is slid in the direction approaching the separation slope 31. It has various shapes.

The guide groove 32c having such a shape
When the paper feed tray 30 is moved to the first position by engaging the protrusion 34a of the drive side plate 34 with the drive side plate 34, the drive side plate 34 slides in the direction approaching the separation slope 31, and as the drive side plate 34 slides. The paper roller 18 moves to a position near the separation slope 31 shown in FIG. Further, when the paper feed tray 30 is moved to the second position, the drive side plate 34 slides in a direction away from the separation slope 31 and the drive side plate 3 is moved.
The paper feed roller 18 moves to a position away from the separation slope 31 shown in FIG.

That is, in the present embodiment, when the sheet S having low rigidity is fed, as shown in FIG.
When 0 is moved to the second position, the slope angle θ becomes sufficiently small, and the distance X between the paper feed roller 18 and the separation slope 31 becomes X.
Becomes shorter.

Here, the paper feed tray 30 is first
The sheet is moved to the position to make the slope angle θ sufficiently small, and further, the distance X between the paper feed roller 18 and the separation slope 31 is shortened, so that the sheet S having low rigidity is separated and fed. The power becomes even greater. As a result, double feeding can be prevented more reliably.

On the other hand, when the sheet S having high rigidity is fed, if the sheet feeding tray 30 is moved to the first position as shown in FIG. 5, the slope angle θ becomes large and the sheet feeding roller 18 separates the separation slope 31. To get away from.

Here, when the sheet S having high rigidity is fed, the sheet feeding tray 30 is moved to the first position in this way to increase the slope angle θ, and the sheet feeding roller 18 and the separation slope 31 are further separated. By increasing the distance X, the sheet S can be separated and fed without being greatly bent. As a result, the feeding force required when separating and feeding the sheet S having high rigidity is considerably reduced, so that the sheet S having high rigidity can be fed more reliably.

As described above, according to the present embodiment, by changing the slope angle θ and the distance X between the sheet feeding roller 18 and the separation slope 31 in accordance with the rigidity of the sheet S, that is, the sheet S having low rigidity is obtained. When feeding, the slope angle θ is reduced and the distance X between the paper feed roller 18 and the separation slope 31 is shortened.
When the sheet S having high rigidity is fed, the slope angle θ is increased and the distance X between the paper feed roller 18 and the separation slope 31 is increased so that the slope angle θ is always appropriate and the paper feed roller 18 is appropriate. The sheet can be separated and fed at the distance X of the separation slope 31. As a result, the sheet S can be reliably separated and fed regardless of the rigidity of the sheet S, and the sheet feeding performance can be sufficiently satisfied.

Next, a third embodiment of the present invention will be described.

FIG. 6 is a diagram showing the structure of the sheet feeding device according to the present embodiment. In the figure, the same reference numerals as those in FIG. 2 indicate the same or corresponding parts.

In the figure, reference numeral 40 denotes a side plate fixed to the paper feed tray 30, and the side plate 40 supports a drive shaft 22 and a controlled drive means (not shown). Here, for example, when feeding a sheet having high rigidity as described above, the paper feed tray 30 is moved to the first position as shown in FIG. 7, but the paper feed tray 30 is moved to the first position in this way. Since the drive shaft 22 is integrally attached to the side plate 40 of the paper feed tray 30 even when moved to, the angle θ ′ formed by the paper feed roller holder 23 and the paper feed tray 30 (hereinafter referred to as the roller holder angle) is Holds constant.

Then, the paper feed tray 30 is set to the first
By keeping the roller holder angle θ ′ constant even when the paper feed tray 30 is moved to the position, in other words, even when the paper feed tray 30 is moved to the first position, the paper feed tray 30
By configuring so that the angle formed by the sheet feeding roller holder 23 and the sheet feeding roller holder 23 does not become large, it is possible to prevent the sheet feeding roller 18 from biting into the sheet and causing a sheet feeding failure.

As described above, by keeping the roller holder angle θ'constant even when the paper feed tray 30 is moved to the first position as in the present embodiment, the slope angle is always appropriate, and The sheet can be separated and fed at an appropriate roller holder angle where the sheet feeding roller 18 does not bite into the sheet. As a result, the sheets can be reliably separated and fed, and the sheet feeding performance can be sufficiently satisfied.

Next, a fourth embodiment of the present invention will be described.

FIG. 8 is a diagram showing the structure of the sheet feeding device according to the present embodiment. In the figure, the same symbols as those in FIG. 2 indicate the same or corresponding parts.

