JP2001099196A - Drive transmitting mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify a constitution of a drive transmitting mechanism, in a device taking out a sheet from a tray to perform handling action. SOLUTION: In a drive shaft 31 of a separate roller 7 for separating one by one a sheet fed out from a tray, a separate hub 40 is provided movably in an axial direction, by action rotating the drive shaft in a paper feed direction, a drive pawl member 43 of the separate hub is locked to an engaging pawl 34 of the roller 7, to transmit driving. Rotation of the separate hub 40 is drive transmitted to a pickup roller 4 through a clutch pulley 35, drive transmitting and action feeding out the sheet are performed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving mechanism of a paper feeder used to feed out sheets such as originals and recording paper stacked on a tray one by one from above, and more particularly, to driving a separate roller. The present invention relates to a mechanism that can simplify a mechanism for transmitting a drive and transmitting a drive to a pickup roller.

[0002]

2. Description of the Related Art In a sheet feeding device used in an image forming apparatus or the like, sheets are taken out one by one from the sheets stacked and accommodated in a tray, and are multi-fed by a sheet separating device including a separate roller and a retard roller. Then, the sheet is conveyed in the sheet conveying path and sent to the recording unit and the reading unit. When the paper feeding device is used as a document feeder of an image reading device, a transport roller device that takes out documents loaded on a document tray by a pickup roller, separates the documents via a sheet separating device, and arranges the documents on a document transport path. To the reading unit. Then, after reading the original, the original is sent out to the discharge tray.

A pickup roller provided in a paper feeding device such as the above-mentioned document conveying device performs an operation of feeding a sheet such as a document toward a sheet separating device, and the document is conveyed on the downstream side of the sheet separating device. When the roller reaches the roller device, the transport speed of the transport roller device is set to be higher than the transport speed of the separating device and the pickup roller. , One-way clutch).

A one-way clutch mechanism using a coil spring is often provided in order to drive the pickup roller by transmitting the rotation of a separate roller of the sheet separating apparatus. When the pickup roller is driven, the coil spring is wound so as to be tightened and the rotation of the drive shaft is transmitted to the roller. Further, when the sheet is being conveyed by the conveying roller device, the coil spring is loosened to interrupt the drive transmission.

[0005]

However, the coil spring used in the one-way clutch mechanism is configured to be brought into contact with the drive shaft and the driven portion by a slight reduction in diameter. Very strict precision is required for dimensions and the like. Therefore, the coil spring mechanism used for the clutch is expensive, and accuracy is required even during assembly. In order to maintain a state in which the clutch is operated by a small change in force, maintenance of the device and the like are also required. There is also a problem that it becomes troublesome.

An object of the present invention is to provide a drive transmission mechanism having a one-way clutch mechanism which can be simplified in construction, is easy to assemble, and is inexpensive.

[0007]

SUMMARY OF THE INVENTION The present invention relates to a drive transmission mechanism for a paper feeder or the like. The first aspect of the present invention relates to a drive transmission mechanism in which a roller is rotatably supported with respect to a drive shaft. When the roller is slid along the drive shaft with the rotation of the roller and is cam-coupled to the roller, the drive is transmitted to the roller, and a rotational force relatively opposite to the normal rotation acts on the drive shaft. Is characterized in that it has a separate hub that slides in a direction opposite to that during the forward rotation to release the cam connection. Therefore, the structure is simple, and strictness is not required for the manufacturing accuracy and the mounting accuracy, and the assembling work of the device can be easily performed.

According to a second aspect of the present invention, the separate hub is provided with a helical groove, and a pin provided on the drive shaft is housed in the groove, so that the separate hub can be controlled in a restricted range of the groove. Characterized by being slidable along. Therefore, a simplified one-way clutch mechanism can be obtained. According to a third aspect of the present invention, a pickup roller is rotatably supported on the drive shaft via a swingable arm, and is engaged with the separate hub by sliding movement along the axial direction of the hub. And a clutch pulley for releasing the clutch pulley is fitted, and the rotation of the drive shaft is transmitted from the clutch pulley to the pickup roller. In addition, with the above configuration, drive transmission to the pickup roller can be easily performed.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A drive transmission mechanism according to the present invention will be described with reference to the illustrated example. FIG. 1 shows the structure of the pickup roller support and transmission mechanism. FIG. 2 is an explanatory view from the side, and FIG. 3 is an exploded perspective view of the drive transmission mechanism from the drive shaft to the separation roller 7 and the pickup roller 4. It is shown in the figure. In the example of the sheet feeding device shown in FIGS. 1 and 2, the sheets stacked and accommodated in the tray are taken out toward the conveyance path by the pickup roller 4, and rotated in the sheet feeding direction of the sheet sorting device 6 (see FIG. 4). Between the separate roller 7 and the retard roller 8 rotated in the direction opposite to the conveying direction,
They are separated into individual sheets and sent out for the next processing step.

