JP2001199581A - Sheet feeding apparatus and image forming apparatus having the same - Google Patents

Abstract

(57) [Problem] To provide a sheet feeding device capable of preventing generation of noise at the time of sheet separation and an image forming apparatus provided with the same. SOLUTION: While the sheets stacked on the sheet stacking means are separated and fed one by one by a feeding means 60 and a separating means 73, a feeding means passing through a contact portion between the feeding means 60 and the separating means 73. The separating means 73 is rotatably supported at a position near the tangent of the separating means 60, and the separating means 73 is rotated at an angle close to the direction of the force A received by the separating means 73 by the rotation of the feeding means 60.
Is provided so that the separating means 73 does not vibrate even when the separating means 73 has a play.

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 and an image forming apparatus having the same, and more particularly to an apparatus for reducing noise during sheet feeding.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus such as a facsimile, a printer, a copying machine or the like, sheets stacked on a sheet stacking unit are separated one by one by a feeding unit and a separating unit and fed to an image forming unit. There is an apparatus provided with a sheet feeding device as described above.

[0003] By the way, as a separating means of such a conventional sheet feeding apparatus, a claw separation method, a friction piece separation method,
Among them, there is a method using a reverse roller method or the like, and among them, the friction piece separation method is considered to be balanced in terms of cost and performance. However, this method is liable to generate squealing (chattering), and it is necessary to consider the material of the separation pad, which is a friction piece, and the supporting method thereof.

In a conventional sheet feeding apparatus,
For example, as shown in Japanese Patent Publication No. 55-21696, a feed roller is provided as a feeding means, and a shaft support is provided for rotatably supporting the separation pad in a tangential direction at a contact portion of the separation pad as the separation means. In some cases, the separation pad is configured so as not to be bitten or escaped. This is because, if the separation pad becomes self-penetrating or escaping, the pad pressure becomes unstable, and the separation performance tends to be reduced.

[0005]

However, in such a conventional sheet feeding apparatus and an image forming apparatus having the same, the separation pad tends to move in the direction of the force received by the rotation of the feeding roller. When the separation pad has looseness, the separation pressure becomes unstable when the sheet passes through the contact portion between the feeding roller and the separation pad, thereby causing a drawback that noise (chattering) is generated.

The present invention has been made in view of such circumstances, and provides a sheet feeding apparatus capable of preventing generation of noise at the time of sheet separation, and an image forming apparatus having the same. It is intended for.

[0007]

SUMMARY OF THE INVENTION According to the present invention, a sheet stacked on a sheet stacking means is provided so as to be able to approach and separate from the feeding means and the feeding means, and is urged toward the feeding means. In the sheet feeding apparatus configured to separate and feed the sheets one by one by the separated separating means, the separating means is turned to a position near a tangent of the feeding means passing through a contact portion between the feeding means and the separating means. A biasing means for movably supporting and for biasing the separating means at an angle close to the direction of the force applied to the separating means by the rotation of the feeding means is provided.

Further, according to the present invention, the separating means is rotatable with respect to the apparatus main body via a rotating shaft provided near a tangent of the feeding means passing through a contact portion between the feeding means and the separating means. Is held.

Further, according to the present invention, the separating means includes a friction member which comes into contact with the feeding means, and an arm portion which supports the friction member and is rotatably held by the apparatus main body via the rotation shaft. Wherein the urging means urges a fitting portion provided on the arm portion so as to fit with the rotating shaft.

The present invention is characterized in that the biasing means is constituted by a spring member provided on the apparatus main body.

Further, the present invention is characterized in that the relative angle between the direction of the force applied to the separating means by the rotation of the feeding means and the direction in which the urging means urges the separating means is 90 ° or less. It is.

According to the present invention, there is provided an image forming unit, and a sheet feeding device for feeding a sheet to the image forming unit, wherein the sheet feeding device is one of the above. It is assumed that.

