JP2000289875A - Sheet feeding device and picture image formation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet feeding device of a slant surface separation type capable of certainly separating and feeding a sheet without being restricted by thickness and rigidity of the sheet and a curled state of a sheet head end. SOLUTION: This device is provided with a separation roller 6 to make contact with a head end upper surface of a sheet free to move between a feeding roller 3 and a separation slant surface 2a and prevents overlapped delivery of the sheet by certainly handling the sheet by bending and separating the sheet between a separation slant surface 2a and the separation roller 6 at a large angle in case of the sheet low in rigidity. It is possible to prevent delivery failure by bending and separating the sheet at a large angle between the separation slant surface 2a and the feeding roller 3 by pushing up the separation roller 6 by rigidity of the sheet in the case of the sheet high in rigidity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet feeding apparatus used for an image forming apparatus for forming an image on a sheet and for separating and feeding stacked sheets one by one.

[0002]

2. Description of the Related Art Conventionally, as a sheet feeding apparatus used in an image forming apparatus such as a printer or a copying machine, there is a so-called slope separation type in which separation is performed using a separation slope. In the sheet feeding apparatus of this separation type, the stacked sheets are sent out by a sheet feeding roller and abutted against a separation slope to separate and separate the sheets one by one.

[0003] In this sheet feeding apparatus of the slope separation type,
No complicated separating means such as a separation pad and a reverse roller is required, and no mechanism such as a lifter mechanism or a spring-biased pressure plate for maintaining the sheet at a predetermined height is required. There is an advantage that the configuration of the feeding device can be simplified.

[0004]

However, in the sheet feeding apparatus of the slope separation type, sheets of relatively various thicknesses and different stiffnesses can be separated and fed, but very thin sheets and small stiffness are provided. In the case of a sheet, since the sheet is easily bent, the sheet is not sufficiently separated when the sheet hits the separation slope, so that double feeding is likely to occur. Therefore, it is conceivable to prevent the double feeding by arranging the position of the sheet feeding roller near the separation slope to largely bend the sheet between the separation slope and the sheet feeding roller to increase the sheet separating force. However, in the case of a very thick sheet or a sheet having a high rigidity, there is a problem in that the sheet is hard to bend and stops when the sheet abuts on the separation slope to cause a feeding failure.

[0005] Further, when the leading edge of a stacked sheet is curled, double feeding or defective feeding may occur.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has been made in consideration of the above-described problems, and is directed to a slope separation system capable of separating and feeding sheets without being restricted by the thickness and rigidity of the sheet and the curl state of the sheet tip. It is an object to provide a sheet feeding device.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a sheet supporting means for stacking and supporting sheets, and a sheet feeder which feeds the sheet in contact with an upper surface of the sheet supported by the sheet supporting means. In a sheet feeding apparatus including a roller and a separation slope for separating a sheet sent out by the sheet feeding roller, a rotatable separation pressing a sheet upper surface is provided between the separation slope and the sheet feeding roller. Rollers are arranged, and roller supporting means for movably supporting the separation rollers according to the rigidity of the sheet to be fed is provided.

Further, according to the present invention, when a sheet to be separated and fed is a sheet having low rigidity, the sheet is separated from the separation roller when the sheet is fed by the paper feed roller and fed along the separation slope. In the case of a sheet having a large rigidity that is bent from the contact point as a base point, the separation roller is pushed up by the sheet, and the separation roller is supported by the supporting means so that the sheet is bent from the contact point with the paper feed roller. Characterized by being supported by

[0009] The present invention is also directed to a separation roller, wherein the separation roller is disposed at a position shifted from the separation slope in the width direction of the sheet supported by the sheet support means, and a part of the outer periphery of the separation roller is separated from the separation slope. It is characterized in that it enters the side where no sheet is loaded.

Further, according to the present invention, the paper feed roller is provided on a paper feed roller arm rotatably held by a roller arm shaft, and the supporting means rotatably supports the separation roller, The sheet feeding device according to any one of claims 1 to 3, further comprising a roller holder rotatably held by the roller.

Further, the present invention is characterized in that a rotation support shaft of the roller holder is the roller arm shaft.

Further, the present invention is characterized in that a rotation support shaft of the roller holder is provided on the roller arm.

Further, the present invention is characterized in that the paper feed roller is arranged at a position facing the separation slope, and the separation roller is arranged at a position not opposed to the separation slope on both sides in the sheet width direction of the separation slope. Features.

The present invention is also directed to a sheet supporting means for stacking and supporting sheets, a sheet feeding roller for abutting on the upper surface of the sheet supported by the sheet supporting means and feeding the sheet, and a sheet fed by the sheet feeding roller. And a separation slope for separating the sheet, a rotatable separation roller urged toward both the sheet upper surface and the separation slope is disposed between the separation slope and the sheet feeding roller. Roller supporting means for movably supporting the separation rollers according to the rigidity of the sheet to be fed is provided.

Further, when the sheet to be separated and fed is a sheet having low rigidity, the sheet is separated from the separation roller when the sheet is fed by the paper feed roller and fed along the separation slope. In the case of a sheet having a large rigidity that is bent with the contact point as a base point, the separation roller is supported by the roller so that the separation roller is pushed up by the sheet and the sheet is bent with the contact point with the paper feed roller as a base point. It is characterized by being supported by means.

Further, according to the present invention, the separation rollers are movably supported on left and right side walls provided on the sheet support means, at openings extending along the separation slope, and the separation rollers are supported. A spring for biasing both the separation slope and the upper surface of the sheet is provided.

Further, the invention is characterized in that it has a release mechanism for separating the paper feed roller and the separation roller from the sheet supported by the sheet support means. Further, in the invention, it is preferable that the release mechanism has a link mechanism interlocked with an operation of an operation means.

Further, according to the present invention, the operating means is a cover which covers the sheet supported by the sheet supporting means and is provided so as to be openable and closable so as to replenish the sheet with the sheet supporting means. The paper feed roller and the separation roller are separated from a sheet by opening a cover.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) FIG. 1 is a view best showing the features of the present invention. FIG. 1 is a sectional view of a sheet feeding apparatus embodying the present invention in a state of waiting for sheet feeding. Is shown.

In FIG. 1, reference numeral 1 denotes a sheet supporting member as a sheet supporting means, 1a denotes a sheet stacking surface of the sheet supporting member 1, and 2 denotes an uppermost sheet bundle from the sheet bundle S stacked on the sheet stacking surface 1a. A slope separating member having a separation slope 2a for separating one sheet S1, a feed roller 3 for feeding the sheet stacked on the sheet stacking surface 1a and coming into contact with the sheet, and a driving roller 4 for driving the sheet feeding roller Is a feed roller arm (L) that holds the feed roller 3 and is rotatably held with respect to the drive shaft 4.

Reference numeral 6 denotes a separation roller (L) that contacts the leading end of the stacked sheet bundle, and 7 denotes a separation roller (L) 6.
Roller arm (L) which rotatably holds the roller and constitutes roller support means rotatably held with respect to the drive shaft 4.
It is. Reference numeral 8 denotes a lower guide that guides the sheet that has passed through the separation slope 2a of the slope separation member 2, reference numeral 9 denotes an upper guide that guides the upper surface of the sheet, and reference numeral 10 denotes a conveyance roller that rotates in the direction of the arrow in FIG. 11 is rotatably held,
This is a transport roller pressed against the transport roller 10 by an urging means (not shown).

FIG. 2 is a view as seen from the direction of arrow A in FIG. 1. In FIG. 2, reference numeral 3a denotes a roller drive gear provided integrally with the paper feed roller 3. Reference numeral 12 denotes a paper feed roller arm (R), which is a member having the same outer shape and hole positional relationship as the paper feed roller arm (L) 5, but rotating the shafts of the gears Ga, Gb, and Gc of the idler gear train. Holding as possible. Reference numeral 13 denotes a drive gear fixed to the drive shaft 4, which meshes with the idler gear Gc in this figure. 14
Is a separating roller (R), 15 is a separating roller arm (R) constituting roller supporting means, both of which have the same shape and mounting structure as the separating roller (L) 6 and the separating roller arm (L) 7. It has become.

The paper feeding operation in the above configuration will be described.

A drive force is transmitted from a drive source such as a motor (not shown) to the drive shaft 4 by a drive control mechanism (not shown), and the drive shaft 4 starts rotating. The rotation of the drive shaft 4 drives the drive gear 13 and the idler gears Ga, Gb, and Gc. Roller drive gear 3a
And the paper feed roller 3 rotates. The uppermost sheet S1 of the sheets S supported by the sheet support member 1 tends to move due to the frictional force due to the rotation of the sheet feeding roller 3, but the separation slope 2a for stopping the movement causes
The sheet S1 receives a reaction force against the frictional force, and the sheet S1 is deformed (= buckling phenomenon) by the reaction force.

At this time, since the sheet S1 is pressed by the separating roller (L) 6 and the separating roller (R) 14, if the sheet S1 is a thin rigid paper type such as thin paper, the separating roller 6, 1 is used.
Deformation starts from the contact point with No. 4. At this time, the separation rollers 6 and 14 may be slightly lifted depending on the rigidity of the sheet, but the starting point of deformation is the separation rollers 6 and 14. In this way, a sheet having a small rigidity is bent at a large angle between the separation slope 2a and the separation rollers 6 and 14, and the fed sheet presses and separates the next sheet between the separation slope 2a, so that the sheet is surely separated. Can be separated.

Thereafter, since the separation rollers 6 and 14 rotate smoothly, the sheet S1 is fed while the base point of sheet bending is in contact with the separation roller, and the nip between the conveyance roller 10 and the conveyance roller 11 is fed. To reach.

When separating thick paper having high rigidity,
As shown by the one-dot chain line in FIG. 1, the separation rollers 6 and 14 and the separation roller arms 7 and 15 are pushed up by the sheet, and are not based on the contact portions with the separation rollers 6 and 14 but on the basis of the contact portion with the sheet feeding roller 3. Deformation occurs. Then, the sheet S <b> 1 is fed while the separation rollers 6 and 14 are lifted, and is sent to the nip between the transport roller 10 and the transport roller 11. As described above, a sheet having a large rigidity is pushed up by the separation rollers 6 and 14 and is bent at a small angle between the separation slope 2 a and the sheet feeding roller 3. That is, since the sheet is not bent at a sharp angle at the position of the separation rollers 6 and 14 but is bent at a gentle angle like a sheet having a small rigidity, the sheet is not stopped in a state where it hits the separation slope 2a. Transmission failure is prevented.

In the configuration of the paper feed roller 3 and the paper feed roller arms 5 and 11 in the present embodiment, the reaction force of the frictional force applied to the sheet by the paper feed roller 3 is increased by the paper feed roller arms 5 and 11.
, And urges the paper feed roller 3 in the direction of pressing against the sheet, the force of the paper feed roller 3 pressing against the sheet S1 automatically increases, and as a result, the paper feed roller 3 The sheet S1 is pushed toward the separation slope 2a, and the sheet feeding force also increases.

Therefore, even when thick paper is fed, it is possible to feed the sheet S1 to the nip portion of the transport roller 9 and the transport roller 10 while pushing up the separation rollers 6, 14. Thereafter, the conveying force of the conveying roller pairs 10 and 11 is applied to the sheet S1, and the sheet S1 is sent to the image forming unit.

With the above configuration, the following effects can be obtained.

A sheet having a small rigidity can be reliably separated and fed without being double-fed, and a sheet having a large rigidity can be reliably separated and fed without causing a feeding failure.

Further, since the member for pressing the upper surface of the leading end of the sheet is a rotatable roller, the resistance for stopping the movement of the sheet can be minimized. Similarly, there is no scratch on the sheet surface. The contact point of the member pressing the upper surface of the sheet can be made closer to the separation slope, and the effect of preventing double feeding can be improved.

In this embodiment, the paper feed roller 3 and the separation rollers (L) 6 and (R) 14 are pressed against the sheet bundle by the weight of the unit, but these are provided with a torsion coil spring or the like. The same effect can be obtained by being urged in the direction of the sheet bundle by the urging means, or urged upwardly to have a contact pressure lighter than its own weight.

Further, in this embodiment, three idler gears are used, and when the drive is transmitted from the drive shaft, a moment in the direction in which the sheet feeding roller 3 is separated from the sheet is generated. By using a single sheet, a moment may be generated in the direction in which the sheet feed roller 3 is pressed against the sheet during drive transmission.

(Second Embodiment) FIGS. 3 and 4 show a second embodiment of the present invention.
The same reference numerals as those in the first embodiment denote equivalent members.
In the figure, 21 is a separation roller (L), 22 is a separation roller arm (L), 23 is a separation roller (R), and 24 is a separation roller arm (R).