In the paper feeder, the drive shaft 31 of the separate roller 7 is driven by a drive transmission mechanism of the apparatus main body (not shown), and the drive shaft 31 responds to an instruction to take out a sheet from the sheet tray. When driven, the separate roller 7 is driven. And the drive shaft 3
1 rotates, the belt 25 provided on the drive transmission device 30
The operation of pressing the pickup roller 4 against the sheet and the operation of rotating the pickup roller 4 to feed the sheet toward the separation roller 7 are performed. Further, similarly to the conventional paper feeder generally used, the sheet is fed at a speed higher than the transport speed of the paper feeder by the transport roller device 11 arranged in the transport path 10 as shown in FIG. Then, the separation roller 7 idles and the pickup roller 4 is returned to a position not in contact with the sheet so as to cope with the next sheet feeding operation.

In the drive transmission device 30 configured to perform the above-described operation, a drive shaft 31 that is supported by a frame of the device body is provided with a drive force transmission pin 32. 32 is detachable from the drive shaft 31. An oblique groove (spiral groove) 42 is provided in the separate hub 40 that can move to the left and right sides in the axial direction of the drive shaft 31.
The pin 32 is provided in the diagonal groove 42, so that the pin 32 moves in the diagonal groove 42 by the rotation of the drive shaft 31, and the pin 3 is provided on the wall surface of the groove.
2 separates the drive shaft 31 from the separate hub 4
Drive is transmitted to 0. Further, since the groove is provided obliquely, the separate hub 40 can be moved along the drive shaft 31 by the movement of the pin 32. Further, the driving force is transmitted to the mechanism of the drive system of the pickup roller 4 and the swinging system of the support arm 5 by using the belt 25 wound around the clutch pulley 35 which is transmitted by the separate hub 40. ing.

A belt 25 for transmitting drive between the pickup roller 4 and the separate roller 7 is constituted by a timing belt, and is provided on a pulley 36 disposed with respect to the drive shaft 31 and a roller shaft 50 of the pickup roller 4. Around the pulley 58. By performing the drive transmission by the belt 25, there is an advantage that the drive transmission can be easily performed without being affected by the length of the support arm 5, as compared with the case where the conventional gear transmission means is used. In other words, in the case where the drive of the separate roller 7 is transmitted to the pickup roller 4 by the idler gear as in the related art, if the stack amount of the tray 3 is increased, the step between the sheet insertion port and the tray 3 becomes large. The pickup roller 4 cannot move down to the flat portion of the tray 3, and there is a problem in that when the number of sheets that can be stacked is reduced, stress is applied to the sheets.

If the pickup roller is lowered on the flat portion of the tray in order to solve the problem of the stress applied to the sheet, the interval between the rollers 4 and 7 becomes long. It is necessary to arrange a large diameter gear. In the case where a large-diameter gear is used, there is a major problem that needs to be solved, such as the arrangement of gears for preventing the gear from protruding into the paper conveyance path. On the other hand, when the belt conduction means is used, the interval between the pickup roller 4 and the separate roller 7 can be set arbitrarily, and even when the original tray is configured to accommodate a large number of originals, The take-out action can be performed well. Further, since the belt conducting means is used, a reinforcing member can be added to an intermediate portion between the pickup roller 4 and the separate roller 7 of the arm member.

FIG. 2 is a side view of the drive transmission device.
, The pickup roller 4 is supported on a drive shaft 31 supporting the separate roller 7 via a swingable support arm 5. An arm raising means by an arm spring 27 is provided for the support arm 5, and both ends of the arm spring 27 are locked by the locking member 2a of the upper frame and the locking member 5a of the support arm 5, respectively. The operation of holding the support arm 5 in the state shown by the solid line in the figure is performed. Pickup roller 4
When the sheet stored in the sheet tray 3 is sent out, the support arm 5 is lowered by using the function of the torque limiter 60 shown in FIG. 1 and pressed onto the sheet to synchronize with the rotation of the separate roller 7. To perform the function of sending out.