Further, as in the present invention, the sheets stacked on the sheet stacking means are separated and fed one by one by the feeding means and the separating means, while the sheets passing through the contact portion between the feeding means and the separating means are fed. By rotatably supporting the separating means at a position near the tangent of the feeding means and providing biasing means for biasing the separating means at an angle close to the direction of the force applied to the separating means by rotation of the feeding means, Even if there is play in the separating means, the separating means is prevented from vibrating.

[0014]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a cross-sectional view illustrating the configuration of a facsimile apparatus which is an example of an image forming apparatus having a sheet feeding apparatus according to an embodiment of the present invention.

In FIG. 1, reference numeral 1 denotes a facsimile apparatus main body (hereinafter, referred to as an apparatus main body), 2 denotes a document table, 3 denotes an image reading section, 4 denotes a recording apparatus, 5 denotes a document transport section, and 11 denotes a multi-tray sheet feeding section. , 13A is a cassette feeding device as a sheet feeding device, 25 is an operation unit, and 26 is a display unit.

Here, the document table 2 is configured to be able to stack a plurality of documents S and to transport the document S so that both sides of the document S stacked on the document table 2 can be aligned. A slider 2a slidable in a direction perpendicular to the direction (the width direction of the document S) is provided. When the document S is a long document, a document tray 2b for preventing the rear end of the document S from protruding from the document table 2 and hanging down is provided so as to be freely drawn.

The image reading section 3 is for reading the image information of the original S. When reading the image information, first, the original S loaded on the original
8 and a separation roller 19 pressed against the friction piece 18.
The sheets S are separated and fed, and then the separated originals S
Is conveyed to the close contact type image sensor 7 by a paper feed roller 21 pressed by a pressing spring 20 and a paper feed roller 22 pressed against the paper feed roller 21.

In the present embodiment, the contact type image sensor 7 irradiates the image information surface of the original S with light from an LED array as a light source, and reflects the reflected light from the image information surface with a self-fox lens. The image information is read by forming an image on the sensor element with (registered trademark).

Next, the original S is pressed against and brought into close contact with the contact image sensor 7 by the original pressing section 6, and the image information of the original S is read by the contact image sensor 7. The paper is discharged onto the document discharge tray 8 by the pressed paper discharge roller 23 and the paper discharge roller 24 pressed against the paper discharge roller 23. During this time, the document S is guided by the upper document guide 16 and the lower document guide 17.

The recording device 4 includes a laser scanner 9 having a laser beam transmitter 9a and a polygon mirror 9b, and an image forming unit 10 having a photosensitive drum 10a. Here, the laser scanner 9 emits a laser beam from a laser beam transmitter 9a based on a document signal output from a CPU 301 shown in FIG. 11, which will be described later, and thereafter this laser beam is transmitted to an image forming unit 10 by a polygon mirror 9b. The photosensitive drum 10a is irradiated with scanning light to form image information on the surface of the photosensitive drum.

On the other hand, the image forming section 10 includes a photosensitive drum 10
a, a primary charger 10b, a developer roller 10c, a cleaning blade 10f, and the like.
0b uniformly charges the surface of the photosensitive drum 10a, and a latent image formed on the charged photosensitive drum surface by the laser scanner 9 is visualized by toner supplied from the developing roller 10c. .

The photosensitive drum 10a, the primary charger 10b, the developer roller 10c, and the cleaning blade 10f are integrally incorporated in a recording cartridge 10e that is detachable from the apparatus main body 1. Further, a transfer charger 10g is arranged around the photosensitive drum 10a. Further, a thermal fixing device 10h, a pair of paper discharge rollers 10j, and a pair of face-down paper discharge rollers 10k are arranged in the recording paper conveyance path downstream of the photosensitive drum 10a.

The multi-tray paper feed unit 11 is provided above the rear cover 28. The recording paper inserted from the multi-tray paper feed unit 11 is separated and conveyed one by one. To be sent to

On the other hand, the cassette feeding device 13A is disposed at the bottom of the apparatus main body 1, and is a cassette 13 serving as sheet stacking means for stacking a plurality of recording materials (sheets) P.
A separating roller 60 as a feeding unit for feeding the recording material P stored in the cassette 13;
A separation pad 73 is provided as separation means for separating the recording material P one by one by pressing the recording material P one by one.

