JP3410858B2 - 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 sheet feeding device in an image forming apparatus such as a copying machine, a facsimile and a printer.

[0002]

2. Description of the Related Art Conventionally, as a sheet feeding device in an image forming apparatus such as a copying machine, a sheet feeding cassette for stacking and accommodating sheets is arranged at the bottom of an image forming apparatus main body, and the sheet feeding cassette is used for conveying sheets. A front loading type sheet feeding device configured to be pulled out in a direction orthogonal to the direction is known. Further, two paper accommodating portions are provided in a paper feed cassette for small-sized paper in this kind of paper feeding device, and when the sheets stacked in the first paper accommodating portion are exhausted, the second paper accommodating portion is provided. JP-A-3-22303 is configured so that the stacked sheets are transferred to the first sheet accommodating portion and the surplus space of the sheet feeding cassette is effectively used.
No. 1 publication, "Paper feeder", JP-A-4-28634, "Paper feeder", JP-A-4-28635, "Paper feeder", JP-A-4-179634. "Paper feeder", "Paper feeder" described in Japanese Patent Laid-Open No. 4-101934, "Mass paper feeder" described in Japanese Patent Laid-Open No. 5-221536 and the like are known. Incidentally, as a technique for transferring a spare sheet stacked behind the sheet to the sheet feeding section when the sheets stacked on the sheet feeding section are exhausted, there is a technique described in JP-A-49-33638. "Replenishing device" has been proposed.

[0003]

By the way, the above-mentioned "paper feeder" described in JP-A-3-223031, the "paper feeder" described in JP-A-4-28634, and
In the "paper feeder" described in JP-A-4-28635,
The back fence that positions the trailing edge of the paper in the first paper storage unit tilts forward as the paper stack in the second paper storage unit (auxiliary tray) is transferred, thereby ensuring a paper transfer zone. However, in this configuration, since the back fence of the first paper storage unit remains tilted after the paper of the second paper storage unit is transferred to the first paper storage unit, the back fence for paper transfer is It is necessary to stop in place and position the paper. As described above, in these paper feeding devices, when the paper in the second paper storage unit is transferred to the first paper storage unit, the back fence for paper transfer does not return to the home position. Even if an attempt is made to replenish the second sheet accommodating portion, which is an empty space due to the transfer, with the sheet, the replenishment cannot be performed. Therefore, in these paper feeding devices, the paper can be supplied to the second paper storage unit only when all the papers in both the first and second paper storage units are consumed (paper feed), When the apparatus is not used, it is impossible to replenish the spare sheet at any time, and the operability and the productivity are deteriorated.

Further, in these sheet feeding devices, the back fence of the first sheet accommodating section is configured to be retracted by being pressed by the tip of the sheet bundle stacked in the second sheet accommodating section. Therefore, in these paper feeding devices, when the number of sheets of paper stacked in the second paper storage unit is small, the leading end of the paper may buckle under the load of the back fence of the first paper storage unit. There is this, and usability is poor.

On the other hand, the above-mentioned conventional Japanese Patent Laid-Open No. 4-179.
"Paper feeding device" described in Japanese Patent Laid-Open No. 634, JP-A-4-1019
"Paper feeder" described in Japanese Patent Laid-Open No. 34-34, and JP-A-5-22
In the "mass paper feeder" described in Japanese Patent No. 1536, the back fence for transferring the paper returns to the home position in a state where the paper in the second paper storage unit is transferred to the first paper storage unit, so Paper can be replenished at any time to the second paper storage unit, which is an empty space by the transfer, and its operability and productivity are improved. Further, in these paper feeding devices, since the back fence of the first sheet storage section is configured to be retracted from the sheet transfer zone by an actuator such as a solenoid or a motor, it is loaded in the second sheet storage section. Even when the number of stacked sheets is small, the above-mentioned buckling of the leading end of the sheet does not occur, and the usability thereof can be improved. However, in these sheet feeding devices, an electrically operated actuator is used as a means for retracting the back fence of the first sheet accommodating section from the sheet transfer zone, so that the configuration becomes complicated and the cost increases. There is a problem that becomes.

The present invention has been made in view of the above points, and an object of the present invention is to provide a sheet in a second sheet container to a first sheet.
Immediately after being transferred to the paper storage unit, the second paper storage unit can be replenished with paper at any time, and the drive source of the back fence of the first paper storage unit can also be used as the drive source of the paper transfer unit. An object of the present invention is to provide a sheet feeding device that can improve the cost and reduce the cost.

Another object of the present invention is to provide a paper feeding device which can more securely regulate the back fence for regulating the rear end of the sheet bundle of the first sheet accommodating portion and prevent the sheet from being obliquely fed or jammed. To provide.

[0008]

In order to solve the above-mentioned problems, the present invention provides, in claim 1, a first container accommodating portion for stacking a plurality of sheets of paper, and a sheet from the first container accommodating portion. A sheet feeding device that feeds the sheets one by one, a second sheet accommodating section that is arranged substantially horizontally and in parallel with the first sheet accommodating section, and a rear end of the sheets stacked in the second sheet accommodating section are provided. In a sheet feeding device having a sheet transfer means for pressing and transferring a sheet to the first sheet storage section, a sheet transfer means driving section including a forward / reverse rotation motor for reciprocating the sheet transfer means in the sheet transfer direction. And a back fence for positioning the trailing edge of the sheets stacked in the first sheet storage section, and a driving force transmitted from the sheet transfer means driving section via a torque limiter to retract the back fence from the sheet transfer area. Back fence evacuation means for A configuration that includes.

According to a second aspect of the present invention, the torque limiter has a characteristic that the torque value increases as the drive speed of the transfer means drive unit increases.

According to a third aspect of the present invention, the torque limiter has a structure in which a fin provided on the drive shaft of the transfer means drive unit is hermetically sealed in an oil enclosure provided on the support side of the drive shaft.

[0011]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a schematic view of a known electrophotographic copying machine. An image forming apparatus 101 is installed on the upper portion of the copying machine body, and a paper feeding apparatus 102 embodying the present invention is provided on the lower portion. is set up.

The sheet feeding device 102 of this copying machine is provided with upper and lower two sheet feeding portions, and the lower sheet feeding portion has A3 and B4.
A conventional paper feed tray 301 for accommodating and storing large-sized sheets of paper such as
A paper feed tray 302 embodying the present invention for accommodating and storing small-sized paper such as 5 is installed.

The paper feed tray 302 in this embodiment includes a first paper storage unit 1 (on the right in FIG. 1) for stacking and storing paper P1 used for image formation, and a second paper for stacking and storing spare paper P2. It has a storage section 2 (on the left side in FIG. 1), and these sheet storage sections 1 and 2 are 500 sheets each of small-sized sheets P1 and P2 such as A4 and B5 in the lateral direction. Each of them (1000 sheets in total) can be stored.

At the front edge of the first sheet storage section 1 on the sheet transport side (right side in FIG. 1), the sheets P1 stacked in the first sheet storage section 1 are separated one by one. Image forming apparatus 10
A sheet feeding unit 4 is provided for feeding the sheet to one image forming unit. As the sheet feeding means 4, a well-known roller separation method, suction separation method or the like can be adopted, and in the present embodiment, the former method is adopted. Specifically, the bottom plate 401 on which the sheets P1 are stacked is pushed up by the lever 402 to bring the topmost sheet of the sheet bundle into contact with the pickup roller 403,
By rotating the pickup roller 403 in this state, the uppermost sheet is fed to the paper feed roller 404 and the separation roller 40.
The sheet is fed to the nip portion with the sheet feeding device 5, and the sheets are separated one by one by the nip portion and sent to the image forming portion of the image forming apparatus 101.

Further, between the pickup roller 403 of the sheet feeding means 4 and the sheet feeding roller, the sheet P1 stacked in the first sheet accommodating portion 1 is consumed, and it is detected that the sheet P1 is gone. The paper end sensor 5 is provided. When the paper end sensor 5 detects that the sheets P1 stacked in the first sheet storage unit 1 are exhausted, the spare sheets P2 stacked in the second sheet storage unit 2 are detected.
The pressing plate 6 of the sheet transfer means (described later in detail) located at the home position of the rear end portion (left side in FIG. 1) of
While pushing the trailing edge of the spare sheet P2, it moves forward to the trailing edge position of the sheet P1 (the position shown by the chain line in FIG. 1),
2 is moved to the paper feed position of the first paper storage unit 1. As a result, the paper end sensor 5 is restored and the paper feeding operation by the paper feeding means 4 can be continued, and the pressing plate 6 moves back to the home position of the spare paper stacking position of the second paper accommodating portion 2. Then, it becomes possible to replenish the second sheet accommodating portion 2 with new spare sheet P2 at any time.

The second of the paper feed tray 302 in this embodiment
As shown in FIG. 2, a rib 302a for stacking the spare sheets P2 and a pair of side fences 21 for restricting the lateral side positions of the spare sheets P2 (the front side is (Not shown) and a pressing plate 6 that regulates the rear end position of the spare sheet P2 in the transport direction are provided.

The pressing plate 6 is connected to a slider 7 arranged below the pressing plate 6 with a screw via a boss portion 7a of the slider 7. The pressing plate 6 is used for the paper feed tray 30.
The second boss portion 7 of the slider 7 is provided in the elongated guide hole 302b provided in the bottom portion of the second sheet storage portion 2 parallel to the sheet transfer direction.
When a is fitted, it can be moved linearly, and a fork-shaped locking piece 7b formed in the lower part of the slider 7 is used to sandwich the timing belt 8 of the paper transporting means drive section. , Is moved in association with the rotation of the timing belt 8.

The timing belt 8 is stretched by timing pulleys 9 and 10 and a gear pulley 11 so as to be rotatable in forward and reverse directions. The gear pulley 11 meshes with the forward / reverse rotation motor 12, and the forward / reverse rotation of the forward / reverse rotation motor 12 causes the timing belt 8 to be forward / reversely rotated via the gear pulley 11.
The pressing plate 6 together with the slider 7 locked to the long hole 30
It is reciprocally moved in the paper transfer direction along 2b. At this time, the reciprocating range of the pressing plate 6 is such that the detected pieces 7c provided on the front surface and the rear surface of the slider 7 in the paper transfer direction are the paper transfer completion position sensor S1 arranged on the lower surface of the paper feed tray 302. Further, when it is detected by the home position sensor S2, it is determined by performing reverse control and stop control of the rotation direction of the forward / reverse rotation motor 12.

On the other hand, at the bottom of the first sheet accommodating section 1, the above-mentioned bottom plate 401 of the sheet feeding means 4 and a pair for regulating the lateral position of the sheets P1 stacked in the first sheet accommodating section 1 in the width direction. The side fence 14 and the pair of back fences 15 for restricting the rear end position of the sheet P1 in the sheet feeding direction are provided.

Each back fence 15 is pivotally supported on the outer side of each side fence 14 by a support shaft 13 so that the back fence 15 is supported by elastic force of a torsion coil spring 18 wound around the support shaft 13. , Is biased to face the trailing edge regulation position of the paper. Here, as shown in FIG. 2, in a state in which the sheets P1 are not stacked in the first sheet storage unit 1, each back fence 15 exceeds the sheet trailing edge regulation position and enters the sheet P1 stacking area. It is set so as to face a slightly biting position, and in this state, the swing of each back fence 15 due to the elasticity of the torsion coil spring 18,
The abdomen of each back fence 15 and the rear edge 14a of each side fence 14 are set to be blocked. As a result, in a state where the sheets P1 are stacked in the first sheet storage unit 1, each back fence 15 elastically abuts the rear edge of the sheet P1 by the elastic force of the torsion coil spring 18, so that the sheets P1 The position of the rear end can be regulated more reliably.

Also, at the bottom of each back fence 15,
Each swing lever 15a (the rear side is not shown) is integrally formed via the support shaft 13. These rocking levers 15a are arranged at the lower part of the bottom plate 401 by fitting the pins 16a planted at the extended ends of the rack gears 16 into the elongated holes 15b formed at the extended ends thereof. The rack gears 16 are engaged with each other. Further, each rack gear 16 meshes with one pinion gear 17, respectively. The pinion gear 17 is configured to rotate integrally with the timing pulley 9 via a torque limiter 20 which will be described later, and the forward movement of the timing belt 8 causes the timing pulley 9 and the torque limiter 20 to move.
By rotating the pinion gear 17 in the counterclockwise direction in FIG. 2, the respective extension ends are respectively moved inward in the direction orthogonal to the sheet feeding direction. The movement of the pinion gear 17 at this time is such that one of the inner ends of the stopper 30 is a stopper 30 that is planted at the bottom of the paper feed tray 302.
It is stopped when it comes into contact with 2c. As a result, the back fences 15 are swung through the swing levers 15a fitted to the rack gears 16 and retracted from the sheet bundle transfer zone. The spare sheet P2 can be transferred to the first sheet container 1.

As shown in FIG. 3, the timing pulley 9 and the pinion gear 17 are rotatably supported by penetrating the short shaft 19, and the timing pulley 9 and the short shaft 19 are mutually supported by a spring pin (not shown). It is connected. Further, the pinion gear 17 has a built-in torque limiter 20. The torque limiter 20 in this embodiment encloses oil in a hollow casing 20a formed in the pinion gear 17, and the fin 20b fixed to the short shaft 19 rotates in the casing 20a filled with the oil. Accordingly, the oil type torque limiter that generates the rotation torque of the pinion gear 17 is configured.

With this configuration, the torque limiter 20 absorbs an excessive amount of rotation of the forward / reverse rotation motor 12 with respect to the pinion gear 17 when the pressing plate 6 moves, and the back fence 15 has different drive strokes. It is possible to drive both the rocking of and the reciprocating movement of the pressing plate 6 by one drive source (here, the forward / reverse rotation motor 12). That is, each back fence 1
As shown in FIG. 2, the pressing plate 6 has a spare sheet P2.
When moving forward in the direction of pushing the sheet into the first sheet accommodating portion 1, an urging force acts in the direction of retracting from the sheet bundle transfer zone, and when the pressing plate 6 moves back toward the home position, the sheet bundle is returned. A biasing force acts in the direction of entering the transfer zone. However, the swing range of the back fence 15 is, as described above, the contact between the abdomen of each back fence 15 and the rear edge 14a of each side fence 14, and the inner end of the pinion gear 17 and the stopper 302c. It is regulated by the contact. Therefore, normally,
It is virtually impossible to drive both the swing of the back fence 15 and the reciprocating movement of the pressing plate 6 by one drive source (here, the forward / reverse rotation motor 12) because the drive strokes are different from each other. . Therefore, in the present embodiment, as described above, the forward / reverse rotation motor 1 when the pressing plate 6 moves.
The torque limiter 20 absorbs an excessive amount of rotation of the pinion gear 17 from 2. As a result, it becomes possible to perform dual-purpose driving of members of two systems having mutually different driving strokes, which is normally impossible, by one driving source.

FIG. 4 shows the relationship between the torque value and the drive speed of the oil type torque limiter in this embodiment. The torque limiter 20 in the present embodiment, as shown in FIG.
As the driving speed V becomes higher, the torque value Tr becomes
Also grows. In FIG. 4, the drive speed Va indicates the drive speed in this embodiment, and the torque value Tra indicates the torque value at the drive speed Va. Further, the torque value Trb is a torque value generated by the above-mentioned torsion coil spring 18 for returning the back fence 15 to the sheet bundle transfer zone.

Here, the torque value T at the driving speed Va
If the relation between ra and the torque value Trb for returning the back fence 15 to the sheet bundle transfer zone is set so that Tra> Trb, the back fence 15 is driven by the forward / reverse rotation motor 12. Even if does not act, the torque value Trb generated from the torsion coil spring 18
It is naturally returned to the sheet bundle transfer zone. Therefore, according to the present embodiment, even if the user mistakenly moves the back fence 15 from the paper trailing edge regulating position when the paper P1 or the spare paper P2 is replenished, the above-mentioned torsion coil spring 18 generates it. The back fence 15 can be automatically returned to the sheet trailing edge regulation position by the torque value Trb.

As described above, by using the torque limiter in which the torque value is displaced according to the driving speed, it is possible to back up the erroneous operation by the user. When using the limiter, the user himself / herself checks the position of the back fence 15, and if the back fence 15 is out of the predetermined position, the user himself / herself should reset the back fence 15 to the predetermined position. You may teach.

[0027]

As described above, according to the present invention, in claim 1, since the back fence can be previously retracted from the sheet bundle transfer zone when the sheet bundle is transferred, the sheet being transferred by the back fence is conveyed. Good paper transfer and paper feed can be realized without buckling the bundle. Further, since the sheet transfer means returns the home position of the spare sheet after transferring the spare sheet to the first sheet storage section, it is possible to replenish the second sheet storage section with the spare sheet at any time and operate the sheet feeding device. Productivity and productivity are improved. Furthermore, the paper transport means and the back fence, which have different drive strokes,
By driving through the torque limiter, the single drive source can be used for dual use, so that the paper feeding device can be simplified and the cost can be reduced.

In the second aspect, the back fence is driven via the torque limiter having the characteristic that the torque value increases according to the driving speed, so that the back fence is driven even when the driving motor (forward / reverse rotation motor) is not driven. The fence can be moved to the paper edge regulation position, and paper skew and jam can be prevented in advance.

According to the third aspect, the torque limiter for obtaining the predetermined torque can be obtained with a simple structure, so that the cost of the sheet feeding device can be further reduced.

[Brief description of drawings]

FIG. 1 is a schematic view of a copying machine using an embodiment of a paper feeding device according to the present invention.

FIG. 2 is a schematic perspective view of a paper feeding tray in the embodiment of the paper feeding device according to the present invention.

FIG. 3 is a partially enlarged perspective view of a sheet transfer unit driving section in the embodiment of the sheet feeding device according to the present invention.

FIG. 4 is a graph showing a relationship between a torque value of an oil type torque limiter and a driving speed in an embodiment of a paper feeding device according to the present invention.

[Explanation of symbols]

1 First paper storage 2 Second paper storage 4 Paper feeding means 5 Paper end sensor 6 Press plate 7 slider 7a Boss 7b Locking piece 7c Detected piece 8 Timing belt 9,10 Timing pulley 11 gear pulley 12 Forward / reverse motor 13 spindles 14 Side fence 15 back fence 15a Swing lever 15b long hole 16 rack gears 16a pin 17 pinion gear 18 torsion coil spring 19 End shaft 20 Torque limiter 20a casing 20b fin 302 paper feed tray 302a rib 302b guide long hole 302c stopper P1 paper P2 spare paper S1 Paper transfer completion position sensor S2 Home position sensor

Continuation of front page (56) Reference JP-A-4-179634 (JP, A) JP-A-7-76428 (JP, A) JP-A-6-144600 (JP, A) JP-A-6-161166 (JP , A) JP 6-107349 (JP, A) JP 5-221536 (JP, A) JP 4-101934 (JP, A) JP 4-28635 (JP, A) JP 4-28634 (JP, A) JP-A-3-223031 (JP, A) JP-A-49-33638 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B65H 1/30 320 B65H 1/04 326 G03G 15/00 516

Claims (3)

(57) [Claims] 1. A first container accommodating portion for stacking a plurality of sheets of paper, a sheet feeding device for feeding the sheets one by one from the first container accommodating portion, and a substantially horizontal position with respect to the first sheet accommodating portion. A paper feed including a second paper storage unit arranged in parallel and a paper transfer unit that presses a rear end of the paper stacked in the second paper storage unit to transfer the paper to the first paper storage unit. In the apparatus, a paper transport means driving unit including a forward / reverse rotation motor for reciprocating the paper transport means in the paper transport direction, and a back fence for positioning the trailing edge of the paper stacked in the first paper storage unit. And a back fence retracting unit for retracting the back fence from the sheet transporting area by transmitting a driving force from the sheet transporting unit driving unit via a torque limiter. 2. The paper feeding apparatus according to claim 1, wherein the torque limiter has a characteristic that the torque value increases as the driving speed of the transfer means driving unit increases. 3. The torque limiter is characterized in that a fin provided on a drive shaft of the transfer means drive unit is hermetically sealed in an oil-filled container provided on a support side of the drive shaft. The paper feeding device according to claim 2.