JPH11100134A - Sheet feeding device and image processing device - Google Patents

Abstract

(57) [Problem] To provide a sheet feeding apparatus in which a sensor flag operates reliably even when the apparatus is downsized, and an image processing apparatus using the same. SOLUTION: In a sheet feeding apparatus for separating and feeding a set sheet, a sheet stacking member which can be opened and closed with respect to the apparatus main body and on which a sheet can be stacked, and a sheet stacked on the sheet stacking member are provided. A sheet flag that rotates, a holding member that rotatably holds the sheet flag, a link member that connects the holding member and the sheet stacking member, and a feeding rotator that applies a feeding force to the sheet. Wherein the holding member is configured to rotate in conjunction with the opening / closing operation of the sheet stacking member.

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 for separating and feeding sheets and an image processing apparatus using the same.

[0002]

2. Description of the Related Art In a conventional image forming apparatus such as a laser printer or an image processing apparatus such as a document reading apparatus, a plurality of sheets are set on a tray or the like and separated and fed one by one. The transmission device is generally configured as shown in FIG.

When the sheet S is set on the stacking member 50 and the roller shaft 51 is driven, the pickup roller 52 and the cam 53 on the same axis as the feeding rotating body start rotating in the direction of arrow m.
The middle plate 54 is constantly urged in a direction indicated by an arrow n by a feed spring (compression spring) 55, and the protrusion 54 a of the middle plate 54 is in contact with the cam 53. The middle plate 54 is rotatable about a shaft 54b, and when the pickup roller 52 rotates in the direction of arrow m,
Since the projection 54a of the middle plate 54 comes off the cam 53, the middle plate 54 is pushed up by the compression spring 55 in the direction of arrow n. As a result, the top sheet of the sheet bundle is
Is fed in the direction of arrow p.

When the sheets S are double-fed when being picked up, they are separated by a separation pad 56. The separation pad 56 is constantly urged in the direction of arrow q by a separation spring (compression spring) 57 and is constantly in pressure contact with the pickup roller 52 at a constant pressure. Thereafter, the sheet S is transferred to the image processing unit via the guide path 59 by the conveying roller pair 58.
The sheet is conveyed to 60 and predetermined image processing is performed.

FIGS. 10 and 10 show a configuration for detecting whether or not a sheet is set on the stacking member 50 in the image processing apparatus.
It is configured as shown in FIG. That is, the sheet S is stacked on the stacking member 50 by opening the front cover 61, and the sheet is set on the sheet stacking member 50 and the middle plate 54 by adjusting the position of the sheet by the side regulating member 62. At this time, a rotation center 63a defined on the upstream side of the pickup roller 52
The sheet flag 63 that rotates around the center is rotated by the leading edge of the sheet, and the light interrupt of the photo interrupter 64 is released to recognize the presence of the sheet. Conversely, when the sheet S does not exist, the sheet flag 63 shields the photo interrupter 64 from light, as shown by the broken line in FIG. Thus, the presence or absence of a sheet is detected.

[0006] Further, as shown in FIG.
A stacking control label 65 is attached to the inner side surface of the sheet 62 so as to control the sheet stacking height on the sheet stacking member 50.

[0007]

However, in the above-described conventional sheet feeding apparatus, as shown in FIG. 10, the center of rotation 54b of the intermediate plate 54 is
From the center of rotation 54
b is a factor that determines the size of the apparatus, and when the front cover 61 is closed, the distance from the front surface of the main body to the pickup roller 52 becomes longer, and as a result, the entire apparatus becomes larger.

In order to reduce the size of the apparatus, a configuration is conceivable in which the depth of the middle plate is reduced, the middle plate is moved up and down in parallel, and the rotation fulcrum of the sensor flag is movable. However, in this case, it is necessary to ensure that the sensor flag falls by its own weight when the sheet stacking member is opened. Further, it is necessary to increase the strength of the sensor flag so that the sensor flag does not break when rotated.

In addition, the conventional loading control label 65 is not visible from the outside of the side control member 62, and further requires an additional assembly process for attaching another member to the control member 62. Requires a step of removing it.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a sheet feeding apparatus in which a sensor flag operates reliably even when the apparatus is downsized, and an image processing apparatus using the same. To provide.

Another object of the present invention is to provide a sheet feeding apparatus capable of easily confirming a sheet stacking regulation sign on a sheet stacking member and increasing the number of assembling and disposal steps for the stacking regulation sign, and an image using the same. A forming apparatus is provided.