Here, in this cassette, as shown in FIG. 2, width regulating plates 32, 3 for regulating the position in the width direction of the recording material.
3 are arranged, and a side pressure spring (not shown) for urging the recording material toward the other width regulating plate 32 is attached to one width regulating plate 33. In addition, these width regulating plates 3
Claws 35 for suppressing curling of the recording material
35 are formed respectively. Further, a rear end regulating plate 34 for regulating the position of the rear end of the recording material is provided in the cassette.
(See FIG. 1).

Further, an intermediate plate 36 for stacking and supporting the recording material is disposed at the bottom of the cassette 13. The intermediate plate 36 is urged by the lifter arm 38 toward the separation roller to rotate. It has become.

Here, as shown in FIGS. 3 and 4, the lifter arm 38 is attached to a lifter shaft (support shaft) 37 rotatably supported by a bearing 69 fixed to the apparatus main body 1. . A lifter lever 39 is attached to one end of the lifter shaft 37. The lifter lever 39 is always urged by a lifter spring 40 attached to a hook portion 39a of the lifter lever 39 in a direction in which the lifter arm 38 lifts the middle plate 36. Have been.

By rotating the middle plate 36 upward by the lifter arm 38, the recording material P stacked on the middle plate 36 is pressed against the separation roller 60.

On the other hand, the separation roller 60 is attached to the separation roller shaft 62 via the one-way clutch 50 as shown in FIG.
Is connected to a power source (not shown) via an input clutch 61 attached to one end of the motor. The separation roller shaft 62 is rotatably supported by a bearing 63 provided on the apparatus main body 1, and is mounted on the separation roller 60 and the intermediate plate 36 at one end side to which the input clutch 61 is attached. A separation cam 64 for selectively separating the recording material P from the recording material P is provided.

By the way, at the tip of the cassette 13, FIG.
As shown in FIG. 7, a tip projection 70 is integrally formed, and when the cassette 13 is mounted in the apparatus main body 1, the separation lever 71 is rotated by the tip projection 70.

The separation lever 71 is rotatably supported by the lifter shaft 37, and is rotatable with respect to the apparatus main body 1 via a rotation shaft 74 provided on a fulcrum member 74A on the upper surface. A separation spring (compression coil spring) 72 is attached as urging means for urging the separation pad 73 freely attached to the separation roller 60 side.
The separation pad 73 includes a friction member 73a that comes into contact with the separation roller 60, and a fitting portion 73b that supports the friction member 73a and fits with the rotation shaft 74.
Arm 7 rotatably held by the apparatus main body 1 through the
3c.

Therefore, when the cassette 13 is mounted in the apparatus main body 1, the friction member 73a of the separation pad 73 can be urged toward the separation roller 60 by rotating the separation lever 71. Accordingly, the recording material P can be separated and fed one by one by the separation roller 60 and the separation pad 73.

The recording material P separated and fed in this manner is
Is then conveyed along a guide 75 and further inverted by conveying rollers 29 and 30, a cover-side U-turn guide 28a disposed on the rear cover 28 and a main-unit U-turn guide 28b disposed on the apparatus main body 1 side. Then, the sheet is conveyed to the image forming unit 10.

In the figure, reference numeral 77 denotes a convex portion formed on the apparatus main body 1. When the cassette 13 is detached from the apparatus main body 1, the convex portion 77 is provided with a separation spring 72 as shown in FIG. It comes into contact with the separation lever 71 that is pressed.

Next, the feeding operation of the cassette feeding device 13A having such a configuration will be described.

