JP3361417B2 - Double-sided paper feeder - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a double-sided sheet feeding device used in an image forming apparatus, and more particularly, to an ordinary sheet feeding tray and a double-sided unit which are integrally provided in a stacked state and which are common to both sheets. The present invention relates to a small-sized double-sided sheet feeding device having means.

[0002]

2. Description of the Related Art In an image forming apparatus having a double-sided sheet feeding function for forming images on both sides of a sheet, for example, an ordinary sheet feeding tray is attached to the bottom of a main body to temporarily receive the sheet on which an image is formed. Generally, a re-feeding device (double-sided unit) that feeds the paper toward the image forming unit again to form an image on the other surface is independently provided in the upper space of the paper feeding tray. However, with this configuration,
In particular, a space is required in the height direction, which does not meet the recent needs for downsizing and cost reduction. Therefore, as described above, the applicant of the present invention has proposed a large number of small-sized double-sided sheet feeding devices which are provided integrally with a normal sheet feeding tray and a double-sided unit in a laminated state and have a sheet feeding means common to both. .

[0003]

However, even in the above-mentioned double-sided sheet feeding device, if the feeding means has a pickup function, a retracting mechanism, etc., and the separating means is also included, it is more expensive. is there. Further, when the sheet bundle with the image formed on one side is transported to the re-feed position, there is a problem with the reliability of the curled sheet (because there is no member for surely pressing the leading edge of the sheet during the transportation).

[0004]

A first object of the present invention is to provide a double-sided sheet feeding device capable of improving the space efficiency of the double-sided unit.

A second object of the present invention is to provide a double-sided sheet feeding device capable of coping with various sizes of papers by the separation claws interlocking with the lateral movement of the side fence.

A third object of the present invention is to push out the rear end of a sheet bundle when it is transferred, to improve the reliability of the transfer, and to control both drive states freely by one drive means. Another object of the present invention is to provide a double-sided sheet feeding device that can reduce costs.

A fourth object of the present invention is to provide a double-sided sheet feeding device capable of surely guiding the front end of a bundle of sheets to the separating claw by the guide member and improving the reliability during transfer. It is in.

A fifth object of the present invention is to obtain a sheet feeding pressure force on both the sheet feeding tray side and the duplex unit side with one urging means, which can reduce the cost.
Another object of the present invention is to provide a double-sided sheet feeding device capable of preventing the interference of both separating claws.

[0010]

A sixth object of the present invention is to increase the margin for guiding and infiltrating the front end of the conveyed sheet bundle to the front end of the separation claw and further improving the reliability during the transfer. An object is to provide a double-sided sheet feeding device that can be used.

[0012]

A first object of the present invention is to provide a paper feed tray for accommodating paper sheets, a feeding means for feeding out paper sheets, and a separating claw which is in contact with both edges of the leading edge of the paper sheet on the movable bottom plate. Is placed in front of the paper feed tray, and the feeding
Separating means for separating and conveying the sheets of paper on the movable bottom plate sent out by the means , and above the paper feed tray,
In addition, in the space behind the feeding means, an intermediate tray for storing sheets of paper having an image formed on one side thereof, and a tip of a bundle of sheets once stored are supported, and can be moved forward and backward in the sheet re-feeding direction. Bei a duplex unit constituted by the movable bottom plate
The movable bottom plate is provided with separation claws, and the bundle of sheets stored in the intermediate tray and supported by the movable bottom plate is collectively transferred to the re-feeding position, and then also used as the feeding means. Double-sided paper feeding to the forming unit again
Device, which feeds paper from the paper feed tray located below.
When the paper is operating, the movable bottom plate is configured to retract upward.
This is achieved by the first means made.

The second purpose is to store paper.
A paper feed tray and a feeding means for feeding the paper,
The separation claws that contact both edges of the leading edge of the paper on the movable bottom plate
It is placed in front of the paper tray and is fed by the feeding means.
Separately transporting the sheets on the movable bottom plate one by one
Separation means, above the paper feed tray, and above the feeding
In the space behind the means, place a sheet of paper with an image on one side.
An intermediate tray for storing and a stack of sheets once stored.
Movable bottom plate that supports the leading edge and can move forward and backward in the refeed direction
And a duplex unit constituted by the movable bottom plate
A separation claw is provided on the
The stack of paper supported by the movable bottom plate
After the transfer to the storage, the image forming unit also serves as the feeding means.
Is a double-sided paper feeding device
Equipped with a movable side fence to align both edges of the paper
Reinstall the separation claw against the movable side fence.
This is achieved by the second means provided so as to be movable in the front-back direction of the sheet feeding direction .

