JP4860384B2 - Clutch device and image forming apparatus equipped with the same - Google Patents

Description

  The present invention relates to a clutch device that intermittently transmits power between a driving shaft and a driven shaft. The present invention also relates to an image forming apparatus equipped with this clutch device.

  The clutch device is used to intermittently transmit power between the driving shaft and the driven shaft. In an image forming apparatus such as a copying machine or a printer, the clutch device is used for transmitting power to a paper feeding roller, a registration roller, a developing roller, and the like. In an image forming apparatus, it is necessary to drive a large number of rotating bodies such as paper feed rollers with as few motors as possible. Therefore, since a large number of rollers are connected to one motor, it is necessary to selectively transmit power to each of the rollers. For this reason, a clutch device is used between the motor and each roller.

  The clutch device includes a mechanism in which two members are in contact with each other like a friction clutch, and a mechanism such as a fluid clutch using a fluid. A mechanism using a clutch element composed of a clamping spring or a ring that can be expanded / contracted is one in which two members are in contact with each other. In this method, the shaft disposed inside the spring is tightened and contracted by contracting the tightening spring to transmit power, and the shaft is released by expanding the ring to interrupt power transmission.

  In the clutch mechanism using the clamping spring as described above, expansion / contraction of the clamping spring is performed by rotation control of the clamping spring. For example, when the tightening spring is always contracted and the shaft is tightened, the rotation of the tightening spring is stopped, so that the frictional force from the shaft acts on the tightening spring in the expansion direction to release the shaft. To do.

  The rotation control of the clamping spring is performed by an intermittent mechanism including a sleeve connected to the clamping spring and a claw that engages with the sleeve. The sleeve has teeth, and when the claw is put on the teeth, the rotation of the sleeve can be stopped and the rotation of the clamping spring can be stopped at the same time.

An example of a clutch mechanism using a clutch element composed of a clamping spring as described above can be seen in Patent Document 1. In the sheet feeding device of the image forming apparatus described in Patent Document 1, in order to separate and send out sheets (paper) one by one, as a spring clutch used when intermittently applying a sheet feeding pressure to the sheet, A clutch mechanism is applied.
JP-A-8-295424 (page 4, FIG. 4)

  Here, in a spring clutch (clutch mechanism) applied to the sheet supply device of the image forming apparatus described in Patent Document 1, a roller connected to a driven shaft and rotated at a timing that does not require rotation is rotated as long as possible. Consider stopping and extending the life of the roller. Therefore, from the state where the rotation of the driving shaft is stopped, the transmission of power from the driving shaft to the driven shaft is interrupted simultaneously with the start of rotation of the driving shaft, that is, only the driving shaft is rotated. In this case, it is possible to rotate only the driving shaft simultaneously with the start of rotation of the driving shaft by operating the intermittent mechanism in a state where the rotation of the driving shaft is stopped and stopping the rotation of the clamping spring (clutch element). It is thought that there is.

  However, in the spring clutch, as described above, the tightening spring stops the rotation of the tightening spring when it is contracted and the shaft is tightened, so that the frictional force from the shaft acts in the extending direction of the tightening spring. Release the shaft. Therefore, even if the rotation of the clamping spring is stopped by the intermittent mechanism at the same time as the rotation of the driving shaft, unlike the case where the rotation of the clamping spring in the rotating state is stopped, the expansion of the clamping spring is insufficient. , Can not open the shaft. As a result, a halfway frictional force is generated between the clamping spring and the shaft to which the spring is tightened, and the clutch spring is damaged during this time, and the clutch mechanism is damaged. There is a risk of doing.

  The present invention has been made in view of the above points, and stops the clutch element that generates a coupling action when the driving shaft rotates in a specific direction and the clutch element that rotates together with the driving shaft in the specific direction. In a clutch device equipped with a clutch mechanism that is provided with an intermittent mechanism that cuts off power transmission to the shaft, it is possible to prevent problems such as wear of the clutch element and the shaft and generation of frictional heat between the two. On the other hand, to provide a clutch device capable of rotating only the driving shaft as early as possible after starting the rotation of the driving shaft, and capable of stopping the rotation of a roller at a timing not requiring rotation as long as possible. Objective. It is another object of the present invention to provide an image forming apparatus having a long life by mounting this clutch device.