When the cassette 13 is mounted on the apparatus main body 1, the projecting end 70 of the cassette 13 pushes up the separation lever 71 as shown in FIG. As a result, the friction member 73a of the separation pad 73 is urged against the separation roller 60 at a predetermined separation pressure G (2N in the present embodiment) by the repulsive force (spring force) of the separation spring 72.

The cassette 1 is located at the bottom of the apparatus body 1.
3 when the tip projection 70 is inserted to a predetermined position,
The bottom plate 1a is formed in such a size and shape as to enter under the tip projection 70. A leg 112 is provided at a position corresponding to the tip of the tip projection 70 of the bottom plate 1a.

By providing such a leg portion 112, the tip end protruding portion 70 of the cassette 13 which has received the reaction force of the separation spring 72 is moved by the leg portion 112 to a main body installation surface (usually a desk on which the apparatus is placed). , Etc.), and as a result, a desired separation pressure can be generated between the separation roller 60 and the separation pad 73.

As a result, the value of the separation pressure G between the separation roller 60 and the separation pad 73 by the separation spring 72 is stabilized, and the performance of separating the recording material by the separation roller 60 and the separation pad 73 is stabilized. Further, the reaction force received by the distal end projection 70 of the cassette 13 is in the normal direction to the mounting direction of the cassette 13, so that the reaction force is not received in the mounting direction of the cassette 13, and The mounting position with respect to is stabilized.

By the way, in the paper feed standby state immediately after the cassette 13 is mounted on the apparatus main body 1, the lifter lever 39 biased by the lifter spring 40 is connected to the separation roller 60 as shown in FIG. Rotation is restricted by contacting the separation cam 64 disposed coaxially.

After that, when the pickup solenoid (not shown) is activated, the input clutch 61 enters the drive transmission state, and when the separation roller shaft 62 starts to rotate, the separation cam 64 starts to rotate. When the separation roller shaft 62 rotates, the rotation of the separation roller shaft 62 is transmitted to the separation roller 60 by the one-way clutch 50, and the separation roller 60 starts rotating in the direction of arrow J in FIG.

Next, as the separation cam 64 rotates, the spring force of the lifter spring 40 causes the lifter lever 39 to move along the outer peripheral shape of the separation cam 64 as shown in FIGS.
When is rotated, the lifter arm 38 pushes up the middle plate 36 to the separation roller 60 side.

When the lifter arm 38 pushes up the middle plate 36 (the weight of the middle plate 36 and the weight of the recording sheet P) on which a plurality of sheets are stacked, the lifter shaft 37 acts downward in the drawing. Receive force H. However, immediately below the bearing 69 that rotatably supports the lifter shaft 37, FIG.
As shown in FIG. 7, a leg portion 111 is formed. By supporting the lifter shaft 39 with the leg portion 111, the position of the lifter shaft 39 does not change.

Therefore, the middle plate 36 of the lifter arm 38
Loss of the force for pushing up the intermediate plate 36 by the lifter arm 38 is stabilized, and the separation roller 60
The separation performance (paper feed performance) is also stabilized.

Next, when the separation cam 64 further rotates,
The recording material P on the middle plate front end 67 contacts the separation roller 60, and the separation cam 64 and the lifter lever 3 as shown in FIG.
When a space 65 is generated between the recording material P and the recording material P, the recording material P stacked on the intermediate plate 36 is pressed against the separation roller 60 by the urging force of the lifter spring 40, and the recording material P is pressed by the separation roller 60 in FIG. Only one sheet is pulled out (fed) as shown in FIG. At this time, the recording paper P has its side and rear end surfaces regulated by width regulating plates 32 and 33 (see FIG. 2) and rear end regulating plate 34 (see FIG. 1) provided in the cassette.
Skew and non-feeding do not occur.

Next, when the separation cam 64 is further rotated, and the lifter lever 39 is pushed down by the separation cam 64, the lifter arm 38 is rotated in a direction away from the separation roller 60, whereby the middle plate 36 is moved to the position shown in FIG. As shown in (2), it rotates so as to descend by its own weight, and after the state of (c), the intermediate plate 36 returns to the initial position as shown in (d).