The feature of this embodiment is that, as shown in the sectional view of FIG. 3 and the view seen from the direction B in FIG. 3 of FIG. The point is that it enters the opposite side to the sheet feeding roller 3 by a dimension d from the plane stretched by the contact surface 2a. This is because, as shown in FIG. 4, the separation rollers 21 and 23 are arranged outside the slope separation member 2 in the width direction of the stacked sheets, so that even if the separation roller arm is actually rotated, the separation slope 2
a does not interfere with the separation rollers 21 and 23.

In the sheet feeding operation with thick paper in the above configuration, the separation rollers 21 and 23 are pushed up by the sheet.
This is almost the same as the embodiment. When thin paper is fed, as shown in FIG.
By entering below 1, 23, buckling / deformation in a two-dimensional plane (sheet feeding direction and sheet width direction) is caused instead of the one-end fixed and the other end free buckling in the first embodiment. appear. Since a higher force is required to cause this deformation, a corresponding force is applied to the uppermost sheet S1 from the sheet feeding roller 3, but only a weak frictional force between the sheets is applied to the sheet below the sheet S1. Because it does not work, it does not lead to this deformation. Therefore, double feeding with a sheet having lower rigidity than in the first embodiment is further unlikely to occur.

The advantages inherent in the second embodiment are as follows.

It is possible to more strongly prevent double feeding of thin paper. Since the abutting portion that presses the sheet is a rotatable separation roller, the back tension during conveyance can be reduced.
The resistance load in performing thick paper feeding is small, and thick paper can be handled.

(Third Embodiment) FIG. 5 shows a third embodiment of the present invention.
In the figure, the same reference numerals as those in the first embodiment denote the same members.
In the figure, reference numeral 31 denotes a slope separation member having a separation slope 31a, which is installed so as to form an angle of θ2 (> θ1) with the surface of the sheet S. 32 is a separation roller, 33
Reference numeral denotes a separation roller arm, and reference numeral 34 denotes a support shaft that rotatably holds the separation roller arm. Note that a pair of separation rollers is provided as in the first and second embodiments.

In this embodiment, the sheet feeding operation is performed in the same manner, but the angle θ2 of the separation slope 31a with respect to the sheet surface is larger than the angle θ1 in the first and second embodiments. Thicker paper is easier to feed, and thin paper is easier to double feed. However, in the present embodiment, since the separation rollers 32 are arranged, double feeding can be prevented.

The specific effects of the present embodiment are as follows. In order to feed thick rigid paper, it is effective to increase the angle between the separation slope 31a and the sheet stacking surface as in the present embodiment. In this case, since the position of the rotation shaft 4 of the feed roller arm 5 is restricted by the friction coefficient of rubber, if the rotation shaft 4 is used as the support shaft of the separation roller arm 5, the positional relationship between the separation roller 32 and the separation slope 31a is set. Varies greatly depending on the stacking height of the sheet bundle, which is not preferable. By setting the position of the support shaft 33a of the separation roller arm 33 at a position corresponding to the separation slope angle as in the present embodiment, it is possible to set the optimum rotation center / length of the separation roller arm 33. Further, it is possible to reduce the load applied to the rotation shaft for driving the paper feed roller 3.

(Fourth Embodiment) FIG. 6 and FIG.
It is a figure showing a 4th embodiment of the present invention, and the same numerals in the same figure as a 1st embodiment represent the same member. In the figure, 41 is a paper feed roller arm, 42 is a shaft provided on the paper feed roller arm 41, 43 is a separation roller, and 44 is rotatably held at one end by a shaft 42, Further, it is a separation roller arm holding a separation roller 43 at multiple ends. Paper feed roller arm 41, shaft 4
2. The separation roller 43 and the separation roller arm 44 are not shown in the drawing, but are symmetrically arranged in another pair.

FIG. 6 shows a state before the sheet feeding operation, and FIG. 7 shows a state after the start of the sheet feeding operation. The hatched surface in FIG. 7 shows a state in which the sheet S1 is bent in the width direction. Note that the sheet feeding operation in the present embodiment is performed in the same manner as in the second embodiment, and a description thereof will be omitted.