[0012]

A typical configuration according to the present invention for achieving the above object is a sheet feeding apparatus for separating and feeding set sheets, which can be opened and closed with respect to the apparatus main body. A sheet stacking member capable of stacking sheets, a sheet flag rotated by a sheet stacked on the sheet stacking member, a holding member rotatably holding the sheet flag, the holding member and the sheet stacking A link member connecting the members, and a feeding rotating body for applying a feeding force to the sheet, wherein the holding member is configured to rotate in conjunction with the opening / closing operation of the sheet stacking member. I do.

In the above configuration, since the holding member for holding the sensor flag rotates in conjunction with the opening and closing of the sheet stacking member, the sensor flag is reliably set to the home position when the sheet stacking member is opened. In addition, even when the user attempts to lift the sensor flag, the sheet stacking member is simultaneously lifted, and a force that deforms the sensor flag is prevented from being applied.

A stopper is provided at one end of the link member to be inserted and locked in a groove formed in the sheet stacking member, and a first taper portion serving as a guide when the stopper is pressed into the groove. And the provision of the second tapered portion, which serves as a guide when the stopper portion is pulled out from the groove portion, facilitates press-fitting and pulling-out of the link member, and facilitates assembly and disassembly of the device. .

Further, the sheet stacking member is provided with a slidable side guide member for aligning a side end of the placed sheet, and a through hole is provided in a sheet contact surface of the side guide member, or the sheet contact member is provided with a through hole. By configuring the surface with a transparent or translucent material, the sheet stacking restricted position can be easily confirmed.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of a sheet feeding apparatus according to the present invention and an image processing apparatus using the same will be described.
This will be described with reference to the drawings.

[First Embodiment] A sheet feeding apparatus according to a first embodiment and an image processing apparatus using the same will be described with reference to FIGS. 1 is an explanatory perspective view showing a main part of the sheet feeding unit, FIG. 2 shows a state when the sheet stacking member is opened and closed, (a) is a state where the sheet stacking member is opened, and (b) Is an explanatory view showing a state in which the sheet stacking member is closed, FIG. 3 is an overall schematic explanatory view of an image forming apparatus using the sheet feeding apparatus, FIG. 4 is a sectional explanatory view showing a separation feeding configuration, and FIG. FIG. 6 is a perspective explanatory view showing a configuration in which a sheet is pressed against and separated from a pickup roller, FIG. 6 is an explanatory view of a configuration of a link member, and FIG. 7 is an explanatory view of a sheet stacking restriction sign of a side guide member.

Here, the overall configuration of the image forming apparatus using the sheet feeding device will be described first, and then the configuration of the sheet feeding device will be described.

{Image Forming Apparatus} FIG. 3 shows a laser beam printer A using an electrophotographic image forming means as an image processing means, in which a loading tray 1 which is a sheet loading member also serving as a front cover is opened. Thereby, the sheets S can be stacked. When a plurality of sheets S are set on the stacking tray 1 and the start key is pressed, only one of the uppermost layers is separated and fed by a sheet feeding device B to be described later, and the sheet is fed to the conveying roller pair 2 and the guide path. By 3, it is conveyed to an image forming means 4 as an image processing means.

The image forming means 4 is provided with a charging means, a developing means and a cleaning means (not shown) around the photosensitive drum 5, and after the charging means uniformly charges the surface of the photosensitive drum 5, a laser A latent image is formed by selective exposure by the scanner 6, and the latent image is developed into a visible image by developing with toner. Then, a transfer bias voltage is applied to the transfer roller 7 to transfer the toner image onto the sheet S to form an image, and the toner remaining on the photosensitive drum 5 after the transfer is removed by a cleaning unit.

On the other hand, when the sheet S to which the toner image has been transferred passes through the fixing roller pair 8 serving as fixing means, heat and pressure are applied to fix the toner image, and the discharge roller pair 9, 10
And the discharge section in the face-down state by the guide path 11
It is discharged to 12.

{Sheet Feeding Apparatus} Next, the structure of a sheet feeding apparatus B for separating and feeding sheet bundles set on the stacking tray 1 one by one will be described.

(Sheet Separation Feeding Configuration) The stacking tray 1 is rotatable about a shaft 1a, and can be opened and closed with respect to the apparatus main body by rotating this. As shown in FIG. 3, when the stacking tray 1 is opened and a sheet bundle is set, a sheet feeding plate 13 is provided at a position where the leading edge of the sheet rides. A pickup roller 14, which is a rotating body, is provided. Further, a separation pad 15 as a pressing member is pressed against the pickup roller 14 by a separation spring 16,
The sheet S is prevented from being double fed.

FIG. 5 shows the feed plate 13 and the pickup roller.
14 is shown. The feeding plate 13 has a loading surface 13a and a tube portion 13b,
It has a stopper 13c and a separation sheet material 13d for preventing double feeding of the lowermost sheet. Reference numeral 13e is a through hole of the tube portion 13b. The loading surface 13a is located below the pickup roller 14, and the width in the depth direction is
It is configured to be narrower than that. A support shaft 17 fixed to the main body of the image forming apparatus is inserted into a hole 13e of the feed plate 13, and is guided by the shaft 17 when the feed plate 13 performs a vertical piston motion during image formation. It has become. A feeding spring 18 formed of a compression spring is attached to the outer periphery of the tube portion 13b.

A pressing force changing means for changing the pressing force of the separation pad 15 on the pickup roller 14 is provided. As shown in FIG. 5, a cam 20 is attached to the end of the roller shaft 19 of the pickup roller 14, and when the pickup roller 14 rotates in the direction of arrow a in FIG. One end of a lever 22 rotatable around a rotation shaft 21 attached to the forming apparatus main body is pushed down by the cam 20, and the other end is pushed up. The end of the lever 22 is provided with a hole 22a of a size through which the tube portion 13b of the feed plate 13 can freely pass but the feed spring 18 cannot pass. The separation spring 16 does not pass through the same end as the side where the hole 22a is drilled.
A groove 22b is provided in the shaft portion 23 for supporting the shaft. The shaft 23 is fixed to the main body of the image forming apparatus.
Thereby, the separation spring 16 and the groove 22b are guided.

In the sheet feeding apparatus having the above-described structure, the feeding spring 18 is provided between the end of the lever 22 and the loading surface 13a of the feeding plate 13, and the end of the lever 22 is A separation spring 16 exists between the separation pad 15 and the separation pad 15. Because of this, the lever
When the end of 22 pushes up the feeding spring 18 and the separation spring 16 directly, the upper end of the feeding spring 18 pushes up the stacking surface 13a and the tip of the sheet S, and the upper end of the separation spring 16 picks up the separation pad 15 14 is pressed with a stronger force to prevent double feeding. Then, when the uppermost sheet of the sheet bundle strikes the surface of the pickup roller 14, the feeding spring 18 starts to be compressed. Thus, the uppermost layer of the sheet S receives a conveying force by the pickup roller 14 rotating in the direction of arrow a.

When the sheets S are double-fed when being picked up, they are separated by the separation pad 15.
After one sheet is picked up, the cam 20 shown in FIG. 5 lowers the stacking surface 13a of the feeding plate 13 to release the nip between the stacked sheet bundle and the pickup roller 14, and the pressure of the separation spring 16 is reduced. It is going to decrease.

As described above, the sheet can be separated and fed by the pickup roller 14 by moving the narrow feeding plate 13 up and down, and the apparatus can be downsized compared to the conventional feeding apparatus. be able to.

(Link Configuration of Sensor Flag) Next, a configuration for detecting the presence / absence of sheets loaded on the loading tray 1 will be described. In FIG. 1, 24 is the loading tray 1
Is a sensor flag that is rotated by the end of the sheet placed on the sheet, and a flag section 24a that shields the photo interrupter 25.
And a probe portion 24b for detecting the sheet S when the sheet S is stacked on the stacking tray 1, and a rod portion 24c existing on the X axis.

FIG. 1 shows a state where sheets S are not stacked. In this state, the flag unit 24a is a photo interrupter.
Since the block 25 is shielded, the apparatus determines that there is no sheet. The sensor flag 24 is held on a flag cover 26 which is a holding member so as to be rotatable about the X axis. The flag cover 26 is rotatably attached to the feed shaft 19. One end of a link member 27 is attached to the flag cover 26 so as to be rotatable around the Y axis.
As shown in FIG. 1, the other end of the link member 27 is engaged with the loading tray 1 by a long groove 1b formed in the tray 1, and is prevented from falling out of the long groove 1b.
A stopper 27a is provided at the tip of 27.

FIG. 2 shows the operation of the sensor flag 24 when the loading tray 1 is opened and closed. FIG. 2A shows a state in which a sheet bundle is set. At this time, the probe portion 24b of the sensor is pushed up by the leading end of the sheet S, and the apparatus receives the signal of the photo interrupter 25 and detects the presence of the sheet. FIG. 2B shows a state in which the stacking tray 1 is closed. At this time, the flag cover 26 and the sensor flag 24 held thereon rotate with the rotation of the stacking tray 1 via the link member 27, It is stored inside the device. As described above, the feeding plate 13 is narrow, and the rotation fulcrum of the loading tray 1 is moved to the feeding plate 13 in order to rotate the sensor flag 24 and the flag cover 26 in conjunction with the loading tray 1. Can be located in the vicinity of. Therefore, FIG.
As is clear from FIG. 2B, the distance between the pickup roller 14 and the closed stacking tray 1 can be reduced. For this reason, the entire device is downsized.

When the loading tray 1 is opened, the link member is opened.
The flag cover 26 and the sensor flag 24 are reliably rotated to a predetermined position via 27, and the sheet can be detected.
In this state, the user sets the flag cover 26
2A is lifted in the direction of the arrow in FIG. 2A, the flag cover 26 is linked to the stacking tray 1 by the link member 27, so that the stacking tray 1 is lifted up, and excessive force is applied to the flag cover 26 and the sensor flag 24. Is not added, and the member is not broken.

(Assembly and disassembly of the link member) Next, the assembly and disassembly of the link member 27 will be described. As shown in FIG. 1, the link member 27 supports the shaft portion 27b on the flag cover 26, and inserts and stops the stopper portion 27a in the long groove portion 1b of the loading tray 1, and attaches the stopper portion 27a. 6A, a first tapered portion 27a1 and a second tapered portion 27a2 are provided as shown in FIG.
The first taper portion 27a1 is connected to the stopper portion 27a by the long groove portion 1.
b, which serves as a guide when press-fitting into
27a2 serves as a guide for pulling out the stopper 27a from the long groove 1b.

That is, FIG. 6B which is a view taken in the direction of arrow A in FIG.
As shown in FIG. 5, when the stopper 27a is press-fitted into the long groove 1b, the first taper 27a1 is called in by applying a force in the direction of the arrow b, and the long groove 1b expands, and after the press-fitting, the long groove expands. 1b can be easily mounted by elastically returning. Stopper part 27 after assembly
a is located at the position shown by the broken line in FIG. 6B, and functions as a stopper for the stacking tray 1 by the surface 27a3 (see FIG. 1).

On the other hand, when the stopper portion 27a is disassembled from the loading tray 1, as shown in FIG. 6C, the second tapered portion 27a2 is called into the long groove portion 1b (see FIG. 1). After the taper direction of the second taper 27a2 is perpendicular to the long groove 1b), a force in the direction of arrow c is applied to the link member 27, so that the long groove 1b is expanded by the second taper 27a2. The portion 27a can be easily removed from the long groove portion 1b.

As described above, by providing the first tapered portion 27a1 and the second tapered portion 27a2 on the stopper portion 27a, the link member 27 can be easily assembled and disassembled.

(Structure of Stacking Restriction Mark of Side Guide Member) Next, a description will be given of a mark structure for regulating the sheets S stacked on the stacking tray 1. FIG.

In the sheet feeding apparatus of the present embodiment,
As shown in FIGS. 1 and 7, two slidable side guide members 28 are provided for aligning the side edges of the sheets stacked on the stacking tray 1.
Is connected to a rack (not shown) by a pinion, and is slidably mounted so that the sheet S is set at the center position of the stacking tray 1 when both side guide members 28 abut on both side ends of the sheet. .

The upright sheet contact surface 28a of the side guide member 28 is provided with a through hole 28b for indicating the upper limit of the stacking height of the sheet S.
(See FIG. 7 (a).) This indicates that the sheet bundle may be stacked. FIG. 7B shows a state in which the sheet bundle is stacked on the stacking tray 1 when viewed from the inside of the side guide member 28, and FIG. 7C shows a state when viewed from the outside.

As described above, by providing the through-holes 28b in both side guide members 28 and indicating the loading height, it is clear how much the loading is performed with respect to the loading limit height H from all directions near full loading. Becomes Further, since it is not necessary to attach a seal or the like made of a material different from that of the side guide member 28 to indicate the loading limit as in the related art, the number of parts and the assembly process can be reduced, and the cost can be reduced. In the case of the separation of different materials, there is no need for a step of separating and separating the label as in the related art. Further, when the user slides the side guide member 28, the through hole 28b is located near the pinching portion (the sheet contact surface 28a), so that the stacking amount of the sheet bundle can be easily adjusted. ing.

Second Embodiment Next, another embodiment of the link configuration of the sensor flag 24 will be described with reference to FIG. FIG. 8 is a diagram illustrating a state in which the sheet stacking member according to the second embodiment is opened and closed, (a) is a state in which the sheet stacking member is opened, and (b) is an explanatory diagram illustrating a state in which the sheet stacking member is closed. The members having the same functions as those of the first embodiment are denoted by the same reference numerals.

The link configuration according to this embodiment is different from the link configuration of the first embodiment in that the link member linking the flag cover 26 as the holding member and the stacking tray 1 as the sheet stacking member is the same as the flag cover 26. The point is that they are integrally formed.

As shown in FIG. 8A, an arm 29 functioning as a link member is provided on the flag cover 26, and a boss 29a is provided at the tip thereof. On the other hand, the rib 30 provided integrally with the stacking tray 1 is formed with a long groove 30a, and the boss 29a is slidably engaged with the long groove 30a.

As can be seen from the state in which the stacking tray 1 is open in FIG. 8A and the state in which the stacking tray 1 is closed in FIG. Therefore, the same effect as in the first embodiment can be obtained. Further, even if the user attempts to lift the flag cover 26 in the direction of the arrow in FIG. 8A, the stacking tray 1 is lifted, so that no excessive force is applied to the apparatus.

Further, since the link member is integral with the flag cover 26, the flag cover 26 can be rotated more reliably when the loading tray 1 is opened and closed.

[Third Embodiment] Next, another embodiment of the structure of the lamination control sign of the side guide member will be described with reference to FIG. FIG. 9 is an explanatory diagram showing the configuration of the side guide member according to the third embodiment.

First, the side guide member 28 shown in FIG. 9A is different from that of the first embodiment in that a through-hole 28b as a sheet lamination regulation mark provided on the sheet contact surface 28a is provided on the contact surface 28.
This is the point provided up to the bottom of a. Thus, even when a small amount of the sheet S remains, it is possible to check the stacking amount from outside the side guide member 28.

The difference between the side guide member 28 of the first embodiment and the side guide member 28 in FIG.
Is that the sheet contact surface 28a is made of a transparent or translucent material. Thus, the stacking height of the sheet material can be easily confirmed from all directions.

[Other Embodiments] In the above-described embodiment, an example is shown in which the sheet feeding apparatus B is used for an electrophotographic laser beam printer. Of course, the present invention can be applied to an image forming apparatus using another recording method such as a recording method or a thermal transfer recording method.

As described above, the image processing means can be constituted not only by the image forming means but also by an image reading means. That is, the sheet feeding device B is also suitable for an image reading device in which a document is set as a sheet S, the document is separated and fed one by one, and the document reading information is read by image reading means as image processing means. Can be used.

[0051]

The present invention is constructed as described above.
Since the holding member that holds the sensor flag rotates in conjunction with opening and closing of the sheet stacking member, the sensor flag can be reliably set to the home position when the sheet stacking member is opened. Attempts to lift the flag also prevent the sheet stacking member from lifting at the same time and applying a force that deforms the sensor flag.

A stopper portion is provided at one end of the link member to be inserted and locked in a groove formed in the sheet stacking member, and a first taper portion serving as a guide when the stopper is pressed into the groove. And the provision of the second tapered portion, which serves as a guide when the stopper portion is pulled out from the groove portion, facilitates press-fitting and pulling-out of the link member, and facilitates assembly and disassembly of the device. .

Further, the sheet stacking member is provided with a slidable side guide member for positioning the side end of the placed sheet, and a through hole is provided in a sheet contact surface of the side guide member, or the sheet contact member is provided with a through hole. By configuring the surface with a transparent or translucent material, the sheet stacking restricted position can be easily confirmed.

[Brief description of the drawings]

FIG. 1 is an explanatory perspective view showing a main part of a sheet feeding apparatus.

FIG. 2 shows a state when a sheet stacking member is opened and closed,
(a) is an explanatory view showing a state where the sheet stacking member is opened, and (b) is an explanatory view showing a state where the sheet stacking member is closed.

FIG. 3 is an overall schematic explanatory view of an image forming apparatus using a sheet feeding device.

FIG. 4 is an explanatory cross-sectional view showing a separation feeding configuration.

FIG. 5 is a perspective explanatory view showing a configuration in which a sheet is pressed against and separated from a pickup roller.

FIG. 6 is an explanatory diagram of a configuration of a link member.

FIG. 7 is an explanatory diagram of a sheet stacking restriction marker of a side guide member.

FIGS. 8A and 8B are explanatory diagrams illustrating a state when the sheet stacking member according to the second embodiment is opened and closed, where FIG. 8A illustrates a state where the sheet stacking member is opened and FIG. 8B illustrates a state where the sheet stacking member is closed. is there.

FIG. 9 is an explanatory diagram showing a configuration of a side guide member according to a third embodiment.

FIG. 10 is an explanatory diagram of a sheet feeding device according to a conventional example.

FIG. 11 is an explanatory diagram of a sheet detection configuration and a stacking restriction sign according to a conventional example.

[Explanation of symbols]

 A: Laser beam printer B: Sheet feeding device S: Sheet 1: Loading tray 1a: Shaft 1b: Long groove 2: Conveying roller pair 3: Guide path 4: Image forming means 5: Photoconductor drum 6: Laser scanner 7: Transfer roller 8 ... Fixing roller pair 9, 10 ... Discharge roller pair 11 ... Guide path 12 ... Discharge part 13 ... Feeding plate 13a ... Loading surface 13b ... Tube part 13c ... Stopper 13d ... Separation sheet material 13e ... Through hole 14 ... Pickup Roller 15 ... Separation pad 16 ... Separation spring 17 ... Support shaft 18 ... Feeding spring 19 ... Roller shaft 20 ... Cam 21 ... Rotating shaft 22 ... Lever 22a ... Hole 22b ... Groove 23 ... Shaft 24 ... Sensor flag 24a ... Flag Portion 24b Probe portion 24c Rod portion 25 Photointerrupter 26 Flag cover 27 Link member 27a Stopper portion 27a1 First taper portion 27a2 Second taper portion 27a3 Surface 27b ... shaft portion 28 ... side guide member 28a ... seat contact surface 28b ... through hole 29 ... arm 29a ... boss portion 30 ... rib 30a ... long groove

Claims (6)

[Claims] 1. A sheet feeding device for separating and feeding a set sheet, comprising: a sheet stacking member which can be opened and closed with respect to an apparatus main body and on which a sheet can be stacked; and a sheet stacked on the sheet stacking member. A sheet flag that is rotated by the rotation of the sheet, a holding member that rotatably holds the sheet flag, a link member that connects the holding member and the sheet stacking member, and a feeding rotator that applies a feeding force to the sheet. And a sheet feeding device, wherein the holding member is configured to rotate in conjunction with an opening / closing operation of the sheet stacking member. 2. A stopper portion, which is provided at one end of the link member and is inserted and locked into a groove formed in the sheet stacking member, and serves as a guide when the stopper is pressed into the groove. 2. The sheet feeding device according to claim 1, further comprising a second tapered portion serving as a guide when the stopper is pulled out from the groove. 3. The sheet feeding device according to claim 1, wherein the link member is formed integrally with the holding member. 4. A sheet feeding device for separating and feeding a set sheet, comprising: a sheet stacking member which can be opened and closed with respect to the main body of the apparatus and on which a sheet can be stacked; and a sheet stacked on the sheet stacking member. A sheet feeding device, comprising: a slidable side guide member for positioning a side end; and a through hole provided in a sheet contact surface of the side guide member. 5. A sheet feeding device for separating and feeding a set sheet, comprising: a sheet stacking member which can be opened and closed with respect to the main body of the apparatus and on which a sheet can be stacked; and a sheet stacked on the sheet stacking member. A sheet feeding device, comprising: a slidable side guide member for positioning a side end; and a sheet contact surface of the side guide member made of a transparent or translucent material. 6. A sheet feeding device according to claim 1, which feeds a sheet, and reads an image written on the sheet fed by the sheet feeding device. Or an image processing means for forming an image on the fed sheet.