JP2008002569A - Clutch device, sheet feeder and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To completely prevent colliding noises when finishing the energization of a solenoid while minimizing an increase in driving load and avoiding the influences of working environment and body life. <P>SOLUTION: This clutch device for intermittently transmitting rotating force to a feed roller comprises the solenoid 111 for moving a plunger 112 between a suction position and a release position with the suction of the plunger 112 or the suction release, and a control cam 183 having a lock portion 183a to be locked to the plunger 111, a first cam face 183b to be kept in the condition of not abutting on the plunger 111, and a second cam face 183c for pushing the plunger 111 to the side of the solenoid. When pushed into the control cam 183, the plunger 112 is held on the solenoid 111 using an abutting portion 114 on the solenoid 111 at the suction position, as a supporting point, so that an front end 112t and an end 112s on the opposite side are operated in a seesaw fashion. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image forming apparatus such as a copying machine, a printer, and a facsimile, and in particular, in a sheet feeding apparatus that feeds sheets one by one from a sheet stacking unit of the image forming apparatus, a rotational force is intermittently applied to a rotating body such as a feeding roller. The present invention relates to a clutch device that transmits automatically.

  2. Description of the Related Art Image forming apparatuses such as copying machines, printers, and facsimiles are provided with a sheet feeding device that separates sheets stacked on a sheet stacking unit one by one and feeds them to the image forming unit. This sheet feeding device has a clutch device for causing the feeding roller, to which the driving force is transmitted from the main body driving source through the gear, to perform an intermittent operation of one rotation. When the clutch device operates and the feeding roller starts to rotate, the cam attached to the shaft of the feeding roller also rotates, and the middle plate on which the sheets are stacked rises by the force of the spring. The sheet is pressed against the feeding roller by spring pressure. When the feeding roller rotates in a state where this pressure is applied, the sheets are fed from the stacked sheet bundle, separated one by one by the separation pad, and fed to the image forming apparatus main body.

  Here, the clutch device of the conventional sheet feeding device will be described with reference to FIGS. 18 is a perspective view of main parts of the clutch device, and FIG. 19 is a cross-sectional view of main parts of the clutch device.

  18 and 19, reference numeral 10 denotes a drive gear, which is always rotated counterclockwise by a motor and a gear train (not shown). The drive gear 10 has a plurality of teeth over the entire circumference.

  The shaft 9 of the feed roller is provided with a missing gear unit 8 having a missing tooth portion. The toothless gear unit 8 includes a drive toothless gear 81 that rotates integrally with the feed shaft 9, a control toothless gear 82 that is supported so as to be rotatable about a predetermined amount with respect to the drive toothless gear 81, and a unit. It is constituted by a toothless spring that gives the initial operating force of the control toothless gear internally. A control cam 83 provided with a locking portion is formed integrally with the control missing gear 82. The feed roller is provided so as to rotate integrally with the drive toothless gear 81 via the feed shaft 9.

  A plunger 12 is swingably supported by the solenoid 11. The plunger 12 is constantly urged in a direction to be pressed against the control cam 83 by a spring 13 as an urging means, and is attracted and moved in the opposite direction by a solenoid 11 at a predetermined timing, and is retracted from the locking portion 83a of the control cam 83. The

  In the clutch device configured as described above, when the plunger 12 is sucked and retracted and released from the engagement with the cam locking portion 83a based on the feed start signal, the control toothless gear 82 has its toothed portion caused by the toothless spring. It is engaged with the drive gear 10 and is driven to rotate by the drive gear 10. When the control toothless gear 82 rotates by a predetermined amount, the drive toothless gear 81 is rotated to the drive gear 10 side by the control toothless gear 82, is engaged with the drive gear 10, and is rotationally driven by the drive gear 10. When the driving toothless gear 81 is driven, the coaxial feeding roller 1 rotates and feeds a sheet such as a recording sheet on the intermediate plate.

  However, the clutch device shown in the conventional example has the following problems.

  Since the cam 83 is made of a rigid member such as hard resin, the plunger 12 collides with the outer periphery of the cam 83 when the plunger 12 is returned to the cam 83 side as shown in FIG. Impact sound is generated. When the feeding device having such a clutch device is continuously operated, the feeding operation is continuously performed, so that the above-described impact sound becomes very disturbing.

