JP4807273B2 - Clutch device and image forming apparatus having the same - Google Patents

Description

  The present invention relates to a clutch device suitable for a paper feeding device such as an electronic copying machine, a printer, or a multifunction machine thereof, and an image forming apparatus equipped with the paper feeding device including the clutch device.

  In an electrophotographic image forming apparatus, a laser beam modulated with an image signal is projected onto a charged image carrier to form an electrostatic latent image of the image, and the formed electrostatic latent image is developed with toner. Thus, a toner image is formed on the image carrier. Next, the toner image is transferred onto a recording sheet, the toner image transferred onto the recording sheet is fixed, and discharged to a discharge tray.

  In such an image forming apparatus, a paper feeding device is used to feed recording paper. FIG. 7 is a cross-sectional view illustrating an example of the configuration of a conventional paper feeding device. The paper feeding device 100 stacks recording sheets P that are rotatably supported around a rotating shaft 101a. Driven cams 102 provided at the left and right ends of the recording paper conveyance direction, a drive cam 103 that contacts the driven cams 102 to move the stacking plate 101 up and down, a coil spring 104 disposed on the back surface of the stacking plate 101, and a stacking A paper feed roller 105 disposed above the plate 101, a paper tray 106 for feeding the fed recording paper P, a transport roller 107 for transporting the fed recording paper P, a drive cam 103 and a paper feed roller 105 are shown in the figure. And a drive gear 109 that is rotationally driven via a gear train that does not.

  The operation of the paper feeder 100 will be briefly described. In the standby state, the driven cams 102 provided at the left and right ends of the stacking plate 101 in the conveying direction come into contact with the driving cam 103, the stacking plate 101 is pushed down against the biasing force of the coil spring 104, and Is not in contact with the paper feed roller 105.

  When a paper feed command is output from a control device of the image forming apparatus (not shown), the paper feed roller 105 starts to rotate and the drive cam 103 is rotated by the rotation of the drive gear 109. Via the driving cam 103 and the driven cam 102, the stacking plate 101 is rotated around the rotation shaft 101 a by the urging force of the coil spring 104 and rises. The uppermost recording paper P stacked on the stacking plate 101 comes into contact with the paper feed roller 105, and the uppermost recording paper P is fed and transported to the image forming unit (not shown) by the transporting roller 107 through the paper tray 106. Is done. Further, since the rotation of the drive cam 103 pushes down the driven cam 102 against the urging force of the coil spring 104, the stacking plate 101 of the paper feed tray returns to the standby state. With the above operation, feeding of one recording sheet P is completed.

  In the paper feeding device having the above configuration, when the driving cam 103 is rotated by a paper feeding command, the stacking plate 101 of the paper feeding tray is raised by the biasing force of the coil spring 104. At this time, the left and right end portions of the stacking plate 101 in the transport direction The cam surface of the drive cam 103 is kicked and rotated by the tip of the driven cam 102 provided on the sheet (hereinafter, this rotation is referred to as “first rotation”), and the paper feed roller 105 driven in conjunction with the drive cam 103 is also a predetermined one. In addition to the rotation, the sheet is pre-rotated in the sheet feeding rotation direction, and these movements are considered to cause a large impact sound. Further, in the ratchet mechanism composed of a claw wheel and a locking claw incorporated in a clutch mechanism disposed in a drive source that drives the drive cam 103 and the paper roller 105, the claw wheel is rotated by the above-described first rotation. As a result, there was an inconvenience that an abnormal sound of nail skipping occurred.

As a countermeasure, a member with a high coefficient of friction is attached to the contact surface of the drive cam that the driven cam of the loading plate of the paper feed tray contacts to prevent the drive cam from rotating forward, and an impact sound is generated when the load plate rises. A technique for preventing the above has been proposed (see Patent Document 1).
JP-A-5-301644

  However, the high friction coefficient member attached to the drive cam is expensive, and the friction coefficient between the drive cam and the driven cam becomes high, so that the rotational torque of the drive cam becomes high.

