JP2016108135A - Drive device and image formation apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a drive device with which an image formation apparatus can be miniaturized, and to provide the image formation apparatus.SOLUTION: An input member 3 having an input pulley part 3b and an input gear part 3a is rotationally supported to an input shaft 4 of a drive device 30. The input gear part 3a of the input member 3 is engaged with a drive gear 2 to which a drive force is transmitted from a motor 1. An output gear 9a engaged with the input gear part 3a via a first clutch 9 is attached to a rotation shaft 8 of a sheet discharge roller 161. An output pulley 6 is attached to the rotation shaft 8 so as to be rotational with respect to the rotation shaft 8. A timing belt 5 is stretched over between the input pulley part 3b and the output pulley 6. A second clutch 7 is fixed to the rotation shaft 8, and a driving pawl 7a of the second clutch 7 is fitted into a drive connection hole 6a of the output pulley 6.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a drive device and an image forming apparatus.

  2. Description of the Related Art Image forming apparatuses such as copying machines, printers, facsimiles, or their combined machines are provided with many drive devices for image forming operations.

  Japanese Patent Application Laid-Open No. 2004-228561 describes a drive device that rotates a paper discharge roller, which is an output target rotating body, forward and backward. The drive device includes an input shaft that receives a rotational driving force from a motor and an output shaft that outputs the rotational driving force to a paper discharge roller. There are two drive transmission paths from the input shaft to the output shaft. One is a normal rotation drive transmission path that rotates the output shaft in the same direction as the rotation direction of the motor. This is a reverse drive transmission path that rotates in the direction opposite to the rotation direction. Each drive transmission path has a clutch serving as a drive transmission switching means. When the forward rotation drive transmission path clutch is turned on and the reverse rotation drive transmission path clutch is turned off, the output shaft rotates in the forward direction. The paper roller rotates forward. On the other hand, when the clutch of the forward drive transmission path is turned off and the clutch of the reverse drive transmission path is turned on, the output shaft rotates in the reverse direction and the paper discharge roller rotates in the reverse direction.

  In the drive device described in Patent Document 1, the forward drive transmission path clutch is provided on the output shaft, and the reverse drive transmission path clutch is provided on the input shaft. Generally, a clutch has a shorter life than a drive transmission member such as a gear or a pulley, and needs to be replaced periodically. When replacing the forward drive transmission path clutch, the output shaft is accessed, the life-long clutch is removed from the output shaft, and a new clutch is attached to the output shaft. When exchanging the clutch on the reverse drive transmission path, the input shaft is accessed, the life-long clutch is removed from the input shaft, and a new clutch is attached to the input shaft. As described above, when the forward drive transmission path clutch and the reverse drive transmission path clutch are attached to different shafts, the image forming apparatus on which the drive device is mounted is connected to both the input shaft and the output shaft. It is necessary for the worker to be able to access, and it is necessary to provide a space for this in the image forming apparatus. As a result, there is a problem that the size of the image forming apparatus is increased.

  In order to solve the above-described problem, the invention of claim 1 includes a plurality of drive transmission paths having drive transmission switching means capable of switching between a state of transmitting the driving force and a state of interrupting the transmission of the driving force, In the drive device that controls the drive transmission switching means of each drive transmission path and selectively transmits the driving force from any one of the plurality of drive transmission paths to the output target rotating body, the drive transmission switching of each drive transmission path The means is attached to the same rotating shaft.

  According to the present invention, it is possible to reduce the size of a device on which a drive device is mounted.

1 is a diagram illustrating a schematic configuration of an image forming apparatus to which a driving device according to an embodiment is applied. The schematic perspective view of the drive device. The schematic sectional drawing of the drive device. The schematic block diagram of a 1st clutch. The schematic block diagram of a 2nd clutch. (A) is a perspective view which shows a 2nd clutch and an output pulley, (b) is a perspective view of a 2nd clutch, (c) is a perspective view of an output pulley. Schematic sectional view of a conventional drive device. FIG. 6 is a schematic cross-sectional view of a drive device according to Modification 1. FIG. 9 is a schematic cross-sectional view of a driving device according to Modification 2. Schematic cross-sectional view of the driving device of Modification 3 FIG. 9 is a schematic configuration diagram of a drive device according to Modification 4. FIG. 10 is a schematic configuration diagram of a drive device according to Modification 5.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram illustrating a schematic configuration of an image forming apparatus 100 including a driving device according to an embodiment of the present invention.
As shown in FIG. 1, the image forming apparatus 100 includes an automatic document feeder 110, a reading device 120, an image forming device 130, a fixing device 140, a paper feeding device 150, a paper discharging device 160, and a refeeding device 170. Yes.

  In this embodiment, the automatic document feeder 110 has a document feeding mechanism that supports sheet-through reading. The reading device 120 is a known device that reads a document that has been sent to the reading position by the automatic document feeder 110 while it is being conveyed.

  The image forming device 130 is a known device including a photoconductor, a charging charger, an optical writing unit, a developing unit, a transfer unit, a cleaning unit, and a charge eliminating unit. In other words, the image forming device 130 forms a latent image on the photosensitive member to which a potential is applied by the charging charger by the optical writing unit, and a toner image obtained by developing the latent image on the recording paper by the transfer unit. Transcript to. The toner remaining without being transferred is cleaned by the cleaning unit, and the potential remaining on the surface of the photoreceptor is returned to zero potential by the slow current unit.

The fixing device 140 includes a pair of fixing rollers including a pressure roller 140b and a heat roller 140a.
The paper feeding device 150 pulls out the recording papers collected in the paper feeding cassette one by one and sends them to the transfer unit side of the image forming device 130.
The paper discharge device 160 can discharge the recording paper conveyed from the fixing device 140 to the paper discharge tray 163 and switch back to the paper refeed device 170 side. That is, the paper discharge device 160 includes a pair of paper discharge rollers 161a and 161b. When the paper discharge sensor 162 detects a nip state where the recording paper is sandwiched between the paper discharge rollers 161a and 161b, the paper discharge rollers 161 a and 161 b are reversed and supplied to the paper refeed device 170.

  The re-feeding device 170 causes the recording paper, which has been imaged by the image forming device 130 and is nipped between the paper discharge rollers 161 a and 161 b of the paper discharge device 160, to pass through a switchback path 171 indicated by a dotted line on the back surface thereof. The transfer direction is supplied to the image forming apparatus 130. The pair of paper discharge rollers 161a and 161b has a structure in which both of them rotate in reverse with respect to the rotation input by meshing external gears.

  Next, a drive device that rotationally drives the lower paper discharge roller 161b or the upper paper discharge roller 161a will be described. In the following description, the upper paper discharge roller 161a and the lower paper discharge roller 161b will be described as “paper discharge roller 161” when they are not distinguished from each other.

FIG. 2 is a schematic perspective view of the driving device 30 that drives the paper discharge roller 161, and FIG. 3 is a schematic cross-sectional view of the driving device 30.
The drive device 30 includes the motor 1. The motor 1 is attached to a motor attachment face plate 11. The drive gear 2 meshes with the motor gear 1 a of the motor 1. The drive gear 2 is rotatably supported by a gear shaft 2 a fixed to the side plate 12 and the motor mounting face plate 11. Further, an input shaft 4 is fixed to the side plate 12 and the motor mounting face plate 11, and an input member 3 having an input pulley portion 3b and an input gear portion 3a is rotatable on the input shaft 4. It is supported. The input gear portion 3 a of the input member 3 is engaged with the drive gear 2. The rotation shaft 8 of the paper discharge roller 161 is provided at a position shifted in the radial direction with respect to the input shaft 4, and one end side is rotatably supported by the side plate 12 via a bearing 12a. Further, an output gear 9 a that meshes with the input gear portion 3 a is attached to the rotary shaft 8 via the first clutch 9. An output pulley 6 is attached to the rotary shaft 8 so as to be rotatable with respect to the rotary shaft 8. A timing belt 5 is bridged between the input pulley portion 3b and the output pulley 6. Further, the second clutch 7 is fixed to the rotary shaft 8, and the drive claw 7 a of the second clutch 7 is fitted in the drive connection hole 6 a of the output pulley 6.