  Therefore, a technique for reducing the impact sound at the end of energization of the solenoid is disclosed. In this configuration, the height of the return surface of the cam surface is made higher than the suction position of the solenoid plunger, and the necessary overstroke of the plunger is absorbed by the cushioning material of the plunger abutting portion. Note that the plunger overstroke referred to here is the amount by which the plunger at the suction position is further pushed in by the cam in the suction direction. According to this configuration, when the solenoid is energized, the tip of the plunger is always in contact with the cam surface, so that the impact sound when returning the plunger is reduced (see, for example, Patent Document 1).

JP 11-190410 A

  However, in this configuration, it is necessary to set the crushing amount of the buffer material to be larger than that in the normal use in order to absorb the overstroke of the plunger. The shock-absorbing material varies depending on the material, the usage environment, and changes due to repeated loads. However, as described above, if the amount of crushing of the shock-absorbing material is increased, this variation increases. For this reason, if the amount of crushing of the cushioning material is increased, the suction position of the plunger by the solenoid is not stable due to the influence of the use environment and the life of the main body, and the feeding operation may become unstable. On the other hand, unless the amount of collapse of the cushioning material is increased, the overstroke cannot be absorbed, and the driving load increases at the contact portion between the plunger tip and the cam surface.

  Therefore, an object of the present invention can completely prevent an impact sound at the end of energization of the solenoid without being affected by the use environment and the life of the main body and minimizing an increase in driving load.

  A typical configuration of the present invention for achieving the above object is a clutch device that intermittently transmits a rotational force to a rotating body, which is attached coaxially to the rotating body and has a partially missing tooth portion. The toothless gear meshable with the drive gear, and the plunger is sucked or released by energization or termination of energization, so that the plunger is moved between the suction position where the suction is performed and the open position where the suction is released. A solenoid that is moved between, a locking portion that is locked to the plunger that is released from the suction, a first cam surface that is not in contact with the suctioned plunger, and the suctioned plunger. A second cam surface that contacts and pushes the plunger toward the solenoid, and a control cam that can rotate integrally with the toothless gear, and when the plunger is pushed into the control cam, Said Using the abutting portion with the solenoid in the pulling position as a fulcrum, the contact portion with the control cam and the end opposite to the contact portion are held by the solenoid so as to operate in a seesaw shape. It is characterized by that.

  According to the present invention, it is possible to completely prevent an impact sound at the end of energization of the solenoid without being influenced by the use environment and the life of the main body and minimizing an increase in driving load.

  Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, and relative arrangements of the components described in the following embodiments should be changed as appropriate according to the configuration of the apparatus to which the present invention is applied and various conditions. Therefore, unless specifically stated otherwise, the scope of the present invention is not intended to be limited thereto.

[First Embodiment]
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. Here, a sheet feeding apparatus provided with a clutch device will be described as an example.

  1 and 2 are cross-sectional views of the sheet feeding apparatus according to the first embodiment. FIG. 3 is a cross-sectional view of the sheet feeding device showing a clutch device that controls the rotation of the feeding roller. FIG. 4 is a perspective view showing the configuration of the clutch device, and FIG. 5 is an exploded perspective view showing the configuration of the missing gear unit in the clutch device. 6, 7 and 8 are sectional views showing the operation of the clutch device.

  First, the configuration of the sheet feeding device provided with the clutch device will be described. The sheet feeding device includes the following in addition to the clutch device described below.

  In FIG. 1, 1 is a feeding roller as a feeding rotating body, 2 is a feeding cam for controlling the vertical movement of the intermediate plate 4, 3 is a separation pad for separating sheets, and 4 is a leading end of a stacked sheet. An intermediate plate 5 that supports the side is an intermediate plate spring that applies a feeding pressure to the intermediate plate 4. Reference numeral 6 denotes a stacking tray on which sheets are stacked, and reference numeral 7 denotes a frame member that forms a sheet conveyance path.

  Although not shown here, the sheet feeding apparatus is provided in a printer as an image forming apparatus that forms an image on a sheet. That is, toner images are formed on the sheets fed one by one by the sheet feeding device in the image forming unit of the printer. Here, the electrophotographic image forming unit is exemplified as the image forming unit, but the image forming unit is not limited to this. For example, the image forming unit may be an ink jet type image forming unit that ejects ink to form an image. good.

  Next, the configuration of the clutch device in the sheet feeding device will be described. The clutch device in the sheet feeding device has the following.

