JP2012101917A - Driving force transmission apparatus, document conveyance apparatus, image reading apparatus, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent tooth jump of a swing gear that is swingably supported when switching rotation directions of a rotary power source in a simple method.SOLUTION: A driving force transmission apparatus 100 for switching forward and reverse rotations of a roller member is arranged between the roller member and the rotary power source. The drive transmission apparatus includes: a fixed gear 36; a sway gear 31 meshing with the fixed gear 36; a sway member 32 that supports the sway gear 31 so that the sway gear 31 can move in a meshing direction with the fixed gear 36 during the forward rotation of the rotary power source; and a clutch mechanism 50 that is disposed between the fixed gear and the sway gear and that doesn't transmit the drive force during the reverse rotation of the rotary power source to the sway gear 31.

Description

  The present invention relates to a drive transmission device that drives a rocking gear using a power source that can rotate in both forward and reverse directions, and a document conveying device, an image reading device, and an image forming device using the drive transmission device.

  It has already been known to switch between two systems of power transmission paths using a swinging gear rotatably supported by a swinging lever capable of swinging a driving force from a rotational power source. However, in the conventional drive transmission device using the swing gear, when the rotation of the motor, which is the rotational power source, is reversed, tooth jump occurs between the swing gear and the gear meshing therewith. Therefore, Patent Document 1 discloses a method of fixing a swing gear using a solenoid and a plunger in a drive transmission device using a swing gear for the purpose of preventing tooth skipping when the power source is reversely rotated.

In Patent Document 1, when the rotational power source is reversed, the swing gear is fixed by using a solenoid and a plunger to prevent tooth skipping. However, since the solenoid and the plunger are used for fixing, the structure is complicated. It becomes.
It is an object of the present invention to provide a drive transmission device that can prevent tooth skipping of a swing gear supported to be swingable by a simple method when changing the rotation direction of a rotational power source. To do.
The present invention provides a document conveying device and an image forming apparatus capable of preventing a tooth jump of a swinging gear when changing the rotation direction of a rotational power source by a simple method and achieving good document conveyance. And its purpose.

  According to the present invention, a drive transmission device that is arranged between a roller member and a rotational power source and switches between normal rotation and reverse rotation of the roller member includes a fixed gear, a swing gear that meshes with the fixed gear, and a rotational power source. During forward rotation, the swinging gear is disposed between the fixed gear and the swinging gear so that the swinging gear can move in the meshing direction with the fixed gear. It has a clutch mechanism that does not transmit to the moving gear.

  In the drive transmission device according to the present invention, the clutch mechanism is interposed between the input gear to which the driving force from the rotational power source is transmitted, the output gear meshing with the fixed gear, and the input gear and the output gear. It has a ratchet part that transmits the driving force transmitted to the input gear to the output gear when the rotational power source rotates in the forward direction and does not transmit the driving force transmitted to the input gear to the output gear when the rotational power source rotates reversely. It is a feature.

  An original conveying apparatus including at least a reversing roller and a drive transmission device for rotating the reversing roller forward and backward according to the present invention is characterized in that the drive transmission device described above is provided as a drive transmission device.

  An image reading apparatus for reading an image from a document conveyed to an image reading position according to the present invention includes the document conveying device as means for conveying the document to the image reading position.

  An image reading apparatus according to the present invention forms a sheet feeding unit that feeds a recording medium, an image reading unit, and an image read by the image reading apparatus, and forms the image on a recording medium fed from the sheet feeding unit. And an image forming unit for transferring the image, and the image reading unit is configured by the image reading apparatus.

  According to the present invention, the clutch mechanism is arranged between the swinging gear supported to be swingable and the rotational power source so that the driving force at the time of reverse rotation of the rotational power source is not transmitted to the swinging gear. Therefore, the tooth skipping of the swing gear can be prevented by a simple method, and the cost can be reduced. Further, since the tooth skipping of the swing gear can be prevented, good document conveyance can be achieved.