In the figure, reference numeral 35 is a paper feed roller holder 2.
3 is a contact plate rotatably provided on the shaft 3 via a shaft 36a, and the contact plate 35 is in contact with the drive shaft 22. Further, reference numeral 36 is a load cell which is a detecting means for contacting the surface of the contact plate 35 on the side opposite to the surface contacting the drive shaft 22, and the load cell 36, as will be described later, when the sheet is fed, The contact force when the contact plate 35 is pressed against the drive shaft 22 is detected.

Reference numeral 23a is a support hole formed in the paper feed roller holder 23 and into which the drive shaft 22 is inserted. The support hole 23a has an elongated hole shape toward the paper feed roller 18. As a result, the paper feed roller holder 23 can be loosely abutted or pressed against the drive shaft 22 via the abutment plate 35, and the load cell 36 can be abutted on the abutment plate 35.
The force with which the paper feed roller holder 23 pushes the drive shaft 22 can be detected via the.

Further, in the figure, 37 is the paper feed tray 3
0 is a paper feed tray cam which is a cam means which is an example of a moving means arranged below 0. The paper feed tray cam 37 is driven by a controlled driving means (not shown) and is integrated with a rotating paper feed tray cam shaft 38. It is designed to rotate.

By the way, the controlled drive means is controlled to rotate the paper feed tray cam shaft 38 by 180 ° when the load cell 36 detects a force larger than a predetermined value. Here, the paper feed tray cam shaft 38 is 180
When rotated, the paper feed tray 30 moves from the second position shown in the figure to the first position shown in FIG. 9 due to its own weight and the load of the sheet S. When the controlled driving means detects that the feeding of the sheet is completed by a sensor or the like (not shown), the feeding tray cam shaft 38 is further rotated by 180 ° to return the feeding tray cam 37 to the original position. Controlled by.

Next, the feeding operation of the sheet feeding device having such a configuration will be described.

When the feeding operation is started, the paper feed roller 18
When the sheet feed roller 18 pushes the sheet S stacked on the sheet feed tray 30 in the transport direction, the sheet feed roller 18 receives the reaction force from the separation slope 31 via the sheet S. The paper feed roller holder 23 is pushed, so that the paper feed roller holder 23 pushes the drive shaft 22.

Here, when the sheet S has a small rigidity, the sheet S is separated and fed with a small feeding force.
The force by which the feed roller holder 23 pushes the drive shaft 22 is small,
The force detected by the load cell 36 is smaller than a predetermined value.
Therefore, the sheet S is fed without driving the paper feed tray cam shaft 38.

On the other hand, in the case where the sheet S has a high rigidity, the feeding force required for separating and feeding the sheet S is large, so that the sheet feeding roller holder 23 also pushes the drive shaft 22 with a large force. As a result, the force detected by the load cell 36 becomes larger than a predetermined value, and as a result, the paper feed tray cam shaft 38 is driven to rotate 180 °.

Then, as described above, the paper feed tray cam shaft 38
Is rotated by 180 °, the paper feed tray cam 37 is positioned as shown in FIG. 9, and the paper feed tray 30 moves to the first position where the slope angle θ increases due to its own weight. As a result, the feeding force required to separate and feed the highly rigid sheet S is reduced. When the feeding is completed, the paper feed tray cam shaft 38 is driven again to rotate 180 °, and the paper feed tray 30 returns to the original position.

As described above, the load cell 36 detects the rigidity of the sheet S, and the sheet feeding tray 30 is moved to the first or second position according to the result, so that the sheet is always kept at an appropriate slope angle θ. S can be separated and fed. As a result, the sheet S can be reliably separated and fed, and the sheet feeding performance can be sufficiently satisfied.

Further, as in the present embodiment, by rotating the paper feed tray 30 according to the value of the load cell 36 to automatically switch the slope angle θ, the sheet fed by the user has high rigidity. There is no need to judge whether it is a seat or a sheet with low rigidity, and there is no hassle. Further, it is possible to perform a reliable switching without making an erroneous judgment and making an operation mistake.

In the above description, the structure in which only the paper feed tray 30 is rotated has been described.
The present invention is not limited to this, and the separation slope 31 may be rotatable. By making the separation slope 31 rotatable in this way, the slope angle θ can be set more finely according to the rigidity of the sheet, and the sheet S can be separated and fed more reliably. Like

[0078]

As described above, as in the present invention, the sheet accommodating means is rotatably provided on the main body of the apparatus, and the angle formed by the sheet accommodating means and the separation slope is changed according to the rigidity of the sheet. By doing so, the sheets can be reliably separated and fed regardless of the rigidity of the sheets.