  In FIG. 3, reference numeral 18 denotes a missing gear unit from which a part of the gear is removed in order to perform one rotation control of the feeding operation, and reference numeral 19 denotes a feeding unit that connects the missing gear unit, the feeding roller 1 and the feeding cam 2. This is the feed axis (angular axis). Reference numeral 20 denotes a driving gear for transmitting a driving force to the toothless gear unit, which is always rotated counterclockwise by a motor and a gear train (not shown). The drive gear 10 has a plurality of teeth over the entire circumference. A feeding solenoid 111 controls the start and stop of the feeding operation. 112 is a solenoid plunger which is attracted and operated by energization of the solenoid, and 113 is a solenoid spring which gives a return force to the solenoid plunger.

  In FIG. 4, reference numeral 181 denotes a drive toothless gear attached so as to rotate integrally with the feeding shaft 19. Reference numeral 182 denotes a control toothless gear attached to the drive toothless gear 181 so as to be capable of rotating at a constant angle. A missing tooth control cam 183 is integrally formed with the control missing gear 182 and controls the start and stop of the operation by the operation of the solenoid plunger 112. These gears 181, 182, cam 183, etc. constitute a missing gear unit 18.

  Reference numeral 111a denotes a plunger holder for holding the solenoid plunger 112 of the solenoid 111 in a rotatable manner. Reference numeral 114 denotes a front end side abutting portion of the plunger 112, which is formed of a sponge-like cushioning material. The cushioning material is formed with a foaming density that is almost completely crushed by the suction operation of the solenoid 111. The plunger holding portion 111a is formed in an arc shape centering on the tip of the plunger tip end abutting portion 114.

  As shown in FIG. 5, the drive partial gear 181 and the control partial gear 182 are configured such that the hole portion of the control partial gear 182 is rotatably fitted to the shaft portion of the drive partial gear 181. When the locking by the solenoid plunger 112 is released, the control missing gear 182 is rotated by the spring force of the missing tooth spring 184 as the initial rotation applying means.

  The rotation angle of the control toothless gear 182 with respect to the drive toothless gear 181 is set in the drive toothless gear 181 by the spring force from the standby position where the control toothless gear 182 is locked to the plunger 112. This is the rotation angle until it hits the stopper 181s. The rotation angle of the control toothless gear 182 with respect to the drive toothless gear 181 is set to be within a certain angle by the stopper 181s. The rotation angle of the control missing gear 182 within this fixed angle is such that when the control missing gear 182 hits the stopper 181s and the drive missing gear 181 rotates together, the gears 181 and 182 are integrated with each other. Thus, it is determined to be engaged with the drive gear 20. Here, when the control missing gear 182 is rotated by a predetermined angle (about 35 ° in this case) from the standby position locked to the solenoid plunger 112, it abuts against the stopper 181 s and is connected to the drive missing gear 181. It is the structure which rotates.

  When the control missing gear 182 becomes free by the operation of the feeding solenoid 111, first, the control missing gear 182 is rotated by the force of the spring 184 and is engaged with the drive gear 20. When the control toothless gear 182 rotates about 35 °, it hits the stopper 181 s and is connected to the drive toothless gear 181, and the drive toothless gear 181 is rotated from the standby position to the position where it can be engaged with the drive gear 20. The driving force is applied to the roller.

  On the other hand, the operation of the control missing gear 182 is stopped when the locking portion 183a of the missing tooth control cam 183 is caught by the plunger 112 of the feeding solenoid 111, and the drive missing gear 181 is on standby depending on the shape of the feeding cam 2. It stops at the position.

  The operation of this configuration will be described in detail below.

  When power is turned on from a main switch (not shown), a driving force is transmitted to a gear train (not shown) by a drive motor (not shown), and various rollers start to operate.

  Further, when a signal for starting the feeding operation is sent to the printer, the feeding roller 1 performs one rotation operation by the clutch device. When the feeding roller 1 rotates, the feeding cam 2 mounted coaxially with the feeding roller 1 also rotates in the same manner, and the holding mechanism for the middle plate 4 is released. Is rotated upward in the figure, and the state shown in FIG. 2 is obtained.

  The sheet set on the stacking tray 6 is pressed against the feeding roller 1 by the force of the spring 5 when the intermediate plate 4 is raised, and is fed from the stack of stacked sheets by the rotation of the feeding roller 1. Are separated and fed one by one.