1 is a schematic configuration diagram of a document conveying device to which a drive transmission device according to the present invention is applied. FIG. 5 is an enlarged view showing a basic configuration of the drive transmission device according to the present invention and an operating state of the drive transmission device when the rotational power source is rotated in the forward rotation direction. It is an enlarged view which shows the basic composition of the drive transmission device concerning the present invention, and shows the operation state of the drive transmission device at the time of rotation to the reverse direction of the rotation power source. It is a schematic diagram which shows the positional relationship of a rocking gear, the rocking lever which supports this, and the gear which meshes with a rocking gear. It is a disassembled perspective view of the drive transmission device provided with the clutch mechanism. It is the side view which expanded and displayed the relationship between the structure of a clutch mechanism, and the gear which meshes with the input / output gear of this mechanism. It is the upper side figure which expanded and displayed the relationship between the structure of a clutch mechanism, and the gear which meshes with the input / output gear of this mechanism. 1 is a diagram illustrating a schematic configuration of an image forming apparatus having a document conveying device according to the present invention.

  A characteristic configuration of the present invention is that when a power source is reversed in driving force switching using a rocking gear, a clutch mechanism serving as a one-way transmission mechanism is interposed between the rocking gear and the power source, thereby reversing the power source. This is to prevent the power of the time from being transmitted to the rocking gear.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. First, the basic configuration of the document conveying device 1 will be described, and then the characteristic part of the present invention will be described.

  FIG. 1 is a sectional view of a document conveying device to which a drive transmission device according to the present invention is applied. In FIG. 1, reference numeral 1 denotes an automatic document conveyance device as an example of a document conveyance device, which is attached to an upper part of an image reading device 2 such as a scanner so as to be openable and closable around a support shaft 45. The originals 6 set in page order with the image surface facing up are separated and conveyed to the image reading apparatus 2 one by one.

  The image reading apparatus 2 is provided with a slit glass 3 serving as an image reading position on the upper surface thereof, and reads an original image by passing the original 6 conveyed by the automatic original conveying apparatus 1 over the slit glass 3. . The image reading apparatus 2 can select a single-sided mode or a double-sided mode according to an instruction from an operation unit (not shown), and the operation of the automatic original conveying apparatus 1 is controlled by changing the conveying mode of the original 6 according to the set mode.

  The automatic document feeder 1 includes a pickup roller 7. The pickup roller 7 is normally on standby with a predetermined interval from the document stacking table 5, and it is detected by the document stacking sensor 8 that the document 6 is set on the document stacking table 5, and an operation (not shown) is performed. When an instruction to start reading is given on the part, the position is controlled so as to move from the standby position to the operating position where it comes into contact with the upper surface of the document 6.

  The automatic document feeder 1 includes a feed roller 9 and a reverse roller 10, and the rollers 9 and 10 separate the document 6 one by one from the top. A separation pad may be used instead of the reverse roller 10. In the automatic document feeder 1, a conveyance path (A) is formed between the guides 11 and 11a. Conveyance path (A) This is a path for conveying the document 6 separated and conveyed by the feed roller 9 constituting the separation unit onto the slit glass 3. In the automatic document feeder 1, a conveyance path (b) is formed between the conveyance path (b) guides 12 and 12a. The transport path (b) is a path for moving the document 6 transported through the slit glass 3 to the paper discharge port 13. Reference numeral 14 denotes a paper discharge tray for stacking the documents 6 discharged from the document discharge port 13.

  The automatic document feeder 1 includes a switchback conveyance path (C). The switchback conveyance path (c) is formed between the guide 16, the guides 16 a and 16 a, and the branching claw 17 provided below the document stacking table 5 and above the document tray 14. The document 6 discharged from the discharge port 13 is switched back and guided again from the rear end of the document to the transport path (A).

  The branching claw 17 is provided above the document tray 14 and is switched to the broken line position to guide the document 6 discharged from the document discharge port 13 to the switchback path (C). The document 6 is switched to the switchback path (C). When introduced into the document, the document 6 switched back in the switchback conveyance path (c) is guided from the rear end to the conveyance path (d) by switching to the solid line position.

  The conveyance path (d) is formed between the guides 18 and 18a, one end of which is joined to the conveyance path (a), and a path for conveying the switched back document 6 to the reading position again. It is.