  In order to solve the above-described problems, the present invention has a driving shaft and a driven shaft aligned on a common axis, and is interposed between both the shafts, and a coupling action occurs when the driving shaft rotates in a specific direction. A clutch mechanism provided with a clutch element and an interrupting mechanism for stopping power transmission from the driving shaft to the driven shaft by stopping the clutch element rotating together with the driving shaft in the specific direction, and controlling the operation of the interrupting mechanism. In the clutch device including the control unit, the control unit causes the intermittent mechanism to act after at least one rotation of the clutch element after starting the rotation of the driving shaft, and transmits power from the driving shaft to the driven shaft. It was decided to shut off.

  In the present invention, the clutch device is mounted on the image forming apparatus.

  According to the configuration of the present invention, the clutch element that generates a coupling action when the driving shaft rotates in a specific direction, and the clutch element that rotates together with the driving shaft in the specific direction are stopped to transmit power from the driving shaft to the driven shaft. In the clutch device including the clutch mechanism provided with the interrupting mechanism for shutting off, the control unit operates the interrupting mechanism after the clutch element has made at least one rotation after the start of the rotation of the driving shaft, and from the driving shaft to the driven shaft. Therefore, it is possible to obtain a sufficient frictional force from the shaft to expand the clutch element by applying a rotational force to the clutch element before the intermittent mechanism is operated. As a result, only the driving shaft can be rotated at the earliest possible stage after starting the rotation of the driving shaft, while preventing problems such as wear of the clutch element and the shaft and generation of frictional heat between them. Can do. Accordingly, it is possible to obtain a high-performance clutch device capable of stopping rotation of a roller at a timing that does not require rotation for as long as possible and capable of extending the life of such a roller.

  In the present invention, since the clutch device is mounted on the image forming apparatus, it is possible to prevent a problem that the clutch element and the shaft are worn or a frictional heat is generated between them. An image forming apparatus with a long service life that can rotate only the driving shaft at the earliest possible stage after the shaft starts rotating and can stop the rotation of the roller at a timing that does not require rotation for as long as possible. Obtainable.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. In the image forming apparatus, the clutch device according to this embodiment is provided for a roller such as a paper feeding roller, a conveying roller, a registration roller, or a developing roller used for image formation that is rotated to convey a sheet. It shall be installed to be used.

  First, an image output operation of an image forming apparatus equipped with the clutch device of the present invention will be described with reference to FIG. FIG. 1 is a schematic vertical sectional left side view showing an image forming apparatus equipped with a clutch device according to an embodiment of the present invention. In FIG. 1, the right side is the front side of the image forming apparatus, and the left side is the back side.

  As shown in FIG. 1, a sheet supply device 20 is disposed below the main body 2 of the image forming apparatus 1. The paper supply device 20 is provided with a paper cassette 21 that is a paper storage unit, in which paper P such as cut paper before printing is stacked and stored. A paper feed roller 22 is disposed on the downstream side of the paper cassette 21 in the paper conveyance direction, that is, on the upper right side in FIG. The paper feed roller 22 separates and feeds the paper P one by one toward the upper right of the paper cassette 21 in FIG.

  A paper transport path 3, a registration roller 4, an image forming unit 30, and a transfer unit 40 are disposed downstream of the paper cassette 21 in the paper transport direction. The paper P sent out from the paper cassette 21 reaches the registration roller 4 through the paper transport path 3. The registration roller 4 corrects the oblique feeding of the paper P, measures the timing with the toner image formed by the image forming unit 30, and sends the paper P to the transfer unit 40.

  On the other hand, image data signals such as characters, graphics, and patterns from an external computer (not shown) are transmitted to the image forming apparatus 1, and based on this image data, the optical unit 5 provided above the image forming unit 30. Laser light L to be controlled (dotted line in the figure) is irradiated. As a result, in the image forming unit 30, an electrostatic latent image of the original image is formed on the photosensitive drum 31 that is an image carrier. From this electrostatic latent image, a toner image is developed by a developing roller 32 disposed facing the photosensitive drum 31. The toner image is transferred to the paper P sent in synchronization by the registration roller 4 at a transfer nip portion formed by press contact between the photosensitive drum 31 and the transfer roller 41 of the transfer portion 40.

  A fixing device 6, a paper transport path 7, and a paper discharge unit 8 are disposed downstream of the image forming unit 30 and the transfer unit 40 in the paper transport direction. The sheet P carrying the unfixed toner image in the transfer unit 40 is sent to the fixing device 6 and the toner image is fixed by the heat roller and the pressure roller. The paper P discharged from the fixing device 6 is sent upward through the paper transport path 7 and discharged from the paper discharge port 9 to a paper discharge portion 8 which is a paper placement portion provided at the top of the main body 2. Is done.