During the period from (b) to (d), no pressing force is applied to the recording material P by the middle plate 36. In this state, the recording material P is separated from the separation roller 60 as shown in FIG. And the separation pad 73, the sheets are separated one by one by the separation roller 60 and the separation pad 73, and are conveyed along the separation guide 75.

Further, after the rotation of the separation roller shaft 62 and the separation cam 64 is completed, the recording material P
The recording material P is conveyed by the rotations of the recording rollers 9 and 30, whereby the slack of the recording material P is removed between the recording material P and the separation roller 60. At this time, the lock state of the separation roller 60 with the separation roller shaft 62 is released by the one-way clutch 50, and the separation roller 60 follows the movement of the recording material P.

Thereafter, when the rear end of the recording material P passes through the nip between the separation roller 60 and the separation pad 73, the rotation of the separation roller 60 and the one-way clutch 50 is stopped. When the conveyance of the recording material P is completed, the middle plate 3
6 and the like return to the original standby state.

By the way, as described above, the cassette feeding device 1
The leading end position of the recording paper P fed from 3A (or the multi-tray paper feed unit) is detected by the registration sensor 28c shown in FIG. 1, and thereafter, the leading end of the toner image formed on the photosensitive drum 10a is detected. After the timing of paper feeding and image output is adjusted so that the leading ends of the recording materials P coincide, the transfer charger 1
0g and the photosensitive drum 10a.

FIG. 10 is a diagram showing an image recording operation of the recording apparatus 4. The laser light emitted from the laser beam transmitter 9a is deflected by being reflected by the polygon mirror 9b, and is deflected by the optical system 9d. Then, the light is irradiated onto the photosensitive drum 10a via the return mirror 9c (main scanning). At this time, the head is caught by the photodetector 9e, and the irradiation position is determined. While the main scanning is completed for one line, the photosensitive drum 10a rotates one line (sub-scanning).

The image formed on the photosensitive drum 10a as described above is developed by the developer roller 10c, and thereafter, is transferred to the lower surface of the recording material P by the transfer charger 10g. Thereafter, the recording material P on which the image has been transferred is conveyed along the conveyance guide 27, and thereafter, the toner image is fixed by the heat fixing device 10h, and then conveyed to the discharge roller pair 10j. I have.

When discharging the recording material P by the discharge roller pair 10j, the user can select one of two output modes (so-called face-down discharge and face-up discharge). it can. Here, face-down discharge means a mode in which the recording material P is discharged so that the output page is aligned with the print surface facing down, and face-up discharge means the recording material with the print surface facing upward. This is a format in which P is discharged and the output contents can be checked even during the discharge.

The two types of switching are performed by switching the recording paper transport path switching flapper 14 shown in FIG. 1 to switch the transport path. FIG. 3 shows a face-down sheet discharge state. That is, when performing face-down discharge, the direction of the recording material P is changed upward by the recording paper conveyance path switching flapper 14, and then the recording material P is changed.
Is guided along the face-down guide 15 and is discharged to the face-down recording paper discharge tray 12 by the face-down discharge roller pair 10k.

On the other hand, when performing face-up discharge, the direction of the recording paper transport path switching flapper 14 is changed by a switching lever (not shown), and the original is discharged to the original discharge tray 8 side.

In the present embodiment, the number of recording materials that can be loaded on the cassette 13 is about 250, and the cassette 13 is configured to be pulled out toward the mounting body 1 in the front direction (front loading). method). Further, the stackable recording paper sizes are A4, letter, and two types, and FIG. 1 shows a state in which the rear end regulating plate 34 is set at the position of the letter size.

When the cassette 13 is removed from the apparatus main body 1 to replenish the recording material P, for example, the leading end 70 of the cassette 13 is separated from the separation lever 71, so that the separation pad 73 is deflected by its own weight. It rotates clockwise, and further rotates in the clockwise direction until the separation lever 71 comes into contact with the projection 77 as shown in FIG. At this time, as described later, the leaf spring 81 presses the outer periphery of the fitting portion 73b of the separation pad 73, but the outer periphery is a smooth cylinder and does not hinder the rotation of the separation pad 73.