  The reversing rollers 26 and 26a arranged in the transport path (d) are controlled in the direction of rotation by the drive transmission device 100 for switching between normal rotation and reverse rotation independently, so that the reversing rollers 26 and 26a are switched to the switchback transport path (c). The conveyed document 6 is introduced into the switchback path (c), and then reversely rotated to transport the document 6 to the transport path (d). Reference numeral 28 denotes a sensor disposed between the reading roller pair 20 disposed in front of the slit glass 3 and the reading roller pair 23 disposed in front of the paper discharge port 13, and is conveyed by the reading roller pair 20. This is for matching the leading edge of the document 6 with the timing of reading. Each roller pair is driven by a single power source (one motor).

Next, the operation of the automatic document feeder 1 will be described for each mode.
(Single-sided mode)
When a start key provided in an operation unit (not shown) is pressed in a state where the single-side mode is set, whether or not the document 6 is set on the document stacking table 5 based on a detection signal from the document stacking sensor 8 is determined. Checked. When a document set is detected, a motor (not shown) rotates forward, the pickup roller 7 descends and is pressed against the document 6, and the pickup roller 7 rotates clockwise in the drawing to feed the document. The documents 6 sent out by the pickup roller 7 are sequentially separated one by one by a feed roller 9 and a reverse roller 10 (or a separation pad). Next, when the leading edge of the document 6 is detected by the sensor 28, a reading start timing is taken, and reading of the document by the image reading device 2 is started in accordance with the leading edge of the document 6. When the sensor 28 detects the trailing edge of the document 6, the reading end timing is taken and the reading by the image reading device 2 is terminated in accordance with the trailing edge of the document 6. In the single-sided mode, since the branching claw 17 is always at the position of the solid line in the figure, the original 6 is discharged from the original discharge port 13 to the discharge tray 14 after being read and stacked with the image side down.

Although the motor is always driven, the gap between the sheets is formed by setting the linear velocity of the conveying roller 19 disposed between the feed roller 9 and the reading roller pair 20 faster than the linear velocity of the feed roller 9. . When all the originals 6 have been read, the motor reverses and the pickup roller 7 is raised and moved to the standby position.
(Double-sided mode)
When a start key provided in an operation unit (not shown) is pressed in a state where the duplex mode is set, whether or not the document 6 is set on the document stacking table 5 by a detection signal from the document stacking sensor 8 is determined. Checked. When a document set is detected, the motor rotates forward, the pickup roller 7 descends and is pressed against the document 6, and the pickup roller 7 rotates clockwise in the drawing to feed out the document 6. The documents 6 sent out by the pickup roller 7 are sequentially separated one by one by a feed roller 9 and a reverse roller 10 (or a separation pad).

  Next, when the leading edge of the document 6 is detected by the sensor 28, a reading start timing is taken, and reading by the image reading device 2 is started in accordance with the leading edge of the document 6. Further, when the tip is detected by the sensor 28, the branching claw 17 is moved to the position of the broken line in the figure, and the reverse roller 26 is rotated in the normal rotation direction (clockwise direction in the figure). When the leading edge of the document 6 is further detected by the sensor 28, the driving of the feed roller 9 and the pickup roller 7 is released by a clutch or the like, and the next document 6 is kept on standby without being fed. When the trailing edge of the document 6 is detected by the sensor 28, the reading end timing is taken, and the reading is ended by the image reading device 2 in accordance with the trailing edge of the document.

  In the automatic document feeder 1, the document 6 is conveyed from the document discharge port 13 to the switchback path (c). Then, after a predetermined time T from the detection by the sensor 28 (after a time sufficient for the trailing edge of the document to completely pass through the document discharge port 13), the branch claw 17 is switched to the solid line position in the figure, and the reverse roller 26 The rotation direction is set to the reverse rotation direction (counterclockwise direction in the figure), and the document 6 is guided to the conveyance path (d). The document 6 that has entered the conveyance path (d) is sent to the conveyance path (b). When the leading edge of the document 6 is detected by the sensor 28, the reading operation of the back surface of the document 6 is performed in the same manner as the front surface.