The specific effects of this embodiment are as follows.

The separation rollers 43 can be arranged at substantially the same position with respect to the separation slope regardless of the sheet stacking amount. Since the angle of the separation roller arm does not change much with the change in the stacking amount of sheets, even if the separation roller is urged to the sheet side by using an urging means such as a spring, the fluctuation width of the contact pressure can be reduced. .

(Fifth Embodiment) FIGS. 8 to 11 show a fifth embodiment of the present invention. The features of this embodiment are as follows: (1) No separation roller holder is used. And (2) having a release mechanism for separating the separation roller and the paper feed roller from the sheet.

FIG. 8 shows a state in which the sheet feeding apparatus of this embodiment can feed paper, and FIG. 9 shows a state of the release mechanism in the state of FIG. FIG. 10 is a diagram showing a state in which the release mechanism moves the separation roller and the paper feed roller arm upward to release the nip with the sheet when the cover of the paper feed tray is opened to replenish the sheets. 11
11 is a diagram showing a state of the release mechanism in the state of FIG. In the above drawings, the same reference numerals as those in the first embodiment represent the same members.

8 and 9, reference numeral 51 denotes a sheet feed roller arm, and 52, a separation roller. The separation roller 52 extends in the width direction of the sheet feeding device in the present embodiment. And extends outside the inner wall surface (side wall) 1b at both ends, and its protruding portion is indicated by 52a. Reference numeral 53 denotes an opening formed in the inner wall surface 1b through which the protruding portion 52a passes, and the opening 53 is formed in an elongated hole along the separation slope 2a.

Reference numeral 54 denotes a cover for protecting the upper surface of the sheet bundle S which has come out of the outer frame 61 of the image forming apparatus main body.
4a is a gear member fixed to the cover 54. 54b
Is a rotation support shaft of the cover 54. 55 is a side regulating member that determines the position of the side end of the sheet bundle S, and 56 is a gear arm that is supported by the drive shaft 4.

Reference numeral 56a denotes a gear portion engaged with the gear member 54a, and 56b denotes an arm portion forming a link.
The two are formed integrally or fixed to each other. 57 is a rod having link nodes N1 and N2 at both ends, and 58 is one end having N3 at the sheet feeding device frame or the like.
And the other end is rotatably connected to the rod 57 and the node N2 so as to be rotatable.
Reference numeral 9 denotes a tension spring that pulls the separation roller 52 in the lower left direction in the drawing, that is, the direction in which both the separation slope 2a of the slope separation member 2 and the sheet bundle S are pressed.
The other end is held by the support shaft 60 at 2a.

The paper feeding operation according to the above configuration is the same as that of the first embodiment, and the description is omitted.

Next, the operation of the release mechanism when replenishing the sheet bundle S will be described. During the paper feeding operation standby or during the paper feeding operation, the release mechanism is in the state shown in FIG. The member 2 is in contact with the separation slope 2a.

A cover 5 for the user to replenish sheets.
8 is rotated counterclockwise in FIG. 8, the gear member 54a integrated with the cover 54 rotates, and accordingly, the gear portion 56a of the gear arm 56 engaged with the gear member 54a.
1 also rotates, and the four-bar linkage including the arm portion 56b, the rod 57, and the separation roller releasing arm 58 operates to operate as shown in FIG.
1 is reached. At this time, as shown in FIG. 10, the sheet supply roller arm 51 and the separation roller 52 are avoided to a position higher than the stackable height of the sheet bundle, and the user can easily supply the sheet bundle.

The specific effects of this embodiment are as follows.

Since the movable range of the separation roller 52 can be freely set, it is possible to set an optimum gap with respect to the separation slope in accordance with the load amount, so that more stable sheet feeding performance can be realized. It becomes possible. Since the separation roller 52 that is in contact with both the separation slope 2a and the sheet bundle can be installed, the outer diameter of the separation roller 52 is reduced, the tip curvature at the time of feeding thin paper is reduced, and there is a stronger double feed prevention force. A separation slope separation sheet feeding device can be realized.

In the present embodiment, the sheet supply roller and the separation roller are separated from the upper surface of the sheet by opening the cover when replenishing the sheet. However, the operation is performed by operating the operation lever or the like. You may do it. Also,
The sheet support member is a cassette that can be attached to and detached from the main unit,
The paper feed roller and the separation roller may be separated from the upper surface of the sheet with the release of the lock means for restricting the drawer of the cassette.

The features of the above embodiments are not limited to the embodiments, and the features of the embodiments can be combined as appropriate.

Next, an example of an image forming apparatus (laser beam printer) using the sheet feeding apparatus of the present invention will be described with reference to FIG.

FIG. 12 shows a sheet feeding apparatus to which the present invention is applied. A configuration for forming an image on a sheet sent from the sheet feeding device will be described. Reference numeral 108 denotes a toner cartridge, 109 denotes a photosensitive drum held by the toner cartridge 108,
Reference numeral 110 denotes a laser scanner that forms a latent image on the photosensitive drum 109; and 111, a transfer roller that transfers a toner image formed by developing the latent image formed on the photosensitive drum 109 in the toner cartridge 108 to a sheet side. , 1
A fixing device 12 fixes the toner image on the sheet.

Reference numeral 113 denotes a paper discharge roller pair for conveying the sheet after fixing, reference numeral 114 denotes a paper discharge roller for discharging the sheet outside the image forming apparatus, and reference numeral 115 denotes a paper discharge tray for stacking the discharged sheets.

According to the above configuration, the sheet feeding roller 103 is in pressure contact with the uppermost surface of the sheet bundle S placed on the sheet stacking surface.
A feeding force due to a frictional force acts on the uppermost sheet, and the sheet is separated and fed between the separation slope 2 and the sheet feeding roller 3 in a bent state.

The separated and fed sheet is transported by a pair of transport rollers 1.
The developing drum 10 is further transported by the rotation of
9 and the nip between the transfer roller 111. The latent image written on the developing drum 109 by the scanner 110 is developed in the toner cartridge 108 and is transferred to a sheet by the transfer roller 111. Fixing device 112
The toner transferred to the sheet is fixed to the sheet, and the sheet after fixing is discharged to the discharge roller pair 113 and the discharge roller 1.
14, the sheet is discharged out of the image forming apparatus,
15 is loaded.

Although the embodiment of the present invention has been described in detail, the present invention is not limited to this. For example, in the present embodiment, sheets are stacked and supported in a state where the sheet stacking surface is horizontal.However, the sheet stacking surface is inclined to provide a separation slope on the lower side, and the sheet is separated from the lower side. You may make it feed. Further, the sheet stacking surface and the separation slope may be provided in a cassette that is detachable from the apparatus main body.

[0065]

As described above, according to the present invention,
In the sheet feeding apparatus using the separation slope separation, it is possible to enhance the prevention of double-feeding of a sheet having a small rigidity and to prevent the defective feeding of a sheet having a high rigidity. Accordingly, it is possible to provide a sheet feeding apparatus capable of reliably performing separation and feeding without being affected by the rigidity of the sheet under a simpler configuration.

[Brief description of the drawings]

FIG. 1 is a main sectional view of a sheet feeding apparatus according to a first embodiment of the present invention;

FIG. 2 is a view of the sheet feeding apparatus in FIG.

FIG. 3 is a main sectional view of a sheet feeding device according to a second embodiment of the present invention;

FIG. 4 is a view of the sheet feeding device in FIG.

FIG. 5 is a main sectional view of a sheet feeding apparatus according to a third embodiment of the present invention;

FIG. 6 is a main cross-sectional view of a sheet feeding apparatus according to a fourth embodiment of the present invention in a sheet feeding standby state.

FIG. 7 is a main cross-sectional view of a sheet feeding device according to a fourth embodiment of the present invention during a sheet feeding operation;

FIG. 8 is a main cross-sectional view of a sheet feeding apparatus according to a fifth embodiment of the present invention during standby for sheet feeding;

FIG. 9 is a diagram illustrating a state in which a separation cam release mechanism of a sheet feeding device according to a fifth embodiment of the present invention is in a sheet feeding standby state.

FIG. 10 is a main cross-sectional view of a sheet feeding apparatus according to a fifth embodiment of the present invention when replenishing sheets.

FIG. 11 is a diagram illustrating a state in which a separation cam release mechanism of a sheet feeding device according to a fifth embodiment of the present invention is replenishing sheets.

