JP2010224328A - Torque excess detection mechanism - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a torque excess detection mechanism for highly accurately detecting torque excess of load torque of a rotated side. <P>SOLUTION: The torque excess detection mechanism includes: a rotated member 12 engaged with a rotary member 11 by having a prescribed amount of a gap in a rotation direction and to which the rotation is transmitted by the rotary member 11; a biasing means 13 engaged with each of the rotary member 11 and the rotated member 12 and for biasing the rotary member 11 and the rotated member 12 to the rotation direction; and a detecting means 9 for detecting change of the gap of the rotation direction of the rotary member 11 and the rotated member 12. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a torque excess detection mechanism having a rotating member and a rotated member.

  In general, a mechanical device is provided with various rotating members. For example, in an image forming apparatus such as a printer, a copying machine, and a facsimile, the rotating member is used for a process unit required for image formation.

  In the image forming apparatus, after the toner image formed on the photosensitive drum is transferred to the transfer material, a cleaning device is used before the next image forming process is started so that the next image forming process is not hindered. The toner remaining on the photosensitive drum is removed. The removed toner is conveyed to a waste toner collecting container by a waste toner conveying screw, and the waste toner is accumulated in the container.

  Conventionally, a means for detecting torque received from a motor is provided between a waste toner conveying screw and a drive motor that rotationally drives the screw. If the waste toner collection container fills up due to the increase in the number of durable sheets and the rotation torque of the waste toner transport screw exceeds the specified value (overload), the drive of the waste toner transport screw is released by the torque limiter and the drive motor is damaged. And waste toner is prevented from overflowing.

  As shown in FIG. 10, the torque limiter 64 has a coupling 65 and a coupling gear 66, and the coupling 65 is fixed to the waste toner conveying screw 40 in the rotational direction and can be moved by a predetermined distance in the thrust direction. ing.

  The coupling 65 is urged in the direction of arrow A with a predetermined urging force by a spring 68, meshes with the coupling gear 66, and the driving force of the coupling gear 66 is transmitted. When a load torque of a predetermined value or more is applied to the waste toner conveying screw 40, the coupling 65 overcomes the urging force of the spring 68 and moves in the direction opposite to the arrow A direction, and the coupling gear 66 slips and idles. . As a result, the coupling 62 and the coupling gear 64 are disengaged and the driving force from the driving motor is not transmitted to the waste toner conveying screw 40.

  As a result, the driving force from the drive motor is not transmitted to the waste toner conveying screw 40 while a load of a predetermined value or more is applied to the waste toner conveying screw 40. This prevents an excessive load from being applied to the drive motor and the drive device from being damaged or waste toner overflowing from the waste toner container.

JP 2000-162945 A

  However, in the conventional example, the coupling 65 meshes with the coupling gear 66 and moves by overcoming the urging force of the spring 68, so that an overload on the rotated side is detected. For this reason, there is a situation in which overload detection cannot be accurately performed due to the influence of the shape and friction of the meshing portion of the coupling 65.

  The present invention has been made in view of the above-described circumstances, and an object thereof is to provide a torque excess detection mechanism capable of accurately detecting the torque excess of the load torque on the rotated side.

  In order to achieve the above object, a representative configuration of the present invention includes a rotating member that is engaged with the rotating member with a predetermined amount of clearance in the rotating direction, and the rotation is transmitted by the rotating member. A member, a biasing means that is engaged with each of the rotating member and the rotated member, and biases the rotating member and the rotated member in a rotating direction; and a rotation direction of the rotating member and the rotated member And detecting means for detecting a change in the gap.

  According to the present invention, excess detection of driving torque can be performed easily, inexpensively and accurately.