In the pickup roller 4 provided in the drive transmission device, the drive shaft 3 of the separate roller 7
1 rotates the pulley 5 from the pulley 36 via the belt 25.
8 to rotate the roller shaft 50 from the spring clutch 55 via the fixed flange 51. A compression spring 63 is provided between the support arm 5 and a friction plate 61 provided on the end surface of the pulley 58 at the end of the roller shaft 50.
A torque limiter 60 made of

At the first stage when the rotation of the drive shaft 31 is transmitted to the roller shaft 50, the rotation of the drive shaft 31 is
6. The torque is transmitted to the pulley 58 via the belt 25, and between the pulley 58 and the support arm 5 there is a torque limiter 60.
, The rotational force acts in a direction to move the support arm 5 downward against the force of the arm spring 27. As a result, the support arm 5 descends,
The pickup roller 4 is pressed against a sheet stored in the tray. When the pickup roller 4 is pressed against the sheet, the lowering of the support arm 5 is prevented, so that it acts to rotate the pulley 58, and this rotation is applied to the pickup roller 4 via the spring clutch 55 and the one-way clutch 54. Transmitted, pickup roller 4
The sheet is fed.

As described above, the sheet is sent from the sheet separating device 6 to the transport roller device 11 at the downstream portion, and the leading end of the sheet is transported by the transport roller device 11. Since the transport speed of the transport roller device 11 is set to be higher than the transport speed of the separate roller 7 and the pickup roller 4 of the sheet separating device 6, the drive transmission to the separate roller 7 and the pickup roller 4 is performed by the one-way mechanism. Is stopped. Then, as a result of the rotation transmission to the pulley 36 and the pulley 58 being cut off, the lowering operation of the support arm 5 is stopped, and the support arm 5 is
With the force of 7, the pickup roller 4 swings around the drive shaft 31 in the direction of ascending, and stops at a position where it waits for the next sheet feeding operation.

The rotation of the shaft 31 is transmitted to the separate roller 7 from the pin 32 via a separate hub 40, and the drive to the pickup roller 4 is transmitted from the separate hub 40 via a clutch pulley 35 to the belt 25. Is transmitted. As shown in FIG. 1, the separate roller 7 is a roller cylinder 33 that supports a rubber roller member with respect to the drive shaft 31.
Are provided so as to freely rotate, and the roller cylinder 33 is provided.
Is provided with an engagement claw 34 on the side of.

In the separate hub 40, a driving claw member 43 is disposed at an end of the substantially cylindrical body portion 41 on the roller side.
In the outer peripheral direction of the other end of the main body, a driving claw 44 is provided so as to protrude for driving transmission to the pickup roller 4 side. The pin 32 is removably inserted into a pin insertion hole 32 a provided in the drive shaft 31, and an oblique groove 42 corresponding to the pin 32 provided in the drive shaft is provided in the main body 41 of the separate hub 40. . The separate hub 40 is configured to move in the axial direction of the drive shaft 31 by moving the pin 32 with respect to the diagonal groove 42. In a state where the separate hub 40 presses the separate roller 7, The member 43 is engaged with the engagement claw 34 of the roller cylinder 33 to transmit the rotation of the shaft to the roller. A driving claw 44 protrudingly formed on the outer peripheral portion of the separate hub 40 transmits a drive to the clutch pulley 35. The rotation of the clutch pulley 35 causes the belt 25 wound around the pulley 36 to rotate. The driving force is transmitted to the pickup roller 4.

The clutch pulley 35 includes a substantially cylindrical body 37 and a pulley 36 provided integrally with the end opposite to the roller 7. The clutch pulley 35 projects from the body 37 on the inner surface of the pulley. An engagement claw 38 is provided. As shown in FIG. 1, a separate hub 40 is provided inside the clutch pulley 35.
Is inserted into the separating roller 7 and the side of the roller 7 and the other side of the separating hub 40 are positioned between the support arms 5 on both sides. Then, by driving the drive shaft 31, the drive claw member 43 meshes with the engagement claw 34 of the separate roller 7,
The drive shaft is driven in the paper feeding direction (arrow X direction), and the rotation of the drive shaft 31 is transmitted to the separate hub 40 via the pin 32, and one end of the separate roller is regulated by the support arm 5. 7 is driven in the arrow X direction. In addition, the rotation of the separate hub 40 rotates the clutch pulley 35 via the engagement portion between the driving claw 44 and the engaged claw 38, and the drive transmission to the pickup roller 4 is performed via the pulley 36.

When the separating roller 7 is driven to separate the sheets one by one, and the sheet is fed in the conveying path,
The leading end of the sheet to be sent is arranged downstream of the conveying path,
When the sheet is transported at a high speed by the transport roller device 11 which is nipped by the transport roller device 11 rotating at a higher speed than the separation roller 7 and is rotated at the high speed,
The separating roller 7 is rotated at a speed higher than the driving speed of the driving shaft 31 by being pulled by the high-speed moving sheet. As described above, when the rotation speed of the separate roller 7 is high with respect to the drive shaft 31 rotating at a constant speed, the drive claw member 43 of the separate hub 40 and the engagement claw 34 of the roller 7 are used. Since the speed difference is generated between the driving claw member 43 and the engagement claw 34, the engagement between the driving claw member 43 and the engagement claw 34 is disengaged, and the inclined surfaces of both projections slide.

When the separating hub 40 moves away from the separating roller 7, the engagement between the driving claw 44 and the engaged claw 38 is released. Since the pin 32 provided on the drive shaft 31 moves in the direction away from the separate roller 7 along the oblique groove 42, the drive claw 44 and the engaged claw 38 are disengaged, and the rotation of the drive shaft 31 is separated. The state is not transmitted to the roller 7 and the clutch pulley 36. In the state where the sheet is fed at a high speed by the transport roller device 11 disposed at the downstream portion of the transport path, even if the drive shaft 31 is driven at a constant speed, the separation roller 7 and the pickup roller 4 The drive transmission by the drive shaft 31 is stopped.

When the sheet is fed using the drive transmission mechanism provided on the separate roller 7 shown in FIG. 3, the drive transmission by the drive shaft 31 is interrupted and the transport by the transport roller device 11 is performed. With respect to the separate roller 7 rotated by the movement of the sheet, the separate hub 40 moves in a direction away from the separate roller 7. By the movement of the separate hub 40,
The engagement between the drive claw 44 and the engaged claw 38 is released, and the drive transmission from the drive shaft 31 to the clutch pulley 35 is also cut off. When the rear end of the sheet comes off the separate roller 7, the reaction of the engaging claw 34 against the driving claw member 43 disappears, so that the pin 32 and the oblique groove 42 that receive the rotational force of the constantly rotating drive shaft 31. By the action, the separate hub 40 is pushed again to the separate roller side, and the respective claw members are engaged, so that the action of the next sheet feeding can be handled.

The drive transmission device configured as described above can be applied to the device shown in FIG. 4, and is provided in an automatic document feeder used in combination with an image reading device, and a document accommodated in a tray is provided. The image reading unit can be configured to read an image by a reading unit arranged on the conveyance path while the sheet is conveyed one by one. In the automatic document feeder 1 shown in this embodiment, a laterally substantially U-shaped transfer path 10 is disposed in the apparatus main body, and a large-diameter drive roller 14 is disposed in a curved portion of the transfer path. A document tray 3 is provided at the entrance of the road.

A pickup roller 4 is disposed above the tray 3 via a swingable support arm 5 in order to convey the document in the conveyance path 10, and a separation roller 7 and a retard roller 7 are provided downstream thereof. A sheet separating device 6 combined with a roller 8 is arranged. The sheet separating device 6 includes a separate roller 7 driven in a sheet feeding direction, similarly to a device provided in a sheet feeding device such as a general copying machine.
A retard roller 8 driven in a direction opposite to the sheet feeding direction is disposed so as to face the same. Then, when a plurality of originals taken in by the pickup roller 4 are overlapped, only the upper one is separated and sent out toward the conveying roller device 11 in the conveying path, and another original is returned to the tray side. Configure as

At the downstream side of the sheet separating device 6, there is provided a transport roller device 11 in which a drive roller 12 and a press roller 13 are combined, and a sheet is supplied toward a transport area by a large-diameter drive roller 14. The large-diameter drive roller 1
4, a platen 18 is provided in the vicinity of the lower portion of the axis of the large-diameter drive roller 14 between the portions where the press rollers 15 and 16 press the paper against the large-diameter drive roller 14. An image is read by a scanning device positioned below the image. The large-diameter drive roller 14
From the portion nipped and conveyed by the press rollers, a conveyance path is provided substantially horizontally, and a discharge roller device 17 is arranged at the end of the conveyance path, so that the document that has been read is sent out to a discharge tray.

In the transport roller device 11 disposed on the transport path 10, the upper frame 2 has a press roller 1
Press roller support unit 20 supporting each of 3 and 15
Are arranged via a stay 21 fixedly provided on the frame. The press roller support unit 20 is provided with a base bracket 23 on a stay 21 provided on the upper frame 2 of the apparatus, and at both ends of the base bracket 23,
Press rollers 13 and 15 are respectively arranged to set the nip pressure on the original in each roller device,
It is configured such that the transfer operation in the inside can be performed in a good state. The operation of pressing the pickup roller 4 against the originals (sheets) stacked on the tray 3 and the operation of applying rotation to the rollers 4 and feeding the originals toward the transport path are performed by the drive shaft 31. Separate roller 7 provided
Can be performed via a drive transmission device together with the driving of the motor.