  In the image forming apparatus 1 having the above-described configuration, the clutch device of the present invention is, as described above, the paper feed roller 22 or the transport roller rotated to transport the paper P, the registration roller 4, or the development used for image formation. This is used for a roller such as the roller 32, and here, what is provided in the developing roller 32 of the image forming unit 30 will be described below.

  A detailed configuration of the clutch device according to the embodiment of the present invention will be described with reference to FIGS. 2 and 3 in addition to FIG. 2 is a perspective view of the periphery of the clutch device, and FIG. 3 is a vertical sectional side view of the clutch mechanism of the clutch device shown in FIG.

  A clutch device 50 shown in FIG. 2 is provided at the shaft end of the developing roller 32 shown in FIG. In addition to the developing roller 32, a plurality of rollers (not shown) are connected to the motor 10 provided in the image forming apparatus 1 through gears. However, the developing roller 32 does not always rotate and execute development, but needs to selectively transmit power at a predetermined timing to rotate. For this reason, transmission of power from the motor 10 is interrupted by the clutch device 50.

  As shown in FIGS. 2 and 3, the clutch device 50 includes a clutch gear 60 provided with a driving gear 61 corresponding to a driving shaft, a driven shaft 62, a clamping spring 63 that is a clutch element, and an interrupting mechanism 70. , And a control unit 90 that controls the operation of the interrupting mechanism 70.

  The driving gear 61 is rotated by the motor 10 shown in FIG. As shown in FIG. 3, the driving gear 61 has a shaft portion 62 a of the driven shaft 62 and a support shaft 32 a of the developing roller 32 so that the axis thereof, that is, the axis of the driving shaft and the axis of the driven shaft 62 coincide with each other. Accept. As a result, the driving gear 61 and the driven shaft 62 corresponding to the driving shaft are aligned on the common axis. The support shaft 32 a of the developing roller 32 is inserted and fixed in a center hole provided along the axis of the driven shaft 62. The driving gear 61 and the driven shaft 62 can rotate independently. An intermediate gear may be disposed between the motor 10 and the driving gear 61.

  The clamping spring 63 is constituted by a coil spring and is disposed inside the sleeve 71 of the interrupting mechanism 70. The clamping spring 63 is provided so that the axis thereof coincides with the axis of the driving gear 61 and the driven shaft 62, and the boss portion 61a of the driving gear 61 and the shaft portion 62a of the driven shaft 62 are passed through the inside of the coil. Yes.

  One end of the clamping spring 63 is attached to the shaft portion 62a of the driven shaft 62 and the other end is attached to the sleeve 71 so as not to rotate. These attachment portions are fixed to the shaft portion 62a and the sleeve 71 in such a manner that the end portion of the coil wire is bent at 90 °. The driving gear 61 is disposed at the end of the tightening spring 63 on the side where the sleeve 71 is attached, and the boss 61a of the driving gear 61 is inserted from the end of the tightening spring 63 into the coil. The outer diameter of the boss portion 61 a of the driving gear 61 is a value close to the inner diameter of the coil of the tightening spring 63, and the boss portion 61 a of the driving gear 61 is connected to the tightening spring 63 when the intermittent mechanism 70 is not operating. Lightly touching. In this way, the clamping spring 63 is interposed between the driving gear 61 corresponding to the driving shaft and the driven shaft 62.

  The intermittent mechanism 70 includes a sleeve 71, teeth 72, claws 73, and a solenoid 80.

  The sleeve 71 is adjacent to the driving gear 61 and is rotatably disposed outside the boss portion 61 a of the driving gear 61 and the shaft portion 62 a of the driven shaft 62. As described above, the clamping spring 63 is provided inside the sleeve 71 and between the boss portion 61a and the shaft portion 62a, and one end of the clamping spring 63 is fixed to the inner surface of the sleeve 71.

  The teeth 72 are provided on the outer peripheral surface of the sleeve 71 as shown in FIGS. Four teeth 72 are provided in the circumferential direction of the sleeve 71. The tooth 72 has a sawtooth cross-sectional shape in a direction perpendicular to the axial direction of the sleeve 71, and one end surface in the circumferential direction of the sleeve 71 is parallel to the diameter line of the sleeve 71. Note that the number of teeth 72 is not limited to four, and may be any other number.

  As shown in FIG. 2, the solenoid 80 is a flapper type, and includes a solenoid flapper 81, an electromagnet 82, and a spring 83.

  The solenoid flapper 81 is a flat plate-like member extending in a direction perpendicular to the sleeve axial direction. One end of the solenoid flapper 81 is bent at approximately 90 °, and the tip is configured as a claw 73. As shown in FIG. 2, the claw 73 is located in the vicinity of the sleeve 71 and outside the sleeve 71 in the radial direction. The solenoid flapper 81 is made of a magnetic metal and operates like a seesaw around the support portion 81a by the action of the electromagnet 82 and the spring 83. When the solenoid flapper 81 rotates counterclockwise in FIG. 2, the claw 73 engages with the end surface of the tooth 72 of the sleeve 71 parallel to the diameter line of the sleeve 71 and stops the rotation of the sleeve 71. The claw 73 is arranged so that the center of the claw 73 in the sleeve axial direction coincides with the center of the tooth 72 in the sleeve axial direction.

  The electromagnet 82 is provided on the sleeve 71 side in the vicinity of the support portion 81a of the solenoid flapper 81, that is, below the solenoid flapper 81 in FIG. One end of the spring 83 is connected to the end 81b of the solenoid flapper 81 opposite to the claw 73 with the rotation center 81a therebetween. The other end of the spring 83 is connected to the base portion 84 of the solenoid 80, and the spring 83 biases the solenoid flapper 81 in the clockwise direction in FIG. 2, that is, the direction away from the electromagnet 82. The solenoid flapper 81 rotates on a plane perpendicular to the axis of the sleeve 71 by turning on / off the power supply of the solenoid 80. In the power-on state, the solenoid flapper 81 is attracted and displaced by the electromagnet 82, and the claw 73 is engaged with the teeth 72 of the sleeve 71. When the power is OFF, the solenoid flapper 81 is separated from the electromagnet 82 by the action of the spring 83, the claw 73 side of the solenoid flapper 81 is displaced upward, and the engagement between the claw 73 and the teeth 72 is released.

  In the intermittent mechanism 70 configured as described above, the operation of the solenoid 80 is controlled by the control unit 90 shown in FIG. The control unit 90 may be configured as a part of a control device (not shown) that controls the entire image forming apparatus 1.

  Next, the power transmission operation by the clutch device 50 will be described with reference to FIGS. 4 and 5 in addition to FIGS. 2 and 3. 4 is a vertical sectional side view of the same clutch mechanism as in FIG. 3, showing a state in which the connection between the driving gear and the driven shaft is released, and FIG. 5 is a control chart showing the operation of the clutch device.

  In the clutch device 50, when the control unit 90 turns off the solenoid 80 of the interrupting mechanism 70, the claw 73 side of the solenoid flapper 81 is displaced upward as shown in FIG. Is disengaged. The sleeve 71 is allowed to rotate following the driving gear 61 without being restrained by the claw 73, and the clamping spring 63 is wound around the boss portion 61a of the driving gear 61 as shown in FIG. As a result, a coupling action is generated by the clamping spring 63 between the driving gear 61 and the driven shaft 62. Therefore, when the driving gear 61 is rotated by the motor 10, this power is transmitted to the driven shaft 62, and the developing roller 32 (see FIG. 1) is rotated.

  Next, when the controller 90 turns on the solenoid 80, the solenoid flapper 81 is attracted and displaced by the electromagnet 82, and the claw 73 is engaged with the teeth 72 of the sleeve 71. When the claw 73 is engaged with the tooth 72, the sleeve 71 is braked and stops rotating. At the same time, the rotation of the clamping spring 63 having one end attached to the sleeve 71 and the driven shaft 62 to which the other end of the clamping spring 63 is attached is also stopped. At this time, since the driving gear 61 is still rotating, the tightening spring 63 is twisted in the expansion direction due to friction between the boss portion 61 a of the driving gear 61 and the tightening spring 63. As a result, the tightening of the tightening spring 63 at the boss portion 61a of the driving gear 61 becomes loose, the boss portion 61a of the driving gear 61 slips inside the coil of the tightening spring 63, and the connection between the driving gear 61 and the tightening spring 63 is released. Is done. Therefore, even if the driving gear 61 is rotated by the motor 10, this power is not transmitted to the developing roller 32.

  In the clutch device 50 that performs the power transmission operation as described above, when there is no need to rotate the developing roller 32 at the start of rotation of the motor 10, that is, the driving gear 61, the control is performed as shown in the chart of FIG.