1 is a longitudinal sectional view showing an overall configuration of an image forming apparatus according to Embodiment 1 of the present invention. FIG. 2 is a cross-sectional view of a waste toner conveyance unit of the image forming apparatus illustrated in FIG. 1. FIG. 3 is a perspective view of the torque excess detection mechanism shown in FIG. 2. It is a disassembled perspective view of the torque excess detection mechanism of FIG. (a) is a perspective view when the load torque is less than or equal to a predetermined value in the torque excess detection mechanism of FIG. 3, and (b) is a perspective view when the load torque is greater than or equal to a predetermined value. 3A is an explanatory diagram when the load torque of the drive piece and sensor flag of the torque excess detection mechanism of FIG. 3 is a predetermined value or less, and FIG. 3B is an explanatory diagram when the load torque is a predetermined value or more. is there. (a) is explanatory drawing in case the load torque of the driven piece and sensor flag of a torque excess detection mechanism of FIG. 3 is below a predetermined value, (b) is explanatory drawing when load torque is above a predetermined value. It is. (a), (b) is a perspective view of the torque excess detection mechanism based on Embodiment 2 of this invention. It is a perspective view of the torque excess detection mechanism which concerns on Embodiment 3 of this invention. It is sectional drawing of the conventional torque excess detection mechanism.

  [Embodiment 1]

  Hereinafter, a first embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a longitudinal sectional view showing the overall configuration of a four-drum full-color image forming apparatus using an intermediate transfer belt. FIG. 2 is a cross-sectional view of the waste toner transport unit.

  In FIG. 1, 1 is a four-drum full-color image forming apparatus, 2 is a main body of the four-drum full-color image forming apparatus, and PY, PM, PC, and PBk (hereinafter referred to as P) are detachably provided in the apparatus main body 2. , Magenta, cyan, and black process cartridges, 31 is an intermediate transfer belt unit having an intermediate transfer belt 30 as an intermediate transfer member, and 25 is a fixing device.

  Each process cartridge P is disposed on the outer peripheral surface of the photosensitive drums 26Y, 26M, 26C, and 26Bk (hereinafter referred to as 26), which are image carriers, and the surface of the photosensitive drums is uniform. And a primary charger 50 that is electrically charged.

  In addition, each process cartridge P converts each color electrostatic latent image on the surface of the photosensitive drum formed by exposure by the laser exposure devices 28Y, 28M, 28C, and 28Bk to the corresponding colors of yellow, magenta, cyan, and black. A developing device 51 for developing using toner is provided, and arranged in parallel along the intermediate transfer belt 30.

  The developing roller 54 in the developing unit 51 is configured to be separated from the photosensitive drum 26 together with the developing unit 51 and to stop the rotation, thereby preventing the developer from deteriorating. Further, a primary transfer roller 52 that forms a primary transfer portion together with the photosensitive drum 26 is disposed opposite to the position where the intermediate transfer belt 30 is sandwiched with the photosensitive drum 26.

  The intermediate transfer belt unit 31 includes an intermediate transfer belt 30 and three rollers, a driving roller 100 that stretches the intermediate transfer belt 30, a tension roller 105, and a secondary transfer counter roller 108, and a belt driving motor (not shown). The intermediate transfer belt 30 is rotated and conveyed by driving the driving roller 100 to rotate.

  The belt drive motor rotationally drives the intermediate transfer belt 30 at a predetermined speed according to an instruction from the image formation control unit. All the photosensitive drums 26 are rotated at a predetermined speed by a drum drive motor (not shown) according to an instruction from the image formation control unit.

  The tension roller 105 is configured to be movable in the horizontal direction according to the length of the intermediate transfer belt 30. Further, in the vicinity of the tension roller 105, two registration detection sensors 90 and 91 for detecting a toner patch on the intermediate transfer belt 30 are provided at both ends in the roller longitudinal direction.

  Reference numeral 27 denotes a secondary transfer roller disposed at a position sandwiching the intermediate transfer belt 30 of the secondary transfer counter roller 108, and 33 denotes a transfer conveyance unit that holds the secondary transfer roller 27. Reference numeral 3 denotes a feeding unit that feeds a transfer material to a secondary transfer unit that includes a contact portion between the secondary transfer roller 27 and the secondary transfer counter roller 108 with the intermediate transfer belt 30 interposed therebetween.

  The feeding unit 3 includes a cassette 20 storing a plurality of transfer materials, a feeding roller 21, a pair of retard rollers 22 for preventing double feeding, a pair of conveying rollers 23a and 23b, a pair of registration rollers 24, and the like. A discharge roller pair 61, 62, 63 is provided on the downstream conveyance path of the fixing device 25.

  Next, an image forming operation of the 4-drum full-color image forming apparatus 1 will be described. When the image forming operation is started, the transfer material in the cassette 20 is fed by the feed roller 21 and then separated one by one by the retard roller pair 22 and then passed through the transport roller pair 23a, 23b and the like. It is conveyed to the roller pair 24.

  At this time, the registration roller pair 24 has stopped rotating, and the transfer material is abutted against the nip of the registration roller pair 24, whereby the skew of the transfer material is corrected. On the other hand, in parallel with the transfer material transport operation, for example, in the yellow process cartridge PY, the surface of the photosensitive drum 26Y is uniformly negatively charged by the primary charger 50, and then image exposure is performed by the laser exposure device 28Y. As a result, an electrostatic latent image corresponding to the yellow image component of the image signal is formed on the surface of the photosensitive drum 26Y.

  Thereafter, while the developing roller 54 in the developing device 51 is driven to rotate, the developing roller 54 comes into contact with the photosensitive drum 26Y, and the electrostatic latent image is developed with the negatively charged yellow toner by the developing device 51 to be visualized as a yellow toner image. Is done.

  The yellow toner image obtained in this way is primarily transferred onto the intermediate transfer belt 30 by the primary transfer roller 52 supplied with the primary transfer bias. Note that after the toner image is transferred, the transfer residual toner adhering to the surface of the photosensitive drum 26Y is removed by the cleaner 53.

  Such a series of toner image forming operations are sequentially performed at a predetermined timing in the other process cartridges PM, PC, and PBk, and the respective color toner images formed on the respective photosensitive drums 26 are respectively intermediated at the respective primary transfer portions. Primary transfer is performed by sequentially superposing on the transfer belt 30. When the developing operation is finished, the developing roller 54 is sequentially separated from the photosensitive drum 26 and stopped rotating in order to prevent the developer from being deteriorated even if the downstream process cartridge is in the primary transfer.

  Next, the four-color toner images transferred superimposed on the intermediate transfer belt 30 are moved to the secondary transfer portion as the intermediate transfer belt 30 rotates. Further, the transfer material whose skew has been corrected by the registration roller pair 24 is sent to the secondary transfer portion in time with the image on the intermediate transfer belt 30.

  Thereafter, the four-color toner images on the intermediate transfer belt 30 are secondarily transferred onto the transfer material by the secondary transfer roller 27 in contact with the intermediate transfer belt 30 with the transfer material interposed therebetween. The transfer material on which the toner image has been transferred is conveyed to the fixing device 25, where the toner image is fixed by being heated and pressed, and then is placed on the upper surface of the apparatus main body 2 by the discharge roller pair 61, 62, 63. Discharged and loaded.

  The intermediate transfer belt 30 that has finished the secondary transfer has the transfer residual toner remaining on the surface removed by a belt cleaner (not shown) installed in the vicinity of the drive roller 100. The removed toner is sent as a waste toner to a waste toner collecting container (not shown) by a waste toner conveying screw 40 shown in FIG.

  When the number of durable sheets increases and the waste toner is filled, the load torque acting on the waste toner conveying screw 40 increases. If this load torque becomes excessive, the drive motor, which will be described later, may be damaged or the waste toner may overflow, so the torque excess detection mechanism 200 that detects the load torque is engaged with the drive gear 10 and the waste toner conveying screw 40. .

  In the torque excess detection mechanism 200 shown in FIGS. 3 and 4, the driving gear 10 that rotates the waste toner conveying screw 40 is connected to a driving piece 11 that is a rotating member, and the driven piece 12 that is a rotated member is discarded. The toner conveying screw 40 is connected. The driven piece 12 is engaged with the driving piece 11 with a rotation play (a predetermined amount of gap), and the rotation is transmitted by the driving piece 11. Further, the spring end portion 13a and the spring end portion 13b of the torsion spring 13 engage with the groove 15 of the driving piece and the groove 16 of the driven piece, respectively, and are positioned between the driving piece 11 and the driven piece 12 (FIG. 5). reference).

  The torsion spring 13 urges the driving piece 11 and the driven piece 12 in the rotational direction with a predetermined spring force, and when there is no load torque, the surfaces 17 and 18 of the driving piece 11 and the surfaces 42 and 43 of the driven piece 12 Are in contact (see FIGS. 6 and 7). The spring pressure of the torsion spring 13 is set equal to the load torque of the waste toner conveyance screw 40 when the waste toner collection container is full, and the rated torque of the torque excess detection mechanism 100 is set to the conveyance torque when the waste toner collection container is full. .

  Reference numeral 14 denotes a sensor flag. The sensor flag 14 is movably engaged with the boss 19 of the driving piece 11 and the boss 44 of the driven piece 12 at the engaging portion thereof, and the relative relationship between the driving piece 11 and the driven piece 12 is Projects and retracts depending on the position. 9 is a photosensor having a U-shaped cross section, which is a rotation detection sensor. The sensor flag 14 enters the photosensor 9 when protruding, and blocks the detection optical axis in the photosensor 9.

  Therefore, in the torque excess detection mechanism 200, when the driving force is input to the driving gear 10 and the load torque is less than the rated torque, the driven piece 12 is attracted to the driving piece 11 by the spring pressure of the torsion spring 13.

  Then, the driving piece 11 and the driven piece 12 rotate while the surface 17 of the driving piece 11 and the surface 42 of the driven piece 12 are in contact with each other. At this time, the sensor flag 14 engaged with each of the driving piece 11 and the driven piece 12 does not protrude and rotates to the retracted position (FIGS. 5A, 6A, and 7A). )reference).

  When the load torque is equal to or greater than the rated torque, there is no play between the driving piece 11 and the driven piece 12, the surface 18 of the driving piece 11 and the surface 43 of the driven piece 12 are in contact, and the driven piece 12 is held by the driving piece 11. Rotate. At this time, the relative position of the driving top 11 and the driven top 12 changes, and the sensor flag 14 protrudes (see FIGS. 5B, 6B, and 7B).

  When the sensor flag 14 rotates in a protruding state (protruding position), the sensor flag 14 blocks the optical axis of the photosensor 9 with the rotation period of the driving top 11 and the driven top 12, and a waste toner collecting container is detected by detecting this. Is detected to be full.

  As described above, in this embodiment, the driven piece 12 that is engaged with the driving piece 11 with a predetermined amount of gap in the rotational direction is expanded in the rotational direction by the torsion spring 13. Is biased in the direction.

  When the load torque acting on the driven piece 12 is equal to or greater than a predetermined value, the engagement gap between the driving piece 11 and the driven piece 12 changes, the sensor flag 14 protrudes, and the photo sensor 9 detects this.

  As a result, it is possible to obtain an excess torque detection mechanism that can detect whether or not the load torque on the rotated side exceeds a predetermined value at low cost, simply and with high accuracy.

  As mentioned above, although embodiment of this invention was explained in full detail, this invention is not limited to the said embodiment description, In the range which does not deviate from the mind of the invention described in the claim of this invention, Various changes can be made.

[Embodiment 2]
For example, FIG. 8 shows a perspective view of a torque excess detection mechanism according to the second embodiment. Here, in FIG. 8, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  The drive gear 10 has a photo sensor flag 45, and a through hole 46 is formed through which the sensor flag 14 can protrude and retract in the thrust direction. A boss 47 is formed on the outer peripheral surface of the driven piece 12. The sensor flag 14 is engaged with the boss 47 of the driven piece 12 and the through hole 46 of the driving gear 10, and protrudes and retracts in the thrust direction of the driving gear 10 depending on the relative position of the driving piece 11 and the driven piece 12. ing.

  The sensor flag 14 protrudes from the through hole 46 of the drive gear 10 when no load torque is applied to the drive gear 10. In this case, the relationship between the drive gear 10, the drive piece 11, the driven piece 12, and the torsion spring 13 is the same as in the first embodiment, and when the sensor flag 14 rotates in a protruding state, the light of the photo sensor flag 45 The shaft is cut off.

  When driving force is input to the driving gear 10 and the load torque is less than the rated torque, the driven piece 12 is attracted to the driving piece 12 by the spring pressure of the torsion spring 13, and the sensor flag 14 rotates while protruding. (See FIG. 8 (a)).

  When the waste toner is filled in the waste toner collecting container and the load torque is equal to or higher than the rated torque, the driven top 12 is rotated by the driving top 11. At this time, the relative position of the driving top 11 and the driven top 12 changes, and the sensor flag 14 is retracted in the thrust direction (see FIG. 8B). As a result, the signal obtained by the photosensor flag 45 changes, and the fullness of the waste toner collection container is detected.

  [Embodiment 3]

  FIG. 9 is a perspective view of the torque excess detection mechanism according to the third embodiment. In FIG. 9, the same components as those in the first and second embodiments are denoted by the same reference numerals, and the description thereof is omitted.

  The torque excess detection mechanism shown in FIG. 9 is provided with a driven piece 73 that engages with a driven piece 70 with a rotational backlash, and has sensor flags 72 and 75. Two torsion springs (not shown) having different spring pressures are interposed between the driven piece 70 and the driven piece 73.

  The drive gear 10 has through holes 46 and 48, and the sensor flags 72 and 75 are engaged with the bosses 71 and 74 formed on the outer periphery of the driven pieces 70 and 73 and the through holes 46 and 48 of the drive gear 10. The driven gear 70 and the driven piece 73 are projected and retracted in the thrust direction of the driving gear 10 depending on the relative positions of the driven piece 70 and the driven piece 73.

  The spring pressure of one torsion spring is the spring pressure that the sensor flag 72 retracts when the waste toner collection container is full, and the sensor flag 75 is retracted before the waste toner collection container is filled with the spring pressure of the other torsion spring. Use spring pressure.

  When the torque acting on the drive gear 10 is equal to or less than the rated torque set by the spring pressure of the torsion spring, the sensor flags 72 and 75 rotate in a state of protruding. At this time, the waste toner collecting container is not full.

  When the load torque is not less than the rated torque set by the spring pressure of the other torsion spring and not more than the rated torque set by the spring pressure of the one torsion spring, the sensor flag 75 rotates and the sensor flag 72 rotates. By detecting this state, it can be notified that the waste toner collecting container is approaching full. By recognizing that the waste toner collection container is almost full, it is possible to prepare replacement parts in advance before the waste toner collection container is full.

  When the load torque is equal to or greater than the rated torque set by the spring pressure of one of the torsion springs, both the sensor flags 72 and 75 rotate in the retracted state, and the fullness of the waste toner collection container is detected.

  As described above, in this embodiment, it is possible to detect multi-stage torque by detecting the states of a plurality of sensor flags, and even in the case of having a plurality of driven elements by using them in parallel, Excess detection is possible.

1 ... 4 drum full color image forming device 9 ... Photo sensor
10 Drive gear
11 …… Drive top
12 …… Driven top
13 Torsion spring
14 Sensor flag
200 ... Torque excess detection mechanism

Claims (6)

A rotating member is engaged with the rotating member with a predetermined amount of clearance in the rotating direction, and the rotating member to which rotation is transmitted by the rotating member is engaged with each of the rotating member and the rotated member. And an urging means for urging the rotating member and the rotated member in the rotating direction, and a detecting means for detecting a change in a gap in the rotating direction between the rotating member and the rotated member. Torque excess detection mechanism. 2. The biasing means biases the rotating member and the rotated member in a direction in which a gap of engagement between the rotating member and the rotated member expands with respect to a rotating direction. Torque excess detection mechanism described in 1. The detecting means includes a sensor flag that is movably held between a protruding position and a retracted position in accordance with a change in a rotation direction gap between the rotating member and the rotated member, and the sensor flag is at the protruding position. The over-torque detection mechanism according to claim 1, further comprising: a rotation detection sensor provided at a position shielded from light by the sensor flag. The torque excess detection mechanism according to claim 3, wherein the sensor flag includes an engaging portion that engages with each of the rotating member and the rotated member. The torque excess detection mechanism according to claim 3, wherein the rotation detection sensor is shielded at a rotation cycle of the rotation member and the rotated member. 2. The torque according to claim 1, wherein torque excess detection in multiple stages and torque excess detection of the plurality of rotated members are enabled by using the plurality of rotating members and the plurality of detecting means. Excess detection mechanism.

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