  The fed sheet is sent to the image forming unit along the conveyance path to transfer the toner image, and the transferred toner image is fixed by the fixing unit.

  Further, after the feeding roller 1 rotates and the feeding roller 1 finishes the feeding operation, the feeding cam 2 abuts against the cam shape of the intermediate plate 4 and operates to push down the intermediate plate 4. After the intermediate plate 4 is pushed down by the feeding cam 2, the feeding roller 1 is configured to stop at the standby position.

  Further, the operation of the clutch device will be described in detail with reference to FIGS. 6, 7, and 8. FIG.

  FIG. 6 is a cross-sectional view showing a state in which the feeding solenoid 111 and the missing gear unit 18 are in the standby position. As shown in FIG. 6, the control toothless gear 182 is stopped at the standby position when the tip end portion 112 t of the solenoid plunger 112 is hooked on the locking portion 183 a of the control cam 183. The position of the plunger 112 shown in FIG. 6 is an open position where the suction is released by the end of energization of the solenoid.

  When the clutch device starts the feeding operation from the state shown in FIG. 6, it changes to the state shown in FIG. First, the solenoid plunger 112 is attracted by energizing the feeding solenoid 111 and is separated from the cam locking portion 183a of the control missing gear 182 (suction position). The control toothless gear 182 of the toothless gear unit 18 that is unlocked is rotated in the same direction as the rotation direction of the drive gear 20 by the spring force of the toothless spring 184 and is engaged with the drive gear 20.

  FIG. 7 shows a state in which the control missing gear 182 is rotated by about 35 °, from which the drive missing gear 181 is at a position where the rotational force is given by the control missing gear 182. In FIG. 7, Ron is a radius from the rotation center of the missing tooth control cam 183 to the tip position of the plunger 112 in the solenoid suction state. Ra is a radius of the first cam surface 183b from the rotation center of the missing tooth control cam 183 to the biting start portion where the control missing gear 182 is bitten by the drive gear 20. In the position shown in FIG. 7, the radius Ron to the tip position of the plunger 112 in the solenoid attracted state is set to be larger than the radius Ra to the biting start portion of the missing tooth control cam 183. That is, in the operation region in which the control missing gear 182 is rotated by the initial force of the spring 184, the tip of the solenoid plunger 112 and the missing tooth control cam 183 are in contact with each other so that no malfunction occurs.

  When the gear 182 further rotates from the state shown in FIG. 7, the state shown in FIG. 8 is obtained. In FIG. 8, Rb is the radius of the second cam surface 183 c after the control missing gear 182 is engaged with the drive gear 20 from the rotation center of the missing tooth control cam 183. The second cam surface 183c changes smoothly from the first cam surface 183b. The radius Rb of the second cam surface 183c of the missing tooth control cam 183 is set to be larger than the radius Ron to the tip position of the plunger 112 in the solenoid attracted state. That is, the missing tooth control cam 183 after the control missing gear 182 is engaged with the drive gear 20 pushes the solenoid plunger 112 in the suction state further to the solenoid side than the suction position shown in FIG.

  In the normal solenoid 111, if the cam shape is such that the tip of the plunger 112 is pushed in, the plunger 112 and the cam 183 are stretched and stacked. Therefore, here, the plunger holding portion 111a of the solenoid 111 has an arc shape centered on the tip of the plunger tip side abutting portion 114 so that the cam 183 rotates even when the tip of the plunger 112 is further pushed from the suction position. It is formed to become. In this manner, the plunger 112 has a tip direction 112t (cam locking side) and an end portion 112s (spring fixing side) opposite to the plunger 112, with the tip of the tip end abutting portion 114 serving as a fulcrum. It is possible to operate in the same direction as the seesaw. That is, when the distal end of the plunger 112 is further pushed into the solenoid side from the suction position by the second cam surface 183c of the cam 183, the spring fixing side of the plunger 112 has an arcuate plunger holding portion 111a with the distal end abutment portion 14 as a fulcrum. It works like a seesaw. As a result, even if the distal end of the plunger 112 is pushed further in the suction direction from the suction position, the overstroke of the plunger 112 can be absorbed by the seesaw-like operation described above.