  The first clutch 9 and the second clutch 7 are connected to the control unit 20 by connectors 91 and 71, respectively. The connector 91 of the first clutch 9 and the color of the connector 71 of the second clutch 7 are different from each other, and the connector 91 of the first clutch 9 is erroneously connected to the location where the connector of the second clutch 7 is connected. It is the composition which suppresses malfunctions, such as.

FIG. 4 is a schematic configuration diagram of the first clutch 9.
As shown in FIG. 4, the first clutch 9 is an electromagnetic clutch, and includes a shaft fixing portion 9e, an electromagnetic coil portion 9d, a rotor portion 9c, an armature 9b, and the like. The shaft fixing portion 9e has an insertion hole into which the rotating shaft 8 is inserted, and the insertion hole has a D-shaped cross section. The rotating shaft 8 has a D-shaped section cut out so as to be fitted in the D-shape. A section D-shaped portion of the rotating shaft 8 extends to a location where the second clutch 7 is attached. By fitting the D-shaped section of the shaft fixing portion 9 e with the D-shaped section of the rotating shaft 8, the shaft fixing portion 9 e is fixed so as to rotate with the rotating shaft 8.

  An electromagnetic coil portion 9d is attached to the shaft fixing portion 9e so as to be rotatable with respect to the shaft fixing portion 9e. On the other hand, the rotor portion 9c is fixed to the shaft fixing portion 9e so as to rotate integrally with the shaft fixing portion 9e. An armature 9b made of a metal disk is attached to the output gear 9a, and an integrated body of the output gear 9a and the armature 9b is held by the shaft fixing portion 9e so as to be rotatable and movable within a predetermined range in the axial direction. ing. The rotor portion 9c is disposed between the electromagnetic coil portion 9d and the armature 9b.

  When the clutch is OFF, the integrated body of the output gear 9a and the armature 9b is in a free state and is in a state where it can idle with respect to the shaft fixing portion 9e. When the clutch is ON, a current flows through the electromagnetic coil portion 9d and an electromagnetic force is generated. When the electromagnetic force is generated, the armature 9b of the metal disk is attracted to the electromagnetic coil portion 9d by the electromagnetic force, and the armature 9b is attracted to the rotor portion 9c. As a result, drive transmission with the output gear 9a is possible, and the rotational driving force from the output gear 9a is transmitted to the rotary shaft 8 via the rotor portion 9c and the shaft fixing portion 9e. Rotating drive.

  The output gear 9a is preferably a helical gear that exerts a thrust force on the rotor portion 9c side when rotated by receiving a driving force from the input gear portion 3a. Thereby, the integrated body of the output gear 9a and the armature 9b can be brought into contact with the rotor portion 9c, and there is almost no time lag when the clutch is switched from the clutch OFF to the clutch ON, and the armature 9b is attracted to the rotor portion 9c. Can do.

FIG. 5 is a schematic configuration diagram of the second clutch 7. 6A is a perspective view showing the second clutch 7 and the output pulley 6. FIG. 6B is a perspective view of the second clutch 7. FIG. 6C is an output view. FIG. 6 is a perspective view of a pulley 6.
The second clutch 7 is different from the first clutch 9 in that the drive transmission member to which the armature 7b is attached is a drive connecting member 7f that performs drive transmission with an output pulley disposed on the same axis. . Other configurations are the same as those of the first clutch 9. That is, a cylindrical shaft fixing portion 7 e to which the electromagnetic coil portion 7 d and the rotor portion 7 c are attached is fixed to the rotating shaft 8. The armature 7b is attached to a drive connecting member 7f having a pair of drive claws 7a extending to the output pulley side.
As shown in FIGS. 5 and 6C, a pair of drive connection holes 6a are formed on the surface of the output pulley 6 facing the second clutch 7, and a drive connection member 7f is formed in the drive connection hole 6a. The drive claw 7a is fitted.

  In the electromagnetic clutch, the drive transmission member integrated with the armature slides toward the rotor portion 7c when the clutch is ON, and a predetermined gap is provided with respect to the shaft fixing portion so that the armature 7b is reliably attracted to the rotor portion 7c. And is attached to the shaft fixing portion. For this reason, the drive transmission member integral with the armature may be inclined with respect to the rotation shaft 8 when the clutch is OFF. When the armature is attached to the output pulley, if the output pulley is tilted with respect to the rotation shaft when the clutch is turned off, there is a possibility that a problem such as the timing belt coming off occurs.

  On the other hand, in the second clutch 7, the output pulley 6 is attached to the rotating shaft 8, and the output pulley 6 and the second clutch 7 are drivingly connected in the axial direction via the drive connecting member 7f. The output pulley 6 may be a gap that can rotate with respect to the rotary shaft 8, and the gap between the output pulley 6 and the rotary shaft 8 can be made smaller than when the output pulley 6 is slidable in the axial direction. Thereby, it can suppress that the output pulley 6 inclines with respect to a rotating shaft, and malfunctions, such as a timing belt removing, do not arise. On the other hand, since the drive connecting member 7f to which the armature 7b is attached is attached to the shaft fixing portion so as to be slidable in the axial direction, the drive connecting member may be inclined with respect to the rotation shaft when the clutch is OFF. However, even if the drive connecting member is tilted, there is no problem that the timing belt is detached.

  As shown in FIG. 3, the drive device 30 of this embodiment has two drive transmission paths from the input shaft 4 to the rotation shaft 8. The first drive transmission path 20 a includes an input gear portion 3 a for an external gear, an output gear 9 a for an external gear, and a first clutch 9. The second drive transmission path 20b includes an input pulley 3b, a timing belt 5, an output pulley 6, and a second clutch 7.

  When the first clutch 9 is turned on and the second clutch 7 is turned off, the driving force is transmitted to the rotary shaft 8 from the first drive transmission path 20a. At this time, the output pulley 6 rotates in the opposite direction to the rotation direction of the rotary shaft 8 via the input pulley portion 3 b and the timing belt 5. At this time, as described above, the second clutch 7 is OFF, and the output pulley 6 is separated from the rotating shaft 8 by the second clutch 7. Therefore, the output pulley 6 idles in the direction opposite to the rotation direction of the rotary shaft 8, and no driving force is transmitted to the rotary shaft 8 via the second clutch 7.

  When the first clutch 9 is turned off and the second clutch 7 is turned on, the rotating shaft 8 receives driving force from the second drive transmission path 20b, and the rotating shaft 8 is driven and transmitted by the first drive transmission path. And rotate in the opposite direction. At this time, the driving force for rotating the output gear 9a in the direction opposite to the rotation shaft 8 is transmitted from the input gear portion 3a. However, the first clutch 9 is OFF, and the output gear 9 a is separated from the rotating shaft 8 by the first clutch 9. Therefore, the output gear 9 a idles in the reverse direction with respect to the shaft fixing portion 9 e of the first clutch 9, and no driving force is transmitted to the rotary shaft 8 via the first clutch 9.

Switching control of the clutches 7 and 9 is performed as follows. In the following description, the first drive transmission path 20a is used as a normal rotation drive transmission path for forwardly rotating the paper discharge roller 161, and the second drive transmission path 20b is used as a normal rotation drive transmission path for reversely rotating the paper discharge roller 161. The case of using will be described.
When starting the image forming operation, the first clutch 9 is turned on, the second clutch 7 is turned off, and the motor 1 is driven. Then, the driving force is transmitted to the rotary shaft 8 through the first drive transmission path 20a, and finally the driving force is transmitted from the rotary shaft 8 to the paper discharge roller 161, so that the paper discharge roller 161 rotates forward.

  When the image forming mode is the duplex printing mode, when the paper discharge sensor 162 (see FIG. 1) detects the rear end of the recording paper conveyance direction, the first clutch 9 is switched from ON to OFF, and then the second clutch 7 is turned on. Switch from OFF to ON. As a result, the drive transmission path to the rotary shaft 8 is switched from the first drive transmission path 20a to the second drive transmission path 20b, and the paper discharge roller 161 rotates in the reverse direction. As a result, the recording paper is switched back and conveyed to the refeed device 170. When the paper discharge sensor 162 (see FIG. 1) detects the trailing edge of the recording paper in the switchback conveyance direction, the second clutch 7 is switched from ON to OFF, and then the first clutch 9 is switched from OFF to ON. As a result, the drive transmission path to the rotating shaft 8 is switched from the second drive transmission path 20b to the first drive transmission path 20a, and the paper discharge roller 161 rotates forward again. Thereafter, the recording paper that has been printed on both sides is discharged to a discharge tray 163 by a discharge roller 161.

  In FIG. 7, the first clutch 9 is provided on the rotating shaft 8 and the second clutch 7 is provided on the input shaft 4. In the configuration shown in FIG. 7, the replacement of the first clutch 9 is an operation of accessing the rotating shaft 8, removing the first clutch 9 from the rotating shaft 8, and attaching a new clutch to the rotating shaft 8. In this case, in order to allow the operator to access the rotating shaft 8, the image forming apparatus needs a space S1 shown in FIG. The replacement work of the second clutch 7 is as follows. First, the motor mounting face plate 11 is accessed and the motor mounting face plate 11 is removed. Next, after accessing the input shaft 4 and removing the input gear 3 a from the input shaft 4, the second clutch 7 is removed from the input shaft 4. Next, after attaching a new second clutch 7 to the input shaft 4, the input gear is attached to the input shaft 4. Then, the motor attachment face plate 11 is attached to the image forming apparatus. In this case, since the operator needs to access the motor mounting face plate 11 and the input shaft 4, the image forming apparatus needs a space S <b> 2. As described above, when the first clutch 9 and the second clutch 7 are attached to different shafts, at least the image forming apparatus needs a space S3, which may increase the size of the apparatus.

  On the other hand, in this embodiment, as shown in FIG. 3, the first clutch 9 and the second clutch 7 are provided on the rotating shaft 8. Thereby, if the worker accesses the rotating shaft 8, both the first clutch 9 and the second clutch 7 can be exchanged. Thereby, the space for clutch exchange work only needs to be the space S1 accessible to the rotary shaft 8. As a result, as shown in FIG. 3, for example, a member D such as a control board can be provided on the back surface of the motor mounting face plate 11, and the apparatus can be downsized.

  Further, by providing the first and second clutches on the rotating shaft 8, the input shaft 4 does not have to be supported rotatably on the motor mounting face plate 11 and the side face plate 12 via a bearing. As a result, the bearing can be eliminated, the number of parts of the device can be reduced, and the cost of the device can be reduced.

  Moreover, it is good also as a structure which provides an output shaft separately from the rotating shaft 8, attaches a 1st clutch, a 2nd clutch, an output pulley, etc. to this output shaft, and connects the output shaft with the rotating shaft 8 by coupling. In this case, when exchanging the first clutch or the second clutch, it is possible to access the output shaft, remove the output shaft from the main body of the image forming apparatus, and replace the clutch outside the image forming apparatus. Accordingly, the clutch replacement work can be easily performed in a narrow space in the image forming apparatus as compared with the case where the clutch replacement work is performed. If the lifespans of the first and second clutches are substantially the same, the output shafts to which the first clutch, the second clutch, the output pulley, and the like are attached may be replaced.

  Further, when replacing the second clutch 7 disposed on the center side of the rotation shaft with respect to the first clutch 9, it is necessary to remove the first clutch 9 from the rotation shaft 8. At this time, after attaching the new second clutch 7 to the rotating shaft 8, the first clutch 9 is attached to the rotating shaft 8. And the connector of each clutch is inserted in the connection part in an apparatus main body. At this time, if the connector 91 of the first clutch 9 and the connector 71 of the second clutch 7 are the same, the following problem may occur. That is, the connector 91 of the first clutch 9 is inserted into the connector connection portion of the second clutch 7, and the connector 71 of the second clutch 7 is inserted into the connector connection portion of the first clutch 9. This is a problem. If the connection is incorrect, the paper discharge roller rotates in the reverse direction when the paper discharge roller 161 is to be rotated forward, and the paper discharge roller is rotated in the normal direction when the paper discharge roller is reversely rotated.

  However, in the present embodiment, the connector 91 of the first clutch 9 and the connector 71 of the second clutch 7 are colored differently. Thus, the operator can determine whether the connector is the connector 91 of the first clutch 9 or the connector 71 of the second clutch 7 by looking at the color of the connector. Thereby, the incorrect connection of a connector can be suppressed. In this embodiment, identification is possible by color, but identification by shape is also possible.

In the present embodiment, the second drive transmission path 20 b is a drive transmission path using the timing belt 5. This second drive transmission path is preferably used for drive transmission when there is a risk of large load fluctuations.
When the drive transmission path is constituted by gears such as an internal gear and an external gear, when a large load fluctuation occurs in the paper discharge roller 161, the teeth may collide with each other and the teeth may be damaged or noise may be generated. is there. On the other hand, by using the timing belt, when a large load fluctuation occurs in the paper discharge roller 161, the timing belt is elastically deformed and the load fluctuation can be absorbed.

  For example, when the paper discharge roller 161b is rotated forward, the leading edge of the recording paper may abut against the paper discharge roller 161, and a large load may be generated on the paper discharge roller 161. On the other hand, when the paper discharge roller 161 is reversely rotated, the recording paper sandwiched between the paper discharge rollers 161a and 161b is switched back, so that the leading edge of the recording paper does not hit the paper discharge roller 161. Fluctuation is less than during normal rotation. In this case, the discharge roller 161 is configured to rotate forward in the case of the second drive transmission path 20b, and the discharge roller 161 is configured to rotate in the reverse direction in the case of the first drive transmission path 20a.

  Further, for example, in order to increase the productivity of the apparatus, when it is desired to perform switchback conveyance quickly, it is necessary to turn on the other clutch immediately after turning off one of the clutches. Immediately after turning off one of the clutches, the paper discharge roller rotates forward due to inertia. Immediately after turning off one of the clutches, turning on the other clutch and quickly reversing the rotation direction causes a large load. Arise. On the other hand, after the recording paper is transported back, there is a sufficient time until the recording paper reaches the paper discharge roller again. Therefore, after the other clutch is turned off and rotation of the paper discharge roller is stopped, one of the clutches is turned on and the paper discharge roller can be rotated forward again. As a result, the load fluctuation may be greater during reverse rotation than during normal rotation. Therefore, in such a case, the discharge roller 161 is configured to rotate forward in the case of the first drive transmission path 20a, and the discharge roller 161 is configured to rotate in the reverse direction in the case of the second drive transmission path 20b. To do.