Here, when the separation pad 73 separates from the separation roller 60, the separation pressure between the separation pad 73 and the separation roller 60 is released.
The recording material P sandwiched between the sheet and the separation roller 60 becomes free. As a result, when the cassette 13 is pulled out of the apparatus main body 1, the recording material P is drawn out together with the cassette 13, and does not remain between the separation pad 73 and the separation roller 60. Accordingly, it is possible to prevent a problem that the recording material P remains on the separation roller 60 side when the cassette 13 is pulled out from the apparatus main body 1.

Further, the apparatus main body 1 is configured such that the document placing table 2, the face-down paper discharge tray 12 and the like can be opened and closed as a unit (unit), and by opening the unit, the recording cartridge 10e is pulled out and replaced. I can do it. Further, the unit is provided with an interlock mechanism (not shown), and the recording device 4 does not operate when the unit is open or the recording cartridge 10e is not set in the apparatus main body 1.

The recording cartridge 10e is provided with a drum exposure prevention shutter (not shown) that is interlocked with the setting of the recording cartridge 10e in the apparatus main body 1.
The drum shutter is opened when the unit is opened and the recording cartridge 10e is set in the apparatus main body 1, while the recording cartridge 10e is opened in the apparatus main body 1
By closing when taken out from the photosensitive drum 1
0a is prevented.

If a jam occurs during recording, the unit, the rear cover 28, the face-down guide 15, or the cassette 13 is opened, so that the recording staying in the apparatus main body 1 is opened. The material P can be taken out.

FIG. 11 is a block diagram of a control system 300 of the facsimile machine.

In the figure, reference numeral 301 denotes a CPU for controlling the entire facsimile apparatus.
It is composed of a ROM for storing a control program of the PU and the MPU, a RAM used as a work area for various data processing and a temporary recording section for image information, an image processing section for performing image scaling, resolution conversion, and the like. I have.

The CPU 301 is provided with a calendar and a clock function having a well-known configuration, and an area for storing important system setting information such as one-touch key destination information and software switch information in the RAM is provided with a power failure due to a battery backup. Is protected from accidental obstacles.

The control system of this facsimile machine is as follows:
The CPU 301 described above and the following elements 302 to 310 are
It is configured to be connected through an interface.

The operation unit 25 includes various key switches such as a numeric keypad, a function key, a one-touch key, a start key, and a stop key. The display unit 303 includes an LCD for displaying various messages, It is composed of various LEDs for displaying the mode and the like.

The image reading unit 3 includes, in addition to the contact image sensor 7 for reading an image described above, a driving unit such as a reading motor, an image processing unit for shading and binarizing the read image, The recording device 4 includes various sensors for performing document detection and the like. The recording device 4 includes, in addition to the laser scanner 9 described above, a recording unit that controls an electrophotographic process, a driving unit such as a recording motor, It comprises an image processing unit for performing smoothing and the like, and various sensors for detecting recording paper and the like.

In the figure, reference numeral 306 denotes an outgoing / incoming call,
The communication control unit 306 performs encoding of image data and the like. The communication control unit 306 has a connection unit including a MODEM, an NCU, and the like, and a communication network 307 is connected to the connection unit. Reference numeral 309 denotes a CPU external interface for directly transmitting and receiving data from the CPU 301. The CPU external interface 309 includes, for example, RS232C, SCS
The apparatus is used as a scanner printer of the external computer by connecting to a computer external to the apparatus through a line such as I or LAN. An HDD 310 is used as a large-capacity nonvolatile memory for storing image information and the like.

The pivot 74 of the separation pad 73
As shown in FIG. 12, the center is located near the tangent of the separation roller 60 passing through the contact portion between the separation roller 60 and the separation pad 73, so that the force applied to the separation pad 73 by the rotation of the separation roller 60 is reduced. , So as not to affect the pressing force of the separation spring 72. The fulcrum member 74A provided with the rotating shaft 74 is attached to the apparatus main body 1 with screws, so that the assembling property is good and the parts cost is low.

On the other hand, as shown in FIG. 1, a power supply unit 79 serving as a power supply unit is provided at the rear of the apparatus main body 1.
Further, a power supply frame metal plate 78 is provided below the power supply unit 79 for grounding earth and preventing electromagnetic wave noise, and a power supply cover 80 is provided on an upper portion as an exterior.

Here, the power supply frame sheet metal 78 is bent into an L-shape on the cassette feeder side so as to cut off the cassette feeder 13A and the power supply unit 79, and thus is shielded by the power supply frame sheet metal 78. By doing so, even if the power supply unit 79 ignites, the cassette feeding device 1
3A can be prevented from being affected.

Further, by arranging the power supply unit 79 alone outside the main body of the apparatus instead of inside, if it becomes necessary to replace the power supply unit 79 due to a failure or the like, it is only necessary to remove the power supply cover 80. Since the power supply unit 79 can be accessed, there is an effect that the work is easy.

Further, a bottom plate reinforcing sheet metal 76 as a support is provided on the upper portion of the bottom plate 1a of the apparatus main body 1, for example, as shown in FIG. And this bottom plate reinforcing sheet metal 7
6, the rigidity of each part is improved to prevent squealing (chattering) of the separation pad 73, etc., and the shape and dimensions are corrected, the grounding ground is strengthened, and the like. In addition, this bottom plate reinforcing sheet metal 7
12 has an L-shape at the upper end as shown in FIG. 12, and has an opening 76a at the center of the upper end as shown in FIG. 13 so as not to hinder the rotation of the separation pad 73. In addition, as shown in FIG.
The bent end of 8 is fastened with a screw 82 so as to overlap the bottom plate reinforcing sheet metal 76.

When the separation roller 60 is rotated in the J direction to feed the recording material P as shown in FIG. 12, the rotation causes the separation pad 73 to receive a tangential force A. Due to the intermittent change in the frictional force between the recording material P and the separation pad 73, the force A received by the separation pad 73 varies. When the force A received by the separation pad 73 fluctuates in this manner, the separation pad 73 is
Attempts to vibrate in the backlash fitting with b, and this vibration generates noise (pad noise).

Therefore, in the present embodiment, a leaf spring 81 is provided as urging means for urging the fitting portion 73b of the separation pad 73 toward the separation roller 60 (upward of the apparatus). Here, this leaf spring 81 is fastened to the power supply frame metal plate 78 with screws 82 and, as shown in FIG. It has two arms 81b for pressing with (for example, 2N).

Then, by providing such a leaf spring 81 and pressing the separation pad 73 upward by the spring force B of the leaf spring 81, the separation pad 73 is fitted to the rotating shaft 74 and the fitting portion 73b. Vibration in the play can be suppressed, and occurrence of pad squeal can be prevented.

In this case, the leaf spring 81 presses the fitting portion 73b of the separation pad 73.
Therefore, the pressing force G of the separation pad 73 by the separation spring 72 is hardly affected. That is, the separation performance does not decrease.

In order to suppress the vibration of the separation pad 73, the direction (angle) of the force A applied to the separation pad 73 and the force (angle) of the spring force B of the leaf spring 81 is more effective.
Therefore, the relative angle between these two forces A and B is 90 °.
It is desirable to set the mounting position and the like of the leaf spring 81 so as to be (１ ／ π rad) or less.

In the above description, a case in which a laser scanner is provided as the recording device 4 has been described as an example.
Other electrophotographic systems, thermal transfer systems and ink jet systems may be used. Further, the number of cassettes 13, the type of recording material to be used, and the number of stacked sheets are not particularly limited as long as they do not deviate from the configuration of the present invention.

Further, the sheet feeding apparatus according to the present invention is not limited to the above-described feeding of the recording material, but also the original feeding for feeding the original sheet to an optical system as an image reading means or a contact type image sensor. The apparatus can be applied to an image forming apparatus such as an electrophotographic copying machine.

In the above description, the case where the separation pad 73 is pivotally supported on the rotation shaft 74 provided on the fulcrum member 74A has been described. The driving shaft may be supported by the fulcrum member 74A. Further, the rotating shaft may be supported by the bottom plate 1a, the bottom plate reinforcing sheet metal 76, or the like.

[0083]

As described above, according to the present invention, the separating means is rotatably supported at a position near the tangent of the feeding means passing through the contact portion between the feeding means and the separating means, and the separating means is provided. Is biased by the biasing means at an angle close to the direction of the force received by the separating means due to the rotation of the feeding means, so that even if the separating means has backlash, the separating means can be prevented from vibrating. It is possible to prevent generation of noise at the time of sheet separation.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a schematic configuration of a facsimile apparatus as an example of an image forming apparatus including a sheet feeding apparatus according to an embodiment of the present invention.

FIG. 2 is a plan view of the sheet feeding device with a part of a cassette cut away.

FIG. 3 is a plan view of FIG. 2 with a part cut away;

FIG. 4 is a front view in which a part of the cassette is cut away.

FIG. 5 is a diagram illustrating a configuration of a separation roller of the sheet feeding device.

FIG. 6 is an enlarged sectional view of a main part of the facsimile apparatus.

FIG. 7 is a diagram showing a state when a cassette is taken out from the sheet feeding device.

FIG. 8 is a diagram illustrating a part of the sheet feeding operation of the sheet feeding apparatus.

FIG. 9 is a view for explaining another part of the feeding operation of the sheet feeding apparatus.

FIG. 10 is a conceptual diagram illustrating the operation of the recording device of the facsimile machine.

FIG. 11 is a control block diagram of the facsimile apparatus.

FIG. 12 is an enlarged view of a main part of the sheet feeding device.

FIG. 13 is a rear view of a main part of the sheet feeding device.

DESCRIPTION OF SYMBOLS 1 Facsimile machine main body 10 Image forming unit 13A Sheet feeding device 13 Cassette 60 Separation roller 72 Separation spring 73 Separation pad 73a Friction member 73b Fitting unit 73c Arm unit 74 Rotating shaft 81 Leaf spring

Claims (6)

[Claims] 1. A sheet loaded on a sheet loading means,
In a sheet feeding apparatus which is provided so as to be able to approach / separate from the feeding means and the feeding means and is separated and fed one by one by a separating means urged toward the feeding means, The separating means is rotatably supported at a position near a tangent to the feeding means passing through a contact portion between the feeding means and the separating means, and in a direction of a force applied to the separating means by rotation of the feeding means. A sheet feeding device, further comprising an urging means for urging the separating means at a close angle. 2. The apparatus according to claim 1, wherein said separating means is rotatably held on a main body of the apparatus via a rotating shaft provided near a tangent of said feeding means passing through a contact portion between said feeding means and said separating means. The sheet feeding device according to claim 1, wherein: 3. The separating unit has a friction member that contacts the feeding unit, and an arm that supports the friction member and is rotatably held by the apparatus main body via the rotation shaft. ,
The sheet feeding device according to claim 1, wherein the urging unit urges a fitting portion provided on the arm portion so as to fit with the rotation shaft. 4. The sheet feeding apparatus according to claim 1, wherein said urging means is constituted by a spring member provided on said apparatus main body. 5. The apparatus according to claim 1, wherein the relative angle between the direction of the force applied to the separating unit by the rotation of the feeding unit and the direction in which the urging unit urges the separating unit is 90 ° or less. Sheet feeding device. 6. An image forming unit, comprising: a sheet feeding device that feeds a sheet to the image forming unit; wherein the sheet feeding device is the one according to claim 1; An image forming apparatus comprising: