JP2016038042A - Driving control device and image formation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a driving control device capable of reducing operation sound of locking means for locking a tooth-missing gear, and surely operating the locking means.SOLUTION: A driving control device 2 operates a solenoid 104 at predetermined timing, and transmits rotation from a motor 9 to a cam 111. The drive control device 2 includes a speed control gear 106 provided at a position of being on the same axial as a tooth-missing gear 102 and being engaged with a driving gear 101, and a one-way clutch 107 connecting the tooth-missing gear 102 and the speed control gear 106.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a drive control device having a clutch mechanism and an image forming apparatus having the drive control device.

  A comparative example of the drive control device 2 of the primary transfer roller 214 that can be brought into contact with and separated from the photosensitive drum 203 provided in the image forming apparatus 201 formed of a laser printer will be described below with reference to FIGS. 1 to 3 and FIGS. 7 to 9. explain.

  Four primary transfer rollers 214Y, 214M, 214C, and 214Bk are attached to the inner peripheral side of the intermediate transfer belt 206 shown in FIGS. Each primary transfer roller 214 is opposed to each photosensitive drum 203Y, 203M, 203C, 203Bk of the four-color process cartridge 202.

  The primary transfer roller 214 can be brought into contact with or separated from each photosensitive drum 203 by the contact / separation device 1 shown in FIGS. 3A to 3C provided on the inner peripheral portion of the intermediate transfer belt 206. ing. The contact and separation operations of the four primary transfer rollers 214 have three contact and separation modes shown in FIGS. 2A to 2C based on the print signal.

  The first contact and separation mode shown in FIG. 2A is a full separation state in which all the primary transfer rollers 214 are separated from the photosensitive drum 203. This is a mode in which the intermediate transfer belt 206 and the photosensitive drum 203 are separated from each other in the pre-rotation and post-rotation of the printing operation to eliminate the rubbing, thereby reducing the rubbing resistance and preventing the rubbing portion from being worn. is there.

  In the second contact and separation mode shown in FIG. 2B, the primary transfer roller 214Bk contacts the photosensitive drum 203Bk of the black Bk process cartridge 202Bk with the intermediate transfer belt 206 interposed therebetween. The remaining three primary transfer rollers 214Y, 214M, and 214C are in a monocolor contact state in which they are separated from the photosensitive drums 203Y, 203M, and 203C.

  This is a mode for primary transfer of the toner image on the surface of the photosensitive drum 203Bk from the black Bk photosensitive drum 203Bk to the outer peripheral surface of the intermediate transfer belt 206 in the mono-color printing operation. By preventing the photosensitive drums 203Y, 203M, and 203C that are not required for the printing operation from contacting the intermediate transfer belt 206, the rotation of the photosensitive drums 203Y, 203M, and 203C can be stopped.

  The third contact and separation mode shown in FIG. 2C is a full-color contact state in which all the primary transfer rollers 214 are in contact with the photosensitive drum 203, respectively. This is a mode for primarily transferring the toner images on the surface of the photosensitive drum 203 from all the photosensitive drums 203 onto the outer peripheral surface of the intermediate transfer belt 206 in the full color printing operation.

  Next, a configuration for switching the three contact and separation modes shown in FIGS. 2A to 2C will be described with reference to FIGS. As shown in FIGS. 3A to 3C, the four primary transfer rollers 214 are respectively connected to the four primary transfer rollers 214 shown in FIGS. 3A to 3C by the contact / separation device 1 provided on the inner peripheral portion of the intermediate transfer belt 206. Reciprocate in the vertical direction (vertical direction).

  The primary transfer roller 214 is attached to a support member 301 that rotatably supports each primary transfer roller 214. The support member 301 is slidably supported by a sliding portion 302 provided on a support frame (not shown) that rotatably supports the intermediate transfer belt 206. A boss 303 is provided at the upper end of each support member 301.

  A cam 111 is provided so as to be rotatable about a rotation center 111d. The cam 111 has three cam surfaces 111a, 111b, and 111c. A gear 110 is fixed coaxially with the rotation center 111d of the cam 111, and the cam 111 is continuously centered around the rotation center 111d through the gear 110 by the drive control device 2 shown in FIGS. Rotate every 120 degrees.

  Reference numeral 112 denotes a slider provided so as to be slidable in the left-right direction (horizontal direction) in FIGS. In the slider 112, the other end of the compression spring 113 whose one end is locked to the apparatus frame is abutted and locked to the abutting portion 112a provided on the slider 112. Thereby, the slider 112 is always urged toward the cam 111 by the extension force of the compression spring 113 in the right direction in FIGS.

  As a result, the contact surface 112b of the slider 112 contacts and slides on the three cam surfaces 111a, 111b, and 111c of the cam 111. The slider 112 has three stop positions shown in FIGS. 3A to 3C according to the three cam surfaces 111a, 111b, and 111c of the cam 111 with which the contact surface 112b contacts.

  As shown in FIGS. 3A to 3C, the slider 112 is formed with crank-shaped through holes 304Y, 304M, 304C, and 304Bk at positions corresponding to the four primary transfer rollers 214, respectively. . The crank-shaped through holes 304 are as follows. A boss 303 is provided so as to protrude from the end of the support member 301 that rotatably supports the primary transfer roller 214. The boss 303 is slidably inserted into each crank-shaped through hole 304. Accordingly, the primary transfer roller 214 is moved in the vertical direction (vertical direction) in FIGS. 3A to 3C depending on the position of the slider 112 in the horizontal direction in FIGS. 3A to 3C.

  As shown in FIGS. 3A to 3C, the crank shapes of the four through holes 304 provided in the slider 112 are as follows. The three positions shown in FIGS. 3A to 3C where the slider 112 stops correspond to the three contact and separation modes shown in FIGS. 2A to 2C. In this way, the four primary transfer rollers 214 are moved in the vertical direction in FIGS.

  As shown in FIGS. 3A to 3C, the cam 111 is rotated 120 degrees clockwise in FIGS. 3A to 3C. As a result, the through hole 304 can be switched from the full separation mode shown in FIG. 3A to the mono-color contact mode shown in FIG. 3B and further to the full-color contact mode shown in FIG. The crank shape is set.

  In contrast to the full separation mode shown in FIG. 3A, the mono-color contact mode shown in FIG. 3B is as follows. As shown in FIG. 2 (b), only the primary transfer roller 214Bk is perpendicular to the vertical direction of FIG. 3 (b) by the vertical shift amount d in FIG. 3 (b) of the crank shape of the through hole 304Bk shown in FIG. 3 (b). It moves toward the photosensitive drum 203Bk, which is lower in the direction, and comes into contact therewith.

  In the full-color contact mode shown in FIGS. 2C and 3C, all the primary transfer rollers 214 are moved to contact with the photosensitive drum 203 side.

  Next, the configuration of the drive control device 2 of the first comparative example will be described with reference to FIGS. In FIGS. 7A and 7B, reference numeral 101 denotes a drive gear. The drive gear 101 is rotated in a fixed direction in the clockwise direction of FIG. 7A by a motor 9 as a drive source that is controlled by the control unit 8 as a control means and rotates at a predetermined timing and rotation speed.

  Reference numeral 102 denotes a toothless gear. A locking portion 103 and a gear 102b are integrally formed on both sides of the partial gear 102. In this comparative example, as shown in Patent Document 1, the missing gear 102 has a locking portion 103, and the missing tooth portion 102a is not engaged with the drive gear 101 by the solenoid 104 and the tension spring 105. It can be stopped.

  When the solenoid 104 is released, the toothless gear 102 rotates counterclockwise in FIG. 7A due to the pulling force of the tension spring 105. As a result, the tooth portion 102 c of the toothless gear 102 meshes with the driving gear 101, and the rotational driving force is transmitted from the driving gear 101 to the toothless gear 102.

  When the toothless gear 102 meshes with the drive gear 101 and rotates once in the counterclockwise direction of FIG. 7A and the toothless portion 102 a faces the drive gear 101, the toothless gear 102 is pulled by the tension spring 105. It rotates in the counterclockwise direction of FIG. As a result, the locking portion 103 provided on the toothless gear 102 and the locking portion 104a of the solenoid 104 are locked, and the toothless gear 102 stops rotating. 7A and 7B, reference numeral 108 denotes a step gear in which two gears 108a and 108b are integrally formed. Reference numeral 109 denotes a gear that transmits the rotation of the step gear 108 to the gear 110.

  Next, the reduction ratio of the gear train 7 composed of the gears 102b, 108a, 108b, 109, 110 shown in FIGS. 7A and 7B will be described. The number of teeth of the gear train 7 including the gears 102b, 108a, 108b, 109, 110 is set so that the reduction ratio between the gear 102b and the gear 110 is 3: 1. Therefore, every time the segment gear 102 makes one rotation, as shown in FIGS. 3A to 3C, the cam 111 provided coaxially with the gear 110 is rotated by one third, that is, 120. It is designed to rotate by degrees (= 360 degrees / 3).

  Thereby, as shown to Fig.3 (a)-(c), it is possible to switch three cam positions. The locking and releasing of the locking portion 104a of the solenoid 104 shown in FIG. 7A and the locking portion 103 provided integrally with the toothless gear 102 is repeated. Thereby, as shown in FIGS. 2A to 2C, the primary transfer roller 214 can be shifted to a desired control position with respect to the photosensitive drum 203.

  Further, as a drive control device 2 having a similar function, there is a second comparative example in which two segmented gears 502 and 503 are combined as shown in FIGS. 8 (a) and 8 (b). In this comparative example, a missing tooth clutch including two missing gears 502 and 503 is used as shown in Patent Document 2.

  A locking portion 504 is integrally provided on one side of the toothless gear 502 shown in FIGS. 8 (a) and 8 (b). When the locking portion 104a of the solenoid 104 is locked to the locking portion 504, the missing tooth portion 502a of the missing gear 502 faces the drive gear 101, and the tooth portion 502c of the missing gear 502 becomes the driving gear 101. It is possible to stop without meshing.

  Further, a gear 503b is integrally provided on one side of the toothless gear 503, and a boss 503c is protruded on one side of the gear 503b. The missing tooth portion 503a of the missing gear 503 is opposed to the drive gear 101 by an urging force of a compression spring (not shown) provided between the missing gear 502 and the missing gear 503. The tooth portion 503d can be stopped in a state where it does not mesh with the drive gear 101.

  According to this comparative example, when the solenoid 104 is released, the toothless gear 502 starts to rotate by the biasing force of a compression spring (not shown) provided between the toothless gear 502 and the toothless gear 503. The tooth portion 502 c of the partial gear 502 meshes with the drive gear 101. A rotation stop portion (not shown) is formed between the partial gear 502 and the partial gear 503. When the partial gear 502 rotates by a predetermined rotation angle, the rotation stop portion acts and the partial gear 503 starts rotating.

  Then, the toothless gear 502 that meshes with the drive gear 101 rotates once in the counterclockwise direction of FIG. Then, the toothless portion 502 a of the toothless gear 502 is opposed to the driving gear 101 and the meshing with the driving gear 101 is released. Then, the locking portion 504 provided integrally with the toothless gear 502 and the locking portion 104a of the solenoid 104 are locked, and the rotation of the toothless gear 502 is stopped again.

  Subsequently, the toothless gear 503 rotates while compressing a compression spring (not shown) provided between the toothless gear 503 and the toothless gear 502, and the toothless portion 503a of the toothless gear 503 is driven. The engagement with the drive gear 101 is released facing the 101.

  One end of the tension spring 506 is locked to the device frame 3, and the other end is locked to a lever 505 that is pivotable about a pivot center 505a. The boss 503c provided so as to be able to come into contact with the lever 505 by the pulling force of the tension spring 506 is pressed by the lever 505 rotating around the rotation center 505a, and the toothless gear 503 rotates to the stop position.

  Note that the rotation range of the lever 505 around the rotation center 505a is regulated by a regulating member (not shown) provided at the rotation center 505a. Thus, the rotation of the lever 505 is prevented so that the lever 505 does not bias the boss 504c in a state where the toothless gear 503 is not meshed with the drive gear 101.

  Also in this comparative example, the three cam positions can be switched as shown in FIGS. 3A to 3C in the same manner as the drive control device 2 of the first comparative example. The locking and releasing of the locking portion 104a of the solenoid 104 shown in FIG. 8A and the locking portion 504 provided integrally with the intermittent gear 502 is repeated. Thereby, as shown in FIGS. 2A to 2C, the primary transfer roller 214 can be shifted to a desired control position with respect to the photosensitive drum 203.

JP-A-6-50406 JP-A-10-153247

  However, in each of the above comparative examples, the missing tooth clutch including the missing gears 102, 502, and 503 makes one rotation, and the meshing with the drive gear 101 is released immediately before returning to the locking position. For this reason, there were the following problems.

  9A to 9C, the load applied to the gear train 7 from the drive gear 101 to the gear 110 of the drive control device 2 shown in FIGS. 7 and 8 from the operation of the cam 111 and the slider 112 will be described. . 9A to 9C, the cam 111 rotates through the gear train 7 from the drive gear 101 to the gear 110 of the drive control device 2 shown in FIGS. 7 and 8, and FIGS. The state which transfers to three stop positions shown to c) is shown. A cam 111 indicated by a solid line in FIGS. 9A to 9C indicates a control completion position. A cam 111 indicated by a broken line indicates a position immediately before the completion of control.

The lengths of the compression springs 113 at the three stop positions shown in FIGS. 3A to 3C vary depending on the distances at which the cam surfaces 111a, 111b, and 111c of the cam 111 push the contact surface 112b of the slider 112. . Figure 9 (a) ~ the cam surface 111a from the rotational center 111d of the cam 111 shown in (c), 111b, the cam radius _r a to the vertex of _111c, r b, the equation (1) below the relation _{r c} .

[Equation 1]
r _a <r _b <r _c

Then, since the urging forces P _a , P _b , and P _c formed by the extension force of the compression spring 113 shown in FIGS. 9A to 9C are proportional to the compression distance of the compression spring 113, the following formula 2 The relationship shown in

[Equation 2]
P _a <P _b <P _c

Cam surfaces 111a, 111b, 111c of the cam 111 shown in FIGS. 9A to 9C, and an abutting surface 112b provided at the end of the slider 112 (the right end of FIGS. 9A to 9C) A frictional force acts on the contact portion. The frictional forces are μ × P _a , μ × P _b , and μ × P _c , respectively, where μ is the contact friction coefficient between the cam surfaces 111a, 111b, and 111c of the cam 111 and the contact surface 112b of the slider 112. Represented.

  From the state of the cam 111 at the position immediately before the completion of control indicated by the broken line in FIGS. 9A to 9C, the cam 111 is moved to the control completion position indicated by the solid line in FIGS. Rotate clockwise in FIGS. 9 (a) to 9 (c). For this purpose, the torque T calculated by the following equation 3 using the contact friction coefficient μ between the cam surfaces 111a, 111b, 111c of the cam 111 and the contact surface 112b of the slider 112 is required.

The urging forces P _a , P _b , and P _{c formed} by the extension force of the compression spring 113 are typically indicated by the urging force P, and cams from the rotation center 111d of the cam 111 to the apexes of the cam surfaces 111a, 111b, and 111c. radius _{r a,} indicated by r b, _{r c} a typically cam radius r.

[Equation 3]
T = μ × P × r

When the torques T _1a , T _1b , T _1c applied to the cam 111 at the three control positions shown in FIGS. 9A to 9C are compared, the following equation 4 is obtained from the equations 1 to 3. The relationship shown in

[Equation 4]
T _1a <T _1b <T _1c

  As a result, as shown in FIGS. 2A to 2C, it can be seen that the necessary torque T differs depending on the control position at which the primary transfer roller 214 is to be moved with respect to the photosensitive drum 203.

  In the missing tooth gear 102 of the first comparative example described above with reference to FIGS. 7A and 7B, the driving force by the driving gear 101 is not transmitted at the locking position where the missing tooth portion 102 a faces the driving gear 101. .

For this reason, in order to rotate to the locking position shown to Fig.7 (a), the urging | biasing force by the tension | pulling force of the tension spring 105 is utilized. Therefore, the urging force due to the pulling force of the tension spring 105 needs to overcome the torque T _1c that is the maximum value of the torques T _1a , T _1b , T _1c applied to the cam 111 shown in FIGS. .

At this time, torques T _2a , T _2b , and T _2c acting on the toothless gear 102 shown in FIGS. 7A and 7B are as follows. The torque due to tension of the tension spring 105 _{T sa, T sb,} and _{T sc.} Then, using the torques T _1a , T _1b and T _{1c applied} to the cam 111, the reduction ratio between the gear 102b provided integrally with the toothless gear 102 and the gear 110 rotating integrally with the cam 111 is 3: In consideration of 1, each is expressed by the following equation (5).

[Equation 5]
T _2a = T _sa -3 × T _1a
T _2b = T _sb -3 × T _1b
T _2c = T _sc -3 × T _1c

The relationship among the torques T _2a , T _2b , T _2c acting on the toothless gear 102 shown in FIGS. 7A and 7B using the formula 4 and the formula 5 is expressed by the following formula 6.

[Equation 6]
T _2a > T _2b > T _2c

  As shown in FIGS. 9 (a) and 9 (b), a control position in which the load for pressing the cam surfaces 111a and 111b of the cam 111 by the extension force of the compression spring 113 is relatively small is considered. Further, as shown in FIG. 9 (c), a control position where a load for pressing the cam surface 111c of the cam 111 by the extension force of the compression spring 113 is relatively large is considered. In the control positions shown in FIGS. 9A and 9B, the tension force of the tension spring 105 shown in FIG. 7A is larger than that shown in FIG. 9C. As a result, the rotational torque applied to the missing gear 102 is increased.

At this time, the cam shown in FIGS. 9A to 9C when the cam 111 rotating integrally with the gear 110 is rotated by the pulling force of the tension spring 105 shown in FIGS. 7A and 7B. The angular velocities ω _a , ω _b , and ω _c of 111 are expressed by the following equation (7).

[Equation 7]
ω _a > ω _b > ω _c

Further, the angular velocities ω _a , ω _b , and ω _c are compared with the angular velocities ω _s during steady rotation of the cam 111. Then, as shown in FIGS. 7A and 7B, while the tooth portion 102 c of the toothless gear 102 meshes with the drive gear 101 and rotates, the motor 9 serving as the drive source of the gear 110 is driven by the drive gear 101. And the gear 110 that rotates integrally with the cam 111 is rotated via the gear train 7.

  On the other hand, one end of the tension spring 105 is locked to a boss 103 a protruding from one side of a locking portion 103 provided integrally with the toothless gear 102, and the other end is locked to the device frame 3.

  In some cases, the toothless portion 102a of the toothless gear 102 faces the drive gear 101 and the rotational driving force by the drive gear 101 is cut off. In that case, the toothless gear 102 is rotated counterclockwise in FIG. 7A by the pulling force (biasing force) of the tension spring 105 that is the driving source of the gear 110, and the cam 111 is connected to the cam 111 via the gear train 7. The gear 110 that rotates integrally is rotated. Therefore, the driving source of the gear 110 is continuously switched from the driving gear 101 meshing with the tooth portion 102c of the toothless gear 102 to the pulling force (biasing force) of the tension spring 105.

In this case, inertia acts on the gear train 7 including the intermittent gear 102, the step gear 108, and the gears 109 and 110 shown in FIGS. 7 (a) and 7 (b). For this reason, the angular velocities ω _a , ω _b , ω _c of the cam 111 shown in FIGS. 9A to 9C and the angular velocities ω _s during steady rotation of the cam 111 are represented by the following equation (8).

[Equation 8]
ω _a > ω _b > ω _c ≈ω _s

  A toothless gear 102 meshes with a gear 110 that rotates integrally with a cam 111, and a gear train 7 that includes a gear 109 and a step gear 108. In some cases, the toothless portion 102a of the toothless gear 102 faces the drive gear 101 and the rotational driving force by the drive gear 101 is cut off.

In this case, the angular speed ω _t of the toothless gear 102 when it is rotated by the pulling force of the tension spring 105 is the angular speed of the toothless gear 102 when the toothed portion 102c is meshed with the drive gear 101 and rotated. faster than ω _d.

  As a result, the following problems occurred in the first comparative example shown in FIGS. It occurs at the moment when the locking portion 104a of the solenoid 104 comes into contact with the locking portion 103 provided integrally on one side of the toothless gear 102 when transitioning to the control position shown in FIGS. 7 (a) and 7 (b). There was a case where the collision sound to be increased.

  In addition, due to the impact caused by the collision between the locking portion 103 of the toothless gear 102 and the locking portion 104a of the solenoid 104, the locking portion 104a of the solenoid 104 gets over the locking portion 103 without being caught, and a malfunction occurs. This is a design constraint.

Further, in the second comparative example shown in FIGS. 8A and 8B, when the tension force of the tension spring 506 is increased corresponding to the downstream load of the gear train 7 including the step gear 108 and the gears 109 and 110. There is. Angular velocity omega _t is 7 toothless gear 503 in case (a), becomes as fast as in the first comparative example shown in (b).

  As a result, when a compression spring (not shown) provided between the missing gear 502 and the missing gear 503 shown in FIGS. 8A and 8B is compressed to the close contact height, the engagement is performed via the missing gear 502. The rotational force is transmitted to the stop 504. For this reason, the locking portion 504 may get over the locking portion 104a of the solenoid 104.

  Furthermore, the missing tooth clutch mechanism using the missing gears 102, 502, and 503 shown in FIGS. 7 and 8 cannot reversely rotate due to its structure. For example, the rotation direction of the drive gear 101 shown in FIGS. 7 and 8 is reversed, and the primary transfer roller 214 is moved from the fully separated mode shown in FIG. 2A to the photosensitive drum 203 as shown in FIG. Consider a case where it is desired to shift to the full color contact mode.

  However, for example, the toothless gear 102 of the first comparative example shown in FIGS. 7A and 7B is attached only in the forward rotation direction (counterclockwise direction of FIG. 7A) by the pulling force of the tension spring 105. It is energized. For this reason, since it is contrary to the reverse rotation direction of the drive gear 101 (counterclockwise direction in FIG. 7A), the reverse rotation of the drive gear 101 cannot be continued.

  As a result, there is a restriction that the control position of the primary transfer roller 214 relative to the photosensitive drum 203 can be changed only in a preset order, and the time required for the mode switching operation becomes long.

  For example, in the case of each comparative example, when the primary transfer roller 214 is changed from the full separation mode shown in FIG. 2A to the full color contact mode shown in FIG. It must go through the monochromatic contact mode shown in 2 (b).

  The present invention solves the above-mentioned problems, and an object of the present invention is to reduce the operation noise of the locking means for locking the tooth-missing gear, and to drive the locking means reliably. Is to provide.

  A typical configuration of a drive control device according to the present invention for achieving the above object is provided at a position where a driven body to be rotationally driven, a drive gear connected to a drive source, and the drive gear can be meshed with each other. And a latching means for stopping the toothless portion of the toothless gear in a state where it does not mesh with the drive gear, and a biasing means for biasing the toothless gear in the rotational direction. In the drive control device that operates the locking means at a predetermined timing to transmit the rotation from the drive source to the driven body, the drive control device is provided at a position that can be meshed with the drive gear on the same axis as the intermittent gear. And a rotation inhibiting means for connecting the segmented gear and the speed control gear.

  According to the above configuration, the rotational speed of the missing gear can be reduced. As a result, the collision speed to the locking means can be reduced, so that the collision sound can be reduced. In addition, the drive control device can be prevented from malfunctioning because it does not get over the locking means due to the impact of the collision.

1 is a cross-sectional explanatory diagram illustrating a configuration of an image forming apparatus including a drive control device according to the present invention. (A) is sectional explanatory drawing which shows the state of the position of a transfer means in all separation mode. (B) is a cross-sectional explanatory view showing the state of the transfer means in the mono-color mode. (C) is a cross-sectional explanatory view showing the state of the transfer means in the full color mode. (A) is sectional explanatory drawing which shows the state of a cam and a slider at the time of the position of a transfer means in all separation mode. (B) is a cross-sectional explanatory view showing the state of the cam and slider when the position of the transfer means is in the mono-color mode. (C) is a cross-sectional explanatory view showing the state of the cam and the slider when the transfer means is in the full color mode. (A) is front explanatory drawing which shows the structure of 1st Embodiment of the drive control apparatus which concerns on this invention. (B) is side explanatory drawing which shows the structure of 1st Embodiment of the drive control apparatus which concerns on this invention. (A) is a figure explaining the torque which acts on the cam at the time of the position of a transfer means in all separation mode in 1st Embodiment. (B) is a diagram illustrating the torque acting on the cam when the position of the transfer means is in the mono-color mode in the first embodiment. (C) is a diagram illustrating the torque acting on the cam when the position of the transfer means is in the full color mode in the first embodiment. It is front explanatory drawing which shows the structure of 2nd Embodiment of the drive control apparatus which concerns on this invention. (B) is side explanatory drawing which shows the structure of 2nd Embodiment of the drive control apparatus which concerns on this invention. (A) is front explanatory drawing which shows the structure of the drive control apparatus of a 1st comparative example. (B) is side explanatory drawing which shows the structure of the drive control apparatus of a 1st comparative example. (A) is front explanatory drawing which shows the structure of the drive control apparatus of a 2nd comparative example. (B) is side explanatory drawing which shows the structure of the drive control apparatus of a 2nd comparative example. (A) is a figure explaining the torque which acts on the cam at the time of the position of a transfer means in all separation mode in a comparative example. (B) is a diagram for explaining the torque acting on the cam when the position of the transfer means is in the mono-color mode in the comparative example. (C) is a diagram illustrating torque acting on the cam when the position of the transfer unit is in the full color mode in the comparative example.

  An embodiment of an image forming apparatus provided with a drive control apparatus according to the present invention will be specifically described with reference to the drawings.

[First Embodiment]
<Image forming apparatus>
First, the configuration of a first embodiment of an image forming apparatus including a drive control device according to the present invention will be described with reference to FIGS. FIG. 1 is an explanatory cross-sectional view showing the configuration of an image forming apparatus 201 composed of a laser printer. In FIG. 1, 202Y, 202M, 202C, and 202Bk are four process cartridges corresponding to four colors of yellow Y, magenta M, cyan C, and black Bk, respectively. For convenience of explanation, the process cartridges 202Y, 202M, 202C, and 202Bk may be described using the process cartridge 202 as a representative. The same applies to other image forming process means.

  Inside the process cartridge 202, a photosensitive drum 203 serving as an image carrier on which a toner image is carried is provided. Around the photosensitive drum 203, a charging roller 4 is provided as a charging means for uniformly charging the surface of the photosensitive drum 203.

  Further, a laser scanner 204 serving as an image exposure unit that irradiates the surface of the photosensitive drum 203 uniformly charged by the charging roller 4 with laser light 204a corresponding to image information is provided. Further, a developing roller 5 serving as a developer carrying member is a developing unit that supplies toner serving as a developer onto the surface of the photosensitive drum 203 on which an electrostatic latent image is formed by being irradiated with laser light 204a by a laser scanner 204. Is provided.

  The developing roller 5 supplies toner as a developer onto the surface of the photosensitive drum 203. As a result, the electrostatic latent image formed on the surface of the photosensitive drum 203 by the laser beam 204a emitted from the laser scanner 204 based on the image information is developed as a toner image by a known electrophotographic process.

  An intermediate transfer belt 206 is provided as an intermediate transfer member that is rotatably supported by rollers 206 a and 206 b so as to face each photosensitive drum 203. A primary transfer roller 214 serving as a primary transfer unit (transfer unit) is provided on the inner peripheral portion of the intermediate transfer belt 206. The primary transfer roller 214 is controlled by a cam 111 serving as a driven body that is rotationally driven by a drive control device 2 shown in FIGS. 4A and 4B and described later. Each photosensitive drum 203 is configured to be able to contact and separate through an intermediate transfer belt 206.

  As shown in FIG. 2, each primary transfer roller 214 is configured to abut against or separate from each photosensitive drum 203 through an intermediate transfer belt 206 as shown in FIG. The

  The toner image developed on the surface of each photosensitive drum 203 is transferred onto the outer peripheral surface of the intermediate transfer belt 206 by applying a primary transfer bias voltage to each primary transfer roller 214. By continuously transferring each color onto the outer peripheral surface of the intermediate transfer belt 206, toner images of four colors are formed on the outer peripheral surface of the intermediate transfer belt 206. The toner image formed on the outer peripheral surface of the intermediate transfer belt 206 is conveyed to a secondary transfer nip portion opposed to a secondary transfer roller 207 serving as a secondary transfer unit.

  On the other hand, a feeding unit 209 that can store a sheet 208 is provided below the image forming apparatus 201. The feeding roller 210 disposed near the leading end of the sheet 208 accommodated in the feeding unit 209 rotates.

  Thus, the sheets 208 are separated and fed one by one in cooperation with a separation unit (not shown). Thereafter, the sheet is conveyed by the registration roller 211 to the secondary transfer nip where the intermediate transfer belt 206 and the secondary transfer roller 207 further downstream contact each other at a predetermined timing.

  Subsequently, when a secondary transfer bias voltage is applied to the secondary transfer roller 207, the toner image on the outer peripheral surface of the intermediate transfer belt 206 is transferred onto the sheet 208 conveyed to the secondary transfer nip portion at a predetermined timing. Is done.

  The sheet 208 on which the unfixed toner image is transferred is further conveyed downstream, and is heated and pressed by a fixing device 212 serving as a fixing unit, and the toner on the sheet 208 is melted, whereby the toner image is fixed on the sheet 208. Is done. Thereafter, the sheet 208 is discharged onto the discharge tray 213. A toner image is formed on the surface of the sheet 208 by the series of image forming operations described above.

<Contact / separation mode of transfer means>
Next, the contact and separation modes of the primary transfer rollers 214 with respect to the photosensitive drums 203 will be described with reference to FIGS. Four primary transfer rollers 214Y, 214M, 214C, and 214Bk are attached to the intermediate transfer belt 206 so as to face the photosensitive drums 203 of the four-color process cartridges 202, respectively.

  Each primary transfer roller 214 can be brought into contact with or separated from each photosensitive drum 203 via the intermediate transfer belt 206 by the contact / separation device 1 provided on the inner peripheral portion of the intermediate transfer belt 206.

  The contact and separation operation of each primary transfer roller 214 with respect to each photosensitive drum 203 has three contact and separation modes shown in FIGS. 2A to 2C based on a print signal. The first contact and separation mode shown in FIG. 2A is a full separation mode in which all the primary transfer rollers 214 are separated from the respective photosensitive drums 203.

  This is a mode in which the intermediate transfer belt 206 and the photosensitive drum 203 are separated from each other in the pre-rotation and post-rotation of the printing operation to eliminate the rubbing, thereby reducing the rubbing resistance and preventing the rubbing portion from being worn. is there.

  In the second contact and separation mode shown in FIG. 2B, the primary transfer roller 214Bk contacts the photosensitive drum 203Bk of the black Bk process cartridge 202Bk with the intermediate transfer belt 206 interposed therebetween. The remaining three primary transfer rollers 214Y, 214M, and 214C are in a monochromatic contact mode that is separated from the surface of each photosensitive drum 203.

  This is a mode for primary transfer of the toner image on the surface of the photosensitive drum 203Bk from the photosensitive drum 203Bk of black Bk to the outer peripheral surface of the intermediate transfer belt 206 in the monocolor printing operation.

  By preventing the photosensitive drums 203Y, 203M, and 203C that are not required for the printing operation from contacting the intermediate transfer belt 206, the rotation of the photosensitive drums 203Y, 203M, and 203C can be stopped.

  The third contact and separation mode shown in FIG. 2C is a full-color contact mode in which all the primary transfer rollers 214 are in contact with the surface of the photosensitive drum 203 with the intermediate transfer belt 206 interposed therebetween. This is a mode for primarily transferring the toner images on the surface of all the photosensitive drums 203 onto the outer peripheral surface of the intermediate transfer belt 206 in the full color printing operation.

<Contacting / separating device>
Next, the configuration of the contact / separation apparatus 1 that switches the three contact and separation modes shown in FIGS. 2 (a) to 2 (c) will be described using FIGS. 3 (a) to 3 (c). 3A to 3C show the four primary transfer rollers 214 in the vertical direction (vertical direction) in FIGS. 3A to 3C by the contact / separation device 1 provided on the inner peripheral portion of the intermediate transfer belt 206. FIG. ) Shows how to reciprocate.

  As shown in FIGS. 3A to 3C, each primary transfer roller 214 is rotatably supported by each support member 301. The supporting member 301 is supported by a sliding portion 302 provided on the apparatus frame of the intermediate transfer belt 206 so as to be slidable in the vertical direction in FIGS. A boss 303 projects from the end of the support member 301.

  A cam 111 is rotatably supported around a rotation center 111d provided on the apparatus frame of the intermediate transfer belt 206. The cam 111 has three cam surfaces 111a, 111b, and 111c and has a substantially triangular shape. A gear 110 that rotates integrally with the cam 111 is provided coaxially with the rotation center 111 d of the cam 111. The gear 110 is continuously rotated by 120 degrees by a drive control device 2 shown in FIGS. 4A and 4B and described later.

  3A to 3C, reference numeral 112 denotes a slider slidably attached in the left-right direction (horizontal direction) in FIGS. 3A to 3C. The slider 112 is attached so as to be slidable in the left-right direction (horizontal direction) in FIGS. 3A to 3C by moving means provided in an apparatus frame (not shown).

  The slider 112 has one end locked to the apparatus frame, and the other end of the compression spring 113 locked to a contact portion 112 a provided on the slider 112. As a result, the slider 112 is constantly biased toward the cam 111 by the extension force of the compression spring 113.

  On the other hand, as shown in FIGS. 3A to 3C, cam surfaces 111a, 111b, and 111c provided at three corners of the substantially triangular cam 111 are 120 degrees each about the rotation center 111d. It is arranged at a shifted position.

  Then, the cam surfaces 111a, 111b, 111c of the cam 111 that rotates integrally with the gear 110 around the rotation center 111d abuts and slides on the contact surface 112b of the slider 112. Accordingly, the slider 112 is configured to be capable of reciprocating in the left-right direction in FIGS. 3A to 3C against the urging force generated by the extension force of the compression spring 113.

  When the cam surfaces 111a, 111b, and 111c of the cam 111 stop at the posture positions shown in FIGS. 3A to 3C, the slider 112 corresponds to the three cam surfaces 111a, 111b, and 111c of the cam 111 in FIG. It has three stop positions shown in a) to (c).

  The slider 112 is formed with crank-shaped through holes 304Y, 304M, 304C, and 304Bk corresponding to the four primary transfer rollers 214, respectively. A boss 303 provided at the end of the support member 301 that supports the primary transfer roller 214 is slidably inserted into the through holes 304Y, 304M, 304C, and 304Bk of the slider 112. The boss 303 moves along the crank shape of the through holes 304Y, 304M, 304C, 304Bk.

  The crank shape of each through hole 304 is as follows. The boss 303 provided at the end of the support member 301 moves in each through hole 304 depending on the position of the slider 112 in the left-right direction (horizontal direction) in FIGS. As a result, the primary transfer roller 214 is moved in the vertical direction (vertical direction) in FIGS.

  The crank shapes of the four through holes 304 provided in the slider 112 are as follows. As shown in FIGS. 3A to 3C, the three positions where the slider 112 stops correspond to the three contact and separation modes shown in FIGS. 2A to 2C. The four primary transfer rollers 214 are moved so as to be in each mode.

  As shown in FIGS. 3A to 3C, the cam 111 is rotated by 120 degrees. As a result, as shown in FIGS. 2A to 2C and FIGS. 3A to 3C, switching is performed in the order of the full separation mode → the monocolor contact mode → the full color contact mode. In this way, the crank shape of the through hole 304 is set.

  The monochromatic contact mode shown in FIGS. 2B and 3B is as follows with respect to the full separation mode shown in FIGS. 2A and 3A. Only the primary transfer roller 214Bk of the black Bk moves downward (vertically in the vertical direction) in FIG. 3B by the crank-shaped shift amount d of the through hole 304Bk. As a result, in the monochrome contact mode, only the primary transfer roller 214Bk of black Bk contacts the surface of the photosensitive drum 203Bk with the intermediate transfer belt 206 interposed therebetween.

  Further, in the full color contact mode shown in FIGS. 2C and 3C, the operation is as follows. All the primary transfer rollers 214 are placed on the surface of the photosensitive drum 203 via the intermediate transfer belt 206 in the same manner as the primary transfer roller 214Bk of the black Bk in the monochromatic contact mode shown in FIGS. 2B and 3B. Abut.

<Drive control device>
Next, the configuration of the drive control device 2 will be described with reference to FIG. In the drive control device 2 shown in FIGS. 4A and 4B, the control unit 8 serving as the control unit operates the solenoid 104 serving as the locking unit at a predetermined timing. Thus, the rotation is transmitted from the motor 9 serving as a driving source to the cam 111 serving as a driven body via the driving gear 101 and the gear train 7.

  4 (a) and 4 (b), reference numeral 101 denotes a driving gear that is connected to a motor 9 or the like serving as a driving source and is rotationally driven. The drive gear 101 is rotated in a fixed direction indicated by the clockwise direction in FIG. 4A by a motor 9 serving as a drive source that rotates at a predetermined timing and rotation speed.

  4 (a) and 4 (b), reference numeral 102 denotes an intermittent gear in which a locking portion 103 and a gear 102b are integrally provided on both sides. The partial gear 102 is provided at a position where it can mesh with the drive gear 101.

  On one side of the partial gear 102, there is provided a locking portion 103 capable of locking the locking portion 104a of the solenoid 104 serving as locking means. As shown in FIG. 4A, the missing tooth portion 102a of the toothless gear 102 faces the drive gear 101 in a state where the locking portion 104a of the solenoid 104 is locked to the locking portion 103 of the toothless gear 102. The tooth portion 102c stops in a state where it does not mesh with the drive gear 101.

  A locking portion 103 provided integrally with the toothless gear 102 is provided with a tension spring 105 serving as a biasing means for biasing the toothless gear 102 in the counterclockwise direction of FIG. A boss 103a to which one end of the boss 103a is locked is projected.

  The other end of the tension spring 105 is locked to the device frame 3. The toothless gear 102 is pulled by a tension spring 105 with the locking portion 104 a of the solenoid 104 locked by the locking portion 103. As a result, as shown in FIG. 4A, the toothless portion 102a of the toothless gear 102 faces the drive gear 101, and the tooth portion 102c stops in a state where it does not mesh with the drive gear 101.

  The solenoid 104 is driven to unlock the locking portion 104a and the locking portion 103 of the toothless gear 102. Then, the toothless gear 102 is rotated counterclockwise in FIG. 4A by the pulling force of the tension spring 105. As a result, the tooth portion 102 c of the toothless gear 102 meshes with the driving gear 101, and the rotational driving force of the driving gear 101 is transmitted to the toothless gear 102.

  The toothless gear 102 meshed with the drive gear 101 makes one rotation in the counterclockwise direction of FIG. 4A, and the toothless portion 102 a faces the drive gear 101. Then, the toothless gear 102 rotates counterclockwise in FIG. 4A by the pulling force of the tension spring 105. Then, the locking portion 103 of the toothless gear 102 is locked to the locking portion 104a of the solenoid 104, and the rotation of the toothless gear 102 stops.

  As shown in FIG. 4B, a speed control gear 106 is provided at a position that can be meshed with the drive gear 101 coaxially with the toothless gear 102. The speed control gear 106 of this embodiment is always meshed with the drive gear 101. As a result, while the tooth portion 102c of the partial gear 102 is engaged with the drive gear 101 and rotated, the speed control gear 106 and the partial gear 102 rotate at the same angular velocity via the drive gear 101.

  The speed control gear 106 is connected to the toothless gear 102 via a one-way clutch 107 serving as rotation suppression means. The one-way clutch 107 idles when the relative rotational direction of the partial gear 102 and the speed control gear 106 matches the rotational direction of the partial gear 102. The one-way clutch 107 is locked when the speed control gear 106 tries to rotate in a direction in which the relative rotation direction of the toothless gear 102 and the speed control gear 106 is opposite to the rotation direction of the toothless gear 102. It is configured as follows.

  That is, in the one-way clutch 107, the toothless gear 102 can rotate only in the reverse direction with respect to the rotation direction of the speed control gear 106. In this embodiment, a one-way clutch 107 using a planetary gear is used. In a state where the locking portion 103 of the missing gear 102 is locked to the locking portion 104a of the solenoid 104 and the rotation of the missing gear 102 is stopped, the speed of the missing gear 102 is controlled by the action of the one-way clutch 107. The gear 106 idles. Thereby, the drive operation of the drive control device 2 is not hindered.

  4 (a) and 4 (b), reference numeral 108 denotes a step gear in which two gears 108a and 108b are integrally formed. Reference numeral 109 denotes a gear that transmits the rotation of the step gear 108 to the gear 110. Reference numeral 111 denotes a cam shown in FIGS. 3A to 3C and rotates integrally with the gear 110 via the rotating shaft 6. As shown in FIGS. 3A to 3C, the stop position of the slider 112 urged by the extension force of the compression spring 113 is controlled by the rotation of the cam 111 that rotates integrally with the gear 110.

  The cam surfaces 111a, 111b, and 111c of the cam 111 that rotate integrally with the gear 110 abut against the contact surface 112b of the slider 112 and slide the slider 112 against the extension force of the compression spring 113 as shown in FIG. ) To (c) in the horizontal direction. As a result, as shown in FIGS. 2A to 2C and FIGS. 3A to 3C, the primary transfer roller 214 is brought into contact with the surface of the photosensitive drum 203 through the intermediate transfer belt 206, or Switch between three modes to switch the separation. The force acting on the cam 111 by the extension force of the compression spring 113 is the same as described in the first and second comparative examples.

<Reduction ratio of gear train>
Next, the reduction ratio of the gear train 7 composed of the gears 102b, 108a, 108b, 109, 110 of the drive control device 2 shown in FIGS. 4 (a) and 4 (b) will be described. As shown in FIGS. 4A and 4B, the gear train 7 of the drive control device 2 includes gears 102b, 108a, 108b, 109, 110. The gear train 7 includes gears 102b, 108a, 108b, 108b, 108b, 108b, 108b, 108b, 108b, 108b, 108b, 108b, 108b, 108b so that the reduction ratio between the gear 102b provided integrally with the toothless gear 102 and the gear 110 rotating integrally with the cam 111 is 3: 1. 109 and 110 teeth are set. Accordingly, each time the segment gear 102 rotates once, the cam 111 fixed coaxially with the gear 110 rotates one third. That is, it rotates by 120 degrees (360 degrees / 3).

  In the present embodiment, as shown in FIGS. 3A to 3C, the contact / separation device 1 has three (at least two) control positions depending on the rotation angle of the cam 111. Then, a gear train 7 from the toothless gear 102 to the cam 111 so as to switch three (at least two) control positions of the contact / separation device 1 by one rotation of the toothless gear 102 shown in FIG. The reduction ratio is set.

  Accordingly, the cam 111 can switch the control positions of the three cams 111 of the contact / separation device 1 shown in FIGS. 3A to 3C every time the toothless gear 102 makes one rotation. The engagement and release of the engaging portion 104a of the solenoid 104 and the engaging portion 103 of the intermittent gear 102 shown in FIG. As a result, as shown in FIGS. 2A to 2C, the primary transfer roller 214 can be shifted to a desired control position with respect to the surface of the photosensitive drum 203 with the intermediate transfer belt 206 interposed therebetween.

<Load applied to the gear train>
Next, the load applied to the gear train 7 composed of the gears 102b, 108a, 108b, 109, 110 of the drive control device 2 by the rotation of the cam 111 and the moving operation of the slider 112 will be described with reference to FIG. FIGS. 5A to 5C show a state in which the cam 111 rotates 120 degrees each time the missing gear 102 rotates once and shifts to the three stop positions shown in FIGS. 3A to 3C. Show. 5 (a) to 5 (c) show a solid line cam 111 and a broken line cam 111, and the solid line shows a case where the cam 111 is at the control completion position. A broken line indicates the position of the cam 111 immediately before the completion of control.

The lengths of the compression springs 113 at the three control positions shown in FIGS. 3A to 3C vary depending on the distances at which the cam surfaces 111a, 111b, and 111c of the cam 111 push the contact surface 112b of the slider 112. Each cam surface 111a from the rotational center 111d of the cam 111 in the present embodiment, 111b, the cam radius _r a to the vertex of _111c, r b, the following numbers to indicate the _{r c} in FIG. 5 (a) ~ (c) It is set as the relationship of 9 formulas.

[Equation 9]
r _a <r _b <r _c

Then, since the urging forces P _a , P _b , and P _c due to the extension force of the compression spring 113 are proportional to the compression distance of the compression spring 113, the relationship shown by the following formula 10 is established.

[Equation 10]
P _a <P _b <P _c

Cam surfaces 111a, 111b, 111c of the cam 111 shown in FIGS. 5A to 5C, and an abutting surface 112b provided at the end of the slider 112 (the right end of FIGS. 5A to 5C) A frictional force acts on the contact portion. The frictional forces are μ × P _a , μ × P _b , and μ × P _c , respectively, where μ is the contact friction coefficient between the cam surfaces 111a, 111b, and 111c of the cam 111 and the contact surface 112b of the slider 112. Represented.

  The cam 111 is moved from the state of the cam 111 at the position immediately before the completion of control indicated by the broken line in FIGS. 5A to 5C to the control completion position indicated by the solid line in FIGS. Rotate clockwise in FIGS. 5 (a) to 5 (c).

For this purpose, the torque T expressed by the following equation 11 is required using the contact friction coefficient μ between the cam surfaces 111a, 111b, 111c of the cam 111 and the contact surface 112b of the slider 112. The urging forces P _a , P _b , and P _{c formed} by the extension force of the compression spring 113 are typically indicated by the urging force P, and cams from the rotation center 111d of the cam 111 to the apexes of the cam surfaces 111a, 111b, and 111c. radius _{r a,} indicated by r b, _{r c} a typically cam radius r.

[Equation 11]
T = μ × P × r

When the torques T _1a , T _1b , and T _1c applied to the cam 111 at the three control positions shown in FIGS. 5A to 5C are compared, the following equation 12 is obtained from the equations 9 to 11: The relationship shown in

[Equation 12]
T _1a <T _1b <T _1c

As a result, as shown in FIGS. 2A to 2C, it can be seen that the necessary torque T differs depending on the control position at which the primary transfer roller 214 is to be moved with respect to the photosensitive drum 203. As shown in FIG. 4A, in the missing gear 102, the driving force by the driving gear 101 is not transmitted at the locking position where the missing tooth portion 102a faces the driving gear 101. Therefore, in order to rotate to the locking position shown in FIG. 4A, the urging force by the pulling force of the tension spring 105 is the torque T _1a , T _1b , applied to the cam 111 shown in FIGS. it is necessary to overcome the torque _{T 1c} is the maximum value of T _1c.

At this time, torques T _2a , T _2b , T _2c acting on the toothless gear 102 shown in FIG. 4A are as follows. The torque due to tension of the tension spring 105 _{T sa, T sb,} and _{T sc.} Then, using the torques T _1a , T _1b and T _{1c applied} to the cam 111, the reduction ratio between the gear 102b provided integrally with the toothless gear 102 and the gear 110 rotating integrally with the cam 111 is 3: Considering 1, each is expressed by the following equation (13).

[Equation 13]
T _2a = T _sa -3 × T _1a
T _2b = T _sb -3 × T _1b
T _2c = T _sc -3 × T _1c

The relationship among the torques T _2a , T _2b , T _2c acting on the toothless gear 102 shown in FIG. 4A using the formula 12 and the formula 13 is expressed by the following formula 14.

[Formula 14]
T _2a > T _2b > T _2c

  As shown in FIGS. 5 (a) and 5 (b), this takes into account a control position in which the load for pressing the cam surfaces 111a and 111b of the cam 111 by the extension force of the compression spring 113 is relatively small. Further, as shown in FIG. 5C, a control position where a load for pressing the cam surface 111c of the cam 111 by the extension force of the compression spring 113 is relatively large is considered. In the control positions shown in FIGS. 5A and 5B, the pulling force of the tension spring 105 shown in FIG. 4A is larger than that in the control position shown in FIG. As a result, the rotational torque applied to the missing gear 102 is increased.

  Thus, when the cam 111 is rotated via the gear train 7 by the tension of the tension spring 105 shown in FIG. 4A, torque for increasing the angular velocity ω of the cam 111 is applied. For this reason, the gear train 7 downstream of the toothless gear 102 including the cam 111 tends to rotate faster than the rotational speed given from the drive gear 101 by the pulling force of the tension spring 105.

  In the present embodiment, as shown in FIG. 4B, the speed control gear 106 is connected to the intermittent gear 102 via the one-way clutch 107. The gear train 7 on the downstream side of the intermittent gear 102 including the cam 111 tends to rotate faster than the rotational speed given from the drive gear 101 by the pulling force of the tension spring 105. In this state, the toothless gear 102 tries to rotate ahead of the drive gear 101. In this case, the relative rotation direction of the partial gear 102 and the speed control gear 106 is opposite to the rotation direction of the partial gear 102 and the rotation direction of the speed control gear 106. For this reason, the one-way clutch 107 is locked.

  As a result, the toothless gear 102 rotates at an angular speed equal to the angular speed of the speed control gear 106. That is, it rotates at the angular velocity when the toothless gear 102 and the drive gear 101 mesh. Therefore, the angular velocity of the toothless gear 102 does not increase as in the comparative examples shown in FIGS.

  Thus, the toothless gear 102 can always rotate at a constant angular velocity regardless of the load or reaction force applied to the cam 111. Thereby, it is possible to prevent a collision sound or malfunction when the locking portion 104a and the locking portion 103 of the solenoid 104 are locked in the comparative examples shown in FIGS.

  Further, as shown in FIGS. 3A to 3C, when the cam 111 having a plurality of control positions is operated, the difference in the drive torque of the cam 111 at each control position of the cam 111 is a missing gear. Does not affect the angular velocity of 102. Accordingly, parameters such as the tension spring 105 shown in FIG. 4A and the compression spring 113 shown in FIGS. 3A to 3C can be set with a sufficient margin.

  Further, according to the present embodiment, the drive gear 101 shown in FIG. 4A is reversely rotated in the counterclockwise direction of FIG. 4A so that the toothless gear 102 is rotated in the clockwise direction of FIG. Reverse rotation is possible. When the drive gear 101 is reversely rotated counterclockwise in FIG. 4A, the speed control gear 106 that is always meshed with the drive gear 101 also starts reverse rotation. At this time, the one-way clutch 107 that connects the speed control gear 106 and the toothless gear 102 is locked because the relative rotation direction of the speed control gear 106 and the toothless gear 102 is the reverse direction. As a result, the toothless gear 102 rotates counterclockwise in FIG. 4A while resisting the pulling force of the tension spring 105 shown in FIG.

  In the present embodiment, the drive gear 101 that is rotationally driven by the motor 9 that is a drive source controlled by the control unit 8 is rotated in the forward direction shown in the clockwise direction in FIG. It is possible to switch to the reverse rotation shown in the clockwise direction. As a result, from the full separation mode shown in FIGS. 2A and 3A that could not be executed in the comparative examples shown in FIGS. It is possible to directly transition to the contact mode, and the operation time can be shortened.

  Note that the one-way clutch 107 of the present embodiment can be appropriately selected from a ratchet type one-way clutch, a torque limiter, and the like, which are lower in manufacturing cost, in accordance with the object to be controlled.

  According to this embodiment, it does not depend on structural requirements, such as urging | biasing force of urging means, such as the tension spring 105 shown to Fig.4 (a), and the compression spring 113 shown to Fig.3 (a)-(c). Then, the locking means including the locking portion 104a of the solenoid 104 and the locking portion 103 provided integrally with the toothless gear 102 can be reliably operated.

  Further, the rotational speed of the partial gear 102 can be made equal to or lower than the rotational speed of the speed control gear 106 regardless of the load fluctuation of the gear train 7 downstream of the drive gear 101. As a result, it is possible to prevent a collision sound or malfunction when the locking portion 104a of the solenoid 104 and the locking portion 103 provided integrally with the toothless gear 102 are locked.

  Further, the pulling force (biasing force) of the tension spring 105 serving as an urging means for returning the intermittent gear 102 to the locking position shown in FIG. Can be set regardless of force.

  In addition, it is possible to reversely rotate the missing gear 102, and as shown in FIGS. 3A to 3C, when switching a plurality of control positions of the cam 111, it is possible to select an optimal transition order. Become.

[Second Embodiment]
Next, the configuration of the second embodiment of the image forming apparatus provided with the drive control device according to the present invention will be described with reference to FIGS. In addition, what was comprised similarly to the said 1st Embodiment attaches | subjects the same member name even if the same code | symbol or a code | symbol differs, and abbreviate | omits description.

  As shown in FIGS. 6A and 6B, the drive control device 2 of the present embodiment is a missing tooth clutch in which two missing gears 502 and 503 are combined. In FIGS. 6A and 6B, reference numeral 101 denotes a drive gear. The drive gear 101 is rotated in a constant direction in the clockwise direction of FIG. 6A by a motor 9 that is controlled by the control unit 8 and that is a drive source that rotates at a predetermined timing and rotation speed. A locking portion 504 is integrally provided on one side of the intermittent gear 502 provided at a position where it can mesh with the drive gear 101 connected to the motor 9.

  The locking portion 104a of the solenoid 104 serving as the locking means is locked to a locking portion 504 provided integrally with the toothless gear 502. As a result, the toothless portion 502 a of the toothless gear 502 faces the drive gear 101 and can be stopped in a state where the tooth portion 502 c of the toothless gear 502 does not mesh with the drive gear 101.

  Further, a gear 503b is integrally provided on one side of the toothless gear 503, and a boss 503c is provided so as to protrude from one side of the gear 503b. The missing tooth portion 503a of the missing gear 503 is opposed to the drive gear 101 by an urging force of a compression spring (not shown) provided between the missing gear 502 and the missing gear 503. The tooth portion 503d can be stopped in a state where it does not mesh with the drive gear 101.

  According to the present embodiment, the solenoid 104 is released by the control unit 8. Then, the missing gear 502 starts to rotate by the biasing force of a compression spring (not shown) provided between the missing gear 502 and the missing gear 503. Then, the tooth portion 502 c of the toothless gear 502 meshes with the drive gear 101.

  An anti-rotation portion (not shown) is further formed between the partial gear 502 and the partial gear 503. When the partial gear 502 rotates by a predetermined rotation angle, the anti-rotation portion acts and is missing. The toothed gear 503 starts to rotate.

  Thereafter, the toothless gear 502 rotates once in the counterclockwise direction of FIG. 6A due to the engagement of the tooth portion 502c of the toothless gear 502 and the drive gear 101. Then, as shown in FIG. 6A, the toothless portion 502a of the toothless gear 502 is opposed to the driving gear 101 and the meshing with the driving gear 101 is released. Then, the locking portion 103 provided integrally with the toothless gear 502 and the locking portion 104a of the solenoid 104 are locked, and the rotation of the toothless gear 502 is stopped again.

  Subsequently, the partial gear 503 rotates while compressing a compression spring (not shown) provided between the partial gear 503 and the partial gear 502. Then, the toothless portion 503a of the toothless gear 503 faces the driving gear 101, and the meshing between the toothed portion 503d and the driving gear 101 is released.

  One end of a tension spring 506 serving as an urging means is locked to the apparatus frame 3, and the other end is locked to a lever 505 that is rotatable about a rotation center 505a. The boss 503c provided so as to come into contact with the lever 505 by the pulling force of the tension spring 506 is pressed by the lever 505 rotating around the rotation center 505a, and the toothless gear 503 rotates to the stop position.

  Note that the rotation range of the lever 505 around the rotation center 505a is regulated by a regulating member (not shown) provided at the rotation center 505a. Thus, the rotation of the lever 505 is prevented so that the lever 505 does not bias the boss 503c in a state where the tooth portion 503d of the toothless gear 503 is not meshed with the drive gear 101.

  A speed control gear 106 is provided at a position that can be meshed with the drive gear 101 on the same axis as the segment gear 503. The speed control gear 106 of this embodiment is always meshed with the drive gear 101 and driven to rotate. While the tooth portion 503d of the partial gear 503 meshes with the drive gear 101 and is rotationally driven, the speed control gear 106 and the partial gear 503 rotate at the same angular velocity.

  The speed control gear 106 is connected to a gear 503b provided integrally with the toothless gear 503 via a one-way clutch 107 serving as rotation suppression means. The one-way clutch 107 idles when the relative rotational directions of the gear 503b and the speed control gear 106 coincide. Further, when the rotation direction of the gear 503b and the rotation direction of the speed control gear 106 are opposite directions, they are configured to lock.

  That is, in the one-way clutch 107, the toothless gear 503 can rotate only in the reverse direction with respect to the rotation direction of the speed control gear 106. As a result, the locking portion 504 of the toothless gear 502 is locked to the locking portion 104a of the solenoid 104. The state in which the missing gear 503 is locked by the urging force of a compression spring (not shown) provided between the missing gear 502 and the missing gear 503 is as follows. The gear 503b provided integrally with the partial gear 503 and the speed control gear 106 are idled. Therefore, the operation of the drive control device 2 is not hindered.

  Here, the effect of the speed control gear 106 when the configuration of the gear train 7 downstream of the gear 503b is the same as that of the first embodiment will be described. As in the first embodiment, the pulling force (biasing force) of the tension spring 506 is a load applied to the cam 111 at all control positions of the cam 111 as shown in FIGS. It is required to set so as to overcome the torque.

  As shown in FIGS. 3A and 3B, the control position where the compression distance of the compression spring 113 is relatively small and the load is small is as follows. As shown in FIG. 3C, the rotational torque applied to the toothless gear 503 is larger than the control position where the compression distance of the compression spring 113 is relatively large and the load is large.

  As shown in FIG. 6 (a), the other end of the tension spring 506 is an urging means in which one end of a lever 505 provided so as to be rotatable about a rotation center 505a is engaged with the device frame 3. It is locked to. The lever 505 rotates about the rotation center 505a in the clockwise direction of FIG. 6A by the pulling force (biasing force) of the tension spring 506. Then, it abuts and slides on a boss 503c protruding on one side of a gear 503b provided integrally with the toothless gear 503, and presses the boss 503c in the right direction in FIG. 6 (a). As a result, the tension spring 506 serving as an urging means urges the toothless gear 503 in the counterclockwise direction of FIG.

  In some cases, the cam 111 is rotating through the gear train 7 extending from the gear 503b integrally provided to the toothless gear 503 to the gear 110 by the pulling force of the tension spring 506 shown in FIG. At that time, torque for increasing the angular velocity ω of the cam 111 is applied by the pulling force of the tension spring 506. For this reason, the gear train 7 on the downstream side of the toothless gear 503 including the cam 111 tends to rotate faster than the rotational speed given from the drive gear 101 by the pulling force of the tension spring 506.

  In the present embodiment, the speed control gear 106 is connected to the toothless gear 503 via the one-way clutch 107. For this reason, the gear train 7 downstream of the intermittent gear 503 including the cam 111 tends to rotate faster than the rotational speed given from the drive gear 101 by the pulling force of the tension spring 506. However, the rotational speed of the drive gear 101 is suppressed below the rotational speed of the drive gear 101 by the speed control gear 106 that is always meshed with the drive gear 101.

  As a result, the angular velocity of the toothless gear 503 can be kept constant as in the first embodiment, and the locking portion 104a and the locking portion of the solenoid 104 generated in each of the comparative examples shown in FIGS. It is possible to prevent a collision sound or malfunction when the 504 is locked.

  Further, as shown in FIGS. 3A to 3C, when the cam 111 having a plurality of control positions is operated, the difference in the drive torque of the cam 111 at each control position of the cam 111 is a missing gear. Does not affect the angular velocity of 503. Accordingly, parameters such as the tension spring 506 shown in FIG. 6A and the compression spring 113 shown in FIGS. 3A to 3C can be set with a sufficient margin. Other configurations are the same as those in the first embodiment, and the same effects can be obtained.

  The drive control device 2 described in the first and second embodiments is also applied to a drive control device that drives a feeding unit (sheet feeding device) 209 such as a feeding roller 210 of the image forming apparatus 201. Is possible.

2 ... Drive controller 9 ... Motor (drive source)
101… Drive gear
102 ... Missing gear
104… Solenoid (locking means)
106… Speed control gear
107… One-way clutch (rotation suppression means)
111… Cam (driven body)

Claims (5)

A driven body that is rotationally driven;
A drive gear connected to the drive source;
A toothless gear provided at a position capable of meshing with the drive gear;
Locking means for stopping the toothless portion of the toothless gear in a state where it is not meshed with the drive gear;
Urging means for urging the partial gear in the rotation direction;
Have
In the drive control device that operates the locking means at a predetermined timing to transmit rotation from the drive source to the driven body,
A speed control gear provided at a position that can be meshed with the drive gear on the same axis as the intermittent gear;
A rotation restraining means for connecting the toothless gear and the speed control gear;
A drive control device comprising:   The drive control device according to claim 1, wherein the rotation inhibiting unit is configured such that the partial gear can rotate only in the reverse direction with respect to the rotation direction of the speed control gear. Having at least two control positions by the driven body;
The reduction ratio of the gear train from the partial gear to the driven body is set so that the control position is switched by one rotation operation of the partial gear. The drive control apparatus described.   The drive control device according to claim 1, wherein the drive gear can be switched between forward rotation and reverse rotation. The drive control device according to any one of claims 1 to 4,
An image carrier on which a toner image is carried;
A transfer means controlled by a driven body that is rotationally driven by the drive control device and capable of contacting and separating from the image carrier;
An image forming apparatus comprising:

Images