  As shown in FIG. 8, energization of the solenoid 111 is terminated while the tip 112t (cam locking side) of the plunger 112 is completely in contact with the second cam surface 183c of the missing tooth control cam 183. The impact sound generated when the plunger 112 hits the cam 183 can be completely prevented. The timing for terminating energization of the solenoid 111 is calculated from the operation time by calculating the time when the tip of the solenoid plunger 112 is in the maximum radius region θm (region of radius Rb of the second cam surface 183c) of the control cam 183 in the figure. It comes to decide. That is, the second cam surface 183c of the control cam 183 is set in a plunger return position where the suction of the plunger 112 in the suction position is released, in a region where the toothless gear 182 is completely meshed with the drive gear 20. It is.

  Further, compared with an overstroke absorbing mechanism in which the cushioning material in the solenoid tip side abutting portion 114 is largely crushed, the feeding device has very little fluctuation due to the use environment and the number of operations. For this reason, it is possible to further stabilize the operation of the solenoid, and it is possible to completely prevent the impact sound generated when the tip of the plunger 112 hits the cam 183.

  FIG. 9 is a cross-sectional view showing the state of the feeding device when the clutch device is in the state shown in FIG. As shown in FIG. 9, the relationship between the feeding cam 2 and the intermediate plate 4 is such that the intermediate plate 4 biased by the spring 5 generates a force for rotating the feeding cam 2 in this state.

  Since the clutch device is configured to push the tip of the plunger 112 with the cam 183, the driving load increases in the region where the plunger 112 is pushed. However, when the clutch device is used simultaneously with the feeding device, the driving load is increased. It can be reduced by the rotational force on the middle plate 4 side. For this reason, it is not necessary to increase the output of the drive source due to an increase in the load of the clutch device.

  Further, as described above, since the feeding cam 2 is driven by the gear mechanism, the rotational speed does not change greatly even if the feeding force is received from the intermediate plate 4. Further, even if the feeding cam 2 and the intermediate plate 4 are in the relationship as shown in FIG. 9, the driving load is suddenly increased because the missing tooth control cam 183 and the plunger 112 generate a rotational load due to contact. However, the smoothness of the rotation of the gear train is not impaired. Furthermore, the noise accompanying the vertical movement of the intermediate plate 4 can be reduced.

  As described above, according to the present embodiment, it is possible to completely prevent an impact sound at the end of energization of the solenoid without being affected by the use environment and the life of the main body and minimizing an increase in driving load. it can.

[Second Embodiment]
Hereinafter, the second embodiment of the present invention will be described with reference to FIGS. Here, a sheet feeding apparatus provided with a clutch device will be described as an example. In the second embodiment, the configuration of the clutch device is changed from the first embodiment. In this description, the same members as those in the first embodiment described above are denoted by the same reference numerals.

  In FIG. 10, reference numeral 281 denotes a drive toothless gear attached so as to rotate integrally with the feeding shaft 19. A control missing gear 282 is attached to the drive missing gear 281 so as to be rotatable at a constant angle. 283 is a missing tooth control cam that is integrally formed with the control missing tooth gear 282 and controls the start and stop of the operation by the operation of the solenoid plunger 212. These gears 281 and 282, the cam 283, and the like constitute a missing gear unit 28.

  Further, 211 is a solenoid, 212 is a solenoid plunger, 211a is a plunger holding portion for rotatably holding the solenoid plunger 212 of the solenoid 211, and 213 is a solenoid spring that gives a return force to the solenoid plunger 212. Reference numeral 214 denotes a plunger-side abutting portion, which is formed of a sponge-like cushioning material. The cushioning material is formed with a foaming density that is almost completely crushed by the suction force of the solenoid 211.

  Reference numeral 20 denotes a drive gear that applies a driving force to the partial gear unit, and reference numeral 19 denotes a feed shaft that connects the drive partial gear, the feed roller, and the feed cam.

  As shown in FIG. 11, the drive partial gear 281 and the control partial gear 282 are configured such that the hole portion of the control partial gear 282 is rotatably fitted to the shaft portion of the drive partial gear 281. When the locking by the solenoid plunger 212 is released, the control missing gear 282 is rotated by the spring force of the missing tooth spring 284 as the initial rotation applying means.

  The rotation angle of the control toothless gear 282 relative to the drive toothless gear 281 is set in the drive toothless gear 281 by a spring force from the standby position where the control toothless gear 282 is locked to the plunger 212. The rotation angle until it hits the stopper 281s. The rotation angle of the control toothless gear 282 with respect to the drive toothless gear 281 is set to be within a certain angle by the stopper 281s. The rotation angle of the control missing gear 282 within this fixed angle is such that when the control missing gear 282 hits the stopper 281s and the driving missing gear 281 rotates together, the gears 281 and 282 are integrated with each other. Thus, it is determined to be engaged with the drive gear 20. Here, when the control missing gear 282 is rotated by a predetermined angle (about 35 ° in this case) from the standby position locked to the solenoid plunger 212, it abuts against the stopper 281 s and is connected to the driving missing gear 281. It is the structure which rotates.