  When the leading edge of the document is detected by the sensor 28, the branching claw 17 is moved again to the position of the broken line in the figure, and the reverse roller 26 is rotated in the forward rotation direction. At this time, the pre-reading roller pair 20 and the reverse roller 26 rotate in opposite directions, but by providing a torque limiter on the shaft of the reverse roller 26, the pre-reading roller is followed.

  When the reading operation on the back surface is completed, it is switched back again and sent to the transport path (A). At this time, the reading operation is not performed. Even when the leading edge of the document is detected by the sensor 28, the document 6 is discharged onto the sheet discharge tray 14 with the surface facing down by setting the branching claw 17 to the solid line position.

  When the document 28 is detected by the document stacking sensor 8 when the third passage of the trailing edge of the document is detected by the sensor 28, the next document feeding operation is performed. Thereafter, the above-described operation is repeated until the document stacking sensor 8 no longer detects the document 6, thereby completing the double-sided document processing for the document on the document stacking table 5.

Next, the basic configuration of the drive transmission device 100 used in the automatic document feeder 1 will be described.
In the double-sided mode in the automatic document feeder 1 with one motor M serving as the rotational power source, it is known that there are some that use the swing gears 30 and 31 to control the rotation direction of the reversing roller 26. (For details, see Japanese Patent Application No. 2008-118716). An example of this configuration is shown in FIGS.

  FIG. 2 is a diagram of the drive transmission device 100 when the reversing roller 26 is rotating in the forward rotation direction (the clockwise direction in FIG. 1). The drive transmission device 100 includes swinging gears 30 and 31 that mesh with each other, and a swinging lever 32 as a swinging member that holds the swinging gears 30 and 31. The swing lever 32 is rotatably supported by the fulcrum gear 29. The automatic document feeder 1 includes a solenoid 33 as an electromagnetic actuator for swinging a swing lever 32 around a fulcrum gear 29. In FIG. 2, the solenoid 33 is in an off state. One end of a link 35 is pin-coupled to the movable rod 33a of the solenoid 33. On the other end of the link 35, a spring 34 serving as a biasing means is locked. For this reason, the link 35 is pulled in the direction A in FIG. 2 when the solenoid 33 is in the OFF state.

  A round hole 35 a formed in the link 35 is rotatably engaged with a convex portion 32 a provided on the fulcrum gear 29 side which is the base end side of the swing lever 32, and the link 35 is moved in the A direction by the spring 34. The swing lever 32 is configured to rotate counterclockwise by being pulled. An arc-shaped portion 32 b is formed at the upper portion of the free end of the swing lever 32. The fixed gear 36 is disposed above the arc-shaped portion 32b, and the rotation of the swing lever 32 in the counterclockwise direction is restricted (stopped) when the arc-shaped portion 32b hits the shaft 36a of the fixed gear 36. Is done. At this time, the gear 37 is rotationally driven in a counterclockwise direction in FIG. 2 by a motor (not shown) that is coaxial with the reversing roller 26, and between the gear 38 that meshes with the gear 37, and between the gear 38 and the fixed gear 36. The rotation is transmitted to the reversing roller gear 39 through the gear example constituted by the interposed clutch mechanism 50, the swinging gear 31 that meshes with the fixed gear 36, the swinging gear 30, and the fulcrum gear 29, and is coaxial with the reversing roller gear 39. The upper reverse roller 26 is rotated in the forward rotation direction.

  FIG. 3 is a view when the reverse roller 26 rotates in the reverse direction (counterclockwise direction in FIG. 1). In FIG. 3, by turning on the solenoid 33, the link 35 moves in the B direction while overcoming the pulling force of the spring 34. When the link 35 is pulled and moved in the B direction, the swing lever 32 moves clockwise around the fulcrum gear 29. The swing lever 32 is restricted (stopped) from rotating in the clockwise direction by contacting the shaft 40a of the gear 40 disposed below the swing gear 31. Further, the fixed gear 36 and the swing gear 31 are separated by the clockwise rotation. When the fixed gear 36 and the oscillating gear 31 are separated, the gear 40 and the oscillating gear 31 are engaged with each other. The rotation direction of the roller 26 can be changed to the reverse direction. In this way, it is possible to change the rotation direction of the reversing roller 26 without changing the rotation direction of the motor M1.

  As shown in FIG. 4, in this embodiment, the line Z1 connecting the rotation center A1 of the fulcrum gear 29 and the rotation center A2 of the oscillating gear 31 serving as the oscillating fulcrum, and the oscillating gear 31 and the oscillating gear 31 are connected to each other. The angle E of the line Z2 connecting the rotation centers A3 of the fixed gears 36 to be combined is set within [90 ° ± pressure angle]. Therefore, when the swing lever 32 swings, the swing gear 31 can swing smoothly without rotating the fixed gear 36. If the angle E does not fall within [90 ° ± pressure angle], the swing gear 31 moves while rotating the fixed gear 36 when the swing lever 32 swings, so the load is heavy. Therefore, since the force of the spring 34 and the solenoid 33 must be increased, the cost is increased and the size of the apparatus is increased. However, the configuration of this embodiment does not cause an increase in cost or an increase in size of the apparatus.

  As shown in FIG. 4, in this embodiment, the swinging gear 31 is set so as to bite into the fixed gear 36 by the force received by the swinging lever 32 from the motor M <b> 1. Here, if the swinging gear 31 is in the direction of escaping from the fixed gear 36 by the driving force of the motor M1, in order to prevent this, it must be held with a stronger force. This leads to the need to increase the force of the spring 34 and solenoid 33, resulting in an increase in cost and size of the apparatus. However, in this embodiment, the oscillating gear 31 is supported so as to be movable in the meshing direction with the fixed gear 36, so that the cost and the size of the apparatus are not increased.

In the automatic document feeder 1 shown in FIGS. 1 to 4, in order to raise the pickup roller 7 shown in FIG. 1 and move it to the standby position, the motor M1 is reversely rotated at the end of reading and when the main body is turned on (in FIG. 2). (Clockwise). As shown in FIG. 4, the swing gear 31 is set so as to receive a force in the direction of biting when the motor M1 rotates in the forward direction (counterclockwise in FIG. 2). On the contrary, the oscillating gear 31 receives a force in the direction of escaping. For this reason, the swing gear 31 and the fixed gear 36 may be separated from each other, and tooth skipping may occur.
(Characteristic part)
In order to solve this tooth skipping problem, in the present invention, a clutch mechanism is mounted in the drive transmission device 100 as shown in FIGS. The clutch mechanism is a one-way clutch mechanism 50. As the system, the system described in Japanese Patent Application No. 5-212654 having the simplest structure and the low idling torque is adopted. FIG. 5 shows a perspective view when the one-way clutch mechanism 50 is attached to the drive transmission device 100 shown in FIGS. 6 and 7 show a side view and a top view of only the support gear 29, the one-way clutch mechanism 50, the fixed gear 36, and the gear 38 of the drive transmission device 100 shown in FIGS.

  The one-way clutch mechanism 50 employed in the present invention is composed of three elements: an input gear 41, an output gear 42, and a ratchet portion 43. As shown in FIGS. 5 and 6, the input gear 41 meshes with the gear 38, and the output gear 42 meshes with the fixed gear 36 that meshes with the swing gear 31. When the rotational driving force from the motor M1 is input to the gear 38 and the gear 38 rotates clockwise in the drawings of FIGS. 2 to 4 (during normal rotation of the motor), the input gear 41 rotates counterclockwise in FIG. To do. When the input gear 41 rotates counterclockwise, the notch 43a formed on the ratchet 43 is inclined by the protrusion 41a formed on the side of the input gear 41 toward the ratchet 43 on the side surface. A plurality of ratchet claws 43b formed in the circumferential direction at the end opposite to the notch 43a of the portion 43 are formed in the circumferential direction on the inner ring of the output gear 42 and engaged with the plurality of claw portions 42a. It rotates counterclockwise and transmits driving force to the fixed gear 36.

  On the other hand, when the rotational driving force from the motor M1 is input to the gear 38 and the gear 38 rotates counterclockwise (when the motor rotates reversely), the input gear 41 rotates clockwise. When the input gear 41 and the convex portion 41a are integrally rotated clockwise, the convex portion 41a and the notch portion 43a are engaged, and the ratchet portion 43 is also rotated clockwise. When the ratchet portion 43 rotates clockwise, the ratchet portion 43 moves to the left side in FIGS. 6 and 7 due to the inclined surface of the ratchet pawl 43b and is separated from the output gear 42, so that the driving force is not transmitted. That is, since the output gear 42 does not rotate, it is possible to prevent tooth skipping between the rocking gear 31 and the fixed gear 36 during counterclockwise rotation.

  For this reason, the one-way clutch mechanism 50 is arranged between the swing gear 31 and the motor M1 so that the driving force during reverse rotation of the motor is not transmitted to the swing gear 31. While skipping 31 teeth can be prevented, costs can be reduced. Further, since the tooth skipping of the swing gear 31 can be prevented, the original 6 can be transported satisfactorily. By using the image reading apparatus 2 including the automatic document conveying device 1 as described above, it is possible to read a good document 6 by conveying the good document 6.

  Since the claw portion 42a of the output gear 42 is provided in the same plane as the gear tooth surface, the height of the one-way clutch mechanism 50 in the axial direction can be reduced, and the apparatus can be miniaturized. .

  The application form of the automatic document feeder 1 is not limited to the image reading device 2, but as shown in FIG. 8, a sheet feeding unit 201 for feeding a recording medium, an image reading unit 202, and an image reading unit. The image reading unit 202 of the image forming apparatus 200 includes an image forming unit 203 that forms an image read by the apparatus 202 and transfers the formed image to a recording medium fed from the paper feeding unit 201. The document conveying device 1 may be applied, and the image reading unit 202 may be configured by the image reading device 2.

  As the format of the image forming apparatus, the image of the original read by the image reading unit 202 is transferred to a recording medium by ink ejection from the ink head, or the image forming apparatus reads the image. Image forming apparatus that develops an electrostatic latent image corresponding to an image of an original document with toner as a developer, and transfers the developed toner image directly or via an intermediate transfer member to a sheet of paper or a resin film as a recording medium Is mentioned.

2 Image reading device 3 Image reading position 6 Document 26 Roller member (reversing roller)
DESCRIPTION OF SYMBOLS 31 Oscillation gear 32 Oscillation member 36 Fixed gear 50 Clutch mechanism 41 Input gear 42 Output gear 43 Ratchet part 200 Image forming apparatus 100 Drive transmission apparatus 201 Paper feeding part 202 Image reading part 203 Image forming part M1 Rotation power source P Recording medium

JP 2000-266156 A

Claims (5)

In the drive transmission device that is arranged between the roller member and the rotational power source and switches between normal rotation and reverse rotation of the roller member,
A fixed gear, a swinging gear that meshes with the fixed gear, a swinging member that supports the swinging gear so as to be movable in the meshing direction with the fixed gear when the rotational power source rotates forward, and the fixed A drive transmission device comprising a clutch mechanism that is disposed between a gear and the oscillating gear and that does not transmit a driving force when the rotational drive source is reversely rotated to the oscillating gear. The drive transmission device according to claim 1, wherein
The clutch mechanism is interposed between an input gear to which a driving force from the rotational power source is transmitted, an output gear meshing with the fixed gear, and the input gear and the output gear. It has a ratchet portion that transmits the driving force transmitted to the input gear to the output gear during forward rotation, and does not transmit the driving force transmitted to the input gear to the output gear during reverse rotation of the rotational power source. A drive transmission device. In a document conveying device provided with at least a reversing roller and a drive transmission device for reversing the reversing roller forward and backward,
An original conveying apparatus comprising the drive transmission apparatus according to claim 1 or 2 as the drive transmission apparatus. In an image reading apparatus that reads an image from a document conveyed to an image reading position,
4. An image reading apparatus comprising: the document conveying device according to claim 3 as means for conveying the document to the image reading position.   An image forming unit that forms an image read by the image reading unit and an image reading unit that feeds the recording medium, and transfers the formed image to the recording medium fed from the sheet feeding unit. An image forming apparatus comprising: the image reading device according to claim 4.

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