  The present invention solves the above-described problem, and even if the drive cam rotates by the paper feed command and the stacking plate of the paper feed tray rises, the front rotation of the drive cam and the paper feed driven in conjunction therewith To provide a clutch device suitable for a paper feeding device and an image forming apparatus including the same, which can prevent the roller from rotating forward and suppress the generation of a large impact sound and the ratchet mechanism. It is intended.

The present invention solves the above-mentioned problems, and the invention according to claim 1 is a clutch device of a paper feeding device that conveys a recording member to an image forming unit, and the clutch device is an input shaft connected to a power source. And an output shaft connected to the paper feed roller, a planetary gear mechanism disposed between the input shaft and the output shaft, and a ratchet mechanism disposed on the output shaft of the planetary gear mechanism, The ratchet mechanism has a first claw wheel having a locking claw piece fixed on the output shaft, and a locking claw piece having a locking direction opposite to the locking claw piece of the first claw wheel. And a second claw wheel that frictionally contacts the first claw wheel, and a locking claw device that locks the locking claw piece of the first and second claw wheels. This is a clutch device of a paper feeding device.

  The second claw wheel is in frictional contact with the first claw wheel, and the second claw wheel can rotate independently of the first claw wheel.

  Further, the locking claw device is set to a locking position and a locking release position on the locking claw pieces of the first and second claw wheels by a solenoid that operates in response to a paper feed command.

  Then, the angular position θ2 with respect to the rotation axis of the adjacent locking claw piece of the second claw wheel may be set smaller than the angular position θ1 with respect to the rotation axis of the adjacent locking claw piece of the first claw wheel. .

  According to a fifth aspect of the present invention, there is provided an image forming apparatus equipped with a paper feeding device including the clutch device according to any one of the first to fourth aspects.

  According to the present invention, at the start of the paper feeding operation, when the loading plate of the paper feeding device rises and the driven cam comes into contact with the drive cam, the paper feed roller feeds when the driven cam is kicked by the driven cam. It is possible to prevent or suppress the pre-rotation in the rotation direction, the generation of the impact sound caused by these movements, and the generation of abnormal noise of the ratchet mechanism. In addition, since it is possible to prevent or suppress the generation of impact noise and abnormal noise, it is possible to omit a member having a high friction coefficient attached to the surface of the drive cam in the conventional configuration, and to reduce the manufacturing cost. it can.

  Embodiments of the present invention will be described below. 1 and 2 are cross-sectional views of the configuration of the paper feeding device 10 according to the present invention as seen from the side, FIG. 1 shows a paper feeding standby state, and FIG. 2 shows a paper feeding state.

  The sheet feeding device 10 is in contact with a stacking plate 11 on which recording paper P supported rotatably around a rotation shaft 11a, a driven cam 12 provided at the left and right ends of the stacking plate 11, and a driven cam 12 are contacted. A drive cam 13 for moving the stacking plate 11 in the vertical direction, a coil spring 14 disposed on the back surface of the stacking plate 11, a paper feed roller 15 disposed above the stacking plate 11, and a recording sheet as a fed recording member The webbing table 16 for separating P, the conveyance roller 17 and the conveyance roller 18 for conveying the fed recording paper P, the drive cam 13, the paper supply roller 15, and the conveyance rollers 17 and 18 are rotationally driven via a gear train (not shown). A drive gear 19 and a clutch device 20 connected to the drive gear 19 described later are included. In FIGS. 1 and 2, the clutch device 20 includes only a claw wheel 31 a and a locking claw device 31 b that constitute a ratchet mechanism 31 that is a part of the clutch device 20.

  The operation of the paper feeder 10 will be briefly described. In the paper feed standby state shown in FIG. 1, the driven cams 12 provided at the left and right ends of the stacking plate 11 in the conveying direction come into contact with the driving cam 13, and the stacking plate 11 is pushed against the urging force of the coil spring 14. The recording paper P that is lowered and stacked on the stacking plate 11 is not in contact with the paper feed roller 15.

  When a paper feed command is output from a control device of the image forming apparatus (not shown), the drive gear 19 is rotated by the drive cam 13 while the feed roller 15 starts rotating via the clutch device 20 and a gear train (not shown). Rotate. The rotation of the driving cam 13 releases the push-down of the stacking plate 11 of the paper feed tray via the driven cam 12, and the stacking plate 11 is rotated around the rotating shaft 11 a by the urging force of the coil spring 14. The sheet feeding state shown in FIG. 2 shows this state.

  As the stacking plate 11 is raised, the uppermost recording paper P stacked on the stacking plate 11 comes into contact with the paper feed roller 15, and the uppermost recording paper P is fed, and the transport roller 17, 18 is conveyed to an image forming unit (not shown). Further, since the rotation of the drive cam 13 pushes down the driven cam 12 against the urging force of the coil spring 14, the stacking plate 11 of the paper feed tray returns to the paper feed standby state shown in FIG. With the above operation, feeding of one recording sheet P is completed.

  The clutch device will be described. FIG. 3 is a diagram schematically illustrating the configuration of the clutch device 20, FIG. 3 (a) is a cross-sectional view thereof, and FIG. 3 (b) is a front view of the planetary gear mechanism 21 in the clutch device 20.

  The clutch device 20 includes a planetary gear mechanism 21 and a ratchet mechanism 31 that locks the inner sun gear 21d of the planetary gear mechanism 21, and the ratchet mechanism 31 includes a claw wheel 31a and a locking claw device 31b. The ratchet mechanism 31 has a configuration in which the ratchet mechanism 31 does not become free to rotate in the drive transmission direction even when the ratchet wheel is driven in the drive rotation direction by an external force in order to prevent the rotation of the drive cam and the paper feed roller. This will be described in detail later.

  In the planetary gear mechanism 21, an outer sun gear 21b that is an internal gear is connected to an input shaft 21a, and an inner sun gear 21d that is an external gear is connected to a shaft 21g that is disposed coaxially with the input shaft 21a. A plurality (three in the figure) of planetary gears 21c are arranged between the outer sun gear 21b and the inner sun gear 21d, and the rotation shaft of the planetary gear 21c is rotatably supported by the carrier 21e. The central axis is an output shaft 21f.

  The first claw wheel 31a1 is fixed to the shaft 21g of the inner sun gear 21d, and the second claw wheel 31a2 is disposed in frictional contact with the first claw wheel 31a1, and the first claw wheel 31a1 and the second claw wheel A locking claw device 31b can be engaged with the locking claw 31a2. The locking claw device 31b is operated by a solenoid 31c, and sets the first claw wheel 31a1 and the second claw wheel 31a2 to the locking and locking release positions.

  When transmitting the rotation of the input shaft 21a to the output shaft 21f (clutch device OFF), the solenoid 31c is operated, and the locking claw device 31b is attached to the first claw wheel 31a1 fixed to the shaft 21g of the inner sun gear 21d. The inner sun gear 21d is fixed by locking. The outer sun gear 21b is rotated by the rotation of the input shaft 21a, the carrier 21e is rotated through the rotation of the planetary gear 21c, the output shaft 21f that is the central axis of the carrier 21e is rotated, and the rotation of the input shaft 21a is transmitted to the output shaft 21f. The

  In the case of transmission interruption (clutch device ON) in which the rotation of the input shaft 21a is not transmitted to the output shaft 21f (the clutch device is ON), the solenoid 31c is turned OFF and the latching pawl of the first pawl wheel 31a1 fixed to the shaft 21g of the inner sun gear 21d. The locking by the device 31b is released, and the inner sun gear 21d is set to be rotatable. The outer sun gear 21b is rotated by the rotation of the input shaft 21a, the planetary gear 21c is rotated, and the inner sun gear 21d is also rotated. However, the carrier 21e is stopped by the load of the output shaft 21f that is the central axis of the carrier 21e. The output shaft 21f, which is the central axis of the carrier 21e, stops, and the rotation of the input shaft 21a is not transmitted to the output shaft 21f.

  Next, the ratchet mechanism 31 will be described. In a normal ratchet mechanism, when the claw wheel is driven in the drive transmission direction by external force, the locking claw piece of the locking claw device is detached from the claw wheel and allows driving in the drive transmission direction by the external force of the claw wheel, The drive transmission direction is provided with a configuration that is free of rotation. However, in the present invention, in order to prevent the rotation of the drive cam and the paper feed roller, even if the ratchet wheel is driven in the drive rotation direction by an external force, it has a configuration in which the rotation is not free in the drive transmission direction.

  4 is a perspective view for explaining the configuration of the ratchet mechanism 31, and FIGS. 5 and 6 are front views for explaining the relationship between the ratchet mechanism 31 and the engaging claws.

  As shown in FIGS. 4, 5, and 6, the ratchet mechanism 31 has a claw wheel 31 a that includes a first claw wheel 31 a 1 having a locking claw piece and a locking claw piece of the first claw wheel 31 a 1. A second claw wheel 31a2 provided with a locking claw piece whose locking direction is opposite to each other is configured by overlapping two sheets. The locking claw pieces of the first claw wheel 31a1 and the second claw wheel 31a2 are arranged to be locked to the same locking claw device 31b, and the first claw wheel 31a1 is a shaft 21g of the inner sun gear 21d. The second claw wheel 31a2 is in frictional contact with the first claw wheel 31a1.

  The locking claw device 31b can be locked to both the locking claw piece of the first claw wheel 31a1 and the second claw wheel 31a2 provided with a locking claw piece having the opposite locking direction. It has a locking claw.

  The second claw wheel 31a2 that is brought into frictional contact with the first claw wheel 31a1 normally rotates together with the first claw wheel 31a1, but when a large load is applied to the second claw wheel 31a2, the first claw wheel 31a2 rotates. The vehicle 31a1 can rotate independently of the vehicle 31a1.

  With this configuration, when a paper feed command is output, the solenoid 31c is turned ON, and the locking claw piece of the first claw wheel 31a1 fixed to the shaft 21g of the inner sun gear 21d is locked to the locking claw device 31b. The inner sun gear 21d is fixed, and the carrier 21e rotates. The output shaft 21f, which is the central axis of the carrier 21e, rotates, and the rotation of the input shaft 21a is transmitted to the output shaft 21f, causing the drive cam 13 to rotate. The stacking plate 11 of the sheet feeding tray is raised by the urging force of the coil spring 14, the uppermost recording sheet P stacked on the loading plate 11 contacts the sheet feeding roller 15, and the uppermost recording sheet P is fed. Then, the sheet is conveyed to an image forming unit (not shown) by conveying rollers 17 and 18 after passing through the rack 16 (see FIG. 5).

  When the loading plate 11 is raised, the cam surface of the drive cam 13 is kicked by the tip of the driven cam 12 provided at the left and right ends of the loading direction of the loading plate 11 and tries to rotate (forward rotation) in the direction of arrow a. The locking claw piece of the second claw wheel 31a2 fixed to the output shaft 21f that drives the driving cam 13 is locked to the locking claw device 31b, and the rotation of the driving cam 13 in the direction indicated by the arrow a (below) (Rotation) is prevented (see FIG. 6).

  When the paper feed command is canceled (paper feed is stopped), the solenoid 31c is turned OFF, and the locking claw piece of the first claw wheel 31a1 fixed to the shaft 21g of the inner sun gear 21d is locked to the locking claw device 31b. The inner sun gear 21d is set to be rotatable. The outer sun gear 21b is rotated by the rotation of the input shaft 21a, the planetary gear 21c is rotated, and the inner sun gear 21d is also rotated. However, the carrier 21e is stopped by the load of the output shaft 21f that is the central axis of the carrier 21e. The output shaft 21f, which is the central axis of the carrier 21e, stops, the drive cam 13 stops rotating, and paper feeding is stopped.

  The angular position θ2 with respect to the rotation axis of the locking claw piece of the second claw wheel 31a2 may be set smaller than the angular position θ1 with respect to the rotation axis of the adjacent locking claw piece of the first claw wheel 31a1. Thereby, even if the first claw wheel 31a1 is driven in the driving rotation direction by the previous rotation of the driving cam 13 and the paper feed roller 15 due to the kicking of the driving cam 13, the second claw wheel 31a2 rotates early. Can be prevented.

  According to the sheet feeding device having the ratchet mechanism described above, it is possible to prevent the rotation of the sheet feeding roller in the sheet feeding rotation direction caused by the drive cam colliding with the driven cam when the stacking plate on which the recording sheets are stacked rises or It is possible to suppress the occurrence of an impact sound caused by these movements and the generation of an abnormal sound due to the ratchet mechanism. This eliminates the need to attach a member having a high coefficient of friction to the contact surface of the drive cam with which the driven cam of the loading plate of the paper feed tray contacts.

  Further, the sheet feeding device provided with the ratchet mechanism described above can be applied to a sheet feeding device of a conventional image forming apparatus as shown in FIG.

  In the sheet feeding device of the image forming apparatus, the clutch device of the sheet feeding device can prevent the generation of an impact sound that occurs when the stacking plate on which recording sheets are stacked rises and the generation of abnormal noise due to the ratchet mechanism.

Sectional drawing which shows the paper-feed standby state of the paper feeder which concerns on this invention. Sectional drawing which shows the paper feeding state of the paper feeder which concerns on this invention. The figure which illustrates the structure of a clutch apparatus typically. The perspective view explaining the structure of a ratchet mechanism. The front view explaining the relationship between the ratchet mechanism of a ratchet mechanism and a latching claw (the 1). The front view explaining the relationship between the ratchet mechanism of a ratchet wheel and a latching claw (the 2). Sectional drawing explaining an example of a structure of the conventional paper feeder.

Explanation of symbols

10 Paper Feeding Device 11 Stacking Plate (Stacking Plate for Feeding Tray)
11a Rotating shaft 12 Drive cam 13 Drive cam 14 Coil spring 15 Paper feed roller 16 Rolling base 17, 18 Transport roller 19 Drive gear 20 Clutch device 21 Planetary gear mechanism 21a Input shaft 21b Outer sun gear 21c Planetary gear 21d Inner sun gear 21e Carrier 21f Output Shaft 31 Ratchet mechanism 31a Claw wheel 31a1 First claw wheel 31a2 Second claw wheel 31b Locking claw device 31c Solenoid

Claims (5)

A clutch device of a paper feeding device that conveys a recording member to an image forming unit,
The clutch device includes an input shaft coupled to a power source, an output shaft coupled to a paper feed roller, a planetary gear mechanism disposed between the input shaft and the output shaft, and an output of the planetary gear mechanism Consists of a ratchet mechanism arranged on the shaft,
The ratchet mechanism includes a first claw wheel having a locking claw piece fixed on the output shaft, and a locking claw piece having a locking direction opposite to the locking claw piece of the first claw wheel. And a second claw wheel that frictionally contacts the first claw wheel, and a locking claw device that locks the locking claw piece of the first and second claw wheels. The clutch device of the paper feeding device. The sheet feeding device according to claim 1, wherein the second claw wheel is in frictional contact with the first claw wheel, and the second claw wheel is rotatable independently of the first claw wheel. Device clutch device. The locking claw device is set to a locking position and a locking release position on the locking claw pieces of the first and second claw wheels by a solenoid that operates in response to a paper feed command. Item 2. A clutch device for a sheet feeding device according to Item 1. The angular position θ2 with respect to the rotation axis of the adjacent claw piece adjacent to the second claw wheel is set smaller than the angular position θ1 with respect to the rotation axis of the adjacent claw piece adjacent to the first claw wheel. The clutch device for a paper feeding device according to any one of claims 1 to 3.   An image forming apparatus equipped with a paper feeding device comprising the clutch device according to claim 1.

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