FIG. 12 is a main cross-sectional view of an example of an image forming apparatus equipped with the sheet feeding device of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Sheet support member 1a Sheet loading surface 2 Slope separation member 2a Separation slope 3 Feed roller 4 Drive shaft 5, 12, 41, 51 Feed roller arm 6, 14, 21, 24, 32, 43, 52 Separation roller 7, 15, 22, 24, 33, 44 Separate roller arm 53 Opening 59 Spring

Claims (14)

[Claims] A sheet support unit configured to stack and support the sheets; a sheet feed roller that feeds the sheet supported by the sheet support unit and feeds the sheet; and a separation unit that separates the sheet sent by the sheet feed roller. A sheet feeding device having a slope, wherein a rotatable separation roller for pressing a sheet upper surface is disposed between the separation slope and the sheet feeding roller, and the separation is performed according to the rigidity of the sheet to be fed. A sheet feeding device provided with roller supporting means for movably supporting the rollers. 2. When the sheet to be separated and fed is a sheet having a low rigidity, the sheet starts from a contact point with the separation roller when the sheet is fed by the sheet feeding roller and fed along the separation slope. In the case of a sheet having a large rigidity, the separation roller is supported by the support means so that the separation roller is pushed up by the sheet and the sheet is bent with the contact point with the paper feed roller as a base point. 2. The sheet feeding device according to claim 1, wherein: 3. The separation roller is arranged at a position shifted from the separation slope in the width direction of the sheet supported by the sheet support means, and a part of the outer circumference of the separation roller is stacked with the sheet from the separation slope. The sheet feeding device according to claim 1, wherein the sheet feeding device is inserted into a side where the sheet is not provided. 4. The paper feed roller is provided on a paper feed roller arm rotatably held by a roller arm shaft, and the support means rotatably supports the separation roller, and is rotatable by a support shaft. The sheet feeding device according to any one of claims 1 to 3, further comprising a roller holder held in the sheet feeding device. 5. The sheet feeding device according to claim 4, wherein a rotation support shaft of the roller holder is the roller arm shaft. 6. The sheet feeding device according to claim 4, wherein a rotation support shaft of the roller holder is provided on the roller arm. 7. The sheet feeding roller is disposed at a position facing the separation slope, and the separation roller is disposed at a position not facing the separation slope on both sides of the separation slope in the sheet width direction. Item 7. The sheet feeding device according to any one of Items 1 to 6. 8. A sheet supporting means for stacking and supporting sheets, a sheet feeding roller for abutting on an upper surface of the sheet supported by the sheet supporting means and sending out the sheet, and a separation for separating the sheet sent out by the sheet feeding roller. A sheet feeding device having a slope, wherein a rotatable separation roller biased toward both the upper surface of the sheet and the separation slope is disposed between the separation slope and the sheet feeding roller, and the feeding is performed. A roller supporting means for movably supporting the separation roller in accordance with the rigidity of the sheet to be fed. 9. When the sheet to be separated and fed is a sheet having a low rigidity, the sheet starts from a contact point with the separation roller when the sheet is fed by the sheet feeding roller and fed along the separation slope. In the case of a sheet having a large rigidity, the separation roller is supported by the roller support means such that the separation roller is pushed up by the sheet and the sheet is bent with a contact point with the paper feed roller as a base point. The sheet feeding device according to claim 8, wherein 10. The separation roller is movably supported on left and right side walls provided in the sheet support means at openings extending along the separation slope, and the separation roller is supported by the separation slope. 10. The sheet feeding device according to claim 8, further comprising a spring for urging both the upper surface of the sheet and the upper surface of the sheet. 11. The apparatus according to claim 1, further comprising a release mechanism for separating said sheet feed roller and said separation roller from a sheet supported by said sheet support means. Sheet feeding device. 12. The apparatus according to claim 11, wherein the release mechanism has a link mechanism that is linked to an operation of an operation unit.
3. The sheet feeding device according to 1. 13. The operating means is a cover which covers a sheet supported by the sheet supporting means and which is openably and closably provided to replenish the sheet to the sheet supporting means, wherein the cover is opened. 13. The sheet feeding device according to claim 12, wherein the sheet feeding roller and the separation roller are separated from a sheet by a sheet. 14. A sheet feeding device according to claim 1, further comprising: an image forming unit that forms an image on a sheet fed by the sheet feeding device. An image forming apparatus comprising: