JPH08268581A - Sheet supply device - Google Patents

Abstract

PURPOSE: To bring a sending-out roller into contact with a fixed position regardless of a stacking quantity of sheets. CONSTITUTION: A sending-out roller 24 arranged in an intermediate part of a shaft 76 is opposed to a tip part of master paper 12 housed in a cassette 20 by being stacked. A shaft is inserted into guide holes 82 vertically formed to a surface of the master paper in side plates 72 and 74, and a pinion gear 84 meshing with a clutch gear 86 is installed through a one-way clutch 88, and moves upward by integrally rotating with the pinion gear in the opposite direction of the arrow B direction. A one-way clutch 80 is arranged between the shaft and the sending-out roller, and the sending-out roller moves downward in the vertical direction to a surface of the master paper while rotating by arrow B directional rotation of the shaft, and comes into contact with a fixed position regardless of a stacking quantity of master paper.

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 which feeds a sheet from a storage container by bringing a delivery roller into contact with the sheet stored in the storage container.

[0002]

2. Description of the Related Art In the field of light printing, a photosensitive material having a photoconductive layer composed of zinc oxide and a resin formed on the surface of a paper support (for ease of plate making, speediness, and reduction of plate making cost) (Hereinafter referred to as "master paper") is used.

In a photoengraving apparatus for making a printing plate using this master paper, the master paper stored in a cassette or the like in which a large number of sheets are stacked is pulled out one by one from the cassette, and the master paper is electrically charged. A toner image is formed on the surface of the master paper by performing exposure, development, and heat fixing processing in this order. By etching the master paper on which the toner image is formed with this photolithography apparatus, a printing plate can be obtained in which the photosensitive layer portion to which toner is not attached has hydrophilicity.

In such a photomechanical system, it is necessary to avoid adverse effects from a conveyance guide or the like on the surface of the master paper on which the electrostatic latent image is formed. It is designed to convey paper, and the cassette installed in the photoengraving machine
Master paper is stacked and stored with the photosensitive layer facing upward.

The sheet feeding mechanism for feeding the master paper used in such a photoengraving apparatus from the cassette to the inside of the apparatus is the uppermost master paper among the stacked master papers like the sheet feeding mechanism of a copying machine or the like. The delivery roller is pressed and the master paper is delivered from the cassette by the frictional force generated between the delivery roller and the surface of the master paper when the delivery roller is rotationally driven.

On the other hand, in the photomechanical system, when the master paper is nipped and conveyed by the pair of conveyance rollers in the exposure section, if the conveyance by the delivery rollers for ejecting the master paper from the cassette continues, the conveyance speed of the master paper in the exposure section May become unstable and uneven exposure may occur.Therefore, the delivery roller should be brought into contact with the surface of the master paper until the master paper is nipped by the pair of transport rollers in the exposure section. After the master paper is nipped, the upper roller of the feed roller pair is made to contrast upward. Generally, the moving mechanism of the sending roller has a shaft of the sending roller attached to one end of a pair of arms,
A mechanism is used that rotates the pair of arms around the other ends of the pair of arms to move the delivery roller up and down.

[0007]

However, when the delivery roller is moved up and down by pivoting about the other ends of the pair of arms, the contact position of the delivery roller with respect to the master paper changes depending on the amount of the stacked master papers. Resulting in. For this reason, when the remaining amount of the master paper stored in the cassette becomes small, the delivery roller is placed on the portion of the master paper where the electrostatic latent image is formed, not at the tip of the master paper where the electrostatic latent image is not formed. Sometimes. The delivery roller comes into contact with the portion where the electrostatic latent image is formed, and rubbing marks are left on the master paper due to the pressing force and frictional force of the delivery roller, and uniform charging cannot be performed, and recording is performed. There is a problem that it adversely affects the toner image.

The present invention has been made in consideration of the above facts, and feeds out a sheet by bringing a feeding roller into contact with a fixed position of the uppermost sheet regardless of the amount of stacked sheets with a simple structure. An object of the present invention is to provide a sheet feeding device capable of performing the above.

[0009]

The invention according to claim 1 is
A sheet feeding device for feeding and feeding a sheet from a storage container by rotation of a delivery roller in contact with a sheet stored in the storage container, and supporting means for rotatably supporting the delivery roller and downward movement of the supporting means by its own weight. And an elevating means for moving the supporting means upward and separating the delivery roller from the sheet by rotatably supporting the movable supporting means.

According to a second aspect of the present invention, there is provided the sheet feeding device according to the first aspect, in which the driving means for rotationally driving the supporting means and the driving means provided between the feeding roller and the supporting means move from the supporting means to the supporting means. When the rotational driving force in one direction is applied, the rotational driving force is transmitted from the supporting means to the feed roller, and when the rotational driving force in the other direction is applied from the driving means to the feeding roller, the rotational driving force is applied from the supporting means. First clutch means that does not transmit to the delivery roller, and support so that the support means is moved upward when the drive means is provided between the support means and the elevating means and the rotational drive force in the other direction is applied to the support means. Second clutch means for transmitting the rotational driving force from the means to the elevating means, and not transmitting the rotational driving force from the supporting means to the elevating means when the driving means applies the rotational driving force in the one direction to the elevating means, Including It is characterized in.

[0011]

According to the first aspect of the present invention, the feeding roller can be moved upward in the direction perpendicular to the surface of the sheet by the elevating means. Further, when the sheet stored in the storage container is delivered, the delivery roller can be moved downward along the guide means in the direction perpendicular to the surface of the sheet along with the support means to bring the delivery roller into contact with the surface of the sheet.

Further, even if the stacking amount of the sheets is changed, the feeding roller can be brought into contact with a fixed position of the uppermost sheet among the stacked sheets. Further, since the driving force is not applied when the delivery roller moves downward, unnecessary pressure is not applied to the sheet when the delivery roller contacts the sheet. At this time, if the downward movement force of the supporting means and the feeding roller is adjusted by the urging means or the like that gives an upward urging force, the feeding roller can press the sheet with a desired pressing force.

According to the second aspect of the present invention, when the driving means rotates the supporting means in the sheet feeding direction of the feeding roller, the rotational driving force of the supporting means is transmitted to the feeding roller via the first clutch means. The feeding roller rotates integrally with the supporting means, and the rotational driving force of the supporting means is not transmitted to the elevating means via the second clutch means, and the supporting means moves downward together with the feeding roller without the rotational driving force. When the delivery roller comes into contact with the sheet, the sheet is delivered and supplied to the next process.

When the support means rotates in the direction opposite to the sheet feeding direction of the feed roller, the rotational driving force of the support means is not transmitted to the feed roller via the first clutch means, and the feed roller and the support means are separated from each other. Due to the relative rotation, the sheet is neither pulled in nor delivered. At this time, the rotational driving force of the supporting means is transmitted to the elevating means via the second clutch means, the feeding roller is raised together with the supporting means, and the feeding roller can be smoothly separated from the sheet.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a schematic structure of a photolithography apparatus 10 to which this embodiment is applied. This photoengraving machine 1
0 is a master paper 1 having a photoconductive photosensitive layer formed of zinc oxide and resin on the surface of a paper support.
2 is used to create a printing plate for printing.

A loading port 16 is provided on one side wall (a side wall on the right side of the drawing in FIG. 1) of the casing 14 of the photoengraving apparatus 10.
Are formed. A cassette 20 in which the master papers 12 are stacked in a box 18 and housed in a light-shielded state is attached to the loading port 16. The box 18 is provided with a cover 18A.
And the cassette 20 is inserted into the loading port 16 so that one end of the master paper 12 housed inside is exposed inside the casing 14.

Inside the casing 14, inside the loading port 16, there is provided a paper feeding section 22 equipped with a sheet feeding device. The paper feed unit 22 is provided with a delivery roller 24 facing the leading end of the master paper 12 exposed from the loaded cassette 20, and the delivery roller 24 contacts a predetermined position on the surface of the master paper 12. The master papers 12 are rotated in contact with each other, and one of the stacked master papers 12 is fed into the apparatus one by one from the top. The master paper 12 is accommodated in a state where the photosensitive layer is directed upward, and is conveyed in the apparatus along the direction of arrow A with the photosensitive layer being directed upward.

Inside the casing 14, the charging section 26 and the printing section 2 are arranged in this order along the conveying direction of the master paper 12.
8, a developing unit 30 and a fixing unit 32 are provided. The side wall of the casing 14 adjacent to the fixing portion 32 has a discharge port 3
4 and a discharge tray 36 are provided.

The master paper 12 pulled out from the cassette 20 is guided by a guide 38 provided between the sheet feeding section 22 and the charging section 26, and a roller pair 40 of the charging section 26 is guided.
Is supplied between. In the charging section 26, the master paper 12 is nipped and conveyed by the roller pair 40 and uniformly charged by corona discharge of the charging device 42 or the like. As a result, the master paper 12 is sent to the printing unit 28 with the photosensitive layer on the upper surface thereof being negatively and uniformly charged. Baking part 28
Then, the master paper 1 by the roller pair 44, 46
2 is clamped and conveyed at a constant speed. This roller pair 44,
The space between 46 is the printing position of the master paper 12, and when passing between the roller pairs 44 and 46,
It is exposed by light emitted from above.

On the other hand, a printing optical section 48 is arranged on the upper portion of the casing 14. In this printing optical unit 48,
A manuscript table 52 provided on the upper surface of the casing 14 and provided with transparent glass on which the manuscript 50 is placed, and a cover for holding the manuscript 50 between the manuscript table 52 and the manuscript table 52 so that the upper surface of the manuscript table 52 can be opened. 54 is provided. An optical system 58 including a light source 56 that emits slit-shaped light, a reflection mirror, a rod lens, and the like is provided inside the casing 14 and below the document table 52.

In the printing optical section 48, light is emitted from a light source 56 toward a document 50 on which a document image is recorded, and the light reflected from the document 50 according to the recorded image is paired by an optical system 58 with a roller pair. The space between 44 and 46 is irradiated from above to form an image on the master paper 12 passing between the pair of rollers 44 and 46, and the document image recorded on the document 50 is printed on the master paper 12. At this time, in the printing optical unit 48, the document table 52 is moved in synchronization with the conveyance of the master paper 12 to move the document 5 to the master paper 12.
The so-called slit exposure for printing the original image recorded at 0 is performed. The method of printing the image on the master paper 12 is not limited to this, and various methods can be used for printing.

In the master paper 12, the photosensitive layer in the portion exposed to the light becomes conductive and the negative charge is lost, and the negative charge remains in the portion not exposed to the light. As a result, an electrostatic latent image corresponding to the image recorded on the original 50 is formed on the master paper 12.

The master paper 12 that has been baked in the baking section 28 is then sent to the developing section 30. In the developing unit 30, the master paper 12 is fed by the roller pair 60.
, And a developer containing colored toner particles is uniformly applied to the upper surface of the master paper 12, and then the unnecessary developer is removed from the surface of the master paper 12 by the squeeze roller 62. At this time, for example, positively charged toner particles are used as the toner particles contained in the developer, and when the toner particles are applied to the surface of the master paper 12, they are adsorbed by the negative charge on the surface of the master paper 12, A toner image corresponding to the electrostatic latent image is formed on the surface of the master paper 12.

In the fixing section 32, a guide plate 68 is provided between the roller pairs 64 and 66, and a heater 70 is arranged above the guide plate 68. When the master paper 12 on which the toner image is formed moves on the upper surface of the guide plate 68 while being nipped and conveyed by the roller pairs 64 and 66, the heat of the heater 70 causes a predetermined temperature (for example, 50 °).
When heated to about C to 80 ° C.), the toner particles adsorbed on the surface are fused.

Master paper 12 which has been fixed
Is discharged from the discharge port 34 to the discharge tray 36. In this way, the master paper 12 on which the toner image corresponding to the image recorded on the original 50 is formed is chemically treated (etched) to make the photosensitive layer without the toner hydrophilic to print. It is used as a printing plate for ink offset printing.

By the way, as shown in FIGS. 3 and 4, the shaft 76, which is stretched between the pair of side plates 72 and 74, is provided at the axial center of the delivery roller 24 provided in the paper feeding unit 22. It has been inserted. A bearing 78 (see FIGS. 2 and 3) is arranged between the delivery roller 24 and one end of the delivery roller 24 in the axial direction, and the delivery roller 24 is rotatably connected to and supported by the shaft 76. There is.
Further, as shown in FIGS. 3 and 4, the delivery roller 24
A one-way clutch 80 forming a first clutch means is provided between the other end of the shaft direction and the shaft 76.

In the one-way clutch 80, when the shaft 76 rotates in the feeding direction of the master paper 12 (direction of arrow B in FIGS. 2 and 3), the shaft 76 and the feeding roller 24 are engaged with each other so that the feeding roller 24 moves. Shaft 7
When the shaft 76 rotates in the direction opposite to the arrow B, the engagement between the shaft 76 and the delivery roller 24 is released so that the delivery roller 24 can rotate relative to the shaft 76. There is.

On the other hand, as shown in FIGS. 2 and 3, each of the pair of side plates 72, 74 is provided with a long guide hole 82 along the direction perpendicular to the surface of the master paper 12 accommodated in the cassette 20. Formed, shaft 7
Both ends of 6 are inserted into the guide holes 82 so that the shaft 76 can move along a direction perpendicular to the surface of the master paper 12. Also, each side plate 7
A pinion gear 84 is attached to the tip of the shaft 76 protruding from the reference numerals 2, 74. These pinion gears 84 are attached to the side plates 7 along the guide holes 82.
It is meshed with a rack gear 86 attached to the 2, 74.

Between the pinion gear 84 and the shaft 76, the one-way clutch 8 serving as a second clutch means.
8 are provided. This one-way clutch 88
When the shaft 76 rotates in the direction opposite to the direction of feeding the master paper 12 by the feeding roller 24 (the direction opposite to the arrow B direction), the shaft 76 and the pinion gear 84.
And are engaged with each other to rotate integrally, and when the shaft 76 rotates in the direction of arrow B, the engagement is released to allow relative rotation.

Therefore, when the shaft 76 rotates in the direction opposite to the arrow B direction, the pinion gear 84 is moved to the rack gear 8
6 is moved upward while meshing with 6 to move the feeding roller 24 upward together with the shaft 76. As a result, the delivery roller 24 is separated from the surface of the master paper 12. Further, the one-way clutch 88 releases the engagement between the pinion gear 84 and the shaft 76 when the shaft 76 rotates in the direction of arrow B so that the pinion gear 84 can rotate relative to the shaft 76. In this state, the weight of the shaft 76, the delivery roller 24, and the like acts on the pinion gear 84, so that the pinion gear 84 moves downward along the rack gear 86, and the delivery roller 24
Is brought close to the surface of the master paper 12 and brought into contact therewith.

The loading position of the cassette 20 and the position of the guide hole 82 are set so that the delivery roller 24 comes into contact with the outside of the image printing area in the printing section at the leading end of the master paper 12 in the transport direction. .

On the other hand, an intermediate portion of the shaft 76 rotatably penetrates a bracket 90 arranged between the feed roller 24 and the side plate 74. The bracket 90 has a guide roller 9 loosely fitted in the guide hole 82 of the side plate 74.
2 (see FIGS. 3 and 4) is provided, and the shaft 7
6 and 6 can be moved up and down along the guide hole 82.

The bracket 90 is provided with a motor 94 which is a driving means, and a gear 96A attached to the rotating shaft 94A of the motor 94 and a gear 96B attached to the shaft 76 mesh with each other. For this reason,
The shaft 76 is rotationally driven in the arrow B direction or in the direction opposite to the arrow B direction by the rotational driving of the motor 94.

Therefore, when the shaft 76 is in the standby position at the upper end of the guide hole 82 and the shaft 76 is rotated in the direction of arrow B by the drive of the motor 94, the shaft 7 is rotated.
6 rotates the delivery roller 24 and moves downward by the weight of the shaft 76, the delivery roller 24, etc. to bring the delivery roller 24 into contact with a predetermined position on the surface of the master paper 12 and deliver the master paper 12 from the cassette 20. . Also, stacked master paper 12
When the shaft 76 rotates in the direction opposite to the arrow B direction from the position where the delivery roller 24 is in contact with the uppermost surface of the master paper 12 by the reverse driving of the motor 94, the rotation of the delivery roller 24 is stopped and , The rotational force is transmitted to the pinion gear 84, and the pinion gear 84
Moves upward while meshing with the rack gear 86, and the feeding roller 24 separates from the surface of the master paper 12.

The shaft 76 is attached to the delivery roller 24.
A counterweight 98 is provided between the side plate 72 and the side plate 72 so that the pressing force is not partially changed when the delivery roller 24 comes into contact with the master paper 12 due to the weight of the motor 94 or the like. Further, the bracket 90 is biased upward by a biasing means such as the tension coil spring 100, so that when the delivery roller 24 contacts the surface of the master paper 12,
The master paper 12 is prevented from being pressed more than necessary.

Next, the operation of this embodiment will be described. In the photoengraving apparatus 10, the master paper 12 is loaded by inserting the front end portion of the cassette 20 accommodating a large number of master papers 12 in a stack from the insertion port 16. After that, the photo processing apparatus 10 starts the process when the document 50 is placed on the document table 52 and a start switch (not shown) is operated.

In the photoengraving apparatus 10, when the processing is started, the master paper 12 contained in the cassette 20 is sent out from the cassette 20 by the sending roller 24,
It is supplied to the charging unit 26. In the charging section 26, the master paper 12 is drawn in by the roller pair 40, uniformly charged by the charger 42, and then sent out to the printing section 28. In the printing unit 28, the surface of the master paper 12 is irradiated with the light reflected according to the image recorded on the original 50, and the original 5 is printed.
An electrostatic latent image corresponding to the image recorded in 0 is formed.

On the other hand, in the developing unit 30, unnecessary toner is removed after applying a developer containing charged toner particles on the surface of the master paper 12 on which the electrostatic latent image is formed,
A toner image corresponding to the electrostatic latent image is formed on the surface of the master paper 12. In the next fixing section 32, the toner particles on the surface of the master paper 12 on which the toner image is formed are heated by the heat generated from the heater 70 and fixed on the surface of the master paper 12.

The master paper 12 on which the toner image is formed in this manner is subjected to an etching treatment,
It is used as a printing plate in offset printing for creating a printed matter according to the image recorded on the original 50.

By the way, the delivery roller 24 is retracted above the tip of the master paper 12 stored in the cassette 20, and when the processing is started, the motor 94 is driven to move the shaft 76 in the direction of arrow B. Drive to rotate. When the shaft 76 rotates in the direction of arrow B, the delivery roller 24
The one-way clutch 80 provided between and the shaft 76
And the delivery roller 24 are engaged with each other and integrally rotated.

On the other hand, since the one-way clutch 88 provided between the shaft 76 and the pinion gear 84 releases the engagement between the shaft 76 and the pinion gear 84, the pinion gear 84 rotates relative to the shaft 76 in the direction of arrow B. It becomes possible, and the shaft 7 which depends on the pinion gear 84
6 and the weight of the feed roller 24, etc.
4 moves downward while meshing with the rack gear 86.

The shaft 76 is moved downward along the guide hole 82 by the downward movement of the pinion gear 84, and the delivery roller 24 is vertically approached to the surface of the master paper 12. At this time, since the bracket 90 is urged upward by the tension coil spring 100, the weight of the pinion gear 84 is light, the delivery roller 24 is gently lowered, and the delivery roller 24 is moved by the master paper 1.
Even when it comes into contact with 2, the master paper 12 is applied with a weight more than necessary and pressed, and the rubbing traces remain on the master paper 12 due to the rotation of the delivery roller 24, so that the master paper 12 cannot be uniformly charged. It does not affect the recorded toner image in blue.

Since the rotating force is transmitted from the shaft 76 to the delivery roller 24 in contact with the surface of the master paper 12, the delivery roller 24 is placed on the surface of the uppermost master paper 12 among the stacked master papers 12. When contacted, the master paper 1
2 is sent out from the cassette 20. At this time, the delivery roller 24 moves vertically downward with respect to the surface of the master paper 12 and comes into contact with the surface of the master paper 12. Therefore, even if the stacking amount of the master paper 12 is different,
The master paper 12 stacked and accommodated in the cassette 20 comes into contact with a predetermined position. As a result, the master paper 12 receives the rotational force of the delivery roller 24 and the cassette 2
It is sent out from 0.

When the rotating delivery roller 24 is brought into contact with the master paper 12 and the master paper 12 is delivered from the cassette 20, the greatest force is received from the delivery roller 24 when the master paper 12 starts moving. That is, the master paper 12 is the delivery roller 24.
Is pressed most strongly from the surface, and a large frictional force acts on the surface of the master paper 12.

If a large frictional force is applied when the master paper 12 is sent out from the cassette 20, a rubbing mark of the sending roller 24 will be generated on the surface of the master paper 12 and when the master paper 12 is charged, that portion will be generated. Uneven charging may occur, which adversely affects the electrostatic latent image formed on the printing unit 26.

On the other hand, in the paper feeding unit 22 of this embodiment, the position where the delivery roller 24 contacts the master paper 12 is set outside the area where the image is formed, and further, the stacking amount of the master paper 12 is different. The contact start position of the delivery roller 24 on the master paper 12 does not shift. In addition to this, since the driving force is not transmitted from the shaft 76 to the pinion gear 84 when the feeding roller 24 is moved downward, an excessive force is applied to the master paper 12 via the feeding roller 24. There is no. Therefore, when the master paper 12 is fed, the pressing force and the frictional force applied by the feed roller 24 do not adversely affect the image recorded on the master paper 12, and it is possible to produce a high-quality printing plate.

The present embodiment described above is an example of the present invention and does not limit the structure of the present invention. For example, in the present embodiment, the raising and lowering and rotation of the feed roller 24 are performed by driving the same motor 94, but they may be driven by different driving sources. Further, although one delivery roller 24 is disposed on the shaft 76 in the description, it is of course possible to dispose a plurality of delivery rollers, and of course, various shapes having protrusions or the like are provided depending on the material of the sheet to be taken out. It is also possible to use a roller.

In the present embodiment, the shaft 76 generated by attaching the motor 94 or the like to the shaft 76.
Although the unbalance of the weight along the axial direction of the pinion was adjusted by the counterweight 98 and the like, the weight of the pinion gear 84 can be adjusted by various methods such as using a constant torque spring in the vicinity of the bracket 90. .

Further, the present invention can be applied not only to the master paper 12 but also to various sheet feeding devices for feeding sheet-shaped members such as films and photographic papers as well as paper and the like to the photoengraving apparatus 10. The present invention is not limited to this, and can be used in a processing device corresponding to a sheet, such as a copying machine that uses paper as a sheet, a facsimile, or the like.

[0050]

As described above, in the present invention, the feeding roller is moved in the vertical direction with respect to the surface of the sheet to be brought into contact with and separated from the surface of the sheet with a simple structure. The delivery roller can be reliably brought into contact with a fixed position of the uppermost sheet.

Further, according to the present invention, with the simple construction using the single driving means and the first and second clutch means, the rotation and the vertical movement of the feeding roller in the sheet feeding direction can be surely performed. Has excellent effect.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a photoengraving apparatus applied to this embodiment.

FIG. 2 is a side view of essential parts showing a paper feeding unit of the photoengraving apparatus.

FIG. 3 is a perspective view of a main part of a paper feeding unit showing the vicinity of a delivery roller.

FIG. 4 is a front view of a main part of the vicinity of a delivery roller as seen from the upstream side in the master paper conveyance direction.

[Explanation of symbols]

 10 Photographic Plate Making Machine 12 Master Paper (Sheet) 20 Cassette 22 Paper Feeding Section 24 Delivery Roller 76 Shaft (Supporting Means) 80 One-Way Clutch (First Clutch Means) 82 Guide Hole 84 Pinion Gear (Elevating Means) 86 Rack Gear (Elevating Means) 88 one-way clutch (second clutch means) 94 motor (driving means)

Claims (2)

[Claims] 1. A sheet feeding device for feeding and feeding a sheet from a storage container by rotation of a feeding roller in contact with a sheet stored in the storage container, the support means rotatably supporting the delivery roller; A sheet feeding device comprising: an elevating unit that supports the sheet so that it can be moved downward by its own weight, and that the supporting unit is moved upward by transmitting the rotational driving force to separate the delivery roller from the sheet. 2. A drive means for rotationally driving the support means, and a rotary drive force provided from the drive means when the drive means is provided between the feed roller and the support means to give a one-way rotary drive force to the support means. Between the support means and the elevating means, the first clutch means is transmitted to the delivery roller and does not transmit the rotational drive force from the support means to the delivery roller when the drive means applies the rotational drive force in the other direction to the support means. The driving means transmits the rotational driving force to the elevating means so that the supporting means moves upward when the driving means applies the rotational driving force in the other direction to the supporting means. The sheet feeding device according to claim 1, further comprising: second clutch means that does not transmit the rotational driving force from the supporting means to the elevating means when the rotational driving force in one direction is applied.