  According to FIG. 5, after the motor 10 is powered on and the driving gear 61 starts to rotate, the control unit 90 turns the solenoid 80 in a power-off state until the tightening spring 63 rotates at least once. As a result, the clamping spring 63 is wound around the boss portion 61 a of the driving gear 61, and a coupling action by the clamping spring 63 occurs between the driving gear 61 and the driven shaft 62. When the clamping spring 63 rotates once, the control unit 90 turns on the solenoid 80 to cause the clamping spring 63 to be sufficiently twisted in the extending direction. As a result, the boss portion 61a of the driving gear 61 slides inside the coil of the clamping spring 63, and the coupling between the driving gear 61 and the clamping spring 63 is released. Note that the timing at which the tightening spring 63 rotates once, which is controlled by the control unit 90, is set based on the time measured in advance.

  In this way, the clamping spring 63 that is a clutch element that generates a coupling action when the driving gear 61 corresponding to the driving shaft rotates in a specific direction, and the clamping spring 63 that rotates together with the driving gear 61 in the specific direction are stopped. In the clutch device 50 including the clutch mechanism 60 provided with the intermittent mechanism 70 that interrupts the power transmission from the driving gear 61 to the driven shaft 62, the control unit 90 allows the tightening spring 63 to move after the driving gear 61 starts rotating. After at least one rotation, the intermittence mechanism 70 is actuated to cut off power transmission from the driving gear 61 to the driven shaft 62. Therefore, before the intermittence mechanism 70 is actuated, a rotational force is applied to the clamping spring 63 to It is possible to obtain a sufficient frictional force from the boss portion 61a of the driving gear 61 to expand the torque. Thus, the driving gear 61 is prevented as early as possible after the starting of the rotation of the driving gear 61 while preventing the trouble that the tightening spring 63 and the boss portion 61a are worn or the frictional heat is generated between them. Can only be rotated. Therefore, it is possible to obtain a high-performance clutch device 50 that can stop the rotation of the developing roller 32 at a timing that does not require rotation as long as possible, and can extend the life of the developing roller 32.

  In the present invention, since the clutch device 50 is mounted on the image forming apparatus 1, it is possible to prevent a problem that the tightening spring 63 and the boss portion 61 a are worn or a frictional heat is generated between them. Since the driving gear 61 can be rotated as early as possible, only the driving gear 61 can be rotated at the earliest possible stage so that the developing roller 32 at a timing that does not require rotation can be stopped for as long as possible. The obtained image forming apparatus 1 can be obtained.

  Although the embodiments of the present invention have been described above, the scope of the present invention is not limited to these embodiments, and various modifications can be made without departing from the spirit of the invention.

  The present invention relates to a clutch element that generates a coupling action when the driving shaft rotates in a specific direction, and an intermittent mechanism that stops the clutch element that rotates together with the driving shaft in the specific direction and interrupts power transmission from the driving shaft to the driven shaft. It can be used in a clutch device provided with.

1 is a schematic vertical cross-sectional left side view of an image forming apparatus equipped with a clutch device according to an embodiment of the present invention. It is a perspective view around a clutch device. FIG. 3 is a vertical sectional side view of a clutch mechanism of the clutch device shown in FIG. 2. FIG. 4 is a vertical sectional side view of the clutch mechanism similar to FIG. 3, showing a state in which the connection between the driving gear and the driven shaft is released. It is a control chart figure which shows operation | movement of a clutch apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 10 Motor 30 Image forming part 32 Developing roller 50 Clutch apparatus 60 Clutch mechanism 61 Drive gear (drive shaft)
61a Boss 62 Driven shaft 62a Shaft 63 Clamping spring (clutch element)
70 Intermittent mechanism 71 Sleeve 72 Tooth 73 Claw 80 Solenoid 81 Solenoid flapper 90 Control unit

Claims (2)

A driving shaft and a driven shaft arranged in alignment on a common axis, a clutch element that is interposed between these shafts and generates a coupling action when the driving shaft rotates in a specific direction, and rotates together with the driving shaft in the specific direction In a clutch device comprising: a clutch mechanism provided with an intermittence mechanism that stops the clutch element that performs and interrupts power transmission from the driving shaft to the driven shaft; and a control unit that controls the operation of the intermittence mechanism;
The controller, when changing from the state where the rotation of the driving shaft is stopped to the state where only the driving shaft is rotated, in the state where the rotation of the driving shaft is stopped, without operating the intermittent mechanism, The rotation of the driving shaft is started in a state where the coupling action is established between the shaft and the driven shaft, and the intermittent mechanism is operated after at least one rotation of the clutch element to move the driving shaft from the driving shaft to the driven shaft. A clutch device that cuts off power transmission.   An image forming apparatus comprising the clutch device according to claim 1.

Images