  In addition, the drive transmission path using the timing belt can be expected to be quieter in the high-speed rotation region than the drive transmission path constituted only by the external gear. Therefore, it is preferable to use the second drive transmission path 20b for the drive transmission of which the rotation speed is desired to be increased between the forward rotation and the reverse rotation of the paper discharge roller.

  During the forward rotation of the paper discharge roller, the recording paper transport speed cannot be increased very much in order to obtain good fixability. However, during switchback transport, only the recording paper is transported, so increase the transport speed. Can do. Therefore, it is preferable that the discharge roller 161 has a higher rotational speed during reverse rotation than that during forward rotation. As described above, when the rotation speed of the paper discharge roller 161 during reverse rotation is increased, the paper discharge roller 161 rotates reversely when driving is transmitted via the second drive transmission path 20b using the timing belt 5. Like that. Thereby, the noise at the time of switchback conveyance can be suppressed compared with the case where the discharge roller 161 is rotated in the reverse direction in the first drive transmission path.

  Further, the drive transmission path using the timing belt 5 takes a long time from when the clutch is turned on until the driving force is transmitted to the rotary shaft 8 as compared with the drive transmission path constituted by only the gears. Therefore, it is preferable to set the timing for turning on the clutch of the drive transmission path using the timing belt 5 earlier than the timing for turning on the clutch of the drive transmission path constituted by only the gears. As a result, the rotation of the rotating shaft starts when the timing for turning on the clutch of the drive transmission path using the timing belt 5 is the same as the timing for turning on the clutch of the drive transmission path constituted by only the gears. It is possible to prevent a delay from occurring.

  Moreover, durability can be improved by comprising the 1st drive transmission path | route 20a only with an external gear. Therefore, it is preferable to use the first drive transmission path for driving in the rotation direction that is frequently used and has a long use time. The paper discharge roller is used more frequently and used for a longer time in the normal rotation for discharging the recording paper to the paper discharge tray 163 than in the reverse rotation in which the recording paper is switched back. Therefore, it is preferable that the discharge roller 161 is rotated forward when driving is transmitted through the first drive transmission path 20a.

  Further, in order to switch back, one clutch is turned off and the other clutch is turned on. Immediately after one clutch is turned off, the discharge roller 161 rotates forward due to inertia. Therefore, the recording paper is conveyed toward the paper discharge tray 163 by the inertia of the paper discharge roller 161 until the other clutch is turned on and the paper discharge roller 161 starts reverse rotation. As a result, depending on the configuration of the apparatus, the other clutch is turned on, and the trailing edge of the recording sheet is rotated by the inertial rotation of the discharge roller 161 until the discharge roller 161 starts reverse rotation. There is a risk of falling out of. When there is such a possibility, the bearing 12a that rotatably supports the rotating shaft 8 on the side plate 12 is used as a brake device that stops the rotation of the rotating shaft 8. By providing the brake device, when the recording paper is switched back, one clutch is switched from ON to OFF, and at the same time, the brake device is operated to brake the rotation of the rotary shaft 8. As a result, rotation due to inertia of the discharge roller 161 until the other clutch is turned on and the discharge roller 161 starts reverse rotation can be suppressed. Therefore, it is possible to prevent the recording paper from being conveyed to the paper discharge tray 163 due to the rotation of the paper discharge roller 161 due to the inertia before the switchback conveyance is started. Further, by providing the brake device, when the other clutch is turned on, it is drivingly connected to the rotating shaft 8 that is stopped or sufficiently decelerated. Thereby, it is possible to suppress an increase in load torque when the rotation direction of the paper discharge roller 161 is switched.

  Next, a modified example of the drive device will be described.

[Modification 1]
FIG. 8 is a schematic cross-sectional view of the drive device 30A of the first modification.
As shown in FIG. 8, the drive device 30 </ b> A of the first modification has the same configuration as the second clutch 7 for the first clutch 9.
In the drive device shown in FIG. 3, the output gear 9a is provided integrally with the first clutch (specifically, the armature 9b of the first clutch), and the shaft fixing portion of the first clutch 9 has 9e. It is attached so that it can slide in the axial direction. For this reason, the output gear 9a may be inclined with respect to the rotary shaft 8 when the clutch is OFF. Driving force is transmitted from the input gear 3a to the output gear 9a even when the clutch is OFF. Therefore, when the output gear 9a is tilted, there is a possibility that meshing vibrations and abnormal tooth wear may occur.

  On the other hand, in the first modification, the first clutch 9 is the same as the second clutch 7, and the output gear 9 a is rotatably supported on the rotating shaft 8. Like the output pulley 6, a pair of drive connection holes are provided on the surface of the output gear 9 a facing the first clutch 9, and drive claws provided in the drive connection member 9 f of the first clutch 9 in the drive connection holes. 9a is fitted.

  Thus, by making the 1st clutch 9 the same as the 2nd clutch 7, the output gear 9a can be rotatably supported by the rotating shaft 8, and it needs to be comprised so that a slide movement is possible to an axial direction. Absent. Therefore, the output gear 9a may be a clearance fit that is rotatable with respect to the rotating shaft 8, and the output gear 9a can be prevented from being inclined with respect to the rotating shaft 8. Thereby, it is possible to suppress the occurrence of meshing vibration and abnormal tooth wear.

  Further, by making the first clutch 9 and the second clutch 7 have the same configuration, the clutch used as the first clutch 9 is used as the second clutch 7 and is used as the second clutch 7. The clutch can be periodically replaced, for example, using the clutch as the first clutch 9. For example, there is a case where the other clutch deteriorates faster than the other clutch due to the usage time or the load applied to the clutch. In this case, as described above, the life of the clutch can be extended by periodically replacing the clutch.

[Modification 2]
FIG. 9 is a schematic cross-sectional view of a drive device 30B of the second modification.
In the second modification, the first clutch 9 and the second clutch 7 are attached to the input shaft 4.
In the second modification, the input shaft 4 is rotatably supported by the motor mounting face plate 11 and the side face plate 12 via bearings 11a and 12a. The input gear 3a is attached to the first clutch 9 (specifically, the armature 9b of the first clutch), and the input pulley 3b is the second clutch 7 (specifically, the armature 7b of the second clutch). Is attached. A drive idler gear 13 that meshes with the drive gear 2 is attached to the input shaft 4.

  When the first clutch 9 is ON and the second clutch 7 is OFF, the driving force is transmitted from the first drive transmission path 20 a to the rotary shaft 8. At this time, the rotary shaft 8 is rotationally driven in the direction opposite to the rotational direction of the input shaft 4. When the rotating shaft 8 rotates reversely with respect to the input shaft 4, the output pulley 6 rotates reversely, and the input pulley 3 b is driven to rotate reversely with respect to the input shaft 4. However, since the second clutch 7 is OFF, the input pulley 3 b rotates idly with respect to the second clutch 7.

  On the other hand, when the second clutch 7 is ON and the first clutch is OFF, the driving force is transmitted from the second drive transmission path 20 b to the rotary shaft 8. At this time, the rotation shaft 8 is driven to rotate in the same direction as the rotation direction of the input shaft 4. When the rotary shaft 8 rotates in the same direction as the input shaft 4, the input gear 3 a that is driven and transmitted from the output gear 9 a that rotates in the same direction as the input shaft 4 rotates with respect to the rotational direction of the input shaft 4. It is driven to rotate in the reverse direction. However, since the first clutch 9 is OFF, the input gear 3 a rotates idly with respect to the first clutch 9.

  In the second modification, when exchanging the first or second clutch, first, the motor mounting face plate 11 is accessed, and the motor mounting face plate 11 is removed from the image forming apparatus. Next, after the drive idler gear 13 is removed from the input shaft 4, the life-long clutch is removed, and a new clutch is attached to the input shaft 4. When replacing the second clutch 7, the first clutch 9 is also detached from the input shaft 4. In addition, after the motor mounting face plate 11 is removed, the input shaft 4 to which the first and second clutches are attached is moved in the axial direction so that the input shaft 4 is detached from the side face plate 12 and the clutch is formed outside the image forming apparatus. May be configured to be replaceable. Further, the input shaft 4 is moved in the axial direction together with the motor mounting face plate 11, the input shaft 4 is removed from the image forming apparatus together with the motor mounting face board 11, and the input shaft 4 is moved from the motor mounting face plate 11 outside the image forming apparatus. It may be removed.

  In the second modification, in order to replace the clutch, it is necessary to configure the image forming apparatus so that the motor mounting face plate 11 and the input shaft 4 can be accessed. As shown in FIG. 9, a space S2 is required. It becomes. However, since it is not necessary for the rotating shaft 8 to be accessible to the operator, a member or the like can be disposed outside the rotating shaft 8. As a result, compared to the case where the rotary shaft 8 and the input shaft 4 are each provided with a clutch, the space required for replacing each clutch can be reduced, and the image forming apparatus can be downsized. .

  Further, as shown in FIGS. 3 and 8, when the first and second clutches are provided on the rotating shaft 8, both the clutches are turned off and the discharge roller is temporarily rotated while the drive motor is turned on. Even when stopped, the drive transmission members of the drive transmission paths 20a and 20b (the first drive transmission path is the input gear and the output gear, the second drive transmission path is the input pulley, the output pulley, and the timing belt) Is input and continues to rotate. On the other hand, in the modified example 2, when both clutches are turned off and the rotation of the paper discharge roller is temporarily stopped with the drive motor turned on, the drive transmission member of each of the drive transmission paths 20a and 20b has a driving force. The rotation can be stopped without being input. Thereby, in the modification 2, compared with the structure which provided each clutch in the rotating shaft 8, there exists an advantage that progress of wear of the drive transmission member of each drive transmission path | route 20a, 20b can be suppressed.

[Modification 3]
FIG. 10 is a schematic cross-sectional view of a drive device 30C of the third modification.
As shown in FIG. 10, in the third modification, the second drive transmission path 20 b is configured by the input external gear 16 and the internal gear 17. In the second modification, the second drive transmission path 20b is disposed outside the first drive transmission path 20a.

  One end of the input shaft 4 is passed through the motor mounting face plate 11, and the input external gear 16 is fixed to a portion of the input shaft 4 that passes through the motor mounting face plate 11. An internal gear 17 meshes with the input external gear 16, and the internal gear 17 is attached to the second clutch 7 fixed to the rotary shaft 8. In the third modification, the second clutch 7 can be detached from the rotating shaft 8 by sliding the internal gear 17 in the axial direction. The first clutch 9 moves the second clutch 7 integral with the internal gear 17 in the axial direction and removes the second clutch 7 and the internal gear 17, then moves the first clutch 9 in the axial direction, Remove from the rotating shaft 8.

  When the first clutch 9 is ON and the second clutch 7 is OFF, the driving force is transmitted from the first drive transmission path 20 a to the rotary shaft 8. At this time, the rotating shaft 8 is driven to rotate in the direction opposite to the rotating direction of the input shaft 4. The rotary shaft 8 rotates in reverse with respect to the input shaft 4. On the other hand, the internal gear 17 receives the driving force from the input external gear 16 and rotates in the same direction as the input shaft 4, and rotates in the direction opposite to the rotary shaft 8. However, since the second clutch 7 is OFF, the internal gear 17 rotates idly with respect to the second clutch 7.

  On the other hand, when the second clutch 7 is ON and the first clutch 9 is OFF, the driving force is transmitted to the rotary shaft 8 from the second drive transmission path 20b. At this time, the rotation shaft 8 is driven to rotate in the same direction as the rotation direction of the input shaft 4. When the rotation shaft 8 rotates in the same direction as the input shaft 4, the output gear 9 a that rotates in the direction opposite to the rotation direction of the input shaft 4 rotates in the direction opposite to the rotation shaft 8. However, since the first clutch 9 is OFF, the output gear 9 a rotates idly with respect to the first clutch 9.

  In the third modification, by using the internal gear 17 in the second drive transmission path 20b, the meshing portion with the input external gear 16 can be covered with the internal gear 17, and noise generated at the meshing portion is reduced. It can be shielded by the tooth gear 17. Further, the meshing rate can be increased as compared with the external gear, and the generation of noise and vibration can be suppressed. Thereby, the silence of an apparatus can be improved. For this reason, it is preferable to use the second transmission drive path 20b for drive transmission with a higher usage frequency and a longer usage time. More specifically, the paper discharge roller 161 is used more frequently and used for a longer time in the normal rotation for discharging the recording paper to the paper discharge tray 163 than in the reverse rotation in which the recording paper is switched back. Accordingly, when driving is transmitted via the second drive transmission path 20b, the paper discharge roller 161 is rotated forward. Thereby, the silence of an apparatus can be improved effectively.

  Further, the internal gear 17 is less durable than the external gear. Therefore, it is preferable to use the second drive transmission path 20b for the drive transmission with the lower torque. For example, as described above, the clutch is quickly switched and the switchback conveyance is performed. When the load torque is larger during the switchback conveyance, when the drive transmission is performed via the second drive transmission path 20b. The paper discharge roller 161 is configured to rotate forward.

[Modification 4]
FIG. 11 is a schematic configuration diagram of a drive device 30D of the fourth modification.
In Modification 4, both the first drive transmission path 20 a and the second drive transmission path 20 b are drive transmission paths using the timing belt 5. Further, a heat roller 140a of the fixing device is provided on the input shaft 4 as an output target rotating body.

A driving force is transmitted to the input shaft 4 through the driving gear 2 meshed with the motor gear 1a and the input gear 3a fixed to the input shaft 4, and the input shaft 4 rotates at a predetermined rotational speed and is provided on the input shaft 4. The heated roller 140a rotates at a predetermined rotation speed.
The first drive transmission path 20a is composed of a first input pulley 18a, a first output pulley 18b, a first timing belt 18c and a first clutch 9 spanned between these pulleys. The first input pulley 18 a is fixed to the input shaft 4, and the first output pulley 18 b is provided in the first clutch 9 attached to the rotary shaft 8.
The second drive transmission path 20b includes a second input pulley 19a, a second output pulley 19b, and a second timing belt 19c and a second clutch 7 that are stretched over these pulleys. The second input pulley 19 a is fixed to the input shaft 4, and the second output pulley 19 b is provided in the second clutch 7 attached to the rotary shaft 8.

  When the second clutch 7 is turned off and the first clutch 9 is turned on, the rotation shaft 8 rotates at the first rotation speed in the same direction as the rotation direction of the input shaft 4 via the first drive transmission path 20a. On the other hand, when the second clutch 7 is turned on and the first clutch 9 is turned off, the driving force is transmitted to the rotary shaft 8 via the second drive transmission path 20b. Thereby, the rotating shaft 8 rotates in the same direction as the input shaft 4 at the second rotational speed different from the first rotational speed.

  As shown in FIG. 11, the diameter of the first output pulley 18b is smaller than the diameter of the first input pulley 18a, and when the driving force is transmitted through the first drive transmission path 20a, the rotation of the rotary shaft 8 The speed becomes faster than the rotational speed of the input shaft 4. On the other hand, the diameter of the second output pulley 19b is the same as the diameter of the second input pulley 19a, and when the driving force is transmitted through the second drive transmission path 20b, the rotational speed of the rotary shaft 8 is The rotational speed is the same as the rotational speed of 4. As described above, in the driving device 30D of the fourth modification, the rotation speed of the paper discharge roller 161 can be switched by switching the clutch.

  In the fourth modification, when the rear end of the recording paper in the conveyance direction passes through the fixing device 140, the rotation speed of the paper discharge roller 161 is increased by switching from the second rotation speed to the first rotation speed. Accordingly, the recording paper can be quickly discharged to the paper discharge tray 163, and productivity can be improved. Hereinafter, an example of drive control using the fourth modification will be specifically described.

At the start of the image forming operation, the second clutch 7 is turned on and the first clutch 9 is turned on to start driving the motor 1. At this time, the driving force is transmitted through the second drive transmission path 20b, and the paper discharge roller 161 rotates at a second rotational speed that is substantially the same speed as the heat roller 140a. When the paper discharge sensor 162 detects the leading edge of the recording paper in the conveyance direction, time measurement is started. Then, when the time when the trailing edge of the recording paper in the conveyance direction determined in advance by the recording paper conveyance speed comes out of the fixing device, the second clutch 7 is turned off and then the first clutch 9 is turned on. Then, the driving force is transmitted to the rotary shaft 8 through the first drive transmission path 20a, and the paper discharge roller 161 rotates at a first rotation speed that is faster than the rotation speed of the heat roller 140a. As a result, the conveyance speed of the recording paper is accelerated, and the recording paper can be quickly discharged to the paper discharge tray 163, so that productivity can be improved.
On the other hand, the heat roller 140a to which the driving force is input via the input shaft 4 continues to rotate at a constant speed even when the clutch is switched.

  In the fourth modification, the heat roller 140a and the paper discharge roller 161 are rotationally driven. Thereby, compared with the case where the paper discharge roller 161 and the heat roller 140a are rotationally driven by separate drive devices, the number of motors and drive transmission members can be reduced. As a result, it is possible to suppress the generation of noise due to motor noise of the motor and vibrations of the motor and the drive transmission member, thereby reducing noise. In addition, the number of motors and the number of drive transmission members can be reduced, and the size and cost of the apparatus can be reduced.

Further, in the fourth modification, both the first and second drive transmission paths are drive transmission paths using timing belts, so that even if the distance between the input shaft 4 and the rotary shaft 8 is long, the input pulley A drive transmission path can be formed by the output pulley, the clutch, and the timing belt. Therefore, even if the distance between the input shaft 4 and the rotary shaft 8 is large, drive transmission can be performed without increasing the number of parts. In addition, it is superior in terms of noise reduction performance and space saving in a high speed range as compared with the case where an internal gear or an external gear is used. Further, since the timing belt can be elastically deformed to absorb the load fluctuation, it is suitable for driving transmission of a rotating body that needs to quickly switch speed.

  Further, in the third modification shown in FIG. 10, the first drive transmission path 20a is used as a drive transmission path using a timing belt, and the rotation direction of the rotary shaft 8 by the first drive transmission path 20a and the second drive transmission. The rotation direction of the rotary shaft 8 by the path 20b may be the same, and the rotational speeds of the rotary shaft 8 may be different from each other. Further, the drive transmission path using the internal gear and the drive transmission path constituted only by the external gear, the rotation direction of the rotary shaft 8 by the first drive transmission path 20a, and the rotation shaft 8 by the second drive transmission path 20b. The rotation direction may be the same and the rotation speeds of the rotation shafts 8 may be different from each other. Further, both the drive transmission paths are configured only by external gears, and the rotation direction of the rotation shaft 8 by the first drive transmission path 20a is the same as the rotation direction of the rotation shaft 8 by the second drive transmission path 20b. Moreover, the rotational speeds of the rotating shafts 8 may be different from each other.

[Modification 5]
FIG. 12 is a schematic configuration diagram of a drive device 30E of the fifth modification.
This modified example 5 has three drive transmission paths. This modified example 5 is configured based on the driving device shown in FIGS. 2 and 3 described above, and is different from the driving device shown in FIGS. 2 and 3 as follows. It is.
(1) The input shaft 4 is rotatably supported by the motor mounting face plate 11 and the side face plate 12.
(2) The heat roller 140a is provided on the input shaft 4.
(3) The third drive transmission path 20c is provided.
(4) The input member 3 is attached so as not to rotate relative to the input shaft.

The third drive transmission path 20 c includes a third input pulley 22, a third output pulley 23, a third timing belt 21, and a third clutch 24. The third input pulley 22 is fixed to the input shaft 4, and the third output pulley 23 is provided in a third clutch 24 attached to the rotary shaft 8.
The diameter of the output pulley 6 of the second drive transmission path 20b is smaller than the diameter of the input pulley portion 3b. When the driving force is transmitted from the second drive transmission path 20b, the rotary shaft 8 is connected to the input shaft 4. Rotate at a faster speed. On the other hand, the diameters of the input pulley and the output pulley of the third drive transmission path 20c are the same, and when the driving force is transmitted from the third drive transmission path 20c, the rotary shaft 8 has the same speed as the input shaft 4. Rotate.

  When the driving force is transmitted from the first drive transmission path 20a to the rotary shaft 8, the first clutch 9 is turned on and the second and third clutches are turned off. At this time, the rotation shaft 8 rotates in the direction opposite to the rotation direction of the input shaft 4. When the driving force is transmitted from the second drive transmission path 20b to the rotary shaft 8, the second clutch 7 is turned on and the first and third clutches are turned off. At this time, the rotary shaft 8 is driven to rotate in the same direction as the input shaft 4 at a speed higher than that of the input shaft 4. When the driving force is transmitted from the third drive transmission path 20c to the rotary shaft 8, the third clutch 24 is turned on and the first and second clutches are turned off. At this time, the rotary shaft 8 is rotationally driven in the same direction as the input shaft 4 and at the same speed as the input shaft 4.

An example of drive control of the drive device 30E of Modification 5 will be described.
At the start of the image forming operation, the third clutch 24 is turned on, the first and second clutches are turned off, and the driving of the motor 1 is started. At this time, driving force is transmitted through the third drive transmission path 20c, and the paper discharge roller 161 rotates at the same rotational speed as the heat roller 140a.

  When the image forming mode is the single-sided printing mode, the time measurement is started when the paper discharge sensor 162 detects the leading edge of the recording paper in the conveyance direction. When the trailing edge of the recording paper conveyance speed obtained in advance based on the conveyance speed of the recording paper comes to the time when the fixing device is released, the third clutch 24 is turned off and then the second clutch 7 is turned on. Then, the driving force is transmitted to the rotary shaft 8 through the second drive transmission path 20b, and the paper discharge roller 161 rotates at a rotational speed faster than the rotational speed of the heat roller 140a. As a result, the conveyance speed of the recording paper is accelerated, and the recording paper can be quickly discharged to the paper discharge tray 163, so that productivity can be improved.

  On the other hand, when the image forming mode is the duplex printing mode, when the paper discharge sensor 162 detects the rear end of the recording paper conveyance direction, the third clutch 24 is switched from ON to OFF, and then the first clutch 9 is switched from OFF to ON. Switch to. As a result, the drive transmission path to the rotary shaft 8 is switched from the third drive transmission path 20c to the first drive transmission path 20a, and the paper discharge roller 161 rotates in the reverse direction. As a result, the recording paper is switched back and conveyed to the refeed device 170. When the paper discharge sensor 162 detects the trailing edge of the recording paper that is being switched back, the first clutch 9 is switched from ON to OFF, and then the third clutch 24 is switched from OFF to ON. As a result, the drive transmission path to the rotary shaft 8 is switched from the first drive transmission path 20a to the third drive transmission path 20c, and the paper discharge roller 161 rotates again at the same rotational speed as the heat roller 140a.

  After that, when the rear end of the recording paper in the double-sided printing direction passes through the fixing device 140, the third clutch 24 is turned off, the second clutch 7 is turned on, the recording paper feeding speed is increased, and the paper is discharged. The recording paper is discharged to the tray 163.

  In the fifth modification, the speed of the paper discharge roller 161 connected to the rotation shaft 8 can be increased without changing the rotation speed of the heat roller 140a connected to the input shaft 4, and the heat roller 140a. The rotation direction of the paper discharge roller 161 can be changed without changing the rotation direction. Accordingly, as described above, the recording paper can be switched back by the paper discharge roller 161, and the recording paper can be quickly discharged when the recording paper is discharged to the paper discharge tray 163.

  In the driving devices of the fourth and fifth modifications, the paper discharge roller 161 and the heat roller 140a are driven to rotate. However, the output target rotating body rotated by the input shaft 4 may be a rotating body that always rotates at a constant speed. That's fine. For example, examples of the output target rotating body rotated by the input shaft 4 include a transfer roller, a conveyance roller, a photoconductor, and a developing roller, but are not limited thereto. Further, the output target rotating body rotated by the rotating shaft 8 is not limited to the paper discharge roller, and may be any rotating body that is to be rotated forward / reversely or to be accelerated or decelerated.

  Further, for example, the driving device of the above-described modification 4 can be used for driving a roller for conveying a document of the automatic document feeder 110 shown in FIG. For example, a driving device can be used to drive the document discharge roller 110a and the document transport roller 110b of the automatic document feeder 110 shown in FIG. Specifically, the document conveying roller 110 b is rotated by the input shaft 4, and the document discharge roller 110 a is rotated by the rotating shaft 8. One of the first drive transmission path 20a and the second drive transmission path 20b is a drive transmission path for rotating the document discharge roller 110a at the same speed as the document conveyance roller 110b, and the other is the document discharge roller 110a. This is a drive transmission path that rotates faster than the transport roller 110b.

  First, driving force is transmitted to the document discharge roller 110a through one drive transmission path until the rear end in the document transport direction passes the reading position Y, and the document discharge roller 110a is moved at the same speed as the document transfer roller 110b. Rotate. When the rear end in the document transport direction passes the reading position Y, the clutch of one drive transmission path is turned off and the clutch of the other drive transmission path is turned on. As a result, the rotation speed of the document discharge roller 110a increases and the conveyance speed of the document sandwiched between the document discharge roller pair increases. Thereby, the image can be quickly read and the original can be discharged.

  Further, for example, the pickup roller 110 c provided so as to be able to contact and separate from the document bundle set on the document table is rotated by the input shaft 4, and the document conveying roller 110 b is rotated by the rotation shaft 8. Good. In this case, when the pickup roller 110c is brought into contact with the upper surface of the document bundle and the uppermost document is conveyed, the document conveyance roller 110b is rotationally driven at the same speed as the pickup roller 110c through one drive transmission path. When the leading end of the document transport direction reaches the document transport roller 110b and the document is transported by the document transport roller 110b, the pickup roller 110c is separated from the document bundle. When the pickup roller 110c is separated from the original bundle, the clutch of one drive transmission path is turned off and the clutch of the other drive transmission path is turned on. As a result, the rotation speed of the document transport roller 110b increases, and the document transport speed increases. As a result, the document can be quickly conveyed to the reading position, and productivity can be improved.

  As described above, by using the driving device of the modified example 4 for the automatic document feeder 110, a space accessible to the rotating shaft 8 may be provided in the automatic document feeder 110 for exchanging the clutch. . Therefore, the automatic document feeder 110 can be reduced in size as compared with the case where the clutch is disposed on each of the rotating shaft 8 and the input shaft 4.

What has been described above is an example, and the present invention has a specific effect for each of the following aspects.
(Aspect 1)
A plurality of drive transmission paths having a drive transmission switching means such as a clutch capable of switching between a state of transmitting driving force and a state of interrupting transmission of driving force, and controlling the drive transmission switching means of each drive transmission path In the driving apparatus that selectively transmits the driving force from any one of the plurality of driving transmission paths to the output target rotating body such as the paper discharge roller 161, the driving transmission switching means of each driving transmission path is the same rotating shaft 8. Attached to.
According to this, since the drive transmission switching means such as the clutch of each drive transmission path is attached to one rotation shaft, the worker can access only the rotation shaft to which the drive transmission switching means is attached. If a device on which the driving device 30 is mounted, such as a forming device, is configured, the drive transmission switching means of each drive transmission path can be exchanged. Thereby, compared with the structure which attached the drive transmission switching means to the mutually different rotating shaft, size reduction of the apparatus by which a drive device is mounted can be achieved.

(Aspect 2)
In (Aspect 1), at least one of the plurality of drive transmission paths is a reverse drive that rotates the output target rotating body such as the paper discharge roller 161 in a direction opposite to the direction when the driving force is transmitted through the predetermined drive drive path. It is a transmission path.
According to this, by controlling the drive transmission switching means such as the clutch of each drive transmission path, the output target rotating body such as the paper discharge roller 161 can be driven to rotate forward / reversely.

(Aspect 3)
In (Aspect 1) or (Aspect 2), at least a drive transmission path having the largest load fluctuation to the drive transmission path among a plurality of drive transmission paths is configured to perform drive transmission using a belt such as a timing belt. did.
According to this, as described in the embodiment, when a load change occurs during drive transmission, the load can be absorbed by elastic deformation of the belt. Therefore, the drive transmission member constituting the drive transmission path may be damaged by an impact or the like when the drive transmission is interrupted by the drive transmission switching means such as the clutch to the state where the drive force is transmitted. Can be suppressed.

(Aspect 4)
In any one of (Aspect 1) to (Aspect 3), among the plurality of drive transmission paths, at least the drive transmission path that rotates the output target rotating body such as the paper discharge roller 161 the fastest is a belt such as a timing belt. It used to perform drive transmission.
According to this, as described in the embodiment, the drive transmission path using the belt is superior in quietness in the high speed range as compared with the case where the gear is used. Therefore, by using a belt for a drive transmission path that rotates at least the rotating shaft 8 among a plurality of drive transmission paths, noise can be reduced as compared with the case of using gears.

(Aspect 5)
In any one of (Aspect 1) to (Aspect 4), at least one of the plurality of drive transmission paths is configured to perform drive transmission using an internal gear.
According to this, as described in the modification example 3, by using the internal gear, it is possible to increase the meshing rate as compared with the case of using the external gear, and to suppress the occurrence of rotation unevenness and noise / vibration. be able to.

(Aspect 6)
In any one of (Aspect 1) to (Aspect 5), at least one of the plurality of drive transmission paths is constituted only by an external gear.
According to this, as explained in the embodiment, the external gear has higher durability than the internal gear and the timing belt. Therefore, at least one of the plurality of drive transmission paths can be configured with only the external gear, whereby the durability of the drive transmission path can be enhanced.

(Aspect 7)
In any one of (Aspect 1) to (Aspect 6), the drive transmission member such as the output gear 9a provided in the drive transmission switching means such as the clutch is connected to the drive transmission member such as the input gear portion 3a adjacent in the radial direction. Has been.
According to this, the driving force transmitted from the drive transmission member such as the input gear portion 3a adjacent in the radial direction can be cut off by the drive transmission switching means such as the clutch or transmitted to the rotary shaft 8. .

(Aspect 8)
In (Aspect 7), the drive transmission switching means such as a clutch is connected to a drive transmission member such as the output gear 9a in the axial direction, and the drive transmission member has a thrust force in the connection direction with the drive transmission switching means. A working helical gear.
According to this, as explained in the embodiment, the drive transmission member such as the output gear 9a is a helical gear that has a thrust force acting in the connecting direction with the drive transmission switching means. It can be brought into contact with a connecting portion such as the rotor portion 9c of the transmission switching means, and there is almost no time lag when switching from the state where the transmission of the driving force is cut off to the state where the driving force is transmitted, and it is connected to the driving transmission member. can do.

(Aspect 9)
In any one of (Aspect 1) to (Aspect 8), the drive transmission switching of which drive transmission path is connected to the connection connector of each drive transmission switching means connected to a control means such as a control unit that controls the drive transmission switching means such as a clutch. Identification means (in this embodiment, the colors are different from each other) is provided for identifying whether the connection connector of the means.
According to this, as described in the embodiment, it is possible to grasp which drive transmission path is the drive transmission switching unit of the connection connector by the identification unit of the connection connector. Thereby, the operator can connect to the connected portion corresponding to the connection connector without making a mistake, and can suppress erroneous connection of the connection connector. The identification means can be realized by making the colors of the connection connectors different from each other, making the marks different from each other, and making the shapes different from each other.

(Aspect 10)
In any one of (Aspect 1) to (Aspect 9), the drive transmission switching means such as the clutch of each drive transmission path has the same shape.
According to this, as described in the first modification, the drive transmission switching means in the drive transmission path where the deterioration of the drive transmission switching means such as the clutch progresses quickly, and the drive transmission path where the deterioration of the drive transmission switching means progresses slowly. This drive transmission switching means can be periodically replaced, and the life of the drive transmission switching means can be extended.

(Aspect 11)
In any one of (Aspect 1) to (Aspect 10), at least one of the plurality of drive transmission paths is a drive transmission path for performing drive transmission using a belt such as the timing belt 5, and the drive transmission is performed using the belt. Drive transmission path drive transmission switching means for performing drive transmission without using a belt at a timing for switching from a state in which the transmission of the driving force of the drive transmission switching means such as a clutch of the drive transmission path to be performed is interrupted to a state in which the driving force is transmitted. It was faster than the above timing of switching.
According to this, as described in the embodiment, it is possible to prevent a drive start delay when a driving force is transmitted through a drive transmission path that performs drive transmission using a belt.

(Aspect 12)
In any one of (Aspect 1) to (Aspect 11), the drive transmission switching means is an electromagnetic clutch.
According to this, the driving force can be transmitted by turning on the electromagnetic clutch, and the driving force can be blocked by turning off the electromagnetic clutch.

(Aspect 13)
In any one of (Aspect 1) to (Aspect 12), brake means such as a brake device for stopping the rotation of the output target rotating body such as the paper discharge roller 161 is provided.
According to this, as described in the embodiment, the driving force switching means such as the clutch of the driving transmission path that transmits the driving force to the rotating shaft is changed from the state where the driving force is transmitted to the state where the driving force is cut off. When switching and switching the driving force switching means of another driving transmission path from the state where the driving force is cut off to the state where the driving force is transmitted, the output target rotating body such as the paper discharge roller rotates due to inertia. It can be stopped with brake means.

(Aspect 14)
(Aspect 1) to (Aspect 13) An image forming apparatus including any one of the driving devices.
According to this, as described in the embodiment, it is possible to reduce the size of the image forming apparatus.

1: Motor 2: Drive gear 3: Input member 3a: Input gear, input gear portion 3b: Input pulley, input pulley portion 4: Input shaft 5: Timing belt 6: Output pulley 6a: Drive connection hole 7: Second clutch 7f : Driving connecting member 8: rotating shaft 9: first clutch 9 a: output gear 9 f: driving connecting member 11: motor mounting face plate 12: side face plate 13: driving idler gear 16: input external gear 17: internal gear 18 a: first input Pulley 18b: first output pulley 18c: first timing belt 19a: second input pulley 19b: second output pulley 19c: second timing belt 20: control unit 20a: first drive transmission path 20b: second transmission drive path 20c : Third drive transmission path 21: Third timing belt 22: Third input pulley 23: Third output pulley 24: Third clutch 30: Drive device 71: Connection Motor 91: connector 100: Image forming apparatus 110: an automatic document feeder 140: fixing device 140a: heat roller 160: sheet discharging device 161: discharge roller 162: discharge sensor 163: discharge tray

JP 2014-173676 A

Claims (14)

A plurality of drive transmission paths having drive transmission switching means capable of switching between a state of transmitting driving force and a state of interrupting transmission of driving force, and controlling the drive transmission switching means of each drive transmission path, In the driving apparatus that selectively transmits the driving force to the output target rotating body from any one of the drive transmission paths,
A drive apparatus characterized in that the drive transmission switching means of each drive transmission path is attached to the same rotating shaft. The drive device according to claim 1,
At least one of the plurality of drive transmission paths is a reverse drive transmission path for rotating the output target rotating body in a direction opposite to that when the driving force is transmitted through the predetermined drive drive path. apparatus. The drive device according to claim 1 or 2,
A drive device configured to perform drive transmission using a belt at least on a drive transmission path having a largest load fluctuation to the drive transmission path among a plurality of drive transmission paths. The drive device according to any one of claims 1 to 3,
A drive device characterized in that at least a drive transmission path for rotating the output target rotating body at a fastest speed among the plurality of drive transmission paths is configured to perform drive transmission using a belt. The drive device according to any one of claims 1 to 4,
At least one of the plurality of drive transmission paths is configured to perform drive transmission using an internal gear. The drive device according to any one of claims 1 to 5,
At least one of the plurality of drive transmission paths is constituted by only an external gear. The drive device according to any one of claims 1 to 6,
The drive transmission member provided in the drive transmission switching means is connected to a drive transmission member adjacent in the radial direction. The drive device according to claim 7, wherein
The drive transmission switching means is connected to the drive transmission member in the axial direction,
The drive device according to claim 1, wherein the drive transmission member is a helical gear in which a thrust force acts in a connecting direction with the drive transmission switching means. The drive device according to any one of claims 1 to 8,
An identification means for identifying which drive transmission path is the connection connector of the drive transmission switching means is provided on the connection connector of each drive transmission switching means connected to the control means for controlling the drive transmission switching means. A drive device. The drive device according to any one of claims 1 to 9,
A drive device characterized in that the drive transmission switching means of each drive transmission path has the same shape. The drive device according to any one of claims 1 to 10,
Among the plurality of drive transmission paths, at least one is a drive transmission path that performs drive transmission using a belt,
The timing of switching from the state where the drive force transmission of the drive transmission switching means of the drive transmission path that transmits the drive using the belt to the state that transmits the drive force is switched to the state of the drive transmission path that transmits the drive without using the belt. A drive device characterized in that the drive transmission switching means is set earlier than the switching timing. The drive device according to any one of claims 1 to 11,
The drive device, wherein the drive transmission switching means is an electromagnetic clutch. The drive device according to any one of claims 1 to 12,
A drive device comprising a brake means for stopping the rotation of the output object rotating body.   An image forming apparatus comprising the driving device according to claim 1.

Images