The third purpose is to store paper.
A paper feed tray and a feeding means for feeding the paper,
The separation claws that contact both edges of the leading edge of the paper on the movable bottom plate
It is placed in front of the paper tray and is fed by the feeding means.
Separately transporting the sheets on the movable bottom plate one by one
Separation means, above the paper feed tray, and above the feeding
In the space behind the means, place a sheet of paper with an image on one side.
An intermediate tray for storing and a stack of sheets once stored.
Movable bottom plate that supports the leading edge and can move forward and backward in the refeed direction
And a double-sided unit configured by
A separation claw is provided on the
The stack of paper supported by the movable bottom plate
After the transfer to the storage, the image forming unit also serves as the feeding means.
If you are using a double-sided
Align the rear edge of the stack of paper stored in the intermediate tray, and
Movable to push out the end of the stack of sheets to a position where it can be re-fed
Equipped with a movable end fence, the movable bottom plate can be moved easily.
This is achieved by the third means which is driven by the movement of the movable end fence and is connected to the movable end fence .

The fourth purpose is to store paper.
A paper feed tray and a feeding means for feeding the paper,
The separation claws that contact both edges of the leading edge of the paper on the movable bottom plate
It is placed in front of the paper tray and is fed by the feeding means.
Separately transporting the sheets on the movable bottom plate one by one
Separation means, above the paper feed tray, and above the feeding
In the space behind the means, place a sheet of paper with an image on one side.
An intermediate tray for storing and a stack of sheets once stored.
Movable bottom plate that supports the leading edge and can move forward and backward in the refeed direction
And a double-sided unit configured by
A separation claw is provided on the
The stack of paper supported by the movable bottom plate
After the transfer to the storage, the image forming unit also serves as the feeding means.
Is a double-sided paper feeding device
When moving the stack of paper to a position where
And guide both ends of the leading edge of the paper to the separation claw.
This is accomplished by a fourth means that includes a guide member for sneaking into the separation pawl .

The fifth purpose is to store paper.
A paper feed tray and a feeding means for feeding the paper,
The separation claws that contact both edges of the leading edge of the paper on the movable bottom plate
It is placed in front of the paper tray and is fed by the feeding means.
Separately transporting the sheets on the movable bottom plate one by one
Separation means, above the paper feed tray, and above the feeding
In the space behind the means, place a sheet of paper with an image on one side.
An intermediate tray for storing and a stack of sheets once stored.
Movable bottom plate that supports the leading edge and can move forward and backward in the refeed direction
And a double-sided unit configured by
A separation claw is provided on the
The stack of paper supported by the movable bottom plate
After the transfer to the storage, the image forming unit also serves as the feeding means.
If you are using a double-sided
The protruding bottom is provided on the bottom of the movable bottom plate to
The urging of the pressing force to the movable bottom plate,
Do this by using the pressure mechanism of the bottom plate of the paper feed tray
This is achieved by the fifth means.

The fourth object is, in the second means,
When transferring the stack of paper to a position where
Guides the edge and guides both edges of the paper to the separation claw
This is achieved by the sixth means which has a guide member for sneaking into the separating claw .

The fifth purpose is to store paper.
A paper feed tray and a feeding means for feeding the paper,
The separation claws that contact both edges of the leading edge of the paper on the movable bottom plate
It is placed in front of the paper tray and is fed by the feeding means.
Separately transporting the sheets on the movable bottom plate one by one
Separation means, above the paper feed tray, and above the feeding
In the space behind the means, place a sheet of paper with an image on one side.
An intermediate tray for storing and a stack of sheets once stored.
Movable bottom plate that supports the leading edge and can move forward and backward in the refeed direction
And a double-sided unit configured by
A separation claw is provided on the
The stack of paper supported by the movable bottom plate
After the transfer to the storage, the image forming unit also serves as the feeding means.
If you are using a double-sided
A first bottom plate that supports paper and a
A lower second bottom plate is provided, and pressure is applied between these two bottom plates.
While holding the spring means for urging the force,
Paper can be fed by raising and lowering the second bottom plate.
Move the paper to the active position and retract it
Providing a protruding bottom on the bottom surface of the bottom plate allows
The urging of the pressing force to the moving bottom plate
This is accomplished by the seventh means which is also used as a pressing mechanism for the bottom plate of the lay .

The sixth object is, in the second means,
The separation claw is achieved by the eighth means provided so as to restrict the rotatable direction of the separation claw only in the upward direction.

[0020]

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

FIG. 1 is a perspective view showing a state in which the paper feed tray is pulled out from the main body of the image forming apparatus.

As shown in FIG. 1, an opening 1a is provided below the main body 1, and a paper feed tray 100 and a duplex unit 2 are provided.
00 has a two-stage structure that can be independently pulled out in a direction orthogonal to the sheet conveying direction. The feeding means 2 common to the paper feed tray 100 and the duplex unit 200 is schematically shown.

FIG. 2 is a block diagram of a double-sided sheet feeding device according to an embodiment of the present invention. In FIG. 2, the configuration of the entire unit and each unit will be described. As a whole configuration, the sheet feeding tray 100 is provided in the lower stage, the duplex unit 200 is provided in the upper stage, and the feeding means 2 (half-moon roller or the like) is provided above the front side of the sheet feeding tray 100 and in front of the duplex unit 200. It is arranged so that the feeding means 2 can be used both when the sheet is fed from the sheet and the sheet is re-fed from the duplex unit 200.

Next, the structure of each unit will be described.

First, the duplex unit 200 is supported by the tray guides 201 and 202, and the paper feed tray 100 is supported by the tray guides 101 and 102 so that it can be pulled out. The duplex unit 200 is a horizontal tray for storing an intermediate tray 200a for storing a predetermined number of sheets and a single-sided image-formed sheet 212a coming in from the direction A for reversing the intermediate tray 200a once. The transport path 204, the transport roller pair 203, and the horizontal transport path 204
A reversing roller 206 and a pressure roller 207 for reversing the sheet once at the front end portion of the reversing roller 20,
An auxiliary pressure roller 208 is provided at the lower end of the sheet 6 for reversing the sheet into the intermediate tray 200a from the direction B and reliably feeding the trailing edge of the sheet.

Further, the aligning mechanism aligns the rear end of the bundle of stored sheets 212 and the movable end fence 213 for sending the sheet forward in the sheet re-feeding direction, and aligns both side edges of the sheet. Is equipped with a movable side fence 205 (driven by a motor 216 or the like). Further, in front of the intermediate tray 200a, there is provided a movable bottom plate 211 that supports the leading end of the sheet stack 212 once stored and is capable of moving forward and backward in the sheet re-feeding direction to guide it to the sheet re-feeding position. The movable bottom plate 211 is provided with a separating claw 210 for pressing both sides of the leading edge of the sheet at the time of transfer and separating the sheets one by one at the time of re-feeding the both sides. It is rotatably supported by a claw arm 214 that is provided through the lower side of the movable side fence 205 and is slidably supported in the front-back direction of the re-feeding direction.

A guide member 209 is provided above the movable bottom plate 211 for guiding both side edges of the sheet from above and for causing the leading end of the sheet bundle 212 transferred to the separating claw 210 to go under. In this example, it is provided on the side fence). In addition, the movable bottom plate 211 is used for the intermediate tray 2.
A bottom plate arm 215 slidably provided in the lower side of 00a in the re-feeding direction is rotatably supported.

On the other hand, the paper feed tray 100 is provided with a first bottom plate 1 for stacking and supporting the already stacked paper stack 109.
05, and a second bottom plate 106 is provided below it,
A pressure spring 108 for urging a pressing force is sandwiched between the bottom plates 105 and 106. Further, a raising arm 107 connected to a raising motor 111 is provided below the second bottom plate 106, and by raising and lowering the second bottom plate 106, the upper surface position of the sheet bundle 109 is retracted from the paper feedable position. Switch to the position (the rise detecting means 3 is provided directly below the feeding means 2). Also, the paper feed tray 100
A separation claw 110 for separating the sheet bundle 109 one by one is provided in the front of the inside. The sheet bundle 109 is positioned by the side fence 104 and the end fence 103. Reference numeral 106a is a locking member provided on the second bottom plate 106.

FIG. 3 is a diagram showing the state of sheet feeding from the side of the sheet feed tray, and FIG. 4 is a diagram showing the state of sheet refeeding from the duplex unit side. First, as shown in FIG. 3, the paper feed tray 1
When feeding the paper from 00, the second bottom plate 106 is pushed up by the raising arm 107 connected to the raising motor 111. Then, the first bottom plate 105 supported by the pressure spring 108 and the sheet bundle 109 previously placed on the first bottom plate 105 rise to the sheet feedable position as the second bottom plate 106 rises, Feeding means 2 and separation claw 11
By 0, the uppermost paper is separated and conveyed in the C direction. Also,
The detection of the amount of bottom plate rise is performed by the rise detection means 3 provided directly below the feeding means 2. Further, the separation claw 110 is regulated in the upward direction by the locking member 106 provided on the second bottom plate 106.
a (separating claw tip 110a and locking member 106)
The pressure of the pressure spring 108 is received by a).

Here, the movable bottom plate 211 provided in the duplex unit 200 is pushed up by the protruding bottom portion 211a (details shown in FIG. 8) provided on the lower surface contacting the uppermost surface of the sheet stack 109 at point a. , Retreat upwards. On this occasion,
Since the tip 210a of the separation claw 210 hangs on the movable bottom plate 211 (self-weight), the separation claw 210 is interlocked and retracts upward. As a result, the space efficiency of the duplex unit 200 can be improved.

Further, in the embodiment of the present invention, it is possible to retract without a special retracting mechanism. Therefore, even when the protruding bottom portion 211a is not provided on the lower surface of the movable bottom plate 211, the same effect can be obtained by separately providing the retracting mechanism including the solenoid and the lever.

Now, returning to FIG. 2 again, the duplex unit 2
The stack operation to 00 will be described.

The sheet 212a on which the one-sided image has been formed enters the duplex unit 200 from the direction A, and the pair of conveying rollers 2
03, a conveying force is applied, the sheet passes through the horizontal conveying path 204, is inverted once by the reversing roller 206 and the pressure roller 207, and is conveyed by the pressure roller 207 located below to
Enter the intermediate tray 200a from the direction. At this time,
The movable end fence 213 preferably waits in advance at a position where the trailing edge of the sheet can be aligned. Further, the movable side fence 205 aligns both edges of the stored sheet bundle 212 (oblique lines). The above operation is repeated a predetermined number of times (a predetermined number of times) to complete the storage operation.

FIG. 5 is a block diagram for explaining the first stage operation (moving only the end fence) of transferring the sheet bundle stored in the intermediate tray to the re-feed position, and FIG. 6 is the same for the second stage. It is a block diagram for demonstrating operation | movement (movement of an end fence and a movable bottom plate). The paper feed tray 10 shown in FIG.
The first and second bottom plates 105 and 106 of the paper feed tray 100 are retracted before the paper feed state on the 0 side is changed to the repaper feed state on the duplex unit 200 side.

First, from the state shown in FIG. 2 where the storage is completed, the sheet bundle 212 is pushed out by the movable end fence 213 in the sheet re-feeding direction. Then, as shown in FIG. 5, the leading end of the sheet bundle 212 is moved to a position where the separation claw leading end 210a is hooked (at this point, the movable bottom plate 211 is in a stationary state). Here, by providing the guide member 209 on the upper side, it is possible to suppress the floating of the leading end of the sheet bundle and to make the separation claw leading end 210a surely slip into. The details of this operation will be described with reference to FIGS. 9 and 10.

The guide member 209 is preferably provided so as to slightly overlap the separation claw 210. Next, as a second step, the end fence 213 and the movable bottom plate 211 are moved at the same speed in the sheet re-feeding direction (D direction in FIG. 5). Then, when the movable bottom plate 211 is housed between the feeding means 2 and the sheet bundle 109 on the side of the sheet feed tray 100, the transfer of the sheet bundle 212 is completed (FIG. 6). At this time, the guide member 209
Although the leading edge of the sheet is separated from the tip of the separation claw 210a and the leading edge of the sheet bundle 212, it is possible to continuously guide the upper surfaces (points b) of both side edges of the sheet bundle 212 and suppress the floating (corrugation) of the sheet. .

FIG. 7 is a block diagram for explaining the re-feeding operation from the duplex unit. FIG. 7 is an enlarged view of the paper feeding unit in FIG. 4, and the re-feeding operation from the duplex unit 200 will be described below with reference to FIGS. From the state where the transfer of the bundle of sheets 212 is completed as shown in FIG. 6, the second bottom plate 106 is moved upward as in the case of feeding from the paper feed tray 100, and the sheets placed on the first bottom plate 105 are accordingly raised. The bundle 109 rises. Then, the uppermost sheet surface of the sheet bundle 109 comes into contact with the projecting bottom portion 211a of the movable bottom plate 211 at the point c, and the movable bottom plate 211 rises to a height at which it can be re-fed.
At this time, the rise detection means 3 controls the amount of rise. As a result, it is possible to use the feeding means 2 as well as the pressure spring 108 at the time of re-feeding from the duplex unit 200 and when feeding from the paper feed tray 100. In addition, the movable bottom plate 21 of the duplex unit 200
The sheet feeding pressure urging unit for 1 may be provided separately. At this time, the bottom plates 105 and 106 on the side of the paper feed tray 100 are retracted downward.

Next, details of the embodiments for each invention described in each claim will be described. FIG. 8 is a perspective view of the main part of the duplex unit. Since the side fence 205 and the separation claw 210 are symmetrical on the front side and the back side,
In FIG. 8, only the back side is shown. First, the movable end fence 213 for aligning the rear ends of the stored sheet bundle 212 and pushing it out in the sheet re-feeding direction is attached to the intermediate tray 200a.
It is provided so as to be movable back and forth along a groove 200b provided on the bottom surface (a driving means such as a motor is not shown). Also,
The movable bottom plate 211 is provided on the intermediate tray 200a so as to be slidable forward and backward in the re-feeding direction.
It is rotatably provided at the tip of 5. At this time,
As shown in FIG. 3 and FIG.
By providing 1b and making it penetrate under the bottom plate arm 215 to support it, the movable direction of the movable bottom plate 211 is restricted only to the upward direction. Thereby, the movable bottom plate 21
It is possible to move 1 while always keeping it horizontal, and it is possible to improve reliability during transfer.

The separating claw 210 is rotatably supported by the tip of a claw arm 214 which is slidable in the refeedable direction (slides along the groove 205a) with respect to the movable side fence 205. There is. Then, the separation claw 210
Is through the lower side of the movable bottom plate 211 and the tip is movable.
The movable bottom plate 211 is provided so as to be hung on 11
The separation claw 210 can also be moved in the sheet re-feeding direction in association with the movement of the sheet.

Further, the movable side fence 205 can be moved laterally along the groove 200c by a driving means such as a motor, and the separating claw 210 is moved laterally in association with the movement of the movable side fence 205. You can move in any direction. As a result, it becomes possible to align the stored sheet bundle 212 in the lateral direction and cope with sheets of different sizes.

Further, the projecting bottom portion 211a provided below the movable bottom plate 211 is provided so as to be located inside the separating claw 210 as shown in the drawing, and is smaller than the width of the minimum size paper on the paper feed tray 100 side. By doing so, it is possible to prevent the separation claw 210 of the duplex unit 200 from interfering with the separation claw 110 on the side of the sheet feeding tray 100 located below (double-sided re-feeding as shown in FIGS. 4 and 7). It becomes a problem in the paper state). In addition, the movable bottom plate 21 as shown in FIG.
Even in the retracted state of 1, the separation claw 210 can be moved in the lateral direction (at the time of alignment). Also, the claw arm 214
Since the sheet moves in the sheet re-feeding direction together with the movable bottom plate 211 and the separation claw 210 during double-sided sheet re-feeding (FIG. 7), the claw arms 214 are provided inside the movable side fence 205 to remove both side edges of the sheet. It is possible to guide and it is possible to prevent the skew that occurs at the time of re-feeding.

FIG. 9 is a perspective view for explaining the movement of the guide member, and FIG. 10 is a side view of the same. As shown in the figure, a guide member 209 composed of mylar or the like is provided on the upper guide 205b provided on the movable side fence 205. By providing the guide member 209 with an angle θ in advance (see FIG. 10), when the movable bottom plate 211 returns to the home position (states in FIGS. 9 and 10), the separation claw 210 is released.
It prevents interference with.

Further, at the time of transfer, at the same time that the front end of the sheet bundle 212 enters the front end portion 210a of the separation claw 210, the sheet bundle 212 ascends and retracts along the upper surface of the sheet bundle 212 in the E direction (see FIG. 10). As a result, the front end of the sheet bundle 212 is separated from the separation claw 2.
It is possible to reliably lead to 10.

Further, as shown in FIGS. 13 and 14, the claw arm 214 is provided with a projecting locking means 214a for restricting the rotatable direction of the separation claw 210 only in the upward direction.
The gap δ is maintained between the separation claw tip 210a and the movable bottom plate 211 at all times to facilitate the insertion of the tip of the sheet bundle 212 into the separation claw tip 210a (see FIG. 14). At the time of paper feeding, the separation claw 210 is rotatable only in the upward direction, so that when the movable bottom plate 211 rises, the separation claw tip portion 210a hangs on the tip of the sheet bundle 212 by its own weight, and becomes separable. In FIG. 13, an upward arrow ◯ indicates that the arrow can be rotated in this direction, and a downward arrow x indicates that the arrow cannot be rotated in this direction.

FIG. 11 is an overall plan view showing the drive mechanism for the movable end fence and the movable bottom plate, and FIG. 12 is an enlarged plan view of the relevant parts. The movable end fence 213 is provided with a rack portion 213a, and the bottom plate arm 215 is provided with a rack portion 215a. Further, home position detecting means 217 is provided behind the movable end fence 213. Further, a fixed gear 218 connected to the drive motor 216, an idler gear 219 rotatable while abutting on the outer periphery of the fixed gear 218, and an idler gear 219 are provided between the racks.
Is provided with a connection switching means composed of a solenoid 220 for performing the above-mentioned movement, a spring 221 and the like.

With the above configuration, when the solenoid 220 is off, the idler gear 219 is in the retracted state by the spring 221, and in this state, the rack portion 215a of the bottom plate arm 215 is not driven and only the movable end fence 213 is moved. Driven. Also, the solenoid 2
When the gear 20 is on, the idler gear 219 moves to the fixed gear 2
It rotates along the outer circumference of 18, contacts the rack portion 215a of the bottom plate arm 215, and the drive is connected.

In this state, the movable end fence 21
3 and the bottom plate arm 215 are driven in the same direction. Therefore,
With these configurations, the movement of the movable end fence 213 and the movement of the movable bottom plate 211 can be performed by one drive unit, and the drive connection can be freely switched at any position (timing).

In the above-described embodiment having the above-mentioned configuration, the paper feed tray 100 for storing the paper, the feeding means 2 for feeding the paper, and the movable bottom plate 105.
Place a separation claw 110 abuts against the opposite edges of the sheet leading edge of the upper to the paper feed tray 100 forward, separating convey the sheet one by one minute
An intermediate tray 20 for accommodating a sheet having an image formed on one surface thereof in the space above the paper feed tray 100 and behind the feeding means 2 and the separating means (a pair of separating claws 110).
0a and, once supported the front end of the accommodated sheet bundle, and the duplex paper feed apparatus having a duplex unit 200 formed of forward and backward a movable bottom plate 211 in the sheet re-feeding direction,
The provided separation claw 2 10 the movable bottom plate 211, an intermediate tray 20
0a, and the bundle of sheets supported by the movable bottom plate 211 is collectively transferred to the refeed position, and then the feeding means 2 is also used to refeed the sheet to the image forming unit. The reliability of can be improved. Also,
A simple and inexpensive feeding means (half-moon roller) that does not use a pick-up means, a retracting means, or the like makes it possible to re-feed paper from both sides, and it is possible to provide a very inexpensive double-sided paper feeding device.

Further, in the above-described embodiment, the movable bottom plate 211 is configured to be retracted upward during the sheet feeding operation from the sheet feeding tray 100 located below, so that the movable bottom plate included in the duplex unit 200 is provided. The space efficiency of the duplex unit 200 is improved by retracting the sheet feeding device 211 upward when the sheet is fed from the lower sheet feeding tray 100.

In the above embodiment, the movable side fence 205 having the double-sided unit 200 is provided with the separating claw 110 which is movable back and forth in the re-feeding direction. Separation claw 1 for moving in the direction
10 can work together to handle various sizes of paper.

Further, in the above-described embodiment, the movable end fence 213 for aligning the rear end of the sheet bundle stored in the intermediate tray 200a and pushing the leading edge of the sheet bundle to the position where the sheet can be re-fed. Since the movement of the movable bottom plate 211 is connected to the movement of the movable end fence 213, the movable end fence 213 having the double-sided unit 200 pushes out the rear end of the sheet bundle when transferring the sheet bundle, and improves the reliability of the transfer. By connecting and disconnecting the drive of the end fence 213 and the drive of the movable bottom plate 211, it is possible to freely control both drive states with one drive means and to reduce the cost. .

Further, in the above-described embodiment, the guide for suppressing the floating of the paper is provided above the separation claw 110 provided in the duplex unit 200 and at the position which guides both side edges of the bundle of papers conveyed. Since the member 209 is provided, it is possible to reliably guide and infiltrate the leading end of the conveyed sheet bundle to the leading end 110a of the separation claw 110, and improve the reliability during transportation.

Further, in the above-described embodiment, the first bottom plate 10 for stacking sheets on the side of the sheet feed tray 100.
5 and a second bottom plate 106 that supports the first bottom plate 105 from below via a pressing means 108 such as a spring, and the second bottom plate 106 is moved up and down by the drive means. Can be moved to the paper feedable position and the retracted position (the retracted position is the position when the movable bottom plate 211 of the duplex unit 200 is moved to the refeeding position). Further, by pushing up the movable bottom plate 211 from below during double-sided sheet re-feeding, it is possible to use the pressing force for double-sided sheet re-feeding.

Further, in the above-described embodiment, the projecting bottom portion 211a that receives the pressing force of the pressing mechanism of the bottom plate of the sheet feeding tray 100 is provided below the movable bottom plate 211 provided in the duplex unit 200. Therefore, when the pressing means of the lower paper feed tray 100 also serves as the urging means of the pressing force at the time of double-sided paper re-feeding, the separation claw 110 on the duplex unit 200 side and the separation claw 110 on the paper feed tray 100 side. Interference can be prevented. Moreover, since the pressure is also used, the cost can be reduced.

Further, in the above-described embodiment, the separation claw 110 is provided so that the rotatable direction thereof is restricted only to the upward direction. Therefore, for example, the separation claw 110 provided in the double-sided unit 200 is used as a sheet bundle. A locking member is provided for keeping horizontal during transfer and for restricting the rotatable direction only to the upward direction, so that the tip of the separation claw 110 is always supported to be lifted when the movable bottom plate 211 is not lifted, that is, during the transfer operation. For example, the margin for guiding and infiltrating the tip of the conveyed sheet bundle to the separation claw tip 110a is increased,
It is possible to further improve reliability during transfer.

[0056]

[0057]

Effects of the Invention According to the first aspect of the invention, the movable bottom plate which is provided on both sides unit, by retracting upward during paper feeding from the bottom of the paper feed tray, to improve the space efficiency of the duplex unit be able to.

According to the second aspect of the present invention, the movable side fence provided with the double-sided unit is provided with the separating claw so as to be movable back and forth in the re-feeding direction, so that the side fence can be separated in the lateral movement. The claws are interlocked with each other so that various sizes of paper can be supported.

According to the third aspect of the present invention, the movable end fence equipped with the double-sided unit pushes out the rear end of the sheet bundle when the sheet bundle is transferred, improving the reliability of the transfer and driving the end fence. By connecting and disconnecting the drive of the movable bottom plate, both drive states can be freely controlled by one drive means, and the cost can be reduced.

According to the fourth and sixth aspects of the invention, the leading end of the sheet bundle can be reliably guided to the separation claw by the guide member, and the reliability at the time of transfer can be improved.

[0061]

According to the fifth and seventh aspects of the present invention, it is possible to obtain the sheet feeding pressure on both the sheet feeding tray side and the duplex unit side with one urging means, so that the cost can be reduced. it can. In addition, it is possible to prevent interference between the two separating claws.

According to the invention described in claim 8, the margin at the time of inducing and infiltrating the tip of the conveyed sheet bundle to the tip of the separation claw is increased, and the reliability at the time of conveyance is further improved. You can

[Brief description of drawings]

FIG. 1 is a perspective view of a state where a paper feed tray is pulled out from a main body of an image forming apparatus.

FIG. 2 is a configuration diagram of a double-sided sheet feeding device according to an embodiment of the present invention.

FIG. 3 is a configuration diagram showing a paper feeding state from a paper feeding tray side.

FIG. 4 is a configuration diagram showing a re-feeding state from the duplex unit side.

FIG. 5 is a configuration diagram for explaining a first stage operation of transferring a sheet bundle stored in an intermediate tray to a refeed position.

FIG. 6 is a configuration diagram for explaining an operation of the second stage.

FIG. 7 is a configuration diagram for explaining a re-feeding operation from the duplex unit.

FIG. 8 is a perspective view of a main part of the duplex unit.

FIG. 9 is a perspective view for explaining the function of a guide member.

FIG. 10 is a side view of the same.

FIG. 11 is an overall plan view showing a drive mechanism for a movable end fence and a movable bottom plate.

FIG. 12 is an enlarged plan view of an essential part of the same.

FIG. 13 is a configuration diagram showing a state of a movable bottom plate during transfer standby.

FIG. 14 is a configuration diagram showing a state of a movable bottom plate at the time of re-feeding.

[Explanation of symbols]

2 Paper feeding means 100 paper tray 105 First bottom plate 106 Second bottom plate 107 Lifting arm 108 Pressure spring 110 separate nails 110a Separation claw tip 200 duplex unit 200a Intermediate tray 205 movable side fence 210 Separated nail 211 Movable bottom plate 211a protruding bottom 213 Movable end fence

Claims (8)

(57) [Claims] 1. A sheet feeding tray for receiving the sheets, disposed and feeding means for feeding the paper, the separation claw abutting the edges of the sheet leading edge on the movable bottom plate in the paper feed tray forward, the The movable bottom fed by the feeding means
Separation means for separating and transporting the sheets on the plate one by one, and an intermediate tray for accommodating the sheet with an image formed on one side in the space above the paper feed tray and behind the feeding means. temporarily supporting the leading end of the accommodated sheet bundle, and e Bei a duplex unit constituted by the forward-reverse moveable bottom plate refeed direction, the separating claw in the movable bottom plate is provided, in the intermediate tray A double-sided sheet feeding device in which a bundle of sheets stored and supported by the movable bottom plate is collectively transported to a sheet re-feeding position, and then the sheet is also fed again to the image forming unit by using the feeding means.
In addition, during the paper feeding operation from the paper feeding tray located below,
A double-sided sheet feeding device, wherein the movable bottom plate is configured to be retracted upward . 2. A paper feed tray for storing paper,
Feeding means for feeding the paper and paper on the movable bottom plate
The separation claws that come into contact with both edges of the tip are placed in front of the paper feed tray.
The movable bottom that is placed and sent by the feeding means.
Separation means for separating and transporting the sheets on the plate one by one, and
Space above the paper tray and behind the feeding means
Inside for storing paper with an image formed on one side
Support the tray and the leading edge of the stack of paper once stored.
Consists of a movable bottom plate that can move forward and backward in the refeed direction
A double-sided unit is provided, and the movable bottom plate is provided with separation claws and is stored in the intermediate tray.
And bundle of sheets supported by the movable bottom plate
Then, after transferring to the refeed position, the feeding means is also used.
Double-sided paper feeder that feeds paper to the image forming section again
A double-sided paper feed characterized in that a movable side fence for aligning both side edges of the paper is provided, and the separation claw is provided so as to be movable forward and backward in the re-feeding direction with respect to the movable side fence. apparatus. 3. A paper feed tray for storing paper,
Feeding means for feeding the paper and paper on the movable bottom plate
The separation claws that come into contact with both edges of the tip are placed in front of the paper feed tray.
The movable bottom that is placed and sent by the feeding means.
Separation means for separating and transporting the sheets on the plate one by one, and
Space above the paper tray and behind the feeding means
Inside for storing paper with an image formed on one side
Support the tray and the leading edge of the stack of paper once stored.
Consists of a movable bottom plate that can move forward and backward in the refeed direction
A double-sided unit is provided, and the movable bottom plate is provided with separation claws and is stored in the intermediate tray.
And bundle of sheets supported by the movable bottom plate
Then, after transferring to the refeed position, the feeding means is also used.
Double-sided paper feeder that feeds paper to the image forming section again
A is said to match the rear end of the accommodated sheet bundle on the intermediate tray and provided with a movable end fence for extruding sheet bundle tip to refeed possible positions, the movable movement of the movable bottom plate Double-sided paper feeder characterized in that it is connected to and driven by a movable type end fence. 4. A paper feed tray for storing paper, and
Feeding means for feeding the paper and paper on the movable bottom plate
The separation claws that come into contact with both edges of the tip are placed in front of the paper feed tray.
The movable bottom that is placed and sent by the feeding means.
Separation means for separating and transporting the sheets on the plate one by one, and
Space above the paper tray and behind the feeding means
Inside for storing paper with an image formed on one side
Support the tray and the leading edge of the stack of paper once stored.
Consists of a movable bottom plate that can move forward and backward in the refeed direction
A double-sided unit is provided, and the movable bottom plate is provided with separation claws and is stored in the intermediate tray.
And bundle of sheets supported by the movable bottom plate
Then, after transferring to the refeed position, the feeding means is also used.
Double-sided paper feeder that feeds paper to the image forming section again
A guide member for guiding both side edges of the sheet and guiding both ends of the leading edge of the sheet to the separating claw and sneaking into the separating claw when the sheet bundle is transported to a position where it can be re-fed. A double-sided paper feeder characterized in that 5. A paper feed tray for storing paper, and
Feeding means for feeding the paper and paper on the movable bottom plate
The separation claws that come into contact with both edges of the tip are placed in front of the paper feed tray.
The movable bottom that is placed and sent by the feeding means.
Separation means for separating and transporting the sheets on the plate one by one, and
Space above the paper tray and behind the feeding means
Inside for storing paper with an image formed on one side
And between tray, temporarily support the leading edge of the accommodated sheet bundle, or
Consists of a movable bottom plate that can move forward and backward in the refeed direction
A double-sided unit is provided, and the movable bottom plate is provided with separation claws and is stored in the intermediate tray.
And bundle of sheets supported by the movable bottom plate
Then, after transferring to the refeed position, the feeding means is also used.
Double-sided paper feeder that feeds paper to the image forming section again
The bottom of the movable bottom plate is provided with a projection shape, and the biasing force of the pressing force to the movable bottom plate at the time of re-feeding is controlled by the pressurizing mechanism of the bottom plate of the sheet feeding tray located below. A double-sided sheet feeding device characterized by being used for both purposes. 6. The double-sided sheet feeding device according to claim 2,
When transferring the stack of paper to a position where
Guides the edge and guides both edges of the paper to the separation claw
A double-sided sheet feeding device comprising a guide member for sneaking into the separating claw . 7. A paper feed tray for storing paper, and
Feeding means for feeding the paper and paper on the movable bottom plate
The separation claws that come into contact with both edges of the tip are placed in front of the paper feed tray.
The movable bottom that is placed and sent by the feeding means.
Separation means for separating and transporting the sheets on the plate one by one, and
Space above the paper tray and behind the feeding means
Inside for storing paper with an image formed on one side
Support the tray and the leading edge of the stack of paper once stored.
Consists of a movable bottom plate that can move forward and backward in the refeed direction
A double-sided unit is provided, and the movable bottom plate is provided with separation claws and is stored in the intermediate tray.
And bundle of sheets supported by the movable bottom plate
Then, after transferring to the refeed position, the feeding means is also used.
Double-sided paper feeder that feeds paper to the image forming section again
And a first bottom plate that supports the paper on the side of the paper feed tray,
And a second bottom plate below the
It is common to hold a spring means for urging pressure.
Then, by raising and lowering the second bottom plate,
When the paper is re-fed, the bottom of the movable bottom plate is provided with protrusions so that the paper can be moved to and retracted from the paper-possible position.
Of the pressing force to the movable bottom plate of the
Use the pressure mechanism of the bottom plate of the paper feed tray
Duplex paper feeding apparatus being characterized in that the. 8. The double-sided sheet feeding device according to claim 2 ,
The double-sided sheet feeding device, wherein the separating claw is provided so that the rotatable direction thereof is restricted only to the upward direction.