[Brief description of drawings]

FIG. 1 is a diagram showing a schematic configuration of an image forming apparatus including a sheet feeding device according to a first embodiment of the invention.

FIG. 2 is an enlarged view of the paper feeding device.

FIG. 3 is a diagram showing a state in which a sheet feeding tray of the sheet feeding device is moved to a first position.

FIG. 4 is a diagram showing a configuration of a sheet feeding device according to a second embodiment of the invention.

FIG. 5 is a diagram showing a state in which the sheet feeding tray of the sheet feeding device is moved to a first position.

FIG. 6 is a diagram showing a configuration of a paper feeding device according to a third embodiment of the invention.

FIG. 7 is a diagram showing a state in which the sheet feeding tray of the sheet feeding device is moved to a first position.

FIG. 8 is a diagram showing a configuration of a paper feeding device according to a fourth embodiment of the invention.

FIG. 9 is a diagram showing a state in which the sheet feeding tray of the sheet feeding device is moved to a first position.

FIG. 10 is a diagram showing a configuration of a conventional paper feeding device.

[Explanation of symbols]

1 Image forming device 2 Paper feeder 2A Paper feeder body 3 Image forming section 18 Paper feed roller 22 Drive shaft 23 Paper feed roller holder 30 paper trays 31 Separation slope 32 paper trays 32a, 32b holding holes 32c guide groove 33 Paper tray rotation axis 34 Drive side plate 36 load cell 37 Paper feed tray cam 40 side plate S sheet θ Slope angle θ'Roller holder angle

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Masayuki Fukuda             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation F-term (reference) 2H072 AB07 BA03 BB04 CA01 CA02                       FA01                 3F048 AA01 AB01 BA06 BB02 BD07                       DA04 DC00 EB06 EB16                 3F343 FA02 FB02 FC14 GA02 GB01                       GC01 GD04 HD09 HD17 KB03                       KB18 LA04 LA16 LD26 MA03                       MA21

Claims (9)

[Claims] 1. A sheet feeding unit that feeds a sheet stored in a sheet storing unit and a sheet feeding unit that feeds the sheet stored in the sheet storing unit, and a separation slope that separates the sheet delivered by the sheet feeding unit one by one. In the sheet feeding device for feeding, the sheet storage means is rotatably provided in the apparatus main body, and the angle formed by the sheet storage means and the separation slope is changed according to the rigidity of the sheet. Paper feeder. 2. The sheet storage means is located at a first position where the angle formed by the sheet storage means and the separation slope is large when the rigidity of the sheet is high, and the angle formed by the separation slope when the rigidity of the sheet is small. 2. The paper feeding device according to claim 1, wherein the paper feeding device is rotated to a second position having a smaller size. 3. The sheet storage means is located at a position where the distance between the sheet storage means and the separation slope becomes longer when the sheet storage means is rotated to the first position.
The sheet feeding device according to claim 2, further comprising a position control unit that moves the position to a position where the distance to the separation slope becomes short when the position is turned. 4. An arm member for rotatably holding the sheet feeding means, wherein when the sheet storing means moves to the first or second position, the arm member forms an angle with the sheet storing means. The sheet feeding device according to claim 1 or 2, wherein the sheet feeding device is configured to move while being kept constant. 5. A detecting means for detecting the rigidity of the sheet, and a moving means for moving the sheet storing means to the first or second position, wherein the sheet detected by the detecting means The sheet feeding device according to claim 1, wherein the sheet storage unit is moved to the first or second position by the moving unit based on detection of rigidity. 6. The detecting unit detects the sheet based on the magnitude of the reaction force received from the separation slope by the sheet feeding unit when the sheet feeding unit feeds the sheet stored in the sheet storing unit. The sheet feeding device according to claim 5, wherein the sheet feeding device is configured to detect rigidity. 7. The sheet feeding device according to claim 5, wherein the moving unit is a cam unit. 8. The sheet feeding device according to claim 1, wherein the separation slope is provided rotatably on the apparatus main body. 9. An image forming apparatus comprising an image forming unit and a paper feeding device for feeding a sheet to the image forming unit, wherein the paper feeding device is any one of claims 1 to 8. An image forming apparatus, which is a sheet feeding device.