  When the control missing gear 282 becomes free by the operation of the feeding solenoid 211, first, the control missing gear 282 is rotated by the force of the spring 284 and is engaged with the drive gear 20. When the control toothless gear 282 rotates about 35 °, it hits the stopper 281s and is connected to the drive toothless gear 281. The drive toothless gear 281 is rotated from the standby position to the position where it can be engaged with the drive gear 20, and fed. The driving force is applied to the roller.

  On the other hand, the operation of the control missing gear 282 is stopped by the engaging portion 283a of the missing tooth control cam 283 being caught by the plunger 212 of the feeding solenoid 211, and the drive missing gear 281 is on standby depending on the shape of the feeding cam 2. It stops at the position.

  A control cam 283 formed integrally with the control toothless gear 282 has a second cam surface 283c, which will be described later, divided into a large radius portion Rb2 and a small radius portion Rs2 in the axial direction as shown in FIG. It has a shape.

  Further, as shown in FIG. 13, the solenoid plunger 212 is offset from the center of the suction operation direction so that the tip end portion 212 t that locks the control toothless gear 282 is located outside the solenoid tip end abutting portion 214. It is configured.

  Hereinafter, the operation of the clutch device will be described in detail with reference to FIGS.

  FIG. 14 is a cross-sectional view showing a state where the feeding solenoid 211 and the missing tooth unit 28 are in the standby position. As shown in FIG. 14, the control toothless gear 282 is stopped at the standby position when the tip end portion 212 t of the solenoid plunger 212 is caught by the locking portion 283 a of the control cam 283. The position of the plunger 212 shown in FIG. 14 is an open position where the suction is released by the end of energization of the solenoid.

  When the clutch device starts the feeding operation from the state shown in FIG. 14, it changes to the state shown in FIG. First, the solenoid plunger 212 of the feeding solenoid 211 is attracted by being energized to the solenoid 211 and is separated from the cam locking portion 283a of the control missing gear 282 (suction position). The control toothless gear 282 of the toothless gear unit 28 rotates in the same direction as the rotation direction of the drive gear 20 by the spring force of the toothless spring 284 and is engaged with the drive gear 20.

  FIG. 15 shows a state in which the control missing tooth gear 282 is rotated by about 35 °, from which the drive missing tooth gear 281 is in a position where rotational force can be given by the control missing tooth 282. In FIG. 15, Ron2 is a radius from the rotation center of the missing tooth control cam 283 to the tip position of the plunger 212 in the solenoid suction state. Ra2 is the radius of the first cam surface 283b from the rotation center of the missing tooth control cam 283 to the biting start portion where the control missing gear 282 is bitten by the drive gear 20. In the position shown in FIG. 15, the radius Ron2 to the tip position of the plunger 212 in the solenoid suction state is set to be larger than the radius Ra2 to the biting start portion of the missing tooth control cam 283. That is, in the operation region in which the control missing tooth gear 282 is rotated by the initial force of the spring 284, the tip of the solenoid plunger 212 and the missing tooth control cam 283 are in contact with each other so that no malfunction occurs.

  When the gear 282 further rotates from the state shown in FIG. 15, the state shown in FIG. 16 is obtained. In FIG. 16, Rb <b> 2 is a radius (large radius portion) of the second cam surface 283 c after the control missing gear 282 is engaged with the drive gear 10 from the rotation center of the missing tooth control cam 283. In the position shown in FIG. 16, the radius Rb2 of the second cam surface 283c of the missing tooth control cam 283 is set to be larger than the radius Ron2 to the tip position of the plunger 212 in the solenoid attracted state. That is, the missing tooth control cam 283 after the control missing gear 282 is engaged with the drive gear 20 is configured to push the solenoid plunger 212 in the suction state further to the solenoid side than the suction position shown in FIG.

  If the normal solenoid 211 has a cam shape that pushes the tip of the plunger 212, the plunger 212 and the cam 283 are stretched and stacked. Therefore, here, the cam 283 of the control toothless gear 282 has a stepped shape (large radius portion Rb2 and small radius portion Rs2) having a larger radius toward the axial gear as shown in FIG. In addition, the tip end portion 212t of the plunger 212 of the solenoid 211 is located outside the region of the tip end abutting portion 214 (close to the gear) so as to correspond to the large radius portion Rb2 as the second cam surface 283c of the cam 283. It has an offset shape. For this reason, the plunger 212 has a tip 212t (cam locking side) and an end 212s (butting portion outside) on the opposite side as a fulcrum on the tip side butting portion 214 inside (gear side). It is possible to operate in a seesaw shape in a direction crossing the suction direction. As a result, even if the large radius portion Rb2 of the cam 283 pushes the distal end portion 212t of the plunger 212 further than the suction position, the overstroke of the plunger 212 can be absorbed by the aforementioned seesaw-like operation.

  As shown in FIG. 16, the energization of the solenoid 211 is terminated while the tip end 212t (cam locking side) of the plunger 212 is completely in contact with the second cam surface 283c of the missing tooth control cam 283. The impact sound generated when the plunger 212 hits the cam 283 can be completely prevented. The timing for ending energization of the solenoid 211 is calculated from the operation time by calculating the time when the tip of the solenoid plunger 212 is in the maximum radius region θb2 (region of the radius Rb2 of the second cam surface 283c) of the control cam 283 in the figure. It comes to decide. That is, the second cam surface 283c of the control cam 283 is set in the plunger return position where the suction of the plunger 212 in the suction position is released, within the region where the toothless gear 282 is completely meshed with the drive gear 20. It is.

  Further, compared to an overstroke absorbing mechanism in which the cushioning material at the solenoid tip side abutting portion 214 is largely crushed, the feeding device has very little fluctuation due to the use environment and the number of operations. For this reason, it is possible to further stabilize the operation of the solenoid, and it is possible to completely prevent the impact sound generated when the tip end 212t of the plunger 212 hits the cam 283.

  Further, as compared with the configuration of the first embodiment, the operation amount of the solenoid spring 213 during the overstroke operation of the solenoid plunger 212 can be reduced. For this reason, not only the same effects as the above-described embodiment can be obtained, but also the load increase amount when the solenoid plunger 212 is pushed in can be reduced, and the load balance with the feeding device can be more appropriate. .

  As described above, also in this embodiment, it is possible to completely prevent an impact sound at the end of energization of the solenoid without being affected by the use environment and the life of the main body and minimizing an increase in driving load. .

[Other Embodiments]
In the above-described embodiment, the sheet feeding apparatus that feeds a sheet such as a recording sheet as a recording target is exemplified, but the present invention is not limited to this. For example, the same effect can be obtained even when the present invention is applied to a sheet feeding apparatus that feeds a sheet such as a document to be read.

  In the above-described embodiment, the printer is exemplified as the image forming apparatus, but the present invention is not limited to this. For example, the image forming apparatus may be another image forming apparatus such as a scanner, a copier, or a facsimile machine, or another image forming apparatus such as a multifunction machine that combines these functions. The same effect can be obtained by applying the present invention to a sheet feeding apparatus used in these image forming apparatuses.

  The sheet feeding apparatus having the clutch device may be configured to be detachable from the image forming apparatus, or may be configured to be integrated with the image forming apparatus. The same effect can be obtained by applying the present invention to the clutch device of such a sheet feeding device.

Cross section of sheet feeding device Cross section of sheet feeding device Sectional view of sheet feeding device showing clutch device for controlling rotation of feeding roller The perspective view which shows the structure of the clutch apparatus which concerns on 1st Embodiment. The disassembled perspective view which shows the structure of the missing-tooth gear unit in the clutch apparatus which concerns on 1st Embodiment. Sectional drawing which shows operation | movement (cam locking state) of the clutch apparatus which concerns on 1st Embodiment. Sectional drawing which shows operation | movement (cam lock release state) of the clutch apparatus which concerns on 1st Embodiment. Sectional drawing which shows operation | movement (plunger pushing state) of the clutch apparatus which concerns on 1st Embodiment. Sectional drawing which shows the state of the sheet feeding apparatus when the clutch apparatus which concerns on 1st Embodiment is in the state shown in FIG. The perspective view which shows the structure of the clutch apparatus which concerns on 2nd Embodiment. The disassembled perspective view which shows the structure of the missing-tooth gear unit in the clutch apparatus which concerns on 2nd Embodiment. The perspective view which shows the structure of the missing-tooth gear unit in the clutch apparatus which concerns on 2nd Embodiment. The perspective view which shows the structure of the solenoid plunger part in the clutch apparatus which concerns on 2nd Embodiment. Sectional drawing which shows operation | movement (cam locking state) of the clutch apparatus which concerns on 2nd Embodiment. Sectional drawing which shows operation | movement (cam lock release state) of the clutch apparatus which concerns on 2nd Embodiment. Sectional drawing which shows operation | movement (plunger pushing state) of the clutch apparatus which concerns on 2nd Embodiment. The perspective view which shows the plunger pushing-in state of the clutch apparatus which concerns on 2nd Embodiment. The perspective view which shows the structure of the conventional clutch apparatus. Sectional drawing which shows the structure of the conventional clutch apparatus

Explanation of symbols

Ra, Ra2 ... Radius Rb, Rb2 of the first cam surface ... Radius Ron, Ron2 of the second cam surface ... Radius θm, θb2 to the tip of the plunger ... Maximum radius region 1 ... Feed roller (feed rotator)
2 ... Feeding cam 3 ... Separation pad 4 ... Intermediate plate 5 ... Intermediate leaf spring 6 ... Loading tray 7 ... Frame members 18, 28 ... Missing gear unit 19 ... Feed shaft 20 ... Drive gears 111, 211 ... Solenoid 111a ... Plunger holding portion 112, 212 ... Solenoid plunger 112s, 212s ... End portion 112t, 212t ... End portion 113, 213 ... Solenoid spring 114, 214 ... End side abutting portion 181, 281 ... Drive missing gear 181s, 281s ... Stopper 182 , 282 ... Control missing tooth gears 183 and 283 ... Missing tooth control cams 183a and 283a ... Locking portions 183b and 283b ... First cam faces 183c and 283c ... Second cam faces 184 and 284 ... Missing tooth spring (initial rotation) Granting means)

Claims (8)

A clutch device that intermittently transmits rotational force to a rotating body,
A non-tooth gear that is mounted coaxially with the rotating body, has a partially-toothed portion, and can mesh with a drive gear;
A solenoid for moving the plunger between the sucked suction position and the open position where the suction is released by sucking or releasing the plunger by energization or energization; and
An engaging portion that is engaged with the plunger that is released from the suction, a first cam surface that maintains a non-contact state with the attracted plunger, and the plunger that is in contact with the attracted plunger A second cam surface to be pushed into, and a control cam rotatable integrally with the toothless gear,
When the plunger is pushed into the control cam, the abutting portion with the solenoid at the suction position serves as a fulcrum, and the abutting portion with the control cam and the end opposite to the abutting portion Is held by the solenoid so as to operate like a seesaw.   2. The clutch device according to claim 1, wherein the plunger is held by the solenoid so as to operate in a seesaw shape in the same direction as a suction direction of the plunger with the abutting portion as a fulcrum. .   2. The clutch according to claim 1, wherein the plunger is held by the solenoid so as to operate in a seesaw shape in a direction intersecting the suction direction of the plunger with the abutting portion as a fulcrum. apparatus.   The clutch according to any one of claims 1 to 3, wherein the second cam surface of the control cam is set to a plunger return position where the suction of the plunger at the suction position is released. apparatus. A feeding rotating body for feeding the sheet;
An intermediate plate on which sheets are stacked and supported so as to be movable up and down;
A feeding cam that is mounted coaxially with the feeding rotating body and that moves the middle plate up and down by rotation;
A sheet feeding device having a clutch device that intermittently transmits a rotational force to the feeding rotating body,
A sheet feeding device comprising the clutch device according to claim 1 as the clutch device.   The second cam surface of the control cam is set in a plunger return position in a region where the toothless gear is completely meshed with the drive gear and the suction of the plunger in the suction position is released. The sheet feeding apparatus according to claim 5.   The second cam surface of the control cam is in a region where the feeding cam receives a rotational force in the sheet feeding direction from the middle plate, and is set to a plunger return position where the suction of the plunger at the suction position is released. The sheet feeding device according to claim 5, wherein the sheet feeding device is provided.   8. An image forming apparatus comprising: the sheet feeding device according to claim 5; and an image forming unit that forms an image on a sheet fed by the sheet feeding device. .

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