The drive transmission device shown in the above-described embodiment is used not only for the document feeder shown in FIG. 4 but also for feeding sheets one by one from a tray in a recording paper feeder of an image forming apparatus. It can be applied to For example, even when a sheet is conveyed to the recording unit of the image forming apparatus and an image is recorded, the operation of separating and conveying the sheet from the sheet feeding tray can be performed well, and the configuration of the sheet feeding apparatus can be simplified. It is possible to Further, in the drive transmission device, in order to perform a function of transmitting the drive to the pickup roller 4 and a function of conveying the sheet by the roller, a separate component for transmitting the drive without using a pressing means such as a spring. Only a mechanism for moving the hub 40 along the drive shaft 31 is used. Therefore, in the present embodiment, the configuration of the drive transmission member in the drive transmission device can be simplified, and the problem that fine adjustment and maintenance are required as in a conventional spring clutch or the like is required. Does not occur.

[0029]

According to the apparatus of the present invention, the roller is rotatably supported with respect to the drive shaft, and the roller is moved along the drive shaft along with the normal rotation of the drive shaft. When the drive shaft is cam-coupled to the roller, the drive is transmitted to the roller, and a rotational force relatively opposite to the normal rotation acts on the drive shaft. By having a separate hub that slides to release the cam connection, the structure is simple, and strictness is not required for the manufacturing precision and the mounting precision, and the assembly work of the apparatus can be easily performed.

The separate hub is provided with a helical groove, and a pin provided on the drive shaft is housed in the groove, so that the separate hub slides along the restricted range of the groove. As a result, a simplified one-way clutch mechanism can be obtained. Further, a pickup roller is rotatably supported on the drive shaft via a swingable arm, and the separate hub has
The clutch pulley, which is engaged and disengaged by the sliding movement along the axial direction of the hub, is fitted with the clutch pulley, and the rotation of the drive shaft is transmitted from the clutch pulley to the pickup roller. Drive transmission to the pickup roller can be easily performed.

[Brief description of the drawings]

FIG. 1 is a plan view showing a configuration of an apparatus.

FIG. 2 is a side view of the apparatus of FIG.

FIG. 3 is an explanatory diagram of a drive mechanism for a separate roller provided in the apparatus of FIG. 1;

FIG. 4 is an explanatory diagram illustrating a configuration of an automatic document feeder.

[Explanation of symbols]

1 automatic document feeder, 2 upper frame, 3
Tray, 4 pickup roller, 5 support arm, 6 sheet separation device, 7 separate roller, 8 retard roller, 9 guide plate, 1
0 conveyance path, 11 conveyance roller device, 12
Drive roller, 13/15 Press roller, 14
Large-diameter drive roller, 17 discharge roller device, 18
Platen, 20 Press roller support unit, 21
Stay, 22 locking portion, 23 base bracket, 30 drive transmission device, 31 drive shaft, 3
2 pin, 33 roller cylinder, 34 engaging claw, 35 clutch pulley, 36 pulley, 3
7 torso, 38 engaged claw, 40 separate hub, 41 main body, 42 oblique groove, 43
Driving claw member, 44 Driving claw, 50 axis, 54
One-way clutch, 55 spring clutch, 58 pulley, 60 torque limiter, 6
1 Friction plate, 63 spring.

Claims (3)

[Claims] A roller is rotatably supported with respect to a drive shaft. The roller is slid along the drive shaft along with the normal rotation of the drive shaft, and is cam-coupled to the roller to transmit drive to the roller. When a rotational force relatively opposite to the normal rotation acts on the drive shaft, a separate hub that slides in a direction opposite to the normal rotation to release the cam connection is provided. A drive transmission mechanism, comprising: 2. A helical groove is provided in the separate hub, and a pin provided on the drive shaft is housed in the groove, so that the separate hub slides along a restricted range of the groove. The drive transmission mechanism according to claim 1, wherein the drive transmission mechanism is capable of being driven. 3. A pickup roller is rotatably supported on the drive shaft via a swingable arm, and a coupling meshed with the separate hub by sliding movement of the hub along an axial direction of the hub. 3. The drive transmission mechanism according to claim 1, wherein the clutch pulley to be released is fitted, and the rotation of the drive shaft is transmitted from the clutch pulley to the pickup roller.